Publication Date:
2011-02-05
Description:
Despite radically different environmental conditions, terrestrial and martian dunes bear a strong resemblance, indicating that the basic processes of saltation and grainfall (sand avalanching down the dune slipface) operate on both worlds. Here, we show that martian dunes are subject to an additional modification process not found on Earth: springtime sublimation of Mars' CO(2) seasonal polar caps. Numerous dunes in Mars' north polar region have experienced morphological changes within a Mars year, detected in images acquired by the High-Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter. Dunes show new alcoves, gullies, and dune apron extension. This is followed by remobilization of the fresh deposits by the wind, forming ripples and erasing gullies. The widespread nature of these rapid changes, and the pristine appearance of most dunes in the area, implicates active sand transport in the vast polar erg in Mars' current climate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hansen, C J -- Bourke, M -- Bridges, N T -- Byrne, S -- Colon, C -- Diniega, S -- Dundas, C -- Herkenhoff, K -- McEwen, A -- Mellon, M -- Portyankina, G -- Thomas, N -- New York, N.Y. -- Science. 2011 Feb 4;331(6017):575-8. doi: 10.1126/science.1197636.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Planetary Science Institute, Tucson, AZ 85719, USA. cjhansen@psi.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21292976" target="_blank"〉PubMed〈/a〉
Keywords:
*Carbon Dioxide
;
Dry Ice
;
Extraterrestrial Environment
;
*Mars
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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