Original paper
The Ryazanian (basal Lower Cretaceous) standard zonation: state of knowledge and potential for correlation with the Berriasian primary standard
Mitta, Vasily V.
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 286 Heft 2 (2017), p. 141 - 157
published: Nov 1, 2017
ArtNo. ESP155028602001, Price: 29.00 €
Abstract
The chronostratigraphic zonal succession of the ammonoid-based biostratigraphic subdivision of the Ryazanian stage in its type region (the Russian Platform) is discussed. It is proposed to recognize (in ascending order) the Kochi, Rjasanensis, Spasskensis, and Tzikwinianus zones, as the Ryazanian standard. The chronostratigraphic ranges of the genus Riasanites and other ammonites of Tethyan origin in the Rjasanensis and Spasskensis zones apparently correspond to the interval from the Occitanica Zone to the Boissieri Zone (Paramimounum Subzone) of the Berriasian primary standard. The correlation of the basal Lower Cretaceous of the Russian Platform with synchronous beds of Poland, Mangyshlak, Northern Caucasus, Crimea, and direct correlation with the Occitanica Chronozone has promising prospects, making the base of this zone a preferred choice for the Jurassic–Cretaceous boundary. The Central Russian ecotone, therefore, has considerable potential for the Boreal-Tethyan correlation.
Keywords
biostratigraphy • jurassic • ammonites • russian platform • cretaceous • ryazanian • volgian • berriasian