Eroded Sediments in West Candor Chasma
Eroded Sediments in West Candor Chasma
PSP_009460_1745  Science Theme: Sedimentary/Layering Processes
This image shows a steep-sided depression in light-toned, layered rocks in the Valles Marineris canyon system. This formation, known as Ceti Mensa, is located in western Candor Chasma in the northern Valles.

The origin of Ceti Mensa and other layered deposits within the canyons is a source of much debate: proposed interpretations include lake deposits, deposits of volcanic ash, deposits of windblown sand and dust, and glacial deposits. Recent spectral observations by the Mars Express and Mars Reconnaissance Orbiter spacecraft have identified crystalline iron oxides and hydrated magnesium sulfate minerals on Ceti Mensa. These minerals are regarded as indicators of the presence of liquid water during their formation. The hydrated sulfate mineral kieserite, in particular, most commonly forms on Earth by evaporation of brines.

This image gives another clue to the formation of Ceti Mensa. Close-up examination shows fine banding in the layers of Ceti Mensa that is exposed by the ongoing erosion. The banding is produced by alternating bright and dark material. The thickness of the individual bands ranges from a few meters down to the resolution limit of the image, a few tens of centimeters. The bands are parallel, although they appear wavy on the irregular, eroded surface.

The banding visible in this image most closely resembles terrestrial lake deposits and similar rocks formed in aqueous, low energy depositional environments. Structures such as cross-bedding that are hallmarks of wind-deposited sediments are absent, as are cobbles and clasts that are typical of glacial sediments.

If this interpretation is correct, the thickness of Ceti Mensa suggests formation in standing bodies of water that were several kilometers deep.

Written by: Paul Geissler  (8 October 2008)

This is a stereo pair with ESP_017741_1745.
Acquisition date
02 August 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
266.0 km (165.3 miles)

Original image scale range
27.8 cm/pixel (with 1 x 1 binning) so objects ~83 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
57°, with the Sun about 33° above the horizon

Solar longitude
107.2°, Northern Summer

For non-map projected images
North azimuth:  99°
Sub-solar azimuth:  40.0°
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   (769MB)

IRB color
map-projected   (331MB)

Black and white
map-projected  (393MB)
non-map           (383MB)

IRB color
map projected  (128MB)
non-map           (312MB)

Merged IRB
map projected  (197MB)

Merged RGB
map-projected  (189MB)

RGB color
non map           (302MB)
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph details page

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.