NORTHERN SEGMENT OF THE PALEOASIAN OCEAN: NEOPROTEROZOIC DEPOSITION HISTORY AND GEODYNAMICS
A.M. Stanevich a , A.M. Mazukabzova, A.A. Postnikovb, V.K. Nemerov c , S.A. Pisarevsky d , D.P. Gladkochub a , T.V. Donskaya a , and T.A. Kornilova a
a Institute of the Earth's Crust, Siberian Branch of the RAS, 128 ul. Lermontova, Irkutsk, 664033, Russia
bInstitute of Petroleum Geology and Geophysics, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
c Vinogradov Institute of Geochemistry, Siberian Branch of the RAS, 1a ul. Favorskogo, Irkutsk, 664033, Russia
dThe University of Western Australia, 35, Stirling Highway, 6009, Crawley, Australia
Pages: 46-60
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.
|
