C. N. Achilles
A5065828715- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Space Science and Extraterrestrial Life
- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Clay minerals and soil interactions
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Spaceflight effects on biology
- Mineralogy and Gemology Studies
- Aeolian processes and effects
- Spacecraft and Cryogenic Technologies
- X-ray Diffraction in Crystallography
- Biocrusts and Microbial Ecology
- Archaeology and ancient environmental studies
- Advanced X-ray Imaging Techniques
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Star Formation Studies
- Spacecraft Design and Technology
- Microbial Community Ecology and Physiology
- Iron oxide chemistry and applications
Goddard Space Flight Center
2018-2024
University of Maryland, College Park
2022-2023
Universities Space Research Association
2018-2021
University of Arizona
2016-2018
Indiana University Indianapolis
2015
Johnson Space Center
2013-2015
Indiana University Bloomington
2014-2015
Indiana University – Purdue University Indianapolis
2015
Jacobs (United States)
2010-2013
Oak Ridge Associated Universities
2013
Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, sulfides, amorphous material, trioctahedral smectites. smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. Cumberland both ~13.2 angstroms. larger suggests a partially chloritized magnesium facilitating H2O retention. Basaltic minerals...
The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian bedform in Gale crater. Analysis with Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite, pigeonite, minor K-feldspar, magnetite, quartz, anhydrite, hematite, ilmenite. phases are present at, or near, detection limits. also contains 27 ± 14 weight percent amorphous material, likely containing multiple Fe 3+ -...
The Rocknest aeolian deposit is similar to features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. fraction of sand <150 micrometers in size contains ~55% crystalline material consistent with a basaltic heritage ~45% x-ray amorphous material. component iron-rich silicon-poor host volatiles (water, oxygen, sulfur dioxide, carbon chlorine) detected Sample Analysis at instrument fine-grained nanophase oxide first described from soils MERs. similarity between materials...
The Mars Science Laboratory Curiosity rover has been traversing strata at the base of Aeolis Mons (informally known as Mount Sharp) since September 2014. Murray formation makes up lowest exposed Sharp group and is composed primarily finely laminated lacustrine mudstone intercalated with rare crossbedded sandstone that prodeltaic or fluvial in origin. We report on first three drilled samples from formation, measured Pahrump Hills section. Rietveld refinements FULLPAT full pattern fitting...
A principal goal of the Mars Science Laboratory (MSL) rover Curiosity is to identify and characterize past habitable environments on Mars. Determination mineralogical chemical composition Martian rocks soils constrains their formation alteration pathways, providing information climate habitability through time. The CheMin X-ray diffraction (XRD) fluorescence (XRF) instrument MSL will return accurate identifications quantitative phase abundances for scooped soil samples drilled rock powders...
Significance Tridymite, a SiO 2 mineral that crystallizes at low pressures and high temperatures (>870 °C) from high-SiO materials, was detected concentrations in sedimentary mudstone Gale crater, Mars. Mineralogy abundance were determined by X-ray diffraction using the Chemistry instrument on Mars Science Laboratory rover Curiosity . Terrestrial tridymite is commonly associated with silicic volcanism where high-silica magmas prevail, so this occurrence first situ mineralogical evidence...
Abstract The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X‐ray diffraction (XRD) in MSL Curiosity rover. From Rietveld refinements its XRD pattern, contains following: sanidine (21% weight, ~Or 95 ); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); percent levels others including ilmenite, fluorapatite, bassanite. mass balance on Alpha Proton Spectrometer...
Clay minerals found in Gale crater, Mars, record surficial chemical weathering and changing conditions an ancient lake.
The Mars Science Laboratory (MSL) rover Curiosity has documented a section of fluvio-lacustrine strata at Yellowknife Bay (YKB), an embayment on the floor Gale crater, approximately 500 m east Bradbury landing site. X-ray diffraction (XRD) data and evolved gas analysis (EGA) from CheMin SAM instruments show that two powdered mudstone samples (named John Klein Cumberland) drilled Sheepbed member this succession contain up to ~20 wt% clay minerals. A trioctahedral smectite, likely ferrian...
Analyses by the CheMin X-ray diffraction instrument on Mars Science Laboratory show that gypsum, bassanite, and anhydrite are common minerals at Gale crater. Warm conditions (~6 to 30 °C) within drive gypsum dehydration bassanite; measured surface temperatures modeled temperature depth profiles indicate near-equatorial warm-season heating can also cause bassanite. By accounting for instrumental effects we able quantify in situ abundances of Ca-sulfate phases sedimentary rocks eolian sands...
Abstract The Mars Science Laboratory rover, Curiosity, is using a comprehensive scientific payload to explore rocks and soils in Gale crater, Mars. Recent investigations of the Bagnold Dune Field provided first situ assessment an active dune on Chemistry Mineralogy (CheMin) X‐ray diffraction instrument Curiosity performed quantitative mineralogical analyses <150 μm size fraction Namib at location called Gobabeb. Gobabeb dominated by basaltic minerals. Plagioclase, Fo56 olivine, two...
Abstract Vera Rubin ridge (VRR) is an erosion‐resistant feature on the northwestern slope of Mount Sharp in Gale crater, Mars, and orbital visible/shortwave infrared measurements indicate it contains red hematite. The Mars Science Laboratory Curiosity rover performed extensive campaign VRR to study its mineralogy, geochemistry, sedimentology determine depositional diagenetic history constrain processes by which hematite could have formed. X‐ray diffraction (XRD) data from CheMin instrument...
Crystal chemical algorithms were used to estimate the composition of selected mineral phases observed with CheMin X-ray diffractometer onboard NASA Curiosity rover in Gale crater, Mars. The sampled materials include two wind-blown soils, Rocknest and Gobabeb, six mudstones Yellowknife Bay formation (John Klein Cumberland) Murray (Confidence Hills, Mojave2, Telegraph Peak), as well five sandstones, Windjana samples unaltered Stimson (Big Sky Okoruso) altered (Greenhorn Lubango). major...
Abstract The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in active Bagnold dune field. are rounded subrounded, very fine medium sized (~45–500 μm) with ≥6 distinct grain colors. In contrast examined by a dust‐covered, inactive bedform called Rocknest soils at other landing sites, darker, less red, better sorted, have fewer silt‐sized or smaller grains, show no evidence for cohesion. Nevertheless,...
Modified clay minerals on Mars Sedimentary rocks exposed in Gale crater contain extensive minerals. Bristow et al. analyzed drill samples collected by the Curiosity rover as it climbed up sedimentary layers crater. They found evidence of past reactions with liquid water and sulfate brines, which could have percolated through from an overlying deposit. Similar deposits are widespread across planet represent some last to form before lost its surface water, so results inform our understanding...
Abstract The Glen Torridon (GT) region in Gale crater, Mars is a with strong clay mineral signatures inferred from orbital spectroscopy. CheMin X‐ray diffraction (XRD) instrument onboard the Science Laboratory rover, Curiosity , measured some of highest abundances to date within GT, complementing detections. GT may also be unique because XRD patterns samples, identified new phases, including: (a) Fe‐carbonates, and (b) phase novel peak at 9.2 Å. Fe‐carbonates have been previously suggested...
Abstract For the first time on Mars, crystalline magnesium‐sulfate mineral starkeyite (MgSO 4 ‧4H 2 O) was definitively identified using CheMin X‐ray diffraction instrument at Gale crater. At Canaima drill site, along with amorphous MgSO ‧ n H O are among “polyhydrated Mg‐sulfates” interpreted in orbital reflectance spectra. Mg‐sulfates good climate indicators as they very responsive to changes temperature and relative humidity. We hypothesize that, through evaporation, formed end of brine...
Ferrian saponite from the eastern Santa Monica Mountain, near Griffith Park (Los Angeles, California), was investigated as a mineralogical analog to smectites discovered on Mars by CheMin X-ray diffraction instrument onboard Science Laboratory (MSL) rover. The martian clay minerals occur in sediment of basaltic composition and have 02l bands peaking at 4.59 Å, consistent with tri-octahedral smectites. occurs basalts pseudomorphs after olivine mesostasis glass fillings vesicles cracks has...
Abstract Curiosity investigated active eolian sands near linear dunes during Phase 2 of the Bagnold Dunes campaign in Gale crater, Mars. Ogunquit Beach, a sample scooped from large‐ripple trough within Mount Desert Island ripple field and delivered to Chemistry Mineralogy (CheMin) X‐ray diffraction instrument, is dominated by basaltic igneous minerals amorphous materials. CheMin mineralogy Gobabeb acquired at crest on Namib barchan dune 1 similar Beach. however, contains more plagioclase...
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For more than a decade, the CheMin X-ray diffraction instrument on Mars Science Laboratory rover, Curiosity, has been returning definitive and quantitative mineralogical mineral–chemistry data from ~3.5-billion-year-old (Ga) sediments in Gale crater, Mars. To date, 40 drilled rock samples three scooped soil have analyzed during rover’s 30+ km transit. These document mineralogy of over 800 m flat-lying fluvial, lacustrine, aeolian sedimentary rocks that comprise lower strata central mound...
Abstract As part of the Bagnold Dune campaign conducted by Mars Science Laboratory rover Curiosity, visible/near‐infrared reflectance spectra dune sands were acquired using Mast Camera (Mastcam) multispectral imaging (445–1013 nm) and Chemistry (ChemCam) passive point spectroscopy (400–840 nm). By comparing from pristine rover‐disturbed ripple crests troughs within field, through analysis sieved grain size fractions, constraints on mineral segregation sorting could be determined. In general,...
Mathematical relationships between unit-cell parameters and chemical composition were developed for selected mineral phases observed with the CheMin X-ray diffractometer onboard Curiosity rover in Gale crater. This study presents algorithms estimating of based solely on diffraction data. The systems include plagioclase, alkali feldspar, Mg-Fe-Ca C2/c clinopyroxene, P21/c orthopyroxene, Mg-Fe olivine, magnetite, other spinel oxides, alunite-jarosite. These methods assume compositions Na-Ca...