Gullies on Pole-Facing Slope and Arcuate Ridges on Crater Floor
Gullies on Pole-Facing Slope and Arcuate Ridges on Crater Floor
ESP_011995_1410  Science Theme: Fluvial Processes
This Southern hemisphere crater has gullies on its North and Northeast walls. Gullies are proposed to be carved by liquid water originating from the subsurface or melting ice/snow on the surface.

Arcuate ridges, wave-shaped high-standing features, are located downslope of the gullies here. This happens frequently on Mars, although it is unknown whether the formation of gullies and arcuate ridges are related to each other.

Dark dunes are visible on the crater floor. Lighter, smaller dunes rim the south side of the crater floor. The entire scene has a pitted texture, suggesting that ground ice was once present in this region. When ground ice sublimates (goes from a solid directly to a gas), it leaves behind empty spaces in the soil that turn into pits as the remaining overlying soil collapses to fill them.

Written by: Kelly Kolb  (25 March 2009)

This is a stereo pair with ESP_012496_1410.
Acquisition date
16 February 2009

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
254.4 km (158.1 miles)

Original image scale range
25.6 cm/pixel (with 1 x 1 binning) so objects ~77 cm across are resolved

Map projected scale
25 cm/pixel and North is up

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Phase angle

Solar incidence angle
58°, with the Sun about 32° above the horizon

Solar longitude
210.8°, Northern Autumn

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North azimuth:  97°
Sub-solar azimuth:  14.9°
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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.