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Magnesium Carbonate in Nili Fossae
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Magnesium Carbonate in Nili Fossae

Acquired Date: June 11, 2008
Release Date: September 20, 2013
Latitude: 21.93 N
Longitude: 78.42 E
Keywords: Crater Interior/Rim/Ejecta, Fracture/Faults, Carbonate Mineral, Hydrated Mineral, Mafic minerals, Dichotomy Boundary
Parameters: BD2500H2 (Mg-carbonates), D2300 (Fe-Mg phyllosilicates), OLINDEX3 (Olivine)

This CRISM image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Olivine-rich igneous rocks appear red, chemically altered rocks rich in iron/magnesium-containing clay-like minerals called phyllosilicates in green, and small exposures of carbonate minerals in light yellow or white. Olivine is present in many places on Mars and demonstrates that volcanism played a primary role in forming Marsí crust. Phyllosilicates, a family of clay-like minerals, demonstrate the presence of water early in Marsí history. Carbonate minerals were first found on Mars using CRISM data in 2008. Before then, it was thought that martian carbonate might be a sink for an ancient, denser atmosphere, but CRISMís mapping of carbonate deposits has shown that there is too little carbonate to hold more than a few millibars of carbon dioxide (about the amount present in Marsí modern atmosphere).



This CRISM image shows a site near Nili Fossae, a group of long, narrow tectonic depressions called graben. Olivine-rich igneous rocks appear red, chemically altered rocks rich in iron/magnesium-containing clay-like minerals called phyllosilicates in green, and small exposures of carbonate minerals in light yellow or white. Olivine is present in many places on Mars and demonstrates that volcanism played a primary role in forming Marsí crust. Phyllosilicates, a family of clay-like minerals, demonstrate the presence of water early in Marsí history. Carbonate minerals were first found on Mars using CRISM data in 2008. Before then, it was thought that martian carbonate might be a sink for an ancient, denser atmosphere, but CRISMís mapping of carbonate deposits has shown that there is too little carbonate to hold more than a few millibars of carbon dioxide (about the amount present in Marsí modern atmosphere).

The geology of the Nili Fossae region is dominated by the Isidis impact basin just to the east. It is shown in the global view as a light blue, low-elevation circular region. The olivine-rich unit occurs surrounding Isidis and may be either volcanic lava or olivine-rich impact melt that was splashed into this location during the formation of the Isidis basin. Phyllosilicates in the crater rim pre-date the olivine and formed before Isidis. But the carbonates sit on top of the olivine and therefore are younger. They may be a product of interaction of olivine with groundwater on ancient Mars, or may have formed in springs or lakes.

Links 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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