Valleys associated with light-toned layered deposits in several locations along the plateaus adjacent to the largest canyon system on Mars suggest low-temperature alteration of volcanic rocks by acidic water both before and after formation of the canyons.

The youngest flood-lava flow on Mars, found in the Elysium Planitia region and covering an area the size of Oregon, is the product of a single eruption and was put in place turbulently over a span of several weeks at most.

New details are observed in how seasonal vanishing of carbon-dioxide ice sheets in far-southern latitudes imprints the ground with fan-shaped and spider-shaped patterns via venting of carbon-dioxide gas from the undersurface of the ice.