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GEOREF RECORD

The Sarkhoi Group in East Sayan; Neoproterozoic ( approximately 770-800 ma) volcanic belt of the Andean type

A. B. Kuzmichev and A. N. Larionov
The Sarkhoi Group in East Sayan; Neoproterozoic ( approximately 770-800 ma) volcanic belt of the Andean type
Russian Geology and Geophysics (July 2011) 52 (7): 685-700

Abstract

The Sarkhoi Group localized in the stratotype area is composed of various volcanics and volcanoclastics more than 4 km in total thickness. The volcanics of the lower part are greenschist facies altered rocks ranging from basalt to dacite, and those of the upper part are mainly rhyolitic ignimbrites. The composition, sequence, and facial features of these volcanics show their affinity to the active continental margin. This is confirmed by geochemical data evidencing the participation of the Early Precambrian continental crust in their formation. The U-Pb zircon dating (SHRIMP) of the Sarkhoi volcanics yielded the Neoproterozoic age of the ignimbrites (782+ or -11 Ma, concordant cluster N=8). The tonalite-trondhjemites of the Sumsunur complex in the Gargan block are plutonic analogs of these volcanic rocks. Coeval granitoids were also revealed in other parts of the Tuva-Mongolian and Dzavhan massifs. The approximately 1500 km long Sarkhoi-Dzavhan volcanic belt is a fragment of the Neoproterozoic active continental margin separated from the continent. In the Middle Neoproterozoic, the geodynamic system also included the Oka accretionary prism joining the Sarkhoi continental margin and the Shishkhid island arc. Coeval analogs of the above structures are also reconstructed in the Yenisei Range and Baikal-Muya belt. This suggests that the Sarkhoi belt was initially localized along the margin of the Neoproterozoic Siberian continent. But the exotic origin of the Precambrian massifs in southern Siberia is not ruled out either.


ISSN: 1068-7971
Serial Title: Russian Geology and Geophysics
Serial Volume: 52
Serial Issue: 7
Title: The Sarkhoi Group in East Sayan; Neoproterozoic ( approximately 770-800 ma) volcanic belt of the Andean type
Affiliation: Russian Academy of Sciences, Geological Institute, Moscow, Russian Federation
Pages: 685-700
Published: 201107
Text Language: English
Publisher: Allerton Press, New York, NY, United States
References: 62
Accession Number: 2021-068051
Categories: GeochronologyIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps, 3 tables, sects.
N52°00'00" - N52°00'00", E99°30'00" - E99°30'00"
Secondary Affiliation: All-Russian Research Geological Institute, RUS, Russian Federation
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 202122
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