气候变化领域集成服务门户(CCPortal): On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins

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DOI	10.1016/j.epsl.2020.116531
	On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins
	Prissel T.C.; Gross J.
发表日期	2020
ISSN	0012821X
卷号	551
英文摘要	We investigate lunar troctolite petrogenesis with a series of forward models. We simulate the cumulate mantle overturn hypothesis by modeling the adiabatic ascent and decompression melting of primary mantle cumulates produced during differentiation of a lunar magma ocean (LMO). Combined equilibrium and fractional crystallization of candidate liquids generated by the melting model can reproduce the predominant constituents of the lunar magnesian-suite (Mg-suite: troctolites and norites), contrary to previous hypotheses. Model results are consistent with previous studies challenging the proposed and long-standing genetic relationship between Mg-suite and gabbronorites. Our Mg-suite petrogenetic model validates a direct temporal and chemical link between Mg-suite melt production and pressure-release melting of primary LMO cumulates. If so, Mg-suite crystallization ages (4345 ± 15 Ma) can be used to constrain the onset and duration of melting associated with mantle overturn. Based on our model results, we propose an alternative mantle overturn hypothesis whereby upwelling olivine-dominated cumulates experience decompression melting to produce the Mg-suite primary melt (∼1.9% melt at ∼2.1 GPa), but that this melt was extracted from depth akin to lunar picritic glass magmas (low-degree partial melts at depths corresponding to ∼1.3–2.5 GPa). Thus, our revised mantle overturn hypothesis reconciles Mg-suite petrogenesis without the expanse of an olivine-dominated upper mantle (as suggested by the current paradigms, but contradicted by orbital data). This hypothesis supports the presence of a low-Ca pyroxene dominated upper mantle, consistent with mantle stratigraphy constrained by experimental and numerical simulations of LMO differentiation and proposed mantle exposures within impact basins. © 2020 Elsevier B.V.
关键词	cumulate mantle overturn impact basins lunar magma ocean lunar troctolite Mg-suite Moon
英文关键词	Magnesia; Melting; Moon; Olivine; Petrology; Stratigraphy; Crystallization age; Decompression melting; Forward models; Fractional crystallization; Gabbronorites; Genetic relationships; Melt production; Pressure release; Orbits; cumulate; magma; mantle convection; melt; melting; Moon; overturn; petrogenesis
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/202841
作者单位	Lunar & Planetary Institute, Universities Space Research Association, 3600 Bay Area Blvd., Houston, TX 77058, United States; Astromaterials Research & Exploration Science Division, NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, United States; Department of Earth & Planetary Sciences Rutgers, the State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, United States; Department of Earth & Planetary Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, United States
推荐引用方式 GB/T 7714	Prissel T.C.,Gross J.. On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins[J],2020,551.
APA	Prissel T.C.,&Gross J..(2020).On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins.Earth and Planetary Science Letters,551.
MLA	Prissel T.C.,et al."On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins".Earth and Planetary Science Letters 551(2020).