Ridges in Huo Hsing Vallis
Ridges in Huo Hsing Vallis
PSP_008189_2080  Science Theme: Tectonic Processes
This image features a series of long and somewhat linear ridges in the Huo Hsing Vallis region of Mars.

These ridges appear to have formed as a result of erosion of the surrounding rock. The ridges themselves are likely stronger material and therefore stayed behind as the remainder of the rock was whittled away, possibly by flowing water, blowing wind, or a combination of both.

If water played a role in the erosion of the rock and exposure of these ridges, this water would have flowed many thousands or millions of years ago, perhaps through Huo Hsing Vallis. Water underground may also have helped to form these ridges prior to erosion. On Earth, water and other fluids flowing underground often follow cracks and faults, since it is easier for the liquids to flow through the open spaces of these fractures than through solid rock. These liquids often leave behind minerals within the fractures that help to strengthen the surrounding rock by essentially gluing the fragments of rock together. This can make the fracture stronger than the surrounding rock and lead to ridges that withstand the forces of erosion.

Similar cemented fractures have also been interpreted elsewhere on Mars, and if true, would be useful indicators of the presence of underground water at some point in the planet’s past.

Written by: Chris Okubo  (21 May 2008)

This is a stereo pair with PSP_007833_2080.
Acquisition date
25 April 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
283.6 km (176.2 miles)

Original image scale range
28.4 cm/pixel (with 1 x 1 binning) so objects ~85 cm across are resolved

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25 cm/pixel and North is up

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42°, with the Sun about 48° above the horizon

Solar longitude
63.5°, Northern Spring

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Sub-solar azimuth:  8.7°
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NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.