BIOSTRATIGRAPHY OF THE UPPER VENDIAN, LOWER AND MIDDLE CAMBRIAN STRATA IN A SECTION ON THE YENISEI RIVER NEAR PLAKHINSKY ISLAND (northwestern Siberian Platform)
I. V. Korovnikov, S. M. Rovland, V. A. Luchinina, Yu. Ya. Shabanov, and A. V. Fedoseev
Keywords: Stratigraphy, Vendian, Lower and Middle Cambrian, algae, trilobites, small-shell fauna, northwestern Siberian Platform
Pages: 334-342
Abstract
A section is described, which includes the upper part of the Vendian, Lower Cambrian, and lower Middle Cambrian strata. The section is situated on the right bank of the Yenisei River about 5 km downstream from Plakhinsky Island. It has been established that the rocks in the section under study differ signifficantly in lithology from the formations (Izluchina, Sukharikha, Krasny Porog, and Shumny) of the Igarka district typical of this age interval. It is confirmed that a break exists between the Early and Middle Cambrian, which covers the greatest part of the Botomian Age (except the lower part of the Calodiscus-Erbiella Zone) and extends to the Anopolenus henrici-Corynexochus perforatus Zone of the Middle Cambrian Mayaian Age. Abundant remains of the Cambrian fauna have been found and identified: small-shell organisms, trilobites, algae, brachiopods, and gastropods. For the first time this section has been characterized to a sufficient degree. The boundary between the Vendian and Cambrian strata has been drawn, and the entire range of deposits to the Upper Cambrian strata has been stratified.
|
