05.15.2017 From 'Tribulation' to 'Perseverance' on Mars
03.29.2017 A Decade of Compiling the Sharpest Mars Map
03.09.2017 Back-to-Back Martian Dust Storms
02.08.2017 Mars Reconnaissance Orbiter Observes Changes
01.25.2017 'Wing' Dike of Hardened Lava in New Mexico
01.25.2017 Blade-Like Martian Walls Outline Polygons
01.06.2017 Earth and Its Moon, as Seen From Mars
11.15.2016 Schiaparelli Impact Site on Mars, Stereo
11.03.2016 Schiaparelli Impact Site on Mars, in Color
03.30.2016 Erisa Hines
03.30.2016 Buzz Aldrin
03.21.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 For a Decade Orbiting Mars: One Recent View
03.09.2016 Mars Reconnaissance Orbiter By the Numbers
03.01.2016 MRO sees Frosty Spring Slopes
02.12.2016 Women in Science
02.10.2016 Wind at Work
11.16.2015 Change Observed in Martian Sand Dune
10.05.2015 'The Martian' Story's Ares 4 Landing Site
10.05.2015 The Ares 3 Landing Site (Figure A)
09.30.2015 Avalanche Ho!
06.29.2015 Mars Exploration Zone Layout Considerations
06.17.2015 Active High-Latitude Dune Gullies
06.03.2015 Crisp Crater in Sirenum Fossae
05.20.2015 Sedimentary Rock Layers on a Crater Floor
05.20.2015 Honey, I Shrunk the Mesas
05.11.2015 Icy Wonderland
05.04.2015 Diverse Orbits Around Mars
03.27.2015 South Pole Spiders
03.27.2015 A Smile a Day....
03.25.2015 Pitted Landforms in Southern Hellas Planitia
03.12.2015 Curiosity Heading Away from 'Pahrump Hills'
02.18.2015 Lava Flow Near the Base of Olympus Mons
02.09.2015 Yardangs in Arsinoes Chaos, Mars
02.04.2015 Curiosity Rover at 'Pahrump Hills'
01.22.2015 Frost on Crater Slope
Clay Minerals in Craters and Escarpments on MarsImpact cratering and erosion combine to reveal the composition of the Martian underground by exposing materials from the subsurface. Investigation of exposed clay minerals at thousands of Martian sites by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter suggests a long period of wet, warm conditions, mostly underground.
Infrared light indicates terrains of different composition in false-color infrared images (top) of a crater (left) and an escarpment (right). Each of the scenes is about 6 miles (10 kilometers) wide. The lower images of the same sites show how distinctive absorption bands permit identification and mapping of specific minerals. In the lower images, iron-magnesium clays are mapped in blue. These are the most common clays on Mars, occupying large sections of the deep crust and mostly formed by subsurface water. These clays are beneath unaltered volcanic layers that contain the mineral olivine (green). The site shown in the image on the right also contains aluminum clays (red), which formed by waters near the surface. These clays are uncommon on Mars but are sometimes located on top of iron-magnesium clays in a distinctive stratigraphy, indicating formation later in time.
These two example sites, out of thousands where CRISM has observed clay minerals, are at 10.65 degrees south latitude, 98.22 degrees east longitude (left pair) and 22.06 degrees north latitude, 74.63 degrees east latitude (right pair).
In the top two images, the false color comes from presenting observed brightnesses in three different wavelengths of invisible infrared wavelengths -- 2,529 nanometers, 1,506 nanometers and 1,080 nanometers -- as red, green and blue, respectively, composited into color images.
In the bottom two images, colors are assigned to absorption-band characteristics: infrared frequencies at which the materials on the Mars surface are less bright compared to their brightness at other frequencies. The data presented as red are pixel-by-pixel absorption-band depths at 2,210 nanometers, the data presented as green are broad absorption-band depths near 1,000 nanometers, and the data presented as blue are the absorption-band depths at 2,300 nanometers. These color data were then overlain and merged with the brightness at 770 nanometers to show the relationship of detected minerals with underlying topography. For more information on mineral mapping and more CRISM images, see http://crism-map.jhuapl.edu .
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, 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.
Image Credit: NASA/JPL-Caltech/JHUAPL