DOI: 10.1038/ngeo2772
论文题名: Redox-induced lower mantle density contrast and effect on mantle structure and primitive oxygen
作者: Gu T. ; Li M. ; McCammon C. ; Lee K.K.M.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 9 起始页码: 723
结束页码: 727
语种: 英语
Scopus关键词: geodynamics
; high pressure
; lower mantle
; mantle convection
; mantle structure
; mineral alteration
; oxygen
; redox conditions
; shear strength
; temperature profile
; upper mantle
英文摘要: The mantle comprises nearly three-quarters of Earth's volume and through convection connects the deep interior with the lithosphere and atmosphere. The composition of the mantle determines volcanic emissions, which are intimately linked to evolution of the primitive atmosphere. Fundamental questions remain on how and when the proto-Earth mantle became oxidized, and whether redox state is homogeneous or developed large-scale structures. Here we present experiments in which we subjected two synthetic samples of nearly identical composition that are representative of the lower mantle (enstatite chondrite), but synthesized under different oxygen fugacities, to pressures and temperatures up to 90 GPa and 2,400 K. In addition to the mineral bridgmanite, compression of the more reduced material also produced Al 2 O 3 as a separate phase, and the resulting assemblage is about 1 to 1.5% denser than in experiments with the more oxidized material. Our geodynamic simulations suggest that such a density difference can cause a rapid ascent and accumulation of oxidized material in the upper mantle, with descent of the denser reduced material to the core-mantle boundary. We suggest that the resulting heterogeneous redox conditions in Earth's interior can contribute to the large low-shear velocity provinces in the lower mantle and the evolution of atmospheric oxygen. © 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105935
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: Department of Geology AndGeophysics, Yale University, New Haven, CT, United States; School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States; Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany
Recommended Citation:
Gu T.,Li M.,McCammon C.,et al. Redox-induced lower mantle density contrast and effect on mantle structure and primitive oxygen[J]. Nature Geoscience,2016-01-01,9(9)