12.13.2016 Now and Long Ago at Gale Crater, Mars
12.13.2016 Where's Boron? Mars Rover Detects It
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
03.30.2016 Erisa Hines
03.30.2016 Buzz Aldrin
02.12.2016 Women in Science
02.09.2016 Adam Steltzner, a JPL engineer
01.27.2016 Night Close-up of Martian Sand Grains
01.27.2016 Curiosity Self-Portrait at Martian Sand Dune
12.17.2015 Alteration Effects at Gale and Gusev Craters
12.17.2015 Full-Circle View Near 'Marias Pass' on Mars
12.11.2015 Surface Close-up of a Martian Sand Dune
12.11.2015 Martian Sand Disturbed by Rover Wheel
11.24.2015 Carbon Exchange and Loss Processes on Mars
11.17.2015 Chemical Laptop 1
Minerals at 'Rocknest' and 'John Klein' (Unannotated)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 annotated version.
Image Credit: NASA/JPL-Caltech/Ames