Ein Beitrag zur Gliederung und Abgrenzung des norddeutschen Aptium
published: Mar 15, 1970
Recent work on Aptian strata in some European countries resulted in a new subdivision and a new fixing the limits of this stage. Therefore it seems necessary to discuss the new subdivision and the new boundaries with special regard for the zonation used in Germany up to day. This is only a preliminary note of a paper that will be published in the "Geologisches Jahrbuch" (tome 89) and which contains more details. Opinion is still divided concerning the subdivision of the Aptian. In France three substages are used (Bédoulien, Gargasien and Clansayésien). In most other countries a subdivision in "Lower" and "Upper" Aptian is preferred. But agreement exists between French, English and most Russian workers in placing the boundary Upper Aptian/Lower Albian at the top of the jocobi-zone (or Hypacanthoplites-beds). This is in contrast to the German habit. But the new placing of this boundary is here proposed for Germany too, because this boundary can be easily recognized and is well defined by the first appearence of ammonites of the Leymeriellagroup. Although the Lower-/Upper Aptian-boundary is still under discussion, it may be recommended to follow R. CASEYS (1961) proposals and place it at the top of the Dufrenoya-beds. The boundary Upper Barremian/Lower Aptian is one of the best data lines (E. KEMPER 1967) and therefore should remain unchanged.