EXTENDING SURFACE COMPOSITIONAL MAPPING ON MARS USING CRISM MAPPING DATA

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) [1] measures the composition of Mars’s surface and provides insight into the ancient climate record that records the presence of water on the planet. We will present ongoing mapping using CRISM ~180-m/pixel mapping-mode data and validation of generated 5x5 degree tiles of three unique areas on Mars’s southern hemisphere: 1) Terra Sabaea, which lies to the northwest of Hellas Basin, 2) Northwest Noachis, south of Valles Marineris, and 3) Central Valles Marineris. Spectral absorptions extracted from regions of interest in each area are compared with spectra from reference CRISM and laboratory spectra [2] in order to identify and classify dominant spectral components. Our current findings from mapping in Terra Sabaea are consistent with the mineralogy that has previously been identified in the greater Hellas region [3,4]. The phases mapped primarily include low and high calcium pyroxenes as well as olivine along the rims of impact craters and intercrater plains. In Northwest Noachis, the presence of low- and high-calcium pyroxene and magnesium smectite indicate a potentially aqueous history as phyllosilicates are commonly formed through aqueous alteration [5,6]. In Valles Marineris, the strong spectral signatures of monohydrated and polyhydrated sulfates on the valley floor reveal an alternating pattern consistent with previous observations [7,8]. By extending our ~180-m/pixel mapping to the surrounding area on the valley floor, we anticipate being able to confirm and expand on previous investigations using targeted ~18-m/pixel CRISM data. These three regions represent a rich history of diverse and complex surface environments, and their detailed regional mapping allows us to interpret and understand past climate, mineralogic, and geological processes on Mars.

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