Banded Terrain in Hellas Planitia

This image shows a portion of an enigmatic formation called banded terrain, which is only observed in the northwest of the Hellas basin. This basin was formed by a giant impact around 4 billion years ago. It is the deepest impact basin on the planet, and banded terrain is in the deepest part of the basin (at elevations around 7 kilometers).

This terrain is characterized by smooth bands of material separated by ridges or troughs, with circular and lobe shapes that are typically several kilometers long and a few hundred meters wide. A closeup shows banded terrain deforming around a mesa (bottom) and the transition of smooth banded terrain into surrounding rough terrain (top).

Other banded terrain appears to have undergone deformation, like by a glacier, though it is not quite like terrestrial landforms. There are several ideas for what it could be, including a thin, flowing, ice-rich layer or sediment that was deformed beneath a former ice sheet.

The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. (The original image scale is 51.1 centimeters [20.1 inches] per pixel [with 2 x 2 binning]; objects on the order of 153 centimeters [60.2 inches] across are resolved.) North is up.

The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.