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  • 1
    Publication Date: 2013-09-28
    Description: The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. The fraction of sand 〈150 micrometers in size contains ~55% crystalline material consistent with a basaltic heritage and ~45% x-ray amorphous material. The amorphous component of Rocknest is iron-rich and silicon-poor and is the host of the volatiles (water, oxygen, sulfur dioxide, carbon dioxide, and chlorine) detected by the Sample Analysis at Mars instrument and of the fine-grained nanophase oxide component first described from basaltic soils analyzed by MERs. The similarity between soils and aeolian materials analyzed at Gusev Crater, Meridiani Planum, and Gale Crater implies locally sourced, globally similar basaltic materials or globally and regionally sourced basaltic components deposited locally at all three locations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Blake, D F -- Morris, R V -- Kocurek, G -- Morrison, S M -- Downs, R T -- Bish, D -- Ming, D W -- Edgett, K S -- Rubin, D -- Goetz, W -- Madsen, M B -- Sullivan, R -- Gellert, R -- Campbell, I -- Treiman, A H -- McLennan, S M -- Yen, A S -- Grotzinger, J -- Vaniman, D T -- Chipera, S J -- Achilles, C N -- Rampe, E B -- Sumner, D -- Meslin, P-Y -- Maurice, S -- Forni, O -- Gasnault, O -- Fisk, M -- Schmidt, M -- Mahaffy, P -- Leshin, L A -- Glavin, D -- Steele, A -- Freissinet, C -- Navarro-Gonzalez, R -- Yingst, R A -- Kah, L C -- Bridges, N -- Lewis, K W -- Bristow, T F -- Farmer, J D -- Crisp, J A -- Stolper, E M -- Des Marais, D J -- Sarrazin, P -- MSL Science Team -- New York, N.Y. -- Science. 2013 Sep 27;341(6153):1239505. doi: 10.1126/science.1239505.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 94035, USA. david.blake@nasa.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24072928" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2013-12-11
    Description: H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO2. Concurrent evolution of O2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ming, D W -- Archer, P D Jr -- Glavin, D P -- Eigenbrode, J L -- Franz, H B -- Sutter, B -- Brunner, A E -- Stern, J C -- Freissinet, C -- McAdam, A C -- Mahaffy, P R -- Cabane, M -- Coll, P -- Campbell, J L -- Atreya, S K -- Niles, P B -- Bell, J F 3rd -- Bish, D L -- Brinckerhoff, W B -- Buch, A -- Conrad, P G -- Des Marais, D J -- Ehlmann, B L -- Fairen, A G -- Farley, K -- Flesch, G J -- Francois, P -- Gellert, R -- Grant, J A -- Grotzinger, J P -- Gupta, S -- Herkenhoff, K E -- Hurowitz, J A -- Leshin, L A -- Lewis, K W -- McLennan, S M -- Miller, K E -- Moersch, J -- Morris, R V -- Navarro-Gonzalez, R -- Pavlov, A A -- Perrett, G M -- Pradler, I -- Squyres, S W -- Summons, R E -- Steele, A -- Stolper, E M -- Sumner, D Y -- Szopa, C -- Teinturier, S -- Trainer, M G -- Treiman, A H -- Vaniman, D T -- Vasavada, A R -- Webster, C R -- Wray, J J -- Yingst, R A -- MSL Science Team -- New York, N.Y. -- Science. 2014 Jan 24;343(6169):1245267. doi: 10.1126/science.1245267. Epub 2013 Dec 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Astromaterials Research and Exploration Science Directorate, NASA Johnson Space Center, Houston, TX 77058, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24324276" target="_blank"〉PubMed〈/a〉
    Keywords: Bays ; Carbon Dioxide/analysis/chemistry ; *Exobiology ; Extraterrestrial Environment/*chemistry ; Geologic Sediments/analysis/chemistry ; Hydrocarbons, Chlorinated/*analysis ; *Mars ; Oxygen/analysis/chemistry ; Sulfides/analysis/chemistry ; Volatile Organic Compounds/*analysis ; Water/analysis/chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2013-12-11
    Description: 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, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vaniman, D T -- Bish, D L -- Ming, D W -- Bristow, T F -- Morris, R V -- Blake, D F -- Chipera, S J -- Morrison, S M -- Treiman, A H -- Rampe, E B -- Rice, M -- Achilles, C N -- Grotzinger, J P -- McLennan, S M -- Williams, J -- Bell, J F 3rd -- Newsom, H E -- Downs, R T -- Maurice, S -- Sarrazin, P -- Yen, A S -- Morookian, J M -- Farmer, J D -- Stack, K -- Milliken, R E -- Ehlmann, B L -- Sumner, D Y -- Berger, G -- Crisp, J A -- Hurowitz, J A -- Anderson, R -- Des Marais, D J -- Stolper, E M -- Edgett, K S -- Gupta, S -- Spanovich, N -- MSL Science Team -- New York, N.Y. -- Science. 2014 Jan 24;343(6169):1243480. doi: 10.1126/science.1243480. Epub 2013 Dec 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Planetary Science Institute, Tucson, AZ 85719, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24324271" target="_blank"〉PubMed〈/a〉
    Keywords: Extraterrestrial Environment/*chemistry ; Ferrosoferric Oxide/analysis/chemistry ; Geologic Sediments/analysis/*chemistry ; *Mars ; Minerals/analysis/*chemistry ; Silicates/analysis/chemistry ; Silicon Compounds/analysis/chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2013-12-11
    Description: 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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McLennan, S M -- Anderson, R B -- Bell, J F 3rd -- Bridges, J C -- Calef, F 3rd -- Campbell, J L -- Clark, B C -- Clegg, S -- Conrad, P -- Cousin, A -- Des Marais, D J -- Dromart, G -- Dyar, M D -- Edgar, L A -- Ehlmann, B L -- Fabre, C -- Forni, O -- Gasnault, O -- Gellert, R -- Gordon, S -- Grant, J A -- Grotzinger, J P -- Gupta, S -- Herkenhoff, K E -- Hurowitz, J A -- King, P L -- Le Mouelic, S -- Leshin, L A -- Leveille, R -- Lewis, K W -- Mangold, N -- Maurice, S -- Ming, D W -- Morris, R V -- Nachon, M -- Newsom, H E -- Ollila, A M -- Perrett, G M -- Rice, M S -- Schmidt, M E -- Schwenzer, S P -- Stack, K -- Stolper, E M -- Sumner, D Y -- Treiman, A H -- VanBommel, S -- Vaniman, D T -- Vasavada, A -- Wiens, R C -- Yingst, R A -- MSL Science Team -- New York, N.Y. -- Science. 2014 Jan 24;343(6169):1244734. doi: 10.1126/science.1244734. Epub 2013 Dec 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geosciences, State University of New York, Stony Brook, NY 11794, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24324274" target="_blank"〉PubMed〈/a〉
    Keywords: Bays ; Calcium Sulfate/analysis/chemistry ; Chlorine/analysis/chemistry ; *Exobiology ; Extraterrestrial Environment/*chemistry ; Ferrosoferric Oxide/analysis/chemistry ; Geologic Sediments/*chemistry ; Halogens/analysis/chemistry ; Hydrogen-Ion Concentration ; Iron/analysis/chemistry ; Magnesium/analysis/chemistry ; *Mars ; Silicates/analysis/chemistry ; Water/chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    ISSN: 1432-072X
    Keywords: Filamentous ; Phototrophic ; Purple bacteria ; Gliding motility ; Microcoleus chthonoplastes ; Ectothiorhodospira ; Hypersaline ; Cyanobacterial mat ; Microelectrodes ; Salt ponds ; Solar Lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8–0.9 μm wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300–1200 μm, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur bacteria is not available yet in pure culture, and its taxonomical position cannot be fully established. This organism is suggested to be a new type of gliding, filamentous, purple phototroph.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0066-4162
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract The search for the origins of life and its presence beyond Earth is strengthened by new technology and by evidence that life tolerates extreme conditions and that planets are widespread. Astrobiologists learn how planets develop and maintain habitable conditions. They combine biological and information sciences to decipher the origins of life. They examine how biota, particularly microorganisms, evolve, at scales from the molecular to the biosphere level, including interactions with long-term planetary changes. Astrobiologists learn how to recognize the morphological, chemical, and spectroscopic signatures of life in order to explore both extraterrestrial samples and electromagnetic spectra reflected from extrasolar planets.
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 2018-06-07
    Description: Clay minerals provide indicators of the evolution of aqueous conditions and possible habitats for life on ancient Mars. Analyses by the Mars Science Laboratory rover Curiosity show that ~3.5–billion year (Ga) fluvio-lacustrine mudstones in Gale crater contain up to ~28 weight % (wt %) clay minerals. We demonstrate that the species of clay minerals deduced from x-ray diffraction and evolved gas analysis show a strong paleoenvironmental dependency. While perennial lake mudstones are characterized by Fe-saponite, we find that stratigraphic intervals associated with episodic lake drying contain Al-rich, Fe 3+ -bearing dioctahedral smectite, with minor (3 wt %) quantities of ferripyrophyllite, interpreted as wind-blown detritus, found in candidate aeolian deposits. Our results suggest that dioctahedral smectite formed via near-surface chemical weathering driven by fluctuations in lake level and atmospheric infiltration, a process leading to the redistribution of nutrients and potentially influencing the cycling of gases that help regulate climate.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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