Detection and Mapping of Hydrated Mineral Phases associated with Flat-Floored Noachian Impact Craters in the Southern Highlands on Mars

The oldest surfaces on Mars date to the Noachian era, defined by its comparatively high abundance of large impact craters. Within these craters is a record of the processes that have occurred since their formation, thereby resulting in them being filled in with sediment or capped by volcanic rock. By utilizing the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO), we are investigating the mineralogical composition of wind-eroded floor materials present within, and surrounding, 30 Noachian-aged impact craters, which span three geographic regions that collectively make up our study region. Here, we pay particular attention to the exposed hydrated mineral phases associated with this subset of flat-floored craters. We also focus on the presence of feldspathic material in association with the aforementioned hydrated materials within the defined region of study, specifically in the Noachis Terra region (Carter and Poulet, 2013 and Wray et al., 2013). These phases are present within layered deposits consisting of infill and observable crater wall stratigraphy, in uplifted materials associated with central peaks, in ejecta from smaller superposed craters that sample the underlying stratified infill, and in materials on the plains surrounding the craters themselves. Our approach involves comparing ratioed CRISM spectra to the USGS spectral library (Clark et al., 2007) in order to identify the hydrated minerals present within our region of study. This will help further our knowledge of the past aqueous alteration environments of the southern highlands and possibly add to the wide array of hydrated mineral phases already reported on in this region by Mustard et al. (2008), Murchie et al. (2009), Wray et al. (2009), and others. Specifically, we have observed feldspathic material intermixed with Mg-, Fe-, and Al-smectite (spectrally confirmed) along with other stand-alone hydrated materials (sans feldspathic material) that include hydrated silica (i.e., opal) and possibly other less common phyllosilicates (i.e., kaolinite, illite, and other Al-clays). These results will be presented using maps created through the utilization of ArcGIS with the presence of these mineral phases being confirmed via the method highlighted above and demarcated accordingly.