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Hydroxylated Ferric Sulfates in Aram Chaos
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Hydroxylated Ferric Sulfates in Aram Chaos

Acquired Date: January 20, 2008
Release Date: November 8, 2013
Latitude: 3.92 N
Longitude: -20.48 E
Keywords: Chaos/Chasmata, Hydrated Mineral, Layered Mineral, Sulfate minerals, Northern Lowlands, Valles Marineris
Parameters: BD1900R/BD1950 (H2O), BD2100_2 (Monohydrated sulfates), SINDEX2 (Hydrated mineral)

Aram Chaos is a circular area of chaos terrain located at the eastern end of the Valles Marineris canyon system. An incredibly diverse array of sulfate minerals occur here. This image shows two major classes of sulfates, distinguished by the amount of water bound into the sulfates’ crystal structures. Monohydrated sulfates (with one water molecule per sulfate molecule) are shown in yellow, and polyhydrated sulfates (with multiple waters per sulfate molecule) are shown in magenta. Also found at this location is hydroxylated ferric sulfate, a compound containing oxygen, hydrogen, sulfur and iron but lacking in bound molecular water.



Aram Chaos is a circular area of chaos terrain located at the eastern end of the Valles Marineris canyon system. An incredibly diverse array of sulfate minerals occur here. This image shows two major classes of sulfates, distinguished by the amount of water bound into the sulfates’ crystal structures. Monohydrated sulfates (with one water molecule per sulfate molecule) are shown in yellow, and polyhydrated sulfates (with multiple waters per sulfate molecule) are shown in magenta. Also found at this location is hydroxylated ferric sulfate, a compound containing oxygen, hydrogen, sulfur and iron but lacking in bound molecular water.

The different kinds of sulfates on Mars are thought to record different environmental conditions, with polyhydrated sulfates requiring a wetter environment than monohydrated sulfates. Hydroxylated ferric sulfates record the dryest environment of all – so dry, in fact, that no place on Earth is dry enough for this material to occur naturally. On Earth, it exists in factories and chemistry labs only. Because is not naturally occurring on Earth, it does not meet the textbook definition of a mineral.

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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