Arab J Geosci (2015) 8:1977–1991 DOI 10.1007/s12517-014-1313-2
ORIGINAL PAPER
Petrographic and geochemical studies of Proterozoic sandstones of Patherwa Formation, Son Valley, India: implication for provenance and weathering history Abul Hasnat Masood Ahmad & Ruchi Agrawal & Roohi Irshad
Received: 13 April 2013 / Accepted: 7 February 2014 / Published online: 12 March 2014 # Saudi Society for Geosciences 2014
Abstract The petrography as well as major, trace, and rare earth element (REE) compositions of Mesoproterozoic Patherwa Formation sandstones have been investigated to determine provenance, and weathering history of the sediments. The sandstone is fine to coarse grained, moderately to well sorted, and subangular to rounded. The sandstones are mineralogically mature and mainly quartzarenitic to subarkosic in composition. The A-CN-K ternary plot and CIA values suggest that the source rocks suffered from moderate chemical weathering. Various geochemical discriminants, elemental ratios like La/Sc, Th/Sc, Th/Cr, (Gd/Yb)n and negative Eu anomalies indicate granite source for these sandstone with a minor contribution of granodioritic and volcanic input in a passive margin setting. Keywords Petrographic and geochemical studies . Patherwa Formation . Sandstone . Son Valley . India
Introduction The mineralogical and chemical compositions of terrigenous sedimentary rocks are indicative of several process variables such as provenance, weathering conditions, transportation, diagenesis, climate, and tectonism (Taylor and McLennan 1985; Bhatia and Crook 1986; Cox et al. 1995; Nesbitt et al. 1996; Cullers 2000; Rieser et al. 2005; Al-Harbi and Khan 2008; Ghosh et al. 2012). In geochemical studies of the clastic sedimentary rocks, the major, trace and rare earth elements (REE) and their element ratios are sensitive indicators of source rocks, tectonic setting, paleoweathering condition and A. H. M. Ahmad (*) : R. Agrawal : R. Irshad Department of Geology, Aligarh Muslim University, Aligarh, U.P., India e-mail:
[email protected]
paleoclimate (Bhatia 1983; Condie 1993; McLennan et al. 1993; Jafarzadeh and Hosseini-Barzi 2008; Absar et al. 2009; Raza et al. 2010; Mishra and Sen 2010). Petrography and geochemical study of sedimentary sequences of preserved rocks in the basins serve as a good tool to study the crust building events during ancient time, despite concealment and/ or destruction of source rocks over geological time. In the present study, we report first account of petrography and geochemical data of sandstone succession of Patherwa Formation (Semri Group), Vindhyan Basin to characterize their provenance, and paleoweathering conditions.
Geological setting The U-shaped Vindhyan Basin occurs as a large intracratonic basin on the Bundelkhand craton of Archean-Early Proterozoic age, extending NE-SW from Sasaram to Chittorgarh over an area of more than 100,000 km2. The existing southern margin of the basin in Son Valley exhibits evidence of truncated boundary along which the early Proterozoic Mahakoshal (Bijawar) rocks have been often thrusted over the adjoining Vindhyan strata, as reported by early workers (Yadlekar et al. 1990; Raza et al. 2009) The Vindhyan sediments are generally flat-lying and unmetamorphosed, locally affected by folding and faulting. The basin shows variable thickness exceeding 4,500 m at places in eastern part of the Son Valley implying accumulation of sediments in a subsiding basin (Soni et al. 1987). Gravity and magnetic surveys in the Son Valley have revealed that the Mahakoshal rocks are present under Vindhyans occurring in successive narrow, east-west trending zones (Das 1988). The organic walled microfossils (acritarch) evidences suggest the age range of Vindhyan Supergroup from 1,500 −550 Ma with the presence of major unconformities between
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the various subgroups (Prasad et al. 2005), while radiometric dates suggest the Vindhyan base at 1,721±90 Ma, Rohtas Group as 1,550±40 Ma (Sarangi et al. 2004), and Kaimur Group as 1,140±900 Ma (Vinagradev et al. 1964). The ages of the Rewa and Bhander Groups are well constrained by Vendian marker organic walled microfossils (Prasad 2007) and Ediacaran soft-bodied fossils (De Chirananda 2006) broadly suggest a Neoproterozoic age and overall basin comprises of calcareous, argillaceous and arenaceous sediments deposited in shallow marine environment. The studied Patherwa Formation forms the base of the Son Valley comprising basal sandstone and conglomerates (Fig. 1). The basal sediments rest unconformably upon the Bijawar basement. The lithology and sedimentary structures suggest that the Patherwa Formation was formed dominantly under the influence of tidal processes. In addition to facies association consisting of tidal influenced fluvial channel, tidal channel and tidal sand flat sand bars, these characteristics support a tide-dominated estuarine complex (Ahmad et al. 2012).
Arab J Geosci (2015) 8:1977–1991
Lithology The studied sandstones from four localities are classified into four parts on the basis of grain size. Very coarse-grained sandstones The sandstones of Kewta section is very coarse-grained, yellowish brown in color and moderately sorted. The sandstone is cemented by mainly carbonate and consists of quartz followed by feldspar, rock fragments and mica. The largescale planar cross-bedding and laminations are common. Coarse-grained sandstones Coarse-grained sandstones are common in Dam and Kewta sections. The sandstones are moderately to well sorted, yellowish brown to white color. Large-scale planar, trough, herring-bone cross-beddings (Fig. 2a, b), ripple marks (symmetrical and asymmetrical) and lamination are common. Carbonate, iron, and silica cements are present in the studied sandstones.
Methodology
Medium-grained sandstones
The study is based on the measurement of four stratigraphic sections (Fig. 1). For petrographic and geochemical analysis, samples collected at 50 cm intervals represented the total thickness of the Formation. These samples were studied petrographically after etching and staining for calcite, potash feldspar, and pore spaces. Alizarin Red stain was used for identification of the carbonate cement. For petrofacies analysis, the detrital modes were recalculated to 100 % by summing up total quartz (Qt), monocrystalline quartz (Qm), polycrystalline quartz (Qp), total feldspar (F), total unstable lithic fragments (L), volcanic lithic fragments (Lv), sedimentary lithic fragments (Ls) and total lithic fragments (Lt= L + Qp) framework constituents following Dickinson (1985). Thirty-one samples of sandstones were chosen for geochemical analysis and out of these, 1 sample is very coarse grained, 7 samples are coarse grained, 11 samples are medium grained, and 12 samples are fine grained. The samples were analyzed for their major elements by XRF at National Institute of Oceanography, Goa using bead pellets and trace elements by ICP-MS at National Geophysical Research Institute, Hyderabad. First, we chipped the sample and after that powdered the sample in pulverizer into 20 mesh size. Ultimately, the representative sample was taken after quartering and coning process. Pressed discs made from a 2:3 mixture of powdered sample and binder were analyzed by XRF. The REEs of selected samples were analyzed by ICP-MS.
The sandstones of Markundi, Hardi, and Kewta sections are yellowish brown, reddish brown, and whitish brown in color, medium-grained, well-sorted to moderately sorted. The sandstones consist of abundant quartz followed by feldspar, rock fragments and mica (Fig. 3a, b, c, d). Iron, carbonate, and silica cement are common (Fig. 3e, f). The sedimentary structures include planar and trough cross-beddings, ripple marks, herring-bone cross bedding, and lamination (Fig. 2c, d, e, f). Fine-grained sandstones The fine-grained sandstones belong to Dam, Hardi, and Kewta sections. The sandstones are whitish and yellowish brown in color and moderately to well sorted. The sandstones are cross bedded, ripple bedded, laminated and massive. Iron, silica and carbonate cements are common. The sandstone consists of abundant quartz, feldspar, rock fragments and mica.
Texture and composition The textural and compositional study is based on 60 samples. For quantitative analysis, about 300–400 points per thin section were counted for determining the modal composition of rocks under investigation. The graphic mean size ranges from 0.97 Ø to 3.39 Ø with an average of 2.31 Ø. These sandstones are medium-grained (63 %) followed by fine-grained (28 %), and coarse-grained (9 %) population. Inclusive graphic
Arab J Geosci (2015) 8:1977–1991
Fig. 1 Geological map of the study area
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Fig. 2 Photographs showing a planar cross-bedding, b, c trough cross-bedding, d, e ripple marks, f herring-bone cross-bedding
standard deviation values range from 0.52 Ø to 1.92 Ø (moderately well sorted to moderately sorted). The sand grains are subangular to subrounded with average roundness value of 0.41 and unimodal roundness distribution. The sandstones consist of various types of quartz including plutonic (common quartz), recrystallized metamorphic quartz and stretched metamorphic quartz. These quartz comprise about 90 % of the sandstone composition of which 94 % is represented by monocrystalline and 6 % by polycrystalline grains (Table 1). The monocrystalline variety is mostly nonundulatory and contains inclusions of rutile, zircon, tourmaline, K-feldspars, plagioclase and mica. In polycrystalline quartz variety, intercrystalline boundaries are sharp and straight or highly curved. Some of these grains posses deformed elongated crystal units (tectonites) along which are aligned tiny nonundulatory quartz crystals. A few of the polycrystalline quartz grains are equidimensional having 120° interfacial angle. Feldspars present in these sandstones include plagioclase and K-feldspar (microcline and orthoclase). Both fresh and altered forms of feldspars are common. Alteration and leaching of the feldspar grains is observed along the cleavage plains and grain boundaries. Besides these minerals, tiny and large muscovite flakes occur in the sandstones. Rock fragments observed in these sandstones include chert, shale, schist, phyllite, quartzite, and tuff. Heavy
minerals are opaque, tourmaline, biotite, epidote, garnet, zircon, staurolite, hornblende, and rutile. The studied sandstones are quartzarenitic and subarkosic.
Sandstone petrofacies To understand the tectonic setting of the studied sandstones, the petrofacies were plotted in standard triangular diagrams Qt-F-L, Qm-F-Lt, and Qm-P-K given by Dickinson (1985), and Qp-Lv-Ls modified after Dickinson (1985) and Ingersoll and Suczek (1979) (Fig. 4a, b, c, d). In the Qt-F-L plot, where all quartz grains are plotted together, the emphasis is on grain stability, and thus on weathering, provenance relief and transport mechanism as well as source rocks; while in Qm-F-Lt, where all lithic fragments are plotted together, the emphasis is shifted towards the grain size of source rock, because finegrained rocks yield more lithic fragments in the sand size range. The Qp-Lv-Ls and Qm-P-K plots show only partial grain population but reveal the character of polycrystalline and monocrystalline components of the framework, respectively. In the Qt-F-L (Fig. 4a) diagram, mean detrital modes plot near Qt pole and near Qt-F leg, thereby suggesting a stable, mature craton interior block provenance (Table 2). A
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Fig. 3 Photomicrographs showing a recrystallized metamorphic quartz, b feldspar, c chert grain, d rock fragments, e silica overgrowth, f carbonate cement corroded by iron cement
population shift towards the Qm-F-Lt and F-Lt legs is evident in the Qm-F-Lt diagram (Fig. 4b). This diagram shows that the plot of the data fall in continental block basement uplift provenance with almost equal contribution from recycled orogen provenance. The Qp-Lv-Ls diagram emphasizes lithic
fragments and shows that the studied samples fall in the rifted continental margin (Fig. 4c). The Qm-P-K plot of the data shows that all the sediments contribution is from the continental block basement uplift provenance (Fig. 4d) reflecting maturity of the sediments and stability of the source area.
Table 1 Range and average of textural and mineralogical composition of Patherwa Formation Sandstone, Semri Group, Son Valley, Uttar Pradesh CQ MARKUNDI SECTION Range 75–91 Average 85 KEWTA SECTION Range 79–93 Average 89 DAM SECTION Range 61–84 Average 76 HARDI SECTION Range 68–88 Average 80
VQ
RMQ
SMQ
RF
F
M
Mz
σI
MR
1–3 1
0–12 5
0–8 2
1–3 2
0–8 4
0–2 1
0.97–2.75 1.60
0.52–1.92 0.82
0.32–0.41 0.38
– –
1–5 1
2–10 5
1–3 2
0–5 4
0–4 1
2.05–3.60 2.95
0.70–1.07 0.86
0.38–0.46 40
–
2–19
1–10
1–3
0–8
0–9
1.25–3.10
0.87–2.30
0.42–0.45
–
9
5
2
5
5
2.46
1.73
0.43
0–1 1
2–11 5
0–7 4
1–4 2
4–8 5
0–7 3
0.88–2.50 2.05
0.62–1.40 0.92
0.39–0.44 0.41
CQ common quartz, VQ vein quartz, RMQ recrystallized metamorphic quartz, SMQ stretched metamorphic quartz, RF rock fragments, F feldspar, M mica, Mz graphic mean, σI inclusive graphic standard deviation, MR mean roundness
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Rifted Continental, II Subduction Complex, III Collision suture and fold belt thrust, IV Arc Orogen, in plot d: I Circumpacific volcano plutonic suites, the arrow indicates maturity/stability from continental block provenance margin
Fig. 4 a, b, c, d Qt-F-L, Qm-F-Lt, Qp-Lv-Ls, and Qm-P-K plots of Patherwa Formation Sandstone, according to Dickinson (1985). In plots a and b: Continental Block, I-A Craton Interior, I-B Transitional Continental, I-C Basement uplift, II-A Quartzose, II-B Transitional, II-C Lithic, IIIA Dissected, II-B Transitional, III-C Undissected, IV Mixed, in plot c: I
Table 2 Percentages of framework modes of Patherwa Formation Sandstone, Semri Group, Son Valley, Uttar Pradesh Qt MARKUNDI SECTION Range 91–99 Average 95 KEWTA SECTION Range 93–99 Average 96 DAM SECTION Range 90–99 Average 94 HARDI SECTION Range 89–95 Average 92
F
L
Qm
F
Lt
Qp
Lv
Ls
Qm
P
K
0–8 3
1–4 2
70–91 87
0–8 3
4–16 10
75–93 84
– –
5–25 14
93–100 96
0–4 2
0–5 2
0–5 2
0–3 1
79–90 87
0–5 2
6–17 11
67–94 87
– –
6–33 13
81–10 96
0–12 2
0–8 2
0–8
1–3
61–85
0–8
2–30
83–100
–
4–29
89–100
0–5
0–6
4
2
78
4
18
90
–
10
95
2
3
4–8 6
1–4 2
72–89 82
4–8 6
6–16 12
71–94 86
– –
6–29 14
90–96 93
2–5 3
2–5 4
Qt total quartz, F total feldspar, L total unstable lithic fragments, Qm monocrystalline quartz, Qp polycrystalline quartz, Lv sedimentary/metasedimentary fragments, Lt total lithic fragments, P plagioclase, K orthoclase and microcline
Arab J Geosci (2015) 8:1977–1991
Major elements Major element data indicate that the Patherwa Formation Sandstones are composed almost exclusively of SiO2 (Table 3). Majority of the analyzed samples have CaO, Na2O, and P2O5 concentrations of 0.95) is evident from Zr-Hf diagram as usual and their higher concentration
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points to the derivation of massive sandstones from felsic (mostly granitic rather than mafic, that commonly higher concentrations are observed in felsic rocks than in mafic rocks to ultramafic) rocks. Relationship between mafic components (Cr and Sc) is less clear which may reflect lithological variation in the source rocks. Averages and ranges for high fieldstrength elements (HFSE) and transitional element ratios which are more useful for provenance analysis are shown in Table 3. All lithologies record Cr/Th, Th/Sc and Cr/Zr ratios that are not similar to those of typical Archean Tonalite or transition between Tonalite and basalt for FGS (Cr/Th=3.36, Th/Sc=0.63 and Cr/Zr=0.08), for MGS (Cr/Th=2.4, Th/Sc= 0.84 and Cr/Zr=0.8), for CGS (Cr/Th=11.07, Th/Sc=1.26 and Cr/Zr=0.36) and for VCGS (Cr/Th=1.3, Th/Sc=0.06 and Cr/Zr=0.11) (Table 4) compared with (Cr/Th=6.5, Th/ Sc=1.3 and Cr/Zr=0.3 for Tonalite; Cr/Th=500, Th/Sc=0.02 and Cr/Zr=5.5 for basalt; Condie and Wronkiewicz 1990). Rare Earth Elements Chondrite normalized REE patterns from the Patherwa Formation Sandstone vary systematically in relation to lithology and stratigraphy. FGS and MGS samples are characterized by negative Eu anomaly (Eu/Eu*=0.42–0.88 for FGS and Eu/ Eu*=0.55–0.85 for MGS) and fractionated LREE ((La/ Sm)N =3.55 for FGS and (La/Sm)N =2.55–4.69 for MGS) with almost flat trend is observed for HREEs, from Gd to Lu (Gd/Yb=1.27–2.27 for FGS and Gd/Yb=1.14–2.5 for MGS, Fig. 6a, b, c, d). CGS samples are also characterized by negative Eu anomaly (Eu/Eu*=0.52–0.88). Their patterns indicate fractionated LREE [(La/Sm)n = 4.95] and lessenriched HREE [(Gd/Yb)n=1.64–2.5]. VCGS is characterized by highly fractionated LREE concentration [(La/Sm) n=6.29], negative Eu anomaly (Eu/Eu*=0.40) and decrease trend is observed in HREE concentration [(Gd/Yb)n= 3.77].
Discussion Source area weathering Weathering is required to dislodge the mineral grains from rocks for erosion and sedimentation processes. The extent of weathering defines the nature of the sediments, which is controlled by the climate and tectonics of the hinterland. The most widely used Chemical Index to ascertain the degree of source area weathering is the chemical index of alteration (CIA) proposed by Nesbitt and Young (1982) based on the calculation in terms of molecular proportion: CIA ¼ ½Al2 O3 =ðAl2 O3 þ CaO þNa2 O þ K2 OÞ 100
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Table 3 Average and range of major and trace element concentrations of Patherwa Formation Sandstone
FGS
MGS
CGS
VCGS
Min.
Max.
Avg.
Min
Max.
Avg.
Min.
Max.
Avg.
Avg.
SiO2 (wt%)
56.12
82.9
75.21
64.22
93.26
80.78
56.12
93.26
75.41
76.57
Al2O3 TiO2 Fe2O3 MnO MgO CaO Na2O K2O P2O5 Sc (ppm) V Cr Co Ni Cu Zn Ga Rb Sr
5.79 0.58 1.49 0 0.12 0.15 0 1.61 0.04 2 30 21 10 10 12 8 7 64 29
24.36 1.37 7.78 0.07 3.08 4.17 0.95 3.98 0.24 11 153 77 19 20 42 61 23 108 248
10.23 0.9 4.13 0.01 1.27 0.93 0.28 2.9 0.11 5 64 46 16 16 25 22 11 83 101
1.12 0.09 0.38 0 0.03 0.03 0 0.58 0.01 1 8 20 9 13 15 10 2 21 29
10.52 0.93 3.45 0.12 5.16 12.24 0.3 2.72 0.05 7 62 64 62 22 56 66 12 100 161
4.8 0.34 1.76 0.03 0.95 2.99 0.03 1.89 0.03 3 30 33 24 16 26 24 6 66 74
1.12 0.09 0.38 0 0.03 0.03 0 0.58 0.01 1 8 20 9 10 12 8 2 21 29
24.36 1.37 7.78 0.12 5.16 12.24 0.95 3.98 0.24 11 153 77 62 22 56 66 23 108 248
9.47 0.7 3.16 0.04 1.77 3.42 0.26 2.28 0.08 5 58 44 23 16 29 32 10 73 107
9.86 0.89 0.7 0 0.5 0.17 0.76 0.65 0.02 4 64 58 34 15 111 26 16 48 127
Y Zr Nb Cs Ba Hf Ta Pb Th U La (ppm) Ce Pr Nd Sm Eu Gd Tb
12 253 7 1 193 7 1 1 7 1 25.37 29.93 6.26 23.9 4.72 0.95 4.07 0.73
44 998 30 5 374 44 8 3 44 4 87.1 110.15 20.76 76.22 14.35 3.23 11.79 2.53
21 593 14 3 265 23 3 2 16 2 43.16 54.33 10.83 41.36 7.94 1.7 6.83 1.24
7 205 3 1 150 9 3 1 5 1 11.39 14.76 3.09 11.73 2.16 0.43 1.93 0.36
28 914 23 3 518 40 13 3 41 3 64.46 64.24 15.61 59.03 11.03 1.69 9.58 1.69
16 507 10 2 277 22 6 2 17 2 30.2 36.97 7.54 28.45 5.24 1.04 4.7 0.86
7 205 3 1 150 7 1 1 5 1 11.39 14.76 3.09 11.73 2.16 0.43 1.93 0.36
44 998 30 5 518 44 13 3 44 4 87.1 110.15 20.76 76.22 14.35 3.23 11.79 2.53
21 578 14 2 296 24 6 2 22 2 43.61 51.73 10.68 40.11 7.57 1.51 6.48 1.24
134 534 21 3 263 26 10 4 45 4 662.24 687.44 96.29 382.72 68.02 8.4 59.76 9.9
Dy Ho Er Tm Yb Lu
3.89 0.75 2.09 0.36 2.22 0.36
15.2 2.96 7.96 1.34 7.65 1.19
6.75 1.28 3.59 0.6 3.55 0.57
2.14 0.45 1.22 0.19 1.19 0.18
8.7 1.57 4.2 0.67 3.9 0.63
4.74 0.92 2.57 0.43 2.53 0.41
2.14 0.45 1.22 0.19 1.19 0.18
15.2 2.96 7.96 1.34 7.65 1.19
6.9 1.32 3.61 0.6 3.5 0.56
48.55 8.57 21.06 2.74 13.11 1.82
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Effect of post depositional alteration on sediment geochemistry The concentrations of various elements are affected by various surface processes such as transportation of debris from source to basin, weathering, sorting, metamorphism, and diagenesis. For example, alkali and alkaline earths transported as dissolved species are considered to be mobile elements and thus their abundances in sedimentary rocks may not reflect their profusion in source terrain. However, elements such as Al, Ti, Th, Ni, Cr, Co, Zr, and REE are commonly transported in solid detritus and are reliable indicator of provenance (Taylor and McLennan 1985; Totten and Blatt 1993). Since the sandstones of Patherwa Formation are unmetamorphosed, and do not show any significant effect of surface processes, thus they represent primary geochemical characters of the source rock(s). The geochemical data suggest that the effect of alteration by secondary processes is minimum and this inference is supported by petrographic studies where no alteration effects are noticed in thin sections. The immobile elements can be used as powerful and reliable tools for provenance analysis of Patherwa Formation Sandstone. The relationship between Zr and TiO2 in the Patherwa Formation Sandstone is not strongly positive (r= 0.21) Factors controlling the geochemistry of the Patherwa Formation sandstones
Fig. 5 a Zr plotted against Hf b Zr plotted against Th c Cr plotted against Sc
Where CaO* represents CaO values in silicate fraction only. CIA values of FGS are 60.4–90.5 (avg. 65.16), MGS is 54.36–89.93 (avg. 50.16), and CGS is 62.46–87.18 (avg. 70.92), and one sample of VCGS is 61.55, significantly, suggesting that these sandstones have suffered moderate to slightly intense chemical weathering (Fig. 7). The scattering shown by our data points probably represents a variable degree of weathering in the source terrain. This may be the result of unsteady state weathering conditions where active tectonism and upliftment allow erosion of all soil horizons and rock surfaces (Nesbitt et al. 1996). To further access nature of chemical weathering, geochemical data is plotted in the ACN-K triangular diagram (Fig. 8). In this diagram, all samples are overall plotted above plagioclase-K-feldspar join, indicating moderate to intense chemical weathering in the source area.
Al2O3/TiO2 ratios in igneous rocks generally vary according to rock type, although this is not as sensitive as Cr/Th or Th/Sc (Condie and Wronkiewicz 1990). The Al2O3/TiO2 ratio of felsic igneous rocks is generally >10 and can be >100. Mafic and ultramafic rocks, on the other hand, tend to record ratios 10 (Taylor and McLennan 1985; Condie 1993; Roddaz et al. 2006; Manikyamba et al. 2008; Raza et al. 2010; Fatima and Khan 2012), whereas some are in the range of 20–50, corresponding to felsic rocks, The sandstones of Patherwa Formation, in particular FGS, MGS and CGS are characterized by Al2O3/ TiO2 ratios in the range of 6.2–17.83, 8.62–23.67, and 6.12– 17.08 with the averages of 11.62, 16.21, 10.04 respectively. The VCGS is characterized by Al2O3/TiO2 ratio 11.13. There is no clear relationship between Al2O3 and Al2O3/TiO2 and TiO2 and Al2O3/TiO2 for these groups (Table 3). The comparatively lower values of Al2O3/TiO2 ratios are due to higher
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Table 4 Total REE and some selected geochemical indices for Patherwa Formation Sandstone
n
n
Fine Avg. 180.50 11.62 3.36 3.75 0.08 9.83 182.13 3.55 0.73 1.59 Medium Avg. 152.66
Range 108.35–318.73 6.23–17.83 0.65–7.02 1.38–11.90 0.04–0.16 4.78–23.38 107.04–367.49 2.8–4.25 0.42–.88 1.27–2.27
12 12 12 12 12 12 12 12 12 12
∑REE Al2O3/TiO2 Cr/Th Th/Sc Cr/Zr La/Sc (La/Yb)N (La/Sm)N Eu/Eu* (Gd/Yb)N
Range 51.5–389.85
11
∑REE
Coarse Avg. 92.25 10.04 11.07 3.71 0.36 10.99 98.59 4.38 0.70 2.09 V. Coarse K12-2 2,070.62
Cr/Th
16.21 2.40
8.63–23.67 1.38–3.78
11 11
Al2O3/TiO2 Cr/Th
11.13 1.30
1 1
Th/Sc Cr/Zr La/Sc (La/Yb)N (La/Sm)N Eu/Eu* (Gd/Yb)N
5.76 0.08 11.10 127.44 3.72 0.68 1.57
1.24–7.73 0.02–.21 3.16–15.57 48.04–271.97 2.55–4.69 0.5–.85 1.135–2.50
11 11 11 11 11 11 11
Th/Sc Cr/Zr La/Sc (La/Yb)N (La/Sm)N Eu/Eu* (Gd/Yb)N
12.09 0.11 179.28 2,794.27 6.29 0.40 3.77
1 1 1 1 1 1 1
∑REE Al2O3/TiO2 Cr/Th Th/Sc Cr/Zr La/Sc (La/Yb)N (La/Sm)N Eu/Eu* (Gd/Yb)N
∑REE Al2O3/TiO2
TiO2 concentration as evident from the presence of rutile in thin sections.
Factors controlling REE geochemistry The REE pattern based on the result of the mixing of two end members can be interpreted on: LREE flat pattern and HREE enriched pattern. This interpretation is supported by the relationship between Al2O3, Zr, La, and Yb (Fig. 7a, b, c, d). Lanthanum shows a stronger correlation with Al2O3 (r=0.7) than Zr (r=0.26), while Yb shows no clear correlation with Al2O3 (r=0.43) and Zr (r=0.04). Zircon, an Al free silicate, is the principal host mineral for Zr in sedimentary and igneous rocks, and is common within Patherwa Formation Sandstone samples. Zircon is also major host mineral of HREE with concomitant large negative Eu anomaly. Although there is an increase of ∑REE from VCGS to FGS, then (Gd/Yb)n and (La/Yb)n ratios do not indicate enrichment of HREE. It indicates that despite large concentration of Zr in some of the samples. Zircon was not host mineral for HREE in this sediment. A negative Eu anomaly suggest that zircon contributes significantly to the HREE content of the bulk sediments, this idea is further confirmed by the inverse correlation of (Sm/Yb)n with Zr/Al2O3 (Fig. 9a).
Range 58.39–145.61 6.13–17.07 2.17–24.16 0.84–10.23 0.11–0.65 4.47–22.84 53.33–170.18 3.9–4.95 0.52–.88 1.64–2.5
7 7 7 7 7 7 7 7 7 7
1
Eu anomaly Most of the FGS, MGS, and CGS samples show moderate to low negative Eu anomaly. Nine samples of FGS, five samples of MGS, and four samples of CGS show (Eu/Eu* >0.7), which shows the source to be mafic and TTG. Three samples of FGS, six samples of MGS, and three samples of CGS show (Eu/Eu* 10. The distribution of plots in this diagram (Fig. 10c) indicates that Patherwa Formation Sandstone was derived from a recycled source predominantly felsic in nature with variable but lesser input from mafic rocks. To determine the relative contribution of felsic to mafic input into the sedimentary basin, the data of Patherwa Formation Sandstone are plotted in La-Th-Sc ternary diagram along with available data (Condie 1993) of granite and mafic volcanic rocks (Fig. 11). The plots of samples between fields of granite and mafic rocks suggest a two component mixing model between felsic and mafic end members with variable felsic character. On the basis of petrographic (lighter and heavy minerals) and geochemical data, it may be suggested that the sediments constituting the Patherwa Formation are mainly derived from granite and granodiorite. However, some contribution from mafic rocks is also evidenced from the higher contents of Cr and Sc.
Fig. 10 a Th/Sc plotted against La/Sc, b Eu/Eu* plotted against Th/Sc, c Zr/Sc plotted against Th/Sc
Fig. 11 La-Th-Sc triangular diagram of Patherwa Formation Sandstones. M mafic rocks and G granite (after Condie 1993)
1990
The Vindhyan Basin covers a large part of the northern Indian Shield and rests on a wide variety of basement rocks including the Banded Gneissic Complex in southeastern Rajasthan, and the Bijawar Group, the Chotanagpur Granite Gneiss (CGG) and the Mahakoshal Group in central and western India. The paleocurrent directions for the Vindhyan sediments are mostly northerly and northwesterly (Bose et al. 2001; Ahmad et al. 2012). Therefore, the PaleoproterozoicMesoproterozoic Chotanagpur Granite-Gneiss (CGG) and Bijawar Group composed of granite, granodiorite, pegmatite, gneiss, and volcanic rocks which match with the paleocurrent directions could form provenance for the sediments of the Patherwa Formation.
Conclusions The petrographic and geochemical study of Late Proterozoic Lower Vindhyan Patherwa Formation Sandstone, Son Valley is presented to investigate their provenance and weathering history. The sandstones are mainly quartzarenite and subarkose. The CIA and A-CN-K plot imply that the source rocks were subjected to moderate extents of chemical weathering and the rocks were formed from sediments characterized by recycled input or intensive weathering of the first cycle sediment. The plots on Qt-F-L and Qm-F-Lt diagrams suggest sediment supply from basement granite exhumed in craton interior. The sediments were deposited in rifted basin condition as evidenced by the plot on Qp-Lv-Ls diagram. The Qm-P-K diagram suggests the maturity and stability of the source region. On the basis of geochemical data, the dominant source had continental signatures with a continental material, predominantly felsic in nature consisting of CGG and a minor input from mafic volcanic rich paleoproterozoic Mahakoshal belt. Acknowledgments The authors gratefully thank the Chairman, Department of Geology, Aligarh Muslim University, Aligarh for providing the necessary research facilities. The authors (AHM and RA) are also thankful to the Council of Science and Technology, U. P. for financial help [(CST/AAS/D-2203)].
References Absar N, Raza M, Roy M, Naqvi SM, Roy AK (2009) Composition and weathering conditions of paleoproterozoic upper crust of Bundelkhand Craton, Central India: records from geochemistry of clastic sediments of 1.9 Gwalior Group. Precambrian Res 168:313– 329 Ahmad AHM, Bhat GM, Agrawal R (2012) Facies development and depositional environment of the Patherwa Formation (Semri Group), Son Valley, India. Open J Geol 2:80–90
Arab J Geosci (2015) 8:1977–1991 Al-Harbi OA, Khan MM (2008) Provenance, diagenesis, tectonic setting and geochemistry of Tawil Sandstone (Lower Devonian) in central Saudi Arabia. J Asian Earth Sci 33(3):278–287 Basu A (1985) Influence of climate and relief on composition of sand release at source areas. In: Zuffa GG (ed) Provenance of Arenites. Reidel, Dordrecht, pp 1–18 Bhatia MR (1983) Plate tectonics and geochemical composition of sandstones. J Geol 91:621–627 Bhatia MR, Crook KAW (1986) Trace elements characteristics of greywacke and tectonic setting discrimination of sedimentary basins. Contrib Mineral Petrol 92:181–193 Bose PK, Sarkar S, Chakrabarty S, Banerjee S (2001) Overview of the Meso to Neoproterozoic evolution of the Vindhyan Basin, Central India. Sediment Geol 142:395–419 Byerly GR (1999) Komatites of the Mendon Formation: late-stage ultramafic volcanism in the Barberton Greenstone Belt. Geol Soc Am Bull Spec Publ 329:189–211 Condie KC (1993) Chemical composition and evolution of the upper continental crust: contrasting results from surface samples and shales. Chem Geol 104:1–37 Condie KC, Wronkiewicz DJ (1990) The Cr/Th ratio in Precambrian pelites from the Kaapvaal craton as an index of craton evolution. Earth Planet Sci Lett 97:256–267 Cox R, Lowe DR, Cullers RL (1995) The influence of sediment recycling and basement composition on evolution of mud rock chemistry in the southwestern United States. Geochim Cosmochim Acta 59: 2919–2940 Cullers RL (2000) The geochemistry of shales, siltstones and sandstones of Pennsylvanian-Permian age, Colorado, USA: implications for provenance and metamorphic studies. Lithos 51:181–203 Cullers RL, Padkovyrov VN (2002) The source and origin of terrigenous sedimentary rocks in the Mesoproterozoic Ui group, south-eastern Russia. Precambrian Res 117:157–1183 Das IK (1988) Synergetic interpretation of gravity, magnetic and electrical resistivity data of the Son valley area, unpubl. Report. Geol Sur India 144 p De Chirananda (2006) Ediacaran fossil assemblage in the upper Vindhyans of central India and its significance. J Asian Earth Sci 27:660–683 Dickinson WR (1985) Interpreting relations from detrital modes of sandstone. In: Zuffa GG (ed) Provenance of Arenites. Reidel, Dordrecht, pp 333–361 Fatima S, Khan MS (2012) Petrographic and geochemical characteristics of Mesoproterozoic Kumbalgarh clastic rocks, NW Indian Shield: implications for provenance, tectonic setting and crustal evolution. Int Geol Rev 54:1113–1144 Fedo CM, Eriksson KA, Krogstad EJ (1996) Geochemistry of shales from the Archean (3.0 Ga) Buhwa Greenstone Belt, Zimbabwe: implications for provenance and source-area weathering. Geochim Cosmochim Acta 60:1751–1763 Fralick PW, Kroonberg BL (1997) Geochemical discrimination of clastic sedimentary rock sources. Sediment Geol 113:111–124 Garcia D, Fonteilles M, Moutte J (1994) Sedimentary fractionations between Al, Ti and Zr and the genesis of strongly per aluminous granites. J Geol 102:411–422 Ghosh S, Sarkar S, Ghosh P (2012) Petrography and major element geochemistry of the Permo-Triassic sandstones, central India: implications for provenance in an intracratonic pull-apart basin. J Asian Earth Sci 43(1):207–240 Ingersoll RV, Suczek CA (1979) Petrology and provenance of Neogene sand from Nicobar and Bengal Fans, DSDP sites 211 and 218. J Sediment Petrol 49:1217–1218 Jafarzadeh M, Hosseini-Barzi M (2008) Petrography and geochemistry of Ahwaz Sandstone Member of Asmari Formation, Zagros, Iran: implications on provenance and tectonic setting. Rev mex de cien geol 25(2):247–260
Arab J Geosci (2015) 8:1977–1991 Manikyamba C, Kerrich R, Gonzalez-Alvarez I, Mathur R, Khanna TC (2008) Geochemistry of Paleoproterozoic black shales from the Intracontinental Cuddapah basin, India: implications for provenance, tectonic setting, and weathering intensity. Precambrian Res 162(3):424–440 Mclennan SM, Taylor SR, McCulloh MT, Maynard JB (1990) Geochemical and Nd- Sr isotopic composition of deep sea turbidites: crustal evolution and Plate tectonic associations. Geochim Cosmochim Acta 5:2015–2050 Mclennan SM, Hemming S, Mcdaniel DK, Hanson GN (1993) Geochemical approaches, provenance and tectonics. In: Johnson MJ, Basu A (eds) Processes controlling the compositions of clastic sediments. Geol Soc Am Bull 284:21–40 Mishra M, Sen S (2010) Geochemical signatures of Mesoproterozoic siliciclastic rocks of the Kaimur group of the Vindhyan Supergroup, Central India. J Chin Geochem 29:021–032 Nesbitt HW, Young GM (1982) Early Proterozoic climates and plate motion inferred from major element chemistry of lutites. Nature 299:715–717 Nesbitt HW, Young GM, McLennan SM, Keays RR (1996) Effects of chemical weathering and sorting on the petrogenesis of siliciclastic sediments, with implications for provenance studies. J Geol 10:525–542 Prasad B (2007) Obruchevella and other association organic walled microfossils from the Bhander Group (Vindhyan Supergroup) Madhya Pradesh. J Geol Soc India 69:295–310 Prasad B, Bijai Uniyal SN, Asher R (2005) Organic walled microfossils from the Proterozoic Vindhyan Supergroup of Son Valley, Madhya Pradesh, India. Palaeobotany 54:13–60 Raza M, Khan A, Khan MS (2009) Origin of late paleoproterozoic great Vindhyan basin of north Indian shield: geochemical evidence from mafic volcanic rocks. J Asian Earth Sci 34:716–730 Raza M, Bhardwaj VR, Dayal AM, Rais S, Khan A (2010) Geochemistry of lower Vindhyan clastic sedimentary rocks of northwestern Indian shield: Implications for composition and weathering history of Proterozoic continental crust. J Asian Earth Sci 39:51–61 Rieser AB, Neubauer F, Liu Y, Ge X (2005) Sandstone Provenance of north-western sectors of the intracontinental Cenozoic Qaidam
1991 basin, western China: Tectonic Vs Climatic control. J Sediment Geol 177:1–18 Roddaz M, Viers J, Brusset S, Baby P, Boucayrand C, Herail G (2006) Controls on weathering and provenance in the Amazonian foreland basin: insights from major and trace element geochemistry of Neogene Amazonian Sediments. Chem Geol 22: 31–65 Sarangi S, Gopalan K, Kumar S (2004) Pb-Pb age of earliest megascopic eukaryotic alga bearing Rohtas Formation. Vindhyan Supergroup, India: Implications for Precambrian atmospheric oxygen evolution. Precambrian Res 13:107–121 Shankar R (1993) Structural and geomorphological evolution of “SONATA” Rift Zone in central India in response to Himalayan uplift. J Palaeontol Soc India 38:17–30 Soni MK, Chakraborty S, Jain VK (1987) Vindhyan Supergroup—a review. In: Purana Basin of Peninsular India (Middle to late Proterozoic). J Geol Soc Ind 6:87–138 Sugisaki R, Yamamoto K, Adachi M (1982) Triassic banded cherts in central Japan are not pelagic. Nature 298:644–647 Sugitani K, Horiuchi Y, Adachi M, Sugisaki R (1996) Anomalously low Al2O3/TiO2 values for Archean cherts from the Pilbara Block. Western Australia- possible evidence for extensive chemical weathering on the early earth. Precambrian Res 80:49–76 Taylor, McLennan SM (1985) The Continental Crust: its composition and evolution. Blackwell, Oxford, 311p Totten MW, Blatt H (1993) Alteration in the non- clay mineral fraction of pelitic rocks across the diagenetic to low grade metamorphic transition, Ouachita Mountains, Oklahoma and Arkansas. J Sediment Petrol 63:899–908 Vinagradev A, Tugarinor AL, Zyankov C, Bibikova, E, Khorre K (1964) Geochemistry of Indian Precambrian. 22nd. Internat Geol Cong 10: 553–567 Yadlekar DB, Jain SC, Nair KKK, Dutta KK (1990) The Central Indian collision suture. Geol Surv India Spec Pub 28:1–43 Young GM, Nesbitt HW (1998) Processes controlling the distribution of Ti and AL in weathering profiles, siliciclastic sediments and sedimentary rocks. J Sediment Res 68:448–455
