Gullies and Lobate Material in a Crater in the Nereidum Montes
Gullies and Lobate Material in a Crater in the Nereidum Montes
ESP_020786_1420  Science Theme: Fluvial Processes
This image includes a crater that has been heavily influenced by later geologic processes.

First of all, terrain-altering or -burying processes have eliminated much of the pattern of ejecta that surrounds fresh craters. The crater also appears fairly flat-floored with short walls (not very deep) for its size, indicating material has filled it in. These modifying effects may be due to deposition and activity of ice-rich or other mantling sediments deposited at some point in the past.

Finally, the crater clearly exhibits gullies starting on its northern wall and extending to its center. The arc-shaped ridge inside the southern edge of the crater, partially buried by the filling material, is particularly curious - it could be a wind-caused or other accumulation of crater-fill material.

One of the rationales for acquiring an image of this location is to investigate the relationship between these features; HiRISE's full resolution can provide better details of the terrain.

Written by: Patrick Russell  (1 February 2011)

This is a stereo pair with ESP_014127_1420.
Acquisition date
02 January 2011

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
253.4 km (157.5 miles)

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from 27.2 cm/pixel (with 1 x 1 binning) to 54.4 cm/pixel (with 2 x 2 binning)

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25 cm/pixel and North is up

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54°, with the Sun about 36° above the horizon

Solar longitude
209.6°, Northern Autumn

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North azimuth:  93°
Sub-solar azimuth:  17.3°
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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.