spectral mineralogical and geochemical variations across home plate gusev crater mars indicate high and low temperature alteration over the last 3 years in gusev crater mars the spirit rover observed coherent variations in color mineralogy and geochemistry across home plate an 80 m diameter outcrop of basaltic tephra observations of home plate from orbit and from the summit of husband hill reveal clear differences in visible near infrared vnir colors between its eastern and western regions that are consistent with mineralogical compositions indicated by mossbauer spectrometer mb and by miniature thermal emission spectrometer mini tes pyroxene and magnetite dominate the east side while olivine nanophase fe oxide npox and glass are more abundant on the western side alpha particle x ray spectrometer apxs observations reveal that eastern home plate has higher si mg al zn ni and k while cl and br are higher in the west we propose that these variations are the result of two distinct alteration regimes that may or may not be temporally related a localized higher temperature recrystallization and alteration of the east side of home plate and lower temperature alteration of the western side that produced npox

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

spectrophotometric properties of materials observed by pancam on the mars exploration rovers 3 sols 500 1525 abstract the panoramic camera pancam on the mars exploration rovers spirit and opportunity acquired visible near infrared 432 1009 nm multispectral observations of soils and rocks under varying viewing and illumination geometries data retrieved from these images were modeled using radiative transfer theory to study the microphysical and surface scattering nature of materials at both sites nearly 57 000 individual measurements from 1900 images were collected of rock and soil units identified by their color and morphologic properties over a wide range of phase angles 0 150 images were acquired between sols 500 and 1525 in the columbia hills and regions around home plate in gusev crater and in the plains and craters between erebus and victoria craters in meridiani planum corrections for diffuse skylight incorporated sky models based on observations of atmospheric opacity throughout the mission disparity maps created from pancam stereo images allowed estimates of local facet orientations for spirit soils at lower elevations near home plate were modeled with lower single scattering albedo w values than those on the summit of husband hill but otherwise soils exhibited similar scattering properties to previous gusev soils dark ripple sands at the el dorado dunes were among the most forward scattering materials modeled silica rich soils and nodules near home plate were analyzed for the first time and exhibited increased forward scattering behavior with increasing wavelength consistent with microporosity inferred from previous high resolution images and thermal infrared spectroscopy for opportunity the opposition effect width parameter for sandstone outcrop rocks was modeled for the first time and demonstrated average values consistent with surfaces of intermediate porosity and or grain size distribution between those modeled for spherule rich soils and darker clast poor soils soils outside a wind streak emanating from the northern rim of victoria crater exhibited w values 16 higher than soils inside the streak overall w values and scattering properties for outcrop rocks spherule rich soils and rover tracks were similar to previous meridiani planum analyses emphasizing the homogeneity of these materials across nearly 12 km of rover odometry

oxygen isotope calibration of the onset of ice rafting and history of glaciation in the north atlantic region we report here that dsdp site 552a cored with the hydraulic piston corer on the west flank of rockall bank recovered an undisturbed sequence of alternating white deep sea carbonate oozes and dark coloured layers that are rich in glacial debris oxygen isotope analysis of the sequence together with detailed nannofossil and palaeomagnetic stratigraphy shows that the first major horizon of ice rafting occurred at about 2 4 myr and was preceded by a minor pulse of ice rafting at about 2 5 myr the carbon isotope record shows that the site has been bathed by a water mass of similar characteristics to present day north atlantic deep water at least since 3 5 myr

inferred glacio eustatic control for high frequency depositional sequences of the plio pleistocene kazusa group a forearc basin fill in boso peninsula japan abstract the plio pleistocene forearc basin fill of the kazusa group as much as 3000 m thick is represented by a series of marine environments ranging from deep sea basin plain to shallow sea it developed during about 2 4 to 0 45 ma and is well exposed in the boso peninsula japan chronostratigraphic resolution of the kazusa group is partly within about 0 05 m y based on the combination of fission track dating of volcanic ash layers and bio and magneto stratigraphy many volcanic ash layers are intercalated in the kazusa group and provide distinct chronostratigraphic surfaces within the heterogeneous lithologies detailed outcrop studies on depositional facies discontinuities and lateral terminations of volcanic ash layers allow high resolution sequence stratigraphic interpretation of the kazusa group seventeen depositional sequences were identified in the kazusa group each depositional sequence was tentatively correlated with the stable oxygen isotope sea level index integrated with the age framework of the kazusa group this correlation indicates that frequencies of the depositional sequences can be estimated to be in the range of 0 2 0 02 m y and are within fourth and fifth order stratigraphic cyclicities depositional sequences constitute third order transgressive and highstand sequence sets and the kazusa group is interpreted to represent a third order composite sequence with a duration of about 1 95 m y development of the third order composite sequence was also controlled by an overall rise and fall of glacio eustatic sea levels overprinted by tectonic events related to fluctuations in oceanic plate motion which occurred at about 2 6 ma and 0 5 ma respectively

light toned salty soils and coexisting si rich species discovered by the mars exploration rover spirit in columbia hills 1 light toned soils were exposed through serendipitous excavations by spirit rover wheels at eight locations in the columbia hills their occurrences were grouped into four types on the basis of geomorphic settings at three major exposures the light toned soils are hydrous and sulfate rich the spatial distributions of distinct types of salty soils vary substantially with centimeter scaled heterogeneities at paso robles dead sea shredded and champagne penny a well mixed nature for light toned soils occurring near and at the summit of husband hill and relatively homogeneous distributions in the two layers at the tyrone site aeolian fumarolic and hydrothermal fluid processes are suggested to be responsible for the deposition transportation and accumulation of these light toned soils in addition a change in pancam spectra of tyrone yellowish soils was observed after being exposed to current martian surface conditions for 175 sols this change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface si rich nodules and soils were observed near the major exposures of s rich soils they possess a characteristic feature in pancam visible near infrared vis nir spectra that may be diagnostic of hydrated species and this spectral feature can be used to search for additional si rich species the exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the neutron spectrometer on mars odyssey

rocks of the columbia hills 1 the mars exploration rover spirit has identified five distinct rock types in the columbia hills of gusev crater clovis class rock is a poorly sorted clastic rock that has undergone substantial aqueous alteration we interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials wishstone class rock is also a poorly sorted clastic rock that has a distinctive chemical composition that is high in ti and p and low in cr wishstone class rock may be pyroclastic or impact in origin peace class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of mg and ca sulfates peace class rock may have formed when water briefly saturated the ultramafic sands and evaporated to allow precipitation of the sulfates watchtower class rocks are similar chemically to wishstone class rocks and have undergone widely varying degrees of near isochemical aqueous alteration they may also be ejecta deposits formed by impacts into wishstone rich materials and altered by small amounts of water backstay class rocks are basalt trachybasalt lavas that were emplaced in the columbia hills after the other rock classes were either as impact ejecta or by localized volcanic activity the geologic record preserved in the rocks of the columbia hills reveals a period very early in martian history in which volcanic materials were widespread impact was a dominant process and water was commonly present

rock spectral classes observed by the spirit rover s pancam on the gusev crater plains and in the columbia hills 1 this paper examines the ferrous and ferric iron mineralogy of rocks inferred from 246 visible near infrared 430 1010 nm multispectral observations made by the mars exploration rover spirit s pancam on its traverse from its landing site to its second winter haven location principal component correspondence analyses and a sequential maximum angle convex cone technique were used to identify 14 candidate classes spectra from the west spur of husband hill and the watchtower area had the highest 535 and 601 nm band depths indicating that these areas were more oxidized differences in the depth and band center of a near infrared nir absorption feature were observed using 904 nm band depth and 803 904 nm ratio and parameters gauging the 754 864 and 754 1009 nm slopes spectra of rocks from the southern flank of husband hill had negative 754 1009 nm slopes and a broad nir absorption consistent with high olivine abundances rocks observed on the lower west spur at the cumberland ridge locale at the husband hill summit and at the haskin ridge locale had deep 904 nm band depths and steep 754 864 nm slopes consistent with greater pyroxene abundances these observations are consistent with results on iron bearing mineralogy from spirit s mossbauer spectrometer comparisons of these rock spectral classes with a set of terrestrial analog samples found similarities between the west spur and watchtower classes and red hematite bearing impact melts fewer similarities were found in comparisons of the columbia hills classes with basaltic hydrovolcanic tephras

oxygen isotopes and sea level from the time that detailed oxygen isotope records derived from foraminifera living in the constant temperature environment of the abyssal ocean became available there has been a discrepancy between the ice volume record that these records imply and that derived from the altitude of dated coral terraces around the world here we re examine the data and conclude that the temperature of the abyssal ocean has been an actively varying component of the climate system

distribution and seismic facies of mississippi fan channels analysis of a closely spaced grid of multifold seismic data across the upper pliocene pleistocene mississippi fan in the deep gulf of mexico allows for the first time a detailed description of a large part of the fan mapping of the 17 channel levee systems show considerable variability in parameters such as size location geometry lateral migration aggradation sinuosity and downfan bifurcation which suggests that multiple factors control channel evolution the youngest channel cored during deep sea drilling project leg 96 refects only style in channel evolution such complexity in large mud dominated submarine fan systems must be considered in evaluating fan models and interpreting ancient fan systems

alteration of hydrovolcanic basaltic ash observations with visible and near infrared spectrometry ash of basaltic composition that is produced by hydrovolcanic activity occurs frequently on earth and may be much more widespread on mars altered basaltic tephras from tuff rings and tuff cones across the basin and range were examined using visible and near infrared vis ir reflectance spectrometry and a variety of other techniques it was found that vis ir spectrometry is sensitive to subtle changes in the hydration and oxidation state of these tephras hydration produces an increase in overall reflectance with gradual development of water and hydroxyl absorptions at 1 4 m and 1 9 m the oxidation of basaltic tephras can be observed spectrally through changes in the position and slope of the fe3 o2 charge transfer edge inflections on that edge due to ferric oxide minerals and changes in the position and depth of the 1 m iron crystal field band significantly in the tuffs examined ferrous and ferric iron minerals produce one composite absorption feature rather than two resolvable bands different styles of alteration were noted between thinly bedded tuff ring deposits emplaced by high energy largely dry pyroclastic surge and massively bedded tuff cone deposits emplaced by wetter lower energy pyroclastic flow the former class of tephras become hydrated and only moderately oxidized with some limited development of dioctahedral smectite clay minerals and minimal palagonitization the latter class of tephras are highly palagonitized which implies a high degree of hydration and oxidation in fact in the most highly altered tephras all the fe2 that is initially in the volcanic glass is converted to fe3 within nanophase and bulk ferric oxide phases in the palagonite there is also more extensive development in the tuff cone beds of zeolite and phyllosilicate minerals the differences in reflectance spectra of altered basaltic tephras can be traced back to initial differences in the water magma ratio extant at the volcanic vent thus vis ir spectrometry holds the potential to be used as a tool for investigations into the volcanic history and paleoclimate of volcanic terrains

remote detection of past habitability at mars analogue hydrothermal alteration terrains using an exomars panoramic camera emulator abstract a major scientific goal of the european space agency s exomars 2018 rover is to identify evidence of life within the martian rock record key to this objective is the remote detection of geological substrates that are indicative of past habitable environments which will rely on visual stereo wide angle and high resolution images and multispectral 440 1000 nm data produced by the panoramic camera pancam instrument we deployed a pancam emulator at four hydrothermal sites in the namafjall volcanic region of iceland a mars analogue hydrothermal alteration terrain at these sites sustained acidic neutral aqueous interaction with basaltic substrates crystalline and sedimentary has produced phyllosilicate ferric oxide and sulfate rich alteration soils and secondary mineral deposits including gypsum veins and zeolite amygdales pancam emulator datasets from these sites were complemented with i nerc airborne research and survey facility aerial hyperspectral images of the study area ii in situ reflectance spectroscopy 400 1000 nm of pancam spectral targets iii laboratory x ray diffraction and iv laboratory vnir 350 2500 nm spectroscopy of target samples to identify their bulk mineralogy and spectral properties the mineral assemblages and palaeoenvironments characterised here are analogous to neutral acidic alteration terrains on mars such as at mawrth vallis and gusev crater combined multispectral and high resolution camera datasets were found to be effective at capturing features of astrobiological importance such as secondary gypsum and zeolite mineral veins and phyllosilicate rich substrates our field observations with the pancam emulator also uncovered stray light problems which are most significant in the nir wavelengths and investigations are being undertaken to ensure that the flight model pancam cameras are not similarly affected

mapping the distribution of mine tailings in the coeur d alene river valley idaho through the use of a constrained energy minimization technique abstract ferruginous fluvial sediments deposited on the banks and on the floodplain of the coeur d alene river in northern idaho have been contaminated by trace metals released by mining activities in and around the town of kellogg idaho these ferruginous sediments are amenable to detection and mapping by remotely sensed data data collected by the airborne visible infrared imaging spectrometer aviris were analyzed both to map exposed concentrations of these sediments and also to consider their mineralogic variability the processing tool used to map the ferruginous sediments was the recently developed constrained energy minimization cem technique which on a pixel by pixel basis maximizes the response of the target signature and suppresses the response of undesired background signatures cem abundance images produced using both laboratory and image data as the target signatures were thresholded to produce a set of spectra dominated by the ferruginous sediment spectral response spectral subsections of this data set were analyzed using principal components analysis and endmember image spectra representing in most cases known mineral phases were identified

migration pathways of the late campanian and maastrichtian shallow facies ammonite sphenodiscus in north america abstract records of the ammonites sphenodiscus lobatus and s phenodiscus pleurisepta from the latest cretaceous gulf of mexico region the western interior seaway and the atlantic coast have repeatedly been used as a stratigraphic index for a maastrichtian age in recent years however high resolution biostratigraphy on north eastern mexican occurrences and its combination with other correlation tools such as sequence stratigraphy as well as a refined position of the campanian maastrichtian boundary led to a different interpretation regarding the age of the earliest sphenodiscus the wealth of data allows us to reconstruct their routes of dispersal over the north american continent migration appears to have been directed from south to north and is thus opposed to that of baculites ovatus dispersal of all three species is clearly related to changes in the maastrichtian sea level

the evolution of pleistocene climate a time series approach abstract in the later part of the pleistocene variations in global ice volume have been dominated by an approximate 100 000 year cycle analysis of 2 myr long oxygen isotope record from an equatorial pacific core indicates that this is true only for the last 900 000 years prior to this time the amplitude of the 100 000 year cycle is much reduced as is the variance of all oscillations with periods greater than 60 000 years based on results of time series analysis of this 2 myr long record the pleistocene glacial cycles can be divided into three sections 1 the late pleistocene 0 900 kyr b p where the variations in the isotope record are dominated by the 100 000 year cycle 2 the middle pleistocene 900 1450 kyr b p in which low frequency components are not as important as in the later period of the pleistocene and 3 the early pleistocene late pliocene 1450 2000 kyr b p where general reductions of importance at all frequencies is seen as compared to the later intervals recent modeling efforts which describe variations in global ice volume show that the dominant low frequency component observed in the late pleistocene can result from different time constants for the rate of glacial growth and decay in response to variations in the earth s orbital parameters it is hypothesized that during the early pleistocene the rate of growth and decay of glaciers were more similar and that continental erosion by successive glacial advances lowered the land surface in areas of ice cap formation to below sea level when the ice caps became marine based more rapid decay of the ice became possible

hematite pyroxene and phyllosilicates on mars implications from oxidized impact melt rocks from manicouagan crater quebec canada visible and near ir reflectivity mossbauer and x ray diffraction data were obtained on powders of impact melt rock from the manicouagan impact crater located in quebec canada the iron mineralogy is dominated by pyroxene for the least oxidized samples and by hematite for the most oxidized samples phyllosilicate smectite contents up to 15 wt were found in some heavily oxidized samples nanophase hematite and or paramagnetic ferric iron is observed in all samples no hydrous ferric oxides e g goethite lepidocrocite and ferrihydrite were detected which implies the alteration occurred above 250 c oxidative alteration is thought to have occurred predominantly during late stage crystallization and subsolidus cooling of the impact melt by invasion of oxidizing vapors and or solutions while the impact melt rocks were still hot the near ir band minimum correlated with the extent of aleration fe3 fetot and ranged from 1000 nm high ca pyroxene to 850 nm bulk well crystalline hematite for least and most oxidized samples respectively intermediate band positions 900 920 nm are attributed to low ca pyroxene and or a composite band from hematite pyroxene assemblages manicouagan data are consistent with previous assignments of hematite and pyroxene to the 850 and 1000 nm bands observed in martian reflectivity spectra manicouagan data also show that possible assignments for intermediate band positions 900 920 nm in martian spectra are pyroxene and or hematite pyroxene assemblages by analogy with impact melt sheets and in agreement with observables for mars oxidative alteration of martian impact melt sheets above 250 c and subsequent erosion could produce rocks and soils with variable proportions of hematite both bulk and nanophase pyroxene and phyllosilicates as iron bearing mineralogies if this process is dominant these phases on mars were formed rapidly at relatively high temperatures on a sporadic basis throughout the history of the planet the manicouagan samples also show that this mineralogical diversity can be accomplished at constant chemical composition which is also indicated for mars from analyses of soil at the two viking landing sites

mossbauer mineralogy of rock soil and dust at gusev crater mars spirit s journey through weakly altered olivine basalt on the plains and pervasively altered basalt in the columbia hills 1 the mossbauer spectrometer on spirit measured the oxidation state of fe identified fe bearing phases and measured relative abundances of fe among those phases for surface materials on the plains and in the columbia hills of gusev crater eight fe bearing phases were identified olivine pyroxene ilmenite magnetite nanophase ferric oxide npox hematite goethite and a fe3 sulfate adirondack basaltic rocks on the plains are nearly unaltered fe3 fet px and minor npox and magnetite columbia hills basaltic rocks are nearly unaltered peace and backstay moderately altered woolypatch wishstone and keystone and pervasively altered e g clovis uchben watchtower keel and paros with fe3 fet 0 6 0 9 fe from pyroxene is greater than fe from olivine ol sometimes absent and fe2 from ol px is 40 49 and 9 24 for moderately and pervasively altered materials respectively ilmenite fe from ilm 3 6 is present in backstay wishstone keystone and related rocks along with magnetite fe from mt 10 15 remaining fe is present as npox hematite and goethite in variable proportions clovis has the highest goethite content fe from gt 40 goethite feooh is mineralogical evidence for aqueous processes because it has structural hydroxide and is formed under aqueous conditions relatively unaltered basaltic soils fe3 fet 0 3 occur throughout gusev crater 60 80 fe from ol px 10 30 from npox and 10 from mt pasorobles soil in the columbia hills has a unique occurrence of high concentrations of fe3 sulfate 65 of fe magnetite is identified as a strongly magnetic phase in martian soil and dust

field reconnaissance geologic mapping of the columbia hills mars based on mars exploration rover spirit and mro hirise observations chemical mineralogic and lithologic ground truth was acquired for the first time on mars in terrain units mapped using orbital mars reconnaissance orbiter s high resolution imaging science experiment mro hirise image data examination of several dozen outcrops shows that mars is geologically complex at meter length scales the record of its geologic history is well exposed stratigraphic units may be identified and correlated across significant areas on the ground and outcrops and geologic relationships between materials may be analyzed with techniques commonly employed in terrestrial field geology despite their burial during the course of martian geologic time by widespread epiclastic materials mobile fines and fall deposits the selective exhumation of deep and well preserved geologic units has exposed undisturbed outcrops stratigraphic sections and structural information much as they are preserved and exposed on earth a rich geologic record awaits skilled future field investigators on mars the correlation of ground observations and orbital images enables construction of a corresponding geologic reconnaissance map most of the outcrops visited are interpreted to be pyroclastic impactite and epiclastic deposits overlying an unexposed substrate probably related to a modified gusev crater central peak fluids have altered chemistry and mineralogy of these protoliths in degrees that vary substantially within the same map unit examination of the rocks exposed above and below the major unconformity between the plains lavas and the columbia hills directly confirms the general conclusion from remote sensing in previous studies over past years that the early history of mars was a time of more intense deposition and modification of the surface although the availability of fluids and the chemical and mineral activity declined from this early period significant later volcanism and fluid convection enabled additional if localized chemical activity

iron mineralogy and aqueous alteration from husband hill through home plate at gusev crater mars results from the mossbauer instrument on the spirit mars exploration rover 1 spirit s mossbauer mb instrument determined the fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the gusev plains and the columbia hills west spur husband hill haskin ridge northern inner basin and home plate on mars the plains are predominantly float rocks and soil derived from olivine basalts outcrops at west spur and on husband hill have experienced pervasive aqueous alteration as indicated by the presence of goethite olivine rich outcrops in a possible mafic ultramafic horizon are present on haskin ridge relatively unaltered basalt and olivine basalt float rocks occur at isolated locations throughout the columbia hills basalt and olivine basalt outcrops are found at and near home plate a putative hydrovolcanic structure at least three pyroxene compositions are indicated by mb data mb spectra of outcrops barnhill and torquas resemble palagonitic material and thus possible supergene aqueous alteration deposits of fe3 sulfate soil located at paso robles arad and tyrone are likely products of acid sulfate fumarolic and or hydrothermal activity possibly in connection with home plate volcanism hematite rich outcrops between home plate and tyrone e g montalva may also be products of this aqueous activity low water to rock ratios isochemical alteration are implied during palagonite goethite and hematite formation because bulk chemical compositions are basaltic so3 free basis high water to rock ratios leaching under acid sulfate conditions are implied for the high sio2 rock and soil in eastern valley and the float rock fuzzysmith which has possible pyrite marcasite as a hydrothermal alteration product

geologic context of in situ rocky exposures in mare serpentis mars implications for crust and regolith evolution in the cratered highlands abstract global acquisition of infrared spectra and high resolution visible and infrared imagery has enabled the placement of compositional information within stratigraphic and geologic context mare serpentis a low albedo region located northwest of hellas basin is rich in spectral and thermophysical diversity and host to numerous isolated exposures of in situ rocky material most martian surfaces are dominated by fine grained particulate materials that bear an uncertain compositional and spatial relationship to their source thus location and characterization of in situ rock exposures is important for understanding the origin of highland materials and the processes which have modified those materials using spectral thermophysical and morphologic information we assess the local and regional stratigraphy of the mare serpentis surface in an effort to reconstruct the geologic history of the region the martian highlands in mare serpentis are dominated by two interspersed surface units which have distinct compositional and thermophysical properties 1 rock dominated surfaces relatively enriched in olivine and pyroxene and depleted in high silica phases and 2 sediment or indurated material depleted in olivine and pyroxene with relatively higher abundance of high silica phases this is a major previously unrecognized trend which appears to be pervasive in the mare serpentis region and possibly in other highland areas the detailed observations have led us to form two hypotheses for the relationship between these two units either 1 they are related through a widespread mechanical and or chemical alteration process where less mafic plains materials are derived from the mafic bedrock but have been compositionally altered in the process of regolith formation or 2 they are stratigraphically distinct units representing separate episodes of upper crust formation existing observations suggest that the second scenario is more likely in this scenario plains materials represent older degraded and possibly altered basement rock whereas the rocky exposures represent later additions to the crust and are probably volcanic in origin these hypotheses should be further testable with decimeter resolution imagery and meter resolution short wavelength infrared spectra

alpha particle x ray spectrometer apxs results from gusev crater and calibration report 1 the chemical composition of rocks and soils on mars analyzed during the mars exploration rover spirit mission was determined by x ray analyses with the alpha particle x ray spectrometer apxs details of the data analysis method and the instrument calibration are presented measurements performed on mars to address geometry effects and background contributions are shown cross calibration measurements among several instrument sensors and sources are discussed an unintentional swap of the two flight instruments is evaluated new concentration data acquired during the first 470 sols of rover spirit in gusev crater are presented there are two geological regions the gusev plains and the columbia hills the plains contain soils that are very similar to previous landing sites on mars a meteoritic component in the soil is identified rocks in the plains revealed thin weathering rinds the underlying abraded rock was classified as primitive basalt one of these rocks contained significant br that is probably associated with vein filling material of different composition one of the trenches showed large subsurface enrichments of mg s and br disturbed soils and rocks in the columbia hills revealed different elemental compositions these rocks are significantly weathered and enriched in mobile elements such as p s cl or br even abraded rock surfaces have high br concentrations thus in contrast to the rocks and soils in the gusev plains the columbia hills material shows more significant evidence of ancient aqueous alteration

correspondence and least squares analyses of soil and rock compositions for the viking lander 1 and pathfinder landing sites correspondence analysis is a dual q and r mode factor analysis that allows simultaneous visualization of relationships between normalized variables and samples the usefulness of the technique is first illustrated with an analysis of a simulated feldspar compositional data set and then applied to analysis of patterns among variables and samples for compositions obtained for viking lander 1 soils and pathfinder rocks and soils for the martian data the first two factors capture 90 of the variance data projected onto the plane defined by these two factors fall within a mixing triangle defined by three geologically plausible end members basaltic shergottite andesite and a halide kieserite evaporite however examination of data projected onto the second and third factors shows that the compositions are systematically displaced from the mixing triangle plane in the same general direction as the fe vector inclusion of a fe oxide e g hematite or maghemite as a reasonable fourth end member forms a mixing tetrahedron that encapsulates the data least squares mixing analysis of the data with these four end members and the elemental suite measured at both landing sites si al ti fe mg ca s cl implies that aeolian dust on rocks is a physical mixture of basalt and andesite derived materials in approximately equal proportions soil components at the two landing sites are similar to each other and less basalt like than the aeolian dust and viking 1 soils are more andesite rich than the pathfinder soils

mineralogy and chemistry of cobbles at meridiani planum mars investigated by the mars exploration rover opportunity numerous loose rocks with dimensions of a few centimeters to tens of centimeters and with no obvious physical relationship to outcrop rocks have been observed along the traverse of the mars exploration rover opportunity to date about a dozen of these rocks have been analyzed with opportunity s contact instruments providing information about elemental chemistry alpha particle x ray spectrometer iron mineralogy and oxidation states mossbauer spectrometer and texture microscopic imager these cobbles appear to be impact related and three distinct groups can be identified on the basis of chemistry and mineralogy the first group comprises bright fragments of the sulfate rich bedrock that are compositionally and texturally indistinguishable from outcrop rocks all other cobbles are dark and are divided into two groups referred to as the barberton group and the arkansas group after the first specimen of each that was encountered by opportunity barberton group cobbles are interpreted as meteorites with an overall chemistry and mineralogy consistent with a mesosiderite silicate clast composition arkansas group cobbles appear to be related to meridiani outcrop and contain an additional basaltic component they have brecciated textures pointing to an impact related origin during which local bedrock and basaltic material were mixed

overview of the spirit mars exploration rover mission to gusev crater landing site to backstay rock in the columbia hills spirit landed on the floor of gusev crater and conducted initial operations on soil covered rock strewn cratered plains underlain by olivine bearing basalts plains surface rocks are covered by wind blown dust and show evidence for surface enrichment of soluble species as vein and void filling materials and coatings the surface enrichment is the result of a minor amount of transport and deposition by aqueous processes layered granular deposits were discovered in the columbia hills with outcrops that tend to dip conformably with the topography the granular rocks are interpreted to be volcanic ash and or impact ejecta deposits that have been modified by aqueous fluids during and or after emplacement soils consist of basaltic deposits that are weakly cohesive relatively poorly sorted and covered by a veneer of wind blown dust the soils have been homogenized by wind transport over at least the several kilometer length scale traversed by the rover mobilization of soluble species has occurred within at least two soil deposits examined the presence of monolayers of coarse sand on wind blown bedforms together with even spacing of granule sized surface clasts suggests that some of the soil surfaces encountered by spirit have not been modified by wind for some time on the other hand dust deposits on the surface and rover deck have changed during the course of the mission detection of dust devils monitoring of the dust opacity and lower boundary layer and coordinated experiments with orbiters provided new insights into atmosphere surface dynamics

visible near infrared spectra and two layer modeling of palagonite coated basalts fine grained dust coatings on martian rocks and soils obscure underlying surfaces and hinder mineralogic interpretations of both remote sensing and in situ observations we investigate laboratory visible near infrared spectra of various thicknesses of palagonite coatings on basalt substrates we develop a two layer hapke scattering model incorporating porosity grain size and derived absorption coefficients of palagonite and basalt that reproduces the observed spectra only when the single scattering particle phase function is varied with wavelength

visible and near infrared multispectral analysis of geochemically measured rock fragments at the opportunity landing site in meridiani planum 1 we have used visible and near infrared panoramic camera pancam spectral data acquired by the opportunity rover to analyze 15 rock fragments at the meridiani planum landing site these spectral results were then compared to geochemistry measurements made by the in situ instruments mossbauer mb and alpha particle x ray spectrometer apxs to determine the feasibility of mineralogic characterization from pancam data our results suggest that dust and alteration rinds coat many rock fragments which limits our ability to adequately measure the mineralogy of some rocks from pancam spectra relative to the different field of view and penetration depths of mb and apxs viewing and lighting geometry along with sampling size also complicate the spectral characterization of the rocks rock fragments with the same geochemistry of sulfate rich outcrops have similar spectra although the sulfate rich composition cannot be ascertained based upon pancam spectra alone feni meteorites have spectral characteristics particularly ferric oxide coatings that generally differentiate them from other rocks at the landing site stony meteorites and impact fragments with unknown compositions have a diverse range of spectral properties and are not well constrained nor diagnostic in pancam data bounce rock with its unique basalt composition is easily differentiated in the pancam data from all other rock types at meridiani planum our pancam analyses of small pebbles adjacent to these 15 rock fragments suggests that other rock types may exist at the landing site but have not yet been geochemically measured

chemcam passive reflectance spectroscopy of surface materials at the curiosity landing site mars the spectrometers on the mars science laboratory msl chemcam instrument were used in passive mode to record visible near infrared 400 840 nm radiance from the martian surface using the onboard chemcam calibration targets housing as a reflectance standard we developed methods to collect calibrate and reduce radiance observations to relative reflectance such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover and represent the highest spatial resolution 0 65 mrad and spectral sampling 1 nm visible near infrared reflectance spectra from a landed platform on mars relative reflectance spectra of surface rocks and soils match those from orbital observations and multispectral data from the msl mastcam camera preliminary analyses of the band depths spectral slopes and reflectance ratios of the more than 2000 spectra taken during the first year of msl operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components initial comparisons of chemcam spectra to laboratory spectra of minerals and mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks magnesium rich raised ridges tend to exhibit distinct near infrared slopes the ferric absorption downturn typically found for martian materials at 600 nm is greatly subdued in brushed rocks and drill tailings consistent with their more ferrous nature calcium sulfate veins exhibit the highest relative reflectances observed but are still relatively red owing to the effects of residual dust such dust is overall less prominent on rocks sampled within the blast zone immediately surrounding the landing site these samples were likely affected by the landing thrusters which partially removed the ubiquitous dust coatings increased dust coatings on the calibration targets during the first year of the mission were documented by the chemcam passive measurements as well ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance spectra this will be useful as additional measurements are acquired during the rover s future examinations of hematite sulfate and phyllosilicate bearing materials near the base of mt sharp that are spectrally active in the 400 840 nm region

late quaternary sedimentation on the north aegean continental margin greece the late quaternary seismic stratigraphy of the north aegean continental shelf and adjacent basins has been interpreted from boomer and 3 5 khz seismic profiles ages derived from shallow cores and offshore wells and relative offsets on small synsedimentary faults provide chronological control sea level history inferred from seismic stratigraphy correlates with the global eustatic sea level record based on oxygen isotopic curves outer shelf progradation correlates with lowstands of sea level in isotopic stages 2 3 and 6 whereas shelf wide transgression surfaces correspond to the stage 6 5 and 2 1 transitions when rapid deglaciation occurred the present depth of the delta plain formed on the outer shelf during the late stage 6 lowstand provides a dated and originally horizontal marker for estimating rates of tectonic subsidence gross distribution of sediment facies is similar in both tectonically stable and active areas the shelf break formed by delta progradation but is marked by faults in most places because of the accommodation provided by graben subsidence rates of 0 3 1 5 mm yr standard sequence stratigraphic analysis can be applied to these sediments deposited during high amplitude quaternary sea level oscillations high rates of subsidence result in the preservation of an unusually complete record of sea level change major lowstand progradation is dependent on the duration rather than the magnitude of sea level lowstand the long glaciations in isotopic stages 6 12 16 and 22 resulted in the most prominent seaward progradation on the margin sandy lowstand turbidite deposits formed only when there was rapid fall in sea level otherwise sand was trapped on delta tops and silty muds were deposited in deep water

mars exploration rover geologic traverse by the spirit rover in the plains of gusev crater mars the spirit rover completed a 2 5 km traverse across gently sloping plains on the floor of gusev crater from its location on the outer rim of bonneville crater to the lower slopes of the columbia hills mars using the athena suite of instruments in a transect approach a systematic series of overlapping panoramic mosaics remote sensing observations surface analyses and trenching operations documented the lateral variations in landforms geologic materials and chemistry of the surface throughout the traverse demonstrating the ability to apply the techniques of field geology by remote rover operations textures and shapes of rocks within the plains are consistent with derivation from impact excavation and mixing of the upper few meters of basaltic lavas the contact between surrounding plains and crater ejecta is generally abrupt and marked by increases in clast abundance and decimeter scale steps in relief basaltic materials of the plains overlie less indurated and more altered rock types at a time stratigraphic contact between the plains and columbia hills that occurs over a distance of one to two meters this implies that regional geologic contacts are well preserved and that earth like field geologic mapping will be possible on mars despite eons of overturn by small impacts

salt diapir influenced shallow marine sediment dispersal patterns insights from outcrop analogs unique outcrop exposures of two salt diapirs a secondary salt weld and associated syndiapiric strata in northeast mexico offer an important perspective on salt influenced petroleum reservoirs by allowing recognition and description of salt related sandstone depocenters spectacular progressive unconformities and halokinetic sequences coupled with laterally continuous exposures permit accurate correlation and interpretation of syndiapiric units analysis of the syndiapiric upper cretaceous delgado sandstone member potrerillos formation delineates regional shoreline sediment dispersal locally impacted by diapiric relief and the distribution and internal character of salt diapir proximal sandstone depocenters sequence stratigraphic correlation defines striking relationships between highstand hst and transgressive systems tracts tst stratal thinning trends and salt diapir relief transgressive systems tract and highstand systems tract strata show thinning and lithofacies shoaling trends toward diapirs however the latter is more pronounced in the hst and occurs at a greater distance from salt diapirs within 1 2 km 0 6 1 2 mi sandstone depocenters roughly 0 5 1 0 km 0 3 0 6 mi wide and 0 5 0 2 km 0 3 0 1 mi thick are present in both tst and hst strata and consist of sandier shallower water facies however depocenters are better developed in tst strata as thicker stratigraphic sections on updip diapir margins we propose that sandstone depocenters formed by preferential sediment reworking and shelf ridge development on landward diapir margins during marine transgression elevated diapir relief and higher subsidence rates adjacent to salt diapirs likely enhanced this process additionally depocenters adjacent to el papalote diapir are smaller and contain deeper water facies than the age equivalent depocenters adjacent to el gordo diapir suggesting that it had higher broader sea floor relief

effect of cenozoic ice sheet fluctuations in antarctica on the stratigraphic signature of the neogene stratigraphic successions from the gulf of mexico offshore alabama northeast java indonesia ross sea antarctica and several other continental margins have been examined all are characterized by very similar neogene stratal geometries in seismic profiles and well log cross sections from these areas a large mid oligocene i e latest early oligocene earliest late oligocene basinward shift in coastal onlap is followed by a major early miocene transgression and aggradation which is in turn followed by early middle miocene transgressions and late middle and late miocene progradational episodes the succession culminates in plio pleistocene high frequency progradations and transgressions the interregional character of the neogene stratal signature and its similarity to the stratal geometry found in seismic data from the ross sea continental shelf antarctica suggest that the neogene stratal signature is a manifestation of glacioeustatic fluctuations a review of the literature and an analysis of recently acquired and published data indicate that the first major ice sheet grounding event in the ross sea occurred during middle to late oligoce time the ross sea is the repository for ice flowing from a major portion of the continental interior thus the glacial record of the ross sea should serve as a gage of ice volume changes on the continent that were large enough to influence global eustasy the ice advance onto the ross sea continental shelf during middle to late oligocene time may have been the result of a decrease in the rate of shelf subsidence as rifting in the ross sea slowed or ceased advance of the ice sheet resulted in widespread erosion of the continental shelf and shelf overdeepening it is hypothesized that metastable marine based ice sheets have waxed and waned on the antarctic continental shelf since at least the oligocene and that the these waxing and waning events were responsible for the development of a global neogene stratigraphic signature

glaciovolcanic hydrothermal environments in iceland and implications for their detection on mars abstract volcanism has been a dominant process on mars along with a pervasive global cryosphere therefore the interaction between these two is considered likely terrestrial glaciovolcanism produces distinctive lithologies and alteration terrains as well as hydrothermal environments that can be inhabited by microorganisms here we provide a framework for identifying evidence of such glaciovolcanic environments during future mars exploration and provide a descriptive reference for active hydrothermal environments to be utilised for future astrobiological studies remote sensing data were combined with field observations and sample analysis that included x ray diffraction raman spectroscopy thin section petrography scanning electron microscopy electron dispersive spectrometer analysis and dissolved water chemistry to characterise samples from two areas of basaltic glaciovolcanism askja and kverkfjoll volcanoes in iceland the glaciovolcanic terrain between these volcanoes is characterised by subglacially erupted fissure swarm ridges which have since been modified by multiple glacial outburst floods active hydrothermal environments at kverkfjoll include hot springs anoxic pools glacial meltwater lakes and sulphur and iron depositing fumaroles all situated within ice bound geothermal fields temperatures range from 0 c 94 4 c and aqueous environments are acidic neutral ph 2 7 5 and sulphate dominated mineralogy of sediments mineral crusts and secondary deposits within basalts suggest two types of hydrothermal alteration a low temperature 120 c assemblage signified by zeolite heulandite and quartz these mineral assemblages are consistent with those identified at the martian surface in situ and laboratory vnir 440 1000 nm reflectance spectra representative of mars rover multispectral imaging show sediment spectral profiles to be influenced by fe2 3 bearing minerals regardless of their dominant bulk mineralogy characterising these terrestrial glaciovolcanic deposits can help identify similar processes on mars as well as identifying palaeoenvironments that may once have supported and preserved life

alkaline volcanic rocks from the columbia hills gusev crater mars 1 irvine backstay and wishstone are the type specimens for three classes of fine grained or fragmental relatively unaltered rocks with distinctive thermal emission spectra found as float on the flanks of the columbia hills chemical analyses indicate that these rocks are mildly alkaline basalt trachybasalt and tephrite respectively their mineralogy consists of na and k rich feldspar s low and high ca pyroxenes ferroan olivine fe ti and possibly cr oxides phosphate and possibly glass the texture of wishstone is consistent with a pyroclastic origin whereas irvine and backstay are lavas or possibly dike rocks chemical compositions of these rocks plot on or near liquid lines of descent for most elements calculated for adirondack class rocks olivine rich basalts from the gusev plains at various pressures from 0 1 to 1 0 gpa we infer that wishstone backstay and irvine class magmas may have formed by fractionation of primitive oxidized basaltic magma similar to adirondack class rocks the compositions of all these rocks reveal that the gusev magmatic province is alkaline distinct from the subalkaline volcanic rocks thought to dominate most of the planet s surface the fact that differentiated volcanic rocks were not encountered on the plains prior to ascending husband hill may suggest a local magma source for volcanism beneath gusev crater

in flight calibration and performance of the mars exploration rover panoramic camera pancam instruments 1 the mars exploration rover panoramic camera mer pancam instruments have acquired more than 60 000 high resolution multispectral stereoscopic images of soil rocks and sky at the gusev crater and meridiani planum landing sites since january 2004 these images combined with other mer data sets have enabled new discoveries about the composition mineralogy and geologic geochemical evolution of both sites one key to the success of pancam in contributing to the overall success of mer has been the development of a calibration pipeline that can quickly remove instrumental artifacts and generate both absolute radiance and relative reflectance images with high accuracy and precision in order to influence tactical rover driving and in situ sampling decisions this paper describes in detail the methods assumptions and models algorithms in the calibration pipeline developed for pancam images based on new measurements and refinements performed primarily from flight data acquired on mars major calibration steps include modeling and removal of detector bias signal active and readout region dark current electronic shutter smear and pixel to pixel responsivity flatfield variations pancam images are calibrated to radiance w m2 nm sr using refined preflight derived calibration coefficients or radiance factor i f using near in time measurements of the pancam calibration target and a model of aeolian dust deposition on the target as a function of time we are able to verify that the absolute radiance calibration of most pancam images is accurate to within about 10 or less and that the filter to filter and pixel to pixel precision of the calibrated relative reflectance data both based on measurements of the pancam calibration target are typically about 3 and 1 or less respectively examples are also presented of scientific applications made possible by the high fidelity of the calibrated pancam data these include 11 color visible to near ir spectral analysis calculation of true color and chromaticity values and generation of super resolution image data products this work represents a follow on and enhancement to the pancam preflight calibration process described by bell et al 2003

major and trace element compositions of surface sediments from the lower bengal fan implications for provenance discrimination and sedimentary environment abstract the bengal fan the largest submarine fan in the world receives a large amount of terrestrial material from the himalayas and the indian peninsula making it an ideal area for studying land sea interactions in different time scales using the major and trace element compositions of 98 surface sediment samples from the lower bengal fan we identified the provenances of the sediments calculated the relative contributions of each provenance and further assessed their controlling factors the statistic results of the major and trace elements confirm that terrigenous materials comprise the majority on the sediment and that the study area can be divided into three depositional provinces the main sources of sediments are the himalayas and indian river systems which can be distinguished in the fe al k al scatter diagram based on calculation results of a two end member mixing model the relative contributions of the himalayas and the indian rivers are 55 and 45 respectively however the spatial distributions of sediments from these two sources in the three provinces exhibit a large variation the himalayan contributions decrease from 63 in province i southeast part of the study area to 53 in province ii central part of the study area and 45 in province iii northwest part of the study area correspondingly the contributions of indian rivers increase from province i through province iii during the high sea levels of modern time seasonal monsoonal currents play a key role in controlling the sediments transport from south asia continent to the lower fan

late quaternary depositional systems and sea level change santa monica and san pedro basins california continental borderland a suite of seismic reflection data that provides different degrees of resolution and penetration was used to map the depositional systems that have developed in santa monica and san pedro basins during the late quaternary submarine fan growth particularly at the mouths of hueneme and redondo canyons has been the dominant mode of basin filling mass movement processes ranging from creep to large scale catastrophic slumping have been important locally in general large scale fan growth fits normark s model in which the suprafan is the primary locus of coarse sediment deposition smaller scale morphologic and depositional patterns on the hueneme and redondo fans e g distributary channels and coarse sediment concentrations basinward of the inner suprafan suggest that a significant amount of coarse sediment presently bypasses the suprafans however long distance coarse sediment transport was particularly pronounced during late wisconsinan lowstand of sea level and resulted in progradation of lower mid fan and lower fan deposits as sea level rose rapidly between 18 000 y b p and 10 000 y b p shelves trapped much of the sediment supply consequently rates of basin sedimentation decreased markedly and the area of fan developmen was restricted as the rate of shelf sedimentation decreased concomitantly with a decrease in the rate of sea level rise 10 000 y b p sediment transport to the basins was renewed and modern depositional patterns were established fan development also has been influenced by large scale mass movement extensive mid fan overbank flow and the consequent development of sediment waves deflection of turbidity currents by bathymetric obstacles and local tectonism correlations between sand layer characteristics and high resolution echo types for fan and basin plain deposits show trends similar to some of those observed in deep sea depositional environments however because santa monica and san pedro basins are small enclosed tectonically active basins that receive sediment from relatively large drainage areas proximal to distal changes in sand layer thickness abundance and frequency are less pronounced than those observed in deep sea environments

oceanic pollen transport and pollen dinocyst ratios as markers of late cenozoic sea level change and sediment transport abstract palynological studies of late cenozoic cores from nine sites show large peaks in the ratio of pollen and spores to dinocysts p d which reflect major increases in terrigenous sediment influx to the north atlantic ocean under normal pelagic conditions in the north atlantic i e in the absence of ice rafting or mass wasting p d in oceanic sediments is low usually

athena mars rover science investigation 1 each mars exploration rover carries an integrated suite of scientific instruments and tools called the athena science payload the primary objective of the athena science investigation is to explore two sites on the martian surface where water may once have been present and to assess past environmental conditions at those sites and their suitability for life the remote sensing portion of the payload uses a mast called the pancam mast assembly pma that provides pointing for two instruments the panoramic camera pancam and the miniature thermal emission spectrometer mini tes pancam provides high resolution color stereo imaging while mini tes provides spectral cubes at mid infrared wavelengths for in situ study a five degree of freedom arm called the instrument deployment device idd carries four more tools a microscopic imager mi for close up imaging an alpha particle x ray spectrometer apxs for elemental chemistry a mossbauer spectrometer mb for the mineralogy of fe bearing materials and a rock abrasion tool rat for removing dusty and weathered surfaces and exposing fresh rock underneath the payload also includes magnets that allow the instruments to study the composition of magnetic martian materials all of the athena instruments have undergone extensive calibration both individually and using a set of geologic reference materials that are being measured with all the instruments using a mer like rover and payload in a number of field settings we have devised operations processes that will enable us to use the mer rovers to formulate and test scientific hypotheses concerning past environmental conditions and habitability at the landing sites

maastrichtian climate productivity and faunal turnovers in planktic foraminifera in south atlantic dsdp sites 525a and 21 abstract stratigraphic faunal and isotopic analyses of the maastrichtian at dsdp sites 525a and 21 in the south atlantic reveal a planktic foraminiferal fauna characterized by two major events an early late maastrichtian diversification and end maastrichtian mass extinction both events are accompanied by major changes in climate and productivity the diversification event which occurred in two steps between 70 5 and 69 1 ma increased species richness by a total of 43 and coincided with the onset of major cooling in surface and bottom waters and increased surface productivity the onset of the terminal decline in maastrichtian species richness began at 67 5 ma and the first significant decline in surface productivity occurred at 66 2 ma coincident maximum cooling to 13 c in surface waters and the reduction of the surface to deep temperature gradient to less than 5 c major climatic and moderate productivity changes mark the mass extinction and the last 500 kyr of the maastrichtian between 200 and 400 kyr before the k t boundary surface and deep waters warmed rapidly by 3 4 c and cooled again during the last 100 kyr of the maastrichtian surface productivity decreased only moderately across the k t boundary species richness began to decline during the late maastrichtian cooling and by k t boundary time the mass extinction had claimed 66 of the species viewed within the context of maastrichtian climate and productivity changes the k t mass extinction could have resulted from extreme environmental stress even without the addition of an extraterrestrial impact

constraints on iron sulfate and iron oxide mineralogy from chemcam visible near infrared reflectance spectroscopy of mt sharp basal units gale crater mars relative reflectace point spectra 400 840 nm were acquired by the chemistry and camera chemcam instrument on the mars science laboratory msl rover curiosity in passive mode no laser of drill tailings and broken rock fragments near the rover as it entered the lower reaches of mt sharp and of landforms at distances of 2 8 km freshly disturbed surfaces are less subject to the spectral masking effects of dust and revealed spectral features consistent with the presence of iron oxides and ferric sulfates we present the first detection on mars of a 433 nm absorption band consistent with small abundances of ferric sulfates corroborated by jarosite detections by the chemistry and mineralogy chemin x ray diffraction instrument in the mojave telegraph peak and confidence hills drilled samples disturbed materials near the bonanza king region also exhibited strong 433 nm bands and negative near infrared spectral slopes consistent with jarosite chemcam passive spectra of the confidence hills and mojave drill tailings showed features suggestive of the crystalline hematite identified by chemin analyses the windjana drill sample tailings exhibited flat low relative reflectance spectra explained by the occurrence of magnetite detected by chemin passive spectra of bonanza king were similar suggesting the presence of spectrally dark and neutral minerals such as magnetite long distance spectra of the hematite ridge feature 3 5 km from the rover exhibited features consistent with crystalline hematite the bagnold dune field north of the hematite ridge area exhibited low relative reflectance and near infrared features indicative of basaltic materials olivine pyroxene light toned layers south of hematite ridge lacked distinct spectral features in the 400 840 nm region and may represent portions of nearby clay minerals and sulfates mapped with orbital near infrared observations the presence of ferric sulfates such as jarosite in the drill tailings suggests a relatively acidic environment likely associated with flow of iron bearing fluids associated oxidation and or hydrothermal leaching of sedimentary rocks combined with other remote sensing data sets mineralogical constraints from chemcam passive spectra will continue to play an important role in interpreting the mineralogy and composition of materials encountered as curiosity traverses further south within the basal layers of the mt sharp complex

visible to near infrared msl mastcam multispectral imaging initial results from select high interest science targets within gale crater mars the mastcam ccd cameras on the mars science laboratory curiosity rover each use an 8 position filter wheel in acquiring up to 1600 1200 pixel images the filter set includes a broadband near infrared cutoff filter for rgb bayer imaging on each camera and 12 narrow band geology filters distributed between the two cameras spanning the wavelength range 445 1013 nm this wavelength region includes the relatively broad charge transfer and crystal field absorption bands that are most commonly due to the presence of iron bearing minerals to identify such spectral features sequences of images taken with identical pointings through different filters have been calibrated to relative reflectance using pre flight calibration coefficients and in flight measurements of an onboard calibration target within the first 1000 sols of the mission mastcam observed a spectrally diverse set of materials displaying absorption features consistent with the presence of iron bearing silicate iron oxide and iron sulfate minerals dust coated surfaces as well as soils possess a strong positive reflectance slope in the visible consistent with the presence of nanophase iron oxides which have long been considered the dominant visible wavelength pigmenting agent in weathered martian surface materials fresh surfaces such as tailings produced by the drill tool and the interiors of rocks broken by the rover wheels are grayer in visible wavelengths than their reddish dust coated surfaces but possess reflectance spectra that vary considerably between sites to understand the mineralogical basis of observed mastcam reflectance spectra we focus on a subset of the multispectral data set for which additional constraints on the composition of surface materials are available from other rover instruments with an emphasis on sample sites for which detailed mineralogy is provided by the results of chemin x ray diffraction analyses we also discuss the results of coordinated observations with the chemcam instrument whose passive mode of operation is capable of acquiring reflectance spectra over wavelengths that considerably overlap the range spanned by the mastcam filter set johnson et al 2016 materials that show a distinct 430 nm band in chemcam data also are observed to have a strong near infrared absorption band in mastcam spectral data consistent with the presence of a ferric sulfate mineral long distance mastcam observations targeted toward the flanks of the gale crater central mound are in agreement with both chemcam spectra and orbital results and in particular exhibit the spectral features of a crystalline hematite layer identified in mro crism data variations observed in mastcam multi filter images acquired to date have shown that multispectral observations can discriminate between compositionally different materials within gale crater and are in qualitative agreement with mineralogies from measured samples and orbital data

observations of rock spectral classes by the opportunity rover s pancam on northern cape york and on matijevic hill endeavour crater mars the opportunity rover s exploration of the portion of the rim of endeavour crater known as cape york included examination of the sulfate bearing grasberg formation and the matijevic hill region multispectral visible and near infrared vnir pancam observations were used to characterize reflectance properties of rock units using spectral end member detection and classification approaches including a principal components n dimensional visualization automatic sequential maximum angle convex cone method and classification through hierarchical clustering six main spectral classes of rock surfaces were identified light toned veins grasberg fm the smectite bearing matijevic formation the hematitic blueberry spherules resistant spherules within the matijevic fm dubbed newberries and the shoemaker formation impact breccia some of these could be divided into spectral subclasses there were three types of veins veins in the bench unit of cape york thinner veins in the matijevic fm and boxwork pattern forming veins the bench unit veins had higher 535 nm band depths than the other two vein subclasses and a steeper 934 to 1009 nm slope the grasberg fm has vnir spectral features that are interpreted to indicate higher fractions of red hematite than in the sulfate bearing burns fm the matijevic fm includes both light toned fine grained matrix and dark toned veneers the latter has a weak near infrared absorption band centered near 950 nm consistent with nontronite observations of rock abrasion tool brushed and ground newberries indicated that cuttings from the rat grind had a longer wavelength reflectance maximum and deeper 535 nm band depth consistent with more oxidized materials greater oxidation of cementing materials in the newberries is consistent with a diagenetic concretion origin

correlating multispectral imaging and compositional data from the mars exploration rovers and implications for mars science laboratory abstract in an effort to infer compositional information about distant targets based on multispectral imaging data we investigated methods of relating mars exploration rover mer pancam multispectral remote sensing observations to in situ alpha particle x ray spectrometer apxs derived elemental abundances and mossbauer mb derived abundances of fe bearing phases at the mer field sites in gusev crater and meridiani planum the majority of the partial correlation coefficients between these data sets were not statistically significant restricting the targets to those that were abraded by the rock abrasion tool rat led to improved pearson s correlations most notably between the red blue ratio 673 nm 434 nm and fe3 bearing phases but partial correlations were not statistically significant partial least squares pls calculations relating pancam 11 color visible to near ir vnir 400 1000 nm spectra to apxs and mossbauer element or mineral abundances showed generally poor performance although the presence of compositional outliers led to improved pls results for data from meridiani when the meridiani pls model for pyroxene was tested by predicting the pyroxene content of gusev targets the results were poor indicating that the pls models for meridiani are not applicable to data from other sites soft independent modeling of class analogy simca classification of gusev crater data showed mixed results of the 24 gusev test regions of interest rois with known classes 11 had 30 of the pixels in the roi classified correctly while others were mis classified or unclassified k means clustering of apxs and mossbauer data was used to assign meridiani targets to compositional classes the clustering derived classes corresponded to meaningful geologic and or color unit differences and simca classification using these classes was somewhat successful with 30 of pixels correctly classified in 9 of the 11 rois with known classes this work shows that the relationship between swir multispectral imaging data and apxs and mossbauer derived composition mineralogy is often weak a perhaps not entirely unexpected result given the different surface sampling depths of swir imaging uppermost few microns vs apxs tens of m and mb measurements hundreds of m results from the upcoming mars science laboratory msl rover s chemcam laser induced breakdown spectroscopy libs instrument may show a closer relationship to mastcam swir multispectral observations however because the initial laser shots onto a target will analyze only the upper few micrometers of the surface the clustering and classification methods used in this study can be applied to any data set to formalize the definition of classes and identify targets that do not fit in previously defined classes

theropod avian pterosaur and arthropod tracks from the uppermost cretaceous las encinas formation coahuila northeastern mexico and their significance for the end cretaceous mass extinction two unique localities that combine an unusual diversity of avian pterosaurian and dinosaur tracks as well as trails of arthropods were recently discovered by us in uppermost maastrichtian siliciclastic sediments of the las encinas formation in the mexican state of coahuila 40 km north of saltillo the trackway assemblages at amargos and rancho san francisco were produced by at least six different types of birds while trackways of azhdarchoid pterosaurs are rare only a single footprint was produced by a nonavian theropod a diverse ichnofauna of arthropod traces is also present in a different facies the tetrapod trackway assemblage was deposited during the very latest maastrichtian as indicated by an up to 2 5 m thick unit with abundant smectite spherules attributed to the chicxulub impact less than 8 5 m stratigraphically up section at amargos sphenodiscus pleurisepta is the last ammonite at amargos and may have crossed the cretaceous paleogene boundary

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

basinward transport of chicxulub ejecta by tsunami induced backflow la popa basin northeastern mexico and its implications for distribution of impact related deposits flanking the gulf of mexico ejecta bearing strata are present at the top of cretaceous foreland basin deposits throughout the la popa basin in northeastern mexico in the southeast part of the basin locally thick as much as 4 6 m ejecta rich conglomeratic strata occupy valley like features at a bathymetric break that separated maastrichtian upper shoreface from lower shoreface and prodelta depositional settings clast supported textures normally graded planar conglomerate sandstone couplets upcurrent dipping low angle cross laminae sparse paleocurrent data and transported fossils indicate deposition by south to southeast directed turbulent supercritical flow in the northwest part of the basin ejecta grains are present but less common in correlative deposits sediment ejecta and organisms were eroded from shoreward environments and transported basinward by backflow of run up surge s emplaced against the continent by one or several tsunami s high discharge supercritical offshore directed flow provides a mechanism for transport of voluminous ejecta bearing sediment and late maastrichtian marine organisms into deep water gulf of mexico settings

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

evidence for montmorillonite or its compositional equivalent in columbia hills mars 1 during its exploration of the columbia hills the mars exploration rover spirit encountered several similar samples that are distinctly different from martian meteorites and known gusev crater soils rocks and sediments occurring in a variety of contexts and locations these independence class samples are rough textured iron poor equivalent feo 4 wt have high al si ratios and often contain unexpectedly high concentrations of one or more minor or trace elements including cr ni cu sr and y apart from accessory minerals the major component common to these samples has a compositional profile of major and minor elements which is similar to the smectite montmorillonite implicating this mineral or its compositional equivalent infrared thermal emission spectra do not indicate the presence of crystalline smectite one of these samples was found spatially associated with a ferric sulfate enriched soil horizon possibly indicating a genetic relationship between these disparate types of materials compared to the nearby wishstone and watchtower class rocks major aqueous alteration involving mineral dissolution and mobilization with consequent depletions of certain elements is implied for this setting and may be undetectable by remote sensing from orbit because of the small scale of the occurrences and obscuration by mantling with soil and dust

mineral sands occurrences in the murray basin southeastern australia the murray basin in southeastern australia is proving to be a major mineral sand province that eventually will replace australia s east and west coasts in production of rutile zircon and ilmenite concentrations of relatively coarse grained heavy mineral occur as beach placers in the pliocene loxton parilla sands in the upper part of the murray basin sequence these formed as 400 km long barrier complexes in the murravian gulf under the action of long period ocean swell waves we think the main source of barrier sand at least initially was from erosion of miocene sands on the bed of the murravian gulf progradation was a response to sea level fluctuations linked to milankovitch climatic cycles in the pliocene in most areas the resulting 400 km wide barrier strand plain is now overlain by fluvial aeolian and lacustrine deposits typically the heavy mineral deposits are ilmenite rich with 30 to 40 percent rutile and zircon they occur as single or as multiple stacked strandline deposits are often more than 10 m thick have mineral grades that exceed 20 percent in places are several hundred meters wide and 10 to 25 km long some contain up to several million tonnes of heavy mineral the rutile and zircon are comparable in grain size and quality to minerals traditionally mined in australia many of the deposits are associated with topographic ridges the neckarboo and iona ridges are the best known that appear to be fault bounded blocks deposits of major commercial significance found so far contain a total of over 12 million tonnes mt of rutile zircon and ilmenite the total coarse grained mineral sand resources in the murray basin are conservatively estimated to be over 50 mt the distribution of mineral sands in the murray basin seems to be associated with two aspects of the region s geology and geomorphology 1 a zone bordering the central part of the basin where the pliocene barriers were derived from underlying miocene sands that probably already contained some mineral concentrations and 2 growth faulting with deposits preferentially occurring on upfaulted blocks especially in the zone defined by 1 above we speculate that localized uplift during the formation of the loxton parilla barriers was sufficient to modify coastal processes on uplifted blocks so as to increase the rate of alongshore sediment bypass compared to nearby areas this phenomenon has been simulated in computer modeling where the barrier sands were already enriched in heavy minerals winnowing by storm waves formed beach placers on the uplifted fault blocks based on criteria 1 and 2 the prospective areas of the murray basin account for 80 percent of the beach placers found to date

context of ancient aqueous environments on mars from in situ geologic mapping at endeavour crater using the mars exploration rover opportunity we have compiled one of the first field geologic maps on mars while traversing the noachian terrain along the rim of the 22 km diameter endeavour crater latitude 2 16 33 longitude 5 10 51 in situ mapping of the petrographic elemental structural and stratigraphic characteristics of outcrops and rocks distinguishes four mappable bedrock lithologic units three of these rock units predate the surrounding burns formation sulfate rich sandstones and one the matijevic formation represents conditions on early mars predating the formation of endeavour crater the stratigraphy assembled from these observations includes several geologic unconformities the differences in lithologic units across these unconformities record changes in the character and intensity of the martian aqueous environment over geologic time water circulated through fractures in the oldest rocks over periods long enough that texturally and elementally significant alteration occurred in fracture walls these oldest pre endeavour rocks and their network of mineralized and altered fractures were preserved by burial beneath impact ejecta and were subsequently exhumed and exposed the alteration along joints in the oldest rocks and the mineralized veins and concentrations of trace metals in overlying lithologic units is direct evidence that copious volumes of mineralized and or hydrothermal fluids circulated through the early martian crust the wide range in intensity of structural and chemical modification from outcrop to outcrop along the crater rim shows that the ejecta of large 8 km in diameter impact craters is complex these results imply that geologic complexity is to be anticipated in other areas of mars where cratering has been a fundamental process in the local and regional geology and mineralogy

vnir multispectral observations of rocks at cape york endeavour crater mars by the opportunity rover s pancam from its arrival at the portion of the rim of endeavour crater known informally as cape york the mars exploration rover opportunity has made numerous visible and near infrared vnir multispectral observations of rock surfaces this paper describes multispectral observations from opportunity s arrival at cape york to its winter over location at greeley haven averages of pixels from the pancam s left and right eyes were joined to form 11 point spectra from numerous observations and were examined via a number of techniques these included principal components analysis a sequential maximum angle convex cone approach examination of spectral parameters and a hierarchical clustering approach the end result of these analyses was the determination of six primary spectral ps classes describing spectrally unique materials observed on cape york these classes consisted of a standard outcrop spectrum that was observed on the clasts and matrix comprising the upper unit of the shoemaker formation a class representing rock surfaces exposed around odyssey crater and typified by the rocks of the tisdale series pebbles occurring in and weathered out of the upper unit of the shoemaker formation that appear red in 1009 904 754 nm color composites patches on tisdale rocks exhibiting a 864 nm band minimum that were spectrally anomalous in root mean square error images derived from spectral mixture analyses clasts with a high 904 nm band depth occurring in the greeley haven location and gypsum veins typified by the vein homestake comparisons of three of these classes that had well defined band minima between 800 and 1009 nm with spectral library spectra of ferrous silicates and ferric oxide oxyhydroxide and ferric sulfate minerals indicated tentative matches of the red pebbles with orthopyroxenes of the spectrally anomalous 864 nm band minimum material with hematite or ferric sulfates and of the high 904 nm band depth material with an orthopyroxene clinopyroxene mixture the spectral properties of rock surfaces on cape york are distinct from those of burns formation outcrops observed on the meridiani plains the cape york outcrop is noachian in age and study of these materials provides insight into less acidic environmental conditions extant before the formation of the burns formation

esperance multiple episodes of aqueous alteration involving fracture fills and coatings at matijevic hill mars in the search for evidence of past aqueous activity by the mars exploration rover opportunity fracture filling veins and rock coatings are prime candidates for exploration at one location within a segment of remaining rim material surrounding endeavour crater a set of boxwork fractures in an outcrop called esperance are filled by a bright hydrated and highly siliceous sio2 66 wt material which has overall a montmorillonite like chemical composition this material is partially covered by patches of a thin dark coating that is sulfate rich so3 21 wt but also contains significant levels of si fe ca and mg the simultaneous presence of abundant s si and fe indicates significant mineralogical complexity within the coating this combination of vein and coating compositions is unlike previous analyses on mars both materials are heterogeneously eroded presumably by eolian abrasion the evidence indicates at least two separate episodes of solute precipitation from aqueous fluids at this location possibly widely separated in time in addition to the implications for multiple episodes of alteration at the surface of the planet aqueous chemical environments such as these would have been habitable at the time of their formation and are also favorable for preservation of organic material

contemporary sedimentary processes in the monterey canyon fan system abstract a study of the monterey canyon and fan was conducted to investigate contemporary sedimentary activity using a camera sled alvin dives and sea beam bathymetry physical characteristics and plan view morphology of the walls terraces thalweg floor and levees of the monterey canyon and fan as well as the gullied and non gullied regions of the adjacent continental slope have been studied the canyon floor and fan valley thalweg channel from 2900 to 3500 m exhibited properties indicative of moderate to low energy conditions weak currents smoothed sea bed deposits of disintegrated kelp bioturbated mud substrate fecal pellets absence of scour chemosynthetic communities consisting of clams and a pogonophoran were found in the fan valley from 3000 to 3600 m local areas of rockfalls and slumps from the canyon and fan valley walls were not fresh sedimented abundantly colonized by benthic biota terraces and levee crests were mud draped and bedrock exposures on canyon walls were encrusted by benthic organisms freshest disturbances were found in gullies on the adjacent continental slope where bedrock was scoured clean of sediment and loose debris a major submarine slide detached from escarpments on the lower slope and extends across the fan the slide surface was mud draped hummocky and contained bedforms with wavelengths up to 150 m and up to 10 m relief the survey was conducted shortly before the loma prieta earthquake october 17 1989 that caused substantial ground motion in on shore regions of monterey bay any substantial sub sea disturbances generated by the ensuing earthquake should be discernable from the pre earthquake state by comparison with the deep sea photographs and observations

allochthonous salt structure and stratigraphy of the north eastern gulf of mexico part ii structure abstract the kinematic evolution of allochthonous salt in the north eastern gulf of mexico proceeds in three stages 1 since its middle jurassic deposition the louann salt was loaded by sediments causing episodic basinward movement of salt ultimately leading to large concentrations of salt masses in a slope environment by the end of the lower cretaceous 2 a regime of starved sedimentation during late cretaceous and early oligocene is responsible for the stabilization of these early salt accumulations 3 with renewed rapid accumulation of sediments during the neogene and pliocene extensive allochthonous salt tongues and sheets formed by gravity spreading within the younger sediments of the slope autochthonous salt allochthonous salt and detached allochthonous salt are typical stages of evolution major down to the basin growth faults separate allochthonous salt sheets from their original feeder stocks extension along down to the basin master growth faults is compensated mainly by salt withdrawal and partly by basinward shortening

sequence stratigraphy of mississippi fan related to oxygen isotope sea level index 1 the techniques of sequence stratigraphy were applied to the analysis of stratal patterns on seismic data from the mississippi fan to outline a method for 1 understanding the processes and growth patterns of modern submarine fans and 2 predicting reservoir and seal for exploration in deep water settings we developed a sea level index from the oxygen isotope record for the last 3 5 m y tied to limited biostratigraphic control to provide a time framework within which the depositional patterns were analyzed analysis of the seismic data reveals that at least thirteen depositional sequences comprise the bulk of the mississippi fan section the base of each sequence is defined by an erosional unconformity in a proximal position that can be traced regionally across the fan complex with its correlative conformity seismic facies analysis of individual sequences suggests that the mississippi fan is characterized by the cyclic stacking of individual lowstand systems tract deposits consisting dominantly of the lowstand basin floor and lowstand slope fans lowstand slope fans consisting of leveed channel complexes are volumetrically the greatest component of the mississippi fan lowstand basin floor fans commonly are sandy and thin and are associated with the base of each depositional sequence these fans are characterized by a mounded stratal geometry

vnir multispectral observations of aqueous alteration materials by the pancams on the spirit and opportunity mars exploration rovers multispectral visible and near infrared vnir observations from the mars exploration rover pancam multispectral stereo camera systems are consistent with materials having been subjected to various aqueous processes ferric oxides in the form of hematite in the burns and grasberg formations of meridiani planum have been well characterized by opportunity on the basis of strong 535 and 864 nm absorptions and positive 754 1009 nm and 934 1009 nm slopes on the rim of noachian aged endeavour crater opportunity has observed light toned veins with high ca and s as determined by the rover s alpha particle x ray spectrometer apxs and a negative 934 1009 nm slope in vnir spectra extracted from pancam data indicative of a 1000 nm h2o overtone absorption together these observations indicate that the veins are composed of gypsum rocks overturned by opportunity on the murray ridge portion of the endeavour crater rim display dark and light toned coatings the dark toned coatings have a red featureless slope that is consistent with the slope observed in laboratory spectra of high valence manganese oxide minerals potential mn oxide coatings may also be associated with some exposures of the grasberg formation apxs results for high mg and s in the light toned coatings of the murray ridge overturned rocks and a negative 934 1009 nm slope are consistent with hydrated mg sulfates opportunity has also observed spectral features in rocks that are consistent with orbital observations of fe smectites as well as al smectites and possible hydrated silica in light toned fracture fill materials the spirit rover observed sulfate rich light toned soils exposed by the rover s wheels several of these soil observations contained spectral features such as a broad absorption centered near 800 nm consistent with ferric sulfate minerals a finding confirmed by the rover s mossbauer spectrometer spirit also excavated light toned si rich soils these soils have a flat near infrared spectrum with a drop in reflectance from 934 1009 nm that is consistent with free water contained in voids or adsorbed onto the surface of the silica

high resolution stratigraphic correlation of benthic oxygen isotopic records spanning the last 300 000 years abstract in order to compare the response of different oceanographic regions to global climate change very detailed stratigraphic techniques are required the global signal of ice volume changes recorded in the oxygen isotopic composition of foraminifera can provide the tool for developing the necessary high resolution stratigraphy in order to evaluate the resolution of a stratigraphy based on detailed isotopic records two techniques are used to correlate a set of benthic oxygen isotope records from seven piston cores taken in the north and south atlantic the indian and the equatorial and north pacific oceans the first technique was modified from the graphic correlation procedure of shaw 1964 this procedure requires the identification of isotopic events that are correlated from core to core detailed correlations for intervals of the cores between events are provided by a series of straight line segments connecting all common events the second technique developed by martinson et al 1982 uses inverse procedures to define a continuous non linear mapping function that correlates the isotopic records the mapping function maximizes the correlation coefficient between data sets being compared the techniques are independent in that they rely on different criteria for correlating the data series stratigraphic correlations obtained by these procedures are in excellent agreement the mean difference between the correlations is on the order of the sampling intervals of each core and when corrected for sedimentation rates suggests that benthic isotope records from the suite of seven cores can be correlated to a resolution of 2000 to 4000 yrs

silica rich deposits and hydrated minerals at gusev crater mars vis nir spectral characterization and regional mapping abstract the mars exploration rover mer spirit has discovered surprisingly high concentrations of amorphous silica in soil and nodular outcrops in the inner basin of the columbia hills in pancam multispectral observations we find that an absorption feature at the longest pancam wavelength 1009 nm appears to be characteristic of these silica rich materials however spectral analyses of amorphous silica suggest that the 1009 nm spectral feature is not a direct reflection of their silica rich nature based on comparisons with spectral databases we hypothesize that the presence of h 2 o or oh either free as water ice adsorbed or bound in a mineral structure is responsible for the spectral feature observed by pancam the gertrude weise soil which is nearly pure opaline silica may have adsorbed water cold trapped on mineral grains the origin of the 1009 nm pancam feature observed in the silica rich nodular outcrops may result from the presence of additional hydrated minerals specific sulfates halides chlorides sodium silicates carbonates or borates using the 1009 nm feature with other spectral parameters as a hydration signature we have mapped the occurrence of hydrated materials along the extent of spirit s traverse across the columbia hills from west spur to home plate sols 155 1696 we have also mapped this hydration signature across large panoramic images to understand the regional distribution of materials that are spectrally similar to the silica rich soil and nodular outcrops our results suggest that hydrated materials are common in the columbia hills

mars exploration rover athena panoramic camera pancam investigation 1 the panoramic camera pancam investigation is part of the athena science payload launched to mars in 2003 on nasa s twin mars exploration rover mer missions the scientific goals of the pancam investigation are to assess the high resolution morphology topography and geologic context of each mer landing site to obtain color images to constrain the mineralogic photometric and physical properties of surface materials and to determine dust and aerosol opacity and physical properties from direct imaging of the sun and sky pancam also provides mission support measurements for the rovers including sun finding for rover navigation hazard identification and digital terrain modeling to help guide long term rover traverse decisions high resolution imaging to help guide the selection of in situ sampling targets and acquisition of education and public outreach products the pancam optical mechanical and electronics design were optimized to achieve these science and mission support goals pancam is a multispectral stereoscopic panoramic imaging system consisting of two digital cameras mounted on a mast 1 5 m above the martian surface the mast allows pancam to image the full 360 in azimuth and 90 in elevation each pancam camera utilizes a 1024 1024 active imaging area frame transfer ccd detector array the pancam optics have an effective focal length of 43 mm and a focal ratio of f 20 yielding an instantaneous field of view of 0 27 mrad pixel and a field of view of 16 16 each rover s two pancam eyes are separated by 30 cm and have a 1 toe in to provide adequate stereo parallax each eye also includes a small eight position filter wheel to allow surface mineralogic studies multispectral sky imaging and direct sun imaging in the 400 1100 nm wavelength region pancam was designed and calibrated to operate within specifications on mars at temperatures from 55 to 5 c an onboard calibration target and fiducial marks provide the capability to validate the radiometric and geometric calibration on mars

spectral variability among rocks in visible and near infrared multispectral pancam data collected at gusev crater examinations using spectral mixture analysis and related techniques 1 visible and near infrared vnir multispectral observations of rocks made by the mars exploration rover spirit s panoramic camera pancam have been analyzed using a spectral mixture analysis sma methodology scenes have been examined from the gusev crater plains into the columbia hills most scenes on the plains and in the columbia hills could be modeled as three end member mixtures of a bright material rock and shade scenes of rocks disturbed by the rover s rock abrasion tool rat required additional end members in the columbia hills there were a number of scenes in which additional rock end members were required the sma methodology identified relatively dust free areas on undisturbed rock surfaces as well as spectrally unique areas on rat abraded rocks spectral parameters from these areas were examined and six spectral classes were identified these classes are named after a type rock or area and are adirondack lower west spur clovis wishstone peace and watchtower these classes are discriminable based primarily on near infrared nir spectral parameters clovis and watchtower class rocks appear more oxidized than wishstone class rocks and adirondack basalts based on their having higher 535 nm band depths comparison of the spectral parameters of these gusev crater rocks to parameters of glass dominated basaltic tuffs indicates correspondence between measurements of clovis and watchtower classes but divergence for the wishstone class rocks which appear to have a higher fraction of crystalline ferrous iron bearing phases despite a high sulfur content the rock peace has nir properties resembling plains basalts

mineralogy composition and alteration of mars pathfinder rocks and soils evidence from multispectral elemental and magnetic data on terrestrial analogue snc meteorite and pathfinder samples major element multispectral and magnetic properties data were obtained at ares vallis during the mars pathfinder mission to understand the compositional mineralogical and process implications of these data we obtained major element mineralogical and magnetic data for well crystalline and nanophase ferric minerals terrestrial analogue samples with known geologic context and snc meteorites analogue samples include unaltered palagonitic and sulfatetic tephra from mauna kea volcano hydrolytic and acid sulfate alteration steam vent material from kilauea volcano hydrolytic alteration and impactites from meteor crater relithification salient results for mars pathfinder include 1 band depths bd530b and bd600 and the reflectivity ratio r800 r750 are consistent with the dominant ferric mineral being nanophase ferric oxide associated with an unknown amount of h2o and occurring in composite particles along with subordinate amounts of other ferric minerals hematite and hematite plus nanophase goethite are most consistent with the data but maghemite akaganeite schwertmannite and nanophase lepidocrocite are also possible interpretations ferric oxides that are consistently not favored by the data as sole alteration products are jarosites and well crystalline goethite and lepidocrocite 2 the strength of the ferric adsorption edge r750 r445 implies the fe3 fe2 values for pathfinder rock and soil are within the ranges 0 7 3 and 3 20 respectively 3 ferrous silicates are indicated for subsets of pathfinder rocks and soils one subset has a band minimum near 930 nm that can attributed to low ca pyroxene alternatively the band could be a second manifestation of certain ferric oxides including nanophase goethite maghemite akaganeite and schwertmannite another subset has a negative spectral slope from 800 to 1005 nm which could result from the high energy wing of a high ca pyroxene and or olivine band a mixture of bright and dark materials and for rocks thin coatings of bright dust on dark rocks 4 chemical data on pathfinder rocks and soils are consistent with two component mixtures between an andesitic rock with low mgo and so3 concentrations soil free rock and a global basaltic soil with high mgo and so3 concentrations rock free soil pathfinder rock free soil can be modeled as a chemical mixture of snc meteorites and the pathfinder soil free rock 5 pathfinder soil cannot be obtained by chemical alteration of pathfinder rocks by any of the hydrolytic and acid sulfate alteration processes we studied presumably global mixing has obscured and possibly erased the elemental signatures of chemical alteration 6 the strongly magnetic phase in palagonitic and sulfatetic tephra is titanomagnetite and possibly its oxidation product titanomaghemite fe ti spinels the saturation magnetization of the tephra samples 0 5 2 0 am2 kg is at or below the low end of the range inferred for martian dust 4 2 am2 kg implying that lithogenic fe ti spinels are a possible candidate for the martian strongly magnetic phase 7 the predominantly palagonitic spectral signature and magnetic nature of martian soil and dust are consistent with glassy precursors with imbedded fe ti spinel particles comparison with lunar glass production rates suggests that production of sufficient quantities of glassy materials on mars by volcanic and impact processes is sufficient to account for these observations

volcanic ash layers facilitate high resolution sequence stratigraphy at convergent plate margins an example from the plio pleistocene forearc basin fill in the boso peninsula japan abstract in this paper a method is presented for the definition of high resolution siliciclastic depositional sequences in onshore outcrop belts in a forearc basin setting and the development of high frequency depositional sequences in the infill of the plio pleistocene kazusa forearc basin in the boso peninsula of japan in terms of the interaction between forearc tectonics and glacio eustasy is discussed volcanic ash layers are commonly intercalated in siliciclastic successions at convergent plate margins and provide physically defined chronostratigraphic markers the mapping of lateral termination of volcanic ash layers together with the interpretation of depositional facies discontinuities permits the identification of onlap offlap and downlap stratal termination patterns in onshore outcrop belts in particular this type of analysis is useful to identify bounding surfaces in offshore muddy sediments the relative abundance of intercalated volcanic ash layers and their associated pyroclastic volcaniclastic fragments in marine siliciclastic successions is interpreted to correspond to temporal variation in the relative rate of supply of coarse grained terrigenous sediments to a marine environment during a relative sea level cycle in particular transgressive stages are characterized by the reduction of active supply of coarse grained terrigenous sediments to a marine elastic environment and this results in the increase of relative abundance of intercalated volcanic ash layers and their associated volcanogenic lithofacies this kind of sediment is hierarchically identified in response to the development of marine flooding surfaces transgressive systems tracts and transgressive sequence sets in general boundaries of depositional sequences and their component building blocks are interpreted to provide a chronostratigraphic framework for local and regional correlations of siliciclastic successions the mapping of volcanic ash layers can identify diachronous evolution of bounding surfaces and component building blocks of a high frequency depositional sequence in relation to spatial variations in sedimentation rates and basin subsidence which are superimposed by eustatic sea level changes

thermally altered palagonitic tephra a spectral and process analog to the soil and dust of mars we studied six palagonitic soil samples ph 1 through ph 6 which were collected at 30 cm intervals from a lava slab on mauna kea hawaii the samples represent an alteration sequence caused by heating during emplacement of molten lava over a preexisting tephra cone they are both spectral and weathering alteration process analogs to the martian surface techniques employed included visible and near ir spectroscopy mossbauer spectroscopy and magnetic analysis the two samples collected from beyond 90 cm from the slab ph 5 and ph 6 did not see the transient heating event and are composed of coarse grained glassy basaltic hawaiitic particles some of which have been moderately palagonitized since formation of the cone in the late pleistocene the four samples closest to the slab ph 1 through ph 4 have been strongly altered in response to heating during its emplacement their iron oxide mineralogy is dominated by nanophase ferric oxide the sample adjacent to the slab ph 1 which would have seen the highest temperatures has a factor of 3 less h2o and contains crystalline hematite and magnetite in addition to nanophase ferric oxide lesser amounts of magnetite but not hematite are present in samples 30 cm ph 2 and 60 cm ph 3 from the slab the reflectivity spectra of samples ph 2 through ph 4 are similar to spectra of palagonites reported by other workers to be good mars visible to near ir spectral analogs the reflectivity spectrum of ph 1 is an even better spectral analog to mars in that it exhibits absorption features indicative of both nanophase and crystalline ferric oxides similar to several new martian telescopic data sets our sampling site may also be a process analog for mars in that heating episodes by volcanism and or impact cratering could produce crystalline ferric oxides from poorly crystalline palagonitic material thus localized thermal alteration events may provide a volumetrically important mechanism for the palagonitization of basaltic glass and the production of crystalline ferric oxides on mars

sands at gusev crater mars processes environments and the energy associated with the transport and deposition of sand at gusev crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the spirit rover as it crossed the plains and went into the columbia hills fine to medium sand is ubiquitous in ripples and wind drifts most distributions show excess fine material consistent with a predominance of wind erosion over the last 3 8 billion years negative skewness at west valley is explained by the removal of fine sand during active erosion or alternatively by excess accumulation of coarse sand from a local source the coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape their distribution display significant changes in their statistical moments within the 400 m that separate the columbia memorial station from bonneville crater results are consistent with aeolian and or impact deposition while the elongated and rounded shape of the grains forming the ripples as well as their direction of origin could point to ma adim vallis as a possible source for smaller particles on the traverse our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic e g ripples and plains soils and aerographic settings e g wind shadows

age and depositional environment of the dinosaur graveyard at las aguilas southern coahuila ne mexico abstract here we provide a detailed description of the upper campanian sediment succession at las aguilas southern coahuila northeastern mexico including the first absolute age dating for this interval paleoenvironmental reconstructions and taphonomic observations on the abundant dinosaur remains at the locality stratigraphic investigations of the dinosaur bearing succession at the las aguilas vertebrate fossil area near porvenir de jalpa reveal a diverse vertebrate assemblage including dinosaurs crocodilians and turtles new findings in adjacent sites include eusuchian crocodylomorphs four different kinds of turtles dromaeosaurids lambeosaurines pterosaurs and elasmosaurid plesiosaurs strontium isotope measurements on fossil oyster shells provide an absolute age of 73 1 ma for the lower part of the las aguilas section the locality is thus of late campanian age the vertebrate invertebrate and plant materials as well as the sediment structures observed in a 50 m thick predominantly siliciclastic succession of the cerro del pueblo formation suggest deposition in an extensive delta plain environment the facies succession indicates a short termed cyclicity of limnic brackish and shallow marine environments during the late campanian early maastrichtian cerro del pueblo formation with numerous layers containing dinosaur fossil remains resumen aqui damos una descripcion detallada de la sucesion de sedimentos del campaniano superior en las aguilas sur de coahuila noreste de mexico incluyendo la primera datacion absoluta para este intervalo reconstrucciones paleoambientales y observaciones taxonomicas sobre la abundancia de restos de dinosaurios en la localidad investigaciones estratigraficas de los estratos con dinosaurios en el area fosilifera de las aguilas cerca de porvenir de jalpa revelan un ensamblaje vertebrado diverso incluyendo dinosaurios cocodrilos y tortugas nuevos descubrimientos en sitios adyacentes incluyen crocodylomorfos eusuquios cuatro diferentes tipos de tortugas dromaeosauridos lambeosaurinos pterosaurios y plesiosaurios elasmosauridos mediciones de isotopos de estroncio en conchas de ostiones fosiles proveen una edad absoluta de 73 1 millones de anos para la parte inferior de la seccion de las aguilas la localidad es por lo tanto de edad campaniana tardia el material de vertebrados invertebrados y de plantas asi como las estructuras sedimentarias observadas en una sucesion predominantemente siliciclastica de 50 m de la formacion cerro del pueblo sugieren una depositacion en un ambiente de una extensa planicie deltaica la sucesion de facies indica una ciclicidad de periodo corto de ambientes limnicos estuarinos y marinos someros durante el campaniano tardio maastrichtiano temprano de la formacion cerro del pueblo con numerosos estratos conteniendo fosiles de dinosaurios palabras clave las aguilas sucesion de dinosaurios campaniano superior ambientes deposicionales formacion cerro del pueblo coahuila

mineralogy of volcanic rocks in gusev crater mars reconciling mossbauer alpha particle x ray spectrometer and miniature thermal emission spectrometer spectra 1 complete sets of mineral abundances for relatively unaltered volcanic or volcaniclastic rocks in gusev crater have been determined by modeling mossbauer subspectral areas as mineral weight percentages and combining those percentages with the proportions of iron free minerals not detected by mossbauer normative plagioclase apatite and chromite as calculated from alpha particle x ray spectrometer apxs chemical analyses comparisons of synthetic thermal emission spectra calculated for these mineral modes with measured miniature thermal emission spectrometer mini tes spectra for the same rock classes show either good agreements or discrepancies that we attribute to sodic plagioclase compositions or unmodeled sulfate glass or pigeonite the normative compositions of olivine pyroxene and feldspar calculated from apxs data are consistent with spectroscopic constraints on mineral compositions systematic variations between olivine abundances in apxs norms which sample tens of micrometers depth and olivine proportions measured by mossbauer which sample hundreds of micrometers depth support the hypothesis that dissolution of olivine by acidic fluids has occurred on weathered rock surfaces

geochemical properties of rocks and soils in gusev crater mars results of the alpha particle x ray spectrometer from cumberland ridge to home plate 1 geochemical diversity of rocks and soils has been discovered by the alpha particle x ray spectrometer apxs during spirit s journey over husband hill and down into the inner basin from sol 470 to 1368 the apxs continues to operate nominally with no changes in calibration or spectral degradation over the course of the mission germanium has been added to the spirit apxs data set with the confirmation that it occurs at elevated levels in many rocks and soils around home plate twelve new rock classes and two new soil classes have been identified at the spirit landing site since sol 470 on the basis of the diversity in apxs geochemistry the new rock classes are irvine alkaline basalt independence low fe outcrop descartes outcrop similar to independence with higher fe and mn algonquin mafic ultramafic igneous sequence barnhill volcaniclastic sediments enriched in zn cl and ge fuzzy smith high si and ti rock elizabeth mahon high si ni and zn outcrop and rock halley hematite rich outcrop and rock montalva high k hematite rich rock everett high mg magnetite rich rock good question high si low mn rock and torquas high k zn and ni magnetite rich rock new soil classes are gertrude weise very high si soil and eileen dean high mg magnetite rich soil aqueous processes have played a major role in the formation and alteration of rocks and soils on husband hill and in the inner basin

surface albedo observations at gusev crater and meridiani planum mars 1 during the mars exploration rover mission the pancam instrument has periodically acquired large scale panoramic images with its broadband 739 338 nm filter in order to estimate the lambert bolometric albedo of the surface along each rover s traverse in this work we present the full suite of such estimated albedo values measured to date by the spirit and opportunity rovers along their traverses in gusev crater and meridiani planum respectively we include estimated bolometric albedo values of individual surface features e g outcrops dusty plains aeolian bed forms wheel tracks light toned soils and crater walls as well as overall surface averages of the 43 total panoramic albedo data sets acquired to date we also present comparisons to estimated lambert albedo values taken from the mars global surveyor mars orbiter camera moc along the rovers traverses and to the large scale bolometric albedos of the sites from the viking orbiter infrared thermal mapper irtm and mars global surveyor thermal emission spectrometer tes the ranges of pancam derived albedos at gusev crater 0 14 to 0 25 and in meridiani planum 0 10 to 0 18 are in good agreement with irtm tes and moc orbital measurements these data sets will be a useful tool and benchmark for future investigations of albedo variations with time including measurements from orbital instruments like the context camera and high resolution imaging science experiment on mars reconnaissance orbiter long term accurate albedo measurements could also be important for future efforts in climate modeling as well as for studies of active surface processes