DOI: 10.1073/pnas.0803760105
论文题名: Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin
作者: Head J.W. ; Marchant D.R. ; Kreslavsky M.A.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2008
卷: 105, 期: 36 起始页码: 13258
结束页码: 13263
语种: 英语
英文关键词: Craters
; Erosion
; Fluvial
; Glaciation
; Snow
Scopus关键词: ice
; snow
; surface water
; article
; astronomy
; climate change
; glaciation
; melting point
; microenvironment
; priority journal
; sediment
; water flow
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/162459
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
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]. Proceedings of the National Academy of Sciences of the United States of America,2008-01-01,105(36)