Gullies and Curved Ridges at the Base of Crater Walls
Gullies and Curved Ridges at the Base of Crater Walls
ESP_023328_1325  Science Theme: Glacial/Periglacial Processes
This crater is typical of other small craters in the southern mid-latitudes, containing both gullies on its walls and wavy (arcuate) ridges at the base of the walls.

These features appear inter-related and their orientation on the crater wall can be associated with the latitude of the crater. Craters at latitudes between about -30 and -44 degrees (in the Southern Hemisphere) typically have pole-facing gullies and curved ridges. Craters at latitudes between -44 degrees and -60 degrees (as is this one at -47 degrees) typically have these features on equator-facing walls, or on the east and west walls. This is thought to relate to changes in the obliquity of Mars.

These features likely formed during a period of high obliquity (tens of millions of years ago). During this time, it is thought that snowfall was deposited in these mid-latitude regions, and the high tilt of the planet led to higher degrees of solar insolation on the different crater walls, causing the snow to melt and form gullies. The arcuate ridges are thought to be moraines, or remnants of snow-packed ice flowing down the crater wall and onto the crater floor.

Written by: Dan Berman  (28 September 2011)

This is a stereo pair with ESP_023750_1325.
Acquisition date
19 July 2011

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
250.9 km (155.9 miles)

Original image scale range
25.1 cm/pixel (with 1 x 1 binning) so objects ~75 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
46°, with the Sun about 44° above the horizon

Solar longitude
330.5°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  44.3°
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