气候变化领域集成服务门户(CCPortal): A coupled model of episodic warming, oxidation and geochemical transitions on early Mars

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DOI	10.1038/s41561-021-00701-8
	A coupled model of episodic warming, oxidation and geochemical transitions on early Mars
	Wordsworth R.; Knoll A.H.; Hurowitz J.; Baum M.; Ehlmann B.L.; Head J.W.; Steakley K.
发表日期	2021
ISSN	17520894
起始页码	127
结束页码	132
卷号	14 期号:3
英文摘要	Reconciling the geology of Mars with models of atmospheric evolution remains a major challenge. Martian geology is characterized by past evidence for episodic surface liquid water, and geochemistry indicating a slow and intermittent transition from wetter to drier and more oxidizing surface conditions. Here we present a model that incorporates randomized injection of reducing greenhouse gases and oxidation due to hydrogen escape to investigate the conditions responsible for these diverse observations. We find that Mars could have transitioned repeatedly from reducing (hydrogen-rich) to oxidizing (oxygen-rich) atmospheric conditions in its early history. Our model predicts a generally cold early Mars, with mean annual temperatures below 240 K. If peak reducing-gas release rates and background carbon dioxide levels are high enough, it nonetheless exhibits episodic warm intervals sufficient to degrade crater walls, form valley networks and create other fluvial/lacustrine features. Our model also predicts transient build-up of atmospheric oxygen, which can help explain the occurrence of oxidized mineral species such as manganese oxides at Gale Crater. We suggest that the apparent Noachian–Hesperian transition from phyllosilicate deposition to sulfate deposition around 3.5 billion years ago can be explained as a combined outcome of increasing planetary oxidation, decreasing groundwater availability and a waning bolide impactor flux, which dramatically slowed the remobilization and thermochemical destruction of surface sulfates. Ultimately, rapid and repeated variations in Mars’s early climate and surface chemistry would have presented both challenges and opportunities for any emergent microbial life. © 2021, The Author(s), under exclusive licence to Springer Nature Limited.
英文关键词	bolide; carbon dioxide; hydrogen; Mars; oxidation; phyllosilicate; remobilization; sulfate
语种	英语
来源期刊	Nature Geoscience
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/206976
作者单位	School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States; Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States; Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States; Department of Geosciences, Stony Brook University, Stony Brook, NY, United States; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; NASA Jet Propulsion Laboratory, Pasadena, CA, United States; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States; NASA Ames Research Center, Mountain View, CA, United States
推荐引用方式 GB/T 7714	Wordsworth R.,Knoll A.H.,Hurowitz J.,et al. A coupled model of episodic warming, oxidation and geochemical transitions on early Mars[J],2021,14(3).
APA	Wordsworth R..,Knoll A.H..,Hurowitz J..,Baum M..,Ehlmann B.L..,...&Steakley K..(2021).A coupled model of episodic warming, oxidation and geochemical transitions on early Mars.Nature Geoscience,14(3).
MLA	Wordsworth R.,et al."A coupled model of episodic warming, oxidation and geochemical transitions on early Mars".Nature Geoscience 14.3(2021).