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Phyllosilicates in Nili Fossae
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Phyllosilicates in Nili Fossae

Acquired Date: March 10, 2008
Release Date: March 28, 2014
Latitude: 21.98 N
Longitude: 77.21 E
Keywords: Crater Interior/Rim/Ejecta, Fracture/Faults, Mafic minerals, Phyllosilicate minerals, Dichotomy Boundary
Parameters: BD2290 (Mg/Fe-OH minerals), D2300 (Fe-Mg phyllosilicates), OLINDEX3 (Olivine)

This image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Marsí crust is mostly made up of igneous rock and mafic materials, shown here with red denoting olivine. There are also aqueously-altered minerals in this scene, meaning minerals that have been changed by water. They are shown by the cyan and blue colors and most likely reflect the presence of iron/magnesium-containing phyllosilicates. Phyllosilicates, also known as sheet silicates, are comprised of microscopic crystal forms stacked in very thin layers.



This image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Marsí crust is mostly made up of igneous rock and mafic materials, shown here with red denoting olivine. There are also aqueously-altered minerals in this scene, meaning minerals that have been changed by water. They are shown by the cyan and blue colors and most likely reflect the presence of iron/magnesium-containing phyllosilicates. Phyllosilicates, also known as sheet silicates, are comprised of microscopic crystal forms stacked in very thin layers.

The group of olivine minerals is known to have the simplest crystalline structure of all the silicate minerals and form at very high temperatures. In hydrothermal situations, where both heat and water are present, olivine can be weathered down into clay minerals. This alteration can occur by leaching, where either the olivine absorbs different chemicals and water into its crystalline structure or by the silica that is present being removed.

Link to further description of the spectral parameters shown in this image can be found here.

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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