DOI: 10.1038/ngeo2137
论文题名: Low palaeopressure of the martian atmosphere estimated from the size distribution of ancient craters
作者: Kite E.S. ; Williams J.-P. ; Lucas A. ; Aharonson O.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 5 起始页码: 335
结束页码: 339
语种: 英语
Scopus关键词: atmospheric pressure
; crater
; estimation method
; fluvial landform
; Martian atmosphere
; size distribution
英文摘要: The decay of the martian atmosphere - which is dominated by carbon dioxide - is a component of the long-term environmental change on Mars from a climate that once allowed rivers to flow to the cold and dry conditions of today. The minimum size of craters serves as a proxy for palaeopressure of planetary atmospheres, because thinner atmospheres permit smaller objects to reach the surface at high velocities and form craters. The Aeolis Dorsa region near Gale crater on Mars contains a high density of preserved ancient craters interbedded with river deposits and thus can provide constraints on atmospheric density at the time of fluvial activity. Here we use high-resolution images and digital terrain models from the Mars Reconnaissance Orbiter to identify ancient craters in deposits in Aeolis Dorsa that date to about 3.6 Gyr ago and compare their size distribution with models of atmospheric filtering of impactors. We obtain an upper limit of 0.9 ± 0.1 bar for the martian atmospheric palaeopressure, rising to 1.9 ± 0.2 bar if rimmed circular mesas - interpreted to be erosionally-resistant fills or floors of impact craters - are excluded. We assume target properties appropriate for desert alluvium: if sediment had rock-mass strength similar to bedrock at the time of impact, the paleopressure upper limit increases by a factor of up to two. If Mars did not have a stable multibar atmosphere at the time that the rivers were flowing - as suggested by our results - then a warm and wet CO2/H2O greenhouse is ruled out, and long-term average temperatures were most likely below freezing. © 2014 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106527
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Geological and Planetary Sciences, Caltech, CA 91125, United States; Earth and Space Sciences, University of California, Los Angeles, CA 90025, United States; Helen Kimmel Center for Planetary Science, Weizmann Institute of Science, Rehovot 76100, Israel; Princeton University, Princeton, NJ 08544, United States
Recommended Citation:
Kite E.S.,Williams J.-P.,Lucas A.,et al. Low palaeopressure of the martian atmosphere estimated from the size distribution of ancient craters[J]. Nature Geoscience,2014-01-01,7(5)