Publication Date:
2009-09-26
Description:
New impact craters at five sites in the martian mid-latitudes excavated material from depths of decimeters that has a brightness and color indicative of water ice. Near-infrared spectra of the largest example confirm this composition, and repeated imaging showed fading over several months, as expected for sublimating ice. Thermal models of one site show that millimeters of sublimation occurred during this fading period, indicating clean ice rather than ice in soil pores. Our derived ice-table depths are consistent with models using higher long-term average atmospheric water vapor content than present values. Craters at most of these sites may have excavated completely through this clean ice, probing the ice table to previously unsampled depths of meters and revealing substantial heterogeneity in the vertical distribution of the ice itself.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Byrne, Shane -- Dundas, Colin M -- Kennedy, Megan R -- Mellon, Michael T -- McEwen, Alfred S -- Cull, Selby C -- Daubar, Ingrid J -- Shean, David E -- Seelos, Kimberly D -- Murchie, Scott L -- Cantor, Bruce A -- Arvidson, Raymond E -- Edgett, Kenneth S -- Reufer, Andreas -- Thomas, Nicolas -- Harrison, Tanya N -- Posiolova, Liliya V -- Seelos, Frank P -- New York, N.Y. -- Science. 2009 Sep 25;325(5948):1674-6. doi: 10.1126/science.1175307.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. shane@lpl.arizona.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19779195" target="_blank"〉PubMed〈/a〉
Keywords:
Extraterrestrial Environment
;
*Ice
;
*Mars
;
Meteoroids
;
Temperature
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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