| Dr. Janice Bishop - Principal Investigator
Projects
Formation of Magnetic Minerals on Mars by Alteration of Nanophase Ferric Oxides/Oxyhydroxides
NNX06AB23G
The magnetic experiments on the Viking and Pathfinder missions are consistent with the presence of a few wt.% Fe2O3 as tiny maghemite and/or magnetite grains imbedded in the 2-3 micron-sized dust/soil particles. An explanation is lacking for how these magnetic minerals formed on Mars. The experiments described here will provide data needed to understand this process and identify the magnetic phases in the fine-grained martian surface material. Objectives: The objectives of this work include developing plausible formation mechanisms for the magnetic minerals/phases on Mars and developing techniques for identifying them there. Investigation Summary: We propose to perform reduction/oxidation experiments on nanophase ferric oxides/oxyhydroxides in order to define possible pathways for magnetite and maghemite formation and alteration in the martian soil. This project will include synthesis and characterization of the initial ferrihydrite, lepidocrocite, goethite, hematite, magnetite and maghemite samples and their alteration products with visible/near-infrared (VNIR), mid-IR, and Mossbauer spectroscopies, magnetic properties, high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). Alteration of the nanophase ferric oxides/oxyhydroxides will be performed at low temperatures initially using a differential thermal analyzer (DTA) and subsequently a vacuum heating system developed for these experiments. We will also produce spectral parameters for detection of these minerals on Mars using VNIR, mid-IR and Mossbauer spectroscopy from the recent, current and upcoming missions. Expected Results: This study seeks to identify formation mechanisms and stability parameters for magnetic minerals in the martian dust/soil component through lab alteration studies of iron oxides/oxyhydroxides. We will establish quantitative methods for identifying magnetite and maghemite in the fine-grained surface material on Mars.
Searching for Aqueous Activity on Mars Through Analyses of VNIR Spectral Images
NNX06AD88G
Revealing the Clays on Mars
NNX08AZ05G
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, kaoliniteserpentines,
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.
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