气候变化领域集成服务门户(CCPortal): Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability

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DOI	10.1038/s41561-019-0380-0
	Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability
	Moser D.E.; Arcuri G.A.; Reinhard D.A.; White L.F.; Darling J.R.; Barker I.R.; Larson D.J.; Irving A.J.; McCubbin F.M.; Tait K.T.; Roszjar J.; Wittmann A.; Davis C.
发表日期	2019
ISSN	17520894
卷号	12 期号:7
英文摘要	The timing of the wane in heavy meteorite bombardment of the inner planets is debated. Its timing determines the onset of crustal conditions consistently below the thermal and shock pressure limits for microbiota survival, and so bounds the occurrence of conditions that allow planets to be habitable. Here we determine this timing for Mars by examining the metamorphic histories of the oldest known Martian minerals, 4.476–4.429-Gyr-old zircon and baddeleyite grains in meteorites derived from the southern highlands. We use electron microscopy and atom probe tomography to show that none of these grains were exposed to the life-limiting shock pressure of 78 GPa. 97% of the grains exhibit weak-to-no shock metamorphic features and no thermal overprints from shock-induced melting. By contrast, about 80% of the studied grains from bombarded crust on Earth and the Moon show such features. The giant impact proposed to have created Mars’ hemispheric dichotomy must, therefore, have taken place more than 4.48 Gyr ago, with no later cataclysmic bombardments. Considering thermal habitability models, we conclude that portions of Mars’ crust reached habitable pressures and temperatures by 4.2 Gyr ago, the onset of the Martian ‘wet’ period, about 0.5 Gyr earlier than the earliest known record of life on Earth. Early abiogenesis by 4.2 Gyr ago, is now tenable for both planets. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.
语种	英语
scopus关键词	Earth; Mars; meteorite; Moon; probe; survival
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/124642
作者单位	Department of Earth Sciences, University of Western Ontario, London, ON, Canada; CAMECA Instruments Inc., Madison, WI, United States; Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada; School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, United Kingdom; Department of Earth and Space Sciences, University of Washington, Seattle, WA, United States; NASA Johnson Space Center, Houston, TX, United States; Department of Mineralogy and Petrography, Natural History Museum Vienna, Vienna, Austria; Eyring Materials Center, Arizona State University, Tempe, AZ, United States
推荐引用方式 GB/T 7714	Moser D.E.,Arcuri G.A.,Reinhard D.A.,et al. Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability[J],2019,12(7).
APA	Moser D.E..,Arcuri G.A..,Reinhard D.A..,White L.F..,Darling J.R..,...&Davis C..(2019).Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability.Nature Geoscience,12(7).
MLA	Moser D.E.,et al."Decline of giant impacts on Mars by 4.48 billion years ago and an early opportunity for habitability".Nature Geoscience 12.7(2019).