spectral characterization of igneous rocks in the 8 to 12 μm region variation in the spectral response of silicates in the thermal infrared tir from 8 to 12 m is the foundation for potentially important applications in the lithologic characterization of terrestrial and extraterrestrial surfaces the purpose of this study is to elucidate the crystallo chemical basis for the variation in spectral behavior in terms which may be useful in remote sensing this has led to the definition of a new parameter scfm which is defined as the ratio sio2 sio2 cao feo mgo in minerals and rocks this parameter reflects the degree of depolymerization of the silica tetrahedra and is therefore highly correlated with the structure of tir reflectance spectra of major silicate minerals in both fine and coarse grained igneous rocks it is also a good numerical descriptor of igneous rock composition thus scfm is proposed as a very useful determinant for spectral identification of igneous rocks the scfm parameter was used to assess the effect of variations in location number and width of bands in discriminating rock composition an unfortunate ambiguity exists in the use of the term band which in spectroscopy indicates a feature in a spectrum and in remote sensing signifies a specific wavelength increment or channel the latter definition is used in this paper spectra of coarse particulate mineral and solid rock samples were acquired in the laboratory a regression analysis of bands varying in width from 0 2 to 1 4 m versus scfm results in coefficients of determination correlation coefficients r2 ranging from 0 88 for two 1 2 m wide bands to 0 97 for seven 0 2 m wide bands deletion of bands in the ozone absorption region 9 4 10 2 m results in a decrease in r2 by only 0 01 stimulation of system noise by addition of 5 random counts to the bands decreases r2 by only 0 03 because spectra structure is modified by weathering alteration and texture of the samples the validity of these results is limited to fresh igneous rocks with this constraint it is concluded that accurate spectral identification of igneous rock composition is not greatly affected by bandwidth or system noise it is the overall spectral envelope rather than the fine structure in the tir which contains most of the information diagnostic of igneous rock composition this permits design of remote sensing systems with broad bands and corresponding higher signal to noise which can be traded off against the important requirement for higher spatial resolution

distribution and characteristics of adirondack class basalt as observed by mini tes in gusev crater mars and its possible volcanic source abstract we identified 104 unique rock targets belonging to the olivine rich adirondack class using mini tes data rare rocks on the west spur of the columbia hills and on the plains east of the hills also belong to this class we present evidence that adirondack class basaltic lavas may have had their origin at apollinaris tholus linear modeling of adirondack class rock spectra shows only minor variations in mineralogy and the primary phases identified are consistent with olivine basalt having an average olivine composition of fo 45 we used factor analysis and target transformation to identify variability within a single class of rocks for the first time and we find that olivine abundance varies independently of a basaltic matrix a spectral component previously attributed to downwelling radiance is proposed here to be attributable to optically thin dust on rocks which has a greater effect on mini tes spectra than previously recognized but can explain the sloping continuum observed in adirondack class rock spectra as well as the apparent distortion of an olivine absorption spectral mixing is not completely linear leading to the overestimation of sulfate and olivine fractions and the underestimation of plagioclase feldspar although linear mixing appears to successfully replicate the majority of the observed signal published tes spectra of low albedo low dust cover olivine bearing materials do not exhibit the spectral telltales of non linear behavior probably because orbital spectra represent mostly mobile regolith that has not accumulated a sufficient dust cover over 3 6 km areas

searching for the source regions of martian meteorites using mgs tes integrating martian meteorites into the global distribution of igneous materials on mars the objective of this study was to identify and map possible source regions for all 5 known martian meteorite lithologies basalt lherzolite clinopyroxenite orthopyroxenite and dunite using data from the mars global surveyor thermal emission spectrometer mgs tes we deconvolved the tes data set using laboratory spectra of 6 martian meteorites los angeles zagami alh a77005 nakhla alh 84001 and chassigny as end members along with atmospheric and surface spectra previously derived from tes data global maps 16 pixels degree of the distribution of each meteorite end member show that meteorite like compositions are not present at or above tes detectability limits over most of the planet s dust free regions however we have confidently identified local scale 100s1000s km2 concentrations of olivine and orthopyroxene bearing materials similar to alh a77005 chassigny and alh 84001 in nili fossae in and near ganges chasma in the argyre and hellas basin rims and in eos chasma nakhla like materials are identified near the detection limit throughout the eastern valles marineris region and portions of syrtis major basaltic shergottites were not detected in any spatially coherent areas at the scale of this study martian meteorite like lithologies represent only a minor portion of the dust free surface and thus are not representative of the bulk composition of the ancient crust meteorite like spectral signatures identified above tes detectability limits in more spatially restricted areas tens of km are targets of ongoing analysis

surface textures and dynamics of the 2005 lava dome at shiveluch volcano kamchatka shiveluch is one of the largest and most active andesitic volcanoes of the kuril kamchatka arc it commonly alternates between vulcanian explosive eruptions and periods of dome growth and subsequent dome collapse driven block and ash flows the volcano was in an extended period of heightened activity for most of the period 2004 2010 we examined this activity in detail using thermal infrared tir remote sensing as part of the urgent request protocol urp program of the advanced spaceborne thermal emission and reflection radiometer aster instrument and confirmed the results with ground based photography and airborne tir camera data high spatial resolution tir images were collected during both daytime and nighttime satellite overpasses prior to and following the large explosive event eruption of 27 february 2005 and the dome growth that followed during a field campaign in august 2005 a helicopter overflight designed to acquire visible and tir data of the active dome was performed this was a nadir looking low altitude overflight and the first ever of shiveluch volcano involving non russian scientists the image data revealed an active crease structure in the center of the dome with a distinctly different crescent shaped high temperature 380 c zone roughly perpendicular to the crease in order to provide a time context and estimate extrusion rates the airborne data were compared to the spaceborne aster data and long distance ground based photography of the dome acquired by our russian colleagues the presence of a crease structure and the complex thermal pattern on the surface were both unexpected discoveries that reveal the way in which exogenous dome growth was occurring at the time this highly active period at shiveluch provides a unique example to better understand silicic lava dome growth using tir data the results also demonstrate a straightforward approach for fusing ground air and spaceborne image data which could be applied to other active domes around the world

global mineral distributions on mars 1 determining the mineralogy of mars is an essential part of revealing the conditions of the surface and subsurface a deconvolution method was used to remove atmospheric components and determine surface mineralogy from thermal emission spectrometer data at 1 pixel per degree ppd minerals are grouped into categories on the basis of compositional and spectral similarity and global concentration maps are produced all binned pixels are fit well with rms errors of 0 005 in emissivity higher rms errors are attributed to short wavelength particle size effects on dust covered surfaces significant concentrations 0 10 of plagioclase high ca pyroxene sheet silicates high si glass and hematite are detected and display distributions consistent with previous studies elevated concentrations of plagioclase and high ca pyroxene are consistent with basaltic surfaces and are located in low albedo highlands regions north of 45 s significant concentrations of plagioclase and sheet silicates high si glass and low concentrations of high ca pyroxenes are consistent with andesitic surfaces and are concentrated in both southern and northern high latitude low albedo regions andesitic surfaces in the southern hemisphere have a lower spectral contrast than northern surfaces an isolated surface located in solis planum is spectrally distinct but compositionally similar to other surfaces interpreted to be andesitic in composition concentrations of olivine below the detection limit correctly identify its presence in two of three locations potassium feldspar low ca pyroxene basaltic glass olivine sulfate carbonate quartz and amphibole are not detected with confidence at 1 ppd the results presented here indicate a predominance of volcanic compositions within martian dust free surfaces

shocked plagioclase signatures in thermal emission spectrometer data of mars abstract the extensive impact cratering record on mars combined with evidence from snc meteorites suggests that a significant fraction of the surface is composed of materials subjected to variable shock pressures pressure induced structural changes in minerals during high pressure shock events alter their thermal infrared spectral emission features particularly for feldspars in a predictable fashion to understand the degree to which the distribution and magnitude of shock effects influence martian surface mineralogy we used standard spectral mineral libraries supplemented by laboratory spectra of experimentally shocked bytownite feldspar johnson j r horz f christensen p lucey p g 2002b j geophys res 107 e10 doi 10 1029 2001je001517 to deconvolve thermal emission spectrometer tes data from six relatively large 50 km impact craters on mars we used both tes orbital data and tes mosaics emission phase function sequences to study local and regional areas near the craters and compared the differences between models using single tes detector data and 3 2 detector averaged data inclusion of shocked feldspar spectra in the deconvolution models consistently improved the rms errors compared to models in which the spectra were not used and resulted in modeled shocked feldspar abundances of 15 in some regions however the magnitudes of model rms error improvements were within the noise equivalent rms errors for the tes instrument hamilton v personal communication this suggests that while shocked feldspars may be a component of the regions studied their presence cannot be conclusively demonstrated in the tes data analyzed here if the distributions of shocked feldspars suggested by the models are real the lack of spatial correlation to crater materials may reflect extensive aeolian mixing of martian regolith materials composed of variably shocked impact ejecta from both local and distant sources

x ray digital imaging petrography of lunar mare soils modal analyses of minerals and glasses it is essential that accurate modal i e volume percentages of the various mineral and glass phases in lunar soils be used for addressing and resolving the effects of space weathering upon reflectance spectra as well as for their calibration such data are also required for evaluating the resource potential of lunar minerals for use at a lunar base however these data are largely lacking particle counting information for lunar soils originally obtained to study formational processes does not provide these necessary data including the percentages of minerals locked in multi phase lithic fragments and fused soil particles such as agglutinates we have developed a technique for modal analyses sensu stricto of lunar soils using digital imaging of x ray maps obtained with an energy dispersive spectrometer mounted on an electron microprobe a suite of nine soils 90 to 150 micrometers size fraction from the apollo 11 12 15 and 17 mare sites was used for this study this is the first collection of such modal data on soils from all apollo mare sites the abundances of free mineral fragments in the mare soils are greater for immature and submature soils than for mature soils largely because of the formation of agglutinitic glass as maturity progresses in considerations of resource utilization at a lunar base the best lunar soils to use for mineral beneficiation i e most free mineral fragments have maturities near the immature submature boundary is feo approximately or 30 not the mature soils with their complications due to extensive agglutination the particle data obtained from the nine mare soils confirm the generalizations for lunar soils predicted by l a taylor and d s mckay 1992 lunar planet sci conf 23rd pp 1411 1412 abstract

estimating silicic lava vesicularity with thermal remote sensing a new technique for volcanic mapping and monitoring remote monitoring of active lava domes pro vides insights into the duration of continued lava extru sion and detection of potentially associated explosive activity on inactive flows variations in surface texture ranging from dense glass to highly vesicular pumice can be related to emplacement time volatile content and internal structure pumiceous surface textures also pro duce changes in thermal emission spectra that are clear ly distinguishable using remote sensing spectrally the textures describe a continuum consisting of two pure end members obsidian and vesicles the distinct spec tral features of obsidian are commonly muted in pu mice due to overprinting by the vesicles which mimic spectrally neutral blackbody emitters assuming that this energy combines linearly in direct proportion to the percentage of vesicles the surface vesicularity can be estimated by modeling the pumice spectrum as a lin ear combination of the glass and blackbody spectra based on this discovery a linear retrieval model using a least squares fitting approach was applied to airborne thermal infrared data of the little glass mountain and crater glass rhyolite flows at medicine lake volcano california as a case study the model produced a ve sicularity image of the flow with values from 0 to f70 which can be grouped into three broad textural classes dense obsidian finely vesicular pumice and coarsely vesicular pumice values extracted from the image compare well with those derived from sem anal ysis of collected samples as well as with previously re ported results this technique provides the means to accurately map the areal distributions of these textures resulting in significantly different values from those de rived using aerial photographs if applied to actively deforming domes this technique will provide volcano logists with an opportunity to monitor dome wide de gassing and eruptive potential in near real time in july 1999 such an effort will be possible for the first time when repetitive global multispectral thermal infrared data become available with the launch of the advanced spaceborne thermal emission and reflectance ra diometer aster instrument aboard the earth ob serving system satellite

thermal infrared emission spectroscopy of the pyroxene mineral series the thermal infrared emissivity spectra of coarse particulate samples of compositions in the pyroxene series display reststrahlen features absorptions that distinguish not only orthorhombic from monoclinic structures but also major end members within the two structural groups as well as minerals within solid solution series the exact number of reststrahlen features observed and their positions are dependent on mineral structure and cation occupancy of the m1 and m2 sites end member quadrilateral pyroxenes mg2si2o6 fe2si2o6 ca mg fe si2o6 are easily distinguished from each other and from minerals in the nonquadrilateral series nafesi2o6 na al fe si2o6 lialsi2o6 furthermore among quadrilateral pyroxenes variations in mg mg fe are linearly correlated with several band locations as are variations in ca content in high ca clinopyroxenes in both quadrilateral and nonquadrilateral compositions christiansen feature positions are also diagnostic no correlations with minor constituents of the order of 0 05 atoms per formula unit were observed the detailed spectral characteristics of pyroxenes and their variability as a function of structure and cation occupancy are presented here with determinative curves for the identification of pyroxene composition these data have important implications for the interpretation of spectral data from both laboratory and remote sensing instruments because they should permit a more detailed determination of pyroxene composition in measured unknown pure mineral and bulk compositions dominated by surface scattering i e all particulates greater than 65 m and solid samples

evidence for locally derived ultramafic intracrater materials in amazonis planitia mars 1 we studied a dark intracrater feature in amazonis planitia using visible thermal and spectral data from the mars global surveyor mgs thermal emission spectrometer tes mgs mars orbiter camera moc and 2001 mars odyssey thermal emission imaging system ody themis instruments visible and thermal data indicate that there are heterogeneities within the dark feature at meter to kilometer scales and suggest that it represents eroded terrain containing inactive ripple like bed forms possibly armored or indurated as well as loose possibly actively saltating sediment in addition part of the dark intracrater material may be covered with dust either as an optically thin few microns thick layer or as thicker discontinuous patches the thermal properties of the dark material are consistent with a mixture of sand rock and bedrock whereas the rest of the crater floor has thermal characteristics of fine 35 m particulates spectral data indicate that the crater floor is covered by a layer of dust that is spectrally and compositionally similar to the globally homogenized surface dust in other high albedo regions on mars the mineralogy of the dark materials is mafic dominated modally by pyroxene and olivine however unlike other lithologies common in low albedo regions i e surface types i and ii its derived bulk chemistry indicates that it is an ultramafic lithology with the lowest silica content detected on mars to date sheet silicates and glasses are not identified above detection limits and as such the materials do not display evidence for significant chemical weathering the geomorphology and visible distribution of the dark intracrater materials combined with the lack of an obvious source in the region outside the crater suggest they are the product of erosion of a local source

the rocks of gusev crater as viewed by the mini tes instrument 1 the miniature thermal emission spectrometer mini tes on board the mars exploration rover spirit is part of a payload designed to investigate whether a lake once existed in gusev crater mini tes has observed hundreds of rocks along the rover s traverse into the columbia hills yielding information on their distribution bulk mineralogy and the potential role of water at the site although dust in various forms produces contributions to the spectra we have established techniques for dealing with it all of the rocks encountered on the plains traverse from the lander to the base of the columbia hills share common spectral features consistent with an olivine rich basaltic rock known as adirondack class beginning at the base of the west spur of the columbia hills and across its length the rocks are spectrally distinct from the plains but can be grouped into a common type called clovis class these rocks some of which appear as in place outcrop are dominated by a component whose spectral character is consistent with unaltered basaltic glass despite evidence from other rover instruments for significant alteration the northwest flank of husband hill is covered in float rocks known as wishstone class with spectral features that can be attributed uniquely to plagioclase feldspar a phase that represents more than half of the bulk mineralogy rare exceptions are three classes of basaltic exotics found scattered across husband hill that may represent impact ejecta and or float derived from local intrusions within the hills the rare outcrops observed on husband hill display distinctive spectral characteristics the outcrop called peace shows a feature attributable to molecular bound water and the outcrop that hosts the rock called watchtower displays a dominant basaltic glass component despite evidence from the rover s payload for significant alteration of some of the rocks no unambiguous detection of crystalline phyllosilicates or other secondary silicates has been observed by mini tes the mineralogical results supplied by mini tes provide no clear evidence that a lake once existed in gusev crater

mineralogy of martian atmospheric dust inferred from thermal infrared spectra of aerosols 1 we have utilized optical constants derived from thermal infrared spectra acquired by the mariner 9 infrared interferometer spectrometer m9 iris and mars global surveyor thermal emission spectrometer mgs tes during periods of relatively high dust low water ice opacity to generate synthetic transmission and emission spectra of the atmospheric dust using libraries of transmission and emission spectra of common rock forming minerals and their alteration products we applied a linear deconvolution algorithm to the spectra to model the dust mineralogy models of the m9 iris transmission data generally are of poor quality and the mineralogical results of these fits are unlikely to be valid fits to the tes transmission spectrum and tes and iris emission spectra are of better quality and suggest that the dust mineralogy is dominated by framework silicates feldspar and or zeolite with carbonate sulfate pyroxene and olivine identified near but below generalized detection limits evidence for phyllosilicates is not robust our results combined with those from in situ measurements and other visible to infrared spectral studies suggest that framework silicates probably feldspar dominate the dust mineralogy with lesser amounts of olivine pyroxene amorphous material hematite and magnetite and that the dust largely is the product of mechanical weathering of basaltic rocks with minor chemical alteration

quantitative compositional analysis using thermal emission spectroscopy application to igneous and metamorphic rocks the mineral composition of a suite of igneous and metamorphic rocks was determined using the thermal infrared emission spectra of these rocks in a linear spectral deconvolution algorithm this algorithm assumes that the infrared spectrum of each rock is a linear mixture of the component mineral spectra weighted by volume abundance a diverse suite of 36 common rock forming and accessory minerals was used in the deconvolution the model was tested by comparing the mineralogy derived from the infrared spectrum with petrographically estimated abundances for 45 igneous and 51 metamorphic rock samples the mineral abundances derived from these two techniques agree to within 67 15 for the primary minerals feldspar pyroxene quartz and calcite dolomite and 69 17 for secondary minerals such as micas and amphiboles these differences are comparable to the error for traditional thin section mode estimates which are 65 15 for major minerals and 5 for minor minerals the detection limit for the primary and secondary minerals found in the rocks analyzed ranged from 5 to 10 each major rock type studied here was easily distinguished by its spectral characteristics the best results in both the qualitative determination of the rock type and dominant minerals and the quantitative reproduction of absorption features and mineral composition were obtained for igneous rock samples for metamorphic rocks pelite and quartzo feldspathic samples gave slightly better results than calcareous or mafic samples a controlled analysis in which the end member suite was reduced based on an initial estimate of the rock type only improved the results by several percent for most primary and secondary minerals the quality of the obtained results demonstrates that a linear deconvolution of infrared emission spectra provides an accurate rapid technique for determining the quantitative mineral composition of rock samples in a laboratory and has application to future in situ measurements

quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy 2 application to compacted fine grained mineral mixtures and assessment of applicability of partial least squares methods fine grained sedimentary deposits on planetary surfaces require quantitative assessment of mineral abundances in order to better understand the environments in which they formed one way that planetary surface mineralogy is commonly assessed is through thermal emission 6 50 m spectroscopy to that end we characterized the tir spectral properties of compacted very fine grained mineral mixtures of oligoclase augite calcite montmorillonite and gypsum non negative linear least squares minimization nnls is used to assess the linearity of spectral combination a partial least squares pls method is also applied to emission spectra of fine grained synthetic mixtures and natural mudstones to assess its applicability to fine grained rocks the nnls modeled abundances for all five minerals investigated are within 10 of the known abundances for 39 of the mixtures showing the relationships between known and modeled abundance follow non linear curves the poor performance of nnls is due to photon transmission through small grains over portions of the wavelength range and multiple reflections in the volume the pls method was able to accurately recover the known abundances to within 10 for 78 90 of synthetic mixtures and for 85 of the mudstone samples chosen for this study the excellent agreement between known and modeled abundances is likely due to high absorption coefficients over portions of the thermal infrared tir spectral range and thus combinations are linear over portions of the range pls can be used to recover abundances from very fine grained rocks from tir measurements and could potentially be applied to landed or orbital tir observations

subparallel dipping faults that ruptured during the 2008 wenchuan earthquake abstract we investigated the kinematic rupture along a complicated fault system during the 2008 wenchuan earthquake assuming a slip distribution estimated using interferometric synthetic aperture radar insar data by hao et al 2009 we tried to fit two near fault station seismograms one of which was located between two subparallel dipping faults forward numerical simulation results suggest that two subparallel dipping faults ruptured coseismically during the 2008 wenchuan earthquake this result provides a constraint on the dynamic fault interaction of reverse fault earthquake which is different from the branched strike slip faults where the free surface does not affect the rupture branching

mineralogical composition of sands in meridiani planum determined from mars exploration rover data and comparison to orbital measurements constraints on the mineralogical composition of low albedo low sulfur sands at meridiani planum are determined from mars exploration rover mer opportunity miniature thermal emission spectrometer mini tes mossbauer and alpha proton x ray spectrometer measurements results of this work show that the sand is olivine basaltic in composition with minor amounts of sulfate and a high silica phase glass or secondary amorphous silica measurements from all three instruments indicate that pyroxene is twice as abundant as olivine and that the pyroxene composition is dominated by the low calcium variety the volume abundance of olivine is constrained to be 10 15 results from detailed analyses of mer data are used to ground truth the spectral emissivity and mineral abundances derived from orbit with mars global surveyor tes data tes derived mineral abundances are within 5 of those derived from mer data which is generally within the statistical errors associated with tes derived phase abundances the agreement lends support to global and regional scale variations in mineralogical composition determined from tes data in previous studies an alternative method of least squares minimization is used for modeling the tes and mini tes data the benefits of this method are demonstrated by comparison with conventional least squares techniques previously used by tes data users

mineralogy at meridiani planum from the mini tes experiment on the opportunity rover the miniature thermal emission spectrometer mini tes on opportunity investigated the mineral abundances and compositions of outcrops rocks and soils at meridiani planum coarse crystalline hematite and olivine rich basaltic sands were observed as predicted from orbital tes spectroscopy outcrops of aqueous origin are composed of 15 to 35 by volume magnesium and calcium sulfates a high silica component modeled as a combination of glass feldspar and sheet silicates 20 to 30 and hematite only minor jarosite is identified in mini tes spectra mini tes spectra show only a hematite signature in the millimeter sized spherules basaltic materials have more plagioclase than pyroxene contain olivine and are similar in inferred mineral composition to basalt mapped from orbit bounce rock is dominated by clinopyroxene and is close in inferred mineral composition to the basaltic martian meteorites bright wind streak material matches global dust waterlain rocks covered by unaltered basaltic sands suggest a change from an aqueous environment to one dominated by physical weathering

microlites and nanolites in rhyolitic glass microstructural and chemical characterization we used transmission electron microscopy tem and scanning electron microscopy sem to study magmatic crystals in the ben lomond rhyolite lava dome taupo volcanic center new zealand using tem and sem to investigate the size distributions of these crystals we identified three size populations microphenocrysts 1 2 m wide microlites 0 6 m wide and smaller crystals 0 6 m wide which we term nanolites the predominant mineral phases of the microlites and nanolites are augites pigeonites and hypersthenes the compositions and microstructures within these pyroxenes indicate disequilibrium crystallization at approximately 850 900 c and undercoolings as high as 300 c from equilibrium crystallization temperatures complex microstructures resulting from subsolidus reactions in augite and pigeonite are consistent with moderate cooling rates within the upper obsidian layer of the ben lomond rhyolite dome this study demonstrates the existence of sub micron magmatic crystals in a rhyolite and illustrates the potential of tem to provide unique information about the crystallization and cooling histories of glassy volcanic rocks

determination of martian meteorite lithologies and mineralogies using vibrational spectroscopy we have acquired thermal infrared emission spectra of four martian meteorite samples alh77005 nakhla zagami and eet79001 representing three major lithologies iherzolite clinopyroxenite and basalt the spectra of these meteorites are significantly different from each other and we can distinguish the three lithologies easily on the basis of their spectral morphologies using a linear deconvolution model the modal mineralogies of alh77005 nakhla and zagami were derived from their spectra to within 2 19 of the modes derived by optical methods for zagami and eet79001 the correct mineral types were identified as present using the linear method although an exact spectral match using available end member spectra was not obtained probably due to the lack of a pigeonite end member spectrum or shock effects in the meteorites the meteorite spectra we have acquired will be used for comparison with data to be returned by the thermal emission spectrometer tes on the mars global surveyor orbiter and would also be useful for comparing to future rover or lander based thermal ir spectra based on our results comparisons of mineral end member and meteorite spectra with tes spectra of coarse regolith and rocky regions should aid identification and mapping of martian surface lithologies and unit mineralogy

a large spectral survey of small lunar craters implications for the composition of the lunar mantle a global spectral survey of 4506 immature craters with diameters 1 km was carried out using near ir data from the kaguya spectral profiler to characterize the composition of the lunar megaregolith on the basis of band minima and radiative transfer mixing models small crater spectra fall into three groups 1 mare basalts with strong absorptions at relatively long wavelengths indicating high ratios of high to low ca pyroxene 2 norites containing about 50 plagioclase and with pyroxene assemblages dominated by low ca pyroxene that occur within the south pole aitken basin spa near apollo 14 and other locations near imbrium basin and three major cryptomaria deposits and 3 noritic anorthosites occurring within the feldspathic highlands terrane containing about 20 wt pyroxene with a pyroxene assemblage containing exclusively very low ca pyroxene very few pure anorthosites are present in this survey and there are no occurrences of pyroxene poor olivine rich assemblages models of the composition of basin ejecta incorporate large amounts of mantle material and the spectral results require that that the sampled mantle is orthopyroxenite basin depth diameter ratios used in the models required to match the measured composition are consistent with prior estimates for the largest basins the composition found in the spa and imbrium regions are consistent with mafic impact melt breccias or basaltic impact melts of basin origin for spa we model this composition and find it requires an extremely low impact angle while this is consistent with prior work on an oblique impact for the spa event a more robust solution invokes the production of norite in impact melt seas

determining the modal mineralogy of mafic and ultramafic igneous rocks using thermal emission spectroscopy the modal mineralogies of 20 mafic and ultramafic igneous rocks were determined from their thermal infrared emission spectra using a linear deconvolution approach which uses a library of end member mineral spectra to model a bulk rock spectrum over 90 of the modes obtained from thermal emission spectra agree with modes obtained by traditional optical analyses to within the stated error of the optical analyses 5 15 vol library spectra of several compositions within a solid solution series e g plagioclase feldspars labradorite and bytownite were commonly used in each best fit model and are assumed to represent in combination a composition in the rock for which an identical mineral spectrum was unavailable in the library the accuracy of this assumption was evaluated by calculating a weighted average solid solution composition for plagioclase and or pyroxenes from the library minerals used in the model best fit of 14 rocks and comparing these compositions to the actual chemistries measured by electron microprobe or the optically estimated an the derived solid solution compositions are generally within 10 15 an or mg of the measured composition modal data derived from the spectra via the deconvolution were summed and converted to weight percent wt oxides for comparison to standard bulk chemistry data sio2 al2o3 and na2o k2o were generally slightly overestimated and feo and mgo were typically slightly underestimated modes and wt oxides were plotted on standard rock type classification diagrams and provide broadly accurate classifications demonstrating that the linear deconvolution technique is successful at deriving useful mineralogical information from thermal infrared emission spectra of bulk rock samples furthermore convolution of the laboratory data to spectral resolutions comparable to remote sensing instruments specifically the mars global surveyor thermal emission spectrometer demonstrates only a 5 vol increase in modal uncertainty for minerals present in abundances 10 vol this study thus provides a strong foundation for the application of this technique to mafic igneous sample spectra from both laboratory and remote sensing instruments

a study of low albedo deposits within amazonis planitia craters evidence for locally derived ultramafic to mafic materials 1 we studied low albedo deposits in the floors of craters within the amazonis planitia region using infrared data from mars global surveyor thermal emission spectrometer tes and mars odyssey thermal emission imaging system themis high resolution visible images from the mars orbiter camera and themis and topographic data from the mars orbiter laser altimeter these deposits are found within subdued to sharp rimmed craters that impacted into thick basaltic lava flows from olympus mons these lava flows flooded the region and were subsequently eroded by aeolian processes tes spectral modeling of the low albedo deposits reveals a mineralogy that is dominated by mafic minerals olivine pyroxene with a derived bulk chemistry that ranges from ultramafic to mafic 40 52 wt sio2 in composition these bulk compositions are comparable to some martian lithologies but represent some of the lowest silica contents identified on mars the compositional range could be produced by either primary igneous processes or subsequent alteration by aeolian processes the spatial distribution of the compositions reveals weak to absent groupings and does not distinguish between the igneous or aeolian scenarios in some craters possible local sources have been identified within the crater walls floors and interiors local sources may be present in additional craters but obscured by dust no regional sources were identified within a reasonable distance in terms of sand transport but may also be obscured by dust therefore the low albedo deposits probably resulted from aeolian erosion of local intracrater basaltic materials that were subsequently redistributed within the floors of these craters

upper mantle structure of the baltic shield below the swedish national seismological network snsn resolved by teleseismic tomography summary upper mantle structure under the baltic shield is studied using non linear high resolution teleseismic p phase tomography observed relative arrival time residuals from 52 teleseismic earthquakes recorded by the swedish national seismological network snsn are inverted to delineate the structure of the upper mantle the network consists of 47 currently working three component broad band stations located in an area about 450 km wide and 1450 km long in order to reduce complications due to possible significant three dimensionality of earth structure events chosen for this study lay close to in line with the long axis of the array 30 results indicate p wave velocity perturbations of 3 per cent down to at least 470 km below the network the size of the array allows inversion for structures even at greater depths and lateral variations of velocity at depths of up to 680 km appear to be resolved below the central part of the array 60 64 n where ray coverage is best the data reveals a large region of relatively low velocity at depths of over about 300 km at depths less than about 250 300 km the models include a number of features including an apparent slab like structure dipping gently towards the north