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DOI	10.1130/B35185.1
	Deposition of >3.7 ga clay-rich strata of the mawrth vallis group, mars, in lacustrine, alluvial, and aeolian environments
	Lowe D.R.; Bishop J.L.; Loizeau D.; Wray J.J.; Beyer R.A.
发表日期	2020
ISSN	167606
起始页码	17
结束页码	30
卷号	132 期号:2021-01-02
英文摘要	The presence of abundant phyllosilicate minerals in Noachian (>3.7 Ga) rocks on Mars has been taken as evidence that liquid water was stable at or near the surface early in martian history. This study investigates some of these clay-rich strata exposed in crater rim and inverted terrain settings in the Mawrth Vallis region of Mars. In Muara crater the 200-m-thick, clay-rich Mawrth Vallis Group (MVG) is subdivided into five informal units numbered 1 (base) to 5 (top). Unit 1 consists of interbedded sedimentary and volcanic or volcaniclastic units showing weak Fe/Mgsmectite alteration deposited in a range of subaerial depositional settings. Above a major unconformity eroded on Unit 1, the darktoned sediments of Unit 2 and lower Unit 3 are inferred to represent mainly wind-blown sand. These are widely interlayered with and draped by thin layers of light-toned sediment representing fine suspended-load aeolian silt and clay. These sediments show extensive Fe/Mg-smectite alteration, probably reflecting subaerial weathering. Upper Unit 3 and units 4 and 5 are composed of well-layered, finegrained sediment dominated by Al-phyllosilicates, kaolinite, and hydrated silica. Deposition occurred in a large lake or arm of a martian sea. In the inverted terrain 100 km to the NE, Unit 4 shows very young slope failures suggesting that the clay-rich sediments today retain a significant component of water ice. The MVG provides evidence for the presence of large, persistent standing bodies of water on early Mars as well as a complex association of flanking shoreline, alluvial, and aeolian systems. Some of the clays, especially the Fe/Mg smectites in upper units 1 and 2 appear to have formed through subaerial weathering whereas the aluminosilicates, kaolinite, and hydrated silica of units 3, 4, and 5 formed mainly through alteration of fine sediment in subaqueous environments. © 2019 The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184884
作者单位	Department of Geological Sciences, Stanford University, StanfordCA 94305-2115, United States; SETI and NASA-Ames Research Center, Mountain View, CA, United States; Université Claude Bernard Lyon 1, Ens de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, F-69622, France; Institut d'Astrophysique Spatiale, Université Paris Sud, Orsay, F-91405, France; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0340, United States
推荐引用方式 GB/T 7714	Lowe D.R.,Bishop J.L.,Loizeau D.,et al. Deposition of >3.7 ga clay-rich strata of the mawrth vallis group, mars, in lacustrine, alluvial, and aeolian environments[J],2020,132(2021-01-02).
APA	Lowe D.R.,Bishop J.L.,Loizeau D.,Wray J.J.,&Beyer R.A..(2020).Deposition of >3.7 ga clay-rich strata of the mawrth vallis group, mars, in lacustrine, alluvial, and aeolian environments.Bulletin of the Geological Society of America,132(2021-01-02).
MLA	Lowe D.R.,et al."Deposition of >3.7 ga clay-rich strata of the mawrth vallis group, mars, in lacustrine, alluvial, and aeolian environments".Bulletin of the Geological Society of America 132.2021-01-02(2020).