Each of these four panels shows a close-up view of a different type of
geological deposit formed with the involvement of water, based on
observations by NASA's Mars Reconnaissance Orbiter. All four date from the
earliest period of Martian history, called the Noachian Period.
The upper-left panel shows carbonates overlying clays in the Nili Fossae
region of Mars. The view combines color-coded information from infrared
spectral observations by the Compact Reconnaissance Imaging Spectrometer
for Mars (CRISM) with an underlying black-and-white image from the High
Resolution Imaging Science Experiment (HiRISE) camera. 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).
The upper-right panel shows phyllosilicates and chlorides in the Terra
Sirenum region, observed by CRISM and HiRISE. Medium-toned, finely
fractured rocks containing chloride salts either underlie higher-standing,
light-toned phyllosilicates or fill in low spots between them. Both sit on
dark, eroded volcanic material.
The lower-left panel shows the upper portion of canyon wall in Coprates
Chasma, observed by HiRISE and CRISM. The chasm rim cuts across the middle
of the image. The wall slopes down to the top of the image and continues
outside the region shown, exposing multiple phyllosilicate-bearing layers
in a section of rock 7 kilometers (4 miles) thick. Two of the layers shown
here are finely fractured aluminum clays that dominate the lower half of
the image, underlain by thin beds of iron-magnesium clays at the top of
the image. The dark material is a remnant of an overlying layer of
basaltic sand that has been partly eroded away by the wind.
The lower-right panel shows phyllosilicates with vertically layered
compositions in Mawrth Vallis, observed by HiRISE (presented in enhanced
color) and CRISM. The brown-colored knob in the middle of the scene is a
remnant of cap rock that overlies aluminum clays (blue-gray), which in
turn overlie iron-magnesium clays (buff).
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.
