syenite associated disseminated gold deposits in the abitibi greenstone belt canada a distinct group of gold deposits in the abitibi greenstone belt is spatially associated with quartz monzonite to syenite stocks and dikes the deposits occur mainly along major fault zones in association with preserved slivers of alluvial fluvial timiskaming type sedimentary rocks the deposits consist of disseminated sulfide replacement zones with variably developed stockworks of quartz carbonate k feldspar veinlets within zones of carbonate albite k feldspar and sericite alteration the syenitic intrusions are broadly contemporaneous with deposition of timiskaming sedimentary rocks and together with disseminated gold mineralization they have been overprinted by subsequent regional folding and related penetrative cleavage disseminated gold orebodies occur within composite syenitic stocks or along their margins along satellite dikes and sills and along faults and lithologic contacts away from intrusions orebodies in these different positions are interpreted to represent proximal to distal components of large magmatic hydrothermal systems centered on and possibly genetically related to composite syenitic stocks

the influences of row grade ridge height and field slope on the seepage hydraulics of row sideslopes in contour ridge systems abstract seepage plays an important role in soil erosion in contour ridge systems seepage generated from subsurface flow causes hillslope instability by reducing the soil shear strength and mobilizing soil particles and can produce cave like features called seepage undercuts that can lead to contour failure as the main threat to contour plowing seepage results in large amounts of soil erosion due to row grade models used to predict seepage over a time series will provide a basis for modeling soil erosion resulting from seepage in contour ridging systems understanding seepage and its effects will advance our knowledge regarding seepage erosion mechanisms in contour ridge systems in this study 23 treatments were arranged using an orthogonal rotatable central composite design to model a seepage time series build a simple seepage prediction model and investigate the effects of row grade field slope and ridge height on seepage discharge most of the seepage discharge time series followed an s shaped curve the seepage discharge processes were fit by an exponential model with a determination coefficients r2 greater than 0 995 furthermore the physical meaning of the exponential model was consistent with the experimental results the seepage discharge continuously increased before the inflection point and then decreased finally the seepage discharge approached a steady value the maximum seepage discharge growth rate was achieved within 14 min and the seepage discharge became steady within 106 min second order polynomial regression models were used to determine the total and predicted steady seepage discharge using independent variables of row grade field slope and ridge height which produced r2 values of 0 66 p

infrared reflectance spectra 4 12 µm of typical lunar samples a laboratory study of the mid infrared spectral reflectance properties of typical apollo lunar rock and soil samples was conducted using a modern interferometric spectrometer the results show that characteristic spectral features exist in the 4 12 micrometer range that are diagnostic of rock composition and mineralogy especially for the plagioclase rich rocks and soils this is the first phase of a comprehensive infrared reflectance study underway to better understand the use of infrared emission spectroscopy for mapping the surface composition of the moon and other silicate bodies

response to comment on ascent of dinosaurs linked to an iridium anomaly at the triassic jurassic boundary our recent study on the nature of the ascent of the dinosaurs 1 1 argued three main points i that a major terrestrial tetrapod mass extinction is concentrated at the palynologically identified triassic jurassic boundary in eastern north america based on footprints and bones ii that

hydrothermal alteration within the basement of the sedimented ridge environment of middle valley northern juan de fuca ridge the middle valley segment at the northern end of the juan de fuca ridge is a deep extensional rift blanketed with 200 500 m of pleistocene turbiditic sediment sites 857 and 858 were drilled during ocean drilling program leg 139 to determine whether these two sites were hydrologically linked end members of an active hydrothermal circulation system site 858 was placed in an area of active hydrothermal discharge with fluids up to 270 c venting through anhydrite bearing mounds on top of altered sediment the shallow basement of fine grained basalt that underlies the vents at site 858 is interpreted as a seamount that was subsequently buried by turbidites site 857 was placed 1 6 km south of the site 858 vents in a zone of high heat flow and numerous seismically imaged ridge parallel faults drilling at site 857 encountered sediments that are increasingly altered with depth and that overlie a series of mafic sills at depths of 460 940 m below sea floor sill margins and adjacent baked sediment are highly altered to magnesian chlorite and crosscut with veins filled with quartz chlorite sulfides epidote and wairakite the sill interiors vary from slightly altered with unaltered plagioclase and clinopyroxene in a mesostasis replaced by chlorite to local zones of intense alteration and brecciation in these latter zones the sill interiors are pervasively replaced by chlorite epidote quartz pyrite titanite and rare actinolite the most complete replacement is associated with brecciated horizons with low recovery and slickensides on fracture surfaces which we interpret as intersections between faults and the sills geochemically the alteration of the sill complex is reflected in significant whole rock depletions in ca sr and na with corresponding enrichments in mg al and most metals the latter results from the formation of conspicuous sulfide poikiloblasts in contrast metamorphism of the site 858 seamount includes incomplete albitization of plagioclase phenocrysts and replacement of sparse mafic phenocrysts much of the basement alteration at site 858 is confined to crosscutting veins except for a highly altered and veined horizon at the contact between basaltic basement and the overlying sediment the sill complex at site 857 is more highly depleted in 18 o 18 o 2 4 4 7 and more pervasively replaced by secondary minerals relative to the extrusives at site 858 18 o 4 5 5 5 there is no evidence of significant albitization of the plagioclase at site 857 suggesting high ca na in the pore fluids fluid inclusion data from hydrothermal minerals in altered mafic rocks and veins at sites 857 and 858 show a consistency of homogenization temperatures varying from 245 to 270 c which is within the range of temperatures observed for the fluids venting at site 858 the consistency of the fluid inclusion temperatures the lack of albitization within the site 857 sills and the apparently low water rock ratio collectively suggest that the sill complex at site 857 is in thermal equilibrium and being altered by a highly evolved ca rich fluid similar to the fluids now venting at site 858 the alteration evident in these two deep crustal drillsites is a result of the ongoing hydrothermal circulation and is consistent with downhole logging results instrumented borehole results and hydrothermal fluid chemistry the pervasive alteration of the laterally extensive sill sediment complex at site 857 determines the chemistry of the fluids that are venting at site 858 the limited alteration of the site 858 lavas suggests that this basement edifice acts as a penetrator or ventilator for the regional hydrothermal reservoir with much of the flow focussed at the highly altered and veined sediment basalt contact

effects of rainfall intensity and slope gradient on the dynamics of interrill erosion during soil surface sealing abstract soil erosion during rainfall is strongly affected by runoff and slope steepness runoff production is drastically increased when a seal is formed at the soil surface during rainfall therefore a complex interaction exists between soil erosion and surface sealing in this study the dynamics of interrill erosion during seal formation is studied under different simulated rainfall and slope conditions a sandy soil was exposed to 70 mm of rainfall at two intensities 24 mm h 1 and 60 mm h 1 and five slope gradients from 5 to 25 infiltration runoff and soil loss rates were monitored during rainfall final infiltration rates increased with slope gradient at both rainfall intensities this effect being stronger for the higher intensity cumulative runoff at the end of the rainfall event was lower as slopes were steeper while an opposite trend was obtained for soil loss for the 5 and the 9 slopes the sediment concentration in runoff reached quickly a stable value during the whole rainfall event while it reached a peak value before declining for the higher slopes the peak value and its timing were rainfall intensity dependent soil erodibility during seal formation was evaluated using two empirical multiplication of factors type models it seems that slope and rainfall erosivity are accounted for only partly in these models for mild slope gradients below 9 the value of k i estimated by means of the two expressions becomes practically constant shortly after runoff apparition consequently the estimates resulting from this type of expressions remain valuable from the practical point of view

noise simulation and correction in synthetic airborne tir data for mineral quantification rock forming minerals such as feldspar and quartz can be identified and quantified from thermal infrared tir laboratory spectroscopy using spectral models this paper uses synthetic airborne tir spectra to test whether the hyperspectral spatially enhanced broadband array spectrograph system sebass would theoretically be able to detect quartz and feldspar minerals and quantitatively predict mineral modes in felsic igneous rocks data from a previous laboratory study were used to simulate tir spectra with band locations and noise levels of the sebass sensor the quantitative partial least squares regression plsr models from that study were applied to newly created synthetic sebass data and results were compared with the predictions from the previous study predicted compositions based on sebass band positions are nearly identical rho 0 995 to those based on laboratory resolution results are still reliable prediction errors within 0 4 absolute to the original laboratory plsr predictions when adding up to 1 noise about five times the sebass noise level to the synthetic data prediction errors rapidly increase when noise levels beyond 1 are used these results show that sebass spectral resolution spectral coverage and signal to noise levels are sufficient to quantitatively predict quartz and feldspar amounts and feldspar compositions with models based on plsr spectral distortions such as reduced spectral contrast tilts and vertical shifts must be compensated for before these quantitative models are applied a mean and standard deviation masd normalization is proposed using a set of ground data for compensating systematic errors that are common to all image pixels

the candelaria punta del cobre iron oxide cu au zn ag deposits chile several iron oxide rich cu au zn ag deposits define an approximately 5 km wide and at least 20 km long belt along the eastern margin of the coastal batholith near copiapo chile this belt includes the large candelaria mine and a group of middle and small sized mines in the punta del cobre district which is located about 3 km northeast of the candelaria deposit estimated geologic resources of the belt are on the order of 700 to 800 million metric tons mt at 1 0 percent cu the ore occurs in veins breccia and stringer bodies and in replacement bodies that are roughly concordant to bedding the orebodies are hosted mainly by volcanic and volcaniclastic rocks of the punta del cobre formation and in places also occur in volcaniclastic intercalations in the lower part of the overlying early cretaceous chanarcillo group most of the larger orebodies in the belt are located where northwest trending brittle faults intersect the contact between massive volcanic and volcaniclastic rocks these northwest faults and a major northeast trending ductile shear zone control portions of the ore of the candelaria deposit chalcopyrite is the only hypogene cu mineral the cu au ore is characterized by abundant magnetite and or hematite and by locally elevated concentrations of ag zn mo and light rare earth elements the ore is hosted mainly in zones with biotite potassium feldspar calcic amphibole epidote alteration at candelaria in the punta del cobre district ore in the deeper parts of the deposits is similarly associated whereas at shallow levels it occurs in zones of biotite potassium feldspar or albite chlorite calcite alteration mineralization at candelaria punta del cobre took place under relatively oxidized conditions manifested by the formation of specular hematite in parts of the district the pseudomorphic replacement of early specular hematite by magnetite during the main iron oxide formation marks a shift toward more reduced conditions or higher temperatures the bulk of the magnetite probably formed at temperatures of about 500 to 600 c the main sulfide stage followed with formation of pyrite and chalcopyrite at temperatures of 470 to 328 c subsequent martitization of the magnetite points to a temperature decrease cooling of the hydrothermal system is also indicated by the homogenization temperatures of 236 c of saline fluid inclusions in late stage calcite oxygen isotope combined with microthermometric data suggest that magmatic fluids or nonmagmatic fluids equilibrated with magmatic silicates were dominant during the main copper mineralization relatively light oxygen isotope signatures of fluids in equilibrium with late calcite suggest mixing with a nonmagmatic fluid e g basinal brines or meteoric waters during the late stages of hydrothermal activity sulfur isotope ratios of chalcopyrite pyrite pyrrhotite and sphalerite from the bronce candelaria las pintadas santos and socavon rampa deposits range from 34scdt values of 0 7 to 3 1 per mil this narrow range of sulfur isotope ratios near 0 per mil is consistent with sulfur of magmatic origin anhydrite from the candelaria mine paragenetically overlaps with chalcopyrite fluid inclusions in this anhydrite homogenize between 340 and 470 c and it has 34scdt values between 14 5 and 17 5 per mil a sulfate sulfide value of 13 4 per mil for a sample with coexisting anhydrite and chalcopyrite is consistent with sulfide sulfate fractionation at temperatures on the order of 400 c ore lead isotope signatures are homogeneous and similar to those of least altered volcanic host rocks and nearby intrusive rocks radiometric ages including new 40ar 39ar ages for hydrothermal alteration at candelaria point to a main cu au mineralization event at candelaria punta del cobre at around 115 ma the ages indicate that ore formation was broadly coeval with batholithic granitoid intrusions and with regional uplift they further imply that the cu au zn ag deposits formed at shallow crustal levels 3 km the stable isotope data the presence of previously reported hypersaline co2 rich fluid inclusions in the main cu ore stage and saline fluid inclusions in late stage calcite the oxidized character of the first ore fluid pulses and the mineralization age coeval with nearby intrusive activity are consistent with but not unequivocally evidence of magmatic fluid contribution into the hydrothermal system

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

thermal infrared reflectance and emission spectroscopy of quartzofeldspathic glasses 1 this investigation seeks to better understand the thermal infrared tir spectral characteristics of naturally occurring amorphous materials through laboratory synthesis and analysis of glasses because spectra of glass phases differ markedly from their mineral counterparts examination of glasses is important to accurately determine the composition of amorphous surface materials using remote sensing datasets quantitatively characterizing tir 5 25 m spectral changes that accompany structural changes between glasses and mineral crystals provides the means to understand natural glasses on earth and mars a suite of glasses with compositions analogous to common terrestrial volcanic glasses was created and analyzed using tir reflectance and emission techniques documented spectral characteristics provide a basis for comparison with tir spectra of other amorphous materials glasses clays etc our results provide the means to better detect and characterize glasses associated with terrestrial volcanoes as well as contribute toward understanding the nature of amorphous silicates detected on mars

results from the mars global surveyor thermal emission spectrometer the thermal emission spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase together with about a 35 percent dust component provides the best fit to the spectrum qualitative upper limits can be placed on the concentration of carbonates 10 percent olivine 10 percent clay minerals 20 percent and quartz 5 percent in the limited regions observed limb observations in the northern hemisphere reveal low lying dust hazes and detached water ice clouds at altitudes up to 55 kilometers at an aerocentric longitude of 224 degrees a major dust storm developed in the noachis terra region the south polar cap retreat was similar to that observed by viking

a global view of martian surface compositions from mgs tes thermal emission spectrometer tes data from the mars global surveyor mgs are used to determine compositions and distributions of martian low albedo regions two surface spectral signatures are identified from low albedo regions comparisons with spectra of terrestrial rock samples and deconvolution results indicate that the two compositions are a basaltic composition dominated by plagioclase feldspar and clinopyroxene and an andesitic composition dominated by plagioclase feldspar and volcanic glass the distribution of the two compositions is split roughly along the planetary dichotomy the basaltic composition is confined to older surfaces and the more silicic composition is concentrated in the younger northern plains

accuracy of plagioclase compositions from laboratory and mars spacecraft thermal emission spectra 1 plagioclase the most abundant mineral in many terrestrial and martian igneous rocks exhibits a range of compositions that reflects changing conditions during crystallization thermal emission spectrometers tes themis and mini tes on board mars spacecraft provide a means of determining average plagioclase compositions directly we demonstrate that spectrally modeled average plagioclase compositions in terrestrial basalts andesites and dacites correspond to measured values to within 10 6 an molar ca ca na 100 of weighted average values and 13 14 an of normative compositions analyses of spectra from two component plagioclase mixtures varied by volume and composition provide additional insight into potential effects of plagioclase zoning considering the variability in types of observed plagioclase zoning patterns in terrestrial volcanic rocks normal zoning calcic cores and sodic rims cannot be assumed and thus cannot account for an apparent sodic bias seen in previous spectrally modeled compositions this bias is better explained by higher abundances of sodic groundmass plagioclase relative to calcic phenocrysts deconvolution modeling of laboratory spectra of physical mixtures convolved to various instrument resolutions predicts that tes themis and mini tes spectra may be used to extract plagioclase compositions to within 9 12 an 11 12 an and 8 12 an respectively of measured values in coarse sand plagioclase mixtures with 1 standard deviations of 4 an for laboratory tes and mini tes resolutions and 6 an for themis resolution

quantifying total sulfide content of cores and cut rock surfaces using thermal infrared reflectance in this study core samples of sulfide rich zones were delineated from their host rock and a quantitative estimation of sulfide content on cut rock faces was made using thermal infrared reflectance tir 3 0 30 m region spectroscopy core sections and rocks were collected from mines in the sudbury basin ontario canada the tsc areal percentage of total sulfide content of each sample was then estimated by summing the modal abundance of all sulfide minerals chalcopyrite pyrrhotite and pentlandite tir at 1319 cm 1 tir1319 is linearly related to tsc the average of the spectral ratios tir995 tir1319 and tir1180 tir1319 tirratio is related exponentially to tsc the coefficients of determination r2 based on a calibration data set are 0 90 and 0 87 respectively two models were tested the tir1319 model and the tirindex model the latter combines tir1319 and tirratio the value for r2 for predicted tsc versus observed tsc from thin sections is 0 98 and 0 97 respectively with

the longwave infrared 3 14μm spectral properties of rock encrusting lichens based on laboratory spectra and airborne sebass imagery there has been a progressive emergence of airborne longwave spectral sensing capabilities e g spatially enhanced broadband array spectrograph system sebass of potential value for remote geological mapping in arctic and subarctic regions however the presence of rock encrusting lichens can obscure spectral features diagnostic of minerals this paper documents the longwave 3 14 m spectral transmittance and reflectance properties of rock encrusting lichens as determined from lichen samples from rock samples encrusted with lichens and observations from airborne sebass imagery the samples and sebass airborne hyperspectral imagery were acquired over the 1 9 ga cape smith greenstone belt of northern quebec within the restrahlen region 8 12 m where silicate minerals display peaks in reflectance the maximum reflectance observed for rock encrusting lichens is 1 6 these lichens display low reflectance and spectral contrast and approach a blackbody behavior for lichens detached from the rock substrate spectra obtained on two backgrounds of contrasting reflectance are similar 0 75 difference in reflectance indicating that lichens transmit little or no light detailed observations reveal three features that can be attributed to organic compounds in lichens 3 41 6 58 8 13 m the feature located near 8 13 m is a reflectance peak within the restrahlen region of enhanced mineral reflectance a measure of the strength of this feature and the mean reflectance in the restrahlen region for laboratory data and sebass imagery reveals linear mixing trajectories between a lichen endmember and a suite of geological endmembers this data representation enables the visualization of mixing lines the delineation of geologically informative endmembers and provides a means to mask pixels in imagery that encompass the greatest abundance of rock encrusting lichens therefore facilitating geological mapping the implications for the detection of geological endmembers and mapping are discussed

impact of glacier changes on ecosystem of proglacial lakes in high mountain regions of east siberia russia mountain lakes in east siberia have been studied for recent changes in water chemistry turbidity and diatom assemblages preserved in bottom sediments we performed a regional analysis of the relative effect of climate and glacier changes on change in diatom diversity and supply of meltware in proglacial lakes we analysed sediment records from east siberian glacier lakes using geochemical and diatoms proxies we found that dramatic changes in communities and abundance of diatoms and biogenic proxy could be induced by low nutrient concentrations in glacial lakes and high turbidity due to active degradation of glaciers and snow patches as a result of the global increase in temperature in the northern hemisphere our evidences show that diatoms have been gradually decreased since ca the 1880s a significant tendency towards diatom reducing occurred at high summer regional temperatures this tendency may be attributed to the fact that glaciers and snow patches thawed actively in east siberia during ca 1880 1958 which was induced by the beginning of the recent warming ca 1850 1860 and a long period of relatively warm regional climate from ca 1900 to 1960

soil erosion processes and sediment sorting associated with transport mechanisms on steep slopes summary sediment size distribution greatly affects sediment transport and deposition a better understanding of sediment sorting will improve understanding of erosion and sedimentation processes which in turn will improve erosion modeling to address this issue a total of 12 rainfall simulation experiments were conducted in a 1 m by 5 m box with varying steep slopes 10 15 20 and 25 and the simulated rainfall lasted for 1 h at a rate of 90 mm h 1 for each simulated event runoff and sediment were sampled at 3 min intervals which were performed to study in detail the temporal change in size distribution of the eroded materials these data were used to interpret the real time sequence of transport mechanisms acting in response to the simulated rainfall total soil loss is the sum of suspended saltating and contact loads the proportion of sediment r 2 0 452 p n 120 suspension saltation transports the finer than 0 054 mm size sediment was the most important erosion mechanism during interrill erosion processes however after rill development on hillslopes bed load transport by rolling of medium to large sized sediment particles coarser than 0 152 mm became an increasingly important transport mechanism and it were also enhanced by increased slope overall the study supports a strong relationship between the sediment transport of contact rolling load and stream power the partition of soil loss into these more meaningful components appears to be essential both for initial data interpretation and for subsequent use of such data for soil loss prediction

a rational method for estimating erodibility and critical shear stress of an eroding rill abstract soil erodibility and critical shear stress are two of the most important parameters for physically based soil erosion modeling to aid in future soil erosion modeling a rational method for determining the soil erodibility and critical shear stress of rill erosion under concentrated flow is advanced in this paper the method suggests that a well defined rill be used for shear stress estimation while infinite short rill lengths be used for determination of detachment capacity the derivative of the functional relationship between sediment yield and rill length at the inlet of rill flow as opposed to average detachment rate of a long rill was used for the determination of detachment capacity soil erodibility and critical shear stress were then regressively estimated with detachment capacity data under different flow regimes laboratory data of rill erosion under well defined rill channels from a loess soil was used to estimate the soil erodibility and critical shear stress the results showed that no significant change in soil erodibility k r was observed for different slope gradients ranging from 5 to 25 while critical shear stress increased slightly with the slope gradient soil erodibility of the loess soil was 0 3211 0 001 s m 1 the soil erodibility and critical shear stress calculations were then compared with data from other resources to verify the feasibility of the method data comparison showed that the method advanced is a physically logical and feasible method to calculate the soil erodibility and critical shear stress for physically based soil erosion models

estimation of the detachment rate in eroding rills in flume experiments using an ree tracing method abstract rill erosion can be a serious problem on cultivated slopes understanding the mechanisms of the detachment process in eroding rills is important in developing and improving process based erosion prediction models the detachment rate defined as the sediment amount detached from a unit area in a unit time is a crucial parameter in most physical erosion prediction models most current studies on rill detachment rates use spatially averaged soil erosion data which provides little information about soil erosion dynamics due to the lack of spatially distributed contemporaneous rill erosion data the objective of this study was to estimate the net detachment rate in eroding rills using a rare earth element ree tracing method flume experiments were conducted with ten ree oxides ho 2 o 3 tb 4 o 7 eu 2 o 3 yb 2 o 3 dy 2 o 3 sm 2 o 3 la 2 o 3 tm 2 o 3 ceo 2 and nd 2 o 3 as tracers mixed with soil in different sections of five slopes 8 74 17 62 26 78 36 38 and 46 6 exposed to three water flow rates 2 4 and 8 l min 1 regulated water flow was introduced to the upper end of flumes 8 m long and 0 1 m wide which were divided into 10 equal segments each containing a different ree soil mixture the net detachment rate from each rill segment was calculated from the ree concentrations in the eroded and transported material the detachment rates from different segments along the rills at different slope gradients and flow rates were compared with those estimated directly from previous studies and were found to increase with increasing slope gradient and flow rate results also showed that the net rill detachment rates decreased linearly with an increase in sediment concentration and decreased exponentially with an increase in rill length the ree derived detachment data and their relationship with sediment concentrations are consistent with the detachment function used in the wepp model and are helpful in understanding the processes of rill erosion using rees to trace detachment rates in continuous rills is a valid and advantageous technique for estimating the spatial distribution of the rill detachment rates

surface mineral mapping at steamboat springs nevada usa with multi wavelength thermal infrared images abstract the purpose of this study was to evaluate the use of airborne multispectral and hyperspectral thermal infrared tir image data for mapping surface minerals characteristic of active geothermal systems tir image data from the master multispectral spectrometer and the sebass hyperspectral spectrometer were acquired over steamboat springs nevada usa in september 1999 spectral emissivity information was extracted from the data and used to generate mineral maps using the master data it was possible to map the extent of the active geothermal area as well as silica rich vs clay rich areas using the sebass data the same areas could be mapped and additionally the presence of several minerals including opal quartz alunite anorthite albite and kaolinite could be identified the sebass data also detected previously unidentified hydrous sulfate minerals tamarugite and alunogen forming around active fumaroles laboratory spectral data and xrd analyses of field samples confirmed the dominant mineral phases identified remotely the airborne field and laboratory data together with temperature anomaly and fumarole location data from other studies were synthesized and linked to the surface geology to determine the diagnostic surface mineral expression that could be mapped with tir remotely sensed data for future exploration for similar geothermal systems opaline sinter deposits are the most diagnostic surface expression of hot spring activity at steamboat springs because they represent areas of the recent geyser activity the differentiation between opal and chalcedony deposits and the identification of hydrous sulfate minerals forming around active fumaroles are also important because chalcedony represents ancient sinter deposits and hydrous sulfate minerals indicate locations of fumaroles that may be venting diffusely with no geyser activity the surface expression of the geothermal system at steamboat springs is small which emphasizes the need for high spatial resolution airborne imagers the 90 m pixels of aster tir data over the same area were only capable of resolving the area of past and recent sinter deposits together master multispectral tir data covered the entire area 12 km 2 at 5 m spatial resolution and were capable of defining the extent of the sinter deposits and zones of hydrothermally altered rocks the sebass image swath was too narrow 256 m to add significant spatial information to the overall map but the high spectral content identified several important minerals related to the local geology and the mineralogic surface expression of the geothermal system

spectral evidence for weathered basalt as an alternative to andesite in the northern lowlands of mars mineral abundances derived from the analysis of remotely sensed thermal emission data from mars have been interpreted to indicate that the surface is composed of basalt surface type 1 and andesite surface type 2 1 the global distribution of these rock types is divided roughly along the planetary dichotomy which separates ancient heavily cratered crust in the southern hemisphere basalt from younger lowland plains in the north andesite 1 but the existence of such a large volume of andesite is difficult to reconcile with our present understanding of the geological evolution of mars here we reinterpret martian surface rock lithologies using mineral abundances from previous work1 and new mineralogies derived from a spectral end member set representing minerals common in unaltered and low temperature aqueously altered basalts our results continue to indicate the dominance of unaltered basalt in the southern highlands but reveal that the northern lowlands can be interpreted as weathered basalt as an alternative to andesite the coincidence between locations of such altered basalt and a suggested northern ocean basin implies that lowland plains material may be composed of basalts weathered under submarine conditions or weathered basaltic sediments transported into this depocentre

using fourier transform infrared spectroscopy to determine mineral phases in sediments abstract in paleoenvironmental studies the mineralogical composition of sediments is an important indicator in combination with other indicators they contribute to the understanding of changes in sediment sourcing as well as in weathering and depositional processes fourier transform infrared spectroscopy ftirs spectra contain information on mineralogical composition because each mineral has a unique absorption pattern in the mid ir range although easily obtained ftir spectra are often too complex to infer mineral concentrations directly in this study we use a calibration set of ca 200 sediment samples conventionally measured using x ray diffraction xrd in order to develop multivariate partial least squares pls regression models relating mineral contents to sediment spectra good correlations were obtained for the most common minerals e g quartz k feldspar illite plagioclase smectite calcite correlation coefficients ranged from 0 85 to 0 92 coefficients for the validation varied from 0 64 to 0 80 the number of latent variables pls regression components in the models ranged between 3 and 7 and the range of variation of the rmsecv gradient was from 15 28 to 5 7

interrill erosion from disturbed and undisturbed samples in relation to topsoil aggregate stability in red soils from subtropical china abstract the assessment of soil erodibility to water erosion in the field is often expensive and time consuming this study was designed to reveal the effects of aggregate breakdown mechanisms on interrill erosion dynamics and develop an improved model for assessing interrill soil loss which incorporated the soil aggregate stability tests as a substitute for the interrill erodibility parameter from both disturbed and undisturbed samples for red soils in subtropical china six cultivated areas of sloping land with red soils were selected and topsoil aggregate stability was analyzed using the le bissonnais method to determine the different disaggregation forces laboratory rainfall simulations were designed to distinguish the effects of slaking at different wetting rates and mechanical breakdown with and without screening on soil erosion characteristics field rainstorm simulations with medium and high rainfall intensities were conducted on runoff plots 2 m 1 m with slope gradients varying from 10 to 20 for each soil type a new instability index ka which considers aggregate breakdown mechanisms in interrill erosion processes was proposed based on the disturbed sample results ka showed a close relationship with erosion rates in both disturbed and undisturbed samples following from the results of undisturbed sample experiments ka was used as a substitute for the erodibility factor and introduced into the wepp model establishing a new erosion predication formula for red soils which had a good correlation coefficient r 2 0 89 this research made a good attempt at estimating the interrill erosion rate on the basis of aggregate stability from simple laboratory determinations these results extend the validity of soil aggregation characterization as an appropriate indicator of soil susceptibility to interrill erosion in red soils from subtropical china the formula based on the instability index ka has the potential to improve the methodology used for assessing interrill erosion rates

quartzose mafic spectral feature space model a methodology for extracting felsic rocks with aster thermal infrared radiance data abstract the original spectral features of felsic rocks are often intermingled with other surface objects which results in difficulty of detecting felsic rocks using remote sensing techniques few felsic rock indices were proposed and visual interpretation with rgb false color composition is widely used to detect felsic rocks this paper aims to construct a two dimensional spectral feature space model to extract felsic rocks using aster thermal infrared radiance data the study area is located in northern qinghai province western china with average altitude of approximately 4200 m a large number of training pixels of mafic ultramafic rock quartz rich rock felsic rock carbonate rock and vegetation were selected from the aster images as samples of these surface objects then we used a quartz rich rock index qi qi band14 0 844 band12 1 897 and a mafic ultramafic rock index mi mi 0 915 band10 band13 1 437 to generate a two dimensional scatter plot the plot was named after quartzose mafic spectral feature space qmfs the samples show an approximate triangular shape in the qmfs mafic ultramafic rock quartz rich rock and carbonate rock are located in separate locations in the three vertex regions respectively while felsic rock is located in the central region of the triangle next we calculated a linear belt of silicate rocks in which silicate rocks vary regularly by using a linear regression analysis in the qmfs statistical characteristics of the felsic rock samples are analyzed afterwards a polygon which delineates the distribution of felsic rock samples was constructed from the linear belt of silicate rocks then we generated a system of inequalities based on the equations of the edges of the polygon the application of the inequalities to the aser images shows a good performance of the qmfs for extracting felsic rocks

thermal infrared spectroscopy of experimentally shocked anorthosite and pyroxenite implications for remote sensing of mars 1 the feldspar and pyroxene mineralogies on mars revealed by the thermal emission spectrometer tes on mars global surveyor likely record a variety of shock effects as suggested by petrologic analyses of the martian meteorites and the abundance of impact craters on the planet s surface to study the effects of shock pressures on thermal infrared spectra of these minerals we performed shock recovery experiments on orthopyroxenite and anorthosite samples from the stillwater complex montana over peak pressures from 17 to 63 gpa we acquired emissivity and hemispherical reflectance spectra 350 1400 cm 1 7 29 mm of both coherent chips and fine grained powders of shocked and unshocked samples these spectra are more directly comparable to remotely sensed data of mars e g tes than previously acquired absorption or transmission spectra of shocked minerals the spectra of experimentally shocked feldspar show systematic changes with increasing pressure due to depolymerization of the silica tetrahedra for the spectra of chips this includes the disappearance of small bands in the 500 650 cm 1 region and a strong band at 1115 cm 1 and changes in positions of a strong band near 940 cm 1 and the christiansen feature near 1250 cm 1 spectra of the shocked powders show the gradual disappearance of a transparency feature near 830 cm 1 fewer changes are observed in the pyroxene spectra at pressures as high as 63 gpa spectra of experimentally shocked minerals will help identify more precisely the mineralogy of rocks and soils not only from tes but also from future mars instruments such as minites and themis index terms 3944 mineral physics shock wave experiments 3934 mineral physics optical infrared and raman spectroscopy 5420 planetology solid surface planets impact phenomena includes cratering 5460 planetology solid surface planets physical properties of materials keywords anorthosite pyroxenite shock spectra thermal infrared remote sensing mars

the use of ftir methods for rapid determination of contents of mineral and biogenic components in lake bottom sediments based on studying of east siberian lakes technique for estimation of contents of the major components of lake bottom sediments using single peak analysis procedure has been developed the technique allows estimation of biogenic silica bsi total inorganic carbon tic total organic carbon toc and quartz and feldspars content in bottom sediments the calibration models are based on the following spectral regions bands at 646 cm 1 feldspars 695 cm 1 quartz 874 cm 1 tic the range from 818 to 835 cm 1 bsi the range of c h vibrations 2800 3000 cm 1 toc the technique has been probed for a number of eastern siberian lakes and results are compared with the data of other methods it has been shown that the use of single peak analysis procedure allows very rapid ftir estimation of the major components content in bottom sediments with accuracy which is acceptable for many tasks

quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy 1 application to sedimentary rocks thermal emission spectroscopy is used to determine the mineralogy of sandstone and mudstone rocks as part of an investigation of linear spectral mixing between sedimentary constituent phases with widespread occurrences of sedimentary rocks on the surface of mars critical examination of the accuracy associated with quantitative models of mineral abundances derived from thermal emission spectra of sedimentary materials is necessary although thermal emission spectroscopy has been previously proven to be a viable technique to obtain quantitative mineralogy from igneous and metamorphic materials sedimentary rocks with natural variation of composition compaction and grain size have yet to be examined in this work we present an analysis of the thermal emission spectral 270 1650 cm 1 characteristics of a suite of 13 sandstones and 14 mudstones x ray diffraction and traditional point counting procedures were all evaluated in comparison with thermal emission spectroscopy results from this work are consistent with previous thermal emission spectroscopy studies and indicate that bulk rock mineral abundances can be estimated within 11 2 for detrital grains i e quartz and feldspars and 14 8 for all other mineral phases present in both sandstones and mudstones in comparison to common in situ techniques used for determining bulk rock composition clay sized to fine silt sized grained phase identification is less accurate with differences from the known ranging from 5 to 24 on average nevertheless linear least squares modeling of thermal emission spectra is an advantageous technique for determining abundances of detrital grains and sedimentary matrix and for providing a rapid classification of clastic rocks

optical constants for asian dust in midinfrared region asian dust aerosols are composed of quartz plagioclase k feldspar calcite and phyllosilicates the optical constants for mixtures of these minerals are important not only to understand the effects of asian dust on climate but also to retrieve the properties of asian dust in this work the optical constants for labradorite and orthoclase representative minerals of plagioclase and k feldspar respectively are determined for the spectral range of 500 2000 cm 1 using bidirectional reflectance data from the advanced spaceborne thermal emission and reflection radiometer assuming an internal mixture of component minerals the effective refractive indices for asian dust are calculated using bruggeman s rule the results are proposed as optical constants for asian dust and differ from those for other dust aerosols such as the refractive indices for saharan dust derived from aerosol samples collected at barbados the imaginary refractive index for asian dust is larger indicating more absorptive than the index for saharan dust in the range of 1000 1300 cm 1 using the optical constants derived in this study the brightness temperatures of satellite measurements are simulated for typical loading scenarios of asian dust aerosols the simulated brightness temperatures exhibit a notable decrease with wave number in the region of 800 1000 cm 1 the results also corroborate the spectral features of the atmospheric infrared sounder airs measurements for an asian dust storm airs brightness temperatures near 1223 cm 1 lower than the maximum near 830 cm 1 can also be simulated using the derived optical constants for asian dust

space weathering effects in diviner lunar radiometer multispectral infrared measurements of the lunar christiansen feature characteristics and mitigation multispectral infrared measurements by the diviner lunar radiometer experiment on the lunar renaissance orbiter enable the characterization of the position of the christiansen feature a thermal infrared spectral feature that laboratory work has shown is proportional to the bulk silica content of lunar surface materials diviner measurements show that the position of this feature is also influenced by the changes in optical and physical properties of the lunar surface with exposure to space the process known as space weathering large rayed craters and lunar swirls show corresponding christiansen feature anomalies the space weathering effect is likely due to differences in thermal gradients in the optical surface imposed by the space weathering control of albedo however inspected at high resolution locations with extreme compositions and christiansen feature wavelength positions silica rich and olivine rich areas do not have extreme albedos and fall off the albedo christiansen feature wavelength position trend occupied by most of the moon these areas demonstrate that the christiansen feature wavelength position contains compositional information and is not solely dictated by albedo an optical maturity parameter derived from near ir measurements is used to partly correct diviner data for space weathering influences

infrared spectroscopy in geochemistry exploration geochemistry and remote sensing penelope king michael ramsey and gregg swayze editors mineralogical association of canada short course series volume 33 2004 284 pp isbn 0 921294 33 6 price 40 this 284 page long volume including 20 color plates and an index is a collection of invited papers that originated from a short course on infrared spectroscopy for geoscientists organized by the mineralogical association of canada as outlined in the preface of the volume the main objective of the short course was to update geoscientists on advances in infrared technology being developed in the laboratory through to satellite based systems with particular emphasis on measurement and mapping of mineral composition for more effective ore deposit exploration as well as for environmental monitoring and assessment of natural and anthropogenic processes such a volume would in theory be of interest to readers of economic geology particularly those interested in understanding how a new generation of proximal and remote spectral sensing technologies can be used to measure and target prospective economic mineralization the book essentially aims to

mapping surface mineralogy and scattering behavior using backscattered reflectance from a hyperspectral midinfrared airborne co sub 2 laser system miraco sub 2 las airborne high spectral resolution thermal infrared tir miraco sub 2 las reflectance data were evaluated for mapping surface mineralogy and scattering behavior for a variety of semi arid geological test sites in australia miraco sub 2 las is a rapidly tuned airborne co sub 2 laser system that measures backscattered bidirectional reflectance at 100 wavelengths between 9 1 and 11 2 spl mu m for 2 m footprints in line profile mode an operational methodology is described that permits reduction of the raw airborne signal to ground reflectance this ground reflectance has two major properties namely wavelength dependent mineralogical variations and reflection albedo variations related to surface roughness comparisons between the airborne miraco sub 2 las spectra and laboratory directional hemispherical reflectance dhr spectra show the same spectral shapes though differences in average reflectance albedo occur for some types of rocks the minerals identified using miraco sub 2 las include silicates for example quartz microcline plagiodase almandine spessartine talc tremolite and kaolinite and carbonates dolomite and magnesite as well as vegetation dry and green many of the diagnostic spectral features that allow identification of these materials are narrow 0 2 spl mu m making them difficult to detect with broadband tir systems like the airborne tims and satelliteborne aster based on an empirical relationship between the minimum and maximum reflectance established using laboratory dhr spectra a method is proposed that allows the use of miraco sub 2 las data to identify surfaces that are characterized by lambertian or specular scattering the miraco sub 2 las results show that lambertian type scatterers include soils and many types of isotropic rocks

the nonmarine triassic jurassic boundary in the newark supergroup of eastern north america abstract for the last three decades the position of the triassic jurassic boundary tjb in nonmarine strata has largely been based on its palynostratigraphic placement just below the oldest basalts of the central atlantic magmatic province camp in the newark supergroup of eastern north america this boundary however is demonstrably older than the tjb as it is defined in marine strata thus the palynostratigraphic change used to place this tjb in the newark most resembles a late norian change in the european section and does not correspond to any palynological event at the marine defined tjb conchostracan biostratigraphy suggests that the tjb is in the newark extrusive zone above the oldest camp basalt and vertebrate biostratigraphy is consistent with this placement of the tjb radioisotopic ages indicate that the tjb defined in marine strata is no older than 200 ma but the oldest camp basalts of the newark supergroup consistently yield ages averaging about 201 ma magnetostratigraphic correlation of the newark section to the tjb section at st audrie s bay in england also indicates that the onset of camp volcanism in the newark supergroup is older than the marine tjb correlations based on carbon and osmium isotopes are also consistent with this correlation thus all data indicate that the tjb in the newark supergroup is above the lowest camp basalt in the newark extrusive zone correct placement of the tjb in the newark supergroup allows key nonmarine and marine events to be sequenced across the tjb indicating the following succession of events crurotarsan thecodont extinction the palynofloral turnover in the newark the first camp eruptions the extinctions of rhaetian ammonites and conodonts and the first appearance of jurassic psiloceratid ammonites

automated lithological mapping using airborne hyperspectral thermal infrared data a case study from anchorage island antarctica the thermal infrared portion of the electromagnetic spectrum has considerable potential for mineral and lithological mapping of the most abundant rock forming silicates that do not display diagnostic features at visible and shortwave infrared wavelengths lithological mapping using visible and shortwave infrared hyperspectral data is well developed and established processing chains are available however there is a paucity of such methodologies for hyperspectral thermal infrared data here we present a new fully automated processing chain for deriving lithological maps from hyperspectral thermal infrared data and test its applicability using the first ever airborne hyperspectral thermal data collected in the antarctic a combined airborne hyperspectral survey targeted geological field mapping campaign and detailed mineralogical and geochemical datasets are applied to small test site in west antarctica where the geological relationships are representative of continental margin arcs the challenging environmental conditions and cold temperatures in the antarctic meant that the data have a significantly lower signal to noise ratio than is usually attained from airborne hyperspectral sensors we applied preprocessing techniques to improve the signal to noise ratio and convert the radiance images to ground leaving emissivity following preprocessing we developed and applied a fully automated processing chain to the hyperspectral imagery which consists of the following six steps 1 superpixel segmentation 2 determine the number of endmembers 3 extract endmembers from superpixels 4 apply fully constrained linear unmixing 5 generate a predictive classification map and 6 automatically label the predictive classes to generate a lithological map the results show that the image processing chain was successful despite the low signal to noise ratio of the imagery reconstruction of the hyperspectral image from the endmembers and their fractional abundances yielded a root mean square error of 0 58 the results are encouraging with the thermal imagery allowing clear distinction between granitoid types however the distinction of fine grained intermediate composition dykes is not possible due to the close geochemical similarity with the country rock

comment on ascent of dinosaurs linked to an iridium anomaly at the triassic jurassic boundary olsen et al 1 1 in a detailed study of skeletal remains and fossil footprints in the newark supergroup of eastern north america found that triassic theropods there were all of small to moderate size whereas large theropod bones and footprints such as eubrontes giganteus 35 cm long

a 850 year record climate and vegetation changes in east siberia russia inferred from geochemical and biological proxies of lake sediments east siberia is very sensitive to moisture regimes because it is located in a margin area where moisture from the north atlantic is strongly depleted and the penetration of the east asian monsoon is weak and rare in winter months the siberian anticyclone strongly blocks and reduces the external influences on the region the high latitude of the study area at 52 n is probably sensitive to variation in insolation and solar activity we analysed a 42 cm long sediment record from lake mountain located in east siberia russia for geochemical mineralogical subfossil diatoms chironomids and pollen to provide a reconstruction of the climate history of the area for the last 850 years according to our reconstruction a clear decrease in summer temperatures occurred in east siberia after ca 1400 and we linked this temperature drop with the beginning of the little ice age the coldest summer occurred about ca 1570 1700 and 1830 1900 we assumed that the most significant changes of the lake bio productivity and the catchment area were occurred about ca 1160 1350 1350 1590 1590 1730 1730 1900 and 1940 to the present the most dramatic period with unfavorable climate conditions for lake biota was during 1590 1730

soil erosion processes on row sideslopes within contour ridging systems abstract soil erosion from row sideslopes can result in contour failure and reduce the soil conservation capacity of contour ridges understanding soil erosion processes on row sideslopes and their effects will improve our understanding of soil erosion in contour ridge systems this knowledge will provide guidance for improving the use of contour ridges in this study 32 rainfall simulation experiments were conducted in order to analyze the effects of two different microtopography indices row grade and field slope two ridge geometry indices ridge height and ridge width and rainfall intensity on erosion of sandy brown soil with two replications based on the runoff and sediment yield time series which was monitored over 1 min intervals the soil erosion process was classified into periods of interrill or rill erosion the runoff values for the two periods accounted for approximately 44 2 and 55 8 of the entire runoff value respectively sediment was mainly generated from rill erosion 87 2 however interrill erosion occurred most of the time 72 3 during the interrill erosion period the ridge width and rainfall intensity significantly and positively affected the amount of runoff contributions of 33 1 and 28 7 respectively and sediment yield per min 14 8 and 17 0 respectively ridge height significantly and positively affected the runoff per min but not the sediment yield per min in contrast field slope negatively affected runoff per min which indicated that the runoff during the interrill period was mainly affected by the ridge geometry while the sediment yield per min was mainly affected by the microtopography relief during the rill erosion period the ridge height significantly and negatively affected the runoff per min because the increasing ridge height prolonged the duration of this period and enhanced infiltration and the row grade significantly and positively affected the sediment yield per min which resulted from decreasing soil cohesiveness with increasing row grade the entire runoff and sediment yield per min during the experiment were influenced by the same factors that influenced the interrill and rill erosion periods respectively interactions between the different factors especially between ridge height row grade and rainfall intensity play an important role during the erosion process by increasing runoff and sediment yield per min therefore reducing the field slope and using high ridges may reduce contour failure during rainfall events

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

the effect of slope length on the amount and size distribution of eroded silt loam soils short slope laboratory experiments on interrill erosion abstract the data of rainfall simulation experiments on a sandy loam and a loamy sand were compared to assess the effect of slope length on the soil loss from short slopes between 0 3 and 0 9 m the total soil loss and the aggregate size distribution in the total soil loss were determined after 90 min of rainfall with rainfall intensities between 22 0 and 78 5 m h 1 the experimental results indicated that the slope length effect is different for the two soils although for both soils the total soil loss increased with increasing slope length the soil loss per unit slope length increased with increasing slope length only for the sandy loam soil 1 and decreased with increasing slope length for the loamy sand soil 2 the difference in slope length effect between the two soils was also reflected in the aggregate size distribution in the soil loss the different aggregate sizes displayed different relationships between soil loss and slope length for the loamy sand the slope length effect was less for the large aggregate sizes which contained more sand than the original soil for both soils the slope length effect was most pronounced for the aggregate sizes smaller than 0 05 mm

mid infrared spectroscopy of impactites from the nordlinger ries impact crater abstract this study is part of an effort to build a mid infrared database 7 14 m of spectra for mertis mercury radiometer and thermal infrared spectrometer an instrument onboard of the esa jaxa bepicolombo space probe to be launched to mercury in 2017 mercury was exposed to abundant impacts throughout its history this study of terrestrial impactites can provide estimates of the effects of shock metamorphism on the mid infrared spectral properties of planetary materials in this study we focus on the nordlinger ries crater in southern germany a well preserved and easily accessible impact crater with abundant suevite impactites suevite and melt glass bulk samples from otting and aumuhle as well as red suevite from polsingen were characterized and their reflectance spectra in mid infrared range obtained in addition in situ mid infrared spectra were made from glasses and matrix areas in thin sections the results show similar but distinguishable spectra for both bulk suevite and melt glass samples as well as in situ measurements impact melt glass from aumuhle and otting have spectra dominated by a reststrahlen band at 9 3 9 6 m bulk melt rock from polsingen and bulk suevite and fine grained matrix have their strongest band between 9 4 and 9 6 m there are also features between 8 5 and 9 m and 12 5 12 8 m associated with crystalline phases there is evidence of weathering products in the fine grained matrix such as smectites mercury endured many impacts with impactors of all sizes over its history so spectral characteristics observed for impactites formed only in a single impact like in the ries impact event can be expected to be very common on planetary bodies exposed to many more impacts in their past we conclude that in mid infrared remote sensing data the surface of mercury can be expected to be dominated by features of amorphous materials

ore detection and grade estimation in the sudbury mines using thermal infrared reflectance spectroscopy this pilot study investigated the usefulness of thermal infrared reflectance tir spectroscopy to estimate ore grade in an underground environment and to separate ore bearing samples from their host rocks work was carried out under laboratory conditions to test the initial concept all samples had naturally broken faces to mimic the situation in a freshly blasted underground opening a total of 26 samples including massive and disseminated ores were collected from eight mines around the sudbury basin in ontario rock surfaces were measured wet and dry to address environmental conditions encountered underground to separate barren rocks from ores and for ore grade estimation an important finding of this research is that in the region of 1319cm 1 most known silicate minerals converge to a common reflectance minima 1 5 but massive and disseminated sulfides have distinctly higher reflectance individual sulfide minerals chalcopyrite pyrrhotite pentlandite however do not reveal diagnostic fea

low temperature specific heat capacity measurements and application to mars thermal modeling abstract data returned from martian missions have revealed a wide diversity of surface mineralogies including in geological structures interpreted to be sedimentary or altered by liquid water these terrains are of great interest because of their potential to document the environment at a time when life may have appeared intriguingly martian sedimentary rocks show distinctly low thermal inertia values i e 300 700 jm 2k 1s 1 2 indicative of a combination of low thermal conductivity specific heat capacity and density these low values are difficult to reconcile with their competent bedrock morphologies whereas hundreds of bedrock occurrences interpreted as volcanic in origin have been mapped globally and display thermal inertia values 1200 jm 2k 1s 1 2 bedrock thermal inertia values are generally assumed to be driven by their bulk thermal conductivity which in turn is controlled by their micro and macro physical properties i e degree and style of cementation in the case of detritic rocks horizontal fractures and layering etc and not by their density well known from terrestrial analog measurements and with modest variability or specific heat capacity generally uncharacterized for non basaltic materials below room temperature in this paper we demonstrate that specific heat capacity cannot be a potential cause for the differential thermophysical behavior between magmatic and sedimentary rocks through a series of experimental cp t measurements at 100 350 k using differential scanning calorimetry the results on 20 martian relevant minerals investigated in this work indicate that these materials exhibit very similar specific heats ranging from 0 3 0 7 jg 1k 1 at 100 k to 0 6 1 7 jg 1k 1 at 350 k when used in a martian thermal model this range of cp values translate to very small surface temperature differences indicating that uncertainty in composition and its effect on the specific heat is not a noticeable source of thermal inertia variability for indurated units on mars we therefore conclude that the low thermal inertia value of sedimentary rocks compared to magmatic volcanic rocks is likely due to their low apparent bulk conductivity which bears information on their internal physical structure future work combining the analysis of thermal observations acquired at various local times and seasons will help further characterize this heterogeneity

thermal infrared spectroscopy and partial least squares regression to determine mineral modes of granitoid rocks 1 in this paper we present an approach to extracting mineralogic information from thermal infrared tir spectra that is not based on an input library of pure mineral spectra nor tries to extract spectral end members from the data instead existing modal mineralogy for a number of samples are used to build a partial least squares regression plsr model that links the mineralogy of the samples to their respective tir spectral signatures the resulting plsr models can be applied to a larger group of samples for which the mineralogic composition can be estimated from the tir spectra alone thermal infrared reflectance spectra were recorded from 1330 625 cm 1 7 5 to 16 0 m the method is tested on igneous rocks from a porphyry copper deposit in yerington nevada as a reference modal mineralogic composition was determined with traditional polarization microscopy on thin sections partial least squares regression models were developed to link the thermal infrared spectra to the thin section determined mineral modes of alkali feldspar plagioclase and quartz as well as the average plagioclase composition information results indicate that rock samples can be classified successfully in a quartz alkali feldspar plagioclase diagram based on thermal infrared spectroscopy and partial least squares regression modeling estimated errors for the mineralogic composition model results were found to be smaller or equal to traditional methods with errors of 5 1 absolute for alkali feldspar 8 5 absolute for plagioclase and 6 9 absolute for quartz the regression model for plagioclase composition predicted with estimated errors of 7 8 mol anorthite

thermal infrared spectroscopy on feldspars successes limitations and their implications for remote sensing abstract minerals of the feldspar group are the most common on earth feldspars are economically important in two ways either as industrial minerals or as a vector to ore for mineral deposits in order to use feldspars for classifying rock compositions or metasomatic conditions during rock alteration events there is a need for analytical methods to identify and classify feldspars traditionally feldspar composition and structure have been investigated using methods such as optical microscopy electron microprobe analysis empa cathodoluminescence and x ray diffraction xrd analysis in this paper infrared techniques 0 7 25 m are reviewed in detail and investigated in how far some of the traditional analytical methods can be replaced by infrared spectroscopy successes as well as limitations of infrared approaches are highlighted and existing work is scrutinized in terms of its applicability to remote sensing techniques even though numerous studies on mid infrared mir spectroscopy of feldspars exist their results often cannot be directly related to remote sensing applications examples are the effects of feldspar twinning exsolution textures and structural state on infrared spectra the applicability of the results to emission remote sensing requires further research it has been shown that linear unmixing of laboratory infrared spectra of rocks works fairly well detection limits for feldspar are around 5 and plagioclase composition can be determined within error margins of 4 anorthite component infrared spectroscopy can however not detect compositional zonation or different generations of feldspars infrared spectra represent the current average plagioclase and average alkali feldspar composition in the sample with several new airborne instruments under development it is opportune to focus upcoming research efforts on developing standardized processing techniques and spectral feldspar indices for thermal infrared imagery commercially interesting products include numbers of feldspars species plagioclase and alkali feldspar composition their structural state and relative or semi quantitative abundance in the rocks

basaltic rocks analyzed by the spirit rover in gusev crater the spirit landing site in gusev crater on mars contains dark fine grained vesicular rocks interpreted as lavas pancam and mini thermal emission spectrometer mini tes spectra suggest that all of these rocks are similar but have variable coatings and dust mantles magnified images of brushed and abraded rock surfaces show alteration rinds and veins rock interiors contain 25 megacrysts chemical analyses of rocks by the alpha particle x ray spectrometer are consistent with picritic basalts containing normative olivine pyroxenes plagioclase and accessory feti oxides mossbauer pancam and mini tes spectra confirm the presence of olivine magnetite and probably pyroxene these basalts extend the known range of rock compositions composing the martian crust

thermal infrared 2 5 13 5 μm spectroscopic remote sensing of igneous rock types on particulate planetary surfaces fundamental molecular vibration bands are significantly diminished by scattering thus such bands in spectra of fine particulate regoliths i e dominated by 5 m particles or regoliths displaying a similar scale of porosity are difficult to use for mineralogical or rock type identification consequently other spectral features have been sought that may be more useful in spectroscopic remote sensing of composition we find that mineralogical information is retained in overtones and combination tones of the fundamental molecular vibrations in the 3 0 to 7 0 m region but that relatively few minerals have a sufficiently distinctive band structure to be unambiguously identified with currently available techniques more significantly identification of general rock type as defined by the scfm chemical index scfm sio2 sio2 cao feo mgo is possible using spectral features associated with the principal christiansen frequency and with a region of relative transparency between the si o stretching and bending bands however environmental factors may affect the appearance and wavelengths of these features finally prominent absorption bands may result from the presence of relatively small amounts of water hydroxyl or carbonate because absorption bands exhibited by these materials in the 2 7 to 4 0 m region where silicate spectra are otherwise featureless increase strongly in spectral contrast with decreasing particle size such materials are thus detectable in very small amounts in a particulate regolith composed predominantly of silicate minerals

distribution and variation of plagioclase compositions on mars 1 this study presents the first global compositional maps of plagioclase the most abundant mineral in the martian crust linear deconvolutions of spectra from the thermal emission spectrometer tes allowed calculation of average plagioclase compositions for dust free areas on mars 60 of the equator approximately 40 of the surface for this range of latitudes as a whole surface type 1 and 2 terrains are virtually identical with respect to their average plagioclase compositions an60 the majority of tes observations were modeled as labradorite and bytownite between an50 and an90 while fewer observations were modeled with other plagioclase compositions that did not correlate with specific geologic terrains the lack of diversity in average plagioclase compositions across multiple geologic units may represent an upper martian crust with minimal variation in plagioclase compositions alternatively aeolian fluvial and or impact activity may have redistributed heterogeneous crustal material forming a relatively homogeneous global surface layer

global assessment of pure crystalline plagioclase across the moon and implications for the evolution of the primary crust recent advancements in visible to near infrared orbital measurements of the lunar surface have allowed the character and extent of the primary anorthositic crust to be studied at unprecedented spatial and spectral resolutions here we assess the lunar primary anorthositic crust in global context using a spectral parameter tool for moon mineralogy mapper data to identify and map fe bearing crystalline plagioclase based on its diagnostic 1 25 m absorption band this allows plagioclase dominated rocks specifically anorthosites to be unambiguously identified as well as distinguished from lithologies with minor to trace amounts of mafic minerals low spatial resolution global mosaics and high spatial resolution individual data strips covering more than 650 targeted craters were analyzed to identify and map the mineralogy of spectrally pure regions as small as 400 m in size spectrally pure plagioclase is identified in approximately 450 targets located across the lunar surface diviner thermal infrared tir data are analyzed for 37 of these nearly monomineralic regions in order to understand the compositional variability of plagioclase an in these areas the average an for each spectrally pure region is estimated using new laboratory measurements of a well characterized anorthite an96 sample diviner tir results suggest that the plagioclase composition across the lunar highlands is relatively uniform high in calcium content and consistent with plagioclase compositions found in the ferroan anorthosites an94 98 our results confirm that spectrally pure anorthosite is widely distributed across the lunar surface and most exposures of the ancient anorthositic crust are concentrated in regions of thicker crust surrounding impact basins on the lunar nearside and farside in addition the scale of the impact basins and the global nature and distribution of pure plagioclase requires a coherent zone of anorthosite of similar composition in the lunar crust supporting its formation from a single differentiation event like a magma ocean our identifications of pure anorthosite combined with the grail crustal thickness model suggest that pure anorthosite is currently observed at a range of crustal thickness values between 9 and 63 km and that the primary anorthositic crust must have been at least 30 km thick

laboratory emissivity measurements of the plagioclase solid solution series under varying environmental conditions 1 new laboratory thermal infrared emissivity measurements of the plagioclase solid solution series over the 1700 400 cm 1 6 25 m spectral range are presented thermal infrared tir spectral changes for fine particulate samples 0 25 m are characterized for the first time under different laboratory environmental conditions ambient terrestrial like half vacuum mars like vacuum and vacuum with cooled chamber lunar like under all environmental conditions the christiansen feature cf is observed to vary in a systematic way with na rich end member albite having a cf position at the highest wave number shortest wavelength and the ca rich end member anorthite having a cf position with the lowest wave number longest wavelength as pressure decreases to 10 3 mbar four observations are made 1 the cf position shifts to higher wave numbers 2 the spectral contrast of the cf increases relative to the rb 3 the spectral contrast of the rb in the 1200 900 spectral range decreases while the spectral contrast of the rb in the 800 400 spectral range either increases or remains the same and 4 the tf disappears a relationship between the wavelength position of the cf measured under simulated lunar conditions and plagioclase composition an is developed although its exact form may evolve with additional data this linear relationship should be applied to current and future tir data sets of the moon our new spectral measurements demonstrate how sensitive thermal infrared emissivity spectra of plagioclase feldspars are to the environmental conditions under which they are measured and provide important constraints for interpreting current and future thermal infrared data sets

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

analysis of terrestrial and martian volcanic compositions using thermal emission spectroscopy 2 application to martian surface spectra from the mars global surveyor thermal emission spectrometer atmospherically corrected thermal infrared spectra of large regions of the martian surface from the mars global surveyor thermal emission spectrometer mgs tes previously have been interpreted to represent two general spectral classes one class represents a basalt to basaltic andesite composition and the other class represents a basaltic andesite to andesite composition we have performed new linear deconvolutions of the two martian surface type spectra with an end member set tailored to represent volcanic rock types our preparatory study of laboratory spectra of terrestrial volcanic rocks acquired at 2 cm 21 sampling convolved to tes spectral sampling 10 cm 21 shows little degradation in deconvolution results when compared to results acquired using the higher spectral resolution data indicating that the deconvolution technique is valid for analyzing data at tes resolution our spectral fits to the martian data agree well with previous models and do not exhibit any notable deviations from the martian spectra that would indicate the absence of any significant end members in our model modal mineralogies obtained with these new spectral fits also compare favorably within the previously stated uncertainties to prior results the newly derived modal mineralogies are used with new and traditional classification schemes for volcanic igneous rocks introduced in a companion paper wyatt et al this issue to classify the martian compositions our results substantiate the previously proposed hypothesis that these two spectral classes on the martian surface represent volcanic compositions with distinguishable differences in silica content ranging from basalt to andesite

thermal infrared remote sensing and kirchhoff s law 1 laboratory measurements by the end of this century the earth observing system eos will provide worldwide thermal infrared multispectral images of the earth presenting geologists with a new kind of remote sensing data for interpretation thus it has become essential to understand the spectral emittance behavior of terrestrial surface materials perhaps the most fundamental question to be answereed is the extent to which such materials follow kirchhoff s law epsilon 1 r under laboratory and field conditions especially when a sample displays a thermal gradient we present the first rigorous quantitative comparison of directional and hemispherical reflectance and directional emittance of rock and soil samples in the laboratory with thermal gradients induced by heating them from below and allowing them to radiate to a colder background the results show that only an extemeley low density sample composed of fine particles sifted into a fairy castle structure displays a thermal gradient steep enough within the infrared skin depth to cause significant 6 departure from kirchhoff s law there is no detectable effect on the more normal terrestrial samples such as soils and rocks measured in the laboratory even when semitransparent coatings are involved thus both emittance and reflectance measurements can be used to calculate sample emissivity for most terrestrial surface materieals however the effect on kirchhoffian behavior of different field environments which may induce a steeper thermal gradient in particulate samples has yet to be determined and some low density surface materials like newly fallen snow frost and efflorescent salts on playas have yet to be measured in emittance

plagioclase compositions derived from thermal emission spectra of compositionally complex mixtures implications for martian feldspar mineralogy 1 the compositions of plagioclase the most abundant mineral in the martian crust reflect changing conditions during magmatic evolution plagioclase contains spectral features at thermal infrared wavelengths that permit its detection by thermal emission spectrometers thermal emission spectrometer tes thermal emission imaging system themis and miniature tes mini tes on mars spacecraft previous studies have determined the accuracy with which average plagioclase compositions can be modeled in simple two component sand mixtures and terrestrial volcanic rocks studies of terrestrial rock analogs suffer from difficulties in accurately determining the average plagioclase composition for comparison with the spectrally modeled composition sand mixtures however provide a means of controlling plagioclase compositions for direct comparison to those modeled by linear deconvolution this has allowed us to address how compositional complexity may affect our ability to derive average plagioclase compositions from thermal emission data in this study we examine the accuracy with which average plagioclase compositions can be modeled from emission spectra of complex mixtures of three four and five compositions of coarse 500 850 m plagioclase sand additionally we examine multiphase mixtures of plagioclase with pyroxene olivine magnetite and ilmenite that are analogous to selected martian surface materials increasing the number of plagioclase compositions or introducing additional mineral phases does not affect the accuracy previously reported for modeling average plagioclase compositions plagioclase can be modeled to within 6 an of measured compositions at laboratory tes themis and mini tes resolution within 1 standard deviation

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

constraints on olivine rich rock types on the moon as observed by diviner and m3 implications for the formation of the lunar crust we place upper limits on lunar olivine abundance using midinfrared 5 25 m data from the lunar reconnaissance orbiter diviner lunar radiometer experiment diviner along with effective emissivity spectra of mineral mixtures in a simulated lunar environment olivine bearing pyroxene poor lithologies have been identified on the lunar surface with visible near infrared vnir observations since the kaguya spectral profiler sp vnir survey of olivine rich regions is the most complete to date we focus this work on exposures identified by that study we first confirmed the locations with vnir data from the moon mineralogy mapper m3 instrument we then developed a diviner olivine index from our laboratory data which along with m3and lunar reconnaissance orbiter camera wide angle camera data was used to select the geographic area over which diviner emissivity data were extracted we calculate upper limits on olivine abundance for these areas using laboratory emissivity spectra of anorthite forsterite mixtures acquired under lunar like conditions we find that these exposures have widely varying olivine content in addition after applying an albedo based space weathering correction to the diviner data we find that none of the areas are unambiguously consistent with concentrations of forsterite exceeding 90 wt in contrast to the higher abundance estimates derived from vnir data 2016 american geophysical union

sebass hyperspectral thermal infrared data surface emissivity measurement and mineral mapping this study focuses on mapping surface minerals using a new hyperspectral thermal infrared tir sensor the spatially enhanced broadband array spectrograph system sebass sebass measures radiance in 128 contiguous spectral channels in the 7 5 to 13 5 m region with a ground spatial resolution of 2 m in september 1999 three sebass flight lines were acquired over virginia city and steamboat springs nevada at sensor data were corrected for atmospheric effects using an empirical method that derives the atmospheric characteristics from the scene itself rather than relying on a predicted model the apparent surface radiance data were reduced to surface emissivity using an emissivity normalization technique to remove the effects of temperature mineral maps were created with a pixel classification routine based on matching instrument and laboratory measured emissivity spectra similar to methods used for other hyperspectral data sets e g aviris linear mixtures of library spectra match sebass spectra reasonably well and silicate and sulfate minerals mapped remotely agree with the dominant minerals identified with laboratory x ray powder diffraction and spectroscopic analyses of field samples though improvements in instrument calibration atmospheric correction and information extraction would improve the ability to map more pixels these hyperspectral tir data nevertheless show significant advancement over multispectral thermal imaging by mapping surface materials and lithologic units with subtle spectral differences in mineralogy

use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the yimeng mountain region china information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human influenced landscapes that have been subjected to recent environmental changes and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers the yimeng mountain region characterized by alternating granite and limestone is one of the most susceptible regions to soil erosion in northern china and has been subjected to intensive anthropogenic activity in recent years soil loss from areas underlain by granite is particularly obvious and is the main sediment source for the yihe river in this study we used reservoir deposits to estimate the changes in sediment yields over the past 50 years from a small catchment underlain by granite namely the jiangzhuang catchment in the yimeng mountain region three cores were collected from the jiangzhuang reservoir in the catchment the activities of 137cs and 210pbex at different depths clay grain size 5 m contents and sedimentary organic carbon soc contents in the cores were analysed with reference to human activity and environmental change in the catchment the chronologies of the cores were established by 137cs and 210pbex dating the area specific sediment yield ssy for different time periods since dam construction was estimated from each core by referring to the original capacity curve of the reservoir the results indicate that the depth profiles of 137cs 210pbex clay and soc contents in cores from the jiangzhuang reservoir reflect the general history of human disturbances on the catchment over the past 50 years the estimated ssy value from each core for each period ranged from 7 2 2 7 to 23 7 8 3 t ha 1 y 1 with a mean of 12 5 4 6 t ha 1 y 1 ssy decreased during 1954 1972 and then showed a general tendency to increase the temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment

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

identification of sand sources and transport pathways at the kelso dunes california using thermal infrared remote sensing the kelso dune field is located in the eastern mojave desert california at the terminus of a sand transport pathway which has its primary source at the mojave river wash 50 km to the west initial examination of 1984 airborne thermal infrared multispectral scanner tims data showed significant spectral variations that indicate potential mineralogic heterogeneities within the active dunes this result prompted the collection of a suite of 48 sand samples in 1990 and the acquiring of new tims data in 1995 this new data set was used to test a newly developed linear spectral retrieval algorithm in conjunction with a spectral library of end member minerals results of this analysis produced images of end member minerals that showed marked variations within the dunes in addition standard petrographic techniques revealed that the dunes contain mineralogic variations and were much less quartz rich 42 than previously reported 70 90 point count results agreed with the spectral data to within an average of 5 3 for tims derived and 3 1 for laboratory derived mineralogic abundances high concentrations of several of the end member minerals on the surrounding alluvial fans indicate a potential nearby source for these minerals most evident is the presence of potassium feldspar from the fan that emanates from the providence mountains east of the dunes this previously unidentified potential sand input is not visible with other remote sensing techniques and was confirmed with additional field sampling much of the quartz and some plagioclase feldspar however appear to have been transported from the mojave river wash source as previously reported this study also validates the potential of using thermal remote sensing from future satellite based instruments to globally monitor desert fringe areas susceptible to the changing conditions of sand encroachment

thermal infrared spectroscopy and modeling of experimentally shocked plagioclase feldspars thermal infrared emission and reflectance spectra 250 1400 cm 1 7 40 m of experimentally shocked albite and anorthite rich rocks 17 56 gpa demonstrate that plagioclase feldspars exhibit characteristic degradations in spectral features with increasing pressure new measurements of albite ab98 presented here display major spectral absorptions between 1000 1250 cm 1 8 10 m due to si o antisymmetric stretch motions of the silica tetrahedra and weaker absorptions between 350 700 cm 1 14 29 m due to si o si octahedral bending vibrations many of these features persist to higher pressures compared to similar features in measurements of shocked anorthite consistent with previous thermal infrared absorption studies of shocked feldspars a transparency feature at 855 cm 1 11 7 m observed in powdered albite spectra also degrades with increasing pressure similar to the 830 cm 1 12 0 m transparency feature in spectra of powders of shocked anorthite linear deconvolution models demonstrate that combinations of common mineral and glass spectra can replicate the spectra of shocked anorthite relatively well until shock pressures of 20 25 gpa above which model errors increase substantially coincident with the onset of diaplectic glass formation albite deconvolutions exhibit higher errors overall but do not change significantly with pressure likely because certain clay minerals selected by the model exhibit absorption features similar to those in highly shocked albite the implication for deconvolution of thermal infrared spectra of planetary surfaces or laboratory spectra of samples is that the use of highly shocked anorthite spectra in end member libraries could be helpful in identifying highly shocked calcic plagioclase feldspars

first use of an airborne thermal infrared hyperspectral scanner for compositional mapping in may 1999 the airborne thermal infrared hyperspectral imaging system spatially enhanced broadband array spectrograph system sebass was flown over mormon mesa nv to provide the first test of such a system for geological mapping several types of carbonate deposits were identified using the 11 25 m band however massive calcrete outcrops exhibited weak spectral contrast which was confirmed by field and laboratory measurements because the weathered calcrete surface appeared relatively smooth in hand specimen this weak spectral contrast was unexpected here we show that microscopic roughness not readily apparent to the eye has introduced both a cavity effect and volume scattering to reduce spectral contrast the macroroughness of crevices and cobbles may also have a significant cavity effect the diminished spectral contrast is important because it places higher signal to noise ratio snr requirements for spectroscopic detection and identification this effect should be factored into instrumentation planning and interpretations especially interpretations without benefit of ground truth sebass had the required high snr and spectral resolution to allow us to demonstrate for the first time the ability of an airborne hyperspectral thermal infrared scanner to detect and identify spectrally subtle materials

the aster spectral library version 2 0 abstract the advanced spaceborne thermal emission reflection radiometer aster on nasa s terra platform has been widely used in geological and other science studies in support of aster studies a library of natural and man made materials was compiled as the aster spectral library v1 2 and made available from http speclib jpl nasa gov the library is a collection of contributions in a standard format with ancillary data from the jet propulsion laboratory jpl johns hopkins university jhu and the united states geological survey usgs a new version of the library v2 0 is now available online or via cd which includes major additions to the mineral and rock spectra the aster library provides a comprehensive collection of over 2300 spectra of a wide variety of materials covering the wavelength range 0 4 15 4 m

thermal infrared emissivity measurements under a simulated lunar environment application to the diviner lunar radiometer experiment 1 we present new laboratory thermal infrared emissivity spectra of the major silicate minerals identified on the moon measured under lunar environmental conditions and evaluate their application to lunar remote sensing data sets thermal infrared spectral changes between ambient and lunar environmental conditions are characterized for the first time over the 400 1700 cm 1 6 25 m spectral range for a fine particulate mineral suite including plagioclase albite and anorthite pyroxene enstatite and augite and olivine forsterite the lunar environment introduces observable effects in thermal infrared emissivity spectra of fine particulate minerals which include 1 a shift in the christiansen feature cf position to higher wave numbers shorter wavelengths 2 an increase in the overall spectral contrast and 3 decreases in the spectral contrast of the reststrahlen bands and transparency features our new measurements demonstrate the high sensitivity of thermal infrared emissivity spectra to environmental conditions under which they are measured and provide important constraints for interpreting new thermal infrared data sets of the moon including the diviner lunar radiometer experiment onboard nasa s lunar reconnaissance orbiter full resolution laboratory mineral spectra convolved to diviner s three spectral channels show that spectral shape cf position and band ratios can be used to distinguish between individual mineral groups and lunar lithologies the integration of the thermal infrared cf position with near infrared spectral parameters allows for robust mineralogical identifications and provides a framework for future integrations of data sets across two different wavelength regimes

investigating the shock histories of lunar meteorites miller range 090034 090070 and 090075 using petrography geochemistry and micro ftir spectroscopy fourier transform infrared ftir spectroscopy and cathodoluminescence cl imaging techniques combined with electron microprobe analyses have been used to determine the physical state of feldspathic phases that have been subject to varying levels of shock in the grouped lunar meteorites miller range 090034 090070 and 090075 six feldspathic phases have been identified based on spectral textural and chemical properties a specific infrared wavelength band ratio 1064 932 cm 1 equivalent to 9 40 10 73 m chosen because it can distinguish between some of the feldspathic phases can be used to estimate the pressure regimes experienced by these phases in addition ftir spatial mapping capabilities allow for visual comparison of variably shocked phases within the samples by comparing spectral and compositional data the origin and shock history of this lunar meteorite group has been determined with each of the shocked feldspathic phases being related to events in its geological evolution as such we highlight that ftir spectroscopy can be easily employed to identify shocked feldspathic phases in lunar samples estimate peak shock pressures and when compared with chemical data can be used to investigate their shock histories

the m3 project 2 global distributions of mafic mineral abundances on mars abstract a radiative transfer model was used to reproduce several millions of omega observatoire pour la mineralogie l eau les glaces et l activite spectra representative of igneous terrains of mars this task provided the modal composition and grain sizes at a planetary scale the lithology can be summarized in five mineral maps at km scale we found that the low albedo equatorial regions of the martian surface from 60 s to 30 n are globally dominated by plagioclase with average abundance 50 vol and pyroxenes with total averaged abundance close to 40 vol an evolution of the lcp lcp hcp ratio is observed with time at the global scale suggesting an evolution of the degree of partial melting throughout the martian eras olivine and martian dust are minor components of the modelled terrains the olivine distribution is quite different from the other minerals because it is found on localized areas with abundance reaching 20 vol a statistical approach to classify the pixels of the abundances maps using k means clustering highlighted seven distinct mineral assemblages on the surface this classification illustrates that diverse mineralogical units are found in the noachian and hesperian terrains which suggests the presence of various and complex magmatic processes at a global scale during the two oldest eras the chemical composition was derived from the modal composition maps the omega derived chemical composition is quite consistent with several distinctive geochemical characteristics previously considered as fingerprints of the martian surface a major discrepancy is in regards to the fe content that is significantly smaller than soil and rock analyses from grs and in situ measurements the discrepancy could be partly explained by the assumptions used for the spectral modelling or could also indicate surface alteration rinds

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

mid infrared spectral variability for compositionally similar asteroids implications for asteroid particle size distributions abstract we report an unexpected variability among mid infrared spectra irtf and spitzer data of eight s type asteroids for which all other remote sensing interpretations e g vnir spectroscopy albedo yield similar compositions compositional fitting making use of their mid ir spectra only yields surprising alternative conclusions 1 these objects are not compositionally similar as the inferred abundances of their main surface minerals olivine and pyroxene differ from one another by 35 and 2 carbonaceous chondrite and ordinary chondrite meteorites provide an equally good match to each asteroid spectrum following the laboratory work of ramsey and christensen ramsey m s christensen p r 1998 j geophys res 103 577 596 we interpret this variability to be physically caused by differences in surface particle size and or the effect of space weathering processes our results suggest that the observed asteroids must be covered with very fine

analysis of terrestrial and martian volcanic compositions using thermal emission spectroscopy 1 determination of mineralogy chemistry and classification strategies we have examined and applied existing classification schemes for volcanic rocks and developed new schemes using thermal emission spectra of terrestrial volcanic rocks laboratory thermal infrared spectra 5 25 m at 2 cm 1 spectral sampling deconvolved modal mineralogies and derived mineral and bulk rock chemistries were used to distinguish basalt basaltic andesite andesite and dacite modal mineralogies derived from linear deconvolution of terrestrial volcanic rocks were compared to modes measured by an electron microprobe phase mapping technique to determine the accuracy of linear deconvolution in modeling specific mineral abundances one standard deviations of the absolute differences between modeled and measured mineral abundances range from 2 4 to 12 2 vol with an average standard deviation of 4 8 vol being in agreement with average uncertainties calculated in previous studies weighted average compositions of feldspars in the deconvolution generally overlap the measured ranges of plagioclase compositions and the presence of low calcium and high calcium pyroxenes was correctly identified bulk chemistries of volcanic rocks were derived with a relatively high degree of accuracy 1 standard deviations ranging from 0 4 to 2 6 vol by combining the compositions of spectrally modeled phases in proportion to their relative abundances in a particular sample these data were collectively used to examine existing and develop new volcanic rock classification schemes however no single classification scheme was effective in accurately classifying all samples multiple steps of classification were required to distinguish volcanic rocks reflecting the mineralogic diversity and continuum of compositions that exists in volcanic rock types in a companion paper hamilton et al this issue these schemes are applied to the classification of martian surface compositions

sediment transport in rill flow under deposition and detachment conditions the understanding of soil erosion processes and the development of accurate erosion prediction models require understanding of detachment deposition and sediment transport in rills the objectives of this study were to determine whether sediment transport capacity is a unique value for given soil flow rate and slope and to determine if equilibrium sediment concentration in the rill obtained by detachment was different from that observed under depositional conditions experiments on a carmi loam fine mixed mesic typic hapludalf simulated rill erosion under net detachment and net deposition conditions two discharge rates of 6 and 9 l min 1 and two sediment input regimes of 0 and excess of transport capacity were tested on soil beds with lengths of 2 4 6 7 and 8 m at 7 slope sediment load reached steady state conditions within the 8 m distance on the rill at 9 l min 1 discharge 8 m length and excess sediment added to the flow sediment delivery was 71 g l 1 versus 31 g l 1 for the corresponding case with no sediment added overall for the conditions tested rill flow transported two times more sediment than it could detach the flow did not reach its maximum potential transported load through detachment of soil due in part to changes in the sediment size distribution under deposition and possibly to the protective action of bedload particles moving along the rill bottom and or changes in flow turbulence associated with sediment laden flow d 2003 elsevier science b v all rights reserved

selection of hyspiri optimal band positions for the earth compositional mapping using hytes data abstract the national aeronautics and space administration nasa has proposed the launch of a new space borne sensor called hyspiri hyperspectral and infrared imager which will cover the spectral range from 0 4 12 m two instruments will be mounted on hyspiri platform 1 a hyperspectral instrument which can sense earth surface between 0 4 and 2 5 m at 10 nm intervals and 2 a multispectral infrared sensor will acquire images between 3 and 12 m in eight spectral bands one in mid infrared mir and seven in thermal infrared tir the tir spectral wavebands will be positioned based on their importance in various applications this study aimed to identify hyspiri optimal tir wavebands position for earth compositional mapping a genetic algorithm coupled with the spectral angle mapper ga sam was used as a spectral bands selector high dimensional hytes hyperspectral thermal emission spectrometer emissivity spectra comprised of 202 spectral bands of cuprite and death valley regions were used to select meaningful subsets of bands for earth compositional mapping the ga sam was trained for fifteen mineral classes and the algorithms were run iteratively 50 times high calibration 95 and validation 90 accuracies were achieved with a limited number seven of spectral bands selected by ga sam the knowledge of important band positions will help the scientists of the hyspiri group to place spectral bands in regions where accuracies of earth compositional mapping can be enhanced

infrared reflectance spectra 2 2 15 μm of plagioclase feldspars laboratory results show that 1 the christiansen frequency cf feature in mid infrared reflectance spectra of powders can be used to accurately distinguish plagioclase composition and 2 the wavelength position of the cf is not affected by vitrification of the plagioclase although the cf position does not distinguish glass from crystalline forms of plagioclase other features combination tone overtone restrahlen bands in the mid ir spectra of plagioclase can be used for that purpose these results have important implications for application of thermal emission spectroscopy to mapping the surface composition of regolith covered planetary bodies like the moon mars and asteroids

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

composition and thermal inertia of the mawrth vallis region of mars from tes and themis data abstract clay mineral bearing deposits previously discovered on mars with near infrared 0 3 5 m remote sensing data are of major significance for understanding the aqueous history geological evolution and past habitability of mars in this study we analyzed the thermal infrared 6 35 m surface properties of the most extensive phyllosilicate deposit on mars the mawrth vallis area clay mineral bearing units which in visible images appear to be relatively light toned layered bedrock have thermal inertia values ranging from 150 to 460 j m 2 k 1 s 1 2 this suggests the deposits are composed of a mixture of rock with sand and dust at 100 meter scales dark toned materials that mantle the clay bearing surfaces have thermal inertia values ranging from 150 to 800 indicating variable degrees of rockiness or induration of this younger sedimentary or pyroclastic unit thermal emission spectrometer tes spectra of the light toned rocks were analyzed with a number of techniques but none of the results shows a large phyllosilicate component as has been detected in the same surfaces with near infrared data instead tes spectra of light toned surfaces are best modeled by a combination of plagioclase feldspar high silica materials similar to impure opaline silica or felsic glass and zeolites we propose three hypotheses for why the clay minerals are not apparent in thermal infrared data including effects due to surface roughness sub pixel mixing of multiple surface temperatures and low absolute mineral abundances combined with differences in spatial sampling between instruments zeolites modeled in tes spectra could be a previously unrecognized component of the alteration assemblage in the phyllosilicate bearing rocks of the mawrth vallis area tes spectral index mapping suggests that fe mg clays detected with near infrared data correspond to trioctahedral fe2 clay minerals rather than nontronite like clays the average mineralogy and geologic context of these complex interbedded deposits suggests they are either aqueous sedimentary rocks altered pyroclastic deposits or a combination of both

spectral characterization and aster based lithological mapping of an ophiolite complex a case study from neyriz ophiolite sw iran abstract the neyriz ophiolite occurs along the zagros suture zone in sw iran and is part of a 3000 km obduction belt thrusting over the edge of the arabian continent during the late cretaceous this complex typically consists of altered dunites and peridotites layered and massive gabbros sheeted dykes and pillow lavas and a thick sequence of radiolarites reflectance and emittance spectra of neyriz ophiolite rock samples were measured in the laboratory and their spectra were used as endmembers in a spectral feature fitting sff algorithm laboratory spectral reflectance measurements of field samples showed that in the visible through shortwave infrared vnir swir wavelength region the ultramafic and gabbroic rocks are characterized by ferrous iron and fe mg oh spectral features and the pillow lavas and radiolarites are characterized by spectral features of ferric iron and al oh the laboratory spectral emittance spectra also revealed a wide wavelength range of si o spectral features for the ophiolite rock units after continuum removal of the spectra the sff classification method was applied to the vnir swir 9 band stack and to the 11 band data set of swir and tir data sets of the advanced spaceborne thermal emission and reflection radiometer aster sensor using field spectra as training sets for evaluating the potential of these data sets in discriminating ophiolite rock units output results were compared with the geological map of the area and field observations and were assessed by the use of confusion matrices the assessment showed in terms of kappa coefficient that the sff classification method with continuum removal applied to the swir data achieved excellent results which were distinctively better than those obtained using vnir swir data and tir data alone