544 research outputs found
Jarosite stability on Mars
No full textJarosite, a potassium (sodium) iron sulphate hydrated mineral, has recently been identified on the martian surface by the Opportunity rover. Using recent thermochemical data [Drouet and Navrotsky, 2003, Geochim. Cosmochim. Acta 67, 2063–2076; Forray et al., 2005, Geochim. Cosmochim. Acta, in press], we calculate the equilibrium decomposition curve of jarosite and show that it is thermodynamically stable under most present martian pressures and temperatures. Its stability makes jarosite potentially useful to retain textural, chemical, and isotopic evidence of past history, including possible biological activity, on Mars
Development of life marker chip technology for in-situ life detection on Mars
No full textThe European Space Agency (ESA) is currently developing its flagship Life Detection Mission, ExoMars, which is scheduled to fly to Mars in 2013. The primary goal of this mission is to compliment the Phoenix NASA mission in confirming the presence of organic material on Mars, and, for the first time, analyse this organic material to determine the presence of organic species indicative of presence of past or present Life. One of the proposed Life detection technologies is the Life Marker Chip (LMC), which uses immunoassays with fluorescent readout to detect small organics and proteins in a microarray format within microfluidic channel structures. This PhD thesis encompasses the work done by the author on the development of the SMILE LMC during the period prior to, and during part of the first phase of, the Life Marker Chip Technology Readiness Level Upgrade Study funded by ESA from 2005 and 2007. Cont/d
30-m HRSC DTM Mosaic of Gale Crater, Mars
No full textDigital terrain model (DTM) mosaic of Gale crater, Mars, processed from High-Resolution Stereo Camera (HRSC) stereo images using the modification of DLR-VICAR described by Kim and Muller (2009).
Format: GeoTiff
Projection: Equidistant cylindrical
Datum: Spheroid (r = 3396.190 km)
Bit depth: Float32
Grid-spacing: 30 m/pixel
Terrain reference: 200-m MOLA and HRSC blended global DTM (Fergason et al. 2018)
HRSC source images: H1938_0000, H1927_0000, and H1916_0000The first author is now at Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California. Contact: [email protected]
Analysis of the Mars Northern Seasonal Polar Cap Asymmetry in Conjunction with Recession
No full textThe University of Nevada, Reno Libraries will promptly respond to removal requests related to content that violates intellectual property laws, data protections, or has been uploaded without creator consent. Takedown notices should be directed to our ScholarWolf team ([email protected]) with information about the object, including its full URL and the nature of your complaint.Mars' seasonal polar caps undergo a constant cycling throughout a single Martian year. These processes are dynamic and important aspects that showcase interactions between Mars' weather, atmosphere, and surface activity. The rate at which CO2 sublimates from the seasonal ice sheet and into the atmosphere has been seen to remain fairly consistent between a variety of Mars years through the creation of an inter-annual climatological model. The cap itself, however, has been observed to retreat in an asymmetric fashion. We plan to utilize Mars topography data collected from the Mars Orbiter Laser Altimeter in order to find a link between the observed quicker or slower recession of the seasonal CO2 cap and the local elevation
Altered Basalts from Hawaii as an Analog for Alteration on Mars
No full textThe University of Nevada, Reno Libraries will promptly respond to removal requests related to content that violates intellectual property laws, data protections, or has been uploaded without creator consent. Takedown notices should be directed to our ScholarWolf team ([email protected]) with information about the object, including its full URL and the nature of your complaint.Mars has been a focus of planetary academic research for decades due to relatively new data from spacecraft. Spectral data from both satellite and rover instrumentation have provided identification of a variety of materials. Satellite data have guided future mission plans and deployments by providing coarsely defined areas of interest for up close observation. Recently, spectral data acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) have identified hydrated silicates, carbonates, and serpentines in multiple locations. All of these minerals provide evidence for occurrence of specific surface and crustal processes, many of which can produce habitable environments for simple life. Similar alteration minerals are present in basalt flows from Hawaii in a similar background lithology and present a prime analog for in-depth laboratory study to understand the processes resulting in alteration on Mars. Reflectance spectroscopy can identify minerals by quantifying how light of various wavelengths reflects from mineral crystals. Alteration minerals are generated from secondary processes after a rock forms, and many have particularly distinctive spectral signatures in the visible to short-wave infrared (VIS-SWIR) wavelengths. Past spectral work has already shown significant evidence of the presence of aqueous activity and associated alteration on Mars (Bibring et al., 2006: Milliken et al., 2008: Ehlmann et al, 2009: Ehlmann, Mustard, & Murchie, 2010). Less defined, however, is the genetic source of these alteration minerals. Finding out whether these minerals formed simply as a past product of surface water interaction with exposed basalt, or represent outcrops of alteration due to groundwater or subsurface water-rock interactions offers answers to significant scientific questions related to the planet. Also of interest is past (or possibly present) serpentinization, which (when active) produces magnetite and H2, a possible energy source for aqueous microb
Mars Thermal Inertia and Surface Temperatures by the Mars Climate Sounder
No full textMars Thermal Inertia and Surface Temperatures by the Mars Climate Sounder
Sylvain Piqueux, David M. Kass, Armin Kleinböhl, Marek Slipski, Paul O. Hayne, Daniel J. McCleese, John T. Schofield, Nicholas Heavens
Jet Propulsion Laboratory, California Institute of Technology
4800 Oak Grove Drive
Pasadena, CA 91109
USA
Copyright 2023. All Rights Reserved.
Corresponding author: Sylvain Piqueux
Jet Propulsion Laboratory
M/S 183-301
4800 Oak Grove Drive
Pasadena, CA 91109
USA
[email protected]
Phone: 818-393-9595
Fax: 818-354-2494
Supporting files associated with the paper "Mars Thermal Inertia and Surface Temperatures by the Mars Climate Sounder
Spectral Diversity of Exposed Materials at Meridiani Planum, Mars, via Pancam Aboard the Mars Exploration Rover, Opportunity
No full textPrevious analyses of multispectral data of exposed materials at Meridiani Planum from the Mars Exploration Rover, Opportunity, reported on sampling Pancam spectra for large areas of surface type exposures. In those analyses, the likelihood of spectral mixing from other material types and shadows was influential on the spectral profiles and thus not optimally measuring the spectra of the material type of interest. This study expands on previous efforts by sampling pixels specifically indicative of each material type exposed along the rover's traverse from the landing site in Eagle crater to the 800 m diameter Victoria crater. Careful selection of pixels was done to not include other material types when focusing on sampling each material type, allowing a more detailed analysis of the material types and their classifications. The results of this study conclusively showed that calibration efforts maintained reliability throughout the traverse and over the first four years of the mission, and that the bedrock materials have several sub-classes of light- and dark-toned color, layered and massive, buff and purple colored in false color composites, dust covered, and dust-free exposures. The bedrock sub-classes essentially have similar spectra with slight differences in the visible wavelengths for the buff- and purple-colored bedrock, and a lower Fe signature reported in the dark-toned outcrop. The stratigraphic section of the Burns Fm, laterally and vertically over 10 km and 7 m, respectively, does not exhibit spectral differences indicating the bedrock stratigraphy exposed in the region of the landing site and traverse was deposited in a consistent climatic environment or that the secondary diagenetic effects have overprinted a common mineralogy throughout
Compositional Investigation ofStratigraphic & Morphologic Unitsin the South Polar Ice Deposits of Mars
No full textVariable mixtures of CO2 ice, H2O ice, and dust in volatile exposures at the south pole of Mars influence interactions with the atmosphere that drive their formation, evolution, and eventual preservation as long-term climate records. However, ice composition in the south polar region has not been mapped in sufficient detail to fully track the influence of these dynamic processes and their implications for Mars climate history.This thesis is focused on expanding our understanding of south polar ice composition through a comprehensive analysis of data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Twenty-one spectral endmembers are identified and mapped at up to 18 m/pixel through k-means clustering and random forest classification of localized hyperspectral observations. Those endmembers are then mapped at 90 m/pixel across most of the CO2 ice-dominated south polar residual cap (SPRC) and key exposures of peripheral H2O ice. Evaluations of endmember spectra and associated spatial and temporal trends in classified maps are used to characterize compositional variation through time, across stratigraphic units, and within erosional morphologies. We report new findings that show complex topographic expressions and gradational transitions in the composition of H2O ice-rich deposits, which likely drive erosional processes and the formation of new climate records. Meanwhile, inter-annual variations in CO2 ice-dominated exposures demonstrate that large-scale dust events alter the deposition and retention of seasonal frost cover. Unexpectedly, residual ices outside of the SPRC are found to express CO2 ice signatures even after this seasonal cover is removed. The compositional framework revealed by these results have broad implications for continued research into the mechanisms that shape seasonal and residual ice deposits in this dynamic region
Temporal changes in the geographic distribution, elevation, and potential origin of the Martian outflow channels
No full textPresented at the Lunar and Planetary Institute Workshop, November 15-17, 1993, Houston, Texas.
Observational evidence of outflow channel activity on Mars suggests that water was abundant in the planet's early crust. However, with the decline in the planet's internal heat flow, a freezing front developed within the regolith that propagated downward with time and acted as a thermodynamic sink for crustal H2O. One result of this thermal evolution is that, if the initial inventory of water on Mars was small, the cryosphere may have grown to the point where all the available water was taken up as ground ice. Alternatively, if the inventory of H2O exceeds the current pore volume of the cryosphere, then Mars has always possessed extensive bodies of subpermafrost groundwater. We have investigated the relative age, geographic distribution, elevation, and geologic setting of the outflow channels in an effort to accomplish the following: (1) identify possible modes of origin and evolutionary trends in their formation; (2) gain evidence regarding the duration and spatial distribution of groundwater in the crust; and (3) better constraint estimates of the planetary inventory of H2O.conference proceedingsPublishedGround WaterLunar and Planetary ExplorationThermodynamicsSpatial DistributionHeat TransmissionFreezingRegolithPlanetary GeologyPlanetary CrustsPermafrostMars SurfaceIc
Thermochemistry of yavapaiite KFe(SO4)2: Formation and decomposition
No full textYavapaiite, KFe(SO4)2, is a rare mineral in nature, but its structure is considered as a reference for many synthetic compounds in the alum supergroup. Several authors mention the formation of yavapaiite by heating potassium jarosite above ca. 400°C. To understand the thermal decomposition of jarosite, thermodynamic data for phases in the K-Fe-S-O-(H) system, including yavapaiite, are needed. A synthetic sample of yavapaiite was characterized in this work by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal analysis. Based on X-ray diffraction pattern refinement, the unit cell dimensions for this sample were found to be a = 8.152 ± 0.001 Å, b = 5.151 ± 0.001 Å, c = 7.875 ± 0.001 Å, and β = 94.80°. Thermal decomposition indicates that the final breakdown of the yavapaiite structure takes place at 700°C (first major endothermic peak), but the decomposition starts earlier, around 500°C. The enthalpy of formation from the elements of yavapaiite, KFe(SO4)2, ΔH°f = −2042.8 ± 6.2 kJ/mol, was determined by high-temperature oxide melt solution calorimetry. Using literature data for hematite, corundum, and Fe/Al sulfates, the standard entropy and Gibbs free energy of formation of yavapaiite at 25°C (298 K) were calculated as S°(yavapaiite) = 224.7 ± 2.0 J.mol−1.K−1 and ΔG°f = −1818.8 ± 6.4 kJ/mol. The equilibrium decomposition curve for the reaction jarosite = yavapaiite + Fe2O3 + H2O has been calculated, at pH2O = 1 atm, the phase boundary lies at 219 ± 2°C
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