气候变化领域集成服务门户(CCPortal): Bulk composition of regolith fines on lunar crater floors: Initial investigation by LRO/Mini-RF

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DOI	10.1016/j.epsl.2020.116274
	Bulk composition of regolith fines on lunar crater floors: Initial investigation by LRO/Mini-RF
	Heggy E.; Palmer E.M.; Thompson T.W.; Thomson B.J.; Patterson G.W.
发表日期	2020
ISSN	0012821X
卷号	541
英文摘要	Identifying polarimetric radar signatures of ice in smooth regolith fines on the floors of permanently shadowed lunar craters is hindered by uncertainties in their dielectric properties. We address this deficiency through polarimetric radar analysis of surface backscatter to derive the dielectric constant (εr ′) of smooth, rock-free regolith fines covering brecciated crater floors observed by Mini-RF, which offer ideal locations for unambiguous retrieval of surface εr ′ from linear polarimetric scattering models and CPR analysis for volatile identification. Specifically, we select fines covering crater fills in north polar and equatorial regions to constrain the range of variability of εr ′ as a function of latitude and crater diameter, where we hypothesize that the latter is indicative of the excavation depth of these fines. Our observations suggest that there is measurable variability in the dielectric properties of fines on lunar crater floors as a function of crater size and potentially with impact excavation depth, suggesting that small craters <5-km in diameter have εr ′ ranging from 2.3-to-3, and large ones >5-km have higher values of εr ′ that range from 3-to-3.8. We find that the most plausible explanation for the observed variability of εr ′ of regolith fines on crater floors is mineralogical differences, suggesting an increase in metal abundance in the original excavated substrate with depth, i.e., in the uppermost kilometer of the lunar crust. Finally, we suggest that regolith fines on the floors of permanently shadowed craters <5 km in diameter are optimal targets for the unambiguous detection of water-ice enrichment using S-band radar observations. © 2020 Elsevier B.V.
关键词	dielectric properties ice Moon regolith
英文关键词	Dielectric properties; Excavation; Moon; Polarimeters; Radar; Bulk compositions; Crater diameter; Equatorial regions; Lunar crusts; Metal abundances; Optimal target; Polarimetric radars; Polarimetric scattering; Floors; backscatter; breccia; crater; dielectric property; lunar crust; mineralogy; Moon; radar; regolith
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/202639
作者单位	University of Southern California, Ming Hsieh Department of Electrical and Computer Engineering, 3737 Watt Way, Los Angeles, CA 90089, United States; Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States; Department of Earth and Planetary Sciences, The University of Tennessee Knoxville, 1621 Cumberland Avenue, Knoxville, TN 37996, United States; The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
推荐引用方式 GB/T 7714	Heggy E.,Palmer E.M.,Thompson T.W.,et al. Bulk composition of regolith fines on lunar crater floors: Initial investigation by LRO/Mini-RF[J],2020,541.
APA	Heggy E.,Palmer E.M.,Thompson T.W.,Thomson B.J.,&Patterson G.W..(2020).Bulk composition of regolith fines on lunar crater floors: Initial investigation by LRO/Mini-RF.Earth and Planetary Science Letters,541.
MLA	Heggy E.,et al."Bulk composition of regolith fines on lunar crater floors: Initial investigation by LRO/Mini-RF".Earth and Planetary Science Letters 541(2020).