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DOI	10.1016/j.scib.2021.01.016
	Initial subduction-related magmatism in southern Alaska identified by geochemistry and zircon Hf-O isotopes
	Yang J.-H.; Wang H.; Chung S.-L.; Zhu Y.-S.; Cole R.
发表日期	2021
ISSN	20959273
起始页码	1030
结束页码	1036
卷号	66 期号:10
英文摘要	Abundant arc-type magmatic and metamorphic rocks exist on Earth today, which provide insights into the equilibrium state of the subduction process. However, magmatic samples generated during the initial stage of subduction is largely unknown. This hinders our understanding of the subduction initiation process and by inference, the onset of plate tectonics as well as the history of crustal formation. To address this issue, we carried out a comprehensive geochemical-geochronological study of a suite of Late Triassic to mid-Jurassic plutonic rocks from southern Alaska that potentially represent magmas from the initial to mature stages of arc formation. While all studied samples show typical arc-type geochemical signatures, i.e., enrichment of large ion lithophile elements (LILEs) and depletion of high field strength elements (HFSEs) relative to the heavy rare earth elements (HREEs), the Late Triassic trondhjemites show unique geochemical features such as strongly positive εHf(t) and εNd(t) coupled with lower δ18O (average 4.77‰ ± 0.09‰). These signatures, along with its higher zircon saturation temperatures compared with younger plutonic rocks, are best explained by shallow partial melting of subducting high-temperature hydrothermally altered lower oceanic crust (i.e., gabbro). If true, these surprising findings would open up new ways to study subduction initiation which would have important bearing on future research on the onset of global plate tectonics and the formation of the continental crust. © 2021 Science China Press
关键词	Arc magmatism Initial subduction Subduction of the Paleo-Pacific oceanic plate Zircon Hf-O isotopes
英文关键词	Geochronology; Hafnium compounds; Metamorphic rocks; Rare earths; Silicate minerals; Tectonics; Zircon; Geochemical features; Geochemical signatures; Heavy rare earth elements; High field strength elements; Large ion lithophile elements; Saturation temperature; Subduction initiation; Zircon Hf-O isotopes; Exploratory geochemistry
语种	英语
来源期刊	Science Bulletin
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207635
作者单位	State Key Laboratory of Lithospheric Evolution, 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; Institute of Earth Sciences, Academia Sinica, Taipei, 11529, China; Department of Geology, Allegheny College, Meadville, PA 16335, United States
推荐引用方式 GB/T 7714	Yang J.-H.,Wang H.,Chung S.-L.,et al. Initial subduction-related magmatism in southern Alaska identified by geochemistry and zircon Hf-O isotopes[J],2021,66(10).
APA	Yang J.-H.,Wang H.,Chung S.-L.,Zhu Y.-S.,&Cole R..(2021).Initial subduction-related magmatism in southern Alaska identified by geochemistry and zircon Hf-O isotopes.Science Bulletin,66(10).
MLA	Yang J.-H.,et al."Initial subduction-related magmatism in southern Alaska identified by geochemistry and zircon Hf-O isotopes".Science Bulletin 66.10(2021).