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Macrofloral biostratigraphy of the Ottweiler Group in Saar-Lorraine and its consequences for Stephanian palynostratigraphy and geochronology

Cleal C.J.

Studia Geologica Polonica

2008

Vol. 129

9-23

A revised macrofloral biostratigraphy for the Stephanian Ottweiler Group of the Saar- Lorraine Coalfield places most of the succession in the upper Stephanian B Substage (Alethopteris zeilleri Zone). Only the Breitenbach Formation at the top of the Group indicates a position in the middle Stephanian C Substage (Sphenophyllum angustifolium Zone). These revised correlations now make the tonstein date for the Wahlschied Seam, one of the few reliable radiometric dates for the Stephanian Stage, compatible with the recently proposed Carboniferous time scales. It also explains the large time gap at the base of the Holz Conglomerate suggested by the radiometric dates. There is now little evidence that the palynological ST Zone extends lower than the Stephanian B Substage, and that there appears to be a gap in the palynological zonation between the lower Cantabrian and top of the Barruelian Substages.