气候变化领域集成服务门户(CCPortal): Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin

CCPortal

DOI	10.1073/pnas.0803760105
	Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin
	Head J.W.; Marchant D.R.; Kreslavsky M.A.
发表日期	2008
ISSN	0027-8424
起始页码	13258
结束页码	13263
卷号	105 期号:36
英文摘要	Features seen in portions of a typical midlatitude Martian impact crater show that gully formation follows a geologically recent period of midlatitude glaciation. Geological evidence indicates that, in the relatively recent past, sufficient snow and ice accumulated on the pole-facing crater wall to cause glacial flow and filling of the crater floor with debris-covered glaciers. As glaciation waned, debris-covered glaciers ceased flowing, accumulation zones lost ice, and newly exposed wall alcoves continued as the location for limited snow/frost deposition, entrapment, and preservation. Analysis of the insolation geometry of this pole-facing crater wall, and similar occurrences in other craters at these latitudes on Mars, shows that they are uniquely favored for accumulation of snow and ice, and a relatively more rapid exposure to warmer summer temperatures. We show that, after the last glaciation, melting of residual snow and ice in alcoves could have formed the fluvial channels and sedimentary fans of the gullies. Recent modeling shows that top-down melting can occur in these microenvironments under conditions similar to those currently observed on Mars, if small amounts of snow or frost accumulate in alcoves and channels. Accumulation and melting is even more favored in the somewhat wetter, relatively recent geological past of Mars, after the period of active glaciation. © 2008 by The National Academy of Sciences of the USA.
英文关键词	Craters; Erosion; Fluvial; Glaciation; Snow
语种	英语
scopus关键词	ice; snow; surface water; article; astronomy; climate change; glaciation; melting point; microenvironment; priority journal; sediment; water flow
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159170
作者单位	Head, J.W., Department of Geological Sciences, Brown University, Providence, RI 02912, United States; Marchant, D.R., Department of Earth Sciences, Boston University, Boston, MA 02215, United States; Kreslavsky, M.A., Department of Geological Sciences, Brown University, Providence, RI 02912, United States, Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, United States
推荐引用方式 GB/T 7714	Head J.W.,Marchant D.R.,Kreslavsky M.A.. Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin[J],2008,105(36).
APA	Head J.W.,Marchant D.R.,&Kreslavsky M.A..(2008).Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin.Proceedings of the National Academy of Sciences of the United States of America,105(36).
MLA	Head J.W.,et al."Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin".Proceedings of the National Academy of Sciences of the United States of America 105.36(2008).