spirit mars rover mission to the columbia hills gusev crater mission overview and selected results from the cumberland ridge to home plate this paper summarizes the spirit rover operations in the columbia hills of gusev crater from sols 513 to 1476 and provides an overview of selected findings that focus on synergistic use of the athena payload and comparisons to orbital data results include discovery of outcrops voltaire on husband hill that are interpreted to be altered impact melt deposits that incorporated local materials during emplacement evidence for extensive volcanic activity and aqueous alteration in the inner basin is also detailed including discovery and characterization of accretionary lapilli and formation of sulfate silica and hematite rich deposits use of spirit s data to understand the range of spectral signatures observed over the columbia hills by the mars reconnaissance orbiter s compact reconnaissance imaging spectrometer crism hyperspectral imager 0 4 4 m is summarized we show that crism spectra are controlled by the proportion of ferric rich dust to ferrous bearing igneous minerals exposed in ripples and other wind blown deposits the evidence for aqueous alteration derived from spirit s data is associated with outcrops that are too small to be detected from orbital observations or with materials exposed from the shallow subsurface during rover activities although orbital observations show many other locations on mars with evidence for minerals formed or altered in an aqueous environment spirit s data imply that the older crust of mars has been altered even more extensively than evident from orbital data this result greatly increases the potential that the surface or shallow subsurface was once a habitable regime

thermal areas on kilauea and mauna loa volcanoes hawaii abstract active thermal areas are concentrated in three areas on mauna loa and three areas on kilauea high temperature fumaroles 115 362 c on mauna loa are restricted to the summit caldera whereas high temperature fumaroles on kilauea are found in the upper east rift zone mauna ulu summit fumaroles 562 c middle east rift zone 1977 eruptive fissure fumaroles and in the summit caldera solfataric activity that has continued for several decades occurs along border faults of kilauea caldera and at sulphur cone on the southwest rift zone of mauna loa solfataras that are only a few years old occur along recently active eruptive fissures in the summit caldera and along the rift zones of kilauea steam vents and hot air cracks also occur at the edges of cooling lava ponds on the summits of lava shields along faults and graben fractures and in diffuse patches that may reflect shallow magmatic intrusions

sedimentary silica on mars terrestrial planetary surfaces other than earth are overwhelmingly basaltic in character because of this among the most intriguing and significant results from recent studies of mars are the occurrences of high silica rocks at the pathfinder site and orbital thermal emission spectroscopy evidence for a global petrological dichotomy with andesites dominating the entire northern hemispheric plains however during the alteration of basalt under a wide variety of pressure temperature and fluid conditions silica is highly mobile and chemical and or mineralogical relationships among martian soils and other surface deposits suggest the likelihood that sedimentary silica phases would have formed during surficial alteration processes accordingly the redistribution of sedimentary silica needs to be considered in interpreting at least some of the high silica features seen on mars

mineralogy of three slightly palagonitized basaltic tephra samples from the summit of mauna kea hawaii certain palagonites from hawaii are considered to be among the best analogs for martian fines based upon similar spectral properties for this study three distinctly colored layers were sampled from slightly palagonitized basaltic tephra just below the summit of mauna kea at 4145 m elevation the mineralogy of size fractions of these samples was examined by diffuse reflectance visible and near ir and far ir spectroscopy optical microscopy x ray diffraction mossbauer spectroscopy magnetic analysis electron microprobe analysis empa and transmission and scanning electron microscopy for the 20 1000 m size fraction sample hwmk11 red is essentially completely oxidized and has a hematite ti hematite pigment dispersed throughout the silicate matrix the alteration is present throughout particle volumes and only a trace amount of glass is present no palagonitic rinds were detected in addition to ferric fe ti oxides other phases detected were plagioclase feldspar and a trace of olivine sample hwmk12 black has the lowest proportion of ferric bearing phases and is thus least weathered it consists mostly of unaltered glass with embedded plagioclase and minor amounts of pyroxene olivine and ti magnetite in some grains a thin palagonitic rind is visible indicating some surface alteration the mineralogy for sample hwmk13 yellow is the same as that for hwmk12 except that it has distinct well developed palagonitic rinds consisting of erionite and smectite for all samples the amount of glass and plagioclase decreases and the amount of smectite increases with decreasing particle size for size fractions 20 m for hwmk11 the amount of hematite is essentially constant and mica is present only in the coarse clay sized fraction smectites are low in structural fe for hwmk12 and hwmk13 the zeolite erionite is present along with smectites and nanophase ferric oxides np ox erionite abundance decreases and np ox abundance increases with decreasing particle size the smectite in both black and yellow samples contains some fe3 in octahedral layers there were only two mineral phases containing iron in the fine clay fraction namely smectites and iron oxides for hwmk11 relatively large iron oxide particles 0 1 to 0 4 m were dispersed on clay surfaces for hwmk12 and hwmk13 much finer np ox particles were present in lesser concentrations formation of the zeolite erionite is consistent with the arid climate zone where these samples were collected however transient hydrothermal processes that occurred during the eruption of mauna kea volcano under its permanent ice cap during the pleistocene may have resulted in minerals such as zeolites and smectites which may persist as relicts over a long period of time most of the iron released during weathering of basaltic tephra precipitated as poorly crystalline iron oxides and some of the fe has substituted for the octahedral cations in the structure of authigenic smectites the ti hematite in hwmk11 however is the result of high temperature oxidation of ti magnetite and exsolution from ironbearing silicate phases visible and near ir reflectivity spectra for the 20 m size fraction of hwmk11 is dominated by well crystalline ti hematite corresponding spectra for hwmk12 and hwmk13 whose ferric mineralogy is dominated by np ox particles are more similar to martian bright region spectra

rock coatings in hawaii basaltic lava flows exposed to semiarid weathering on the island of hawaii develop hydrous silica coatings that thicken and incorporate detrital material with age the nearly pure silica coatings on the younger rocks are colorless but basaltic detritus and its weathering products incorporated into coatings on older flows produce colors ranging from brown to red age rate of supply of material and the mechanical stability of flow surfaces dictate the color and thickness of coatings fresh glassy pahoehoe surfaces support thin as much as 5 m clear silica coatings but break down in a few years to expose the vesicular underlying material at first coloring is concentrated in the open vesicles yielding a dark brown color a mixture of red vesicles and projections of black basalt with age thicker accumulations of silica incorporate layers of oxidized basaltic material the dark basaltic material in kilauea and mauna kea coatings is probably supplied by large explosive eruptions but at mauna loa and kohala the source could be locally derived basaltic weathering products the clear hydrous silica layers are probably the product of leaching of locally derived basaltic dust

exploring for a record of ancient martian life the immediate task facing exopaleontology is to define a strategy to explore mars for a fossil record during the decade long exploration program that lies ahead consideration of the quality of paleontological information preserved under different geological conditions is important if we are to develop a strategy with broad applicability the preservation of microbial fossils is strongly influenced by the physical chemical and biological factors of the environment which acting together determine the types of information that will be captured and retained in the rock record in detrital sedimentary systems preservation is favored by rapid burial in fine grained clay rich sediments in chemical sedimentary systems preservation is enhanced by rapid entombment in fine grained chemical precipitates for long term preservation host rocks must be composed of stable minerals that are resistant to chemical weathering and that form an impermeable matrix and closed chemical system to protect biosignatures from alteration during subsequent diagenesis or metamorphism in this context host rocks composed of highly ordered chemically stable mineral phases like silica e g cherts or phosphate e g phosphorites are especially favored such lithologies tend to have very long crustal residence times and along with carbonates and shales are the most common host rocks for the precambrian microfossil record on earth although we make the defensible assumption that mars was more like the earth early in its history clearly the geological and historical differences between the two planets are many such differences must be carefully considered when adapting an earth based strategy to mars

hyperspectral reflectance mapping of cinder cones at the summit of mauna kea and implications for equivalent observations on mars 1 atmospherically corrected hyperspectral reflectance data 0 4 to 2 5 m derived from the airborne visible infrared imaging spectrometer aviris validated with field based traverses and laboratory analyses were used to map the distribution of ferric oxide sulfate and phyllosilicate minerals exposed on fresh and altered cones on the summit of mauna kea volcano hawaii spectra from 0 4 to 1 1 m exhibit charge transfer and electronic transition features related to hematite nanophase iron oxide and possibly jarosite whereas spectra from 2 0 to 2 5 m are characterized by cation oh features related to kaolinite montmorillonite and saponite unaltered cones exhibit concentric zoning of iron oxide signatures with crystalline hematite located near the summits and nanophase iron oxide signatures found at the base of cones and on flow surfaces altered cones puu poliahu and puu waiau have exposures of three phyllosilicate and possible jarosite units in some cases there is zoning with a core of saponite surrounded by montmorillonite kaolinite is only found in two exposures on puu poliahu with one exposure coinciding with a possible jarosite unit the relatively small spatial scale associated with alteration zones seen on mauna kea demonstrates the importance of obtaining high spatial resolution hyperspectral observations of mars

controls on palagonitization versus pedogenic weathering of basaltic tephra evidence from the consolidation and geochemistry of the keanakako i ash member kilauea volcano 1 on the summit of kilauea volcano incipient palagonitization and consolidation of vitric tephras from the 90 of the carbon is mantle derived we hypothesize that the palagonitized zones may denote the location of fossil steam vents similar to active vents exposed along circumferential faults on both the north and the south sides of the kilauea caldera elsewhere keanakako i tephras are weathering into pedogenic products that closely reflect modern environmental conditions under acidic soil conditions ph 6 0 tephra is undergoing dissolution with the development of opaline crusts on outcrop faces under more neutral soil ph 6 5 7 8 the pedogenic products reflect the degree of desilication of tephra mitigated by leaching dominantly smectite where mean annual rainfall is 50 cm yr and dominantly kaolinite allophane and or imogolite where rainfall exceeds 250 cm yr

visible near infrared and middle infrared spectroscopy of altered basaltic tephras spectral signatures of phyllosilicates sulfates and other aqueous alteration products with application to the mineralogy of the columbia hills of gusev crater mars 1 we studied visible to near infrared vnir 0 35 2 5 m and middle infrared mir 1800 250 cm 1 also called thermal infrared and vibrational spectra of basaltic tephras from mauna kea volcano that were altered under ambient hydrothermal hydrolytic and acid sulfate and dry heat conditions although models of mir spectra of altered tephras generally produce fits whose quality is reduced compared to deconvolutions of primary lithologies they successfully identify major alteration phases cristobalite oxide phyllosilicate and sulfate except in palagonites mir spectra of the 1 in spectra of the 500 1000 m fraction only if phyllosilicates are present although mauna kea palagonitic tephra is considered a vnir analog to martian dust comparison of mir altered tephra spectra 45 m fraction to dust spectra retrieved from mars global surveyor and mars exploration rover instruments do not provide good spectral matches the best mir match is a tephra that has a strong plagioclase feldspar transparency feature and was altered under dry high temperature oxidizing conditions this sample is not a vnir analog and is not a process analog but it emphasizes the mineralogical importance of plagioclase feldspar in martian dust no single tephra is a good spectral analog across the vnir and mir we found no evidence for substantial sulfates or phyllosilicates in mini thermal emission spectrometer mini tes spectra from gusev crater

opaline silica in young deposits on mars high spatial and spectral resolution reflectance data acquired by the mars reconnaissance orbiter compact reconnaissance imaging spectrometer for mars crism instrument reveal the presence of h 2o and sioh bearing phases on the martian surface the spectra are most consistent with opaline silica and glass altered to various degrees confirming predictions based on geochernicall experiments and models that amorphous silica should be a common weathering product of the basaltic martian crust these materials are associated with hydrated fe sulfates including h 3o bearing jarosite and are found in finely stratified deposits exposed on the floor of and on the plains surrounding the valles marineris canyon system stratigraphic relationships place the formation age of these deposits in the late hesperian or possibly the amazonian implying that aqueous alteration continued to be an important and regionally extensive process on mars during that time

spectral reflectance and morphologic correlations in eastern terra meridiani mars the mars express observatoire pour la mineralogie l9eau les glaces et l9activite omega hyperspectral image data covering eastern terra meridiani indicate the ubiquitous presence of molecular water in etched terrain materials that disconformably overlie heavily cratered terrains and underlie the hematite bearing plains explored by the opportunity rover identification of crystalline water in kieserite mgso4 h2o is linked to materials exposed in a valley and plateau to the north of hematite bearing plains the mineralogical similarities between the etched terrain deposits examined with omega data and the layered rocks examined by opportunity imply that the ancient aqueous environments inferred from analyses of the rover data extend over regional scales

alteration processes in volcanic soils and identification of exobiologically important weathering products on mars using remote sensing determining the mineralogy of the martian surface material provides information about the past and present environments on mars which are an integral aspect of whether or not mars was suitable for the origin of life mineral identification on mars will most likely be achieved through visible infrared remote sensing in combination with other analyses on landed missions therefore understanding the visible and infrared spectral properties of terrestrial samples formed via processes similar to those thought to have occurred on mars is essential to this effort and will facilitate site selection for future exobiology missions to mars visible to infrared reflectance spectra are presented here for the fine grained fractions of altered tephra lava from the haleakala summit basin on maui the tarawera volcanic complex on the northern island of new zealand and the greek santorini island group these samples exhibit a range of chemical and mineralogical compositions where the primary minerals typically include plagioclase pyroxene hematite and magnetite the kind and abundance of weathering products varied substantially for these three sites due in part to the climate and weathering environment the moist environments at santorini and tarawera are more consistent with postulated past environments on mars while the dry climate at the top of haleakala is more consistent with the current martian environment weathering of these tephra is evaluated by assessing changes in the leachable and immobile elements and through detection of phyllosilicates and iron oxide oxyhydroxide minerals identifying regions on mars where phyllosilicates and many kinds of iron oxides oxyhydroxides are present would imply the presence of water during alteration of the surface material tephra samples altered in the vicinity of cinder cones and steam vents contain higher abundances of phyllosilicates iron oxides and sulfates and may be interesting sites for exobiology

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

uppermost mantle pn velocity model for the afar region ethiopia an insight into rifting processes the afar depression ethiopia offers unique opportunities to study the transition from continental rifting to oceanic spreading because the process is occurring onland using traveltime tomography and data from a temporary seismic deployment we describe the first regional study of uppermost mantle p wave velocities vpn we find two separate low vpn zones as low as 7 2 km s 1 beneath regions of localized thinned crust in northern afar indicating the existence of high temperatures and potentially partial melt the zones are beneath and off axis from contemporary crustal magma intrusions in active magmatic segments the dabbahu manda hararo and erta ale segments this suggests that these intrusions can be fed by off axis delivery of melt in the uppermost mantle and that discrete areas of mantle upwelling and partial melting thought to characterize segmentation of the uppermost mantle at seafloor spreading centres are initiated during the final stages of break up

geochemical and mineralogical indicators for aqueous processes in the columbia hills of gusev crater mars 1 water played a major role in the formation and alteration of rocks and soils in the columbia hills the extent of alteration ranges from moderate to extensive five distinct rock compositional classes were identified the order for degree of alteration is watchtower clovis wishstone peace backstay the rover s wheels uncovered one unusual soil paso robles that is the most s rich material encountered clovis class rocks have compositions similar to gusev plains soil but with higher mg cl and br and lower ca and zn watchtower and wishstone classes have high al ti and p and low cr and ni peace has high mg and s and low al na and k backstay basalts have high na and k compared to plains adirondack basalts and paso robles soil has high s and p some rocks are corundum normative indicating that their primary compositions were changed by loss and or gain of rock forming elements clovis materials consist of magnetite nanophase ferric oxides npox hematite goethite ca phosphates ca and mg sulfates pyroxene and secondary aluminosilicates wishstone and watchtower rocks consist of fe oxides oxyhydroxides ilmenite ca phosphate pyroxene feldspar mg sulfates and secondary aluminosilicates peace consists of magnetite npox mg and ca sulfates pyroxene olivine feldspar apatite halides and secondary aluminosilicates paso robles consists of fe3 mg ca and other sulfates ca phosphates hematite halite allophane and amorphous silica columbia hills outcrops and rocks may have formed by the aqueous alteration of basaltic rocks volcaniclastic materials and or impact ejecta by solutions that were rich in acid volatile elements

effects of fractures on seismic wave velocity and attenuation the effects of fractures on the seismic velocity and attenuation of a rock are investigated using theoretical results and experimental data fractures in a rock mass influence the traveltimes and amplitudes of seismic waves that have propagated through them the displacement discontinuity model recently employed in fracture investigations is modified to describe the effect of fractures on seismic wave velocity and attenuation this new model the modified displacement discontinuity model mdd is formulated in a way analogous to transmission line analysis the fractures are treated as transmission lines for the passage of seismic waves the mdd takes into consideration realistic fracture parameters which include the fracture length the fractional area of a fracture surface in contact and the nature of the infilling material a single fracture of varying geometric and material properties is shown to affect dramatically the transmission properties of a propagating waveform and hence the seismic velocity and attenuation these effects have been shown to result in a frequency dependent velocity and attenuation the sensitivity of the fracture parameters to seismic wave velocity and attenuation was investigated and interesting results were obtained fracture parameters used in designing experimental models consisting of synthetically manufactured cracks were fed into the mdd and a well known crack model hudson s model for comparison velocities as a function of the incident wave angle were obtained from both numerical models and were compared with the results from the experimental modelling for p waves the mdd model results show better agreement with those of the experimental model for all crack densities investigated than those from hudson s model

stripping of keanakakoi tephra on kilauea volcano hawaii morphological characteristics erosional processes and effects of burial and exhumation by debris mantles on basaltic volcanic landforms have been evaluated through field study of the keanakakoi formation a basaltic tephra formed in 1790 by phreato magmatic eruptions from kilauea caldera hawaii the upper coarse lithic intermediate fine vitric and lower mixed members of this formation play different roles in the creation of micro terrain elements during stripping of tephra from the underlying bedrock of the seven micro terrain elements defined bedrock scabby upland surfaces and lag gravels are the most distinctive and widely distributed different proportions and combinations of micro terrain elements define five zones of progressive deterioration of the keanakakoi tephra blanket southwestward from kilauea caldera into the kau desert fluvial and eolian processes operate on different time scales and at different locations governed by blanket thickness debris caliber and the formation of case hardened crusts stripping of an entire mantle is probably not possible however materials trapped within depressions form the only clearly discernible morphological expression of previously more extensive debris blankets

characterization of phyllosilicates observed in the central mawrth vallis region mars their potential formational processes and implications for past climate mawrth vallis contains one of the largest exposures of phyllosilicates on mars nontronite montmorillonite kaolinite and hydrated silica have been identified throughout the region using data from the compact reconnaissance imaging spectrometer for mars crism in addition saponite has been identified in one observation within a crater these individual minerals are identified and distinguished by features at 1 38 1 42 1 91 and 2 17 2 41 m there are two main phyllosilicate units in the mawrth vallis region the lowermost unit is nontronite bearing unconformably overlain by an al phyllosilicate unit containing montmorillonite plus hydrated silica with a thin layer of kaolinite plus hydrated silica at the top of the unit these two units are draped by a spectrally unremarkable capping unit smectites generally form in neutral to alkaline environments while kaolinite and hydrated silica typically form in slightly acidic conditions thus the observed phyllosilicates may reflect a change in aqueous chemistry spectra retrieved near the boundary between the nontronite and al phyllosilicate units exhibit a strong positive slope from 1 to 2 m likely from a ferrous component within the rock this ferrous component indicates either rapid deposition in an oxidizing environment or reducing conditions formation of each of the phyllosilicate minerals identified requires liquid water thus indicating a regional wet period in the noachian when these units formed the two main phyllosilicate units may be extensive layers of altered volcanic ash other potential formational processes include sediment deposition into a marine or lacustrine basin or pedogenesis

silica in a mars analog environment ka u desert kilauea volcano hawaii airborne visible near infrared imaging spectrometer aviris data acquired over the ka u desert are atmospherically corrected to ground reflectance and used to identify the mineralogic components of relatively young basaltic materials including 250 700 and 200 400 year old lava flows 1971 and 1974 flows ash deposits and solfatara incrustations to provide context a geologic surface units map is constructed verified with field observations and supported by laboratory analyses aviris spectral end members are identified in the visible 0 4 to 1 2 m and short wave infrared 2 0 to 2 5 m wavelength ranges nearly all the spectral variability is controlled by the presence of ferrous and ferric iron in such minerals as pyroxene olivine hematite goethite and poorly crystalline iron oxides or glass a broad nearly ubiquitous absorption feature centered at 2 25 m is attributed to opaline amorphous hydrated silica and is found to correlate spatially with mapped geologic surface units laboratory analyses show the silica to be consistently present as a deposited phase including incrustations downwind from solfatara vents cementing agent for ash duricrusts and thin coatings on the youngest lava flow surfaces a second ti rich upper coating on young flows also influences spectral behavior this study demonstrates that secondary silica is mobile in the ka u desert on a variety of time scales and spatial domains the investigation from remote field and laboratory perspectives also mimics exploration of mars using orbital and landed missions with important implications for spectral characterization of coated basalts and formation of opaline silica in arid acidic alteration environments

mars reconnaissance orbiter observations of light toned layered deposits and associated fluvial landforms on the plateaus adjacent to valles marineris abstract we have used data from the mars reconnaissance orbiter to study 30 80 m thick light toned layered deposits on the plateaus adjacent to valles marineris at five locations 1 south of ius chasma 2 south of western melas chasma 3 south of western candor chasma 4 west of juventae chasma and 5 west of ganges chasma the beds within these deposits have unique variations in brightness color mineralogy and erosional properties that are not typically observed in light toned layered deposits within valles marineris or many other equatorial areas on mars reflectance spectra indicate these deposits contain opaline silica and fe sulfates consistent with low temperature acidic aqueous alteration of basaltic materials we have found valley or channel systems associated with the layered deposits at all five locations and the volcanic plains adjacent to juventae ius and ganges exhibit inverted channels composed of light toned beds valleys channels and light toned layering along the walls of juventae and melas chasmata are most likely coeval to the aqueous activity that affected the adjacent plateaus and indicate some hydrological activity occurred after formation of the chasmata although the source of water and sediment remains uncertain the strong correlation between fluvial landforms and light toned layered deposits argues for sustained precipitation surface runoff and fluvial deposition occurring during the hesperian on the plateaus adjacent to valles marineris and along portions of chasmata walls

origin development and chemistry of silica alumina rock coatings from the semi arid regions of the island of hawaii abstract exposed rock surfaces in the semi arid regions of the island of hawaii are characterized by an x ray amorphous silica alumina surface coating ranging in thickness from a few to several hundred micrometers these coatings are composed of clear to translucent white lamellae of amorphous silica with a minor component of some amorphous aluminum phase and in some cases interlayered fine grained clastic material the coatings are derived from exogenous material both the amorphous silica alumina component and the clastic component of the coating are derived locally description of the chemical composition mineralogy and the morphology of the coating along with an evaluation of possible sources enables formulation of a model which describes their development because the composition and mineralogy of the coatings is dissimilar from all likely source materials direct incorporation of the source material could not account for the coating instead fine grained clastic material locally derived from the soil is blown onto the rock surface during a later non violent wetting event such as fog or dew some of this material goes into solution as this solution is evaporated poorly ordered mineral phases precipitate onto the rock surface forming the coating some of the clastic material is incorporated into the coating during the precipitation late stage precipitates are removed during later more dynamic wetting events such as a heavy rainfall which wash across the rock surface