THE MIDDLE-UPPER OXFORDIAN BOUNDARY IN THE EAST EUROPEAN PLATFORM

Abstract

The position of the middle-upper Oxfordian boundary in the East European platform (Boreal region) and in the Subboreal and Submediterranean biogeographic provinces is discussed. In order to ensure the boundary isochronism in the Boreal belt, it should be placed between the Amoeboceras alternoides and Amoeboceras ilovaiskii subzones. This proposal means a return to the unified stratigraphic scheme of Mesozoic sediments of 1962. In addition, characteristics of the middle Oxfordian Rat'kovo Formation that is first distinguished in the Upper Jurassic succession of the Moscow syneclise are presented.