DOI: 10.1016/j.epsl.2019.116000
论文题名: Stability and migration of slab-derived carbonate-rich melts above the transition zone
作者: Sun Y. ; Hier-Majumder S. ; Xu Y. ; Walter M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 531 语种: 英语
中文关键词: carbonate-rich melts
; low-velocity layer
; reactive porous flow
; transition zone
; volatile cycle
英文关键词: Carbon
; Diamond deposits
; Freezing
; Solvents
; Stability
; Concentration-dependent
; Geochemical evidence
; Low velocity layers
; Mantle transition zone
; Porous flow
; Theoretical modeling
; Transition zones
; volatile cycle
; Carbonation
; carbonate
; geochemistry
; low velocity zone
; numerical model
; partial melting
; petrology
; porosity
; slab
; stability analysis
; tectonic setting
; transition zone
英文摘要: We present a theoretical model of the stability and migration of carbonate-rich melts to test whether they can explain seismic low-velocity layers (LVLs) observed above stalled slabs in several convergent tectonic settings. The LVLs, located atop the mantle transition zone, contain small (∼1 vol%) amounts of partial melt, possibly derived from melting of subducted carbonate-bearing oceanic crust. Petrological and geochemical evidence from inclusions in superdeep diamonds supports the existence of slab-derived carbonate melt, which may potentially explain the origin of the observed melt in the LVL. However, the presumptive reducing nature of the ambient mantle can be an impediment to the stability of carbonated melt. To reconcile this apparent contradiction, we test the stability and migration rates of carbonate-rich melts atop a stalled slab as a function of melt percolation, redox freezing, amount of carbon supplied by subduction, and the metallic Fe concentration in the mantle. Our results demonstrate that carbonate-rich melts in the LVL can potentially survive redox freezing over long geological time scales. We also show that the amount of subducted carbon exerts a stronger influence on the stability of carbonate melt than does the mantle redox condition. Concentration dependent melt density leads to rapid melt propagation through channels while a constant melt density causes melt to migrate as a planar front. Our calculations suggest that the LVLs can sequester significant fractions of carbon transported to the mantle by subduction. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165295
Appears in Collections: 气候变化与战略
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作者单位: State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, United Kingdom; University of Chinese Academy of Sciences, Beijing, 100049, China; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States
Recommended Citation:
Sun Y.,Hier-Majumder S.,Xu Y.,et al. Stability and migration of slab-derived carbonate-rich melts above the transition zone[J]. Earth and Planetary Science Letters,2020-01-01,531