DOI: 10.1016/j.epsl.2019.116007
论文题名: Markov chain Monte Carlo inversion of mantle temperature and source composition, with application to Reykjanes Peninsula, Iceland
作者: Brown E.L. ; Petersen K.D. ; Lesher C.E.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 532 语种: 英语
中文关键词: Iceland
; inversion
; mantle melting
; MCMC
; potential temperature
; pyroxenite
英文关键词: Basalt
; Inverse problems
; Markov processes
; Metal melting
; Minerals
; Trace elements
; Icelands
; inversion
; Mantle melting
; MCMC
; Potential temperature
; pyroxenite
; Monte Carlo methods
; chemical composition
; data interpretation
; igneous geochemistry
; mantle source
; mantle structure
; Markov chain
; Monte Carlo analysis
; petrogenesis
; pyroxenite
; temperature profile
; Iceland
; Reykjanes Peninsula
英文摘要: The compositions and volumes of basalt generated by partial melting of the Earth's mantle provide fundamental constraints on the thermo-chemical conditions of the upper mantle. However, using melting products to interpret uniquely these conditions is challenging given the complexity of the melting and melt aggregation processes. Forward models simulating melting of lithologically heterogeneous mantle sources can account for this complexity, but require assumptions about key model input parameters, and the quality of the model fits to the observations are rarely, if at all, considered. Alternatively, inverse melting models can provide estimates of the quality of model fits to the observations, but as of yet, do not account for the presence of lithologic heterogeneity in the mantle source. To overcome these limitations, we present an inverse method coupling a Markov chain Monte Carlo (MCMC) sampling method with the REEBOX PRO forward mantle melting model. We use this tool to constrain mantle potential temperature, melt volumes, and the trace element and isotopic compositions of mantle source lithologies beneath the Reykjanes Peninsula of Iceland. We consider a range of plausible pyroxenite compositions (KG1, G2, and MIX1G) that span much of the range of natural pyroxenite compositions, and constrain the mantle potential temperature between 1455 and 1480 °C and pyroxenite abundance between 6.5 and 8.5%. These results are independent of the choice of pyroxenite composition and indicate that elevated potential temperatures and modest pyroxenite abundances are robust features of the Reykjanes Peninsula mantle source. The permitted ranges of pyroxenite trace element compositions vary as a function of pyroxenite fertility and mineralogy, but differ from the compositions of subduction-modified recycled oceanic crust typically used in previous models, indicating a more complex petrogenetic origin for the pyroxenite source than previously considered. As all of the pyroxenites employed here yield equally good fits to the geochemical and geophysical observations along the Reykjanes Peninsula, forward models should not be used to constrain the major element character of pyroxenite present in mantle source regions based solely on the trace element/isotopic compositions (and volumes) of basalts. Given the range of lithologies included in REEBOX PRO and the flexibility of MCMC inversion, this method may be applied to constrain thermal and compositional source characteristics in a wide variety of basalt source regions. © 2019 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164890
Appears in Collections: 气候变化与战略
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作者单位: Dept. of Geoscience, Aarhus University, Denmark; Aarhus GeoSoftware, Denmark; Dept. of Earth and Planetary Sciences, University of California, Davis, United States
Recommended Citation:
Brown E.L.,Petersen K.D.,Lesher C.E.. Markov chain Monte Carlo inversion of mantle temperature and source composition, with application to Reykjanes Peninsula, Iceland[J]. Earth and Planetary Science Letters,2020-01-01,532