A5004531975- Planetary Science and Exploration
- Astro and Planetary Science
- Paleontology and Stratigraphy of Fossils
- Space Exploration and Technology
- Chemical Synthesis and Characterization
- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Radioactivity and Radon Measurements
- Spaceflight effects on biology
- Algal biology and biofuel production
- Atmospheric and Environmental Gas Dynamics
- Marine and environmental studies
- Geological and Geochemical Analysis
- Marine and coastal ecosystems
- Mine drainage and remediation techniques
- Biocrusts and Microbial Ecology
- Clay minerals and soil interactions
- Crystal Structures and Properties
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Space Science and Extraterrestrial Life
- Science Education and Pedagogy
- Science Education and Perceptions
University of Nevada, Las Vegas
2016-2025
College of Southern Nevada
2024
Nevada System of Higher Education
2010
University of New Mexico
1997-1999
Abstract Meteorites represent the only samples available for study on Earth of a number planetary bodies. The minerals within meteorites therefore hold key to addressing numerous questions about our solar system. Of particular interest is Ca-phosphate mineral merrillite, anhydrous end-member merrillite–whitlockite solid solution series. For example, nature merrillite in Martian has been interpreted as evidence water-limited late-stage melts. However, recent research apatite same suggests...
Abstract Martian soils are critically important for understanding the history of Mars, past potentially habitable environments, returned samples, and future human exploration. This study examines soil crusts on floor Jezero crater encountered during initial phases Mars 2020 mission. Soil surface have been observed at other locations, starting with two Viking Lander missions. Rover observations show that also common across crater, revealed in 45 101 locations where rover wheels disturbed...
Abstract The Perseverance rover has sampled mm‐size lithic fragments containing olivine likely from at least two source regions the surface of an inactive megaripple surface, and fine‐grained material to a depth ∼4–6 cm. Some grains lack coherent diffraction pattern measured by PIXL, consistent with presence poorly ordered secondary phases that have been altered. Analysis these materials on Earth will allow examination experienced aqueous, potentially habitable environments could contain...
With long-term missions to Mars and beyond that would not allow resupply, a self-sustaining Bioregenerative Life Support System (BLSS) is essential. Algae are promising candidates for BLSS due their completely edible biomass, fast growth rates ease of handling. Extremophilic algae such as snow halophilic may also be especially suited because ability grow under extreme conditions. However, indicated from over 50 prior space studies examining algal growth, little known about the at close...
Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and possible repositories the preservation of organic matter. Although matter has detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic indigenous igneous hydrothermal reduced carbon. We conducted synthesis experiments motivated by hypothesis that some clay mineral formation may occurred under oxidized conditions conducive to destruction...
This paper reviews the phosphate phases in meteorites and those measured by landed spacecraft, what they reveal about past igneous aqueous conditions on Mars, important implications for potential prebiotic chemistry, habitability, biosignatures that could be detected samples returned from Mars. A review of 378 martian as 2023 indicate two most common minerals Mars meteorites, merrillite apatites, apatite composition is largely F- Cl-rich, with shergottites containing more OH. The...
Merrillite [Ca9NaMg(PO4)7] occurs as a dominant primary Ca-phosphate mineral in martian meteorites and therefore presumably also on Mars. The is an important phase exploring differences geologic processes between Earth Mars, has astrobiological implications due to its potential role significant source of the bio-essential nutrient phosphate. does not occur terrestrially discrete phase, making it difficult obtain for Mars-relevant studies. It can, however, be synthesized from similar...
Abundant evidence indicates that significant surface and near-surface liquid water has existed on Mars in the past. Evaluating potential for habitable environments requires an understanding of chemical physical conditions prevailed such aqueous environments. Among geological features may hold past environmental are weathering profiles, as those phosphorus-rich Wishstone-class rocks Gusev Crater. The profiles these indicate a Ca-phosphate mineral been lost during interactions. high phosphorus...
Abstract— Olivine from Martian meteorite Allan Hills (ALH) 84001 occurs as clusters within orthopyroxene adjacent to fractures containing disrupted carbonate globules and feldspathic shock glass. The inclusions are irregular in shape range size ∼40 μm submicrometer. Some of the elongate boudinage‐like. olivine grains sharp contact with enclosing often contain small chromite. exhibits a very limited composition Fo 65 66 (n = 25). δ 18 O values analyzed by ion microprobe +4.3 +5.3‰...
Bobdownsite, IMA number 2008-037, was approved as a new mineral by the Commission on New Minerals, Nomenclature and Classification (CNMNC) fluorine end-member of whitlockite. The type locality bobdownsite is in Big Fish River, Yukon, Canada, reported to be first with essential monofluorophosphate (PO3F2–). specimen has been reinvestigated electron probe microanalysis (EPMA), our data indicate that abundances are below detection mineral. In addition, we conducted detailed analysis from gas...
The systematics of Co and Ni in olivine from six Apollo 12 basalts were studied by SIMS techniques correlated with major minor element data obtained the electron microprobe.Our results, together previous studies, demonstrate that one these (12009) was extruded, as a liquid, onto lunar surface parental to five other cumulates (12075, 12020, 12018, 12040, 12035).The concentrations zoned phenocrysts behave expected for highly compatible initial estimated D ϭ 9.9.On hand, vary hardly at all show...
Snow algae growth and mineral dust deposition are both known to strongly decrease snow albedo. Previous work has shown is enhanced in the presence of trace nutrient-containing minerals. Increased with aridification due climate change may therefore additionally enhance growth. Here we performed batch experiments a alga (Chloromonas brevispina) bacteria co-culture minerals andradite (Ca3.0(Fe0.6,Al0.43)2(SiO4)3), olivine (Mg1.8Fe0.2SiO4), quartz (SiO2), observe differences attachment surfaces...
Impact is a dominant process acting on the surfaces of planetary bodies and major that modifies physical chemical nature materials atmosphere-free once volcanic activity has ceased. Elements with relatively high volatilities are readily mobilized during impact. HASP (high alumina, silica poor) compositions thought to be generated by impact-induced volatilization processes moon. The Al/Si ratio believed result preferential loss SiO 2 relative Al O 3 . Here we report SIMS analyses for glass...
This study compares high resolution forward models of natural gamma-ray background with that measured by aerial surveys. The ability to predict variations in radiation levels should prove useful for those engaged measuring anthropogenic contributions the purpose emergency response and homeland security operations. are based on geologic maps remote sensing multi-spectral imagery combined two different sources data: 1) bedrock geochemical data (uranium, potassium thorium concentrations)...
Under the assumption that cosmic rays are of extragalactic origin above 1018 eV it is shown presence 2.7K black body radiation may lead to a detectable flux very energetic gamma rays.
The availability of terrestrial sites that are martian analogs allows researchers to investigate Mars using knowledge gained on Earth. Among the analog for is Craters Moon National Monument (COTM) in Idaho, U.S.A. home over 60 basalt lava flows, many which have been dated from 2050 18 340 years before present (y.b.p.). Following previous authors, we examined chemistry and petrogenesis COTM basalts compared basaltic rocks, meteorites, meteorite clasts, then results chemical weathering flows....
Mining activities can lead to an exacerbated enrichment of metal concentrations. Pollution by metal(loid)s in arid regions has been little elucidated. This study assessed the transport and mobilization trace elements environment under two ephemeral wash systems originating from processed tailing materials Valley Wells Smelter, California (USA). Overall, factors evidence a significant increase South Wash compared North Wash. The Principal Component Analysis demonstrates that Cd-Cu is...
Phosphate is an essential nutrient for life on Earth, present in adenosine triphosphate (ATP), deoxyribonucleic acid (DNA), ribonucleic (RNA), and phospholipid membranes. Phosphorus does not have a significant volatile phase, its release from minerals therefore critical to bioavailability. Organic ligands can enhance phosphate relative inorganic solutions, phosphorus depletion paleosols has consequently been used as signature of the presence secreted by terrestrial organisms early Earth. We...
<title>Abstract</title> Phosphorus is an essential component for life, and in-situ identification of phosphate minerals that formed in aqueous conditions directly contributes toward one the main goals Mars 2020 Perseverance rover: to seek signs ancient habitable environments. In Jezero crater, proximity science analyses within a conglomerate outcrop, “Onahu” demonstrate presence rare Fe3+-bearing (likely beraunite, metavivianite, ferrolaueite, and/or santabarbaraite) embedded carbonate-rich...
Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic natural sources radioactivity. There is a relationship between radioactivity geology the past this has been used to predict from aerial survey. The purpose project develop method radiologic exposure rate geologic materials by creating high resolution background model. intention be emergency response scenario where radiation environment...