THE ALBIAN-CENOMANIAN BOUNDARY IN THE SOUTHWESTERN CRIMEA

Abstract

Two sections of Albian-Cenomanian boundary beds are studied in the Bakhchisarai area of the southwestern Crimea near the Research-Training Center of the Geological Faculty of the Moscow State University. Ages of lithostratigraphic subdivisions recognized in the sections are substantiated by paleontological data. A hiatus at the Albian-Cenomanian boundary is shown to be insignificant. Distribution of planktonic and some benthic foraminifers in the boundary beds is described for the first time. In terms of micro- and macropaleontological characteristics, the studied beds are well correlative with the new Albian-Cenomanian boundary stratotype (the Mont Risou section located 150 km to the north of Marseilles, Alpes de Haute province of southeastern France) authorized at the Second International Symposium on Cretaceous Stage Boundaries, Brussels, 1995. The ammonite and inoceram faunas coexisting in the Crimean sections enable correlation between fossil assemblages typical of the Tethyan and European paleobiogeographic areas (EPA). After the additional comprehensive study, the sections can be regarded as the eastern standards for the EPA.