Pan-African metamorphism and magmatism in the Prydz Belt,East Antarctica:a geochronological perspective

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外文摘要：The Prydz Belt in East Antarctica underwent extensive reworking during the late Neoprotertozoic-early Paleozoic Pan-African orogeny,which is characterized by granulite facies,clockwise P-T paths,and high dT/dP values.This study compiles the existing age and composition data of zircon and monazite from metamorphic rocks and links their key characteristics to the metamorphic evolution of the Prydz Belt.The frequency of zircon U-Pb ages starts to increase noticeably from～555 Ma,peaking between 530 Ma and 520 Ma,followed by a dramatic decline after 520 Ma.High Th/U values(>0.1)of zircon are observed from～545 Ma,displaying a noticeable increasing trend in Th/U values before a rapid decline from～520 Ma.The frequency of monazite ages progressively increases from～540 Ma,reaching its peak at 515 Ma,and then rapidly decreases after 490 Ma.Combined with the crystallization behaviors of zircon and monazite,this study suggests that the systematic changes in Th/U values of zircon after 545 Ma indicate a transition in the thermal regime of the Prydz Belt towards the cooling stage.Abundant growth of zircon and monazite corresponds to the post-peak cooling process,while the crystallization peak of monazite lags behind that of zircon by～5-15 Ma,which indicates a relatively low cooling rate.Though the granitic intrusions accompanied the entire metamorphic evolution,the majority of them are younger than 520 Ma.The results suggest that the Pan-African event likely peaked at～555-545 Ma and gradually cooled to near-solidus conditions at～520-510 Ma,with a relatively slow average cooling process.

外文关键词：

East AntarcticaPrydz BeltPan-African orogenyzirconmonaziteU-Pb dating

作者：

BAO Hong、WANG Wei-(RZ)、LIU Xinshu、ZHAO Yue、GONG Tingnan、LIU Xiaochun、CUI Ying、TIAN Zuolin

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作者单位：

Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China

Key Laboratory of Paleomagnetism and Tectonic Reconstruction,Ministry of Natural Resources,Beijing 100081,China

China University of Geosciences(Beijing),Beijing 100081,China

MOE Key Laboratory of Orogenic Belt and Crustal Evolution,School of Earth and Space Sciences,Peking University,Beijing 100871,China

Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China

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出版年：

2024

DOI：

10.12429/j.advps.2023.0023

极地科学进展(英文版)

中国极地研究中心,国家海洋局极地考察办公室 (Polar Research Institute of China, Chinese Arctic and Antarctic Administration)

极地科学进展(英文版)

影响因子：0.145

ISSN：1674-9928

年,卷(期)：2024.35(2)