DOI: 10.1038/ngeo2271
论文题名: Nitrogen speciation in upper mantle fluids and the origin of Earth's nitrogen-rich atmosphere
作者: Mikhail S. ; Sverjensky D.A.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 11 起始页码: 816
结束页码: 819
语种: 英语
Scopus关键词: atmospheric chemistry
; degassing
; Earth
; mantle chemistry
; nitrogen
; oxidation
; speciation (chemistry)
; subduction
; thermodynamics
; upper mantle
英文摘要: Volatile elements stored in the mantles of terrestrial planets escape through volcanic degassing, and thereby influence planetary atmospheric evolution and habitability. Compared with the atmospheres of Venus and Mars, Earth's atmosphere is nitrogen-rich relative to primordial noble gas concentrations1-3. The compatibility of volatile elements in mantle minerals versus melts and fluids controls how readily these elements are degassed. However, the speciation of nitrogen in mantle fluids is not well constrained4-6. Here we present thermodynamic calculations that establish the speciation of nitrogen in aqueous fluids under upper mantle conditions.We find that, under the relatively oxidized conditions of Earth's mantle wedges at convergent plate margins7-9, nitrogen is expected to exist predominantly as N2 in fluids and, therefore, be degassed easily. In contrast, undermore reducing conditions elsewhere in the Earth's upper mantle and in the mantles of Venus and Mars, nitrogen is expected predominantly in the form of ammonium (NH4+) in aqueous fluids. Ammonium is moderately compatible in upper mantle minerals10,11 and unconducive to nitrogen degassing. We conclude that Earth's oxidized mantle wedge conditions - a result of subduction and hence plate tectonics - favour the development of a nitrogen-enriched atmosphere, relative to the primordial noble gases, whereas the atmospheres of Venus and Mars have less nitrogen because they lack plate tectonics. © 2014 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106614
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: Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, United States; Johns Hopkins University, Department of Earth and Planetary Sciences, Baltimore, Maryland, United States
Recommended Citation:
Mikhail S.,Sverjensky D.A.. Nitrogen speciation in upper mantle fluids and the origin of Earth's nitrogen-rich atmosphere[J]. Nature Geoscience,2014-01-01,7(11)