首页|SS-LASS Zircon Dating Deciphering Multiple Episodes of Anatexis in a Deeply-Subducted Continental Crust:An Example from Sulu Orogen, China

SS-LASS Zircon Dating Deciphering Multiple Episodes of Anatexis in a Deeply-Subducted Continental Crust:An Example from Sulu Orogen, China

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'Single shot' laser-ablation split-stream (SS-LASS) technique analyzing unpolished zircon grains makes their thin rims tenable for determination, which thus offers great potential in deciphering the timing of multiple and short-lived episodes of anatexis and metamorphism in deeplysubducted continental crusts. Dominated granitic gneisses in the deeply subducted continental crust undergoing considerable fluid-melt activities persist multistage growth of zircon. Therefore, a comparative study of SS-LASS and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) zircon dating was conducted on the granitic gneisses from the Sulu belt in this study. Zircons mostly show a core-mantle-rim structure with CL-bright rims thinner than 5 μm. For LA-ICP-MS dating, relict magmatic zircon cores yield protolith ages of ca. 756-747 Ma; whereas the dark mantles record synexhumation anatexis at ca. 214 Ma. By contrast, according to the U-Pb dates, trace element features, zircon crystallization temperatures and geological context, SS-LASS zircon petrochronology deciphers three episodes of anatectic events, as follows: (i) the first episode of anatexis at ca. 218-217 Ma dominated by phengite-breakdown melting, likely facilitating the exhumation of the UHP slice from mantle depth; (ii) the second episode of anatexis at ca. 193-191 Ma indicating part of northern Dabie-Sulu belt was still "hot" because of buried in the thickened orogenic crust at that time; (iii) the third episode of anatexis (ca. 162-161 Ma) consistent with the intrusion ages (ca. 161-141 Ma) of the Jurassic to Cretaceous granitoids in this orogen, suggesting the initial collapse of the orogenic root of the Sulu belt occurred at Late Jurassic due to the Izanagi plate initially subducting beneath the margin of Eastern Asia. This study sheds new light upon the utilization of SS-LASS petrochronology deciphering multiple anatectic events in the deeply-subducted continental crust and supports us in better understanding the tectonic evolution of Dabie-Sulu Orogen.

anatexislaser ablationlaser-ablation split-streamultrahigh-pressure metamorphic beltSulu Orogen

Peng Feng、Lu Wang、Xiawen Li、Wenjie Ding、Zhe Chen

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School of Resource & Environment and Safety Engineering,University of South China,Hengyang 421001,China

State Key Laboratory of Geological Processes and Mineral Resources,Center for Global Tectonics,School of Earth Sciences,China University of Geosciences,Wuhan 430074,China

No. 8 Institute of Geology and Mineral Resources Exploration of Shandong Province,Rizhao 276826,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaChina Postdoctoral Science FoundationChinese Ministry of EducationMost Special FundMost Special FundOpen funds from the State Key Laboratory of Geological Processes and Mineral Resources,China University of GeosciencesOpen funds from the State Key Laboratory of Geological Processes and Mineral Resources,China University of GeosciencesOpen funds from the State Key Laboratory of Geological Processes and Mineral Resources,China University of GeosciencesFundamental Research Funds for National University

420722284210206041902036415721822021M692983BP0719022MSFGPMR02-3MSFGPMR30GPMR201703GPMR201704GPMR201903CUG-G1323511572

2024

10.1007/s12583-022-1797-8

地球科学学刊(英文版)
中国地质大学

地球科学学刊(英文版)

CSTPCD
影响因子：0.724
ISSN：1674-487X
年,卷(期)：2024.35(1)
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