438 results on '"Wiens, R. C"'
Search Results
402. Geochemical variation in the Stimson formation of Gale crater: Provenance, mineral sorting, and a comparison with modern Martian dunes
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Bedford, C. C., Schwenzer, S., Bridges, J. C., Banham, S., Wiens, R. C., Gasnault, O., Rampe, E. B., Frydenvang, J., Gasda, P. J., Bedford, C. C., Schwenzer, S., Bridges, J. C., Banham, S., Wiens, R. C., Gasnault, O., Rampe, E. B., Frydenvang, J., and Gasda, P. J.
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The Mars Science Laboratory Curiosity rover has encountered both ancient lithified and modern active aeolian dune deposits within Gale crater, providing an opportunity to study how aeolian processes have changed during Gale crater's geological history. This study uses data from the Chemistry and Camera (ChemCam) and Chemistry and Mineralogy (CheMin) instrument suites onboard Curiosity to; (1) constrain the diagenetic processes that lithified and altered the ancient aeolian Stimson formation, (2) investigate whether the geochemical signature in the Stimson formation is consistent with the aeolian mafic-felsic mineral sorting trend identified in the modern Bagnold dune fields in Gale crater, and (3) discuss the provenance of the Stimson sediments, comparing it to those identified in the modern dune and ancient river and lake deposits also analyzed along Curiosity's traverse. The ancient Stimson dune deposits that stratigraphically overlie the Gale fluvio-lacustrine units were analyzed in two locations; the Emerson and the Naukluft plateaus. ChemCam data show that the Stimson formation has subtle variations in MgO, Al2O3, Na2O, and K2O between the two localities. An agglomerative cluster analysis of the constrained Stimson dataset reveals five clusters, four of which relate to different proportions of mafic and felsic minerals analyzed by ChemCam. In general, the cluster analysis shows that the Emerson plateau has a greater proportion of mafic minerals and fewer coarse, felsic grains relative to the Naukluft plateau. This variation in mafic and felsic minerals between localities suggests a southwest to northeast net sediment transport direction due to aeolian mineral sorting dynamics preferentially transporting mafic minerals that are easier to saltate than the elongate, often coarser, felsic minerals. This derived transport direction for the Stimson formation supports that determined b
403. Overview of the Morphology and Chemistry of Diagenetic Features in the Clay‐Rich Glen Torridon Unit of Gale Crater, Mars
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Gasda, Patrick J., Comellas, J., Essunfeld, A., Das, D., Bryk, A. B., Dehouck, E., Schwenzer, S. P., Crossey, L., Herkenhoff, K., Johnson, J. R., Newsom, H., Lanza, N. L., Rapin, W., Goetz, W., Meslin, P.‐Y., Bridges, J. C., Anderson, R., David, G., Turner, S. M. R., Thorpe, M. T., Kah, L., Frydenvang, J., Kronyak, R., Caravaca, G., Ollila, A., Le Mouélic, S., Nellessen, M., Hoffman, M., Fey, D., Cousin, A., Wiens, R. C., Clegg, S. M., Maurice, S., Gasnault, O., Delapp, D., Reyes‐Newell, A., Gasda, Patrick J., Comellas, J., Essunfeld, A., Das, D., Bryk, A. B., Dehouck, E., Schwenzer, S. P., Crossey, L., Herkenhoff, K., Johnson, J. R., Newsom, H., Lanza, N. L., Rapin, W., Goetz, W., Meslin, P.‐Y., Bridges, J. C., Anderson, R., David, G., Turner, S. M. R., Thorpe, M. T., Kah, L., Frydenvang, J., Kronyak, R., Caravaca, G., Ollila, A., Le Mouélic, S., Nellessen, M., Hoffman, M., Fey, D., Cousin, A., Wiens, R. C., Clegg, S. M., Maurice, S., Gasnault, O., Delapp, D., and Reyes‐Newell, A.
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The clay-rich Glen Torridon region of Gale crater, Mars, was explored between sols 2300 and 3007. Here, we analyzed the diagenetic features observed by Curiosity, including veins, cements, nodules, and nodular bedrock, using the ChemCam, Mastcam, and Mars Hand Lens Imager instruments. We discovered many diagenetic features in Glen Torridon, including dark-toned iron- and manganese-rich veins, magnesium- and fluorine-rich linear features, Ca-sulfate cemented bedrock, manganese-rich nodules, and iron-rich strata. We have characterized the chemistry and morphology of these features, which are most widespread in the higher stratigraphic members in Glen Torridon, and exhibit a wide range of chemistries. These discoveries are strong evidence for multiple generations of fluids from multiple chemical endmembers that likely underwent redox reactions to form some of these features. In a few cases, we may be able to use mineralogy and chemistry to constrain formation conditions of the diagenetic features. For example, the dark-toned veins likely formed in warmer, highly alkaline, and highly reducing conditions, while manganese-rich nodules likely formed in oxidizing and circumneutral conditions. We also hypothesize that an initial enrichment of soluble elements, including fluorine, occurred during hydrothermal alteration early in Gale crater history to account for elemental enrichment in nodules and veins. The presence of redox-active elements, including Fe and Mn, and elements required for life, including P and S, in these fluids is strong evidence for habitability of Gale crater groundwater. Hydrothermal alteration also has interesting implications for prebiotic chemistry during the earliest stages of the crater’s evolution and early Mars.
404. The Chemistry and Morphology of Diagenetic Features in Glen Torridon, Gale Crater
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Gasda, P. J., Comellas, J., Essunfeld, A., Das, D., Nellessen, M., Dehouck, E., Anderson, R., Rapin, W., Lanza, N., Meslin, P.-Y., David, G., Crossey, L., Newsom, H., Hoffman, M., Fey, D., Kronyak, R., Frydenvang, J., Bridges, J., Turner, S. M. R., Schwenzer, S. P., Wiens, R. C., Clegg, S., Maurice, S., Gasnault, O., Gasda, P. J., Comellas, J., Essunfeld, A., Das, D., Nellessen, M., Dehouck, E., Anderson, R., Rapin, W., Lanza, N., Meslin, P.-Y., David, G., Crossey, L., Newsom, H., Hoffman, M., Fey, D., Kronyak, R., Frydenvang, J., Bridges, J., Turner, S. M. R., Schwenzer, S. P., Wiens, R. C., Clegg, S., Maurice, S., and Gasnault, O.
405. Geochemical Endmembers preserved in Gale Crater: A tale of two mudstones and their compositional differences according to ChemCam
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Bedford, C. C., Schwenzer, S. P., Bridges, J. C., Wiens, R. C., Rampe, E. B., Frydenvang, J., Gasda, P. J., Bedford, C. C., Schwenzer, S. P., Bridges, J. C., Wiens, R. C., Rampe, E. B., Frydenvang, J., and Gasda, P. J.
406. Evidence for a Diagenetic Origin of Vera Rubin Ridge, Gale Crater, Mars: Summary and Synthesis of Curiosity's Exploration Campaign
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Fraeman, A. A., Edgar, L. A., Rampe, E. B., Thompson, L. M., Frydenvang, J., Fedo, C. M., Catalano, J. G., Dietrich, W. E., Gabriel, T. S. J., Vasavada, A. R., Grotzinger, J. P., L'Haridon, J., Mangold, N., Sun, V. Z., House, C. H., Bryk, A. B., Hardgrove, C., Czarnecki, S., Stack, K. M., Morris, R. V., Arvidson, R. E., Banham, S. G., Bennett, K. A., Bridges, J. C., Edwards, C. S., Fischer, W. W., Fox, V. K., Gupta, S., Horgan, B. H. N., Jacob, S. R., Johnson, J. R., Johnson, S. S., Rubin, D. M., Salvatore, M. R., Schwenzer, S. P., Siebach, K. L., Stein, N. T., Turner, S., Wellington, D. F., Wiens, R. C., Williams, A. J., David, G., Wong, G. M., Fraeman, A. A., Edgar, L. A., Rampe, E. B., Thompson, L. M., Frydenvang, J., Fedo, C. M., Catalano, J. G., Dietrich, W. E., Gabriel, T. S. J., Vasavada, A. R., Grotzinger, J. P., L'Haridon, J., Mangold, N., Sun, V. Z., House, C. H., Bryk, A. B., Hardgrove, C., Czarnecki, S., Stack, K. M., Morris, R. V., Arvidson, R. E., Banham, S. G., Bennett, K. A., Bridges, J. C., Edwards, C. S., Fischer, W. W., Fox, V. K., Gupta, S., Horgan, B. H. N., Jacob, S. R., Johnson, J. R., Johnson, S. S., Rubin, D. M., Salvatore, M. R., Schwenzer, S. P., Siebach, K. L., Stein, N. T., Turner, S., Wellington, D. F., Wiens, R. C., Williams, A. J., David, G., and Wong, G. M.
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This paper provides an overview of the Curiosity rover's exploration at Vera Rubin ridge and summarizes the science results. Vera Rubin ridge (VRR) is a distinct geomorphic feature on lower Aeolis Mons (informally known as Mt. Sharp) that was identified in orbital data based on its distinct texture, topographic expression, and association with a hematite spectral signature. Curiosity conducted extensive remote sensing observations, acquired data on dozens of contact science targets, and drilled three outcrop samples from the ridge, as well as one outcrop sample immediately below the ridge. Our observations indicate that strata composing VRR were deposited in a predominantly lacustrine setting and are part of the Murray formation. The rocks within the ridge are chemically in family with underlying Murray formation strata. Red hematite is dispersed throughout much of the VRR bedrock, and this is the source of the orbital spectral detection. Gray hematite is also present in isolated, gray‐colored patches concentrated towards the upper elevations of VRR, and these gray patches also contain small, dark Fe‐rich nodules. We propose that VRR formed when diagenetic event(s) preferentially hardened rocks, which were subsequently eroded into a ridge by wind. Diagenesis also led to enhanced crystallization and/or cementation that deepened the ferric‐related spectral absorptions on the ridge, which helped make them readily distinguishable from orbit. Results add to existing evidence of protracted aqueous environments at Gale crater and give new insight into how diagenesis shaped Mars’ rock record.
407. Boron and Lithium in Calcium Sulfate Veins: Tracking Precipitation of Diagenetic Materials in Vera Rubin Ridge, Gale Crater
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Das, D., Gasda, P. J., Wiens, R. C., Berlo, K., Leveille, R. J., Frydenvang, J., Mangold, N., Kronyak, R. E., Schwenzer, S. P., Forni, Olivier, Cousin, Agnes, Maurice, S., Gasnault, O., Das, D., Gasda, P. J., Wiens, R. C., Berlo, K., Leveille, R. J., Frydenvang, J., Mangold, N., Kronyak, R. E., Schwenzer, S. P., Forni, Olivier, Cousin, Agnes, Maurice, S., and Gasnault, O.
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The NASA Curiosity rover’s ChemCam instrument suite has detected boron in calcium‐sulfate‐filled fractures throughout the sedimentary strata of Gale crater including Vera Rubin ridge (VRR). The presence of elevated B concentration provides insights into Martian subsurface aqueous processes. In this study we extend the dataset of B in Ca‐sulfate veins across Gale crater, comparing the detection frequency and relative abundances with Li. We report 33 new detections of B within veins analyzed between sols 1548 and 2311 where detections increase in Pettegrove Point and Jura members, which form VRR. The presence of B and Li in the Ca‐sulfate veins is possibly due to dissolution of pre‐existing B in clays of the bedrock by acids or neutral water and redistribution of the elements into the veins. Elevated frequency of B detection in veins of Gale crater correlate with presence of dehydration features such as desiccation cracks, altered clay minerals and detections of evaporites such as Mg‐sulfates, chloride salts in the host rocks. The increased observations of B also coincide with decreased Li concentration in the veins (average Li concentration of veins drops by ~15 ppm). Boron and Li have varying solubilities and Li does not form salts as readily upon dehydration as B, causing it to remain in the solution. So, the weak negative correlation between B and Li may reflect the crystallization sequence during dehydration on Vera Rubin ridge.
408. The SuperCam infrared instrument on the NASA MARS2020 mission: performance and qualification results
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Sodnik, Zoran, Karafolas, Nikos, Cugny, Bruno, Reess, J. -M., Bonafous, Marion, Lapauw, L., Humeau, O., Fouchet, T., Bernardi, P., Cais, Ph., Deleuze, M., Forni, O., Maurice, S., Robinson, S., and Wiens, R. C.
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- 2019
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409. Developing Tailored Data Combination Strategies to Optimize the SuperCam Classification of Carbonate Phases on Mars.
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Veneranda, M., Manrique, J. A., Lopez‐Reyes, G., Julve‐Gonzalez, S., Rull, F., Alvarez Llamas, C., Delgado Pérez, T., Gibbons, E., Clavé, E., Cloutis, E., Huidobro, J., Castro, K., Madariaga, J. M., Randazzo, N., Brown, A., Willis, P., Maurice, S., and Wiens, R. C.
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LASER-induced breakdown spectroscopy , *CARBONATE minerals , *FISHER discriminant analysis , *MARS (Planet) , *PRINCIPAL components analysis , *DISCRIMINANT analysis , *GEOLOGICAL modeling , *NAIVE Bayes classification - Abstract
The SuperCam instrument onboard the Mars 2020 Perseverance rover investigates Martian geological targets by a combination of multiple spectroscopic techniques. As Raman, Visible‐Infrared Spectroscopy, and Laser‐Induced Breakdown Spectroscopy (LIBS) spectra deliver complementary information about the interrogated sample, the multivariate analysis of combined spectroscopic data sets is here proposed as a tool to optimize the SuperCam capability to discriminate mineral phases on Mars. For this purpose, the laboratory study of carbonate phases within the Ca‐Mg‐Fe ternary system were selected as representative case of study. After the characterization of model samples, the discrimination capability of mono analytical Raman, VISIR, and LIBS data sets was evaluated by applying a chemometric approach based on the combination of principal component analysis (for sample clustering) and Linear Discriminant Analysis (for mineral classification). Afterward, the low‐level combination (LL) of Raman, VISIR, and LIBS data was achieved by concatenating their spectra into a single data matrix. The mineral classification achieved by LL data sets outperformed the mono analytical ones, thus proving the complementarity between molecular and elemental spectroscopic techniques. Mineral classification was further improved by using a mid‐level data combination strategy. After evaluating benefits and limitations afforded by the proposed combination strategies, future developments are finally outlined. As such, the final objective of this research line is to develop a classification model based on data combination to optimize the capability of SuperCam in discriminating relevant minerals on Mars, this being a key requirement for the selection of the optimal targets to be cached for the future Mars Sample Return Mission. Plain Language Summary: The SuperCam instrument onboard the Perseverance rover is capable of analyzing Martian rocks and soils by a combination of Laser‐Induced Breakdown Spectroscopy (LIBS), Raman and Visible‐Infrared Spectroscopy (VISIR). Learning from terrestrial applications, the complementary information provided by the three spectroscopic techniques can be correlated to obtain a more accurate interpretation of the analyzed target. This approach could be particularly useful to discriminate carbonates, which are interesting minerals where to look for traces of past life. Having this in mind, several carbonate samples have been analyzed with laboratory Raman, LIBS, and VISIR instrument. After evaluating the advantages and limitations of each technique, their data were merged by using low‐level and mid‐level strategies that were successfully used previous works. This work proved that, when spectra are combined, the discrimination of carbonate phases is more accurate than when each technique is interpreted separately. This suggests the scientific results obtained by SuperCam on Mars could benefit from the development of tailored classification models based on data combination. Key Points: Data combination of Raman, Visible‐Infrared Spectroscopy, and Laser‐Induced Breakdown Spectroscopy spectra collected by SuperCam is proposedLow‐ and mid‐level data combination strategies based on principal component analysis (discrimination) + PC‐Linear Discriminant Analysis (classification are evaluated and compared)The low‐level combination method outperformed the mono analytical discrimination. The mid‐level one further improved the results [ABSTRACT FROM AUTHOR]
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- 2023
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410. Identifying Shocked Feldspar on Mars Using Perseverance Spectroscopic Instruments: Implications for Geochronology Studies on Returned Samples.
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Shkolyar, S., Jaret, S. J., Cohen, B. A., Johnson, J. R., Beyssac, O., Madariaga, J. M., Wiens, R. C., Ollila, A., Holm-Alwmark, S., and Liu, Y.
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GEOLOGICAL time scales , *FELDSPAR , *MARS (Planet) , *RAMAN spectroscopy , *THERMOLUMINESCENCE dating , *LUMINESCENCE , *PLAGIOCLASE , *LUMINESCENCE spectroscopy - Abstract
The Perseverance rover (Mars 2020) mission, the first step in NASA's Mars Sample Return (MSR) program, will select samples for caching based on their potential to improve understanding Mars' astrobiological, geological, geochemical, and climatic evolution. Geochronologic analyses will be among the key measurements planned for returned samples. Assessing a sample's shock history will be critical because shock metamorphism could influence apparent sample age. Shock effects in one Mars-relevant mineral class, plagioclase feldspar, have been well-documented using various spectroscopy techniques (thermal infrared reflectance, emission, and transmission spectroscopy, Raman, and luminescence). A subset of these data will be obtained with the SuperCam and SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instruments onboard Perseverance to inform caching decisions for MSR. Here, we review shock indicators in plagioclase feldspar as revealed in Raman, luminescence, and IR spectroscopy lab data, with an emphasis on Raman spectroscopy. We consider how this information may inform caching decisions for selecting optimal samples for geochronology measurements. We then identify challenges and make recommendations for both in situ measurements performed with SuperCam and SHERLOC and for supporting lab studies to enhance the success of geochronologic analyses after return to Earth. [ABSTRACT FROM AUTHOR]
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- 2022
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411. Helium isotope diffusion in natural diamonds
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Wiens, R. C., Lal, D., Rison, W., and Wacker, J. F.
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- 1994
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412. A 15N-Poor Isotopic Composition for the Solar System As Shown by Genesis Solar Wind Samples.
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Marty, B., Chaussidon, M., Wiens, R. C., Jurewicz, A. J. G., and Burnett, D. S.
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NITROGEN isotopes , *SOLAR wind , *SPACE probes , *LAGRANGIAN points , *IONS , *MATHEMATICAL models , *ATOMIC mass , *DIAMONDS , *CHONDRULES , *JUPITER (Planet) , *SUN - Abstract
The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a 15N/14N ratio of 2.18 0.02 x 10-3 (that is, ≈40% poorer in 15N relative to terrestrial atmosphere). The 15N/14N ratio of the protosolar nebula was 2.27 ± 0.03 x 10-3 which is the lowest 15N/14N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the 15N-depleted components observed in solar system reservoirs. [ABSTRACT FROM AUTHOR]
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- 2011
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413. Alternating wet and dry depositional environments recorded in the stratigraphy of Mount Sharp at Gale crater, Mars.
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Rapin, W., Dromart, G., Rubin, D., Le Deit, L., Mangold, N., Edgar, L. A., Gasnault, O., Herkenhoff, K., Le Mouélic, S., Anderson, R. B., Maurice, S., Fox, V., Ehlmann, B. L., Dickson, J. L., and Wiens, R. C.
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GALE Crater (Mars) , *MARS (Planet) , *CLIMATE change , *FACIES - Abstract
The Curiosity rover is exploring Hesperian-aged stratigraphy in Gale crater, Mars, where a transition from clay-bearing units to a layered sulfate-bearing unit has been interpreted to represent a major environmental transition of unknown character. We present the first description of key facies in the sulfate-bearing unit, recently observed in the distance by the rover, and propose a model for changes in depositional environments. Our results indicate a transition from lacustrine mudstones into thick aeolian deposits, topped by a major deflation surface, above which strata show architectures likely diagnostic of a subaqueous environment. This model offers a reference example of a depositional sequence for layered sulfate-bearing strata, which have been identified from orbit in other locations globally. It differs from the idea of a monotonic Hesperian climate change into long-term aridity on Mars and instead implies a period characterized by multiple transitions between sustained drier and wetter climates. [ABSTRACT FROM AUTHOR]
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- 2021
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414. SuperCam Calibration Targets: Design and Development.
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Manrique, J. A., Lopez-Reyes, G., Cousin, A., Rull, F., Maurice, S., Wiens, R. C., Madsen, M. B., Madariaga, J. M., Gasnault, O., Aramendia, J., Arana, G., Beck, P., Bernard, S., Bernardi, P., Bernt, M. H., Berrocal, A., Beyssac, O., Caïs, P., Castro, C., and Castro, K.
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SuperCam is a highly integrated remote-sensing instrumental suite for NASA’s Mars 2020 mission. It consists of a co-aligned combination of Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), Visible and Infrared Spectroscopy (VISIR), together with sound recording (MIC) and high-magnification imaging techniques (RMI). They provide information on the mineralogy, geochemistry and mineral context around the Perseverance Rover. The calibration of this complex suite is a major challenge. Not only does each technique require its own standards or references, their combination also introduces new requirements to obtain optimal scientific output. Elemental composition, molecular vibrational features, fluorescence, morphology and texture provide a full picture of the sample with spectral information that needs to be co-aligned, correlated, and individually calibrated. The resulting hardware includes different kinds of targets, each one covering different needs of the instrument. Standards for imaging calibration, geological samples for mineral identification and chemometric calculations or spectral references to calibrate and evaluate the health of the instrument, are all included in the SuperCam Calibration Target (SCCT). The system also includes a specifically designed assembly in which the samples are mounted. This hardware allows the targets to survive the harsh environmental conditions of the launch, cruise, landing and operation on Mars during the whole mission. Here we summarize the design, development, integration, verification and functional testing of the SCCT. This work includes some key results obtained to verify the scientific outcome of the SuperCam system. [ABSTRACT FROM AUTHOR]
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- 2020
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415. Pre-launch radiometric calibration of the infrared spectrometer onboard SuperCam for the Mars2020 rover.
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Royer, Clément, Poulet, F., Reess, J.-M., Pilorget, C., Hamm, V., Fouchet, T., Maurice, S., Forni, O., Bernardi, P., Montmessin, F., Lapauw, L., Parisot, J., Bonafous, M., Gasnault, O., and Wiens, R. C.
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MARTIAN surface , *CALIBRATION , *SURFACE analysis , *TEMPERATURE detectors , *SIGNAL-to-noise ratio , *IR spectrometers , *RADIOMETRY - Abstract
Near-infrared spectroscopy has become a well-known remote sensing technique for the surface characterization of planetary objects. Among them, Mars was observed in the past by three imaging spectrometers from orbit. The Infrared Spectrometer/SuperCam instrument performs near-infrared spectroscopy from the martian surface for the first time, with a 1.15 mrad field of view, in the 1.3 µm–2.6 µm range, enabling the identification of a variety of mafic and altered minerals. Before integration aboard the rover, the spectrometer underwent a calibration campaign. Here, we report the radiometric and linearity responses of the instrument, including the optical and thermal setups used to perform them over its nominal range of operations, in terms of instrument detector temperatures and spectral range. These responses were constrained by accuracy requirements (20% in absolute radiometry, 1% in relative). The derived instrument transfer function fits within these requirements (<15% in absolute and <0.8% in relative) and shall be used to calculate the expected instrumental signal-to-noise ratio for typical observation scenarios of mineral mixtures expected to be found in the Jezero crater, and ultimately to retrieve the spectral properties of the regions of interest observed by the rover. [ABSTRACT FROM AUTHOR]
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- 2020
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416. Magnesium isotopes of the bulk solar wind from Genesis diamond‐like carbon films.
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Jurewicz, A. J. G., Rieck, K. D., Hervig, R., Burnett, D. S., Wadhwa, M., Olinger, C. T., Wiens, R. C., Laming, J. M., Guan, Y., Huss, G. R., Reisenfeld, D. B., and Williams, P.
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DIAMOND-like carbon , *MAGNESIUM isotopes , *SILICON films , *ISOTOPIC fractionation , *SOLAR photosphere , *CHROMIUM isotopes , *SOLAR wind , *DATA reduction - Abstract
NASA's Genesis Mission returned solar wind (SW) to the Earth for analysis to derive the composition of the solar photosphere from solar material. SW analyses control the precision of the derived solar compositions, but their ultimate accuracy is limited by the theoretical or empirical models of fractionation due to SW formation. Mg isotopes are "ground truth" for these models since, except for CAIs, planetary materials have a uniform Mg isotopic composition (within ≤1‰) so any significant isotopic fractionation of SW Mg is primarily that of SW formation and subsequent acceleration through the corona. This study analyzed Mg isotopes in a bulk SW diamond‐like carbon (DLC) film on silicon collector returned by the Genesis Mission. A novel data reduction technique was required to account for variable ion yield and instrumental mass fractionation (IMF) in the DLC. The resulting SW Mg fractionation relative to the DSM‐3 laboratory standard was (−14.4‰, −30.2‰) ± (4.1‰, 5.5‰), where the uncertainty is 2ơ SE of the data combined with a 2.5‰ (total) error in the IMF determination. Two of the SW fractionation models considered generally agreed with our data. Their possible ramifications are discussed for O isotopes based on the CAI nebular composition of McKeegan et al. (2011). [ABSTRACT FROM AUTHOR]
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- 2020
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417. Fluidized-sediment pipes in Gale crater, Mars, and possible Earth analogs.
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Rubin, David M., Fairén, A. G., Martínez-Frías, J., Frydenvang, J., Gasnault, O., Gelfenbaum, G., Goetz, W., Grotzinger, J. P., Le Mouélic, S., Mangold, N., Newsom, H., Oehler, D. Z., Rapin, W., Schieber, J., and Wiens, R. C.
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FLUIDIZATION , *SEDIMENTARY structures , *SEDIMENTATION & deposition , *AQUEOUS solutions , *PIPE - Abstract
Since landing in Gale crater, the Mars Science Laboratory rover Curiosity has traversed fluvial, lacustrine, and eolian sedimentary rocks that were deposited within the crater ~3.6 to 3.2 b.y. ago. Here we describe structures interpreted to be pipes formed by vertical movement of fluidized sediment. Like many pipes on Earth, those in Gale crater are more resistant to erosion than the host rock; they form near other pipes, dikes, or deformed sediment; and some contain internal concentric or eccentric layering. These structures provide new evidence of the importance of subsurface aqueous processes in shaping the near-surface geology of Mars. [ABSTRACT FROM AUTHOR]
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- 2017
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418. The Petrochemistry of Jake_M: A Martian Mugearite.
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Stolper, E. M., Baker, M. B., Newcombe, M. E., Schmidt, M. E., Treiman, A. H., Cousin, A., Dyar, M. D., Fisk, M. R., Gellert, R., King, P. L., Leshin, L., Maurice, S., McLennan, S. M., Minitti, M. E., Perrett, G., Rowland, S., Sautter, V., and Wiens, R. C.
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ROCK analysis , *OUTCROPS (Geology) , *ASTRONAUTICAL instruments , *X-ray spectrometers , *ALPHA rays , *EARTH analogs to Martian geology - Abstract
"Jake_M," the first rock analyzed by the Alpha Particle X-ray Spectrometer instrument on the Curiosity rover, differs substantially in chemical composition from other known martian igneous rocks: It is alkaline (>15% normative nepheline) and relatively fractionated. Jake_M is compositionally similar to terrestrial mugearites, a rock type typically found at ocean islands and continental rifts. By analogy with these comparable terrestrial rocks, Jake_M could have been produced by extensive fractional crystallization of a primary alkaline or transitional magma at elevated pressure, with or without elevated water contents. The discovery of Jake_M suggests that alkaline magmas may be more abundant on Mars than on Earth and that Curiosity could encounter even more fractionated alkaline rocks (for example, phonolites and trachytes). [ABSTRACT FROM AUTHOR]
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- 2013
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419. Soil Diversity and Hydration as Observed by ChemCam at Gale Crater, Mars.
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Meslin, P.-Y., Gasnault, O., Forni, O., Schröder, S., Cousin, A., Berger, G., Clegg, S. M., Lasue, J., Maurice, S., Sautter, V., Le Mouélic, S., Wiens, R. C., Fabre, C., Goetz, W., Bish, D., Mangold, N., Ehlmann, B., Lanza, N., Harri, A.-M., and Anderson, R.
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ASTRONAUTICAL instruments , *HYDRATION , *SOIL chemistry , *SOIL classification , *MARTIAN craters , *WATER of hydration , *MARTIAN geology - Abstract
The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration. [ABSTRACT FROM AUTHOR]
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- 2013
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420. Martian Fluvial Conglomerates at Gale Crater.
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Williams, R. M. E., Grotzinger, J. P., Dietrich, W. E., Gupta, S., Sumner, D. Y., Wiens, R. C., Mangold, N., Malin, M. C., Edgett, K. S., Maurice, S., Forni, O., Gasnault, O., Ollila, A., Newsom, H. E., Dromart, G., Palucis, M. C., Yingst, R. A., Anderson, R. B., Herkenhoff, K. E., and Le Mouélic, S.
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FLUVIAL geomorphology , *MARTIAN craters , *CONGLOMERATE , *FELDSPATHOID , *SEDIMENT transport , *PEBBLES , *SAND , *HYDRAULICS , *MARTIAN geology , *WATER on Mars - Abstract
Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers. [ABSTRACT FROM AUTHOR]
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- 2013
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421. The sound of a Martian dust devil.
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Murdoch N, Stott AE, Gillier M, Hueso R, Lemmon M, Martinez G, Apéstigue V, Toledo D, Lorenz RD, Chide B, Munguira A, Sánchez-Lavega A, Vicente-Retortillo A, Newman CE, Maurice S, de la Torre Juárez M, Bertrand T, Banfield D, Navarro S, Marin M, Torres J, Gomez-Elvira J, Jacob X, Cadu A, Sournac A, Rodriguez-Manfredi JA, Wiens RC, and Mimoun D
- Subjects
- Dust analysis, Wind, Atmosphere, Extraterrestrial Environment, Mars
- Abstract
Dust devils (convective vortices loaded with dust) are common at the surface of Mars, particularly at Jezero crater, the landing site of the Perseverance rover. They are indicators of atmospheric turbulence and are an important lifting mechanism for the Martian dust cycle. Improving our understanding of dust lifting and atmospheric transport is key for accurate simulation of the dust cycle and for the prediction of dust storms, in addition to being important for future space exploration as grain impacts are implicated in the degradation of hardware on the surface of Mars. Here we describe the sound of a Martian dust devil as recorded by the SuperCam instrument on the Perseverance rover. The dust devil encounter was also simultaneously imaged by the Perseverance rover's Navigation Camera and observed by several sensors in the Mars Environmental Dynamics Analyzer instrument. Combining these unique multi-sensorial data with modelling, we show that the dust devil was around 25 m large, at least 118 m tall, and passed directly over the rover travelling at approximately 5 m s
-1 . Acoustic signals of grain impacts recorded during the vortex encounter provide quantitative information about the number density of particles in the vortex. The sound of a Martian dust devil was inaccessible until SuperCam microphone recordings. This chance dust devil encounter demonstrates the potential of acoustic data for resolving the rapid wind structure of the Martian atmosphere and for directly quantifying wind-blown grain fluxes on Mars., (© 2022. The Author(s).)- Published
- 2022
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422. Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars.
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Farley KA, Stack KM, Shuster DL, Horgan BHN, Hurowitz JA, Tarnas JD, Simon JI, Sun VZ, Scheller EL, Moore KR, McLennan SM, Vasconcelos PM, Wiens RC, Treiman AH, Mayhew LE, Beyssac O, Kizovski TV, Tosca NJ, Williford KH, Crumpler LS, Beegle LW, Bell JF 3rd, Ehlmann BL, Liu Y, Maki JN, Schmidt ME, Allwood AC, Amundsen HEF, Bhartia R, Bosak T, Brown AJ, Clark BC, Cousin A, Forni O, Gabriel TSJ, Goreva Y, Gupta S, Hamran SE, Herd CDK, Hickman-Lewis K, Johnson JR, Kah LC, Kelemen PB, Kinch KB, Mandon L, Mangold N, Quantin-Nataf C, Rice MS, Russell PS, Sharma S, Siljeström S, Steele A, Sullivan R, Wadhwa M, Weiss BP, Williams AJ, Wogsland BV, Willis PA, Acosta-Maeda TA, Beck P, Benzerara K, Bernard S, Burton AS, Cardarelli EL, Chide B, Clavé E, Cloutis EA, Cohen BA, Czaja AD, Debaille V, Dehouck E, Fairén AG, Flannery DT, Fleron SZ, Fouchet T, Frydenvang J, Garczynski BJ, Gibbons EF, Hausrath EM, Hayes AG, Henneke J, Jørgensen JL, Kelly EM, Lasue J, Le Mouélic S, Madariaga JM, Maurice S, Merusi M, Meslin PY, Milkovich SM, Million CC, Moeller RC, Núñez JI, Ollila AM, Paar G, Paige DA, Pedersen DAK, Pilleri P, Pilorget C, Pinet PC, Rice JW Jr, Royer C, Sautter V, Schulte M, Sephton MA, Sharma SK, Sholes SF, Spanovich N, St Clair M, Tate CD, Uckert K, VanBommel SJ, Yanchilina AG, and Zorzano MP
- Abstract
The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding that the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Magnesium-iron carbonates along grain boundaries indicate reactions with carbon dioxide-rich water under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks have been stored aboard Perseverance for potential return to Earth.
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- 2022
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423. An olivine cumulate outcrop on the floor of Jezero crater, Mars.
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Liu Y, Tice MM, Schmidt ME, Treiman AH, Kizovski TV, Hurowitz JA, Allwood AC, Henneke J, Pedersen DAK, VanBommel SJ, Jones MWM, Knight AL, Orenstein BJ, Clark BC, Elam WT, Heirwegh CM, Barber T, Beegle LW, Benzerara K, Bernard S, Beyssac O, Bosak T, Brown AJ, Cardarelli EL, Catling DC, Christian JR, Cloutis EA, Cohen BA, Davidoff S, Fairén AG, Farley KA, Flannery DT, Galvin A, Grotzinger JP, Gupta S, Hall J, Herd CDK, Hickman-Lewis K, Hodyss RP, Horgan BHN, Johnson JR, Jørgensen JL, Kah LC, Maki JN, Mandon L, Mangold N, McCubbin FM, McLennan SM, Moore K, Nachon M, Nemere P, Nothdurft LD, Núñez JI, O'Neil L, Quantin-Nataf CM, Sautter V, Shuster DL, Siebach KL, Simon JI, Sinclair KP, Stack KM, Steele A, Tarnas JD, Tosca NJ, Uckert K, Udry A, Wade LA, Weiss BP, Wiens RC, Williford KH, and Zorzano MP
- Abstract
The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigated the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We found that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multistage cooling of a thick magma body.
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- 2022
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424. Homogeneity assessment of the SuperCam calibration targets onboard rover perseverance.
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Madariaga JM, Aramendia J, Arana G, Castro K, Gómez-Nubla L, Fdez-Ortiz de Vallejuelo S, Garcia-Florentino C, Maguregui M, Manrique JA, Lopez-Reyes G, Moros J, Cousin A, Maurice S, Ollila AM, Wiens RC, Rull F, Laserna J, Garcia-Baonza V, Madsen MB, Forni O, Lasue J, Clegg SM, Robinson S, Bernardi P, Brown AJ, Caïs P, Martinez-Frias J, Beck P, Bernard S, Bernt MH, Beyssac O, Cloutis E, Drouet C, Dromart G, Dubois B, Fabre C, Gasnault O, Gontijo I, Johnson JR, Medina J, Meslin PY, Montagnac G, Sautter V, Sharma SK, Veneranda M, and Willis PA
- Subjects
- Calibration, Minerals analysis, Spectrum Analysis, Raman methods, Extraterrestrial Environment chemistry, Mars
- Abstract
The SuperCam instrument, onboard the Perseverance rover (Mars 2020 mission) is designed to perform remote analysis on the Martian surface employing several spectroscopic techniques such as Laser Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman (TRR), Time-Resolved Fluorescence (TRF) and Visible and Infrared (VISIR) reflectance. In addition, SuperCam also acquires high-resolution images using a color remote micro-imager (RMI) as well as sounds with its microphone. SuperCam has three main subsystems, the Mast Unit (MU) where the laser for chemical analysis and collection optics are housed, the Body Unit (BU) where the different spectrometers are located inside the rover, and the SuperCam Calibration Target (SCCT) located on the rover's deck to facilitate calibration tests at similar ambient conditions as the analyzed samples. To perform adequate calibrations on Mars, the 22 mineral samples included in the complex SCCT assembly must have a very homogeneous distribution of major and minor elements. The analysis and verification of such homogeneity for the 5-6 replicates of the samples included in the SCCT has been the aim of this work. To verify the physic-chemical homogeneity of the calibration targets, micro Energy Dispersive X-ray Fluorescence (EDXRF) imaging was first used on the whole surface of the targets, then the relative abundances of the detected elements were computed on 20 randomly distributed areas of 100 × 100 μm. For those targets showing a positive Raman response, micro-Raman spectroscopy imaging was performed on the whole surface of the targets at a resolution of 100 × 100 μm. The %RSD values (percent of relative standard deviation of mean values) for the major elements measured with EDXRF were compared with similar values obtained by two independent LIBS set-ups at spot sizes of 300 μm in diameter. The statistical analysis showed which elements were homogeneously distributed in the 22 mineral targets of the SCCT, providing their uncertainty values for further calibration. Moreover, nine of the 22 targets showed a good Raman response and their mineral distributions were also studied. Those targets can be also used for calibration purposes of the Raman part of SuperCam using the wavenumbers of their main Raman bands proposed in this work., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2022
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425. In situ recording of Mars soundscape.
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Maurice S, Chide B, Murdoch N, Lorenz RD, Mimoun D, Wiens RC, Stott A, Jacob X, Bertrand T, Montmessin F, Lanza NL, Alvarez-Llamas C, Angel SM, Aung M, Balaram J, Beyssac O, Cousin A, Delory G, Forni O, Fouchet T, Gasnault O, Grip H, Hecht M, Hoffman J, Laserna J, Lasue J, Maki J, McClean J, Meslin PY, Le Mouélic S, Munguira A, Newman CE, Rodríguez Manfredi JA, Moros J, Ollila A, Pilleri P, Schröder S, de la Torre Juárez M, Tzanetos T, Stack KM, Farley K, and Williford K
- Abstract
Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat
1 , (2) the speed of sound varies at the surface with frequency2,3 and (3) high-frequency waves are strongly attenuated with distance in CO2 (refs.2-4 ). However, theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here, using Perseverance microphone recordings, we present the first characterization of the acoustic environment on Mars and pressure fluctuations in the audible range and beyond, from 20 Hz to 50 kHz. We find that atmospheric sounds extend measurements of pressure variations down to 1,000 times smaller scales than ever observed before, showing a dissipative regime extending over five orders of magnitude in energy. Using point sources of sound (Ingenuity rotorcraft, laser-induced sparks), we highlight two distinct values for the speed of sound that are about 10 m s-1 apart below and above 240 Hz, a unique characteristic of low-pressure CO2 -dominated atmosphere. We also provide the acoustic attenuation with distance above 2 kHz, allowing us to explain the large contribution of the CO2 vibrational relaxation in the audible range. These results establish a ground truth for the modelling of acoustic processes, which is critical for studies in atmospheres such as those of Mars and Venus., (© 2022. The Author(s).)- Published
- 2022
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426. Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars.
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Mangold N, Gupta S, Gasnault O, Dromart G, Tarnas JD, Sholes SF, Horgan B, Quantin-Nataf C, Brown AJ, Le Mouélic S, Yingst RA, Bell JF, Beyssac O, Bosak T, Calef F 3rd, Ehlmann BL, Farley KA, Grotzinger JP, Hickman-Lewis K, Holm-Alwmark S, Kah LC, Martinez-Frias J, McLennan SM, Maurice S, Nuñez JI, Ollila AM, Pilleri P, Rice JW Jr, Rice M, Simon JI, Shuster DL, Stack KM, Sun VZ, Treiman AH, Weiss BP, Wiens RC, Williams AJ, Williams NR, and Williford KH
- Abstract
Observations from orbital spacecraft have shown that Jezero crater on Mars contains a prominent fan-shaped body of sedimentary rock deposited at its western margin. The Perseverance rover landed in Jezero crater in February 2021. We analyze images taken by the rover in the 3 months after landing. The fan has outcrop faces, which were invisible from orbit, that record the hydrological evolution of Jezero crater. We interpret the presence of inclined strata in these outcrops as evidence of deltas that advanced into a lake. In contrast, the uppermost fan strata are composed of boulder conglomerates, which imply deposition by episodic high-energy floods. This sedimentary succession indicates a transition from sustained hydrologic activity in a persistent lake environment to highly energetic short-duration fluvial flows.
- Published
- 2021
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427. Brine-driven destruction of clay minerals in Gale crater, Mars.
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Bristow TF, Grotzinger JP, Rampe EB, Cuadros J, Chipera SJ, Downs GW, Fedo CM, Frydenvang J, McAdam AC, Morris RV, Achilles CN, Blake DF, Castle N, Craig P, Des Marais DJ, Downs RT, Hazen RM, Ming DW, Morrison SM, Thorpe MT, Treiman AH, Tu V, Vaniman DT, Yen AS, Gellert R, Mahaffy PR, Wiens RC, Bryk AB, Bennett KA, Fox VK, Millken RE, Fraeman AA, and Vasavada AR
- Abstract
Mars' sedimentary rock record preserves information on geological (and potential astrobiological) processes that occurred on the planet billions of years ago. The Curiosity rover is exploring the lower reaches of Mount Sharp, in Gale crater on Mars. A traverse from Vera Rubin ridge to Glen Torridon has allowed Curiosity to examine a lateral transect of rock strata laid down in a martian lake ~3.5 billion years ago. We report spatial differences in the mineralogy of time-equivalent sedimentary rocks <400 meters apart. These differences indicate localized infiltration of silica-poor brines, generated during deposition of overlying magnesium sulfate-bearing strata. We propose that destabilization of silicate minerals driven by silica-poor brines (rarely observed on Earth) was widespread on ancient Mars, because sulfate deposits are globally distributed., (Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)
- Published
- 2021
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428. Evidence for a Diagenetic Origin of Vera Rubin Ridge, Gale Crater, Mars: Summary and Synthesis of Curiosity 's Exploration Campaign.
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Fraeman AA, Edgar LA, Rampe EB, Thompson LM, Frydenvang J, Fedo CM, Catalano JG, Dietrich WE, Gabriel TSJ, Vasavada AR, Grotzinger JP, L'Haridon J, Mangold N, Sun VZ, House CH, Bryk AB, Hardgrove C, Czarnecki S, Stack KM, Morris RV, Arvidson RE, Banham SG, Bennett KA, Bridges JC, Edwards CS, Fischer WW, Fox VK, Gupta S, Horgan BHN, Jacob SR, Johnson JR, Johnson SS, Rubin DM, Salvatore MR, Schwenzer SP, Siebach KL, Stein NT, Turner SMR, Wellington DF, Wiens RC, Williams AJ, David G, and Wong GM
- Abstract
This paper provides an overview of the Curiosity rover's exploration at Vera Rubin ridge (VRR) and summarizes the science results. VRR is a distinct geomorphic feature on lower Aeolis Mons (informally known as Mount Sharp) that was identified in orbital data based on its distinct texture, topographic expression, and association with a hematite spectral signature. Curiosity conducted extensive remote sensing observations, acquired data on dozens of contact science targets, and drilled three outcrop samples from the ridge, as well as one outcrop sample immediately below the ridge. Our observations indicate that strata composing VRR were deposited in a predominantly lacustrine setting and are part of the Murray formation. The rocks within the ridge are chemically in family with underlying Murray formation strata. Red hematite is dispersed throughout much of the VRR bedrock, and this is the source of the orbital spectral detection. Gray hematite is also present in isolated, gray-colored patches concentrated toward the upper elevations of VRR, and these gray patches also contain small, dark Fe-rich nodules. We propose that VRR formed when diagenetic event(s) preferentially hardened rocks, which were subsequently eroded into a ridge by wind. Diagenesis also led to enhanced crystallization and/or cementation that deepened the ferric-related spectral absorptions on the ridge, which helped make them readily distinguishable from orbit. Results add to existing evidence of protracted aqueous environments at Gale crater and give new insight into how diagenesis shaped Mars' rock record., (©2020. The Authors.)
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- 2020
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429. Spectral, Compositional, and Physical Properties of the Upper Murray Formation and Vera Rubin Ridge, Gale Crater, Mars.
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Jacob SR, Wellington DF, Bell JF 3rd, Achilles C, Fraeman AA, Horgan B, Johnson JR, Maurice S, Peters GH, Rampe EB, Thompson LM, and Wiens RC
- Abstract
During 2018 and 2019, the Mars Science Laboratory Curiosity rover investigated the chemistry, morphology, and stratigraphy of Vera Rubin ridge (VRR). Using orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars, scientists attributed the strong 860 nm signal associated with VRR to the presence of red crystalline hematite. However, Mastcam multispectral data and CheMin X-ray diffraction (XRD) measurements show that the depth of the 860 nm absorption is negatively correlated with the abundance of red crystalline hematite, suggesting that other mineralogical or physical parameters are also controlling the 860 nm absorption. Here, we examine Mastcam and ChemCam passive reflectance spectra from VRR and other locations to link the depth, position, and presence or absence of iron-related mineralogic absorption features to the XRD-derived rock mineralogy. Correlating CheMin mineralogy to spectral parameters showed that the ~860 nm absorption has a strong positive correlation with the abundance of ferric phyllosilicates. New laboratory reflectance measurements of powdered mineral mixtures can reproduce trends found in Gale crater. We hypothesize that variations in the 860 nm absorption feature in Mastcam and ChemCam observations of VRR materials are a result of three factors: (1) variations in ferric phyllosilicate abundance due to its ~800-1,000 nm absorption; (2) variations in clinopyroxene abundance because of its band maximum at ~860 nm; and (3) the presence of red crystalline hematite because of its absorption centered at 860 nm. We also show that relatively small changes in Ca-sulfate abundance is one potential cause of the erosional resistance and geomorphic expression of VRR., (©2020. The Authors.)
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- 2020
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430. Synergistic Ground and Orbital Observations of Iron Oxides on Mt. Sharp and Vera Rubin Ridge.
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Fraeman AA, Johnson JR, Arvidson RE, Rice MS, Wellington DF, Morris RV, Fox VK, Horgan BHN, Jacob SR, Salvatore MR, Sun VZ, Pinet P, Bell JF 3rd, Wiens RC, and Vasavada AR
- Abstract
Visible/short-wave infrared spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show absorptions attributed to hematite at Vera Rubin ridge (VRR), a topographic feature on northwest Mt. Sharp. The goals of this study are to determine why absorptions caused by ferric iron are strongly visible from orbit at VRR and to improve interpretation of CRISM data throughout lower Mt. Sharp. These goals are achieved by analyzing coordinated CRISM and in situ spectral data along the Curiosity Mars rover's traverse. VRR bedrock within areas that have the deepest ferric absorptions in CRISM data also has the deepest ferric absorptions measured in situ. This suggests strong ferric absorptions are visible from orbit at VRR because of the unique spectral properties of VRR bedrock. Dust and mixing with basaltic sand additionally inhibit the ability to measure ferric absorptions in bedrock stratigraphically below VRR from orbit. There are two implications of these findings: (1) Ferric absorptions in CRISM data initially dismissed as noise could be real, and ferric phases are more widespread in lower Mt. Sharp than previously reported. (2) Patches with the deepest ferric absorptions in CRISM data are, like VRR, reflective of deeper absorptions in the bedrock. One model to explain this spectral variability is late-stage diagenetic fluids that changed the grain size of ferric phases, deepening absorptions. Curiosity's experience highlights the strengths of using CRISM data for spectral absorptions and associated mineral detections and the caveats in using these data for geologic interpretations and strategic path planning tools., (©2020. The Authors.)
- Published
- 2020
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431. Hydrogen Variability in the Murray Formation, Gale Crater, Mars.
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Thomas NH, Ehlmann BL, Rapin W, Rivera-Hernández F, Stein NT, Frydenvang J, Gabriel T, Meslin PY, Maurice S, and Wiens RC
- Abstract
The Mars Science Laboratory (MSL) Curiosity rover is exploring the Murray formation, a sequence of heterolithic mudstones and sandstones recording fluvial deltaic and lake deposits that comprise over 350 m of sedimentary strata within Gale crater. We examine >4,500 Murray formation bedrock points, employing recent laboratory calibrations for ChemCam laser-induced breakdown spectroscopy H measurements at millimeter scale. Bedrock in the Murray formation has an interquartile range of 2.3-3.1 wt.% H
2 O, similar to measurements using the Dynamic Albedo of Neutrons and Sample Analysis at Mars instruments. However, specific stratigraphic intervals include high H targets (6-18 wt.% H2 O) correlated with Si, Mg, Ca, Mn, or Fe, indicating units with opal, hydrated Mg sulfates, hydrated Ca sulfates, Mn-enriched units, and akageneite or other iron oxyhydroxides, respectively. One stratigraphic interval with higher hydrogen is the Sutton Island unit and Blunts Point unit contact, where higher hydrogen is associated with Fe-rich, Ca-rich, and Mg-rich points. A second interval with higher hydrogen occurs in the Vera Rubin ridge portion of the Murray formation, where higher hydrogen is associated with Fe-rich, Ca-rich, and Si-rich points. We also observe trends in the H signal with grain size, separate from chemical variation, whereby coarser-grained rocks have higher hydrogen. Variability in the hydrogen content of rocks points to a history of water-rock interaction at Gale crater that included changes in lake water chemistry during Murray formation deposition and multiple subsequent groundwater episodes., (©2020 The Authors.)- Published
- 2020
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432. Mars Extant Life: What's Next? Conference Report.
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Carrier BL, Beaty DW, Meyer MA, Blank JG, Chou L, DasSarma S, Des Marais DJ, Eigenbrode JL, Grefenstette N, Lanza NL, Schuerger AC, Schwendner P, Smith HD, Stoker CR, Tarnas JD, Webster KD, Bakermans C, Baxter BK, Bell MS, Benner SA, Bolivar Torres HH, Boston PJ, Bruner R, Clark BC, DasSarma P, Engelhart AE, Gallegos ZE, Garvin ZK, Gasda PJ, Green JH, Harris RL, Hoffman ME, Kieft T, Koeppel AHD, Lee PA, Li X, Lynch KL, Mackelprang R, Mahaffy PR, Matthies LH, Nellessen MA, Newsom HE, Northup DE, O'Connor BRW, Perl SM, Quinn RC, Rowe LA, Sauterey B, Schneegurt MA, Schulze-Makuch D, Scuderi LA, Spilde MN, Stamenković V, Torres Celis JA, Viola D, Wade BD, Walker CJ, Wiens RC, Williams AJ, Williams JM, and Xu J
- Subjects
- Caves, Computer Simulation, Ice, Space Flight, Exobiology, Extraterrestrial Environment, Mars
- Abstract
On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic possibility that Mars hosts indigenous microbial life. A powerful theme that permeated the conference is that the key to the search for martian extant life lies in identifying and exploring refugia ("oases"), where conditions are either permanently or episodically significantly more hospitable than average. Based on our existing knowledge of Mars, conference participants highlighted four potential martian refugium (not listed in priority order): Caves, Deep Subsurface, Ices, and Salts. The conference group did not attempt to reach a consensus prioritization of these candidate environments, but instead felt that a defensible prioritization would require a future competitive process. Within the context of these candidate environments, we identified a variety of geological search strategies that could narrow the search space. Additionally, we summarized a number of measurement techniques that could be used to detect evidence of extant life (if present). Again, it was not within the scope of the conference to prioritize these measurement techniques-that is best left for the competitive process. We specifically note that the number and sensitivity of detection methods that could be implemented if samples were returned to Earth greatly exceed the methodologies that could be used at Mars. Finally, important lessons to guide extant life search processes can be derived both from experiments carried out in terrestrial laboratories and analog field sites and from theoretical modeling.
- Published
- 2020
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433. DETERMINING THE ELEMENTAL AND ISOTOPIC COMPOSITION OF THE PRESOLAR NEBULA FROM GENESIS DATA ANALYSIS: THE CASE OF OXYGEN.
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Laming JM, Heber VS, Burnett DS, Guan Y, Hervig R, Huss GR, Jurewicz AJG, Koeman-Shields EC, McKeegan KD, Nittler L, Reisenfeld DB, Rieck KD, Wang J, Wiens RC, and Woolum DS
- Abstract
We compare element and isotopic fractionations measured in solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in the chromosphere and conservation of the first adiabatic invariant in the low corona. Generally good agreement is found, suggesting that these factors are consistent with the process of solar wind fractionation. Based on bulk wind measurements, we also consider in more detail the isotopic and elemental abundances of O. We find mild support for an O abundance in the range 8.75 - 8.83, with a value as low as 8.69 disfavored. A stronger conclusion must await solar wind regime specific measurements from the Genesis samples.
- Published
- 2017
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434. Redox stratification of an ancient lake in Gale crater, Mars.
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Hurowitz JA, Grotzinger JP, Fischer WW, McLennan SM, Milliken RE, Stein N, Vasavada AR, Blake DF, Dehouck E, Eigenbrode JL, Fairén AG, Frydenvang J, Gellert R, Grant JA, Gupta S, Herkenhoff KE, Ming DW, Rampe EB, Schmidt ME, Siebach KL, Stack-Morgan K, Sumner DY, and Wiens RC
- Subjects
- Oxidation-Reduction, Geologic Sediments chemistry, Lakes, Mars
- Abstract
In 2012, NASA's Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Finally, a late phase of geochemical modification by saline fluids is recognized., (Copyright © 2017, American Association for the Advancement of Science.)
- Published
- 2017
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435. A habitable fluvio-lacustrine environment at Yellowknife Bay, Gale crater, Mars.
- Author
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Grotzinger JP, Sumner DY, Kah LC, Stack K, Gupta S, Edgar L, Rubin D, Lewis K, Schieber J, Mangold N, Milliken R, Conrad PG, DesMarais D, Farmer J, Siebach K, Calef F 3rd, Hurowitz J, McLennan SM, Ming D, Vaniman D, Crisp J, Vasavada A, Edgett KS, Malin M, Blake D, Gellert R, Mahaffy P, Wiens RC, Maurice S, Grant JA, Wilson S, Anderson RC, Beegle L, Arvidson R, Hallet B, Sletten RS, Rice M, Bell J 3rd, Griffes J, Ehlmann B, Anderson RB, Bristow TF, Dietrich WE, Dromart G, Eigenbrode J, Fraeman A, Hardgrove C, Herkenhoff K, Jandura L, Kocurek G, Lee S, Leshin LA, Leveille R, Limonadi D, Maki J, McCloskey S, Meyer M, Minitti M, Newsom H, Oehler D, Okon A, Palucis M, Parker T, Rowland S, Schmidt M, Squyres S, Steele A, Stolper E, Summons R, Treiman A, Williams R, and Yingst A
- Subjects
- Bays, Carbon analysis, Geologic Sediments analysis, Geologic Sediments classification, Hydrogen analysis, Hydrogen-Ion Concentration, Iron analysis, Iron chemistry, Nitrogen analysis, Oxidation-Reduction, Oxygen analysis, Phosphorus analysis, Salinity, Sulfur analysis, Sulfur chemistry, Exobiology, Extraterrestrial Environment, Mars, Water
- Abstract
The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus were measured directly as key biogenic elements; by inference, phosphorus is assumed to have been available. The environment probably had a minimum duration of hundreds to tens of thousands of years. These results highlight the biological viability of fluvial-lacustrine environments in the post-Noachian history of Mars.
- Published
- 2014
- Full Text
- View/download PDF
436. Elemental geochemistry of sedimentary rocks at Yellowknife Bay, Gale crater, Mars.
- Author
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McLennan SM, Anderson RB, Bell JF 3rd, Bridges JC, Calef F 3rd, Campbell JL, Clark BC, Clegg S, Conrad P, Cousin A, Des Marais DJ, Dromart G, Dyar MD, Edgar LA, Ehlmann BL, Fabre C, Forni O, Gasnault O, Gellert R, Gordon S, Grant JA, Grotzinger JP, Gupta S, Herkenhoff KE, Hurowitz JA, King PL, Le Mouélic S, Leshin LA, Léveillé R, Lewis KW, Mangold N, Maurice S, Ming DW, Morris RV, Nachon M, Newsom HE, Ollila AM, Perrett GM, Rice MS, Schmidt ME, Schwenzer SP, Stack K, Stolper EM, Sumner DY, Treiman AH, VanBommel S, Vaniman DT, Vasavada A, Wiens RC, and Yingst RA
- Subjects
- Bays, Calcium Sulfate analysis, Calcium Sulfate chemistry, Chlorine analysis, Chlorine chemistry, Ferrosoferric Oxide analysis, Ferrosoferric Oxide chemistry, Halogens analysis, Halogens chemistry, Hydrogen-Ion Concentration, Iron analysis, Iron chemistry, Magnesium analysis, Magnesium chemistry, Silicates analysis, Silicates chemistry, Water chemistry, Exobiology, Extraterrestrial Environment chemistry, Geologic Sediments chemistry, Mars
- Abstract
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.
- Published
- 2014
- Full Text
- View/download PDF
437. A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples.
- Author
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Marty B, Chaussidon M, Wiens RC, Jurewicz AJ, and Burnett DS
- Abstract
The Genesis mission sampled solar wind ions to document the elemental and isotopic compositions of the Sun and, by inference, of the protosolar nebula. Nitrogen was a key target element because the extent and origin of its isotopic variations in solar system materials remain unknown. Isotopic analysis of a Genesis Solar Wind Concentrator target material shows that implanted solar wind nitrogen has a (15)N/(14)N ratio of 2.18 ± 0.02 × 10(-3) (that is, ≈40% poorer in (15)N relative to terrestrial atmosphere). The (15)N/(14)N ratio of the protosolar nebula was 2.27 ± 0.03 × 10(-3), which is the lowest (15)N/(14)N ratio known for solar system objects. This result demonstrates the extreme nitrogen isotopic heterogeneity of the nascent solar system and accounts for the (15)N-depleted components observed in solar system reservoirs.
- Published
- 2011
- Full Text
- View/download PDF
438. Combined remote LIBS and Raman spectroscopy at 8.6m of sulfur-containing minerals, and minerals coated with hematite or covered with basaltic dust.
- Author
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Sharma SK, Misra AK, Lucey PG, Wiens RC, and Clegg SM
- Subjects
- Calcium Carbonate chemistry, Dust analysis, Ferric Compounds chemistry, Lasers, Minerals chemistry, Silicates chemistry, Spectrum Analysis, Raman, Sulfur chemistry
- Abstract
Combined remote laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy investigations at a distance of 8.6m have been carried out in air and under a simulated Martian atmosphere of 933Pa (7Torr) CO(2) on calcite (CaCO(3)), gypsum (CaSO(4).2H(2)O), and elemental sulfur (S), and LIBS investigations on chalcopyrite (CuFeS(2)) and pyrite (FeS(2)). Both Raman and LIBS techniques have also been used sequentially in air on hematite-coated calcite crystals and on a sample of anhydrite covered with basaltic dust. These experiments demonstrate that by using a frequency-doubled Nd:YAG pulsed laser co-radiating 1064 nm and 532 nm laser beams with a 5x beam expander, it is possible to measure simultaneously both the Raman and LIBS spectra of calcite, gypsum and elemental sulfur by adjusting the laser power electronically. The spectra of calcite, gypsum, and elemental sulfur contain fingerprint Raman lines; however, it was not possible to measure the remote Raman spectra of pyrite and chalcopyrite because of low intensities of Raman lines. In the cases of CuFeS(2), FeS(2), and elemental sulfur, S atomic emission lines in the LIBS spectra were detected only in 7Torr of CO(2) pressure and not in air. No S atomic emission lines were detected for gypsum in air or in CO(2). In the case of coated/dusted minerals, it was possible to remove the coating or dust with the focused LIBS laser and measure the Raman spectra of subsurface minerals with a 532 nm laser excitation. The complementary nature of these two techniques is highlighted and discussed.
- Published
- 2007
- Full Text
- View/download PDF
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