Revealing the Clays on Mars
Phyllosilicates have been identified in numerous outcrops on Mars in Mars Express/OMEGA and MRO/CRISM images of the highlands and may be a component of Martian TES data as well. Currently there is a lack of spectral data available on how phyllosilicates and other alteration products behave in mixtures. Our project will assist in detection, characterization and quantification of phyllosilicates, zeolites, hydrated silica and glass in the Martian surface. The laboratory experiments and spectral analyses proposed here will provide a means for detecting these minerals in altered volcanic mixtures and will provide information on the hydration character of altered volcanic material on Mars. Objectives: The objectives of this work are to develop spectral tools for identification and quantification of phyllosilicates, zeolites and hydrated silica on Mars. Investigation Summary: This project entails studying the spectral properties of a suite of mixtures of phyllosilicates, zeolites, hydrated silica, volcanic glass, and altered volcanic material. Visible/infrared reflectance, thermal emission, and Mössbauer spectroscopy will be coupled with XRD in this study. Hydration bands play a key role in spectral identification of these minerals making XRD characterization of the hydration levels of these materials essential. XRD experiments will be performed on pure minerals and mixtures in order to determine changes in the samples with changes in moisture levels. Quantitative spectral analyses will be performed on VNIR and mid-IR bands in order to develop identification parameters and detection limits for these aqueous alteration products on Mars. Single scattering albedo modeling of the spectral parameters and Gaussian modeling of the spectral bands will be performed in order to make quantitative mineral determinations on the mixtures. Expected Results: This project is expected to produce VNIR, mid-IR and Mössbauer spectral information needed for remote detection of smectites, chlorites, micas, kaolinites, serpentines, zeolites, silica and glass on Mars. The XRD data will facilitate in situ detection of these minerals using MSL/CheMin. It is well known that mixtures of fine-grained components exhibit non-linear changes in spectral properties. Understanding these effects will be essential for identifying altered components on Mars. This study will also provide information about the hydration state of potential Martian surface fines.