DOI: 10.1016/j.scib.2021.01.016
论文题名: Initial subduction-related magmatism in southern Alaska identified by geochemistry and zircon Hf-O isotopes
作者: Yang J.-H. ; Wang H. ; Chung S.-L. ; Zhu Y.-S. ; Cole R.
刊名: Science Bulletin
ISSN: 20959273
出版年: 2021
卷: 66, 期: 10 起始页码: 1030
结束页码: 1036
语种: 英语
中文关键词: 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
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 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170469
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Science Bulletin,2021-01-01,66(10)