Pumice and lithic clasts from gravel-mantled megaripples in the Argentinean Puna, an analog to Martian large ripples and Transverse Aeolian Ridges (TARs), were put in a boundary layer wind tunnel to derive threshold speeds for various stages of motion of the component clasts and observe incipient bedform development. Combined with results from a field meteorological station, it is found that the gravel components can initially only move under gusty conditions, with the impact of saltating pumice and sand lowering threshold. Pumices can saltate without the impact of sand, implying that they are both an impelling force for other pumices and lithics, and are the most likely clast constituent to undergo transport. Accumulation into bedforms in ...