TY - JOUR

T1 - Metacarbonate-terrigenous complex of the Derba block (East Sayan)

T2 - petrogeochemical and isotope parameters, metamorphism, and time of formation

AU - Nozhkin, A. D.

AU - Turkina, O. M.

AU - Dmitrieva, N. V.

AU - Travin, A. V.

AU - Likhanov, I. I.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - The Derba block is one of the largest Precambrian terranes of the Sayan-Yenisei accretionary belt in the southwestern margin of the Siberian Platform. It is composed of metamorphosed terrigenous-carbonate rocks of the Sayan Group, injected by granitoids. The geochemical features of gneiss-schist associations indicate the low maturity of their sedimentary protoliths corresponding in composition mainly to graywackes and terrigenous-carbonate rocks (marls). According to the results of U-Pb (LA-ICP-MS) dating of detrital zircons from gneisses and schists, the sedimentary protolith formed in the Vendian. Neoproterozoic subduction complexes were probably the major provenance for terrigenous material, and Early Precambrian rocks made a limited contribution. The Ar-Ar and U-Pb isotope data testify to nearly coeval and multistage events of metamorphism (up to the amphibolite facies) and granitoid magmatism (~ 510-500 and 480-465 Ma) in the Derba block. These processes were reflective of the Early Caledonian orogenic processes in the structures of the Central Asian Orogenic Belt. The similarity in the composition, time of sedimentation, and provenances of metaterrigenous-carbonate complexes of the Derba block (Sayan Group), West Sangilen block of the Tuva-Mongolian massif (Erzin and Moren complexes), and the Khamar-Daban terrane (Slyudyanka Group) suggests that these structures were a single Vendian continental margin with lateral variations in depositional environments and the sources of terrigenous material.

AB - The Derba block is one of the largest Precambrian terranes of the Sayan-Yenisei accretionary belt in the southwestern margin of the Siberian Platform. It is composed of metamorphosed terrigenous-carbonate rocks of the Sayan Group, injected by granitoids. The geochemical features of gneiss-schist associations indicate the low maturity of their sedimentary protoliths corresponding in composition mainly to graywackes and terrigenous-carbonate rocks (marls). According to the results of U-Pb (LA-ICP-MS) dating of detrital zircons from gneisses and schists, the sedimentary protolith formed in the Vendian. Neoproterozoic subduction complexes were probably the major provenance for terrigenous material, and Early Precambrian rocks made a limited contribution. The Ar-Ar and U-Pb isotope data testify to nearly coeval and multistage events of metamorphism (up to the amphibolite facies) and granitoid magmatism (~ 510-500 and 480-465 Ma) in the Derba block. These processes were reflective of the Early Caledonian orogenic processes in the structures of the Central Asian Orogenic Belt. The similarity in the composition, time of sedimentation, and provenances of metaterrigenous-carbonate complexes of the Derba block (Sayan Group), West Sangilen block of the Tuva-Mongolian massif (Erzin and Moren complexes), and the Khamar-Daban terrane (Slyudyanka Group) suggests that these structures were a single Vendian continental margin with lateral variations in depositional environments and the sources of terrigenous material.

KW - Derba block

KW - geochemistry

KW - metamorphism

KW - terrigenous carbonate rocks

KW - U-Pb (LA-ICP-MS) and Ar-Ar dating

KW - SOUTHWESTERN MARGIN

KW - OLKHON REGION

KW - U-PB

KW - WESTERN MARGIN

KW - EVOLUTION

KW - MONGOLIAN MASSIF

KW - ACCRETION

KW - SIBERIAN CRATON

KW - GEOCHEMISTRY

KW - AGE

UR - http://www.scopus.com/inward/record.url?scp=85048162451&partnerID=8YFLogxK

U2 - 10.1016/j.rgg.2018.05.005

DO - 10.1016/j.rgg.2018.05.005

M3 - Article

AN - SCOPUS:85048162451

VL - 59

SP - 652

EP - 672

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 6

ER -