Re-assessment of ammonoid specimens from the Early Carboniferous Protocanites Beds of the Badenweiler–Lenzkirch Zone (Schwarzwald, Central Variscan Belt): age constraints for a lithostratigraphic key bed

Dieter Korn,Michael Montenari

doi:10.1007/s12542-021-00577-4

Abstract

The Protocanites Beds of the Black Forest Massif (Germany) form an important lithostratigraphic key bed, as the index fossils contained in this formation enable correlation within large areas of the internal zone of the central Variscan Belt of Europe. Furthermore, the formation provides significant information on the geodynamic evolution of the Moldanubian Zone. The stratigraphic age of the formation has been a subject of controversy in the past; a Devonian to Viséan age has been proposed. To determine the age of the Protocanites Beds, two ammonoid specimens from the Protocanites Beds of Schönau are re-described here. They belong to Becanites abnobensis and Pericylcus princeps and fix the stratigraphic position of the Protocanites Beds to the early Late Tournaisian.

Highlights

Deciphering the geological framework within the internal zone of the central European Variscan Belt is very difficult, as reliable biostratigraphic age determinations are rare and lithostratigraphic correlation is often questionable due to the lack of unambiguous marker beds and intensive tectonic dislocations
One of the scarce marker horizons within the Moldanubian Black Forest Massif is the Protocanites Beds with their type locality at the city of Schönau im Wiesental; this formation was proven to serve as a lithostratigraphic key
1997, 1998) led to a plate tectonic model (Loeschke et al 1998) for the Moldanubian Black Forest Massif, in which the Badenweiler–Lenzkirch Zone was interpreted as a major Variscan suture Zone

Summary

Introduction

Deciphering the geological framework within the internal zone of the central European Variscan Belt is very difficult (for the latest review, see Franke et al 2000), as reliable biostratigraphic age determinations are rare and lithostratigraphic correlation is often questionable due to the lack of unambiguous marker beds and intensive tectonic dislocations. One of the scarce marker horizons within the Moldanubian Black Forest Massif is the Protocanites Beds with their type locality at the city of Schönau im Wiesental; this formation was proven to serve as a lithostratigraphic key. The Protocanites Beds were interpreted as Early Carboniferous in age (Burgath and Maass 1973; Güldenpfennig 1997 with additional references therein; see Sittig 1961).

Results

Conclusion