Coniacian to Maastrichtian stage boundaries in the standard section for the Upper Cretaceous white chalk of NW Germany (Lagerdorf-Kronsmoor-Hemmoor): definitions and proposals.

Abstract

Four large quarries in northern Germany provide a continuous section from the Middle Coniacian to Upper Maastrichtian, consisting almost throughout of a white chalk facies. The combined section has a thickness of 570 m. It has been sub-divided biostratigraphically into 33 zones. The vertical ranges of the species of the stratigraphically relevant groups have been determined on the basis of about 30 years of systematic collecting of fossils bed by bed. Belemnites, inoceramids, echinoids, crinoids and brachiopods occur throughout the section, ammonites only in the Campanian and Maastrichtian. The following proposals are put forward for the definition of the stage boundaries: Campanian/Maastrichtian: appearnace of Belemnella lanceolata, nearly coincident with the first occurrence of Hoploscaphites constrictus; Santonian/Campanian; level of phylogenetic development of Conioteuthis granulataquadrata from G. granulata, coincident with the extinction of Marsupites testudinarius; Coniacian/Santonian: appearance of Inoceramus (Cladocermus) undulatoplicatus nearly coincident with the appearance of the Inoceramus pachti/cardissoides group. -Authors