The two linear depressions in this image form part of the Elysium Fossae complex, a group of troughs located in the Elysium quadrangle of Mars.
These troughs are tectonic features, likely formed by the stretching, tearing and subsequent collapse of the crust resulting from the rise of the nearby Elysium volcanic province. The north and south troughs in this image are roughly 4.8 and 3.7 kilometers across respectively, and around 800 meters deep. Strata, or layering from successive deposition of material (likely ash and lava), are exposed in the… [More at link]