Wet streaks in the McMurdo Dry Valleys, Antarctica: Implications for Recurring Slope Lineae on Mars

Recurring Slope Lineae (RSL) are dark streaks that seasonally propagate and fade on Martian slopes. The morphology dynamics of RSL suggest they might be brine flows; however, more recent hypotheses propose dry, granular flows. To determine if consistent with flows, we investigated Mars analog wet in Wright Valley Antarctica using new chemical analyses soils waters, time-lapse photography, satellite images. Results show the source water to is primarily local snowmelt, which percolates downslope. Meltwater leaches hygroscopic CaCl2-rich salts from underlying Ferrar dolerite bedrock. These accumulate at soil surfaces via evapoconcentration deliquesce/effloresce response daily relative humidity changes, causing surface brightness fluctuate. Over several years, active CaCl2 salt component back into subsurface leaving a residue less surface. Applied Mars, inconsistent expression RSL. Wet over multiple drain onto low angled slopes, have characteristic pattern downhill lateral edges. In contrast, seasonal features, terminate angle-of-repose typically appear monochromatic. inconsistencies provide evidence against flow formation.