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12.13.2016 Now and Long Ago at Gale Crater, Mars
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11.15.2016 Schiaparelli Impact Site on Mars, Stereo
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10.17.2016 MAVEN Captures Rapid Cloud Formation
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10.05.2016 Dust Haze Hiding the Martian Surface in 2001
10.04.2016 Test of Lander Vision System for Mars 2020
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10.03.2016 Curiosity Self-Portrait at 'Murray Buttes'
10.03.2016 Butte 'M9a' in 'Murray Buttes' on Mars
09.19.2016 Ribbon Cutting
09.09.2016 Farewell to Murray Buttes (Image 5)
09.09.2016 Farewell to Murray Buttes (Image 4)
09.09.2016 Farewell to Murray Buttes (Image 3)
09.09.2016 Farewell to Murray Buttes (Image 2)
09.09.2016 Farewell to Murray Buttes (Image 1)
08.26.2016 Out-of-this-World Records
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08.04.2016 Mars Rover Social Media Game
08.02.2016 Artist Concept for RIMFAX
07.20.2016 Viking 40 Year Anniversary Artwork: Medal
07.18.2016 Mars 2020 Range Trigger
07.14.2016 NASA to Launch Mars Rover in 2020
Minerals at 'Rocknest' and 'John Klein'This side-by-side comparison shows the X-ray diffraction patterns of two different samples collected from the Martian surface by NASA's Curiosity rover. These images, made from data obtained by Curiosity's Chemistry and Mineralogy instrument (CheMin), show the patterns obtained from a drift of windblown dust and sand called "Rocknest" and from a powdered rock sample drilled from the "John Klein" bedrock.
The presence of abundant clay minerals in the John Klein drill powder and the lack of abundant salt suggest a fresh water environment. The presence of calcium sulfates rather than magnesium or iron sulfates (as found at Meridiani Planum by NASA's Mars Exploration Rover Opportunity) suggests a neutral to mildly alkaline pH environment. The Rocknest sand shadow mineralogy suggests a dry, aeolian (wind-shaped) environment with low water activity. The John Klein mineralogy suggests a lacustrine (lakebed) environment with high water activity. As seen on the left, the Rocknest data reveal abundant plagioclase feldspar, pyroxene and olivine minerals. The data also indicate reveal small amounts of magnetite and anhydrite. In addition, the Rocknest sample contains 25 to 35 percent amorphous, or non-crystalline, material.
X-ray diffraction analysis of the John Klein drill powder reveals abundant phyllosilicate (a class of clay minerals called smectites that form by the action of relatively pure and neutral pH water on source minerals), plagioclase feldspar, pyroxene, magnetite and olivine. Alternatively, the clay minerals could have been transported by water from sources higher up the sediment fan to form the John Klein mineral assemblage. The region of the pattern indicating the phyllosilicates is labeled in the annotated version of this image. The data also show minor amounts of anhydrite and bassanite. The John Klein sample also contains about 20 percent amorphous material.
See the unannotated version.
Image Credit: NASA/JPL-Caltech/Ames