[1] We used spectral indexing and linear deconvolution to compare thermal infrared emission spectra of Fo 91 , Fo 68 , Fo 53 , Fo 39 , Fo 18 , and Fo 1 olivine samples to Mars Global Surveyor Thermal Emission Spectrometer (TES) data over low-albedo regions of Mars. The Fo 91 , Fo 68 , Fo 53 , and Fo 39 spectral end-members were confidently identified on Mars, a range of compositions wider than inferred from Martian meteorites. Small (less than hundreds of square kilometers) occurrences of the Fo 91 spectral end-member are present in the rims of the Argyre and Hellas impact basins and may represent Martian mantle materials. The Fo 68 spectral end-member is common throughout the highlands, chasmata, outflow channels, and Nili Fossae region. The Fo 53 spectral end-member occurs in eastern Syrtis Major, the Nili Fossae region, and smooth-floored craters of the highlands. Although less abundant than Fo 68 and Fo 53 , the distribution of the Fo 39 spectral endmember suggests that some olivine on Mars is more Fe-rich than olivine in Martian meteorites. Global maps of olivine show that (1) materials containing 10-20% of olivine are common in the southern highlands of Mars, (2) olivine is most common near the topographic dichotomy boundary, and (3) olivine becomes uncommon near the poles suggesting that it may be influenced by topography and/or latitude (climate). Olivine is found in early Noachian to Amazonian terrains, some of which may be coeval with phyllosilicate and sulfate deposits detected by OMEGA implying that any early Noachian wet period of Mars' climate history may have been globally inhomogeneous or insufficient to weather the olivine that remains today.Citation: Koeppen, W. C., and V. E. Hamilton (2008), Global distribution, composition, and abundance of olivine on the surface of Mars from thermal infrared data,

[1] Hematite-bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a partially eroded layered complex that covers dissected Noachian-aged cratered terrain. The hematite unit consists of dark plains and dunes covering a bright substrate. This substrate is fully exposed beyond the borders of the hematite-bearing deposit and consists of polygonal ground separated by ridges or valleys, together with layered deposits that have been eroded into a variety of landforms. The complex is partially covered by a regional-scale aeolian mantle that thickens toward the north. The hematite-bearing stratum exhibits low albedoes, pulse widths, and intermediate thermal inertias, whereas the underlying unit exhibits high values of these parameters. Both units have spectral emissivity signatures similar to those for the low albedo cratered terrain to the south, with the addition of hematite for the top stratum. The complex is interpreted to consist of extensive plains-forming lava flows and tephra deposits emplaced during an extensional regime and at least partially buried by an aeolian mantle. Aeolian stripping of the mantle exposed much of the complex and differentially eroded the deposits to produce the landforms existent today. Exploration of the hematite-bearing deposits by the 2003 Mars Exploration Rover, ''Opportunity,'' will allow testing of the hypotheses presented since this stratum has been locally reworked into dunes that only partially cover the underlying brighter portion of the complex. In particular, the rover-based measurements will allow us to test the extent to which the unusual remote-sensing properties of the units indicate aqueous alteration.

We developed and tested an automated algorithm that analyzes thermal infrared satellite time series data to detect and quantify the excess energy radiated from thermal anomalies such as active volcanoes. Our algorithm enhances the previously developed MODVOLC approach, a simple point operation, by adding a more complex time series component based on the methods of the Robust Satellite Techniques (RST) algorithm. Using test sites at Anatahan and Kīlauea volcanoes, the hybrid time series approach detected~15% more thermal anomalies than MODVOLC with very few, if any, known false detections. We also tested gas flares in the Cantarell oil field in the Gulf of Mexico as an end-member scenario representing very persistent thermal anomalies. At Cantarell, the hybrid algorithm showed only a slight improvement, but it did identify flares that were undetected by MODVOLC. We estimate that at least 80 MODIS images for each calendar month are required to create good reference images necessary for the time series analysis of the hybrid algorithm. The improved performance of the new algorithm over MODVOLC will result in the detection of low temperature thermal anomalies that will be useful in improving our ability to document Earth's volcanic eruptions, as well as detecting low temperature thermal precursors to larger eruptions.

1] Thermal infrared spectra of glasses and phyllosilicates have similar shapes leading to a proposed ambiguity in deconvolution results. We quantify the spectral separability of these two classes using discriminant analysis and linear deconvolution. We apply the deconvolution technique to single spectra, and two-and four-component mixtures. Missing end-members result in quantifiable uncertainties between modeled abundances of glasses and phyllosilicates. Mixtures containing silica-K 2 O glass are susceptible to overestimating phyllosilicates with minimal increases in root-mean-square error if the silica-K 2 O glass spectrum is not present in the end-member set. Missing phyllosilicate end-members are likely to be modeled as combinations of other phyllosilicates rather than glasses, with saponite, nontronite, and halloysite showing the highest uncertainties. Empirically, ±15% of the total glass plus phyllosilicate abundance incorporates all uncertainties in derived glass abundance if the glass in the mixture is in the end-member set. If the glass in the mixture is excluded from the end-member set, these uncertainties increase to ±65%. Four-component mixtures show that glasses and phyllosilicates act as a two-component mixing system but can induce small uncertainties in other components. Applying the maximum derived uncertainties to deconvolutions of surface type 2, measured by the Mars Global Surveyor Thermal Emission Spectrometer, we find that silica-K 2 O glass abundance is above the instrument detection limit and a likely component of the surface. Pure silica glass, a proposed amorphous weathering product, is the least likely candidate for confusion with phyllosilicates and its noninclusion in models of Martian spectra suggests it likely is not a component of the Martian surface.Citation: Koeppen, W. C., and V. E. Hamilton (2005), Discrimination of glass and phyllosilicate minerals in thermal infrared data,

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