A MARRIAGE MADE ON MARS: USING HIRISE AND CRISM DATA SETS TO STUDY LIGHT-TONED HYDRATED DEPOSITS IN AND AROUND VALLES MARINERIS (Invited Presentation)

The Mars Reconnaissance Orbiter spacecraft carries the High Resolution Imaging Science Experiment (HiRISE) and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). One type of deposit on Mars where high resolution imaging of morphology combined with spectral detection of hydrated minerals has been extremely important for analyses are the light-toned hydrated deposits in and around Valles Marineris.

Noctis Labyrinthus has perhaps the most diverse assemblages of hydrated minerals on Mars that are associated with light-toned deposits both within the depressions and along the adjacent plateau. Thus far, the following minerals have been identified: several kinds of sulfates (monohydrated (kieserite, szomolnokite) and polyhydrated sulfates, jarosite, and Ca-sulfates (gypsum, bassanite)), clay minerals (Fe/Mg-smectites and Al-phyllosilicates), a doublet absorption between 2.2-2.3 µm due to an unusual alteration phase, and hydrated silica/opal.

The chasmata of Valles Marineris also host a diverse range of light-toned hydrated deposits, most of which are composed of either monohydrated or polyhydrated Mg-bearing sulfates. Other minerals associated with smaller deposits inside the chasmata include clays, jarosite, Ca-sulfates, and the 2.2-2.3 µm doublet material. HiRISE stereo-derived Digital Terrain Models (DTMs) have been used to see the drapping nature of the doublet materials on wall rock outcrops, supporting an airfall origin for this material. Another synergistic analysis of HiRISE and CRISM data was performed at fresh exposures of hydrous Fe-bearing amorphous silica exhibiting strong hydration features and found along the wall rock slopes of Coprates Chasma. Coprates catena has terraced fans and light-toned deposits that contain a range of minerals.

Several of the plateaus outside Valles Marineris have sinuous ridges composed of light-toned layered deposits that could be inverted channels. CRISM spectra show the presence of a unique FeSO₄OH phase not stable on Earth in association with the Juventae plateau deposits. Understanding these diverse deposits is critical for deciphering the climate and aqueous history of Mars.