DOI: 10.1038/ngeo3030
论文题名: Earth's early O2 cycle suppressed by primitive continents
作者: Smit M.A. ; Mezger K.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2017
卷: 10, 期: 10 起始页码: 788
结束页码: 792
语种: 英语
Scopus关键词: andesite
; atmospheric chemistry
; continental crust
; hydrogen sulfide
; marine environment
; olivine
; oxygen
; oxygenation
; terrigenous deposit
英文摘要: Free oxygen began to accumulate in Earth's surface environments between 3.0 and 2.4 billion years ago. Links between oxygenation and changes in the composition of continental crust during this time are suspected, but have been difficult to demonstrate. Here we constrain the average composition of the exposed continental crust since 3.7 billion years ago by compiling records of the Cr/U ratio of terrigenous sediments. The resulting record is consistent with a predominantly mafic crust prior to 3.0 billion years ago, followed by a 500- to 700-million-year transition to a crust of modern andesitic composition. Olivine and other Mg-rich minerals in the mafic Archaean crust formed serpentine minerals upon hydration, continuously releasing O2-scavenging agents such as dihydrogen, hydrogen sulfide and methane to the environment. Temporally, the decline in mafic crust capable of such process coincides with the first accumulation of O2 in the oceans, and subsequently the atmosphere. We therefore suggest that Earth's early O2 cycle was ultimately limited by the composition of the exposed upper crust, and remained underdeveloped until modern andesitic continents emerged. © 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/105696
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 Earth, Ocean and Atmospheric Sciences, University of British Columbia, Main Mall, Vancouver, Canada; Institut für Geologie, Universität Bern, Baltzerstrasse 1+3, Bern, Switzerland
Recommended Citation:
Smit M.A.,Mezger K.. Earth's early O2 cycle suppressed by primitive continents[J]. Nature Geoscience,2017-01-01,10(10)