Contrasting red bed diagenesis the southern and n

Authors: Robert Schöner Reinhard Gaupp

Publish Date: 2005/09/23

Volume: 94, Issue: 5-6, Pages: 897-916

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Abstract

We compare the diagenetic evolution of deeply buried Rotliegend Permian red bed sandstones at the southern and northern margin of the Central European Basin CEB in Germany Main target is to evaluate the influence of maturation products from hydrocarbon HC source rocks during red bed diagenesis At the southern margin of the CEB thick coalbearing Carboniferous source rocks are omnipresent beneath the Rotliegend They contain dominantly gasprone terrigenous organic material and some oil source rocks Hydrocarbons were generated from Late Carboniferous onwards throughout most of basin subsidence At the northern margin of the CEB source rocks are almost absent due to deep erosion of Carboniferous rocks and a low TOC of local Lower Carboniferous relics Early diagenetic processes are comparable at both basin margins Significant differences in burial diagenetic evolution are spatially correlated to the occurrence of hydrocarbon source rocks Burial diagenesis at the southern margin of the CEB is characterized especially by bleaching of red beds major dissolution events pervasive illite formation impregnation of pore surfaces with bitumen and formation of late Ferich cements Almost none of these features were detected at the northern basin margin Instead relatively early cements are preserved down to maximum burial depths This suggests that major diagenetic mineral reactions in deeply buried red bed sandstones are controlled by the presence or absence of maturing hydrocarbon source rocksWe are grateful to DFG for funding this project which is part of the DFG research program 1135 Dynamics of Sedimentary Systems under varying Stress Conditions by example of the Central European Basin System DGMK project 577 This is publication no GEOTECH96 of the program GEOTECHNOLOGIEN of BMBF and DFG We thank ExxonMobil Production Deutschland GmbH and Gaz de France for kindly providing us with core and data material from three deep wells in SchleswigHolstein and for the permission to publish our results We gratefully acknowledge the analytical assistance of Andreas Kronz Göttingen EMP Jens Götze Freiberg cathodoluminscence Günther Völksch Jena SEM and Michael Joachimski Erlangen carbonate isotopes Rebecca Tenorio kindly revised the English manuscript Special thanks are due to Robert Ondrak Potsdam who carefully reviewed an earlier version of the manuscript and to two anonymous reviewers Their constructive comments and suggestions helped to improve this paper

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