Dark slope streaks on Mars: Are aqueous processes involved?

Concentrations of dark slope streaks occur in the equatorial latitudes of Mars, mostly where magmatic-driven activity dominates the geologic record. Although originally ascribed to wet debris flows, all the most recent published hypotheses concerning these features focus on processes which disturb a brighter dusty mantle to expose a darker substrate. These mechanisms invoke dry mass wasting or eolian processes, excluding a role for water. In light of the geographic, geologic, and morphologic considerations, and the new information provided from the Mars Orbital Camera and the Mars Orbital Data Altimeter, we reexamine fluvial processes as a viable explanation for some of the dark slope streaks. In our opinion, two contrasting processes for the formation of dark slope streaks, dust avalanching and spring discharge, represent endpoints on a continuum of progenitors. It may be that some of these features result from dry mass wasting or eolian processes, some from fluvial processes, and some from a mechanism(s) not yet conceived. A spring discharge origin for the formation of the dark slope streaks has profound implications, including Mars having limited, but currently active, fluvial processes acting upon its surface, as well as near-surface aquifers.