A5056536765- Planetary Science and Exploration
- Astro and Planetary Science
- Space Science and Extraterrestrial Life
- Space Exploration and Technology
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Paleontology and Stratigraphy of Fossils
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Aeolian processes and effects
- Marine and environmental studies
- Methane Hydrates and Related Phenomena
- Geological Studies and Exploration
- Spaceflight effects on biology
- Calibration and Measurement Techniques
- Isotope Analysis in Ecology
- Microbial Community Ecology and Physiology
- Mineral Processing and Grinding
- Spacecraft and Cryogenic Technologies
- Geomagnetism and Paleomagnetism Studies
- Space exploration and regulation
- Impact of Light on Environment and Health
- Infrared Target Detection Methodologies
- Geochemistry and Elemental Analysis
- Geothermal Energy Systems and Applications
Arizona State University
2013-2023
Woods Hole Oceanographic Institution
2023
Marine Biological Laboratory
2023
University of Calgary
2023
Max Planck Institute for Chemistry
2023
Alberta Biodiversity Monitoring Institute
2023
Earth and Space Research
1997-2019
University of Guelph
2008
Johnson Space Center
2008
Cornell University
2003-2008
Emissivity spectra (1670–200 cm −1 ) from the Mars Global Surveyor Thermal Emission Spectrometer (MGS‐TES) show significant differences between bright and dark surfaces, allowing further investigation of their physical mineralogical character. TES surfaces (albedo ≥0.2) typically lower emissivity at high wavenumbers (>1300 than that <0.2). The opposite behavior is evident in low (<560 ), where have higher ones. These trends are consistent with spectral silicate materials varying...
Mineral deposits on the martian surface can elucidate ancient environmental conditions planet. Opaline silica (as much as 91 weight percent SiO2) have been found in association with volcanic materials by Mars rover Spirit. The are present both light-toned soils and bedrock. We interpret these to formed under hydrothermal therefore be strong indicators of a former aqueous environment. This discovery is important for understanding past habitability because environments Earth support thriving...
The Thermal Emission Imaging System (THEMIS) on Mars Odyssey has produced infrared to visible wavelength images of the martian surface that show lithologically distinct layers with variable thickness, implying temporal changes in processes or environments during after their formation. Kilometer-scale exposures bedrock are observed; elsewhere airfall dust completely mantles over thousands square kilometers. compositional variations at 100-meter scales, for example, an exposure olivine-rich...
Decades of speculation about a warmer, wetter Mars climate in the planet's first billion years postulate denser CO2-rich atmosphere than at present. Such an should have led to formation outcrops rich carbonate minerals, for which evidence has been sparse. Using Exploration Rover Spirit, we now identified magnesium-iron (16 34 weight percent) Columbia Hills Gusev crater. Its composition approximates average globules martian meteorite ALH 84001. The probably precipitated from carbonate-bearing...
The Miniature Thermal Emission Spectrometer (Mini-TES) on Opportunity investigated the mineral abundances and compositions of outcrops, rocks, soils at Meridiani Planum. Coarse crystalline hematite olivine-rich basaltic sands were observed as predicted from orbital TES spectroscopy. Outcrops aqueous origin are composed 15 to 35% by volume magnesium calcium sulfates [a high-silica component modeled a combination glass, feldspar, sheet silicates (approximately 20 30%)], hematite; only minor...
Abstract The Mars rover Spirit encountered outcrops and regolith composed of opaline silica (amorphous SiO 2 · n H O) in an ancient volcanic hydrothermal setting Gusev crater. An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was suggested previously. However, the potential significance characteristic nodular mm-scale digitate structures not recognized. Here we report remarkably similar features within active spring/geyser discharge channels...
A library of thermal infrared spectra silicate, carbonate, sulfate, phosphate, halide, and oxide minerals has been prepared for comparison to obtained from planetary Earth‐orbiting spacecraft, airborne instruments, laboratory measurements. The emphasis in developing this obtain pure samples specific minerals. All were hand processed analyzed composition purity. majority are 710–1000 μm particle size fractions, chosen minimize effects. Spectral acquisition follows a method described...
Water played a major role in the formation and alteration of rocks soils Columbia Hills. The extent ranges from moderate to extensive. Five distinct rock compositional classes were identified; order for degree is Watchtower ≅ Clovis > Wishstone Peace Backstay. rover's wheels uncovered one unusual soil (Paso Robles) that most S‐rich material encountered. class have compositions similar Gusev plains but with higher Mg, Cl, Br lower Ca Zn; high Al, Ti, P low Cr Ni; has Mg S Na, K; Backstay...
Rocks on the floor of Gusev crater are basalts uniform composition and mineralogy. Olivine, only mineral to have been identified or inferred from data by all instruments Spirit rover, is especially abundant in these rocks. These picritic similar many respects certain Martian meteorites (olivine‐phyric shergottites). The olivine megacrysts both intermediate compositions, with modal abundances ranging up 20–30%. Associated minerals include low‐calcium high‐calcium pyroxenes, plagioclase...
The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and MiniâThermal Emission Spectrometer (Mini-TES) spectra suggest that all of these are similar but have variable coatings dust mantles. Magnified images brushed abraded rock surfaces show alteration rinds veins. Rock interiors contain â¤25% megacrysts. Chemical analyses by the Alpha Particle X-ray consistent with picritic basalts, containing normative olivine,...
Previous descriptions of thermal emission spectroscopy have presented techniques that vary in accuracy and reproducibility. Contributions energy from the instrument environment are major calibration factors limit emissivity determination. Reproducibility is related to stability these quantities. Sample temperature determination also a significant factor arriving at accurate emissivity. All which impact measurement using an interferometric spectrometer with uncooled detector isolated examined...
Light‐toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences grouped into four types on basis of geomorphic settings. At three major exposures, light‐toned are hydrous and sulfate‐rich. The spatial distributions distinct salty vary substantially: with centimeter‐scaled heterogeneities Paso Robles, Dead Sea, Shredded, Champagne‐Penny, a well‐mixed nature for occurring near summit Husband Hill, relatively...
[1] The presence of outcrops and soil (regolith) rich in opaline silica (∼65–92 wt % SiO2) association with volcanic materials adjacent to the “Home Plate” feature Gusev crater is evidence for hydrothermal conditions. The Spirit rover has supplied a diverse set observations that are used here better understand formation activity, abundance, fate water first system be explored situ on Mars. We apply spectral, chemical, morphological, textural, stratigraphic assess whether was produced by acid...
Home Plate is a layered plateau in Gusev crater on Mars. It composed of clastic rocks moderately altered alkali basalt composition, enriched some highly volatile elements. A coarsegrained lower unit lies under finer-grained upper unit. Textural observations indicate that the strata were emplaced an explosive event, and geochemical considerations favor volcanic origin over impact origin. The likely represents accumulation pyroclastic materials, whereas may represent eolian reworking same materials.
Opportunity has investigated in detail rocks on the rim of Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate presence Fe +3 -rich smectites. The are associated with fine-grained, layered containing spherules diagenetic or impact origin. overlain by breccias, and both units cut calcium sulfate veins precipitated from fluids that circulated after impact. Compositional data for fractures suggest formation Al-rich smectites aqueous leaching. Evidence is thus...
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 flanks Columbia Hills. Chemical analyses indicate that these mildly alkaline basalt, trachybasalt, tephrite, respectively. Their mineralogy consists Na‐ K‐rich feldspar(s), low‐ high‐Ca pyroxenes, ferroan olivine, Fe‐Ti (and possibly Cr) oxides, phosphate, glass. The texture is consistent a pyroclastic...
The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class is a poorly sorted clastic that undergone substantial aqueous alteration. We interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials. Wishstone also distinctive chemical composition high Ti and P low Cr. may pyroclastic or impact origin. Peace sedimentary material composed ultramafic sand grains cemented significant quantities...
The most plausible models for the origin and evolution of a unique geologic unit in Meridiani Planum, Mars, are low‐temperature precipitation Fe oxides/oxyhydroxides from standing water, circulating fluids hydrothermal origin, or thermal oxidation magnetite‐rich ash. Analysis Odyssey Thermal Emission Imaging System (THEMIS) infrared visible images, together with MGS TES, MOLA, MOC data, has provided additional insight into region. hematite at was likely derived oxyhydroxide precursor such as...
Complete sets of mineral abundances for relatively unaltered volcanic or volcaniclastic rocks in Gusev Crater have been determined by modeling Mössbauer subspectral areas as weight percentages, and combining those percentages with the proportions iron‐free minerals not detected (normative plagioclase, apatite, chromite, calculated from Alpha Particle X‐Ray Spectrometer (APXS) chemical analyses). Comparisons synthetic thermal emission spectra these modes measured Miniature Thermal Emission...
We used a suite of techniques, including those emulating compositional data sets obtained from Mars orbit and obtainable at the surface, to examine aqueous alteration basaltic rocks Iceland as mineralogic geochemical analog for Noachian environments on Mars. A sample was collected laboratory measurement (1) whole‐rock visible/near‐infrared (VNIR) reflectance thermal infrared (TIR) emission spectra; (2) VNIR TIR spectra particle‐size separates derived bulk rock materials extracted...
The origin and age of opaline silica deposits discovered by the Spirit rover adjacent to Home Plate feature in Columbia Hills Gusev crater remains debated, part because their proximity sulfur-rich soils. Processes related fumarolic activity hot springs and/or geysers are leading candidates. Both processes known produce on Earth, but with differences composition, morphology, texture, stratigraphy. Here, we incorporate new existing observations region from field laboratory work address...
Reduced weathering rates due to the lack of liquid water and significantly greater typical surface ages should result in a higher density meteorites on Mars compared Earth. Several were identified among rocks investigated during Opportunity's traverse across sandy Meridiani plains. Heat Shield Rock is IAB iron meteorite has been officially recognized as “Meridiani Planum.” Barberton olivine‐rich contains metallic Fe form kamacite, suggesting meteoritic origin. It chemically most consistent...