Flood Carved Rock
Flood Carved Rock
ESP_012270_2035  Science Theme: Fluvial Processes
This HiRISE image is part of the Olympica Fossae in the Tharsis region of Mars.

Tharsis is most famous for being the home of the four largest volcanoes in the Solar System. However, the region also hosts a variety of other geologic features formed as the ground deformed under the tremendous weight of the volcanoes.

Most of the fissures (or "fossae") in the region are primarily places where the ground was pulled apart. However, the Olympica Fossae are somewhat different. They are oriented at an angle to the other fissures suggesting that some other process was important in their formation. A close-up image reveals that erosion by one or more catastrophic floods may have played a key role.

The teardrop shaped islands and the parallel ridges are rock left standing after the flood erosion. However, the deepest depression running basically east-west through the middle of the image was probably caused by tectonic extension, not flood erosion. This juxtaposition of tectonic and flood-carved valleys is visible elsewhere on Mars, suggesting that it may be common for the tectonic fracturing to release copious volumes of subterranean water.

Written by: Laszlo P. Keszthelyi  (15 April 2009)

This is a stereo pair with ESP_012547_2035.
Acquisition date
09 March 2009

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
277.5 km (172.5 miles)

Original image scale range
29.9 cm/pixel (with 1 x 1 binning) so objects ~90 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
65°, with the Sun about 25° above the horizon

Solar longitude
224.0°, Northern Autumn

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  331.4°
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RGB color
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Full resolution JP2 download
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IRB: infrared-red-blue
RGB: red-green-blue
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Black & white is 5 km across; enhanced color about 1 km
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

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.