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Formation of recurring slope lineae by liquid brines on present‐day Mars
Author(s) -
Chevrier Vincent F.,
RiveraValentin Edgard G.
Publication year - 2012
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 - 10.1029/2012gl054119
Subject(s) - mars exploration program , equator , martian , geology , orbiter , seasonality , tharsis , geophysics , atmospheric sciences , astrobiology , latitude , geodesy , physics , statistics , mathematics , astronomy
Recurring Slope Lineae (RSL) are small scale seasonal flow features identified by Mars Reconnaissance Orbiter that present several interesting characteristics such as an albedo contrast, seasonal dependence, and a strong preference for equator‐facing slopes. All of these characteristics strongly suggest a thermally driven mechanism such as a liquid triggered or dominated flow. Here we investigate the possibility that these features are formed by melting of brines of various compositions via a combination of thermodynamic and kinetic numerical models. Results suggest that a solution with a freezing temperature of ∼223 K can best reproduce the observed seasonality. Relatively high surface evaporation rates at the RSL locations make the flows quickly disappear over a single season. Our model reproduces well the seasonality of RSL and can explain the preference for equator‐facing slopes suggesting that brine flows, and therefore liquids, are possible on a small time and space scale today on Mars. However, if the RSL are indeed formed by brines, it may indicate that a recharge mechanism is active in order to maintain a source of brine over even short geological timescales, which would have important implications for the Martian water cycle.