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Viking 1 examines Mars’ Ophir Chasma

Posted by Bridget in Space

During its examination of Mars, the Viking 1 spacecraft returned images of Valles Marineris, a huge canyon system 5 000km long, whose connected chasma or valleys may have formed from a combination of erosional collapse and structural activity. This synthetic oblique view shows Ophir Chasma, the northern most one of the connected valleys of Valles Marineris. For scale, the large impact crater in lower right corner is about 30km, wide. Ophir Chasma is a large west-northwest-trending trough about 100km wide. The Chasma is bordered by high-walled cliffs, most likely faults, that show spur-and-gully morphology and smooth sections. The walls have been dissected by landslides forming re-entrants. The volume of the landslide debris is more than 1 000 times greater than that from the 18 May 1980, debris avalanche from Mount St. Helens. The longitudinal grooves seen in the foreground are thought to be due to differential shear and lateral spreading at high velocities.

(Image: NASA/JPL/USGS)