Characterizing Mafic, Clay, and Carbonate Components found in MRO/CRISM Images in Libya Montes, Mars, using Advances in Automated Gaussian Modeling of Spectral Features

Aqueous processes have been inferred at the Libya Montes rim/terrace complex of the southern Isidis Basin due to the dense concentration of valley networks [1]. Coordinated CRISM-HiRISE investigations of this region characterized discrete units of ancient phyllosilicate deposits covered by an olivine-rich material and a pyroxene caprock [2]. CRISM mapping data show minor phyllosilicate abundances widespread throughout the Southern Highlands [3], which are dominated by low-Ca pyroxene bearing material [4,5]. The carbonate magnesite has also been located throughout this area [6] and at Libya Montes [7]. Our current study involves detailed characterization of the minerals present at Libya Montes through implementation of improved automated Gaussian modeling methods. We have developed an automated procedure for modeling spectral features using Gaussians that has been successfully applied to laboratory studies and hyperspectral analyses of Mars [8,9,10,11]. Several studies are being conducted to improve and validate these models. These include a comparison of initialization methods, continuum methods, optimization algorithms, and modeled functions. The modeled functions compared include Gaussians, saturated Gaussians, and Lorentzians. This algorithm and the modeling studies are currently being applied towards analyses of CRISM hyperspectral images of Libya Montes and laboratory spectra of mineral mixtures. Specifically, olivine, pyroxene, phyllosilicate, and carbonate deposits are being modeled and classified by composition in CRISM images. References [1]Crumpler, L. S., and K. L. Tanaka (2003) J. Geophys. Res., 108, DOI: 8010.1029/2002JE002040. [2]Bishop, J. L., et al. (2007) 7th Int'l Mars Conf. [3]Mustard, J. F., et al. (2008) Nature, 454, 07305. [4]Bibring, J.-P., et al. (2005) Science, 307,1576. [5]Mustard, J. F., et al.(2005) Science, 307, 1594. [6]Ehlmann, B. L., et al. (2008) Science, 322, 1828. [7]Perry, K., et al. (2009) AGU Fall Mtng. [8]Makarewicz, H. D., et al. (2009) IEEE Whispers Wkshp. [9]Makarewicz, H. D., et al. (2008) AGU Fall Mtng. [10]Makarewicz, H. D., et al. (2009) LPSC. [11]Makarewicz, H. D., et al. (2009) Lunar Sci Forum.