Fig. 1
From: Reversing Dune
Reversing slip faces containing bright material on double-sided (sigmoidal) barchan dunes in Proctor Crater, Mars. (a) MOC NA M1900307 during the fall (Ls = 45°) and (b) MOC NA E0902707 during the spring (Ls = 263°) show the same area with bright accumulations on opposing slip faces (Fenton et al. 2005) (NASA/JPL/MSSS)