Active boulder movement at high Martian latitudes

Lobate stony landforms occur on steep slopes at high latitudes on Mars. We demonstrate active boulder movement at seven such sites. Submeter-scale boulders frequently move distances of a few meters. The movement is concentrated in the vicinity of the lobate landforms but also occurs on other slopes. This provides evidence for a newly discovered, common style of activity on Mars, which may play an important role in slope degradation. It also opens the possibility that the lobate features are currently forming in the absence of significant volumes of liquid water. Plain Language Summary Tongue-shaped lobes of boulders occur on steep slopes at high latitudes on Mars. Boulders in those lobes, as well as on nearby slopes, commonly move short distances. Several processes could contribute to moving the boulders, but liquid water is probably not involved. This is a new type of active surface process on Mars and may be an important contributor to forming the lobes or changing steep slopes.