Clay Minerals in Nili Fossae
Clay Minerals in Nili Fossae
PSP_007358_2015  Science Theme: Composition and Photometry
This false color RGB image shows the colorful diversity of hydrated minerals in Nili Fossae.

This region is near one of the proposed landing sites for the upcoming Mars Science Laboratory (MSL) rover. Though this view is not the same as what the human eye would see, it is clear from this image that there are many varieties of color that are attributed to variations in the minerals and rock types in this location.

The bright, light-toned bedrock is highly fractured and has been covered by reddish dust in some regions. There are also dunes that are forming in low spots around the knobs, or mesas, of rock. The CRISM instrument has also acquired images over this region and has shown that the rock in these mesas and knobs contain clay minerals, many of which contain iron and magnesium. These clay minerals also contain water.

One theory to explain the fractured rock is that some water was removed from the clays, causing them to contract, or shrink, and this caused the rock to break. This process is similar to the one that causes cracks to form in mud as it dries on Earth. However, there are other possible ways to form fractures and scientists are currently trying to understand which of these processes caused the fractures observed in the clays on Mars.

Written by: Ralph Milliken  (3 March 2008)

This is a stereo pair with PSP_008215_2015.
Acquisition date
20 February 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
280.4 km (174.3 miles)

Original image scale range
28.3 cm/pixel (with 1 x 1 binning) so objects ~85 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
34.7°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  1.6°
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   (1901MB)

IRB color
map-projected   (834MB)

Black and white
map-projected  (1069MB)
non-map           (1000MB)

IRB color
map projected  (348MB)
non-map           (741MB)

Merged IRB
map projected  (514MB)

Merged RGB
map-projected  (495MB)

RGB color
non map           (749MB)
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.