DOI: 10.1016/j.epsl.2018.08.009
Scopus记录号: 2-s2.0-85051472072
论文题名: The influence of deep mantle compositional heterogeneity on Earth's thermal evolution
作者: Li M. ; McNamara A.K.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 500 起始页码: 86
结束页码: 96
语种: 英语
英文关键词: compositional heterogeneity
; lowermost mantle
; thermal evolution
; thermochemical piles
Scopus关键词: Heat flux
; Shear flow
; Compositional heterogeneity
; Critical questions
; Early differentiation
; Lowermost mantle
; Morphologic changes
; Shear velocities
; Thermal evolution
; Time evolutions
; Piles
; geodynamics
; geomorphology
; heat flux
; heterogeneity
; lower mantle
; mantle structure
; thermal evolution
; thermochemistry
英文摘要: The seismically-observed large low shear velocity provinces in the Earth's lowermost mantle have been hypothesized to be caused by thermochemical piles of compositionally distinct, more-primitive material which may be remnants of Earth's early differentiation. However, one critical question is how the Earth's thermal evolution is affected by the long-term presence of the large-scale compositional heterogeneity in the lowermost mantle. Here, we perform geodynamical calculations to investigate the time evolution of the morphology of large-scale compositional heterogeneity and its influence on the Earth's long-term thermal evolution. Our results show that a global layer of intrinsically dense material in the lowermost mantle significantly suppresses the CMB heat flux, which leads to faster cooling of the background mantle relative to an isochemical mantle. As the background mantle cools, the intrinsically dense material is gradually pushed into isolated thermochemical piles by cold downwellings. The size of the piles also decreases with time due to entraining of pile material into the background mantle. The morphologic change of the accumulations of intrinsic dense material eventually causes a gradual increase of CMB heat flux, which significantly reduces the cooling rate of Earth's mantle. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109692
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Arizona State University, School of Earth and Space Exploration, PO Box 876004, Tempe, AZ 85287-6004, United States; Michigan State University, Department of Earth and Environmental Sciences, Natural Science Building, East Lansing, MI 48824, United States
Recommended Citation:
Li M.,McNamara A.K.. The influence of deep mantle compositional heterogeneity on Earth's thermal evolution[J]. Earth and Planetary Science Letters,2018-01-01,500