sented by index fossils in the Bromberg outcrops are shaded. [E. V. - Early Visean; SE. -Serpukhovian] to fulfil the requirements of the "International Stratigraphic.
Geologica et Palaeontologica
8 Abb.
Marburg, 30. 9. 2003
Medebach-Bromberg, Late Visean (Early Carboniferous) Standard Reference Section of the Rhenohercynian Dieter KORN
with 8 text-figures
·
KORN, Dieter: Medebach-Bromberg, Late Visean (Early Carboniferous) Standard Reference Section of the Rhenohercynian.-Geologica et Palaeontologica 37: 77-88, 8 text-figs.; Marburg, 30. 9. 2003. The Bromberg section near Medebach has the potential for a Standard Reference Section of Late Visean sedimentary rocks in the Rhenish Massif. Ten successive goniatite zones are represented, from the Entogonites grimmeri Zone up to the Neoglyphioceras spirale Zone. The biostrati graphic zonation is paralleled by a lithological subdivision with numerous index horizons with more than 60 tuffitic layers, distinct calciturbiditic beds, and layers with manganocarbonatic as well as phosphatic nodules, which are useful for regional correlation. A lithology-based corre lation between neighboring sections leads to very exact results. The new formation names Hil lershausen, Bromberg, Hesseberg, and Glindfeld Formation are proposed for the Kulmkieselkalk, Kieselige U bergangsschichten, Posidonienkalk, and Kulmtonschiefer. Das Profil am Bromberg bei Medebach hat das Potential fiir ein Standardreferenzprofil fi.ir Sedimentgesteine des Ober-Vise im Rheinischen Schiefergebirge. Zehn aufeinanderfolgende Go niatitenzonen, von der Entogonites grimmeri Zone bis zur Neoglyphioceras spirale Zone sind re priisentiert. Die biostratigraphische Zonierung wird begleitet von einer lithologischen Unter gliederung, die mehr als 60 Tuffit-Horizonte sowie Kalkturbiditbiinke, Mangankarbonat- und Phosphoritknollenlagen einschlieBt. Die auf der Lithologie basierende Korrelation von benach barten Profilen fiihrt zu sehr genauen Resultaten. Die neuen Formationsnamen Hillershausen-, Bromberg-, Hesseberg- und Glindfeld-Formation werden vorgeschlagen fiir den Kulmkieselkalk, die Kieseligen Ubergangsschichten, den Posidonienkalk und die Kulmtonschiefer. Address of the author: Dr. Dieter KORN, Institut fiir Paliiontologie im Museum fiir Naturkunde der Humboldt-Universitiit zu Berlin, InvalidenstraBe 43, D-10115 Berlin, Germany; e-mail
Introduction
Late Visean sedimentary rocks of the Rhenish Massif and the Harz Mountains have long been known for their rich fossil content (KAYSER 1882). Localities such as Aprath and Herborn yielded diverse faunas and belong to the most famous Early Carboniferous fossil Lagerstatten (BRAUCK MANN 1988). The lithostratigraphy and biostratigraphy of the so-called Kulm sediments is rather well-established (Text-fig. 1; see also KORN in AMLER & GEREKE 2002). The Late Visean Kulm succession can be subdivided into at least 15 goniatite zones (KORN 1996, 2002), which are ap plicable in the different facies realms, i.e. the Posidonia Shales, the calciturbiditic formations (such as the Kulmplat tenkalk), and the greywacke sequences. Many outcrops are known to expose long successions of Kulm sediments, but the best outcrop conditions in combi nation with the densest fossil content of the lower half of the Late Visean sedimentary history are found at the aban-
doned quarry on the north-western slope of the Bromberg, 2 west of Medebach (KULICK 1960; NICOLAUS 1963; Text-figs. 2, 3). The rich fossil record of the claystone suc cession, the presence of numerous volcanoclastic layers and other index horizons, as well as the sporadical intercalation of calciturbidite beds make the detailed re-examination of this section challenging. km
The aim of a new research project is to establish a multi stratigraphy of the Rhenohercynian Kulm sediments, prefer ably based on goniatites, trilobites, bivalves, conodonts, spores, as well as lithological features. Correlation of the various sections will be achieved through the use of Graphic Correlation (SHAW 1964). For this reason, the search for possible standard reference sections will be the first accomplishment. The Medebach-Bromberg outcrop fulfils the criteria for such a position among the Rheno hercynian sections. It will be re-introduced in the following study, based on a completely new investigation of the out crop. For this purpose, new formation names are proposed
KORN Medebach-Bromberg, Late Visean Standard Reference Section of the Rhenohercynian
78
goniatite zonation after KORN (1996), KORN & M. HORN (1997); modified Edmooroceras medusa
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Text-fig. 8: Correlation of the Bromberg NW section with the section of the railway cut near Lelbach.
M4 (dark siliceous shales)- 0.45 m; MS (alum shales)-1.65 m; M6 (carbonatic and slightly siliceous shales)- 1.05 m; M7 to M9 (mainly alum shales and the Crenistria Lime stone)-2.50 m.
Units M7 to M9 are regarded here as one unit, representing the maximum flooding surface of the early Late Visean trans . gression (MESTERMANN 1998; HERBIG et al. 1999). In the Waldeck Syncline, the units can be perfectly correlated. (Note that in the Bromberg NW section unit L5 has a thickness of
KoRN Medebach-Bromberg, Late Viseari Standard Reference Section of the Rhenohercynian
86
1.05 m. This contradicts NICOLAUS' section, in which the unit is only 0.41 m. The difference may be due to the fact that NICOLAUS (1963) combined the SOl1thwestern and the north western quarries for the column which he described on p. 17 and figured on pl. 20 to 22.) •
•
•
Calciturbidites: Some of the thin detrital and organic-rich limestone beds of the Medebach-Bromberg section can also be seen in other outcrops, Sl1Ch as Hillershausen and Rhena. Goniatites globostriatus shale: Well preserved fragments of Gon. globostriatus are common in a dark shale 4.30 m above the Grimmeri Bed !lbove metabentonite Jl3. This horizon can also be recognized in other sections. Goniatites crenistria shale: 0.95 m below the Crenistria lime stone, a slightly siliceous shale that contains many crushed specimens of Gon. crenistria can be seen (below metabento nite Jl7).
•
Index horizons: •
•
Hesseberg Formation Type locality: The north-western of the three abandoned quarries
•
at the Bromberg, 2 km east-northeast of Medebach, mapsheet 34 56 4718 Goddelsheim, r 76 925 h 75 400 (Waldeck Syncline). The succession of the outcrop was described in detail by KULICK (1960). Thickness and limits: 12.50 m; separated from the unit below by
a sharp lithological boundary that is characterized by a sudden de crease of the alum shales. The Hesseberg Formation is defined as beginning immediately above the last alum shale horizon imme diately below the double tuffite v 1/v2. Their upper boundary is much more difficult to draw and is defined here by the last car bonatic and fossiliferous claystones, which particularly bear Posi donia becheri and goniatites. Lithology: Most characteristic are fine-bedded, very fossiliferous
claystones with numerous thin (usually 1 to 5 mm in thickness) marly limestone horizons (Text-fig. 7). Within the often laminated shales, coarse-grained limestone beds of 1 up to 55 cm in thick ness are intercalated (Posidonienkalk s_ensu MEISCHNER 1962). Most of these limestone beds contain coarse biodetritus, originat ing from bivalves, brachiopods, cephalopods,·and crinoids. As in the rock unit below, several tuffitic layers can be recognized. Biostratigraphy: The Hesseberg Formation in the Bromberg sec
tion is extremely fossiliferous, and more than 70 single horizons yielded macrofossils, 50 of them with goniatites. Posidonia becheri, which periodically covers bedding surfaces, is the most abundant fossil found in these shales. The second most common macrofossils are the goniatites. Other organisms, including trilo bites, brachiopods, and crinoids are comparatively rare. In gen eral, unequivocal benthic organisms occur infrequently in this rock unit. The Hesseberg Formation is the finest subdivided unit of the Bromberg section. Immediately from the base, goniatites are very common and, despite of their crushed preservation, often easily determinable. Four zones are recognizable from bottom to top: • Goniatites spirifer Zone (2.30 m in thickness): Characterized by the eo-occurrence of Gon. spirifer ROEMER, 1850, Gon. fimbriatus (FooRD & CRICK, 1897), and Paraglyphioceras semistriatum (NICOLAUS, 1963). • Arnsbergites falcatus Zone (2.95 m in thickness): The index Arnsbergites falcatus (ROEMER, 1850) is the most abundant goniatite, but Gon. spirifer and Gon. fimbriatus are still pres ent in the lower two thirds of the zone. • Arnsbergites gracilis Zone (4.10 m in thickness): The index species A. gracilis KORN, 1988 is very common right from the
base of the zone, and is accompanied a little higher by Hiber nicoceras hibernicum MooRE & HopsoN, 1958 and Para glyphioceras sp. Neoglyphioceras spirale Zone (at least 2.40 m of this zone are exposed): Except for the index species Neogl. spirale (PHIL LIPS, 1841), the fauna of the preceding zone persists. Some horizons within the Neogl. spirale Zone yielded only an A. gracilis - Hibernicoceras fauna without the index species.
•
First occurrence of Goniatites spirifer: Gon. spirifer occurs al most immediately after the disappearance of the alum shales above the Crenistria Limestone and helps to mark the base of the Hesseberg Formation. First occurrence of Arnsbergites falcatus: In high frequency, A. falcatus is present in a laminated shale at the beginning of its stratigraphic distribution. The occurrence was already men tioned by KULICK (1960) as "Falcatus-Bank". Immediately below this horizon is a 9 cm thick alum shale, which is also a resional index horizon. Tuffitic layers: Compared to the Hillershausen and Bromberg Formations, the number of tuffitic layers decreased in the Hesseberg Formation. The most conspicuous of these, the "Beddelhauser Tuff', is a 0.20 m thick coarse-grained crystal tuff that contains large muscovite crystals. Its position is 5.60 m above the Crenistria Bed in the A. falcatus Zone. Calciturbidites: Within the Hesseberg Formation, more than 25 calciturbidite horizons of 1 cm up to 55 cm thickness can be counted. Some of the beds are at least regionally distrib uted (MEISCHNER 1962) and can be traced in other outcrops of the Waldeck Syncline.
Glindfeld Formation Type locality: The north-western of the three abandoned quarries
at the Bromberg, 2 km east-northeast of Medebach, mapsheet 34 56 76 925 h 75 400 (Waldeck Syncline).
4718 Goddelsheim, r
Thickness and limits: Only the basal ten meters of the formation
are exposed at the Bromberg site (Text-fig. 7). The boundary of the preceding rock unit is gradual. The Glindfeld Formation, which is rarely well exposed in the vicinity of the Bromberg, begins after the disappearance of the laminated claystones, which are typical for the Hesseberg Formation. This coincides with the offset of the· calciturbiditic beds. Lithology: The Glindfeld Formation at Bromberg is a very mo
notonous unit, composed of only gray claystones with low mica content. Only a few thin (1 to 2 cm thick) carbonate horizons are intercalated. Biostratigraphy: Fossils are extremely rare, and only a few spec
imens of Posidonia becheri have been collected. Therefore it is unclear which goniatite zones are represented in this unit. Accord ing to KULICK (1960), "Neoglyphioceras subcirculare" occurs 4 m north of the quarry wall. This record cannot be confirmed.
Correlation of sections
Biostratigraphic as well as lithostratigraphic features can be used for correlation with other sections. As is exemplified in Text-fig. 8, a comparison with the Rhena-Lelbach section 12 km northeast of the Bromberg, the Bromberg Formation and lower part of the Hesseberg Formation can be perfectly correlated. The example of the Bromberg Formation demonstrates that for correlation of approximately 12.50 m of sedimen-
KoRN Medebach-Bromberg, Late Visean Standard Reference Section of the Rhenohercynian
tary rocks, approximately 60 points of correlation can be counted, leading to an extremely exact correlation between neighboring sections. The same number of points of corre lation may be available within the Hesseberg Formation.
Prospects
•
•
This investigation demonstrates the high potential of the Kulm succession for subdivision and correlation of sections on an extremely detailed scale. Correlation, however, was at first only achieved by using lithological and a limited num ber of biostratigraphic features (goniatites in this case). Fur thermore, correlation of a limited part of the Late Visean rock sequence was done between closely spaced section. Further investigations will focus on the following topics: •
•
Lithological correlation of sections within the upper part of the Hillershausen Formation, including the calcitur biditic time equivalent Hellefeld Formation from the northern margin of the Rhenish Massif.
• •
87
Lithological correlation of sections within the Hesseberg Formation and their carbonatic (Kulmplattenkalk and Rhenaer Kalk) and siliciclastic time equivalents. Incorporation of other fossil groups such as trilobites, bivalves, conodonts, foraminifers, and palynomorphs in subdivision and correlation of rock bodies. Formation of a comprehensive data base (Composite Standard Section) of all possible litho- and biostrati graphic features of the Late Visean and earliest Namur ian sedimentary successions of the Rhenish Massif and Harz Mountains. Interregional correlation of Late Visean sections. Absolute dating of some of the tuffitic layers and estab lishment of an Early Carboniferous time scale. Acknowledgements
The study was funded by the Deutsche Forschungsgemeinschaft, project number Ko 1829/1. I am indebted to Jennifer Clark and Elizabeth Bickford (Tiibingen, Seattle) for checking the text.
Literature AMLER, Michael R.W. & GEREKE, Manfred (eds.)(2002): Karbon Korrelationstabelle (KKT) - Carboniferous Correlation Table (CCT).- Senckenbergiana lethaea 82 (2): 691-709, tabs. 1-32; Frankfurt/M. BRAUCKMANN, Carsten (1982): Schichtfolge und Fossilfiihrung im oberen Kulm (Unterkarbon cu Ill) von Riescheid in Wup pertal (Bergisches Land). - Jahresberichte des Naturwissen schaftlichen Vereins in Wuppertal 35: 79-88, text-figs. 2-6; Wuppertal. BRAUCKMANN, Carsten (1988): Das Unterkarbon von Aprath im Bergischen Land.-In: WEIDERT, Wemer K. (ed.): Klassische Fundstellen der Palaontologie 1: 27-32, lO text-figs.; Korb (Goldschneck-Verlag). BRi.JNING, Kurt (1923): Beifrage zur Kenntnis des Rheinisch-west falischen Unterkarbons, insbesondere der Goniatiten und Ko rallen in der stratigraphischen Stellung und Gliederung. - 59 p., 18 text-figs.; Marburg. GURSKY, Hans-Jiirgen (1997): Die Kieselgesteine des Unterkar bons im Rhenoherzynikum. Sedimentologie, Petrographie, Geochemie und Palaozeanographie. - Geologische Abhand lungen Hessen 100: 1-117, text-figs. 1-24; Wiesbaden. HAUBOLD, Wemer (1933): Ueber das Unterkarbon auf Blatt God delsheim am Ostrande des Rheinischen Schiefergebirges. Jahrbuch der PreuBischen Geologischen Landesanstalt (for 1932) 53: 208-246, pi. 18; Berlin. HEDBERG, Hollis D. (1976): International Stratigraphic Guide (A Guide to Stratigraphic Classification, Terminology and Pro cedure).- xx + 200 p.; New York (Wiley). HERBIG, Hans-Georg, KORN, Dieter & MESTERMANN, Bemd (1999): Crenistria event and Asbian-Brigantian Transition in the South Portuguese Zone - Sea Level Control on a Hemi pelagic Late Dinantian Platform. - Fazies 41: 183-196, text figs. 1-4, pis. 41-42; Erlangen. HORN, Manfred (1960): Die Zone des Eumorphoceras pseudobi lingue im Sauerland. - Fortschritte in der Geologie von
Rheinland und Westfalen 3 (1): 303-342, text-figs. l -6, tab. 1, pis. 1-5; Krefeld. Hoss, Hildegard (1957): Untersuchungen iiber die Petrographie kulmischer Kieselschiefer. - Beitrage zur Mineralogie und Petrographie 6: 59-88, text-figs. 1-13, tabs. 1-20; Gottingen. JACKSON, Peter J. (1985): Sedimentology, stratigraphy and parae oceanography of some Lower Carboniferous hemipelagic sequences. - Ph.D. Thesis University of Oxford. -292 p., 50 text-figs., 6 pis.; Oxford (unpublished). JACKSON, Peter J. (1990): The Crenistria-Limestone: Parae oceanographic crisis in a Dinantian sea.-Neues Jahrbuch fiir Geologie und Palaontologie, Monatshefte 1990 (10): 607-621, text-figs. 1-6; Stuttgart. KAYSER, Emanuel (1882): Beitrage zur Kenntnis von Oberdevon und Culm am Nordrande des Rheinischen Schiefergebirges. Jahrbuch der Koniglich Preussischen Geologischen Landes anstalt 1881 (2): 51-91, pis. 1-3; Berlin. KoBOLD, Albrecht (1933): Die Gliederung des Oberharzer Kulms nach Goniatiten. Stratigraphische Beobachtungen im Kulm des nordwestlichen Oberharzes unter besonderer Beriicksich tigung der Grauwacken. - Jahrbuch der PreuBischen Geologi schen Landesanstalt (for 1932) 53: 450-515, text-figs. 1-3, tabs. 1-4, pis. 22-23; Berlin. KoRN, Dieter (1996): Revision of the Late Visean goniatite strati graphy. -Annales de la Societe Geologique de Belgique 117 (1): 205-212, text-figs. 1-3; Bruxelles. KoRN, Dieter (2002): Column B011cm02: Ammonoideen-Zonen und Geno-Zonen. - In: AMLER, Michael R.W. & GEREKE, Manfred (eds.): Karbon-Korrelationstabelle (KKT) -Carbon iferous Correlation Table (CCT). - Senckenbergiana lethaea 82 (2): 695; Frankfurt/M. KoRN, Dieter & HoRN, Manfred (1997): Subdivision of the basal Early Narnurian (Early Carboniferous) in the Rhenish Massif (Germany). - Newsletters on Stratigraphy 35 (2): 115-126, text-figs. 1-5, tab. 1; Berlin, Stuttgart.
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KORN Medebach-Bromberg, Late Visean Standard Reference Section of the Rhenohercynian
KULICK, Jens (1960): Zur Stratigraphie und Palaeogeographie der Kulm-Sedimente im Eder-Gebiet des nordostlichen Rheini schen Schiefergebirges. - Fortschritte in der Geologie von Rheinland und Westfalen 3 (1): 243-288, text-figs. 1-11, tabs. 1-3, pl. 1; Krefeld.
SALVADOR, Amos (1994): International Stratigraphic Guide (A Guide to Stratigraphic Classification, Terminology and Proce dure), 2"d ed. - xix + 214 p.; Trondheim (International Union of Geological Sciences and Geological Society of America). SCHMIDT, Hermann (1925): Die carbonischen Goniatiten Deutsch lands. - Jahrbuch der PreuBischen Geologischen Landes anstalt (for 1924) 45: 489-609, text-figs. 1-3, pls. 19-26; Berlin.
MEISCHNER Klaus-Dieter (1962): Rhenaer Kalk und Posidonien kalk im Kulm des nordostlichen Rheinischen Schiefergebirges und der Kohlenkalk von Schreufa (Eder). - Abhandlungen des Hessischen Landesamtes fiir Bodenforschung 39: 1-47, text figs. 1-15, tabs. 1-2, pls. 1-7; Wiesbaden.
SHAW, Alan B. (1964): Time in stratigraphy. - 365 p.; New York (McGraw-Hill).
MESTERMANN, Bernd (1998): Mikrofazies, Paliiogeographie und Eventgenese des crenistria-Horizontes (Obervise, Rhenoher cynicum). - Kolner Forum fiir Geologie und Paliiontologie 2: 1-77, text-figs. 1-14, pls. 1-8; KOln.
WARNKE, Klaus (1997): Microbial carbonate production in a starved basin: The crenistria Limestone of the upper Visean German Kulm facies. - Palaeogeography, Palaeoclimatology, Palaeoecology 130: 209-255, text-figs. 1-10; Amsterdam.
NEBE, Balduin (1911): Die Culmfauna von Hagen i.W., ein Bei trag zur Kenntnis des westfiilischen Untercarbons. - Neues Jahrbuch fiir Mineralogie, Geologie und Paliiontologie, Bei lage-Band 31: 421-495, pls. 12-16; Stuttgart.
WEIGELT, Johannes (1919): Die Gliederung und die Faunenver teilung im Unteren Culm des Oberharzes. - Jahrbuch der Ko niglich PreuBischen Geologischen Landesanstalt (for 1916) 37 (2): 157-271, pis. 9-15; Berlin.
NrcoLAUS, Hans-Joachim (1963): Zur Stratigraphie und Fauna der crenistria-Zone im Kulm des Rheinischen Schiefergebirges. Beihefte zum Geologischen Jahrbuch 53: 1-246, text-figs. 132, tabs. 1-15, pls. 1-22; Hannover.
WITTEN, Wolfgang (1979): Stratigraphie, Sedimentologie und Pa liiogeographie der Kieselkalke im Unterkarbon Ily/8 bis Ilia des nordostlichen Rheinischen Schiefergebirges. - Geologi sche Abhandlungen Hessen 80: 1-132, text-figs. 1-26, tab. 112, pis. 1-4; Wiesbaden.
RUPRECHT, Leo (1937): Die Biostratigraphie des obersten Kulm im Sauerlande. - Jahrbuch der PreuBischen Geologischen Landesanstalt (for 1936) 57: 238-283, text-figs. 1-18, pls. 910; Berlin.
Manuskript-Eingang am 9. 6. 2002. Revidiertes Manuskript zum Druck angenommen am 28. 6. 2003.
