DOI: 10.1016/j.epsl.2018.04.058
Scopus记录号: 2-s2.0-85046781342
论文题名: Nature of late accretion to Earth inferred from mass-dependent Ru isotopic compositions of chondrites and mantle peridotites
作者: Hopp T. ; Kleine T.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 494 起始页码: 50
结束页码: 59
语种: 英语
英文关键词: chondrites
; Earth's mantle
; late accretion
; mass-dependent isotope fractionation
; ruthenium
; sulfide segregation
Scopus关键词: Coremaking
; Isotopes
; Meteorites
; Mixtures
; Ruthenium
; Segregation (metallography)
; Sulfur compounds
; chondrites
; Earth's mantle
; Late accretions
; Mass dependent isotope fractionation
; Sulfide segregations
; Ruthenium compounds
; accretion
; carbonaceous chondrite
; enstatite chondrite
; igneous geochemistry
; isotopic composition
; isotopic fractionation
; mantle source
; ordinary chondrite
; peridotite
; ruthenium
; sulfide
英文摘要: Elevated abundances of highly siderophile elements in Earth's mantle are thought to reflect the late accretion of primitive material after the cessation of core formation, but the origin of this material, and whether or not it can be linked to specific types of meteorites remain debated. Here, mass-dependent Ru isotopic data for chondrites and terrestrial peridotites are reported to evaluate the chemical nature and type of the late-accreted material. After correction for nucleosynthetic Ru isotope anomalies, enstatite, ordinary and carbonaceous chondrites all have indistinguishable mass-dependent Ru isotopic compositions. Thus, neither distinct formation conditions in the solar nebula nor parent body processes resulted in significant mass-dependent Ru isotope fractionation. All five terrestrial peridotites analyzed have mass-dependent Ru isotopic compositions that are indistinguishable from each other and from the composition of chondrites. The chondritic mass-dependent Ru isotopic composition of Earth's mantle is difficult to reconcile with prior suggestions that the late accretionary assemblage was a mixture of chondrites with a chemically evolved metal component. Although this mixture can reproduce the suprachondritic Ru/Ir inferred for Earth's mantle, it consistently predicts a heavy Ru isotopic composition of Earth's mantle with respect to chondrites. This is because metal components with elevated Ru/Ir are also enriched in heavy Ru isotopes, resulting from isotope fractionation during core crystallization. Thus, if late accretion involved impacts of differentiated protoplanetary bodies, then the projectile cores must have been either homogenized upon impact, or added to Earth's mantle completely, because otherwise Earth's mantle would have inherited a non-chondritic mass-dependent Ru isotopic composition from the unrepresentative sampling of core material. © 2018 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109848
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Institut für Planetologie, University of Münster, Wilhelm-Klemm-Str. 10, Münster, 48149, Germany
Recommended Citation:
Hopp T.,Kleine T.. Nature of late accretion to Earth inferred from mass-dependent Ru isotopic compositions of chondrites and mantle peridotites[J]. Earth and Planetary Science Letters,2018-01-01,494