TY - JOUR

T1 - Detrital-zircon geochronology and provenance of Ediacaran–Silurian rocks of the central to northern Tajikistan traverse

T2 - Geodynamic implications for the evolution of the Tian Shan

AU - Biske, Yu S.

AU - Ershova, V. B.

AU - Konopelko, D. L.

AU - Stockli, D.

AU - Mamadjanov, Yu M.

AU - Wang, X. S.

N1 - Funding Information: Fieldwork was supported by grant from Saint Petersburg State University № 41126220. We are grateful to Dr. James Barnet for correcting the English language. M. Kurapov and I. Sumareva helped with figure drawing. The valuable comments came from reviewer J. Worthington, anonymous reviewers and associated editor I. Safonova, which all helped us to significantly improve the manuscript. Publisher Copyright: © 2021

PY - 2021/11

Y1 - 2021/11

N2 - The South and Middle Tian Shan form the marginal part of the Central Asian Orogenic Belt (CAOB) and comprise Paleozoic ocean margins, arcs, and Precambrian continental fragments. We use U-Pb dating of detrital zircons from the Ediacaran–Early Paleozoic sedimentary succession, across a south-north transect of the South Tian Shan (STS) fold belt, to show that the Karakum-Tajik Continent (KTC) of the south-western CAOB margin contains an Early to Late Proterozoic nucleus, overprinted by tectono-magmatic events of Ediacaran–Early Cambrian age. Accretionary-type crust formed between ca. 650–500 Ma, while marginal volcanism of the KTC and microcontinents inside the western STS represented the main provenance for clastic sediments deposited within the young Turkestan ocean basin. Abundant zircon grains with ages of 580–500 Ma are widely presented to the north of KTC suggesting a possible connection between the KTC and Baltica through the south-eastern Urals during the Late Ediacaran–Cambrian. The next major zircon cluster of ca. 460–430 Ma, found within sedimentary cover of the KTC, turbidites of its northern margin in the Kurama Range, as well as inside the STS, indicate that these sediments were derived from erosion of Late Ordovician–Early Silurian continental and/or island arcs at the northern margin of the KTC. Numerous accretionary events that occurred during early-middle Paleozoic in the STS were later overprinted by continental collision during the Carboniferous closure of the Turkestan Ocean. The Paleozoic sedimentary cover of the KTC was deformed into an imbricate thrust structure during the Visean, when the Ediacaran–Cambrian Yagnob turbidites were subducted under the KTC to form the matrix of the accretionary complex.

AB - The South and Middle Tian Shan form the marginal part of the Central Asian Orogenic Belt (CAOB) and comprise Paleozoic ocean margins, arcs, and Precambrian continental fragments. We use U-Pb dating of detrital zircons from the Ediacaran–Early Paleozoic sedimentary succession, across a south-north transect of the South Tian Shan (STS) fold belt, to show that the Karakum-Tajik Continent (KTC) of the south-western CAOB margin contains an Early to Late Proterozoic nucleus, overprinted by tectono-magmatic events of Ediacaran–Early Cambrian age. Accretionary-type crust formed between ca. 650–500 Ma, while marginal volcanism of the KTC and microcontinents inside the western STS represented the main provenance for clastic sediments deposited within the young Turkestan ocean basin. Abundant zircon grains with ages of 580–500 Ma are widely presented to the north of KTC suggesting a possible connection between the KTC and Baltica through the south-eastern Urals during the Late Ediacaran–Cambrian. The next major zircon cluster of ca. 460–430 Ma, found within sedimentary cover of the KTC, turbidites of its northern margin in the Kurama Range, as well as inside the STS, indicate that these sediments were derived from erosion of Late Ordovician–Early Silurian continental and/or island arcs at the northern margin of the KTC. Numerous accretionary events that occurred during early-middle Paleozoic in the STS were later overprinted by continental collision during the Carboniferous closure of the Turkestan Ocean. The Paleozoic sedimentary cover of the KTC was deformed into an imbricate thrust structure during the Visean, when the Ediacaran–Cambrian Yagnob turbidites were subducted under the KTC to form the matrix of the accretionary complex.

KW - Arc magmatism

KW - Cambrian

KW - Detrital zircons

KW - Ediacaran

KW - Karakum-Tajik continent

KW - Paleozoic

KW - South Tian Shan

KW - Turbidites

KW - U-Pb dating

UR - http://www.scopus.com/inward/record.url?scp=85112642866&partnerID=8YFLogxK

U2 - 10.1016/j.gr.2021.07.013

DO - 10.1016/j.gr.2021.07.013

M3 - Article

AN - SCOPUS:85112642866

VL - 99

SP - 247

EP - 268

JO - Gondwana Research

JF - Gondwana Research

SN - 1342-937X

ER -