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Concentrated perchlorate at the Mars Phoenix landing site: Evidence for thin film liquid water on Mars
Author(s) -
Cull Selby C.,
Arvidson Raymond E.,
Catalano Jeffrey G.,
Ming Douglas W.,
Morris Richard V.,
Mellon Michael T.,
Lemmon Mark
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045269
Subject(s) - perchlorate , mars exploration program , phoenix , geology , astrobiology , dissolution , liquid water , geomorphology , mineralogy , environmental science , ion , archaeology , chemistry , earth science , geography , physics , organic chemistry , metropolitan area
NASA's Phoenix mission, which landed on the northern plains of Mars in 2008, returned evidence of the perchlorate anion distributed evenly throughout the soil column at the landing site. Here, we use spectral data from Phoenix's Surface Stereo Imager to map the distribution of perchlorate salts at the Phoenix landing site, and find that perchlorate salt has been locally concentrated into subsurface patches, similar to salt patches that result from aqueous dissolution and redistribution on Earth. We propose that thin films of liquid water are responsible for translocating perchlorate from the surface to the subsurface, and for concentrating it in patches. The thin films are interpreted to result from melting of minor ice covers related to seasonal and long‐term obliquity cycles.