Light-Toned Rock in Southern Highlands
Light-Toned Rock in Southern Highlands
PSP_006962_1520  Science Theme: Geologic Contacts/Stratigraphy
This image shows a broad expanse of rock in the southern highlands of Mars. This outcrop is located on the floor of a large, old impact crater, now partially filled in, and shows the nature of some of the infilling material.

At large scale, the outcrop shows a series of linear aligned ridges. These are yardangs, formed by aeolian (wind) erosion. As the wind erodes the rock, it shapes it into aerodynamic forms. At smaller scale, the wind has carved fine grooves and scallops into the rock surface, aligned in the same direction as the large yardangs.

At full resolution, the rock is heavily fractured. At many sites, the rock is breaking into angular boulders. The largest cracks appear to have developed into shallow troughs, since they are weak sites which are most easily eroded. Troughs and other low areas have been filled by wind-blown sand or dust.

One possible source for this rock is volcanic ash. The outcrop lies between Hadriaca Patera and Tyrrhena Patera, two ancient volcanoes. These volcanoes appear different from the giant shield volcanoes like Olympus Mons; it has been suggested that they erupted more explosively, while the large shields were built mostly by lava flows.

Written by: Colin Dundas  (3 March 2008)
Acquisition date
20 January 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
257.7 km (160.2 miles)

Original image scale range
from 26.0 cm/pixel (with 1 x 1 binning) to 52.1 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
20.5°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  42.5°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (893MB)

IRB color
map-projected   (476MB)

Black and white
map-projected  (464MB)
non-map           (380MB)

IRB color
map projected  (172MB)
non-map           (439MB)

Merged IRB
map projected  (261MB)

Merged RGB
map-projected  (252MB)

RGB color
non map           (451MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

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.