a new data reduction approach for the clementine nir data set application to aristillus aristarchus and kepler the clementine spacecraft launched in january 1994 has performed a nearly global surface mapping of the moon in eleven broad spectral bands at a resolution of 200 m the uv visible uv vis camera performed observations in five bands ranging from 0 415 to 1 0 m while the near infrared camera nir acquired data in six spectral bands ranging from 1 1 to 2 78 m uv vis images are calibrated to 4 the calibrated nir data set is yet to be finalized due to instrumental problems independently of the calibration effort for the full data set which is under the responsibility of the pi team we present here the first results of a heuristic approach to extract mineralogical information from raw images in regions of particular interest we processed images of craters aristillus aristarchus and kepler we computed band ratios using 0 75 0 9 0 95 1 0 1 1 1 25 1 5 and 2 0 m images to map the compositional heterogeneity and to discriminate between pyroxene olivine or feldspar rich areas absolute reflectance spectra have been derived using telescopic spectra as ground truth high orthopyroxene and clinopyroxene contents have been detected and spatially mapped on aristillus our results are in good agreement with previous studies in the case of aristarchus and show additional details due to the improved registration two regions exhibit spectra consistent with a high proportion of olivine with 25 pyroxene the rim of kepler exhibits a strong feature at 2 m correlated with the 1 m feature suggesting either a high orthopyroxene content or a very immature soil our method could be of interest for further investigations of the lunar surface using clementine nir data

lunar surface aluminum and iron concentration from galileo solid state imaging data and the mixing of mare and highland materials apollo x ray spectrometer data provide chemical information for 9 of the lunar surface galileo solid state imaging system ssi multispectral data for the moon are employed to reexamine the long accepted positive correlation between lunar surface reflectance or albedo and aluminum concentration derived from apollo x ray spectrometer data the overall goal of the analysis is to quantify the relationship between reflectance and aluminum and to take advantage of the extensive spatial coverage of the ssi data 75 of the lunar surface to calculate aluminum concentration from ssi reflectance for the majority of the lunar surface after removing nonmature highlands from the analysis it is found that the relationship between lunar surface reflectance and x ray spectrometer derived aluminum concentration is described by two diffuse endmembers representing highland and mare materials and an apparent mixing line suggestive of mixtures of mare and highland materials regression analysis is utilized to show that whereas the correlation between reflectance and aluminum for the entire lunar soil system is fairly good the correlations for mare soils alone and for highland soils alone are extremely low the low precision of the x ray data may at least in part be responsible for the observed poor correlations although the low correlation for the individual soil types precludes the precise calculation of aluminum concentration from reflectance approximate aluminum contents can be determined the excellent inverse correlation between aluminum and iron concentration for returned lunar soils allows an estimation of iron content to be made as well an extensive zone of mixtures of mare and highland soils exists in the vicinity of mare filled impact basins and around smaller craters this zone occurs in morphologically defined mare and highland units physical mixing of more mafic and less mafic material due to vertical and lateral transport by impact and downslope movement can account for the widespread mixing zones

space weathering on airless bodies resolving a mystery with lunar samples using new techniques to examine the products of space weathering of lunar soils we demonstrate that nanophase reduced iron npfe0 is produced on the surface of grains by a combination of vapor deposition and irradiation effects the optical properties of soils both measured and modeled are shown to be highly dependent on the cumulative amount of npfe0 which varies with different starting materials and the energetics of different parts of the solar system the measured properties of intermediate albedo asteroids the abundant s type asteroids in particular are shown to directly mimic the effects predicted for small amounts of npfe0 on grains of an ordinary chondrite regolith this measurement and characterization of space weathering products seems to remove a final obstacle hindering a link between the abundant ordinary chondrite meteorites and common asteroids

model near infrared optical constants of olivine and pyroxene as a function of iron content the imaginary coefficients of the complex index of refraction of olivine low ca orthopyroxene and high ca clinopyroxene are derived as a function of iron content and wavelength over the spectral region 0 4 to 2 5 m from reflectance spectra of powders and hapke radiative transfer theory reflectance spectra as a function of composition and grain size are computed and compared i find that while spectral effects of variations in these parameters are similar they are distinguishable variations in iron content do not explain all the observed spectral variations in the spectra of the samples investigated

evidence for critical level filtering of atmospheric gravity waves radiosonde measurements were used to investigate gravity wave activity within the lower stratosphere above the canadian high arctic the sondes were launched from the weather station at eureka 80 n 86 w on ellesmere island gravity waves were detected by the fluctuations they induced in temperature and the associated perturbation potential energy density was used to gauge the amount of wave activity it was found that over a 15 month period there were isolated episodes of enhanced wave activity rather than any distinct seasonal cycle profiles of wind velocity were also measured and used here to show that periods of high wave activity occurred only when there would be no or very little critical level filtering of the stationary waves generated by flow over the rough terrain in the vicinity of eureka it was also found that the potential energy spectral density was enhanced at all resolvable scales during the periods of high wave activity

space weathering from mercury to the asteroid belt the variety of evidence bearing on the nature of space weathering is reviewed the effects of space weathering include spectral darkening reddening and subdued absorption bands and the distinctive magnetic electron spin resonance caused by single domain metallic iron particles ever since the apollo missions two paradigms have dominated the thinking of the planetary science community concerning space weathering 1 the optical effects are caused by impact vitrified glass in agglutinates and 2 the submicroscopic metallic iron results from the reduction of ferrous iron by the impact melting of minerals whose surfaces have been saturated with hydrogen from the solar wind however studies carried out since the apollo program showed that both of these paradigms are invalid a hypothesis first suggested by the author and his colleagues 26 years ago but not generally accepted at that time now appears to be essentially correct both the optical and magnetic effects are caused by metallic iron particles smaller than the wavelength in ubiquitous vapor deposited coatings on soil particle surfaces and inside agglutinates the vapor is generated by both solar wind sputtering and micrometeorite impact vaporization and injected preferentially downward into the porous regolith the iron is reduced by a physical process the selective loss of oxygen that occurs during deposition of the vapor and does not require heating melting or a reducing environment a mathematical theory that describes the optical effects of the submicroscopic iron quantitatively is derived and applied to the regoliths of the moon mercury and an s asteroid

mapping the feo and tio2 content of the lunar surface with multispectral imagery the derivation of quantitative elemental concentrations from multispectral imaging of the moon has long been a goal of lunar remote sensing concentration maps at the spatial resolutions available from the recent clementine mission would provide a revolutionary new tool for understanding the origin and evolution of the lunar crust lucey et al 1995 presented a method for extracting the concentration of fe from multispectral imaging of the moon this paper examines and quantifies important aspects ofthat technique left unexamined by lucey et al which had the potential to severely limit its utility these aspects include the effects of maturity grain size mineralogy shading due to topography and the presence of glass we also present a new algorithm for derivation of tio2 from multispectral imaging of both mare and highland units we find that both techniques are only weakly sensitive to maturity and that they have about 1 wt accuracy based on examination of the spectral properties and compositions of resolved lunar sampling stations presented by blewett et al 1997 we also discuss these findings in the context of two contrasting views of the effect of composition on lunar spectral properties presented by pieters and coworkers and hapke and coworkers we find the view of hapke and coworkers to be more consistent with our observations using a global mosaic of clementine multispectral data and these element derivation algorithms we find that the global modal abundance of feo is 4 5 wt 1 wt and the global modal abundance of tio2 is 0 45 wt 1 wt

lunar iron and optical maturity mapping results from partial least squares modeling of chang e 1 iim data abstract iron and optical maturity omat are two key geological marks of the moon that closely related to its geochemical evolution and interactions between surface and space environment we apply partial least squares pls regression to chang e 1 imaging interferometer iim 32 bands between 480 and 960 nm in mapping lunar global feo and omat and the feo and omat values are derived based on reasonable spectral parameters absorbance band ratios tio 2 and maturity sensitive parameters etc after been calibrated by the feo map from lunar prospector gamma ray spectrometer lp grs the global feo map derived from pls modeling shows a quantitatively more reasonable result consistent with previous remote sensing results lp as well as lunar feldspathic meteorite studies and chang e 3 landing site based on the new feo map by chang e 1 we discover a compositional inhomogeneity across lunar highland regions which has not been suggested by previous datasets e g clementine uvvis furthermore we suggest that at least part of the feo enrichments in highlands would be caused by mixing of highland and mare materials the iim derived omat map does not suggest a dichotomy of the lunar highlands and mare regions implying the compositional differences between those two terrains have been suppressed we further check the maturity effect for the young mare basalts 2 show a linear decrease with ages 2 units with ultrahigh feo 20 wt and ultrahigh tio 2 10 wt tend to have greater omat values and vary little with ages 3 this may be due to the distinct optical maturity effects of ultramafic minerals i e ultrahigh fe and ti and or the spectral blue shifts of abundant ilmenite

radiative transfer modeling of lunar highlands spectral classes and relationship to lunar samples 1 tompkins and pieters 1999 identified eleven spectral classes present on the surface of the moon here we model these spectral classes to determine the compositions that define them we do this by mathematically matching spectral classes to radiative transfer computed spectra using spectral shape contrast and excursion parameters as defining characteristics model spectra are based upon known mineralogies mafic mineral mg s molar mg mg fe 100 and maturities we compare these compositional results to a compilation of 100 apollo samples to determine plausible representative samples for these spectra results indicate that unique mineralogic solutions for several spectral classes can be determined unambiguously however classes previously interpreted to be pyroxene rich are compositionally ambiguous results suggest these ambiguous mineral assemblages are not random but correlate with variations in absolute reflectance these data further suggest absolute reflectance is a compositionally diagnostic spectral parameter that should be used in conjunction with relative reflectance analysis to constrain mineralogy although absolute reflectance for the eleven spectral classes is not available to constrain their composition we detail mineral chemical i e mg and absolute reflectance variations of matching model relative reflectance spectra to narrow the possibilities this information is used in a pilot study of bullialdus crater for which clementine absolute reflectance is known results indicate bullialdus s central peak consists of tompkins and pieters spectral classes an agn and n bullialdus s spectra that match class n are roughly consistent with previous compositional interpretations however matches to classes an and agn indicate more mafic assemblages typical of mg suite norite gabbronorite rocks

lunar fe and ti abundances comparison of lunar prospector and clementine data the lunar prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of clementine spectral reflectance data with the iron and titanium dependence removed the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium incompatible rare earth elements that are enriched in the final phases of magma crystallization these regions are found mainly around the ramparts of the imbrium impact basin but not around the other basins including the much larger and deeper south pole aitken basin this result confirms the compositional uniqueness of the surface and interior of the imbrium region

calculating iron contents of lunar highland materials surrounding tycho crater from integrated clementine uv visible and near infrared data 1 optical properties of lunar surface materials are modified by exposure to the space environment including bombardment by solar wind particles and micrometeorites one of the main problems in the interpretation of lunar spectral observations is to separate the effects of exposure space weathering and those due to the composition of the soils mainly iron and titanium content here we use clementine near infrared nir data to investigate this problem for highland type soils in the tycho crater area our approach is based on the methods developed for an analysis of a mare region near aristarchus plateau le mouelic et al 2000 we show that the systematic relationships between spectral parameters 1 m band depth and continuum slope which were previously observed in a mare area with varying maturity degree are also valid for highland type soils this technique aimed at evaluating the iron content of the surface materials from clementine uv visible uvvis and near infrared data can therefore be applied globally this approach complements the widely used method of lucey and coworkers which relies on the uv visible bands only the proposed method relies mostly on band ratios the iron map produced from this method is therefore less dependent on topography than the iron estimates obtained with uv visible data alone where brightness is one of the controlling parameters therefore the proposed approach should be particularly useful at middle to high latitudes where local topography generates large variations in brightness and therefore hampers the interpretation of iron maps produced from uv visible bands only

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

clementine uvvis multispectral data and the apollo 17 landing site what can we tell and how well multispectral data obtained by the clementine mission are correlated to compositional and petrographic information for individual sample stations at the apollo 17 landing site the soils contain a variety of fe2 bearing phases in different proportions including low and high ca pyroxene olivine ilmenite and glass in the mare soils ilmenite carries a substantial proportion of the fe2 and in all soils glasses particularly agglutinates carry nearly as much or more fe2 as the silicates using an empirical calibration concentrations of feo and tio2 estimated from the ultraviolet visible uvvis data correlate well with measured compositions of surface soils yielding correlation coefficients of 0 94 and 0 95 respectively the ferrous absorption however is weak in the mostly submature to mature apollo 17 soils thus spectral curvature is useful only for investigating the mafic silicate mineralogy around fresh craters and deposits the effects of local topography cause significant variations in feo and tio2 derived from clementine uvvis data but do not impair first order geologic interpretations parameters derived from the uvvis data allow quantification of the composition and nature of the soils and by inference underlying rock formations and are consistent with the known geologic character of the landing site the highland regions along this part of the serenitatis rim are relatively feo rich partly as a result of abundant mafic impact melt breccia and partly from the addition of basaltic material in the form of impact debris and pyroclastic deposits at high elevations massif soils are rich in a mafic melt breccia component although slopes and areas mixed by small craters reveal a mixture of melt breccia and older highland material of anorthositic norite composition soils developed on hummocky deposits that postdate the massifs such as the sculptured hills have a similar range of compositions as the massifs elevated plains northeast of the sculptured hills are more mafic than the known impact melt breccias suggesting that they may also contain an older volcanic component sources of low ti basalt or very low ti basalt though not present in the immediate vicinity of the landing site occur east and northeast of taurus littrow valley and are readily identified using the uvvis data

composition and exposure age of the apollo 16 cayley and descartes regions from clementine data normalizing the optical effects of space weathering in order to quantitatively assess the composition of the lunar surface from reflectance spectroscopy it is necessary to be able to differentiate between the optical effects due to composition and those due to exposure to space weathering processes laboratory analyses of returned lunar soils are used to show that limited quantitative compositional information and the exposure age of the lunar surface can be determined using straightforward calculations from remotely acquired reflectance data sampled with a small number of spectral channels exposure age approximated by is feo where is is the characteristic ferromagnetic signal from single domain iron metal is estimated using a ratio of the reflectance at a wavelength outside of the 1 m ferrous iron absorption band to the reflectance at a wavelength within the band the iron plus titanium content of a soil can then be calculated from its is feo and reflectance these combined techniques are applied to clementine uvvis multispectral data of the lunar highlands in the vicinity of the apollo 16 landing site the is feo and feo tio2 contents are calculated for this region materials associated with recently formed impact craters and recent and or ongoing downslope movement are easily detected as nonmature the feo tio2 content of the descartes mountains is found to be 1 2 wt less than the cayley plains west of the apollo 16 landing site localized areas of compositional heterogeneity associated with some small impact events are also revealed a model for normalizing the optical contribution due to exposure to space weathering processes is applied to the clementine uvvis data in order to bring the data to an equivalent mature exposure state this approach allows residual spectral differences between the observed materials to be confidently interpreted as being due to compositional differences alone rather than to differences both of composition and of exposure the exposure normalized data reveal that this region of the highlands is characterized by limited large scale compositional heterogeneity that is detectable by a small number of spectral bandpasses the descartes mountains are identified as being more anorthositic than the cayley plains units most small impacts in the region excavated material compositionally similar to material surrounding them with the notable exceptions of the impacts that created south ray crater and an unnamed crater on the floor of abulfeda

discrimination between maturity and composition of lunar soils from integrated clementine uv visible near infrared data application to the aristarchus plateau the reflectance spectrum of a lunar soil is mainly dominated by the composition and the degree of exposure to space weathering processes such as micrometeorite bombardment and solar wind implantation the spectral alteration effects of space weathering should be removed for accurately investigating the composition of the lunar surface using remote sensing data in this paper we show that the integration of the clementine uv visible uvvis and near infrared nir channels provides an improved evaluation of the spectral alteration the depth of the mafic absorption feature at 0 95 m is also better defined by combining the uvvis and nir data laboratory spectra of lunar soil samples indicate that the continuum slope derived from the 1500 750 nm ratio is closely related to the concentration of fine grained submicroscopic iron is the continuum slope therefore provides an evaluation of the spectral alteration of the surface which can be subtracted from the 1 or 2 m absorption band depths to retrieve compositional information this method has been applied to the aristarchus plateau which exhibits a broad range of mineralogical composition and maturity a nine channel multispectral mosaic of 680 clementine images of the aristarchus plateau has been processed eight telescopic spectra have been used to check the validity of the reduction process for the near infrared bands the 1 m absorption band once corrected for spectral alteration provides an evaluation of the initial feo content in mafic silicates mafic iron lunar soil samples show that it is possible to quantitatively map mafic iron with this technique our results are in good agreement with those obtained using the algorithm of lucey et al 1995 1998a which is based on uvvis bands alone the mafic iron content and total iron content which can be derived from the combined uvvis and nir data sets are less sensitive to local slopes than that derived from lucey et al s method this new method could therefore be useful for investigating areas at middle to high latitudes removing spectral alteration from the 2000 1500 nm ratio also makes possible a better discrimination between olivine and pyroxene within identified mare basalts on the aristarchus plateau

analysis of lunar pyroclastic deposit feo abundances by lro diviner 1 thermal infrared reflectance spectra of rock forming minerals include a prominent minimum near 8 m known as the christiansen feature cf the inflection point wavelength is sensitive to the degree of polymerization of silicates which is strongly influenced by major cations notably iron in the minerals laboratory spectra of lunar soils demonstrate that the cf location is closely correlated to the sample s bulk feo abundance across the full range of apollo soil samples including pyroclastic glass this correlation is the basis for estimating lunar surface feo abundances using orbital thermal infrared measurements the diviner lunar radiometer experiment on the lunar reconnaissance orbiter includes three thermal infrared channels selected to determine the cf positions for sites across the lunar surface diviner measurements are used to derive feo abundances in the aristarchus sulpicius gallus and rima fresnel pyroclastic deposits the calculated feo abundances for aristarchus and sulpicius gallus lie within the compositional range of feo rich pyroclastic glasses but outside the range of most mare soils supporting the interpretations of these deposits as glass rich the calculated feo abundance for the rima fresnel deposit is close to that of mare soils supporting a contention that this deposit is dominated by basaltic fragments rather than glass the diviner measurements hold the potential to determine feo abundances in many lunar pyroclastic deposits a better understanding of these compositions will provide insight into the magmatic history and composition of the lunar interior as well as an enhanced inventory of potential resources for future human exploration

optical effects of space weathering the role of the finest fraction the optical properties of lunar softs are different than those of rocks from which they are derived as a consequence of lunar space weathering soils are darker and exhibit a distinctive red sloped continuum and weaker mineral absorption bands the accumulation of dark glass welded aggregates agglutinates has been thought to account for these optical effects of space weathering on lunar soils spectroscopic analyses of agglutinate separates and size fractions for a suite of lunar softs presented here indicate that the agglutinate paradigm is insufficient to fully account for lunar optical alteration it is the finest fraction of lunar soils 25 gm which constitute 25 wt that dominates the optical properties of the bulk soil unlike size fractions of most silicates for which the finest fraction is the brightest the lunar soil size fractions all have comparable albedos in the short wavelength visible in the near infrared however it is the finest fraction that exhibits the steep red continuum and weak absorption bands the properties of the finest fraction cannot be duplicated by preparing a fine fraction by grinding larger agglutinate rich soil particles these results suggest space weathering on airless bodies is dominated by surface correlated processes perhaps associated with the development of fine grained fe o on or near the surface of grains and the accumulation of the larger agglutinates is not necessarily required to account for lunar optical alteration

continental margin evolution of the northern arabian platform in syria copyright aapg 1993 reprinted by permission of the aapg whose permission is required for further use see also http atlas geo cornell edu syria best 1993 html

lunar iron and titanium abundance algorithms based on final processing of clementine ultraviolet visible images the clementine mission to the moon returned global imaging data collected by the ultraviolet visible uvvis camera this data set is now in a final state of calibration and a five band multispectral digital image model dim of the lunar surface will soon be available to the science community we have used observations of the lunar sample return sites and stations extracted from the final dim in conjunction with compositional information for returned lunar soils to revise our previously published algorithms for the spectral determination of the feo and tio2 content of the lunar surface the algorithms successfully normalize the effects of space weathering so that composition may be determined without regard to a surface s state of maturity these algorithms permit anyone with access to the standard archived dim to construct high spatial resolution maps of feo and tio2 abundance such maps will be of great utility in a variety of lunar geologic studies

clementine images of the lunar sample return stations refinement of feo and tio2 mapping techniques clementine uvvis images of the lunar sample return sites have been processed and used to produce refined calibrations for the iron and titanium determination algorithms of lucey et al 1995 1996 the high spatial resolution of the clementine data permits individual sampling stations to be resolved at the apollo 15 16 and 17 landing sites we find an excellent linear correlation between the spectral fe and ti parameters and the average feo and tio 2 contents of soils sampled at each site or station this correlation demonstrates that these techniques can confidently be applied to other areas of the moon the luna 24 site does not fit the ti relation found for other sites suggesting that either its sample is nonrepresentative or the reported landing coordinates are incorrect

composition of the lunar highland crust from near infrared spectroscopy near infrared reflectance spectra of the lunar highlands are synthesized to obtain global information about the composition of the lunar near side crust immature exposed surfaces from small fresh craters mountains and massifs and large craters with central peaks are included in a survey of rock types across the lunar near side compositions recognized in these data include anorthosite noritic gabbric and troctolitic mineral assemblages three quarters of the areas studied that represent samples from the upper 1 2 km of lunar crust exhibit noritic compositions with different amounts of pyroxene and or brecciation alteration norites are ubiquitous across the near side and show no spatial clustering associated with any of the major basins in contrast to this noritic megaregolith of the upper crust material representing stratigraphically deeper zones 5 15 km of the lunar crust is dominated by gabbros anorthosites and troctolites with less than a quarter of the areas studied exhibiting a noritic composition the origin of the noritic megaregolith and its relation to deeper crustal material is thus somewhat of an enigma the current limited statistics for areas identified as anorthosites and troctolites are insufficient to derive global spatial distributions gabbroic areas however are notably concentrated in the western hemisphere although incomplete for a global assessment of crustal materials these data demonstrate that the lunar near side crust is clearly mineralogically heterogeneous both laterally and vertically and not well mixed below 1 2 km