Landslides in Valles Marineris commonly include extensive debris aprons like this, which extends about 40 kilometers from the base of the wall. The longest known debris apron in the Valles Marineris extends ~ 100 kilometers. This debris apron here appears to have formed by collapse of the slump blocks at the base of the wall. The ridges on the surface of the apron, radiating from the landslide's source, may indicate that it traveled very fast, probably more than 100 km/hr. The landslides in Gangis Chasma (as in the rest of the Valles Marineris) show few meteorite impact craters, and so are quite young; they probably formed in the Amazonian Epoch of Mars' history.