The color coding on this composite image of an area about 3 kilometers (2
miles) across on Mars is based on infrared spectral information
interpreted as evidence of various minerals present. Carbonate (green) and
olivine-bearing rocks (yellow) occupy the same level in the stratigraphy,
and it is thought that the carbonate formed by involvement of water in
altering olivine-bearing rocks.
The scene is eroded terrain in the Nili Fossae region of northern Mars.
Beneath a rough-textured capping rock unit (purple) lie banded
olivine-bearing layers (yellow), which in some places have been partially
or wholly altered to carbonate (green). Beneath the olivine-and-carbonate
unit are rocks with iron-magnesium smectite clays (light blue). Olivine is
also found in sand dunes (near bottom right corner, for example), and it
probably eroded from the nearby rocks.
The image overlays the color-coded spectral information from the Compact
Reconnaissance Imaging Spectrometer for Mars (CRISM) onto a grayscale
image from the High Resolution Imaging Science Experiment (HiRISE) camera.
CRISM and HiRISE are two of the six science instruments on NASA's Mars
Reconnaissance Orbiter.
The infrared spectral information comes from a CRISM image catalogued as
FRT00003E12. The composite view here was made using 2.38-micrometer-wavelenghth
data as red, 1.80 micrometer as green and 1.15 micrometer as blue.
The base black-and-white image is catalogued as PSP_002888_2025 by the
HiRISE team.
NASA's Jet Propulsion Laboratory, a division of the California Institute
of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the
NASA Science Mission Directorate, Washington. Lockheed Martin Space
Systems, Denver, is the prime contractor for the project and built the
spacecraft. The Johns Hopkins University Applied Physics Laboratory led
the effort to build the CRISM instrument and operates CRISM in
coordination with an international team of researchers from universities,
government and the private sector. The University of Arizona, Tucson,
operates the HiRISE camera, which was built by Ball Aerospace &
Technologies Corp., Boulder, Colo.
