DOI: 10.1038/NGEO3048
论文题名: Silicate Earth's missing niobium may have been sequestered into asteroidal cores
作者: Munker C. ; Fonseca R.O.C. ; Schulz T.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2017
卷: 10, 期: 11 起始页码: 822
结束页码: 826
语种: 英语
Scopus关键词: asteroid
; chondrite
; Earth
; geochemistry
; mantle
; meteorite
; niobium
; tantalum
英文摘要: Geochemical models describing the behaviour of niobium during Earth's growth rely on the general paradigm that niobium was delivered by Earth's asteroidal building blocks at chondritic abundances. This paradigm is based on the observation that niobium is traditionally regarded as a refractory and strongly lithophile element, and thus stored in the silicate portions of Earth and differentiated asteroids. However, Earth's silicate mantle is instead selectively depleted in niobium, in marked contrast to the silicate mantles of many asteroids and smaller planets that apparently lack any significant depletion in niobium. Here we present results of high-precision measurements for niobium and other lithophile elements in representative meteorites from various small differentiated asteroids. Our data, along with the results of low-pressure experiments, show that in more reduced asteroids-such as Earth's first building blocks-niobium is moderately chalcophile and more so than its geochemical twin tantalum by an order of magnitude. Accordingly, niobium can be sequestered into the cores of more reduced asteroids during differentiation via the segregation of sulfide melts in a carbon-saturated environment. We suggest that the niobium deficit in Earth's silicate mantle may be explained by the Earth's silicate mantle preferentially accreting the silicate portions of reduced asteroidal building blocks. © 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/105686
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: Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicher Strasse 49b, Köln, Germany; Steinmann Institut, Universität Bonn, Poppelsdorfer Schloss, Bonn, Germany; Department für Lithosphärenforschung, Universität Wien, Althanstrasse 14, Wien, Austria
Recommended Citation:
Munker C.,Fonseca R.O.C.,Schulz T.. Silicate Earth's missing niobium may have been sequestered into asteroidal cores[J]. Nature Geoscience,2017-01-01,10(11)