Title Information

Münchner Geowissenschaftliche Abhandlungen
Reihe A: Geologie und Paläontologie

Volume 14

LUDWIG, Hans Carl: Die Stinkkalke der produktiven Cyrenenschichten Süddeutschlands zwischen Lech und Inn (Egerian) 1988. [in German] – 112 pp., 28 figures, 9 tables, 9 plates, appendix. 29.7 x 21.0 cm. Paperback ISBN 978-3-923871-19-3 Euro 30.00 series: MGA, Reihe A: Geologie und Paläontologie order now

Abstract

The aim of this thesis was to examine the origin of the bituminous limestones occurring as dirt-beds in the Upper Bavarian Pechkohle (bituminous coal). Palaeontological-microfacial analyses, especially geochemical, coal-petrological and petrographic examination methods were applied.

The bituminous limestones most probably developed in the transitional zone between nonflooded swamp forests and open shallow, stagnant water areas from pond up to lake sizes.

The rocks, although appearing regular, can, with the help of different lamination types and differing kerogen contents, be subdivided. It is possible, with reservations, to relate certain bituminous limestone types each to a different depositional environment. Therefore kerogenrich, resp. kerogen-bearing, laminated or laminoidal bituminous limestones arise mainly in the flooded tree-covered resp. with reed and floating leaf plants inhabitated terrestrial-palustrine to palustrial-lacustrine transitional zones. However, non-laminated bituminous limestones with low kerogen content represent deposits of open water areas.

The mineral content of the bituminous limestones consists of mostly pure calcite (1-2 Mol% MgCO₃) with accessory amounts of quartz dolomite, aragonite and pyrite, as well as a slight clay mineral content.

The bituminous limestones show uninterrupted transitions between almost completely kerogen-free and kerogen-rich types (up to 40 Vol%) although the kerogen-type III (mainly from remains of higher developed land plants (Cormophytes) predominates. Only occasionally do the n-alkane distribution substantiate an appreciable participation of algal material in the composition of kerogen. The pristan/phytane relationship, the absence of an infauna, frequent framboidal pyrites, and a constant lamination provide evidence for an oxygen-deficient, even sapropelitic milieu in the depositional environment of the bituminous limestones.