TY - JOUR

T1 - The low-temperature thermo-tectonic evolution of the western Tian Shan, Uzbekistan

AU - Jepson, Gilby

AU - Glorie, Stijn

AU - Konopelko, Dmitry

AU - Mirkamalov, Rustam

AU - Danišík, Martin

AU - Collins, Alan S.

N1 - Publisher Copyright: © 2018 International Association for Gondwana Research

PY - 2018/12/1

Y1 - 2018/12/1

N2 - The Kyzylkum-Nurata region represents a key area in understanding the tectonic evolution of the western Tian Shan. In this study, we present new thermochronological data (apatite fission track and apatite (U-Th-Sm)/He) and associated thermal history models for 45 igneous samples from the Kyzylkum-Nurata Segment of South Tian Shan on the territory of Uzbekistan and Tajikistan. Our data show that the Kyzylkum-Nurata Segment experienced a multi-phase Mesozoic thermal history that differs from previously studied segments of the Tian Shan. A Triassic (~220–200 Ma) cooling signal is widespread throughout the Tian Shan and is interpreted as being associated with exhumation following the closure of the Palaeo-Asian Ocean. Following this period of fast cooling, the Kyzylkum-Nurata Segment experienced a period of slow cooling and erosion in the Early Jurassic (~190–160 Ma). However, in contrast to other parts of the Tian Shan, our study area preserves evidence for rapid cooling during the Late Jurassic–Early Cretaceous (~160–120). Given that this rapid cooling signal was only recorded for samples in association with major structures (e.g., relic suture-shear zones), we interpret this event as a period of fault reactivation related with tectonic processes at the Eurasian margin of the Tethys Ocean. Subsequently, the Late Cretaceous–early Palaeogene (~100–50 Ma) is characterised by slow cooling and erosion. Since the late Palaeogene, the basement of the Tian Shan experienced cooling related to the India-Eurasia collision. The thermal signal of this collision has been extensively recorded in the high-altitude Kyrgyz Tian Shan. Within the low-relief Kyzylkum-Nurata Segment, this Cenozoic overprint is not recorded, allowing for a detailed assessment of the Mesozoic thermal and landscape evolution of the western Tian Shan. Our study demonstrates that the Cretaceous Uzbek Tian Shan was characterised by a series of parallel, linear mountain belts that formed along suture zones during fault reactivation.

AB - The Kyzylkum-Nurata region represents a key area in understanding the tectonic evolution of the western Tian Shan. In this study, we present new thermochronological data (apatite fission track and apatite (U-Th-Sm)/He) and associated thermal history models for 45 igneous samples from the Kyzylkum-Nurata Segment of South Tian Shan on the territory of Uzbekistan and Tajikistan. Our data show that the Kyzylkum-Nurata Segment experienced a multi-phase Mesozoic thermal history that differs from previously studied segments of the Tian Shan. A Triassic (~220–200 Ma) cooling signal is widespread throughout the Tian Shan and is interpreted as being associated with exhumation following the closure of the Palaeo-Asian Ocean. Following this period of fast cooling, the Kyzylkum-Nurata Segment experienced a period of slow cooling and erosion in the Early Jurassic (~190–160 Ma). However, in contrast to other parts of the Tian Shan, our study area preserves evidence for rapid cooling during the Late Jurassic–Early Cretaceous (~160–120). Given that this rapid cooling signal was only recorded for samples in association with major structures (e.g., relic suture-shear zones), we interpret this event as a period of fault reactivation related with tectonic processes at the Eurasian margin of the Tethys Ocean. Subsequently, the Late Cretaceous–early Palaeogene (~100–50 Ma) is characterised by slow cooling and erosion. Since the late Palaeogene, the basement of the Tian Shan experienced cooling related to the India-Eurasia collision. The thermal signal of this collision has been extensively recorded in the high-altitude Kyrgyz Tian Shan. Within the low-relief Kyzylkum-Nurata Segment, this Cenozoic overprint is not recorded, allowing for a detailed assessment of the Mesozoic thermal and landscape evolution of the western Tian Shan. Our study demonstrates that the Cretaceous Uzbek Tian Shan was characterised by a series of parallel, linear mountain belts that formed along suture zones during fault reactivation.

KW - HERCYNIAN POSTCOLLISIONAL MAGMATISM

KW - ASIAN OROGENIC BELT

KW - NORTHERN TIEN-SHAN

KW - FISSION-TRACK

KW - U-PB

KW - INTRACONTINENTAL DEFORMATION

KW - APATITE (U-TH)/HE

KW - TARIM BASIN

KW - EXHUMATION

KW - INDIA

UR - http://www.scopus.com/inward/record.url?scp=85053024630&partnerID=8YFLogxK

U2 - 10.1016/j.gr.2018.08.003

DO - 10.1016/j.gr.2018.08.003

M3 - Article

AN - SCOPUS:85053024630

VL - 64

SP - 122

EP - 136

JO - Gondwana Research

JF - Gondwana Research

SN - 1342-937X

ER -