AROMATIC HYDROCARBON COMPOSITION OF THE PERMIAN KUPFERSCHIEFER IN THE LOWER RHINE BASIN, NW GERMANY

The aromatic hydrocarbon composition of 25 samples of Permian Kupferschiefer from the Lower Rhine Basin of NW Germany has been investigated using GC, GC/MS and direct probe MS analysis. Two narrow-sampled profiles were investigated with respect to compositional changes during Kupferschiefer sedimentation and samples from 13 different wells, covering a depth range from 350 to 1000 m, were included in order to study temperature-sensitive variations. In the Kupferschiefer trimethyl-substituted aryl isoprenoids in the range from C-11 to C21 occur. These compounds presumably are degradation products of isorenieratane, which is also present in the extracts. Within the profile the amount of a preferentially occurring C29-chroman increases from the bottom to the top of the Kupferschiefer by a factor of about 2.5. The chroman distribution observed in the Kupferschiefer points towards euhaline to mesohaline seawater during sedimentation. Moreover, in the investigated profiles a terrestrial source input mainly in the bottom-most part of the shale is reflected by the occurrence of a monoaromatic C24-chrysene derivative, presumably derived from ring-A-degradation of pentacyclic triterpenes.