DOI: 10.1038/NGEO3054
论文题名: Early Earth mantle heterogeneity revealed by light oxygen isotopes of Archaean komatiites
作者: Byerly B.L. ; Kareem K. ; Bao H. ; Byerly G.R.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2017
卷: 10, 期: 11 起始页码: 871
结束页码: 875
语种: 英语
Scopus关键词: Archean
; early Earth
; Hadean
; heterogeneity
; isotopic composition
; magmatism
; mantle
; mantle source
; olivine
; oxygen isotope
; volcanic rock
; Barberton Greenstone Belt
; Kaapvaal Craton
英文摘要: Geodynamic processes on early Earth, especially the interaction between the crust and deep mantle, are poorly constrained and subject to much debate. The rarity of fresh igneous materials more than 3 billion years old accounts for much of this uncertainty. Here we examine 3.27-billion-year-old komatiite lavas from Weltevreden Formation in the Barberton greenstone belt, which is part of the Kaapvaal Craton in Southern Africa. We show that primary magmatic compositions of olivine are well preserved in these lavas based on major and trace element systematics. These komatiitic lavas represent products of deep mantle plumes. Oxygen isotope compositions (d18O) of the fresh olivine measured by laser fluorination are consistently lighter (about 2h) than those obtained from modern mantle-derived volcanic rocks. These results suggest a mantle source for the Weltevreden komatiites that is unlike the modern mantle and one that reflects mantle heterogeneity left over from a Hadean magma ocean. The anomalously light d18O may have resulted from fractionation of deep magma ocean phases, as has been proposed to explain lithophile and siderophile isotope compositions of Archaean komatiites. © 2017 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/105675
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 and Geophysics, Louisiana State University, Baton Rouge, LA, United States; School of Earth and Space Sciences, Peking University, Beijing, China
Recommended Citation:
Byerly B.L.,Kareem K.,Bao H.,et al. Early Earth mantle heterogeneity revealed by light oxygen isotopes of Archaean komatiites[J]. Nature Geoscience,2017-01-01,10(11)