Northern segment of the Paleoasian Ocean: Neoproterozoic deposition history and geodynamics

Abstract

We suggest new age constraints for regional stratigraphic units and a model of the Neoproterozoic geodynamic evolution of the southern Siberian craton proceeding from our data on genesis and lithology of sedimentary and volcanosedimentary complexes and their correlation combined with published geochronological and chemostratigraphic evidence. Large-scale rifting events in the region may have occurred between 1000 and 850 Ma in the east and between 780 and 730 Ma in the west. The latter time span correlates with the breakup of the Rodinia supercontinent. The interval of 780–680 Ma corresponding to the deposition of the Dalnyaya Taiga regional stratigraphic unit was marked by the onset of collision and the development of an island arc and a back-arc basin in the eastern part of the territory. The basal strata of the Baikal and Oselok Groups and their equivalents presumably deposited at about 730 Ma, and their signature of glacial events correlates with the global Sturtian Glacial. The deposition of the Zhuya unit between 680 and 630 Ma was associated with development of a foreland basin which gave way to a system of orogenic foredeeps in the Early Vendian (since 630 Ma). Our studies furnish new data on the stratigraphy of the Baikal Group and shed more light on its complex structure and ambiguously interpreted deposition sequence.

The Composition and Reconstruction of the Source Area for the Late Precambrian Terrigenous Rocks of the Oselkovaya Series (Biryusa Prisayanie)

“…Оселковая серия, для которой принимается вендский возраст [Sovetov, Komlev, 2005;Letnikova et al, 2013;Sovetov et al, 2015], подразделяется на три свиты: марнинскую, удинскую и айсинскую. Поро-ды оселковой серии исследовались на протяжении многих лет [Dolnik, Vorontsov, 1972;Shenfil', 1991;Sovetov, Komlev, 2005;Sovetov et al, 2015;Sklyarov, 2006;Stanevich et al, 2007;Metelkin et al, 2010;Letnikova et al, 2013;и др. ], при этом наибольшее вни-мание уделялось седиментологическому анализу и литостратиграфическим корреляциям, в меньшей степени проводилось изучение изотопно-геохи-мических и петрофизических свойств этих пород.…”

Lithogeochemistry of Vendian fine-grained clastic rocks in the Nepa-Zhuya region of the Siberian Platform

“…The formation and stratigraphic position of Neoproterozoic sedimentary and volcanosedimentary complexes, which are widespread along the southern periphery of the Siberian Platform, remain debatable for a long time (Semikhatov and Serebryakov, 1983;Ivanov et al, 1995;Chumakov et al, 2007;Stanevich et al, 2007). The Baikal-Patom region hosts the Baikal Complex, which is considered as a standard Siberian Upper Riphean (Baikalian) stratigraphic unit (Kho mentovskii et al, 1985;Khomentovskii, 2002).…”

“…There are different viewpoints on the succession of sedimen tological processes and geodynamic depositional set tings responsible for the formation of Baikalian rocks united into the Patom Complex in the northern periph eral part of the Baikal-Patom region (Chumakov et al, 2007(Chumakov et al, , 2011. The Patom Complex is considered as a succession at the passive continental margin (Chuma kov et al, 2007) or sediments of the Dal'nyaya Taiga and Zhuya time deposited in the back arc basin of the Late Proterozoic Baikal-Patom island arc system (Khomentovskii et al, 2001;Stanevich et al, 2007). The upper part of the complex, which includes the Dal'nyaya Taiga and Zhuya groups (Resheniya …, 1989;Stanevich et al, 2005), is estimated to be either the Late Riphean (780-630 Ma, Stanevich et al, 2007;Nago vitsyn et al, 2004) or Vendian (Sovetov and Komlev, 2005;Letnikova et al, 2006;Raevskaya, 2007, 2008) in age.…”

“…The Patom Complex is considered as a succession at the passive continental margin (Chuma kov et al, 2007) or sediments of the Dal'nyaya Taiga and Zhuya time deposited in the back arc basin of the Late Proterozoic Baikal-Patom island arc system (Khomentovskii et al, 2001;Stanevich et al, 2007). The upper part of the complex, which includes the Dal'nyaya Taiga and Zhuya groups (Resheniya …, 1989;Stanevich et al, 2005), is estimated to be either the Late Riphean (780-630 Ma, Stanevich et al, 2007;Nago vitsyn et al, 2004) or Vendian (Sovetov and Komlev, 2005;Letnikova et al, 2006;Raevskaya, 2007, 2008) in age.…”

“…It is assumed that Archean-Lower Proterozoic complexes developed in inner areas of the Siberian Platform could serve as provenances for the Nepa-Botuoba and Patom paleobasins (Podkovyrov, 2001(Podkovyrov, , 2011Stanevich et al, 2007), while island arc complexes of the convergent Baikal margin of the cra ton provided sedimentary material for the Patom basin in the Dal'nyaya Taiga time (Stanevich et al, 2006(Stanevich et al, , 2007. At the same time, the real contribution of these large provenances into the above mentioned com plexes remains unclear.…”