DOI: 10.1038/ngeo2417
论文题名: Slab melting beneath the Cascade Arc driven by dehydration of altered oceanic peridotite
作者: Walowski K.J. ; Wallace P.J. ; Hauri E.H. ; Wada I. ; Clynne M.A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2015
卷: 8, 期: 5 起始页码: 404
结束页码: 408
语种: 英语
Scopus关键词: dehydration
; hydrogen isotope
; island arc
; lithosphere
; magma
; melting
; numerical model
; oceanic crust
; peridotite
; plate tectonics
; slab
; subduction zone
; trace element
; Cascade Range
; Mariana Arc
; Pacific Ocean
; United States
英文摘要: Water is returned to Earth's interior at subduction zones. However, the processes and pathways by which water leaves the subducting plate and causes melting beneath volcanic arcs are complex; the source of the water - subducting sediment, altered oceanic crust, or hydrated mantle in the downgoing plate - is debated; and the role of slab temperature is unclear. Here we analyse the hydrogen-isotope and trace-element signature of melt inclusions in ash samples from the Cascade Arc, where young, hot lithosphere subducts. Comparing these data with published analyses, we find that fluids in the Cascade magmas are sourced from deeper parts of the subducting slab - hydrated mantle peridotite in the slab interior - compared with fluids in magmas from the Marianas Arc, where older, colder lithosphere subducts. We use geodynamic modelling to show that, in the hotter subduction zone, the upper crust of the subducting slab rapidly dehydrates at shallow depths. With continued subduction, fluids released from the deeper plate interior migrate into the dehydrated parts, causing those to melt. These melts in turn migrate into the overlying mantle wedge, where they trigger further melting. Our results provide a physical model to explain melting of the subducted plate and mass transfer from the slab to the mantle beneath arcs where relatively young oceanic lithosphere is subducted. © 2015 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106318
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: 11272 University of Oregon, Department of Geological Science, Eugene, OR, United States; Carnegie Institution of Washington, Department of Terrestrial Magnetism, 5241 Broad Branch Road, Washington, DC, United States; Tohoku University, IRIDeS, 6-6-4 Aoba, Aramaki, Sendai, Miyago, Japan; United States Geological Survey, Volcano Science Center, MS 910, 345 Middlefield Road, Menlo Park, CA, United States
Recommended Citation:
Walowski K.J.,Wallace P.J.,Hauri E.H.,et al. Slab melting beneath the Cascade Arc driven by dehydration of altered oceanic peridotite[J]. Nature Geoscience,2015-01-01,8(5)