AROMATIZED ARBORANE FERNANE HYDROCARBONS AS MOLECULAR INDICATORS OF FLORAL CHANGES IN UPPER CARBONIFEROUS LOWER PERMIAN STRATA OF THE SAAR-NAHE BASIN, SOUTHWESTERN GERMANY/

Thirty-seven coal samples of Upper Carboniferous and Lower Permian age from three boreholes in the Saar-Nahe Basin, Germany, have been studi ed by organic geochemical and coal petrological methods. The investiga tions were aimed at the recognition of floral changes in the Upper Car boniferous and Lower Permian strata. The results show that composition al changes in the extracts are only partly caused by variations in coa lification. Specific aromatic hydrocarbons appear in Upper Westphalian D coal seams and increase in concentration up to the Rotliegendes. Th e dominant compound has been identified by mass spectrometry and NMR-s pectroscopy as 5-methyl-1 thylpentyl)-des-A-25-norarbora(ferna)-5,7,9- triene (MATH) and always occurs associated with 25-norarbora(ferna)-5, 7,9-triene. Both compounds are thought to originate from isoarborinol, fernene-3 beta-ol, or fernenes. The strongly acidic conditions during deposition of the coals might have induced the 4,5-cleavage combined with a methyl-shift in an arborane/fernane-type pentacyclic precursor yielding the MATH. Based on petrological investigations, palynomorphs related to early Gymnospermopsida such as Pte- ridospermales and Conif erophytes (Cordaitales and Coniferales) increased in abundance in the strata beginning with the Upper Westphalian D concomitant with the abo ve mentioned biomarkers. The results suggest the arborane/fernane deri vatives originate from the plant communities producing these palynomor phs.