lithological mapping of central part of mare moscoviense using chandrayaan 1 hyperspectral imager hysi data abstract we conducted spectral analysis of central region of the mare moscoviense area on the far side of the moon using the hyperspectral imager hysi data from the chandrayaan 1 mission in an effort to identify and map the major lithological units present in the area various spectral band parameters namely band curvature band tilt and band strength have been used for lithological discrimination based on the nature of the spectral profile these band parameters essentially measure the shape position and strength of the absorption feature near 1000 nm arising due to electronic transition of fe 2 in crystallographic sites of major rock forming silicates spectral band parameters have been used for generating rock type composite image based on spectral studies and rock type composite image as obtained using band parameters five major compositional units have been identified highland basin soils ancient mature mare highland contaminated mare buried unit with abundant low ca pyroxene lcp and youngest mare unit in the present study a multispectral approach in the form of spectral band parameters has been adopted for analysing the hysi hyperspectral data from chandrayaan 1 mission present study clearly shows that the spectral band parameters obtained using selected hysi channels could efficiently be used to discriminate and delineate the major litho units present across the central part of mare moscoviense and the same approach can thus be used for lithological mapping of other parts of lunar surface using hysi data

age profiles in elephant and mammoth bone assemblages abstract age profiles of modern african elephant loxodonta africana populations are significantly affected by drought conditions that cause local die offs subadult animals die in proportions that may be nearly twice what is recorded in live populations such biasing of death sample age profiles might also have occurred during late pleistocene die offs of mammuthus this comparative study of modern and fossil proboscidean age structures supports a tentative interpretation that late pleistocene extinction of mammuthus at least in the southwestern united states resulted from severe drought conditions at which clovis hunters were witnesses but not necessarily frequent participants

metal silicate mixtures spectral properties and applications to asteroid taxonomy the reflectance spectra of combinations of olivine orthopyroxene and iron meteorite metal show systematic variations in spectral properties which can be used to constrain many of the physical and chemical properties of the assemblages the presence of metal most noticeably affects band area ratios peak peak and peak minimum reflectance ratios and band widths these parameters are also affected to varying degrees by the abundance and grain size of the metal and silicates and the composition of the silicates band width and band areas are useful for determining metal abundance in olivine metal and orthopyroxene metal assemblages respectively mafic silicate grain size variations are best determined using band depth criteria band centers are most useful for determining mafic silicate composition analysis of the reflectance spectrum of the s class asteroid 8 flora on the basis of these spectral parameters indicates a surface composed of approximately 50 wt metal 40 wt olivine fa 35 10 10 wt orthopyroxene fs 30 25 35 and perhaps a few weight percent of clinopyroxene a substantial amount of the surface seems to consist of a fine grained 45 m size component analysis of the reflectance spectrum of the a class asteroid 446 aeternitas suggests a surface assemblage of approximately 35 wt metal 55 wt olivine fa 20 10 7 wt clinopyroxene fs 17 and 3 wt orthopyroxene fs 45 a substantial fine grained 45 m size surface component is also indicated for this asteroid

low temperature aqueous alteration of basalt mineral assemblages of deccan basalts and implications for mars spectra of basalt samples were dominated by fe 2 crystal field transitions with weak alteration bands near 1 4 and or 1 9 mm reststrahlen bands in mid infrared showed the convolution of plagioclase and pyroxene features typical of basalts saprolite samples were incompletely leached and their spectra were dominated by complex al and fe mg bearing smectite clays and retained no original mafic signatures xrd and mossbauer detected pyroxene and plagioclase not visible by reflectance spectroscopy in some saprolite samples zeolites were present throughout the saprolite the laterite was the most leached horizon and all analyses showed kaolinite and iron oxide assemblages this kaolinite and hematite association would be expected if kaolinite on mars formed through leaching under conditions similar to those on earth and has implications for abundant freshwater on the martian surface

the influence of closed brine pockets and permeable brine channels on the thermo elastic properties of saline ice a model of the thermo elastic behaviour of saline ice is formulated and model solutions describing thermo elastic waves tew propagating into a half space of the ice are investigated the model is based on a proposal that saline ice is a matrix which encompasses both closed brine pockets and permeable channels filled with brine experiments on the thermal expansion of saline ice samples and on tew in saline ice have been performed in the cold laboratories of the university centre in svalbard and in university college london the experimental data are compared with theoretical conclusions the experimental data support our hypothesis that the brine in saline ice is divided between closed pockets and open permeable channels this article is part of the themed issue microdynamics of ice

thermo mechanical loads of confined sea ice on structures records of the ice pressures on the joggle skirt of the coal quay in spitsbergen were performed over winter seasons in 2013 and 2015 the ice thickness below the quay was above 2m ice temperature

spectral reflectance properties of ureilites abstract the 0 35 2 6 m reflectance spectra of 18 ureilites have been examined in order to improve our understanding of the spectral reflectance properties of this meteorite class across this spectral range ureilite spectra are characterized by a steep rise in reflectance over the 0 3 to approximately 0 7 m range low overall reflectance 25 and weak mafic iron silicate absorption bands in the 1 and 2 m region the weakness of these bands and the low reflectance are attributed to the presence of dispersed graphite and related carbonaceous phases metal and possibly shock wavelength positions of the mafic silicate absorption bands span a range of values but are consistent with the presence of pyroxene and olivine ureilite spectra generally exhibit blue slopes across the 0 7 2 6 m interval and exhibit many overall similarities to some carbonaceous chondrites the weak features and spectral diversity of ureilites make reflectance spectroscopy based identification of a ureilite parent body challenging as terrestrial alteration of ureilites is prevalent spectral studies of falls are most useful for determining the spectral properties of likely parent bodies

quantitative compositional analysis of martian mafic regions using the mex omega reflectance data 2 petrological implications abstract the primary objectives of this paper are to determine the modal mineralogy of selected low albedo terrains of different ages ranging from noachian to amazonian exposed on the surface of mars this analysis is conducted using the spectral modeling of the observatoire pour la mineralogie l eau les glaces et l activite omega reflectance data results from this work are consistent with the major results of previous spectroscopic studies plagioclase 40 60 in volume and high calcium pyroxene 20 40 hcp are the dominant minerals of the most regions low calcium pyroxene 10 15 lcp and minor amounts of olivine are also present the oldest terrains are characterized by the largest amount of lcp and the lowest concentration of plagioclase these overall compositions are consistent with two pyroxene basalts the particle sizes are in the range of a few hundreds of micrometers which is in good agreement with the thermal inertia of the martian low albedo regions in the region around the nili fossae localized concentrations of olivine up to 40 with millimeter particle size similar to picritic basalts observed in situ by the spirit rover in the gusev crater are inferred chemical compositions are calculated for the first time from omega spectra they are quite consistent with gusev rocks and shergottite compositions but they appear to be significantly sio2 poorer than thermal emission spectrometer data a decreasing low calcium pyroxene abundance with the decreasing age of the low albedo regions is reported this may be indicative of decreasing degree of partial melting as thermal flux decreases with time we propose that the ancient noachian aged lcp rich terrains could have been formed from h2o bearing melts then dry basaltic volcanism occurred leading to decreasing lcp abundance with time due to decreasing degree of partial melting the olivine bearing material modeled in nili fossae resembles the composition of alh77005 and chassigny meteorites consistent with prior studies implications on the formation of the basaltic shergottites are discussed

evidence for komatiite type lavas on mars from phobos ism data and other observations data from the phobos 2 imaging spectrometer for mars ism compiled by mustard et al 1993 and other observations support the existence of komatiitic lavas on mars mustard et al 1993 determined from ism data that the composition of the low albedo materials covering the syrtis major plateau originally consisted of augite bearing basalt containing both augite and pigeonite with no appreciable amount of olivine this description is consistent with a komatiitic basalt komatiite is significant for the earth because it contains a high amount of mgo implying generation under unique circumstances compared to more typical basaltic compositions and may be similarly important for mars

the m x asteroid menagerie results of an nir spectral survey of 45 main belt asteroids abstract diagnostic mineral absorption features for pyroxene s olivine phyllosilicates and hydroxides have been detected in the near infrared nir approximately 0 75 2 50 m spectra for 60 of the tholen classified tholen 1984 1989 m x asteroids observed in this study nineteen asteroids 42 exhibit weak band i approximately 0 9 m band ii approximately 1 9 m absorptions three asteroids 7 exhibit a weak band i approximately 1 05 1 08 m olivine absorption four asteroids 9 display multiple absorptions suggesting phyllosilicate oxide hydroxide minerals one 1 asteroid exhibits an s asteroid type nir spectrum and 18 asteroids 40 are spectrally featureless in the nir but have widely varying slopes tholen m asteroids are defined as asteroids exhibiting featureless visible wavelength spectra with moderate albedos tholen 1989 tholen x asteroids are also defined using the same spectral criterion but without albedo information previous work has suggested spectral and mineralogical diversity in the m asteroid population rivkin et al 1995 2000 busarev 2002 clark et al 2004 hardersen et al 2005 birlan et al 2007 ockert bell et al 2008 2010 shepard et al 2008 2010 fornasier et al 2010 the pyroxene bearing asteroids are dominated by orthopyroxene with several likely to include higher ca clinopyroxene components potential meteorite analogs include mesosiderites cb ch chondrites and silicate bearing nife meteorites the eos family olivine bearing asteroids are most consistent with a co chondrite analog the aqueously altered asteroids display multiple weak absorptions 0 85 0 92 0 97 1 10 1 40 and 2 30 2 50 m indicative of phyllosilicate hydroxide minerals the spectrally featureless asteroids range from metal rich to metal poor with meteorite analogs including nife meteorites enstatite chondrites and stony iron meteorites

e type asteroid spectroscopy and compositional modeling 1 we present near infrared spectroscopic observations 0 8 2 5 m of e type asteroids we combine these observations with visible wavelength spectra obtained by other researchers and perform hapke theory mixing model simulations of e type asteroid spectra in order to constrain possible compositions aubrites were originally suggested as the meteorite analog for the e type asteroids because of their similar visible wavelength colors and high albedos the designation e was originally linked with the mineral enstatite common in aubrite meteorites more recently the sulfides troilite and oldhamite have been suggested as possible components of e type asteroids we tested the suggested compositional interpretations of aubrite meteorites and or aubrites enhanced with sulfides we also tested compositions of aubrites mixed with low iron silicate minerals we find that e types can be separated into three groups on the basis of inferred composition nysa like e types are consistent with silicate mineralogy higher in iron than the mineral enstatite angelina like asteroids are consistent with silicate mineralogy including a sulfide such as oldhamite and hungaria like e types are not inconsistent with aubrites our results indicate that some e type asteroids may be composed of materials that are not sampled by meteorites

determination of the elemental composition of rocks on venus by venera 13 and venera 14 preliminary results venera 13 and venera 14 have determined for the first time ever the elemental composition of the venusian rocks at the probes landing sites to study venusian rocks rolling upland and flat lowland have been chosen as the most typical of the entire planetary surface venera 13 landed on the rolling upland while venera 14 landed in the region with lower topography the chemical composition of the rock at the venera 13 landing site proved to be similar to the composition of potassium alkaline basalts of the earth s crust rocks which can be found on oceanic islands and in rift zones the chemical composition of the rock at the venera 14 landing site is similar to that of tholeiitic basalts of the oceanic crust of the earth the comparison of new data on the composition of venusian rocks with the composition of the rocks of similar provinces on the earth and the moon shows that the evolution of the surface and crust of venus was not similar to that of the earth and especially not that of the moon

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

pyroxene spectroscopy revisited spectral compositional correlations and relationship to geothermometry the authors wish to thank the various agencies which have provided the necessary support for this project including grants in aid of research from sigma xi the scientific research society to e a c the geological society of america grant 3741 87 to e a c and nasa planetary geology and geophysics grant nagw 642 to m j g

oxygen and asteroids hundreds of thousands of asteroids have been discovered in the asteroid belt and in near earth space oxygen is an abundant element in meteorites and presumably in most asteroids spectral reflectance measurements of asteroids in the visible and near infrared can identify oxygen bearing minerals such as those found in the olivine pyroxene and serpentine groups due to their distinctive absorption features interpretation of the mineralogy of asteroids is complicated by the effects of space weathering which tends to redden and darken the surfaces of asteroids asteroids are primarily classified into a number of taxonomic classes and subclasses according to their spectral properties in the visible wavelength region however asteroids with similar spectral properties in the visible may have different spectral properties in the near infrared and therefore different interpreted mineralogies definite trends in the abundances of different taxonomic classes versus heliocentric distance are apparent these trends appear to be a function of both composition differences and degree of heating however dynamical processes have significantly affected these trends close observation of asteroids by spacecraft such as near shoemaker to 433 eros and hayabusa to 25143 itokawa are currently the best way to discern the mineralogies of individual asteroids

three basaltic earth approaching asteroids and the source of the basaltic meteorites we report five color photometry near infrared spectra 0 8 2 5 m and thermal observations of the earth approaching asteroids 3551 1983 rd 3908 1980 pa and 4055 1985 do2 we derive their diameters as 1 2 1 0 and 3 4 km respectively apart from greater absorption band depths the spectra of these three small asteroids are nearly identical to that of vesta which is known to have a differentiated basaltic surface the deeper pyroxene bands 0 9 and 1 9 m relative to vesta are consistent with more pyroxene rich surfaces larger mineral grain sizes in their optically immature regoliths more bare rock surfaces or all of these factors these small earth approaching asteroids have similar orbits with perihelia near earth s orbit in july august they are probably not fragments of vesta but may be fragments of one or more vesta like parent bodies the spectra of vesta and the three earth approachers resemble those of the basaltic meteorites i e eucrites howardites and diogenites hed meteorites we find that hed fall times show a weak peak in july august suggesting that 3551 3908 and 4055 may be fragments of the source bodies of the hed meteorites or perhaps of a single common hed parent body the kilometer size asteroids have regoliths with significant insulating properties but these regoliths differ from that of the moon in that the particle sizes are larger than on the moon and lunar like glasses and agglutinates are largely absent the causes of these differences are related to impact velocities impact shaking and debris retention on small bodies differentiated basalt or mantle like asteroids may have impacted earth and left discontinuities in the geologic climatic record without leaving the chemical signatures associated with the k t boundary event

global occurrence trend of high ca pyroxene on lunar highlands and its implications we present details of the global distribution of high ca pyroxene hcp rich sites in the lunar highlands based on the global data set of hyperspectral reflectance obtained by the selene spectral profiler most hcp rich sites in the lunar highlands are found at fresh impact craters in each crater most of the detection points are distributed on the ejecta rim and floor of the impact craters rather than the central peaks while the central peaks are dominated by purest anorthosite pan this indicates that hcp rich materials originate from relatively shallower regions of the lunar crust than pan in addition while all ray craters with sizes larger than 40 km possess hcp rich materials small fresh craters with sizes less than 6 10 km do not indicating that the uppermost mixing layers in the lunar crust are not dominated by hcp based on these results we propose that in the upper lunar crust a hcp rich zone overlying the pan layer exists below the uppermost mixing layer this hcp rich zone may originate from interstitial melt during the formation of the flotation anorthositic cumulate while an impact ejecta origin impact melt origin and or magmatic intrusion into the upper lunar crust may also account for the occurrence of hcp rich sites in the highlands

using the modified gaussian model to extract quantitative data from lunar soils 1 the lunar soil characterization consortium lscc has examined and characterized a suite of lunar soils with a wide range of compositions and maturities the purpose of this study is to compare the vis nir spectral properties of these lunar soils with their petrologic and chemical compositions using the modified gaussian model mgm to obtain quantitative data about the character of relatively weak near infrared absorption bands useful compositional information can be extracted from high quality soil spectra using the mgm the model had some difficulty fitting absorption bands in the 2 mm region of the lunar spectrum but bands in the 1 and 1 2 mm regions provided physically realistic results the model was able to distinguish high ca and low ca pyroxenes in the lscc suite of lunar soils in the appropriate relative abundance in addition unexpected insights into the nature and causes of absorption bands in lunar soils were identified for example at least two distinct absorption bands are required in the 1 2 mm region of the spectrum and neither of these bands can be attributed to plagioclase or agglutinates but are found instead to be largely due to pyroxene

characterization of the 1 2 μm m1 pyroxene band extracting cooling history from near ir spectra of pyroxenes and pyroxene dominated rocks the 1 2 m band in near infrared spectra of pyroxenes results from fe2 in the m1 crystallographic site the distribution of fe and mg between the m1 and m2 sites is in part a function of the cooling rate and thermal history of a pyroxene combining near infrared and mssbauer spectra for a series of compositionally controlled synthetic mg fe ca pyroxenes we quantify the strength of the 1 2 m band as a function of fe2 in the m1 site near infrared spectra are deconvolved into component absorptions that can be assigned to the m1 and m2 sites using the modified gaussian model the relative strength of the 1 2 m band is shown to be directly related to the amount of fe2 in the m1 site measured by mossbauer spectroscopy the strength of the 1 2 m band relative to the combined strengths of the 1 2 and 2 m bands or the m1 intensity ratio is calculated for 51 howardite eucrite and diogenite hed meteorites diogenites and cumulate eucrites exhibit the lowest m1 intensity ratios consistent with their formation as slowly cooled cumulates basaltic eucrites exhibit a large range of m1 intensity ratios all of which are consistently higher than the diogenites and cumulate eucrites this example illustrates how the m1 intensity ratio can be a used as a tool for characterizing the cooling history of remotely detected pyroxene dominated rocks

a neotaphonomic view of prey demographics and predator preferences at ngamo pan hwange national park zimbabwe waterholes in african savanna ecosystems are often locations of carnivore serial predation at ngamo pan located in hwange national park zimbabwe predators take advantage of natural and artificial waterholes to ambush prey resulting in the a vast accumulation of large mammal bones across the local landscape lions are presumed responsible for many predation occurrences surrounding waterhole locations in hwange national park but attributing prey deaths to a specific predator at ngamo pan can only be hypothesized as most kills occur at night and have not been directly observed here i use several demographic measures of the prey population to evaluate the potential influence of various predators in the accumulation of the ngamo pan bone assemblage known predator preferences relative to prey body size and prey age are drawn from other african national parks and game reserves and used to gauge the impact of lions and other carnivores at ngamo pan in terms of prey body size the preferences of lions are overwhelmingly represented in the ngamo pan death assemblage the abundance of wildebeest and zebra remains reflects the dependence of those species on waterhole locations even when lions are present on the other hand buffalo avoid waterholes in the presence of lions leading to fewer predation occurrences at ngamo pan wildebeest and zebra age profiles do not conform to other known patterns of death generated by specific carnivores but rather reflect the influences of multiple predators these data on prey demographics coupled with landscape and environmental data are important for understanding the dynamics and underlying mechanics of predator prey relationships at ngamo pan such mechanisms are likely to be long standing features of african savanna ecosystems and can be useful in predicting predator prey relationships in fossil bone assemblages from similar waterhole localities

the lunar rock and mineral characterization consortium deconstruction and integrated mineralogical petrologic and spectroscopic analyses of mare basalts the lunar rock and mineral characterization consortium lrmcc has conducted coordinated mineralogy petrography spectroscopy analyses of a suite of pristine lunar basalts four basalt slabs two low ti two high ti and paired thin sections were analyzed thin sections were analyzed for mineralogy petrography while the slabs were used to prepare particulate separates of major mineral phases and bulk samples mineral separates and particulate bulk samples were crushed to controlled grain sizes and their reflectance spectra measured in the nasa relab at brown university the resulting data set provides an essential foundation for spectral mixing models offers valuable endmember constraints for space weathering analyses and represents critical new ground truth results for lunar science and exploration efforts

mineralogical analysis of the oppia quadrangle of asteroid 4 vesta evidence for occurrence of moderate reflectance hydrated minerals abstract quadrangle av 10 oppia is one of five quadrangles that cover the equatorial region of asteroid 4 vesta this quadrangle is notable for the broad spectrally distinct ejecta that extend south of the oppia crater these ejecta exhibit the steepest reddest visible spectral slope observed across the asteroid and have distinct color properties as seen in multispectral composite images compared to previous works that focused on the composition and nature of unusual orange ejecta found on vesta here we take into account a broader area that includes several features of interest with an emphasis on mineralogy as inferred from data obtained by dawn s visible infrared mapping spectrometer vir our analysis shows that the older northern and northeastern part of av 10 is dominated by howardite like material while the younger southwestern part including oppia and its ejecta blanket has a markedly eucritic mineralogy the association of the mineralogical information with the geologic and topographic contexts allows for the establishment of relationships between the age of the main formations observed in this quadrangle and their composition a major point of interest in the oppia quadrangle is the spectral signature of hydrous material seen at the local scale this material can be mapped by using high resolution vir data combined with multispectral image products from the dawn framing camera fc so as to enable a clear correlation with specific geologic features hydrated mineral phases studied previously on vesta generally correlate with low albedo material delivered by carbonaceous asteroids however our analysis shows that the strongest oh signature in av 10 is found in a unit west of oppia previously mapped as light mantle material and showing moderate reflectance and a red visible slope with the available data we cannot yet assess the presence of water in this material however we offer a possible explanation for its origin

a systematic mapping procedure based on the modified gaussian model to characterize magmatic units from olivine pyroxenes mixtures application to the syrtis major volcanic shield on mars clenet et al 2011 have developed an adapted version of the modified gaussian model mgm the improvements allow the characterization of spectra of olivine pyroxene s mixtures addressing both modal composition and individual minerals chemical composition this version of mgm is fully automated and operational with large amounts of hyperspectral imaging data two natural cases are considered the first one is the sumail massif in the oman ophiolite earth based on our approach applied to hymap data two contrasted lithologic units are mapped the mantle which is harzburgite dominated and the crust made of gabbros and clinopyroxene rich cumulates with spectral variations interpreted in terms of pyroxenes chemical compositions once this new mgm mapping approach has been validated on a controlled natural situation we map the distribution of mafic assemblages across the syrtis major volcano on mars using a visible and near infrared vnir short wave infrared swir observatoire pour la mineralogie l eau les glaces et l activite omega mars express mex mosaic our results are in agreement with previous work but olivine appears to be more abundant than previously estimated in the central part of the volcanic edifice especially in ternary mafic assemblages augite olivine enstatite based on these results we propose a possible scenario for the igneous and thus thermal evolution of the syrtis major region surrounding terrains have formed first and local heterogeneity can be observed between northern and southern areas of the noachian crust we also observe variations in the mineral assemblages within syrtis major lavas which can be interpreted in terms of differentiation from a common parent melt and or of a progressive evolution of the mantle source composition and temperature key points mgm systematic mapping on syrtis major to characterize mafic minerals mixtures olivine and pyroxenes mixture is detected in the central lavas of the volcano pyroxenes have chemical compositions spanning the enstatite augite range

the spectral parameter maps of vesta from vir data abstract here we present the spectral parameter maps used in this surface composition of vesta special issue the use of spectral parameters have been important since the first ground based observations of vesta as they can describe single mineralogic aspects as abundances or change in surface composition mapping these parameters over the surface shows the mineralogic diversity across the asteroid vesta in this work we discuss the development of the maps which are produced from the data of the visible and infrared mapping spectrometer onboard nasa s dawn mission we describe how we processed the vir spectra and how we produced the geometries of data acquisition spectra and geometries are used to design a geographic information system procedure to mosaic these data we conclude the article with a description of the trends of the pyroxene related spectral parameters across the asteroid and some statistics on the spectral parameters of each map within the quadrangle based scheme used in this special issue

quantitative compositional analysis of martian mafic regions using the mex omega reflectance data 1 methodology uncertainties and examples of application abstract the mars express observatoire pour la mineralogie l eau les glaces et l activite omega collected an unprecedented visible and near infrared hyperspectral dataset covering the low albedo regions of mars we investigate the ability to infer modal abundance of surfaces of these regions from a radiative transfer model developed by shkuratov et al shkuratov y starukhina l hoffmann h arnold g 1999 icarus 137 235 246 and adapted to basaltic surfaces by poulet and erard poulet f erard s 2004 j geophys res 109 e2 doi 10 1029 2003je002179 from omega measurements of mafic surfaces we develop several sensitivity tests to assess the extent to which the model can be applied to predict pyroxene composition high calcium phase and low calcium phase abundance of almost neutral components plagioclase in the near infrared wavelength as well as grain sizes by using a library of selected end members results of the sensitivity tests indicate that the scattering model can estimate both abundances and grain sizes of major basaltic materials of low albedo regions within uncertainties 5 to 15 vol the model is then applied to data from dissected cratered terrains located in terra meridiani the derived grain size including uncertainties is in the 50 500 m range this is consistent with the thermal inertia and albedo of this region which indicates a fine sand sized surface with little dust the abundances of plagioclase 43 57 and pyroxenes 35 45 10 including 11 5 of low calcium phase are in good agreement with previous basalt like compositions of low albedo regions from thermal infrared spectral measurements the method presented in this paper will provide a valuable tool for evaluating the modal mineralogy of other mafic regions of mars observed in the near infrared wavelength range

mineralogy of the lunar crust results from clementine received 1997 december 5 accepted in revised form 1998 september 15 abstract the central peaks of 109 impact craters across the moon are examined with clementine ultraviolet visible uvvis camera multispectral data the craters range in diameter from 40 to 180 km and are believed to have exhumed material from 5 30 km beneath the surface to form the peaks including both upper and lower crustal rocks depending on whether craters have impacted into highlands or basins representative five color spectra from spectrally and spatially distinct areas within the peaks are classified using spectral parameters including key ratio which is related to mafic mineral abundance and spectral curvature linked to absorption band shape which distinguishes between low and high ca pyroxene and olivine the spectral parameters are correlated to mineralogical abundances related in turn to highland plutonic rock compositions the derived rock compositions for the various central peaks are presented in a global map from these results it is evident that the lunar crust is compositionally diverse both globally and at local 100 m scales found within individual sets of central peaks although the central peaks compositions imply a crust that is generally consistent with previous models of crustal structure they also indicate a more anorthositic crust than generally assumed with a bulk plagioclase content of 8 1 evolving from pure anorthosite near the surface towards more mafic low ca pyroxene rich compositions with depth comparable to anorthositic norite evidence for mafic plutons occurs in both highlands and basins and represent all mafic highland rock types however the lower crust is more compositionally diverse than the highlands with both a greater range of rock types and more diversity within individual sets of central peaks

near infrared spectral reflectance of mineral mixtures systematic combinations of pyroxenes olivine and iron oxides near infrared spectral reflectance data are presented for systematic variations in weight percent of two component mixtures of ferromagnesian and iron oxide minerals mixtures were chosen for application to the study of the dark materials on mars but the results are equally applicable to mafic and ultramafic assemblages elsewhere in the solar system olivine spectral features are greatly reduced in contrast by admixture of other phases but remain distinctive even for low olivine contents clinopyroxene and orthopyroxene mixtures show resolved pyroxene absorptions near 2 m the addition of limonite greatly modifies pyroxene and olivine reflectance but does not fully eliminate distinctive spectral characteristics using only spectral data in the 1 m region it is difficult to differentiate orthopyroxene and limonite goethite in a mixture additional spectral coverage or other evidence may be required for a unique interpretation all composite mineral absorptions observed in this study are either weaker than or intermediate in strength to the end member absorptions and have bandwidths greater than or equal to those for the end members in general spectral properties in an intimate mixture combine in a complex nonadditive manner with features demonstrating a regular but usually nonlinear variation as a function of end member phase proportions

abundance and distribution of iron on the moon the abundance and distribution of iron on the moon is derived from a near global data set from clementine the determined iron content of the lunar highlands crust 3 percent iron by weight supports the hypothesis that much of the lunar crust was derived from a magma ocean the iron content of lower crustal material exposed by the south pole aitken impact basin on the lunar farside is higher 7 to 8 percent by weight and consistent with a basaltic composition this composition supports earlier evidence that the lunar crust becomes more mafic with depth the data also suggest that the bulk composition of the moon differs from that of the earth9s mantle this difference excludes models for lunar origin that require the earth and moon to have the same compositions such as fission and coaccretion and favors giant impact and capture

surface composition and taxonomic classification of a group of near earth and mars crossing asteroids abstract in the past constraining the surface composition of near earth asteroids neas has been difficult due to the lack of high quality near ir spectral data 0 7 2 5 m that contain mineralogically diagnostic absorption bands here we present visible 0 43 0 95 m and near infrared 0 7 2 5 m spectra of nine neas and five mars crossing asteroids mcs the studied neas are 4055 magellan 19764 2000 nf5 89830 2002 ce 138404 2000 ha24 143381 2003 bc21 159609 2002 aq3 164121 2003 yt1 241662 2000 ko44 and 2007 ml13 the studied mcs are 1656 suomi 2577 litva 5407 1992 ax 22449 ottijeff and 47035 1998 ws the observations were conducted with the ntt at la silla chile the 2 2 m telescope at calar alto spain and the irtf on mauna kea hawai i the taxonomic classification bus system of asteroids showed that all observed mc asteroids belong to the s complex including the s sr and sl classes seven of the neas belong to the s complex including the s sa sk and sl classes and two neas were classified as v types the classification of the nea 164121 2003 yt1 as a v type was made on the basis of its near infrared spectrum since no visible spectrum is available for this asteroid a mineralogical analysis was performed on six of the asteroids those for which near ir spectra were obtained or previously available we found that three asteroids 241662 2000 ko44 19764 2000 nf5 138404 2000 ha24 have mafic silicate compositions consistent with ordinary chondrites while three others 4055 magellan 164121 2003 yt1 5407 1992 ax are pyroxene dominated basaltic achondrite assemblages in the case of 5407 1992 ax we found that its basaltic surface composition contrasts its taxonomic classification as a s type

mineralogical survey of the anorthositic feldspathic highlands terrane crust using moon mineralogy mapper data abstract spectroscopic data from the moon mineralogy mapper m 3 instrument are used to study the mineralogy of the central peak or peak ring of 75 craters located in the lunar anorthositic feldspathic highlands terrane fht a as defined by jolliff et al 2000 the thickness of south pole aitken spa ejecta at the location of the selected craters is estimated crustal thickness models are used with empirical cratering equations to estimate the depth of origin of the material excavated in the studied central peaks and its distance to the crust mantle interface the goal of this survey is to study the composition of the fht a crust and the extent of its potential lateral and vertical heterogeneities high calcium pyroxene hcp and featureless spectra are mostly detected throughout the entire fht a whereas the number of pure plagioclase detections is small no relationship between the central peak composition and the distance to spa or the depth within the spa ejecta is observed the spa ejecta material cannot be spectrally distinguished from crustal material we interpret the paucity of plagioclase spectra in the fht a which contrasts with more frequent plagioclase detections in the central peaks of craters sampling the crust in younger lunar terranes using identical spectroscopic techniques martinot et al 2018b as a possible effect of terrane maturation or of mixing with mafic components that mask their signature in the visible near infrared overall the fht a appears homogeneous laterally however data hint at a pyroxene compositional change with increasing depth from high calcium content in the upper crust towards less calcic compositions with increasing depth which is consistent with prior studies of the architecture of the lunar crust

the ungrouped chondrite el medano 301 and its comparison with other reduced ordinary chondrites abstract el medano 301 em 301 is an ungrouped chondrite with overall texture and trace element distribution similar to those of ordinary chondrites ocs but with silicate olivine and low ca pyroxene compositions that are more reduced than those in ocs with average olivine and low ca pyroxene of fa3 9 0 3 and fs12 8 4 9 respectively these values are far lower than the values for ocs and even for chondrites designed as reduced chondrites low ca pyroxene is the dominant mineral phase and shows zoning with higher mgo contents along the crystal rims and cracks reverse zoning the co content of kamacite is also much lower than the concentrations observed in ocs below detection limit of 0 18 wt versus 0 44 37 wt oxygen isotopic composition is 17o 0 79 0 78 and slightly different from that of ocs the lower modal olivine pyroxene ratio different infrared ir spectra lower co content of kamacite lower mean feo contents of olivine and pyroxene different kamacite texture and different oxygen isotopic composition show that em 301 does not belong to a known oc group em 301 shows similarities with chondritic clasts in cumberland falls aubrite and with northwest africa 7135 nwa 7135 and acfer 370 ungrouped chondrites however dissimilar to nwa 7135 and the clasts it does not contain highly reduced mineral phases like daubreelite our observations suggest the formation of em 301 in a nebular region compositionally similar to ocs but with a different redox state with oxygen fugacity o2 in this region lower than that of ocs and higher than that of enstatite chondrites condensation region a second possibly nebular phase of reduction by the production of reducing gas phases e g c rich could be responsible for the subsequent reduction of the primary material and the occurrence of reverse zoning in the low ca pyroxene and lower average fa fs ratio based on the ir spectra of em 301 we suggest the possibility that the parent body of this chondrite was a v type asteroid

vnir spectral variability of the igneous stratified stillwater complex a tool to map lunar highlands lunar highlands are plagioclase rich terrains produced by crystal floating in a magma ocean system lunar samples revealed the presence of anorthositic plagioclase 90 samples from the highlands associated to more mafic rocks recently remote sensing data permit mapping those terrains with high spatial and spectral resolution allowing detection of plagioclase and mafic crystal field c f absorptions in this paper we have studied bidirectional spectral characteristics in the visible near infrared vnir of rocks from the stillwater complex a cumulitic igneous stratified complex with composition varying from mafic to sialic e g pyroxenite anorthosite we investigated both slabs and powders of these rocks to give indication of the spectral variability of rock analogs of lunar crust from a mineralogical point of view samples have been spectrally separated in four main groups considering the different c f absorption association reflectance and spectral shape for both slab and powder spectra more spectral details can be obtained from the analysis of powder spectra than from the slab spectra the composition of rocks can be addressed by studying spectral parameters such as the position and the intensity of the absorption e g band center and band depth the analysis of our plagioclase pyroxene bearing samples indicates that mafic composition can be clearly obtained for samples characterized by one pyroxene phase even for few amounts of pyroxene from powder spectra on the other hand slab spectra show clear pyroxene absorptions only for rocks with mafic abundance at least 20 the intensity of the mafic absorptions of these samples shows a linear trend with respect to the abundance of pyroxenes orthopyroxene clinopyroxene for samples with ferrosilite amount less than ca 25 considering all pyroxene bearing samples the band depth of slab spectra are linearly related to the volumetric distribution of ferrous iron in pyroxenes

aster detection of chromite bearing mineralized zones in semail ophiolite massifs of the northern oman mountains exploration strategy abstract economically viable chromite deposit occurrences are widespread in the ultramafic rocks of semail ophiolite massifs of the northern oman mountains particularly in the basal dunite and harzburgite unit of the mantle section geological mapping of this region is challenging primarily due to difficult access complexity of structures and lack of resolution and areal integrity of lithological differentiation using conventional mapping techniques the present research study evaluates the discrimination and occurrence of chromites bearing mineralized zones within ophiolites by analyzing the capabilities of landsat tm and advanced spaceborne thermal emission and reflection radiometer aster satellite data using a number of selected methods including decorrelated stretching different band rationing and principal component analysis image processing techniques exist in the scientific literature the study results show that the processed vnir and swir spectral wavelength regions are promising in detecting the areas of potential chromite bearing mineralized zones within the ophiolite region and proved to be successful for mapping of serpentinized harzburgite containing chromites exploration geologists industrialists and mine owners are advised to adopt this technique and avoid the limits in filed data alone for more exploration and exploitation of areas having chromite deposits in arid region elsewhere

complexities in pyroxene compositions derived from absorption band centers examples from apollo samples hed meteorites synthetic pure pyroxenes and remote sensing data we reexamine the relationship between pyroxene composition and near infrared absorption bands integrating measurements of diverse natural and synthetic samples we test an algorithm plc involving a two part linear continuum removal and parabolic fits to the 1 and 2 m bands a computationally simple approach which can easily be automated and applied to remote sensing data employing a suite of synthetic pure pyroxenes the plc technique is shown to derive similar band centers to the modified gaussian model plc analyses are extended to natural pyroxene bearing materials including 1 bulk lunar basalts and pyroxene separates 2 diverse lunar soils and 3 hed meteorites for natural pyroxenes the relationship between composition and absorption band center differs from that of synthetic pyroxenes these differences arise from complexities inherent in natural materials such as exsolution zoning mixing and space weathering for these reasons band center measurements of natural pyroxene bearing materials are compositionally nonunique and could represent three distinct scenarios 1 pyroxene with a narrow compositional range 2 complexly zoned pyroxene grains or 3 a mixture of multiple pyroxene or nonpyroxene components therefore a universal quantitative relationship between band centers and pyroxene composition cannot be uniquely derived for natural pyroxene bearing materials without additional geologic context nevertheless useful relative relationships between composition and band center persist in most cases these relationships are used to interpret m3 data from the humboldtianum basin four distinct compositional units are identified 1 mare humboldtianum basalts 2 distinct outer basalts 3 low ca pyroxene bearing materials and 4 feldspathic materials

observations on elephant mortality and bones in water holes an unusually severe drought in 1982 led to a temporary die off of elephants at a natural water source in hwange national park zimbabwe compared to living populations the age structure of the animals killed by drought is strongly biased toward 2 to 8 year old animals however the fresh carcasses of these young elephants were commingled with weathered remains of adults that had died earlier creating a mixed skeletal sample whose age structure was much closer to that of living populations observations of elephant bones that have accumulated due to natural mortality at water holes might provide analogs for paleoecological interpretations of fossil proboscidean assemblages

revisiting spectral parameters of silicate bearing meteorites visible and near infrared reflectance spectra of a sample of silicate bearing meteorites have been used to evaluate the spectral parameters space defined in the pioneering work of gaffey et al 1993 the studied sample consisted of 91 ordinary chondrites 47 basaltic achondrites and 21 different laboratory mixtures obtained from the relab database our results indicate that the spectral parameter space in particular the bar versus band i center is not suitable enough to identify the mineralogy of meteorites and asteroids the grain size of the sample also appears as a very sensitive parameter and can play an important role in locating an object in the spectral parameter space finally the application of our study to the question of a genetic link between v type asteroids and hed meteorites shows that these bodies plot in distinct regions in the bar versus band i center space this result further confirms that those spectral parameters cannot uniquely define the mineralogy of a sample

sulfates and iron oxides in ophir chasma mars based on omega and crism observations abstract we investigate the sulfate and iron oxide deposits in ophir chasma mars based on short wave infrared data from the compact reconnaissance imaging spectrometer for mars crism and from the observatoire pour la mineralogie l eau les glaces et l activite omega sulfates are detected mainly in two locations in the valley between ophir mensa and the southern wall of ophir chasma kieserite is found both within the slope of ophir mensa and superposed on the basaltic wall of the chasm here kieserite is unconformably overlain by polyhydrated sulfate deposits and iron oxides locally jarosite and unidentified phases with absorptions at 2 21 m or 2 23 m are detected which could be mixtures of jarosite and amorphous silica or other poorly crystalline phases the second large sulfate rich outcrop is found on the floor of the central valley although the same minerals are found here polyhydrated sulfates kieserite iron oxides and locally a possibly jarosite bearing phase this deposit is very distinct it is not layered almost horizontal and located at a much lower elevation of below 4250 m kieserite superposes polyhydrated sulfate rich deposits and iron oxides form lags the facies of sulfate formation remains unclear and could be different for the two locations a formation in a lake playa or under a glacier is consistent with the mineralogy of the central valley and its flat low lying topography this is not conceivable for the kieserite deposits observed south of ophir mensa these deposits are observed over several thousands of meters of elevation which would require a standing body of water several thousands of meters deep this would have lead to much more pervasive sulfate deposits than observed these deposits are therefore more consistent with evaporation of groundwater infiltrating into previously sulfate free light toned deposits the overlying polyhydrated sulfates and other mineral phases are observed in outcrops on ridges along the slopes of the southern chasm wall which are too exposed to be reached by groundwater here a water supply from the atmosphere by rain snow fog or frost is more conceivable

space weathering on eros constraints from albedo and spectral measurements of psyche crater we present combined multi spectral imager msi 0 95 m and near infrared spectrometer nis 0 8 2 4 m observations of psyche crater on s type asteroid 433 eros obtained by the near earth asteroid rendezvous near shoemaker spacecraft at 5 3 km in diameter psyche is one of the largest craters on eros which exhibit distinctive brightness patterns consistent with downslope motion of dark regolith material overlying a substrate of brighter material at spatial scales of 620 m spectrum psyche crater wall materials exhibit albedo contrasts of 32 40 at 0 946 m associated spectral variations occur at a much lower level of 4 8 2 4 we report results of scattering model and lunar analogy investigations into several possible causes for these albedo and spectral trends grain size differences olivine pyroxene and troilite variations and optical surface maturation we find that the albedo contrasts in psyche crater are not consistent with a cause due solely to variations in grain size olivine pyroxene or lunar like optical maturation a grain size change sufficient to explain the observed albedo contrasts would result in strong color variations that are not observed olivine and pyroxene variations would produce strong band correlated variations that are not observed a simple lunar like optical maturation effect would produce strong reddening that is not observed the contrasts and associated spectral variation trends are most consistent with a combination of enhanced troilite a dark spectrally neutral component simulating optical effects of shock and lunar like optical maturation these results suggest that space weathering processes may affect the spectral properties of eros materials causing surface exposures to differ optically from subsurface bedrock however there are significant spectral differences between eros proposed analog meteorites ordinary chondrites and or primitive achondrites and eros freshest exposures of subsurface bright materials after accounting for all differences in the measurement units of our reflectance comparisons we have found that the bright materials on eros have reflectance values at 0 946 m consistent with meteorites but spectral continua that are much redder than meteorites from 1 5 to 2 4 m most importantly we calculate that average eros surface materials are 30 40 darker than meteorites

mg spinel lithology a new rock type on the lunar farside 1 high resolution compositional data from moon mineralogy mapper m3 for the moscoviense region on the lunar farside reveal three unusual but distinctive rock types along the inner basin ring these are designated oos since they are dominated by high concentrations of orthopyroxene olivine and mg rich spinel respectively the oos occur as small areas each a few kilometers in size that are widely separated within the highly feldspathic setting of the basin rim although the abundance of plagioclase is not well constrained within the oos the mafic mineral content is exceptionally high and two of the rock types could approach pyroxenite and harzburgite in composition the third is a new rock type identified on the moon that is dominated by mg rich spinel with no other mafic minerals detectable 5 pyroxene olivine all oos surfaces are old and undisturbed since basin formation they are effectively invisible in image data and are only recognized by their distinctive composition identified spectroscopically the origin of these unusual lithologies appears to be linked to one or more magmatic intrusions into the lower crust perhaps near the crust mantle interface processes such as fractional crystallization and gravity settling within such intrusions may provide a mechanism for concentrating the mafic components within zones several kilometers in dimension the oos are embedded within highly anorthositic material from the lunar crust they may thus be near contemporaneous with crustal products from the cooling magma ocean

high calcium pyroxene as an indicator of igneous differentiation in asteroids and meteorites our analyses of high quality spectra of several s type asteroids 17 thetis 847 agnia 808 merxia and members of the agnia and merxia families reveal that they include both low and highcalcium pyroxene with minor amounts of olivine 0 4 high calcium pyroxene is a spectrally detectable and petrologically important indicator of igneous history and may prove critical in future studies aimed at understanding the history of asteroidal bodies the silicate mineralogy inferred for thetis and the merxia and agnia family members requires that these asteroids experienced igneous differentiation producing broadly basaltic surface lithologies together with 4 vesta and its smaller vestoid family members and the main belt asteroid 1489 magnya these new asteroids provide strong evidence for igneous differentiation of at least five asteroid parent bodies based on this analysis of a small subset of the near infrared asteroid spectra taken to date with spex at the nasa irtf we expect that the number of known differentiated asteroids will increase consistent with the large number of parent bodies inferred from studies of iron meteorites

new insights into lunar petrology distribution and composition of prominent low ca pyroxene exposures as observed by the moon mineralogy mapper m3 1 lunar geochemical groups such as mg suite ferroan anorthosite and alkali suite rocks are difficult to distinguish from orbit because they are defined by both modal mineralogy and elemental composition of their constituent minerals while modal mineralogy can be modeled only specific minerals or elements can be directly detected at near infrared nir wavelengths pyroxenes are among the most spectrally distinctive minerals and their absorption bands are sensitive to structure and composition pyroxenes thus provide important clues to distinguish these geochemical groups and to understand lunar crustal evolution using moon mineralogy mapper data we search for lithologies dominated by strong low calcium pyroxene lcp signatures we compare the nir absorptions of 20 lcps to a suite of synthetic pyroxenes to determine which lunar pyroxenes appear magnesian enough to be candidate mg suite norites we detail three prominent regions of lcp 1 in south pole aitken basin spa 2 south of mare frigoris and 3 north of mare frigoris the absorption band positions suggest that the lcps north of mare frigoris and those in spa are compositionally similar to one another and of mg50 75 implying that the mafic material excavated by the spa impact was relatively iron rich modified gaussian modeling results suggest that the apollo basin may have tapped different composition material than is exposed in much of spa the lcps located in the highlands south of mare frigoris exhibit absorption bands at short wavelengths consistent with mg 80 the coincidence of these mg rich lcps with the thorium measured by lunar prospector make them good candidates for kreep related mg suite pyroxenes

geoarchaeology and geochronology of the miami clovis site southern high plains of texas abstract the miami site excavated in 1937 is in a small playa basin on the high plains surface the site is one of the earliest documented co occurrences of clovis points and mammoth reinvestigation of the site and related collections was undertaken to better understand the stratigraphy geochronology and archaeology the basin 23 m diameter 1 6 m deep filled with 1 dark gray silty clay and 2 near the top of the section a lens of well sorted silt or loess the basin started to fill ca 13 700 yr b p the loess dates to ca 11 400 yr b p and the bone bed probably dates to ca 11 400 10 500 yr b p the loess may be the local manifestation of a clovis drought the partial remains of five mammoths three adults and two juveniles were recovered in 1937 no other animal remains are known the bone is heavily weathered and there are no clear indications of human modification artifacts found at the site include three clovis points and a scraper found among the bones and two flakes and a scraper found on the surface near the playa the origins of the bone and stone assemblage are uncertain but four scenarios are offered a successful mammoth kill an unsuccessful kill with wounded animals dying at the watering hole opportunistic scavenging following natural deaths or a palimpsest of multiple deaths following both natural and human causes

an in depth look at the lunar crater copernicus exposed mineralogy by high resolution near infrared spectroscopy abstract newly acquired sequentially spaced high resolution near infrared spectra across the central section of crater copernicus interior have been analyzed using a range of complementary techniques and indexes we have developed a new interpretative method based on a multiple stage normalization process that appears to both confirm and expand on previous mineralogical estimations and mapping in broad terms the interpreted distribution of the principle mafic species suggests an overall composition of surface materials dominated by calcium poor pyroxenes and minor olivine but with notable exceptions the southern rim displays strong ca rich pyroxene absorption features and five other locations the uppermost northern crater wall opposite rim sections facing the crater floor and the central peak pk1 and at the foot of pk3 show instead strong olivine signatures we also propose impact glass an alternative interpretation to the source of the weak but widespread olivine like spectral signature found in low reflectance samples since it probably represents a major regolith constituent and component in large craters such as copernicus the high quality and performance of the sir 2 data allows for the detection of diagnostic key mineral species even when investigating spectral samples with very subdued absorption features confirming the intrinsic high quality value of the returned data

volcanic glass signatures in spectroscopic survey of newly proposed lunar pyroclastic deposits moon mineralogy mapper spectroscopic observations are used to assess the mineralogy of five sites that have recently been proposed to include lunar dark mantle deposits dmds volcanic glasses have for the first time clearly been identified at the location of three of the proposed pyroclastic deposits this is the first time that volcanic glasses have been identified at such a small scale on the lunar surface from remote sensing observations deposits at birt e schluter and walther a appear to be glassy dmds deposits at birt e and schluter show 1 morphological evidence suggesting a likely vent and 2 mineralogical evidence indicative of the presence of volcanic glasses the walther a deposits although they show no morphological evidence of vents have the spectroscopic characteristics diagnostic of volcanic glasses the deposits of the freundlich sharonov basin are separated in two areas 1 the buys ballot deposits lack mineralogical and morphological evidence and thus are found to be associated with mare volcanism not with dmds and 2 the anderson crater deposits which do not exhibit glassy dmd signatures but they appear to be associated with possible vent structures and so may be classifiable as dmds finally dark deposits near the crater kopff are found to be associated with likely mare volcanism and not associated with dmds the spectral identification of volcanic glass seen in many of the potential dmds is a strong indicator of their pyroclastic origin

mineralogic and compositional properties of martian soil and dust results from mars pathfinder mars pathfinder obtained multispectral elemental magnetic and physical measurements of soil and dust at the sagan memorial station during the course of its 83 sol mission we describe initial results from these measurements concentrating on multispectral and elemental data and use these data along with previous viking snc meteorite and telescopic results to help constrain the origin and evolution of martian soil and dust we find that soils and dust can be divided into at least eight distinct spectral units based on parameterization of imager for mars pathfinder imp 400 to 1000 nm multispectral images the most distinctive spectral parameters for soils and dust are the reflectivity in the red the red blue reflectivity ratio the near ir spectral slope and the strength of the 800 to 1000 nm absorption feature most of the pathfinder spectra are consistent with the presence of poorly crystalline or nanophase ferric oxide s sometimes mixed with small but varying degrees of well crystalline ferric and ferrous phases darker soil units appear to be coarser grained compacted and or mixed with a larger amount of dark ferrous materials relative to bright soils nanophase goethite akaganeite schwertmannite and maghemite are leading candidates for the origin of the absorption centered near 900 nm in imp spectra the ferrous component in the soil cannot be well constrained based on imp data alpha proton x ray spectrometer apxs measurements of six soil units show little variability within the landing site and show remarkable overall similarity to the average viking derived soil elemental composition differences exist between viking and pathfinder soils however including significantly higher s and cl abundances and lower si abundances in viking soils and the lack of a correlation between ti and fe in pathfinder soils no significant linear correlations were observed between imp spectral properties and apxs elemental chemistry attempts at constraining the mineralogy of soils and dust using normative calculations involving mixtures of smectites and silicate and oxide minerals did not yield physically acceptable solutions we attempted to use the pathfinder results to constrain a number of putative soil and dust formation scenarios including palagonitization and acid fog weathering while the pathfinder soils cannot be chemically linked to the pathfinder rocks by palagonitization this study and mcsween et al 1999 suggest that palagonitic alteration of a martian basaltic rock plus mixture with a minor component of locally derived andesitic rock fragments could be consistent with the observed soil apxs and imp properties

the effects of dental wear on impairing mammoth taxonomy a reappraisal of the newton mammoth bradford county northeastern pennsylvania a mammoth skeleton found at the newton site a kettle lake 15 km southeast of towanda pennsylvania has been referred to mammuthus columbi on the basis of its high narrow skull however the specimen s thin enamel 1 3 1 8 mm and moderately high lamellar frequency 8 8 75 lophs dm resemble some specimens of mammuthus primigenius prehistoric range maps show that a columbian mammoth inhabiting the towanda area would be a significant outlier from this species range however its location would align well with the range of m primigenius to better ascertain the newton mammoth s identification we examine herein the effects of dental wear on the morphology of mammoth molars as mammoth molars wear the enamel lophs become more broadly spaced and the enamel ridges thicken towards the base of the crown thus an older m primigenius with extensively worn molars might display thicker enamel and a lower lamellar frequency and might therefore appear to be a columbian mammoth on the basis of dental morphology alone our results show that the molars of the newton mammoth are well worn and are characterized by an enamel thickness and lamellar frequency that aligns better with m primigenius than with m columbi we conclude that one must take into account the effects of dental wear when classifying mammoth species using solely molars

effects of temperature on remotely sensed mineral absorption features laboratory spectral reflectance of mafic silicates has been measured over a temperature range characteristic of solar system objects to study the variation of diagnostic mineral absorption bands this information has become increasingly important with recent improvements in the quality of remotely sensed planetary data and the concurrent increase in sophistication of quantitative and qualitative spectrum analysis techniques in this study visible and near ir reflectance spectra 0 4 2 5 m of pyroxenes and olivine were obtained over a sample temperature range of 80 448 k these are the first published reflectance data for these minerals at temperatures significantly below ambient 300 k additionally thermal radiation emitted from the samples at elevated temperatures was effectively removed disclosing for the first time the high temperature reflectance behavior of pyroxenes in the diagnostic 2 m spectral region as expected from basic physical considerations fe2 crystal field absorptions in all samples become narrower with decreasing temperature the three components of the composite olivine band centered near 1 m become better resolved with decreased temperature and show changes in relative absorption strength there is not however any significant wavelength shift of the olivine reflectance minimum both orthopyroxene and clinopyroxene spectra show dramatic changes in band symmetry with temperature with the greatest change in the longer wavelength edge despite these significant changes in shape little if any change is observed in the wavelength position of reflectance minima of pyroxene absorptions near 1 m the 2 m pyroxene absorptions in contrast demonstrate major shifts of reflectance minima but in different directions in orthopyroxene spectra the band shifts to longer wavelengths with increased temperature while for the clinopyroxene spectra the band shifts to shorter wavelengths this behavior results in greatly improved spectral differentiation of orthopyroxene and clinopyroxene components in a mixture such as a basalt at reduced temperatures application of the results presented here to remote sensing mineral characterization techniques currently in use for determination of pyroxene composition can provide a moderate improvement to quantitative interpretations from 5 to 20 wt feo for orthopyroxenes and 5 wt cao for clinopyroxenes depending on planetary surface temperature

near ir spectral evidence for the presence of iron poor orthopyroxenes on the surfaces of six m type asteroids abstract the first verifiable near infrared absorption features in the 0 9 m spectral region are reported for asteroids 16 psyche 69 hesperia 110 lydia 125 liberatrix 201 penelope and 216 kleopatra these weak features 1 3 are attributed to orthopyroxenes present on the surfaces of these asteroids 16 psyche and 125 liberatrix have full rotational coverage while 69 hesperia 110 lydia 201 penelope and 216 kleopatra have 75 rotational coverage qualitative 2 m absorption features are present but are very weak 1 absorption band positions suggest relatively low abundances of calcium and iron in the pyroxenes this indicates relatively reducing redox conditions for these asteroids their parent bodies and the nebular regions in which they formed four potential interpretations for these asteroids include 1 they are exposed metallic cores or core fragments of differentiated parent bodies with residual orthopyroxene mantle material 2 they are the result of a smelting like reaction that converts olivine to pyroxene and metallic iron in the presence of carbon at high temperatures 3 they are analogs to the primitive metal rich bencubbinite meteorites or 4 they represent metallic surfaces which have accumulated silicate debris from external sources of the two original interpretations for the m asteroids the enstatite chondrite interpretation chapman and salisbury 1973 icarus 19 507 522 gaffey and mccord 1979 mineralogical and petrological characterizations of asteroids in gehrels t ed asteroids univ of arizona press tucson pp 688 723 can be eliminated for these asteroids because the pyroxene in enstatite chondrites is iron free and does not exhibit such absorption features the iron meteorite interpretation remains valid but with modification for m asteroids 16 psyche and 216 kleopatra these spectral results combined with previous determinations of high radar albedos indicate that these bodies are most probably exposed core fragments of differentiated bodies m asteroids 69 hesperia 110 lydia 125 liberatrix and 201 penelope exhibit similar spectral features consistent with exposed core fragments but radar observations would be needed to confirm a high metal abundance observations of m asteroids 136 austria and 325 heidelberga suggest the absence of absorption features in the 0 4 to 2 5 m region within the scatter of the data verification of the presence or absence of features across the surfaces of these two asteroids requires full rotational coverage the interpretations for these featureless m asteroids are not well constrained but remain consistent with the iron meteorite and enstatite chondrite interpretations

compositional diversity and geologic insights of the aristarchus crater from moon mineralogy mapper data 1 the moon mineralogy mapper m3 acquired high spatial and spectral resolution data of the aristarchus plateau with 140 m pixel in 85 spectral bands from 0 43 to 3 0 m the data were collected as radiance and converted to reflectance using the observational constraints and a solar spectrum scaled to the moon sun distance summary spectral parameters for the area of mafic silicate 1 and 2 m bands were calculated from the m3 data and used to map the distribution of key units that were then analyzed in detail with the spectral data this analysis focuses on five key compositional units in the region 1 the central peaks are shown to be strongly enriched in feldspar and are likely from the upper plagioclase rich crust of the moon 2 the impact melt is compositionally diverse with clear signatures of feldspathic crust olivine and glass 3 the crater walls and ejecta show a high degree of spatial heterogeneity and evidence for massive breccia blocks 4 olivine strongly concentrated on the rim wall and exterior of the southeastern quadrant of the crater is commonly associated the impact melt 5 there are at least two types of glass deposits observed pyroclastic glass and impact glass

the mineralogy of late stage lunar volcanism as observed by the moon mineralogy mapper on chandrayaan 1 1 the last major phases of lunar volcanism produced spectrally unique high titanium basalts on the western nearside of the moon the moon mineralogy mapper m3 on chandrayaan 1 has provided detailed measurements of these basalts at spatial and spectral resolutions necessary for mineralogical interpretation and mapping of distinct compositional units the m3 imaging spectrometer acquired data in 85 spectral bands from 430 to 3000 nm at 140 to 280 m pixel in its global mapping mode during the first half of 2009 reflectance data of several key sites in the western maria were also acquired at higher spatial and spectral resolutions using m3 s target mode prior to the end of the chandrayaan 1 mission these new observations confirm that both fresh craters and mare soils within the western high ti basalts display strong 1 m and weak 2 m absorptions consistent with olivine rich basaltic compositions the inferred abundance of olivine is observed to correlate with stratigraphic sequence across different mare regions and absolute ages the apparent stratigraphic evolution and fe rich compositions of these basalts as a whole suggest an origin from evolved residual melts rather than through the assimilation of more primitive olivine rich sources mare deposits with spectral properties similar to these late stage high ti basalts appear to be very limited outside the procellarum imbrium region of the moon and where present appear to occur as small areas of late stage regional volcanism detailed analyses of these new data and supporting measurements are in progress to provide further constraints on the mineralogy olivine abundance and compositions of these final products of lunar volcanism and the nature and evolution of their source regions