El Criogénico terminal, el Ediacárico y el Cámbrico temprano en la Plataforma Siberiana sudoccidental: estratotipos y limitotipos

J K Sovetov,L V Solovetskaya

doi:10.3989/egeol.43595.570

Abstract

Se propone a continuación una revisión estratigráfica del Criogénico terminal, el Ediacárico y el Cámbrico temprano en la Platafora Siberiana. Todas las unidades estratigráficas neoproterozoicas tardías llenan la cuenca remanente de Sayan. El registro sedimentario se adscribe al grupo Criogénico terminal y Ediacárico de Oselok y a la formación inferior cámbrica Ust’-Tagul. Se pueden subdividir en miembros a partir de su característico contenido en Dickinsonia.

Highlights

The late Cryogenian, Ediacaran, and lowermost Cambrian sediments described below are located in the foothills of the East Sayan Range in the Iya, Uda, Biryusa, Tagul and Tumanshet river basins, southwestern Siberian Platform
The deeply eroded lower Cryogenian Karagassy Group is discordantly overlain by uppermost Cryogenian glacial, glaciofluvial, and glacial-lacustrine sediments of the Karapchetui member at the base of the Marnya Formation The basal member named after the stratotype Karapchetui locality in the Uda valley fills ≤100 m deep glacial erosion valleys
Deposition during the second Marinoan phase produced the Ulakha Member of black diamictite, which has its stratotype section in the Ulakha creek valley, a tributary of the Uda, and the base limitotype section at the Ozerki locality, where its erosive contact with the Tagul Formation stromatolitic dolomite is exposed in an outcrop

Summary

Introduction

The late Cryogenian, Ediacaran, and lowermost Cambrian sediments described below are located in the foothills of the East Sayan Range in the Iya, Uda, Biryusa, Tagul and Tumanshet river basins, southwestern Siberian Platform. The Oselok Group, with a total thickness of ~2100 m, is divided into distinct cyclic sequences and consists of the Marnya, Uda, and Aisa Formations which, in their turn, comprise several members (Sovetov, 2011). Deposition during the second Marinoan phase produced the Ulakha Member of black diamictite, which has its stratotype section in the Ulakha creek valley, a tributary of the Uda, and the base limitotype section at the Ozerki locality, where its erosive contact with the Tagul Formation stromatolitic dolomite is exposed in an outcrop.

Results

Conclusion