The distribution of Early Callovian foraminifers and ostracods in the Bartolomeevka section (Saratov region): Comparative analysis

Abstract

The distribution of foraminifers in the Lower Callovian Khlebnovka Formation (Gowerianus and Elatmae ammonite Zones) of the Bartolomeevka section (Saratov region) was analyzed along with defining the Haplophragmoides infracalloviensis–Guttulina tatariensis zone that is correlated with ostracod zones and beds. The comparative analysis of the distribution of foraminifers and ostracods through the section with allowance for changes in their diversity and abundance in sediments of the Elatmae Zone revealed two transgressive–regressive cycles. The sediments of both cycles were deposited approximately at the same depths. The older and younger transgressions associated with the Arctic and Tethyan water masses, respectively. The foraminiferal assemblages demonstrate close relationshipships with bathymetry and water temperatures.