Mixtures of Sulfates in Melas Chasma
Mixtures of Sulfates in Melas Chasma
ESP_051129_1705  Science Theme: Sedimentary/Layering Processes
Many locations on Mars have sulfates, which are sedimentary rocks formed in water. Within Valles Marineris, the large canyon system that cuts across the planet, there are big and thick sequences of sulfates.

In this image, layering within the light-toned sulfate deposit is the result of different states of hydration. Some of the layers have sulfates with little water (known as monohydrated sulfates) whereas other layers have higher amounts of water (called polyhydrated sulfates). The different amounts of water within the sulfates may reflect changes in the water chemistry during deposition of the sulfates or may have occurred after the sulfates were laid down when heat or pressure forced the water out of some layers, causing a decrease in the hydration state.

The CRISM instrument on MRO is crucial for telling scientists which type of sulfate is associated with each layer, because each hydration state will produce a spectrum with absorptions at specific wavelengths depending upon the amount of water contained within the sulfate.

Written by: Cathy Weitz (narration: Tre Gibbs)  (4 September 2017)
Acquisition date
23 June 2017

Local Mars time

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Spacecraft altitude
261.9 km (162.7 miles)

Original image scale range
26.4 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

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25 cm/pixel and North is up

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42°, with the Sun about 48° above the horizon

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23.6°, Northern Spring

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Sub-solar azimuth:  32.1°
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NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.