Chasma Boreale (1)

This is an image of the North Polar Layered Deposits (NPLD) near the source Region of Chasma Boreale. Chasma Boreale is the largest re-entrant trough in the NPLD, with its head region located roughly 300 Km from the North Pole and its mouth opening into the Northern Plains at the perimeter of the NPLD. Chasma Boreale is thought to have formed due to outflow of water from underneath the Polar Cap, or due to winds blowing off the Polar Cap, or a combination of both.
Investigation of the currently visible layers around the source region may tell us if they have been deformed and down-dropped, perhaps by melting and flow of water beneath, or if they remain undisturbed. Layers here do not appear as fine as elsewhere in polar trough exposures, although this may be due to the relatively gently sloping exposure here.