Coalification analysis as a tool for regional geology in the Northern Eifel (Rhenish Massif, Germany)

Abstract

This study is a compilation of regional coalification work which was done in association with geological mapping in the northern part of the Eifel mountains (Devonian, Western Germany). The results are documented and interpreted by using different kinds of two-dimensional presentations: (1) a lateral coalification map, (2) a vertical coalification/stratigraphical height diagram (pseudoborehole), (3) a model cross-section explaining isochronous deviations in coalification. The map shows the highest level of coalification is not restricted to the oldest Palaeozoic strata but includes some sections of Lower Devonian age. The lines of equal coalification cross-geological strata lines that means there is a component of coalification not conformable with simple burial influence. With the help of a pseudoborehole diagram the areal gradient development in different stages of rank is discussed as well as local rapid coalification changes. In a cross-section from the Eifel North–South Zone to the flank of the Venn Anticline, the burial and coalification development is explained by a hypothetical Eifelian sedimentation trough, which marks the time of maximal burial of Lower Devonian strata. Petrophysical influences on coalification of pelitic sediments and the age of coalification are discussed.