DOI: 10.1016/j.precamres.2019.105524
论文题名: Transition of subduction-related magmatism from slab melting to dehydration at 2.5 Ga
作者: Liu H. ; Sun W.-D. ; Deng J.-H.
刊名: Precambrian Research
ISSN: 3019268
出版年: 2020
卷: 337 语种: 英语
英文关键词: Arc felsic rocks
; Archean plate subduction
; Dehydration
; Garnet
; Slab melting
Scopus关键词: Archean
; dehydration
; felsic rock
; garnet
; magmatism
; melting
; plate tectonics
; slab
; subduction
英文摘要: The Archean plate tectonics and subduction-related magmatism have been concerned for several decades. Here we investigate the Archean plate subduction from a new perspective, using the secular records of global-scale non-TTG (tonalite-trondhjemite-granodiorite) felsic rocks with arc-like geochemical affinities. The statistical results show that the La/Yb and Sm/Yb of non-TTG arc felsic rocks evolved at high values in the Archean, and decreased sharply at 2.5 Ga. This abrupt transition indicates a significant change of the petrogenesis. During the Archean, the oceanic crust subducted into the mantle along a high geothermal gradient and reached the conditions of partial melting with garnet stable in the residue, resulting in high La/Yb and Sm/Yb in the arc felsic rocks. As a consequence of the secular cooling of the mantle, the geothermal gradient of a post-Archean subducting cold oceanic crust intersected with the stability limits of hydrous minerals before it reached the wet solidus of basalts, so that the dehydration occurred preferentially and resulted in a drier crust with a much higher temperature of solidus. As such, the post-Archean arc felsic rocks were mostly originated from melting of the hydrated mantle wedge overlying the subducted oceanic slab. The magma source of the arc felsic rocks thereafter became much shallower, corresponding to the low La/Yb and Sm/Yb of those rocks as a consequence of the less stable garnet in the residue. We thus conclude that the subduction-related magmatism changed from slab melting to dehydration model at 2.5 Ga. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/159934
Appears in Collections: 气候变化与战略
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作者单位: Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China
Recommended Citation:
Liu H.,Sun W.-D.,Deng J.-H.. Transition of subduction-related magmatism from slab melting to dehydration at 2.5 Ga[J]. Precambrian Research,2020-01-01,337