Volcanic and Clay Materials Near Nili Fossae
Volcanic and Clay Materials Near Nili Fossae
PSP_007055_2015  Science Theme: Seasonal Processes
This image is located west of the Nili Fossae trough, one of the proposed landing sites for the Mars Science Laboratory. Here, we combine information from two other MRO instruments, the Context Camera (CTX) and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), to provide insight into the geology of the region.

The first subimage shows the CTX image, with the HiRISE footprint shown in yellow. This footprint covers dark and light terrain. Looking at the HiRISE image, the dark terrain is fairly featureless in some areas, whereas other parts, when zoomed in to high resolution, show ripples, sand deposits resulting from wind activity. The lighter terrain is bedrock.

Zooming in, this material commonly has a polygonal texture. The second subimage shows the HiRISE footprint with the location, shown as a red rectangle, of a color enhanced portion of the image; this color product is visible here. It combines HiRISE’s blue-green, red, and infrared filters and is enhanced to bring out detail.

By folding in data from CRISM, we can correlate the colors to materials and composition. The green and bluish colors represent a composition rich in mafic (iron- and magnesium-rich) minerals such as pyroxene and maybe olivine, with green having the greatest concentration. The green-blue material at the upper right is mostly rock, whereas the materials in the bedforms (at left) are composed of sand. The reddish materials are composed of magnesium- and iron-rich clays, possibly formed by ancient water that altered volcanic rock. In this scenario, the polygonal texture could represent cracks formed after the clays dried. CRISM also detects minor amounts of clay in the green and blue units.

Written by: Nathan Bridges  (25 June 2008)
Acquisition date
28 January 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
280.5 km (174.4 miles)

Original image scale range
28.1 cm/pixel (with 1 x 1 binning) so objects ~84 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
39°, with the Sun about 51° above the horizon

Solar longitude
23.8°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  354.6°
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   (692MB)

IRB color
map-projected   (300MB)

Black and white
map-projected  (332MB)
non-map           (349MB)

IRB color
map projected  (109MB)
non-map           (275MB)

Merged IRB
map projected  (182MB)

Merged RGB
map-projected  (174MB)

RGB color
non map           (278MB)
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.