Gullies and Seasonal Frost in a Crater
Gullies and Seasonal Frost in a Crater
ESP_018709_1445  Science Theme: Mass Wasting Processes
This scene shows the curving, eastern interior walls of a 12 kilometer-diameter (approximately 7.4 mile-diameter) impact crater in the Southern mid-latitudes of Mars.

The sun is off-scene to the northwest (left in the map-projected images), causing the northwestern wall to cast a shadow far into the deep crater interior. This shadowing effect also highlights the gullies incised into the northern wall of the crater. Many ideas have been advanced as to how such gullies form—some appear to have involved flowing water, perhaps from melting ice, while others appear to be formed solely due to mass wasting of soil and rocks.

In the enhanced-color strip down the middle of this image, the northern wall displays some bluish-purplish coating, which is seasonal frost that remains deposited on such steep slopes facing away from the equator at this time of year, much like frost often accumulates first, or disappears last, from mountain slopes on Earth that face away from the equator (north-facing in the Northern Hemisphere, and south-facing in the Southern Hemisphere).

Written by: Patrick Russell  (1 September 2010)
Acquisition date
24 July 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
252.0 km (156.6 miles)

Original image scale range
50.4 cm/pixel (with 2 x 2 binning) so objects ~151 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
76°, with the Sun about 14° above the horizon

Solar longitude
122.7°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  45.5°
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   (124MB)

IRB color
map-projected   (67MB)

Black and white
map-projected  (60MB)
non-map           (62MB)

IRB color
map projected  (21MB)
non-map           (64MB)

Merged IRB
map projected  (106MB)

Merged RGB
map-projected  (101MB)

RGB color
non map           (63MB)
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.