Conodont Zonation of Upper Devonian in Central Europe

ABSTRACT Conodont investigations in the German standard Upper Devonian sections resulted in establishing a conodont zonation. Altogether 26 conodont zones and subzones have been recognized. The conodont succession was obtained mainly from known ammonoid zones beginning with the uppermost Middle Devonian cephalopod zone of Maenioceras terebratum and extending through the entire Upper Devonian into the Wocklumeria Stage. To determine the regional constancy of conodont succession, more than 100 Upper Devonian sections from Germany were studied. The same Upper Devonian conodont succession, recognized in much of Europe, as detailed investigations have subsequently proved. These zones have been found in eastern Germany, Carnic Alps in Austria, Montagne Noire and northern Massif Central in France, Pyrenees and Cantabria in Spain, and Moravia and Bulgaria in southeastern Europe. In addition, in the Belgian Upper Devonian, where the sediments were laid down in a different environment, similar zonal associations and successions coincide with others. Results of studies in the Upper Devonian outside of Europe (mid-western and northern Africa) support the opinion that conodont succession in the Upper Devonian is the same as that in Europe. Presently known deviations are caused by peculiarities within the local geological sequences (breaks in sedimentation, slow deposition, reworking, redeposition, etc.). A recent study of the ammonoid-bearing Upper Devonian sequence of northwestern Australia carried out by Glenister and Klapper indicates that the European conodont zonation also can be applied effectively in this region. Conodonts can be used to zone the Upper Devonian in greater detail than the standard cephalopod succession. Recent studies reveal that boundaries between some ammonoid stages are inexactly defined or that there are gaps in the ammonoid succession. By means of conodonts such gaps may be bridged with the result that the best and most complete biostratigraphic subdivision of the Upper Devonian at present is based on conodonts.