THE COMPOSITION AND CONDITIONS OF FORMATION OF THE TERRIGENOUS ROCKS OF CARBONIFEROUS OF THE SIBERIAN PLATFORM
Z. L. Motova1, T. V. Donskaya1, D. P. Gladkochub1, V. B. Khubanov2
a:2:{s:4:"TEXT";s:236:"1Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
2Dobretsov Institute of Geology, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia
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Keywords: Siberian platform, Middle Paleozoic, carboniferous, terrigenous rocks, petrography, geochemistry, detrital zircons, paleogeodynamics
Abstract
We presents new data on the
composition and U-Pb (LA-ICP-MS) age of detrital zircons from terrigenous
carboniferous rocks distributed in the southwestern and central parts of the
Siberian Platform cover, which are associated with the finds of diamonds and
their satellite minerals, are presented. The material characteristics and
analysis of minerals of the heavy fraction of terrigenous rocks of the
Baeronovka formation of the carboniferous studied in the southwestern part of
the platform indicate a predominantly acidic composition of rocks in the source
area. The age of detrital zircons from the sandstone of the Baeronovka
formation suggests rocks of the Sayan area of the basement rocks of the
Siberian Platform, namely Paleoproterozoic granitoids and volcanites of the
Southern Siberian postcollisional magmatic belt as the main sources of detrital
material. In smaller quantities, detrital material entered the sedimentation
basin of the Baeronovka formation due to the destruction of Early Paleozoic
rocks of the northern segment of the Central Asian fold belt. The geochemical
characteristics of terrigenous rocks of the Kata formation and Tushama
formation carboniferous studied in the central part of the Siberian platform indicate
an acidic composition of rocks in the area of their source, however, the
mineral compositions of heavy fractions indicate a different composition of
rocks in the source area. The age of detrital zircons from terrigenous rocks of
the Kata and Tushama formations allows us to consider Neoproterozoic
sedimentary rocks and Middle Paleozoic igneous rocks of the Baikal-Patom zone
of the southern Siberian, as well as Middle Paleozoic igneous rocks of the
Vilyui rift and the Yakut diamond-bearing province as the main sources. The
revealed differences in the composition and age of the rocks of the sources of
detrital material for carboniferous sandstones distributed in different areas
of the Siberian Platform confirm the conclusions of the predecessors about the
existence of several local sedimentary basins in the Devonian-Carboniferous in
the inner regions of the platform, the formation of which was preceded by the
Middle Paleozoic tectonic-magmatic activation, accompanied by diamondiferous
lamproite and kimberlite magmatism.
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