Lithofacies and depositional environment of Gombe ...

26 th Colloquium of African Geology / 23 - 27 NOVEMBER 2016 / International Conference Centre, University of Ibadan, Ibadan, Nigeria / Abstracts Volume

Geochemistry of Kerku Ring Complex, North Central Nigeria 1

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S. S. Magaji , E. C. Ike and R. F. Martin

1 Department of Geology, Ahmadu Bello University, Zaria, Nigeria 2 Federal University, of Technology, Owerri, Nigeria 3 Earth and Planetary Sciences Department, McGill University, Montreal, Canada

Corresponding author:[email protected]

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he Kerku magmatic complex is one of the few magmatic centres within the Jurassic Nigerian Younger Granites Province that is yet to fully characterized chemically. This complex was emplaced during Jurassic anorogenic magmatism that occurred 400Ma after the cessation of Pan-African orogeny. The rock suite within the complex ranges from syenite to alkali quartz syenites and peralkaline granite. These rocks define a continuous chemical evolutionary trend and reveal a correlation between decreasing age and increasing silica content. The members of the suite display A-type characteristics and are genetically linked through fractionation to the more felsic ones. The syenites are hypersolvus and contains a ferro-richterite amphibole as the dominant femic mineral, whereas the most evolved alkali feldspar granite is subsolvus and contains annite as the dominant femic mineral. The rock suite display A-type characteristics and are genetically linked through fractionation to the more felsic members. Extensive anhydrous fractionation (49.0%), of alkalifeldspar, clinopyroxene, and minor Ti-oxide and apatite from parental syenitic magmas, represented by the syenitic rocks, produced the granite melt now represented by the alkali feldspar granite. Textural evidence points to the crystallization of these minerals from an interstitial femic melt present at the solidus of these rocks, in which magnesium is a trace constituent. Such a late stage melt appears because of the low thermal stability of these extremely Fe-enriched minerals and the massive removal of alkali feldspar. Chemically the rock suite ranges from 57.85 to 72.83 wt. % SiO2 with differentiation index (DI) ranging from 72.80 to 94.90.The rock assemblage in Kerku complex consists of syenites, quartz syenites, and peralkaline granites. Regarded as a representative example for similar A-type outcrops in this region, this petrogenetic model further suggests that Jurassic Atype magmatism in the Nigerian Younger Granite Province represents a significant anorogenic addition of lower crustal material to the Nigerian Jurassic crust. The suite shows a classic sequence of rocks related by fractional crystallization of a parental magma, leading to the pseudotenary minimum in the granite system.

“Geochemistry of the Bitungulu Lava Flow of the January 17th, 2002 Nyiragongo Volcano Eruption (Virunga, East-African Rift)” 1

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Ephrem Kamate Kaleghetso , Katcho Karume , Kambale Kavuke 1

Department of Geodesy, Goma Volcano Observatory, North-Kivu, D. R.Congo ([email protected] ) 2 Department Geochemistry, Goma Volcano Observatory, North-Kivu, D.R. Congo 3 Department of Geodesy,Goma Volcano Observatory, North-Kivu, D. R. Congo

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he East African rifts system is defined by structural and magmatic features. The dating of volcanic strata reveals a logic model in the spatial development of this rifts system in which is the Virunga volcanic province. This volcanic province, recently active in mid-Miocene, is above an abnormally hot asthenosphere (1); some authors believe, moreover, that it is representative of hot spots volcanism in the African tectonic plate (2). It is in the western branch of the East African rift that is localized the Virunga volcanic province which includes the Nyiragongo volcano. Nyiragongo volcano is well known for its lava lake and its eruptive dynamism of Hawaiian type (3). In 1995, the surface of this lava lake solidified; leaving thus the magma below. The increasing of the pressure inside the solid layer would facilitate the discharge of the magma in the main fractures of the PAGE

Unlocking Earth Science Potentials for Sustainable Development of Africa

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flanks of Nyiragongo. Besides this magmatic pressure, the local fractures system that results from tectonic seismicity common in the region is an important factor for the eruptive dynamism of the Nyiragongo. By way of illustration, some assumptions suggest that at the time of the eruption of January 17, 2002, the energy which contributed to the massive fracturing was helped by regional tectonic events. This events consensus was then sufficient to cause an eruption. Therefore, this eruption of 2002 had three leaving lava points thus corresponding to three different branches of lava flows, including Shaheru, Munigi and Bitungulu lava flows. The objective of this work was to describe the geochemical characteristics of rocks of the Bitungulu lava flow of the January 17, 2002 Nyiragongo volcano eruption. In addition to the description in situ, samples of these rocks were analyzed in the University of Lubumbashi laboratory. Results show a high concentration of silica and mineralization dominated by nepheline. These rocks are basalts but they are close to trachy-basalts.

Geochemistry of the K-rich Granitoids in the Bole-Nangodibelt of the Paleoproterozoic Birimian Province of Ghana RaudaAddae1, Patrick Sakyi1, Daniel Asiedu1, Samuel Dampare2 1

Department of Earth Science, University of Ghana, Legon-Accra, Ghana.([email protected]) 2 School of Nuclear and Allied Sciences, University of Ghana, Legon-Accra, Ghana

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he Paleoproterozoic Birimian province of Ghana is made up basically of parallel and equally spaced NE-SW trending belts (with the exception of one which trends N-S), one of which is the Bole-Nangodi belt which outcrops in the northern parts of Ghana. These belts petrologically consists of metasedimentary and metavolcanic rocks, both of which are intruded by granitoids of various ages. These granitoids can broadly be grouped into four; the Cape Coast, Winneba, Dixcove and Bongo (and Banso) granitoids. Of interest to this study is the Bongo granitoids (2097±3 Ma)in the Bole-Nangodi belt. Geochemical studies of the granitoids help unravel the petrogenesis and tectonic settings of these rocks, aiding in the generation of a robust model for the entire evolution of the Paleoproterozoic Birimian province of Ghana. Geochemical classifications categorizes these rocks into granite, granodiorite, monazite and quartz monazite. The rocks are mineralogical composed of K-feldspar, quartz, ±plagioclase, ±hornblende, ±pyroxene, ±biotite and ±muscovite. Accessories include, opaque oxides/sulphides, titanite, zircon, epiodote, allanite, carbonate, fluorite and apatite. The granitoids are K-rich and have high SiO2, Na2O, K2O and low MgO contents with characteristically high concentrations of Rb, Ba, Sr, Cr and Ni. They can be classified as calc-alkalinemetaluminousto slightly peraluminous I-S-type granitoids mostly showing affinity for A-type granitoids. They are mostly shoshonitic and magnesian, and are enriched in LILEs and LRREs and depleted in HFSEs and HREEs, with almost negligible negative Eu anomalies to slightly positive Eu anomaly. The 87Sr/86Sr and 143Nd/144Nd range between 0.7090-1.8622 and 0.510987 86 143 144 0.5129 respectively with initial Sr/ Sr and initial Nd/ Nd ratios calculated for a crystallization age of 2.1Ga in the range of 0.5987-1.8115 and 0.4763-0.5101 respectively. ?Ndt(2.1Ga) values range from -1.0 to +8.3. TheNd-TDM model ages (two stages) range between 1.77-2.99Ga and 1.7-2.2Ga for TDM1 and TDM2 respectively. The granitoids are volcanic arc and syn-collisional granites with few within-plate types. They are mostly late to post-orogenic and show emplacement temperature and pressure conditions of approximately 780°C-900°C and 5-10kbar (lower temperatures and pressures are however recorded) respectively. The geochemical characteristics of these rocks indicate magma mixing and assimilation fractional crystallization of mafic melts form magma sources and crustal source melts (mostly felsic). Hence, initial thickening of crust by arc-collision (continental), PAGE


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followed by slab subduction under high pressure and temperature conditions resulting in underplating of mafic magmas in shallow crustal levels is likely to have to have generated thee K-rich granitoids. However, there might have been a shift in tectonic regime from compressional to tensional as evidenced by crustal thinning in late-post collisional extension regimes as a resultof slab roll-back and back-arc tectonic settings associated with the granitoids. Keywords:

Birimian, Paleoproterozoic, Bongo, potassium-rich granitoids, geochemistry, Sr-Nd isotope.

Les Enclaves Magmatiques Sombres (EMS) Des Massifs Granitiques de L'ait-Oklan Et Du Teg-orak (Hoggar – Algerie). Nour-Eddine

BOULFELFEL*

*Commissariat à l'Energie Atomique (COMENA) Centre de Recherche Nucléaire de Tamanrasset (CRNT)BP 443, Sorro - Tamanrasset – Algerie

Résumé :

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omme d'autres critères pétrologiques ou géochimiques la nature des enclaves est susceptible d'apporter des informations sur l'origine des magmas. Elle permet de distinguer les granites d'origine crustale, les granites mantellique et les granites mixtes. Les premiers contiennent en abondance des enclaves surmicacées mais pas d'enclaves microgrenues sombres. Les seconds contiennent des enclaves microgrenues sombres mais pas d'enclaves surmicacées. Les derniers qui seront d'ailleurs les plus nombreux, puisqu'ils correspondent au vaste ensemble des granodiorites et monzogranites orogéniques, contiennent à la fois des enclaves microgrenues sombres et des enclaves surmicacées. Quant aux xénolites et les enclaves microgrenues claires, on les trouve dans les intrusions, quelle que soit leur nature pétrographique. Ce sont des enclaves caractéristiques de la mise en place intrusive. Très peu d'enclaves magmatiques ont été observées dans ces massifs. C'est dans le granite central fin qu'on a pu observer ce phénomène. Ce sont des enclaves microgrenues, avec des tailles extrêmement variables. Les plus courantes sont centimétriques, elles ont une forme ovoïde et un contour arrondi et sont constituées par des roches magmatiques microgrenues, ou à grain fin, en contact net ou diffus avec leur roche hôte. La possibilité d'une fusion fractionnée à partir du manteau expliquerait la présence simultanée de magmas acide et basique correspondant à des degrés différents de fusion du matériel mantellique.

Mots clés: Magmas, granites, enclaves, EMS, Hoggar.

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Mineral Chemistry and the P-T Conditions of the Rocks from Southwest Obudu Plateau, Southeastern Nigeria. *Ekere E. Ukwang1, Barth N. Ekwueme1 and Anne Nedelec2. 1

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Department of Geology, University of Calabar, P.M.B. 1115, Calabar, Nigeria. Universitepaul-Sabatier, UMR 5563-LMTG, Geodynamique, 38 rue des 36-ponts, 31400 Toulouse, France. *e-mail: [email protected]

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he southwest of ObuduPlateau, southeastern Nigeria is a part of the Nigerian segment of the Bemenda Massif. The area consists of high-grade orthogneisses, paragneisses and metaperidotite. Granites, pegmatites, aplites, quartzo-feldspathic veins and dolerites intruded these gneisses. Evidence of polyphase deformation abounds such as N- and M-folds. The dominant structural trend is Pan-African (N - S to NE - SW) with sporadic pre-Pan-African structures trending E - W and NW - SE in the granulite facies rocks. Geochemical signatures indicate that these gneisses are of calcic to sub-alkaline protolith. Microprobe analyses reveal that the garnet is dominantly almandine (> 70 percent) and pyrope (> 15 percent). Spessartine and grossularite occur in insignificant amounts. The mole fraction of iron (XFe) in garnet varies between 0.8 - 0.83 for the core and between 0.83 0.85 for the rim. The percentage mole fraction of phlogopite (81.55 percent) is higher in the garnet-biotite gneiss than in the granulite facies rocks. Flourphlogopite dominates with values > 60 percent, followed by annite (>19 percent). Amphibole occurring in the granulite facies rocks (charnockitic gneisses), and hornblende-biotite gneiss in the area is calcium-rich variety, with pargasite (> 36 percent) and edenite (> 30 percent) dominating. The proportion of tschermakite molecule is relatively high (> 20 percent). Pyroxene in the charnockitic gneisses is mostly clinopyroxene with Jd: Ts< 0.5. The clinopyroxenes are dominantly magnesiansalite (71 - 91 percent), augite (6 - 22 percent) and ferroaugite (2 - 7 percent). Metamorphism in the area attained the upper amphibolite - granulite facies. Computed data suggest that the metamorphic minerals in the o granulite facies rocks equilibrated at temperatures ranging from 580 to 695 C and pressures from o 5.40 to 6.00 Kbars. The meta-peridotite gave equilibration temperatures between 730 and 750 C and pressures varying between 5.73 and 6.95 Kbars. The thermal history of the charnockitic gneisses and the meta-peridotite suggest that the mafic rocks were emplaced at the peak of prograde metamorphism. The thermotectonic episodes could have been enhanced by the mafic magmas injection with subsequent orogenic activity.

Mineralogical and Chemical Changes Across Iwaraja Shear Zone, Southwestern Nigeria: Implication on the Role of Pan-African Orogenesis. 1

Blessing Adeoti and 2Chukwuemeka T. Okonkwo

1,2

Department of Applied Geology, Federal University of Technology Akure, P.M.B 704, Akure, Ondo State, Nigeria 1 corresponding author: [email protected], [email protected] 2 [email protected], [email protected]

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he mineralogical and chemical changes of the granitic gneiss across the Iwaraja shear zone were investigated for improved understanding of the deformation condition of Iwaraja shear zone. The deformation involved mylonitisation of the affected rocks with intensity ranging from protomylonite to ultramylonite under retrograde mineralogical evolution. The primary mineral composition of the granitic gneiss protolith comprises perthitic microcline (34%), plagioclase (22%), quartz (20%), and biotite (11%) with some hornblende (~3%). The mineralogy of the granitic gneiss mylonites comprises microcline (19%), quartz (41%) in matrix grains of chlorite, epidote, sericite and opaque minerals which make ~40%. The metamorphism is typically from amphibolite to PAGE


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greenschist facies conditions. Isocon plots indicated very high chemical changes during the evolution of the Iwaraja shear zone. Progressive mylonitisation of the granitic gneiss shows relatively high enrichment of Fe2O3, TiO2, MgO, CaO, P2O5, MnO and Eu, Zr and Sc and very high depletion of Na2O and Rb. The depletion trends of Na2O and Rb are similar throughout the mylonitisation. This enrichment-depletion characteristics show the influence of fluids and tectonic mixing between the granitic gneiss and rheologically stiffer pegmatite dyke, which also characterised the mineralogical transformation during the evolution of the Iwaraja shear zone. The chemical changes across the Iwaraja shear zone is seen as a CaO-MgO-Fe2O3-metasomatised and Na2O-depleted granitic gneiss mylonite under retrograde mineralogical evolution. These events are part of the chemical evolution associated with the Pan-African orogenesis during the terrain assemblage of the Nigeria segment of the Trans-Sharan Belt.

New Age Constraints on the Neoproterozoic Sijarira Group, in the Chizarira Hills, Western Zimbabwe, with Implications for Regional Correlations 1,2

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Sharad Master , Sarah M. Glynn , Michael Wiedenbeck 1

Economic Geology Research Institute School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa, [email protected] 3 Helmholtz Zentrum Potsdam, Telegrafenberg, Potsdam, Germany

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he Sijarira Group is a redbed sequence of continental fluviatile and shallow-marine origin, which outcrops in western Zimbabwe in the Chizarira Hills (where it is up to 660 m thick) and in the Hurungwe area (where it is overthrust by the “Urungwe klippe”, which contains carbonate rocks and a glacial diamictite, of Neoproterozoic age). Although the unmetamorphosed Sijarira Group has not been dated, it overlies the Badze granite which has a (reset) Rb-Sr muscovite age of c. 1211 Ma. It is aligned with, and has been regarded as a continuation of, the Tsumis-Ghanzi belt of early Neoproterozoic redbeds extending across Namibia and northern Botswana. We collected a sample of coarse-grained sandstone at 17° 39' 04.0” S; 27° 51' 21.0” E, in the Chizarira Hills. Our sample ZMB13/2 comes from the Ruziruhuru Formation of the Lubu Subgroup, overlying the basal conglomerates of the Sijarira Group. The sandstone is coarse-grained and arkosic, with a pale pink colour and is characterized by the presence of trough crossbedding. It resembles fluviatile sandstones that are commonly found associated with braided river environments. The sandstone consists of a mixture of quartz, feldspar and lithic fragments cemented together by a fine-grained, maroon coloured matrix. The fragments range in composition from subrounded grains of (polycrystalline) quartz to irregularly shaped chert fragments. The detrital zircon grains from the sandstone are for the most part sub-angular, with a small number still retaining their euhedral shape. A total of 25 spots on 24 grains were measured for U/Pb isotope dating using the Cameca 1280-HR SIMS instrument at the Helmholtz Zentrum Potsdam. The two oldest detrital zircon grains, which are slightly discordant, give ages of c. 1.8 Ga, pointing to a source from the Magondi Belt, where the ages of metamorphism are between 2.0 and 1.8 Ga. The vast majority (80%) of the zircons record an age of c. 1035 Ma. The source of these zircons, the only recorded instance of detrital zircons of this age within the region, is uncertain, but their ages are similar to the ages of pegmatites occurring in both the Choma-Kalomo Block and the Dete-Kamativi Inlier. The three youngest detrital zircons from the Sijarira sandstone are dated at c. 632 Ma, which gives a maximum depositional age for the Sijarira Group. Our data indicate that the Sijarira Group is probably derived from erosion of a hitherto unknown late Mesoproterozoic (c. 1.05 Ga) pegmatite province intruded into the Palaeoproterozoic Magondi belt, with minor provenance from PAGE


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Neoproterozoic rocks. The origin of these pegmatites may be related to tectonic events in the ChomaKalomo Block and Dete-Kamativi regions, along the northwestern edge of the Kalahari Craton. The Sijarira Group cannot be regarded as a molasse of the Pan-African Zambezi Belt, since it contains very few Neoproterozoic zircons, and the palaeocurrents were in general from E to W. Its former correlation with the Ghanzi Group of Botswana also cannot be sustained, since the Ghanzi Group has no glacial diamictites, and is probably pre-Sturtian (i.e., > c. 710 Ma) (Lehmann et al., 2015, Ore Geology Reviews, 71, 161-190), while the Sijarira Group is constrained to be < c. 632 Ma.

Paleoproterozoic Magmatism in Jebba-Bode Saadu Area, Southwestern Nigeria and Its Implications for the Tectonic Evolution of the Area 1

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Chukwuemeka T. Okonkwo & Valentin Y. Ganev 1

Department of Applied Geology, Federal University of Technology, Akure, Nigeria Department of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Sofia, Bulgaria

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arge tracts of Jebba-Bode Saadu area, southwestern Nigeria, is underlain by orthogneisses of granitic to dioritic composition. These rocks have been subjected to several phases of both ductile and brittle deformation. They have been intruded by largely, undeformed, granitic rocks of probable Pan-African (ca. 600 Ma) age. Four suites of orthogneisses outcropping in the area have yielded upper intercept U-Pb on zircon ages of 2207±20 Ma, 2236±29 Ma, 2228±32 Ma and 2179±28 Ma indicating the time of crystallization of these rocks. The gneisses bear the imprints of several deformation events in the form of foliations, folds and shear zones. The geochemical and geochronological data from these orthogneisses indicate an important period of crust formation associated with orogenic activity during the Paleoproterozoic Eburnean orogeny. The older members i.e. the Egba Granodioritic Gneiss, the Egba Migmatitic Gneiss and the Jebba Granitic Gneiss carry structural fabrics and early, isoclinals, folds (D1) which were developed before the emplacement of the Bode Saadu Granodioritic Gneiss. While the Egba and Bode Saadu gneisses have arc/syncollisional affinities, the Jebba Gneiss was associated with crustal extension, perhaps in a back-arc environment. These rocks intruded an old ersupracrustal sequence of metasedimentary rocks. The lithologic association and sequence of geological evolution is similar to what has been documented in the Central Hoggar domain of the Tuareg Shield and the Borborema Province of Brazil. Thereby suggesting their contiguity and common evolution during the Proterozoic.

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Rb-Sr and Sm – Nd Isotope Geochemistry of Subduction-Related Magmatism Beneath Gold Rich Ilesha Schist Belt, Southwestern Nigeria. 1

Afolabi, O. A.* and Olatunji A. S. 1

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Ladoke Akintola University of Technology, Nigeria 2 University of Ibadan, Nigeria.

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m-Nd Isotope geochemistry is used to evaluate mantle source region for some meta-volcanic rocks in the gold bearing Ilesha Schist belt restricted to the southwestern part of the Precambrian Basement Complex of Nigeria. Back arc environment with passive margin signatures have been described for the diverse lithologies within the Ife-Ilesha gold rich schist belt. Metavolcanics, metabasalts and weakly metamorphosed granites, are structurally controlled lithologies within the predominantly metapelitic schist belt. This study investigates the origin and chemical character of the mantle source for the metavolcanics. Samples of post collisional granite and its closely associated meta-basalt analysed for Rb-Sr and SmNd isotopic compositions yielded initial 87Sr/86Sr(I) (0.706) and 143Nd/144Nd(I) (0.509) and åNd values of -21.13 and -8.02 respectively suggesting enriched mantle sources or crustal source enriched protomaterial. Nd model ages for CHondrite Uniform Reservoir (TCHUR) recorded are 2.29 and 2.00 Ga each for the granite and meta-basalt rocks. Close crustal-residence ages may infer fractional melting from same parent magma for both rock types. Whole rock geochemical data used to investigate comagmatism reveals subalkaline magmatism for both lithologies. Possible magmatic differentiation occurring concomitantly with partial melting may be responsible for the calc-alkaline affinities and tholeiitic for the subduction related granite and metabasalt occurrences respectively. Chondrite normalised La/YbN ratio ranges from 13.46 – 42.23 and 0.84 – 1.69 while Eu/Eu* anomaly yielded values ranging from 0.52 – 0.74 and 0.86 – 1.05 for granite and matabasalt respectively. Nb/Ta and Rb/Sr values for granite range from 9.0 – 13.33 and 0.17 – 0.39 respectively. The metabasalt showed Nb/Ta (7.20 – 13.50) and Rb/Sr (0.01 – 0.3). Observations strongly suggest that both rock types may share the same parentage derived from an Enriched mantle type II (EMII) magma. Magmatic differentiation may occur shortly after fractional partial melting might have ensued. Field evidences as well as close TCHUR values may infer high level magmatism in a relatively thickening Precambrian crust. Isochron age calculations yielded PostArchean to early Paleao-Proterozoic age (2.5 Ga) for mantle melting which produced subalkaline Tholeiitic metabasalt and Calc-alkaline granites.

Textural and Geochemical Evidence of Magma Diversity at the Baossi Monogenetic Volcanoes, Adamawa plateau, Cameroon Volcanic Line 1,2

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Anicet Tiabou Feudjio , Robert Temdjim , Che Vivian Bih , Pierre Wotchoko3, François Xavier Mebara Onana2,4 and Caroline Ngwa Neh4 1

Remote Sensing Unit, Department of Geology, University of Buea,Cameroon([email protected]) 2 Department of Earth Sciences, University of Yaoundé 1, Cameroon 3 Department of Geology, University of Bamenda, Cameroon 4 Institute for Geological and Mining Research (IRGM), Cameroon

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asaltic lava flows are exposed at the Baossi monogenetic volcanoes, Adamawa Plateau, located in the northern part of the Cameroon volcanic line (CVL). These lava erupted from monogenetic volcanoes can exhibit great complexities in their compositional features and petrogenesis that were investigated through geochemical analysis of a suite of samples. Here we present major, trace and REE element data together with microscopic study of lava flows from the Baossi-Warack volcanic field, based on comprehensive sampling of the recently established PAGE


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stratigraphy of these monogenetic volcanoes. The volcanic rocks described are mainly composed of olivine, clinopyroxene, plagioclase and titanomagnetite oxides. The petrographic studies, also show that these lavas are characterised by two generations of olivine and clinopyroxenephenocrysts set in a fine porphyritic groundmass, with elongated and sometimes zoned plagioclase. These distinguishable generations of minerals suggest two different batches of magma involved in the emplacement of the volcanic cones through fissures fromthe lower mantle and the crust. Geochemical data reveals that the lava flows are basanite, basalt and hawaiite (SiO2: 40.76 51.39 wt%, MgO: 4.98 9.99 wt%). From bivariate plots (eg. K2O/SiO2; MgO/SiO2; Ti2O/SiO2 and P2O5/SiO2) two different liquid lines of descent are established as a result of different batches of

The Evolution and Origin of K-Feldspar Megacrysts in Porphyritic Granite of Abeokuta Area, Southwestern Nigeria Igonor E. E., Adeoti B. and Sulaiman T. I. Department of Applied Geology, Federal University of Technology Akure, P.M.B 704, Akure, Ondo State, Nigeria 1 [email protected], [email protected]

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he geological assessment of Abeokuta area revealed that the basement complex rocks comprise migmatite-gneiss, granite-gneiss, biotite granite and porphyritic granite. The granites are probable of Pan-African age (ca. 600Ma). K-feldspar megacrysts in the porphyritic granite were studied in order to understand the effect of Pan-African orogenesis on the evolution of the K-feldspar megacryst as well as to infer possible origin for the porphyritic granite. The length, width, orientation of both axes of 1500 megacrysts of K-feldspar were taken and analysed. The result of strain analyses indicated maximum elongation of the megacrysts in NE-SW and NNW-SSE with maximum strain (ó3)of 2.963 and 2.959 respectively, with long axis of the strain ellipsoid oriented in 054o (NE-SW). This orientation is interpreted as the effect of Pan-African orogenesis. The compressional strain (1) corresponds to NW-SE, E-W and WNW-ESE indicating the minimum stress direction. Plots of Cystal Size Distribution (CSD) of K-feldspar megacrysts showed dominantly concave-downward curves suggesting crystals that are formed by textural coarsening processes and are originated from a hybrid magma that have undergone differentiation during magma ascent. The orientations of most of the megacrysts are controlled along the direction of PanAfrican transport (NE-SW and NNW-SSE) and few others in approximately E-W direction, which we interpreted as direction of minimum stress.

Timing of Granulite-Grade Metamorphism in EAO Nappe, Uganda Hannu Mäkitie1, Irmeli Mänttäri1, Peter Mawejje2, 1 1 3 Alexander Middleton , Hugh O'Brien and Tapio Ruotoistenmäki 1

2

Geological Survey of Finland, P.O. Box 96, 02151 Espoo, Finland ([email protected]) Department of Geological Survey and Mines, Plot 21-29, Johnstone Road, Entebbe, Uganda 3 Retired from the Geological Survey of Finland, present address: [email protected]

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n situ LA-ICP-MS zircon U?Pb ages are presented for supracrustal granulites and plutonic rocks 1,2 located in the East African Orogen (EAO)high-grade metamorphic nappe thrust westwards on to Archaean basement in the Kalongo region, NE Uganda.The dated detrital zircon grains, scarce in number, indicate 2.7?2.6 Ga, 2.1?2.0 Ga and 1.1?0.9 Ga ages for the sources of the pelitic granulites. The studied granulites have evidently undergone peak metamorphism at ~0.70?0.80 Ga based on lower intercept ages; more precise agesare706±11 Mafora migmatiticsillimanite-garnet PAGE


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gneiss located in the eastern part of the nappe and 760±20 Ma foran orthopyroxene-garnet diatexite from the middle part of the nappe. Similar ages have been obtained from nearby charno-enderbite 3 (737±11 Ma ).Adjacent to the decollement, crystallization ageof intensively deformed charnockite with elongated fayalite and hedenbergite grains parallel to the rock trend is 693±19 Ma. Crystallization age of gneissic garnet-biotite granitoid located fairly closeis 690±20 Ma.These two ages are coeval with magmatic rock ages reported earlier from the same area (697±8 Ma and 694±10 3 Ma granites ).The range of ages in the nappe suggests it may comprise tectonic sub-units.

Zircon Typology and Reworking of Archaean Crust in the Nigerian Proterozoic Belt of West Africa 1

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Dada S. S. , Bruguier O. , Oha I. , Goki N. 1

Kwara State University, Malete, PMB 1530, Ilorin, Nigeria; University of Science and Technology, Montpellier, France; 3 University of Nigeria, Nsukka, Nigeria; 4 Nasarawa State University, Keffi, Nigeria.

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ultiple approaches of geochronological methods in the last half of the 19 century has led to a progressive understanding of the early crustal development in many high-grade terrains. The Proterozoic mobile belt of West Africa, including the Nigerian terrain that was for a long time regarded as essentially Pan-African has by the close of the century recorded primitive relict Archaean ages from its metamorphic assemblages. Detailed study of the typology of the zircons used in the U-Pb age determinations and those of the accessory minerals from its polycyclic gneissic components not only corroborate the existing Rb-Sr, Sm-Nd and U-Pb isotopic data but refine the petrogenetic regimes. The early Archaean granitoid magmatic inner rims appear to T surround older inherited xenocrysticcores of early(= 3.6Ga)granitoid component recorded by Nd crustal formation ages. The succeeding zone represents mid-Archaean (~3.0Ga) metamorphic event, finally rimmed by the outer neo formed Neoproterozoic amphibolites facies orthogneisses that yield ages between 600 and 640 Ma. Our study suggests that the Migmatite Gneiss Complex (MGC) in Nigeria and most probably in the entire West African and Northeastern Brazilian Borborema mobile belt consists largely of Archaean crust that was strongly reworked during the Pan-African/Braziliano event and experienced high-grade metamorphism between 600 and 640 Ma. These ages suggest that large regions of the West Gondwana was involved in the Neoproterozoic intraplate magmatism that was induced by the delamination of the thickened lithosphere due to the continental collisional at the peak of the Pan-African orogeny, resulting in structural reworking and almost total obliteration of earlier tectonic fabrics.

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The Cordierite-Orthoamphibole Rocks of The Variscan Dome of Gavarnie-Gèdre-Héas: The Gedrite of Gèdre (Hautes Pyrénées, France) Youssef Driouch1, Pierre Debat2, Jerome Ganne2, Didier Béziat2, 3 4 Leo M. Kriegsman and Jacques Martignole 1

Département de Géologie. Laboratoire LGRN. Université Mohamed Ben Abdellah. Faculté des Sciences Dhar El Mahraz. B.P. 1796. Fès-Atlas. Fès. Morocco ([email protected]) 2 Laboratoire GET, Université Paul Sabatier. Toulouse, CNRS, IRD, OMP, 14 Avenue Edouard Belin, 31400 Toulouse, France ([email protected]; [email protected]; [email protected]) 3 NCB Naturalis, Geology, Leiden, Netherlands ([email protected]) 4 Département de géologie, Université de Montréal CP 6128, Montréal, H3C 3J7, Qc, Canada ([email protected])

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he low-P/high-T Variscan metamorphic dome of Gavarnie-Gèdre-Héas, Central Pyrenees, harbours a small (1 m3), but special cordierite - and gedrite - bearing enclave, embedded within an anatectic granite. Compared to other orthoamphibole occurrences described in the literature, the enclave shows singular characters: 1) its unique mineral composition with cordierite + gedrite + biotite + staurolite + garnet + spinel + corundum + ilmenite + sulfides and tourmaline, but lacking quartz, feldspars and aluminosilicates; 2) its chemical composition with low SiO2, high Al2O3, K2O and TiO2 and high Fe2O3T/MgO. Crd-Ged-bearing rocks also occur as thin layers in layered migmatites that show a mineral composition (Bt, Crd, Ged, Pl, Qtz, Ilm, Grt, ±St) and a chemical composition more akin to other described occurrences. The cordierite-gedrite enclave records a succession of metamorphic reactions deduced from reaction textures and balanced by mass balance calculation method using stoichiometrically ideal mineral formulae close to the measured compositions:1) local Crd+Oam+Ilm±Grt growth at the expense of biotite Bt+SiO2 = Oam (Ged+Ath)+Crd+Ilm+K2O+H2O and Bt=Ged+Grt+Crd+Ilm+K2O+H2O; 2) massive development of coronas of cordierite±ilmenite±garnet around staurolite: Bt+St+SiO2=Crd+Ilm+K2O+H2O; Bt+St+SiO2 = Grt+Crd+Ilm+K2O+H2O, Ged+St+SiO2 = Crd±Ilm+H2Oand Ged+St = Grt+Crd+Ilm+H2O; 3) isochemicalde composition of staurolite into cordierite + spinel + corundum: St = Crd+Spl+Crn+V.In the gedrite-bearing layers of interlayered migmatites, the formation of the Crd-Oam assemblage involves the consumption of biotite, plagioclase and quartz in the subsolidus. Mass balance calculations show that in the enclave most reactions took place in an open system with addition of silica and release of K2O during the anatexis and the cooling of surrounding migmatitic and anatectic rocks. Performed Perple_X pseudosections indicate a clockwise P-T path, with hightemperature conditions (700 - 730 °C) at decreasing pressure (from 5.5 to 3 kbar). This fits the P - T path of other metamorphic domes of the Variscan Central Pyrenees.

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Did the Final Collision Zone Between East and West Gondwana Pass Through the Precambrian of southern Ethiopia? 1,2

3

4

Bisrat Yibas , Uwe W. Reimold , and Carl Anhaeusser . 1

Council for Geoscience, 280 Pretoria Road, Silverton, Pretoria 0001, South Africa; 2 School of Environmental Sciences, University of South Africa, P. O. Box392, Unisa, 003, South Africa([email protected]); 3 Museum für Naturkunde and Humboldt Universität zu, Berlin, Germany; 4 School of Geosciences, Univ. of the Witwatersrand, Private Bag 3, 2050, Johannesburg, South Africa

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he Moyale ophiolite in the Precambrian of Southern Ethiopia is remnant of one of the youngest (~700 Ma old) oceanic basins so far recognized in the Arabo-Nubian Shield of the East African Orogen. It was closed due to oblique continent arc-continent collision at about 660 Ma. Its closure was followed by final terrane accretion, which emplaced the ANS between the continental blocks of east and west Gondwana between 650 and 550 Ma, along arc-continent sutures. The Moyale ophiolitic fold and thrust belt is a transpressive deformational belt, associated with arctype plutonic rocks, dated at ~670 Ma. Its western margin is the N-S trending Roukka Shear Zone, which was strongly reactivated by the transpressive regional D3-4 deformations, the age of which is reasonably constrained by the 580 to 550 Ma granites that were deformed by this transpressive deformation event. The deformational style of the Roukka Shear Zone and its apparent northward continuation, the Wadera Shear Zone bears a strong resemblance to the structural styles of both the Nabitah and Urd-Al Amar zones in the north western part of the Arabian-Nubian Shield. Moreover, the ophiolites of the Urd-Al Amar Nabitah zones have ages (694±8 Ma and 709-750 Ma, respectively, similar to those of the Moyale ophiolite (700±10 Ma). Their estimated times of collision (Nabitah, 720-680 Ma, Urd-Al Amar, 680-640 Ma) are similar to the age of subduction for the Moyale basin at about 670 Ma (SHRIMP U-Pb zircon age for the Moyale granodiorite, although that of the Nabitah Zone is slightly older. One of the strongest arguments by Shackleton (1997) to support that the Nabitah and the Urd-Al Amar deformational belts are major suture zones between East and West Gondwana is the contrasting age results for the terranes on both sides of these zones. Such contrasting age signatures were also obtained to the west and east of the Wadera-Roukka Shear Zone: xenocrystic zircon ages ranging between ~2050 to 1362 Ma were obtained (SHRIMP, zircon) from pan-African granitoids west of the Wadera Shear Zone. All the evidence discussed above strongly suggests that the Moyale-Roukka deformation belt forms a major part of a suture zone between East and West Gondwana. If the interpretation that the Moyale-Wadera Zone is correlative with the Urd-Al Amar Zone is correct (this interpretation is favoured on account of the amphibolite grade of metamorphism and deformation ages and structural style), then it follows that this suture forms an important part of the final collisional suture between East and West Gondwana, which occurred between 670 and 550 Ma. This suture zone, herein referred to as the Urd-Al Amar-Moyale Suture, would separate the juvenile Pan-African crust (partly reworked) to the west from the Palaeo- to Meso - Proterozoic crust to the east.

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Bima Sandstone as A Tectono-Sedimentary Deposition in The West African Craton OPELOYE, Saka Adelayo Applied Geology Department, Federal University of Technology, Akure

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mpact of tectonism is investigated in the Bima Sandstoneas an incipient sedimentary deposit in the intracratonic basinlocated within the Archean Precambrian rocks of Nigeria. It is an extensive alluvial deposit that occupies the entire Benue Trough and Borno Basin. The formation, often multi-story is marked by distinct bed boundaries separating pervading primary structures of cross beds and occasionally, soft sediment structures. Texturally, it is composed of medium grained, poorly-sorted, fine skewed and very leptokurtic, angular edged particles with the frame work classified as Lithic-arkose. The alluvial architecture and stacking patterns depict sedimentations in major depositional settings of fanglomerates of slope deposit, braided and flood plain deposits of fluviatiles and deltaic sedimentation into lake depressions. The deposition is mainly controlled by allogenic factors of climate and tectonism resulting in ten lithofacies, identified on the basis of lithology, grain size and sedimentary structures. Four main lithofacies associations (FA I to FA IV) representing distinctive depositional environments are established. FA I is a conglomeratic facies association representing gravity driven talus and debris flow fan deposits. FA II is a major tabular sandstone facies representing fluvial channel deposits. FA III is deformed soft sediment beds representing rapid sedimentation occasioned by hydrodynamic pressure and FA IV, composed of medium bedded lenticular sandstone which represents lacustrine and ponding environment in the basin axis. A model of high sinuous meandering flow marked by cyclic graded bar and followed by low sinuous braided channel having isolated strips of fine grained sediment is established. NW-SE major azimuth of paleocurrent directions indicate particle provenance from the north central basement.

Lithofacies and depositional environment of Gombe Formation Northern Benue Trough, Nigeria Musa Bappah USMAN1, Yusuf Dabari MAMMAN2, Usman ABUBAKAR1*, Enam OkonOBIOSIO3, Abdulwahab BELLO1, Aliyuda KACHALLA1 1

Department of Geology, Gombe State University, Gombe, Nigeria Department of Geology, Modibbo Adama University of Technology, Yola, Nigeria 3 Department of Geology, Amadu Bello University Zaria, Nigeria Corresponding author: *[email protected]

2

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he Gombe Formation is the topmost sedimentary unit of the Cretaceous Sediments in the Gongola Sub-Basin of the Northern Benue Trough. The formation was differentiated in to threepart/lithofacies: the prodelta facies (lower part), the bedded sandstone facies (middle part), and the red sandstone facies (upper part). Lithofacies analysis was conducted on Gombe Formation exposed around Gombe, Doho, and Malam Sidi in the Gongola Sub-Basin of the Northern Benue Trough, with an objective to interpret palaeodepositional environment and reconstruct the depositional model and facies architecture.Twelve (12) facies were identified on the bases of lithology, grain size, sedimentary structures and degree of bioturbation.These facies constitute five (5) facies association: FA-1, FA-2, FA-3, FA-4 and FA-5.These facies associations were interpreted as braided river, distributary channel,mouth bar, distal and prodelta, and offshore marine respectively.The Facies and facies association interpretation suggest fluvial and tide influence delta. The studied sections are summarized by one facie model, which indicated progradational facies association from braided river to delta mouth deposit and prodelta to offshore marine shale. PAGE


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Sedimentary Geology of the Bima Sandstone, West of Bagge Hills: Implications for Provenance and reservoir characteristics. (Bajoga Sheet 131NE). Isaac OminyiAjigo Department of Applied Geology, Federal University of Technology P.M.B. 704, Akure, Ondo State, Nigeria. Tel: +2348032107038; e-mail: [email protected]; [email protected].

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ault-bounded strata belonging to the Bima Sandstone west of Bagge Hills, (bounded by 0 0 0 0 longitudes 11 20'00''E and 11 23'16''E and latitudes 10 56'43''N and 10 58'53''N), in the Upper Benue Trough, northeastern Nigeria, were mapped and logged. Samples were studied with a view to determining textural and mineralogical characteristics, provenance and palaeoenvironment, so as to develop a depositional history for the rock strata. Field geology revealed the occurrence of three sedimentary formations within the study area in this stratigraphic order: Bima Sandstone, Gongila Formation and Fika Shale. Petrographic studies and sieve analyses of the Bima Sandstone revealed variations within the sequence, some of which are neither regular nor continuous. Interstitial clay content decreases vertically from bottom to top; so also is the colour from grey to brown and then reddish-brown. Grain size, relative sorting, thickness of beds, bioturbation and skewness fluctuate and does not follow any regular pattern from bottom to top and some beds were seen to have repeated occurrence within the sequence. Grain size analyses characterize the sandstones as medium- to coarse-grained, poorly sorted, leptokurtic, positively skewed, randomly burrowed, planar and having a random texture gradient. Depositional environments defined by values of binary plots of skewness versus standard deviation, mean versus standard deviation for samples obtained from the Bima Sandstone of the study area, confirmed by binary plot of skewness versus median for same samples indicate that sediments of the Bima Sandstone was deposited in a continental fluvial paleodepositional environment, characterized by fluctuating energy level, resulting in a random architecture, that was generated during relative sea level fall in the Basin.

Sedimentological and Palaeotemperature Studies using Stable Isotopes on Quaternary Sediments of Lagos Area, Eastern Dahomey Basin, Southwestern Nigeria Dupe EGBEOLA and Olugbenga A. BOBOYE Department of Geology, University of Ibadan, Nigeria-West Africa. E-mail: [email protected]; [email protected]

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he Quaternary sediments of Lagos area was studied using ditch samples retrieved from wells at three locations for provenance, environment of deposition, maturity, age of the sediments and palaeoclimatic changes that prevailed during the deposition.

A total of forty two samples were used for the granulometric analysis, fifteen for heavy minerals and petrographic analysis, nine for palynological analysis, twelve pebbly conglomerates for morphometric studies and mollusc shells for isotopic analysis. The results show medium to very coarse grained, moderately sorted to very poorly sorted, strongly positive skewed to near symmetrical and very platykurtic to extremely leptokurtic indicative of river laid sediments suggesting high to low energy transporting medium. PAGE


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The heavy mineral assemblage is characterized by zircon, tourmaline, rutile, garnet, epidote, staurolite, apatite and sillimanite suggesting igneous and metamorphic provenance. The average ZTR index is 53.9%, indicating texturally immature sediments. Petrographic results show that the most abundant minerals are quartz ranging from 90% to 95%. The QFR ternary plots revealed predominantly super mature quartz arenites. Palynomorphs recovered revealed abundance of mangrove swamp forest species and occurrence of freshwater swamp forest species suggesting a mangrove dominated environment with high influx of freshwater. The sediments were suggested to be of Quaternary period. Pebble morphometric studies revealed littoral setting and the plot of maximum projection sphericity against oblate prolate index suggest fluvial origin. The pebble forms are dominantly compact and compact bladed which further supports fluvial process. Oxygen and carbon isotopic composition of bivalves from Lekki well range from -4.93‰ to -2.94‰ VPDB (mean value of - 4.22‰) and -10.35‰ to-3.71‰ VPDB (mean value of -7.43‰) respectively while Apapa well shell fragments revealed ä18O values of -2.48‰ and -2.19‰ VPDB, ä13C values of 3.27‰ and -1.96‰ VPDB. The results show a positive correlation between oxygen and carbon isotopic composition which suggests that seasonal climate change might influence carbon source to some degree. The estimated formational palaeotemperatures vary from 28.93oC - 40.82oC. Palaeoclimate, morphometry, petrography, bivalves, mollusc, Palynomorphs

Key words:

Geochemistry and Provenance of Shale Units from the Paleocene Ewekoro Formation, Southwestern, Nigeria *

*

**

Oladimeji R. G., Nwegbu A. N., Akaegbobi M. I. And

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Ojo O. J.

*

Nigerian Geological Survey Agency ** Geology Department, University Of Ibadan, Ibadan *** Department of Geology, Federal University Oye-ekiti Contact: [email protected]

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norganic geochemical study of shale units from the Paleocene Ewekoro Formation, Dahomey Basin was carried out to determine the paleo-environmental conditions of deposition, provenance and tectonic setting. Twelve samples were subjected to geochemical analysis involving determination of major, trace and rare earth element composition. The values of chemical index of alteration (CIA), mineralogical index of alteration (MIA) and chemical index of weathering (CIW) obtained from the investigated samples and the ratio of Th/U were used to determine the weathering history and provenance of the samples. The range of values of CIA, MIA and CIW obtained are 60.30-79.21, 20.6-58.42 and 89.9-93.3 respectively, suggesting intermediate to extreme weathering conditions. The values of Th/U ratio is between 4.5 and 6.1 while the calculated values of ICV for the samples are less than 1which indicate intensive weathering at the source and mature sediments. The values of Al2O3 /TiO2 ratio range from 16.39 to 20.2 and this suggests intermediate rocks as probable source of the sediments. All the studied samples fall in the passive margin field in the plot of SiO2 versus K2O/Na2O. The values of Ni/Co in the samples are below 5, suggesting oxidizing environment. The study shows that the shale units of Ewekoro Formation have been subjected to intermediate and extreme weathering processes and deposited under oxidizing paleo-oxygenation condition. It was also inferred from the study that the provenance of the source rock is intermediate and from stable continental margins. Keywords:

Ewekoro, shale, chemical index of alteration, provenance,

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Geochemistry and Provenance Studies of Clastic Sedimentary Rocks from the Cenozoic Agbada Formation, Niger Delta Basin, Southern Nigeria: Implications for Tectonic Environment J. E. Ogala*,1, P. C. Omekeh2, I. M. Akaegbobi3, E. I. Omabere1, O. O. Omo-Irabor4, 1 1 1 1 1 E. P. Ehijene , I. F. Ikechukwu , B. Ekpebabor , A. A. Eruvwedede , E. P. Ekpe 1

Department of Geology, Delta State University, P.M..B.1, Abraka, Nigeria 2 Pioneer-Alfa Petroleum View Estate, Ajah, Lagos, Nigeria 3 Department of Geology, University of Ibadan, Ibadan, Nigeria 4 Department of Earth Sciences, Federal University of Petroleum Resources, P.M.B.1221, Effurun, Nigeria *Corresponding author, e-mail: [email protected]

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he petrography and geochemistry (major, trace and rare earth elements) of 27 sandstone and shale samples from the Eocene-Recent Agbada Formation, southern Nigeria, were studied to decipher their provenance and tectonic setting. Petrographic modal composition revealed that the sandstones are dominated by quartz (on average 95%) with minor amounts of feldspar and rock fragments, suggesting their derivation from nearby basement rocks typical of craton interior sources. Geochemically, the Agbada Formation sandstones are classified as greywacke, litharenite, sublitharenite and quartz arenite. The chemical index of alteration (CIA= 19.6-90.3%) and chemical index of weathering (CIW= 20.0-96.3%) values for these sandstones suggests their high weathering nature. Major oxides composition in the sandstones are dominated by SiO2 (68.97-97.81%); Al2O3 (0.53-14.27%); Fe2O3 (1.03-4.52%); MgO (0.03-1.03%); CaO (0.04-3.18%); K2O (0.06-2.03%) and TiO2 (0.02-1.20%), indicating a high detrital quartz and clay mineral constituents. However, the low concentration of Cr and Ni imply that these sandstones were derived from dominantly felsic source rocks. The Eu/Eu* (0.13-2.6); La/Sc (4.34-10.7); Th/Sc (1.21-4.3); La/Co (0.11-5.35); Th/Co (0.032.15); Th/Cr (0.06-0.25) and Cr/Th (3.28-16.66) ratios support a felsic source for these sandstones. Inferences from tectonic discriminant diagrams and plots of K2O/Na2O versus SiO2 and V versus Sc, indicated a passive margin setting for the sandstones. The geochemical and petrological features revealed that the source area is constrained to the igneous and metamorphic basement complex rocks of the Cameroon- Adamawa highlands and Oban Massif in the southeast and the uplifted Abakaliki Anticlinorium.

Petrology and Geochemistry of Ihugh – Mede Sandstones, Lower Benue Trough, Southeastern Nigeria 1

2

1

Young Ezenwa Obioha , Sikakwe F. , Peter Chidozie Chikezie , Osita C. Okeke, Akunne A. Onunkwo1, Samuel A. Onyekuru1, Julius C. Iwuagwu1, Chikwendu N. Okereke1 1

Department of Geology, School Of Physical Sciences, Federal University Of Technology Owerri, Nigeria E-Mail: [email protected], [email protected]; Phone: +2348038774782, +2348086485661 2 Department of Geology University of Calabar, Calabar Nigeria, E-Mail:

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apping and petrologic studies of rocks of Ihugh-Mede area Northwest Obudu Plateau (sheet 291), Southeastern Nigeria, reveal that sediments, mainly feldspathic sandstones (FSS), arkoses (ASS) and greywackes (GWK), constitute important lithologic units occurring in the area. They unconformably overlie the adjacent basement gneisses, schists, migmatites and amphibolites taught to be their main provenance sources. The FSS and ASS are yellowish gray to whitish in colour, while the GWK shows a dark grey colour. Sieve analysis and plots in the US standard grading charts, show that the FSS and ASS are medium to coarse grained, moderately to well sorted, texturally mature as aquifer materials and petroleum reservoir sands. o Structurally, they strike NNE (0 – 20 ), and dip approximately NW in the general trend of the PAGE


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basement spurs, indicating that their depositions were structurally controlled. The greywackes occur as massive bodies, grading from fines through medium to coarse sands, with numerous sink holes, and about 15% matrix content, and abundant wood fragments, indicating deposition from continental turbidities. Both the feldspathic sandstones and arkoses consist of about 2-5% matrix,79-92% framework elements, and 10-15% pores respectively. The arkoses characteristically shows evidence of lamination and cross bedding, indicating deposition from fluvial continental environment. Petrographic analysis shows that all the sandstones are highly enriched in quartz (76 vol.% in the GWK; 82 vol.% in the ASS; and 94 vol.% in theFSS); with the polycrystalline quartz showing superior abundance over the monocrystalline quartz). Feldspar (mainly plagioclase and orthoclase), constitute 10 – 15vol. % in the ASS and FSS respectively, followed by muscovite which shows value of 0.5 to 2vol.%. the ASS and FSS respectively.. All the sandstones are depleted in lithic fragments, hematite, tourmaline, chlorite and apatite, except the greywackes, which is relatively enriched in lithic fragments and chlorite, corroborating its sub-mature characteristics. Analyses using various discrimination diagrams classify the Mede 1, Mede 2 and the Ihugh sandstones as unimodal, well sorted, mature beach arenites, deposited under minor regressive-transgressive environment. Environment of deposition, Ihugh-Mede, lithology. Obudu Plateau, petrology. provenance, sandstones,

Keywords:

Provenance Studies of Sandstone Facies Near Igbile, Southwestern Nigeria: Petrographic and Geochemical Approach 1

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Ikhane P. R. , Akintola A. I. , Bankole S. I. , Oyinboade Y. T. 1

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1

Department of Earth Sciences, Olabisi Onabanjo University, Ago-Iwoye, Ogun State. [email protected], [email protected] 2 Geosciences Department, University of Lagos, Akoka, Lagos State.

eochemical and petrographic studies were carried out on sandstones exposed near Igbile, Southwestern Nigeria with the aim of deducing their provenance, source area weathering conditions, paleoclimate and tectonic setting.

Ten samples were carefully obtained following geological fieldwork in the study area and were then subjected to petrographic studies, to obtain mineralogical information and inorganic geochemical analyses using Inductively Coupled Plasma- Mass Spectrometry (ICP-MS) to determine the major, trace and rare earth elements concentration in the samples. Results of the petrography revealed that quartz is the most dominant detrital mineral with (74.5%) followed by weathered plagioclase feldspar (5.10 %) and rock fragments (20.4%).The quartz grains are sub-angular to sub-rounded in shape and the sandstones are classified as quartzarenites, sublitharenites and subarkoses based on framework composition of quartz, feldspar and rock fragment plots. This suggests a recycled orogen source for the sandstones and deposition in a humid climate, evidenced by the weathered feldspars. Eleven (11) major, seventeen (17) trace and fourteen (14) rare earth elements were obtained from the geochemical analysis. The major elements values range in concentration from 0.01% - 81.39% with SiO2 being the dominant oxide followed by Al2O3 and Fe2O3 constituting over 95% of the major oxides; K2O, TiO2, Na2O, CaO, MgO and P2O5 made up the remaining 5%. The average ratio of SiO2/Al2O3 valued 4.31 for the sandstone is appreciably high indicating that it has been heavily weathered. The trace elements range in concentration from 0.2ppm-1651.2ppm with Zr being the most dominant element, an indication of orogenic recycling. The rare earth elements range in concentration from 0.01ppm- 163.7ppm with Ce having the highest concentration, depicting that the sandstones were deposited in an oxidizing environment. Also, the PAGE


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trace element relationship illustrated from the spider plot shows chemical coherence and uniformity of the sandstones. The chondrite normalized rare earth elements (REE) plot shows enrichment in the Light REE over the heavy REE for the sediment with strong negative Eu anomaly values between (0.57- 0.69) suggesting a felsic provenance derived from upper continental crust for the sandstones. Conclusively, the sandstone facies were sourced from a felsic igneous to an intermediate igneous origin, deposited in oceanic island arc under humid climatic conditions with an intensely weathered and the source. Keywords:

Provenance, Sandstone, Petrography, Weathered, Inorganic Geochemistry.

Provenance Study of Devonian Shales and Sandstones in the Accraian Series, Southern Ghana Chris Anani*1, Daniel Kwayisi1, Naa A. Agra 1, Daniel K.Asiedu1 1

University of Ghana, School of Physical and Mathematical Sciences, Department of Earth Science, P. O. Box LG 58, Legon-Accra, Ghana *Corresponding Author's email: [email protected]

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he provenance and tectonic setting of the sandstones and shales of the Devonian Accraian series of southern Ghana is discussed for the first time. Modal petrographic analysis on the sandstones suggest a gneissic-granitoid source with some contribution from recycled sedimentary source. Quartz-Feldspar-Lithic fragments (QFL) plots of the sandstones suggest derivation from a recycled orogenic field. The geochemical data show low Al2O3/TiO2 values and trace elements (Cr and Ni) contents suggesting an intermediate to felsic source for the sandstones and intermediate to felsic source with probably, some contribution from mafic sources for the shales. Multi-element plots as well as variation diagram further suggests intermediate - felsic input for sediments of the sandstones and shales. The use of bivariate and discrimination diagrams pointed to multiple tectonic history of the sandstones. The sandstones plotted in the Passive margin (PM) and the Active continental margin (ACM) fields. The shales dominantly plotted in the volcanic island arc (ARC) field with a few straddling within the ACM field. Considering these, multiple point sources of sediments for the Accraian sedimentary rocks are possible. Keywords:

Accraian, Geochemistry, Ghana, Provenance, Sandstone and Shale

Petrography and Geochemical Characteristics of Sandstone Facies from the Eze-Aku Group, Afikpo Synclinorium, Southern Benue Trough Nigeria: Implications for Provenance and Tectonic Settings Ezekiel Obinna Igwe Department of Geology, Ebonyi State University, Abakaliki, Nigeria([email protected])

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ield study, petrography and major oxide based geochemical analysis of the Eze-Aku Sandstone facies outcropping within the basin were utilized in this study. The aim is to provide petrographic classification for the sandstones and interpret the provenance, paleoclimate and tectonic setting of the basin. Field studies show repetitive cycles of sandstones and shales. Four major sandstone facies were identified: (1) Massive, conglomeritic facies, (2) Laminated sandstone facies, (3) Bioturbated sandstone facies, (4) Cross bedded sandstone facies. Ternary plots for framework elements (quartz, feldspar and rock fragments) from petrography of the PAGE


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sandstones indicate the sandstones as arkosic and subarkosic arenites. Tectonic setting discrimination diagrams plotted based on major element oxides revealed continental block provenance dominantly in a passive continental margin. Petrographic and geochemical results indicate large amounts of detritus were derived principally from plutonic igneous rocks with minor contribution from metamorphic source region in a humid climatic conditions and topography ranging from high relief to peneplains, probably from Obudu Plateau, Oban and Cameroon Massifs.

Geological Naming Principles dictate the abandonment of “Benin Basin” and “Dahomey Basin” usage: Is it not Cotonou Basin? Babalola, Olufemi Oladapo Afram-Tech International, Inc., Houston, Texas, USA Butubutu (Nigeria) Ltd., Lagos, Nigeria, and currently also at: Kwara State University, Dept. of Geology & Mineral Sciences, Malete, Kwara State, NIGERIA (Emails: [email protected], [email protected])

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he Dahomey basin of the West African continental margin extending from Ghana to Nigeria was renamed Beninbasin due to a change of name of Dahomey to Benin Republic. Geological naming principles and the absurdity of naming geological features after temporal political entities has yielded no eagernessfor a more suitable name. The geological community could have opted for “Cotonou”, adopted by this author in the late 1980's after the dominant city in the central portion of the basin.None of the major rivers in the basin (Mono, Oueme, and Ogun), sufficiently dominate the basin to have its name indisputably adopted for the basin. A compound name of two cities is an option but certainly not a cumbersome four-city or fourcountry name. In reconsideration of river systems for the basin name, the Oueme River of Benin Republic (in the central portion)and the Ogun River in southwestern Nigeria (the largest single national extent) are the best candidates with the compound name of “Ogun-Oueme” Basinreadily acceptable in Benin Republic and Nigeria where more than three-quarters of the basin area occurs. As the alternatives to “Benin” basin, if “Cotonou” basin does not attract universal acceptability, the most appropriate choices seems either “Cotonou-Badagry” basin or “Ogun-Oueme” basin. Sincethe Ogun and Oueme rivers drain a significant extent of the basin, this riverine name should have preference over the city names. It is time for the geological community in West Africa to put this issue on its agenda for a quick resolution.

Nigerian Gem Quality Sapphire Occurrences: A Review M.B1;Girei A.R2Solomon and S.S3Magaji 1. Nigerian Institute of Mining and Geosciences Jos Nigeria 2. Department of General Studies Nuhu Bamalli Polytechnic Zaria 3. Department of Geology Ahmadu Bello University Zaria, Nigeria Corresponding author's email:[email protected]

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he recent increase in the price of sapphire in the world gemstone market has led to a rise in the activities of artisanal gemstones miners in Nigeria. This development led to the discovery of several sapphire occurrences in various parts of the country especially in the northern parts of the country. Nigeria is now known to be richly endowed with occurrences of world class sapphires crystals. In this review paper, we attempt to synthesize the results of few scattered research and field visits undertaken over the years in those areas were the sapphire occurrences were discovered. This review is necessary in order to provide background information that will serve as an impetus for more PAGE


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detail research that will consequently provide a framework for better exploration and mining of sapphire efforts in the country. Notable areas of sapphire occurrences in Nigeria include; AntahNisama in Kaduna state, Bokkos in Plateau state, Bogoro in Bauchi State; Gunda and Gulde in Yobe State; and Biu in Borno State; Ganye in the Adamawa State; Nguroje (Mambilla) and Karim Lamido in the Taraba State. The sapphire crystals occur within placers and alluvial deposits spatially and temporally associated with intraplate alkaline basaltic flows and plugs located within the country. The weathering of these Cenozoic alkaline intraplate basaltic rocks and subsequent alluvial processes led to the formation of economically viable sapphire deposits. The association between sapphire occurrences and intraplate alkaline basaltic rocks is not restricted to Nigeria but also occur in other parts of the world such as Australia, China, Russia, Cambodia, Thailand, Tasmania, Madagascar and Cameroon. Nigerian sapphire occurrences therefore represent a segment of a global picture of alluvial sapphire deposits whose primary origin is temporally linked to the emplacement of some largely Cenozoic intraplate alkaline basalt-basanite-trachyte-phonolite suites worldwide.

Compositional Characteristics, Genetic Affinity and Economic Significance of the Ironstone Deposit of the Agbaja Formation, Bida Basin, North Central Nigeria 1

Anthony Azubuike ELUEZE , Jubril Izge HASSAN

2

1

Department of Geology, University of Ibadan, Ibadan, Nigeria. Department of Geology, Federal University Lokoja, Lokoja, Nigeria. (e-mail: [email protected])

2

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n the Nupe basin, central Nigeria, the main lithologic units are made up of arenaceous to argillaceous upper Cretaceous sediments, with three lithological units, namely; the basal Lokoja Formation, Patti Formation and the uppermost Agbaja Formation. The Agbaja Formation is composed of ironstones intercalated with siltstones and claystones. Despite the several attempts to ascertain the genesis of the ironstone deposit, there are still some controversies. In order to further ascertain the genetic characterization of the ironstone deposit of the Agbaja Formation, investigation was carried out to understand the field relationships and determine the mineralogical, textural and chemical characteristics of representative samples of the rocks. The ironstones are made up of oolites and pisolites, with the oolites being well sorted, loosely packed spherical ooids within kaolinite matrix, the major mineral assemblages being kaolinite, geothite and hematite ooid. The pisolites are poorly sorted, loosely packed geothite and hemathitepisoids, while the overlying concretionary layer are well sorted detrital grains of silt to clay sizes in a matrix of kaolinite, geothite and hematite. Mineralogical studies show that the ooliticand pisolitic ironstones containgeothite, hematite, maghemite and kaolinite as dominant minerals with quartz, illmenite, rutile, zircon, illite, mica and psilomelane as minor phases. Major elements abundance of the ironstone samples show that they are mainly terrigenous, with about ca.74.08% Fe2O3, In particular, SiO2, Al2O3, P2O5andLOI are having concentration values of ca.3.74%,ca. 6.71%, ca.2.63%,and 11.97% respectively. However, MgO,CaO, K2O, Na2O, S and C all have concentration values below ca. 1%.Similarly, trace element concentration of the ironstone samples show abundance in barium ca.294.70ppm, strontium ca.348.90ppm, vanadium 380.40ppm and zinc 283.10ppm. The Low MgO abundance and positive correlation between Al2O3 and SiO2 suggests kaolinitic precursor for the ironstones. Chemical plot and correlation coefficients of Fe2O3(t) with silica and Al2O3 shows that as iron is added to the kaolinitic precursor, Si and Al are removed from the ironstone deposits reflecting post diagenetic replacement. Discriminant plots of P2O3 with PAGE


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other oxides and trace elements also reflect secondary enrichment for the elevated P2O5 content. Similarly, the Zn-Ni-Co triangular diagram plots towards Zn, indicating an alkaline source. The major element chemistry has shown that the ore body hold strong prospect for exploitation after elimination of alumina and phosphate components. The field, textural and chemical features favours deduction that the ironstone is a product of sedimentation in a more or less fluvial humid environment and subsequent diagenetic and post diagenetic enrichment. Key words:

Agbaja, diagenetic, ironstones, Rare earth elements.

Evaluation of Platinum Group Elements (PGE) Potentials of Ultramafic Rocks of the PaleoproterozoicNyong Series, Southeast Cameroon T. A. Ako,1,2 A. Vishiti3, C. E. Suh2, A. C. Kedia2 1

Department of Geology, Federal University of Technology, Minna, Nigeria ([email protected]) 2 Department of Geology, University of Buea, Cameroon 3 Department of Mining and Extractive Metallurgy, Institute of Science, Engineering and Technology, Cameroon Christian University, Bali, Cameroon

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eta-ultramafic rocks from the PaleoproterozoicNyong Series (SE Cameroon) were investigated in this study. The aim was to study the petrology and evaluate the platinum group elements (PGEs) potentials of these rocks. A layered sequence exposed on a cliff face was mapped. Samples from the various horizons were collected and subsequently analysed in the laboratory for their petrographic and whole rock chemical compositions.The major element composition of the samples, determined by X-ray fluorescence (XRF), indicate that the protolith is ultramafic in nature with SiO2 and MgO contents that range from 38.62 to 44.22 wt % and 21.56 to 35.21 wt %, respectively. This inference is supported by the trace element geochemistry determined by inductively coupled plasma mass spectrometry (ICP-MS) which shows elevated values for Cr, Ni, V, Co and Cu.The latter are typically immobile elements in the primary environment and therefore serve as proxies for the composition of the protolith of these meta-ultramafics. Gold (Au) contents in the samples range from 1.3 517.7 ppb with an average value of 21.9.ppb. Rare earth elements (REEs) data show light rare earth elements (LREEs) enrichment over heavy rare earth elements (HREEs) with variable europium (Eu) anomalies. The principal PGEs identified by a combination of Ni sulphide fire assay, ICP-MS and instrumental neutron activation analysis (INAA) in these rocks are iridium (Ir, 0.9). Uranium Scatter plot with Tio2, and MnO shows a negative inverse correlation however it indicates positive PAGE


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relationship with other variables. Factor analysis shows that Uranium is concentrated in Shale, Phosphate and Lateritic Ironstone. Factors analysis show high loading of 0.9 in component 1, with weak loadings in component 2 and 3. The areas with high concentration of uranium on the spatial distribution map correspond to areas of High Uranium anomaly on the Regional airborne radiometric data. The sediments in the area contains uranium which can be tapped as a non-conventional source. The result of the geochemical analysis correlates well with areas of high Uranium anomaly and geology. Keywords:

Uranium, spectrometer, Factor analysis, correlation, correlation coefficient

Improving Malawi's Mining Sector Through Domestication of African Mining Vision Elyvin Nkhonjera, Young Earth Scientists (YES) Network Africa [email protected]

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n the recent years, mining has become an important issue in Malawi because of its potential to significantly contribute to Malawi's Gross Domestic Product (GDP). It is estimated that mining sector contribution to the GDP grew from 1% by 2001; to about 3% by 2004; and to 10.8% by 2010 as a result of the Kayelekera Uranium Mine. Currently it is less than 1% according to the World Bank 2014 report. However, it is projected that a well-managed mining sector could contribute between 20-30% of Malawi's GDP in the next five years. There is also a consensus that the mining sector has the potential to overtake agriculture as a major source of foreign exchange in the country based on three factors. Firstly, unlike agriculture, the mining sector is resilient to the vagaries of weather and climatic patterns. Secondly, the prices of tobacco, the country's main foreign exchange earner, continue to fall. Thirdly, existing data shows that Malawi has significant potential reserves of various minerals such as Uranium, Gemstones, Coal, Rare Earth, Niobium, Bauxite, as well as Oil and Gas in Lake Malawi. However the sector still faces a number of key challenges. The Tilitonse Political economy Analysis in Mining report revealed 4 key issues affecting the mining sector not to realize its potential. These issues include weak and out dated legislative, policy and institutional frameworks; weak and fragmented role of civil society organizations; lack of a framework for stakeholder engagement at community level; and absence of robust revenue management and transparency mechanisms. The Africa Mining Vision (AMV) adopted in February 2009 by the African Union Assembly of Heads of State and Government as the key continental framework to promote mineral resource based development and structural transformation on the continent, seeks to foster a “transparent, equitable and optimal exploitation of mineral resources to underpin broad-based sustainable growth and socio-economic development.” The Government of Malawi through the Ministry of Natural Resources, Energy and Mining (MNREM ) in collaboration with the United Nations Economic Commission for Africa (UNECA)and in particular, the Africa Minerals Development Centre (AMDC), initiated the process of domesticating the AMV in Malawi. Therefore this paper aims at assessing the way in which the domestication of the African Mining Vision will improve Malawi's Mining Sector and promote sustainable development of the country.

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Mineralogical and Geochemical Evolution of Duthuni Kaolins Lawrence Diko1, Georges Ekosse2 and Jason Ogola3 1

Geology Division, University of Limpopo, Private Bag x1106, Sovenga, 0727: [email protected] Directorate of Research and Innovation, University of Venda, Private Bag X5050, Thohoyandou, Limpopo 3 School of Environmental Sciences, University of Venda

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his study elucidates on weathering intensity, trends and possible source rock compositions of Duthuni Kaolins based on quantitative estimation of the chemical index of alteration (CIA), SiO2:Al2O3 and Fe2O3:TiO2 ratios, and interpretations of geochemical discriminant plots. Results suggests moderate to advanced argillic alterations, accompanied by differential redox +3 +4 conditions associated with relative immobility of Fe over Ti across the studied profile. A ferromagnesian rich parent material is proposed for the kaolin.

Size Distribution and Heavy Mineral Pattern in Some Streams Around Egbe, Southwestern Nigeria. * Joseph Ayofe Aderogbin, Chigozie Eugene , UBA and Olukayode Adeyinka Falana Department of Earth Sciences, Ajayi Crowther University, Oyo. Nigeria. [email protected]

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he composition of heavy minerals in sediment is a reflection of the type of parent-rocks within a catchment area. Type, distribution and physiographic conditions of heavy mineral in sediments defines the transport history from source to basins of deposition. The nature, type, compositional variation and textural differences of the minerals are parameters needed for o o dependable provenance study. The study area is located in Egbe, within Longitude 05 31' and 05 43' o o and Latitude 08 03' and 08 16 ' of the Southwestern Basement Complex of Nigeria. Fifteen (15) stream sediment samples were collected at suitable points along river channels, air dried at room temperature and sieved. The heavy minerals were separated using bromo form and the results of grain size analysis statistical treated to determine the graphic mean, sorting, skewness and the kurtosis. Result show the graphic mean ranging between 0.67 (coarse sand) to 2.49 (fine sand) , sorting rages from 0.9 to 1.05 and average 0.6 indicating a moderately to poorly sorted sediment. The skewness is between 0.75 or strongly fine skewed to -0.10 and Kurtosis value ranges from 0.87 to 1.88. Heavy mineral identified in the sediments includes tourmaline, epidote, rutile, zircon, kyanite , staurolite, garnet and zeolite indicating a mixed source. The ZTR index values range from 16.0%22.0% and this shows that the sediments are immature to sub-mature sediments. Some of the heavy minerals are angular to sub-angular suggesting that the sediments did not traveled far from the source.

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Geochemical and Spectral Characterization of Hydrothermal Alteration Facies at the Epithermal Gold Mineralization at Rodalquikar, Spain Kamina Chororoka African Minerals and Geosciences centre ([email protected])

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he present study aims to test whether direct field data of major and trace elements can be used in combination with mineralogical IR information for the exploration of the epithermal gold deposits.

89 rock-samples were available for portable XRF and ASD spectral measurements, these samples were collected in 2004 along two perpendicular traverses by ITC students over the Rodalquilar epithermal gold deposit. Rodalquilar Gold Mine forms part of the Cabo de Gata National Park area which is located close to the coast in the Almeria Province in the south-eastern part of Spain. The total area covered in this study is approximately 56 km2. Element concentrations of major and trace elements together with mineralogical information were used to study the lithological differences and alteration style/intensity on the study area. Positive correlations between SiO2, Al2O3, TiO2, Zr, and Sr are observed which is linked to the lithological association, also a positive correlation is observed between As and S which is associated with mineralization. Zr and Ti are the most suitable elements to discriminate andesites and rhyolites lithologies. The Silicification and Hashigushi Indices calculated from the whole rock geochemistry, proved to be most effective in delineating argillic-advanced argillic alteration styles for the epithermal deposits. Kaolinite crystallinity and mineral chemistry (Al-OH position and depth) indicate the potential application of reflectance spectroscopy in the characterizing alteration and elements associations within the Rodalquilar. Results indicate that by using data obtained with a portable XRF and a NIR field spectrometer, it is possible to differentiate between lithologies, different alteration styles and intensities. In addition the Zr- Ti relationship can be used to characterize different volcanic lithologies in an epithermal gold environment. Setting.

Electrical Resistivity Prospecting for Groundwater in the South Eastern part of Ilorin Metropolis, Southwestern Nigeria. *Talabi, A. O., Ojo O. F., Afolagboye L. O., Ajayi C. A. and Ajisafe Y. C. Department of Geology, Ekiti State University, P. M. B. 5363, Ado-Ekiti. *([email protected])

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he South Eastern part of Ilorin is located on Basement terrain where occurrence of groundwater is erratic necessitating prospecting for groundwater employing sound scientific approach. Electrical Resistivity Prospecting for Groundwater was conducted in the area with the aim of locating a suitable point for sitting of borehole. A total of forty two (42) sounding points were occupied using Schlumberger array with maximum spread of 150m. Acquired data was subjected to partial curve matching and computer iteration. Geo-electric sections were obtained using Microsoft Office Excel software. The interpreted data revealed five different subsurface lithologic units namely; Topsoil/sandy layer, lateritic clay, weathered basement, fractured basement and fresh basement. The topsoil/sandy layer PAGE


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Determination of Porous Zones using Vertical Electrical Sounding Data from Basement Rocks of Kwal, Kanke, North-Central Nigeria J. A. Bulus*, M. P. Goyit, and S. S. Daku. Department of Geology University of Jos, Plateau State, Nigeria *E- mail address for correspondence: [email protected]

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his work was undertaken to study the porous zones of Kwal and its environs, Forty (40) vertical electrical sounding data using the schlumberger configuration with current electrode with a maximum electrode spacing of AB/2 = 125m were carried out in the study area. The field data were smoothens and interpreted using computer software (Win Resistinversion) in order to estimate the porosity and determine the porous zones. The interpreted results revealed three geoelectric layers with varying thickness and levels of weathering. The three geo-electric layers were interpreted to be clayey sand, weathered basement with resistivity values ranging between 18.9 to 498.2Ùm indicating porous zones due to secondary porosity or water content while the third layer is interpreted to be fresh basement, this layer revealed high resistivity values that ranges between 521.6Ùm to 6148.2Ùm. Key words:

Porosity, Weathered Basement, Sounding, Resistivity, and Geo-electric layer

Evaluation of Groundwater Resource Potential in Rural Part of Northcentral Nigeria Using Vertical Electrical Resistivity Method Ibrahim K. O. 1, 2 and Gomo M.1 Institute for Groundwater Studies, University of the Free State, Bloemfontein, Republic of South Africa 1 Department of Geology and Mineral Sciences, Faculty of Physical Sciences, University of Ilorin, P.M.B.1515, Ilorin, Kwara State, Nigeria 2 Corresponding email: [email protected]

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resently, the reliability of water on shallow hand dug wells especially in the rural area of developing countries have proven to be grossly insufficient in meeting the increase in demand by the people for domestic and agricultural uses, therefore, there is urgent need to search for deep underground aquifer by sinking of borehole. A study of groundwater potential in the rural part of Northcentral Nigeria was carried out using Vertical Electrical Sounding (VES). The VES data was generated from twenty (20) locations in the study area and sounding data was later processed and analyzed using IPI2 WIN software. The underlying geo-electric sections comprises of top soil, laterites, weathered basement, fractured basement and fresh basement. The top soil have resistivity and thickness ranges between 44.1- 862? m and 0.5 – 3.52m, second layer which is laterites possess resistivity and thickness between 16.3 - 2001 ? m and 0.62 – 10.3m, third layer is weathered basement having resistivity and thickness ranges from 11.0 – 755 ? m and 3.1 – 52.0m while the fourth layer considered as fractured basement has resistivity and thickness between 93.1 - 3247 ? m and 14.8 – 71.1m and final layer is fresh basement which possess resistivity ranges between 73.7 – 8444 ? m. The interpretation from the resistivity log of regolith rocks shows different curve types which include HA, HKH, QH, H and A – type curves. About 55% of the regolith in the area possesses aquifer potential value of 10.5 which shows optimum weathering and groundwater potential, therefore, any future borehole in this area should be sited in locations 3, 4, 8, 9, 10, 12, 13, 14, 16, 18 and 20. Kew words: Groundwater potential, Vertical Electrical Sounding, Schlumberger Array, IPI2 WIN Software, Geo-electric section. PAGE


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Formation Evaluation of Deep Water Reservoirs of Lower Cretaceous Sequences of the Central Bredasdorb Basin, Offshore South Africa 1

1

Tarig Hammad Hussein and Mimonitu Opuwari * Petroleum Geology unit, Earth science department, University of the Western Cape South Africa Corresponding author: *Mimonitu Opuwari ([email protected])

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he main objective of the study is to enhance the evaluation of subsurface reservoirs by improving the prediction of Petrophysical parameters through the integration of wireline logs and core measurements. The deep water environment sedimentation of the area took place with low oxygen levels due to poor circulation and sediments consists predominantly of alluvial and channel fluvial deposits. Four distinct lithofacies (A, B, C, and D) were identified and subsequently used as an input parameter of an artificial neural network to for facies predictions. Results reveal facies A and B as the best reservoir quality rocks. An average field grain density of 3 3 2.66g/cm and fluid density of 0.79g/cm obtained from core was used for density model porosity determination. Water saturation was estimated based on the Indonesian model. Six hydraulic flow units were recognized and used for permeability predictions. Permeability prediction from flow units was more reliable than that of porosity-permeability relationship. The cut-off parameters used for identification of net pay are; volume of shale 35%, porosity 7%, water saturation 60%, and permeability 0.1mD.The gross thickness of reservoirs ranges from 4.83m to 41.07m and net pay intervals from 9.21m to 29.59m.

Geoelectric Resistivity Imaging for Assessing Crystalline Aquifers' Potential: A Case Study of Textile Awedele, Ado Ekiti, Nigeria. Olubukola Ogungbade1, Philips Aizebeokhai1, Kehinde Oyeyemi1, 2 1 Adeolu Aderoju and Emmanuel Ekechukwu 1

Department of Applied Geophysics, Covenant University, Ota, Nigeria ([email protected]) 2 Dextol Global Geophysicals, Lagos.

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quifer delineation is key to any hydro-geophysical exploration; it becomes more burgeoning to professionals in dynamic locations where there are variations in the possible aquiferous zones. A basement complex terrain has been considered for this research work with the aim of delineating possible weathered formations that could bear water and fracture zones in the choice location. Electrical resistivity technique was employed in this study, thirty (30) Vertical Electrical Sounding (VES) was carried out in the study location using Schlumberger electrode configuration. Also, Electrical Imaging using Dipole-Dipole Electrode array was employed along four traverses. The acquired data was interpreted to derive the geoelectric parameters which are known to be of hydrogeologic relevance. The interpretation results were used to generate maps (weathered/aquiferous layer resistivity map, weathered/aquiferous layer thickness map, basement topography map and hydraulic parameters). The maps were interpreted individually by identifying geoelectric and hydraulic parameters favourable to groundwater occurrence. The results reveal that the area has four geoelectric layers which are; top soil, lateritic soil, weathered basement and fractured or fresh basement. This research work has enabled us to understand the geologic settings and the groundwater potential of the location, this knowledge could as well serve as a guide for further drilling operations in the area.

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Geophysical and Hydrogeological Investigation of Groundwater Challenge around Iragbiji and Environs, Osun State, Nigeria 1

Adeolu O. Ojo and2Oluwafemi J. Akinlabi

1,2

Department of Geological Sciences, Osun State University, Osogbo, Nigeria (1Email: [email protected])

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ydrogeophysical and geological studies were carried out around Iragbiji and its environs, Osun State, Nigeria using an integrated approach that combines the use of electrical resistivity method with flow direction determination. The aim of the project was to investigate the groundwater challenge in communities around Iragbiji and its environs despite their close proximity. Nine (9) vertical electric soundings were carried out across the communities all of which are separated by short distances. Forty eight (48) hand dug wells were selected in the study area for the flow direction determination. Iteration and interpretation was done using the IPI2Win software while Surfer 12 used to generate a 2D isopach map, pseudo-section, 3D aquifer transverse resistance map, overburden anisotropic coefficient map. Well data were used to generate a 3D flow direction map of the study area. The result showed that the area is underlain by granite gneiss that exhibit shallow fracture around Iragbiji and Ororuwo located at the North western part of the study area while there are no shallow fracture in the eastern part of the area where communities such as Ada and Aagba are located. This accounts for the low groundwater potential in these two communities. Investigation of the flow direction reveals that the groundwater flow from east to west, an indication of a gaining stream at Iragbiji where River Ogun drains all the available water. Six geoelectric layer delineated from the vertical electric sounding reveals lithology that range from clayey, sandy, lateritic layers to weathered, fractured and fresh basement.

Hydrogeologic Significance of Geoelectric Characteristics in Borehole Siting in Ajaokuta, Southwestern Nigeria. 1

Fatoba J.O,1Aroyehun M.T, 1Igboama W. N and 1Hammed O.S 1

Department of Geophysics, Federal University, P.M.B 373, Oye-Ekiti. E-mail: [email protected]

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he location of gas turbine power plant at Ajaokuta, Kogi state has drastically increased the growing population of the area; the existing surface water facilities is to be complemented by groundwater resources in order to meet the water demand of the people. This study is aimed in determining the geoelectric sequence of the area, overburden thickness, aquifer geoelectric characteristics, nature and topograph of the bedrock for siting and drilling productive borehole. Horizontal resistivity profiling was conducted at eight (8) traverses with station separation of 30m using wenner array. The locations of lowest apparent resistivity values were occupied for vertical electrical sounding. Twenty five (25) sounding locations were occupied with ab/2 ranges from 1m to100m. The data were acquired using PASI digital resistivity meter(16 GL). The data were presented inform of sounding curves and interpreted by partial curve matching and 1D forward modelling using Win Resist software. The results of the interpretation were used to generate two (2)geoelectric sections relating the VES together. The geoelectric sections revealed four major geoelectric layers which are topsoil weathered basement, partly weathered basement and fresh basement. The topsoil has resistivity value varies from 6 ohm-m to 30 ohm-m and thickness of between ----------to-----------------------). The weathered basement has resistivity values ranges from PAGE


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16 ohm-m to 250 ohm-m and its thickness is of between 10m to 55m. Partly weathered layer has resistivity value of 250 ohm-m and only observed at VES3. The fresh basement has resistivity value varies from 154 ohm-m to 30,000 ohm-m. The major aquifer is the weathered or partly weathered basement. Base on the results, one tested borehole (VES9) and two (2) observatory wells (VES 5 and 4) were drilled. There was significant correlation between the geoelectric sections and the borehole logs. The pumping test analysis conducted on the wells revealed a yield of 25m3/hr with recovery rate of 75%.

Mining of Geophysical Data to Develop Groundwater Conceptual Model in a Basement Complex Environment of Southwestern Nigeria. 1

K. A. N. Adiat and A. J. Osifila 1

1

Federal University of Technology, Akure, Nigeria. ([email protected] ; +2348038670332)

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his study applied the multi criteria decision analysis in the context of the analytical hierarchy process to subsurface resistivity data acquired from Ijebu-jesa town, Osun state to achieve an unbiased integration of several parameters in the order of their hydrogeologic importance to consequently produce a groundwater conceptual model of the area. The coefficient of anisotropy, aquifer resistivity, aquifer thickness, overburden thickness and overburden resistivity were the parameters derived from the results of the interpretation of resistivity sounding data obtained from the study area. These parameters were the main subsurface factors controlling the flow and accumulation of groundwater resources in the area. Each parameter was assigned appropriate weight based on Saaty's nine-point scale and the weights were normalized through the Analytic Hierarchy Process (AHP). The attainment of the consistency ratio of 0.08 (i.e. less than 1) established that the judgments were consistent and unbiased. The groundwater conceptual model of the area was produced from the rating of these parameters and from the Groundwater Potential Index (GWPI) model equation developed. The conceptual model classified the groundwater potential of the study area into very low, very low - low, low - medium, medium - high and high - very high regions. The very low – low and low – medium accounted for about 98% of the total area. The result obtained is typical of groundwater potential in a typical basement complex. The results obtained from this study established that the groundwater conceptual model produced from the GWPI obtained from the application of multi criteria decision analysis to subsurface factors is accurate and reliable. It has also proven the ability of the methodology adopted as a good decision making tool in the presence of two or more conflicting criteria. This ability makes it a useful tool that can be adopted in the groundwater prediction domain.

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Assessment of Groundwater Suitability for Domestic and Irrigational Uses in Kano Municipal Tahir A. G.1, Garba M. L.2 and 3Garba I. 1,3

Department of Geology, Kano University of Science and Technology Wudil, Nigeria. 2 Department of Geology, Ahmadu Bello University Zaria, Nigeria. (E-mail of corresponding author; [email protected])

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he study tries to assess the groundwater suitability for both domestic and irrigation uses in Kano metropolis. Ten groundwater samples were collected, and at each sampling point one was acidified with few drops of HNO3. Physical parameters like PH, Temperature, Total Dissolved Solids (TDS), and Conductivity were measured directly insitu of sampling points using Mi 806 (4 in 1) combined meter. The water samples analysed when compared with WHO (2003 and 2011) and SON (2007) standards were mostly within the permissible limits. However concentration of heavy metals like Pb (0.070-0.121mg/l with average value of 0.0946 mg/l) and Cd (0.005-0.011mg/l with average value of 0.007 mg/l) above maximum permissible limit of (0.01 mg/l) and (0.003mg/l) respectively of WHO 2011, in many samples analysed made the groundwater to be objectionable for drinking. Based on the interpretation of the data using Aqua Chem software; the Wilcox diagram was plotted using conductivity values of the samples obtained during the insitu measurements of physical parameters from the study area. The Salinity Hazard was classified and about 60% of the samples are within C2 category; which are generally regarded to be good for irrigation.

Integrated Geophysical Investigation of a Proposed Weir across a spring at Wadamts Polytechnic, Itaolorun, Southwestern Nigeria Elijah Abejoye, Gregory Omosuyi Department of Applied Geophysics, Federal University of Technology Akure, Ondo State, Nigeria. E-mail address: [email protected], Contact: +2348033143400

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ntegrated geophysical investigation involving Very Low Frequency (VLF) Electromagnetic, Magnetic and Electrical Resistivity methods was conducted across a spring channel in the proposed Wadamts Polytechnic Itaolorun-Idanre, Ondo, Southwestern, Nigeria in order to locate the best axis for a proposed weir across the spring channel. Two traverses each with 100 m long, perpendicular to the spring channel and separation of 50 m each running in the N-S direction were occupied. Geophysical measurements were taken at 5 m interval along each traverse. The Very Low Frequency Electromagnetic (VLF-EM), Magnetic and Electrical Resistivity methods were acquired using Abem Wadi, GEM Proton Precession Magnetometer and R50 DC resistivity meter equipment respectively. The VLF-EM profile and KH pseudo-section shows areas of high conductivity on traverse 1, which are interpreted as fractured zones. On traverse 2, the VLF-EM profile and KH pseudo-section shows conductive medium interpreted as clay patches. The ground magnetic relative intensity range from 432 to 12146 nT with relatively high and low distribution, this suggesting the thin overburden overlying the fractured basement rock along traverse 1 and the competent basement rock along traverse 2. The 2-D Electrical imaging delineated the topmost layer, weathered layer, fractured basement and the fresh basement rock. The thickness of the topmost layer and the weathered layer range from 2.5 to 4.5 m. The weathered layers have resistivity value of 180 to 650 ohm meter. The fractured basement along traverse 1 has resistivity range of 1500 to 4700 ohm meter and the fresh basement have resistivity range of 4000 to 27000 ohm meter. From the geophysical interpretation, the study area is characterized by thin overburden, a fractured basement rock and a fresh basement rock both closer to the surface along traverse 1 and 2 respectively. Hence, the underlying geology along traverse 2 is competent and suitable for the proposed weir and the best axis for the weir is traverse two. Keywords:

VLF-EM, Magnetic, Electrical Resistivity, Weir, Overburden, Fractured basement, Fresh basement PAGE


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Prediction of Groundwater Column in Basement Complex Terrain using Artificial Neural Network K. A. N. Adiat1 and O. F. Ajayi 1 1

Federal University of Technology, Akure, Nigeria. ([email protected] ; +2348038670332)

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he relationship between geoelectric parameters and groundwater column has not been fully understood quantitatively. This is worrisome in the basement complex terrain where these parameters are highly localized. In this study, an attempt was made to predict groundwater column using Artificial Neural Network (ANN) technique that can offer a nonparametric approach in modelling with higher reliability and precision. The ANN technique was applied to geoelectric parameters derived from the results of the interpretation of fifty one Vertical Electrical Sounding (VES) data acquired from the study area. The parameter values so obtained were input parameters used for the training and validation of the ANN. These parameters were the overburden thickness, aquifer thickness, overburden resistivity, aquifer resistivity and coefficient of anisotropy. The results obtained were used to develop groundwater column prediction model. The model was evaluated using two performance criteria namely; Mean Squared Error (MSE) and Regression coefficient (R). The results of the validation showed less mean square error (MSE) of 0.0014286 and the high regression coefficient (R) of 0.98731. This indicates that ANN can be used to predict groundwater column in a basement complex terrain with reasonably good accuracy. The ANN model achieved high predictive accuracy.

Co2- Water-Rock Interaction: Implication for Natural CO2 Analogue in the Wonchi System; Ethiopia. Shube H.1 and Kebede S.2 1

Adama Science and Technology University, Applied Geology Department, [email protected] 2 Addis Ababa University, School of Earth Sciences, P. O. Box: 1176, [email protected]

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sotopic and geochemical data are used to study the CO2-water-rock interaction of ground waters in the Wonchi System. Geochemical data from thermal and hypothermal groundwaters are classified by Q-mode hierarchical cluster analysis in to objective groups in order to identify ground waters that have the same hydrogeological and chemical nature so that to conduct inverse geochemical modeling. Environmental Isotopic data of ä18O and ä2H are used to investigate the Wonchi Crater Lake and groundwater hydraulic interconnection. The ä13C isotope is used to analyze Co2-water-rock interaction and source of Co2 in groundwaters of the Wonchi system. Hydrogeochemical evolution of ground waters of the study area is highly influenced by two regional structures like YTVL and Ambo-Wonchi-Butajira faults that cut across this region. Thermal and gaseous ground waters of the study area are particularly aligned along these structures. Stable isotope data indicates that thermal and gaseous ground waters are depleted in ä18O except in Wonchi area ground waters that shows ä18O enrichment due to hydraulic connection with Lake Wonchi. The CO2 influx to ground waters of the area is due to the deep seated faults that bring this gas from deep source of metamorphic decarbonation or mantle gas origin. The source of CO2 gas is also 13 suggested by using ä C isotope that indicates high values are in thermal and gaseous mineral waters of the region. The effect of the influx of CO2 to ground waters of these regions plays a major role in CO2-water-rock-interaction to be significant and silicate hydrolysis like dissolution and precipitation of silicate minerals during ground water chemical evolution. Trace element mobility (i.e. Sr, Ba, Mn, Fe and Al) is observed in thermal and gaseous ground waters due to strong CO2water-rock interaction. PAGE


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Effects of Alau Dam on Irrigation Farming in Jere Local Government Area of Borno State 1

2

1

1

Mustapha I. , El sadiq M.B. , Kyari Z. andBunu A . 1

Department of Agricultural Technology, Ramat polytechnic Maiduguri, Borno State. 2 Borno State Rural Water Supply and Sanitation Agency.

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his aim of the study was to investigate the significance of Alau dam on irrigation farming, the major crops grown and the effects of Alau dam to the residence of Jere Local Government area of Borno state. Random sampling was used to select (100) respondents and used for the study. Data were analyzed using descriptive statistics such as frequency and percentages. Based on their socio-economic characteristics 53% of the respondents were within the age of 15-35 years. The result showed that majority of the respondents were male 84% and their marital status 75% were married most of the respondents attained informal education and most of the respondents indicated that their occupation is farming and about 90% of their water source used for farming activities was from Alau dam. The findings also indicated that most farmers (50%) cultivated onions. Major problem faced was flood which greatly reduced their yield. Government should provide irrigation facilities to the farmers in order to achieve food security. Key words:

Alau, Irrigation, Farming

Management of Mine Water and AMD Challenges using River Water Catchment Area and Geo-environmental Provinces Approach, South Africa 1,3

1

1

2

Bisrat Yibas , Robert Netshitungulwana , Obed Novhe , Paul Oberholster , Haile Mengistu1, Emanuel Sakala1, Abraham Thomas1, and Janine Cole1. 1

Council for Geoscience, 280 Pretoria Rd, Silverton, Pretoria 0001, South Africa ([email protected]), 2 CSIR, Natural Ressources and Environnement, PO Box 395, Pretoria, 0001, South Africa. 3 School of Environmental Sciences, University of South Africa, P.O. Box 392, Unisa, 003, South Africa.

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national project was conducted aimed at assessing, mapping, and ranking of mine-polluted areas with the view to rehabilitation / remediation in a systematic and holistic manner.

The investigation has been undertaken on a catchment-by-catchment approach prioritized on the basis of geo-environmental provinces. The impact due to mining most severely affects the water resources of the country, the magnitude and severity of which ultimately dictate the well-being of the other environmental sub-systems such as the fauna and flora ecosystems. Mine pollution hotspots were identified and ranked using a multi-disciplinary pollution assessment approach based on water and sediment geochemistry, hydrology, hydrogeology, the current and potential status of acid mine drainage of mining infrastructures, ecotoxicology, remote sensing, and geophysics. Using this approach, a number of pollution hotspots and associated pathways and pollution sources have been identified and presented in the form of catchment-scale pollution maps for eight primary river catchment areas which cover almost all of the geo-environmental provinces of the country. This in turn was compiled to generate a national mine pollution atlas for the country. Based on the ranking of the hotspots, pilot-scale restorative projects are currently being undertaken. The methods and results of the multi-disciplinary catchment-scale mine pollution mapping conducted in the Olifants and Inkomati-Crocodile primary river catchments will be presented briefly in this paper to demonstrate the effectiveness of the approach. PAGE


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The results of this study demonstrate the benefits of a multi-disciplinary approach for the assessment and ranking of mine pollution hotspots, and its potential use in identifying pollution sources faster and cheaper than the conventional mine area approach, especially for large catchments where mining activities are widespread, are of heterogeneous commodities, and where there are many decades of mine legacy. Keywords:

Geo-environment, catchment, mine pollution, hotspot, mine pollution influence area.

Petrology and Geochemical Characteristics of Precambrian Basement Complex Rocks in the South-Eastern Most Part of Wonaka Schist Belt, North-Western Nigeria. 1

1

1

2

3

Amuda A. K. , Danbatta U. A. , Najime T. , Ogunleye P. O. , Okunlola O. A. , 4 1 5 1 Salau S. L. , Magaji S. S. , Andongma W. T. , and Elatikpo S. M. 1

Department of Geology, Ahmadu Bello University, Zaria, Kaduna State, Nigeria. [email protected] 2 Centre for Enersy Research and Training, Ahmadu Bello University, Zaria, Kaduna State, Nigeria. 3 Department of Geology, University of Ibadan, Ibadan, Oyo State, Nigeria. 4 Nigeria Mining Cadastre Office, Ministry of Mines and Steel Development, Abuja. Nigeria 5 Kano State University of Science and Technology, Wudil, Kano State.

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he Precambrian basement complex rocks in the study area mainly include the gneisses, metasediments, granite intrusions and dykes of aplite and pegmatite. The granitic rocks are generally felsic containing modal feldspars and normative corundum as well as normative hypersthene. Anactectic melting is suggested due to presence of ptygmatic folding in banded gneiss, folded gneissose foliation and numerous quartzofeldspathic veins. Geochemically, the granitic rocks are mainly magnesian, calc-alkaline, strongly peraluminius and dominantly syn-collisional. The mineralogy coupled with variation in mobility of alkali elements K and Na confirms low grade metamorphism for the metasediments (greenschist facies) and low to medium grade for the gneisses (greenschist to lower amphibolite facies). The gneisses are mainly of igneous parentage. The granitic rocks have granitic to granodioritic composition related to granite that originated from magma enriched in alumina relative to alkalis. The rocks generally resemble those in other parts of the Precambrian basement complex in Nigeria with respect to their field characteristics, mineralogy, and to some extent their magnesian character and peraluminous nature. Paleoweathering estimates for the metasediments point to relatively moderate to intense chemical weathering of the sedimentary source rocks that are immature.

An Update on the Tectonomagmatic Origin of the Igneous Rocks in the Lower Benue Rift Southeastern Nigeria. 1

Smart C. Obiora, and 2Anthony Chukwu

1

Department of Geology, University of Nigeria Nsukka ([email protected]; [email protected]) 2 Department of Geology, Ebonyi State University, Abakaliki, Nigeria. ([email protected]; [email protected])

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his work presents updates on the tectonomagmatic origin of igneous rocks in the lower Benue rift based on recent available geochemical (major, trace and rare earth elements) data. The igneous rocks occur as volcanic and sub-volcanic rocks: basalts and basaltic sills, pyroclastic rocks (tuffs and lapilli tuff), trachytes, trachybasalts, gabbros (stocks), dolerite sills and dioritic rocks (stocks). The rocks were emplaced within folded sedimentary sequence consisting mostly of shales, and subordinate sandstones and siltstone and carbonate rocks of Asu-River Group and Eze-Aku PAGE


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Formation. Although most of the rocks are moderately to highly altered, with the pyroclastic rocks showing higher effects of alteration (LOI 3 to 22 %), some incompatible and immobile elements (Y, Zr, Hf, Ti, Nb, Ta, La and Ta) and less altered rocks with LOI < 2% show that the rocks were derived from mantle enriched source and HIMU signatures. The high ratios of (La/Yb)N 4.40 to 31.55 in the basic rocks and 23.59 to 135.35 in the trachytic rocks show predominantly alkaline affinity with sparse tholeiites and presence of garnets in the source region. The rocks were formed by plume uprising in a within-plate setting of intra-continental rift system similar to the East African rift. The magnesium number (mg#) and differences of the Spidergrams and rare earth patterns indicate that the rocks are heterogenous source. The depletion of K, P, Th and Rb and formation of calcites and sericites in the rocks mostly in altered samples in spidergrams show mobilization probably by aqueous fluid during low-grade metamorphic alteration. Keywords:

Volcanic and sub-volcanic rocks, alteration, immobile elements, HIMU signatures, within-plate, lower Benue rift.

Four-Stage of Sea-Floor Spreading & Oceanic Crust Maturity in the Plate Tectonic Cycle, from Continental Breakup to Subduction Initiation Babalola Olufemi Oladapo A fram-Tech International, Inc., Houston, Texas, USA Butubutu (Nigeria) Ltd., Lagos, Nigeria, and currently also at: Kwara State University, Dept. of Geology & Mineral Sciences, Malete, Kwara State, NIGERIA (Emails: [email protected], [email protected])

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lobal study of the Sea-Floor Spreading and associated Oceanic Crust permit the identification of four major stages of maturity. These four stages, Immature, Youthful, Mature and Overmature, cover the Plate Tectonic Cycle from the initiation of sea-floor spreading between intra-continental triple junction to the eventual initiation of subduction leading to the destruction of oceanic crust by mantle consumption. In the initial Immature stage of Sea-Floor Spreading/Oceanic Crust tectonic maturity, the spreading centers where new oceanic crust are created consists of unconnected spreading centers and continental blocks stranded amidst oceanic crust. The second, Youthful stage of tectonic maturity consists of connected spreading centers but these are short, highly-segmented oceanic ridges connected by long Fracture Zones. In a triple junction system, there is usually a rift arm where sea floor spreading was not successfully initiated but the rift is still somewhat active. In the third, Mature stage of tectonic maturity, the Spreading Centers are by now connected by long oceanic ridges linked by short Fracture Zones. The final Over-Mature stage of tectonic maturity consist of oceanic crust has now been transported very far from the spreading center and has with time cooled down so much that it has subsided to depths where it is beginning to sink into the upper mantle/aesthenosphere and initiating subduction. The recognition of stages of tectonic maturity helps in the classification of sea-floor spreading and associated oceanic crust from the feature identified in each terrain. Additional subsidiary stages of tectonic maturity can be identified from further study.

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Geological Mapping of Igbara-Oke and Owena Area South Western, Nigeria 1

1

M. D. Ayanwola , O. A. Bamisaiye 1

Department of Applied Geology, Federal University Of Technology, Akure, Nigeria Email:[email protected]

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etailed geological mapping incorporated with interpreted aeromagnetic data of the IgbaraOke and Owena area of south-western Nigeria provides a new insight into the lithology and structures in the area. The interpreted, derivatives maps such as Total Horizontal Derivatives (THD), Second Vertical Derivative (SVD), Regional Magnetic Anomaly (RMA) were analysed for lithology delineation. For structural delineation, 3D Eulerdecon volution, Source Edge Detector (SED) and some derivative maps were used to highlight the various structures with their depths. Combination of information from field investigation and aeromagnetic data analyses revealed four main lithologies contrary to a single lithology that is indicated in the regional geological map. The derivative maps showed the characteristic magnetic signatures that are associated with the different lithologies in the area. Aeromagnetic data of the area has proved very useful in delineating geological contacts especially in inaccessible parts, such as the Ikeji Forest Reserve and places with limited outcrop exposures such as the swampy areas around Odunwo and Aba Sokoto. Keywords: Aeromagnetic, Second Vertical Derivative, Source Edge Detector, Total Horizontal

Geotectonothermal Evolution of Granitoids of Northwest Obudu Plateau, Bamenda Massif, Southeastern Nigeria: Geochemistry Evidence 1

Young Ezenwa Obioha , Barth Nwoye Ekwueme

2

Geosciences Department, School of Sciences Federal University of Technology Owerri, Nigeria Phone: +2348038774782; [email protected] Department of Geology University of Calabar, Calabar Nigeria, E-Mail: [email protected]; Phone: +2348033380719

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eochemical investigation of granitoids in Northwest Obudu, Southeastern Nigeria, was carried out in order to determine their petrogenetic significance to crustal evolution of African Continent. Results reveal that, granites, granodiorites, pegmatites and aplites constitute the main granitic rocks outcrops in the area. These are closely associated with migmatites gneisses, schists and granulites/charnockites which they intrude, Modal analysis shows that all the granitic rocks are enriched in quartz (16-31), plagioclase (An32-48 16-37), orthoclase (3-20), biotite (10-15), but relatively depleted in garnet (4-6 vol. %), hornblende, sphene and hematite. This is in accordance with their acid characteristics. Bulk rock geochemistry shows that all the granitic rocks are depleted in Fe2O3(total), CaO and MgO, with average values of 3.97wt.%, 2.58wt.%, and 1.03wt% respectively, but relatively enriched in SiO2 (70.7 wt.%), Al2O3 (13.81wt.%) and alkalis (6.37wt.%) average values, which is consistent with their intermediate-acid character. The CIPW Norm shows enrichment of Q(s) and Ab and depletion of Ol and Mt corroborating their granitic character. Chemical discrimination diagrams show that the granites were late-stage magmatic protoliths, emplaced dominantly in within plate to syn-collision tectonic setting. They played significant role in the tectonothermal evolution of the Pan African Continent. Keywords:

Geochemistry, Granitoids, Geotectonothermal evolution, Obudu Plateau, Protoliths, Pan-African Continent, Tectonic Setting. PAGE


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Structural Geology and Geochronology of Archaean Rocks in the Tonota Area, NE Botswana Moseki M.1, McCourt S.2 and Armstrong R. A.3 1

Geological Sciences, University of KwaZulu-Natal, Durban, South Africa [email protected] 2 Department of Geological Survey, Lobatse, Botswana 3 Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia

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he basement geology of NE Botswana comprises metamorphic and igneous rocks of Neoarchaean age subdivided into three main crustal terranes: the south-western part of the Zimbabwe Craton, the western part of the Central Zone to the Limpopo belt and a third terrane referred to as both the Shashe Belt (1) and the Motloutse Complex (2). The Tonota area forms part of this third terrane and lies adjacent to the Francistown Complex (2) a granitoid-greenstone complex that helps define the south-west margin of the Zimbabwe Craton (3). Recently published research shows that magmatism and deformation associated with the SW margin of the Francistown Complex can be linked to an Andean type continental arc along the edge of the (proto) Zimbabwe Craton between 2737Ma and 2647Ma [3,4,5]. The structural grain of this arc complex is defined by a NW striking, SW dipping foliation that is developed in both the supracrustal rocks of the Tati Schist Belt and associated granitoid gneisses in the Shashe area. The foliation in these gneisses carries a lineation defined by the preferred orientation of minerals and the elongation of deformed mineral aggregates. The lineation is upright on the foliation and plunges southwest parallel to the axis of minor folds compatible with high strain. This high strain zone has been interpreted as a thrust-sense ductile shear zone with NE vergence [2]. Similar kinematics have been recognised by Majuale (6) in the supracrustal rocks and associated granitoid gneisses that define the Matsitama Belt. The rocks in the Tonota area are similar in character to those around Shashe and Matsitama but the kinematics of the deformation structures in these rocks are very different. Foliation strikes NNE to NE and dips NW. Folds developed in the supracrustal rocks trend NE-ENE and deform bedding (S0) and a bedding-parallel foliation (S1) Map scale fold structures defined by the supracrustal rocks are Type-3 interference patterns compatible with NW-SE compression. The granitoid rocks of the Tonota area are variably deformed and regional foliation in them is co-planar with that in the supracrustal rocks. SHRIMP U-Pb zircon data from the granitoids indicate magmatism occurred between 2724Ma and 2631Ma and field relationships show deformation in the regionally extensive megacrystic gneiss occurred before 2631Ma.

High-Pressure Granulites and Eclogite at Adaklu Segment of the Pan African Dahomeyide suture zone in Southeastern Ghana, West Africa: Geotectonic Implications from New Field and Geochemical Data. Prosper M. Nude1*, Isaac Amponsah1, Daniel Kwayisi1, Yao Agossoumonde2, Samuel B. Dampare3 and Daniel K. Asiedu1 1

Department of Earth Science, College of Basic and Applied Sciences, University of Ghana, P. O. Box LG 58. Legon 2 Department of Earth Sciences, University of Lome, P. O. Box 1515, Lome, Togo. 3 School of Nuclear and Allied Sciences, P.O. Box LG 80, Legon, Accra Ghana. * Corresponding author Email: [email protected]

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ew field and geochemical data was obtained from outcrops at the Adaklu section of the Pan African Dahomeyide suture zone in SE Ghana, this area occurs between the well documented rocks at the Shai Hills in SE Ghana and Agou massif and the Lato Hills in Republic of Togo. The objectives were to use these data to decipher the evolution and geodynamic setting of these rocks. The main rock types identified in this work comprise granulites, namely (i) PAGE


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hornblende-garnet-pyroxene gneiss, (ii) pyroxene-garnet-hornblende gneiss, (iii) hornblendebearing gneiss (felsic gneiss), and eclogite and associated pyroxenite. The granulites and the eclogite were seen to have been affected by three deformational events. Evidence of prograde basalt/gabbroto-eclogite and retrograde transformations are preserved by exsolved rutile rods in garnet porhyroblasts and disequilibrium textures within the granulites and eclogites. From the major and trace elements variations the granulites and eclogite exhibit IAT, N-MORB, volcanic-arc tholeiite and calc-alkaline signatures. Typically the IAT and N-MORB features suggest the existence of a subduction zone complex where oceanic crust may have formed in either a back-arc basin or intraarc basin. High Ba/Nb (~36-262), Ba/Zr (~1.44-4.03), Ba/Th (~144-524) and U/Th (~0.5-1) relative to the primitive mantle and high Mg# and Ni contents in the pyroxenite suggest that the primary melt of this rock was derived from the lithospheric mantle wedge, not depleted by previous melt extractions and strongly modified by hydrous fluids. Taken together the formation of these rock suites can be attributed to continental subduction followed by collision and exhumation of oceanic lithosphere.

Jasperiods in the Buem Structural Unit of the Pan-African Dahomeyide Orogeny in Southeastern Ghana: New Field and Petrographic Evidence on Mode of Formation. 1

Daniel Kwayisi and Prosper M. Nude 1

1

Department of Earth Science, School of Physical and Mathematic Sciences, University of Ghana, P. O. Box LG 58, Legon. Corresponding author's Email: [email protected].

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he southeastern part of Ghana is underlain by the Neoproterozoic Pan-African Dahomeyide orogenic belt. This belt comprises three structural units namely; the Buem, Togo and Dahomeyan. The Buem Structural Unit is the most external part of the Dahomeyide orogenic belt, and consists of clastic units, limestones, jasperiods, volcanic rocks and associated maficultramafic units. Whereas the mode of formation of the clastic units, the volcanic rocks and the mafic units have been established, that of the Jasperiods remains debatable. This paper thus presents field and petrographic data on the jasperiods to infer their mode of formation. Our new field data shows that the jasperiods occur in small volumetric proportions with best exposures on the hills in BowiriOdumase, Kwamekrom, Akrokrowa, Kedjebi, Labolaboand Tintiano, trending generally in the northeast-southwest direction. They are mostly associated with the volcanic rocks, mafic-ultramafic units and the limestones. Occasionally, undifferentiated jasperiods-limestone-volcanic rocks association is observed in the field. Seldom, a gradual transition of volcanic rocks to jasperiods is also observed, particularly where limestones occur as inclusions in the volcanic rocks. At places pockets of limestones are observed within the jasperiods. The Jasperiods varies in colour from dominantly red, grey and subordinately green. They are generally fine grained, thickly bedded and composed dominantly of cryptocrystalline quartz with streaks of iron oxide and relicts of carbonates. The jasperiods have been affected by brittle-ductile deformation which is expressed as brecciation and weak foliation. Deformation in the jasperiods generally increases towards the east. The association of the jasperiods with limestone, volcanic rocks and mafic-ultramafic units and the occasional occurrence of undifferentiated jasperiods-limestone-volcanic rocks association may suggest the mode of formation of the jasperiods from metasomatic alteration of limestones. Hence the notion that the jasperiods are primary chemical sediments can be ruled out. Keywords:

Buem structural unit, jasperiods, limestones, metasomatism, volcanic rocks

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Review of Recent Developments in Petrogenetic and Geotectonic Studies of Rocks from the Pan-african Obudu Plateau, Bamenda Massif, Southeastern Nigeria 1

2

1

2

3

1

* Ukaegbu, V. U., Ekwueme, B. N., Beka, F. T., Ukwang, E. E., Nnabo, P. N. and Egesi, N. 1

Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria 2 Department of Geology, University of Calabar, Calabar, Nigeria 3 Department of Geology, Ebonyi State University, Abakaliki, Nigeria Mobile: +234(0)803-702-5850. E-mail:[email protected]

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ield mapping, petrographic and whole-rock geochemical studies of metamorphic and igneous rocks in parts of Obudu Plateau lying within the reactivated Pan-African unit of eastern Nigeria, were carried out with a view to determining the source, evolutionary history and tectonic setting of the rock units in the Plateau. The Plateau was subjected to medium to upper amphibolite-granulite facies grade metamorphism of the Barrovian type, resulting in the formation of complex suites of mainly metagreywacke-pelite sequences of migmatites, gneisses, schists and quartzites with some amphibolites, mylonites and cataclasites, and most of the metamorphic rocks were massively intruded by polymagmatic (calc alkaline granitic to olivine tholeiitic) rocks comprising charnockitic rocks and granites, and minor intrusions of pegmatites, aplites, dolerites, gabbro and peridotite. The metamorphic rocks were also subjected to pervasive Pan-African polyphase deformation with foliation, isoclinal folds and strike-slip faults, forming the major structural grains in mainly N-S to NE–SW (0o–30o) directions, which controlled the emplacement of the igneous suites. The setting of the plateau indicates rifting and collisional to non-orogenic emplacements in oceanic to ensialic environments. It is proposed that a proto oceanic sedimentary basin between two paleoplates of West African craton and a westward moving craton was closed during subduction and collision, and the rock units within the basin were deformed and largely homogenized, developing remarkable structural features consistent with crustal processes observed for the Pan-African units in the northcentral and southwest of Nigeria. The greywacke-pelite sequence and calc-alkaline to tholeiitic nature of the magmatism are suggestive of an Andean-type continental environment. Key words:

Obudu Plateau, Metasediments, Charnockitic and granitic rocks, Petrogenesis, Tectonics

The Petrology of Igneous and Metamorphic Rocks of North Western Region of Boki, Bamenda Massif, South Eastern Nigeria. 1

Ejikeme O. Ibegbulam, 2Ekere E. Ukwang

1

Department of Physics/Geology/Geophysics, Federal University, Ndufu Alike Ikwo, Ebonyi State, Nigeria. ([email protected]) 2 Department of Geology', University of Calabar, Calabar, Nigeria ([email protected])

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he crystalline rocks mapped within northwest Boki area (Latitudes 60 151N and 60 301N and Longitudes 80.451E and 90.001E) include migmatitic gneisses, augen gneiss, garnet-mica schist, garnetiferous granite, biotite gneiss, granodiorite, dolerite, basalt and gabbro. The dominant foliation trend in the area is N - S to NNE – SSW with dips in the northwest. This is an indication that the area was affected by the Pan-African thermotectonic events (550 ± 100ma). The 0. average dip value of the foliated rocks is 50 However few foliations trend in the NNW-SSE with dips in the northeast. The garnet–mica schist have good schistosity and partly preserved beddings (a syn-sedimentary deformational structure). The migmatitc gneiss have gneissose banding modified by shearing and injection of felsic materials consisting of the various cross-cutting quartzoPAGE


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feldspathic veins, and by contortions resulting from folding. There are fractures in the rocks several of which cut across the foliation trend. The minerals present in the metamorphic rocks which include feldspars + chlorite + garnet + biotite + quartz suggest a sedimentary progenitor. Field observations suggest that the gneisses form the basement for the emplacements of basic and granitic rock intrusions. The gneisses and the schist are extensively dissected by a network of crosscutting quartzofeldspathic vein/vein-lets of various orientations and average widths of about 7cm. The dolerites occur as dismembered lenticular enclaves within the metamorphic rocks. The paragenetic assemblages and structures present in the rocks suggest that the metamorphic rocks in the area have, at least, experienced high grade amphibolites facies metamorphism.

Agromineral Resources of Nigeria Olugbenga Okunlola and Siyan Malomo Department of Geology, University of Ibadan, Ibadan, Nigeria Federal University of Technology, Akure ,Nigeria

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n sub Saharan Africa and especially Nigeria, the pressure on agricultural land through repeated cultivation, harvesting, leaching, run off and erosion poses enormous restriction on soil nutrients for sustained crop production. 800,000 M tonnes of N, 100,000 tonnes of P and 1,700,000M tonnes of K every year are lost through nutrient depletion. Direct application of geological resources- Agro minerals, one of the cheaper, easily accessible means of soil nutrients enhancement has proved in this study to potentially enhance soil productivity in Nigeria. For example, occurring within the five inland sedimentary basins of Nigeria as indicated from the regional, qualitative and semi quantitative preliminary assessment carried out as part of this study are abundant and adequate resource of gypsum (125million tonnes), phosphate (58million tonnes), limestone (5.3 billion tonnes), marble ( 3.7 billiontonnes), peat/lignite (2.7 billion tonnes) and also K-feldspars within the late Pan African granitoids and pegmatides in the central and south central parts. Subjection of 70 samples of these various agrominerals from different parts of Nigeria to fertilizer/agronomic value test, such as Ca, K, Na, P, Cu, Mn, C, CEC, Acidity, available P, solubility and reactivity, on nutrients depleted and acid soils indicate varied potential as possible soil nutrients and supplements enhancer, thus improving the overall agricultural soil potential and hence increased food production for Nigeria.

Compositional and Industrial Appraisal of Clay Occurrence in Share Area, Northern Bida Basin, Northcentral Nigeria 1

1

2

Anthony A. Elueze, Abdulrauf B. Adebayo and Olawale K. Aromolaran 1

2

Department of Geology, University of Ibadan, Ibadan, Nigeria Department of Geological Sciences, Osun State University, P.M.B. 4494 Osogbo, Osun State, Nigeria ([email protected])

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ineralogical, chemical and physical characteristics of sedimentary clay bodies of Share area, North Central Nigeria have been carried, in order to determine the compositional attributes and evaluate the potential as industrial raw materials. The clay bodies are creamy white in colour, and occur as interbeds within the Bida Sandstone Formation, which is overlying the quartzite-dominated basement rocks of the area. PAGE


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Fifteen representative samples were collected at 0.8m intervals in three vertical pits, which are 4.0 m deep. These samples were prepared and subjected to mineralogical and chemical analyses and physical determinations. Mineralogical data from X-ray diffraction (XRD) analysis indicate high kaolinite (ca. 69.99%) content, with minor amount of clinochlore (ca. 1.15%). Other non-clay minerals are quartz and muscovite. Chemical data show that average SiO2, Al2O3, Fe2O3, TiO2 values are respectively 51.73, 32.56, 0.69 and 2.03%. CaO, MgO, MnO, K2O, Na2O and P2O5 contents are generally below 1.0 %. The physical and industrial determinations show that the clays are dense and moderately plastic. The fired pellets, which are generally white in colour, have shrinkage value of 2.2 to 4.3% and water absorption capacity of 14.04 to 17.74%. On the basis of mineralogical, chemical and physical characteristics and industrial determinations, the Share clays are considered useful as fillers in papers and paints. Similarly, they satisfy the necessary specifications as raw materials for chalks, extenders and carriers of fertilizers, pesticides and insecticides. Appropriate beneficiation, essentially to eliminate the quartz-bearing constituents, would be desirable for the applications in ceramics and refractories. Key words:

Clays, compositional characteristics, industrial appraisal, Share, Nigeria

Compositional Characteristics and Industrial Assessment of Isua-Akoko Clay Deposit, Southwestern Nigeria. Jacob Ogundipe1, A. T. Bolarinwa2 and Adebowale Adeseko3* 1

LCC Crush and Pave Quarry, Akamkpa, Cross River State, Nigeria 2 Department of Geology, University of Ibadan, Ibadan, Nigeria 3 Department of Remote Sensing and GIS, Federal University of Technology, Akure, Nigera * Corresponding Author. E-mail: [email protected]

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lay is a versatile mineral utilized in various manufacturing industries. In response to the challenges that may be posed by the demand for clay materials in Nigeria, indigenous clays with industrial potentials need to be investigated. Therefore, Clay samples in Isua-Akoko, area of Southwestern Nigeria was explored in order to determine its industrial potential. Twenty representative clay samples were collected from five pits dug in five locations in the study area and subjected to mineralogical, chemical and physical analyses. The Mineralogical results from the XRD analysis revealed kaolinite (10.40%)as the major clay mineral with minor amount of clinochlore (5.83%) (chlorite group) while quartz (66.65%) was revealed as the major non-clay mineral with albite (16.66%) and muscovite (4.08%) in subordinate amounts. Chemical composition data showed that the clay samples have average values of SiO2 63.74%, Al2O3 15.64%, and Fe2O3 5.03%, constituting more than 80% bulk chemical composition. The geotechnical tests results showed that all the clay samples were graded and classified as clayey sand. The bulk density between 1.91 and 2.6% and specific gravity 2.65 and 2.68%valuessuggests that the clay is dense with a moderate plasticity (LL Ca > Mg > Fe > Zn > Cu >Pb> As > Cd. Ca and K were above the WHO standard, high Ca could be associated to the calcium rich products found as waste in the area, while elevated level of K could be associated with the influx of weathering in the groundwater and the effect of human activities on the area. Inter-elemental analysis showed a strong correlation between Cd –Zn ('r'- 0.983), As – Ca ('r'-0.797) and Ca – Cd ('r'-0747), which indicates that the metals are governed by the same geochemical factors which are from the same anthropogenic source, K and Fe was observed to have weak and negative correlation in all the metals, indicating a different source. Index of geoPAGE


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accumulation (Igeo), revealed little to no contamination of the environment by trace metals. Potentiometric map of the groundwater showed contamination influx to be in southwest direction. The study can then be concluded to be contaminated with Ca and K due to the impact of man's activities in the environment. Public health effect of these metals could be Anemia, Kidney damage, Brain damage, Cancer and ultimately death. Keywords:

Contamination degree, Geochemical factors, Heavy metal, Public health, groundwater.

Groundwater Quality Attrition by Mechanic Workshop Activities in Abeokuta Metropolis, Ogun State, Nigeria Ojekunle Zaccheaus Olusheyi Federal University of Agriculture, Abeokuta. Ogun State E-Mail ([email protected], [email protected] )

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he influence of groundwater contamination is on the rise especially within the industrial vicinity as a result of carelessness as observed in many mechanic villages in Nigeria.

The objective of this study is to determine the presence and concentration of heavy metals within the demonstrated area so as to ascertain the long term effect of those activities on the resultant environment. The study was carried out at mechanic villages at Kotopo and Ajebo around Abeokuta, Ogun state. Ten Water samples was collected from these location and was analysed for the physical, chemical and heavy metals using standard procedures. Data obtained were analysis using descriptive and inferential statistics. The study revealed that all physical and chemical parameters are within the W.H.O standard except for nitrate (21.88 mg/L). Also, of all the eight heavy metals analysed, only cadmium (0.059 mg/L), cobalt (0.106 mg/L) and some points Manganese exceeds the W.H.O standard. Lead, copper, nickel and iron were below the detection limit in the water samples in many cases. The study concludes that the rate of heavy metal leaching to groundwater is relatively slow compared to the workload involving heavy metals usage and could be attributed to geologic formation of such soil and oily surfaces. The abundance of Nitrate could be from previous animal husbandry in such area. Nevertheless, precautions must be taken in order to prevent the excess leaching of heavy metal in the nearest future because of bioaccumulation especially chromium which was found in little concentration. Keywords:

Concentration, Groundwater, Heavy Metal, Lead, Soil, Mechanic Village

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Groundwater–Rock Interactions: An Excellent Tenacious Control on Water Quality in Some Parts of Ibadan Region, Southwestern Nigeria. *Ajibade, O. M., **Ogungbesan, G. O., and *Adesiyan A. A. *Department of Earth Sciences, Olabisi Onabanjo University, Ago-Iwoye, Nigeria. **Department of Earth Sciences, Ladoke Akintola University of Technology, Ogbomoso, Nigeria. All correspondence to the 1st author: e-mail [email protected]

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round water is of great uses for domestic, industrial and agricultural purposes. This study scrutinizes the quality of ground water in developing areas of Oluyole Provincial area of Ibadan metropolis which include Orita Challenge. Ninety (90) groundwater samples were collected and analysed for their ionic concentrations and other physico-chemical parameters in order to determine the quality and the level of water-rock interactions. Inductively Coupled PlasmaOptical Emission Spectometry (ICP- OES) was used and water quality was examined in respect to the recharge and discharge zones. The mean concentrated values for Fe and Al are greater than NIS2007 and EPA-2009 standards while total hardness (TH) and total organic carbon (TOC) values were high relative to the acceptable limits of drinking water guidelines (NIS) while the appreciable levels of Mg(2.4-15.7), Ca(9.6-34.7), CO3(132-336) TH(106-641.5) and Cl(16-80), levels had a great sway on the hardness and taste of the groundwater systems of the study area. A large part of the investigated area is neither polluted, nor contaminated. Water of the study area has a range of low to medium sodium hazard and excellent to good water class for groundwater. A water type of groundwater in the 2study area were recognized, Earth Alkaline water (predominantly HCO3, HCO3 – SO4, and SO4 ), the stiff diagram indicates that Ca and Na+K as the most dominant cations and CO3+NO3 as the most dominating anion in groundwater. Keywords:

Groundwater, rock, interactions, hardwater, total organic carbon

Hydrochemical Evaluation of Groundwater in 25 Neighborhoods in Douala Cameroon Suzanne Ngo Boum-Nkot, Beatrice Ketchemen-Tandia, Emvoutou Huguette, Rodrigue Ebonji, Seth Bertil, Yvon Nlend University of Douala, Cameroon. Email: [email protected]

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he watershed area of Tongo Bassa river is the largest watershed of Douala. It covers an area of 42,000 hectares divided in 25 districts with heterogeneous level of urbanization. This heterogeneity has a corollary with inequality sources of water supply. Nearly 50% of households use groundwater. The area has been sampled based on a mesh for a representative geographical coverage. 40 water points were sampled, two to three times for some of them, to follow seasonal evolution of hydrodynamic, physico-chemical and isotopic parameters. The used groundwater shows a high spatial variability of the mineralization from one well to another. The electrical conductivity values are between 20 to 1400 µs/cm indicating various sources of mineralization. Weak water mineralization could be du to a short residence time in the aquifer. In the study area, three chemical facies are represented. The shallow groundwater is characterized by sodium chloride-facies. The presence of this facies has more or less suggests widespread pollution of water. Nitrate (NO3) at levels beyond the WHO standard fixed at 50mg/l corroborates pollution due to human activity. The groundwater, from deeper drilling, has bicarbonate and calcique facies. PAGE


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The acquisition model and the differentiation of waters by mineralization degrees has been established using Stiff and Chaddah diagrams and the statistical study by Principal Component Analysis (PCA). The PCA has revealed that groundwater mineralization is defined by the Na+, K+ Cl-, Ca2+, NH4+ and Mg2+. The calcul of Base Exchange indices has revealed the importance of a basic exchange phenomena between clays and groundwater in the unsaturated zone. The minerals dilution line confirmed the basic exchange phenomena excluding any process related to minerals dissolution of the host rock. The interpretation of the isotope results from oxygen and deuterium diagram (ä18Ovsä2H) shows a similarity of the recharge process in the shallow aquifer for most of the sampled water points. This occurs primarily by direct infiltration and rapid precipitation. However, we note the presence more enriched heavy isotopes water reflecting evaporative recovery related to the thinness of the ZNS during the dry season. The isotopic contents are relatively close to the weighted average of the rains in the station of the Global Network of Isotopes in Precipitation, Douala-Hydrac. However, water from boreholes show a depleted content of stable isotope and indicates two periods of charging whose one could be attributed to the paleo recharging.

Hydro-Geological Investigations of Water Resources for Irrigation at North of Aderan, Kiama LGA, Kwara State. Nigeria 1

2

3

Ipoola. A. Okunlola ,Rasaq. Rahman Owolabi and Lateef. L. Kolawole 1

Department of Geological and chemical Sciences, Al-Hikmah University, Ilorin 2 Geosciences (Nig.) Ltd. Ilorin. Kwara State. 3 Department of Earth Sciences, Ladoke Akintola University of Technology, Ogbomosho. Correspondent: [email protected], 0803 - 630 – 3734

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study on surface and groundwater availability for irrigation farming on 50,000ha of land, northern part of Aderan were carried out using data acquired from satellite imageries, reconnaissance survey, geology, hydrology and hydrogeology investigations, then geophysical surveying. In the study area, four major rock units have been recognized namely gneisses, meta-sediments, amphibolites and granites. Migmatitic-gneiss is the dominant of these rock types. The satellite imagery interpretation aided in the classification of the study area into feasible and less feasible zones for the hydrogeological and geophysical surveys. The lineament map and the relief map showed that the drainage pattern is dendritic and structurally controlled, that the lineaments are mostly NNE-SSW oriented. Reservoir water level for three (3) consecutive years at Kainji and Jebba dams indicated that the lowest water levels are usually recorded during the wet seasons (June to August) while the highest levels are associated with dry seasons (September to April), So, make it available for seasonal irrigation requirements during the dry season (September to April) for a 60ha CP of 470,000m3 and pose no effect on the reservoir capacity of Jebba dam. Six (6) VES points spread across the study area showed promising hydrogeological tendencies after consideration of sub-surface fracturing, hydraulic link to subsurface water recharge area and potential yield on completion of drilling. Keywords:

Hydro geological investigation, Groundwater studies, irrigation suitability, assessing water resources, North of Aderan

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Impact of Geology and Groundwater on the Performance of Minna-Bida Road, North Central Nigeria Salome H. Waziri1, Nuhu M. Waziri1, Christopher Unuevho1 and Jacinta N. Chukwuma-Orji1 1

Department of Geology, Federal University of Technology, Minna, Nigeria Corresponding author: Salome H. Waziri (E-Mail: [email protected] Phone +2347035983684)

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he soils and rocks underlying Minna-Bida road in north central Nigeria were mapped with the view to determine their impact on the stability of the road they underlie. Thin section and XRD analyses were performed on four rock samples collected from outcrops along the road side. Regolith water table was mapped from hand-dug wells close to the road to determine the seasonal groundwater variation. Twenty eight water samples collected from hand-dug wells and boreholes within the neighbourhood of the road were subjected to chemical analysis to determine any possible relationship between lithology and ionic concentrations of groundwater. Permeability test was performed on soil samples obtained from trial-pits. Vertical electrical sounding was also performed along the road side. The field mapping, thin section and XRD results revealed that MinnaBida road is underlain by granites, migmatites, schists and sandstone. The chemical analysis revealed that the groundwater within the sandstone terrain of Minna-Bida road has the least ionic concentration. Results of the permeability tests revealed that permeability of the soils is generally low and not lithology related. Vertical electrical sounding revealed that the soil profile is composed of five geo-electric layers comprising laterite, sand, clay, weathered and fresh basement. The portion of the road that suffers consistent failure is underlain by migmatite gneiss and fractured granites that easily weather chemically in to impermeable clay. The clay absorbs water and swells in wet season, and shrinks in dry season. Persistent swelling and shrinking in alternate seasons create multiple cracks that eventually develop into pot-holes, which constitute the road failure.

Impact of Lithology on Groundwater Chemistry: A Case Study of Ikere-Ekiti Area, SW-Nigeria Abel .Ojo. Talabi Department of Geology, Ekiti State University, P. M. B. 5363, Ado-Ekiti, Nigeria. ( [email protected]).

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ydrogeochemistry and bacterial evaluations of shallow groundwater in Ikere-Ekiti was carried out to ascertain the effects of different rock units on the groundwater chemistry/irrigation. Twenty two groundwater samples were collected and analyzed using Atomic absorption spectrometer for cations and ion chromatographic method for anions determinations. Temperature (°C), pH and electrical conductivity (EC) (µS/cm) were measured in the field using pH Testr meter. Results of the analysis revealed that all EC values were less than 1000µS/cm indicating fresh water. The pH with average values of 9.48, 7.82 and 7.44 in migmatite, granite and charnockitic terrains respectively exceeded the approved standard (6.5 – 8.5) for drinking water only in two samples from migmatite and one sample from granitic terrain. Sodium was the dominant cation with average concentrations (mg/L) of 95.65, 38.33 and 6.61 in migmatite, granite and charnockite respectively while K+ ions in the same order of rock units have average concentrations (mg/L) of 60.49, 32.33 and 15.77. The average concentrations (mg/L) of Ca2+ ions in groundwater located on migmatite, granite and charnockitic terrains were 36.67, 24.63 and 10.98 2+ + respectively while those for Mg were 9.94, 7.48 and 4.57.The order of cation abundance was Na > K+> Ca2+> Mg2+. In respect of the major anions, Cl- was dominant with average concentrations (mg/L) incharnockite (187.20) within approved standard of 250mg/L while the average values (mg/L) inmigmatite (475.2) and granite (340.62) exceeded the standard value. Following the same sequence PAGE


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of rock units, HCO3 average concentrations (mg/L) were 34.6mg/L, 27.07mg/L and 25.7 which clearly showed that rock units have significant influence on the chemistry of groundwater in the area. Sulphate and nitrate were less dominant ions and the order of anions abundance in the groundwater was Cl-> HCO3-> SO42-> NO3-. Bacteria evaluation revealed that all sampled groundwater tested 8 9 positive to bacteria with TBC values (CFU/100ml) ranging from 1.76X10 to 1.78X10 in migmatite, 5 8 7 8 5.3x10 to 8.9x10 in granite and 2.55x10 to 8.2x10 in charnockite. Gibb's diagram revealed that chemical weathering of rock-forming minerals has contributed to solute source in the groundwater of the area. Water type on migmatite was mainly NaCl while granite and charnockite had NaCl and CaCl types revealing lithologic effects. Irrigation water quality assessment employing Sodium absorption ratio (SAR),Soluble sodium percent (SSP), Residual sodium bicarbonate (RSBC) and Permeability index (PI) revealed that the groundwater is suitable for irrigation purpose. Groundwater in the study area is low mineralized, chemically potable, suitable for irrigation but infected by bacteria pollutants. Differences in rock types affected the chemistry of the groundwater as reflected in their physico-chemical compositions, water facies and irrigation quality. Keywords:

Rock units, groundwater, bacteria, e-coli, irrigation

Impact of Manually Drilled boreholes on Water Supply in Maiduguri and Environs, Borno State, Nigeria 1*

2

1

Ibrahim Baba Goni, Mohammed Kachallah and Baba Musami Sheriff 1

2

PTDF Centre for Basinal Studies, University of Maiduguri. Borno State Rural Water Supply and Sanitation Programme, RUWASSA. * ([email protected])

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ater is essential for all aspects of life and meeting adequate supplies of good quality water becomes a major challenge for most developing countries including Nigeria. Maiduguri the capital of Borno State and environs are not spared from this challenge. In spite of the huge government investment in the water sector, public water supply to meet demands in this region is still a major problem. This has led to individuals drilling their own boreholes because of the failure of the public supplies. The numbers of these boreholes are increasing rapidly with the availability of low cost manual drilling. The activities of the manual drillers increased rapidly from the millennium (2000) to date, where there are over 600 members registered as an association operating individually or as an enterprise. To date there are over 5000 boreholes drilled by these manual drillers, which account for about 50% of water supply to Maiduguri and environs. There is the need to formalize the activities of these manual drillers for proper groundwater management. This will help in minimizing rampant cases of borehole failure and loss of vital subsurface geologic information from their activities. Government institutions and NGOs can interface with the manual drillers to build their capacity in order to improve their operations.

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Microbial Risk Assessment of Surface and Shallow Groundwater in Abeokuta and Its Environs, South-Western Nigeria 1

1

1

1

1

C. C. Mbachu , M. S. Aiyegbusi E. G. Okoye , O. Babalola , D. Adeniyi , J. A. Adesina1, M. N. Tijani2, O. A. Oyedeji1 and A. N. Nwegbu1 1

Nigerian Geological Survey Agency,Utako District, Abuja; P.M.B. 616 Garki ([email protected]) 2 Department of Geology, University of Ibadan, Ibadan

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n developing countries like Nigeria, emphasis is usually placed on surface and shallow groundwater for domestic needs. Surface and shallow groundwater occurrences in Abeokuta and its environs, covering an area of 625km2, were subjected to microbial analysis with the aim of assessing their microbial counts. Thirty-five surface and well-water samples were collected, eleven were from wells situated within densely-populated areas, thirteen from wells situated within sparsely-populated areas, while eleven were obtained from surface water. Total Heterotrophic Bacteria Counts and Coliform Counts were determined in the laboratory using Spread Plate method and Eosin Methylene Blue (EMB) Agar medium respectively following standard laboratory procedures. The microbial analysis of water samples from wells situated within densely-populated areas had counts that ranged from 6 – 2.9×104CFU/ml for Total Heterotrophic Bacteria Count (THBC); 0 – 2.64×102CFU/100ml for Total Coliform Count (TCC); and 0 – 7.4×103CFU/ml for Pathogenic Bacteria Count (PBC). The analysis also revealed that water samples from wells situated within 2 sparsely-populated areas had counts that ranged from 11 – 1.72×10 CFU/ml for THBC; 0 – 74CFU/100ml for TCC; and 0 – 3.8×103CFU/ml for PBC while river/stream samples had counts that ranged from 13 – 8.9×102CFU/ml for THBC; 3 – 54CFU/100ml for TCC; and 0 – 3.5×103CFU/ml for PBC. Analysis revealed twelve different bacterial loads and that wells within the densely-populated areas had the highest bacterial counts while surface water had the least which is probably due to dilution effect of direct precipitation. Bacterial counts in both surface and shallow groundwater samples were higher than WHO (2006) and NAFDAC (2006) maximum acceptable concentration of 0Cfu/100ml for all drinking water. This is indicative of anthropogenic contamination. It is therefore advised that both surface and groundwater resources within the study area should be treated before consumption. Keywords:

Total Heterotrophic Bacteria Count, Pathogenic Bacteria Count, Total Coliform Count, groundwater

Optimization of an Artificial Recharge- Pumping System for Water Supply in the Maghaway Valley, Cebu, Philippines (1)

(2)

(3)

Nafyad Serre Kawo , Yangxiao Zhou , Ronnell Magalso 1

Adama Science and Technology University, School of Applied Natural Science, P.O.BOX 1888, Adama, Ethiopia. (E-mail: [email protected]) 2 UNESCO-IHE, Institute for Water Education, Department of Hydrology and Water Resources, Westvest 7, P. O. BOX 3015,2601 DA, Delft, The Netherlands. 3 Metrocebu Water Districts Office, Cebu, Philippines

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his paper presents a coupled simulation-optimization approach to optimize an artificial recharge-pumping system for water supply in the Maghaway valley. The objective function is to maximize the total pumping rate through artificial recharge-pumping system while meeting constraints such as groundwater level draw down and bounds on pumping rates at each well. First groundwater flow models were constructed using MODFLOW-2000 code. The simulation PAGE


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models were then coupled with groundwater management optimization (GWM-2005) to optimize production rates. Under steady natural conditions, the significant inflow to the aquifer comes from river leakage whereas the natural discharge is mainly the subsurface outflow to the downstream area. Results from the steady artificial recharge-pumping simulation model show that the inflow from 3 artificial recharge basin is about 20,587 m /day and accounts for 77% of total inflow. Under transient artificial recharge-pumping conditions, the inflow contribution from the artificial recharge varies between 14,000 m3/day-20,000m3/day depending on seasons. The steady state optimisation results 3 show that the total optimal abstraction rate is 37,545m /day and the infiltration from artificial 3 recharge basin is increased to 29,313m /day for the current height weir. Transient optimization 3 results show that the average total optimal pumping rate is 36,969m /day for the current height of weir. The transient optimization for the increase of height of the weir by 1 meter and 2 meter show that the average total optimal pumping rate are increased to 38,768m3/day and 40,463m3/day, respectively. It is concluded that, the increase in the height of the weir can significantly increase artificial recharge rate and production rate in Maghaway valley.

Physicochemical Assessment and Bacteriological Studies of Hand-Dug Wells of Major Markets in South Western, Nigeria 1

1

1

Temitope. A, Laniyan, Olateju. O. Bayewu and Ganiyu. O. Mosuro

1

Department of Earth Sciences, Olabisi Onabanjo University, Ago- Iwoye, Ogun State, Nigeria; 2 Department of Geology, University of Ibadan, Ibadan, Nigeria Corresponding author: [email protected]

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apid population in developing nations has imposed stress on groundwater resources, thus the need to assess physicochemical and bacteriological impact of microbes on hand-dug wells along some major markets in Ibadan Southwestern Nigeria. Hand-dug well samples were measured sequentially, and total dissolved solute (TDS), pH, electrical conductivity (EC), salinity, and temperature were measured in situ. Water samples were analyzed at a Microbiology Laboratory. Most probable techniques used for micro-organism analysis were in three stages: presumptive test used for confirmation of Escherichia coli, confirmed test for total viable bacteria count (TVBC), and complete test to reconfirm the presence of coliform. Presumptive test showed high rate of E. coli in most of the hand-dug wells with (37.5 %). Confirmed test revealed Staphylococcus aureus to be 25 %, followed by Proteus vulgaris (14.6 %), Bacillus species (12.5 %), Pseudomonas aeruginosa (8.3 %), and Klebsiella spp. (2.1 %) respectively. Total viable bacteria counts are 500 to 192,000. TDS, pH, EC, salinity, temperature when compared with WHO (2006)and SON (2007)revealed parameters to be within the permissible limits except pH (5.8 to 9.56), and high values of the parameters were caused by organic matter. High E. coli in the study area revealed influence of human and animal fecal that could lead to urinary tract infection; Staphylococcus aureus that comes from sewage could lead to diarrhea, gastrointestinal disease, and multiplication in tissues. High value of pH and E. coli above the permissible limits showed contamination of hand-dug wells in the study area. Keywords:

Pathogens. Bacteriological. Coliform. Disease. Epidemic

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The Impacts of Subsurface Discharges of Wastewater Effluents on Groundwater Quality. 1

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1

1

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Ojekunle Z. O. , Adebayo A. A. , Idowu A. O. , Martin O. , Gbadebo A. M. and Adeyemi A. A.

1

1

Federal University of Agriculture, Abeokuta, Ogun State. Nigeria

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ater is required for continuity of life and sustainability of ecosystem. Hence, this study aimed at assessing the impact of subsurface discharges of wastewater effluents on water quality in Ikeja Industrial Estate, Lagos state with respect to drinking and domestic uses. Samplings were carried out for three months of which twenty (20) samples were collected in triplicates for laboratory analysis and points sampling georeferenced adequately. In-situ parameters (pH, EC, Temperature, hardness and TDS) were measured using a portable metre. Major cationstrace metals and anions were subsequently determined in the laboratory using standard procedure. Bacteriological analysis was carried out using Nutrient agar medium. Data obtained were subjected to descriptive (Mean and Standard Deviation) and inferential (ANOVA) statistics. The results obtained in ranged for pH, Temperature, EC, TDS, Alkanility and Hardness were: 7.43o o -1 8.35, 27 -28.3 C, 41-472 µScm , 21-239 mg/L, 1-25 mg/L and 14-55 mg/L respectively and those 2+ 2+ 32for cation and anions for Cl , Ca , Mg , PO4 , NO3 and SO4 in mg/L were: 19-95, 5-25, 3-35, 0.040.05, 0-43.32 and 1.86-4.82 respectively. Mean concentration for Heavy Metals (HMs) in mg/L were Cd>Pb. Some HMs concentration were above the international threshold for drinking water so also is the Coliform count above the acceptable limit hence, making the groundwater not suitable for direct consumption. Keywords:

Coliform, Groundwater, Nutrient agar, Water quality, Heavy metal

Water Quality Assessment of Ekulu and Asata Rivers in Enugu Area, Southeastern Nigeria, Using Physico-Chemical and Bacteriological Parameters D. N. Ken-Onukuba1, O. C. Okeke1, H. N. Echetama1, C. Enwelu2 and J. T. Ekere2 1

Department of Geology, Federal University of Technology, Owerri, Nigeria. Department of Civil Engineering, Federal Polytechnic, Idah, Kogi State, Nigeria. Corresponding author: [email protected]

2

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his study is aimed at assessing the impacts of human activities on the quality of Ekulu and Asata Rivers. Twelve (12) water samples (six (6) from Ekulu River and (six 6) from Asala River) were collected at different points along the regime of the two rivers and their physicochemical and bacteriological characteristics/parameters determined. Results of the study indicate that the two rivers do not satisfy the Drinking Water Quality Standard of World Health Organization (WHO) and Federal Ministry of Environment (FMENV) in terms of PH/acidity (values between 4.5 and 7.0 and outside the WHO Standard of 6-5-8-5); turbidity (values between 7.88 and 294NTU units and greater than WHO standard of 5.ONTU units); iron (values between 3.10 and 7.35 mg/l and greater than WHO standard of below 0.30mg/l; and coliform (values between 20 and 180 counts per 100ml and greater than WHO Standard of 3 counts per 100ml). Though Ekulu River is more acidic (lower PH values), more turbid (higher NTU units) and contains higher concentration of iron than Asata River. On the other hand, only Asata River do not satisfy the WHO Standards in terms of nitrate PAGE


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concentration (values between 8.9 and 25.9mg/l and greater than WHO Standard of 100mg/l): and chromium (heavy metal, values between 0.189 and 0.429 mg/l and greater than WHO Standard of 0.001mg/l) Human activities of mining at abandoned Onyeama Coal Mine, car watch and disposal of industrial/domestic wastes are believed to be responsible for poor water quality of the two rivers in Enugu area. On the basis of Piper Diagram Classification, Ekulu River may be classified as Calcium Chloride Type, while Asata River may be classified as Mixed Water Type. Local geology and human activities are responsible for different physico-chemical and bacteriological characteristics of the two rivers. Water from the two rivers, to be used for domestic and industrial purposes, shouled be adequately treated; and there is need to institute regular water quality monitoring programme for the two rivers. Water quality, chemical, bacteriological, local geology, human activities and heavy metals.

Keywords:

Water-Rock Interaction and Major Sources Controlling Groundwater Chemistry from a Basement Rock Terrain in Part of Ilorin West-Central Nigeria 1

2

3

Lateef L. Kolawole , Moshood N. Tijani , Rasaq, R. Owolabi , Ipoola A. Okunlola 1

4

Department of Earth Sciences, Ladoke Akintola University of Technology, Ogbomosho 2 Department of Geology, University of Ibadan. 3 Geosciences (Nig) Ltd. Ilorin. Kwara State. 4 Department of Geological and Chemical Sciences, Al-Hikmah University, Ilorin Correspondent: [email protected], 08032277598 and 08053506255,

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measure of the degree of influence of the major sources of variation in the hydrochemistry and water-rock interaction of basement aquifers for forty (40) samples were carried-out using combination of Component Analysis, Cluster analysis and Inverse geochemical modeling techniques. The cluster analysis defines two (2) major chemical water types, reflecting different hydrochemical processes. The order of abundance of major cations is Ca>Mg>Na>K. High Ca and Mg indicating weathering from primary mineral sources and that of major anions is HCO3>Cl>SO4. The Hierrachial Cluster analysis showed a total of two (2) clusters were, in which two spatial groundwater associations were identified based on Stiff diagrams generated from for the mean of the measured physio-chemical parameters used in the study. Group 1 is Na-Cl, group 2 is Ca-HCO3.The component analysis showed that PC1and PC2 represents the major geochemical processes taking place, due to the presence and dissolution of some carbonate silicate and evaporate minerals in the aquifer with PC3 indicating trace metal Contamination of Fe, Mn and Cr, due to low factor, reflecting the degree of confinement and less likely for aquifer to affect it by surface activities, such as waste disposal. High load correlation of Mg+ at PC1 indicates weathering of Mg+ containing silicate minerals like micas in the sediments. HCO3&Cl- compacted well under the first component (PC1), suggesting a similar source. The second principal components (PC2) has high positive loading for pH- HCO3, indicating carbonate mineral weathering on the hydrochemistry of groundwater. Inverse geochemical modeling along groundwater flow paths indicated that dominant processes are dissolution of dolomite, gypsumand halite, with consumption of CO2 and precipitation of calcite, Ca-montmorillonite, kaolinite and quartz. Keywords:

Principal component analysis, Cluster analysis. Inverse geochemical modeling, rock work interaction and major controlling factor of basement complex terrain of southwestern part of Nigeria. PAGE


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A GIS Mapping of Calcium and Magnesium Distribution in Parts of Central Plateau State, North-Central, Nigeria. Dibal H. U., Justina, M. D., Yenne, E. Y. and Fom, S. G. University of Jos, Department of Geology [email protected]

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dequate intakes of calcium and magnesium in water have been found to reduce the risk of cardiovascular diseases and diabetes especially, where adequate amount of these ions are not supplemented in foods. The dependence on waters abstracted directly from hand dug wells and other sources without any form of treatment and or regulation are of great concern to the health of humans and animals. Groundwater abstracted from hand dug wells and hand pumps without any form of treatment, are the main sources of water supply for rural inhabitants of central Plateau State, Nigeria. The aim of this study was to map out the distribution of calcium and magnesium using GIS in parts of central Plateau State. Multivariate analysis to explain the variation of these ions in aquifers of the area was also employed. Four rock types constitute the aquifers from which water is abstracted for drinking (migmatite, biotite granite, granite gneiss and basalts) exhibiting variations in their contents of calcium and magnesium. Content of calcium and magnesium are higher in the migmatite lithology as compared to the other rock types. Calcium and magnesium content also vary with depth of sampling, with concentration higher at depths of >5m in the migmatite lithology and higher concentration at depths of Mg>Na>K and HCO3> SO4>Cl >NO3. Most heavy metals were at levels below detectable limits, except (Fe), Zinc (Zn) and Copper (Cu) according to WHO (2004) standards. The soils are poorly graded sand with high inorganic clay having low to medium plasticity. The constant head permeability test indicated poor to very poor drainage characteristics. The first and second soil horizons reveal resistivity values of 18 to 45? m which are common to materials of poor drainage and permeability. The dumpsite is though unlined presented negligible contamination to the groundwater with the exception of Fe, Zn and Cu which were above the permissible standards. Geology, Hydrogeology, Engineering Geology. Dumpsite, Gbagede

Keywords:

Chemical and Mineralogical Characterization of Highly and Less Reactive Coal from Northern Natal Coalfield and Venda-Pafuri Coalfield, South Africa. Milton O. Kataka1 and Arnold R. Matiane1 1

Department of Mining and Environmental Geology, School of Environmental Sciences, University of Venda, P/Bag X5050, Thohoyandou, 0950, South Africa ([email protected]; arnoldmatiane@gmail. Com).

S

pontaneous combustion of coal has been a major hazard associated within the coal mining industry over centuries. It has been a major cause of underground fires in South African collieries and is also a common problem in opencast operations, spoil heaps and stockpiles. Spontaneous combustion incidents can happen anywhere in the coal mining industry, from mining, transport and storage to waste disposal. Previous studies indicate that there are various factors (e.g. intrinsic and extrinsic factors) that affect the spontaneous combustion of coals. This paper characterize highly reactive coal (spontaneous coal) from stockpile areas in Richards Bay from one of the mines in the Vryheid coalfields and less reactive coal (non-spontaneous coal) collected from run-of-mine product at Venda-Pafuri coalfield (Tshikondeni coal mine) to identify and delineate some important relationships between the highly and less reactive coal by tracing their similarities and differences among the spontaneous combustion parameters. This knowledge is necessary for better understanding of the highly reactive coal which combust spontaneously at stockpiles. Various tests were carried out to characterize these coals in terms of their intrinsic properties. These tests include ultimate, proximate, petrographic analysis and Glasser spontaneous tests. The ultimate and proximate analysis showed that spontaneous coal has high contents of carbon, oxygen, and volatile matter as compared to non-spontaneous coal, this makes spontaneous to be more susceptible to spontaneous combustion than non-spontaneous coal. These tests also showed that nonspontaneous coal has a high ash content as compared to spontaneous coal which confirms that less reactive coal is less susceptible to spontaneous combustion. Furthermore, through petrographic analysis it has been found that spontaneous coal has high total reactivity as compared to nonspontaneous coal. This further confirms that spontaneous coal is more susceptible to spontaneous combustion than non-spontaneous coal. The susceptibility of these coals was also investigated through Glasser spontaneous test where spontaneous coal was found to absorb more oxygen than nonspontaneous coal; this also indicates that spontaneous coal is more susceptible to spontaneous combustion since high oxygen absorption increase the susceptibility of coal to spontaneous combustion. Keywords:

Spontaneous, combustion, High reactive, reactivity, ultimate, proximate, Glesser PAGE


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An Assessment of the Environmental Impacts of Old Gold Mining in the Central Rand Gold Fields: Focusing on the Crown Mine Ratshalingwa Mulaudzi School of Environmental Sciences Department of Ecology and Resource Management, University of Venda, Thohoyandou P. O. Box 5050

T

he summary reports the research work undertaken to investigate/ assess the environmental impact associated with the old gold mining at Crown mine in the Central Rand. This work also includes attempts to come up with the mitigation strategies to solve the problems. The work looks at the environmental impacts associated with gold mining. The effects of tailing dumps on the environment have also been investigated thoroughly. The methods employed to acquire data and the way it was analysed have been explained. The field observation mainly involved survey factors like geology, soil, vegetation and slopes. The gullies, rills, slopes and physical factors on the tailing dumps were measured. Field collection of various samples and laboratory analysis of soil, leaves and water samples were undertaken. The data analysis methods employed are both qualitative and quantitative. The findings of the research show that the major environmental effects or problems were due to the old gold tailing dumps which were not well rehabilitated. This has led to water erosion and soil contamination due to pyrite and sulphides. The water eroded from the tailing dumps is eventually deposited into the stream and deteriorates the water quality. The major recommendation is to treat the tailings with chemical and physical techniques like stabilization and neutralisation of the pH. Then from there the use of biological methods likes planting of hypper accumulators to recover metals can also be used. After that rehabilitation of tailing dumps which involves plantation of vegetation on tailing dumps need to be undertaken. This will prevent and reduce the rate of tailing erosion and water contamination downstream. The gold mining company together with government should make sure that casual treatment of tailing dumps and environmental issue are minimised. This can be achieved by complying with different environmental legislations and policies.

Balneo-Economics: A New Research Frontier in Medical Geology 1

K. Nghargbu , R. Nghargbu

2

1

Department of Geology & Mining, Nasarawa State University, Keffi, Ngeria 2 Department of Economics, Usmanu Danfodiyo University, Sokoto, Nigeria Corresponding Author: [email protected], +2348036063841

M

edical geology research has progressed more rapidly in the 21st century with deepened scientific approach to the understanding and application of balneological materials and procedures in the health care and pharmaceutical industries. Based on the increased emergence of balnear centers across the globe, as well as the increased training of medical geologists and balneotherapists, not to mention the increasing burden of geomedical diseases on the society, as well as the discovery of more geomedical resources, the need for contemporary researchers in this field to develop streamlined topics in medical geology for the purpose of training is important. Books, modules, handouts, lecture notes, audio-visuals, questionnaires/interviews will form part of the materials for training of the health practitioners/medical geologists. Methods will include; semester/contact hours teaching, workshops, seminars, symposiums and short courses. Suggested areas of Balneo-economics course content will include; balnearhealth systems management, cost effectiveness and efficiency of health resort medicine, and measurement of satisfaction levels of patients who have undergone balneotherapy. Other topics will include; PAGE


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profitability of balneological related industries, demand/supply and market size of balneological products, quantification of the contribution of balneological industries to Gross Domestic Product(GDP), health impacts, as well as the mineral/mining economics of geomedical resources and other related fields. These all will be put together in a proposed new area of research titled Balneo-Economics. The proposed subject for training in health resort medicine is important because it provides deeper requisite knowledge of the direct economic impact of SPA medicine and Balneological resources on humans and the national economies. Teaching such a subject to economic, earth science, medical and health professionals will not only broaden the knowledge horizon of such practitioners, but also widen their job scope upon graduation and sharpen their skills in the management of health resorts. Keywords:

Balneo-Economics, cost effectiveness, training, economic tools, health resort medicine

Heavy Metals in Arable Soils and Food Crops and Health Risk Implications Around Old Pb-Zn Mining Areas in Enyigba, Southeastern Nigeria. 1

Smart C. Obiora, 2Anthony Chukwu and 3Theophilus C. Davies 1

Department of Geology, University of Nigeria Nsukka Department of Geology, Ebonyi State University, Abakaliki, Nigeria. ([email protected]; [email protected]) 3 Faculty of Natural Sciences, Mangosuthu University Technology, Umlazi/Durban, South Africa ([email protected]) 2

T

his study determined the heavy metals concentration in arable soils and associated food crops around the Pb-Zn mines in Enyigba, Nigeria, and metal transfer factors were calculated. Airdried samples of the soils and food crops were analyzed for 8 known nutritional and toxic heavy metals by Inductively Coupled Plasma - Mass Spectrometer (ICP-MS) method. Eighty seven percent of all the 20 sampled soils contain Pb in excess of the maximum allowable concentration (MAC) set by Canadian Environmental Quality Guideline (CCME) and European Union (EU) Standard, while Zn in thirty-one percent of the samples exceeded the CCME for MAC of 200 mg/kg. All the food crops, with the exception of yam tuber, contain Pb which exceeded the 0.43 mg/Kg and 0.3 mg/Kg MAC standards of EU and WHO/FAO respectively, with the leafy vegetables accumulating more Pb than the tubers. The metal transfer factors in the tubers and the leafy vegetables were in the order: Mo > Cu > Zn > Mn > As > Cd > Cr > Ni > Pb and Cd > Cu > Zn > Mn > Mo > As > Ni > Pb > Cr, respectively. Risk assessment studies revealed no health risk in surrounding populations for most of the heavy metals. However, Pb had a high health risk index (HRI) of 1.1 and 1.3, in adults and children, respectively for cassava tuber; Pb had HRI > 1 in elephant grass while Mn also had HRI > 1 in all the leafy vegetables for both adult and children. This high level of HRI for Pb and Mn is an indication that consumers of the food crops contaminated by these metals are at risk of health problems such as Alzheimers' disease and Manganism, associated with excessive intake of these metals. Further systematic monitoring of heavy metal fluxes in cultivable soils around the area of these mines is recommended. Keywords:

Soils; food crops; heavy metals; health risk; Pb-Zn mines; Enyigba.

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Linking Geochemistry to Human Health in Contaminated Mining Areas in Kadoma District, Zimbabwe Mudimbu, D.1, Meck, M. L.1 1

Department of Geology, University of Zimbabwe, MP167, Mt Pleasant, Harare, [email protected]

G

eochemical elements released through natural as well as mining operations into agroecosystems pose a serious threat to the health of communities that reside in mining towns even well after the cessation of mining activities. In Zimbabwe the issues of residential and agricultural land contamination through mining activities; the extent of contamination; toxic element migration pathways and routes of human exposure are poorly understood. Geochemical maps, produced during this study, revealed areas of significantly high concentrations of potentially harmful elements (PHEs) above background values. Soils and stream sediments close to and downstream of abandoned and active mining areas had arsenic, chromium, lead and mercury levels well above the maximum permissible levels based on human health risk. Through spatial analysis, densely populated areas within the Kadoma District were found to fall within the zones of enrichment of PHEs. Historical medical data revealed high percentage populations of cases of chronic renal failure, chronic heart failure, mental illnesses and still births within the Kadoma district. Initial results are indicative of zones of PHE enrichment being spatially linked to the elevated cases of chronic renal failure, chronic heart failure, mental illnesses and still births in the Kadoma District. Keywords:

Potentially harmful elements, PHEs, toxicity, spatial analysis, environmental geochemistry, medical geology, Kadoma, Zimbabwe

Medical Geology Applications of an Africa Geochemical Database Theophilus Clavell Davies Department of Geology, University of Nigeria at Nsukka; (Email: [email protected])

T

he significance of a complete, high quality Africa Geochemical Database(AGD) for addressing the range of Earth and environmental science issues (e.g., mineral exploration, resource evaluation, agriculture, land use planning, processes of crustal evolution, modelling of environmental systems) cannot be over-emphasised; because, for such applications to be made in a robust fashion, we need to understand how the Region's unique and complex geochemical landscape was carved out in the first place. The distinctive nature of Earth processes such as intense tropical weathering, leaching, erosion, podzolization and gleying, as well as later imprints of urbanisation and industrialisation, have engendered the mobilisation and clear redistribution of all but the most refractory elements. As a consequence, it is not uncommon to find large tracts of the Continent's surface environment containing anomalous trace element contents or deficiencies in essential micro-nutrient elements. Through water and food crops, extremes in trace element variation in soils are transmitted into the food chain, with often undesirable consequences for human and animal health. It is thus considered that one of the most important applications of an AGD would be in understanding the hydrological, chemical and biological processes that determine the behaviour of nutritional and toxic elements in the surface environment, in relation to how they may affect the health of man and animals (Medical Geology). This is so, because most of the population still live close to the land, and depend on it for their daily sustenance. Important scientific problems that would confront the construction of an AGD include defining and understanding“regional background”, and the evolution of appropriate sampling and analytical protocols that would take into account the Regions' unique and complex element distribution PAGE


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patterns. These problems are apparently intractable, but are not unsolvable. Longstanding operational and logistical problems that have impeded previous (largely uncoordinated) efforts at an AGD compilation include the limited availability of state-of-the art analytical instrumentation. An even more important limitation is the dearth of a sufficient number of highly skilled analytical geochemists and other technical personnel located at appropriate regional centres, who are able to install, operate, trouble-shoot and maintain modern analytical equipment. These problems are compounded by the lack, up to now, of adequate international funding to undertake such a high precision and systematic mapping exercise. In this presentation, recommendations are presented for carrying out a successful and complete compilation of a high quality AGD that would be invaluable for studies in Medical Geology, as well as in an array of other multipurpose, multi-national environmental applications; and proposed measures given for counteracting potential limitations in its development. Keywords:

Africa, geochemical database, applications, Medical Geology, addressing issues

Mineralogic Constituents of Airborne Dust and Its Potential Health Implication in Ibadan, Southwestern Nigeria. Tesleem Kolawole1, Akinade ShadrachOlatunji2, Andreas Taubert3, Christina Günter4 1 Department of Geological Sciences, Osun State University, Osogbo Nigeria 2 Department of Geology, University of Ibadan, Ibadan Nigeria 3 Institute of Chemistry, University of Potsdam, Potsdam Germany 4 Institute of Earth and Environmental Science, University of Potsdam Germany Corresponding Author's E-mail: [email protected], +2348053053600

A

irborne dusts are of great concern because they affect the climate, human health and ecosystems. In this study airborne dust were collected using high volume air sampler and were analysed with scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) for their mineralogical composition. Rock and soil samples were analyzed using X-ray diffraction (XRD). It was observed that the majority of the airborne particles were aluminosilicate minerals such as clay minerals, quartz, feldspar, mica and amphibole. There is consistency in the mineralogical result obtained from petrological studies and XRD analysis of rocks with dominant minerals being quartz, feldspar, mica and amphibole. In addition to these minerals, clay minerals especially kaolinite were found in soils and are believed to be a result of chemical weathering of the rocks. Airborne dust constituted more than 66% of the total particle analyzed and 80% are in coarse mode with average size of 5.2µm. They are mostly irregular in shape and sourced basically from local geology. Apart from the aluminosilicate and silicate minerals that are believed to be sourced from the lithology of the study area, particles rich in Fe, Ca and Ti were observed mostly in fine fraction of the airborne particles and they are believed to have anthropogenic origin. Interactions of exogenic particles with mineral dust were observed in the association of sulfate with clay minerals. The composition of dusts is derived from crustal and anthropogenic sources. The significant presence of silicain the particles could pose serious health hazard to the human population. Keywords:

Airborne Dust, Scanning Electron Microscopy Energy Dispersive Spectrometry (SEM/EDS), Exogenic Particles, High Volume Air Sampler, Single Particle Analysis.

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Occurrence and Distribution of Fluoride in Drinking Water Sources of Kaltungo Area, Northeastern Nigeria Dibal, H. U. and Okpanachi, I. S. Department of Geology, University of Jos [email protected]

C

onsumption of fluoride in drinking water sources in Kaltungo area, Northeastern Nigeria manifests in form of dental fluorosis especially among children. The aim of the study was to assess the occurrence and distribution of fluoride in different water sources used for drinking purpose.A total of 40 water samples from different water sources, 6 rocks and 4 soil samples were collected. Water samples were analysed for cations and anions, minor and trace elements. Cation = analyses were carried out using combine ICPAES/ICPMS method. The anions (Cl , SO4 , NO3 and F ) were analysed using UV Multi-Ion Parameter and bicarbonate was by titration method. Fluorine in rocks and soils were analyzed using the fusion method. Results indicatea range of 62 – 1100ppm in rocks and 164 – 560ppm in soils. The lowest content of fluorine (62 ppm) in rocks was obtained in the Bima Sandstone and the highest (1100 ppm) was obtained in the coarse porphyritic hornblende biotite granite which constitutes the major aquifer lithology from which water is abstracted for use in the community. Fluoride in water correlates with calcium ion at 0.059 significant levels but it shows significant positive correlation with sodium and pH with correlation at 0.679 and 0.692 respectively. Generally, results from water analyses show all parameters to be within the WHO recommended limit for drinking water purpose except for fluoride which has 65% of its values above WHO recommended upper limit of 1.5mg/l. High concentration of fluoride ion in water indicates the source to be from the host rock coarse porphyritic hornblende-biotite granite. The mineral constituents of the host rock (hornblende and biotite) may be hosting fluorine minerals which are leached and mobilized to the groundwater under alkaline condition .

Seasonal Variation in Fluoride Content in Groundwater of Langtang Area Dibal, H.U., Winifred, D., Lekmang, I.C and Nimze, L. W University of Jos, Department of Geology [email protected]

T

hirty seven and thirty groundwater samples were collected at both the dry and the peak of the rainy season andanalysed for fluoride and other cations and anions in drinking water sources of Langtang area. The aim of the study was to determine variation in fluoride content with respect to the seasons. Fluoride in water was determined by the Ion Selective Electrode (ISE) and the cations by the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The anion (sulphate) was determined by Multi – Ion Colorimeter, bicarbonate and chloride by titration method. In addition fluorine content in aquifer materials from a borehole section were determined by Fusion method. The two seasons show variation in content of fluoride in groundwater. Fluoride content in groundwater is higher in the dry season ranging from 0.13 – 10.3 mg/ l compared to the 0.06 – 4.60 mg/l values in the rainy season. Content of fluorine in the aquifer materials is lower from 0 to 7.95 m (0.01 wt %). However, fluorine content increases with depth, from 7.95-10.60 m with concentration of (0.04 wt %), 10.60-13.25m (0.05 wt %) and 13.25-15.70 m (0.07 wt %). The content of fluorine however, decreased at depth 15.70-18.55m with concentration of (0.02 wt %) even with fluorite mineral in the aquifer material at this depth. Dilution of fluoride ion as a result of rain input which recharges the aquifer may be the main reason for lower values recorded in the rainy season. Over fifty and sixty percent of waters in both dry and rainy season have fluoride concentration above the WHO upper limit of 1.5 mg/l. Consumption of these elevated values of fluoride in groundwater of the study area, clearly manifest as symptoms of dental fluorosis. PAGE


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Assessing Contaminant Loads within a Gold Tailings Dam using Geostatistical Techniques, Case Study from South Africa Oluseyi Abegunde1,Changhong Wu, A. M. Siad and Charles Okujeni University of the Western Cape. Science Faculty. Earth Science Department. Private Bag X17. Cape Town. South Africa

A

multivariate statistical analysis was performed on geochemical data from a gold tailing dam samples in Randfontein, South Africa. The objectives of the study were to predict the potential load of heavy metal containments and acid mine drainage generation and mobilization. Geochemical mass balance, factor analysis and cluster analysis were performed on the analysed samples. SiO2 (84.24%), Al2O3 (625%), Fe2O3 (2.64%) and LOI (3.28%) accounted for about 97.05% of the whole concentration. Total Sulphur ranges from 0.26-2.71%.The relative abundance of trace elements are Zr (122.80ppm)>As (105.28ppm)>Zn (73.02ppm)>Ni (69.31ppm)>Ba (58.59ppm)>Pb (42.91ppm)>Cu (35.43ppm)>U (25.53ppm). The tailing dam was characterized into four distinct zones. Two main clusters were observed in which each cluster could be grouped into two sub-clusters each. Four factors were extracted based on the analysis. This factor explains about 100% variance within the data: (Factor 1 = 37.25%; Factor 2 = 25.49%; Factor 3 = 15.69%; Factor 4 = 21.57%). The geochemical mass balance identified the loss and gain alteration observed within the four layers. These results created a possible model on which remediation processes can be based upon. Keywords:

Acid Mine Drainage, geochemical mass balance, factor analysis, cluster analysis, geochemical data, Randfontein 37.2525.4915.6921.57

Assessment of Soil and Stream Sediment Quality in Shikira Mining Sites, Niger State, North-Central Nigeria using Environmental Pollution Indices 1

Amadi A. N., 1Ebieme E. E., 1Musa A., 1Olasehinde P. I., 2Dan-Hassan M. A., 1 3 Ameh M. I. and Shaibu I. 1

Department of Geology, Federal University of Technology, Minna, Nigeria Rural Water Supply and Sanitation Department, FCT Water Board, Garki, Abuja 3 Department of Geology, Federal University Gusau, Zamfara State, Nigeria * Corresponding Author's Email Address: [email protected] or [email protected]; Phone No.: +234-80377-29977 2

E

nvironmental pollution indices are effective tools used to communicate information on the quality of soils and sediments to policy makers and the general public. They provide efficient means of assessing geogenic and anthropogenic sources of contamination in an area. The quality of soil and stream sediment in the vicinity of Shikira mining sites were investigated with emphasis on contamination by heavy metals. A total of 35 soil samples and 15 stream sediments were collected and send to Central Laboratory, Federal University of Technology, Minna and National Geosciences Research Laboratory, Kaduna for analysis. The mean concentrations of Mn, Cd, Hg, Pb, Cu, Zn, Co, Fe, Ni and Ag in ppm are as 249.06, 87.57, 50.17, 194.41, 32.94, 38.54, 0.99, 27511.52, 8.952 and 0.35 respectively. The mean value of Cd, Pb, Hg, Fe, Mn, Cu and Ag are higher than their respective average crustal abundances which signify their enrichment in the soil and PAGE


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sediment. The laboratory results was elucidated using pollution indices such as geo-accumulation index (Igeo), contamination factor (CF), degree of contamination (DC), enrichment factor (EF), pollution load index (PLI) and metal pollution index (MPI). The results of the computed indices also confirm that the soils and sediments in the area are extremely contaminated by Cd, Hg, Fe and Pb, moderately contaminated by Ag, Mn and Cu and uncontaminated by Zn, Co and Ni. The consistency in the results of the computed pollution indices is an indication that artisanal mining have negatively affected the soil and sediment quality in the area and by extension the water quality due to soilgroundwater and sediment-surface water interaction. The deterioration of the soil and sediment may be attributed to the gold mining in the area and is enhanced by the weathering and dissolution discarded rock. Bioremediation and phytoremediation of the Soil and sediment is recommended for the area.

Geochemical and Health Risk Assessment of Sediments within and Around Artisanal Gold Mine Sites in Southwestern Nigeria. 1

Odukoya A. M., Olobaniyi, S. B. and Ogunsola, E. O. 1

2

Department of Physics, Covenant University, Ota Department of Geosciences, University of Lagos, Nigeria. [email protected]

T

his paper critically reviewed the state of Artisanal gold mining in Nigeria, its adverse effects on environment and associated health hazards.

Geochemical assessment of stream sediments within the vicinity of both abandoned and active artisanal mine sites in Southwestern Nigeria were carried out using Inductively Coupled Plasma Mass Spectrophotometer (ICPMS) at ACME laboratories, Canada to determine 56 major and trace elements. The enrichment factors calculated show that sediments in the study area fall within background to moderate enrichment with Cu, Ag, Ni and V, background to strong enrichment with Pb, Zn, Co, Mn, Fe, Cr, Ti and Nb, background to very high enrichment and background to minimal enrichment with Th and Cd respectively. The ecological risk index show that sediments fall within low risk index with Zn, Ni and Cr, moderate risk index with Cu, considerable risk index with Pb and very high risk index with Cd. Potential ecological risk factor (RI) ranged between low to considerable risk of toxic metals to the environment. The total chronic hazard quotient index of oral exposure to sediments contamination in the study area (THI) ranged between 1.58 and 22.69 for children and 0.28 and 4.05 for adult which indicate moderate to high hazard exposure. Keywords:

Artisanal mine, Sediments, Health risk, Ilesha, Toxic Elements

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Geochemical Assessment of Sediments in Osun and Erinle Rivers, Southwestern Nigeria Okunola O. W.,*and Olatunji A. S.** * Nigerian Geological Survey Agency, Utako District, PMB 616, Abuja ** Department of Geology, University of Ibadan, Ibadan. Corresponding author: Okunola O. W. e-mail: [email protected]

O

sun and Erinle rivers drain a very large area comprising both natural setting activities and Osogbo, a major city in Southwestern Nigeria. This study was undertaken to determine the spatial distribution of elements in the rivers sediments, ascertain their sources and the dominant geochemical phase in which the elevated elements occur in sediments. Thirty-four sediment samples were purposively collected from Osun (urban) and sixteen from Erinle (suburban) and their tributaries. Ten samples of the predominant rock types (schist and gneiss) were also collected. The samples were digested and elemental analysis carried out with ICP-OES. The bioavailable phases of elements with elevated concentrations were determined by sequential analysis. The ArcGIS was used to generate geochemical maps. The trace elements data were analysed using geo-accumulation index (Igeo), Enrichment Factors (EF) and Contamination Degrees (Cdeg). Correlation and R-mode factor analyses were used to ascertain the geochemical source of the elements. Copper, Pb, Zn, Cd and Mn showed elevated concentrations in sediments when compared with the results from rocks. High percentage of Pb (26.7%-89.5%), Cu (35.7%-60.2%), Zn (49.2%–65.5%), Cd (49.3%-73.4%) and Mn (40.6%-58.6%) are hosted by the bio-available phases. The geochemical maps revealed elevated concentrations of Cd, Pb, Cu and Zn in urban area, indicating anthropogenic input. This was further confirmed by the calculated Igeo, EF and Cdeg. Significant correlations (p 0.05). Cobalt, iron, nickel and chromiumwere the dominant trace elements in the AMD. There is need for the relevant government agencies to sensitize the local community on the potential health risks that are associated with the use of AMD for domestic and irrigation purposes. Keywords:

Acid mine drainage, trace elements, mine wastes, coal mine, sulphide,

Preliminary Investigation of Trace Elements Concentration in Dust from Tin Processing Mills in Jos - Bukuru Area, Northcentral Nigeria Daspan R. I., Bello, A. O., Dibal H. U and Lekmang I. C University of Jos, Department of Geology

T

he Jos – Bukuru Biotite Granite is the largest of the biotite granite belonging to the Younger Granite province of Nigeria. The rock hosts the tin and columbite mineral which on weathering released them forming the alluvial deposits mostly along stream channels. These th minerals were extensively mined in the early 19 century and remained active until late 1970s. Mining and processing of these minerals is still ongoing but on smaller scales around the Jos – Bukuru area. The aim of this work was to determine the concentration of trace element in dust generated during milling and processing of Tin and associated minerals. Fifteen dust samples were collected during the air floating and after floatation operations in nine different processing sites by placing filter papers at designated locations. Dust samples were analysed by Inductively Coupled Plasma Optical Emission Spectrometry. Generally, in all the processing mills Pb, Zn, Th, U is quite high. Pb ranges from 204.5 – 1177, Zn, 67.0 – 1,272, Th > 200 in all samples, U, 186.5 – 1623, As, 0.3 – 233.7 ppm respectively. Anthropogenic factor and index of geo-accumulation calculated for some of the trace elements indicate that the contamination level of trace elements ranges from uncontaminated (Ni), Uncontaminated to moderately contaminated (V, Co, Fe, Cr, Ti), contaminated to highly contaminated (Cu Se, Pb, U, Th, Zn, As and Mo). The use of mask to cover the nose and other protective clothing for other parts of the body during floating operations is not practiced, hence inhalation of this dust by workers posses a great risk to health. Keywords:

Younger Granites, Columbite, Tin, Dust, Anthropogenic, Geo-accumulation, contaminated PAGE


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Characterization of Ashes of Outcropping Coals, Produced in Artisanal Ovens in Moatize Area, Mozambique. Possible Applications 1

1

Lopo Vasconcelos and Moisés Matlhombe 1

Departamento de Geologia, Universidade Eduardo Mondlane, CP257 Maputo, Mozambique ([email protected]).

I

n Moatize Coal Basin, several coal seams outcrop, and local population typically extract it for use as domestic fuel and as fuel for artisanal ovens in the brick production. In the latter case, resulting ashes from burning coal are discarded into the surrounding areas, resulting in negative impact to health and the environment. To minimize these problems, the idea of studying these ashes was raised so as to decide on their possible use in small local industries so that it could contribute to improving the economic situation of the populations involved. To this end, 7 ash samples were collected from differentovensand from coal used in the ovens. The chemical composition of the ashes produced in the ovens (CzF) and produced from burning the coal in the laboratory (CzL) were analyzedfor the percentage of oxides and the concentration of some trace elements. Ash classification according to ASTM C618-15 was applied to the results obtained for CzF. Control on the time of combustion and temperature of burning in the artisanal ovens was not possible. As result, ashes produced have different aspects, which can also be due to different mineral content of coals used or to contamination by brick material during dismantling of ovensat the end of the burning of coal and the cooking of bricks. Both CzF and the corresponding CzL don't show significant differences on their chemical composition. Both are silico-aluminous, with SiO2 varying between 53.8-67.9% for CzF and 42.263.7% for CzL, and Al2O3 varying between 18.1-25.9% and 19.1-24.8% for CzF and CzL respectively. The remaining oxides occur in the following percentages (first figures for CzF and then CzL) Fe2O3:0.9-6.4% and 0.9-21.8%; MgO:0.5-2.6% and 0.4-6.1%; CaO:0.2-5.9% and 0.9-12.6; Na2O:0.1-2.2% and 0.1-2.0; K2O:1.8-3.8% and 1.6-3.7; TiO2:0.9-1.4%and 1.1-2.9%; P2O5:0.1-0.9% and 0.5-1.6; MnO:?0.01-0.06% and ?0.01-0.07; Cr2O3:0.007-0.01% and 0.01-0.12. Trace elements analyzed are: Ba, Ce, Co, Cu, Nb, Ni, Sc, Sr, Y, Zn, Zr. There is a substantial difference on the concentrations of these elements between CzF and CzL. In the latter, the concentrations are often greater than the Clarke Value for coal ashes, which doesn't happen in CzF, whose concentrations are way below the respective Clarke Value. Therefore negative environmental and health implications by the latter are improbable. The reason for these differences in the two types of ashes was not studied yet, as the main concern of the study was the CzF. But it may be due to different temperatures of combustion that may be higher in ovens and therefore trace elements disappear by volatilization. According to the ASTM standard mentioned above, ashes are classified as Class F, where SiO2+Al2O3+Fe2O3>70% (CzF 86.9% avg.), CaO

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