DOI: 10.1016/j.epsl.2017.12.039
Scopus记录号: 2-s2.0-85044340241
论文题名: Pb evolution in the Martian mantle
作者: Bellucci J.J. ; Nemchin A.A. ; Whitehouse M.J. ; Snape J.F. ; Bland P. ; Benedix G.K. ; Roszjar J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 485 起始页码: 79
结束页码: 87
语种: 英语
英文关键词: geochemical modeling
; late accretion
; Mars
; Martian mantle
; Pb isotopes
; SNCs
Scopus关键词: Earth (planet)
; Isotopes
; Mass spectrometry
; Meteorites
; Secondary ion mass spectrometry
; Silicates
; Geochemical modeling
; Late accretions
; Mars
; Martian mantle
; Pb isotopes
; SNCs
; Lead
; accretion
; crystallization
; geochemistry
; isotopic composition
; lead
; mantle structure
; Mars
; meteorite
; modeling
英文摘要: The initial Pb compositions of one enriched shergottite, one intermediate shergottite, two depleted shergottites, and Nakhla have been measured by Secondary Ion Mass Spectrometry (SIMS). These values, in addition to data from previous studies using an identical analytical method performed on three enriched shergottites, ALH 84001, and Chassigny, are used to construct a unified and internally consistent model for the differentiation history of the Martian mantle and crystallization ages for Martian meteorites. The differentiation history of the shergottites and Nakhla/Chassigny are fundamentally different, which is in agreement with short-lived radiogenic isotope systematics. The initial Pb compositions of Nakhla/Chassigny are best explained by the late addition of a Pb-enriched component with a primitive, non-radiogenic composition. In contrast, the Pb isotopic compositions of the shergottite group indicate a relatively simple evolutionary history of the Martian mantle that can be modeled based on recent results from the Sm–Nd system. The shergottites have been linked to a single mantle differentiation event at 4504 Ma. Thus, the shergottite Pb isotopic model here reflects a two-stage history 1) pre-silicate differentiation (4504 Ma) and 2) post-silicate differentiation to the age of eruption (as determined by concordant radiogenic isochron ages). The μ-values (238U/204Pb) obtained for these two different stages of Pb growth are μ1 of 1.8 and a range of μ2 from 1.4–4.7, respectively. The μ1-value of 1.8 is in broad agreement with enstatite and ordinary chondrites and that proposed for proto Earth, suggesting this is the initial μ-value for inner Solar System bodies. When plotted against other source radiogenic isotopic variables (Sri, γ187Os, ε143Nd, and ε176Hf), the second stage mantle evolution range in observed mantle μ-values display excellent linear correlations (r2>0.85) and represent a spectrum of Martian mantle mixing-end members (depleted, intermediate, enriched). © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110046
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: Department of Geosciences, Swedish Museum of Natural History, Stockholm, SE-104 05, Sweden; Department of Applied Geology, Curtin University, Perth, WA 6845, Australia; Department of Mineralogy and Petrography, Natural History Museum Vienna, Burgring 7, Vienna, 1010, Austria
Recommended Citation:
Bellucci J.J.,Nemchin A.A.,Whitehouse M.J.,et al. Pb evolution in the Martian mantle[J]. Earth and Planetary Science Letters,2018-01-01,485