Mineral composition of the Martian Gale and Nili Fossae regions from Mars Reconnaissance Orbiter CRISM images

摘要

The identification and classification of minerals on the Martian surface can provide important information and constraints on the environmental and geological evolution. In-situ observations by the Martian Curiosity rover at the landing site in the Gale region provided evidence of water molecules, sulfur, and chlorine, as well as hydrous phyllosilicates. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) has enhanced spectral resolution and can provide information across much greater spatial and time scales. In this paper, CRISM near-infrared spectral data are used to identify mineral classes and their distributions in the Martian Gale and Nili Fossae regions. Using multiple spectral parameter analysis for the Gale Crater region, the distributions of important mineral classes have been mapped, including mafic minerals, hydrated minerals, and carbonates. Using the diagnostic absorption feature from 1.0 to 2.6 μm, six hydrous mineral species are mapped in the Nili Fossae region, including kaolinite, nontronite, chlorite, and vermiculite, which are mostly formed by the weathering or hydrothermal alteration. Specifically, the formation of nontronite needs moderate pH and reducing conditions, which are favorable for the preservation of organic materials. The detection of these minerals in the Nili fossae region suggests that the region has experienced long-term weathering and hydrothermal effects.