Precambrian microfossil-characterized biotopes from the southern margin of the Siberian craton

¹Institute of the Earth's Crust, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
²Institute of Geochemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
³Joint Institute of Geology, Geophysics, and Mineralogy, Siberian Division, Russian Academy of Sciences, Novosibirsk, Russia
⁴State Pedagogical University, Irkutsk, Russia

Abstract

[1]  The microfossils examined in acritarchs from the Neoproterozoic rocks in the southern margin of the Siberian craton have been ecobiologically interpreted. The studied sequences are of particular interest as they represent different sedimentation stages of an evolving marine basin. The conditions of sedimentation were reconstructed and the microfossil assemblages were recognized in three areas of the Sayany-Baikal fold system (SBFS). The ecological and biological affiliation of a part of the organic-walled microfossil morphotypes was revealed owing to the reconstructions and actuopaleontological comparison. Members of green and brown algae, dinoflagellates, and bacteria assemblages from different depths of the paleobasin have been differentiated. Most of organic-walled forms from the SBFS have the property of retaining volume and characters in fossil remains. A modified variant of the acritarch classification is proposed considering this capacity and in an effort to develop in the future a natural classification scheme.

Received 15 November 2005; accepted 21 December 2005; published 28 December 2005.

Keywords: Neoproterozoic, Siberian craton, sedimentation conditions, microfossils, acritarchs, algae, bacteria, classification.

Index Terms: 1023 Geochemistry: Composition of the biosphere; 1055 Geochemistry: Organic and biogenic geochemistry; 1615 Global Change: Biogeochemical cycles, processes, and modeling; 1637 Global Change: Regional climate change.

Citation: Stanevich, A. M., V. K. Nemerov, Yu. K. Sovetov, E. N. Chatta, A. M. Mazukabzov, V. I.  Perelyaev, and T. A. Kornilova (2005), Precambrian microfossil-characterized biotopes from the southern margin of the Siberian craton, Russ. J. Earth Sci., 7, ES6003, doi:10.2205/2005ES000183.