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Phyllosilicates on a scarp in Nili Fossae
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Phyllosilicates on a scarp in Nili Fossae

Acquired Date: February 8, 2008
Release Date: October 21, 2013
Latitude: 20.07 N
Longitude: 73.86 E
Keywords: Fracture/Faults, Hydrated Mineral, Layered Mineral, Phyllosilicate minerals, Dichotomy Boundary
Parameters: BD1900R/BD1950 (H2O), D2300 (Fe-Mg phyllosilicates), DOUB2190 (Kaolinite group)

This image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Here we see a layer of clay-like minerals called phyllosilicates that are found in many regions of Mars. Small occurrences of aluminum-rich phyllosilicates (shown in green) overly a layer of iron/magnesium-rich phyllosilicates (shown in magenta). In this image, faulting along the along the northwestern wall of the graben exposes the phyllosilicates from beneath their overlying layer of younger rock.



This image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Here we see a layer of clay-like minerals called phyllosilicates that are found in many regions of Mars. Small occurrences of aluminum-rich phyllosilicates (shown in green) overly a layer of iron/magnesium-rich phyllosilicates (shown in magenta). In this image, faulting along the along the northwestern wall of the graben exposes the phyllosilicates from beneath their overlying layer of younger rock.

The recurring pattern of aluminum-rich phyllosilicates overlying iron/magnesium-phyllosilicates is something that we see on Earth as well. Aluminum-rich phyllosilicates can form by leaching of soluble elements from soil, whereas iron/magnesium-rich phyllosilicates are closer in composition to the parent volcanic rock. This layering of minerals may imply that more soluble elements (like iron and magnesium) were leached from overlying rocks, creating a residue of aluminum-phyllosilicates overlying less-leached iron-magnesium phyllosilicates.

Link to further description of the spectral parameters shown in this image

Disclaimer: Colors shown here represent indicators of mineralogy and are not what the human eye would see.

Acknowledgements: THEMIS, MOLA, CRISM, Google Earth.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument also tracks seasonal variations in dust and ice aerosols in the Martian atmosphere, and water content in surface materials — leading to new understanding of the climate.

Credit: NASA/JPL/JHUAPL

   

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