气候变化领域集成服务门户(CCPortal): Chemical evolution of the continental crust from a data-driven inversion of terrigenous sediment compositions

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DOI	10.1016/j.epsl.2020.116090
	Chemical evolution of the continental crust from a data-driven inversion of terrigenous sediment compositions
	Ptáček M.P.; Dauphas N.; Greber N.D.
发表日期	2020
ISSN	0012821X
卷号	539
英文摘要	The nature of emerged continents through time is highly debated. Several studies relying on trace element data concluded that the Archaean crust was predominantly mafic, while Ti isotope systematics point to an Archaean crust that was predominantly felsic. Here, we resolve the inconsistency between these two approaches by applying a novel statistical method to a compilation of published elemental concentrations in terrigenous sediments (the OrTeS database). We use a filter based on the Local Outlier Factor to reject sediment samples that have been affected by alteration processes or mineral fractionation during transport. The nature of the emerged continents is calculated using an inverse mixing model based on a Markov Chain Monte Carlo algorithm. A procedure is presented to automatically select elemental ratios that are best suited for constraining the sediment provenance. We find that for all systems that accurately reconstruct the modern-day composition of the continents, a continuous >50% felsic contribution is required to explain the composition of fine-grained terrigenous sediments starting from 3.5 billion years ago. This finding is consistent with an early onset of plate tectonics. We estimate the geothermal gradient in the Archaean upper continental crust by tracking the reconstructed concentrations of the radiogenic heat-producing elements K, U, and Th through time. Radioactive heat production in the bulk continental crust was 50% higher in the Archaean compared to the present, resulting in a continental geothermal gradient that was about 40% higher. © 2020
关键词	Archaean geochemistry continental composition crustal geotherm plate tectonics
英文关键词	Geothermal energy; Markov chains; Trace elements; Continental crusts; Elemental concentrations; Geothermal gradients; Local Outlier Factor; Markov chain monte carlo algorithms; Sediment provenance; Terrigenous sediment; Upper continental crust; Sediments; algorithm; Archean; chemical composition; concentration (composition); continental crust; data inversion; geothermal gradient; terrigenous deposit
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202843
作者单位	Origins Laboratory, Department of the Geophysical Sciences, Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637, United States; Institut für Geologie, Universität Bern, Bern, 3012, Switzerland
推荐引用方式 GB/T 7714	Ptáček M.P.,Dauphas N.,Greber N.D.. Chemical evolution of the continental crust from a data-driven inversion of terrigenous sediment compositions[J],2020,539.
APA	Ptáček M.P.,Dauphas N.,&Greber N.D..(2020).Chemical evolution of the continental crust from a data-driven inversion of terrigenous sediment compositions.Earth and Planetary Science Letters,539.
MLA	Ptáček M.P.,et al."Chemical evolution of the continental crust from a data-driven inversion of terrigenous sediment compositions".Earth and Planetary Science Letters 539(2020).