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2612276 
Journal Article 
Spectral constraints on the composition of low-albedo slope streaks in the Olympus Mons Aureole 
Mushkin, A; Gillespie, AR; Montgomery, DR; Schreiber, BC; Arvidson, RayE 
2010 
Yes 
Geophysical Research Letters
ISSN: 0094-8276
EISSN: 1944-8007 
37 
WOS:000284479300001 
Slope-streak formation is one of the most active surface phenomena presently observed in equatorial Mars. Here, we use for the first time color HiRISE and hyperspectral CRISM images to characterize the spectral properties of individual slope streaks formed during the past decade in the Olympus Mons Aureole, constrain their composition, and discriminate between 'spectrally permissible' formation hypotheses. The slope streaks investigated form a spectrally distinct class of active surface features with a compositional uniqueness that is inconsistent with previously suggested slope-streak formation mechanisms, such as exposure of pre-existing substrate, persistent soil moisture, or textural effects alone. Instead, a dry transparent surface coating and/or effective enrichment in low-albedo ferric oxides emerge as the most likely surface coloring mechanisms. This raises the intriguing possibility that the spectrally unique class of slope streaks identified here may represent low-volume seeps of brines that evaporate shortly after their emergence, leaving behind dry and diagenetically 'stained' surfaces.