气候变化领域集成服务门户(CCPortal): Architecture and P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics

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DOI	10.1016/j.earscirev.2019.102894
	Architecture and P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics
	Tan Z.; Agard P.; Monié P.; Gao J.; John T.; Bayet L.; Jiang T.; Wang X.-S.; Hong T.; Wan B.; Caron B.
发表日期	2019
ISSN	00128252
卷号	197
英文摘要	We present the first comprehensive P-T-deformation-time and kinematic constraints for HP/UHP eclogite, blueschist and greenschist-facies metavolcano-sedimentary rocks cropping out in the Chinese SW-Tianshan metamorphic complex (within the ~30 km wide N-S Akeyazi-Kebuerte area). We reappraise this HP/UHP “mélange”, which should be divided into three main tectonic units, from north to south, according to their discrepant lithologies and P-T-time-deformation histories. These three units crop out in a tectonic window beneath greenschist-facies metavolcanics. P-T estimates point to 1) UHP-LT conditions around 2.6–2.9 GPa at ~520 °C for the metavolcano-sedimentary rocks of the northern HP/UHP unit, 2) HP-LT conditions of 1.8–2.1 GPa and ~500 °C for the central blueschist horizon and 3) lower-blueschist facies conditions of 1.0–1.5 GPa at ~485 °C for the southern ultramafic-mafic unit. In situ laser probe Ar-Ar age constraints (with textural control) on recrystallized phengites from the HP/UHP unit cluster within 315 to 325 Ma. Phengite ages from the central blueschist horizon are 10–15 Ma older, at ~325–345 Ma. Laser-ICP-MS U-Pb dating on zircon from the south ultramafic-mafic unit yield ages around ~360 Ma for metamorphic overgrowths. In contrast, step-heating Ar-Ar phengite age constraints for the greenschist-facies metavolcano-sediments fall within 280–300 Ma. These new field and P-T-time data disclose an episodic exhumation of three main tectonic slices, respectively from ~85 km, ~65 km and ~45 km depths, and a progressive change of metamorphic gradients from ~12 to ~6–7 °C/km, which could reflect a cooling of the subduction system with time. Final juxtaposition at ~20 km was probably achieved around 300 Ma, prior to collision. © 2019 Elsevier B.V.
关键词	40Ar-39Ar in situ laser ablation analyse Chinese SW-Tianshan Cold subduction regime Juxtaposition P-T-deformation-time histories Subduction dynamics UHP/HP metamorphism
英文关键词	argon-argon dating; deformation; P-T conditions; subduction zone; tectonic evolution; time series analysis; ultrahigh pressure metamorphism; ultrahigh temperature metamorphism; uranium-lead dating; zircon; Tien Shan
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203569
作者单位	State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Sorbonne Université, CNRS-INSU, Institut des Sciences de la Terre de Paris, ISTeP UMR 7193, Paris, F-75005, France; Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Insitut Universitaire de France, Paris, F-75005, France; Geoscinces Montpellier, UMR5243, Universite'Montpellier 2, CNRS, Place E. Bataillon, Montpellier CEDEX 05, F-34095, France; Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, Berlin, D-12449, Germany; Laboratory of Isotope Geochemistry, Wuhan Centre of China Geological Survey, Wuhan, 430205, China
推荐引用方式 GB/T 7714	Tan Z.,Agard P.,Monié P.,et al. Architecture and P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics[J],2019,197.
APA	Tan Z..,Agard P..,Monié P..,Gao J..,John T..,...&Caron B..(2019).Architecture and P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics.Earth Science Reviews,197.
MLA	Tan Z.,et al."Architecture and P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics".Earth Science Reviews 197(2019).