Petrology and genesis of Upper Carboniferous seams from the Ruhr region, West Germany

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doi: 10.1016/0166-5162(87)90047-4
Authors:Littke, Ralf
Author Affiliations:Primary:
Ruhr-Univ., Inst. Geol., Bochum 4630, Federal Republic of Germany
Volume Title:International Journal of Coal Geology
Source:International Journal of Coal Geology, 7(2), p.147-184. Publisher: Elsevier, Amsterdam, International. ISSN: 0166-5162
Publication Date:1987
Note:In English. 79 refs.; illus. incl. 13 tables, sketch map
Summary:The petrology of 21 seam profiles of Upper Carboniferous age (Westphalian C and B) has been studied in order to determine their depositional environments and diagenetic history. The youngest profile was drilled at a depth of 790 m and is mainly overlain by Cretaceous sediments. The oldest seam was reached at a depth of 1470 m. The seam thicknesses vary from 0.4 to 2.5 m. The main petrographic compounds are vitrinite, inertinite, liptinite and minerals. The last group occurs as clay bands with illite, kaolinite, minor chlorite and minor quartz contents, or as crack- or-pore-filling calcite, Fe-dolomite, siderite, pyrite, or marcasite, or as syngenetic siderite concretions and pyrite crystals. Three types of profiles are distinguished by their different petrologies. Type I is most abundant, and contains much vitrinite, many clay bands and syngenetic iron sulphides, whereas type III is rich in inertinite and certain characteristic spores. Type II is intermediate but generally contains only low percentages of minerals. Generally, this type is vitrinite-rich in the lower and inertinite-rich in the central and upper parts of the profiles. Spores and other liptinites are much better preserved in all the seams than in clay partings or in siltstones and sandstones above and below the seams. The seams are interpreted to be former autochthonous peats. Type I profiles are probably derived from swamps which were sometimes inundated and covered by overbank deposits. Type II and III seams represent former peats which were not inundated by rivers, and partly grew under the influence of more oxidizing conditions. Therefore, they contain more inertinite and less sulphide and clay bands. They can be interpreted as former raised bogs. Diagenetic changes are expressed as increases of vitrinite reflectances (from 0.65 to 1.0%), and of liptinite reflectances; a red shift of fluorescence spectra of liptinites, increasing amounts of exudatinite (and micrinite) and decreasing amounts of fluorinite and resinite were found. [A.W.H.]
Subjects:Carbonates; Carboniferous; Classification; Clay minerals; Coal; Coal seams; Diagenesis; Economic geology; Macerals; Paleozoic; Reflectance; Sedimentary petrology; Sedimentary rocks; Sheet silicates; Silicates; Sulfides; Upper Carboniferous; Vitrinite; Westphalian; Central Europe; Europe; Germany; North Rhine-Westphalia Germany; Rhine Westphalian Basin; Ruhr; Organic residues; West Germany
Abstract Numbers:87M/6864
Record ID:1989031718
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique
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