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Sample records for carbonaceous chondrite acfer

  1. A new CH carbonaceous chondrite from Acfer, Algeria

    OpenAIRE

    Moggi-Cecchi, V.; SALVADORI A; Pratesi, G; Franchi, Ian; Greenwood, Richard

    2006-01-01

    A single stone weighing 1456 g was found in November 2002 in the Acfer area, Algeria. Oxygen isotope, chondrules-matrix ratio as well as other petrographic features point to a classification as CH carbonaceous chondrite.

  2. Fluid Inclusions in Carbonaceous Chondrites

    Science.gov (United States)

    Saylor, J.; Zolensky, M. E.; Bodnar, R. J.; Le L.; Schwandt, C.

    2001-01-01

    Fluid inclusions are present in carbonaceous chondrites. Of the chondrites studied (CI1, CM1 and 2, CV3) fluid inclusions were found only in CM2s and CI1s, and by extrapolation are most likely to be found there in the future. Additional information is contained in the original extended abstract.

  3. Mossbauer Spectra of Weathered H5 Ordinary Chondrites from Reg EL Acfer, Algeria

    Science.gov (United States)

    Berry, F.; Oates, G.; Bland, P.; Pillinger, C. T.

    1992-07-01

    Approximately 380 meteorite specimens have been retrieved from the Acfer region of the Sahara desert, Algeria. To date, 26 of these have been classified H5 (Bischoff et al., 1990, 1991, 1992). Being the most common meteorite type and having a tightly constrained mineralogy (Mason, 1965), H5 chondrites are ideal candidates for investigating terrestrial weathering products in meteorites. Arid climate, uniform topography, and lack of a concentration/movement mechanism makes it likely that meteorites throughout Reg el Acfer were weathered by a common mechanism. Jull et al. (1991) showed a correlation in meteorites from Roosevelt County between terrestrial ^14C ages and a qualitative weathering scale. An aim of the present study is to provide a quantitative measure of weathering for the Acfer region that might allow an estimate of terrestrial age, as well as information on pairing. Meteorite Specimens: Approximately 1 g of sample was used, prepared by grinding under acetone to prevent oxidation during crushing, until a homogenized powder was produced. Mossbauer spectra were recorded at 298 degrees K with a microprocessor controlled Mossbauer spectrometer using a ^57Co/Rh source. Drive velocity was calibrated with the same source and a metallic iron foil. Results: The H5 chondrite Acfer 146 (Bischoff, forthcoming Meteoritical Bulletin) was found on 19/11/90 at coordinates 27 degrees 38'N, 4 degrees 05'E. This meteorite gave a spectrum dominated by quadrupole split absorption characteristics of Fe^2+ in a forsteritic olivine structure. A sample of the outer crust showed the additional presence of Fe^3+. XRD was insensitive to the unequivocal identification of the phases present in the two samples and given that the Mossbauer parameters of the hydrolyzed Fe^3+ species and ferric oxyhydroxides are very similar it is not possible at this stage to identify the oxidized phase. Clearly, however, the results demonstrate the sensitivity of Mossbauer spectroscopy to the products

  4. Carbonaceous chondrite clasts in the Kapoeta howardite

    Science.gov (United States)

    Brearley, Adrian J.; Papike, J. J.

    1993-01-01

    A petrographic and mineralogical study of a number of carbonaceous chondrite clasts in the Kapoeta howardite has been carried out. Most of the clasts have mineralogical and chemical properties which link them to the CM carbonaceous chondrites. Some clasts contain chondrules which often have well-developed fine-grained rims, but many have been extensively brecciated. PCP-rich objects are common and pentlandite and pyrrhotite also occur. Calcite has also been found. The remainder of the clasts are extremely fine-grained and appear to be closely related to CI carbonaceous chondrites. In these clasts magnetite framboids are common and finegrained sulfides and magnetite occur disseminated throughout the matrix.

  5. Extraterrestrial Nucleobases in Carbonaceous Chondrites

    Science.gov (United States)

    Martins, Z.; Botta, O.; Fogel, M.; Sephton, M.; Glavin, D.; Watson, J.; Dworkin, J.; Schwartz, A.; Ehrenfreund, P.

    Nucleobases in Carbonaceous Chondrites Z. Martins (1), O. Botta (2), M. L. Fogel (3), M. A. Sephton (4), D. P. Glavin (2), J. S. Watson (5), J. P. Dworkin (2), A. W. Schwartz (6) and P. Ehrenfreund (1,6). (1) Astrobiology Laboratory, Leiden Institute of Chemistry, Leiden, The Netherlands, (2) NASA Goddard Space Flight Center, Goddard Center for Astrobiology, Greenbelt, MD, USA, (3) GL, Carnegie Institution of Washington, Washington DC, USA, (4) Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, South Kensington Campus, Imperial College, London, UK, (5) Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes, UK, (6) Radboud University Nijmegen, Nijmegen, The Netherlands. E-mail: z.martins@chem.leidenuniv.nl/Phone:+31715274440 Nucleobases are crucial compounds in terrestrial biochemistry, because they are key components of DNA and RNA. Carbonaceous meteorites have been analyzed for nucleobases by different research groups [1-5]. However, significant quantitative and qualitative differences were observed, leading to the controversial about the origin of these nucleobases. In order to establish the origin of these compounds in carbonaceous chondrites and to assess the plausibility of their exogenous delivery to the early Earth, we have performed formic acid extraction of samples of the Murchison meteorite [6], followed by an extensive purification procedure, analysis and quantification by high-performance liquid chromatography with UV absorption detection and gas chromatography-mass spectrometry. Our results were qualitatively consistent with previous results [3, 4], but showed significant quantitative differences. Compound specific carbon isotope values were obtained, using gas chromatography-combustion- isotope ratio mass spectrometry. A soil sample collected in the proximity of the Murchison meteorite fall site was subjected to the same extraction, purification and analysis procedure

  6. Magnetic evidence for a partially differentiated carbonaceous chondrite parent body

    OpenAIRE

    Carporzen, Laurent; Weiss, Benjamin P.; Elkins-Tanton, Linda T.; Shuster, David L.; Ebel, Denton; Gattacceca, Jérôme

    2011-01-01

    The textures of chondritic meteorites demonstrate that they are not the products of planetary melting processes. This has long been interpreted as evidence that chondrite parent bodies never experienced large-scale melting. As a result, the paleomagnetism of the CV carbonaceous chondrite Allende, most of which was acquired after accretion of the parent body, has been a long-standing mystery. The possibility of a core dynamo like that known for achondrite parent bodies has been discounted beca...

  7. Presolar diamond, silicon carbide, and graphite in carbonaceous chondrites: implications for thermal processing in the solar nebula

    Science.gov (United States)

    Huss, Gary R.; Meshik, Alex P.; Smith, Julie B.; Hohenberg, C. M.

    2003-12-01

    We have determined abundances of presolar diamond, silicon carbide, graphite, and Xe-P1 (Q-Xe) in eight carbonaceous chondrites by measuring the abundances of noble gas tracers in acid residues. The meteorites studied were Murchison (CM2), Murray (CM2), Renazzo (CR2), ALHA77307 (CO3.0), Colony (CO3.0), Mokoia (CV3 ox), Axtell (CV3 ox), and Acfer 214 (CH). These data and data obtained previously by Huss and Lewis (1995) provide the first reasonably comprehensive database of presolar-grain abundances in carbonaceous chondrites. Evidence is presented for a currently unrecognized Ne-E(H) carrier in CI and CM2 chondrites. After accounting for parent-body metamorphism, abundances and characteristics of presolar components still show large variations across the classes of carbonaceous chondrites. These variations correlate with the bulk compositions of the host meteorites and imply that the same thermal processing that was responsible for generating the compositional differences between the various chondrite groups also modified the initial presolar-grain assemblages. The CI chondrites and CM2 matrix have the least fractionated bulk compositions relative to the sun and the highest abundances of most types of presolar material, particularly the most fragile types, and thus are probably most representative of the material inherited from the sun's parent molecular cloud. The other classes can be understood as the products of various degrees of heating of bulk molecular cloud material in the solar nebula, removing the volatile elements and destroying the most fragile presolar components, followed by chondrule formation, metal-silicate fractionation in some cases, further nebula processing in some cases, accretion, and parent body processing. If the bulk compositions and the characteristics of the presolar-grain assemblages in various chondrite classes reflect the same processes, as seems likely, then differential condensation from a nebula of solar composition is ruled out as

  8. Petrology of Amoeboid Olivine Aggregates in Antarctic CR Chondrites: Comparison With Other Carbonaceous Chondrites

    Science.gov (United States)

    Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Zolensky, M. E.; Yasutake, M.

    2016-01-01

    Amoeboid olivine aggregates (AOAs) are important refractory components of carbonaceous chondrites and have been interpreted to represent solar nebular condensates that experienced high-temperature annealing, but largely escaped melting. In addition, because AOAs in primitive chondrites are composed of fine-grained minerals (forsterite, anorthite, spinel) that are easily modified during post crystallization alteration, the mineralogy of AOAs can be used as a sensitive indicator of metamorphic or alteration processes. AOAs in CR chondrites are particularly important because they show little evidence for secondary alteration. In addition, some CR AOAs contain Mn-enriched forsterite (aka low-iron, Mn-enriched or LIME olivine), which is an indicator of nebular formation conditions. Here we report preliminary results of the mineralogy and petrology of AOAs in Antarctic CR chondrites, and compare them to those in other carbonaceous chondrites.

  9. Origin of Thorium/Uranium Variations in Carbonaceous Chondrites

    OpenAIRE

    Goreva, J. S.; Burnett, D. S.

    2000-01-01

    Thorium-, U-, and Pb-isotopic analyses of a wide variety of planetary materials show that Th/U ratio (by weight) varies from 3.5 to 4.2. It is generally believed that chondritic meteorites contain refractory lithophile elements in a relative proportions close to solar, i.e., CI chondrites [1]. Surprisingly, a number of analyses of different types of carbonaceous chondrites show a large (at least a factor of 3) scatter in Th/U measurements [2]. The widest spread in Th/U is observed in the most...

  10. Correlated alteration effects in CM carbonaceous chondrites

    Science.gov (United States)

    Browning, Lauren B.; McSween, Harry Y., Jr.; Zolensky, Michael E.

    1996-07-01

    Three parameters are proposed to determine the relative extent of alteration in CM chondrites. The mineralogic alteration index monitors the relative progress of coupled substitutions in the progressive alteration of cronstedtite to Mg-serpentine and increases with increasing alteration. To calculate values of this index, an algorithm has been developed to estimate the average matrix phyllosilicate composition in individual CM chondrites. The second parameter is the volume percent of isolated matrix silicates, which decreases with progressive alteration due to mineral hydration. Finally, the volume percent of chondrule alteration monitors the extent of chondrule phyllosilicate production and increases as alteration proceeds. These parameters define the first CM alteration scale that relies on multiple indicators of progressive alteration. The following relative order of increasing alteration is established by this model: Murchison ≤ Bells Cochabamba and Boriskino experienced is less precisely constrained, although both fall near the middle of this sequence. A comparison between the mineralogic alteration index and literature values for the whole-rock chemistry of CM chondrites reveals several correlations. A positive, nearly linear correlation between bulk H content and progressive CM alteration suggests an approximately constant production rate of new phyllosilicates relative to the mineralogical transition from cronstedtite to Mg-serpentine. The abundance of trapped planetary 36Ar decreases systematically in progressively altered CM chondrites, suggesting the wholesale destruction of primary noble gas carrier phase (s) by aqueous reactions. Because low temperature fluid-rock reactions are generally associated with large isotopic mass fractionation factors, we also compared our model predictions with δ18O values for bulk CM samples. Although some of these data are poorly resolved, the order of increasing δ18O values approximates the order of increasing

  11. R Raman Spectroscopy and Petrology of Antarctic CR Chondrites: Comparison with Other Carbonaceous Chondrites

    Science.gov (United States)

    Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Zolensky, M. E.; Yasutake, M.

    2015-01-01

    In Renazzo-like carbonaceous (CR) chondrites, abundant original Fe,Ni-metal is preserved in chrondules, but the matrix is characterized by fine-grained magnetite with phyllosilicate. This combination of reduced Fe in chrodrules with oxidized Fe and phyllosilicate in the matrix has been attributed to aqueous alteration of matrix at relatively low temperatures.

  12. Magnetic evidence for a partially differentiated carbonaceous chondrite parent body

    Science.gov (United States)

    Carporzen, Laurent; Weiss, Benjamin P.; Elkins-Tanton, Linda T.; Shuster, David L.; Ebel, Denton; Gattacceca, Jérôme

    2011-01-01

    The textures of chondritic meteorites demonstrate that they are not the products of planetary melting processes. This has long been interpreted as evidence that chondrite parent bodies never experienced large-scale melting. As a result, the paleomagnetism of the CV carbonaceous chondrite Allende, most of which was acquired after accretion of the parent body, has been a long-standing mystery. The possibility of a core dynamo like that known for achondrite parent bodies has been discounted because chondrite parent bodies are assumed to be undifferentiated. Resolution of this conundrum requires a determination of the age and timescale over which Allende acquired its magnetization. Here, we report that Allende’s magnetization was acquired over several million years (Ma) during metasomatism on the parent planetesimal in a >  ∼ 20 μT field up to approximately 9—10 Ma after solar system formation. This field was present too recently and directionally stable for too long to have been generated by the protoplanetary disk or young Sun. The field intensity is in the range expected for planetesimal core dynamos, suggesting that CV chondrites are derived from the outer, unmelted layer of a partially differentiated body with a convecting metallic core.

  13. Aqueous Alteration Mineralogy in CM Carbonaceous Chondrites

    Science.gov (United States)

    Chokai, J.; Zolensky, M.; Le, L.; Nakamura, K.; Mikouchi, T.; Monkawa, A.; Koizumi, E.; Miyamoto, M.

    2004-01-01

    Iron-nickel sulfides are found in most or all solar system environments, and are probably the only minerals found in all extraterrestrial materials on hand. Despite the ubiquity, they have not received the attention they deserve. The most common Fe-Ni sulfides in chondrites are troilite (FeS), pyrrhotite (Fe1- XS) and pentlandite (Fe,Ni)9S8. Troilite is believed to have resulted from sulfidation of metal (Fe-Ni) grains in an H2Scontaining environment. Pyrrhotite is produced when friable troilite grains, which are exfoliated from the metal nucleus, are submitted to continued sulfidation [1]. Some asteroids are known to have experienced aqueous alteration, forming products including new generations of sulfides (pyrrhotite and pentlandite). Pentlandite in particular is known to form during such alteration [1]. However, experimental work by Lauretta has indicated that pentlandite may also have been formed during the initial sulfidation process [2], due to the faster diffusion rate of nickel into the forming sulfide, as compared to iron. Finally, there is considerable evidence [1,3&4] for a family of phases intermediate between pyrrhotite and pentlandite, following the trend of the high temperature monosulfide solid solution [5], something not encountered in terrestrial rocks.

  14. Comparing Amino Acid Abundances and Distributions Across Carbonaceous Chondrite Groups

    Science.gov (United States)

    Burton, Aaron S.; Callahan, Michael P.; Glavin, Daniel P.; Elsila, Jamie E.; Dworkin, Jason P.

    2012-01-01

    Meteorites are grouped according to bulk properties such as chemical composition and mineralogy. These parameters can vary significantly among the different carbonaceous chondrite groups (CI, CM, CO, CR, CH, CB, CV and CK). We have determined the amino acid abundances of more than 30 primary amino acids in meteorites from each of the eight groups, revealing several interesting trends. There are noticeable differences in the structural diversity and overall abundances of amino acids between meteorites from the different chondrite groups. Because meteorites may have been an important source of amino acids to the prebiotic Earth and these organic compounds are essential for life as we know it, the observed variations of these molecules may have been important for the origins of life.

  15. Petrogenesis of opaque assemblages in the Ningqiang carbonaceous chondrite

    Institute of Scientific and Technical Information of China (English)

    HSU; WeiBiao

    2007-01-01

    Numerous round to oblate opaque assemblages (OAs) are found in chondrules and matrix of the Ningqiang carbonaceous chondrite. They are mainly composed of Ni-rich metal,magnetite,Fe,Ni-sulfides,with minor amounts of phosphate,phosphoran-olivine,pyroxene and trace amounts of nano-sized platinum-group metal alloys. The mineralogy of Ningqiang OAs is very similar to that of OAs previously reported in Ca,Al-rich inclusions of CV chondrites. Being a rare mineral phase in nature,phosphoran-olivine is thought to form by nonequilibrium reactions between P-bearing molten metal and olivine crystals during rapid cooling. Its occurrence in Ningqiang OAs indicates that the precursor of OAs was locally produced during chondrule formation,rather than directly condensed from the solar nebula as previously thought. The petrographic and mineralogical characteristics of Ningqiang OAs reveal that OAs formed by low temperature alterations of pre-existing homogeneous alloys within chondrules on a planetary body.

  16. Organic matter in carbonaceous chondrites, planetary satellites, asteroids and comets

    Science.gov (United States)

    Cronin, John R.; Pizzarello, Sandra; Cruikshank, Dale P.

    1988-01-01

    A detailed review is given of the organic compounds found in carbonaceous chondrite meteorites, especially the Murchison meteorite, and detected spectroscopically in other solar-system objects. The chemical processes by which the organic compounds could have formed in the early solar system and the conditions required for these processes are discussed, taking into account the possible alteration of the compounds during the lifetime of the meteoroid. Also considered are the implications for prebiotic evolution and the origin of life. Diagrams, graphs, and tables of numerical data are provided.

  17. New phyllosilicate types in a carbonaceous chondrite matrix

    Science.gov (United States)

    Mackinnon, I. D. R.; Buseck, P. R.

    1979-01-01

    Observations of new types of layer silicates in the crystalline regions of the matrix of a carbonaceous chondrite are reported. Ion-thinned sections of the Murchison meteorite were observed by high-resolution transmission electron microscopy. Images obtained of patterns of fringe spacings of 4.9 and 7.3 A are interpreted as resulting from ordered and disordered sequences of brucite-like and serpentine-like layers, respectively. The temperature and pressure conditions of phyllosilicate formation in the Murchison matrix are discussed in light of the suggested crysotile serpentine and brucite layers and evidence of Fe and Al in the layered intergrowths.

  18. Delivery of Dark Material to Vesta via Carbonaceous Chondritic Impacts

    CERN Document Server

    Reddy, Vishnu; O'Brien, David P; Nathues, Andreas; Cloutis, Edward A; Durda, Daniel D; Bottke, William F; Bhatt, Megha U; Nesvorny, David; Buczkowski, Debra; Scully, Jennifer E C; Palmer, Elizabeth M; Sierks, Holger; Mann, Paul J; Becker, Kris J; Beck, Andrew W; Mittlefehldt, David; Li, Jian-Yang; Gaskell, Robert; Russell, Christopher T; Gaffey, Michael J; McSween, Harry Y; McCord, Thomas B; Combe, Jean-Philippe; Blewett, David

    2012-01-01

    NASA's Dawn spacecraft observations of asteroid (4) Vesta reveal a surface with the highest albedo and color variation of any asteroid we have observed so far. Terrains rich in low albedo dark material (DM) have been identified using Dawn Framing Camera (FC) 0.75 {\\mu}m filter images in several geologic settings: associated with impact craters (in the ejecta blanket material and/or on the crater walls and rims); as flow-like deposits or rays commonly associated with topographic highs; and as dark spots (likely secondary impacts) nearby impact craters. This DM could be a relic of ancient volcanic activity or exogenic in origin. We report that the majority of the spectra of DM are similar to carbonaceous chondrite meteorites mixed with materials indigenous to Vesta. Using high-resolution seven color images we compared DM color properties (albedo, band depth) with laboratory measurements of possible analog materials. Band depth and albedo of DM are identical to those of carbonaceous chondrite xenolith-rich howar...

  19. Young Pb-Isotopic Ages of Chondrules in CB Carbonaceous Chondrites

    Science.gov (United States)

    Amelin, Yuri; Krot, Alexander N.

    2005-01-01

    CB (Bencubbin-type) carbonaceous chondrites differ in many ways from more familiar CV and CO carbonaceous chondrites and from ordinary chondrites. CB chondrites are very rich in Fe-Ni metal (50-70 vol%) and contain magnesian silicates mainly as angular to sub-rounded clasts (or chondrules) with barred olivine (BO) or cryptocrystalline (CC) textures. Both metal and silicates appear to have formed by condensation. The sizes of silicate clasts vary greatly between the two subgroups of CB chondrites: large (up to one cm) in CB(sub a) chondrites, and typically to much much less than 1 mm in CB(sub b) chondrites. The compositional and mineralogical differences between these subgroups and between the CB(sub s) and other types of chondrites suggest different environment and possibly different timing of chondrule formation. In order to constrain the timing of chondrule forming processes in CB(sub s) and understand genetic relationship between their subgroups, we have determined Pb-isotopic ages of silicate material from the CB(sub a) chondrite Gujba and CB(sub b) chondrite Hammadah al Hamra 237 (HH237 hereafter).

  20. Petrologic study of the Belgica 7904 carbonaceous chondrite - Hydrous alteration, oxygen isotopes, and relationship to CM and CI chondrites

    Science.gov (United States)

    Ikeda, Y.; Prinz, M.

    1993-01-01

    The genetic relationships between the petrology, hydration reactions, and isotopic oxygen composition in the Belgica 7904 (B7904) carbonaceous chondrite, and the relationship between B7904 and the CM and CI chondrites were investigated by characterizing seven components separated from B7904. The seven specimens included two partially altered chondrules, two phylosilicate clasts, two olivine fragments, and one matrix sample. The results of the analyses and thermodynamic calculations suggest that CI chondrites may have been produced in a two-stage alteration process from materials similar to that of the B7904 matrix, by reactions with liquid water in their parent body. The common CM chondrites may have undergone aqueous alteration in the parent body, in addition to hydration in the nebula, resulting in two-stage alterations; the parent body may have been different from that of B7904.

  1. Bulk Chemical Composition of the Ningqiang Carbonaceous Chondrite:An Issue of Classification

    Institute of Scientific and Technical Information of China (English)

    WANG Guiqin; LIN Yangting

    2007-01-01

    The Ningqiang meteorite is a fall carbonaceous chondrite, containing various Ca-, Al-rich inclusions that usually escaped from secondary events such as high-temperature heating and lowtemperature alteration. However, it has not yet been classified into any known chemical group. In order to address this issue, 41 elements of the bulk Ningqiang meteorite were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atom emission spectrometry (ICP-AES) in this study. The Allende (CV3) carbonaceous chondrite and the Jilin (H5)ordinary chondrite were also measured as references, and our analyses are consistent with the previous results. Rare earth and other refractory lithophile elements are depleted in Ningqiang relative to both Allende and mean CK chondrites. In addition, the REE pattern of Ningqiang is nearly flat, while that of Allende shows slight enrichment of LREE relative to HREE. Siderophile elements of Ningqiang are close to those of mean CK chondrites, but lower than those of Allende. Our new analyses indicate that Ningqiang cannot be classified into any known group of carbonaceous chondrites, consistent with previous reports.

  2. Petrologic Locations of Nanodiamonds in Carbonaceous Chondrite Meteorites

    Science.gov (United States)

    Garvie, Laurence

    Nanodiamonds (NDs), with dimensions near two nanometers, are widespread accessory minerals in primitive meteorites. They have been studied extensively in concentrates made from acid-insoluble residues, but surprisingly little is known about their petrologic settings in the meteorites because they have not been studied in situ. Information about such settings is fundamental for determining how they formed and were incorporated into the meteorites. The primary goal of the planned research is to determine and compare the petrologic settings of NDs within matrix of different types of carbonaceous chondrites, with the long-term aim of providing new insights regarding the origin of NDs. This research will also provide new data on the structure and major and trace element compositions of individual NDs and regions within them. Transmission electron microscopes (TEMs) provide uniquely powerful information regarding chemical, bonding, and structural data on the scale needed to solve this problem, assuming the NDs can be located within the host matrix. We have developed methods of observing NDs in situ within the fine-grained matrix of primitive meteorites and will use various TEMs to accomplish that goal for several meteorites. High- resolution imaging and electron energy-loss spectroscopy (EELS) will permit determination of both structural and chemical information about the NDs and their adjacent minerals. By the middle of the proposed grant period, two state-of-the-art, aberration-corrected TEMs will have been installed at ASU and will be used to locate heavy elements such as Xe, Te, and Pd within the NDs. These TEMs permit the imaging of individual atoms of heavy elements with annular dark-field (ADF) imaging, and these atoms can be identified using EELS. The result of these new types of measurements will provide information about whether such elements, which have been used to determine whether NDs formed in supernovae, occur within the interiors or on the surfaces of

  3. Extraterrestrial Amino Acids Identified in Metal-Rich CH and CB Carbonaceous Chondrites from Antarctica

    Science.gov (United States)

    Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

    2013-01-01

    Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondritesbut are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment(PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675(CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratiomass spectrometry. The (delta D, delta C-13, delta N-15) ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (1316 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.22 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of beta-, gamma-, and delta-amino acids compared to the corresponding alpha-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

  4. Proto-Planetary Disk Chemistry Recorded by D-Rich Organic Radicals in Carbonaceous Chondrites

    OpenAIRE

    Remusat, Laurent; Robert, François; Meibom, Anders; Mostefaoui, Smail; Delpoux, Olivier; Binet, Laurent; Gourier, Didier; Derenne, Sylvie

    2009-01-01

    Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed ~4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that orga...

  5. What Are Space Exposure Histories Telling Us about CM Carbonaceous Chondrites?

    Science.gov (United States)

    Takenouchi, A.; Zolensky, Michael E.; Nishiizumi, K.; Caffee, M.; Velbel, M. A.; Ross, K.; Zolensky, P.; Le, L.; Imae, N.; Yamaguchi, A.; Mikouchi, T.

    2013-01-01

    Chondrites are chemically primitive and carbonaceous (C) chondrites are potentially the most primitive among them because they mostly escaped thermal metamor-phism that affected the other chondrite groups and ratios of their major, non-volatile and most of the volatile elements are similar to those of the Sun. Therefore, C chondrites are ex-pected to retain a good record of the origin and early history of the solar system. Carbonaceous chondrites are chemically differentiated from other chondrites by their high Mg/Si ratios and refractory elements, and have experienced various degrees of aqueous alteration. They are subdivided into eight subgroups (CI, CM, CO, CV, CK, CR, CB and CH) based on major element and oxygen isotopic ratios. Their elemental ratios spread over a wide range though those of ordinary and enstatite chondrites are relatively uniform. It is critical to know how many sepa-rate bodies are represented by the C chondrites. In this study, CM chondrites, the most abundant carbona-ceous chondrites, are examined. They are water-rich, chon-drule- and CAI-bearing meteorites and most of them are brec-cias. High-temperature components such as chondrules, iso-lated olivine and CAIs in CMs are frequently altered and some of them are replaced by clay minerals and surrounded by sul-fides whose Fe was derived from mafic silicates. On the basis of degrees of aqueous alteration, CMs have been classified into subtypes from 1 to 2, although Rubin et al. [1] assigned subtype 1 to subtype 2 and subtype 2 to subtype 2.6 using various petrologic properties. The classification is based on petrographic and mineralogic properties. For example, though tochilinite (2[(Fe, Mg, Cu, Ni[])S] 1.57-1.85 [(Mg, Fe, Ni, Al, Ca)(HH)2]) clumps are produced during aqueous alteration, they disappear and sulfide appears with increasing degrees of aqueous alteration. Cosmic-ray exposure (CRE) age measurements of CM chondrites reveal an unusual feature. Though CRE ages of other chondrite

  6. Aliphatic amines in Antarctic CR2, CM2, and CM1/2 carbonaceous chondrites

    Science.gov (United States)

    Aponte, José C.; McLain, Hannah L.; Dworkin, Jason P.; Elsila, Jamie E.

    2016-09-01

    Meteoritic water-soluble organic compounds provide a unique record of the processes that occurred during the formation of the solar system and the chemistry preceding the origins of life on Earth. We have investigated the molecular distribution, compound-specific δ13C isotopic ratios and enantiomeric compositions of aliphatic monoamines present in the hot acid-water extracts of the carbonaceous chondrites LAP 02342 (CR2), GRA 95229 (CR2), LON 94101 (CM2), LEW 90500 (CM2), and ALH 83100 (CM1/2). Analyses of the concentration of monoamines in these meteorites revealed: (a) the CR2 chondrites studied here contain higher concentrations of monoamines relative to the analyzed CM2 chondrites; (b) the concentration of monoamines decreases with increasing carbon number; and (c) isopropylamine is the most abundant monoamine in these CR2 chondrites, while methylamine is the most abundant amine species in these CM2 and CM1/2 chondrites. The δ13C values of monoamines in CR2 chondrite do not correlate with the number of carbon atoms; however, in CM2 and CM1/2 chondrites, the 13C enrichment decreases with increasing monoamine carbon number. The δ13C values of methylamine in CR2 chondrites ranged from -1 to +10‰, while in CM2 and CM1/2 chondrites the δ13C values of methylamine ranged from +41 to +59‰. We also observed racemic compositions of sec-butylamine, 3-methyl-2-butylamine, and sec-pentylamine in the studied carbonaceous chondrites. Additionally, we compared the abundance and δ13C isotopic composition of monoamines to those of their structurally related amino acids. We found that monoamines are less abundant than amino acids in CR2 chondrites, with the opposite being true in CM2 and CM1/2 chondrites. We used these collective data to evaluate different primordial synthetic pathways for monoamines in carbonaceous chondrites and to understand the potential common origins these molecules may share with meteoritic amino acids.

  7. Hydrothermal preparation of analogous matrix minerals of CM carbonaceous chondrites from metal alloy particles

    Science.gov (United States)

    Peng, Yiya; Jing, Yunhai

    2014-12-01

    A mineral assemblage that is analogous to the matrix minerals of CM carbonaceous chondrites was produced from an alloyed metal particle mixture of Fe, Mg, Al, Si, and Ni in reducing, basic and S2-containing hydrothermal environments. The elemental ratios of the alloyed metal particle mixture were adopted from reported matrix composition of the carbonaceous chondrite Murchison. The characteristic minerals of the synthetic mineral assemblage are cronstedtite, tochilinite and tochilinite-cronstedtite-intergrowth, other minerals include polyhedral serpentine, chrysotile-like phase, nanotube-like hollow structures, lizardite-like phase, brucite-like phase, etc. (not every mineral appears in a single sample, however, cronstedtite and tochilinite are two invariant minerals in the synthetic mineral assemblage). The dominant individual minerals in the synthetic mineral assemblage have remarkable similarity to the corresponding minerals of the matrix of CM carbonaceous chondrites in composition, morphology, structure, and crystallinity. Our experimental work indicates that matrix minerals of CM carbonaceous chondrites formed billions of years ago may be reproduced under laboratory conditions.

  8. Early aqueous activity on the ordinary and carbonaceous chondrite parent bodies recorded by fayalite.

    Science.gov (United States)

    Doyle, Patricia M; Jogo, Kaori; Nagashima, Kazuhide; Krot, Alexander N; Wakita, Shigeru; Ciesla, Fred J; Hutcheon, Ian D

    2015-01-01

    Chronology of aqueous activity on chondrite parent bodies constrains their accretion times and thermal histories. Radiometric (53)Mn-(53)Cr dating has been successfully applied to aqueously formed carbonates in CM carbonaceous chondrites. Owing to the absence of carbonates in ordinary (H, L and LL), and CV and CO carbonaceous chondrites, and the lack of proper standards, there are no reliable ages of aqueous activity on their parent bodies. Here we report the first (53)Mn-(53)Cr ages of aqueously formed fayalite in the L3 chondrite Elephant Moraine 90161 as Myr after calcium-aluminium-rich inclusions (CAIs), the oldest Solar System solids. In addition, measurements using our synthesized fayalite standard show that fayalite in the CV3 chondrite Asuka 881317 and CO3-like chondrite MacAlpine Hills 88107 formed and Myr after CAIs, respectively. Thermal modelling, combined with the inferred conditions (temperature and water/rock ratio) and (53)Mn-(53)Cr ages of aqueous alteration, suggests accretion of the L, CV and CO parent bodies ∼1.8-2.5 Myr after CAIs. PMID:26100451

  9. Ion irradiation of carbonaceous chondrites as a simulation of space weathering on C-complex asteroids

    Science.gov (United States)

    Lantz, C.; Brunetto, R.; Barucci, M. A.; Bachelet, C.; Baklouti, D.; Bourçois, J.; Dartois, E.; Duprat, J.; Duret, P.; Engrand, C.; Godard, M.; Ledu, D.; Mivumbi, O.; Fornasier, S.

    2015-10-01

    We are investigating the effects of space weathering on primitive asteroids using ion irradiation on their meteoritic analogs. To do so, we exposed several carbonaceous chondrites (CV Allende, COs Lancé and Frontier Mountain 95002, CM Mighei, CI Alais, and ungrouped Tagish Lake) to 40 keV He+ ions as a simulation of solar wind irradiation using fluences up to 6.1016 ions/cm2 (implantation platform IRMA at CSNSM Orsay). As a test for our new experimental setup, we also studied samples of olivine and diopside. We confirm the reddening and darkening trends on S-type objects, but carbonaceous chondrites present a continuum of behaviors after ion irradiation as a function of the initial albedo and carbon content: from red to blue and from dark to bright.

  10. Proposed structures for poorly characterized phases in C2M carbonaceous chondrite meteorites

    Science.gov (United States)

    Mackinnon, I. D. R.; Zolensky, M. E.

    1984-01-01

    A recent investigation of C2M carbonaceous chondrite meteorite matrices using electron microscopy and High-Resolution Transmission Electron Microscopy (HRTEM) has provided data on the structure and chemistry of Poorly Characterized Phases (PCP). It is suggested that a dominant matrix variety (10 A PCP) has a structure equivalent to iron-rich tochinilite (6Fe0.9S5/Fe, Mg//OHO2/), which consists of coherently intrastratified mackinawite and brucite sheets. In addition, it is proposed that 17 A PCP is a commensurate intergrowth of serpentine and tochinilite layers. Various forms of PCP observed in carbonaceous chondrites appear to be intergrowths of tochinilite, serpentine, and tochinilite-serpentine minerals.

  11. In Situ Mapping of the Organic Matter in Carbonaceous Chondrites and Mineral Relationships

    Science.gov (United States)

    Clemett, Simon J.; Messenger, S.; Thomas-Keprta, K. L.; Ross, D. K.

    2012-01-01

    Carbonaceous chondrite organic matter represents a fossil record of reactions that occurred in a range of physically, spatially and temporally distinct environments, from the interstellar medium to asteroid parent bodies. While bulk chemical analysis has provided a detailed view of the nature and diversity of this organic matter, almost nothing is known about its spatial distribution and mineralogical relationships. Such information is nevertheless critical to deciphering its formation processes and evolutionary history.

  12. Titanium-rich oxide-bearing plagioclase-olivine inclusions in the unusual Ningqiang carbonaceous chondrite

    OpenAIRE

    Lin,Yangting /Kimura,Makoto

    1997-01-01

    Two plagioclase-olivine inclusions (POIs) from the unusual Ningqiang carbonaceous chondrite were studied to understand their mineralogy and crystallization history. In addition to the major phases plagioclase, spinel, olivine and pyroxene, Ningqiang POIs are characterized by interstitial assemblages composed of Ca-rich and Ca-poor pyroxenes, Ti-rich oxides and the other phases. The Ti-rich oxides include an unidentified titanium mineral series referred to as phase T, Ca-rich and Mg, Fe-rich a...

  13. The Spatial Distribution of Organic Matter and Mineralogical Relationships in Carbonaceous Chondrites

    Science.gov (United States)

    Clemett, S. J.; Messenger, S.; Thomas-Keprta, K. L.; Nakamura-Messenger, K.

    2012-01-01

    Organic matter present within primitive carbonaceous meteorites represents the complex conglomeration of species formed in a variety of physically and temporally distinct environments including circumstellar space, the interstellar medium, the Solar Nebula & Jovian sub-nebulae and asteroids. In each case, multiple chemical pathways would have been available for the synthesis of organic molecules. Consequently these meteorites constitute a unique record of organic chemical evolution in the Universe and one of the biggest challenges in organic cosmochemistry has been in deciphering this record. While bulk chemical analysis has provided a detailed description of the range and diversity of organic species present in carbonaceous chondrites, there is virtually no hard experimental data as to how these species are spatially distributed and their relationship to the host mineral matrix, (with one exception). The distribution of organic phases is nevertheless critical to understanding parent body processes. The CM and CI chondrites all display evidence of low temperature (organics and synthesis of new organics coupled to aqueous mineral alteration. To address such issues we have applied the technique of microprobe two-step laser desorption / photoionization mass spectrometry (L2MS) to map in situ the spatial distribution of a broad range of organic species at the micron scale in the freshly exposed matrices of the Bells, Tagish Lake and Murchison (CM2) carbonaceous chondrites.

  14. Spectral parameters for Dawn FC color data: Carbonaceous chondrites and aqueous alteration products as potential cerean analog materials

    Science.gov (United States)

    Schäfer, Tanja; Nathues, Andreas; Mengel, Kurt; Izawa, Matthew R. M.; Cloutis, Edward A.; Schäfer, Michael; Hoffmann, Martin

    2016-02-01

    We identified a set of spectral parameters based on Dawn Framing Camera (FC) bandpasses, covering the wavelength range 0.4-1.0 μm, for mineralogical mapping of potential chondritic material and aqueous alteration products on dwarf planet Ceres. Our parameters are inferred from laboratory spectra of well-described and clearly classified carbonaceous chondrites representative for a dark component. We additionally investigated the FC signatures of candidate bright materials including carbonates, sulfates and hydroxide (brucite), which can possibly be exposed on the cerean surface by impact craters or plume activity. Several materials mineralogically related to carbonaceous chondrites, including pure ferromagnesian phyllosilicates, and serpentinites were also investigated. We tested the potential of the derived FC parameters for distinguishing between different carbonaceous chondritic materials, and between other plausible cerean surface materials. We found that the major carbonaceous chondrite groups (CM, CO, CV, CK, and CR) are distinguishable using the FC filter ratios 0.56/0.44 μm and 0.83/0.97 μm. The absorption bands of Fe-bearing phyllosilicates at 0.7 and 0.9 μm in terrestrial samples and CM carbonaceous chondrites can be detected by a combination of FC band parameters using the filters at 0.65, 0.75, 0.83, 0.92 and 0.97 μm. This set of parameters serves as a basis to identify and distinguish different lithologies on the cerean surface by FC multispectral data.

  15. Checking Contamination during Storage of Carbonaceous Chondrites for Micro FTIR Measurements

    Science.gov (United States)

    Zolensky, Michael E.

    2008-01-01

    We examined organic contamination by Fourier transform infrared micro spectroscopic (micro FTIR) measurements of carbonaceous chondrite samples. Carbonaceous chondrites, Tagish Lake (C2), Murchison (CM2) and Moss (CO3), and some mineral powder samples pressed on aluminum plates were measured by micro FTIR before and after storage in several containers with silicone rubber mat. During storage, samples did not touch directly anything except the holding aluminum plates. The carbonaceous chondrites containing hydrous minerals (Tagish Lake and Murchison) pressed on aluminum plates and measured by transmission-reflection micro FTIR measurements were found to be contaminated during storage after only one day, as revealed by an increase of approximately 2965 /cm and approximately 1260 /cm peaks. The Moss meteorite which contains no hydrous minerals, did not show an increase of these peaks, indicating no organic contamination. This difference is probably related to the differing mineralogy and physical properties (including porosity and permeability) of these chondrites. Hydrous minerals such as antigorite, muscovite, montmorillonite and silica gel showed organic contamination by the same infrared measurements, while anhydrous materials such as SiO2 and KBr showed no contamination. These results indicate importance of surface OH groups for the organic contamination. Organic contamination was found on silica gel samples pressed on aluminum plates when they were stored within containers including silicone rubber, silicone grease or adhesive tape. Long path gas cell FTIR measurements for silicone rubber indicated methylsiloxane oligomers were released from the silicone rubber. In-situ heating infrared measurements on the contaminated antigorite and Tagish Lake showed decrease of the 1262 /cm (Si-CH3) and 2963 /cm (CH3) peaks from room temperature to 200-300 C indicating desorption of volatile contaminants. These results indicate that careful preparation and storage are

  16. Powder X-Ray Diffraction of the Grain Components of Carbonaceous Chondrite Meteorites.

    Science.gov (United States)

    Furton, D. G.; Hurt, Kendra; Bos, Abram

    Carbonaceous chondrite meteorites are thought to bring to Earth samples of primordial interstellar material. Detailed chemical analysis of meteorites representative of this class (i.e., Allende, Murchison, and Orgueil) establish the primordial character of the material they include and, among other things, reveal that nanometer-sized diamond grains are present in the carbonaceous component of these meteorites at about the 1,000 ppm level (Lewis et al. 1987, Nature, 326, 160). The high abundance of nanodiamonds in these meteoritic samples contributes to the hypothesis that nanodiamonds are present in the interstellar medium at relatively high abundance, but direct observational support of this hypothesis is not so conclusive. (It may also be, according to Dai et al. (2002, Nature, 418, 157), that the nanodiamond grains were formed in situ). On the other hand, there is a growing body of observational evidence that indicates nanometer-sized silicon grains are present in the interstellar medium at relatively high abundance (e.g., Smith & Witt 2001, ApJ, 565, 304). But, silicon nanoparticles have yet to be discovered in a sample of carbonaceous chondrite meteorite. It is relevant in this context that the chemical process that has been used to extract nanodiamond grains from meteoritic samples involves dissolving in strong acid the silicate component of the meteorite. The process is ultimately destructive to any silicon grains that may be present and possibly even alters the nanodiamonds it is used to extract (Mutschke et al. 1995, ApJL, 454, L160). There does not appear to be a similar chemical process that could be used to extract silicon nanoparticles from meteoritic samples. We are in the process of establishing to what extent powder X-ray diffraction can be use as a non-destructive analytical tool to examine nanometer-sized grain components of carbonaceous chondrite meteorites. We present powder X-ray diffraction patterns obtained from samples of the Murchison and

  17. Experimental simulation of organic matter alteration in carbonaceous chondrites under an in situ micro FTIR spectroscopy

    Science.gov (United States)

    Kebukawa, Y.; Nakashima, S.; Saiki, K.; Zolensky, M. E.

    2007-12-01

    Carbonaceous chondrites contain organic matter up to a few weight percents, most of which consists of kerogen- like macromolecular material. Chondritic organic matter preserves signatures of various evolutional steps from presolar materials, through aqueous alteration and thermal metamorphism in the parent asteroid up to delivery to the Earth. The organic-mineral interactions during these processes are little known. We report here on the experimental simulation of organic matter alteration on carbonaceous chondrite parent body under micro FTIR spectroscopy with a heating stage. Leonardite humic acid (IHSS standard humic acid) and synthetic saponite or natural antigorite were used as the macromolecular organic matter and the matrix mineral. These powdered samples were dispersed by MilliQ water then dropped on a CaF2 plate and dried. They were heated in the heating stage from room temperature to 600 °C with a heating rate of 10 °C/min in air, Ar gas, and H2+CO2 gas mixture (mixing ratio 1:1). H2+CO2 gas mixture enables controls of not only oxygen fugacity but also water vapor fugacity, and aqueous processing on chondrite parent bodies can be partly simulated. IR spectra were collected at every 20 °C under the micro FTIR spectroscopy. Aliphatic C-H increased from room temperature to approximately 250 °C then decreased. Aromatic C-H increased from room temperature to around 400-450 °C then decreased. These aliphatic C-H decrease and aromatic C-H increase are faster in air than in Ar or H2+CO2. These CH changes of leonardite humic acid are slower with the presence of saponite. These results indicate that organic matter transformation might be prevented by the clay mineral (saponite). Some carbonaceous chondrite samples mixed with the organic material (leonardite humic acid) will also be investigated by the same way. These results will elucidate interactions of chondritic macromolecular organic matter with matrix minerals during parent body processes.

  18. Electrical conductivity of carbonaceous chondrites and electric heating of meteorite parent bodies

    Science.gov (United States)

    Duba, AL

    1987-01-01

    Electromagnetic heating of rock-forming materials most probably was an important process in the early history of the solar system. Electrical conductivity experiments of representative materials such as carbonaceous chondrites are necessary to obtain data for use in electromagnetic heating models. With the assumption that carbon was present at grain boundaries in the material that comprised the meteorite parent bodies, the electrical heating of such bodies was calculated as a function of body size and solar distance using the T-Tauri model of Sonett and Herbert (1977). The results are discussed.

  19. A hypothesis on the origin of C-type asteroids and carbonaceous chondrites

    CERN Document Server

    Busarev, V V

    2012-01-01

    A hypothesis based on observational and theoretical results on the origin of C-type asteroids and carbonaceous chondrites is proposed. Asteroids of C-type and close BGF-types could form from hydrated silicate-organic matter accumulated in the cores of water-differentiated (due to 26Al and other short-lived isotopes decay) bodies existed in the growth zones of Jupiter. Gravitational scattering of such bodies by Jupiter at its final stage of formation to the main asteroid belt might have led to fragmentation and re-accretion of their primitive materials on the surfaces of many asteroids and/or asteroid parent bodies. The hypothesis makes clear a row of long-standing puzzling facts, the main of which are as follows. The low-albedo and carbonaceous-chondritic surface properties of (1) Ceres contradict to its probable differentiated structure and icy crust (e. g., Thomas et al., 2005, Nature 437: 224-226; Castillo-Rogez et al., 2010, Icarus 205, 443-459), but it could be explained by the process of primitive matte...

  20. The Effect of Aqueous Alteration in Antarctic Carbonaceous Chondrites from Comparative ICP-MS Bulk Chemistry

    Science.gov (United States)

    Alonso-Azcarate, J.; Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Zolensky, M.

    2014-01-01

    Terrestrial ages of Antarctic carbonaceous chondrites (CC) indicate that these meteorites have been preserved in or on ice for, at least, tens of thousands of years. Due to the porous structure of these chondrites formed by the aggregation of silicate-rich chondrules, refractory inclusions, metal grains, and fine-grained matrix materials, the effect of pervasive terrestrial water is relevant. Our community defends that pristine CC matrices are representing samples of scarcely processed protoplanetary disk materials as they contain stellar grains, but they might also trace parent body processes. It is important to study the effects of terrestrial aqueous alteration in promoting bulk chemistry changes, and creating distinctive alteration minerals. Particularly because it is thought that aqueous alteration has particularly played a key role in some CC groups in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive. With the goal to learn more about terrestrial alteration in Antarctica we are obtaining reflectance spectra of CCs, but also performing ICP-MS bulk chemistry of the different CC groups. A direct comparison with the mean bulk elemental composition of recovered falls might inform us on the effects of terrestrial alteration in finds. With such a goal, in the current work we have analyzed some members representative of CO and CM chondrite groups.

  1. Rapid Contamination During Storage of Carbonaceous Chondrites Prepared for Micro FTIR Measurements

    Science.gov (United States)

    Kebukawa, Yoko; Nakashima, Satoru; Otsuka, Takahiro; Nakamura-Messenger, Keiko; Zolensky, ichael E.

    2008-01-01

    The carbonaceous chondrites Tagish Lake and Murchison, which contain abundant hydrous minerals, when pressed on aluminum plates and analyzed by micro FTIR, were found to have been contaminated during brief (24 hours) storage. This contamination occurred when the samples were stored within containers which included silicone rubber, silicone grease or adhesive tape. Long-path gas cell FTIR measurements for silicone rubber revealed the presence of contaminant volatile molecules having 2970 cm(sup -1) (CH3) and 1265 cm(sup -1) (Si-CH3) peaks. These organic contaminants are found to be desorbed by in-situ heating infrared measurements from room temperature to 200-300 C. Careful preparation and storage are therefore needed for precious astronomical samples such as meteorites, IDPs and mission returned samples from comets, asteroids and Mars, if useful for FTIR measurements are to be made.

  2. Carbon, hydrogen and nitrogen isotopes in solvent-extractable organic matter from carbonaceous chondrites

    Science.gov (United States)

    Becker, R. H.; Epstein, S.

    1982-01-01

    CCl4 and CH3OH solvent extractions were performed on the Murray, Murchison, Orgueil and Renazzo carbonaceous chondrites. Delta-D values of +300-+500% are found in the case of the CH3OH-soluble organic matter. The combined C, H and N isotope data makes it unlikely that the CH3OH-soluble components are derivable from, or simply related to, the insoluble organic polymer found in the same meteorites. A relation between the event that formed hydrous minerals in CI1 and CM2 meteorites and the introduction of water- and methanol-soluble organic compounds is suggested. Organic matter soluble in CCl4 has no N, and delta-C-13 values are lower than for CH3OH-soluble phases. It is concluded that there either are large isotopic fractionations for carbon and hydrogen between different soluble organic phases, or the less polar components are partially of terrestrial origin.

  3. The identification of group II inclusions in carbonaceous chondrites by electron probe microanalysis of perovskite

    Science.gov (United States)

    Kornacki, A. S.; Wood, J. A.

    1985-01-01

    The technique developed by Kornacki (1984) for identifying group II Ca/Al-rich inclusions in carbonaceous chondrites by electron-microprobe analysis of the ZrO2 or Y2O3 content of their perovskite component is demonstrated using material from 20 Allende inclusions. The results are presented in tables and graphs and compared with findings obtained by other procedures. Group II inclusions are found to have perovskites generally containing less than 0.10 wt pct ZrO2 and/or Y2O3 (average of several grains), while those of groups I, III, V, and VI have more than 0.25 wt pct ZrO2. Analysis of data on eight Allende Ca/Al-rich inclusions shows that 75 percent of the fine-grained inclusions belong to group II. The implications of these findings for fractionation processes in the primitive solar nebula are indicated.

  4. Ordered mixed-layer structures in the Mighei carbonaceous chondrite matrix

    Science.gov (United States)

    Mackinnon, I. D. R.

    1982-01-01

    High resolution transmission electron microscopy of the Mighei carbonaceous chondrite matrix has revealed the presence of a new mixed layer structure material. This mixed-layer material consists of an ordered arrangement of serpentine-type (S) and brucite-type (B) layers in the sequence SBBSBB. Electron diffraction and imaging techniques show that the basal periodicity is approximately 17 A. Discrete crystals of SBB-type material are typically curved, of small size (less than 1 micron) and show structural variations similar to the serpentine group minerals. Mixed-layer material also occurs in association with planar serpentine. Characteristics of SBB-type material are not consistent with known terrestrial mixed-layer clay minerals. Evidence for formation by a condensation event or by subsequent alteration of pre-existing material is not yet apparent.

  5. Molecular Composition of Carbonaceous Globules in the Bells (CM2) Chondrite

    Science.gov (United States)

    Clemett, S. J.; Nakamura-Messenger, K.; Thomas-Keprta, K. L.; Robinson, G.-A.; Mckay, D. S.

    2009-01-01

    Some meteorites and IDPs contain micron-size carbonaceous globules that are associated with significant H and/or N isotopic anomalies. This has been interpreted as indicating that such globules may contain at least partial preserved organic species formed in the outer reaches of the proto-solar disk or the presolar cold molecular cloud. Owing to their small sizes, relatively little is known about their chemical compositions. Here we present in situ measurements of aromatic molecular species in organic globules from the Bells (CM2) chondrite by microprobe two-step laser mass spectrometry. This meteorite was chosen for study because we have previously found this meteorite to contain high abundances of globules that often occur in clusters. The Bells (CM2) globules are also noteworthy for having particularly high enrichments in H-2. and N-15. In this study, we identified individual globules and clusters of globules using native UV fluorescence.

  6. Radar-Enabled Recovery of the Sutters Mill Meteorite, a Carbonaceous Chondrite Regolith Breccia

    Science.gov (United States)

    Jenniskens, Petrus M.; Fries, Marc D.; Yin, Qing-Zhu; Zolensky, Michael E.; Krot, Alexander N.; Sandford, Scott A.; Sears, Derek; Beauford, Robert; Ebel, Denton S.; Friedrich, Jon M.; Nagashima, Kazuhide; Wimpenny, Josh; Yamakawa, Akane; Nishiizumi, Kunihiko; Hamajima, Yasunori; Caffee, Marc W.; Welten, Kees C.; Laubenstein, Matthias; Davis, Andrew M.; Simon, Steven B.; Heck, Phillipp R.; Young, Edward D.; Kohl, Issaku E.; Thiemens, Mark H.; Nunn, Morgan H.; Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Cahill, Thomas A.; Lawton, Jonathan A.; Barnes, David; Steele, Andrew; Rochette, Pierre; Verosub, Kenneth L.; Gattacceca, Jerome

    2012-01-01

    Doppler weather radar imaging enabled the rapid recovery of the Sutter's Mill meteorite after a rare 4-kiloton of TNT-equivalent asteroid impact over the foothills of the Sierra Nevada in northern California. The recovered meteorites survived a record high-speed entry of 28.6 kilometers per second from an orbit close to that of Jupiter-family comets (Tisserand's parameter = 2.8 +/- 0.3). Sutter's Mill is a regolith breccia composed of CM (Mighei)-type carbonaceous chondrite and highly reduced xenolithic materials. It exhibits considerable diversity of mineralogy, petrography, and isotope and organic chemistry, resulting from a complex formation history of the parent body surface. That diversity is quickly masked by alteration once in the terrestrial environment but will need to be considered when samples returned by missions to C-class asteroids are interpreted.

  7. Radar-enabled recovery of the Sutter's Mill meteorite, a carbonaceous chondrite regolith breccia.

    Science.gov (United States)

    Jenniskens, Peter; Fries, Marc D; Yin, Qing-Zhu; Zolensky, Michael; Krot, Alexander N; Sandford, Scott A; Sears, Derek; Beauford, Robert; Ebel, Denton S; Friedrich, Jon M; Nagashima, Kazuhide; Wimpenny, Josh; Yamakawa, Akane; Nishiizumi, Kunihiko; Hamajima, Yasunori; Caffee, Marc W; Welten, Kees C; Laubenstein, Matthias; Davis, Andrew M; Simon, Steven B; Heck, Philipp R; Young, Edward D; Kohl, Issaku E; Thiemens, Mark H; Nunn, Morgan H; Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Cahill, Thomas A; Lawton, Jonathan A; Barnes, David; Steele, Andrew; Rochette, Pierre; Verosub, Kenneth L; Gattacceca, Jérôme; Cooper, George; Glavin, Daniel P; Burton, Aaron S; Dworkin, Jason P; Elsila, Jamie E; Pizzarello, Sandra; Ogliore, Ryan; Schmitt-Kopplin, Phillipe; Harir, Mourad; Hertkorn, Norbert; Verchovsky, Alexander; Grady, Monica; Nagao, Keisuke; Okazaki, Ryuji; Takechi, Hiroyuki; Hiroi, Takahiro; Smith, Ken; Silber, Elizabeth A; Brown, Peter G; Albers, Jim; Klotz, Doug; Hankey, Mike; Matson, Robert; Fries, Jeffrey A; Walker, Richard J; Puchtel, Igor; Lee, Cin-Ty A; Erdman, Monica E; Eppich, Gary R; Roeske, Sarah; Gabelica, Zelimir; Lerche, Michael; Nuevo, Michel; Girten, Beverly; Worden, Simon P

    2012-12-21

    Doppler weather radar imaging enabled the rapid recovery of the Sutter's Mill meteorite after a rare 4-kiloton of TNT-equivalent asteroid impact over the foothills of the Sierra Nevada in northern California. The recovered meteorites survived a record high-speed entry of 28.6 kilometers per second from an orbit close to that of Jupiter-family comets (Tisserand's parameter = 2.8 ± 0.3). Sutter's Mill is a regolith breccia composed of CM (Mighei)-type carbonaceous chondrite and highly reduced xenolithic materials. It exhibits considerable diversity of mineralogy, petrography, and isotope and organic chemistry, resulting from a complex formation history of the parent body surface. That diversity is quickly masked by alteration once in the terrestrial environment but will need to be considered when samples returned by missions to C-class asteroids are interpreted. PMID:23258889

  8. In situ observation of D-rich carbonaceous globules embedded in NWA 801 CR2 chondrite

    Science.gov (United States)

    Hashiguchi, Minako; Kobayashi, Sachio; Yurimoto, Hisayoshi

    2013-12-01

    Eighty-five D-rich carbonaceous particles were identified in the matrix of the NWA 801 CR2 chondrite using isotope microscopy. The occurrence of 67 D-rich carbonaceous particles was characterized using secondary electron microscopy combined with X-ray elemental mapping. The close association of H and C, and D-enrichment suggests that the D-rich carbonaceous particles correspond to organic matter. The D-rich organic particles were scattered ubiquitously throughout the matrix at a concentration of approximately 660 ppm. The morphology of the D-rich carbonaceous particles is globular up to about 1 μm in diameter and is classified into four types: ring globules, round globules, irregular-shaped globules, and globule aggregates. The ring globules are ring-shaped organic matter containing silicate and/or oxide, with or without a void in the center. This is the first report of silicate and oxide grains surrounded by D-rich organic matter. The globule aggregates are composed of several D-rich organic globules mixed with silicates. Morphology of ring globules is very similar to core-mantle grain produced in the molecular cloud or in the outer solar nebula inferring by astronomy, suggesting that the organic globules have formed by UV photolysis in the ice mantle. Silicates or oxides attached to D-rich organic globules are the first observation among chondrites so far and may be unique nature of CR2 chondrites. The hydrogen isotopic compositions of the ring globules, round globules, irregular-shaped globules, and globule aggregates are δD = 3000-4800, 2900-8100, 2700-11,000, and 2500-11,000‰, respectively. Variations of D/H ratio of these organic globules seemed to be attributed to variations of D/H ratio of the organic radicals or differences of content of the D-rich organic radicals. There are no significant differences in the hydrogen isotopic compositions among the four types of D-rich carbonaceous matter. The D-enrichments suggest that these organic globules have

  9. Magnetite-sulfide chondrules and nodules in CK carbonaceous chondrites - Implications for the timing of CK oxidation

    Science.gov (United States)

    Rubin, Alan E.

    1993-01-01

    CK carbonaceous chondrites contain rare (about 0.1 vol pct) magnetite-sulfide chondrules that range from about 240 to 500 microns in apparent diameter and have ellipsoidal to spheroidal morphologies, granular textures, and concentric layering. They resemble the magnetite-sulfide nodules occurring inside mafic silicate chondrules in CK chondrites. It seems likely that the magnetite-sulfide chondrules constitute the subset of magnetite-sulfide nodules that escaped as immiscible droplets from their molten silicate chondrule hosts during chondrule formation. The intactness of the magnetite-sulfide chondrules and nodules implies that oxidation of CK metal occurred before agglomeration. Hence, the pervasive silicate darkening of CK chondrites was caused by the shock mobilization of magnetite and sulfide, not metallic Fe-Ni and sulfide as in shock-darkened ordinary chondrites.

  10. A plausible link between the asteroid 21 Lutetia and CH carbonaceous chondrites

    CERN Document Server

    Moyano-Cambero, Carles E; Llorca, Jordi; Fornasier, Sonia; Barucci, Maria A; Rimola, Albert

    2016-01-01

    A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ultraviolet to near-infrared (0.3 to 2.2 {\\mu}m) and in the mid-infrared to thermal infrared (2.5 to 30.0 {\\mu}m or 4000 to ~333 cm^-1), and they are compared here to spectra from the asteroid 21 Lutetia. There are several similarities in absorption bands and overall spectral behavior between this CH3 meteorite and 21 Lutetia. Considering also that the bulk density of Lutetia is similar to that of CH chondrites, we suggest that this asteroid could be similar, or related to, the parent body of these meteorites, if not the parent body itself. However, the apparent surface diversity of Lutetia pointed out in previous studi...

  11. Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

    Science.gov (United States)

    Burton, Aaron, S.; Berger, Eve L.; Locke, Darren R.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

    2015-01-01

    Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

  12. Extended chronologies of aqueous alteration in the CM2 carbonaceous chondrites: evidence from carbonates in Queen Alexandra Range 93005

    OpenAIRE

    Lee, M.; Lindgren, P.; Sofe, M.; Alexander, C.; Wang, J.

    2012-01-01

    The Antarctic CM2 carbonaceous chondrite QUE 93005 contains four compositionally distinct carbonates, namely breunnerite, calcite, dolomite and a Ca-poor dolomite. These carbonates can form monomineralic grains, or may be intergrown as bimineralic grains consisting of dolomite plus breunnerite and dolomite plus calcite, or polymineralic grains containing an intergrowth of breunnerite, Ca-poor dolomite and calcite. Carbonates in all grain types have inclusions of Fe,Ni sulphides and/or Mg-Fe p...

  13. Crystallography of Magnetite Plaquettes and their Significance as Asymmetric Catalysts for the Synthesis of Chiral Organics in Carbonaceous Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.

    2015-01-01

    We have previously observed the magnetite plaquettes in carbonaceous chondrites using scanning electron microscope (SEM) imaging, examined the crystal orientation of the polished surfaces of magnetite plaquettes in CI Orgueil using electron backscattered diffraction (EBSD) analysis, and concluded that these magnetite plaquettes are likely naturally asymmetric materials. In this study, we expanded our EBSD observation to other magnetite plaquettes in Orgueil, and further examined the internal structure of these remarkable crystals with the use of X-ray computed microtomography.

  14. Metamorphosed CM and CI Carbonaceous Chondrites Could Be from the Breakup of the Same Earth-crossing Asteroid

    Science.gov (United States)

    Zolensky, Michael; Abell, Paul; Tonui, Eric

    2005-01-01

    Far from being the relatively unprocessed materials they were once believed to be, we now know that a significant number of carbonaceous chondrites were thermally metamorphosed on their parent asteroid(s). Numerous studies indicate that 7 "CM" and 2 "CI" chondrites have been naturally heated, variously, at from 400 to over 700 C on their parent asteroid(s). Petrographic textures reveal that this thermal metamorphism occurred after the dominant aqueous alteration phase, although some meteorites show evidence of a heating event between two aqueous alteration episodes, i.e. pro- and retrograde aqueous alteration. Aside from the issues of the identification of the transient heat source, timing of metamorphism, and the relation of these materials (if any) to conventional CM and CI chondrites, there is also a mystery related to their recovery. All of these meteorites have been recovered from the Antarctic; none are falls or finds from anyplace else. Indeed, the majority have been collected by the Japanese NIPR field parties in the Yamato Mountains. In fact, one estimate is that these meteorites account for approx. 64 wt% of the CM carbonaceous chondrites at the NIPR. The reasons for this are unclear and might be due in part to simple sampling bias. However we suggest that this recovery difference is related to the particular age of the Yamato Mountains meteorite recovery surfaces, and differences in meteoroid fluxes between the Yamato meteorites and recent falls and substantially older Antarctic meteorites. Additional information is included in the original extended abstract.

  15. Chondrules in CK carbonaceous chondrites and thermal history of the CV-CK parent body

    Science.gov (United States)

    Chaumard, NoëL.; Devouard, Bertrand

    2016-03-01

    CK chondrites are the only group of carbonaceous chondrites with petrologic types ranging from 3 to 6. It is commonly reported than ~15 vol% of CK4-6 samples are composed of chondrules. The modal abundance of chondrules estimated here for 18 CK3-6 (including five CK3s) ranges from zero (totally recrystallized) to 50.5%. Although almost all chemically re-equilibrated with the host matrix, we recognized in CK3s and Tanezrouft (Tnz) 057 (CK4) up to 85% of chondrules as former type I chondrules. Mean diameters of chondrules range from 0.22 to 1.05 mm for Karoonda (CK4) and Tnz 057 (CK4), respectively. Up to ~60% of chondrules in CK3-4 are surrounded by igneous rims (from ~20 μm to 2 mm width). Zoned olivines were found in unequilibrated chondrules from DaG 431 (CK3-an), NWA 4724 (CK3.8), NWA 4423 (CK3.9), and Tnz 057 (CK4). We modeled Fe/Mg interdiffusion profiles measured in zoned olivines to evaluate the peak metamorphic temperatures and time scales of the CK parent body metamorphism, and proposed a two-stage diffusion process in order to account for the position of inflection points situated within chondrules. Time scales inferred from Fe/Mg interdiffusion in olivine from unequilibrated chondrules are on the order of tens to a hundred thousand years (from 50 to 70,000 years for peak metamorphic temperatures of 1140 and 920 K, respectively). These durations are longer than what is commonly accepted for shock metamorphism and shorter than what is required for nuclide decay. Using the concept of a continuous CV-CK metamorphic series, which is reinforced by this study, we estimated peak metamorphic temperatures <850 K for CV, 850-920 K for CK3, and 920-1140 K for CK4-6 chondrites considering a duration of 70,000 years.

  16. Matrix phyllosilicates and associated minerals in C2M carbonaceous chondrites

    Science.gov (United States)

    Barber, D. J.

    1981-06-01

    TEM, HRTEM, HVEM, and SEM methods, coupled with energy dispersive X-ray analysis, are used in studying the microstructure and the phases making up the matrix of the carbonaceous chondrites Murchison, Cold Bokkeveld, Nawapali, and Cochabamba. A wide variety of phyllosilicate morphologies is found to occur in each. It is noted that very small crystals and clasts of olivine, pyroxene and other unhydrated minerals are mixed intimately with the phyllosilicates. Intergrowths of carbonates and sulfides within the phyllosilicates also occur, as does a ubiquitous spongy material which though difficult to characterize contains elementary phyllosilicate units and embryo crystals. The identifiable large crystalline phyllosilicates are mainly Fe-rich serpentine-group minerals and intermediate more Mg-rich chrysotilelike group members, with characteristic basal layer spacings of approximately 7.0-7.4 A. It is found that the Fe/Si and Mg/Si ratios vary on a sub-micron scale and that the morphologies of the larger phyllosilicate crystals correlate broadly with these variations. Small crystals of sodium chloride and potassium chloride are identified, occluded with a predominantly organic mass.

  17. Application of Scanning-Imaging X-Ray Microscopy to Fluid Inclusion Candidates in Carbonates of Carbonaceous Chondrites

    Science.gov (United States)

    Tsuchiyama, Akira; Nakano, Tsukasa; Miyake, Akira; Akihisa, Takeuchi; Uesugi, Kentaro; Suzuki, Yoshio; Kitayama, Akira; Matsuno, Junya; Zolensky, Michael E.

    2016-01-01

    In order to search for such fluid inclusions in carbonaceous chondrites, a nondestructive technique using x-ray micro-absorption tomography combined with FIB sampling was developed and applied to a carbonaceous chondrite. They found fluid inclusion candidates in calcite grains, which were formed by aqueous alteration. However, they could not determine whether they are really aqueous fluids or merely voids. Phase and absorption contrast images can be simultaneously obtained in 3D by using scanning-imaging x-ray microscopy (SIXM). In refractive index, n=1-sigma+i(beta), in the real part, 1-sigma is the refractive index with decrement, sigma, which is nearly proportional to the density, and the imaginary part, beta, is the extinction coefficient, which is related to the liner attenuation coefficient, mu. Many phases, including water and organic materials as well as minerals, can be identified by SIXM, and this technique has potential availability for Hayabusa-2 sample analysis too. In this study, we examined quantitative performance of d and m values and the spatial resolution in SIXM by using standard materials, and applied this technique to carbonaceous chondrite samples. We used POM ([CH2O]n), silicon, quartz, forsterite, corundum, magnetite and nickel as standard materials for examining the sigma and mu values. A fluid inclusion in terrestrial quartz and bi-valve shell (Atrina vexillum), which are composed of calcite and organic layers with different thickness, were also used for examining the spatial resolution. The Ivuna (CI) and Sutter's Mill (CM) meteorites were used as carbonaceous chondrite samples. Rod- or cube-shaped samples 20-30 micron in size were extracted by using FIB from cross-sectional surfaces of the standard materials or polished thin sections of the chondrites, which was previously observed with SEM. Then, the sample was attached to a thin W-needle and imaged by SIXM system at beamline BL47XU, SPring-8, Japan. The slice thickness was 109.3 nm

  18. Magnetite as Possible Template for the Synthesis of Chiral Organics in Carbonaceous Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.

    2014-01-01

    The main goal of the Japanese Aerospace Ex-ploration Agency (JAXA) Hayabusa-2 mission is to visit and return to Earth samples of a C-type asteroid (162173) 1999 JU3 in order to understand the origin and nature of organic materials in the Solar System. Life on Earth shows preference towards the set of organics with particular spatial arrangements, this 'selectivity' is a crucial criterion for life. With only rare exceptions, life 'determines' to use the left- (L-) form over the right- (D-) form of amino acids, resulting in a L-enantiomeric excess (ee). Recent studies have shown that L-ee is found within the alpha-methyl amino acids in meteorites [1, 2], which are amino acids with rare terrestrial occurrence, and thus point towards a plausible abiotic origin for ee. One of the proposed origins of chiral asymmetry of amino acids in meteorites is their formation with the presence of asymmetric catalysts [3]. The catalytic mineral grains acted as a surface at which nebular gases (CO, H2 and NH3) were allowed to condense and react through Fisher Tropsch type (FTT) syntheses to form the organics observed in meteorites [4]. Magnetite is shown to be an effective catalyst of the synthesis of amino acids that are commonly found in meteorites [5]. It has also taken the form as spiral magnetites (a.k.a. 'plaquettes'), which were found in various carbonaceous chondrites (CCs), including C2s Tagish Lake and Esseibi, CI Orgueil, and CR chondrites [e.g., 6, 7, 8]. In addition, L-ee for amino acids are common in the aqueously altered CCs, as opposed to the unaltered CCs [1]. It seems possible that the synthesis of amino acids with chiral preferences is correlated to the alteration process experienced by the asteroid parent body, and related to the configuration of spiral magnetite catalysts. Since C-type asteroids are considered to be enriched in organic matter, and the spectral data of 1999 JU3 indicates a certain de-gree of aqueous alteration [9], the Hayabusa-2 mission serves as

  19. Bidirectional reflectance spectroscopy of carbonaceous chondrites: Implications for water quantification and primary composition

    Science.gov (United States)

    Garenne, A.; Beck, P.; Montes-Hernandez, G.; Brissaud, O.; Schmitt, B.; Quirico, E.; Bonal, L.; Beck, C.; Howard, K. T.

    2016-01-01

    In this study, we measured bidirectional reflectance spectra (0.5-4.0 μm) of 24 CMs, five CRs, one CI, one CV, and one C2 carbonaceous chondrites. These meteorites are known to have experienced an important variability in their relative degrees of aqueous alteration degree (Rubin et al. [2007]. Geochim. Cosmochim. Acta 71, 2361-2382; Howard et al. [2009]. Geochim. Cosmochim. Acta 73, 4576-4589; Howard et al. [2011]. Geochim. Cosmochim. Acta 75, 2735-2751; Alexander et al. [2013]. Geochim. Cosmochim. Acta 123, 244-260). These measurements were performed on meteorite powders inside an environmental cell under a primary vacuum and heated at 60 °C in order to minimize adsorbed terrestrial water. This protocol allows controlling of atmospheric conditions (i.e. humidity) in order to avoid contamination by terrestrial water. We discuss various spectral metrics (e.g. reflectance, band depth, single-scattering albedo, …) in the light of recent bulk composition characterization (Howard et al. [2009]. Geochim. Cosmochim. Acta 73, 4576-4589; Howard et al. [2015]. Geochim. Cosmochim. Acta 149, 206-222; Alexander et al. [2012]. Science 337, 721; Beck et al. [2014]. Icarus 229, 263-277; Garenne et al. [2014]. Geochim. Cosmochim. Acta 137, 93-112). This study reveals variability of reflectance among meteorite groups. The reflectance is not correlated with carbon or hydrogen abundance neither with measured grain size distribution. We suggest that it is rather controlled by the nature of accreted components, in particular the initial matrix/chondrule proportion. Band depth, integrated band depth, mean optical path length, normalized optical path length, effective single-particle absorption thickness were calculated on the so called 3-μm band for reflectance spectra and for single scattering albedo spectra. They were compared with hydrated phase proportions from previous study on the same meteorites by thermogravimetric analyses and infrared spectroscopy in transmission. We find

  20. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite

    OpenAIRE

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A.; Ouyang, Ziyuan; Wang, Daode

    2005-01-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are ≈5 × 10-6. Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by sol...

  1. Hydrothermal alteration of CM carbonaceous chondrites: Implications of the identification of tochilinite as one type of meteoritic PCP

    Science.gov (United States)

    Zolensky, M. E.

    1984-01-01

    Poorly characterized phases (PCP's) constitute up to 30 volume percent of some CM carbonaceous chondrites, and are therefore an important key to an understanding of the physico-chemical conditions attending matrix evolution. An iron rich form of the terrestrial phase tochilinite was recently identified as a common type of PCP. Tochilinite has the general formula 6Fe(0.9)S.5(Mg,Fe)(OH)2 and consists of alternating machinawite (FeS) and brucite ((Mg,Fe)(OH)2) sheets, with iron vacancies in the sulfide sheets. In iron rich tochilinite, ferrous hydroxide, called amakinite, replaces brucite. If CM carbonaceous kchondrites have underdone hydrothermal alteration, iron rich tochilinite, at least, probably grew from aqueous solutions characterized by low FO2, high FS2, pH 10 to 12, and at a temperature at or below 170 C.

  2. Mercury Abundances and Isotopic Compositions in the Murchison (CM) and Allende (CV)Carbonaceous Chondrites

    Science.gov (United States)

    Lauretta, D. S.; Klaue, B.; Blum, J. D.; Buseck, P. R.

    2001-01-01

    The abundance and isotopic composition of Hg was determined in bulk samples of both the Murchison (CM) and Allende (CV) carbonaceous chondrites using single- and multi-collector inductively coupled plasma mass spectrometry (ICP-MS). The bulk abundances of Hg are 294 6 15 ng/g in Murchison and 30.0 6 1.5 ng/g in Allende. These values are within the range of previous measurements of bulk Hg abundances by neutron activation analysis (NAA). Prior studies suggested that both meteorites contain isotopically anomalous Hg, with d l 96/202Hg values for the anomalous, thermal-release components from bulk samples ranging from 2260 %o to 1440 9/00 in Murchison and from 2620 9/00 to 1540 9/00 in Allende (Jovanovic and Reed, 1976a; 1976b; Kumar and Goel, 1992). Our multi-collector ICP-MS measurements suggest that the relative abundances of all seven stable Hg isotopes in both meteorites are identical to terrestrial values within 0.2 to 0.5 9/00m. On-line thermal-release experiments were performed by coupling a programmable oven with the singlecollector ICP-MS. Powdered aliquots of each meteorite were linearly heated from room temperature to 900 C over twenty-five minutes under an Ar atmosphere to measure the isotopic composition of Hg released fiom the meteorites as a h c t i o n of temperature. In separate experiments, the release profiles of S and Se were determined simultaneously with Hg to constrain the Hg distribution within the meteorites and to evaluate the possibility of Se interferences in previous NAA studies. The Hg-release patterns differ between Allende and Murchison. The Hg-release profile for Allende contains two distinct peaks, at 225" and 343"C, whereas the profile for Murchison has only one peak, at 344 C. No isotopically anomalous Hg was detected in the thermal-release experiments at a precision level of 5 to 30 9/00, depending on the isotope ratio. In both meteorites the Hg peak at ;340"C correlates with a peak in the S-release profile. This correlation

  3. Hydrothermal venting on carbonaceous chondritic elevations on 1 Ceres and 4 Vesta

    Science.gov (United States)

    Hoffmann, Martin; Nathues, Andreas; Platz, Thomas; Thangjam, Guneshwar

    2016-04-01

    Framing Camera images of the Dawn spacecraft [1] led to the discovery of recent geologic activity on Ceres, including deposition of salts, formation of near surface haze [2], and impact associated spectral diversity. More detailed analyses revealed widespread flow features, partly composed of granular material, but also indicating sites of fluidized areas of the surface and sub-surface. The unexpected discovery of deposits of carbonaceous chondritic material on Vesta associated with indications of considerable amounts of volatiles at large impact structures hint at similar processes [3, 4]. Near large crater walls on both proto-/dwarf-planets, montes and domes appear to be associated with uplift and even release of water-driven material including salts and clays [5, 6]. We report morphologic and color band spectroscopic characteristics of selected key features on 1 Ceres and 4 Vesta which demonstrate this context. A first analysis indicates compositional differences of the proportion of the content of salts and phyllosilicates, e. g. on the different elevations of the primary and secondary spots in Occator and some flow features. The distribution and diversity of these color features is further characterized by a comparison with more widespread properties on the whole surface. During this investigation, not only the link between salt deposits and different types of materials at the centers of activity could be described, but we also offer an intriguing new interpretation of one of the most prominent surface features of Vesta: Lucaria Tholus. Several analogies with similar features and properties of Mars [7] further support the view of a related origin. References: [1] Sierks, H. et al., Space Sci. Rev., 163, 263-327, 2011. [2] Nathues, A. et al., Nature 528, 237-240, 2015. [3] Reddy, V. et al. Icarus, 221, 544-559, 2012. [4] Scully, J. E. C. et al., EPSC Abstracts 8, 2013-242-2, 2013. [5] Platz, T. et al. LPSC 2016 [6] Ruesch, O. et al. LPSC 2016 [7] Platz, T. et

  4. Effects of secondary alteration on the composition of free and IOM-derived monocarboxylic acids in carbonaceous chondrites

    Science.gov (United States)

    Aponte, José C.; Alexandre, Marcelo R.; Wang, Yi; Brearley, Adrian J.; Alexander, Conel M. O.'D.; Huang, Yongsong

    2011-05-01

    Monocarboxylic acids (MCAs) are important astrobiologically because they are often the most abundant soluble compounds in carbonaceous chondrites (CCs) and are potential synthetic end products for many biologically important compounds. However, there has been no systematic study on the effect of parent body alteration on molecular and isotopic variability of MCAs. Since MCAs in meteorites are dominated by low molecular weight (C1-C8), highly volatile compounds, their distributions are likely to be particularly sensitive to secondary alteration processes. In contrast, the aliphatic side chains of insoluble organic matter (IOM) in CCs, whose composition has been shown to be closely related to the MCAs, may be far more resistant to secondary alteration. In the present study, we determined the distributions and isotopic ratios of free and IOM-derived MCAs in six carbonaceous chondrites with a range of classifications: Murchison (CM2), EET 87770 (CR2), ALH 83034 (CM1), ALH 83033 (CM2), MET 00430 (CV3) and WIS 91600 (C2). We compare mineralogical and petrological characteristics to the MCAs distributions to better define the processes leading to the synthesis and alteration of meteoritic MCAs. Our results show that aqueous and especially thermal alteration in the parent bodies led to major loss of free MCAs and depletion of straight relative to branched chain compounds. However, the MCAs derived from aliphatic side chains of IOM are well preserved despite of secondary alterations. The molecular and isotopic similarities of IOM-derived MCAs in different chondrite samples indicate very similar synthetic histories for organic matter in different meteorites.

  5. The appearance of Carbonaceous Chondrites on (1) Ceres from observations by the Dawn Framing Camera

    Science.gov (United States)

    Schäfer, Tanja; Schäfer, Michael; Mengel, Kurt; Cloutis, Edward A.; Izawa, Matthew R. M.; Thangjam, Guneshwar; Hoffmann, Martin; Platz, Thomas; Nathues, Andreas; Kallisch, Jan; Ripken, Joachim; Russel, Christopher T.

    2016-04-01

    NASA's Dawn spacecraft reached dwarf planet Ceres in March 2015 and started data acquisition using three different instruments. These are the Framing Camera (FC; [1]), the Visible & Infrared Spectrometer (VIR; [2]), and the Gamma Ray and Neutron Detector (GRaND; [3]). In our work we focus on the potential appearance of carbonaceous chondritic (CC) material on the cerean surface using Dawn FC color mosaics covering the VIS/NIR wavelength region. In preparation of the Dawn arrival at Ceres, a discrimination scheme for CC groups using FC color ratios was developed by [4] and is based on 121 CC laboratory spectra compiled from RELAB. As the cerean surface material mainly differs by its spectral slope over the whole FC wavelength range (0.44-0.97 μm), we classified the color mosaics by this parameter. We applied the CC discrimination scheme only to those regions on the cerean surface (more than 90 %) which exhibit spectral slopes ≥ -1 % reflectance per μm to exclude the strongly negative sloped regions of large young craters such as Occator, Haulani, and Oxo. These are not likely to be similar to pure CC material as can be seen by their brightness and their bluish spectral slope [5]. We found that the surface material of Ceres is, among the suite of CCs, most similar to Ivuna samples artificially heated to 200 and 300°C [6] and unusual CCs, which naturally experienced heating. The latter ones comprise Dhofar 225, Y-86789 and Y-82162, which have been determined to have undergone aqueous alteration and subsequent thermal metamorphism (e.g. [7,8]).Our comparison with VIR data shows, that the spectra of Ivuna heated to 200°C and 300°C match well the OH-absorption at 2.7 μm but do not show the smaller 3.05-3.1 μm absorption observed on Ceres [9,10,11]. Nevertheless, the remarkably flat UV drop-off detected on the cerean surface may, at least spectrally, correspond to highly aqueously altered and subsequently thermally metamorphosed CC material. Further alteration of

  6. Isotopic composition of carbonaceous-chondrite kerogen Evidence for an interstellar origin of organic matter in meteorites

    Science.gov (United States)

    Kerridge, J. F.

    1983-01-01

    Stepwise combustion has revealed systematic patterns of isotopic heterogeneity for C, H and N in the insoluble organic fraction (m-kerogen) from the Orgueil and Murray carbonaceous chondrites. Those patterns are essentially identical for both meteorites, indicating a common source of m-kerogen. The data cannot be reconciled with a single mass-fractionation process acting upon a single precursor composition. This indicates either a multi-path history of mass-dependent processing or a significant nucleogenetic contribution, or both. If mass-fractionation were the dominant process, the magnitude of the observed isotopic variability strongly suggests that ion-molecule reactions at very low temperatures, probably in interstellar clouds, were responsible. In any case, an interstellar, rather than solar nebular, origin for at least some of the meteoritic organic matter is indicated. This has interesting implications for the origin of prebiotic molecules, temperatures in the early solar system, and the isotopic compositions of volatiles accreted by the terrestrial planets.

  7. Primitive Liquid Water of the Solar System in an Aqueous Altered Carbonaceous Chondrite

    Science.gov (United States)

    Tsuchiyama, A.; Miyake, A.; Kitayama, A.; Matsuno, J.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.; Nakano, T.; Zolensky, M. E.

    2016-01-01

    Non-destructive 3D observations of the aqueous altered CM chondrite Sutter's Mill using scanning imaging x-ray microscopy (SIXM) showed that some of calcite and enstatite grains contain two-phase inclusion, which is most probably composed of liquid water and bubbles. This water should be primitive water responsible for aqueous alteration in an asteroid in the early solar system.

  8. Ca-, Al-rich Inclusions in Three New Carbonaceous Chondrites from the Grove Mountains, Antarctica:New Evidence for a Similar Origin of the Objects in Various Groups of Chondrites

    Institute of Scientific and Technical Information of China (English)

    DAI Deqiu; LIN Yangting; MIAO Bingkui; SHENG Wenjie; WANG Daode

    2004-01-01

    Three new carbonaceous chondrites (GRV 020025, 021579 and 022459) collected from the Grove Mountains(GRV), Antarctica, have been classified as the CM2, CO3 and CV3 chondrites, respectively. A total of 27 Ca- and Al-rich inclusions have been found in the three meteorites, which are the earliest assemblages formed in the solar nebula. Most of the inclusions are intensively altered, with abundant phyllosilicates in the inclusions from GRV 020025 and FeO enrichment of spinel in those from GRV 022459. Except for one spinel-spherule in each of GRV 020025 and 021579, all the inclusions can be classified as Type A-like or spinel-pyroxene-rich inclusions, and they probably represent the continuum of solar nebular condensation. In addition, most of the inclusions in these meteorites share much similarity in both petrography and mineral chemistry, suggesting a similar origin of Ca-Al-rich inclusions in various chondrites.

  9. Isotopic evidence for primordial molecular cloud material in metal-rich carbonaceous chondrites

    DEFF Research Database (Denmark)

    Van Kooten, Elishevah M M E; Wielandt, Daniel; Schiller, Martin;

    2016-01-01

    The short-lived (26)Al radionuclide is thought to have been admixed into the initially (26)Al-poor protosolar molecular cloud before or contemporaneously with its collapse. Bulk inner Solar System reservoirs record positively correlated variability in mass-independent (54)Cr and (26)Mg*, the decay......)Mg*-depleted and (54)Cr-enriched component. This composition is consistent with that expected for thermally unprocessed primordial molecular cloud material before its pollution by stellar-derived (26)Al. The (26)Mg* and (54)Cr compositions of bulk metal-rich chondrites require significant amounts (25...

  10. Planetary Bioresources and Astroecology. 1. Planetary Microcosm Bioassays of Martian and Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, and Algal and Plant Responses

    Science.gov (United States)

    Mautner, Michael N.

    2002-07-01

    The biological fertilities of planetary materials can be assessed using microcosms based on meteorites. This study applies microcosm tests to martian meteorites and analogues and to carbonaceous chondrites. The biological fertilities of these materials are rated based on the soluble electrolyte nutrients, the growth of mesophile and cold-tolerant algae, and plant tissue cultures. The results show that the meteorites, in particular the Murchison CM2 carbonaceous chondrite and DaG 476 martian shergottite, contain high levels of water-extractable Ca, Mg, and SO 4-S. The martian meteorites DaG 476 and EETA 79001 also contain higher levels of extractable essential nutrients NO 3-N (0.013-0.017 g kg -1) and PO 4-P (0.019-0.046 g kg -1) than the terrestrial analogues. The yields of most of the water-extractable electrolytes vary only by factors of 2-3 under a wide range of planetary conditions. However, the long-term extractable phosphate increases significantly under a CO 2 atmosphere. The biological yields of algae and plant tissue cultures correlate with extractable NO 3-N and PO 4-P, identifying these as the limiting nutrients. Mesophilic algae and Asparagus officinalis cultures are identified as useful bioassay agents. A fertility rating system based on microcosm tests is proposed. The results rate the fertilities in the order martian basalts > terrestrial basalt, agricultural soil > carbonaceous chondrites, lava ash > cumulate igneous rock. The results demonstrate the application of planetary microcosms in experimental astroecology to rate planetary materials as targets for astrobiology exploration and as potential space bioresources. For example, the extractable materials in Murchison suggest that concentrated internal solutions in carbonaceous asteroids (3.8 mol L -1 electrolytes and 10 g L -1 organics) can support and disperse microorganisms introduced by natural or directed panspermia in early solar systems. The results also suggest that carbonaceous asteroids

  11. Origin of organic matter in the early solar system. VII - The organic polymer in carbonaceous chondrites

    Science.gov (United States)

    Hayatsu, R.; Matsuoka, S.; Anders, E.; Scott, R. G.; Studier, M. H.

    1977-01-01

    Degradation techniques, including pyrolysis, depolymerization, and oxidation, were used to study the insoluble polymer from the Murchison C2 chondrite. Oxidation with Cr2O7(2-) or O2/UV led to the identification of 15 aromatic ring systems. Of 11 aliphatic acids identified, three dicarboxylic acids presumably came from hydroaromatic portions of the polymer, whereas eight monocarboxylic acids probably derive from bridging groups or ring substituents. Depolymerization with CF3COO4 yielded some of the same ring systems, as well as alkanes (C1 through C8) and alkenes (C2 through C8), alkyl (C1 through C5) benzenes and naphthalenes, and methyl- or dimethyl -indene, -indane, -phenol, -pyrrole, and -pyridine. All these compounds were detected below 200 C, and are therefore probably indigenous constituents. The properties of the meteoritic polymer were compared with the properties of a synthetic polymer produced by the Fischer-Tropsch reaction. It is suggested that the meteoritic polymer was also produced by surface catalysis.

  12. A Quantitative NMR Analysis of Phosphorus in Carbonaceous and Ordinary Chondrites

    Science.gov (United States)

    Pasek, M. A.; Smith, V. D.; Lauretta, D. S.

    2004-01-01

    Phosphorus is important in a number of biochemical molecules, from DNA to ATP. Early life may have depended on meteorites as a primary source of phosphorus as simple dissolution of crustal apatite may not produce the necessary concentration of phosphate. Phosphorus is found in several mineral phases in meteorites. Apatite and other Ca- and Mg phosphate minerals tend to be the dominant phosphorus reservoir in stony meteorites, whereas in more iron-rich or reduced meteorites, the phosphide minerals schreibersite, (Fe, Ni)3P, and perryite, (Ni, Fe)5(Si, P)2 are dominant. However, in CM chondrites that have experienced significant aqueous alteration, phosphorus has been detected in more exotic molecules. A series of phosphonic acids including methyl-, ethyl-, propyl- and butyl- phosphonic acids were observed by GC-MS in Murchison. Phosphorian sulfides are in Murchison and Murray. NMR spectrometry is capable of detecting multiple substances with one experiment, is non-destructive, and potentially quantitative, as discussed below. Despite these advantages, NMR spectrometry is infrequently applied to meteoritic studies due in large part to a lack of applicability to many compounds and the relatively high limit of detection requirements. Carbon-13 solid-state NMR has been applied to macromolecular carbon in Murchison. P-31 NMR has many advantages over aqueous carbon-13 NMR spectrometry. P-31 is the only isotope of phosphorus, and P-31 gives a signal approximately twice as strong as C-13. These two factors together with the relative abundances of carbon and phosphorus imply that phosphorus should give a signal approximately 20 as strong as carbon in a given sample. A discussion on the preparation of the quantitative standard and NMR studies are presented

  13. Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite.

    Science.gov (United States)

    Lin, Yangting; Guan, Yunbin; Leshin, Laurie A; Ouyang, Ziyuan; Wang, Daode

    2005-02-01

    Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium- and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine/sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred (36Cl/35Cl)o ratios of the sodalite are approximately 5 x 10(-6). Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26Al-26Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of (36Cl/35Cl)o > or = 1.6 x 10(-4) at the time when calcium- and aluminum-rich inclusions formed. This discovery supports a supernova origin of short-lived nuclides [Cameron, A. G. W., Hoeflich, P., Myers, P. C. & Clayton, D. D. (1995) Astrophys. J. 447, L53; Wasserburg, G. J., Gallino, R. & Busso, M. (1998) Astrophys. J. 500, L189-L193], but presents a serious challenge for local irradiation models [Shu, F. H., Shang, H., Glassgold, A. E. & Lee, T. (1997) Science 277, 1475-1479; Gounelle, M., Shu, F. H., Shang, H., Glassgold, A. E., Rehm, K. E. & Lee, T. (2001) Astrophys. J. 548, 1051-1070]. Furthermore, the short-lived 36Cl may serve as a unique fine-scale chronometer for volatile-rock interaction in the early solar system because of its close association with aqueous and/or anhydrous alteration processes. PMID:15671168

  14. Aqueous alteration of chondrules from the Murchison CM carbonaceous chondrite: Replacement, pore filling, and the genesis of polyhedral serpentine

    Science.gov (United States)

    Lee, M. R.; Lindgren, P.

    2016-04-01

    Forsterite and clinoenstatite in type IAB chondrules from the Murchison CM carbonaceous chondrite have been partially serpentinized, and the mechanisms of their alteration reveal crystallographic and microstructural controls on the reaction of silicate minerals with parent body aqueous solutions. Grains of forsterite were altered in two stages. Narrow veinlets of Fe-rich serpentine formed first and by the filling of sheet pores. Most of these pores were oriented parallel to (010) and (001) and had been produced by earlier fracturing and/or congruent dissolution. In the second stage, the subset of veinlets that were oriented parallel to (001) was widened accompanying the replacement of forsterite by Mg-Fe serpentine. This reaction proceeded most rapidly parallel to [001], and crystallographic controls on the trajectory of retreating vein walls created fine-scale serrations. Murchison clinoenstatite grains have a skeletal appearance due to the presence of abundant veinlets and patches of phyllosilicate. Two alteration stages can again be recognized, with initial water-mineral interaction producing tochilinite-rich veinlets by the filling of (001)-parallel contraction cracks. Pores then formed by congruent dissolution that was guided principally by orthopyroxene lamellae, and they were subsequently filled by submicrometer-sized crystals of polyhedral serpentine. This finding that Murchison forsterite and clinoenstatite grains have been altered demonstrates that aqueous processing of magnesium silicate minerals started much earlier in CM parent body history than previously believed. Our results also show that the occurrence of polyhedral serpentine can be used to locate former pore spaces within the parent body.

  15. Aqueous alteration of chondrules from the Murchison CM carbonaceous chondrite: Replacement, pore filling, and the genesis of polyhedral serpentine

    Science.gov (United States)

    Lee, M. R.; Lindgren, P.

    2016-06-01

    Forsterite and clinoenstatite in type IAB chondrules from the Murchison CM carbonaceous chondrite have been partially serpentinized, and the mechanisms of their alteration reveal crystallographic and microstructural controls on the reaction of silicate minerals with parent body aqueous solutions. Grains of forsterite were altered in two stages. Narrow veinlets of Fe-rich serpentine formed first and by the filling of sheet pores. Most of these pores were oriented parallel to (010) and (001) and had been produced by earlier fracturing and/or congruent dissolution. In the second stage, the subset of veinlets that were oriented parallel to (001) was widened accompanying the replacement of forsterite by Mg-Fe serpentine. This reaction proceeded most rapidly parallel to [001], and crystallographic controls on the trajectory of retreating vein walls created fine-scale serrations. Murchison clinoenstatite grains have a skeletal appearance due to the presence of abundant veinlets and patches of phyllosilicate. Two alteration stages can again be recognized, with initial water-mineral interaction producing tochilinite-rich veinlets by the filling of (001)-parallel contraction cracks. Pores then formed by congruent dissolution that was guided principally by orthopyroxene lamellae, and they were subsequently filled by submicrometer-sized crystals of polyhedral serpentine. This finding that Murchison forsterite and clinoenstatite grains have been altered demonstrates that aqueous processing of magnesium silicate minerals started much earlier in CM parent body history than previously believed. Our results also show that the occurrence of polyhedral serpentine can be used to locate former pore spaces within the parent body.

  16. Hydrogen and carbon isotopic ratios of polycyclic aromatic compounds in two CM2 carbonaceous chondrites and implications for prebiotic organic synthesis

    Science.gov (United States)

    Huang, Yongsong; Aponte, José C.; Zhao, Jiaju; Tarozo, Rafael; Hallmann, Christian

    2015-09-01

    Study of meteoritic organic compounds offers a unique opportunity to understand the origins of the organic matter in the early Solar System. Meteoritic polycyclic aromatic hydrocarbons (PAHs) and heteropolycyclic aromatic compounds (HACs) have been studied for over fifty years, however; their hydrogen stable isotopic ratios (δD) have never been reported. Compound-specific δD measurements of PAHs and HACs are important, in part because the carbon isotopic ratios (δ13C) of various meteoritic PAHs cannot be readily distinguished from their terrestrial counterparts and it is difficult to rule out terrestrial contamination based on carbon isotopic ratios alone. In this study, we have extracted and identified more than sixty PAHs and HACs present in two CM2 carbonaceous chondrites Murchison and LON 94101. Their carbon and hydrogen stable isotopic ratios (δ13C and δD) were measured and used to discuss about their synthetic environments and formation mechanisms. The concentration of aromatic compounds is ∼30% higher in Murchison than in the Antarctic meteorite LON 94101, but both samples contained similar suites of PAHs and HACs. All PAHs and HACs found exhibited positive δD values (up to 1100‰) consistent with an extraterrestrial origin, indicating the relatively low δ13C values are indeed an inherent feature of the meteoritic aromatic compounds. The hydrogen isotopic data suggest aromatic compounds in carbonaceous chondrites were mainly formed in the cold interstellar environments. Molecular level variations in hydrogen and carbon isotopic values offer new insights to the formation pathways for the aromatic compounds in carbonaceous chondrites.

  17. Extremely rapid cooling of a carbonaceous-chondrite chondrule containing very 16O-rich olivine and a 26Mg-excess

    Science.gov (United States)

    Yurimoto, Hisayoshi; Wasson, John T.

    2002-12-01

    We describe a phenocryst in a CO-chondrite type-II chondrule that we infer to have formed by melting an amoeboid olivine aggregate (AOA). This magnesian olivine phenocryst has an extremely 16O-rich composition Δ 17O (=δ 17O - 0.52 · δ 18O) = -23‰. It is present in one of the most pristine carbonaceous chondrites, the CO3.0 chondrite Yamato 81020. The bulk of the chondrule has a very different Δ 17O of -1‰, thus the Δ 17O range within this single chondrule is 22‰, the largest range encountered in a chondrule. We interpret the O isotopic and Fe-Mg distributions to indicate that a fine-grained AOA assemblage was incompletely melted during the flash melting that formed the chondrule. Some Fe-Mg exchange but negligible O-isotopic exchange occurred between its core and the remainder of the chondrule. A diffusional model to account for the observed Fe-Mg and O-isotopic exchange yields a cooling rate of 10 5 to 10 6 K hr -1. This estimate is much higher than the cooling rates of 10 1 to 10 3 K hr -1 inferred from furnace simulations of type-II chondrule textures (e.g. Lofgren, 1996); however, our cooling-rate applies to higher temperatures (near 1900 K) than are modeled by the crystal-growth based cooling rates. We observed a low 26Al/ 27Al initial ratio ((4.6 ± 3.0) · 10 -6) in the chondrule mesostasis, a value similar to those in ordinary chondrites (Kita et al., 2000). If the 26Al/ 27Al system is a good chronometer, then chondrule I formed about 2 Ma after the formation of refractory inclusions.

  18. Organic Analysis in Miller Range 090657 and Buckley Island 10933 CR2 Chondrites: Part 1 In-Situ Observation of Carbonaceous Material

    Science.gov (United States)

    Cao, T.; Nakamura-Messenger, K.; Berger, E. L.; Burton, A. S.; Messenger, S.; Clemett, S. J.

    2016-01-01

    Primitive carbonaceous chondrites contain a wide variety of organic material, ranging from soluble discrete molecules to insoluble unstructured kerogen-like component as well as structured nano-globules of macromolecular carbon. The relationship between the soluble organic molecules, macromolecular organic material, and host minerals are poorly understood. Due to the differences in extractability of soluble and insoluble organic materials, the analysis methods for each differ and are often performed independently. The combination of soluble and insoluble analyses, when performed concurrently, can provide a wider understanding on spatial distribution, and elemental, structural and isotopic composition of organic material in primitive meteorites. Furthermore, they can provide broader perspective on how extraterrestrial organic ma-terials potentially contributed to the synthesis of life's essential compounds such as amino acids, sugar acids, activated phosphates and nucleobases.

  19. SNOW COVER OF THE CENTRAL ANTARCTICA (VOSTOK STATION AS AN IDEAL NATURAL TABLET FOR COSMIC DUST COLLECTION: PRELIMINARY RESULTS ON THE IDENTIFICATION OF MICROMETEORITES OF CARBONACEOUS CHONDRITE TYPE

    Directory of Open Access Journals (Sweden)

    E. S. Bulat

    2012-01-01

    Full Text Available During the 2010/11 season nearby the Vostok station the 56th Russian Antarctic Expedition has collected surface snow in a big amount from a 3 m deep pit using 15 220 L vol. containers (about 70 kg snow each. Snow melting and processing by ultra-centrifugation was performed in a clean (class 10 000 and 100 laboratory. Total dust concentrations were not exceeded 37.4 mkg per liter with particle dispersal mode around 2.5 mkm. To analyze the elemental composition of fine dust particles aimed to reveal Antarctic micrometeorites (AMM two electron microscopy devices equipped with different micro-beams were implemented. As a preliminary result, three particles (of 107 analyzed featured by Mg content clearly dominated over Al along with Si and Fe as major elements (a feature of carbonaceous chondrites were observed. By this the Vostok AMM CS11 collection was established. The occurrence of given particles was averaged 2.8% – the factual value obtained for the first time for chondritic type AMM at Vostok which should be considered as the lowest estimate for all other families of AMM. Given the reference profile of total dust content in East Antarctic snow during Holocene (18 mkg/kg the MM deposition in Antarctica was quantified for the first time – 14 tons per day for carbonaceous chondrites for the Vostok AMM CS11 collection and up to 245 tons per day for all MM types for the Concordia AMM DC02 collection. The results obtained allowed to prove that snow cover (ice sheet in total of Central East Antarctica is the best spot (most clean of other natural locations and always below 0 ºC for collecting native MM deposited on the Earth during the last million years and could be useful in deciphering the origin and evolution of solid matter in our Solar System and its effects on Earth-bound biogeochemical and geophysical processes including the life origin. The farther analyses of the Vostok AMMs are in a progress.

  20. An ion probe study of the sulphur isotopic composition of Fe-Ni sulphides in CM carbonaceous chondrites

    OpenAIRE

    Bullock, E. S.; McKeegan, K. D.; Gounelle, M.; Grady, M. M.; Russell, S.S

    2004-01-01

    From the Introduction: The CM chondrites have endured variable degrees of aqueous alteration [1] which has changed their original mineralogy. A detailed study of the petrology and mineralogy of the sulphides in a suite of increasingly aqueously altered CMs, combined with sulphur isotope data measured in situ, can provide clues as to whether differences in the CM group are a result of different degrees of aqueous alteration, or whether they are the result of nebular heterogeneity.

  1. Olivine in terminal particles of Stardust aerogel tracks and analogous grains in chondrite matrix

    Science.gov (United States)

    Frank, David R.; Zolensky, Michael E.; Le, Loan

    2014-10-01

    The dearth of both major and minor element analyses of anhydrous silicate phases in chondrite matrix has thus far hindered their comparison to the Wild 2 samples. We present 68 analyses of olivine (Fa0-97) in the coarse-grained terminal particles of Stardust aerogel tracks and a comprehensive dataset (>103 analyses) of analogous olivine grains (5-30 μm) isolated in CI, CM, CR, CH, CO, CV3-oxidized, CV3-reduced, C3-ungrouped (Acfer 094 and Ningqiang), L/LL 3.0-4, EH3, and Kakangari chondrite matrix. These compositions reveal that Wild 2 likely accreted a diverse assortment of material that was radially transported from various carbonaceous and ordinary chondrite-forming regions. The Wild 2 olivine includes amoeboid olivine aggregates (AOAs), refractory forsterite, type I and type II chondrule fragments and/or microchondrules, and rare relict grain compositions. In addition, we have identified one terminal particle that has no known compositional analog in the meteorite record and may be a signature of low-temperature, aqueous processing in the Kuiper Belt. The generally low Cr content of FeO-rich olivine in the Stardust samples indicates that they underwent mild thermal metamorphism, akin to a petrologic grade of 3.05-3.15.

  2. Search for Fluid Inclusions in a Carbonaceous Chondrite Using a New X-Ray Micro-Tomography Technique Combined with FIB Sampling

    Science.gov (United States)

    Tsuchiyama, A.; Miyake, A.; Zolensky, M. E.; Uesugi, K.; Nakano, T.; Takeuchi, A.; Suzuki, Y.; Yoshida, K.

    2014-01-01

    Early solar system aqueous fluids are preserved in some H chondrites as aqueous fluid inclusions in halite (e.g., [1]). Although potential fluid inclusions are also expected in carbonaceous chondrites [2], they have not been surely confirmed. In order to search for these fluid inclusions, we have developped a new X-ray micro-tomography technique combined with FIB sampling and applied this techniqu to a carbanaceous chondrite. Experimental: A polished thin section of Sutter's Mill meteorite (CM) was observed with an optical microscope and FE-SEM (JEOL 7001F) for chosing mineral grains of carbonates (mainly calcite) and sulfides (FeS and ZnS) 20-50 microns in typical size, which may have aqueous fluid inclusions. Then, a "house" similar to a cube with a roof (20-30 microns in size) is sampled from the mineral grain by using FIB (FEI Quanta 200 3DS). Then, the house was atached to a thin W-needle by FIB and imaged by a SR-based imaging microtomography system with a Fresnel zone plate at beamline BL47XU, SPring-8, Japan. One sample was imaged at two X-ray energies, 7 and 8 keV, to identify mineral phases (dual-enegy microtomography: [3]). The size of voxel (pixel in 3D) was 50-80 nm, which gave the effective spatial resolution of approx. 200 nm. A terrestrial quartz sample with an aqueous fluid inclusion with a bubble was also examined as a test sample by the same method. Results and discussion: A fluid inclusion of 5-8 microns in quartz was clearly identified in a CT image. A bubble of approx. 4 microns was also identified as refraction contrast although the X-ray absorption difference between fluid and bubble is small. Volumes of the fluid and bubble were obtained from the 3D CT images. Fourteen grains of calcite, two grains of iron sulfide and one grain of (Zn,Fe)S were examined. Ten calcite, one iron sulfide and one (Zn,Fe)S grains have inclusions >1 micron in size (the maximum: approx. 5 microns). The shapes are spherical or irregular. Tiny inclusions (<1 micron

  3. Elephant Moraine 96029, a very mildly aqueously altered and heated CM carbonaceous chondrite: Implications for the drivers of parent body processing

    Science.gov (United States)

    Lee, Martin R.; Lindgren, Paula; King, Ashley J.; Greenwood, Richard C.; Franchi, Ian A.; Sparkes, Robert

    2016-08-01

    Elephant Moraine (EET) 96029 is a CM carbonaceous chondrite regolith breccia with evidence for unusually mild aqueous alteration, a later phase of heating and terrestrial weathering. The presence of phyllosilicates and carbonates within chondrules and the fine-grained matrix indicates that this meteorite was aqueously altered in its parent body. Features showing that water-mediated processing was arrested at a very early stage include a matrix with a low magnesium/iron ratio, chondrules whose mesostasis contains glass and/or quench crystallites, and a gehlenite-bearing calcium- and aluminium-rich inclusion. EET 96029 is also rich in Fe,Ni metal relative to other CM chondrites, and more was present prior to its partial replacement by goethite during Antarctic weathering. In combination, these properties indicate that EET 96029 is one of the least aqueously altered CMs yet described (CM2.7) and so provides new insights into the original composition of its parent body. Following aqueous alteration, and whilst still in the parent body regolith, the meteorite was heated to ∼400-600 °C by impacts or solar radiation. Heating led to the amorphisation and dehydroxylation of serpentine, replacement of tochilinite by magnetite, loss of sulphur from the matrix, and modification to the structure of organic matter that includes organic nanoglobules. Significant differences between samples in oxygen isotope compositions, and water/hydroxyl contents, suggests that the meteorite contains lithologies that have undergone different intensities of heating. EET 96029 may be more representative of the true nature of parent body regoliths than many other CM meteorites, and as such can help interpret results from the forthcoming missions to study and return samples from C-complex asteroids.

  4. Whole‐rock 26Al‐26Mg systematics of amoeboid olivine aggregates from the oxidized CV3 carbonaceous chondrite Allende

    DEFF Research Database (Denmark)

    Olsen, Mia Bjørg Stolberg; Krot, Alexander N.; Larsen, Kirsten K.;

    2011-01-01

    Abstract– We report on mineralogy, petrography, and whole-rock 26Al-26Mg systematics of eight amoeboid olivine aggregates (AOAs) from the oxidized CV chondrite Allende. The AOAs consist of forsteritic olivine, opaque nodules, and variable amounts of Ca,Al-rich inclusions (CAIs) of different types...... metasomatic alteration. Thus, the 26Al-26Mg isotope systematics of Allende CAIs and AOAs are disturbed by parent body alteration processes, and may not be suitable for high-precision chronology of the early solar system events and processes....... by ferroan olivine. The AOAs are surrounded by fine-grained, matrix-like rims composed mainly of ferroan olivine and by a discontinuous layer of Ca,Fe-rich silicates. These observations indicate that AOAs experienced in situ elemental open-system iron-alkali-halogen metasomatic alteration during...... et al. (2008). In contrast, whole-rock 26Al-26Mg isotope systematics of CAIs and AOAs from the reduced CV chondrite Efremovka define a single isochron with a slope of (5.25± 0.01) × 10−5 (Larsen et al. 2011). We infer that the excesses in 26Mg* present in Allende AOAs are due to their late-stage open-system...

  5. Whole-rock Al-Mg systematics of amoeboid olivine aggregates from the oxidized CV3 carbonaceous chondrite Allende

    DEFF Research Database (Denmark)

    Olsen, M.B.; Krot, A.N.; Larsen, Kirsten Kolbjørn;

    2011-01-01

    We report on mineralogy, petrography, and whole-rock Al- Mg systematics of eight amoeboid olivine aggregates (AOAs) from the oxidized CV chondrite Allende. The AOAs consist of forsteritic olivine, opaque nodules, and variable amounts of Ca,Al-rich inclusions (CAIs) of different types, and show ev....... Thus, the Al- Mg isotope systematics of Allende CAIs and AOAs are disturbed by parent body alteration processes, and may not be suitable for high-precision chronology of the early solar system events and processes. © The Meteoritical Society, 2011....... olivine. The AOAs are surrounded by fine-grained, matrix-like rims composed mainly of ferroan olivine and by a discontinuous layer of Ca,Fe-rich silicates. These observations indicate that AOAs experienced in situ elemental open-system iron-alkali-halogen metasomatic alteration during which Fe, Na, Cl...... contrast, whole-rock Al- Mg isotope systematics of CAIs and AOAs from the reduced CV chondrite Efremovka define a single isochron with a slope of (5.25±0.01)×10 (Larsen et al. 2011). We infer that the excesses in Mg present in Allende AOAs are due to their late-stage open-system metasomatic alteration...

  6. Identification of silicate and carbonaceous presolar grains by SIMS in the type-3 enstatite chondrite ALHA81189

    International Nuclear Information System (INIS)

    An isotope ratio imaging technique using the HokuDai isotope microscope system has been applied to in situ survey for presolar grains in the type-3 enstatite chondrite ALHA81189. Rastered and static ion beam were used for primary beam. Lateral resolution of the isotope image was achieved to be 0.4 μm for static ion beam mode and to be 0.6 μm for rastered ion beam mode. As a result, the abundances of presolar grains are 150-200% larger under the static ion beam mode than under the rastered ion beam mode. Development of image processing introducing isotopography of 32S-, 24Mg16O- and 56Fe- succeeded to increase efficiency of presolar grain characterization. Using the static ion beam and introducing appropriate isotopography were very useful methods of in situ characterization of presolar grains in meteorites

  7. The case for vestiges of early solar system biota in carbonaceous chondrites: petroleum geochemical snapshots and possible future petroleum prospects on Mars expedition

    Science.gov (United States)

    Mukhopadhyay, Prasanta K.; Mossman, David J.; Ehrman, James M.

    2007-09-01

    This research documents the analysis and interpretation of selected Carbonaceous Chondrites (CC) including Murchison, Allende, NWA 3003, Dhofar 735, Orgueil, Tagish Lake and Vigarano using organic petrology, scanning electron microscopy, and petroleum geochemistry. The kerogen microstructures and bitumen within CCs closely resemble remnant 2.5 Ga terrestrial microbial-like structures and their biodegraded components and solid bitumen. In both instances, organoclasts are associated with framboidal iron sulfides or oxides and clay-like minerals. The organic-rich kerogens within three CCs (especially Murchison) might have served as petroleum source rocks for the early generation of hydrocarbons. The maturity varies between 0.7% (Orgueil) and 1.24% (Murchison), to 5.1 % Ro (Vigarano) with predicted maturation temperatures of 100° to 475°C. Geochemical analysis of selected CCs (Murchison, Orgueil, and Tagish Lake) reveal the organic richness and the presence of low molecular weight n-alkanes (C 10 to C 20), complex cyclo-and isoalkanes, nonhydrocarbons, elemental sulfur with abundant aromatic compounds, most of them similar to bacterial and algal derived petroleum products. Apart from the concept of panspermia, the data highlights that three CCs sustained a formation temperature (oil biomarkers. Therefore, the authors propose a model of a "universal unconventional petroleum system", which implies a prospect of oil and gas within the Martian environment and elsewhere within the Solar System.

  8. Formation of replicating saponite from a gel in the presence of oxalate: implications for the formation of clay minerals in carbonaceous chondrites and the origin of life

    Science.gov (United States)

    Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D.; Sears, S. Kelly; Hesse, Reinhard; Vali, Hojatollah

    2012-01-01

    The potential role of clay minerals in the abiotic origin of life has been the subject of ongoing debate for the past several decades. At issue are the clay minerals found in a class of meteorites known as carbonaceous chondrites. These clay minerals are the product of aqueous alteration of anhydrous mineral phases, such as olivine and orthopyroxene, that are often present in the chondrules. Moreover, there is a strong correlation in the occurrence of clay minerals and the presence of polar organic molecules. It has been shown in laboratory experiments at low temperature and ambient pressure that polar organic molecules, such as the oxalate found in meteorites, can catalyze the crystallization of clay minerals. In this study, we show that oxalate is a robust catalyst in the crystallization of saponite, an Al- and Mg-rich, trioctahedral 2:1 layer silicate, from a silicate gel at 60°C and ambient pressure. High-resolution transmission electron microscopy analysis of the saponite treated with octadecylammonium (n(C)=18) cations revealed the presence of 2:1 layer structures that have variable interlayer charge. The crystallization of these differently charged 2:1 layer silicates most likely occurred independently. The fact that 2:1 layer silicates with variable charge formed in the same gel has implications for our understanding of the origin of life, as these 2:1 clay minerals most likely replicate by a mechanism of template-catalyzed polymerization and transmit the charge distribution from layer to layer. If polar organic molecules like oxalate can catalyze the formation of clay-mineral crystals, which in turn promote clay microenvironments and provide abundant adsorption sites for other organic molecules present in solution, the interaction among these adsorbed molecules could lead to the polymerization of more complex organic molecules like RNA from nucleotides on early Earth.

  9. Carbon, nitrogen, magnesium, silicon, and titanium isotopic compositions of single interstellar silicon carbide grains from the Murchison carbonaceous chondrite

    Science.gov (United States)

    Hoppe, Peter; Amari, Sachiko; Zinner, Ernst; Ireland, Trevor; Lewis, Roy S.

    1994-01-01

    Seven hundred and twenty SiC grains from the Murchison CM2 chondrite, ranging in size from 1 to 10 micrometers, were analyzed by ion microprobe mass spectrometry for their C-isotopic compositions. Subsets of the grains were also analyzed for N (450 grains), Si (183 grains), Mg (179 grains), and Ti (28 grains) isotopes. These results are compared with previous measurements on 41 larger SiC grains (up to 15 x 26 micrometers) from a different sample of Murchison analyzed by Virag et al. (1992) and Ireland, Zinner, & Amari (1991a). All grains of the present study are isotopically anomalous with C-12/C-13 ratios ranging from 0.022 to 28.4 x solar, N-14/N-15 ratios from 0.046 to 30 x solar, Si-29/Si-28 from 0.54 to 1.20 x solar, Si-30/Si-28 from 0.42 to 1.14 x solar, Ti-49/Ti-48 from 0.96 to 1.95 x solar, and Ti-50/Ti-48 from 0.94 to 1.39 x solar. Many grains have large Mg-26 excesses from the decay of Al-26 with inferred Al-26/Al-27 ratios ranging up to 0.61, or 12,200 x the ratio of 5 x 10(exp -5) inferred for the early solar system. Several groups can be distinguished among the SiC grains. Most of the grains have C-13 and N-14 excesses, and their Si isotopic compositions (mostly excesses in Si-29 and Si-30) plot close to a slope 1.34 line on a Delta Si-29/Si-28 versus Delta Si-30/Si-28 three-isotope plot. Grains with small C-12/C-13 ratios (less than 10) tend to have smaller or no N-14 excesses and high Al-26/Al-27 ratios (up to 0.01). Grains with C-12/C-13 greater than 150 fall into two groups: grains X have N-15 excesses and Si-29 and Si-30 deficits and the highest (0.1 to 0.6) Al-26/Al-27 ratios; grains Y have N-14 excesses and plot on a slope 0.35 line on a Si three-isotope plot. In addition, large SiC grains of the Virag et al. (1992) study fall into three-distinct clusters according to their C-, Si-, and Ti-isotopic compositions. The isotopic diversity of the grains and the clustering of their isotopic compositions imply distinct and multiple stellar sources

  10. Formation of insoluble organic matter in type-1 and -2 chondrites: Radiolytic or thermal processes?

    Science.gov (United States)

    Quirico, E.; Orthous-Daunay, F.; Beck, P.; Bonal, L.; Brunetto, R.; Dartois, E.; Pino, T.; Montagnac, G.; Rouzaud, J.; Engrand, C.; Duprat, J.

    2014-07-01

    Insoluble organic matter (IOM) extracted from primitive chondrites comes in the form of a polyaromatic solid with a structure and composition resembling that of terrestrial kerogens. It bears large D/H and ^{15}N/^{14}N isotopic ratios that point to a formation in a cold environment and ion-molecule reactions. However, the nature of the chemical and physical processes that led to its formation is still actively discussed: formation in the parent body by slight thermal metamorphism [1], inheritance from interstellar medium [2], or formation in the upper layer of the protosolar disk [3]. Post-accretional evolution of organic matter has also emerged as a critical issue, as it may disturb or even obscure pre-accretional information. In type 1 and 2 chondrites, evidence of short duration thermal heating of OM has been found using a variety of techniques [4]. In order to unravel pre-accretional from post-accretional processes, we have performed a survey of the composition and structure of IOM on a series of 27 CR, CM, CI, and ungrouped C2 carbonaceous chondrites (Tagish Lake, Bells, Essebi, Acfer 094) using infrared and multi-wavelength Raman micro-spectroscopy (244-, 514-, and 785-nm laser excitations [5]). Our results show that chondritic IOM from PCA 91008 (CM2), WIS 91600 (CM2), QUE 93005 (CM2), Tagish Lake (C2 ungrouped), and possibly Cold Bokkeveld (CM2) has been subjected to the past action of short-duration thermal metamorphism, presumably triggered by impacts. The IOM in most of the CM chondrites that experienced moderate to heavy aqueous alteration may have been slightly modified by collision-induced heating. Even IOM from chondrites that escaped significant thermal metamorphism (e.g., the most primitive CR chondrites) displays Raman characteristics consistent with a formation by thermal processing. This process may have happened either in the protosolar disk or in the parent body. However, an alternative energetic process to thermal heating is ion irradiation

  11. Chemical analysis of organic molecules in carbonaceous meteorites

    NARCIS (Netherlands)

    Torrao Pinto Martins, Zita Carla

    2007-01-01

    Meteorites are extraterrestrial objects that survive the passage through the Earth’s atmosphere and impact the Earth's surface. They can be divided into several classes, the carbonaceous chondrites being one of them. Carbonaceous chondrites are the oldest and best preserved meteorites and contain a

  12. Ordinary chondritic micrometeorites from the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.; Rudraswami, N.G.; Babu, E.V.S.S.K.; VijayaKumar, T.

    of ordinary chondrites (L3, Semarkona) have been reported (Jones, 1996). In addition to dusty metal in chondrules, Rambaldi and Wasson (1982) also observed minor orthopyroxene and Ca, Al-rich glass within the chondrules. Boland and Duba (1981) produced Ni...-Ni metal etc. They suggested carbonaceous chondritic precursors for a majority of the relict grain-bearing particles, a few could also be from ordinary chondrites and none from achondrites or mesosiderites. However, subsequent investigations (e...

  13. The Magnetization of Carbonaceous Meteorites

    Science.gov (United States)

    Herndon, James Herndon

    1974-01-01

    Alternating field demagnetization experiments have been conducted on representative samples of the carbonaceous meteorites (carbonaceous chondrites and ureilites). The results indicate that many, if not all, of these meteorites possess an intense and stable magnetic moment of extraterrestrial origin. Thermomagnetic analyses have been conducted on samples of all known carbonaceous meteorites. In addition to yielding quantitative magnetite estimates, these studies indicate the presence of a thermally unstable component, troilite, which reacts with gaseous oxygen to form magnetite. It is proposed that the magnetite found in some carbonaceous chondrites resulted from the oxidation of troilite during the early history of the solar system. The formation of pyrrhotite is expected as a natural consequence of magnetite formation via this reaction. Consideration is given to the implications of magnetite formation on paleointensity studies.

  14. Origins and Distribution of Chondritic Olivine Inferred from Wild 2 and Chondrite Matrix

    Science.gov (United States)

    Frank, D. R.; Zolensky, M. E.

    2014-01-01

    To date, only 180 particle impact tracks from Wild 2 have been extracted from the Stardust aerogel collector and even fewer have been thoroughly characterized. In order to provide a cohesive compositional dataset that can be compared to the meteorite record, we have made both major and minor element analyses (TEM/EDXS) of olivine and low-Ca pyroxene for 39 particles harvested from 26 tracks. However, the dearth of equivalent analyses for these phases in chondrite matrix hinders their comparison to the Wild 2 samples. To properly permit comparison of chondritic olivine and pyroxene to the Wild 2 samples, we have also provided a large, comprehensive EPMA dataset (greater than10(exp 3) analyses) of analogous grains (5-30 micrometers) isolated in L/LL3.0-4, CI, CM, CR, CH, CO, CV, Acfer 094, EH3, EL6, and Kakangari matrix

  15. Petrologic and oxygen isotopic study of ALH 85085-like chondrites

    Science.gov (United States)

    Prinz, M.; Weisberg, M. K.; Clayton, R. N.; Mayeda, T. K.; Ebihara, M.

    1994-07-01

    Four meteorites (PAT 91546, PCA 91328, PCA 91452, PCA 91467) petrologically similar to ALH 85085 chondrite have now been found. Previous studies of ALH 85085 showed it be a new kind of CR-related microchondrule-bearing chondrite, although one called it a sub-chondrite. The purpose of this study is to learn more about ALH 85085-like meteorites and their relationship to CR and CR-related (LEW 85332, Acfer 182, Bencubbin) chondrites. The methods used included petrology, INA bulk chemical analysis (PAT 91546, PCA 91467), and O isotopic analyses of the whole rocks and separated chondrules and dark inclusions (DIs) from PAT 91546. Since microchondrules and fragments are approximately 20 microns it was necessary to analyze composite samples for O; one was of approximately 100 chondrules, and another was of 5 DIs. Petrologically, the four meteorites are similar to ALH 85085, and there is no basis for determining if all of them, or any combinations, are paired. Mineralogically, olivine and pyroxene are highly magnesian FeNi metal generally has 3-10% Ni, and has a positive Ni-Co correlation similar to that in CR and CR-related chondrites. Refractory inclusions are similar in size to the chondrules and have the following assemblages: (1) hibonite-perovskite, (2) melilite-fassaite-forsterite, (3) grossite (Ca-dialuminate)-melilite-perovskite, (4) spinel-melilite, and (5) spinel-pyroxene aggregates. Chemically, INA analyses indicate that PAT 91546 and PCA 91467 are generally similar to ALH 85085. Oxygen isotopic analyses of the four whole-rock compositions fall along the CR mixing line as does ALH 85085; they are also close to LEW 85332, Acfer 182, and Bencubbin. This supports the concept that these are all CR-related chondrites. Even stronger support is found in the compositions of the chondrules and DIs in PAT 91546, which also plot on or near the CR line.

  16. Osmium Isotopic Compositions of Chondrites and Earth's Primitive Upper Mantle: Constraints on the Late Veneer

    Science.gov (United States)

    Walker, R. J.; Horan, M. F.; Morgan, J. W.; Meisel, T.

    2001-01-01

    The 187 Os/188 Os of carbonaceous chondrites averages approximately 2% lower than for enstatite and ordinary chondrites. The primitive upper mantle ratio for the Earth best matches that of ordinary and enstatite chondrites. Additional information is contained in the original extended abstract.

  17. Organic Chemistry of Carbonaceous Meteorites

    Science.gov (United States)

    Cronin, John R.

    2001-01-01

    Chiral and carbon-isotopic analyses of isovaline have been carried out on numerous samples of the Murchison and one sample of the Murray carbonaceous chondrite. The isovaline was found to be heterogeneous with regard to enantiomeric excess (ee) both between samples and within a single Murchison sample. L-Excesses ranging from 0 to 15% were observed. The isovaline delta(sup 13) C was found to be about +18%. No evidence was obtained suggesting terrestrial contamination in the more abundant L-enantiomer. A correlation was observed between isovaline (also alpha - aminoisobutyric acid) concentration and PCP content of five CM chondrites. It is suggested that isovaline, along with other meteoritic a-methyl amino acids with ee, are of presolar origin. The possible formation of ee in extraterrestrial amino acids by exposure to circularly polarized light or by magnetochiral photochemistry is discussed. Key words: Murchison meteorite, Murray meteorite, amino acids, isovaline, chirality, carbon isotopes, PCP.

  18. Microbeam analysis of four chondritic interplanetary dust particles for major elements, carbon and oxygen

    Science.gov (United States)

    Blanford, G. E.; Thomas, K. L.; Mckay, D. S.

    1988-01-01

    Chemical compositions determined using electron excited X-rays are reported for four interplanetary dust particles collected in the stratosphere. These analyses include measurements of carbon and oxygen abundances which are important elements in these primitive materials. Spot analyses show very heterogeneous compositions on a micrometer scale although average composition approaches that of C1 carbonaceous chondrites. While the spot analyses show intermediate compositions between cometary dust and carbonaceous chondrites, the heterogeneity more closely resembles that of comet Halley dust particles.

  19. Refractory inclusions in the Ornans C30 chondrite

    Science.gov (United States)

    Davis, A. M.

    1985-01-01

    Several types of metedorites contain unusual objects 10 micrometers to 2 centimeters across that are enriched in refractory elements such as calcium, aluminum and titanium. These objects, commonly known as refractory inclusions, are most abundant in the meteorites known as carbonaceous chondrites. The refractory inclusions that have been found in the Ornans metedorite, a member of a little-studied group of carbonaceous chondrites are described. Some refractory inclusions in Ornans resemble those found in other meteorites, while others are unlike any seen before. The unusual inclusions in Ornans contain minerals with extraordinary enrichments in highly refractory elements.

  20. Comment on "Hydrothermal preparation of analogous matrix minerals of CM carbonaceous chondrites from metal alloy particles" by Y. Peng and Y. Jing [Earth Planet. Sci. Lett. 408 (2014) 252-262

    Science.gov (United States)

    Pignatelli, Isabella; Vacher, Lionel G.; Marrocchi, Yves

    2015-10-01

    Peng and Jing (2014) recently reported the results of hydrothermal experiments designed to produce synthetic tochilinite/cronstedtite assemblages analogous to those found in the matrix of CM chondrites (Tomeoka and Buseck, 1982, 1983a, 1983b, 1985; Mackinnon and Zolensky, 1984; Zolensky and Mackinnon, 1986; Rubin et al., 2007; Bourot-Denise et al., 2010; Hewins et al., 2014; Marrocchi et al., 2014). The assemblage was obtained from an alloyed metal particle mixture of Fe, Mg, Al, Si, Cr and Ni under basic, reducing and S2--rich conditions. The hydrothermal syntheses were conducted in Teflon-lined stainless-steel autoclaves at temperature of 106-160 °C for short-duration runs and at 153 °C for long-duration runs. The phases in the assemblage were characterized by XRD and TEM, but only the analytical results of long-duration runs were reported in the article and in the Appendix as supplementary material. The phases identified were: cronstedtite and tochilinite (both present in all run products), tochilinite-cronstedtite intergrowths, polyhedral serpentine, a chrysotile-like phase, nanotube-like structures, and lizardite-like and brucite-like phases. Based on their experimental results, the authors put forward a hypothesis to explain the formation of matrix minerals in CM chondrites proposing that the precursors may be nanometer- to micrometer-sized particles of metal alloys that were altered at low temperatures by interaction with S-rich water under reducing and dynamic pressurized conditions.

  1. On the aerodynamic redistribution of chondrite components in protoplanetary disks

    CERN Document Server

    Jacquet, Emmanuel; Fromang, Sébastien

    2012-01-01

    Despite being all roughly of solar composition, primitive meteorites (chondrites) present a diversity in their chemical, isotopic and petrographic properties, and in particular a first-order dichotomy between carbonaceous and non-carbonaceous chondrites. We investigate here analytically the dynamics of their components (chondrules, refractory inclusions, metal/sulfide and matrix grains) in protoplanetary disks prior to their incorporation in chondrite parent bodies. We find the dynamics of the solids, subject to gas drag, to be essentially controlled by the "gas-solid decoupling parameter" $S\\equiv \\textrm{St}/\\alpha$, the ratio of the dimensionless stopping time to the turbulence parameter. The decoupling of the solid particles relative to the gas is significant when $S$ exceeds unity. $S$ is expected to increase with time and heliocentric distance. On the basis of (i) abundance of refractory inclusions (ii) proportion of matrix (iii) lithophile element abundances and (iv) oxygen isotopic composition of chon...

  2. CI chondrite-like clasts in the Nilpena polymict ureilite - Implications for aqueous alteration processes in CI chondrites

    Science.gov (United States)

    Brearley, Adrian J.; Prinz, Martin

    1992-01-01

    Petrographic studies of Nilpena polymict ureilite have revealed the presence of small quantities of carbonaceous chondrite matrix clasts. Detailed electron microprobe and TEM studies show that the chemistry and fine-scale mineralogy of one of these clasts is consistent with CI carbonaceous chondrite matrix. Compared to Orgeuil, the phyllosilicate, sulfide, and oxide mineralogy suggests that the Nilpena clasts may represent a less altered type of CI matrix. It is suggested that increased oxidation and aqueous alteration of Nilpena-type materials could result in the formation of the type of mineral assemblage observed in Orgueil. Increased alteration produces progressive more Mg-rich phyllosilicates and more Fe(3+)-rich iron oxides, such as ferrihydrite. As a function of increased alteration, Ca is also progressively leached from the matrix material to form carbonate veins. The depletion of Ca in CI chondrite matrices suggests the Ivuna and Alais may be intermediate in their degree of alteration to Nilpena and Orgueil.

  3. Transmission electron microscopy of an interplanetary dust particle with links to CI chondrites

    Science.gov (United States)

    Keller, Lindsay P.; Thomas, Kathie L.; Mckay, David S.

    1991-01-01

    The majority of hydrated interplanetary dust particles (IDPs) have compositions that resemble CI and CM chondrites, however, their mineralogies are most similar to the fine grained material in certain altered type-3 carbonaceous and ordinary chondrites. During the transmission electron microscope studies of hydrated IDPs, a unique particle was discovered whose mineralogy is very similar to that reported from CI chondrites. W7013F5 is the first IDP whose mineralogy and chemistry approximates that of CI chondrites. The similarity in mineralogy and mineral chemistry suggests that W7013F5 was altered under conditions similar to those that existed on the CI parent bodies.

  4. Comparative 187Re-187Os systematics of chondrites: Implications regarding early solar system processes

    Science.gov (United States)

    Walker, R.J.; Horan, M.F.; Morgan, J.W.; Becker, H.; Grossman, J.N.; Rubin, A.E.

    2002-01-01

    A suite of 47 carbonaceous, enstatite, and ordinary chondrites are examined for Re-Os isotopic systematics. There are significant differences in the 187Re/188Os and 187Os/188Os ratios of carbonaceous chondrites compared with ordinary and enstatite chondrites. The average 187Re/188Os for carbonaceous chondrites is 0.392 ?? 0.015 (excluding the CK chondrite, Karoonda), compared with 0.422 ?? 0.025 and 0.421 ?? 0.013 for ordinary and enstatite chondrites (1?? standard deviations). These ratios, recast into elemental Re/Os ratios, are as follows: 0.0814 ?? 0.0031, 0.0876 ?? 0.0052 and 0.0874 ?? 0.0027 respectively. Correspondingly, the 187Os/188Os ratios of carbonaceous chondrites average 0.1262 ?? 0.0006 (excluding Karoonda), and ordinary and enstatite chondrites average 0.1283 ?? 0.0017 and 0.1281 ?? 0.0004, respectively (1?? standard deviations). The new results indicate that the Re/Os ratios of meteorites within each group are, in general, quite uniform. The minimal overlap between the isotopic compositions of ordinary and enstatite chondrites vs. carbonaceous chondrites indicates long-term differences in Re/Os for these materials, most likely reflecting chemical fractionation early in solar system history. A majority of the chondrites do not plot within analytical uncertainties of a 4.56-Ga reference isochron. Most of the deviations from the isochron are consistent with minor, relatively recent redistribution of Re and/or Os on a scale of millimeters to centimeters. Some instances of the redistribution may be attributed to terrestrial weathering; others are most likely the result of aqueous alteration or shock events on the parent body within the past 2 Ga. The 187Os/188Os ratio of Earth's primitive upper mantle has been estimated to be 0.1296 ?? 8. If this composition was set via addition of a late veneer of planetesimals after core formation, the composition suggests the veneer was dominated by materials that had Re/Os ratios most similar to ordinary and

  5. Evidence for Impact Shock Melting in CM and CI Chondrite Regolith Samples

    Science.gov (United States)

    Zolensky, Michael; Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Komatsu, Mutsumi; Le, Loan

    2014-01-01

    C class asteroids frequently exhibit reflectance spectra consistent with thermally metamorphosed carbonaceous chondrites, or a mixture of phyllosilicate-rich material along with regions where they are absent. One particularly important example appears to be near-Earth asteroid 1999 JU3, the target of the Hayabusa II sample return mission [1], although not all spectra indicate this. In fact most spectra of 1999 JU3 are featureless, suggesting a heterogeneous regolith. Here we explore an alternative cause of dehydration of regolith of C class asteroids - impact shock melting. Impact shock melting has been proposed to explain some mineralogical characteristics of CB chondrites, but has not been considered a major process for hydrous carbonaceous chondrites. What evidence is there for significant shock melting in the very abundant CMs, or less abundant but still important CI chondrites?

  6. Mineralogy and chemistry of Rumuruti: The first meteorite fall of the new R chondrite group

    Science.gov (United States)

    Schulze, H.; Bischoff, A.; Palme, H.; Spettel, B.; Dreibus, G.; Otto, J.

    1994-03-01

    The Rumuruti meteorite shower fell in Rumuruti, Kenya, on 1934 January 28 at 10:45 p.m. Rumuruti is an olivine-rich chondritic breccia with light-dark structure. Based on the coexistence of highly recrystallized fragments and unequilibrated components, Rumuruti is classified as a type 3-6 chondrite breccia. The most abundant phase of Rumuruti is olivine (mostly Fa(approximately 39) with about 70 vol%. Feldspar (approximately 14 vol%; mainly plagioclase), Ca-pyroxene (5 vol%), pyrrhotite (4.4 vol%), and pentlandite (3.6 vol%) are major constituents. All other phases have abundances below 1 vol%, including low-Ca pyroxene, chrome spinels, phosphates (chlorapatite and whitlockite), chalcopyrite, ilemenite, tridymite, Ni-rich and Ge-containing metals, kamacite, and various particles enriched in noble metals like Pt, Ir, and Au. The chemical composition of Rumuruti is chondritic. The depletion in refractory elements (Sc, REE, etc.) and the comparatively high Mn, Na, and K contents are characteristic of ordinary chondrites and distinguish Rumuruti from carbonaceous chondrites. However, S, Se, and Zn contents in Rumuruti are significantly above the level expected for ordinary chondrites. The oxygen isotope composition of Rumuruti is high in delta O-17 (5.52%) and delta O-18 (5.07%). With Rumuruti, nine meteorites samples exist that are chemically and mineralogically very similar. These meteorites are attributed to at least eight different fall events. It is proposed in this paper to call this group R chondrites (rumurutites) after the first and only fall among these meteorites. The meteorites have a close relationship to ordinary chondrites. However, they are more oxidized than any of the existing groups of ordinary chondrites. Small, but significant differences in chemical composition and in oxygen isotopes between R chondrites and ordinary chondrites exclude formation of R chondrites from ordinary chondrites by oxidation. This implies a separate, independent R chondrite

  7. Delivery of Dark Material to Vesta via Carbonaceous Chondritic Impacts

    OpenAIRE

    Reddy, Vishnu; Corre, Lucille Le; O'Brien, David P.; Nathues, Andreas; Cloutis, Edward A.; Durda, Daniel D.; Bottke, William F.; Bhatt, Megha U.; Nesvorny, David; Buczkowski, Debra; Scully, Jennifer E. C.; Palmer, Elizabeth M.; Sierks, Holger; Mann, Paul J.; Becker, Kris J.

    2012-01-01

    NASA's Dawn spacecraft observations of asteroid (4) Vesta reveal a surface with the highest albedo and color variation of any asteroid we have observed so far. Terrains rich in low albedo dark material (DM) have been identified using Dawn Framing Camera (FC) 0.75 {\\mu}m filter images in several geologic settings: associated with impact craters (in the ejecta blanket material and/or on the crater walls and rims); as flow-like deposits or rays commonly associated with topographic highs; and as ...

  8. The Amino Acid Composition of the Sutter's Mill Carbonaceous Chondrite

    Science.gov (United States)

    Glavin, D. P.; Burton, A. S.; Elsila, J. E.; Dworkin, J. P.; Yin, Q. Z.; Cooper, G.; Jenniskens, P.

    2012-01-01

    In contrast to the Murchison meteorite which had a complex distribution of amino acids with a total C2 to Cs amino acid abundance of approx.14,000 parts-per-billion (ppb) [2], the Sutters Mill meteorite was found to be highly depleted in amino acids. Much lower abundances (approx.30 to 180 ppb) of glycine, beta-alanine, L-alanine and L-serine were detected in SM2 above procedural blank levels indicating that this meteorite sample experienced only minimal terrestrial amino acid contamination after its fall to Earth. Carbon isotope measurements will be necessary to establish the origin of glycine and beta-alanine in SM2. Other non-protein amino acids that are rare on Earth, yet commonly found in other CM meteorites such as aaminoisobutyric acid (alpha-AIB) and isovaline, were not identified in SM2. However, traces of beta-AIB (approx.1 ppb) were detected in SM2 and could be" extraterrestrial in origin. The low abundances of amino acids in the Sutter's Mill meteorite is consistent with mineralogical evidence that at least some parts of the Sutter's Mill meteorite parent body experienced extensive aqueous and/or thermal alteration.

  9. Intergrown mica and montmorillonite in the Allende carbonaceous chondrite

    Science.gov (United States)

    Tomeoka, K.; Buseck, P. R.

    1982-01-01

    High resolution transmission electron microscopy (HRTEM) observations were made of a mixture of mica and montmorillonite from fine-grained calcium, aluminum inclusions (CAI) in the Allende C3(V) meteorite. A petrographic thin section having a diameter of 4 mm contained CAI fragments ranging from less than 1 to 50 microns. The observed textural and chemical characteristics placed the inclusion in the fine-grained alkali-rich spinel aggregate category of Warks' (1979) classifications of CAIs and as type 3 in Kornacki's classifications of fine grains in Allende. Chemical analyses were performed on the phyllosilicate grains observed in the TEM scan by means of an X ray observed, and the proximity to the matrix boundary suggests a metamorphism which included aqueous alteration at a relatively low temperature.

  10. Heavily irradiated grains and neon isotope anomalies in carbonaceous chondrites

    Energy Technology Data Exchange (ETDEWEB)

    Audouze, J.; Bibring, J.P.; Dran, J.C.; Maurette, M.; Walker, R.M.

    1976-06-15

    High-voltage microscope observations of micron-sized grains extracted from a /sup 22/Ne-rich fraction of the Orgueil meteorite give strong experimental evidence for their heavy irradiation. It is further suggested that the excess of /sup 22/Ne measured in the same mineral separate can be explained by low-energy (<10 MeV) production by (p, a) reaction on /sup 25/Mg. A discussion of the astrophysical sites potentially responsible for the peculiar irradiation history of the meteoritic grains is presented. (AIP)

  11. Origin of magnetite and pyrrhotite in carbonaceous chondrites

    Science.gov (United States)

    Herndon, J. M.; Rowe, M. W.; Larson, E. E.; Watson, D. E.

    1975-01-01

    It is proposed that a substantial fraction of the magnetite, at least, resulted from the oxidation of troilite. Pyrrhotite is expected as a direct consequence of magnetite formation through this reaction. During thermomagnetic experiments on troilite, magnetite formation was observed at temperatures as low as 373 K, provided that the oxygen fugacity was held in the magnetite stability field, and that the troilite was sufficiently finely divided.

  12. Structure, composition, and location of organic matter in the enstatite chondrite Sahara 97096 (EH3)

    CERN Document Server

    Piani, Laurette; Beyssac, Olivier; Binet, Laurent; Bourot-Denise, Michèle; Derenne, Sylvie; Guillou, Corentin Le; Marrocchi, Yves; Mostefaoui, Smail; Rouzaud, Jean-Noel; Thomen, Aurelien

    2015-01-01

    The insoluble organic matter (IOM) of an unequilibrated enstatite chondrite Sahara (SAH) 97096 has been investigated using a battery of analytical techniques. As the enstatite chondrites are thought to have formed in a reduced environment at higher temperatures than carbonaceous chondrites, they constitute an interesting comparative material to test the heterogeneities of the IOM in the solar system and to constrain the processes that could affect IOM during solar system evolution. The SAH 97096 IOM is found in situ: as submicrometer grains in the network of fine-grained matrix occurring mostly around chondrules and as inclusions in metallic nodules, where the carbonaceous matter appears to be more graphitized. IOM in these two settings has very similar $\\delta^{15}N$ and $\\delta^{13}C$; this supports the idea that graphitized inclusions in metal could be formed by metal catalytic graphitization of matrix IOM. A detailed comparison between the IOM extracted from a fresh part and a terrestrially weathered part...

  13. Terminology of carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, G.N.; Nagornyi, V.G.; Ostrovskii, V.S.

    1986-07-01

    The need is discussed to standardize definition of carbonaceous material. Terms related to carbonaceous materials and their products are selected and analyzed. Diagramatic representation is given of relationships between carbonaceous materials. Carbon has two forms of structure, cubic and hexagonal, characterized by sp/sup 3/-hybrid groups of atoms forming spatial system of tetrahedral bonds. Hexagonal form of carbon is represented by natural materials such as graphite, shungite, anthracite and a number of artificial materials obtained during thermal treatment of organic substances at temperatures above carbonization temperature. 4 references.

  14. Halogens in CM Chondrites

    Science.gov (United States)

    Menard, J. M.; Caron, B.; Jambon, A.; Michel, A.; Villemant, B.

    2013-09-01

    We set up an extraction line of halogens (fluorine, chlorine) by pyrohydrolysis with 50 mg of rock. We analyzed 7 CM2 chondrites found in Antarctica and found that the Cl content of meteorites with an intact fusion crust is higher than those without.

  15. A Raman Study of Carbonates and Organic Contents in Five CM Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Bodnar, R. J.; Farley, C.; Cheung, J. C. H.

    2016-01-01

    Carbonates comprise the second most abundant class of carbon-bearing phases in carbonaceous chondrites after organic matter (approximately 2 wt.%), followed by other C-bearing phases such as diamond, silicon carbide, and graphite. Therefore, understanding the abundances of carbonates and the associated organic matter provide critical insight into the genesis of major carbonaceous components in chondritic materials. Carbonates in CM chondrites mostly occur as calcite (of varying composition) and dolomite. Properly performed, Raman spectroscopy provides a non-destructive technique for characterizing meteorite mineralogy and organic chemistry. It is sensitive to many carbonaceous phases, allows the differentiation of organic from inorganic materials, and the interpretation of their spatial distribution. Here, with the use of Raman spectroscopy, we determine the structure of the insoluble organic matter (IOM) in the matrix and carbonate phases in five CM chondrites: Jbilet Winselwan, Murchison, Nogoya, Santa Cruz, and Wisconsin Range (WIS) 91600, and interpret the relative timing of carbonate precipitation and the extent of the associated alteration events.

  16. Effect of a Routine Synchrotron X-Ray Microtomography Scan on the Amino Acid Content of the Murchison CM Chondrite

    Science.gov (United States)

    Friedrich, J. M.; Glavin, D. P.; Rivers, M. L.; Dworkin, J. P.

    2015-07-01

    We conducted experiments to examine if exposure to synchrotron radiation during a typical µCT scan causes detectable changes in the amino acid content of a carbonaceous chondrite. We found a µCT scan caused no change in the amino acid content.

  17. Weathering of Ordinary Chondrites from Algeria and Australia as a Climatic Indicator

    Science.gov (United States)

    Bland, P. A.; Berry, F. J.; Pillinger, C. T.

    1995-09-01

    Introduction: Recently it has been recognized that ordinary chondrite meteorites resident in desert regions may preserve information about the climate at the time of their arrival on Earth in the degree to which they are weathered [1], providing that a stable surface has existed at the accumulation site. We present here a comparison of ^57Fe Mossbauer spectroscopy data for additional meteorites for which terrestrial ages exist, recovered from Reg el Acfer, Algeria and the Nullarbor Region, Australia. Results and Discussion: The data presented in Fig. 1 compare abundance of ferric iron oxide/oxyhydroxide species against terrestrial age [2, 3] for ordinary chondrites from Australia (a) and Algeria (b). Even with an increased dataset for Australian meteorites (compared to that already presented [1]) the initial hypothesis remains intact i.e. meteorite weathering over time is sensitive to changes in climate. Peaks in oxidation at around 2,000, 7,000 and 23,000 years correspond to periods of speleothem formation [4] and high lake level status [5]. Similarly, a period of low oxidation between 12,000-20,000 years is mirrored in low lake level status [5] and aridity in the Nullarbor [6]. The mechanism by which meteorites may record palaeoclimatic information is given in [1]. A correlation that strengthens our case is that where data from both H and L(LL) chondrites are available (i.e. around 7,000-8,000 years) the two plots are similar, indicating a broadscale environmental effect. In contrast, the distribution for meteorites from the Acfer region appears to be more random, with no correlation between H and L(LL) data. The difference may be related to the stability of the respective accumulation surfaces. The surface of the Nullarbor appears to have been stable over the last 30,000 years [7]. The Algerian and Libyan Sahara, however, has experienced several episodes of active fluvial processes over the last 10,000 years [8] which may have profoundly effected the meteorites

  18. Organic Analysis in the Miller Range 090657 CR2 Chondrite: Part 3 C and N Isotopic Imaging

    Science.gov (United States)

    Messenger, S.; Nakamura-Messenger, K.; Elsila, J. E.; Berger, E. L.; Burton, A. S.; Clemett, S. J.; Cao, T.

    2016-01-01

    Primitive carbonaceous chondrites contain a wide variety of organic material, ranging from soluble discrete molecules to insoluble nanoglobules of macro-molecular carbon. The relationship between the soluble organic molecules, macromolecular organic material, and host minerals are poorly understood. Large H, C and N isotopic anomalies suggest some organic components formed in low-T interstellar or outer Solar System environments. The highest isotope anomalies occur in m-scale inclusions in the most primitive materials, such as cometary dust and the least altered carbonaceous chondrites. Often, the hosts of these isotopically anomalous 'hotspots' are discrete organic nanoglobules that probably formed in the outermost reaches of the protosolar disk or cold molecular cloud. Molecular and isotopic studies of meteoritic organic matter are aimed at identifying the chemical properties and formation processes of interstellar organic materials and the subsequent chemical evolutionary pathways in various Solar System environments. The combination of soluble and insoluble analyses with in situ and bulk studies provides powerful constraints on the origin and evolution of organic matter in the Solar System. Using macroscale extraction and analysis techniques as well as microscale in situ observations we have been studying both insoluble and soluble organic material in primitive astromaterial samples. Here, we present results of bulk C and N isotopic measurements and coordinated in situ C and N isotopic imaging and mineralogical and textural studies of carbonaceous materials in a Cr2 carbonaceous chondrite. In accompanying abstracts we discuss the morphology and distribution of carbonaceous components and soluble organic species of this meteorite.

  19. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation.

    Science.gov (United States)

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-01-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System. PMID:26461170

  20. The Effects of Thermal Metamorphism on the Amino Acid Content of the CI-Like Chondrite Y-86029

    Science.gov (United States)

    Burton, A. S.; Grunsfeld, S.; Glavin, D. P.; Dworkin, J. P.

    2014-01-01

    Carbonaceous chondrites con-tain a diverse suite of amino acids that varies in abundance and structural diversity depending on the degree of aqueous alteration and thermal histo-ry that the parent body experienced [1 - 3]. We recently determined the amino acid contents of several fragments of the Sutter's Mill CM2 chon-drite [4]. In contrast with most other CM2 chon-drites, the Sutter's Mill meteorites showed minimal evidence for the presence of indigenous amino acids. A notable difference between the Sutter's Mill meteorites and other CM2 chondrites are that the Sutter's Mill stones were heated to tempera-tures of 150 - 400 C [4], whereas most other CM2 chondrites do not show evidence for thermal met-amorphism [5]. Because empirical studies have shown that amino acids rapidly degrade in aqueous solutions above 150 C and the presence of miner-als accelerates this degradation [6], a plausible explanation for the lack of amino acids observed in the Sutter's Mill meteorites is that they were destroyed during metamorphic alteration. Fewer CI chondrites have been analyzed for amino acids because only a small number of these meteorites have been recovered. Nevertheless, indigenous amino acids have been reported in the CI chondrites Ivuna and Orgueil [7]. Here we report on the amino acid analysis of the CI-like chondrite, Yamato 86029 (Y-86029; sample size of 110 mg). Just as the Sutter's Mill meteorites were thermally metamporphosed CM2 chondrites, Y-86029 has experienced thermal metamorphism at higher temperatures than Orgueil and Ivuna (normal CI chondrites) experienced, possibly up to 600 C [8].

  1. Isotopic anomalies of noble gases in meteorites and their origins. III - LL-chondrites

    Science.gov (United States)

    Alaerts, L.; Lewis, R. S.; Anders, E.

    1979-01-01

    Nine LL-chondrites were studied by selective etching to characterize the noble gas components in three mineral fractions: HF-HCl-solubles, chromite and carbon. The Ne-20/Ar-36 ratio is considered, noting that chondrites of different petrologic types cannot all be derived from the same volatile rich ancestor, but must have formed over a range of temperatures, with correspondingly different volatile contents. Variations in the carbonaceous chondrite fission (CCFXe) component in LL3, LL5, and LL6 chondrites are discussed, noting that if CCFXe comes from a supernova, then its distribution in LL-chondrites requires three presolar carrier minerals of the right solubility properties, containing three different xenon components. However, if CCFXe comes from fission of a volatile superheavy element, then its decrease from LL3 to LL6 can be attributed to less complete condensation from the solar nebula. Finally, the three types of primordial xenon components which occur in different minerals of the same meteorite are described.

  2. MODIFICATION OF CARBONACEOUS ADSORBENTS WITH MANGANESE COMPOUNDS

    OpenAIRE

    Irina Ginsari; Larisa Postolachi; Vasile Rusu; Oleg Petuhov; Tatiana Goreacioc; Tudor Lupascu; Raisa Nastas

    2015-01-01

    Four series of samples containing manganese supported carbonaceous adsorbents were prepared. Obtained results reveal the importance of surface chemistry of carbonaceous adsorbents on the manganese loading.

  3. A refractory inclusion in the Kaba CV3 chondrite - Some implications for the origin of spinel-rich objects in chondrites

    Science.gov (United States)

    Fegley, B.; Post, J. E.

    1985-11-01

    The first detailed petrographic and mineralogical study of a Ca, Al-rich inclusion (CAI) from the Kaba CV3 chondrite is reported. This 'fine-grained' CAI contains abundant small, rounded, rimmed, spinel-rich objects which have important features in common with the spinel-rich objects in other carbonaceous and ordinary chondrites. These nodules are interpreted as fractionated distillation residues of primitive dust. However, the available data do not unambiguously rule out a condensation origin for at least some of these objects. Finally, the preservation of distinct diopside-hedenbergite rims on the spinel-rich bodies and the small grain size of many minerals in the CAI matrix material both suggest that the CAI accreted cool and had a relatively cool thermal history in the Kaba parent body.

  4. Clues to the origin of sulfide minerals in CI chondrites

    International Nuclear Information System (INIS)

    The dominant sulfide in Ci carbonaceous chondrites is an Fe-deficient pyrrhotite containing about 1% Ni. Alais, Ivuna and Orgueil also contain minor cubanite, CuFe2S3, and Alais minor pentlandite, (Fe, Ni)9S8. All pyrrhotites contain 39.4 +- 0.1% S; Ni contents range from 0.7 to 1.3%. The phase diagrams reveal no temperature at which the observed pentlandite-pyrrhotite assemblage is at equilibrium. Similarly, the pyrrhotite compositions alone are inconsistent with equilibrium formation from a gas of solar composition. In Xe from high-purity submilligram Orgueil pyrrhotite separates, the ratios 129Xe/132Xe are not significantly larger than those in trapped meteoritic Xe. The lack of positive evidence for extinct 129I in pyrrhotite does not permit any inferences regarding cooling rates in the early solar nebula. Tt is concluded that sulfides in CI chondrites cannot be nebular condensates formed under equilibrium conditions. Argon isotopic abundances reveal the presence of significant spallation and trapped gas components in Orgueil pyrrhotite. The Orgueil exposure age is calculated to be > approximately 10 m.y. (Auth.)

  5. Clues to the origin of sulfide minerals in CI chondrites

    Science.gov (United States)

    Kerridge, J. F.; Macdougall, J. D.; Marti, K.

    1979-01-01

    The dominant sulfide in CI carbonaceous chondrites is an Fe-deficient pyrrhotite containing about 1% Ni, Alais, Ivuna, and Orgueil also contain minor cubanite, CuFe2S3, and Alais minor pentlandite, (Fe,Ni)9S8. All pyrrhotites contain 39.4 + or - 0.1% S; Ni contents range from 0.7 to 1.3%. The phase diagrams reveal no temperature at which the observed pentlandite-pyrrhotite assemblage is at equilibrium. Similarly, the pyrrhotite composition alone are inconsistent with equilibrium formation from a gas of solar composition. In Xe from high-purity submilligram Orgueil pyrrhotite separates, the ratios Xe-129/Xe-132 are not significantly larger than those in trapped meteoritic Xe. The lack of positive evidence for extinct I-129 in pyrrhotite does not permit any inferences regarding cooling rates in the early solar nebula. It is concluded that sulfides in CI chondrites cannot be nebular condensates formed under equilibrium conditions. Argon isotopic abundances reveal the presence of significant spallation and trapped gas components in Orgueil pyrrhotite. The Orgueil exposure age is calculated to be at least about 10 m.y.

  6. Micron-scale D/H heterogeneity in chondrite matrices: a signature of the pristine solar system water?

    CERN Document Server

    Piani, Laurette; Remusat, Laurent

    2015-01-01

    Organic matter and hydrous silicates are intimately mixed in the matrix of chondrites and in-situ determination of their individual D/H ratios is therefore challenging. Nevertheless, the D/H ratio of each pure component in this mixture should yield a comprehensible signature of the origin and evolution of water and organic matter in our solar system. We measured hydrogen isotope ratios of organic and hydrous silicates in the matrices of two carbonaceous chondrites (Orgueil CI1 and Renazzo CR2) and one unequilibrated ordinary chondrite (Semarkona, LL3.0). A novel protocol was adopted, involving NanoSIMS imaging of H isotopes of monoatomatic ($H^-$) and molecular ($OH^-$) secondary ions collected at the same location. This allowed the most enriched component with respect to D to be identified in the mixture. Using this protocol, we found that in carbonaceous chondrites the isotopically homogeneous hydrous silicates are mixed with D-rich organic matter. The opposite was observed in Semarkona. Hydrous silicates i...

  7. Aqueous processing of organic compounds in carbonaceous asteroids

    Science.gov (United States)

    Trigo-Rodríguez, Josep Maria; Rimola, Albert; Martins, Zita

    2015-04-01

    There is growing evidence pointing towards a prebiotic synthesis of complex organic species in water-rich undifferentiated bodies. For instance, clays have been found to be associated with complex organic compounds (Pearson et al. 2002; Garvie & Buseck 2007; Arteaga et al. 2010), whereas theoretical calculations have studied the interaction between the organic species and surface minerals (Rimola et al., 2013) as well as surface-induced reactions (Rimola at al. 2007). Now, we are using more detailed analytical techniques to study the possible processing of organic molecules associated with the mild aqueous alteration in CR, CM and CI chondrites. To learn more about these processes we are studying carbonaceous chondrites at Ultra High-Resolution Transmission Electron Microscopy (UHR-TEM). We are particularly interested in the relationship between organics and clay minerals in carbonaceous chondrites (CCs) matrixes (Trigo-Rodríguez et al. 2014, 2015).We want to address two goals: i) identifying the chemical steps in which the organic molecules could have increased their complexity (i.e., surface interaction and catalysis); and ii) studying if the organic matter present in CCs experienced significant processing concomitant to the formation of clays and other minerals at the time in which these planetary bodies experienced aqueous alteration. Here, these two points are preliminarily explored combing experimental results with theoretical calculations based on accurate quantum mechanical methods. References Arteaga O, Canillas A, Crusats J, El-Hachemi Z, Jellison GE, Llorca J, Ribó JM (2010) Chiral biases in solids by effect of shear gradients: a speculation on the deterministic origin of biological homochirality. Orig Life Evol Biosph 40:27-40. Garvie LAJ, Buseck PR (2007) Prebiotic carbon in clays from Orgueil and Ivuna (CI) and Tagish lake (C2 ungrouped) meteorites. Meteorit Planet Sci 42:2111-2117. Pearson VK, Sephton MA, Kearsley AT, Bland AP, Franchi IA, Gilmour

  8. The Confirmation of a New Type of Chondrites and Their Cosmochemical Significance

    Institute of Scientific and Technical Information of China (English)

    侯渭

    1996-01-01

    The data available show that some Antarctic carbonaceous chondrites are similar to Cl meteorites.Tehy contain a lot of phyllosilicate aggregates and the oxygen isotopic composition of the whole-rock samples is approximate to that of C1 chondrites,so they are named after quasi-C1(Q-C1)chondrites Unlike Cl metcorites,the Q-Cl chondites possess chondrule structrue,and the compositions of hih temperature condensates(chondrule fragments,mineral grains or aggregates)show that the oxygen fugacity varied within a wide range in the surroundings where they were formed,similar to the variation range from E.H.L,LL to C group chondrites.It is inferred that the Q-C1 chondrites could be formed at the edges far from the equator in the whole asteroid region of the solar nebular disk.where the nebula was lower in density and the condensates were lower in accretion velocity,so that the hydration of chon drules and matrix occurred during the late stage of nebular condensation.The discovery of the Q-Cl chondrites and the fact that the earth and other terrestrial planets contain water indicate that at the edges far from the equator in the terrestrial reigion of the solar nebular disk,a large amount of water was incorporated into the lattice of minerals in the condensates as a result of hydration during nebular condensation,and then found its way into the interior parts of the Earth and other terrestrial planets due to accretion.

  9. Trace element geochemistry of ordinary chondrite chondrules: the type I/type II chondrule dichotomy

    CERN Document Server

    Jacquet, Emmanuel; Gounelle, Matthieu

    2015-01-01

    We report trace element concentrations of silicate phases in chondrules from LL3 ordinary chondrites Bishunpur and Semarkona. Results are similar to previously reported data for carbonaceous chondrites, with rare earth element (REE) concentrations increasing in the sequence olivine ~ 10 K/h) than type I chondrules. Appreciable Na concentrations (3-221 ppm) are measured in olivine from both chondrule types; type II chondrules seem to have behaved as closed systems, which may require chondrule formation in the vicinity of protoplanets or planetesimals. At any rate, higher solid concentrations in type II chondrule forming regions may explain the higher oxygen fugacities they record compared to type I chondrules. Type I and type II chondrules formed in different environments and the correlation between high solid concentrations and/or oxygen fugacities with rapid cooling rates is a key constraint that chondrule formation models must account for.

  10. Everyone Wins: A Mars-Impact Origin for Carbonaceous Phobos and Deimos

    Science.gov (United States)

    Fries, M.; Welzenbach, L.; Steele, A.

    2016-01-01

    Discussions of Phobos' and Deimos' origin(s) tend to feature an orthogonally opposed pair of observations: dynamical studies which favor coalescence of the moons from an orbital debris ring arising from a large impact on Mars; and reflectance spectroscopy of the moons that indicate a carbonaceous composition that is not consistent with Martian surface materials. One way to reconcile this discrepancy is to consider the option of a Mars-impact origin for Phobos and Deimos, followed by surficial decoration of carbon-rich materials by interplanetary dust particles (IDP). The moons experience a high IDP flux because of their location in Mars' gravity well. Calculations show that accreted carbon is sufficient to produce a surface with reflectance spectra resembling carbonaceous chondrites.

  11. Terrestrial microbes in martian and chondritic meteorites

    Science.gov (United States)

    Airieau, S.; Picenco, Y.; Andersen, G.

    2007-08-01

    Introduction: The best extraterrestrial analogs for microbiology are meteorites. The chemistry and mineralogy of Asteroid Belt and martian (SNC) meteorites are used as tracers of processes that took place in the early solar system. Meteoritic falls, in particular those of carbonaceous chondrites, are regarded as pristine samples of planetesimal evolution as these rocks are primitive and mostly unprocessed since the formation of the solar system 4.56 billion years ago. Yet, questions about terrestrial contamination and its effects on the meteoritic isotopic, chemical and mineral characteristics often arise. Meteorites are hosts to biological activity as soon as they are in contact with the terrestrial biosphere, like all rocks. A wide biodiversity was found in 21 chondrites and 8 martian stones, and was investigated with cell culture, microscopy techniques, PCR, and LAL photoluminetry. Some preliminary results are presented here. The sample suite included carbonaceous chondrites of types CR, CV, CK, CO, CI, and CM, from ANSMET and Falls. Past studies documented the alteration of meteorites by weathering and biological activity [1]-[4]. Unpublished observations during aqueous extraction for oxygen isotopic analysis [5], noted the formation of biofilms in water in a matter of days. In order to address the potential modification of meteoritic isotopic and chemical signatures, the culture of microbial contaminating species was initiated in 2005, and after a prolonged incubation, some of the species obtained from cell culture were analyzed in 2006. The results are preliminary, and a systematic catalog of microbial contaminants is developing very slowly due to lack of funding. Methods: The primary method was cell culture and PCR. Chondrites. Chondritic meteorite fragments were obtained by breaking stones of approximately one gram in sterile mortars. The core of the rocks, presumably less contaminated than the surface, was used for the present microbial study, and the

  12. Water transport in protoplanetary disks and the hydrogen isotopic composition of chondrites

    CERN Document Server

    Jacquet, Emmanuel

    2013-01-01

    The D/H ratios of carbonaceous chondrites, believed to reflect that of water in the inner early solar system, are intermediate between the protosolar value and that of most comets. The isotopic composition of cometary water has been accounted for by several models where the isotopic composition of water vapor evolved by isotopic exchange with hydrogen gas in the protoplanetary disk. However, the position and the wide variations of the distribution of D/H ratios in carbonaceous chondrites have yet to be explained. In this paper, we assume that the D/H composition of cometary ice was achieved in the disk building phase and model the further isotopic evolution of water in the inner disk in the classical T Tauri stage. Reaction kinetics compel isotopic exchange between water and hydrogen gas to stop at $\\sim$500 K, but equilibrated water can be transported to the snow line (and beyond) via turbulent diffusion and consequently mix with isotopically comet-like water. Under certain simplifying assumptions, we calcul...

  13. Using the Fe/Mn Ratio of FeO-Rich Olivine In WILD 2, Chondrite Matrix, and Type IIA Chondrules to Disentangle Their Histories

    Science.gov (United States)

    Frank, David R.; Le, L.; Zolensky, M. E.

    2012-01-01

    The Stardust Mission returned a large abundance of impactors from Comet 81P/Wild2 in the 5-30 m range. The preliminary examination of just a limited number of these particles showed that the collection captured abundant crystalline grains with a diverse mineralogy [1,2]. Many of these grains resemble those found in chondrite matrix and even contain fragments of chondrules and CAIs [1-3]. In particular, the olivine found in Wild 2 exhibits a wide compositional range (Fa0-97) with minor element abundances similar to the matrix olivine found in many carbonaceous chondrites (CCs) and unequilibrated ordinary chondrites (UOCs). Despite the wide distribution of Fa content, the olivine found in the matrices of CCs, UOCs, and Wild 2 can be roughly lumped into two types based solely on fayalite content. In fact, in some cases, a distinct bi-modal distribution is observed.

  14. Thermomagnetic analysis of meteorites. III - C3 and C4 chondrites

    Science.gov (United States)

    Herndon, J. M.; Rowe, M. W.; Larson, E. E.; Watson, D. E.

    1976-01-01

    Results are presented for thermomagnetic analysis in a controlled oxygen atmosphere of samples from thirteen C3 chondrites and two C4 chondrites. The examined meteorites are found to have rather diverse thermomagnetic properties, so they are placed into three groups on the basis of their thermomagnetic behavior and magnetic mineralogy: (1) those possibly containing magnetite before heating, but which display a large increase in saturation moment upon cooling to room temperature; (2) those containing magnetite as their major magnetic phase, but which show little change in saturation moment following the heating-cooling cycle; and (3) those which contain iron metal in addition to other magnetic phases. Upper limits are placed on the magnetite content of the five meteorites in group 1 by assuming that the initial saturation moment is due entirely to magnetite, and quantitative estimates of the magnetite content of the four meteorites in group 2 are determined from ambient-temperature saturation magnetization measurements. The data for the six meteorites in group 3 are discussed in terms of nickel content and troilite oxidation. It is concluded that since the magnetic and bulk mineralogies of carbonaceous chondrites are more varied and complex than indicated by whole-rock elemental analyses, the origin of such meteorites cannot be described by a simple model.

  15. Yamato 86029: Aqueously altered and thermally metamorphosed CI-like chondrite with unusual textures

    Science.gov (United States)

    Tonui, E. K.; Zolensky, M. E.; Lipschutz, M. E.; Wang, M. S.; Nakamura, T.

    2003-02-01

    We describe the petrologic and trace element characteristics of the Yamato 86029 (Y-86029) meteorite. Y-86029 is a breccia consisting of a variety of clasts, and abundant secondary minerals including coarse- and fine-grained phyllosilicates, Fe-Ni sulfides, carbonates, and magnetite. There are no chondrules, but a few anhydrous olivine-rich grains are present within a very fine-grained phyllosilicate-rich matrix. Analyses of 14 thermally mobile trace elements suggest that Y-86029 experienced moderate, open-system thermal metamorphism. Comparison with data for other heated carbonaceous chondrites suggests metamorphic temperatures of 500­600 deg C for Y-86029. This is apparent petrographically, in partial dehydration of phyllosilicates to incompletely re-crystallized olivine. This transformation appears to proceed through `intermediate' highly-disordered `poorly crystalline' phases consisting of newly formed olivine and residual desiccated phyllosilicate and their mixtures. Periclase is also present as a possible heating product of Mg-rich carbonate precursors. Y-86029 shows unusual textures rarely encountered in carbonaceous chondrites. The periclase occurs as unusually large Fe-rich clasts (300­500 μm). Fine-grained carbonates with uniform texture are also present as small (10­15 μm in diameter), rounded to sub-rounded `shells' of ankerite/siderite enclosing magnetite. These carbonates appear to have formed by low temperature aqueous alteration at specific thermal decomposition temperatures consistent with thermodynamic models of carbonate formation. The fine and uniform texture suggests crystallization from a fluid circulating in interconnected spaces throughout entire growth. One isolated aggregate in Y-86029 also consists of a mosaic of polycrystalline olivine aggregates and sulfide blebs typical of shock-induced melt re- crystallization. Except for these unusual textures, the isotopic, petrologic and chemical characteristics of Y- 86029 are quite similar

  16. Petrology and mineralogy of CK chondrites: Implications for the metamorphism of the CK chondrite parent body

    OpenAIRE

    Takaaki, Noguchi

    1993-01-01

    The petrology and mineralogy of four CK chondrites, Karoonda (CK4), Maralinga (CK4), Yamato(Y)-693(CK4), and Elephant Moraine (EET) 87507 (CK5) were investigated in detail to estimate the origin of their quite heterogeneous plagioclases and the metamorphic history of CK chondrite parent body. EPMA analyses and SEM observations revealed that plagioclases in chondrules, CAIs, and matrices in CK chondrites have different compositional variations and that plagioclases in matrices display distinct...

  17. Deducing Wild 2 Components with a Statistical Dataset of Olivine in Chondrite Matrix

    Science.gov (United States)

    Frank, D. R.; Zolensky, M. E.; Le, L.

    2012-01-01

    Introduction: A preliminary exam of the Wild 2 olivine yielded a major element distribution that is strikingly similar to those for aqueously altered carbonaceous chondrites (CI, CM, and CR) [1], in which FeO-rich olivine is preferentially altered. With evidence lacking for large-scale alteration in Wild 2, the mechanism for this apparent selectivity is poorly understood. We use a statistical approach to explain this distribution in terms of relative contributions from different chondrite forming regions. Samples and Analyses: We have made a particular effort to obtain the best possible analyses of both major and minor elements in Wild 2 olivine and the 5-30 micrometer population in chondrite matrix. Previous studies of chondrite matrix either include larger isolated grains (not found in the Wild 2 collection) or lack minor element abundances. To overcome this gap in the existing data, we have now compiled greater than 10(exp 3) EPMA analyses of matrix olivine in CI, CM, CR, CH, Kakangari, C2-ungrouped, and the least equilibrated CO, CV, LL, and EH chondrites. Also, we are acquiring TEM/EDXS analyses of the Wild 2 olivine with 500s count times, to reduce relative errors of minor elements with respect to those otherwise available. Results: Using our Wild 2 analyses and those from [2], the revised major element distribution is more similar to anhydrous IDPs than previous results, which were based on more limited statistics (see figure below). However, a large frequency peak at Fa(sub 0-1) still persists. All but one of these grains has no detectable Cr, which is dissimilar to the Fa(sub 0-1) found in the CI and CM matrices. In fact, Fa(sub 0-1) with strongly depleted Cr content is a composition that appears to be unique to Kakangari and enstatite (highly reduced) chondrites. We also note the paucity of Fa(sub greater than 58), which would typically indicate crystallization in a more oxidizing environment [3]. We conclude that, relative to the bulk of anhydrous IDPs

  18. Diversity in C-Xanes Spectra Obtained from Carbonaceous Solid Inclusions from Monahans Halite

    Science.gov (United States)

    Kebukawa, Y.; Zolensky, M. E.; Fries, M.; Kilcoyne, A. L. D.; Rahman, Z.; Cody, G. D.

    2014-01-01

    Monahans meteorite (H5) contains fluid inclusion- bearing halite (NaCl) crystals [1]. Microthermometry and Raman spectroscopy showed that the fluid in the inclusions is an aqueous brine and they were trapped near 25degC [1]. Their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism [2]. Abundant solid inclusions are also present in the halites. The solid inclusions include abundant and widely variable organics [2]. Analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction and TEM reveal that these grains include macromolecular carbon similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99-59), high- and low-Ca pyroxene, feldspars, magnetite, sulfides, lepidocrocite, carbonates, diamond, apatite and possibly the zeolite phillipsite [3]. Here we report organic analyses of these carbonaceous residues in Monahans halite using C-, N-, and O- X-ray absorption near edge structure (XANES). Samples and Methods: Approximately 100 nm-thick sections were extracted with a focused ion beam (FIB) at JSC from solid inclusions from Monahans halite. The sections were analyzed using the scanning transmission X-ray microscope (STXM) on beamline 5.3.2.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory for XANES spectroscopy. Results and Discussion: C-XANES spectra of the solid inclusions show micrometer-scale heterogeneity, indicating that the macromolecular carbon in the inclusions have complex chemical variations. C-XANES features include 284.7 eV assigned to aromatic C=C, 288.4-288.8 eV assigned to carboxyl, and 290.6 eV assigned to carbonate. The carbonyl features obtained by CXANES might have been caused by the FIB used in sample preparation. No specific N-XANES features are observed. The CXANES spectra obtained from several areas in the FIB sections include type 1&2 chondritic IOM like, type 3 chondritic IOM like, and none of the above

  19. Tin in a chondritic interplanetary dust particle

    Science.gov (United States)

    Rietmeijer, Frans J. M.

    1989-01-01

    Submicron platey Sn-rich grains are present in chondritic porous interplanetary dust particle (IDP) W7029 A and it is the second occurrence of a tin mineral in a stratospheric micrometeorite. Selected Area Electron Diffraction data for the Sn-rich grains match with Sn2O3 and Sn3O4. The oxide(s) may have formed in the solar nebula when tin metal catalytically supported reduction of CO or during flash heating on atmospheric entry of the IDP. The presence of tin is consistent with enrichments for other volatile trace elements in chondritic IDPs and may signal an emerging trend toward nonchondritic volatile element abundances in chondritic IDPs. The observation confirms small-scale mineralogical heterogeneity in fine-grained chondritic porous interplanetary dust.

  20. Evidence for Live Cl-36 in Ca-Al-rich Inclusions from the Ningqiang Carbonaceous Chondrite

    Science.gov (United States)

    Lin, Y.; Guan, Y.; Leshin, L. A.; Ouyang, Z.; Wang, D.

    2004-01-01

    The short-lived radionuclide Cl-36 decays to either Ar-36 (98.1%, beta(sup -)) or S-36 (1.9%, epsilon and beta(sup +)), with a half life of 3.01 x 10(exp 5) yr. Both the nucleosynthetic and spallation models suggest high initial Cl-36/Cl-35 ratios ((Cl-36/Cl-35)o up to approximately 10(exp -4)) in the early solar system. Previous observed excess Ar-36 in Efremovka matrix has been interpreted to represent a much lower (Cl-36/Cl-35)o ratio of approximately 1 x 10(exp -6). From the observed S-36 excesses in sodalite in calcium aluminum-rich inclusions (CAIs), we report in this study the first direct evidence of the presence of Cl-36 in primitive meteorites. The inferred (Cl-36/Cl-35)o ratios range from approximately 5 x 10(exp -6) to approximately 1 x 10(exp -5).

  1. Oxygen isotopic composition of relict olivine grains in cosmic spherules: Links to chondrules from carbonaceous chondrites

    OpenAIRE

    N.G. Rudraswami, M. Shyam Prasad, K. Nagashima, R.H. Jones

    2015-01-01

    Most olivine relict grains in cosmic spherules selected for the present study are pristine and have not been disturbed during their atmospheric entry, thereby preserving their chemical, mineralogical and isotopic compositions. In order to understand the origin of the particles, oxygen isotope compositions of relict olivine grains in twelve cosmic spherules collected from deep sea sediments of the Indian Ocean were studied using secondary ion mass spectrometry. Most of the data lie close to th...

  2. Oxygen isotopic composition of relict olivine grains in cosmic spherules: Links to chondrules from carbonaceous chondrites

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; ShyamPrasad, M.; Nagashima, K.; Jones, R.H.

    the seafloor up to 15 cm (Rudraswami et al., 2011a; 4    Rudraswami et al. 2012; Prasad et al., 2013). Close to ~3 tonnes (wet weight) of sediment were sieved on two different cruises of Akademik Aleksandr Sidorenko (a research vessel chartered... microscope, mounted in epoxy and polished to expose their internal features. Fifteen such mounts were prepared having more than a hundred spherules on a single section. For the present investigation, we selected cosmic spherules having potential relict...

  3. Structures and textures of the Murchison and Mighei carbonaceous chondrite matrices

    Science.gov (United States)

    Mackinnon, I. D. R.

    1980-01-01

    High-resolution transmission electron microscopy has confirmed earlier observations that the character of the Murchison and Mighei fine-grained matrices is complex in mineralogy and texture. Layer structure minerals occur as planar laths, rounded grains or subhedral grains, and range in size from less than 100 A to about 1 micrometer. Serpentine-type and brucite-type structures predominate in the CM matrices. The occurrence of Povlen chrysolite and a vein of disordered mixed-layer and brucite-type material cutting a large lizardite-type grain suggests that at least some of the matrix materials were formed by alteration of preexisting material.

  4. Petrographic Studies of Sulfide Assemblages in the Allende CV3 Carbonaceous Chondrite

    Science.gov (United States)

    Wetteland, Chris; Brearley, Adrian J.

    2002-01-01

    Studies of sulfides in Allende show that pyrrhotite occurs mainly within chondrules and has been partially replaced by pentlandite. Ni and Co contents of pentlandites within individual chondrules are homogeneous, but are variable between chondrules. Additional information is contained in the original extended abstract.

  5. Origin of spinel-rich chondrules and inclusions in carbonaceous and ordinary chondrites

    Science.gov (United States)

    Kornacki, A. S.; Fegley, B.

    1984-02-01

    The evaluation of three models of the origin of spinel-rich chondrules and inclusions presented here includes new calculations of the major-element refractory mineral condensation sequence from a gas of solar composition over a wide pressure interval. Condensation calculations show that spinel-rich chondrules did not crystallize from metastable liquid condensates, and that spinel-rich inclusions are not aggregates of refractory nebular condensates. It is proposed that spinel-rich objects are fractionated distillation residues of small aggregates of primitive dust that lost Ca, Si-rich partial melts by evaporation, ablation, or splashing during collisions. This model also explains why spinel-rich chondrules and inclusions (1) are usually smaller than melilite-rich chondrules and inclusions; (2) often have highly fractionated trace-element compositions; and (3) usually do not contain Pt-metal nuggets even when they are more enriched in the Pt-group metals than nugget-bearing melilite-rich objects.

  6. The stable Cr isotopic compositions of chondrites and silicate planetary reservoirs

    Science.gov (United States)

    Schoenberg, Ronny; Merdian, Alexandra; Holmden, Chris; Kleinhanns, Ilka C.; Haßler, Kathrin; Wille, Martin; Reitter, Elmar

    2016-06-01

    The depletion of chromium in Earth's mantle (∼2700 ppm) in comparison to chondrites (∼4400 ppm) indicates significant incorporation of chromium into the core during our planet's metal-silicate differentiation, assuming that there was no significant escape of the moderately volatile element chromium during the accretionary phase of Earth. Stable Cr isotope compositions - expressed as the ‰-difference in 53Cr/52Cr from the terrestrial reference material SRM979 (δ53/52CrSRM979 values) - of planetary silicate reservoirs might thus yield information about the conditions of planetary metal segregation processes when compared to chondrites. The stable Cr isotopic compositions of 7 carbonaceous chondrites, 11 ordinary chondrites, 5 HED achondrites and 2 martian meteorites determined by a double spike MC-ICP-MS method are within uncertainties indistinguishable from each other and from the previously determined δ53/52CrSRM979 value of -0.124 ± 0.101‰ for the igneous silicate Earth. Extensive quality tests support the accuracy of the stable Cr isotope determinations of various meteorites and terrestrial silicates reported here. The uniformity in stable Cr isotope compositions of samples from planetary silicate mantles and undifferentiated meteorites indicates that metal-silicate differentiation of Earth, Mars and the HED parent body did not cause measurable stable Cr isotope fractionation between these two reservoirs. Our results also imply that the accretionary disc, at least in the inner solar system, was homogeneous in its stable Cr isotopic composition and that potential volatility loss of chromium during accretion of the terrestrial planets was not accompanied by measurable stable isotopic fractionation. Small but reproducible variations in δ53/52CrSRM979 values of terrestrial magmatic rocks point to natural stable Cr isotope variations within Earth's silicate reservoirs. Further and more detailed studies are required to investigate whether silicate

  7. Thermoluminescence and Metamorphism in CV Chondrites

    Science.gov (United States)

    Symes, S. J. K.; Guimon, R. K.; Benoit, P. H.; Sears, D. W. G.

    1993-07-01

    One of the effects of metamorphism in meteorites is the production of feldspar, a thermoluminescence (TL) phosphor, through the devitrification of primary chondrule glass [1]. The 105-fold variation in TL sensitivity among the ordinary chondrites reflects this process and has been used successfully to subdivide the petrographic type 3 meteorites into types 3.0-3.9 [2]. Although less pronounced, the variability exhibited by the CO chondrites has also allowed petrographic subdivision of these meteorites [3]. It is possible that the CV chondrites have also experienced a range of metamorphic intensities, although McSween has warned that their petrography does not indicate a simple sequence [4]. On the other hand, Scott et al. show that the homogeneity of matrix olivine increases along the series Kaba, Mokoia, Vigarano, Grosnaja, Allende, which may indicate progressive thermal metamorphism [5]. Here we report TL sensitivity measurements for 12 whole-rock samples of CV chondrites and we suggest petrographic type assignments and discuss their metamorphic history. Samples of bulk powder were ground, the magnetic fraction removed, and the TL of 4-mg aliquots was measured three times for duplicate splits. Averages are given in Table 1, which appears in the hard copy. The CV chondrites, like the CO chondrites, generally display three peaks in their glow curves; one at 130 degrees C, which is sensitive to metamorphism at temperatures below 650 degrees C [3], one at 250 degrees C, which is metamorphism independent, and one at 350 degrees C, which might be associated with refractory minerals in CAI [6]. The TL sensitivities of these samples show a >100-fold range, the lowest being below detection limits (<0.01) and the highest being greater than the Dhajala H3.8 chondrite, which we use as a standard. Six of the 12 samples have TL sensitivities corresponding to type 3.0 if we apply the criteria proposed by Sears et al. to subdivide the CO chondrites (which are similar to those

  8. Organic Compounds in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  9. Explosive Characteristics of Carbonaceous Nanoparticles

    Science.gov (United States)

    Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

    2013-03-01

    Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V1/3 (dp/pt)max ~ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ~ 101 -102 g/m3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ~ 200 bar-m/s, placing it borderline St-1/St-2. Work supported through the NIOSH Nanotechnology Research Center (NTRC)

  10. A New CV3 Chondrite Find

    Science.gov (United States)

    Treiman, A. H.; Dehart, J. M.

    1992-07-01

    A new meteorite find from West Texas, U.S.A., is a CV3 carbonaceous chondrite. The provisional name of Red Bluff has been proposed to the Nomenclature Committee by R. Farrell. Red Bluff consists of chondrules (56.4%), CAIs (8.3%), amoboid olivine aggregates (0.6%), mineral fragments (0.8%), and Ca-Al chondrules (0.4%) in a fine-grained, clay-rich matrix (33.1%). Chondrules in Red Bluff are spherical to irregular in shape, and from 0.25-3.5 mm diameter in thin section; the average diameter is 0.95 mm, with standard deviation of 0.6 mm (69 chondrules). Three of the chondrules are distinctly larger than the rest; without these three, the average diameter is 0.86 mm (s.d. 0.4 mm). The chondrules are almost all of type I (Fe-poor), as shown by cathodoluminescence and chemical analyses; most are also rich in opaques. Compositions of chondrule olivines average Fa1.9+-1.2 (s.d.); compositions of chondrule pyroxenes average Fs3.4+-3.3 (s.d.). Chondrule varieties include porphyritic olivine, microporphyritic olivine, granular olivine, macroporphyritic olivine, barred olivine, and rare extracentroradial pyroxene (0.25 mm diam.) [1,2]. Two calcium-aluminum chondrules were observed. The largest, 1.5 mm diam., contains spinel, plagioclase, and fassaite, and includes a circular spinel palisade [3]. The other Ca-Al chondrule is within a coarse-grained CAI, and could also be a well-developed spinel palisade [3]. Fine- and coarse-grained CAIs are present but have been studied little; most appear to be type B (melilite+pyroxene+plagioclase). Red Bluff's matrix is composed of fine-grained clay, with minor olivine, "limonite," troilite, and Fe metal. Alignment of grains and oxide-rich streaks in the matrix mark a planar fabric that wraps around chondrules and inclusions. Chondrules are commonly surrounded by shells of dark red alteration, darker than the bulk of matrix material. Red Bluff is weathered. It is stained red by oxidized iron minerals, which are most common as veinlets

  11. The classification and complex thermal history of the enstatite chondrites

    Science.gov (United States)

    Zhang, Yanhong; Benoit, Paul H.; Sears, Derek W. G.

    1995-01-01

    We have carried out instrumental neutron activation analysis of 11 enstatite chondrites and electron microprobe analyses of 17 enstatite chondrites, most of which were previously little described. We report here the third known EH5 chondrite (LEW 88180) and an unusual EL6 chondrite (LEW 87119), new data on four EL3 chondrites (ALH 85119, EET 90299, PCA 91020, and MAC 88136, which is paired with MAC 88180 and MAC 88184), the second EL5 chondrite (TIL 91714), and an unusual metal-rich and sulfide-poor EL3 chondrite (LEW 87223). The often discussed differences in mineral composition displayed by the EH and EL chondrites are not as marked after the inclusion of the new samples in the database, and the two classes apparently experienced a similar range of equilibrium temperatures. However, texturally the EL chondrites appear to have experienced much higher levels of metamorphic alteration than EH chondrites of similar equilibration temperatures. Most of the petrologic type criteria are not applicable to enstatite chondrites and, unlike the ordinary chondrites, texture and mineralogy reflect different aspects of the meteorite history. We therefore propose that the existing petrologic type scheme not be used for enstatite chondrites. We suggest that while 'textural type' reflects peak metamorphic temperatures, the 'mineralogical type' reflects equilibration during postmetamorphic (probably regolith) processes. Unlike the ordinary chondrites and EH chondrites, EL chondrites experienced an extensive low-temperature metamorphic episode. There are now a large number of enstatite meteorite breccias and impact melts, and apparently surface processes were important in determining the present nature of the enstatite chondrites.

  12. The matrices of unequilibrated ordinary chondrites - Implications for the origin and history of chondrites

    Science.gov (United States)

    Huss, G. R.; Keil, K.; Taylor, G. J.

    1981-01-01

    The matrices of 16 unequilibrated chondrites were examined by optical microscopy, an electron microprobe, and a scanning electron microscope. The fine-grained, opaque, silicate matrix of type 3 unequilibrated chondrites was compositionally, mineralogically, and texturally different from the chondrules and their fragments; it may be the low temperature condensate proposed by Larimer and Anders (1967, 1970). Each meteorite has been metamorphosed by a combination of processes including thermal metamorphism and the passage of shock waves; the appearance of each chondrite results from the temperature and pressure conditions which formed it, and subsequent metamorphic alterations.

  13. EXTREME 16O ENRICHMENT IN CALCIUM-ALUMINUM-RICH INCLUSIONS FROM THE ISHEYEVO (CH/CB) CHONDRITE

    International Nuclear Information System (INIS)

    Calcium-aluminum-rich inclusions (CAIs) from the metal-rich (CH/CB-like) carbonaceous chondrite Isheyevo are mineralogically pristine and show no evidence for postcrystallization alteration. Many of them are composed of very refractory minerals, such as hibonite (CaAl12O19), grossite (CaAl4O7), aluminum-rich pyroxene, and perovskite (CaTiO3). Twenty-eight out of 35 studied CAIs from Isheyevo have oxygen isotopic compositions similar to those of CAIs from the CM and CR carbonaceous chondrites (Δ17O ∼ -20 per mille ). Five igneous CAIs are 16O-depleted to a level observed in Isheyevo chondrules (Δ17O ∼> -10 per mille ), suggesting remelting and isotope exchange in an 16O-poor gaseous reservoir. Two CAIs, WA9 and B1, show the highest enrichment in 16O (δ17O ∼ -68 per mille , δ18O ∼ -66 per mille , Δ17O ∼ -34 per mille ) ever observed among refractory inclusions. In the context of the self-shielding model for the evolution of oxygen isotopes in the solar accretion disk, these CAIs may have recorded the initial oxygen isotopic composition of the solar system, and hence of the Sun.

  14. Iron-Nickel Sulfide Compositional Ranges in CM Chondrites: No Simple Plan

    Science.gov (United States)

    Zolensky, Michael; Le, Loan

    2003-01-01

    Iron-nickel sulfides are found in most or all solar system environments, and are probably the only minerals found in all extraterrestrial materials on hand. Despite this ubiquity, they have only just begun the attention they deserve. The most common Fe-Ni sulfides in chondrites are troilite (FeS), pyrrhotite (Fe(1-x)S) and pentlandite (Fe,Ni)9S8. Troilite is believed to have resulted from sulfidation of metal (Fe-Ni) grains in an H2S-containing environment. Pyrrhotite is produced when friable troilite grains, which are exfoliated from the metal nucleus, are submitted to continued sulfidation. Some asteroids are known to have experienced aqueous alteration, forming products including new generations of sulfides (pyrrhotite and pentlandite). Pentlandite in particular is known to form during such alteration. However, experimental work by Lauretta has indicated that pentlandite may also have been formed during the initial sulfidation process, due to the faster diffusion rate of nickel into the forming sulfide, as compared to iron. Finally, there is considerable evidence for a family of phases intermediate between pyrrhotite and pentlandite, following the trend of the high temperature monosulfide solid solution, something not encountered in terrestrial rocks. Each sulfide has its own particular stability conditions, which have been determined for most phases. The long-term objective of our research is to characterize sulfides in chondritic materials in order to better establish the conditions under which they formed, and the subsequent processes they experienced. Ultimately, it will be possible to infer whether the sulfides in the chondrites were formed in the solar nebula or on asteroids, and if formed on the asteroids, deduce how much alteration has occurred there. Here we explore the relationships between the finest grain size portions of carbonaceous chondrites, these being matrix and chondrule rims; fine-grained materials are the most sensitive to their environment

  15. Chondrites as samples of differentiated planetesimals

    Science.gov (United States)

    Elkins-Tanton, Linda; Weiss, Benjamin P.; Zuber, Maria T.

    2010-05-01

    Chondritic meteorites are unmelted, variably metamorphosed samples of the earliest solids of the solar system. A recent paleomagnetic study of CV chondrites suggests that their parent body was internally differentiated and produced a core magnetic dynamo (Carporzen et al., submitted, and this session). Here we show that a parent body that accreted to >250 km in radius by ~1.7 Ma after the formation of CAIs could retain a solid undifferentiated crust overlying a differentiated interior, and would be consistent with formational and evolutionary constraints on the CV parent body. Further, this body could have produced a magnetic field lasting more than 10 Ma. CV chondritic meteorites contain the oldest known solids: calcium-aluminum-rich inclusions (CAIs). The variety of metamorphic textures in ordinary chondrites motivated the "onion shell" model in which chondrites originated at varying depths within a parent body heated primarily by the short-lived radioisotope 26Al, with the highest metamorphic grade originating nearest the center. The large abundances and sizes of CAIs in CV chondrites have long suggested an early parent body accretion age. New Pb-Pb and Al-Mg ages of chondrules in CVs are consistent with the CV parent body having largely completed accretion by the youngest chondrule age of ~1.7-3 Ma. The CV chondrite parent body likely reached peak metamorphic temperatures around 7 to 10 Ma after CAIs, based on I-Xe chronometry for Allende and Mn-Cr chronometry for Mokoia. Bodies that accreted to more than >~20 km radius before ~1.3 to 3 Ma after the formation of CAIs likely contained sufficient 26Al to melt internally from the insulated cumulative effects of radiogenic heating. These early-accreting bodies will melt from the interior out, sometimes forming an interior magma ocean under a solid, conductive, undifferentiated shell. This shell would consist of the same chondritic material that made up the bulk accreting body before melting began. The presence of

  16. Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

    Science.gov (United States)

    Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.

    2016-01-01

    Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

  17. Radiation swelling of carbonaceous materials

    International Nuclear Information System (INIS)

    Radiation swelling occurs in practically all studied materials at a certain temperature range and irradiation dose. It consists of an increase of the volume and a corresponding decrease of the density and is accompanied by weakening. Swelling is usually divided into three stages (periods). Incubation involves little or no swelling. The transitional period occurs when the volume increases as a power function of the dose with an exponent n > 1. The dependence on the dose is linear in the steady period. The dependence of the swelling rate on temperature is bell-shaped. Anisotropic secondary swelling is observed in carbonaceous construction materials at T > 750-850 K and a flux ∼1022 neutrons/cm2. Three swelling stages are found. These are incubation, transitional, and steady. The transitional stage shifts to smaller neutron fluxes as the temperature increases. The swelling rate in the third stage is constant and has a maximum at 950-1300 K. The value of the maximum is determined by the structure of the graphite and increases with increasing density

  18. Biological potential of extraterrestrial materials - 1. Nutrients in carbonaceous meteorites, and effects on biological growth

    Science.gov (United States)

    Mautner, Michael N.

    1997-06-01

    Soil nutrient analysis of the Murchison C2 carbonaceous chondrite shows biologically available S, P, Ca, Mg, Na, K and Fe and cation exchange capacity (CEC) at levels comparable with terrestrial agricultural soils. Weathering, and aqueous, hydrothermal (121°C, 15 min) and high-temperature (550°C, 3 h) processing increase the extractable nutrients. Extractable phosphorus (by 0.3 M NH 4F + 0.1 M HCl) content, which may be growth-limiting, is 6.3 μg g -1 in the unprocessed meteorite, but increases to 81 μg g -1 by hydrothermal processing and weathering, and to 130 μg g -1 by high temperature processing. The cation exchange capacity (CEC), attributed mainly to the organic fraction, corresponds responds to 345 meq per 100 g of the polymer, suggesting one ionizable COOH or OH group per 3-4 aromatic rings. The Allende C3(V) meteorite has low extractable Ca, Mg and K, in parallel to its low organic content and CEC, but high extractable P levels (160 μg g -1). Biological effects are observed on growth of the soil microorganisms Flavobacterium oryzihabitans and Nocardia asteroides in meteorite extracts, and the population levels suggest that P is the limiting nutrient. Effects on plant growth are examined on Solanum tuberosum (potato), where extracts of the Murchison meteorite lead to enhanced growth and pigmentation. The biologically available organic and inorganic nutrients in carbonaceous chondrites can provide concentrated solutions for prebiotic and early life processes, and serve as soils and fertilizers for future space-based biological expansion.

  19. Rumuruti: A New Carlisle Lakes-type Chondrite

    Science.gov (United States)

    Schulze, H.; Otto, J.

    1993-07-01

    +-content is required (12-51 mol% of the iron). The mean composition of this spinel phase can be expressed as a mixture of the end members chromite (55 mol%), ulvospinel (17 mol%), magnetite (15 mol%), and spinel (9 mol%). Only the magnetite (4-25 mol%) and the chromite component (46-68 mol%) are strongly variable, obviously substituting each other. Chromian spinel occurs intergrown with the sulfides, as xenomorphic or chondrulelike individual grains (up to 200 micrometers) or as inclusions in the olivine. Nickel-iron is a rare phase. Only four grains of up to 30 micrometers have been observed. It seems to be associated with pentlandite and is very rich in Ni (67 wt% Ni). The homogeneity of the olivine and the grain size of plagioclase indicates a classification as a type-4 chondrite, whereas some glass in a chondrule points also to type 3. A refined investigation of clasts and groundmass will provide more clarity. Rumuruti is only mildly shocked (S2 according to [4]), but a vein restricted to one of the light clasts indicates that components of the meteorite experienced higher shock pressures. The unusual assemblage of fayalite-rich olivine (Fa39), Ti- and Fe3+-rich chromite, pentlandite, pyrrhotite, and chalcopyrite is comparable to the highly oxidized Carlisle Lakes-type meteorites [3,5]. Rumuruti now brings this group, together with Carlisle Lakes, ALH85151, Y75302 [3], and Acfer 217 [6], to five meteorites where Rumuruti is the first observed fall. References: [1] Van Schmus W. R. and Ribbe P. H. (1968) GCA, 32, 1327-1342. [2] Van Schmus W. R. and Ribbe P. H. (1969) GCA, 33, 637-640. [3] Rubin A. E. and Kallemeyn G. W. (1989) GCA, 53, 3035-3044. [4] Stoffler D. et al. (1991) GCA, 55, 3845-3867. [5] Weisberg M. K. et al. (1991) GCA, 55, 2657-2669. [6] Bischoff A. et al. (1993) Meteoritics, submitted.

  20. Thermal evolution and sintering of chondritic planetesimals. III. Modelling the heat conductivity of porous chondrite material

    Science.gov (United States)

    Henke, Stephan; Gail, Hans-Peter; Trieloff, Mario

    2016-05-01

    Context. The construction of models for the internal constitution and temporal evolution of large planetesimals, which are the parent bodies of chondrites, requires as accurate as possible information on the heat conductivity of the complex mixture of minerals and iron metal found in chondrites. The few empirical data points on the heat conductivity of chondritic material are severely disturbed by impact-induced microcracks modifying the thermal conductivity. Aims: We attempt to evaluate the heat conductivity of chondritic material with theoretical methods. Methods: We derived the average heat conductivity of a multi-component mineral mixture and granular medium from the heat conductivities of its mixture components. We numerically generated random mixtures of solids with chondritic composition and packings of spheres. We solved the heat conduction equation in high spatial resolution for a test cube filled with such matter. We derived the heat conductivity of the mixture from the calculated heat flux through the cube. Results: For H and L chondrites, our results are in accord with empirical thermal conductivity at zero porosity. However, the porosity dependence of heat conductivity of granular material built from chondrules and matrix is at odds with measurements for chondrites, while our calculations are consistent with data for compacted sandstone. The discrepancy is traced back to subsequent shock modification of the currently available meteoritic material resulting from impacts on the parent body over the last 4.5 Ga. This causes a structure of void space made of fractures/cracks, which lowers the thermal conductivity of the medium and acts as a barrier to heat transfer. This structure is different from the structure that probably exists in the pristine material where voids are represented by pores rather than fractures. The results obtained for the heat conductivity of the pristine material are used for calculating models for the evolution of the H chondrite

  1. Trace element geochemistry of CR chondrite metal

    CERN Document Server

    Jacquet, Emmanuel; Alard, Olivier; Kearsley, Anton T; Gounelle, Matthieu

    2015-01-01

    We report trace element analyses by laser ablation inductively coupled plasma mass spectrometry of metal grains from 9 different CR chondrites, distinguishing grains from chondrule interior ("interior grains"), chondrule surficial shells ("margin grains") and the matrix ("isolated grains"). Save for a few anomalous grains, Ni-normalized trace element patterns are similar for all three petrographical settings, with largely unfractionated refractory siderophile elements and depleted volatile Au, Cu, Ag, S. All types of grains are interpreted to derive from a common precursor approximated by the least melted, fine-grained objects in CR chondrites. This also excludes recondensation of metal vapor as the origin of the bulk of margin grains. The metal precursors presumably formed by incomplete condensation, with evidence for high-temperature isolation of refractory platinum-group-element (PGE)-rich condensates before mixing with lower temperature PGE-depleted condensates. The rounded shape of the Ni-rich, interior ...

  2. Thermal history modeling of the H chondrite parent body

    CERN Document Server

    Henke, Stephan; Trieloff, Mario; Schwarz, Winfried H; Kleine, Thorsten

    2012-01-01

    The cooling histories of individual meteorites can be empirically reconstructed by using ages from different radioisotopic chronometers with distinct closure temperatures. For a group of meteorites derived from a single parent body such data permit the reconstruction of the cooling history and properties of that body. Particularly suited are H chondrites because precise radiometric ages over a wide range of closure temperatures are available. A thermal evolution model for the H chondrite parent body is constructed by using all H chondrites for which at least three different radiometric ages are available. Several key parameters determining the thermal evolution of the H chondrite parent body and the unknown burial depths of the H chondrites are varied until an optimal fit is obtained. The fit is performed by an 'evolution algorithm'. Empirical data for eight samples are used for which radiometric ages are available for at least three different closure temperatures. A set of parameters for the H chondrite pare...

  3. Chronology of enstatite chondrites and ureilites

    International Nuclear Information System (INIS)

    This paper summarizes the chronological studies on enstatite chondrites and ureilites, both of which are special groups of meteorites with unknown origins. Two unequilibrated enstatite chondrites, Qingzhen and Yamato 6901 (E3), showed the highly disturbed Rb-Sr system, while their silicate fractions yielded the 2.1 Ga isochron. The thermally metamorphosed enstatite chondrite Khairpur (E6) showed the older Rb-Sr age of 4.50 Ga. The parent body of E3 chondrites experienced late thermal event at low temperature, which broke down alkali-bearing sulfides in E3. The observed Rb-Sr data are consistent with the mobilization of Rb from alkali-sulfide to silicate phases. Ureilites show highly depleted trace elements abundance which makes it difficult to determine the age of the formation. The U-Pb and Sm-Nd age determination of low-Ca ureilite Goalpara showed that the Pb and Nd isotopes are heavily contaminated with terrestrial components. The acid residues of high-Ca ureilite MET-78008 were free of contamination and defined the old U-Pb age of 4.563±0.006 Ga. The early formation of ureilites supports their formation through the collisional destruction of the parent body. Including the ureilite date, many evolved meteorites formed within the first 10 million years of the solar system history. Future studies on meteorite chronology with the purpose of understanding the early history of the solar system should focus on the fine time resolution through the precise U-Pb age determination or the relative age determination using the extinct nuclides with half lives less than 10 million years. (author)

  4. Internal Structure and Mineralogy of Differentiated Asteroids Assuming Chondritic Bulk Composition: The Case of Vesta

    Science.gov (United States)

    Toplis, M. J.; Mizzon, H.; Forni, O.; Monnereau, M.; Prettyman, T. H.; McSween, H. Y.; McCoy, T. J.; Mittlefehldt, D. W.; DeSanctis, M. C.; Raymond, C. A.; Russell, C. T.

    2012-01-01

    dominated by olivine (>85%) for carbonaceous chondrites, but to be a roughly equal mixture of olivine and pyroxene for ordinary chondrite precursors. All bulk compositions have a significant core, but the relative proportions of metal and sulphide can be widely different. Using these data, total core size (metal+ sulphide) and average core densities can be calculated, providing a useful reference frame within which to consider geophysical/gravity data of the Dawn mission.

  5. The Cerro LOS Calvos and La Banderia chondrites

    Science.gov (United States)

    Whitlock, Randall; Lewis, Charles F.; Clark, James C.; Moore, Carleton B.

    1991-06-01

    The Cerro los Calvos meteorite is a single stone of 68.5 g found in the Nuevo Mercurio strewn field of Zacatecas, (Mexico). It is an unusual H4 chondrite. Its olivine (Fa12.5) and orthopyroxene (Fs 11.7, Wo 0.8) are reduced relative to typical H chondrites. The La Banderia meteorite of 54.3 g from the same vicinity is an LL5 chondrite of shock classification e.

  6. Chemistry and oxygen isotopic composition of cluster chondrite clasts and their components in LL3 chondrites

    Science.gov (United States)

    Metzler, Knut; Pack, Andreas

    2016-02-01

    Cluster chondrites are characterized by close-fit textures of deformed and indented chondrules, taken as evidence for hot chondrule accretion (Metzler). We investigated seven cluster chondrite clasts from six brecciated LL3 chondrites and measured their bulk oxygen isotopic and chemical composition, including REE, Zr, and Hf. The same parameters were measured in situ on 93 chondrules and 4 interchondrule matrix areas. The CI-normalized REE patterns of the clasts are flat, showing LL-chondritic concentrations. The mean chemical compositions of chondrules in clasts and other LL chondrites are indistinguishable and we conclude that cluster chondrite chondrules are representative of the normal LL chondrule population. Type II chondrules are depleted in MgO, Al2O3 and refractory lithophiles (REE, Zr, Hf) by factors between 0.65 and 0.79 compared to type I chondrules. The chondrule REE patterns are basically flat with slight LREE fractionations. Many chondrules exhibit negative Eu anomalies while matrix shows a complementary pattern. Chondrules scatter along a correlation line with a slope of 0.63 in the oxygen 3-isotope diagram, interpreted as the result of O-isotope exchange between chondrule melts and 18O-rich nebular components. In one clast, a distinct anticorrelation between chondrule size and δ18O is found, which may indicate a more intense oxygen isotope exchange by smaller chondrules. In some clasts the δ18O values of type I chondrules are correlated with concentrations of SiO2 and MnO and anticorrelated with MgO, possibly due to the admixture of a SiO2- and MnO-rich component to chondrule melts during oxygen isotope exchange. Two chondrules with negative anomalies in Sm, Eu, and Yb were found and may relate their precursors to refractory material known from group III CAIs. Furthermore, three chondrules with strong LREE > HREE and Zr/Hf fractionations were detected, whose formation history remains to be explained.

  7. A Collisional Origin to Earth's Non-chondritic Composition?

    OpenAIRE

    Bonsor, Amy; Leinhardt, Zoë M.; Carter, Philip J.; Elliott, Tim; Walter, Michael J.; Stewart, Sarah T.

    2014-01-01

    Several lines of evidence indicate a non-chondritic composition for Bulk Earth. If Earth formed from the accretion of chondritic material, its non-chondritic composition, in particular the super-chondritic 142Nd/144Nd and low Mg/Fe ratios, might be explained by the collisional erosion of differentiated planetesimals during its formation. In this work we use an N-body code, that includes a state-of-the-art collision model, to follow the formation of protoplanets, similar to proto-Earth, from d...

  8. Graphite-magnetite aggregates in ordinary chondritic meteorites

    Science.gov (United States)

    Scott, E. R. D.; Taylor, G. J.; Rubin, A. E.; Keil, K.; Okada, A.

    1981-01-01

    The graphite-magnetite component has been found (1) as abundant isolated inclusions in eight ordinary-chondritic, regolith breccias; (2) as the sole matrix in a new kind of unequilibrated chondrite that forms clasts in these regolith breccias; and (3) together with a Huss matrix in six unequilibrated ordinary chondrites. It is suggested that the component was formed by low-temperature, gas-solid reactions before the accretion of the meteorite, and that the isolated inclusions of graphite-magnetite in regolith breccias were derived from bodies composed of the new kind of chondrite that has graphite-magnetite as its sole matrix.

  9. Petrology and Cosmochemistry of a Suite of R Chondrites

    Science.gov (United States)

    Torrano, Z. A.; Mittlefehldt, D. W.; Peng, Z. X.

    2015-01-01

    Chondrites are among the most primitive surviving materials from the early solar system. They are divided into groups based on chemical types defined by mineralogy, bulk composition, and oxygen isotope compositions. Chondrites range in petrographic grade from type 1 to type 7. Type 3 chondrites are the most primitive and are little changed from the nebular solids accreted to form asteroids. They are composed of chondrules, fine-grained matrix, metal and sulfide, plus or minus Ca-Al-rich inclusions. With increasing aqueous alteration at low temperatures, members of some chondrite classes transformed from type 3 towards type 1. With increasing thermal metamorphism and low fluid content, members of other classes changed from type 3 towards type 7. Rumuruti (R) chondrites are a rare group (0.1% of falls) similar to ordinary chondrites in some properties but different in others. They are characterized by low chondrule/matrix modal abundance ratios, high oxidation state, small mean chondrule size, abundant sulfides and low metal contents. R chondrites vary in petrologic type from 3 to 6. They are important objects to study because some of them have undergone metamorphism at high temperatures in the presence of aqueous fluids. In contrast, CM and CI chondrites were heated to low temperatures in the presence of aqueous fluids leading to alteration; they contain low-T hydrous phases (phyllosilicates) and little or no remaining metal. Ordinary chondrites were heated to high temperatures in a low-fluid environment resulting in anhydrous metamorphic rocks. R6 chondrites are highly metamorphosed and some contain the high-T hydrous phases mica and amphibole. R chondrites are thus unique and give us an opportunity to examine whether there are compositional effects caused by high-T, highfluid metamorphism of nebular materials.

  10. Thermal evolution and sintering of chondritic planetesimals III. Modelling the heat conductivity of porous chondrite material

    CERN Document Server

    Henke, Stephan; Trieloff, Mario

    2016-01-01

    The construction of models for the internal constitution and the temporal evolution of large planetesimals, the parent bodies of chondrites, requires information on the heat conductivity of the complex mixture of minerals and iron metal found in chondrites. It is attempted to evaluate the heat conductivity of a multi-component mineral mixture and granular medium from the heat conductivities of its mixture components. Random mixtures of solids with chondritic composition and packings of spheres are numerically generated. The heat conduction equation is solved in high spatial resolution for a test cube filled with such matter. From the heat flux through the cube the heat conductivity of the mixture is derived. The model results for porous material are consistent with data for compacted sandstone, but are at odds with measurements for H and L chondrites. The discrepancy is traced back to shock modification of the currently available meteoritic material by impacts on the parent body over the last 4.5 Ga. This cau...

  11. Chromium on Eros: Further Evidence of Ordinary Chondrite Composition

    Science.gov (United States)

    Foley, C. N.; Nittler, L. R.; Brown, M. R. M.; McCoy, T. J.; Lim, L. F.

    2005-01-01

    The surface major element composition of the near-earth asteroid 433-Eros has been determined by x-ray fluorescence spectroscopy (XRS) on the NEAR-Shoemaker spacecraft [1]. The abundances of Mg, Al, Si, Ca and Fe match those of ordinary chondrites [1]. However, the observation that Eros appears to have a sulfur abundance at least a factor of two lower than ordinary chondrites, suggests either sulfur loss from the surface of Eros by impact and/or radiation processes (space weathering) or that its surface is comprised of a somewhat more differentiated type of material than an ordinary chondrite [1]. A definitive match for an ordinary chondrite parent body has very rarely been made, despite the conundrum that ordinary chondrites are the most prevalent type of meteorite found on Earth. Furthermore, Eros is classified as an S(IV) type asteroid [2] and being an S, it is the second most prevalent type of asteroid in the asteroid belt [3].

  12. Effects of viewing geometry, aggregation state, and particle size on reflectance spectra of the Murchison CM2 chondrite deconvolved to Dawn FC band passes

    Science.gov (United States)

    Izawa, Matthew R. M.; Schäfer, Tanja; Pietrasz, Valerie B.; Cloutis, Edward A.; Mann, Paul; Nathues, Andreas; Mengel, Kurt; Schäfer, Michael; Thangjam, Guneshwar; Hoffmann, Martin; Tait, Kimberly T.; Applin, Daniel M.

    2016-03-01

    Several current and soon-to-launch missions will investigate 'dark' asteroids, whose spectra have few weak or no distinct spectral features. Some carbonaceous chondrites, particularly the CI and CM groups, are reasonable material analogues for many dark asteroid surfaces. In addition to compositional variations, many non-compositional effects, including viewing geometry, surface particle size and particle sorting, can influence reflectance spectra, potentially complicating mineralogical interpretation of such data from remote surfaces. We have carried out an investigation of the effects of phase angle, particle size, aggregation state, and intra-sample heterogeneity on the reflectance spectra (0.4-1.0 μm) of the Murchison CM2 carbonaceous chondrite, deconvolved to Dawn Framing Camera (FC) band passes. This study was motivated by the desire to derive information about the surface of Ceres from Dawn FC data. Key spectral parameters derived from the FC multispectral data include various two-band reflectance ratios as well as three-band ratios that have been derived for mineralogical analysis. Phase angle effects include increased visible slope with increasing phase angle, a trend that may reverse at very high phase angles. Fine-grained particles exert a strong influence on spectral properties relative to their volumetric proportion. Grain size variation effects include a decrease in spectral contrast and increased visible spectral slope with decreasing grain size. Intra-sample heterogeneity, while spectrally detectable, is of relatively limited magnitude.

  13. Application of an alkylammonium method for characterization of phyllosilicates in CI chondrites

    Science.gov (United States)

    Golden, D. C.; Ming, D. W.; Zolensky, M. E.; Yang, S. V.

    1994-01-01

    Many meteorites and interplanetary dust particles (IDP's) with primitive compositions contain significant amounts of phyllosilicates, which are generally interpreted as evidence of protoplanetary aqueous alteration at an early period in the solar system. These meteorites are chondrites of the carbonaceous and ordinary varieties. Characterization of phyllosilicates in these materials is important because of the important physico-chemical information they hold, e.g., from well characterized phyllosilicates, thermodynamic stability relations and hence the conditions of formation of phyllosilicates in the parent body of the meteorite can be predicted. Although we are at a rudimentary level of understanding of the minerals resulting from the aqueous alteration in the early solar nebula, we know that the most common phyllosilicates present in chondritic extraterrestrial materials are serpentines, smectites, chlorites, and micas. The characterization of fine grained minerals in meteorites and IDP's rely heavily on electron beam instruments, especially transmission electron microscopy (TEM). Typically, phyllosilicates are identified by a combination of high resolution imaging of basal spacings, electron diffraction analysis, and chemical analysis. Smectites can be difficult to differentiate from micas because the smectites loose their interlayer water and the interlayers collapse to the same basal spacing as mica in the high vacuum of the TEM. In high-resolution TEM (HRTEM) images, smectite basal spacings vary from 1 nm up to 1.5 nm, while micas show 1 or 2 nm basal spacings. Not only is it difficult to differentiate smectites from micas, but there is no way of identifying different classes of smectites in meteorites and IDP's. To differentiate smectites from micas and also to recognize the charge differences among smectites, an alkylammonium method can be employed because the basal spacings of alkylammonium saturated smectites expand as a function of alkylamine chain

  14. Organic Analysis in the Miller Range 090657 CR2 Chondrite: Part 2 Amino Acid Analyses

    Science.gov (United States)

    Burton, A. S.; Cao, T.; Nakamura-Messenger, K.; Berger, E. L.; Messenger, S.; Clemett, S. J.; Aponte, J. C.; Elsila, J. E.

    2016-01-01

    Primitive carbonaceous chondrites contain a wide variety of organic material, ranging from soluble discrete molecules to insoluble, unstructured kerogen-like components, as well as structured nano-globules of macromolecular carbon. The relationship between the soluble organic molecules, macromolecular organic material, and host minerals are poorly understood. Due to the differences in extractability of soluble and insoluble organic materials, the analysis methods for each differ and are often performed independently. The combination of soluble and insoluble analyses, when performed concurrently, can provide a wider understanding of spatial distribution, and elemental, structural and isotopic composition of organic material in primitive meteorites. Using macroscale extraction and analysis techniques in combination with in situ microscale observation, we have been studying both insoluble and soluble organic material in the primitive CR2 chondrite Miller Range (MIL) 090657. In accompanying abstracts (Cao et al. and Messenger et al.) we discuss insoluble organic material in the samples. By performing the consortium studies, we aim to improve our understanding of the relationship between the meteorite minerals and the soluble and insoluble organic phases and to delineate which species formed within the meteorite and those that formed in nebular or presolar environments. In this abstract, we present the results of amino acid analyses of MIL 090657 by ultra performance liquid chromatography with fluorescence detection and quadrupole-time of flight mass spectrometry. Amino acids are of interest because they are essential to life on Earth, and because they are present in sufficient structural, enantiomeric and isotopic diversity to allow insights into early solar system chemical processes. Furthermore, these are among the most isotopically anomalous species, yet at least some fraction are thought to have formed by aqueously-mediated processes during parent body alteration.

  15. Thermal recalcitrance of the organic D-rich component of ordinary chondrites

    Science.gov (United States)

    Remusat, L.; Piani, L.; Bernard, S.

    2016-02-01

    Carbonaceous and ordinary chondrites (CCs and OCs) contain insoluble organic matter (IOM) with large D-excess compared to other objects in the solar system. The higher the temperature experienced by CCs, the lower the D/H ratio of their IOM. It seems to be the opposite for OCs. Here, we report NanoSIMS H- (and N-) isotopic imaging of IOM of three OCs that experienced thermal metamorphism in the sequence Semarkona, Bishunpur and GRO 95502. In addition, we performed flash heating experiments on the IOM of GRO 95502 at 600 °C and characterized the residues using NanoSIMS, Raman and XANES spectroscopy. The present study shows that, in contrast to IOM of CI, CM and CR, IOM of OCs exhibits very few D-rich (or 15N-rich) hotspots. Furthermore, although the evolution of the molecular structure of OC and CC IOM is similar upon heating, their D/H ratios do not follow the same trend: the D/H of OC IOM drastically increases while the D/H of CC IOM decreases. In contrast to CC IOM, the D-rich component of which does not survive at high temperatures, the present results highlight the thermal recalcitrance of the D-rich component of OC IOM. This suggests that CCs and OCs did not accrete the same organic material, thereby challenging the hypothesis of a common precursor on chondritic parent bodies. The present results support the hypothesis that OC IOM contains an organic component that could originate from the interstellar medium.

  16. The isotope composition of selenium in chondrites constrains the depletion mechanism of volatile elements in solar system materials

    Science.gov (United States)

    Vollstaedt, Hauke; Mezger, Klaus; Leya, Ingo

    2016-09-01

    Solar nebula processes led to a depletion of volatile elements in different chondrite groups when compared to the bulk chemical composition of the solar system deduced from the Sun's photosphere. For moderately-volatile elements, this depletion primarily correlates with the element condensation temperature and is possibly caused by incomplete condensation from a hot solar nebula, evaporative loss from the precursor dust, and/or inherited from the interstellar medium. Element concentrations and interelement ratios of volatile elements do not provide a clear picture about responsible mechanisms. Here, the abundance and stable isotope composition of the moderately- to highly-volatile element Se are investigated in carbonaceous, ordinary, and enstatite chondrites to constrain the mechanism responsible for the depletion of volatile elements in planetary bodies of the inner solar system and to define a δ 82 / 78 Se value for the bulk solar system. The δ 82 / 78 Se of the studied chondrite falls are identical within their measurement uncertainties with a mean of - 0.20 ± 0.26 ‰ (2 s.d., n = 14, relative to NIST SRM 3149) despite Se abundance depletions of up to a factor of 2.5 with respect to the CI group. The absence of resolvable Se isotope fractionation rules out a kinetic Rayleigh-type incomplete condensation of Se from the hot solar nebula or partial kinetic evaporative loss on the precursor material and/or the parent bodies. The Se depletion, if acquired during partial condensation or evaporative loss, therefore must have occurred under near equilibrium conditions to prevent measurable isotope fractionation. Alternatively, the depletion and cooling of the nebula could have occurred simultaneously due to the continuous removal of gas and fine particles by the solar wind accompanied by the quantitative condensation of elements from the pre-depleted gas. In this scenario the condensation of elements does not require equilibrium conditions to avoid isotope

  17. Characterisation of carbonaceous particulate matter in Edinburgh

    OpenAIRE

    Hammonds, Mark David

    2012-01-01

    Airborne particulate matter (PM) has important harmful effects on human health, as well as a number of other important atmospheric effects. Although progress has been made in understanding the sources and effects of PM, there remains considerable uncertainty on a number of issues, including the nature of a lot of the carbonaceous material, which comprises 30{50% on average of PM mass. This project aims to compare different methods of PM measurement, and contribute understanding...

  18. Carbonaceous aerosols in an urban tunnel

    Science.gov (United States)

    Ancelet, Travis; Davy, Perry K.; Trompetter, William J.; Markwitz, Andreas; Weatherburn, David C.

    2011-08-01

    Particulate matter in the Mount Victoria Tunnel, an urban road tunnel 623 m in length with an average traffic volume of 2070-2300 vehicles per hour located in Wellington, New Zealand, was studied to gain an understanding of carbonaceous species emitted from motor vehicles. The average PM 2.5 concentration during peak hours in the tunnel was found to be 67.6 ± 19.4 μg m -3. Analysis of carbonaceous species present (OC, EC, TC) was performed by both the NIOSH and IMPROVE thermal/optical protocols and carbonaceous species were found to make up 63-73% of the total PM in the tunnel. Comparison of TC concentrations obtained from each protocol revealed that no significant difference was present between the two protocols. Black carbon (BC), also used as a measure of EC, was determined using light reflection and BC values did not differ significantly from EC concentrations determined using the NIOSH and IMPROVE protocols. TC was also determined using EA/IRMS and it was found that TC concentrations from EA/IRMS directly correlated with TC results obtained using the NIOSH protocol. Stable isotope analysis of the PM 2.5 yielded δ 13C values from -24.7 to -28.3‰, typical of motor vehicles. Analysis of particle-phase PAHs by thermal desorption GC/MS revealed an average total PAH concentration of 70.0 ± 4.1 ng m -3 and PAHs were found to contribute 0.10% of total PM 2.5 in the tunnel. PAH emissions in the tunnel were found to be enriched in low molecular weight PAHs, indicative of emissions from diesel-fueled vehicles. Analysis of individual particle composition and morphology revealed that most particles were carbonaceous species that formed large, amorphous agglomerates made up of smaller spherules.

  19. Coordinated Isotopic and Mineral Characterization of Highly Fractionated 18O-Rich Silicates in the Queen Alexandra Range 99177 CR3 Chondrite

    Science.gov (United States)

    Nguyen, A. N.; Keller, L. P.; Messenger, S.; Rahman, Z.

    2016-01-01

    Carbonaceous chondrites contain a mixture of solar system condensates, pre-solar grains, and primitive organic matter. Each of these materials record conditions and processes in different regions of the solar nebula, on the meteorite parent body, and beyond the solar system. Oxygen isotopic studies of meteorite components can trace interactions of distinct oxygen isotopic reservoirs in the early solar system and secondary alteration processes. The O isotopic compositions of the earliest solar system condensates fall along a carbonaceous chondrite anhydrous mineral (CCAM) line of slope approximately 1 in a plot of delta 17O against delta 18O. This trend is attributed to mixing of material from 16O-poor and 16O-rich reservoirs. Secondary processing can induce mass-dependent fractionation of the O isotopes, shifting these compositions along a line of slope approximately 0.52. Substantial mass-dependent fractionation of O isotopes has been observed in secondary minerals in CAIs, calcite, and FUN inclusions. These fractionations were caused by significant thermal or aqueous alteration. We recently reported the identification of four silicate grains with extremely fractionated O isotopic ratios (delta 18O equals 37 - 55 per mille) in the minimally altered CR3 chondrite QUE 99177. TEM analysis of one grain indicates it is a nebular condensate that did not experience substantial alteration. The history of these grains is thus distinct from those of the aforementioned fractionated materials. To constrain the origin of the silicate grains, we conducted further Mg and Fe isotopic studies and TEM analyses of two grains.

  20. Oxygen Isotope Evidence for the Relationship between CM and CO Chondrites: Could they Both Coexist on a Single Asteroid

    Science.gov (United States)

    Greenwood, R. C.; Howard, K. T.; Franchi, I. A.; Zolensky, M. E.; Buchanan, P. C.; Gibson, J. M.

    2014-01-01

    Water played a critical role in the early evolution of asteroids and planets, as well as being an essential ingredient for life on Earth. However, despite its importance, the source of water in the inner solar system remains controversial. Delivery of water to Earth via comets is inconsistent with their relatively elevated D/H ratios, whereas carbonaceous chondrites (CCs) have more terrestrial-like D/H ratios [1]. Of the eight groups into which the CCs are divided, only three (CI, CM, CR) show evidence of extensive aqueous alteration. Of these, the CMs form the single most important group, representing 34% of all CC falls and a similar percentage of finds (Met. Bull. Database). CM material also dominates the population of CC clasts in extraterrestrial samples [2, 3]. The Antarctic micrometeorites population is also dominated by CM and CI-like material and similar particles may have transported water and volatiles to the early Earth [4]. CCs, and CMs in particular, offer the best opportunity for investigating the evolution of water reservoirs in the early solar system. An important aspect of this problem involves identifying the anhydrous silicate component which co-accreted with ice in the CM parent body. A genetic relationship between the essentially anhydrous CO group and the CMs was proposed on the basis of oxygen isotope evidence [5]. However, previous CM whole-rock oxygen isotope data scattered about a line of approximately 0.5 that did not intersect the field of CO chondrites [5]. Here we discuss new oxygen isotope data which provides additional constraints on the relationship between CO and CM chondrites.

  1. Investigation of magnesium isotope fractionation during basalt differentiation: Implications for a chondritic composition of the terrestrial mantle

    Science.gov (United States)

    Teng, F.-Z.; Wadhwa, M.; Helz, R.T.

    2007-01-01

    To investigate whether magnesium isotopes are fractionated during basalt differentiation, we have performed high-precision Mg isotopic analyses by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) on a set of well-characterized samples from Kilauea Iki lava lake, Hawaii, USA. Samples from the Kilauea Iki lava lake, produced by closed-system crystal-melt fractionation, range from olivine-rich cumulates to highly differentiated basalts with MgO content ranging from 2.37 to 26.87??wt.%. Our results demonstrate that although these basalts have diverse chemical compositions, mineralogies, crystallization temperatures and degrees of differentiation, their Mg isotopic compositions display no measurable variation within the limits of our external precision (average ??26Mg = - 0.36 ?? 0.10 and ??25Mg = - 0.20 ?? 0.07; uncertainties are 2SD). This indicates that Mg isotopic fractionation during crystal-melt fractionation at temperatures of ??? 1055????C is undetectable at the level of precision of the current investigation. Calculations based on our data suggest that at near-magmatic temperatures the maximum fractionation in the 26Mg/24Mg ratio between olivine and melt is 0.07???. Two additional oceanic basalts, two continental basalts (BCR-1 and BCR-2), and two primitive carbonaceous chondrites (Allende and Murchison) analyzed in this study have Mg isotopic compositions similar to the Kilauea Iki lava lake samples. In contrast to a recent report [U. Wiechert, A.N. Halliday, Non-chondritic magnesium and the origins of the inner terrestrial planets, Earth and Planetary Science Letters 256 (2007) 360-371], the results presented here suggest that the Bulk Silicate Earth has a chondritic Mg isotopic composition. ?? 2007.

  2. Can Halogen Enrichment in Reduced Enstatite Chondrites Provide Clues to Volatile Accretion in the Early Earth?

    Science.gov (United States)

    Clay, P. L.; Burgess, R.; Busemann, H.; Ruzié, L.; Joachim, B.; Ballentine, C.

    2013-12-01

    Understanding how the Earth obtained and ultimately retained its volatiles is important for our overall understanding of large scale planetary evolution. Numerous models exist for the heterogeneous accretion of volatiles to early Earth, but accounting for all elements through accretion of typical planetary building blocks (e.g., CI chondrites) is difficult. Proto-planetary collisions resulting in the accretion of volatile-poor material under reducing conditions followed by accretion of volatile-rich material under oxidizing conditions has been suggested in such models [e.g., 1]. The heavy halogens (Cl, Br and I), a group of moderately volatile elements, are excellent tracers of planetary processing due to their low abundance and incompatible nature. Therefore characterizing halogen abundance and distribution in materials that accreted to form the planets, e.g., primitive meteorites, is crucial. One group of primitive meteorites, the enstatite chondrites (EC's), are amongst the most reduced materials in the solar system as evidenced by their unique mineral assemblage. Yet despite forming under ultra-reducing conditions, they are enriched in the moderately volatile elements, such as the halogens. The ECs are of particular interest owing to their oxygen isotopic composition which plots along the terrestrial fractionation line, linking them isotopically to the Earth-Moon system. These samples can thus potentially provide clues on the accretion of moderately volatile element rich material under reducing conditions, such as it may have existed during the early stages of Earth's accretion. Chlorine, Br and I concentrations in ECs were determined through step-heating small neutron-irradiated samples (0.3 to 3.3 mg) and measured by mass spectrometry using the noble gas proxy isotopes 38ArCl/Cl, 80KrBr/Br and 128XeI/I. The EH chondrites are consistently enriched in the heavy halogens (up to 330 ppm Cl, 2290 ppb Br and 180 ppb I), compared to other ordinary and carbonaceous

  3. Diamond thermoluminescence properties of different chondrites

    Science.gov (United States)

    Fisenko, A. V.; Kashkarov, L. L.; Semjonova, L. F.; Pillinger, C. T.

    1993-01-01

    It was found that thermoluminescence (TL) glows of diamonds depend on the origin of diamonds and the chondrite metamorphism degree. The investigation of TL of diamonds was continued and the results for diamonds from Murchison CM2, Krymka LL3.0, Kainsaz CO3, and Abee E4 were considered. The diamonds synthesized by CVD-process (samples 133, 159) and by detonation from soot (DDS-B14-89) were also analyzed for comparison. Before the TL measuring samples were annealed at approximately 350 C for a few seconds and then irradiated by gamma-rays of Cs-137 up to dose approximately 200 krad. TL-measurements were performed in the air atmosphere on the standard equipment. TL data for samples are shown. TL glow for some diamonds are also presented.

  4. The thermoluminescence carrier in the Dhajala chondrite

    Science.gov (United States)

    Sparks, M. H.; Mckimmey, P. M.; Sears, D. W. G.

    1983-01-01

    It is pointed out that the type 3 (unequilibrated) ordinary chondrites provide a major source of information on the early solar system. However, the interpretation of the data is difficult because all but a few display signs of metamorphic alteration. The present investigation is concerned with the thermoluminescence (TL) sensitivity measurements on 58 chondrules separated from the Dhajala meteorites. The data were discussed briefly by Sparks and Sears (1982). In the current investigation particular attention is given to the constraints placed by these data on the mechanism by which metamorphism is related to TL sensitivity. Dhajala-normalized TL sensitivity of the separated chondrules is plotted against chondrule mass, and a histogram of the CaO contents of 15 chondrules is presented. Histograms showing the TL sensitivity of chondrules separated from the Dhajala meteorite are also provided.

  5. Toward an Astrophysical Theory of Chondrites

    Science.gov (United States)

    Shang, Hsien; Shu, Frank H.; Lee, Typhoon

    1996-01-01

    Sunlike stars are born with disks. Based on our recently developed model to understand how a magnetized new star interacts with its surrounding accretion disk, we advanced an astrophysical theory for the early solar system. The aerodynamic drag of a magnetocentrifugally driven wind out of the inner edge of a shaded disk could expose solid bodies lifted into the heat of direct sunlight, when material is still accreting onto the protosun. Chondrules, calcium-aluminum-rich inclusions (CAI's), and rims could form along the flight for typical self-consistent parameters of the outflow in different stages of star formation. The process gives a natural sorting mechanism that explains the size distribution of CAI's and chondrules, as well as their associated rims. Chondritic bodies then subsequently form by compaction of the processed solids with the ambient nebular dust comprising the matrices after their reentry at great distances from the original launch radius.

  6. Identification of a Compound Spinel and Silicate Presolar Grain in a Chondritic Interplanetary Dust Particle

    Science.gov (United States)

    Nguyen, A. N.; Nakamura-Messenger, K.; Messenger, S.; Keller, L. P.; Kloeck, W.

    2014-01-01

    Anhydrous chondritic porous interplanetary dust particles (CP IDPs) have undergone minimal parent body alteration and contain an assemblage of highly primitive materials, including molecular cloud material, presolar grains, and material that formed in the early solar nebula [1-3]. The exact parent bodies of individual IDPs are not known, but IDPs that have extremely high abundances of presolar silicates (up to 1.5%) most likely have cometary origins [1, 4]. The presolar grain abundance among these minimally altered CP IDPs varies widely. "Isotopically primitive" IDPs distinguished by anomalous bulk N isotopic compositions, numerous 15N-rich hotspots, and some C isotopic anomalies have higher average abundances of presolar grains (375 ppm) than IDPs with isotopically normal bulk N (<10 ppm) [5]. Some D and N isotopic anomalies have been linked to carbonaceous matter, though this material is only rarely isotopically anomalous in C [1, 5, 6]. Previous studies of the bulk chemistry and, in some samples, the mineralogy of select anhydrous CP IDPs indicate a link between high C abundance and pyroxene-dominated mineralogy [7]. In this study, we conduct coordinated mineralogical and isotopic analyses of samples that were analyzed by [7] to characterize isotopically anomalous materials and to establish possible correlations with C abundance.

  7. I-Xe Dating: The Time Line of Chondrule Formation and Metamorphism in LL Chondrites

    Science.gov (United States)

    Pravdivtseva, O. V.; Hohenberg, C. M.; Meshik, A. P.

    2005-01-01

    Refractory inclusions, considered to be the oldest solids formed in the solar nebula. (4567.2 0.6 Ma) [1], are common in many carbonaceous and in some ordinary and enstatite chondrites. High-precision Pb- Pb ages for CAI s and chondrules (from different meteorites) suggested that chondrule formation appeared to have started about 2 Ma later than that of CAIs [1]. However, recent 26Al/26Mg data suggest simultaneous formation of CAI s and chondrules in Allende [2]. The I-Xe ages of CAI s in Allende are about 2 Ma younger than the I-Xe ages of Allende chondrules [3] but, like all chronometers, the I-Xe system records closure time of its particular host phase. In the case of Allende CAI s, the major iodine-bearing phase is sodalite, a secondary phase presumably formed by aqueous alteration, so I-Xe reflects the post-formational processes in these objects. In chondrules the iodine host phases vary and can reflect formation and/or alteration but, to put chondrule ages on a quantative basis, some problems should first be addressed.

  8. Multiple and Fast: The Accretion of Ordinary Chondrite Parent Bodies

    CERN Document Server

    Vernazza, P; Binzel, R P; Hiroi, T; DeMeo, F E; Birlan, M; Hewins, R; Ricci, L; Barge, P; Lockhart, M

    2014-01-01

    Although petrologic, chemical and isotopic studies of ordinary chondrites and meteorites in general have largely helped establish a chronology of the earliest events of planetesimal formation and their evolution, there are several questions that cannot be resolved via laboratory measurements and/or experiments only. Here we propose rationale for several new constraints on the formation and evolution of ordinary chondrite parent bodies (and by extension most planetesimals) from newly available spectral measurements and mineralogical analysis of main belt S-type asteroids (83 objects) and unequilibrated ordinary chondrite meteorites (53 samples). Based on the latter, we suggest spectral data may be used to distinguish whether an ordinary chondrite was formed near the surface or in the interior of its parent body. If these constraints are correct, the suggested implications include that: i) large groups of compositionally similar asteroids are a natural outcome of planetesimal formation and, consequently, meteor...

  9. Characterization of Luminescent Minerals in CM2 Chondrite (Jbilet Winselwan)

    Science.gov (United States)

    Kiku, Y. K.; Ohgo, S. O.; Nishido, H. N.

    2014-09-01

    We have characterized luminescent minerals of forsterite, diopside and spinel in the CM2 chondrite (Jbilet Winselwan) using SEM-CL and to discuss the formation of the luminescent minerals under aqueous conditions.

  10. A Common Parent for IIE Iron Meteorite and H Chondrites

    Science.gov (United States)

    Teplyakova, S. N.; Humayun, M.; Lorenz, C. A.; Ivanova, M. A.

    2012-03-01

    We report new siderophile element abundances for the metal in the IIE irons — Watson, Tobychan, Elga, Verkhne Dnieprovsk, and Miles — to examine the possible genetic relations between IIE metal and H chondritic precursors.

  11. Ruthenium Isotopic Composition of Terrestrial Materials, Iron Meteorites and Chondrites

    Science.gov (United States)

    Becker, H.; Walker, R. J.

    2002-01-01

    Ru isotopic compositions of magmatic iron meteorites and chondrites overlap with terrestrial Ru at the 0.3 to 0.9 (epsilon) level. Additional information is contained in the original extended abstract.

  12. Rare Earth Element Complementarity in CO and CV Chondrites

    Science.gov (United States)

    Crapster-Pregont, E. J.; Friedrich, J. M.; Ebel, D. S.

    2014-09-01

    LREE/HREE ratios in each component of CO and CV chondrites combine to produce complementary, flat bulk REE pattern, while individually yielding insight into mineral controls and precursor characteristics.

  13. New Insight into the Solar System’s Transition Disk Phase Provided by the Metal-rich Carbonaceous Chondrite Isheyevo

    Science.gov (United States)

    Morris, Melissa A.; Garvie, Laurence A. J.; Knauth, L. Paul

    2015-03-01

    Many aspects of planet formation are controlled by the amount of gas remaining in the natal protoplanetary disks (PPDs). Infrared observations show that PPDs undergo a transition stage at several megayears, during which gas densities are reduced. Our Solar System would have experienced such a stage. However, there is currently no data that provides insight into this crucial time in our PPD’s evolution. We show that the Isheyevo meteorite contains the first definitive evidence for a transition disk stage in our Solar System. Isheyevo belongs to a class of metal-rich meteorites whose components have been dated at almost 5 Myr after formation of Ca, Al-rich inclusions, and exhibits unique sedimentary layers that imply formation through gentle sedimentation. We show that such layering can occur via the gentle sweep-up of material found in the impact plume resulting from the collision of two planetesimals. Such sweep-up requires gas densities consistent with observed transition disks (10-12-10-11 g cm-3). As such, Isheyevo presents the first evidence of our own transition disk and provides new constraints on the evolution of our solar nebula.

  14. Chiral Biomarkers and Microfossils in Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2010-01-01

    Homochirality of the biomolecules (D-sugars of DNA and RNA and L-amino acids of proteins) is a fundamental property of all life on Earth. Abiotic mechanisms yield racemic mixtures (D/L=1) of chiral molecules and after the death of an organism, the enantiopure chiral biomolecules slowly racemize. Several independent investigators have now established that the amino acids present in CI1 and CM2 carbonaceous meteorites have a moderate to strong excess of the L-enantiomer. Stable isotope data have established that these amino acids are both indigenous and extraterrestrial. Carbonaceous meteorites also contain many other strong chemical biomarkers including purines and pyrimidines (nitrogen heterocycles of nucleic acids); pristine and phytane (components of the chlorophyll pigment) and morphological biomarkers (microfossils of filamentous cyanobacteria). Energy dispersive X-ray Spectroscopy (EDS) analysis reveals that nitrogen is below the detectability level in most of the meteorite filaments as well as in Cambrian Trilobites and filaments of 2.7 Gya Archaean cyanobacteria from Karelia. The deficiency of nitrogen in the filaments and the total absence of sugars, of twelve of the life-critical protein amino acids, and two of the nucleobases of DNA and RNA provide clear and convincing evidence that these filaments are not modern biological contaminants. This paper reviews the chiral, chemical biomarkers morphological biomarkers and microfossils in carbonaceous meteorites. This paper reviews chiral and morphological biomarkers and discusses the missing nitrogen, sugars, protein amino acids, and nucleobases as ?bio-discriminators? that exclude modern biological contaminants as a possible explanation for the permineralized cyanobacterial filaments found in the meteorites.

  15. Microfossils in CI and CO Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.; Rozanov, Alexei Y.; Jerman, Gregory; Costen, James

    2003-01-01

    Secondary and backscatter electron images and x-ray spectral data of selected CI (Alais, Orgueil, and Tagish Lake) and CO3 (Rainbow and Dar a1 Gani 749) carbonaceous meteorites have recently been obtained using Field Emission and Environmental Scanning Electron Microscopes These studies indicate the presence of a large assemblage of biomarkers and complex lithified and carbonized remains of bodies that we interpret as indigenous microfossils. We discuss the meteorites, provide images of many of the biogenic forms found embedded in the freshly fractured meteorite surfaces.

  16. Chemical and physical studies of type 3 chondrites 12: The metamorphic history of CV chondrites and their components

    Science.gov (United States)

    Guimon, R. Kyle; Symes, Steven J. K.; Sears, Derek W. G.

    1995-01-01

    The induced thermoluminescence (TL) properties of 16 CV and CV-related chondrites, four CK chondrites and Renazzo (CR2) have been measured in order to investigate their metamorphic history. The petrographic, mineralogical and bulk compositional differences among the CV chondrites indicate that the TL sensitivity of the approximately 130 C TL peak is reflecting the abundance of ordered feldspar, especially in chondrule mesostasis, which in turn reflects parent-body metamorphism. The TL properties of 18 samples of homogenized Allende powder heated at a variety of times and temperatures, and cathodoluminescence mosaics of Axtell and Coolidge, showed results consistent with this conclusion. Five refractory inclusions from Allende, and separates from those inclusions, were also examined and yielded trends reflecting variations in mineralogy indicative of high peak temperatures (either metamorphic or igneous) and fairly rapid cooling. The CK chondrites are unique among metamorphosed chondrites in showing no detectable induced TL, which is consistent with literature data that suggests very unusual feldspar in these meteorites. Using TL sensitivity and several mineral systems and allowing for the differences in the oxidized and reduced subgroups, the CV and CV-related meteorites can be divided into petrologic types analogous to those of the ordinary and CO type 3 chondrites. Axtell, Kaba, Leoville, Bali, Arch and ALHA81003 are type 3.0-3.1, while ALH84018, Efremovka, Grosnaja, Allende and Vigarano are type 3.2-3.3 and Coolidge and Loongana 001 are type 3.8. Mokoia is probably a breccia with regions ranging in petrologic type from 3.0 to 3.2. Renazzo often plots at the end of the reduced and oxidized CV chondrite trends, even when those trends diverge, suggesting that in many respects it resembles the unmetamorphosed precursors of the CV chondrites. The low-petrographic types and low-TL peak temperatures of all samples, including the CV3.8 chondrites, indicates metamorphism

  17. Keto-acids in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, G.; Chang, P. M.; Dugas, A.; Byrd, A.; Chang, P. M.; Washington, N.

    2005-01-01

    The Murchison and Murray meteorites are the best-characterized carbonaceous meteorites with respect to organic chemistry and are generally used as references for organic compounds in extraterrestrial material. Among the classes of organic compounds found in these meteorites are amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Such compounds, important in contemporary biochemistry, are thought to have been delivered to the early Earth in asteroids and comets and may have played a role in early life and/or the origin of life. Absent among (today's) critically important biological compounds reported in carbonaceous meteorites are keto acids, i.e., pyruvic acid, acetoacetic acid, and higher homologs. These compounds are key intermediates in such critical processes as glycolysis and the citric acid cycle. In this study several individual meteoritic keto acids were identified by gas chromatography-mass spectrometry (GC-MS) (see figure below). All compounds were identified as their trimethylsilyl (TMS), isopropyl ester (ISP), and tert-butyldimethylsilyl (tBDMS) derivatives. In general, the compounds follow the abiotic synthesis pattern of other known meteorite classes of organic compounds [1,2]: a general decrease in abundance with increasing carbon number within a class of compounds and many, if not all, possible isomers present at a given carbon number. The majority of the shown compounds was positively identified by comparison of their mass spectra to commercially available standards or synthesized standards.

  18. Characterization of carbonaceous particles from lake sediments

    International Nuclear Information System (INIS)

    Spheroidal carbonaceous particles produced by high temperature combustion of coal and oil were found in high concentrations in lake sediments from areas of high acid deposition. The sediment record of these particles showing the onset of industrialisation correlates well with the record of acidification as indicated by diatom analysis. To find sources of the atmospheric deposition affecting a lake and its catchment, characterisation of the carbonaceous particles is necessary. A reference data set of particle chemistries from coal and oil power stations was produced using EDS generated data of 17 elements. Using multivariate statistical techniques, the most important elements for the coal/oil separation were identified and incorporated into a linear discriminant function which allocated fuel type with > 97% accuracy. Application of this technique to surface sediments in Scotland shows the influence of oil burning from outside the region. When applied to a full sediment core, the history of coal and oil combustion affecting the lake is seen and correlates well with known coal and oil consumption figures. Consequently this method could be used to add extra dating levels to sediment cores. The technique has been extended to include peat particles and could potentially be used on those from brown coal, lignite and oil shale combustion

  19. Calcium-aluminum-rich inclusions from enstatite chondrites: indigenous or foreign?

    Science.gov (United States)

    Guan; Huss; MacPherson; Wasserburg

    2000-08-25

    The primary mineral assemblages and initial (26)Al/(27)Al ratios of rare calcium-aluminum-rich inclusions (CAIs) from enstatite (E) chondrites are similar to those of CAIs from other chondrite classes. CAIs from all chondrite classes formed under oxidizing conditions that are much different from the reducing conditions under which the E chondrites formed. Either CAIs formed at an earlier, more oxidizing epoch in the region where E chondrites ultimately formed, or they formed at a different place in the solar nebula and were transported into the E chondrite formation region. PMID:10958775

  20. Enantiomeric excesses of chiral amines in ammonia-rich carbonaceous meteorites

    Science.gov (United States)

    Pizzarello, Sandra; Yarnes, Christopher T.

    2016-06-01

    Chiral homogeneity is essential to the structure and function of terrestrial biopolymers but the origin of this "homochirality" is poorly understood and remains one of the many unknowns surrounding the origins of life. Several amino acids extracted from Carbonaceous Chondrite meteorites display L-enantiomeric excesses (ee) and their findings have encouraged suggestions that an input of non-racemic meteoritic compounds to early Earth might have led to terrestrial homochirality. Motivated by occasional indications of possible ee in other classes of soluble meteoritic compounds, we have undertaken a systematic study of the chiral distribution of amines in Renazzo-type (CR) meteorites, where they are the second most abundant organic molecular species and ammonia is by far the most abundant single molecule. We report here the first time finding of L-ee for two chiral amines in several pristine CR meteorites from Antarctica and outline a proposal by which the compounds possibly formed from the same ketone precursors as some of the chiral amino acids. This would occur during a warm hydrous stage of the asteroidal parent body, via a reductive amination process in the presence of a large abundance of ammonia, where the precursors' adsorption upon mineral phases possessing asymmetry offered the opportunity for chiral induction. Because the precursor ketones are achiral, the proposal underscores the likelihood of diverse asymmetric influences and processes in cosmochemistry.

  1. Global cloud condensation nuclei influenced by carbonaceous combustion aerosol

    Science.gov (United States)

    Spracklen, D. V.; Carslaw, K. S.; Pöschl, U.; Rap, A.; Forster, P. M.

    2011-09-01

    Black carbon in carbonaceous combustion aerosol warms the climate by absorbing solar radiation, meaning reductions in black carbon emissions are often perceived as an attractive global warming mitigation option. However, carbonaceous combustion aerosol can also act as cloud condensation nuclei (CCN) so they also cool the climate by increasing cloud albedo. The net radiative effect of carbonaceous combustion aerosol is uncertain because their contribution to CCN has not been evaluated on the global scale. By combining extensive observations of CCN concentrations with the GLOMAP global aerosol model, we find that the model is biased low (normalised mean bias = -77 %) unless carbonaceous combustion aerosol act as CCN. We show that carbonaceous combustion aerosol accounts for more than half (52-64 %) of global CCN with the range due to uncertainty in the emitted size distribution of carbonaceous combustion particles. The model predicts that wildfire and pollution (fossil fuel and biofuel) carbonaceous combustion aerosol causes a global mean cloud albedo aerosol indirect effect of -0.34 W m-2, with stronger cooling if we assume smaller particle emission size. We calculate that carbonaceous combustion aerosol from pollution sources cause a global mean aerosol indirect effect of -0.23 W m-2. The small size of carbonaceous combustion particles from fossil fuel sources means that whilst pollution sources account for only one-third of the emitted mass they cause two-thirds of the cloud albedo aerosol indirect effect that is due to carbonaceous combustion aerosol. This cooling effect must be accounted for, along with other cloud effects not studied here, to ensure that black carbon emissions controls that reduce the high number concentrations of fossil fuel particles have the desired net effect on climate.

  2. Cloud albedo increase from carbonaceous aerosol

    Directory of Open Access Journals (Sweden)

    W. R. Leaitch

    2010-08-01

    Full Text Available Airborne measurements from two consecutive days, analysed with the aid of an aerosol-adiabatic cloud parcel model, are used to study the effect of carbonaceous aerosol particles on the reflectivity of sunlight by water clouds. The measurements, including aerosol chemistry, aerosol microphysics, cloud microphysics, cloud gust velocities and cloud light extinction, were made below, in and above stratocumulus over the northwest Atlantic Ocean. On the first day, the history of the below-cloud fine particle aerosol was marine and the fine particle sulphate and organic carbon mass concentrations measured at cloud base were 2.4 μg m−3 and 0.9 μg m−3 respectively. On the second day, the below-cloud aerosol was continentally influenced and the fine particle sulphate and organic carbon mass concentrations were 2.3 μg m−3 and 2.6 μg m−3 respectively. Over the range 0.06–0.8 μm diameter, the shapes of the below-cloud size distributions were similar on both days and the number concentrations were approximately a factor of two higher on the second day. The cloud droplet number concentrations (CDNC on the second day were approximately three times higher than the CDNC measured on the first day. Using the parcel model to separate the influence of the differences in gust velocities, we estimate from the vertically integrated cloud light scattering measurements a 6% increase in the cloud albedo principally due to the increase in the carbonaceous components on the second day. Assuming no additional absorption by this aerosol, a 6% albedo increase translates to a local daytime radiative cooling of ∼12 W m−2. This result provides observational evidence that the role of anthropogenic carbonaceous components in the cloud albedo effect can be much larger than that of anthropogenic sulphate, as some global simulations have indicated.

  3. Microfossils of Cyanobacteria in Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2007-01-01

    During the past decade, Environmental and Field Emission Scanning Electron Microscopes have been used at the NASA/Marshall Space Flight Center to investigate freshly fractured interior surfaces of a large number of different types of meteorites. Large, complex, microfossils with clearly recognizable biological affinities have been found embedded in several carbonaceous meteorites. Similar forms were notably absent in all stony and nickel-iron meteorites investigated. The forms encountered are consistent in size and morphology with morphotypes of known genera of Cyanobacteria and microorganisms that are typically encountered in associated benthic prokaryotic mats. Even though many coccoidal and isodiametric filamentous cyanobacteria have a strong morphological convergence with some other spherical and filamentous bacteria and algae, many genera of heteropolar cyanobacteria have distinctive apical and basal regions and cellular differentiation that makes it possible to unambiguously recognize the forms based entirely upon cellular dimensions, filament size and distinctive morphological characteristics. For almost two centuries, these morphological characteristics have historically provided the basis for the systematics and taxonomy of cyanobacteria. This paper presents ESEM and FESEM images of embedded filaments and thick mats found in-situ in the Murchison CM2 and Orgueil cn carbonaceous meteorites. Comparative images are also provided for known genera and species of cyanobacteria and other microbial extremophiles. Energy Dispersive X-ray Spectroscopy (EDS) studies indicate that the meteorite filaments typically exhibit dramatic chemical differentiation with distinctive difference between the possible microfossil and the meteorite matrix in the immediate proximity. Chemical differentiation is also observed within these microstructures with many of the permineralized filaments enveloped within electron transparent carbonaceous sheaths. Elemental distributions of

  4. Photolytic process for gasification of carbonaceous material

    International Nuclear Information System (INIS)

    Process and apparatus are disclosed for converting carbon dioxide to carbon monoxide by subjecting the carbon dioxide to radiation in the presence of carbonaceous material such as coal to form carbon monoxide. The preferred form of radiation is solar energy, and the process is preferably carried out in an atmosphere essentially free of oxygen. The invention also includes subjecting carbon monoxide to radiation to form purified carbon and useful heat energy. The two procedures can be combined into a single process for converting solar or other energy into useful thermal energy with the production of useful products. The reactor apparatus is specifically designed to carry out the radiation-induced conversions. Coal can be desulfurized and its caking characteristics altered by solar radiation in the presence of suitable gases. 3 figures

  5. Relationship between carbonaceous rocks and uranium mineralization

    International Nuclear Information System (INIS)

    The relationship between carboniferous materials in the rocks and the formation of hydrothermal uranium mineralization has been discussed with the example of super-large hydrothermal uranium deposits (such as Canada's Athabasca, Australia's East Alligator River, Germany's Schlema-Alberoda and Roenneberg, Gabon's Franceville). According to the thermodynamic data, it has been emphasized that the interaction between carbon and water causes the formation of gaseous reductants (such as CO2, CO, H2 and CH4) under the condition of higher temperature and lower pressure. It has been indicated that CH4 should be the main gaseous reductants under the temperature (150-200 degree C) and pressure (50-100 MPa) which are suitable to the uranium metallogenesis. This conclusion accords with the practical situation observed in the deposits mentioned above, at the same time disaffirms the traditional points of view that the carbonaceous rocks can be the uranium sources during the formation of hydrothermal uranium deposits. (authors)

  6. Ordinary Chondrite Formation from two Components: Implied Connection to Planet Mercury

    OpenAIRE

    Herndon, J. Marvin

    2004-01-01

    Major element fractionation among chondrites has been discussed for decades as ratios relative to Si or Mg. Expressing ratios relative to Fe leads to a new relationship admitting the possibility that ordinary chondrite meteorites are derived from two components: one is a relatively undifferentiated, primitive component, oxidized like the CI or C1 chondrites; the other is a somewhat differentiated, planetary component, with oxidation state like the reduced enstatite chondrites. Such a picture ...

  7. Chondritic xenon in the Earth's mantle.

    Science.gov (United States)

    Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G; Füri, Evelyn; Marty, Bernard

    2016-05-01

    Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth's mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth's mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth's accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion. PMID:27111512

  8. The Origin of Chondrites: Metal-Silicate Separation Experiments Under Microgravity Conditions, Experiment 2

    Science.gov (United States)

    Moore, S. R.; Franzen, M.; Benoit, P. H.; Sears, D. W. G.; Holley, A.; Myers, M.; Godsey, R.; Czlapinski, J.

    2003-01-01

    Chondrites are categorized into different groups by several properties, including the metal-to-silicate ratio. Various processes have been suggested to produce distinct metal/silicate ratios, some based on sorting in the early solar nebular and others occurring after accretion on the parent body. Huang et al. suggested that a weak gravitational field accompanied by degassing, could result in metal/silicate separation on parent bodies. We suggest that asteroids were volatile-rich, at least early in their histories. Spectroscopic evidence from asteroid surfaces indicates that one-third of all asteroids maybe rich in clays and hydrated minerals, similar to carbonaceous chondrites. Internal and/or external heating could have caused volatiles to evaporate and pass through a surface dust layer. Spacecraft images of asteroids show they have a thick regoliths. Housen, and Asphaug and Nolan proposed that even a 10 km diameter asteroid could potentially have a significant regolith. Grain size and grain density sorting could occur in the unconsolidated layer by the process known as fluidization. This process occurs when an upward stream of gas is passed through a bed of particles which are lifted against a gravitational force. Fluidization is commonly used commercially to sort particulates. This type of behavior is based upon the bed, as a whole, and differs from aerodynamic sorting. Two sets of reduced gravity experiments were conducted during parabolic flights aboard NASA's KC-135 aircraft. The first experiment employed 310 tubes of 2.5 cm diameter, containing mixtures of sand and metal grains. A gas source was used to fluidize the mixture at reduced gravity conditions and mixtures were analyzed after the flight. However, this experiment did not allow a description of the fluidization as a function of gravity. A second experiment was conducted on the KC-135 aircraft in the summer of 2001, consisting of two Plexiglas cylinders containing a metal/silicate mixture, and video

  9. Rapid Classification of Ordinary Chondrites Using Raman Spectroscopy

    Science.gov (United States)

    Fries, M.; Welzenbach, L.

    2014-01-01

    Classification of ordinary chondrites is typically done through measurements of the composition of olivine and pyroxenes. Historically, this measurement has usually been performed via electron microprobe, oil immersion or other methods which can be costly through lost sample material during thin section preparation. Raman microscopy can perform the same measurements but considerably faster and with much less sample preparation allowing for faster classification. Raman spectroscopy can facilitate more rapid classification of large amounts of chondrites such as those retrieved from North Africa and potentially Antarctica, are present in large collections, or are submitted to a curation facility by the public. With development, this approach may provide a completely automated classification method of all chondrite types.

  10. Petrology of Two Itokawa Particles: Comparison with Equilibrated LL Chondrites

    Science.gov (United States)

    Komatsu, M.; Mikouchi, T.; Arai, T.; Fagan, T. J.; Zolensky, M.; Hagiya, K.; Ohsumi, K.; Karouji, Y.

    2015-01-01

    A strong link between Itokawa particles and LL chondrites was confirmed by preliminary examinations of Hayabusa particles [e.g., 1, 2]. Both poorly equilibrated and highly equilibrated particles have been found among the grains returned from Itokawa [1], and it is suggested that they correspond to LL4 and LL5-6, respectively. Here we report the petrography of two Itokawa particles and TEM study of one, and compare them to Antarctic LL chondrites with variable petrologic types (LL4-LL7) in order to understand the metamorphic history of asteroid Itokawa.

  11. TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2012-03-01

    Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

  12. Correlations and zoning patterns of phosphorus and chromium in olivine from H chondrites and the LL chondrite Semarkona

    Science.gov (United States)

    McCanta, M. C.; Beckett, J. R.; Stolper, E. M.

    2016-03-01

    Phosphorus zoning is observed in olivines in high-FeO (type IIA) chondrules in H chondrites over the entire range of petrologic grades: H3.1-H6. Features in P concentrations such as oscillatory and sector zoning, and high P cores are present in olivines that are otherwise unzoned in the divalent cations. Aluminum concentrations are low and not significantly associated with P zoning in chondrule olivines. In highly unequilibrated H chondrites, phosphorus zoning is generally positively correlated with Cr. Atomic Cr:P in olivine is roughly 1:1 (3:1 for one zone in one olivine in RC 075), consistent with Cr3+ charge-balancing P5+ substituting for Si4+. Normal igneous zonation involving the dominant chrome species Cr2+ was observed only in the LL3.0 chondrite Semarkona. In more equilibrated chondrites (H3.5-H3.8), Cr spatially correlated with P is occasionally observed but it is diffuse relative to the P zones. In H4-H6 chondrites, P-correlated Cr is absent. One signature of higher metamorphic grades (≥H3.8) is the presence of near matrix olivines that are devoid of P oscillatory zoning. The restriction to relatively high metamorphic grade and to grains near the chondrule-matrix interface suggests that this is a response to metasomatic processes. We also observed P-enriched halos near the chondrule-matrix interface in H3.3-H3.8 chondrites, likely reflecting the loss of P and Ca from mesostasis and precipitation of Ca phosphate near the chondrule surface. These halos are absent in equilibrated chondrites due to coarsening of the phosphate and in unequilibrated chondrites due to low degrees of metasomatism. Olivines in type IA chondrules show none of the P-zoning ubiquitous in type IIA chondrules or terrestrial igneous olivines, likely reflecting sequestration of P in reduced form within metallic alloys and sulfides during melting of type IA chondrules.

  13. Carbonaceous aerosols in Norwegian urban areas

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2009-03-01

    Full Text Available Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5 concentrations of elemental carbon (EC, organic carbon (OC, water-insoluble organic carbon (WINSOC, and water-soluble organic carbon (WSOC are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan.

    Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp at the suburban site was equal to (for PM10 or even higher (for PM2.5 than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3. This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM

  14. Carbonaceous deposits in direct utilization hydrocarbon SOFC anode

    Science.gov (United States)

    He, Hongpeng; Vohs, John M.; Gorte, Raymond J.

    Carbonaceous deposits formed in Cu-based SOFC anode compartment by exposing porous YSZ anodes to n-butane at elevated temperatures were studied using a combination of V- I curves, impedance spectroscopy, SEM, and TPO measurements. While short-term exposure of a porous YSZ matrix to n-butane at 973 K resulted in the deposition of electronically conducting carbonaceous film and therefore to enhance the fuel cell performance, the power density decays quickly in n-butane at temperature 1073 K or higher for long-term operation. SEM results indicate that the carbonaceous deposits arising from gas phase reaction have different morphology, and a dense layer composed of poly-aromatic rings has been formed on the porous anode surface. The dense layer could block the penetration of fuels to the anode and ions transfer to the three-phase boundaries where electrochemical reactions occur, resulting in the drop of the power density. TPO measurements revealed that the amount of carbonaceous deposits increased and the type of deposits changed with exposure time to n-butane. The stability of deposits increased with extending the exposure time according to the increased oxidation temperature. Steam can remove the carbonaceous deposits from the porous YSZ anode, but the reaction temperature was severely elevated compared to that of oxygen. The carbonaceous deposits can also be removed at 973 K by steam but the deposition of carbon will be controlled by the speed of removal and formation from the gas phase reaction.

  15. An interplanetary dust particle with links to CI chondrites

    Science.gov (United States)

    Keller, Lindsay P.; Thomas, Kathie L.; Mckay, David S.

    1992-01-01

    W7013F5 is a chondritic, hydrated interplanetary dust particle whose composition and mineralogy is nearly identical to that found in the CI chondrites. Transmission electron microscope observations show that the phyllosilicates in W7013F5 consist largely of a coherent undergrowth of Mg-Fe serpentine and Fe-bearing saponite on the unitcell scale. This distinctive intergrowth of phyllosilicates has only been observed previously in the CI chondrites. Other secondary minerals in W7013F5 include Mg-Fe carbonates, magnetite, and pentlandite. The mineral assemblage in W7013F5 is generally not as oxidized as that in the CI chondrites. The presence of kamacite in W7013F5 indicates that the particle is extraterrestrial, and a thin amorphous rim surrounding the particle provides evidence that it is not a piece of a meteorite that fragmented during transit through the atmosphere. The apparent lack of hydrated IDPs with CI mineralogy and chemistry may indicate that CI-type dust-producing asteroids are uncommon in the asteroid belt.

  16. Chondrules and Opaque Phases in Unequilibrated R Chondrites: A Comprehensive Assessment of Their Formation

    Science.gov (United States)

    Miller, K. E.; Lauretta, D. S.; Connolly, H. C., Jr.; Berger, E. L.; Domanik, K.

    2016-01-01

    Equilibrated Rumuruti (R) chondrites record an oxygen fugacity between 0 and 3.5 log units below the fayalite-magnetite-quartz buffer, and a sulfur fugacity (fS2) 2 log units above the iron-troilite buffer. They are more than an order of magnitude more oxidized than the ordinary chondrites [1], and orders of magnitude more sulfidized than solar values. Although the R chondrites have the highest (delta)O-17 value of any meteorites, analyses of unequilibrated R chondrites indicate chondrule formation in an oxygen isotope reservoir similar to that of the ordinary chondrite chondrules. We present the relationship of the R chondrite parent body to pre-accretionary volatiles O and S based on our analyses of unequilibrated R chondrite material in two thin sections from the meteorite Mount Prestrud (PRE) 95404.

  17. Characterization of carbonaceous aerosols in urban air

    Science.gov (United States)

    Husain, Liaquat; Dutkiewicz, Vincent A.; Khan, A. J.; Ghauri, Badar M.

    Concentrations of black carbon, [BC], were determined with an Aethalometer every 5 min at Lahore, a city of about 10 million in Pakistan, from 22 November 2005 to 31 January 2006. [BC] were very high, ranging from about 5 to 110μgm-3, with a mean of 21.7μgm-3. A distinct diurnal variation was observed: concentrations were lowest from about 10 a.m. to 4 p.m. local time (LT), and highest around 5-9 p.m. No clear relationship was observed between surface wind directions and [BC], although some of the highest concentrations were observed when the airflow was from southwest to northwest. The daily variations in concentrations were strongly affected by the diurnal variations in the mixing height; BC concentrations were low during the day when the mixing heights were high, ˜1000m, and very high at night when the mixing heights were low thermal-optical method. The [BC] were highly correlated with EC (r2=0.71), but on average 25% higher than [EC]. The [EC] and [OC] concentrations were moderately correlated (r2=0.65). The [OC]/[EC] ratios varied from 2.8 to 12, with a mean of 5.6. Although a large component of the carbonaceous aerosols in Lahore originated from fossil fuel combustion, a significant fraction was derived from biomass burning.

  18. Battery characteristics with various carbonaceous materials

    Science.gov (United States)

    Kuribayashi, Isao; Yokoyama, Mika; Yamashita, Masataka

    Various carbonaceous particles having a core-shell structure, produced from graphite and pseudo-graphite coated with pitchblended phenol resin and green mesophase-pitch coated with phenol resin and ground graphite powder, were investigated as active materials for negative electrodes. The particles with natural graphite cores, as well as those with pseudo-graphite cores, were stable both in 1 M LiClO 4sbnd PC:EC (50:50) electrolyte and in 1.5 M LiBF 4sbnd PC:EC:BL (25:25:50) electrolyte, and showed excellent electrical capacities. Those produced from green mesophase-pitch cores were of markedly deformed configuration and showed large capacity gains with only small additions of graphite powder to the phenol coating material. Negative electrodes, in which the particles containing natural graphites cores were blended with petroleum coke in various ratios, showed that it may be possible to produce cells with specific discharge voltage curves, by varying the ratio of this blend.

  19. Detection of carbonaceous material in Naga Bhasma

    Directory of Open Access Journals (Sweden)

    S K Singh

    2012-01-01

    Full Text Available Traditional medicines have maintained their popularity in all regions of the developing world and are being adopted increasingly by people worldwide. Indian traditional system of medicine Ayurveda make use of unique metallic-herbal preparations (called Bhasma which involves different processing steps including repeated steps of calcination of metal in the presence of natural precursor (herbal juices, decoctions, and powders, etc. It has been recently established that Bhasma contains nano/sub-micron size particles and different nutrient elements. However, the role and the end product of the raw materials, especially the herbal parts, used during the synthesis of the drug (Bhasma is one of the important but unanswered problems in such medicinal preparations. Present work on Naga Bhasma is an attempt to understand the role of natural precursors in detail. Our results on infrared, Raman and X-ray photoelectron spectroscopy along with thermal measurements identify the presence of carbonaceous material (hydrogenated amorphous carbon in the drug along with other compounds. In addition, this work also suggests the science and mechanism behind such complex preparations which could help in standardization of such medicines.

  20. Multiple and fast: The accretion of ordinary chondrite parent bodies

    International Nuclear Information System (INIS)

    Although petrologic, chemical, and isotopic studies of ordinary chondrites and meteorites in general have largely helped establish a chronology of the earliest events of planetesimal formation and their evolution, there are several questions that cannot be resolved via laboratory measurements and/or experiments alone. Here, we propose the rationale for several new constraints on the formation and evolution of ordinary chondrite parent bodies (and, by extension, most planetesimals) from newly available spectral measurements and mineralogical analysis of main-belt S-type asteroids (83 objects) and unequilibrated ordinary chondrite meteorites (53 samples). Based on the latter, we suggest that spectral data may be used to distinguish whether an ordinary chondrite was formed near the surface or in the interior of its parent body. If these constraints are correct, the suggested implications include that: (1) large groups of compositionally similar asteroids are a natural outcome of planetesimal formation and, consequently, meteorites within a given class can originate from multiple parent bodies; (2) the surfaces of large (up to ∼200 km) S-type main-belt asteroids mostly expose the interiors of the primordial bodies, a likely consequence of impacts by small asteroids (D < 10 km) in the early solar system; (3) the duration of accretion of the H chondrite parent bodies was likely short (instantaneous or in less than ∼105 yr, but certainly not as long as 1 Myr); (4) LL-like bodies formed closer to the Sun than H-like bodies, a possible consequence of the radial mixing and size sorting of chondrules in the protoplanetary disk prior to accretion.

  1. Surviving High-temperature Components in CI Chondrites

    Science.gov (United States)

    Zolensky, M.; Frank, D.

    2014-01-01

    The CI1 chondrites, while having the most solar-like compo-sition of any astromaterial available for laboratory analysis, have also been considerably altered by asteroidal processes including aqueous alteration. It is of fundamental importance to determine their pre-alteration mineralogy, so that the state of matter in the early Solar System can be better determined. In the course of a re-examination of the compositional range of olivine and low-Ca pyroxene in CI chondrites Orgueil, Ivuna and Alais [1] we found the first reported complete CAI, as already reported [2], with at-tached rock consisting mainly of olivine and low-Ca pyroxene. The range of residual olivine major element compositions we have determined in the CIs (Fig. 1) may now be directly com-pared with those of other astromaterials, including Wild 2 grains. The abundance of olivine and low-Ca pyroxene in CIs is higher than is generally appreciated, and in fact much higher than for some CMs [1]. We also noted numerous rounded objects varying in shape from spheres to oblate spheroids, and ranging up to 100µm in size (Fig. 2), which have been previously noted [3] but have not been well documented or appreciated. We characterized the mineralogy by transmission electron microscopy and found that they consist mainly of rather fine-grained, flaky single phase to intergrown serpentine and saponite. These two materials in fact dominate the bulk of the host CI1 chondrites. With the exception of sparse spinels, the rounded phyllosilicate objects are remarka-bly free of other minerals, suggesting that the precursor from which the phyllosilicates were derived was a homogeneous mate-rial. We suggest that these round phyllosilicates aggregates in CI1 chondrites were cryptocrystalline to glassy microchondrules. If so then CI chondrites cannot be considered chondrule-free. Small though they are, the abundance of these putative microchondrules is the same as that of chondrules in the Tagish Lake meteorite.

  2. Multiple and fast: The accretion of ordinary chondrite parent bodies

    Energy Technology Data Exchange (ETDEWEB)

    Vernazza, P.; Barge, P. [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Zanda, B.; Hewins, R. [Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Universités, Muséum National d' Histoire Naturelle, UPMC Université Paris 06, UMR CNRS 7590, IRD UMR 206, 61 rue Buffon, F-75005 Paris (France); Binzel, R. P.; DeMeo, F. E.; Lockhart, M. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Hiroi, T. [Department of Geological Sciences, Brown University, Providence, RI 02912 (United States); Birlan, M. [IMCCE, Observatoire de Paris, 77 Av. Denfert Rochereau, F-75014 Paris Cedex (France); Ricci, L. [California Institute of Technology, MC 249-17, Pasadena, CA, 91125 (United States)

    2014-08-20

    Although petrologic, chemical, and isotopic studies of ordinary chondrites and meteorites in general have largely helped establish a chronology of the earliest events of planetesimal formation and their evolution, there are several questions that cannot be resolved via laboratory measurements and/or experiments alone. Here, we propose the rationale for several new constraints on the formation and evolution of ordinary chondrite parent bodies (and, by extension, most planetesimals) from newly available spectral measurements and mineralogical analysis of main-belt S-type asteroids (83 objects) and unequilibrated ordinary chondrite meteorites (53 samples). Based on the latter, we suggest that spectral data may be used to distinguish whether an ordinary chondrite was formed near the surface or in the interior of its parent body. If these constraints are correct, the suggested implications include that: (1) large groups of compositionally similar asteroids are a natural outcome of planetesimal formation and, consequently, meteorites within a given class can originate from multiple parent bodies; (2) the surfaces of large (up to ∼200 km) S-type main-belt asteroids mostly expose the interiors of the primordial bodies, a likely consequence of impacts by small asteroids (D < 10 km) in the early solar system; (3) the duration of accretion of the H chondrite parent bodies was likely short (instantaneous or in less than ∼10{sup 5} yr, but certainly not as long as 1 Myr); (4) LL-like bodies formed closer to the Sun than H-like bodies, a possible consequence of the radial mixing and size sorting of chondrules in the protoplanetary disk prior to accretion.

  3. Noble Gases in the LEW 88663 L7 Chondrite

    Science.gov (United States)

    Miura, Y. N.; Sugiura, N.; Nagao, K.

    1995-09-01

    LEW88663 and some meteorites (e.g. Shaw) are the most highly metamorphosed meteorites among L group chondrites. Although the abundances of lithophile elements and oxygen isotopic compositions of the L7 chondrite LEW88663 (total recovered mass: 14.5g) are close to those of the range for L chondrites [1,2], metallic iron is absent and concentrations of siderophile elements are about half of typical values for L chondrites [3,4]. Petrographical and geochemical observation suggested that this meteorite has experienced partial melting [5]. As a part of our study on differentiated meteorites, we also investigated noble gases in this meteorite. We present here noble gas compositions of LEW88663 and discuss history of this meteorite. In addition, we will consider whether there is any evidence for bridging between chondrites and achondrites. Noble gases were extracted from a whole rock sample weighing 66.31 mg by total fusion, and all stable noble gas isotopes as well as cosmogenic radioactive 81Kr were analyzed using a mass spectrometer at ISEI, Okayama University. The results are summarized in the table. The concentrations of cosmogenic ^3He, ^21Ne, and ^38Ar are 7.3, 1.6 and 3.1x10^-8 cm^3STP/g, respectively. The cosmic-ray exposure ages based on them are calculated to be 4.7, 6.9 and 8.8 m.y., respectively, using the production rates proposed by [6, 7] and mean chemical compositions of L chondrites. The shorter cosmic-ray exposure ages T(sub)3 and T(sub)21 than T(sub)38 would be due to diffusive loss of lighter noble gases from the meteorite. The concentrations of trapped Kr and Xe in LEW88663 are lower than those for L6 chondrites [8], supporting thermal metamorphism for the meteorite higher than that for L6 chondrites. The Kr and Xe are isotopically close to those of the terrestrial atmospheric Kr and Xe, and elemental abundance ratios for Ar, Kr and Xe suggest adsorbed noble gas patterns of the terrestrial atmosphere. The terrestrial atmospheric Ar, Kr and Xe (most

  4. Thermomagnetic analysis of meteorites, 3. C3 and C4 chondrites

    Science.gov (United States)

    Herndon, J.M.; Rowe, M.W.; Larson, E.E.; Watson, D.E.

    1976-01-01

    Thermomagnetic analysis was made on samples of all known C3 and C4 chondrites in a controlled oxygen atmosphere. Considerable variation was noted in the occurrence of magnetic minerals, comparable to the variation observed earlier in the C2 chondrites. Magnetite was found as the only major magnetic phase in samples of only three C3 chondrites (2-4 wt.%) and the Karoonda C4 chondrite (7.7 wt.%). The magnetite content of these three C3 chondrites is only about one-third that observed in the C1 and C2 chondrites which were found to contain magnetite as the only magnetic phase. Five C3 chondrites were observed to undergo chemical change during heating, producing magnetite: this behavior is characteristic of troilite oxidation. Upper limits on initial magnetite content of about 1-9% were established for these meteorites. Samples of the remaining five C3 chondrites and the Coolidge C4 chondrite were found to contain both magnetite and metallic iron. In two samples, iron containing ???2% Ni was observed, while in the other four, the iron contained 6-8 wt.% Ni. In addition to containing both magnetite and iron metal, three of these samples reacted during heating to form additional magnetite. Variations in the magnetic mineralogy and, hence by inference bulk mineralogy, of C3 and C4 chondrites indicate a more complex genesis than is evident from whole-rock elemental abundance patterns. ?? 1976.

  5. Physical and Chemical Characterization of Carbonaceous Aerosols in Korea

    Science.gov (United States)

    Choung, S.; Jin, J. S.; Hwang, G. S.; Jang, K. S.; Han, W. S.; OH, J.; Kwon, Y.

    2014-12-01

    Atmospheric aerosols have been recently paid attention more in environmental research due to their negative effects on air quality, public health, and climate change. The aerosols contain approximately >20-50% carbonaceous components such as organic carbon (OC) and black carbon (BC) (or elemental carbon [EC]) derived from organic compounds, biomass burning, and incomplete combustion of fossil fuels. The physical, chemical, and biological properties of atmospheric aerosols are strongly dependent on the carbonaceous components. In particular, the BC could significantly affect the regional air quality in the northeastern Asia, because China is one of the foremost BC emission country in the world. Previous studies have mainly focused on the quantification and source identification for carbonaceous aerosols. However, understanding of physical and chemical properties for the carbonaceous aerosols related to environmental contamination and toxicity was still incomplete due to analytical difficulties. This study is addressed to evaluate the contribution of carbonaceous aerosols to air pollution through the surface, mass spectroscopic, and electron microscopic analyses, and determination of chemical composition and structure using the air particulate matter (PM2.5 and >PM2.5) samples.

  6. New Titanium Monosulfide Mineral Phase in Yamato 691 Enstatite Chondrite

    Science.gov (United States)

    Nakamura-Messenger, K; Clemett, S. J.; Rubin, A. E.; Choi, B.-G.; Zhang, S.; Rahman, Z.; Oikawa, K.; Keller, L. P.

    2011-01-01

    Yamato 691, an EH3 enstatite chondrite, was among the first meteorites discovered by chance in Antarctica by the Japanese Antarctic Research Expedition (JARE) team in 1969. This discovery led to follow-up searches for meteorites in Antarctica [1]. These international searches have been very successful recovering over 40,000 total specimens (and still counting), including martian and lunar meteorites. Titanium is partly chalcophile in enstatite-rich meteorites. Previous occurrences of Ti-bearing sulfides include troilite, daubrelite and ferroan alabandite in enstatite chondrites and aubrites [2], and heideite with 28.5 wt% Ti in the Bustee aubrite [3]. Here we report a new mineral from Yamato 691, ideally stoichiometric TiS, titanium monosulfide, a simple two-element mineral phase, yet with a very unique crystal structure that, to our knowledge, has not been observed previously in nature.

  7. The Tuxtuac, Mexico, meteorite, an LL5 chondrite fall

    Science.gov (United States)

    Graham, A. L.; Michel-Levy, M. Christophe; Danon, J.; Easton, A. J.

    1988-12-01

    The Tuxtuac meteorite fell in Zacatecas state, Mexico, on October 16, 1975, at 1820 hours. Two partly crusted masses, weighing 1924 g and 2340 g, were recovered. The stone is an ordinary chondrite, LL5, with olivine Fa30 and 19.22 wt pct total iron. The silicates contain numerous voids and a froth-like mesostasis is present within some chondrules. Metal phases present are kamacite (5.7-6.4 pct Ni, 6-7 pct Co) and high nickel metal (taenite 37-41 pct Ni, 1.7 + or - 0.3 pct Co; tetrataenite 47-52 pct Ni, 0.8-1.4 pct Co). The stone is unusual for an LL-group chondrite in that it exhibits neither large-scale brecciation features nor dark veins.

  8. Laboratory Studies Of Circumstellar Carbonaceous Grain Formation

    Science.gov (United States)

    Contreras, Cesar; Sciamma-O'Brien, Ella; Salama, Farid

    2014-06-01

    The study of the formation processes of dust is essential to understand the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar (IS) chemistry and in the formation of organic molecules, little is known on the formation processes of carbonaceous dust. We report the progress that was recently achieved in this domain using NASA Ames’ COSmIC facility (Contreras & Salama 2013, ApJS, 208, 6). PAHs are important chemical building blocks of IS dust. They are detected in IDPs and in meteoritic samples. Additionally, observational, laboratory, and theoretical studies have shown that PAHs are an important, ubiquitous component of the ISM. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, we have performed laboratory experiments to study the dynamic processes of carbon grain formation, starting from the smallest hydrocarbon molecules into the formation of larger PAH and further into nanograins. Studies of IS dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include the atoms O, N, and S, have recently been performed in our laboratory using the COSmIC facility to provide conditions that simulate IS and circumstellar environments. The species formed in the COSmiC chamber through a pulsed discharge nozzle plasma source are detected and characterized with a cavity ringdown spectrometer coupled to a time-of-flight mass spectrometer, thus providing both spectroscopic and ion mass information in-situ. Analysis of solid soot particles was also conducted using scanning electron microscopy at the UCSC/NASA Ames’ MACS facility. The SEM analysis of the deposition of soot from methane and acetylene precursors seeded in argon plasmas provide examples on the types of nanoparticles and micrograins that are produced in these gas mixtures under our experimental conditions. From these measurements, we derive information on

  9. The behavior of carbonaceous matter in Tagish Lake Meteorite at high P-T: implications for the survivability of organics during petrological processes and origin of life

    Science.gov (United States)

    Stagno, V.; DU, W.

    2015-12-01

    Recent models of planets formation have faced the possibility that (volatile-rich) carbonaceous chondrites are the possible carrier of water and complex carbon molecules. The Tagish Lake (TL) meteorite is a classified C2 ungroup chondrite whose bulk and organic chemistry compositions have received a considerable attention owing to the short-time exposure before being collected. TL is likely representative of D-type asteroids known to contain complex organic compounds, and was described including aliphatic and aromatic hydrocarbons considered to be building blocks of life (Gilmour 2001; Pizzarello et al. 2001). Recent studies on the spatial distribution and mineralogical association of organics in TL meteorites show a certain affinity of organic compounds for S-bearing phases such as Fe-Ni sulfide coexisting with abundant carbonate (Ca-Mg-Fe-Mn solid solution), magnetite and serpentine (Zega et al. 2010). In particular, carbonate is believed to form from the organic matter during hydrothermal alteration with implications for the carbon (C) isotopic signature. Therefore, the knowledge of how carbonaceous matter survived during the history of a meteorite at extreme pressures-temperatures is of fundamental importance to solve the mystery of the origin of life. In order to investigate the behavior of carbonaceous matter and to constrain the stability and structural evolution of organics and in Tagish Lake meteorite during petrological processes (melting, solid state reaction etc.), we carried heating experiments at 5 GPa and temperature between 800-1400 °C using multi anvil apparatus at GRC, Ehime University. The recovered samples were polished for textural and chemical characterization of the mineral phases using FE-SEM and electron microprobe, respectively. Ultra-thin sections, 80-100 nm thick, were prepared from the recovered samples using focused ion beam. These sections were then transferred to TEM grids for in situ X-ray absorption near-edge spectroscopy (XANES

  10. Carbonaceous solids as a model for adsorption by dispersion forces

    Energy Technology Data Exchange (ETDEWEB)

    Arnett, E.M.; Hutchinson, B.J.; Healy, M.H.

    1988-08-03

    Heats of adsorption of many liquids of widely varying structure are reported on several carbonaceous solids: graphite, anthracite coal, Ambersorb XE-348, and two graphitized carbon blacks, Carbopack B and F. Heats of adsorption on the two graphitized carbon black samples correlate closely with the polarizabilities of the adsorbate and the number of main group atoms in the molecules as might be expected for dispersion force interactions; there is no relationship to the basicities of the adsorbates. Except for the two graphitized carbon black samples, Carbopack B and F, correlation between the various type of carbonaceous solids is poor. 39 references, 6 figures, 3 tables.

  11. Conditioning of carbonaceous material prior to physical beneficiation

    Science.gov (United States)

    Warzinski, Robert P.; Ruether, John A.

    1987-01-01

    A carbonaceous material such as coal is conditioned by contact with a supercritical fluid prior to physical beneficiation. The solid feed material is contacted with an organic supercritical fluid such as cyclohexane or methanol at temperatures slightly above the critical temperature and pressures of 1 to 4 times the critical pressure. A minor solute fraction is extracted into critical phase and separated from the solid residuum. The residuum is then processed by physical separation such as by froth flotation or specific gravity separation to recover a substantial fraction thereof with reduced ash content. The solute in supercritical phase can be released by pressure reduction and recombined with the low-ash, carbonaceous material.

  12. Determining the relative extent of alteration in CM chondrites

    Science.gov (United States)

    Browning, Lauren B.; McSween, Harry Y., Jr.; Zolensky, Michael

    1993-03-01

    The aqueous alteration of CM chondrites provides a record of the processes attending the earliest stages of parent body evolution. However, resolving the alteration pathways of chondritic evolution requires a means for distinguishing the relative extent of alteration that individual samples have experienced. Three new indices for gauging the relative degree of alteration in CM chondrites based on modal and compositional analyses of 7 CM falls were proposed. The proposed alteration parameters are consistent with the basic tenets of several previous models and correlate with additional indices to produce an integrated method for determining the relative extent of alteration. The model predicts the following order of progressive alteration: Murchison (MC) is less than or equal to Bells (BL) is less than Murray (MY) is less than Cochabamba (CC) is less than Mighei (MI) is less than Nogoya (NG) is less than or equal to Cold Bokkeveld (CB). The broad range of CM phyllosilicate compositions observed within individual meteorites is fundamental to the characterization of the aqueous alteration process. Chemical analyses of CM phyllosilicates suggest that these phases became systematically enriched in Mg and depleted in Fe with increasing alteration.

  13. Timescales and settings for alteration of chondritic meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Krot, A N; Hutcheon, I D; Brearley, A J; Pravdivtseva, O V; Petaev, M I; Hohenberg, C M

    2005-11-16

    Most groups of chondritic meteorites experienced diverse styles of secondary alteration to various degrees that resulted in formation of hydrous and anhydrous minerals (e.g., phyllosilicates, magnetite, carbonates, ferrous olivine, hedenbergite, wollastonite, grossular, andradite, nepheline, sodalite, Fe,Ni-carbides, pentlandite, pyrrhotite, Ni-rich metal). Mineralogical, petrographic, and isotopic observations suggest that the alteration occurred in the presence of aqueous solutions under variable conditions (temperature, water/rock ratio, redox conditions, and fluid compositions) in an asteroidal setting, and, in many cases, was multistage. Although some alteration predated agglomeration of the final chondrite asteroidal bodies (i.e. was pre-accretionary), it seems highly unlikely that the alteration occurred in the solar nebula, nor in planetesimals of earlier generations. Short-lived isotope chronologies ({sup 26}Al-{sup 26}Mg, {sup 53}Mn-{sup 53}Cr, {sup 129}I-{sup 129}Xe) of the secondary minerals indicate that the alteration started within 1-2 Ma after formation of the Ca,Al-rich inclusions and lasted up to 15 Ma. These observations suggest that chondrite parent bodies must have accreted within the first 1-2 Ma after collapse of the protosolar molecular cloud and provide strong evidence for an early onset of aqueous activity on these bodies.

  14. Investigation of the chemical composition of mineral fractions of the Tsarev chondrite

    Energy Technology Data Exchange (ETDEWEB)

    Semenova, L.F.; Fisenko, A.V.; Kashkarova, V.G.; Melnikova, L.N.; Bezrogova, E.V.; Pomytkina, V.A.; Lavrukhina, A.K.

    1984-01-01

    A selective-dissolution method was used to study the chemical composition of mineral fractions of the Tsarev chondrite. Redistributions of Na, K, and P were found in mineral fractions of L-chondrites which have experienced different degrees of impact metamorphism. It is shown that the normative composition of inclusions in olivine in the Tsarev chondrite is characterized by a high content of diopside and anorthite components. 24 references.

  15. Origin of unusual impact melt rocks, Yamato-790964 and 790143 (LL-chondrites)

    OpenAIRE

    Yamaguchi,Akira/Scott,Edward R.D./Keil,Klaus

    1998-01-01

    We have studied Yamato (Y)-790964 and-790143,which are unusual paired impact-melted LL chondrites. Some petrologic aspects of these impact melt rocks are similar to those of the impact melted L-chondrite, Ramsdorf; these meteorites experienced nearly total melting, yet partly preserve chondritic textures. Olivine and chromite grains in Y-790964 and olivine in Y-790143 are the only relicts of the precursor materials; they were solid clasts during impact melting. All other portions (i.e., chond...

  16. Thermomagnetic analysis of meteorites. 3: C3 and C4 chondrites

    Science.gov (United States)

    Herndon, J. M.; Rowe, M. W.; Larson, E. E.; Watson, D. E.

    1974-01-01

    Thermomagnetic analysis on all of the C3 and C4 chondrites, conducted under conditions of controlled oxygen fugacity, indicates the presence of a thermally unstable component in at least 5 of the C3 chondrites which upon heating results in magnetite production. This unstable component is most likely troilite (FeS). The presence of the unstable substance may affect the estimation of paleointensities in meteorites which contain it. Our results indicate that Grosnaja, Ornans, Kainsaz, Felix, and Warrenton are likely to be less complicated for paleointensity determinations than the other C3 chondrites. Both C4 chondrites should lead to reliable results.

  17. Changes in the vertical temperature structure associated with carbonaceous aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Penner, J E; Chuang, C C; Santer, B D; Taylor, K

    2002-02-08

    Carbonaceous aerosols from anthropogenic activities act to both scatter and absorb solar radiation. It has been postulated that absorption by aerosols might significantly alter both the vertical temperature structure of the atmosphere and cloud fraction [Hansen et al. 1997, Ackerman et al, 2000]. Since both effects may alter the assessment of climate change associated with human activities, it is very important to understand both the magnitude and the mechanism by which carbonaceous aerosols affect climate. In this paper, we used a coupled climate and chemistry transport model to estimate the effects of carbonaceous aerosols on the vertical temperature structure and their effects on cloud fraction. A series Of control simulations were also carried out to compare the results of the model in which carbonaceous aerosols interact with climate with those in which they do not. We will present the temperature difference between simulations that include the effect of black carbon on the radiation field and those that do not, both at the surface and in the free troposphere. We will also discuss the change of temperature lapse rate and changes of cloud fraction associated with black carbon.

  18. [Investigation of Carbonaceous Airborne Particles by Scanning Proton Microprobe].

    Science.gov (United States)

    Bao, Liang-man; Liu, Jiang-feng; Lei, Qian-tao; Li, Xiao-lin; Zhang, Gui-lin; Li, Yan

    2016-01-15

    Carbonaceous particles are an important component of the atmospheric aerosol particles and important for global climate change, air quality and human health. The PM₁₀ single particles from two environmental monitor locations and seven pollution emission sources were analyzed using scanning proton microprobe (SPM) techniques. The concentration of carbon in individual particles was quantitatively determined by proton non-Rutherford elastic backscattering spectrometry (EBS). The results of this investigation showed that carbonaceous particles were dominant in the pollution sources of coal and oil combustions, diesel busexhaust and automobile exhaust, while inorganic particles were dominant in the sources of steel industry, cement dust and soil dust. Carbonaceous matter was enriched in particles from the city center, while mineral matter was the main component of airborne particles in the industrial area. Elemental mapping of single aerosol particles yielded important information on the chemical reactions of aerosol particles. The micro-PIXE (particle induced X-ray emission) maps of S, Ca and Fe of individual carbonaceous particles showed that sulfuration reaction occurred between SO₂and mineral particles, which increased the sulfur content of particles. PMID:27078933

  19. Petrofabric of Zag and Pułtusk Meteorites: Implications for Impact Conditions on the H Chondrite Parent Body

    Science.gov (United States)

    Krzesińska, A.; Gattacceca, J.; Friedrich, J. M.; Rochette, P.

    2014-09-01

    Petrofabric of H chondrites is characterized by combining tomographic reconstruction of metal grains, anisotropy of magnetic susceptibility and petrographic observations. The chondrites possess foliation but also well defined lineation.

  20. Group IIE Iron Meteorites; Metal Composition, Formation, Relationship to Ordinary Chondrites

    Science.gov (United States)

    Wasson, J. T.; Scott, E. R. D.

    2011-03-01

    INAA data for metal in 8 new and 12 known IIE irons show they crystallized from various silicate-rich Fe-Ni melts with diverse S contents after impacts melted an ordinary chondrite asteroid that was probably more reduced than H chondrites.

  1. Chemical and physical studies of type 3 chondrites. VII - Annealing studies of the Dhajala H3.8 chondrite and the thermal history of chondrules and chondrites

    Science.gov (United States)

    Keck, B. D.; Guimon, R. K.; Sears, D. W. G.

    1986-01-01

    Samples of the Dhajala meteorite were annealed at 600-1000 C for 1, 2, 10, 20 and 100 h and their thermoluminescence (TL) properties were measured. After annealing at less than 900 deg, the TL sensitivity decreased by a factor of two; at higher temperatures, it fell by an order of magnitude. Data indicate that the annealing treatment caused the low-temperature feldspar in Dhajala to be converted to feldspar of a high-temperature (disordered) form. Low-temperature feldspar was found in the meteorite's TL-sensitive chondrules which comprised about 20 percent of those separated. It is suggested that these chondrules suffered greater crystallization of their mesostasis than the other chondrules, and equilibrated to lower temperatures. Based on TL data, there appears to be no relationship between post-metamorphic cooling rate and petrologic type for the 3.5-3.9 chondrites.

  2. Petrology and In Situ Trace Element Chemistry of a Suite of R Chondrites

    Science.gov (United States)

    Mittlefehldt, D. W.; Peng, Z. X.; Torrano, Z. A.

    2015-01-01

    Rumuruti (R) chondrites are characterized by low chondrule/matrix modal ratios, high oxidation state, small mean chondrule size, abundant sulfides and low metal contents, and are of petrologic types 3 to 6 [1, 2]. LAP 04840 (R5, [3]) and MIL 11207 (R6), contain the high-T hydrous phases amphibole and mica [3, 4]; not all equilibrated R chondrites contain these [2]. R chondrites thus can provide evidence on whether there are compositional effects caused by high-T, high-fluid metamorphism of nebular materials. We are investigating a suite of R chondrites of diverse petrologic grades to further understand the nature of the metamorphic processes that engendered them [5]. We report on our petrological studies, plus preliminary in situ analyses of trace elements in amphibole-bearing R chondrites.

  3. Immobilization of pentachlorophenol in soil using carbonaceous material amendments

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bei [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China)], E-mail: bwen@rcees.ac.cn; Li Ruijuan; Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China); Shan Xiaoquan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China)], E-mail: xiaoquan@rcees.ac.cn; Fang Jing; Xiao Ke [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China); Khan, Shahamat U. [Department of Chemistry and Biochemistry, MSN 3E2, George Mason University, 4400 University Drive, Fairfax, VA 22030-4444 (United States)

    2009-03-15

    In this study, three pentachlorophenol (PCP) laboratory-spiked and one field-contaminated soil were amended with 2.0% char, humic acid (HA) and peat, respectively. The amended soils were aged for either 7 or 250 days. After amendment, CaCl{sub 2} extractability of PCP was significantly decreased. Desorption kinetics indicated that the proposed amendment could lead to a strong binding and slow desorption of PCP in soils. Amendment with char reduced the bioaccumulation factor (BAF) of PCP most significantly for earthworms (Eisenia fetida) in all soils studied. The results of both physicochemical and biological tests suggested that amendment reduced PCP bioavailability quickly and enduringly, implying that carbonaceous material amendment, especially char amendment, was a potentially attractive in situ remediation method for sequestration of PCP in contaminated soil. - Carbonaceous material amendment was a potential in situ remediation method for pentachlorophenol contaminated soil.

  4. Study of the supermolecular structure of carbonaceous materials

    International Nuclear Information System (INIS)

    A method is proposed for calculating the form of structural pores and distortions of ordered crystalline regions in carbonaceous materials using X-ray parameters. The region of supermolecular structural order (SMO) of carbonaceous materials on thermal treatment and on neutron irradiation has been investigated. It has been established that the graphitization process is preceded by a qualitative change on the SMO of the initial materials. It has been shown that as the result of the neutron irradiation of graphite, with a rise in the temperature of irradiation the distortions in the crystalline regions grow, leading to irreversible processes of breakdown of the latter, to a redistribution and reorientation of the structural porosity, and to a change in the shape of the pores. 16 refs

  5. Immobilization of pentachlorophenol in soil using carbonaceous material amendments

    International Nuclear Information System (INIS)

    In this study, three pentachlorophenol (PCP) laboratory-spiked and one field-contaminated soil were amended with 2.0% char, humic acid (HA) and peat, respectively. The amended soils were aged for either 7 or 250 days. After amendment, CaCl2 extractability of PCP was significantly decreased. Desorption kinetics indicated that the proposed amendment could lead to a strong binding and slow desorption of PCP in soils. Amendment with char reduced the bioaccumulation factor (BAF) of PCP most significantly for earthworms (Eisenia fetida) in all soils studied. The results of both physicochemical and biological tests suggested that amendment reduced PCP bioavailability quickly and enduringly, implying that carbonaceous material amendment, especially char amendment, was a potentially attractive in situ remediation method for sequestration of PCP in contaminated soil. - Carbonaceous material amendment was a potential in situ remediation method for pentachlorophenol contaminated soil

  6. Active coke: Carbonaceous materials as catalysts for alkane dehydrogenation

    OpenAIRE

    McGregor, J.; Huang, Z; Parrott, E.; Zeitler, J.; Nguyen, K.; Rawson, J.; Carley, A; Hansen, T.; Tessonnier, J.; Su, D.; Teschner, D; Vass, E.; Knop-Gericke, A.; Schlögl, R.; Gladden, L.

    2010-01-01

    The catalytic dehydrogenation (DH) and oxidative dehydrogenation (ODH) of light alkanes are of significant industrial importance. In this work both carbonaceous materials deposited on VOx/Al2O3 catalysts during reaction and unsupported carbon nanofibres (CNFs) are shown to be active for the dehydrogenation of butane in the absence of gas-phase oxygen. Their activity in these reactions is shown to be dependent upon their structure, with different reaction temperatures yielding structurally dif...

  7. Uranium band types in carbonaceous sediments with different diagenesis levels

    International Nuclear Information System (INIS)

    Uraniferous peats, lignites and coals were studied by chemical and geological methods in order to determine the influence of carbonaceous substances with different diagenesis levels on uranium enrichment in sediments. It was found that the main factor of deposit genesis is not the chemical bending of uranium to the organic substance but rather the reduction from mobile U(VI) to immobile U(IV) in the course of diagenesis to epigenesis. (orig./PW)

  8. Analyses and Characterization of Fossil Carbonaceous Materials for Silicon Production

    OpenAIRE

    Myrvågnes, Viktor

    2008-01-01

    Production of high silicon alloys is carried out in submerged arc furnaces by reduction of silicon bearing oxides (typically quartz) with carbon materials. Carbonaceous materials like coal, coke, charcoal and woodchips are commonly used as reduction materials in the process. Primarily based on historical prices of charcoal compared to fossil reduction materials, the Norwegian Ferroalloy Industry has mostly been using coal and coke (char) as the source of carbon. From a process point of view, ...

  9. Biomass-derived carbonaceous materials as components in wood briquettes

    Energy Technology Data Exchange (ETDEWEB)

    Stengl, S.; Koch, C.; Stadlbauer, E.A.; Scheer, J. [Univ. of Applied Sciences, THM Campus Giessen, Giessen (Germany); Weber, B. [Instituto de Ingenieria de la Universidad Nacional Autonoma de Mexico (UNAM), Coyoacan (Mexico); Strohal, U.; Fey, J. [Strohal Anlagenbau, Staufenberg (Germany)

    2012-11-01

    The present paper describes a briquette composed of a substantial amount of wooden biomass and up to 35% of carbonaceous materials derived from biogenic residues. The cellulosic component may be a mixture of any wooden residue. Suitable substrates for the carbonaceous fraction are vegetation wastes from land management or agriculture. Depending on physical and chemical nature of the substrate, Hydrothermal Carbonisation (HTC) or Low Temperature Conversion (LTC) may be used to produce the carbonaceous part of the briquette. HTC turns wet biomass at temperatures around 200 deg C in an autoclave into lignite whereas LTC treatment at 400 deg C and atmospheric pressure produces black coal. This is manifested by a molar ratio of 0.1 {<=} H/C (LTC) {<=} 0.7; 0.05{<=} O/C (LTC) {<=} 0.4 and 0.7 < H/C (HTC) <1.5 ; 0.2< O/C (HTC) < 0.5. Solid state {sup 13}C-NMR confirms these findings showing a strong absorption band for sp{sup 2}-hybridized carbon atoms at chemical shifts of 100 ppm und 165 ppm for LTC biochar. Depending on the substrate, HTC gives rise to an increase in the specific calorific value (MJ/kg) by a factor of {Psi} {approx} 1.2 - 1.4; LTC by 1.5 - 1.8. In addition ash melting points are significantly increased; in case of wheat straw by about 200 deg C. Compacted products may have a cylindrical or rectangular profile.

  10. Kirishites—high-carbonaceous hairlike fibers associated with volkhovites

    Science.gov (United States)

    Skublov, G. T.; Marin, Yu. B.; Skublov, S. G.; Vasil'Ev, E. V.; Gembitskaya, I. M.; Nechaeva, E. S.; Tarasenko, Yu. N.

    2009-12-01

    Kirishites are highly carbonaceous hairlike fibers 30-100 μm in thickness and 3-30 mm long, which jut out as bunches on the surface of cinder and shungite fragments associated with volkhovites (Holocene tectitelike glasses corresponding to the rocks of kimberlite-lamproite-carbonatite series in composition). Kirishite fibers are zonal. Their inner (axial) zone is composed of high-nitrogen proteinlike compounds, whereas the outer zone is essentially carbonaceous, with a high content of organoelemental complexes (Si, Fe) and numerous micrometer-sized anomalies of major, volatile, trace, and ore elements. Longitudinal zoning is established in aposhungite kirishites: the consecutive change of maximum concentrations—K, Na, Cl, C, Mn → C, S, V, Ni, Cu, Zn → S, N, Ba, Te, Pb, Bi, Nd—is traced from the roots of fibers to their ends. It is suggested that as volkhovites were forming, fragments of cinder and shungite underwent partial melting. The highly carbonaceous compounds released due decompression and explosion were squeezed out from fragments and solidified as fibers during fall of fragments on the Earth’s surface.

  11. Indigenous Carbonaceous Matter in the Nakhla Mars Meteorite

    Science.gov (United States)

    Clemett, S. J.; Thomas-Keprta, K. L.; Rahman, Z.; Le, L.; Wentworth, S. J.; Gibson, E. K.; McKay, D. S.

    2016-01-01

    Detailed microanalysis of the Martian meteorite Nakhla has shown there are morphologically distinct carbonaceous features spatially associated with low-T aqueous alteration phases including salts and id-dingsite. A comprehensive suite of analytical instrumentation including optical microscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, focused ion beam (FIB) microscopy, transmission electron microscopy (TEM), two-step laser mass spectrometry (mu-L(sup 2)MS), laser mu-Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nanoscale secondary ion mass spectrometry (NanoSIMS) are being used to characterize the carbonaceous matter and host mineralogy. The search for carbonaceous matter on Mars has proved challenging. Viking Landers failed to unambiguously detect simple organics at either of the two landing sites although the Martian surface is estimated to have acquired at least 10(exp15) kg of C as a consequence of meteoritic accretion over the last several Ga. The dearth of organics at the Martian surface has been attributed to various oxidative processes including UV photolysis and peroxide activity. Consequently, investigations of Martian organics need to be focused on the sub-surface regolith where such surface processes are either severely attenuated or absent. Fortuitously since Martian meteorites are derived from buried regolith materials they provide a unique opportunity to study Martian organic geochemistry.

  12. Gallium and germanium in the metal and silicates of L- and LL-chondrites.

    Science.gov (United States)

    Chou, C.-L.; Cohen, A. J.

    1973-01-01

    Concentrations of Ga and Ge in the metal of 31 L-, 8 LL- and 2 H-chondrites, and in the silicates of 12 L- and LL-chondrites have been determined by spectrophotometric methods. The ranges of Ga contents in the metal of L- and LL-chondrites are 1.1 to 36.9 ppm and 1.0 to 34.1 ppm, respectively. The Ge content in the metal is positively correlated with Ga and ranges from 89.1 to 160 ppm and from 126 to 308 ppm for L- and LL-chondrites, respectively. The Ga content in the silicates of L-chondrites varies from 4.0 to 8.9 ppm. The Ga and Ge contents in the metal are clearly lower in unequilibrated than in equilibrated L- and LL-group chondrites. Unequilibrated and equilibrated chondrites are well separated in the plots of Ga vs Ge in the metal, and the L- and LL-groups are also well resolved. The Ga and Ge in the metal are well correlated with petrologic grade. This suggests that Ga and Ge variations in the metal are related to thermal metamorphism. There is evidence of an enrichment of Ga in the metal due to shock reheating.

  13. Chondritic Models of 4 Vesta: Comparison of Data from the Dawn Mission with Predicted Internal Structure and Surface Composition/Mineralogy

    Science.gov (United States)

    Toplis, M. J.; Mizzon, H.; Forni, O.; Monnereau, M.; Barrat, J-A.; Prettyman, T. H.; McSween, H. Y.; McCoy, T. J.; Mittlefehldt, D. W.; De Sanctis, M. C.; Raymond, C. A.; Russell, C. T.

    2012-01-01

    While the HEDs provide an extremely useful basis for interpreting data from the Dawn mission, there is no guarantee that they provide a complete vision of all possible crustal (and possibly mantle) lithologies that are exposed at the surface of Vesta. With this in mind, an alternative approach is to identify plausible bulk compositions and use mass-balance and geochemical modelling to predict possible internal structures and crust/mantle compositions and mineralogies. While such models must be consistent with known HED samples, this approach has the potential to extend predictions to thermodynamically plausible rock types that are not necessarily present in the HED collection. Nine chondritic bulk compositions are considered (CI, CV, CO, CM, H, L, LL, EH, EL). For each, relative proportions and densities of the core, mantle, and crust are quantified. This calculation is complicated by the fact that iron may occur in metallic form (in the core) and/or in oxidized form (in the mantle and crust). However, considering that the basaltic crust has the composition of Juvinas and assuming that this crust is in thermodynamic equilibrium with the residual mantle, it is possible to calculate a single solution to this problem for a given bulk composition. Of the nine bulk compositions tested, solutions corresponding to CI and LL groups predicted a negative metal fraction and were not considered further. Solutions for enstatite chondrites imply significant oxidation relative to the starting materials and these solutions too are considered unlikely. For the remaining bulk compositions, the relative proportion of crust to bulk silicate is typically in the range 15 to 20% corresponding to crustal thicknesses of 15 to 20 km for a porosity-free Vesta-sized body. The mantle is predicted to be largely dominated by olivine (greater than 85%) for carbonaceous chondrites, but to be a roughly equal mixture of olivine and pyroxene for ordinary chondrite precursors. All bulk compositions

  14. Airborne contamination of forest soils by carbonaceous particles from industrial coal processing

    OpenAIRE

    Schmidt, M. W. I.; Knicker, Heike; Hatcher, Patrick G.; Kögel-Knabner, I.

    2000-01-01

    In the German Ruhr-area industrial coal processing emitted large amounts of carbonaceous particles for a century until 1970. Our objectives were to detect the presence of airborne carbonaceous particles and assess their impact on the chemical structure of soil organic matter in two forest soils (Podzols) with potential sources of carbonaceous particles approximately 10 to 30 km away. Contamination was not visible macroscopicaily. Organic matter was characterized in bulk soils and in particle-...

  15. Pb-Pb dating of individual chondrules from the CBa chondrite Gujba

    DEFF Research Database (Denmark)

    Bollard, Jean Francois André; Connelly, James; Bizzarro, Martin

    2015-01-01

    The CB chondrites are metal-rich meteorites with characteristics that sharply distinguish them from other chondrite groups. Their unusual chemical and petrologic features and a young formation age of bulk chondrules dated from the CBa chondrite Gujba are interpreted to reflect a single...... well-behaved Pb-Pb systematics of all four chondrules, a precise formation age and the concordancy of the Mn-Cr, Hf-W, and I-Xe short-lived radionuclide relative chronometers, we propose that Gujba may serve as a suitable time anchor for these systems....

  16. STARDUST INVESTIGATION INTO THE CR CHONDRITE GROVE MOUNTAIN 021710

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xuchao; Lin Yangting [Key Laboratory of the Earth' s Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, 19 Beituchengxi Road, Beijing 100029 (China); Floss, Christine [Laboratory for Space Sciences and Physics Department, Washington University, One Brookings Drive, St. Louis, MO 63130 (United States); Bose, Maitrayee, E-mail: linyt@mail.igcas.ac.cn [Department of Chemistry and Biochemistry, Arizona State University, P.O. Box 871604, Tempe, AZ 85287 (United States)

    2013-05-20

    We report the presolar grain inventory of the CR chondrite Grove Mountain 021710. A total of 35 C-anomalous grains ({approx}236 ppm) and 112 O-anomalous grains ({approx}189 ppm) were identified in situ using NanoSIMS ion imaging. Of 35 C-anomalous grains, 28 were determined to be SiC grains by Auger spectroscopy. Seven of the SiC grains were subsequently measured for N and Si isotopes, allowing classification as one nova grain, one Y grain, one Z grain, and four mainstream grains. Eighty-nine out of 112 O-anomalous grains belong to Group 1, indicating origins in low-to-intermediate-mass red giant and asymptotic giant branch stars. Twenty-one are Group 4 grains and have origins in supernovae. Auger spectroscopic elemental measurements of 35 O-anomalous grains show that 33 of them are ferromagnesian silicates. They have higher Mg/(Mg+Fe) ratios than those reported in other meteorites, suggesting a lower degree of alteration in the nebula and/or asteroid parent bodies. Only two oxide grains were identified, with stoichiometric compositions of MgAl{sub 2}O{sub 4} and SiO{sub 2}, respectively. The presolar silicate/oxide ratio of GRV 021710 is comparable with those of the CR3 chondrites (QUE 99177 and MET 00426) and primitive interplanetary dust particles. In order to search for presolar sulfides, the meteorite was also mapped for S isotopes. However, no presolar sulfides were found, suggesting a maximum abundance of 2 ppm. The scarcity of presolar sulfides may be due to their much faster sputtering rate by cosmic rays compared to silicates.

  17. The 'Porky' Inclusion from the Axtell Carbonaceous Chondrite: A Hercynite-bearing Condensate with Large 48Ca and 50Ti Excesses

    Science.gov (United States)

    Caillet, C.; Zinner, E.

    1995-09-01

    Only a few hercynite-rich refractory inclusions have been identified to date [1,2]. Porky (450 micrometers long) is an unusual CAI with texturally distinct regions and dominant intergrown oxide mineral phases [3]. The core is a symplectitic vermicular intergrowth of ubiquitous ferroan spinel and ilmenite. Inwards branching of ilmenite crystals and projecting fan-shaped hibonite from the borders suggest crystallization from a fast cooling melt. Three marginal regions are mineralogically identical to the core: two fine-grained areas with acicular corroded crystals contrast with an altered spinel area. The inclusion is entirely rimmed by yellow luminescing Al-diopside. Hibonite exhibits pale orange luminescence. Broad beam analyses reveal high FeO (22.5 wt %) and low CaO/Al2O3 (0.024) for the whole CAI [3]. Si, Al and Ti concentrations are very similar to those of CM inclusions. There are no significant chemical differences between the coarse-grained core and the fine-grained regions. Hibonite shows widely varying concentrations (in wt %) of TiO2 (1.5-6.8), MgO (1.2-3.6) and FeO (0.7-4.7). Spinel contains much FeO (20.5-27). Hercynite close to the border of the inclusion next to hibonite has high MgO (11 wt%) and small amounts of Cr2O3 (0.15-1.55) and V2O3 (0.1-0.3), implying a melt origin. The Al-rich, Si-poor composition indicates that Porky experienced higher temperatures than CV3 inclusions. The presence of Fe-rich mineral phases, the lack of metal grains, the relatively high NiO concentration (average = 0.25), and the orange luminescence of hibonite indicate formation or re-equilibration in an oxidizing environment. Trace element patterns are basically volatility-fractionated and mostly ultrarefractory-depleted but vary from a Group II pattern in hercynite (to a lesser extent in hibonite and diopside) to extreme excesses of the less refractory elements Nb, Eu, Tm and Yb in a fine-grained region (Fig. 1). These patterns indicate condensation from a UR-depleted gas at varying temperatures (highest for the core, lowest for the fine-grained regions) and under varying redox conditions and trace element compositions. The refractory trace elements measured in hercynite are likely to reside in ilmenite (the abundances in this phase would then be ~15 times higher than shown in Fig. 1 for hercynite). In contrast to large 48Ca and 50Ti depletions in hibonite-hercynite inclusion Lanc HH-1 [2], Porky shows extreme excesses in 48Ca (37.3+/-5.9 (2s) per mil in hibonite and 27.4+/-4.8 per mil in diopside) and 50Ti (~62 per mil in hibonite and ilmenite). No clear 26Mg excess and no Mg and Fe isotopic mass fractionation were detected. Fe isotopic ratios in hercynite are normal; the Allende inclusion EK1-4-1 thus remains the only object in which a large 58Fe excess is associated with 48Ca and 50Ti excesses [4]. References: [1] Brigham C. A. et al. (1986) LPSC XVII, 85-86. [2] Fahey A. J. et al. (1994) GCA, 58, 4779-4793. [3] Caillet C. (1994) Meteoritics, 29, 453-454. [4] V"lkening J. and Papanastassiou D. A. (1989) Astrophys. J., 347, L43-L46.

  18. Stable Chlorine Isotopes and Elemental Chlorine by Thermal Ionization Mass Spectrometry and Ion Chromatography; Martian Meteorites, Carbonaceous Chondrites and Standard Rocks

    Science.gov (United States)

    Nakamura, N.; Nyquist, L. E.; Reese, Y.; Shih, C.-Y.; Fujitani, T.; Okano, O.

    2011-01-01

    Recently significantly large mass fractionation of stable chlorine isotopes has been reported for terrestrial and lunar samples [1,2]. In addition, in view of possible early solar system processes [3] and also potential perchlorate-related fluid/microbial activities on the Martian surface [4,5], a large chlorine isotopic fractionation might be expected for some types of planetary materials. Due to analytical difficulties of isotopic and elemental analyses, however, current chlorine analyses for planetary materials are controversial among different laboratories, particularly between IRMS (gas source mass spectrometry) and TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1,6,7] for isotopic analyses, as well as between those doing pyrohydrolysis and other groups [i.e. 6,8]. Additional careful investigations of Cl isotope and elemental abundances are required to confirm real chlorine isotope and elemental variations for planetary materials. We have developed a TIMS technique combined with HF-leaching/ion chromatography at NASA JSC that is applicable to analysis of small amounts of meteoritic and planetary materials. We present here results for several standard rocks and meteorites, including Martian meteorites.

  19. Thermal and Impact History of the H Chondrite Parent Asteroid during Metamorphism: Constraints from Metallic Fe-Ni

    CERN Document Server

    Scott, Edward R D; Goldstein, Joseph I; Wakita, Shigeru

    2014-01-01

    We have studied cloudy taenite, metallographic cooling rates, and shock effects in 30 H3-6 chondrites to elucidate the thermal and early impact history of the H chondrite parent body. We focused on H chondrites with Ar-Ar ages greater than 4.4 Gyr and unshocked and mildly shocked H chondrites, as strongly shocked chondrites with such old ages are very rare. Cooling rates for most H chondrites at 500 C are 10-50 C/Myr and do not decrease systematically with increasing petrologic type as predicted by the onion-shell model in which types 3 to 5 are arranged in concentric layers around a type 6 core. Some type 4 chondrites cooled slower than some type 6 chondrites and type 3 chondrites did not cool faster than other types, contrary to the onion-shell model. Cloudy taenite particle sizes, which range from 40 to 120 nm, are inversely correlated with metallographic cooling rates and show that the latter were not compromised by shock heating. The three H4 chondrites that were used to develop the onion-shell model, St...

  20. Rare Earth Element Systematics in 48 R Chondrite Ca,Al-Rich Inclusions

    Science.gov (United States)

    Horstmann, M.; Krause, J.; Berndt, J.; Bischoff, A.

    2012-09-01

    The compiled rare earth element systematics of 48 (including 32 new) Ca,Al-rich inclusions from seven R chondrites will be presented and implications for their formation and evolution will be discussed.

  1. Thermoluminescence Sensitivity and Thermal History of Unequilibrated Ordinary Chondrites: Review and Update

    Science.gov (United States)

    Benoit, P. H.; Ninagawa, K.; Sears, D. W. G.

    2000-01-01

    We report on the induced thermoluminescence (TL) data for 102 unequilibrated ordinary chondrites. We discuss these data in terms of pairing, weathering, and parent body thermal history. We identify ten possible meteorites of petrologic types 3.0-3.1.

  2. Correlated modal mineralogy, aqueous alteration and oxygen isotope composition of CM Chondrites

    OpenAIRE

    Howard, K. T.; Benedix, G. K.; Bland, P. A.; Greenwood, R. C.; I. Franchi; Cressy, G.

    2010-01-01

    In this study we move beyond defining alteration sequences in CM chondrites towards understanding the relationship between modal mineralogy, the extent of aqueous alteration and O-isotope compositions.

  3. Chelyabinsk LL5 chondrite - insight into shock effects on S-type asteroids

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Gritsevich, M.; Grokhovsky, V. I.; Yakovlev, G. A.; Haloda, J.; Halodová, P.; Michallik, R. M.; Penttilä, A.; Muinonen, K.

    2015. [Bridging the Gap /3./. 21.09.2015-23.09.2015, Freiburg] Institutional support: RVO:67985831 Keywords : astrophysics * asteroids * chondrite Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.hou.usra.edu/meetings/gap2015/pdf/1022.pdf

  4. Northwest Africa 8709: A Rare but Revealing Type 3 Ordinary Chondrite Melt Breccia

    Science.gov (United States)

    Ruzicka, A. M.; Hutson, M.; Friedrich, J. M.; Bland, P. A.; Pugh, R.

    2015-07-01

    We discuss the discovery of a rare L3 melt breccia, which has implications for compaction processes that must have contributed to the lithification of what are expected to have been initially porous primordial chondritic agglomerates.

  5. X-Ray Micro-Computed Tomography Imaging of the Buzzard Coulee Chondrite

    Science.gov (United States)

    Melanson, D.; Samson, C.; Herd, R. K.; Fry, C.; McCausland, P. J. A.; Umoh, J.; Holdsworth, D. W.

    2012-03-01

    This abstract outlines research and some results of X-ray micro-computed tomography imaging of the Buzzard Coulee H4 chondrite. A comparison of bulk density results and an analysis of radio-density profile curves are discussed.

  6. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Directory of Open Access Journals (Sweden)

    J.-J. Cao

    2013-01-01

    Full Text Available An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles from Pudong (China was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment experiment in 2009. Data for organic and elemental carbon (OC and EC, organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs, and stable carbon isotopes OC (δ13COC and EC (δ13CEC were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA; high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = −24.5 ± 0.8‰ and δ13CEC = −25.1 ± 0.6‰ indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter, with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  7. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Directory of Open Access Journals (Sweden)

    J.-J. Cao

    2012-07-01

    Full Text Available An intensive investigation of carbonaceous PM2.5 and TSP from Pudong (China was conducted as part of the MIRAGE-Shanghai Experiment in 2009. Data for organic and elemental carbon (OC and EC, organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs, and stable C isotopes OC (δ13COC and EC (δ13CEC were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA; high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = −24.5 ± 0.8‰ and δ13CEC = −25.1 ± 0.6‰ indicated that fossil fuels were the most important source for carbonaceous PM2.5, with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%: other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  8. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, M.A. (Brookhaven National Lab., Upton, NY (United States)); Cofer, W.R. III; Levine, J.S. (National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center)

    1990-10-01

    The identity and ambient mass concentrations of radiatively important carbonaceous aerosols were measured for a boreal forest prescribed burn conducted in northern Ontario, CAN in August 1989. Nonsize-segregated airborne particles were collected for smoldering-fire and full-fire conditions using a helicopter sampling platform. Total carbon (TC), organic carbon (OC) and elemental carbon (EC) were measured. Smoke plume mass concentrations of the OC and EC particles were greatest for full-fire conditions and had ranges of 1.560 to 2.160 mg/m{sup {minus}1} (OC) and 0.120 to 0.160 mg/m{sup {minus}3} (EC) with OC:EC ratios of 10 to 18, respectively. Smoldering fire conditions showed smoke plume OC and EC levels of 0.570--1.030 mg/m{sup {minus}3} (OC) and 0.006--0.050 mg/m{sup {minus}3} (EC) and much higher ratios of OC:EC (21 to 95). These aerosol data indicate the formation of EC particles is greatest during full-fire combustion of boreal forest material relative to smoldering combustion. However, EC particles comprise a minor fraction of the particulate carbon smoke aerosols for both full-fire and smoldering conditions; the major component of carbonaceous smoke aerosols emitted during the prescribed burn is OC. Overall, the OC and EC in-plume smoke aerosol data show nonuniform production of these particles during various stages of the prescribed burn, and major differences in the type of carbonaceous aerosol that is generated (OC versus EC).

  9. Source apportionment of carbonaceous aerosol in southern Sweden

    Directory of Open Access Journals (Sweden)

    J. Genberg

    2011-05-01

    Full Text Available A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (82 %, which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (38 % and fossil fuel combustion (33 % were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 8.2 compared to the measurements.

  10. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  11. Screening of carbonaceous nanoporous materials for capture of nerve agents.

    Science.gov (United States)

    Kowalczyk, Piotr; Gauden, Piotr A; Terzyk, Artur P; Neimark, Alexander V

    2013-01-01

    A strategy for combined experimental and computational screening of candidate carbonaceous materials for capturing highly volatile nerve agents at ambient temperature using physisorption. Based on theoretical calculations of Henry constants and zero-coverage adsorption enthalpies for sarin and DMMP (its common stimulant) adsorbed in model slit-shaped carbon pores at 298 K, we found the following. Slit-shaped carbon pores with pore width ~0.5 nm are optimal for agent adsorption due to strong confinement of adsorbed molecules. Agent adsorption enthalpy at zero coverage computed for optimal pore width is very high and reaches ~83 kJ mol(-1). Widening of pore width above ~1 nm results in a significant decrease of the Henry constant and zero-coverage adsorption enthalpy (~44 kJ mol(-1)). Polydispersity of studied candidate carbonaceous materials strongly affects adsorption capacity for DMMP under the operating conditions. The optimal carbonaceous adsorbent, pitch-based P7 activated carbon fiber, adsorbed ~100 μg g(-1) DMMP at 0.03 μg m(-3). Commercial Norit activated carbon adsorbed only ~20 μg g(-1) DMMP at 0.03 μg m(-3). Surprisingly, a small shift of the pore size distribution towards wider micropores has a great impact on agent adsorption. Because the adsorption enthalpies computed at zero coverage weakly dependent on pore size, the heat released during agent adsorption is similar for all studied candidate adsorbents (i.e.~55-60 kJ mol(-1)). PMID:23165364

  12. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Science.gov (United States)

    Cao, J.-J.; Zhu, C.-S.; Tie, X.-X.; Geng, F.-H.; Xu, H.-M.; Ho, S. S. H.; Wang, G.-H.; Han, Y.-M.; Ho, K.-F.

    2013-01-01

    An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = -24.5 ± 0.8‰ and δ13CEC = -25.1 ± 0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter), with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  13. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    International Nuclear Information System (INIS)

    The identity and ambient mass concentrations of radiatively important carbonaceous aerosols were measured for a boreal forest prescribed burn conducted in northern Ontario, CAN in August 1989. Nonsize-segregated airborne particles were collected for smoldering-fire and full-fire conditions using a helicopter sampling platform. Total carbon (TC), organic carbon (OC) and elemental carbon (EC) were measured. Smoke plume mass concentrations of the OC and EC particles were greatest for full-fire conditions and had ranges of 1.560 to 2.160 mg/m-1 (OC) and 0.120 to 0.160 mg/m-3 (EC) with OC:EC ratios of 10 to 18, respectively. Smoldering fire conditions showed smoke plume OC and EC levels of 0.570--1.030 mg/m-3 (OC) and 0.006--0.050 mg/m-3 (EC) and much higher ratios of OC:EC (21 to 95). These aerosol data indicate the formation of EC particles is greatest during full-fire combustion of boreal forest material relative to smoldering combustion. However, EC particles comprise a minor fraction of the particulate carbon smoke aerosols for both full-fire and smoldering conditions; the major component of carbonaceous smoke aerosols emitted during the prescribed burn is OC. Overall, the OC and EC in-plume smoke aerosol data show nonuniform production of these particles during various stages of the prescribed burn, and major differences in the type of carbonaceous aerosol that is generated (OC versus EC)

  14. Preservation of ancient impact ages on the R chondrite parent body: 40Ar/39Ar age of hornblende-bearing R chondrite LAP 04840

    Science.gov (United States)

    Righter, K.; Cosca, M. A.; Morgan, L. E.

    2016-07-01

    The hornblende- and biotite-bearing R chondrite LAP 04840 is a rare kind of meteorite possibly containing outer solar system water stored during metamorphism or postshock annealing deep within an asteroid. Because little is known regarding its age and origin, we determined 40Ar/39Ar ages on hornblende-rich separates of the meteorite, and obtained plateau ages of 4340(±40) to 4380(±30) Ma. These well-defined plateau ages, coupled with evidence for postshock annealing, indicate this meteorite records an ancient shock event and subsequent annealing. The age of 4340-4380 Ma (or 4.34-4.38 Ga) for this and other previously dated R chondrites is much older than most impact events recorded by ordinary chondrites and points to an ancient event or events that predated the late heavy bombardment that is recorded in so many meteorites and lunar samples.

  15. Liquefaction of solid carbonaceous material with catalyst recycle

    Science.gov (United States)

    Gupta, Avinash; Greene, Marvin I.

    1992-01-01

    In the two stage liquefaction of a carbonaceous solid such as coal wherein coal is liquefied in a first stage in the presence of a liquefaction solvent and the first stage effluent is hydrogenated in the presence of a supported hydrogenation catalyst in a second stage, catalyst which has been previously employed in the second stage and comminuted to a particle size distribution equivalent to 100% passing through U.S. 100 Mesh, is passed to the first stage to improve the overall operation.

  16. Lithium storage into carbonaceous materials obtained from sugarcane bagasse

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Elaine Y.; Lala, Stella M.; Rosolen, Jose Mauricio, E-mail: rosolen@ffclrp.usp.b [University of Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Dept. of Chemistry

    2010-07-01

    Carbonaceous materials with different structures are prepared by carbonization of sugarcane bagasse. Depending on carbonization conditions, it is possible to obtain soot rich in flakes or in honeycomb-shaped micrometric particles, whose concentration has large influence on lithium storage into electrodes. The soot rich in honeycomb-shaped particles provides the best electrochemical performance, with a reversible specific capacity of 310 mAh g{sup -1}. The results suggest that the sugarcane bagasse can be potentially used in the design of anodic materials for lithium ion batteries. (author)

  17. Lithium storage into carbonaceous materials obtained from sugarcane bagasse

    International Nuclear Information System (INIS)

    Carbonaceous materials with different structures are prepared by carbonization of sugarcane bagasse. Depending on carbonization conditions, it is possible to obtain soot rich in flakes or in honeycomb-shaped micrometric particles, whose concentration has large influence on lithium storage into electrodes. The soot rich in honeycomb-shaped particles provides the best electrochemical performance, with a reversible specific capacity of 310 mAh g-1. The results suggest that the sugarcane bagasse can be potentially used in the design of anodic materials for lithium ion batteries. (author)

  18. Comets, carbonaceous meteorites, and the origin of the biosphere

    Directory of Open Access Journals (Sweden)

    r. b. Hoover

    2006-01-01

    Full Text Available The Biosphere is considered to represent the Earth's crust, atmosphere, oceans, and ice caps and the living organisms that survive within this habitat. This paper considers the significance of comets and carbonaceous meteorites to the origin and evolution of the Biosphere and presents new Field Emission Scanning Electron Microscope (FESEM images of indigenous microfossils in the Orgueil and Murchison meteorites. The discovery of microbial extremophiles in deep crustal rocks, hydrothermal vents and ancient ice has established that the biosphere is far more extensive than previously recognized. Chemical and molecular biomarkers and microfossils in Archaean rocks indicate that life appeared very early on the primitive Earth and the origin of the biosphere is closely linked with the emergence of life. The role of comets, carbonaceous meteorites, interstellar dust and asteroids in the delivery of water, organics and prebiotic chemicals to Earth during the Hadean (4.5–3.8 Ga period of heavy bombardment has become more widely recognized. Spacecraft observations of the chemical compositions and characteristics of the nuclei of several comets (Halley, Borrelly, Wild 2, and Tempel 1 have established that comets contain complex organic chemicals; that water is the predominant volatile; and that high temperatures (~400 K can be reached on the black (albedo~0.03 nuclei when near perihelion. The microscopic dust particles in the Tempel 1 ejecta are similar in size to the particulates of the Orgueil meteorite and evidence is mounting that comets may represent the parent bodies of the CI meteorites. Impact craters and pinnacles on comet Wild 2 suggest a thick crust. Episodic outbursts and jets of Halley, Borrelly, Wild 2 and Tempel 1 near perihelion indicate that localized regimes of liquid water may periodically exist beneath the thick crust of many comets. This increases the possibility that microbial life might survive in comets and therefore the

  19. Production of ferroan andesites by the experimental partial melting of an LL chondrite

    Science.gov (United States)

    Mcguire, J. C.; Jurewicz, A. J. G.; Jones, J. H.

    1994-01-01

    A partial melting experiment on the St. Severin (LL) chondrite produced a melt that was andesitic, having 54-60 wt% silica, at 1200 C and an oxygen fugacity of IW+2, two log units above the iron-wustite (IW) buffer. Under these same conditions, CV, CM, and L chondrites produced low-silica melts resembling angrites. This experimental study attempts to reproduce and explain this unusual result.

  20. Rhenium-osmium isotope systematics of ordinary chondrites and iron meteorites

    Science.gov (United States)

    Walker, R. J.; Morgan, J. W.; Horan, M. F.; Grossman, J. N.

    1993-01-01

    Using negative thermal ionization mass spectrometry, Re and Os abundances were determined by isotope dilution and Os-187/Os-186 measured in 11 ordinary chondrites, and also in 1 IIB and 3 IIIB irons. In addition, Os-186/Os-188 and Os-189/Os-188 ratios were precisely determined for 3 unspiked ordinary chondrites as a means of constraining the intensity of any neutron irradiation these meteorites may have experienced.

  1. Modal mineralogy of CI and CI-like chondrites by X-ray diffraction

    Science.gov (United States)

    King, A. J.; Schofield, P. F.; Howard, K. T.; Russell, S. S.

    2015-09-01

    The CI chondrites are some of the most hydrated meteorites available to study, making them ideal samples with which to investigate aqueous processes in the early Solar System. Here, we have used position-sensitive-detector X-ray diffraction (PSD-XRD) to quantify the abundance of minerals in bulk samples of the CI chondrite falls Alais, Orgueil and Ivuna, and the Antarctic CI-like chondrites Y-82162 and Y-980115. We find that Alais, Orgueil and Ivuna are dominated by a mixed serpentine/saponite phyllosilicate (81-84 vol%), plus minor magnetite (6-10%), sulphides (4-7%) and carbonates (500 °C. Similarly, Y-980115 contains disordered serpentine/saponite (71 vol%), sulphide (19%), olivine (8%) and magnetite (2%), confirming that it too is a thermally metamorphosed CI-like chondrite. We suggest that the CI-like chondrites are derived from a different parent body than the CI chondrites, which underwent short-lived thermal metamorphism due to impacts and/or solar radiation.

  2. Partial melting of ordinary chondrites: Lost City (H) and St. Severin (LL)

    Science.gov (United States)

    Jurewicz, Amy J. G.; Jones, John H.; Weber, Egon T.; Mittlefehldt, David W.

    1993-01-01

    Eucrites and diogenites are examples of asteroidal basalts and orthopyroxenites, respectively. As they are found intermingled in howardites, which are inferred to be regolith breccias, eucrites and diogenites are thought to be genetically related. But the details of this relationship and of their individual origins remain controversial. Work by Jurewicz et al. showed that 1170-1180 C partial melts of the (anhydrous) Murchison (CM) chondrite have major element compositions extremely similar to primitive eucrites, such as Sioux County. However, the MnO contents of these melts were about half that of Sioux County, a problem for the simple partial melting model. In addition, partial melting of Murchison could not produce diogenites, because residual pyroxenes in the Murchison experiments were too Fe- and Ca-rich and were minor phases at all but the lowest temperatures. A parent magma for diogenites needs an expanded low-calcium pyroxene field. In their partial melting study of an L6 chondrite, Kushiro and Mysen found that ordinary chondrites did have an expanded low-Ca pyroxene field over that of CV chondrites (i.e., Allende), probably because ordinary chondrites have lower Mg/Si ratios. This study expands that of both Kushiro and Mysen and Jurewicz et al. to the Lost City (H) and St. Severin (LL) chondrites at temperatures ranging from 1170 to 1325 C, at an fO2 of one log unit below the iron-wuestite buffer (IW-1).

  3. Hysteresis properties of ordinary chondrites and implications for their thermal history

    Science.gov (United States)

    Gattacceca, J.; Suavet, C. R.; Rochette, P.; Weiss, B. P.; Winklhofer, M.; Uehara, M.; Friedrich, J. M.

    2013-12-01

    We present a large dataset of magnetic hysteresis properties of ordinary chondrite falls. We show that hysteresis properties are distinctive of individual meteorites while homogeneous among meteorite subsamples. Except for the most primitive chondrites, these properties can be explained by a mixture of multidomain kamacite and tetrataenite (both in the cloudy zone and as larger grains in plessite and in the rim of zoned taenite). Kamacite dominates the induced magnetism whereas tetrataenite dominates the remanent magnetism, in agreement with previous microscopic magnetic observations. Type 5 and 6 chondrites have higher tetrataenite content than type 4 chondrites, suggesting they have lower cooling rates at least in the 650-450 °C interval, consistent with an onion-shell model. In equilibrated chondrites, shock-related transient heating events above ~500 °C result in the disordering of tetrataenite and associated drastic change in magnetic properties. As a good indicator of the amount of tetrataenite, hysteresis properties are a very sensitive proxy of the thermal history of ordinary chondrites, revealing low cooling rates during thermal metamorphism, and high cooling rates following shock reheating or excavation after thermal metamorphism.

  4. Ethanol and other oxygenateds from low grade carbonaceous resources

    Energy Technology Data Exchange (ETDEWEB)

    Joo, O.S.; Jung, K.D.; Han, S.H. [Korea Institute of Science and Technology, Seoul (Korea, Democratic People`s Republic of)] [and others

    1995-12-31

    Anhydrous ethanol and other oxygenates of C2 up can be produced quite competitively from low grade carbonaceous resources in high yield via gasification, methanol synthesis, carbonylation of methanol an hydrogenation consecutively. Gas phase carbonylation of methanol to form methyl acetate is the key step for the whole process. Methyl acetate can be produced very selectively in one step gas phase reaction on a fixed bed column reactor with GHSV over 5,000. The consecutive hydrogenation of methyl or ethyl acetate produce anhydrous ethanol in high purity. It is also attempted to co-produce methanol and DME in IGCC, in which low grade carbonaceous resources are used as energy sources, and the surplus power and pre-power gas can be stored in liquid form of methanol and DME during base load time. Further integration of C2 up oxygenate production with IGCC can improve its economics. The attempt of above extensive technology integration can generate significant industrial profitability as well as reduce the environmental complication related with massive energy consumption.

  5. Enantiomeric and Isotopic Analysis of Sugar Derivatives in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, George; Asiyo, Cynthia; Turk, Kendra; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    Several classes of organic compounds are found in carbonaceous meteorites including amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Such compounds are thought to have been delivered to the early Earth in asteroids and comets and may have played a role in the origin of life. Likewise, sugar derivatives are critical to all known lifeforms. Recent analyses of the Murchison and Murray carbonaceous meteorites revealed a diverse suite of such derivatives, i.e., sugar alcohols, and sugar acids. This presentation will focus primarily on the analysis of individual sugar acids - their enantiomeric and isotopic composition. Analysis of these compounds may reveal the nature of past (or present) meteoritic sugars themselves. For example, if parent sugars decomposed (by well-known mechanisms) to give the present acids, were their enantiomeric ratios preserved? Combined with other evidence, the enantiomeric composition of such compounds as glyceric acid and (especially) rare acids may help to answer such questions. C-13 and D isotope analysis of meteoritic sugar alcohols (glycerol, threitol, ribitol, etc.) as a group revealed that they were indigenous to the meteorite. Preliminary C-13 analysis of glyceric acid shows that it is also extraterrestrial.

  6. A new extraction process of carbonaceous refractory gold concentrate

    Institute of Scientific and Technical Information of China (English)

    MENG Yu-qun

    2005-01-01

    A new hydrometallurgical process for a carbonaceous refractory gold concentrate at ambient temperature and pressure was presented, including grinding-leaching, intensified alkaline leaching(IAL), thiosulfate leaching and cementation by zinc powder. The experimental results show that the grinding-leaching and intensified alkaline leaching process result in the selective oxidation of arsenopyrite and pyrite. The oxidation ratio of As is 96.6%, and 46.7 % for S. The total consumption of NaOH in alkaline leaching is only 28 % of that theoretically calculated under the conditions of full oxidization for the same amount of arsenopyrite and pyrite transforming into arsenates and sulfates, and 83. 6 % of gold is synchro-dissoluted by thiosulfate self-generated during pretreatment. Since the carbonaceous matter in concentrate possesses a strong capability of preg robbing, the cyanidation process is not suitable for the extraction of gold after pretreatment. However, the gold leaching rate by thiosulfate leaching for 24 h is increased to 91.7% from 0 - 3.2% by ultra-fine grinding without the pretreatment. The recovery of gold by zinc cementation gets to 99.6 %. Due to the thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal one.

  7. Metal-free carbonaceous electrocatalysts and photocatalysts for water splitting.

    Science.gov (United States)

    Xu, You; Kraft, Markus; Xu, Rong

    2016-05-31

    Water splitting driven by sunlight or renewable resource-derived electricity has attracted great attention for sustainable production of hydrogen from water. Current research interest in this field is focused on the development of earth-abundant photo- or electrocatalytic materials with high activity and long-term stability for hydrogen and/or oxygen evolution reactions. Due to their unique properties and characteristics, carbon and related carbon-based materials show great potential to replace some of the existing precious metal catalysts in water splitting technology. This tutorial review summarizes the recent significant progress in the fabrication and application of metal-free carbonaceous materials as photo- or electrocatalysts for water splitting. Synthetic strategies and applications of various carbonaceous materials, including graphitic carbon nitride (g-C3N4), graphene, carbon nanotubes (CNTs) as well as other forms of carbon-containing materials, for electrochemical or photochemical water splitting are presented, accompanied by a discussion of the key scientific issues and prospects for the future development of metal-free photo- and electrocatalysts. PMID:27094875

  8. Origins of interstellar and solar system: Carbonaceous materials

    Science.gov (United States)

    Feigelson, Eric D.

    1994-10-01

    Carbon is a crucial atom in cosmochemistry. It is well-established that carbon is synthesized in stellar interiors after the main sequence, is ejected by red giants as small carbonaceous grains during their 'carbon star' phase, resides in the interstellar medium, and was later incorporated into the solar system. The mechanisms of carbon grain formation and later chemical processing are complex because, with only small thermodynamic differences, carbon can take on a bewildering variety of forms: diamond; oxides; carbides; graphite; aliphatic hydrocarbons; polycyclic aromatic hydrocarbons (PAH's); fullerenes; amorphous carbon; and other compounds. These are evidence for many of the forms of carbon found in astronomical observations. We seek to understand the possible astrophysical sites and conditions of the origins of different forms of carbon by combining state-of-the-art capabilities of carbon chemistry with astrophysical modeling. The work is a collaboration between Prof. Frenklach, a leading carbon materials scientist with both laboratory and computer modeling expertise and Prof. Feigelson, an astrophysicist with interests in star formation. The largest effort under this grant was devoted to developing this concept into a comprehensive quantitative model. In addition to explaining the astronomical properties of red giants producing carbonaceous grains, our model also can incorporate recent meteoritic findings. Finally, our induced nucleation grain formation model provides a natural explanation for the widespread presence of PAH emission bands in the Galactic interstellar medium. A brief synopsis of other activities sponsored under this grant and a list of publications from this grant is included.

  9. Carbonaceous aerosols from different tropical biomass burning sources

    Science.gov (United States)

    Cachier, Hélène; Brémond, Marie-Pierre; Buat-Ménard, Patrick

    1989-08-01

    FOLLOWING a repetitive pattern, biomass burning affects the intertropical belt on a continental scale during the dry season1. The importance of these anthropogenic activities with regard to carbonaceous-component emissions into the global atmosphere is now well recognized2-4. It has been suggested that large injections of black carbon aerosols from the Tropics are of potential importance for the radiative and chemical balance of the troposphere5-10. Studies on carbonaceous aerosols have indicated that, on an annual basis, the intensity of the emissions from tropical biomass burning could compare with that of emissions from fossil-fuel burning in industrial countries7,8. Also, results from combustion chamber experiments have determined the important range of the emission factor for both the organic and the black carbon components of the aerosol1-16. Following on from our earlier studies on total atmospheric particulate carbon (Ct) and isotopic composition (δ13C) (ref. 2), we now present new data on the black carbon content (Cb) of atmospheric particles sampled during the biomass-burning season in the wooden savannah of the Ivory Coast. The Cb/Ct ratio is generally lower than expected and highly variable. This variability indicates that there are drastic changes in source apportionment, which from our isotope studies may be ascribed to the variety of vegetation fuel and also to the mode of combustion. Therefore the Cb/Ct ratio can potentially discriminate biomass-burning emissions from different tropical ecosystems.

  10. Sources of carbonaceous aerosol in the Amazon basin

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-03-01

    Full Text Available The quantification of sources of carbonaceous aerosol is important to understand their atmospheric concentrations and regulating processes and to study possible effects on climate and air quality, in addition to develop mitigation strategies.

    In the framework of the European Integrated Project on Aerosol Cloud Climate Interactions (EUCAARI fine (Dp < 2.5 μm and coarse (2.5 μm < Dp <10 μm aerosol particles were sampled from February to June (wet season and from August to September (dry season 2008 in the central Amazon basin. The mass of fine particles averaged 2.4 μg m−3 during the wet season and 4.2 μg m−3 during the dry season. The average coarse aerosol mass concentration during wet and dry periods was 7.9 and 7.6 μg m−3, respectively. The overall chemical composition of fine and coarse mass did not show any seasonality with the largest fraction of fine and coarse aerosol mass explained by organic carbon (OC; the average OC to mass ratio was 0.4 and 0.6 in fine and coarse aerosol modes, respectively. The mass absorbing cross section of soot was determined by comparison of elemental carbon and light absorption coefficient measurements and it was equal to 4.7 m2 g−1 at 637 nm. Carbon aerosol sources were identified by Positive Matrix Factorization (PMF analysis of thermograms: 44% of fine total carbon mass was assigned to biomass burning, 43% to secondary organic aerosol (SOA, and 13% to volatile species that are difficult to apportion. In the coarse mode, primary biogenic aerosol particles (PBAP dominated the carbonaceous aerosol mass. The results confirmed the importance of PBAP in forested areas.

    The source apportionment results were employed to evaluate the ability of global chemistry transport models to simulate carbonaceous aerosol sources in a regional tropical background site. The comparison showed an overestimation

  11. On the carbonaceous carriers of IR plateau and continuum emission

    CERN Document Server

    Papoular, Renaud

    2013-01-01

    This study explores the molecular origins of plateaus and continuum underlying IR and FIR bands emitted by compact nebulae, especially proto-planetary nebulae. Computational organic chemistry codes are used to deliver the vibrational integrated band intensities of various large, typical carbonaceous structures. These spectra are composed of a rather continuous distribution of weak modes from which emerge the fingerprints. The 6 to 18-mu region is interspersed with a great many weak lines, to which the plateaus are assigned. Similarly, the far IR spectrum is ascribed to the phonon (skeletal) spectrum which is readily identified beyond 18 mu. The absorptivities and absorption cross-sections per interstellar H atom deduced from these spectra are comparable with those of laboratory dust analogs and astronomical measurements, respectively. Moreover, the 5-35 mu spectra of two typical Proto-Planetary Nebula were reasonably well simulated with combinations of molecules containing functional groups which carry the 21...

  12. On thermodynamics of methane+carbonaceous materials adsorption

    KAUST Repository

    Rahman, Kazi Afzalur

    2012-01-01

    This study presents the theoretical frameworks for the thermodynamic quantities namely the heat of adsorption, specific heat capacity, entropy, and enthalpy for the adsorption of methane onto various carbonaceous materials. The proposed theoretical frameworks are developed from the rigor of thermodynamic property surfaces of a single component adsorbate-adsorbent system and by incorporating the micropore filling theory approach, where the effect of adsorbed phase volume is considered. The abovementioned thermodynamic properties are quantitatively evaluated from the experimental uptake data for methane adsorption onto activated carbons such as Maxsorb III at temperatures ranging from 120 to 350 K and pressures up to 25 bar. Employing the proposed thermodynamic approaches, this paper shows the thermodynamic maps of the charge and discharge processes of adsorbed natural gas (ANG) storage system for understanding the behaviors of natural gas in ANG vessel. © 2011 Elsevier Ltd. All rights reserved.

  13. In situ growth of copper nanocrystals from carbonaceous microspheres with electrochemical glucose sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaoliang; Yan, Zhengguang, E-mail: yanzg2004@gmail.com; Han, Xiaodong, E-mail: xdhan@bjut.edu.cn

    2014-02-01

    Graphical abstract: In situ growth of copper nanoparticles from hydrothermal copper-containing carbonaceous microspheres was induced by annealing or electron beam irradiation. Obtained micro-nano carbon/copper composite microspheres show electrochemical glucose sensing properties. - Highlights: • We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. • By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. • By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500 nm. • The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. - Abstract: In situ growth of copper nanocrystals from carbon/copper microspheres was observed in a well-controlled annealing or an electron beam irradiation process. Carbonaceous microspheres containing copper species with a smooth appearance were yielded by a hydrothermal synthesis using copper nitrate and ascorbic acid as reactants. When annealing the carbonaceous microspheres under inert atmosphere, copper nanoparticles were formed on carbon microspheres and the copper particle sizes can be increased to a range of 50–500 nm by altering the heating temperature. Similarly, in situ formation of copper nanocrystals from these carbonaceous microspheres was observed on the hydrothermal product carbonaceous microspheres with electron beam irradiation in a vacuum transmission electron microscopy chamber. The carbon/copper composite microspheres obtained through annealing were used to modify a glassy carbon electrode and tested as an electrochemical glucose sensor.

  14. In situ growth of copper nanocrystals from carbonaceous microspheres with electrochemical glucose sensing properties

    International Nuclear Information System (INIS)

    Graphical abstract: In situ growth of copper nanoparticles from hydrothermal copper-containing carbonaceous microspheres was induced by annealing or electron beam irradiation. Obtained micro-nano carbon/copper composite microspheres show electrochemical glucose sensing properties. - Highlights: • We synthesized carbonaceous microspheres containing non-nanoparicle copper species through a hydrothermal route. • By annealing or electron beam irradiation, copper nanoparticles would form from the carbonaceous microspheres in situ. • By controlling the annealing temperature, particle size of copper could be controlled in the range of 50–500 nm. • The annealed carbon/copper hierarchical composite microspheres were used to fabricate an electrochemical glucose sensor. - Abstract: In situ growth of copper nanocrystals from carbon/copper microspheres was observed in a well-controlled annealing or an electron beam irradiation process. Carbonaceous microspheres containing copper species with a smooth appearance were yielded by a hydrothermal synthesis using copper nitrate and ascorbic acid as reactants. When annealing the carbonaceous microspheres under inert atmosphere, copper nanoparticles were formed on carbon microspheres and the copper particle sizes can be increased to a range of 50–500 nm by altering the heating temperature. Similarly, in situ formation of copper nanocrystals from these carbonaceous microspheres was observed on the hydrothermal product carbonaceous microspheres with electron beam irradiation in a vacuum transmission electron microscopy chamber. The carbon/copper composite microspheres obtained through annealing were used to modify a glassy carbon electrode and tested as an electrochemical glucose sensor

  15. Adsorption of dyes onto carbonaceous materials produced from coffee grounds by microwave treatment.

    Science.gov (United States)

    Hirata, Mizuho; Kawasaki, Naohito; Nakamura, Takeo; Matsumoto, Kazuoki; Kabayama, Mineaki; Tamura, Takamichi; Tanada, Seiki

    2002-10-01

    Organic wastes have been burned for reclamation. However, they have to be recycled and reused for industrial sustainable development. Carbonaceous materials were produced from coffee grounds by microwave treatment. There are many phenolic hydroxyl and carboxyl groups on the surface of carbonaceous materials. The base consumption of the carbonaceous materials was larger than that of the commercially activated carbon. The carbonaceous materials produced from coffee grounds were applied to the adsorbates for the removal of basic dyes (methylene blue and gentian violet) in wastewater. This result indicated that the adsorption of dyes depended upon the surface polar groups on the carbonaceous materials. Moreover, the Freundlich constants of isotherms for the adsorption of methylene blue and gentian violet onto the carbonaceous materials produced from coffee grounds were greater than those for adsorption onto activated carbon or ceramic activated carbon. The interaction was greatest between the surface or porosity of the carbonaceous materials and methylene blue and gentian violet. The microwave treatment would be useful for the carbonization of organic wastes to save energy. PMID:12702420

  16. Cosmic-ray exposure ages of the ordinary chondrites and their significance for parent body stratigraphy

    Science.gov (United States)

    Crabb, J.; Schultz, L.

    1981-01-01

    Improved exposure ages are derived for 201 H, 203 L, and 38 LL chondrites in an effort to understand the characteristics of the chondrite parent body. The Ne-21 exposure ages were calculated from literature values taking into account shielding differences, a trapped component and radiogenic He. The exposure age distributions show clear peaks at 4.5 and 20 million years for the H chondrites, while the Ls and LLs appear more as a continuous series of intermediate peaks which may be modeled by at least six peaks between 1 and 35 million years in the case of L chondrites. The observations that every petrological type occurs in each large peak and contain solar wind gases suggest that the parent bodies have been fragmented and reassembled into a megabreccia. The H meteorites are proposed to represent the surface layer of a body with a substantial, active regolith as indicated by the relatively high abundances of solar gases. The L chondrites, on the other hand, are attributed to a parent body that was fragmented by collision about 500 million years ago.

  17. FIB-TEM Investigations of Fe-NI-Sulfides in the CI Chondrites Alais and Orgueil

    Science.gov (United States)

    Berger, Eve L.; Lauretta, D. S.; Zega, T. J.; Keller, L. P.

    2013-01-01

    The CI chondrites are primitive meteorites with bulk compositions matching the solar photosphere for all but the lightest elements. They have been extensively aqueously altered, and are composed primarily of fine-grained phyllosilicate matrix material which is host to carbonates, sulfates, sulfides, and minor amounts of olivine and pyroxene. The alteration, while extensive, is heterogeneous. For example, CI-chondrite cubanite and carbonate grains differ on mm to sub-mm scales, demonstrating multiple aqueous episodes. CI-chondrite variability is also evidenced by degree of brecciation, abundance and size of coarse-grained phyllosilicates, olivine and pyroxene abundance, as well as Ni-content and size of sulfide grains. Our previous work revealed Orgueil sulfide grains with variable Ni-contents, metal:S ratios, crystal structures and textures. We continue to explore the variability of CI-chondrite pyrrhotite (Po, (FeNi)1-xS) and pentlandite (Pn, (Fe,Ni)9S8) grains. We investigate the microstructure of sulfides within and among CI-chondrite meteorites in order to place constraints on the conditions under which they formed.

  18. Carbonaceous matters in epigenetic uranium deposits associated with zones of layer oxidation

    International Nuclear Information System (INIS)

    The paper presents investigations on the carbonaceous substances encountered in uranium deposits of a certain type. A set of methods (IR spectroscopy, ultimate analysis and others) was used to examine the various types of carbonaceous compounds, their composition, structure and geochemistry, and their role in the formation of uranium concentrations. All the carbonaceous substances are divided into two main groups according to their spacial distribution: those syngenetic to the ore-containing sediments; and epigenetic materials introduced into them as a result of the development of an ascending carbon-bitumen process. A considerable similarity was found between the compositions and properties of forms that are known to have no genetic relation to each other, while carbonaceous formations related by a common origin and belonging to the same group are represented by several modifications with different internal structures and compositons. All the carbonaceous compounds of the syngenetic group occur in a random relationships to the uranium mineralization. Nevertheless, the presence of syngenetic carbonaceous substances assists the formation of rich concentrations of uranium. The appearance of epigenetic carbonaceous substances (bitumens) is generally more closely spacially related to zones of development of uranium mineralization. The maximum concentrations of uranium are typical for hard insoluble bitumens. Among the soluble bitumens, the carbonaceous substances - bitumen S - bound in epigenetic materials, are most enriched in uranium (up to px10-3%). The role of the bitumens differs in the formation of displaced and primary uranium ores. In the first case, the significance of the bitumens, seems to lie in the reduction of the redox potential of the infiltrated uranium-bearing waters. In the second case, it is possible that a co-migration of uranium and certain types of carbonaceous substance (bitumen S, hard bitumen) took place in reducing (by iron) solutions

  19. Microbiological investigation of two chondrite meteorites: Murchison and Polonnaruwa

    Science.gov (United States)

    Pikuta, Elena V.; Lyu, Zhe; Whitman, William B.; LaBrake, Geneviev R.; Wallis, Jamie; Wickramarathne, Keerthi; Wickramasinghe, N. Chandra; Hoover, Richard B.

    2015-09-01

    The question of the contamination of meteorites by modern environmental microorganisms is an issue that has been raised since evidence for biological remains in carbonaceous meteorites was first published in the early 1960's.1-3 The contamination hypothesis has been raised for recent fossils of diatoms and filamentous cyanobacteria found embedded in the stones even though the nitrogen content of the fossils was below the 0.5% detection limit for Energy Dispersive X-ray Spectroscopy (EDS) of the Field Emission Scanning Electron Microscope. All modern biological contaminants should have nitrogen content in the detectable range of 2% to 20% indicating the remains are ancient fossils rather than living or Holocene cells. In our work, the possibility that extremophilic bacteria from our lab collection might be able to metabolize organic matter in the studied meteorites was tested. The potential toxic or inhibitory growth effects were also checked for different anaerobic cultures. UV exposed meteorite samples with consequent sterile extraction of the internal part were subjected to anaerobic cultivation techniques. As a result, eight anaerobic strains were isolated from internal and exterior parts of the studied meteorites. Preliminary results of their morphology, cytology, physiology, and molecular (16SrRNA sequencing) studies are presented and discussed in this article.

  20. Pressure gradient passivation of carbonaceous material normally susceptible to spontaneous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A.; Utz, Bruce R.

    2002-01-29

    This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.

  1. Pressure Gradient Passivation of Carbonaceous Material Normally Susceptible to Spontaneous Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A.; Utz, Bruce R.

    1999-07-15

    This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.

  2. Pyrolysis of carbonaceous particles and properties of Carbonaceous-g-Poly (acrylic acid-co-acrylamide superabsorbent polymer for agricultural applications

    Directory of Open Access Journals (Sweden)

    Ghazali S.

    2016-01-01

    Full Text Available Utilisation of fertilizer and water are very important in determining the production of agriculture nowadays. The excessive use of fertilizer in plantation somehow could leads to environmental pollution. The present study reported a synthesis of controlled release water retention (CRWR fertilizer coating with superabsorbent polymer (SAPs. Superabsorbent polymer (SAPs are polymers that have ability to absorb and retain large amounts of water relative to their own mass. The presence of coating layer of SAPs on fertilizer granules was believed could reduce excessive used of fertilizer by controlling their dissolution rates and also reduce the environmental pollution. In this study, the effect on the addition of carbonaceous filler in SAPs on the water absorbency was also be compared with control SAPs (without carbonaceous particles. In this study, the carbonaceous filler were obtained from pyrolysis process of empty fruit bunch (EFB biomass. The synthesized of SAPs and carbonaceous-SAPs were carried out via solution polymerization technique by using monomer of poly(acrylic acid (AA, acrylamide (AM, cross linker, methylene bisacrylamide (MBA and initiator, ammonium peroxodisulfate (APS that partially neutralized with sodium hydroxide (NaOH. The CRWR fertilizer was later be prepared by coated the fertilizer granule with SAPs and carbonaceous-SAPs. The water absorbency, morphology and the bonding formation of both CRWR fertilizer were investigated by using tea-beg method, Scanning Electron Microscopy (SEM and Fourier Transform Infrared Spectrophotometer (FTIR, respectively. Moreover, the water retention studies was conducted in order to investigate the efficiency of CRWR coated with SAP and carbonaceous-SAP in retaining the water content in different soil (organic and top soil. Based on the results, the CRWR fertilizer that was coated with carbonaceous-SAP had higher water absorbency value than the CRWR fertilizer without carbonaceous-SAP. Meanwhile

  3. Chondritic xenon in the Earth’s mantle

    Science.gov (United States)

    Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G.; Füri, Evelyn; Marty, Bernard

    2016-05-01

    Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth’s mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth’s mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth’s accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion.

  4. Sepctral Reflectance of Recently Fallen Chondrites and Some Igneous Rocks in China

    Institute of Scientific and Technical Information of China (English)

    林文祝; 高来之

    1991-01-01

    Polarization and radiation measurements and microwave studies show that the planets and the great majority of asteroids in the solar system are covered by soils similar to regolith on the moon surface.The soils repesent the composition of the asteroids and the geological elements of the planets. The spectral reflectance shows a tendency of decreasing from near ultraviolet,visible to near-infrared in order of LL→L→H→H with increasing Fe0/Fet rato and toward to absorption for Jilin,Xinyang and Zanoyang ordinary chondrites and Qinzhen enstatite chondrite recently fallen in China,The same chemical group of meteorites feature deeper absorption valleys with increasing metamorphic grade.The spectal reflectance of igneous rocks varies from strong to what is like that of H-group chondrites in order of acid→basic→ultrabasic rocks.

  5. Potassium-argon and iodine-xenon gas retention ages of enstatite chondrite meteorites

    International Nuclear Information System (INIS)

    Chondritic meteorites are generally considered to represent the most chemically primitive solar system material presently available for analysis. Within this group, based upon differences in the relative abundances of major elements, three types have been identified: Type I, Intermediate Type, and Type II. Radiometric ages of meteoritic material accordingly the evaluation of early solar system history by establishing a time scale over which various discrete and/or episodic events have occurred. In this work the potassium-argon (40Ar-39Ar) and iodine-xenon (I-Xe) radiometric dating techniques have been applied to a suite of enstatite chondrite meteorites. I-Xe relative gas retention ages were determined for seven enstatite chondrites

  6. Chemical zoning and homogenization of olivines in ordinary chondrites and implications for thermal histories of chondrules

    Science.gov (United States)

    Miyamoto, Masamichi; Mckay, David S.; Mckay, Gordon A.; Duke, Michael B.

    1986-01-01

    The extent and degree of homogenization of chemical zoning of olivines in type 3 ordinary chondrites is studied in order to obtain some constraints on cooling histories of chondrites. Based on Mg-Fe and CaO zoning, olivines in type 3 chondrites are classified into four types. A single chondrule usually contains olivines with the same type of zoning. Microporphyritic olivines show all four zoning types. Barred olivines usually show almost homogenized chemical zoning. The cooling rates or burial depths needed to homogenize the chemical zoning are calculated by solving the diffusion equation, using the zoning profiles as an initial condition. Mg-Fe zoning of olivine may be altered during initial cooling, whereas CaO zoning is hardly changed. Barred olivines may be homogenized during initial cooling because their size is relatively small. To simulated microporphyritic olivine chondrules, cooling from just below the liquidus at moderately high rates is preferable to cooling from above the liquidus at low rates. For postaccumulation metamorphism of type 3 chondrites to keep Mg-Fe zoning unaltered, the maximum metamorphic temperature must be less than about 400 C if cooling rates based on Fe-Ni data are assumed. Calculated cooling rates for both Fa and CaO homogenization are consistent with those by Fe-Ni data for type 4 chondrites. A hot ejecta blanket several tens of meters thick on the surface of a parent body is sufficient to homogenize Mg-Fe zoning if the temperature of the blanket is 600-700 C. Burial depths for petrologic types of ordinary chondrites in a parent body heated by Al-26 are broadly consistent with those previously proposed.

  7. Assessing the Formation of Ungrouped Achondrite Northwest Africa 8186: Residue, Crystallization Product, or Recrystallized Chondrite?

    Science.gov (United States)

    Srinivasan, P.; McCubbin, F. M.; Agee, C. B.

    2016-01-01

    The recent discoveries of primitive achondrites, metachondrites, and type 7 chondrites challenge the long held idea that all chondrites and achondrites form on separate parent bodies. These meteorites have experienced metamorphic temperatures above petrologic type 6 and have partially melted to various degrees. However, because of their isotopic and compositional similarities to both undifferentiated and differentiated groups, the provenance of these 'type 6+' meteorites remains largely unknown. CK and CV chondrites have recently been linked to a few achondrites due to their strong compositional, mineralogical, and isotopic similarities], suggesting a common origin between these meteorites. Although CVs have generally undergone low degrees of alteration near petrologic type 3, CKs have experienced a wide range of thermal alteration from petrologic type 3 to 6. Thermal evolution models on early accreting bodies predict that an early forming body can partially differentiate due to radiogenic heating, and, as a result, form radial layers of material increasing in thermal grade (types 3 to 6+) from the unmelted chondritic surface towards the differentiated core.Northwest Africa (NWA) 8186 is an ungrouped achondrite that provides compelling evidence for higher degrees of thermal processing and/or melting and differentiation on some CK/CV parent bodies. NWA 8186 plots on the CCAM line on a 3-oxygen isotope diagram directly with CK and CV chondrites and also plots with the CKs in regards to Cr isotopes. This meteorite is dominated by Nickel(II)Oxygen-rich olivine (less than 80%), lacks iron metal, and contains four oxide phases, indicating a high fOxygen (above FMQ) similar to the CKs. Additionally, NWA 8186 does not contain chondrules. We have further investigated the origins of NWA 8186 by examining and comparing the bulk composition of this CK-like achondrite with CK and CV chondrites, allowing us to assess the various scenarios in which NWA 8186 may have formed from

  8. Chondrites, S asteroids, and space weathering: Thumping noises from the coffin?

    Science.gov (United States)

    Fanale, F. P.; Clark, B. E.

    1993-01-01

    Most of the spectral characteristics of ordinary chondrites and S-asteroids in the visible and infrared can be reduced to three numerical values. These values represent the depth of the absorption band resulting from octahedrally coordinated Fe(sup 2+), the reflectance at 0.56 microns and the slope of the continuum (as measured according to convention). By plotting these three characteristics, it is possible to immediately compare the spectral characteristics of large numbers of ordinary chondrites and S-asteroids. Commonality of spectral characteristics between these populations can thus be evaluated on the basis of overlap in position on three two-coordinate systems: albedo vs. band depth, band depth vs. slope, and slope vs. albedo. In order to establish identity, members of the two populations must overlap on all three of these independent parameter spaces. In this coordinate system, spectra of 23 ordinary chondrites (representing all metamorphic grades), and 39 S-asteroids were compared. It was found that there was no overlap between the two populations in terms of the slope vs. band depth parameters, nor were most chondrites identical to the S-asteroids with respect to the other criteria. However, the controversial question remains: Where are the parent bodies of the chondrites? Perhaps an even more critical question is: Where are our samples of the S-asteroids? Considering the geography of the asteroid belt and the theory that early solar-system electromagnetic induction heating differentiated protoasteroids in the inner portion of the main belt, it was suggested that although S-asteroids and ordinary chondrites have very similar mineralogy, the S-asteroids are mixtures of metallic nickel iron and silicates which resulted from magmatism induced by electromagnetic heating whereas chondrites were only slightly metamorphosed nebular condensates. In this scenario chondrites would have been derived from a population of bodies with thermal lag times so short that

  9. Aluminum-26 in calcium-aluminum-rich inclusions and chondrules from unequilibrated ordinary chondrites

    OpenAIRE

    Huss, Gary R.; MacPherson, Glenn J.; Wasserburg, G. J.; Russell, Sara S.; Srinivasan, Gopalan

    2001-01-01

    In order to investigate the distribution of ^(26)A1 in chondrites, we measured aluminum-magnesium systematics in four calcium-aluminum-rich inclusions (CAIs) and eleven aluminum-rich chondrules from unequilibrated ordinary chondrites (UOCs). All four CAIs were found to contain radiogenic ^(26)Mg (^(26)Mg^*) from the decay of ^(26)A1. The inferred initial ^(26)Al/^(27)Al ratios for these objects ((^(26)Al/^(27)Al)_0 ≅ 5 × 10^(−5)) are indistinguishable from the (^(26)Al/^(27)Al)_0 ratios found...

  10. Evidence from the Semarkona ordinary chondrite for 26Al heating of small planets

    International Nuclear Information System (INIS)

    We report the first observation of radiogenic 26Mg in non-refractory meteoritic material, a plagio-clase-bearing, olivine-pyroxene clast chondrule in the Semarkona ordinary chondrite. The inferred initial abundance of 26Al is sufficient to produce incipient melting in well insulated bodies of chondritic composition. We conclude that planetary accretion and differentiation must have begun on a timescale comparable to the half life of 26Al and that, even if widespread melting did not occur, 26Al heating played a significant role in thermal metamorphism on small planets. (author)

  11. 40Ar - 39Ar dating of meteorites and the history of chondrite parent bodies

    International Nuclear Information System (INIS)

    The 40Ar-39Ar analyses of eleven ordinary chondrites and the unique meteorite Pontylyfni are presented. Results of previous 40Ar-39Ar age analyses have shown that the uncertainty in the calculated ages arises principally from the difficulties of interpretation of release patterns obtained from stepped heating experiments. For this reason considerable attention is paid to identifying the causes of complicating features in the age spectra. The ages obtained range from 4.52Ga to a lower limit of 4.38Ga and it is inferred that these date the time of cooling of the chondrites after formation and metamorphism. (author)

  12. Fullerenes in asphaltenes and other carbonaceous materials: natural constituents or laser artifacts.

    Science.gov (United States)

    Santos, Vanessa G; Fasciotti, Maíra; Pudenzi, Marcos A; Klitzke, Clécio F; Nascimento, Heliara L; Pereira, Rosana C L; Bastos, Wagner L; Eberlin, Marcos N

    2016-04-25

    The presence of fullerenes as natural constituents of carbonaceous materials or their formation as laser artifacts during laser desorption ionization (LDI) mass spectrometry (MS) analysis is reinvestigated and reviewed. The results using asphaltene samples with varying composition as well as standard polycyclic aromatic hydrocarbons (PAH) and fullerene samples as models have demonstrated that indeed Cn ring fullerenes are not natural constituents but they are formed as common and often as predominant artifacts upon laser radiation, and a series of incorrect assignments based on LDI-MS data of several carbonaceous materials seems unfortunately to have been made. When the present results are evaluated also in the light of the vast literature on LDI-MS of carbonaceous materials, the formation of fullerene artifacts seems particularly common for LDI-MS analysis of asphaltenes and other carbonaceous samples with considerably high levels of PAH and varies according to the type of laser used, and the intensity of the laser beam. PMID:26805430

  13. Composition of carbonaceous material that can be obtained by carbonisation of a clay-supported biopolymer

    OpenAIRE

    Ruiz-Hitzky, Eduardo; Moreira Martins Fernandes, Francisco Miguel

    2011-01-01

    [EN] The invention relates to a composition of carbonaceous material, characterised in that it comprises carbonaceous material supported on clay, said clay preferably being of the laminar type, such as montmorillonite, saponite, beidellite, stevensite, illite and combinations thereof, or a fibrous clay, such as sepiolite, palygorskite and combinations thereof. Said composition can be obtained by means of the carbonisation treatment of at least one biopolymer, such as chitosan, alginate, pecti...

  14. A study of carbonaceous char oxidation in air by semi-quantitative FTIR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koch, A.; Krzton, A.; Finqueneisel, G.; Heintz, O.; Weber, J.-V.; Zimny, T. [IUT Saint-Avold (France). Departement Chimie

    1998-05-01

    The paper describes the methodology of semi-quantitative characterization of coal-derived carbonaceous material oxidized under mild thermal conditions. Infrared spectroscopic analysis was applied to the determination of chemical changes induced by oxidation. A curve fitting model has thus been developed to evidence the evolution of specific chemical groups during treatment. The possibility to follow mechanisms and kinetics of carbonaceous char oxidation through data obtained by this model has been demonstrated. 28 refs., 7 figs., 2 tabs.

  15. Thermoluminescence and the shock and reheating history of meteorites. IV - The induced TL properties of type 4-6 ordinary chondrites

    Science.gov (United States)

    Haq, Munir; Hasan, Fouad A.; Sears, Derek W. G.

    1988-01-01

    The thermoluminescence (TL) properties were measured in 121 equilibrated H and L ordinary chondrites of which 33 H and 32 L were from Antarctica. It was found that the distribution of TL sensitivities for non-Antarctic L chondrites differs from that of non-Antarctic H chondrites, reflecting the well-known differences in shock history between L and H classes, the greater proportion of the former having suffered postmetamorphic shock. The data also show differences in TL sensitivity between Antarctic and non-Antarctic H chondrites, suggesting nontrivial differences in thermal history of these chondrites.

  16. Generation of oil from coal and carbonaceous shale

    Energy Technology Data Exchange (ETDEWEB)

    Kirkland, D.W.; Tsui, T.F.; Stockton, M.L.

    1987-05-01

    Coal and carbonaceous shale contain the remains of higher terrestrial (vascular) plants, remains commonly referred to as Type III kerogen. Given sufficient thermal exposure, such organic matter is commonly considered to generate only natural gas. Coaly sequences, however, are not always strictly gas producers. Many coaly sequences, particularly those of Tertiary age, have generated important volumes of oil. Those oils are usually paraffinic and waxy, or naphthenic; have a pristane-to-phytane ratio of 2-12; contain definitive biomarkers such as tricyclic diterpenoids; and are low in sulfur (much less than 1%). These oils are clearly distinct from those derived predominantly from marine algal remains. The principal source sequences of oils derived from coaly material occur in Tertiary deltas. Such source sequences contain abundant coaly material with favorable generative quality. Evaluation of generative quality is based either on geochemical analysis (e.g., atomic H/C > 0.9) or on petrographic analysis: source potential being proportional to the abundance and hydrogen richness of organic constituents (macerals). In approximate ranking, oil-generating potential of the hydrogen-rich macerals is exudatinite > alginite > resinite > liptodetrinite > cutinite > sporinite > vitrinite-B (fluorescing vitrinite). Examples of basins containing both a major Tertiary deltaic sequence (hundreds of cubic miles) and major volumes of oil (billions of barrels) derived predominantly from higher terrestrial plate remains are: the Ardjuna and Kutei basins, Indonesia; and the Gippsland basin, Australia.

  17. Home-made carbonaceous adsorbents for the iodine filter

    International Nuclear Information System (INIS)

    Assuming, that at the moment, an activated charcoal is the most widely used adsorbent in off-gas cleaning systems for elemental iodine removal, it was analyzed how to improve the adsorption properties of this filter material for removing the organic iodine compounds, especially in the presence of high relative humidity. Three different indigenous activated charcoals were selected for studies: two kinds of charcoal, designated as type A and N, as well as the charcoals used for flue gas desulfurization, as the third type S. These charcoals were impregnated with tin iodide (SnI2), potassium iodide (KI) and triethylenediamine (TEDA). Considering the results of the laboratory tests of the efficiency methyl iodide retention by the impregnated charcoals, it was concluded, that the carbonaceous adsorbent containing 1+1.5% KI showed efficient retention of the methyl iodide (CH3I), compared with, for example, foreign activated charcoals, as, NORIT-CGI 1% KI (West Germany) and GA-1 0.5% KI (Czechoslovakia). (author)

  18. High and rapid alkali cation storage in ultramicroporous carbonaceous materials

    Science.gov (United States)

    Yun, Young Soo; Lee, Seulbee; Kim, Na Rae; Kang, Minjee; Leal, Cecilia; Park, Kyu-Young; Kang, Kisuk; Jin, Hyoung-Joon

    2016-05-01

    To achieve better supercapacitor performance, efforts have focused on increasing the specific surface area of electrode materials to obtain higher energy and power density. The control of pores in these materials is one of the most effective ways to increase the surface area. However, when the size of pores decreases to a sub-nanometer regime, it becomes difficult to apply the conventional parallel-plate capacitor model because the charge separation distance (d-value) of the electrical double layer has a similar length scale. In this study, ultramicroporous carbonaceous materials (UCMs) containing sub-nanometer-scale pores are fabricated using a simple in situ carbonization/activation of cellulose-based compounds containing potassium. The results show that alkali cations act as charge carriers in the ultramicropores (<0.7 nm), and these materials can deliver high capacitances of ∼300 F g-1 at 0.5 A g-1 and 130 F g-1, even at a high current rate of 65 A g-1 in an aqueous medium. In addition, the UCM-based symmetric supercapacitors are stable over 10,000 cycles and have a high energy and power densities of 8.4 Wh kg-1 and 15,000 W kg-1, respectively. This study provides a better understanding of the effects of ultramicropores in alkali cation storage.

  19. Measurement of carbonaceous aerosol with different sampling configurations and frequencies

    Directory of Open Access Journals (Sweden)

    Y. Cheng

    2015-03-01

    Full Text Available Carbonaceous aerosol in Beijing, China was measured with different sampling configurations (denuded vs. un-denuded and frequencies (24 vs. 48 h averaged. Our results suggest that the negative sampling artifact of a bare quartz filter could be remarkably enhanced due to the uptake of water vapor by the filter medium, indicating that the positive sampling artifact tends to be underestimated under high humidity conditions. It was also observed that the analytical artifact (i.e., the underestimation of elemental carbon by the operationally defined value of the thermal-optical method was more apparent for the low frequency samples such that their elemental carbon (EC concentrations were about 15% lower than the reference values measured by the high-frequency, denuded filters. Moreover, EC results of the low frequency samples were found to exhibit a stronger dependence on the charring correction method. In addition, optical attenuation (ATN of EC was retrieved from the carbon analyzer, and the low frequency samples were shown to be more significantly biased by the shadowing effect.

  20. Temperature and Oxygen Fugacity Constraints on CK and R Chondrites and Implications for Water and Oxidation in the Early Solar System

    Science.gov (United States)

    Righter, K.; Neff, K. E.

    2007-01-01

    Recent chondritic meteorite finds in Antarctica have included CB, CH, CK and R chondrites, the latter two of which are among the most oxidized materials found in meteorite collections. In this study we present petrographic and mineralogic data for a suite of CK and R chondrites, and compare to previous studies of CK and R, as well as some CV chondrites. In particular we focus on the opaque minerals magnetite, chromite, sulfides, and metal as well as unusual silicates hornblende, biotite, and plagioclase. Several mineral thermometers and oxy-barometers are utilized to calculate temperatures and oxygen fugacities for these unusual meteorites compared to other more common chondrite groups. R and CK chondrites show lower equilibrium temperatures than ordinary chondrites, even though they are at similar petrologic grades (e.g., thermal type 6). Oxygen fugacity calculated for CV and R chondrites ranges from values near the iron-wustite (IW) oxygen buffer to near the fayalite-magnetite-quartz (FMQ) buffer. In comparison, the fO2 recorded by ilmenite-magnetite pairs from CK chondrites are much higher, from FMQ+3.1 to FMQ+5.2. The latter values are the highest recorded for materials in meteorites, and place some constraints on the formation conditions of these magnetite-bearing chondrites. Differences between mineralogic and O isotopic compositions of CK and R chondrites suggest two different oxidation mechanisms, which may be due to high and low water: rock ratios during metamorphism, or to different fluid compositions, or both.

  1. Determination of 11 major and minor elements in chondritic meteorites by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Wolf, Stephen F; Compton, Joseph R; Gagnon, Christopher J L

    2012-10-15

    We have developed a new method for the quantification of 11 major and minor elements (Na, Mg, Al, P, S, K, Ca, Cr, Mn, Fe, and Ni) in chondritic meteorites by ICPMS using external calibration with a matrix-matched standard prepared from the Allende Standard Reference Meteorite. We have demonstrated the method's accuracy and assessed three different measures of precision by performing replicate dissolutions and analyses of 0.10-g samples of a homogenized samples of the CM2 meteorite Murchison and compared our results to literature values. We subsequently applied this method to the analysis of a set of four chondritic meteorites possessing a relatively wide range of chondritic compositions with results in accord with previously published values. Because our method is designed to use the same instrumentation and can use samples and standards prepared according to methods previously validated for the determination of a comprehensive suite of minor, trace, moderately and highly volatile trace elements (i.e., Li, Sc, Ti, V, Mn, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ru, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, all 14 naturally occurring lanthanoids, Hf, W, Re, Ir, Pt, Tl, Bi, Th, and U) it complements these methods and allows a single laboratory to determine the concentrations of 60 elements in semimicroscopic amounts of chondritic material. PMID:23141337

  2. Trace-element abundances and the origin of aluminum-26-bearing chondrules in unequilibrated ordinary chondrites

    OpenAIRE

    Huss, G. R.; Wasserburg, G. J.; Russell, S.S.; MacPherson, G. J.

    1997-01-01

    Calcium-aluminum-rich inclusions (CAis) typically contain radiogenic ^(26)Mg (^(26)Mg^*) from the decay of ^(26)Al, with (^(26)Al/^(27)Al); up to 5 x 10^(-5) [e.g., 1]. Some Al-rich chondrules from unequilibrated ordinary chondrites contain detectable ^(26)Mg^*, but (^(26)Al/^(27)Al); is lower [e.g., 2].

  3. A Petrologic and bulk Chemical Characterization of the Unequilibrated Ordinary Chondrite Northwest Africa 5717

    Science.gov (United States)

    Bigolski, J. N.; Friedrich, J. M.; Weisberg, M. K.; O'Keefe, M.-C.

    2014-09-01

    We examine the chemical group affinities of Northwest Africa 5717 (Type 3.05) in terms of its petrologic and bulk chemical characteristics and test its apparent dual lithology. Preliminary data suggest it to be related to L- and LL-chondrites.

  4. Trace element evidence for contrastive thermal histories of H4-6 and L4-6 chondrite parent bodies

    Energy Technology Data Exchange (ETDEWEB)

    Lingner, D.W.

    1985-01-01

    Earlier studies at Purdue revealed that tertiary shock (impact) heating is the main post-accretionary fractionation process for mobile and siderophilic trace elements in L4-6 chondrites. Lower contents of these elements in samples evidencing shock are attributable to loss (transport in an Fe-Ni-S eutectic or volatilization from collisional debris) upon breakup of the L parent body 500-650 Myr ago. Reported here are new radiochemical neutron activation analysis results for Ag, As, Au, Bi, Cd, Co, Cs, Ga, In, K, Rb, Sb, Se, Te, Tl and Zn in H4-6 chondrites as a function of /sup 40/Ar retention (a reliable shock indicator in L chondrites). Mobile element depletion in H chondrites with undisturbed /sup 40/Ar vs. unshocked L chondrites indicates a hotter environment (a shock event or higher accretion temperatures) for the former. Siderophiles are enriched in H relative to L chondrites, as expected. Within the H chondrite population, trace element relationships with /sup 40/Ar retention and petrologic type are complex and puzzling. These are discussed in detail in light of several proposed parent body models.

  5. Impact of carbonaceous aerosol emissions on regional climate change

    Science.gov (United States)

    Roeckner, E.; Stier, P.; Feichter, J.; Kloster, S.; Esch, M.; Fischer-Bruns, I.

    2006-11-01

    The past and future evolution of atmospheric composition and climate has been simulated with a version of the Max Planck Institute Earth System Model (MPI-ESM). The system consists of the atmosphere, including a detailed representation of tropospheric aerosols, the land surface, and the ocean, including a model of the marine biogeochemistry which interacts with the atmosphere via the dust and sulfur cycles. In addition to the prescribed concentrations of carbon dioxide, ozone and other greenhouse gases, the model is driven by natural forcings (solar irradiance and volcanic aerosol), and by emissions of mineral dust, sea salt, sulfur, black carbon (BC) and particulate organic matter (POM). Transient climate simulations were performed for the twentieth century and extended into the twenty-first century, according to SRES scenario A1B, with two different assumptions on future emissions of carbonaceous aerosols (BC, POM). In the first experiment, BC and POM emissions decrease over Europe and China but increase at lower latitudes (central and South America, Africa, Middle East, India, Southeast Asia). In the second experiment, the BC and POM emissions are frozen at their levels of year 2000. According to these experiments the impact of projected changes in carbonaceaous aerosols on the global mean temperature is negligible, but significant changes are found at low latitudes. This includes a cooling of the surface, enhanced precipitation and runoff, and a wetter surface. These regional changes in surface climate are caused primarily by the atmospheric absorption of sunlight by increasing BC levels and, subsequently, by thermally driven circulations which favour the transport of moisture from the adjacent oceans. The vertical redistribution of solar energy is particularly large during the dry season in central Africa when the anomalous atmospheric heating of up to 60 W m-2 and a corresponding decrease in surface solar radiation leads to a marked surface cooling, reduced

  6. Dating recent lake sediments using spheroidal carbonaceous particle (SCP)

    Institute of Scientific and Technical Information of China (English)

    WU Yanhong; WANG Sumin; XIA Weilan; LIU Jian

    2005-01-01

    Dating lake sediment using sedimentary event is the supplement and calibration to traditional dating by radionuclide such as 210Pb and 137Cs. Based on the change of spheroidal carbonaceous particle (SCP) concentration, the age sequence of lake sediments can be deduced. It is one of the dating methods using sedimentary event. SCP is formed from combustion of fossil fuel at high temperature up to 1750℃ and at a rate of heating of approaching 104 ℃/s. It can be dispersed to several hundred kilometers away from its source and deposited with precipitation or dryly deposited, and kept in sediments. Compared with Cs or Pb, there is no evidence for SCP that it decays in lake sediments and is un-removable once stored except by physical disturbance because it is mainly composed of element carbon. Handy method to extract, identify and calculate has been developed. Although fossil fuel has been used early in China, combustion at high temperature started later since emergence of electricity generation. The productivity of SCP is positively related with the generated thermal power, which is reflected as the SCP concentration in lake sediments increases with the increase of generated thermal power. Therefore, reliable sediment markers from the start of the SCP record and the remarkable variation can be used for dating purpose. In China, electricity industry started from the 1950s, and rapid increase of generated power took place since 1978. Based on these time markers, SCP time sequences of lake sediment cores LH and LL-4 from Longgan Lake, the middle reach of the Yangtze River, have been established, which is comparable with the results from 137Cs and 210Pb, and has eliminated the errors of dating using 137Cs and 210Pb.

  7. Springtime warming and reduced snow cover from carbonaceous particles

    Directory of Open Access Journals (Sweden)

    M. G. Flanner

    2008-11-01

    Full Text Available Boreal spring climate is uniquely susceptible to solar warming mechanisms because it has expansive snow cover and receives relatively strong insolation. Carbonaceous particles can influence snow coverage by warming the atmosphere, reducing surface-incident solar energy (dimming, and reducing snow reflectance after deposition (darkening. We apply a range of models and observations to explore impacts of these processes on springtime climate, drawing several conclusions: 1 Nearly all atmospheric particles (those with visible-band single-scatter albedo less than 0.999, including all mixtures of black carbon (BC and organic matter (OM, increase net solar heating of the atmosphere-snow column. 2 Darkening caused by small concentrations of particles within snow exceeds the loss of absorbed energy from concurrent dimming, thus increasing solar heating of snowpack as well (positive net surface forcing. Over global snow, we estimate 6-fold greater surface forcing from darkening than dimming, caused by BC+OM. 3 Equilibrium climate experiments suggest that fossil fuel and biofuel emissions of BC+OM induce 95% as much springtime snow cover loss over Eurasia as anthropogenic carbon dioxide, a consequence of strong snow-albedo feedback and large BC+OM emissions from Asia. 4 Of 22 climate models contributing to the IPCC Fourth Assessment Report, 21 underpredict the rapid warming (0.64°C decade−1 observed over springtime Eurasia since 1979. Darkening from natural and anthropogenic sources of BC and mineral dust exerts 3-fold greater forcing on springtime snow over Eurasia (3.9 W m−2 than North America (1.2 W m−2. Inclusion of this forcing significantly improves simulated continental warming trends, but does not reconcile the low bias in rate of Eurasian spring snow cover decline exhibited by all models.

  8. Spatial and seasonal variability of carbonaceous aerosol across Italy

    Science.gov (United States)

    Sandrini, Silvia; Fuzzi, Sandro; Piazzalunga, Andrea; Prati, Paolo; Bonasoni, Paolo; Cavalli, Fabrizia; Bove, Maria Chiara; Calvello, Mariarosaria; Cappelletti, David; Colombi, Cristina; Contini, Daniele; de Gennaro, Gianluigi; Di Gilio, Alessia; Fermo, Paola; Ferrero, Luca; Gianelle, Vorne; Giugliano, Michele; Ielpo, Pierina; Lonati, Giovanni; Marinoni, Angela; Massabò, Dario; Molteni, Ugo; Moroni, Beatrice; Pavese, Giulia; Perrino, Cinzia; Perrone, Maria Grazia; Perrone, Maria Rita; Putaud, Jean-Philippe; Sargolini, Tiziana; Vecchi, Roberta; Gilardoni, Stefania

    2014-12-01

    This paper analyses elemental (EC), organic (OC) and total carbon (TC) concentration in PM2.5 and PM10 samples collected over the last few years within several national and European projects at 37 remote, rural, urban, and traffic sites across the Italian peninsula. The purpose of the study is to obtain a picture of the spatial and seasonal variability of these aerosol species in Italy, and an insight into sources, processes and effects of meteorological conditions. OC and EC showed winter maxima and summer minima at urban and rural locations and an opposite behaviour at remote high altitude sites, where they increase during the warm period due to the rising of the Planetary Boundary Layer (PBL). The seasonal averages of OC are higher during winter compared to summer at the rural sites in the Po Valley (from 1.4 to 3.5 times), opposite to what usually occurs at rural locations, where OC increases during the warm period. This denotes the marked influence of urban areas on the surrounding rural environment in this densely populated region. The different types of sites exhibit marked differences in the average concentrations of carbonaceous aerosol and OC/EC ratio. This ratio is less sensitive to atmospheric processing than OC and EC concentrations, and hence more representative of different source types. Remote locations are characterised by the lowest levels of OC and especially EC, with OC/EC ratios ranging from 13 to 20, while the maximum OC and EC concentrations are observed at road-traffic influenced urban sites, where the OC/EC ratio ranges between 1 and 3. The highest urban impacts of OC and EC relative to remote and rural background sites occur in the Po Valley, especially in the city of Milan, which has the highest concentrations of PM and TC and low values of the OC/EC ratio.

  9. Analyses and characterization of fossil carbonaceous materials for silicon production

    Energy Technology Data Exchange (ETDEWEB)

    Myrvaagnes, Viktor

    2008-01-15

    Production of high silicon alloys is carried out in submerged arc furnaces by reduction of silicon bearing oxides (typically quartz) with carbon materials. Carbonaceous materials like coal, coke, charcoal and woodchips are commonly used as reduction materials in the process. Primarily based on historical prices of charcoal compared to fossil reduction materials, the Norwegian Ferroalloy Industry has mostly been using coal and coke (char) as the source of carbon. From a process point of view, the most important role of the carbonaceous material is to react with SiO gas to produce SiC. The ability of the reduction materials to react with SiO gas can be measured and the value is recognized as the reactivity of the carbon source. Reactivity is one of the most important parameters in the smelting process and is commonly acknowledged to strongly affect both productivity and specific energy consumption. The main objectives of this work has been to establish methods to characterize the material properties of fossil carbonaceous reduction materials used in the silicon process and to evaluated how these properties affect the reactivity towards SiO gas. In order to accomplish these objectives, three run of mine (ROM) single seam coals which are particularly well suited for ferroalloy production were selected. Two Carboniferous coals from USA (Blue Gem) and Poland (Staszic) with similar rank, but significantly different composition as well as a Permian coal from Australia (Peak Downs) have been characterized by chemical- and petrographical methods. Blue Gem is a homogeneous coal, low in mineral inclusions and macerals of the inertinite group and determined to have a random vitrinite reflectance of 0.71 %. Staszic has a similar reflectance of vitrinite (0.72 %), but is determined to be a very inhomogeneous coal with both inertinite macerals and minerals embedded in the vitrinite matrix. Peak Downs has a random reflectance of vitrinite of 1.32 % and is hence the coal sample of

  10. A 3.6-b.y.-old impact-melt rock fragment in the Plainview chondrite: Implications for the age of the H-group chondrite parent body regolith formation

    International Nuclear Information System (INIS)

    Major, minor, trace and REE abundances as well as mineralogical and textural properties of a light-colored, poikilitic, metallic nickel-iron- and troilite-poor lithic fragment in the brecciated Plainview, Texas, H5 chondrite unambiguously show that the fragment is of H-group chondrite parentage, despite its non-chondritic texture and appearance. 40Ar-39Ar age dating indicates that the fragment is 3.63 b.y. old, whereas the Plainview host chondrite is 4.4 b.y. old. The fragment's texture and certain mineral compositions, such as relatively high CaO in olivine and orthopyroxene, the presence of alkali-rich feldspar and interstitial material, and metallic nickel-iron of Ni contents of 10-15 wt.% (martensite), indicate that the fragment formed by relatively fast cooling from a melt. (orig./ME)

  11. Efficacy of carbonaceous nanocomposites for sorbing ionizable antibiotic sulfamethazine from aqueous solution.

    Science.gov (United States)

    Zhang, Chen; Lai, Cui; Zeng, Guangming; Huang, Danlian; Yang, Chunping; Wang, Yang; Zhou, Yaoyu; Cheng, Min

    2016-05-15

    This paper investigated the key factors and mechanisms of sulfamethazine (SMT) sorption on a novel carbonaceous nanocomposite, and the effects of harsh aging on SMT sorption in the presence and absence of soil and before as well as after aging. The carbonaceous nanocomposites were synthesized by dip-coating straw biomass in carboxyl functionalized multi-walled carbon nanotubes solution and then pyrolyzed at 300 °C and 600 °C in the absence of air. The sorption performance of high temperature carbonaceous nanocomposite on SMT was excellent, as measured sorption distribution coefficient in the order of 10(3)-10(5.5) L kg(-1). Carbonaceous nanocomposites were aged either alone or mixed with soil via exposure to nutrients and soil extract (biological aging) or 80 °C for 100 d (chemical aging). No obvious effects of harsh aging on SMT sorption were observed in the presence of soil and/or biological and chemical aging. The primary mechanisms for SMT sorption included partition caused by Van der Waals forces and adsorption caused by hydrogen bonding and π-π electron-donor-acceptor interaction. Comprehensively considering the cost, renewability, and the application to real water samples, the carbonaceous nanocomposites have potential in removal of SMT and possibly other persistent organic pollutants from wastewater. PMID:26986499

  12. Silicone-grafted carbonaceous nanotubes with enhanced dispersion stability and electrorheological efficiency

    International Nuclear Information System (INIS)

    Carbonaceous particles are types of important fillers or dispersed phases of electro-responsive electrorheological (ER) suspensions. But carbonaceous particles, in particular with nano-order size, are easy to aggregate in oils. This characteristic limits the application of ER suspensions based on carbonaceous particles. In order to improve dispersion stability and ER efficiency, in this paper, we develop silicone-grafted carbonaceous nanotubes (CTs) by grafting oxidized carbonaceous nanotubes with epoxy-terminated silicone. The samples are characterized by Fourier transform infrared spectra, x-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy. The wettability and dispersion stability of nanotubes in silicone oil are investigated by wetting curves and sedimentation tests. The ER properties of CTs when dispersed in silicone oil are measured by a rheometer under electric fields. It demonstrates that grafting with silicone can distinctly improve the wettability of CTs in silicone oil and decrease the re-aggregation of CTs. As a result, the suspension of silicone-grafted CTs in silicone oil shows high dispersion stability. Compared to the suspension of bare CTs, the suspension of silicone-grafted CTs exhibits lower zero-field viscosity but higher field-induced viscosity; thus it possesses higher ER efficiency. This enhanced ER efficiency is related to the improved wettability of silicone-grafted CTs in silicone oil. (paper)

  13. Preparation and characterization of a new carbonaceous material for electrochemical systems

    Directory of Open Access Journals (Sweden)

    ZI JI LIN

    2010-02-01

    Full Text Available A new carbonaceous material was successfully prepared by the py-rolysis of scrap tire rubber at 600 °C under a nitrogen atmosphere. The physical characteristics of the prepared carbonaceous material were studied by scanning electron microscopy (SEM, X-ray powder diffraction (XRD and X-ray photoelectron spectroscopy (XPS. It was proved that the carbonaceous material had a disordered structure and spherical morphology with an average particle size about 100 nm. The prepared carbonaceous material was also used as electrodes in electrochemical systems to examine its electrochemical performances. It was demonstrated that it delivered a lithium insertion capacity of 658 mA h g-1 during the first cycle with a coulombic efficiency of 68 %. Cyclic voltammograms test results showed that a redox reaction occurred during the cycles. The chemical diffusion coefficient based on the impedance diagram was about 10-10 cm2 s-1. The pyrolytic carbonaceous material derived from scrap tire rubber is therefore considered to be a potential anode material in lithium secondary batteries or capacitors. Furthermore, it is advantageous for environmental protection.

  14. Reactive Oxygen-Doped 3D Interdigital Carbonaceous Materials for Li and Na Ion Batteries.

    Science.gov (United States)

    Fan, Ling; Lu, Bingan

    2016-05-01

    Carbonaceous materials as anodes usually exhibit low capacity for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). Oxygen-doped carbonaceous materials have the potential of high capacity and super rate performance. However, up to now, the reported oxygen-doped carbonaceous materials usually exhibit inferior electrochemical performance. To overcome this problem, a high reactive oxygen-doped 3D interdigital porous carbonaceous material is designed and synthesized through epitaxial growth method and used as anodes for LIBs and SIBs. It delivers high reversible capacity, super rate performance, and long cycling stability (473 mA h g(-1) after 500 cycles for LIBs and 223 mA h g(-1) after 1200 cycles for SIBs, respectively, at the current density of 1000 mA g(-1) ), with a capacity decay of 0.0214% per cycle for LIBs and 0.0155% per cycle for SIBs. The results demonstrate that constructing 3D interdigital porous structure with reactive oxygen functional groups can significantly enhance the electrochemical performance of oxygen-doped carbonaceous material. PMID:27061155

  15. Facile preparation of magnetic carbonaceous nanoparticles for Pb2+ ions removal.

    Science.gov (United States)

    Nata, Iryanti Fatyasari; Salim, Giyanto Wijaya; Lee, Cheng-Kang

    2010-11-15

    Magnetic carbonaceous nanoparticles were prepared by a facile two-step solution phase thermal synthesis. Magnetic nanoparticles (MNPs) with size less than 100 nm were first generated from FeCl(3) in a solvothermal reaction. The size could be significantly reduced to approximately 30 nm when 1,6-hexanediamine was employed in the reaction solution to functionalize the surface of MNPs with amine. Both the plain and amine-functionalized MNPs (MH) were effectively encapsulated in the carbonaceous shell by hydrothermal treatment in 0.5 M glucose solution. The saturation magnetization of MH decreased significantly from 70 to 25 emu/g after carbonaceous shell was formed. The as-prepared magnetic carbonaceous nanoparticles (MH@C) carries a negative surface charge (-30 mV) at neutral pH and has a point of zero charge (PZC) at pH 2. The carbonaceous shell not only can protect the magnetic nanoparticles (MNP) from the corrosive environment but also possesses a high adsorption capacity towards Pb(II). The adsorption isotherm at room temperature can be well-fitted by Langmuir model with a maximum adsorption capacity of 123 mg/g. PMID:20800347

  16. Oxygen Isotopic and Petrological Constraints on the Origin and Relationship of IIE Iron Meteorites and H Chondrites

    Science.gov (United States)

    McDermott, K. H.; Greenwood, R. C.; Franchi, I. A.; Anand, M.; Scott, E. R. D.

    2011-03-01

    New oxygen isotopic measurements of IIEs and H chondrites are indistinguishable — strengthening a possible common origin for these groups. Combining oxygen results with mineralogy, the nature of their parent body or bodies can be explored.

  17. TL sensitivity of single chondrules from type 3 chondrites: Thermal metamorphism of chondrules in a nebular environment?

    International Nuclear Information System (INIS)

    Chondrules are millimeter sized near spherical objects that comprise >50% of the volume of chondritic meteorites. Determinations of the initial 26Al/27Al ratios from earlier studies of ferromagnesian chondrules in unequilibriated ordinary chondrites indicate that most chondrules formed between ∼1.5 and 2.5 Ma after the formation of calcium-aluminium rich inclusions (CAIs) in the early solar system. This paper investigates the thermoluminescence sensitivity of chondrules from unequilibriated ordinary chondrites to search for indications of thermal metamorphism in a pre-parent body. Our results suggest that a few chondrules in Semarkona and Bishunpur chondrites with higher levels of TL sensitivity may have experienced such thermal metamorphism in a pre-parent body environment

  18. Preparation of a Sulfonated Carbonaceous Material from Lignosulfonate and Its Usefulness as an Esterification Catalyst

    Directory of Open Access Journals (Sweden)

    Duckhee Lee

    2013-07-01

    Full Text Available Sulfonated carbonaceous material useful as a solid acid catalyst was prepared from lignosulfonate, a waste of the paper-making industry sulfite pulping process, and characterized by 13C-NMR, FT-IR, TGA, SEM and elemental analysis, etc. The sulfonic acid group density and total density of all acid groups in the sulfonated carbonaceous material was determined by titration to be 1.24 mmol/g and 5.90 mmol/g, respectively. Its catalytic activity in the esterification of cyclohexanecarboxylic acid with anhydrous ethanol was shown to be comparable to that of the ionic exchange resin Amberlyst-15, when they were used in the same amount. In the meantime, the sulfonic acid group was found to be leached out by 26%–29% after it was exposed to hot water (95 °C for 5 h. The catalytic usefulness of the prepared carbonaceous material was investigated by performing esterifications.

  19. Temporal and spatial evolution pattern of carbonaceous-siliceous-argillaceous rock type uranium deposits in China

    International Nuclear Information System (INIS)

    Carbonaceous-siliceous-argillaceous uranium deposits in China are controlled spatially by the continental margin rift valley systems, borderland basin systems and epicontinental active downfaulted aulacogen systems. And large-scale uranium mineralization is controlled by uraniferous marine carbonaceous-siliceous-argillaceous rock, which was settled down with submarine backwash and submarine volcanic eruption in margin rift valley and continental margin rifting mineralizing environment. Its positional distribution is restricted by the driving force of hydrothermal fluid superposition and transformation and is affected by the fault in the boundary of red basin related to uranium deposit. The spatial location of uranium ore body is controlled by subsidiary fracture, interstratal fracture zone and combined fault belt, which are derived by discordogenic fault linked to uraniferous construction of marine carbonaceous-siliceous-argillaceous rock. The age of uranium mineralization is accordant with tectonic-magmatic action which drove the hydrothermal fluid to superpose and transform the uraniferous formation. (authors)

  20. Genesis and organic geochemical characteristics of the carbonaceous rock stratabound gold deposits, South China

    Institute of Scientific and Technical Information of China (English)

    胡凯; 翟建平; 刘英俊; 王鹤年; 张景荣; 贾蓉芬

    2000-01-01

    The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits, respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high. The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic carbon and gold of the host rocks appear to syndeposit in situ during the formation of the gold-bearing formations. The organic carbon played

  1. Tunable atomic force microscopy bias lithography on electron beam induced carbonaceous platforms

    Directory of Open Access Journals (Sweden)

    Narendra Kurra

    2013-09-01

    Full Text Available Tunable local electrochemical and physical modifications on the carbonaceous platforms are achieved using Atomic force microscope (AFM bias lithography. These carbonaceous platforms are produced on Si substrate by the technique called electron beam induced carbonaceous deposition (EBICD. EBICD is composed of functionalized carbon species, confirmed through X-ray photoelectron spectroscopy (XPS analysis. AFM bias lithography in tapping mode with a positive tip bias resulted in the nucleation of attoliter water on the EBICD surface under moderate humidity conditions (45%. While the lithography in the contact mode with a negative tip bias caused the electrochemical modifications such as anodic oxidation and etching of the EBICD under moderate (45% and higher (60% humidity conditions respectively. Finally, reversible charge patterns are created on these EBICD surfaces under low (30% humidity conditions and investigated by means of electrostatic force microscopy (EFM.

  2. Springtime warming and reduced snow cover from carbonaceous particles

    Directory of Open Access Journals (Sweden)

    M. G. Flanner

    2009-04-01

    Full Text Available Boreal spring climate is uniquely susceptible to solar warming mechanisms because it has expansive snow cover and receives relatively strong insolation. Carbonaceous particles can influence snow coverage by warming the atmosphere, reducing surface-incident solar energy (dimming, and reducing snow reflectance after deposition (darkening. We apply a range of models and observations to explore impacts of these processes on springtime climate, drawing several conclusions: 1 Nearly all atmospheric particles (those with visible-band single-scatter albedo less than 0.999, including all mixtures of black carbon (BC and organic matter (OM, increase net solar heating of the atmosphere-snow column. 2 Darkening caused by small concentrations of particles within snow exceeds the loss of absorbed energy from concurrent dimming, thus increasing solar heating of snowpack as well (positive net surface forcing. Over global snow, we estimate 6-fold greater surface forcing from darkening than dimming, caused by BC+OM. 3 Equilibrium climate experiments suggest that fossil fuel and biofuel emissions of BC+OM induce 95% as much springtime snow cover loss over Eurasia as anthropogenic carbon dioxide, a consequence of strong snow-albedo feedback and large BC+OM emissions from Asia. 4 Of 22 climate models contributing to the IPCC Fourth Assessment Report, 21 underpredict the rapid warming (0.64°C decade−1 observed over springtime Eurasia since 1979. Darkening from natural and anthropogenic sources of BC and mineral dust exerts 3-fold greater forcing on springtime snow over Eurasia (3.9 W m−2 than North America (1.2 W m−2. Inclusion of this forcing significantly improves simulated continental warming trends, but does not reconcile the low bias in rate of Eurasian spring snow cover decline exhibited by all models, likely because BC deposition trends are negative or near-neutral over much of Eurasia. Improved Eurasian

  3. Pyrolysis oil from carbonaceous solid wastes in Malaysia

    International Nuclear Information System (INIS)

    The agro-industrial sector of Malaysia produces a huge amount of oil palm and paddy rice. These generate a significant amount of renewable biomass solid wastes in the forms of oil palm shell and rice husk. Apart from this a huge quantity of scrap tyre is generated from the country's faster increasing usage of transportation vehicles like motorcycle, car, bus and lorries. These wastes are producing pollution and disposal problems affecting the environment. Besides energy is not recovered efficiently from these waste resources. From the elemental composition and thermogravimetric analysis (TGA) studies of the wastes, it appeared that the wastes could be used for pyrolysis liquid oil production. Pyrolysis at present is deemed to be a potential method for the conversion of carbonaceous solid wastes into upgraded liquid products which can either be tried for liquid fuel or value-added chemical. A fluidized bed bench scale fast pyrolysis system was employed for this thermochemical conversion process of solid wastes. Silica sand was used as fluidized bed material and nitrogen gas as the fluidising medium. The products obtained were liquid oil, solid char and gas. The liquid oil and solid char were collected separately while the gas was flared. The maximum liquid product yield was found to vary with feedstock material fluidized bed temperature. The maximum liquid product yield was found to be 58, 53 and 40 wt. % of biomass fed at fluidized bed temperature at 500, 525 and 4500C respectively for oil palm shell, scrap tyre and rice husk. The solid char yield was 25, 36 and 53 wt. % of biomass fed at the condition of maximum liquid product yield for oil palm shell, scrap tyre and rice husk respectively. The oil products were subjected to FTIR, GC and GC/MS analysis for their group composition and detailed chemical compositions. The pyrolysis oil from scrap tyre was found to contain highest percentage of pure hydrocarbons (25 wt. % of total feed) with esters and oxygenated

  4. Microfossils and biomolecules in carbonaceous meteorites: possibility of life in water-bearing asteroids and comets

    Science.gov (United States)

    Hoover, Richard B.

    2014-09-01

    It is well established that carbonaceous meteorites contain water, carbon, biogenic elements and a host of organic chemicals and biomolecules. Several independent lines of evidence indicate that the parent bodies of the CI1 and CM2 carbonaceous meteorites are most probably the C-type asteroids or cometary nuclei. Several of the protein amino acids detected in the meteorites exhibit chirality and have an excess of the L-enantiomer -- such as in the amino acids present in the proteins of all known life forms on Earth. Isotopic studies have established that the amino acids and nucleobases in the CI1 and CM2 carbonaceous meteorites are both indigenous and extraterrestrial. Optical and Scanning Electron Microscopy studies carried out by researchers during the past half century have revealed the presence of complex biogenic microstructures embedded in the rock-matrix of many of carbonaceous meteorites similar to extinct life-forms known as acritarchs and hystrichospheres. Carbonaceous meteorites also contain a wide variety of large filaments that exhibit the complex morphologies and correct size ranges of known genera and species of photosynthetic microorganisms such as cyanobacteria and diatoms. However, EDAX investigations have shown that these carbon-rich filaments typically have nitrogen content below the level of detection (hair and teeth of Pleistocene Mammoths. Hence, the absence of detectable nitrogen in the filaments provides direct evidence that they do not represent recent biological contaminants that invaded these meteorite stones after they were observed to fall to Earth. The spectral and fluorescence properties of pigments found in several species of terrestrial cyanobacteria which are similar to some microfossils found in carbonaceous meteorites may provide valuable clues to help search for evidence for biomolecules and life on the icy moons of Jupiter and Saturn, asteroids and comets.

  5. Biomass-derived sponge-like carbonaceous hydrogels and aerogels for supercapacitors.

    Science.gov (United States)

    Wu, Xi-Lin; Wen, Tao; Guo, Hong-Li; Yang, Shubin; Wang, Xiangke; Xu, An-Wu

    2013-04-23

    As a newly developed material, carbon gels have been receiving considerable attention due to their multifunctional properties. Herein, we present a facile, green, and template-free route toward sponge-like carbonaceous hydrogels and aerogels by using crude biomass, watermelon as the carbon source. The obtained three-dimensional (3D) flexible carbonaceous gels are made of both carbonaceous nanofibers and nanospheres. The porous carbonaceous gels (CGs) are highly chemically active and show excellent mechanical flexibility which enable them to be a good scaffold for the synthesis of 3D composite materials. We synthesized the carbonaceous gel-based composite materials by incorporating Fe3O4 nanoparticles into the networks of the carbonaceous gels. The Fe3O4/CGs composites further transform into magnetite carbon aerogels (MCAs) by calcination. The MCAs keep the porous structure of the original CGs, which allows the sustained and stable transport of both electrolyte ions and electrons to the electrode surface, leading to excellent electrochemical performance. The MCAs exhibit an excellent capacitance of 333.1 F·g(-1) at a current density of 1 A·g(-1) within a potential window of -1.0 to 0 V in 6 M KOH solution. Meanwhile, the MCAs also show outstanding cycling stability with 96% of the capacitance retention after 1000 cycles of charge/discharge. These findings open up the use of low-cost elastic carbon gels for the synthesis of other 3D composite materials and show the possibility for the application in energy storage. PMID:23548083

  6. Process for the production of hydrogen and electricity from carbonaceous fuels and process heat

    International Nuclear Information System (INIS)

    This patent application concerns the simultaneous production of hydrogen and electricity from carbonaceous fuels and process heat. An acid formed from a non-metallic oxide or a mixture of a halogen and water are used as the oxygen carrier for the combustion of the carbonaceous fuel at a high pressure. The combustion gases are pressure relieved in a turbine to generate electricity. The chemical components required for forming the initial material (acid or mixture of water and halogen) are separated from the waste gas. These processes have distinct advantages compared with previously introduced processes for producing hydrogen and electricity. (orig.)

  7. Chondrites isp. Indicating Late Paleozoic Atmospheric Anoxia in Eastern Peninsular India

    Directory of Open Access Journals (Sweden)

    Biplab Bhattacharya

    2014-01-01

    Full Text Available Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting. Monospecific assemblage of marine trace fossil Chondrites isp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin in eastern peninsular India signifies predominant marine incursion during end early Permian. Monospecific Chondrites ichnoassemblage in different sedimentary horizons in geographically wide apart (~400 km areas demarcates multiple short-spanned phases of anoxia in eastern India. Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

  8. Experimental Space Weathering of Ordinary Chondrites by Nanopulse Laser: TEM Results

    Science.gov (United States)

    Noble, S. K.; Hiroi, T.; Keller, L. P.; Pieters, C. M.

    2011-01-01

    A set of ordinary chondrite meteorites has been subjected to artificial space weathering by nanopulse laser to simulate the effects of micrometeorite bombardment. Three meteorites, an H (Ehole), L (Chateau Renard - CR), and LL (Appley Bridge - AB) were lasered following the method of Sasaki et al [1]. Near IR spectra were taken before and after exposure to examine the optical changes induced and the samples were examined by scanning and transmission electron microscopy (SEM and TEM) to understand the physical changes.

  9. The natural thermoluminescence of meteorites. V - Ordinary chondrites at the Allan Hills ice fields

    Science.gov (United States)

    Benoit, P. H.; Sears, H.; Sears, D. W. G.

    1993-02-01

    Natural thermoluminescence (TL) data have been obtained for 167 ordinary chondrites from the ice fields in the vicinity of the Allan Hills in Victoria Land, Antarctica, in order to investigate their thermal and radiation history, pairing, terrestrial age, and concentration mechanisms. Natural TL values for meteorites from the Main ice field are fairly low, while the Farwestern field shows a spread with many values 30-80 krad, suggestive of less than 150-ka terrestrial ages. There appear to be trends in TL levels within individual ice fields which are suggestive of directions of ice movement at these sites during the period of meteorite concentration. These directions seem to be confirmed by the orientations of elongation preserved in meteorite pairing groups. The proportion of meteorites with very low natural TL levels at each field is comparable to that observed at the Lewis Cliff site and for modern non-Antarctic falls and is also similar to the fraction of small perihelia orbits calculated from fireball and fall observations. Induced TL data for meteorites from the Allan Hills confirm trends which show that a select group of H chondrites from the Antarctic experienced a different extraterrestrial thermal history to that of non-Antarctic H chondrites.

  10. Minor and trace element concentrations in adjacent kamacite and taenite in the Krymka chondrite

    Science.gov (United States)

    Meftah, N.; Mostefaoui, S.; Jambon, A.; Guedda, E. H.; Pont, S.

    2016-04-01

    We report in situ NanoSIMS siderophile minor and trace element abundances in individual Fe-Ni metal grains in the unequilibrated chondrite Krymka (LL3.2). Associated kamacite and taenite of 10 metal grains in four chondrules and one matrix metal were analyzed for elemental concentrations of Fe, Ni, Co, Cu, Rh, Ir, and Pt. The results show large elemental variations among the metal grains. However, complementary and correlative variations exist between adjacent kamacite-taenite. This is consistent with the unequilibrated character of the chondrite and corroborates an attainment of chemical equilibrium between the metal phases. The calculated equilibrium temperature is 446 ± 9 °C. This is concordant with the range given by Kimura et al. (2008) for the Krymka postaccretion thermal metamorphism. Based on Ni diffusivity in taenite, a slow cooling rate is estimated of the Krymka parent body that does not exceed ~1K Myr-1, which is consistent with cooling rates inferred by other workers for unequilibrated ordinary chondrites. Elemental ionic radii might have played a role in controlling elemental partitioning between kamacite and taenite. The bulk compositions of the Krymka metal grains have nonsolar (mostly subsolar) element/Ni ratios suggesting the Fe-Ni grains could have formed from distinct precursors of nonsolar compositions or had their compositions modified subsequent to chondrule formation events.

  11. The use of SEM/EDS method in mineralogical analysis of ordinary chondritic meteorite

    Directory of Open Access Journals (Sweden)

    Breda Mirtič

    2009-12-01

    Full Text Available The aim of this study was to evaluate the potential of scanning electron microscopy coupled with energy dispersiveX-ray spectroscopy (SEM/EDS for determination of mineral phases according to their stoichiometry and assessment of mineral composition of ordinary chondritic meteorite. For the purposes of this study, H3 type ordinary chondritic meteorite Abbott was selected. SEM/EDS allows identification and characterisation of mineralphases, whose size is below the resolution of an optical microscope. Mineral phases in chondrules and interstitial matrix were located in backscattered electron (BSE mode and were assessed from atomic proportions of constituent elements, obtained by the EDS analysis. SEM/EDS analyses of mineral phases showed that Abbott meteorite is characterised by Fe-rich (Fe, Ni-alloy kamacite, Fe-sulphide troilite or pyrrhotite, chromite, Mg-rich olivine, orthopyroxene bronzite or hypersthene, clinopyroxene Al-diopside, acid plagioclase oligoclase, accessory mineral chlorapatite and secondary minerals Fe-hydroxides (goethite or lepidocrocite. Results of semi-quantitative analyses confirmed that most of analysed mineralphases conform well to stoichiometric minerals with minor deviations of oxygen from stoichiometric proportions. Comparison between mineral phases in chondrules and interstitial matrix was also performed, however it showed no significant differences in elemental composition.Differences in chemical composition between minerals in interstitial matrix and chondrules are sometimes too small to be discernedby the SEM/EDS, therefore knowledge of SEM/EDS capabilities is important for correct interpretation of chondrite formation.

  12. Nebular dead zone effects on the D/H ratio in chondrites and comets

    CERN Document Server

    Ali-Dib, Mohamad; Petit, Jean-Marc; Mousis, Olivier; Vernazza, Pierre; Lunine, Jonathan I

    2015-01-01

    Comets and chondrites show non-monotonic behaviour of their Deuterium to Hydrogen (D/H) ratio as a function of their formation location from the Sun. This is difficult to explain with a classical protoplanetary disk model that has a decreasing temperature structure with radius from the Sun. We want to understand if a protoplanetary disc with a dead zone, a region of zero or low turbulence, can explain the measured D/H values in comets and chondrites. We use time snapshots of a vertically layered disk model with turbulent surface layers and a dead zone at the midplane. The disc has a non-monotonic temperature structure due to increased heating from self-gravity in the outer parts of the dead zone. We couple this to a D/H ratio evolution model in order to quantify the effect of such thermal profiles on D/H enrichment in the nebula. We find that the local temperature peak in the disk can explain the diversity in the D/H ratios of different chondritic families. This disk temperature profile leads to a non-monoton...

  13. Phosphate control on the Th/U variations in ordinary chondrites: Improving solar system abundances

    Science.gov (United States)

    Goreva, J. S.; Burnett, D. S.

    2001-01-01

    Isotope dilution thorium and uranium analyses by inductively-coupled plasma mass spectrometry of 12 samples of Harleton (L6) show a much larger scatter than was previously observed in equilibrated ordinary chondrites. Th/U linearly correlates with 1/U in Harleton and in the total equilibrated ordinary chondrite data set as well. Such a correlation suggests a two component mixture and this trend can be quantitatively modeled as reflecting variations in the mixing ratio between two phosphate phases: chlorapatite and merrillite. The major effect is due to apatite variations, which strongly control the whole rock U concentrations. Phosphorous variations will tend to destroy the Th/U vs. 1/U correlation, and measured P concentrations on exactly the same samples as U and Th show a factor of 3 range. It appears that the P variations are compensated by inverse variations in U (a dilution effect) to preserve the Th/U vs. 1/U correlation. Because variations in whole rock Th/U are consequences of phosphate sampling, a weighted average of high accuracy Th/U measurements in equilibrated ordinary chondrites should converge to a significantly improved average solar system Th/U. Our best estimate of this ratio is 3.53 with ?mean = 0.10.

  14. A petrographic, chemical, and isotopic study of calcium-aluminum-rich inclusions and aluminum-rich chondrules from the Axtell (CV3) chondrite

    OpenAIRE

    Srinivasan, G.; Huss, G. R.; Wasserburg, G. J.

    2000-01-01

    Petrographic, compositional, and isotopic characteristics were studied for three calcium-aluminum-rich inclusions (CAIs) and four plagioclase-bearing chondrules (three of them Al-rich) from the Axtell (CV3) chondrite. All seven objects have analogues in Allende (CV3) and other primitive chondrites, yet Axtell, like most other chondrites, contains a distinctive suite of CAIs and chondrules. In common with Allende CAIs, CAIs in Axtell exhibit initial ^(26)Al/^(27)Al ratios ((^(26)Al/^(27)Al)0) ...

  15. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  16. Direct Carbon Fuel Cell System Utilizing Solid Carbonaceous Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Turgut Gur

    2010-04-30

    This 1-year project has achieved most of its objective and successfully demonstrated the viability of the fluidized bed direct carbon fuel cell (FB-DCFC) approach under development by Direct Carbon technologies, LLC, that utilizes solid carbonaceous fuels for power generation. This unique electrochemical technology offers high conversion efficiencies, produces proportionately less CO{sub 2} in capture-ready form, and does not consume or require water for gasification. FB-DCFC employs a specialized solid oxide fuel cell (SOFC) arrangement coupled to a Boudouard gasifier where the solid fuel particles are fluidized and reacted by the anode recycle gas CO{sub 2}. The resulting CO is electrochemically oxidized at the anode. Anode supported SOFC structures employed a porous Ni cermet anode layer, a dense yttria stabilized zirconia membrane, and a mixed conducting porous perovskite cathode film. Several kinds of untreated solid fuels (carbon and coal) were tested in bench scale FBDCFC prototypes for electrochemical performance and stability testing. Single cells of tubular geometry with active areas up to 24 cm{sup 2} were fabricated. The cells achieved high power densities up to 450 mW/cm{sup 2} at 850 C using a low sulfur Alaska coal char. This represents the highest power density reported in the open literature for coal based DCFC. Similarly, power densities up to 175 mW/cm{sup 2} at 850 C were demonstrated with carbon. Electrical conversion efficiencies for coal char were experimentally determined to be 48%. Long-term stability of cell performance was measured under galvanostatic conditions for 375 hours in CO with no degradation whatsoever, indicating that carbon deposition (or coking) does not pose any problems. Similar cell stability results were obtained in coal char tested for 24 hours under galvanostatic conditions with no sign of sulfur poisoning. Moreover, a 50-cell planar stack targeted for 1 kW output was fabricated and tested in 95% CO (balance CO{sub 2

  17. Crystallography of hornblende amphibole in LAP04840 R chondrite and implication for its metamorphic history

    International Nuclear Information System (INIS)

    LAP04840 is an unusual R chondrite that includes abundant hornblende amphibole. LAP04840 shows a texture of equilibrated chondrite composed of 59.3% olivine, 13.5% orthopyroxene, 13.3% hornblende, 6.2% plagio-clase, 6.0% Fe-Ni sulfide, and 1.7% accessory minerals. Hornblende replaces olivine and pyroxene in both chondrules and matrices, suggesting its secondary origin. All major phases in LAP04840 are homogeneous: olivine (Fa37), orthopyroxene (En70Wo1), and plagioclase (An8Or2). Hornblende is also nearly homogeneous, but the total sum by electron microprobe analysis is 96-98 wt%, suggesting the presence of Fe3+ and a hydroxyl group. Synchrotron Fe-XANES analysis gives a Fe3+/ΣFe ratio of ∼0.6 and micro-FT-IR analysis confirms the presence of a hydroxyl group. Thus, the structural formula is (Na0.40K0.04) (Ca1.46Mn0.02Fe0.062+Na0.46) (Al0.08Fe0.432+Fe0.753+Cr0.08Mg3.60) (Si7.02Al0.98)O22(OH)2. Single crystal X-ray diffraction of LAP04840 hornblende gives the following lattice constants: a=9.7957(9) A, b=18.0788(12) A, c=5.2949(5) A, β=104.747(3)deg. The relatively short distances of [M(1)-O=2.069 A], [M(2)-O=2.081 A], and [M(3)-O=2.058 A] suggest the feasible preference of small Fe3+ at these sites. The mineralogy and petrology of LAP04840 are consistent with its classification as an R6 chondrite. However, the presence of hornblende and biotite is quite unique among not only R chondrites but also asteroidal meteorites in general. The presence of these hydrous minerals suggests metamorphism under high pressure and an aqueous environment probably at depth in the parent body. A thermometer using hornblende and plagioclase equilibria gives T=670-690degC. Further, a barometer using Al content in hornblende gives P=∼0.1 GPa. Although these estimates bear some uncertainties, it is likely that the size of the R chondrite parent body was large enough to induce such metamorphism. (author)

  18. Carbonaceous Aerosols Emitted from Light-Duty Vehicles Operating on Gasoline and Ethanol Fuel Blends

    Science.gov (United States)

    This study examines the chemical properties of carbonaceous aerosols emitted from three light-duty gasoline vehicles (LDVs) operating on gasoline (e0) and ethanol-gasoline fuel blends (e10 and e85). Vehicle road load simulations were performed on a chassis dynamometer using the t...

  19. PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

    International Nuclear Information System (INIS)

    Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, KF (L kg-1) spanned several orders of magnitude, ranging from log KF of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

  20. Impact of anthropogenic emissions and open biomass burning on regional carbonaceous aerosols in South China

    International Nuclear Information System (INIS)

    Carbonaceous aerosols were studied at three background sites in south and southwest China. Hok Tsui in Hong Kong had the highest concentrations of carbonaceous aerosols (OC = 8.7 ± 4.5 μg/m3, EC = 2.5 ± 1.9 μg/m3) among the three sites, and Jianfeng Mountains in Hainan Island (OC = 5.8 ± 2.6 μg/m3, EC = 0.8 ± 0.4 μg/m3) and Tengchong mountain over the east edge of the Tibetan Plateau (OC = 4.8 ± 4.0 μg/m3, EC = 0.5 ± 0.4 μg/m3) showed similar concentration levels. Distinct seasonal patterns with higher concentrations during the winter, and lower concentrations during the summertime were observed, which may be caused by the changes of the regional emissions, and monsoon effects. The industrial and vehicular emissions in East, Southeast and South China, and the regional open biomass burning in the Indo-Myanmar region of Asia were probably the two major potential sources for carbonaceous matters in this region. - Anthropogenic emissions in China and open biomass burning in the Indo-Myanmar region were the two major potential sources for carbonaceous matters in South China region.

  1. Impact of anthropogenic emissions and open biomass burning on regional carbonaceous aerosols in South China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Gan, E-mail: zhanggan@gig.ac.c [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Jun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu Yue; Guo Lingli [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Tang Jianhui [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Lee, Celine S.L. [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Liu Xiang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen Yingjun [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2010-11-15

    Carbonaceous aerosols were studied at three background sites in south and southwest China. Hok Tsui in Hong Kong had the highest concentrations of carbonaceous aerosols (OC = 8.7 {+-} 4.5 {mu}g/m{sup 3}, EC = 2.5 {+-} 1.9 {mu}g/m{sup 3}) among the three sites, and Jianfeng Mountains in Hainan Island (OC = 5.8 {+-} 2.6 {mu}g/m{sup 3}, EC = 0.8 {+-} 0.4 {mu}g/m{sup 3}) and Tengchong mountain over the east edge of the Tibetan Plateau (OC = 4.8 {+-} 4.0 {mu}g/m{sup 3}, EC = 0.5 {+-} 0.4 {mu}g/m{sup 3}) showed similar concentration levels. Distinct seasonal patterns with higher concentrations during the winter, and lower concentrations during the summertime were observed, which may be caused by the changes of the regional emissions, and monsoon effects. The industrial and vehicular emissions in East, Southeast and South China, and the regional open biomass burning in the Indo-Myanmar region of Asia were probably the two major potential sources for carbonaceous matters in this region. - Anthropogenic emissions in China and open biomass burning in the Indo-Myanmar region were the two major potential sources for carbonaceous matters in South China region.

  2. Isotropic and high density carbon made from carbonaceous powder prepared by distillation under reduced pressure

    International Nuclear Information System (INIS)

    It is attempted to produce high density, high strength and isotropic carbon made from carbonaceous powder. The carbonaceous powder was prepared by carbonization of coal-tar pitch at a temperature of 440 - 5000C and subsequent distillation under reduced pressure. The distillation was performed at a temperature of 300 - 5000C below the carbonization temperature. In some cases additional quinoline extraction was carried out on the powder. Green carbon body was formed without binder pitch under isostatic pressure at room temperature. The body was heat-treated at a temperature of 1100 - 28000C. Bulk density, weight loss, shrinkage, strength, lattice parameter, crystallite size and BAF of the obtained carbon body were measured. It is confirmed that high density, high strength and isotropic carbon made from the carbonaceous powder and the following results were obtained. 1) BS (benzene soluble) fraction, β-resin (benzene insoluble and quinoline soluble) fraction and QI (quinoline insoluble) fraction were able to fractionate by distillation under reduced pressure. Concentration gradient of each fraction seems to exist in the carbonaceous powder. 2) Using the powder prepared by a lower temperature of the carbonization and/or the distillation, the carbon body had higher bulk density and higher strength. 3) The β-resin fraction had the effects of increasing the green density and enhancing the shrinkage of carbon body during the heat treatment. (author)

  3. Assessment of Artifacts in Filter Collections for Carbonaceous Aerosol and the Particulate Mass

    Czech Academy of Sciences Publication Activity Database

    Maenhaut, W.; Cafmeyer, J.; Chi, X.; Schwarz, Jaroslav

    2001, s. S673-S674. [European Aerosol Conference EAC 2001. Leipzig (DE), 03.09.2001-07.09.2001] Institutional research plan: CEZ:AV0Z4072921 Keywords : filter sampling * artifacts * carbonaceous aerosol Subject RIV: CF - Physical ; Theoretical Chemistry

  4. Magnetite in CI carbonaceous meteorites - Origin by aqueous activity on a planetesimal surface

    Science.gov (United States)

    Kerridge, J. F.; Mackay, A. L.; Boynton, W. V.

    1979-01-01

    The composition and morphology of magnetite in CI carbonaceous meteorites appear incompatible with a nebular origin. Mineralization on the meteorite parent body is a more plausible mode of formation. The iodine-xenon age of this material therefore dates an episode of secondary mineralization on a planetesimal rather than the epoch of condensation in the primitive solar nebula.

  5. Multivariate Statistical Analysis of Volatile Trace Elements in H Chondrites: Implications for Parent Body Structure

    Science.gov (United States)

    Wolf, S. F.; Lipschutz, M. E.

    1993-07-01

    The perception among meteoriticists is that contents of the volatile trace elements systematically decrease with shock and particularly petrologic type. This perception affects views that investigators have of the early history and structure of the H chondrite parent body. Measurement of a variety of volatile trace elements in a statistically significant number of samples accompanied by chemometric data analysis techniques developed for interpretation of trace- element data [1] should maximize the amount of genetic information available from the volatile trace elements and offer clues to the early thermal history of the H chondrite parent body. Volatile trace-element data exist for 58 H chondrite falls: the complete dataset includes Co, Rb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, and In (listed in increasing order of volatility) [2,3]. This dataset includes 13 H4, 32 H5, and 13 H6 chondrites, which cover the full range of shock facies from a through f. To examine the effect that shock has on volatile trace-element concentrations in H4-6 chondrites, we have compared data for the least-shocked samples (shock facies a-b) with the most shocked samples (shock facies c-f) using both univariate (Student's t-test) and multivariate techniques (linear discriminant analysis). The results demonstrate no reason to doubt the null hypothesis of no difference in volatile trace-element composition between shocked and unshocked H4-6 chondrites at any reasonable significance level. This situation contrasts sharply with the strong difference found between shocked and unshocked L chondrites [4]. The role of shock in establishing volatile trace- element contents in H and L chondrites clearly differs. Univariate comparisons between H4, H5, and H6 chondrites demonstrate that only Cs varies significantly with petrologic type (prob. > F 0.0006) with concentration decreasing monotonically with increasing petrographic type. Box- and-whisker plots of volatile trace-element contents reveal a general

  6. An Alteration Scale for CM Chondrites and Implications for Planetary Noble Gas Abundances

    Science.gov (United States)

    Browning, L. B.; McSween, H. Y., Jr.; Zolensky, M.

    1993-07-01

    Three progressive alteration parameters have been identified from the mineralogical and textural analyses of 7 CM chondritic falls. These indices predict the following order of progressive alteration [3]: Murchison (MC)Cochabamba (CC)< Murray (MY)< Mighei (MI) < Cold Bokkevelk (CB) < Nogoya (NG). We currently report an apparent relationship between advancing aqueous alteration and the bulk abundance of the planetary noble gases, Ar^36, Xe^84, and Kr^132. Two of the progressive alteration parameters monitor the volumetric production of CM phyllosilicates, which was estimated from the modal analysis of 1 to 3 thin sections from each of the analyzed falls. These are the percentages of phyllosilicates in chondrules and the volume of anhydrous matrix silicates, which increase and decease, respectively, with progressive alteration. The third alteration index, the mean Fe^3+/(2-Si) ratio in phyllosilicates, is a stoichiometric-based approximation that monitors variations in mineral composition during progressive alteration, and decreases with increasing alteration. Values of Fe^3+/(2-Si) were calculated from an average of microprobe analyses of matrix phyllosilicates in each meteorite based on a generalized phyllosilicate stoichiometry, [(Fe, Mg)(sub)3-x (Al,Fe^3+)(sub)x(Si(sub)(2-x)(Al,Fe^3+)(sub)x)O(sub)5(OH)(sub)4], which accommodates a continuous transition from cronstedtite to serpentine compositions. The bulk Ar^36 content of the 7 investigated samples decreases with increasing alteration as predicted by the alteration parameters, which suggests the possibility of degassing events. The same trend is observed for Kr^84 and Xe^132. The loss of noble gases in CM chondritic meteorites has previously been noted [1,5], and may be related to the open-system behavior that is predicted for other volatile components in CM chondrites, such as C1 [4], water [3], and methane [2]. Although high-temperature minerals are depleted in noble gases relative to the low- temperature

  7. A review and analysis of microwave absorption in polymer composites filled with carbonaceous particles

    Science.gov (United States)

    Qin, F.; Brosseau, C.

    2012-03-01

    Carbon (C) is a crucial material for many branches of modern technology. A growing number of demanding applications in electronics and telecommunications rely on the unique properties of C allotropes. The need for microwave absorbers and radar-absorbing materials is ever growing in military applications (reduction of radar signature of aircraft, ships, tanks, and targets) as well as in civilian applications (reduction of electromagnetic interference among components and circuits, reduction of the back-radiation of microstrip radiators). Whatever the application for which the absorber is intended, weight reduction and optimization of the operating bandwidth are two important issues. A composite absorber that uses carbonaceous particles in combination with a polymer matrix offers a large flexibility for design and properties control, as the composite can be tuned and optimized via changes in both the carbonaceous inclusions (C black, C nanotube, C fiber, graphene) and the embedding matrix (rubber, thermoplastic). This paper offers a perspective on the experimental efforts toward the development of microwave absorbers composed of carbonaceous inclusions in a polymer matrix. The absorption properties of such composites can be tailored through changes in geometry, composition, morphology, and volume fraction of the filler particles. Polymer composites filled with carbonaceous particles provide a versatile system to probe physical properties at the nanoscale of fundamental interest and of relevance to a wide range of potential applications that span radar absorption, electromagnetic protection from natural phenomena (lightning), shielding for particle accelerators in nuclear physics, nuclear electromagnetic pulse protection, electromagnetic compatibility for electronic devices, high-intensity radiated field protection, anechoic chambers, and human exposure mitigation. Carbonaceous particles are also relevant to future applications that require environmentally benign and

  8. Spectro-microscopic measurements of carbonaceous aerosol aging in Central California

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2013-04-01

    Full Text Available Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Carbonaceous Aerosols and Radiative Effects Study (CARES was designed to study carbonaceous aerosols in the natural environment of Central Valley, California, and learn more about their atmospheric formation and aging. This paper presents results from spectro-microscopic measurements of carbonaceous particles collected during CARES at the time of pollution accumulation event (27–29 June 2010, when in situ measurements indicated an increase in the organic carbon content of aerosols as the Sacramento urban plume aged. Computer controlled scanning electron microscopy coupled with an energy dispersive X-ray detector (CCSEM/EDX and scanning transmission X-ray microscopy coupled with near edge X-ray absorption spectroscopy (STXM/NEXAFS were used to probe the chemical composition and morphology of individual particles. It was found that the mass of organic carbon on individual particles increased through condensation of secondary organic aerosol. STXM/NEXAFS indicated that the number fraction of homogenous organic particles lacking inorganic inclusions (greater than ~50 nm diameter increased with plume age as did the organic mass per particle. Comparison of the CARES spectro-microscopic data set with a similar dataset obtained in Mexico City during the MILAGRO campaign showed that individual particles in Mexico City contained twice as much carbon as those sampled during CARES. The number fraction of soot particles at the Mexico City urban site (30% was larger than at the CARES urban site (10% and the most aged samples from CARES contained less carbon-carbon double bonds. Differences between carbonaceous particles in Mexico City and California result from different sources, photochemical conditions, gas phase reactants, and secondary organic aerosol precursors. The detailed results provided by these spectro

  9. Asteroid 6 Hebe: The probable parent body of the H-Type ordinary chondrites and the IIE iron meteorites

    Science.gov (United States)

    Gaffey, Michael J.; Gilbert, Sarah L.

    1998-11-01

    The S(IV)-type asteroid 6 Hebe is identified as the probable parent body of the H-type ordinary chondrites and of the IIE iron meteorites. The ordinary chondrites are the most common type of meteorites falling to Earth, but prior to the present study no large mainbelt source bodies have been confirmed. Hebe is located adjacent to both the (6 and 3:1 resonances, and has been previously suggested as a major potential source of the terrestrial meteorite flux. Hebe exhibits subtle rotational spectral variations indicating the presence of some compositional variations across its surface. The silicate portion of the surface assemblage of Hebe is consistent, both in overall average and in its range of variation, with the silicate components in the suite of H-type chondrites. The high albedo of Hebe rules out a lunar-style space weathering process to produce the weakened absorption features and reddish spectral slope in the S-type spectrum of Hebe. Linear unmixing models show that a typical nickel-iron metal spectrum is consistent with the component which modifies an H-chondrite spectrum to produce the S-type spectrum of Hebe. Based on the association between the H chondrites and the IIE iron meteorites, our model suggests that large impacts onto the relatively metal-rich H chondrite target produced melt bodies (sheets or pods) which differentiated to form thin, laterally extensive near-surface layers of NiFe metal. Fragments of the upper silicate portions of these melt bodies are apparently represented by some of the igneous inclusions in H-chondrite breccias. Alternately, masses of metal could have been deposited on the surface of Hebe by the impact of a core or core fragment from a differentiated parent body of H chondrite composition. Subsequent impacts preferentially eroded and depleted the overlying silicate and regolith components exposing and maintaining large masses of metal at the optical surface of Hebe. In this interpretation, the nonmagmatic IIE iron

  10. Refractory Inclusion Size Distribution and Fabric Measured in a Large Slab of the Allende CV3 Chondrite

    Science.gov (United States)

    Srinivasan, P.; Simon, Justin I.; Cuzzi, J. N.

    2013-01-01

    Aggregate textures of chondrites reflect accretion of early-formed particles in the solar nebula. Explanations for the size and density variations of particle populations found among chondrites are debated. Differences could have risen out of formation in different locations in the nebula, and/or they could have been caused by a sorting process [1]. Many ideas on the cause of chondrule sorting have been proposed; some including sorting by mass [2,3], by X-winds [4], turbulent concentration [5], and by photophoresis [6]. However, few similar studies have been conducted for Ca-, Al-rich inclusions (CAIs). These particles are known to have formed early, and their distribution could attest to the early stages of Solar System (ESS) history. Unfortunately, CAIs are not as common in chondrites as chondrules are, reducing the usefulness of studies restricted to a few thin sections. Furthermore, the largest sizes of CAIs are generally much larger than chondrules, and therefore rarely present in most studied chondrite thin sections. This study attempts to perform a more representative sampling of the CAI population in the Allende chondrite by investigating a two decimeter-sized slab.

  11. The Natural Thermoluminescence of Meteorites. Part 5; Ordinary Chondrites at the Allan Hills Ice Fields

    Science.gov (United States)

    Benoit, Paul H.; Sears, Hazel; Sears, Derek W. G.

    1993-01-01

    Natural thermoluminescence (TL) data have been obtained for 167 ordinary chondrites from the ice fields in the vicinity of the Allan Hills in Victoria Land, Antarctica, in order to investigate their thermal and radiation history, pairing, terrestrial age, and concentration mechanisms. Using fairly conservative criteria (including natural and induced TL, find location, and petrographic data), the 167 meteorite fragments are thought to represent a maximum of 129 separate meteorites. Natural TL values for meteorites from the Main ice field are fairly low (typically 5-30 krad, indicative of terrestrial ages of approx. 400 ka), while the Far western field shows a spread with many values 30-80 krad, suggestive of less then 150-ka terrestrial ages. There appear to be trends in TL levels within individual ice fields which are suggestive of directions of ice movement at these sites during the period of meteorite concentration. These directions seem to be confirmed by the orientations of elongation preserved in meteorite pairing groups. The proportion of meteorites with very low natural TL levels (less then 5 krad) at each field is comparable to that observed at the Lewis Cliff site and for modern non-Antarctic falls and is also similar to the fraction of small perihelia (less then 0.85 AU) orbits calculated from fireball and fall observations. Induced TL data for meteorites from the Allan Hills confirm trends observed for meteorites collected during the 1977/1978 and 1978/1979 field seasons which show that a select group of H chondrites from the Antarctic experienced a different extraterrestrial thermal history to that of non-Antarctic H chondrites.

  12. 53Mn-53Cr dating of fayalite formation in the CV3 chondrite Mokoia: evidence for asteroidal alteration.

    Science.gov (United States)

    Hutcheon, I D; Krot, A N; Keil, K; Phinney, D L; Scott, E R

    1998-12-01

    Fayalite grains in chondrules in the oxidized, aqueously altered CV3 chondrite Mokoia have large excesses of radiogenic chromium-53. These excesses indicate the in situ decay of short-lived manganese-53 (half-life = 3.7 million years) and define an initial 53Mn/55Mn ratio of 2.32 (+/-0.18) x 10(-6). This ratio is comparable to values for carbonates in CI and CM chondrites and for several classes of differentiated meteorites. Mokoia fayalites formed 7 to 16 million years after Allende calcium-aluminum-rich inclusions, during hydrothermal activity on a geologically active asteroid after chondritic components had ceased forming in the solar nebula. PMID:9836631

  13. High-pressure phases in shock-induced melt of the unique highly shocked LL6 chondrite Northwest Africa 757

    Science.gov (United States)

    Hu, Jinping; Sharp, Thomas G.

    2016-07-01

    Northwest Africa 757 is unique in the LL chondrite group because of its abundant shock-induced melt and high-pressure minerals. Olivine fragments entrained in the melt transform partially and completely into ringwoodite. Plagioclase and Ca-phosphate transform to maskelynite, lingunite, and tuite. Two distinct shock-melt crystallization assemblages were studied by FIB-TEM analysis. The first melt assemblage, which includes majoritic garnet, ringwoodite plus magnetite-magnesiowüstite, crystallized at pressures of 20-25 GPa. The other melt assemblage, which consists of clinopyroxene and wadsleyite, solidified at ~15 GPa, suggesting a second veining event under lower pressure conditions. These shock features are similar to those in S6 L chondrites and indicate that NWA 757 experienced an intense impact event, comparable to the impact event that disrupted the L chondrite parent body at 470 Ma.

  14. Exposure ages and radiogenic ages of ureilite(GRV 024516) and ordinary chondrite(GRV 024517) from Antarctica

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The GRV 024516 and GRV 024517 meteorite samples collected from Grove Montains,Antactica are ureilite and H5 ordinary chondrite,respectively.Based on the study of mineralogy-petrology ,the cosmic-ray exposure ages and gas retention ages of these two meteorites were determinated and calculated.Their cosmic-ray exposure ages are 33.3 Ma ,51.7 Ma,and gas retention ages are 1936.8 Ma and 3720 Ma,respectively.The ureilite contains diamond,graphite and amorphous C,which are mainly carrier of noble gases indicating obviously shock metamorphism effects,which induced 40Ar partial loss. The H5 chondrite indicates thermal metamorphism of parent body,its gas retention age fall the range between 3220 Ma and 4510 Ma of the least shocked H5 chondrites.

  15. The Amphibole-Bearing Chondrite Meteorite LAP04840: Metamorphism and `Tectonics' in a Hydrous Asteroid

    Science.gov (United States)

    Treiman, A. H.; McCanta, M. C.; Essene, E. J.

    2006-12-01

    LAP04840 is an R-chondrite found in Antarctica, and is unique among meteorites in containing abundant amphibole and biotite. Its chondrules (>500 μm diam) sit in a granoblastic matrix of grains ~20 μm across. Amphibole and biotite grains are anhedral to subhedral, to ~100 μm, and concentrated in chondrules. Commonly, they fit among the olivine and opx grains in regions that would (in anhydrous chondrules) have been occupied by cpx, mesostasis, or glass. Minerals are unzoned, and have constant compositions: olivine Fo62Fa38, Opx En60Wo01, plagioclase An07Ab90, magnesio-hornblende, (Ca1.52Na0.81K0.44) (Mg3.60Fe1.27Mn0.01Ti0.04Cr0.08) (Si6.95Al1.02Fe0.03) O22 (OH1.94?F0.05Cl0.01), sodian phlogopite (low Ti, F, Cl), magnetite (Mt63Chr28Sp05Usp04) and Fe-Ni sulfides. This assemblage is consistent with amphibolite facies equilibrium. Amph-plg thermometry (Holland &Blundy, 1994) gives 675°C, which is consistent with limits of ~600chondrite metamorphism are simple. After accretion in the early solar nebula, a chondritic asteroid is heated principally by decay of ^{26}Al (Ghosh et al., 2006) in a single prograde event. An asteroid in the inner belt (<~3AU) would accrete little ice, would be dry, and could be heated to (and beyond) 950°C (Hutchison, 2004). The R chondrites fit nicely here; all but LAP are dry and contain strongly metamorphosed clasts (but no melt rocks). Depending on bulk composition, heating can continue to and beyond the basalt solidus, with core formation and widespread melting and differentiation. An asteroid in the outer belt would accrete abundant ice, which would dilute ^{26}Al and sink much of its heat in melting and vaporization even cores of large asteroids (100+ km radius) would barely reach 675

  16. The evolution of enstatite and chondrules in unequilibrated enstatite chondrites: Evidence from iron-rich pyroxene

    Science.gov (United States)

    Weisberg, Michael K.; Prinz, Martin; Fogel, Robert A.

    1994-01-01

    FeO-rich (Fs(sub 6)-34) pyroxene lacking cathodoluminescence (CL), hereafter black pyroxene, is a major constituent of some of the chondrules and fragments in unequilibrated (type 3) enstatite chondrites (UECs). It contains structurally oriented zones of Cr-, Mn-, V-rich, FeO-poor enstatite with red CL, associated with mm-sized blebs of low-Ni, Fe-metal and, in some cases, silica. These occurrences represent clear evidence of pyroxene reduction. The black pyroxene is nearly always rimmed by minor element (Cr, Mn, V)-poor enstatite having a blue CL. More commonly, red and blue enstatites, unassociated with black pyroxene, occur as larger grains in chondrules and fragments, and these constitute the major silicate phases in UECs. The rare earth element (REE) abundance patterns of the black pyroxene are LREE-depleted. The blue enstatite rims, however, have a near-flat to LREE-enriched pattern, approx. 0.5-4x chondritic. The petrologic and trace element data indicate that the black pyroxene is from an earlier generation of chondrules that formed in a nebular region that was more oxidizing than that of the enstatite chondrites. Following solidification, these chondrules experienced a more reducing nebular environment and underwent reduction. Some, perhaps most, of the red enstatite that is common throughout the UECs may be the product of solid-state reduction of black pyroxene. The blue enstatite rims grew onto the surfaces of the black pyroxene and red enstatite as a result of condensation from a nebular gas. The evolutionary history of some of the enstatite and chondrules in enstatite chondrites can be expressed in a four-stage model that includes: Stage 1. Formation of chondrules in an oxidizing nebular environment. Stage 2. Solid-state reduction of the more oxidized chondrules and fragments to red enstatite in a more reducing nebular environment. Stage 3. Formation of blue enstatite rims on the black pyroxene as well as on the red enstatite. Stage 4. Reprocessing, by

  17. Striking Graphite Bearing Clasts Found in Two Ordinary Chondrite Samples; NWA6169 and NWA8330

    Science.gov (United States)

    Johnson, Jessica M.; Zolensky, Michael E.; Chan, Queenie; Kring, David A.

    2015-01-01

    Meteorites play an integral role in understanding the history of the solar system. Not only can they contain some of the oldest material found in the solar system they also can contain material that is unique. Many lithologies are only found as foreign clasts within distinctly different host meteorites. In this investigation two foreign clasts within the meteorites, NWA6169 and NWA8330 were studied. The purpose of this investigation was to examine the mineralogy and petrography of the clasts within the samples. From there an identification and possible origin were to be inferred. NWA6169 is an unclassified ordinary chondrite that has a presumed petrologic type of L3. NWA8330 is a classified ordinary chondrite that has a petrologic type of LL3. Both meteorites were found to contain clasts that were similar; both modally were comprised of about 5% acicular graphite. Through SEM and Raman Spectroscopy it was found that they contained olivine, pyroxene, plagioclase, Fe-Ni sulfides, graphite, and metals. They were found to portray an igneous texture with relationships that suggest concurrent growth. Analytical microprobe results for NWA6169 revealed mineral compositions of Fa31-34, Fs23-83, and Ab7-85. For NWA8330 these were Fa28-32, Fs10-24, and Ab4-83. Only one similar material has been reported, in the L3 chondrite Krymka (Semenenko & Girich, 1995). The clast they described exhibited similar mineralogies including the unusual graphite. Krymka data displayed compositional values of Fa28.5-35.0 and Fs9-25.9. These ranges are fairly similar to that of NWA6169 and NWA8330. These samples may all be melt clasts, probably of impact origin. Two possibilities are (1) impact of a C-type asteroid onto the L chondrite parent asteroid, and (2) a piece of proto-earth ejected from the moon-forming collision event. These possibilities present abundant questions, and can be tested. The measurement of oxygen isotope compositions from the clasts should reveal the original source of the

  18. 40Ar/39Ar age and thermal history of the Kirin chondrite

    International Nuclear Information System (INIS)

    The Kirin meteorite, a large (> 2800 kg) H5 chondrite, fell in Kirin Province, China in 1976. A sample from each of the two largest fragments (K-1. K-2) yield 40Ar/39Ar total fusion ages of 3.63 +- 0.02 b.y. and 2.78 +- 0.02 b.y. respectively. 40Ar/40Ar age spectra show typical diffusional argon loss profiles. Maximum apparent ages of 4.36 b.y. (K-1) and approx. 4.0 b.y. (K-2) are interpreted as possible minimum estimates for the age of crystallization of the parent body. (orig./ME)

  19. The magnetic effects of brecciation and shock in meteorites. I - The LL-chondrites

    Science.gov (United States)

    Brecher, A.; Stein, J.; Fuhrman, M.

    1977-01-01

    The magnetic behavior of eight LL chondrites is analyzed in detail, and some implications for their modes of formation and evolutionary history are examined. Petrographic features of the specimens are described, and their initial magnetic characteristics are discussed. The demagnetization behavior of the initial magnetization is investigated along with the saturation remanence behavior and paleomagnetic-field intensities. The results indicate that a magnetic field of 0.01 to 0.1 Oe may have been present during postimpact cooling and that severe shock metamorphism may have given rise to the observed magnetic moments and behavior, even in the absence of ambient magnetic fields.

  20. The Gao-Guenie impact melt breccia—Sampling a rapidly cooled impact melt dike on an H chondrite asteroid?

    Science.gov (United States)

    Schmieder, Martin; Kring, David A.; Swindle, Timothy D.; Bond, Jade C.; Moore, Carleton B.

    2016-04-01

    The Gao-Guenie H5 chondrite that fell on Burkina Faso (March 1960) has portions that were impact-melted on an H chondrite asteroid at ~300 Ma and, through later impact events in space, sent into an Earth-crossing orbit. This article presents a petrographic and electron microprobe analysis of a representative sample of the Gao-Guenie impact melt breccia consisting of a chondritic clast domain, quenched melt in contact with chondritic clasts, and an igneous-textured impact melt domain. Olivine is predominantly Fo80-82. The clast domain contains low-Ca pyroxene. Impact melt-grown pyroxene is commonly zoned from low-Ca pyroxene in cores to pigeonite and augite in rims. Metal-troilite orbs in the impact melt domain measure up to ~2 mm across. The cores of metal orbs in the impact melt domain contain ~7.9 wt% of Ni and are typically surrounded by taenite and Ni-rich troilite. The metallography of metal-troilite droplets suggest a stage I cooling rate of order 10 °C s-1 for the superheated impact melt. The subsolidus stage II cooling rate for the impact melt breccia could not be determined directly, but was presumably fast. An analogy between the Ni rim gradients in metal of the Gao-Guenie impact melt breccia and the impact-melted H6 chondrite Orvinio suggests similar cooling rates, probably on the order of ~5000-40,000 °C yr-1. A simple model of conductive heat transfer shows that the Gao-Guenie impact melt breccia may have formed in a melt injection dike ~0.5-5 m in width, generated during a sizeable impact event on the H chondrite parent asteroid.

  1. The Gao-Guenie impact melt breccia—Sampling a rapidly cooled impact melt dike on an H chondrite asteroid?

    Science.gov (United States)

    Schmieder, Martin; Kring, David A.; Swindle, Timothy D.; Bond, Jade C.; Moore, Carleton B.

    2016-06-01

    The Gao-Guenie H5 chondrite that fell on Burkina Faso (March 1960) has portions that were impact-melted on an H chondrite asteroid at ~300 Ma and, through later impact events in space, sent into an Earth-crossing orbit. This article presents a petrographic and electron microprobe analysis of a representative sample of the Gao-Guenie impact melt breccia consisting of a chondritic clast domain, quenched melt in contact with chondritic clasts, and an igneous-textured impact melt domain. Olivine is predominantly Fo80-82. The clast domain contains low-Ca pyroxene. Impact melt-grown pyroxene is commonly zoned from low-Ca pyroxene in cores to pigeonite and augite in rims. Metal-troilite orbs in the impact melt domain measure up to ~2 mm across. The cores of metal orbs in the impact melt domain contain ~7.9 wt% of Ni and are typically surrounded by taenite and Ni-rich troilite. The metallography of metal-troilite droplets suggest a stage I cooling rate of order 10 °C s-1 for the superheated impact melt. The subsolidus stage II cooling rate for the impact melt breccia could not be determined directly, but was presumably fast. An analogy between the Ni rim gradients in metal of the Gao-Guenie impact melt breccia and the impact-melted H6 chondrite Orvinio suggests similar cooling rates, probably on the order of ~5000-40,000 °C yr-1. A simple model of conductive heat transfer shows that the Gao-Guenie impact melt breccia may have formed in a melt injection dike ~0.5-5 m in width, generated during a sizeable impact event on the H chondrite parent asteroid.

  2. The origin and hydrothermal mobilization of carbonaceous matter associated with Paleoproterozoic orogenic-type gold deposits of West Africa

    Czech Academy of Sciences Publication Activity Database

    Kříbek, B.; Sýkorová, Ivana; Machovič, V.; Knésl, I.; Laufek, F.; Zachariáš, J.

    2015-01-01

    Roč. 270, November 01 (2015), s. 300-317. ISSN 0301-9268 Institutional support: RVO:67985891 Keywords : carbonaceous matter * gold deposits * graphite Subject RIV: DB - Geology ; Mineralogy Impact factor: 5.664, year: 2014

  3. The Biological Potency Of Carbonaceous Nanoparticles Is Associated With The State Of Oxidation Of Surface Carbon Atoms

    Science.gov (United States)

    Epidemiological studies have shown that exposure to ambient particulate matter (PM) is associated with excess morbidity and mortality. An important component of PM consists of inorganic and organic compounds adsorbed onto a carbonaceous particle core. Toxicological studies indica...

  4. Uranium-lead Isotope Evidence in the Shelyabinsk LL5 Chondrite Meteorite for Ancient and Recent Thermal Events

    Science.gov (United States)

    Lapen, T. J.; Kring, D. A.; Zolensky, M. E.; Andreasen, R.; Righter, M.; Swindle, T. D.; Beard, S. P.; Swindle, T. D.

    2014-01-01

    The impact histories on chondrite parent bodies can be deduced from thermochronologic analyses of materials and isotope systems with distinct apparent closure temperatures. It is especially critical to better understand the geological histories and physical properties of potenally hazardous near-Earth asteroids. Chelyabinsk is an LL5 chondrite meteorite that was dispersed over a wide area tens of kilometers south of the town of Chelyabinsk, Russia by an explosion at an altitude of 27 km at 3:22 UT on 15 Feb 2013 [1,2]. The explosion resulted in significant damage to surrounding areas and over 1500 injuries along with meteorite fragments being spread over a wide area [1].

  5. Oxygen isotope and petrological study of silicate inclusions in IIE iron meteorites and their relationship with H chondrites

    Science.gov (United States)

    McDermott, Kathryn H.; Greenwood, Richard C.; Scott, Edward R. D.; Franchi, Ian A.; Anand, Mahesh

    2016-01-01

    The origin of silicate-bearing irons, especially those in groups IAB, IIICD, and IIE, is poorly understood as silicate should have separated rapidly from molten metal. Here we report the results of high precision oxygen isotope analysis of silicate inclusions in eleven group IIE meteorites and a petrological study of silicate inclusions in ten IIE irons including those in Garhi Yasin and Tarahumara, which have not been described in detail before. Oxygen isotopes have also been analysed in 20 H chondrites to investigate their possible relationship with the IIE irons. Based on petrographic observations and mineral analysis, the silicate-bearing IIE meteorites have been divided into four types according to the nature of their silicate inclusions: (1) primitive chondritic, (2) evolved chondritic, (3) differentiated with >10 vol.% orthopyroxene, and (4) differentiated with IIE meteorite tend to show relatively limited Δ17O variation, a wide range of values is seen in the dataset as a whole. Group IIE irons with differentiated silicates, with the exception of Colomera, have a range of mean Δ17O values that is essentially identical to those of the H4-6 chondrites: 0.60-0.77‰ and 0.61-0.76‰, respectively. Colomera inclusions, which are differentiated with IIE iron. However, in view of the textural similarities to other IIE inclusions, a separate source for Colomera is deemed unlikely. Three IIE irons with primitive chondritic inclusions, Garhi Yasin, Netschaëvo, and Techado, have relatively low mean Δ17O values of 0.56-0.57‰ as well as relatively reduced silicates with Fa15-17 olivine, which have been called HH chondrites. Given the significant overlap in their oxygen isotope compositions, a genetic relationship between IIE irons and H chondrites is supported by our new data. However, derivation of both groups from one parent body seems unlikely. Instead, both groups probably sampled similar precursor materials and accreted at a similar nebular location. Our data

  6. Outgassing of Ordinary Chondritic Material and Some of its Implications for the Chemistry of Asteroids, Planets, and Satellites

    OpenAIRE

    Schaefer, Laura; Fegley, Jr, Bruce

    2006-01-01

    We used chemical equilibrium calculations to model thermal outgassing of ordinary chondritic material as a function of temperature, pressure, and bulk compositions and use our results to discuss outgassing on asteroids and the early Earth. The calculations include ~1,000 solids and gases of the elements Al, C, Ca, Cl, Co, Cr, F, Fe, H, K, Mg, Mn, N, Na, Ni, O, P, S, Si, and Ti. The major outgassed volatiles from ordinary chondritic material are CH4, H2, H2O, N2, and NH3(the latter at conditio...

  7. Formation of PAHs and Carbonaceous Solids in Gas-Phase Condensation Experiments

    CERN Document Server

    Jäger, C; Jansa, I Llamas; Henning, T; Huisken, F

    2009-01-01

    Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs), that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile 3-5 ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot AGB stars or W...

  8. Sustainable approach toward synthesis of green functional carbonaceous 3-D micro/nanostructures from biomass

    Science.gov (United States)

    Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, Krishnan

    2013-08-01

    This study proposes a novel technique to synthesize functional carbonaceous three-dimensional (3-D) micro/nanocompounds from agricultural by-products using femtosecond laser irradiation. Biowastes of rice husk and wheat straw are value-engineered to carbonaceous structures in a single-step process under ambient conditions. Our results demonstrate that by controlling the laser fluence, structures with a variety of different morphologies from nanostructures to microstructures can be achieved. Also, the results indicate that altering the laser processing parameters influences the chemical composition of the synthesized structures. This sustainable approach presents an important step towards synthesizing 3-D micro/nanofibrous compounds from biowaste materials. These structures, as-synthesized or as nanocomposite fillers, can have practical uses in electronic, sensing, biological, and environmental applications.

  9. Adsorption and Desorption of Carbon Dioxide and Water Mixtures on Synthetic Hydrophobic Carbonaceous Adsorbents

    Science.gov (United States)

    Finn, John E.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Several synthetic carbonaceous adsorbents produced through pyrolysis of polymeric materials are available commercially. Some appear to have advantages over activated carbon for certain adsorption applications. In particular, they can have tailored hydrophobicities that are significantly greater than that of activated carbon, while moderately high surfaces areas are retained. These sorbents are being investigated for possible use in removing trace contaminants and excess carbon dioxide from air in closed habitats, plant growth chambers, and other applications involving purification of humid gas streams. We have analyzed the characteristics of a few of these adsorbents through adsorption and desorption experiments and standard characterization techniques. This paper presents pure and multicomponent adsorption data collected for carbon dioxide and water on two synthetic carbonaceous adsorbents having different hydrophobicities and capillary condensation characteristics. The observations are interpreted through consideration of the pore structure and surface chemistry of the solids and interactions between adsorbed carbon dioxide, water, and the solvent gas.

  10. Aqueous accelerated solvent extraction of native polycyclic aromatic hydrocarbons (PAHs) from carbonaceous river floodplain soils

    International Nuclear Information System (INIS)

    In this study, three river floodplain soils with different compositions of carbonaceous materials and a reference coal sample were extracted with water using the accelerated solvent extraction (ASE) method. The desorption enthalpy values for 2-ring PAHs were highest in the coal sample, with values in the soil samples decreasing with decrease in coal content. The values for the higher condensed PAHs showed that the highest desorption enthalpies were from the samples with the largest amount of coal-derived particles. Elevated desorption enthalpies indicated a strong bonding between PAHs and geosorbents. Moreover, with the application of ASE this study was able to conclude that the PAHs in the samples were preferentially adsorbed to carbonaceous materials with high surface areas. - Native PAHs in river floodplain soils were preferentially bound to coal and coal-derived particles with a strong sorption affinity.

  11. Noble gas trapping and fractionation during synthesis of carbonaceous matter. [in meteorites

    Science.gov (United States)

    Frick, U.; Mack, R.; Chang, S.

    1979-01-01

    An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

  12. Interpretation of measurments of carbonaceous deposition on irradiated CAGR fuel pins

    International Nuclear Information System (INIS)

    Measurements of carbonaceous deposition on irradiated fuel from almost the whole initial charges of the Advanced Gas-cooled reactors (AGRs) at Hinkley Point 'B' and Hunterston 'B' are reviewed. The source of carbonaceous deposition on fuel pins is thought to be oil leakage into the core from the gas circulators, except for the recent occurrence of apparently coolant-derived deposition in Hinkley R3. The implications on the heat-transfer of the observed levels of deposition are discussed, as are the effects of clad surface and possible surface treatments. Effects of irradiation time and coolant composition are assessed and it is shown that operation to the target discharge irradiation of 24 GWd/te will not lead to unacceptable levels of deposition as long as methane and carbon monoxide concentrations are maintained within limits that avoid deposition from these components. (author)

  13. Aqueous accelerated solvent extraction of native polycyclic aromatic hydrocarbons (PAHs) from carbonaceous river floodplain soils.

    Science.gov (United States)

    Yang, Yi; Hofmann, Thilo

    2009-10-01

    In this study, three river floodplain soils with different compositions of carbonaceous materials and a reference coal sample were extracted with water using the accelerated solvent extraction (ASE) method. The desorption enthalpy values for 2-ring PAHs were highest in the coal sample, with values in the soil samples decreasing with decrease in coal content. The values for the higher condensed PAHs showed that the highest desorption enthalpies were from the samples with the largest amount of coal-derived particles. Elevated desorption enthalpies indicated a strong bonding between PAHs and geosorbents. Moreover, with the application of ASE this study was able to conclude that the PAHs in the samples were preferentially adsorbed to carbonaceous materials with high surface areas. PMID:19524343

  14. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    OpenAIRE

    Constantin Apetrei; Maria Luz Rodriguez-Mendez; Jose Antonio De Saja; Irina Mirela Apetrei

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, L-ascorbic acid and L-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, wh...

  15. State of the art on reactor designs for solar gasification of carbonaceous feedstock

    DEFF Research Database (Denmark)

    Puig Arnavat, Maria; Tora, E.A.; Bruno, J.C.;

    2013-01-01

    to produce high quality synthesis gas with a higher output per unit of feedstock and that allows for the chemical storage of solar energy in the form of a readily transportable fuel, among other advantages. The present paper describes the latest advances in solar thermochemical reactors for...... gasification of carbonaceous feedstocks. This work is categorized in this paper into patents and research/journal papers. © 2013 Elsevier Ltd....

  16. Carbonaceous emissions reflected in deposits on building stones: Case study in Prague Castle

    Czech Academy of Sciences Publication Activity Database

    Sýkorová, Ivana; Havelcová, Martina; Zeman, Antonín; Trejtnarová, Hana; Matysová, Petra; Šulc, Alexandr

    Pittsburgh : University of Pittsburgh, 2010, s. 1-4. ISBN 1-890977-27-6. [Annual International Pittsburgh Coal Conference /27./. Istanbul (TR), 11.10.2010-14.10.2010] R&D Projects: GA AV ČR IAA300460804 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z20710524 Keywords : historical building materials * air pollution * Carbonaceous matter Subject RIV: DD - Geochemistry

  17. Spheroidal carbonaceous particles are a defining stratigraphic marker for the Anthropocene

    OpenAIRE

    Swindles, GT; Watson, E.; Turner, TE; Galloway, JM; Hadlari, T; Wheeler, J; Bacon, KL

    2015-01-01

    There has been recent debate over stratigraphic markers used to demarcate the Anthropocene from the Holocene Epoch. However, many of the proposed markers are found only in limited areas of the world or do not reflect human impacts on the environment. Here we show that spheroidal carbonaceous particles (SCPs), a distinct form of black carbon produced from burning fossil fuels in energy production and heavy industry, provide unambiguous stratigraphic markers of the human activities that have ra...

  18. Fermentation, gasification and pyrolysis of carbonaceous residues towards usage in fuel cells

    International Nuclear Information System (INIS)

    In this paper, the technologies of fermentation, gasification and pyrolysis of carbonaceous residues for the production of biohydrogen and other gaseous, liquid or solid fuels, are analysed. The energetic, economic and environmental advantages of linking these energy areas with the fuel cell engines are stressed. In addition, the current status of fuel cell technologies, namely their historic trends, basic electrode mechanisms, cell types, market drivers and leading issues, are reviewed

  19. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996–2010

    OpenAIRE

    Lu, Z.; Q. Zhang; D. G. Streets

    2011-01-01

    China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2) and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC) emissions from these two countries for the period 1996–2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission ...

  20. Annual variations of carbonaceous PM2.5 in Malaysia: Influence by Indonesian peatland fires

    OpenAIRE

    Fujii, Y.; S. Tohno; Amil, N.; M. T. Latif; Oda, M.; Matsumoto, J.; A. Mizohata

    2015-01-01

    In this study, we quantified carbonaceous PM2.5 in Malaysia through annual observations of PM2.5, focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and c...

  1. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Jeffrey [Univ. of Arkansas, Little Rock, AR (United States)

    2012-12-12

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  2. Implementing a new EPR lineshape parameter for organic radicals in carbonaceous matter

    OpenAIRE

    Bourbin, Mathilde; Du, Yann Le; Binet, Laurent; Gourier, Didier

    2013-01-01

    Background Electron Paramagnetic Resonance (EPR) is a non-destructive, non-invasive technique useful for the characterization of organic moieties in primitive carbonaceous matter related to the origin of life. The classical EPR parameters are the peak-to-peak amplitude, the linewidth and the g factor; however, such parameters turn out not to suffice to fully determine a single EPR line. Results In this paper, we give the definition and practical implementation of a new EPR parameter based on ...

  3. Origin of fine carbonaceous particulate matter in the Western Mediterranean Basin: fossil versus modern sources

    Science.gov (United States)

    Cruz Minguillón, María.; Perron, Nolwenn; Querol, Xavier; Szidat, Sönke; Fahrni, Simon; Wacker, Lukas; Reche, Cristina; Cusack, Michael; Baltensperger, Urs; Prévôt, André S. H.

    2010-05-01

    The present work was carried out in the frame of the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean). The objective of this campaign is to study the aerosol pollution episodes occurring at regional scale during winter and summer in the Western Mediterranean Basin. As part of this campaign, this work focuses on identifying the origin of fine carbonaceous aerosols. To this end, fine particulate matter (PM1) samples were collected during two different seasons (February-March and July 2009) at two sites: an urban site (Barcelona, NE Spain) and a rural European Supersite for Atmospheric Aerosol Research (Montseny, NE Spain). Subsequently, 14C analyses were carried out on these samples, both in the elemental carbon (EC) fraction and the organic carbon (OC) fraction, in order to distinguish between modern carbonaceous sources (biogenic emissions and biomass burning emissions) and fossil carbonaceous sources (mainly road traffic). Preliminary results from the winter period show that 40% of the OC at Barcelona has a fossil origin whereas at Montseny this percentage is 30%. These values can be considered as unexpected given the nature of the sites. Nevertheless, the absolute concentrations of fossil OC at Barcelona and Montseny differ by a factor of 2 (the first being higher), since the total OC at Montseny is lower than at Barcelona. Further evaluation of results and comparison with other measurements carried out during the campaign are required to better evaluate the origin of the fine carbonaceous matter in the Western Mediterranean Basin. Acknowledgements: Spanish Ministry of Education and Science, for a Postdoctoral Grant awarded to M.C. Minguillón in the frame of Programa Nacional de Movilidad de Recursos Humanos del Plan nacional de I-D+I 2008-2011. Spanish Ministry of Education and Science, for the Acción Complementaria DAURE CGL2007-30502-E/CLI.

  4. Carbonaceous species and humic like substances (HULIS) in Arctic snowpack during OASIS field campaign in Barrow

    OpenAIRE

    Voisin, Didier; Jaffrezo, Jean-Luc; Houdier, Stephan; Barret, Manuel; Cozic, Julie; King, Martin D.; France, James L.; Reay, Holly J.; Grannas, Amanda; Kos, Gregor; Ariya, Parisa A.; Beine, Harry J.; Domine, Florent

    2012-01-01

    Snowpacks contain many carbonaceous species that can potentially impact on snow albedo and arctic atmospheric chemistry. During the OASIS field campaign, in March and April 2009, Elemental Carbon (EC), Water insoluble Organic Carbon (WinOC) and Dissolved Organic Carbon (DOC) were investigated in various types of snow: precipitating snows, remobilized snows, wind slabs and depth hoars. EC was found to represent less than 5% of the Total Carbon Content (TCC = EC + WinOC + DOC), whereas WinOC wa...

  5. Bulk micromachining of silicon using electron-beam-induced carbonaceous nanomasking

    International Nuclear Information System (INIS)

    This paper reports on an alternative nanolithographic technique for bulk micromachining of silicon. We show how to selectively etch Si(110) in aqueous KOH solutions using electron-beam-induced nanomasking. Already nanometre thin carbonaceous films can completely suppress the wet anisotropic chemical etching of Si performed in alkaline solution (10 wt% KOH+5 wt% isopropanol). It is shown that under optimized conditions, this approach can be exploited for the fabrication of three-dimensional micro- and nanostructures

  6. Bulk micromachining of silicon using electron-beam-induced carbonaceous nanomasking

    Energy Technology Data Exchange (ETDEWEB)

    Djenizian, T [Laboratoire MADIREL (UMR 6121), Electrochemistry of Materials Group, Universite de Provence-CNRS Centre Saint Jerome, F-13397 Marseille Cedex 20 (France); Salhi, B [Institut de Recherche Interdisciplinaire (IRI), Avenue Poincare BP 60069, 59652 Villeneuve d' Ascq (France); Boukherroub, R [Institut de Recherche Interdisciplinaire (IRI), Avenue Poincare BP 60069, 59652 Villeneuve d' Ascq (France); Schmuki, P [Department of Materials Science, University of Erlangen-Nuremberg, WW4-LKO, Martensstrasse 7, D-91058 Erlangen (Germany)

    2006-11-14

    This paper reports on an alternative nanolithographic technique for bulk micromachining of silicon. We show how to selectively etch Si(110) in aqueous KOH solutions using electron-beam-induced nanomasking. Already nanometre thin carbonaceous films can completely suppress the wet anisotropic chemical etching of Si performed in alkaline solution (10 wt% KOH+5 wt% isopropanol). It is shown that under optimized conditions, this approach can be exploited for the fabrication of three-dimensional micro- and nanostructures.

  7. Key parameters when developing carbonaceous materials for catalytic wet peroxide oxidation

    OpenAIRE

    Ribeiro, Rui; Silva, Adrián; Pastrana-Martínez, Luisa; Figueiredo, José; Faria, Joaquim; Gomes, Helder

    2014-01-01

    Catalytic wet peroxide oxidation (CWPO) is an advanced oxidation process, operated using simple equipment and mild operating conditians, in which highly oxidizing hydraxyl radicaIs (HO') are generated fram the catalytic decompasition af hydrogen peroxide (H,O,) [L 2). Sinee the report of Lüeking el ai. in 1998 [3], the develapment af suitab-Ie -carbonaceous materials (without any added metal phase) for CWPO has been intensively explored [4). lhe influenee of struetUfal and surr...

  8. Raman Spectroscopy of Carbonaceous Materials geothermometry: a reliable method to investigate thermal history of foreland basins.

    OpenAIRE

    Lahfid, Abdeltif; Lacroix, Brice; Hoareau, Guilhem; Delchini, Sylvain; Bourrat, Xavier

    2014-01-01

    To investigate the thermal evolu-tion of foreland basins, many classical methods includ-ing clay mineralogy, vitrinite reflectance, fluid inclu-sions and illite cristalinity are used. These methods are probably not perfectly reliable taken individually, but provides a robust estimate when they give a coherent results. Raman Spectroscopy of Carbonaceous Materials (RSCM) could be an alternative method to constrain paleotempeartures of rocks. This method has been calibrated firstly in the range ...

  9. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    International Nuclear Information System (INIS)

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  10. Ore-forming environment and ore-forming system of carbonaceous-siliceous-pelitic rock type uranium deposit in China

    International Nuclear Information System (INIS)

    It is proposed that there are four types of ore-forming systems about carbonaceous-siliceous-pelitic rock type uranium deposit in China based on systematic study on structural environment and distribution regularity of uraniferous construction of marine carbonaceous-siliceous-pelitic rock in China: continental margin rift valley ore-forming systems, continental margin rifting deep fracture zone ore-forming systems, landmass boundary borderland basin ore-forming systems and epicontinental mobile belt downfaulted aulacogen ore-forming systems. It is propounded definitely that it is controlled by margin rift valley ore-forming systems and continental margin rifting deep fracture zone ore-forming systems for large-scale uranium mineralization of carbonaceous-siliceous-pelitic rock type uranium deposit in China, which is also controlled by uraniferous marine carbonaceous-siliceous-pelitic rock construction made up of silicalite, siliceous phosphorite and carbonaceous-siliceous-pelitic rock, which settled down accompany with submarine backwash and sub marine volcanic eruption in margin rift valley and continental margin rifting mineralizing environment. Continental mar gin rift valley and continental margin rifting thermal sedimentation or exhalation sedimentation is the mechanism of forming large-scale uraniferous marine carbonaceous-siliceous-pelitic rock construction Early Palaeozoic Era in China or large-scale uranium-polymetallic mineralization. (authors)

  11. Anticorrosion properties of tin oxide coatings for carbonaceous bipolar plates of proton exchange membrane fuel cells

    Science.gov (United States)

    Kinumoto, Taro; Nagano, Keita; Yamamoto, Yuji; Tsumura, Tomoki; Toyoda, Masahiro

    2014-03-01

    An anticorrosive surface treatment of a carbonaceous bipolar plate used in proton exchange membrane fuel cells (PEMFCs) was demonstrated by addition of a tin oxide surface coating by liquid phase deposition (LPD), and its effectiveness toward corrosion prevention was determined. The tin oxide coating was deposited by immersion in tin fluoride and boric acid solutions, without any observable decrease in the bipolar plate electrical conductivity. Anticorrosion properties of a flat carbonaceous bipolar plate were investigated in an aqueous HClO4 electrolyte solution (10 μmol dm-3) at 80 °C. CO2 release due to corrosion was significant for the bare specimen above 1.3 V, whereas no CO2 release was noted for the tin-oxide-coated specimen, even approaching 1.5 V. Moreover, minimal changes in contact angle against a water droplet before and after treatment indicated suppressed corrosion of the surface-coated specimen. Anticorrosion properties were also confirmed for a model bipolar plate having four gas flow channels. The tin oxide layer remained on the channel surfaces (inner walls, corners and intersections) after durability tests. Based on these results, tin-oxide-based surface coatings fabricated by LPD show promise as an anticorrosion technique for carbonaceous bipolar plates for PEMFCs.

  12. Low extraction recovery of fullerene from carbonaceous geological materials spiked with C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Jehlicka, J.; Frank, O.; Hamplova, V.; Pokorna, Z.; Juha, L.; Bohacek, Z.; Weishauptova, Z. [Charles University, Prague (Czech Republic). Inst. for Geochemical Mineral & Mineral Resources

    2005-08-01

    Soxhlet extraction, sonication, and ultracritical extraction were tested with respect to their capacity to extract fullerenes from natural carbonaceous materials. Toluene solutions with various contents of synthetic C{sub 60} were added to powdered graphite, shungite, bituminous coal, and quartz, with final C{sub 60} concentration 0.1-100 ppm. The C{sub 60}-doped materials were leached in three kinds of extraction apparatus. High-performance liquid chromatography (HPLC) was used to analyse the fullerene content in the obtained toluene extracts. Surprisingly low yields of the C{sub 60} extraction (most of them well below 5%) were determined for all the carbonaceous matrices and all the extraction techniques employed in the fullerene isolation. This finding has serious consequences for better understanding of the reported fullerene occurrence in the geological environment, because a greatly limited extraction yield can be responsible for some negative results of fullerene analyses in various geological samples. Both fullerene stability in solvents and fullerene interaction with the surfaces of geological carbonaceous matrices are discussed to explain the obtained results.

  13. Adsorption of perfluoroalkyl acids by carbonaceous adsorbents: Effect of carbon surface chemistry

    International Nuclear Information System (INIS)

    Adsorption by carbonaceous sorbents is among the most feasible processes to remove perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) from drinking and ground waters. However, carbon surface chemistry, which has long been recognized essential for dictating performance of such sorbents, has never been considered for PFOS and PFOA adsorption. Thus, the role of surface chemistry was systematically investigated using sorbents with a wide range in precursor material, pore structure, and surface chemistry. Sorbent surface chemistry overwhelmed physical properties in controlling the extent of uptake. The adsorption affinity was positively correlated carbon surface basicity, suggesting that high acid neutralizing or anion exchange capacity was critical for substantial uptake of PFOS and PFOA. Carbon polarity or hydrophobicity had insignificant impact on the extent of adsorption. Synthetic polymer-based Ambersorb and activated carbon fibers were more effective than activated carbon made of natural materials in removing PFOS and PFOA from aqueous solutions. - Highlights: • Adsorption of PFOS and PFOA by ten carbonaceous adsorbents were compared. • Surface chemistry of the adsorbents controlled adsorption affinity. • Carbon surface basicity was positively correlated with the extent of PFOS and PFOA uptake. • Carbon polarity or hydrophobicity was not correlated with adsorption affinity. • Synthetic polymer-based adsorbents were more effective in removing PFOS and PFOA. - Carbon surface basicity is the primary factor that influences adsorption affinity of the carbonaceous sorbents for perfluorooctane sulfonic and carboxylic acids

  14. Atmospheric carbonaceous aerosols from Indo-Gangetic Plain and Central Himalaya: impact of anthropogenic sources.

    Science.gov (United States)

    Ram, Kirpa; Sarin, M M

    2015-01-15

    In the present-day scenario of growing anthropogenic activities, carbonaceous aerosols contribute significantly (∼20-70%) to the total atmospheric particulate matter mass and, thus, have immense potential to influence the Earth's radiation budget and climate on a regional to global scale. In addition, formation of secondary organic aerosols is being increasingly recognized as an important process in contributing to the air-pollution and poor visibility over urban regions. It is, thus, essential to study atmospheric concentrations of carbonaceous species (EC, OC and WSOC), their mixing state and absorption properties on a regional scale. This paper presents the comprehensive data on emission sources, chemical characteristics and optical properties of carbonaceous aerosols from selected urban sites in the Indo-Gangetic Plain (IGP) and from a high-altitude location in the central Himalaya. The mass concentrations of OC, EC and WSOC exhibit large spatio-temporal variability in the IGP. This is attributed to seasonally varying emissions from post-harvest agricultural-waste burning, their source strength, boundary layer dynamics and secondary aerosol formation. The high concentrations of OC and SO4(2-), and their characteristic high mass scattering efficiency, contribute significantly to the aerosol optical depth and scattering coefficient. This has implications to the assessment of single scattering albedo and aerosol radiative forcing on a regional scale. PMID:25199599

  15. Chondritic-like xenon trapped in Archean rocks: A possible signature of the ancient atmosphere

    Science.gov (United States)

    Pujol, Magali; Marty, Bernard; Burgess, Ray

    2011-08-01

    Ancient sedimentary rocks may have retained a record of the past atmospheric composition. We present evidence for the geological preservation of remnants of the Archean atmosphere. Hydrothermal quartz containing fluid inclusions from a core drilled in 3.5 Ga-old terrains at North Pole, (Western Australia), has a Ar-Ar plateau age of 3.0 ± 0.2 Ga. An Archean age is confirmed independently by 130Ba- 130Xe dating of fluid inclusions. Xenon trapped in the present sample and in 3.5 Ga-old barite from the same locality (Pujol et al., 2009; Srinivasan, 1976) presents an isotopic composition intermediate between the atmospheric composition and that of chondritic, or solar, xenon. In contrast, the stable isotopes of neon and krypton are isotopically atmospheric. This observation suggests that the well known but unexplained enrichment of heavy Xe isotopes in the atmosphere relative to cosmochemical (chondritic or solar) end-members was progressive, and not complete ≥ 3 Ga ago. This Xe isotopic fractionation might have taken place during prolongated irradiation of the atmosphere by the ancient Sun.

  16. Magnetic hysteresis in natural materials. [chondrites, lunar samples and terrestrial rocks

    Science.gov (United States)

    Wasilewski, P. J.

    1973-01-01

    Magnetic hysteresis loops and the derived hysteresis ratios R sub H and R sub I are used to classify the various natural dilute magnetic materials. R sub I is the ratio of saturation isothermal remanence (I sub R) to saturation (I sub S) magnetization, and R sub H is the ratio of remanent coercive force (H sub R) to coercive force (H sub C). The R sub H and R sub I values depend on grain size, the characteristics of separate size modes in mixtures of grains of high and low coercivity, and the packing characteristics. Both R sub H and R sub I are affected by thermochemical alterations of the ferromagnetic fraction. Hysteresis loop constriction is observed in lunar samples, chondrite meteorites, and thermochemically altered basaltic rocks, and is due to mixtures of components of high and low coercivity. Discrete ranges of R sub H and R sub I for terrestrial and lunar samples and for chondrite meteorites provide for a classification of these natural materials based on their hysteresis properties.

  17. Mineral and chemical composition of the Jezersko meteorite—A new chondrite from Slovenia

    Science.gov (United States)

    Miler, Miloš; Ambrožič, Bojan; Mirtič, Breda; Gosar, Mateja; Å turm, Sašo.; Dolenec, Matej; Jeršek, Miha

    2014-10-01

    The Jezersko meteorite is a newly confirmed stony meteorite found in 1992 in the Karavanke mountains, Slovenia. The meteorite is moderately weathered (W2), indicating short terrestrial residence time. Chondrules in partially recrystallized matrix are clearly discernible but often fragmented and have mean diameter of 0.73 mm. The meteorite consists of homogeneous olivine (Fa19.4) and low-Ca pyroxenes (Fs16.7Wo1.2), of which 34% are monoclinic, and minor plagioclase (Ab83An11Or6) and Ca-pyroxene (Fs6Wo45.8). Troilite, kamacite, zoned taenite, tetrataenite, chromite, and metallic copper comprise about 16.5 vol% of the meteorite. Phosphates are represented by merrillite and minor chlorapatite. Undulatory extinction in some olivine grains and other shock indicators suggests weak shock metamorphism between stages S2 and S3. The bulk chemical composition generally corresponds to the mean H chondrite composition. Low siderophile element contents indicate the oxidized character of the Jezersko parent body. The temperatures recorded by two-pyroxene, olivine-chromite, and olivine-orthopyroxene geothermometers are 854 °C, 737-787 °C, and 750 °C, respectively. Mg concentration profiles across orthopyroxenes and clinopyroxenes indicate relatively fast cooling at temperatures above 700 °C. A low cooling rate of 10 °C Myr-1 was obtained from metallographic data. Considering physical, chemical, and mineralogical properties, meteorite Jezersko was classified as an H4 S2(3) ordinary chondrite.

  18. New Nd-142 Evidence for a Non-Chondritic Composition of the Moon

    Science.gov (United States)

    Nyquist, L.; Touboul, M.; Kleine, T.; Bourdon, B.; Shih, C.Y.

    2009-01-01

    The coupled Sm-147,146-Nd-143,142 systematics of lunar samples has been extensively studied for estimating the timescale of lunar differentiation. The published datasets yield consistent ages for Nd isotopic closure within the lunar mantle of approx.200 Myr after CAI formation. Although this time constraint is consistent with estimates derived from Hf-W chronometry of the Moon (>60 Myr after CAI formation), there is debate as to whether this age has chronological significance. Furthermore, there are discrepancies regarding the Nd isotope composition of the bulk Moon. Rankenburg et al. obtained a epsilon Nd-142 vs. Sm-147/Nd-144 correlation for lunar samples passing though the chondritic reference value (Sm-147/Nd-144 = 0.1967, epsilon Nd-142 = -0.21), suggesting that the Moon has a chondritic bulk composition. In contrast, the other datasets define a correlation line that passes approx.10-20 ppm above, suggesting that the Moon has a superchondritic Sm-147/Nd-144 (approx.0.206), close to that of the early depleted Earth (EDM). We present new Sm-Nd data for a high-Ti mare basalt (70135), two low-Ti mare basalt (LAP 02205 and MIL 05035) and a KREEPy low-Ti mare basalt (NWA 2977). These data are used to evaluate the significance of the Sm-Nd systematics for constraining the timescale of lunar differentiation and the bulk Nd isotope composition of the Moon.

  19. Space Weathering of Ordinary Chondrite Parent Bodies, Its Impact on the Method of Distinguishing H, L, and LL Types and Implications for Itokawa Samples Returned by the Hayabusa Mission

    Science.gov (United States)

    Hiroi, T.; Sasaki, S.; Noble, S. K.; Pieters, C. M.

    2011-01-01

    As the most abundance meteorites in our collections, ordinary chondrites potentially have very important implications on the origin and formation of our Solar System. In order to map the distribution of ordinary chondrite-like asteroids through remote sensing, the space weathering effects of ordinary chondrite parent bodies must be addressed through experiments and modeling. Of particular importance is the impact on distinguishing different types (H/L/LL) of ordinary chondrites. In addition, samples of asteroid Itokawa returned by the Hayabusa spacecraft may re veal the mechanism of space weathering on an LLchondrite parent body. Results of space weathering simulations on ordinary chondrites and implications for Itokawa samples are presented here.

  20. Carbonaceous aerosols in PM10 and pollution gases in winter in Beijing

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ren-Jian; CAO Jun-ji; LEE Shun-cheng; SHEN Zhen-xing; HO Kin-Fai

    2007-01-01

    An intensive observation of organic carbon (OC) and element carbon (EC) in PM10 and gaseous materials (SO2, CO, and O3,) was conducted continuously to assess the characteristics of wintertime carbonaceous aerosols in an urban area of Beijing, China. Results showed that the averaged total carbon (TC) and PM10 concentrations in observation period are 30.2±120.4 and 172.6±198.3 μ/m3, respectively. Average OC concentration in nighttime (24.9±19.6 μ/m3) was 40% higher than that in daytime (17.7±10.9 μ/m3). Average EC concentrations in daytime (8.8±15.2 μ/m3) was close to that in nighttime (8.9±15.1 μ/m3). The OC/EC ratios in nighttime ranging from 2.4 to 2.7 are higher than that in daytime ranging from 1.9 to 2.0. The concentrations of OC, EC, PM10 were low with strong winds and high with weak winds. The OC and EC were well correlated with PM10, CO and SO2, which implies they have similar sources. OC and EC were not well correlated with O3. By considering variation of OC/EC ratios in daytime and night time, correlations between OC and O3, and meteorological condition, we speculated that OC and EC in Beijing PM10 were emitted as the primary particulate form. Emission of motor vehicle with low OC/EC ratio and coal combustion sources with high OC/EC ratio are probably the dominant sources for carbonaceous aerosols in Beijing in winter. A simple method was used to estimate the relative contribution of sources to carbonaceous aerosols in Beijing PM10. Motor vehicle source accounts for 80% and 68%, while coal combustion accounts for 20% and 32% in daytime and nighttime, respectively in Beijing. Averagely, the motor vehicle and coal combustion accounted for 74% and 26%, respectively, for carbonaceous aerosols during the observation period. It points to the motor vehicle is dominant emission for carbonaceous aerosols in Beijing PM10 in winter period, which should be paid attention to control high level of PM10 in Beijing effectively.

  1. Comets as Parent Bodies of CI1 Carbonaceous Meteorites and Possible Habitats of Ice-Microbiota

    Science.gov (United States)

    Wickramasinghe, N. Chandra; Wallis, Daryl H.; Rozanov, Alexei Yu.; Hoover, Richard B.

    2011-01-01

    Recent studies of comets and cometary dust have confirmed the presence of biologically relevant organic molecules along with clay minerals and water ice. It is also now well established by deuterium/hydrogen ratios that the CI1 carbonaceous meteorites contain indigenous extraterrestrial water. The evidence of extensive aqueous alteration of the minerals in these meteorites led to the hypothesis that water-bearing asteroids or comets represent the parent bodies of the CI1 (and perhaps CM2) carbonaceous meteorites. These meteorites have also been shown to possess a diverse array of complex organics and chiral and morphological biomarkers. Stable isotope studies by numerous independent investigators have conclusively established that the complex organics found in these meteorites are both indigenous and extraterrestrial in nature. Although the origin of these organics is still unknown, some researchers have suggested that they originated by unknown abiotic mechanisms and may have played a role in the delivery of chiral biomolecules and the origin of life on Early Earth. In this paper we review these results and investigate the thermal history of comets. We show that permanent as well as transient domains of liquid water can be maintained on a comet under a plausible set of assumptions. With each perihelion passage of a comet volatiles are preferentially released, and during millions of such passages the comet could shed crustal debris that may survive transit through the Earth s atmosphere as a carbonaceous meteorite. We review the current state of knowledge of comets and carbonaceous meteorites. We also present the results of recent studies on the long-term viability of terrestrial ice-microbiota encased in ancient glacial ice and permafrost. We suggest that the conditions which have been observed to prevail on many comets do not preclude either survivability (or even the active metabolism and growth) of many types of eukaryotic and prokaryotic microbial

  2. Spectro-microscopic measurements of carbonaceous aerosol aging in Central California

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2013-10-01

    Full Text Available Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Carbonaceous Aerosols and Radiative Effects Study (CARES was designed to study carbonaceous aerosols in the natural environment of the Central Valley, California, and learn more about their atmospheric formation and aging. This paper presents results from spectro-microscopic measurements of carbonaceous particles collected during CARES at the time of a pollution accumulation event (27–29 June 2010, when in situ measurements indicated an increase in the organic carbon content of aerosols as the Sacramento urban plume aged. Computer-controlled scanning electron microscopy coupled with an energy dispersive X-ray detector (CCSEM/EDX and scanning transmission X-ray microscopy coupled with near-edge X-ray absorption spectroscopy (STXM/NEXAFS were used to probe the chemical composition and morphology of individual particles. It was found that the mass of organic carbon on individual particles increased through condensation of secondary organic aerosol. STXM/NEXAFS indicated that the number fraction of homogenous organic particles lacking inorganic inclusions (greater than ~50 nm equivalent circular diameter increased with plume age, as did the organic mass per particle. Comparison of the CARES spectro-microscopic dataset with a similar dataset obtained in Mexico City during the MILAGRO campaign showed that fresh particles in Mexico City contained three times as much carbon as those sampled during CARES. The number fraction of soot particles at the Mexico City urban site (ranging from 16.6 to 47.3% was larger than at the CARES urban site (13.4–15.7%, and the most aged samples from CARES contained fewer carbon–carbon double bonds. Differences between carbonaceous particles in Mexico City and California result from different sources, photochemical conditions, gas phase reactants, and secondary organic aerosol

  3. Rock Magnetic Studies of the Neuschwanstein EL6 Chondrite – Implications on the Origin of its Natural Remanent Magnetization

    Czech Academy of Sciences Publication Activity Database

    Kohout, Tomáš; Donaldini, F.; Pesonen, L. J.; Uehara, M.

    2010-01-01

    Roč. 46, 1/2 (2010), s. 3-19. ISSN 0367-4231 Institutional research plan: CEZ:AV0Z30130516 Keywords : Neuschwanstein meteorite * enstatite chondrite * magnetism * paleomagnetism * remagnetization Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://www.geophysica.fi/pdf/geophysica_2010_46_1-2_003_kohout.pdf

  4. Outgassing of Ordinary Chondritic Material and Some of its Implications for the Chemistry of Asteroids, Planets, and Satellites

    CERN Document Server

    Schaefer, L; Schaefer, Laura; Fegley, Bruce

    2006-01-01

    We used chemical equilibrium calculations to model thermal outgassing of ordinary chondritic material as a function of temperature, pressure, and bulk compositions and use our results to discuss outgassing on asteroids and the early Earth. The calculations include ~1,000 solids and gases of the elements Al, C, Ca, Cl, Co, Cr, F, Fe, H, K, Mg, Mn, N, Na, Ni, O, P, S, Si, and Ti. The major outgassed volatiles from ordinary chondritic material are CH4, H2, H2O, N2, and NH3(the latter at conditions where hydrous minerals form). Contrary to widely held assumptions, CO is never the major C-bearing gas during ordinary chondrite metamorphism. The calculated oxygen fugacity (partial pressure) of ordinary chondritic material is close to that of the quartz-fayalite-iron (QFI) buffer. Our results are insensitive to variable total pressure, variable volatile element abundances, and kinetic inhibition of C and N dissolution in Fe metal. Our results predict that Earth's early atmosphere contained CH4, H2, H2O, N2, and NH3; ...

  5. Outgassing of ordinary chondritic material and some of its implications for the chemistry of asteroids, planets, and satellites

    Science.gov (United States)

    Schaefer, Laura; Fegley, Bruce

    2007-02-01

    We used chemical equilibrium calculations to model thermal outgassing of ordinary chondritic material as a function of temperature, pressure, and bulk composition and use our results to discuss outgassing on asteroids and the early Earth. The calculations include ∼1000 solids and gases of the elements Al, C, Ca, Cl, Co, Cr, F, Fe, H, K, Mg, Mn, N, Na, Ni, O, P, S, Si, and Ti. The major outgassed volatiles from ordinary chondritic material are CH4, H2, H2O, N2, and NH3 (the latter at conditions where hydrous minerals form). Contrary to widely held assumptions, CO is never the major C-bearing gas during ordinary chondrite metamorphism. The calculated oxygen fugacity (partial pressure) of ordinary chondritic material is close to that of the quartz-fayalite-iron (QFI) buffer. Our results are insensitive to variable total pressure, variable volatile element abundances, and kinetic inhibition of C and N dissolution in Fe metal. Our results predict that Earth's early atmosphere contained CH4, H2, H2O, N2, and NH3; similar to that used in Miller-Urey synthesis of organic compounds.

  6. K-Ca Dating of Alkali-Rich Fragments in the Y-74442 and Bhola LL-Chondritic Breccias

    Science.gov (United States)

    Yokoyama, T; Misawa, K.; Okano, O; Shih, C. -Y.; Nyquist, L. E.; Simon, J. I.; Tappa, M. J.; Yoneda, S.

    2013-01-01

    Alkali-rich igneous fragments in the brecciated LL-chondrites, Krahenberg (LL5) [1], Bhola (LL3-6) [2], Siena (LL5) [3] and Yamato (Y)-74442 (LL4) [4-6], show characteristic fractionation patterns of alkali and alkaline elements [7]. The alkali-rich fragments in Krahenberg, Bhola and Y-74442 are very similar in mineralogy and petrography, suggesting that they could have come from related precursor materials [6]. Recently we reported Rb-Sr isotopic systematics of alkali-rich igneous rock fragments in Y-74442: nine fragments from Y-74442 yield the Rb-Sr age of 4429 plus or minus 54 Ma (2 sigma) for lambda(Rb-87) = 0.01402 Ga(exp -1) [8] with the initial ratio of Sr-87/Sr-86 = 0.7144 plus or minus 0.0094 (2 sigma) [9]. The Rb-Sr age of the alkali-rich fragments of Y-74442 is younger than the primary Rb-Sr age of 4541 plus or minus 14 Ma for LL-chondrite whole-rock samples [10], implying that they formed after accumulation of LL-chondrite parental bodies, although enrichment may have happened earlier. Marshall and DePaolo [11,12] demonstrated that the K-40 - Ca-40 decay system could be an important chronometer as well as a useful radiogenic tracer for studies of terrestrial rocks. Shih et al. [13,14] and more recently Simon et al. [15] determined K-Ca ages of lunar granitic rocks, and showed the application of the K-Ca chronometer for K-rich planetary materials. Since alkali-rich fragments in the LL-chondritic breccias are highly enriched in K, we can expect enhancements of radiogenic Ca-40. Here, we report preliminary results of K-Ca isotopic systematics of alkali-rich fragments in the LL-chondritic breccias, Y-74442 and Bhola.

  7. Program GICC, final report (March 2005), inventory of carbonaceous aerosol particles from 1860 to 2100 or which carbonaceous aerosol for a significant climatic regional/global impact?

    International Nuclear Information System (INIS)

    The aim of our program is to determine past, present and future emission inventories of carbonaceous particles from 1860 to 2100 for fossil fuel and biofuel sources. Emission inventories for savannah and forest fires have been developed by using burnt area products given by satellite for Asia and Africa. The strong collaboration with the different groups attending this GICC program has allowed to develop the following results. 1- With the improvement of algorithms and new choices for emission factors, emission inventories for black carbon (BC), primary organic carbon (OCp) and total organic carbon (OCtot) have been constructed for the period 1950 to 1997 for fossil fuel and biofuel sources. With these new development, biofuel sources have been seen to be significant, especially in the developing countries. 2- Past inventories have been developed for fossil fuel and biofuel sources from 1860 to 1997 by taking into account the evolution of fuel consumption, fuel use and emission factors. 3- Savannah and forest fire inventories have been constructed based on burnt area products, for Africa (1981-1991, 2000) and Asia (2000-2001). These results show the importance of using real time data instead of statistics. 4-Future emission inventory of black carbon by fossil fuel sources has been constructed for 2100 following the IPCC scenario A2 (catastrophic case) and B1 (perfect world). 5-Characterization of biofuel emissions has been realized by organizing an experiment in a combustion chamber where indian and chinese biofuels (fuelwood, agricultural wastes, dung-cake etc..). were burnt, reproducing the burning methods used in these countries. 6-Finally, the differences between the existing inventories of carbonaceous aerosols has been explained. (A.L.B.)

  8. The structure and composition of metal particles in two type 6 ordinary chondrites

    Energy Technology Data Exchange (ETDEWEB)

    Holland-duffield, C.E.; Williams, D.B.; Goldstein, J.I. (Intel Corp., Albuquerque, NM (USA) Lehigh University, Bethlehem, PA (USA))

    1991-06-01

    The microstructure and composition of taenite particles were examined in two type-6 ordinary chondrites, Kernouve (H6) and Saint Severin (LL6), using reflected light microscopy and a combination of electron optical instruments. It was found that, in both meteorites, the taenite particles consisted of a narrow rim of high-Ni taenite and a central region of cloudy zone similar to those present in iron meteorites. The microstructure of the cloudy zone in Saint Severin was coarser than that in Kernouve , due to the higher Ni content and slower cooling rate of the former. Three microstructural zones were observed in the outer taenite rim of both meteorites, the origin of which is considered likely to be due to the presence of ordered domain boundaries or to the presence of two phases FeNi and FeNi3 in the high-Ni region of the outer taenite rim. 21 refs.

  9. Aerosol-Assisted Self-Assembly of Reticulated N-Doped Carbonaceous Submicron Spheres for Effective Removal of Hexavalent Chromium.

    Science.gov (United States)

    He, Jiawei; Long, Yuan; Wang, Yiyan; Wei, Chaoliang; Zhan, Jingjing

    2016-07-01

    This Research Article described a facile one-step method to prepare reticulated N-doped carbonaceous submicron spheres. Through a simple aerosol-assisted technology, glucosamine sulfate used as a carbon source was aerosolized and carbonized to functionalized carbonaceous submicron spheres. The electrostatic attraction between protonated amino groups and sulfate in the aerosol droplets induced a self-assembly and led to the formation of reticular structure, avoiding the use of templates. Compared to bare carbonaceous materials produced from glucose, reticulated N-doped carbonaceous spheres exhibit higher efficiency in the removal of Cr(VI), where the doping of element nitrogen led to electrostatic attraction between protonated nitrogen and chromium ions, and reticulated structure created relatively higher surface area and pore volume, facilitating materials to contact with Cr(VI) ions. XPS characterization proved these novel N-doped carbonaceous materials could effectively transform Cr(VI) to less toxic Cr(III) because of the surface reducing groups. For the practical application, several factors including the initial pH, materials dosage and recycle numbers on the removal performance were studied. PMID:27299376

  10. A Modeling Study of the Effects of Direct Radiative Forcing Due to Carbonaceous Aerosol on the Climate in East Asia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; WANG Zhili; GUO Pinwen; WANG Zaizhi

    2009-01-01

    The study investigated the effects of global direct radiative forcing due to carbonaceous aerosol on the climate in East Asia, using the CAM3 developed by NCAR. The results showed that carbonaceous aerosols cause negative forcing at the top of the atmosphere (TOA) and surface under clear sky conditions, but positive forcing at the TOA and weak negative forcing at the surface under all sky conditions. Hence, clouds could change the sign of the direct radiative forcing at the TOA, and weaken the forcing at the surface. Carbonaceous aerosols have distinct effects on the summer climate in East Asia. In southern China and India, it caused the surface temperature to increase, but the total cloud cover and precipitation to decrease. However, the opposite effects are caused for most of northern China and Bangladesh. Given the changes in temperature, vertical velocity, and surface streamflow caused by carbonaceous aerosol in this simulation, carbonaceous aerosol could also induce summer precipitation to decrease in southern China but increase in northern China.

  11. Dynamic behavior of an ordinary chondrite: The effects of microstructure on strength, failure and fragmentation

    Science.gov (United States)

    Hogan, James David; Kimberley, Jamie; Hazeli, Kavan; Plescia, Jeffrey; Ramesh, K. T.

    2015-11-01

    Knowledge of the relationships between microstructure, stress-state and failure mechanisms is important in the development and validation of numerical models simulating large-scale impact events. In this study, we investigate the effects of microstructural constituent phases and defects on the compressive and tensile strength, failure, and fragmentation of a stony meteorite (GRO 85209). In the first part of the paper we consider the effect of defects on the strength and failure. Strengths are measured and linked with detailed quantification of the important defects in this material. We use the defect statistic measurements in conjunction with our current understanding of rate-dependent strengths to discuss the uniaxial compressive strength measurements of this ordinary chondrite with those of another ordinary chondrite, with a different defect population. In the second part of the paper, we consider the effects of the microstructure and defects on the fragmentation of GRO 85209. Fragment size distributions are measured using image processing techniques and fragments were found to result from two distinct fragmentation mechanisms. The first is a mechanism that is associated with relatively smaller fragments arising from individual defect grains and the coalescence of fractures initiating from microstructure defects. This mechanism becomes more dominant as the strain-rate is increased. The second mechanism is associated with larger fragments that are polyphase and polygrain in character and is dependent on the structural failure mechanisms that are activated during load. In turn, these are dependent on (for example) the strain-rate, stress state, and specimen geometry. The implications of these results are briefly discussed in terms of regolith generation and catastrophic disruption.

  12. Spade: An H Chondrite Impact-melt Breccia that Experienced Post-shock Annealing

    Science.gov (United States)

    Rubin, Alan E.; Jones, Rhian H.

    2006-01-01

    The low modal abundances of relict chondrules (1.8 Vol%) and of coarse (i.e. >= 2200 micron-size) isolated mafic silicate grains (1.8 Vol%) in Spade relative to mean H6 chondrites (11.4 and 9.8 vol%, respectively) show Spade to be a rock that has experienced a significant degree of melting. Various petrographic features (e.g., chromite-plagioclase assemblages, chromite veinlets, silicate darkening) indicate that melting was caused by shock. Plagioclase was melted during the shock event and flowed so that it partially to completely surrounded nearby mafic silicate grains. During crystallization, plagioclase developed igneous zoning. Low-Ca pyroxene that crystallized from the melt (or equilibrated with the melt at high temperatures) acquired relatively high amounts of CaO. Metallic Fe-Ni cooled rapidly below the Fe-Ni solws and transformed into martensite. Subsequent reheating of the rock caused transformation of martensite into abundant duplex plessite. Ambiguities exist in the shock stage assignment of Spade. The extensive silicate darkening, the occurrence of chromite-plagioclase assemblages, and the impact-melted characteristics of Spade are consistent with shock stage S6. Low shock (stage S2) is indicated by the undulose extinction and lack of planar fractures in olivine. This suggests that Spade reached a maximum prior shock level equivalent to stage S6 and then experienced post-shock annealing (probably to stage Sl). These events were followed by a less intense impact that produced the undulose extinction in the olivine, characteristic of shock stage S2. Annealing could have occurred if Spade were emplaced near impact melts beneath the crater floor or deposited in close proximity to hot debris within an ejecta blanket. Spade firmly establishes the case for post-shock annealing. This may have been a common process on ordinary chondrites (OC) asteroids.

  13. The amino acid and hydrocarbon contents of the Paris meteorite, the most primitive CM chondrite

    Science.gov (United States)

    Martins, Zita; Modica, Paola; Zanda, Brigitte; Le Sergeant d'Hendecourt, Louis

    2015-04-01

    The Paris meteorite is reported to be the least aqueously altered CM chondrite [1,2], and to have experienced only weak thermal metamorphism [2-5]. The IR spectra of some of Paris' fragments suggest a primitive origin for the organic matter in this meteorite, similar to the spectra from solid-state materials in molecular clouds [6]. Most of the micron-sized organic particles present in the Paris matrix exhibit 0 origin or contribution from interstellar precursors. In summary, the soluble organic content of the primitive CM chondrite Paris possibly relates to late phases of condensed phase chemistry in molecular clouds. References: [1] Blanchard et al. (2011) Abstract #5322. Meteoritics and Planetary Science 46:A21. [2] Caillet Komorowski et al. (2011) Abstract #5289. Meteoritics and Planetary Science 46:A35. [3] Kimura et al. (2011) Meteoritics & Planetary Science 46:431-442. [4] Bourot-Denise et al. (2010) Abstract #1533. 41st LPSC. CD-ROM. [5] Merouane et al. (2011) Proceedings, EPSC-DPS Joint Meeting, pp.902. [6] Merouane et al. (2012) The Astrophysical Journal 756:154-160. [7] Remusat et al. (2010) The Astrophysical Journal 713:1048-1058. [8] Remusat et al. (2011) Abstract #5327. Meteoritics and Planetary Science 46:A197. [9] Martins et al. Meteoritics and Planetary Science, under review. [10] Glavin et al. (2006) Meteoritics & Planetary Science 41:889-902. [11] Glavin et al. (2010) Abstract #5131. Meteoritics and Planetary Science 45:A64. [12] Pizzarello et al. (2003) GCA 67:1589-1595. [13] Glavin and Dworkin (2009) PNAS 106:5487-5492. [14] Elsila et al. (2005) GCA 69:1349-1357.

  14. Crystal Structure Studies of Low-Ca Pyroxenes from LL-Group Chondritic Meteorites

    Science.gov (United States)

    Artioli, G.; Davoli, G.; Sighinolfi, G. P.

    1993-07-01

    One orthorhombic (Pbca) and two monoclinic (P2(sub)1/c) single crystals of low-Ca pyroxenes were extracted from unequilibrated chondritic meteorites of the LL-group. The results of the crystal structure refinements performed using x-ray diffraction data indicate that: (1) the intracrystalline Fe-Mg distribution over the M1 and M2 crystallographic sites of the Parnallee (LL-3) orthoenstatite is consistent with a temperature of 960 degrees C for the closure of the exchange equilibrium process; and (2) the structural state and intracristalline Fe-Mg order in the Soko Banja (LL-4) and Jolomba (LL-6) clinoenstatites indicate a closing temperature of at least 1000-1100 degrees C, with no significant reequilibration at lower temperatures. The present data represent the first detailed crystallographic investigation of pyroxenes from LL-chondrites and support the hypothesis that the chondrule pyroxenes bear a distinct memory of rapid cooling in the solar nebular and that thermal metamorphism in the parent body, if present, was totally unsufficient to allow reequilibration of the pyroxene minerals to the low-temperature ordered crystal structures. The data also indicate that, assuming low or mild pressure and shock effects, there is no well-defined correlation between equilibrium temperature of the mineral phases and the alleged petrologic type of the meteorites. This evidence is consistent with a rubble-pile model for the parent body accretional history, or with an onion-shell model with very low thermal-peak metamorphism, as it is assumed for a very small object.

  15. The origin of the neon isotopes in chondrites and on Earth

    Science.gov (United States)

    Moreira, Manuel; Charnoz, Sébastien

    2016-01-01

    We discuss the origin of the neon isotopic signatures in chondrites and in the terrestrial mantle. There are two primary possible origins for neon in the Earth's mantle. One origin is the dissolution of a dense primordial atmosphere with a solar composition of 20Ne/22Ne >13.4 into the mantle in a possible magma ocean stage during Earth's accretion. The second origin, developed in this study, is that mantle neon was already in Earth's parent bodies because of refractory grain irradiation by solar wind. We propose that solar wind implantation occurred early on dust within the accretion disk to allow such irradiation. Because solar wind implantation fractionates neon isotopes, the heavier isotopes are implanted deeper than the lighter ones because of different kinetic energies, and the process of implantation, if coupled with sputtering, leads to a steady state neon isotopic ratio (20Ne/22Ne ∼12.7) that is similar to what is observed in mantle-derived rocks (12.5-12.9), lunar soil grains (∼12.9) and certain gas-rich chondrites from all classes (enstatite, ordinary, rumuruti). Using a dust transport model in a turbulent and irradiated solar nebula, we estimated the equivalent irradiation age of a population of dust particles at three different distances from the sun (0.8, 1, 1.2 AU) and converted these ages into neon concentrations and isotopic ratios. The dust subsequently coagulated to form Earth's parent bodies, which have the mean neon isotopic composition of the irradiated dust (non-irradiated dust is assumed to be free of neon). If this scenario of solar wind implantation coupled with sputtering in the precursors of Earth's parent bodies is correct, it offers a simple alternative to the model of solar nebula gas incorporation by dissolution in a magma ocean.

  16. Physical characterization of a suite of Buzzard Coulee H4 chondrite fragments

    Science.gov (United States)

    Fry, C.; Melanson, D.; Samson, C.; McCausland, P. J. A.; Herd, R. K.; Ernst, R. E.; Umoh, J.; Holdsworth, D. W.

    2013-06-01

    On November 20, 2008, the Buzzard Coulee H4 chondrite fell to Earth outside of Lloydminster, Alberta, Canada. Eighteen fresh samples obtained by the National Meteorite Collection of Canada, ranging from 8.80 to 109.14 g, were investigated in this study. Physical properties of the samples were first obtained using a suite of nondestructive techniques. The bulk density (Archimedean bead method: 3.48 ± 0.04 g cm-3; 3-D laser imaging: 3.46 ± 0.03 g cm-3; micro-computed tomography: 3.44 ± 0.03 g cm-3), porosity (6.2 ± 0.1%), bulk magnetic susceptibility (log χ: 5.364 ± 0.056 × 10-9 m3 kg-1 at 825 Hz; 5.329 ± 0.052 × 10-9 m3 kg-1 at 19,000 Hz), and other derived magnetic properties (frequency dependence: 8.7 ± 6.2%; degree of anisotropy A%: 22.0 ± 2.0%; ellipsoid shape B%: -18.7 ± 8.7%) are typical of H chondrites. The coefficient of variation associated with the properties measured directly was low (0.10-1.15%), indicating that the samples are homogenous at the interfragment scale. The study then proceeded with detailed analyses at the intrafragment scale. Visual inspection of micro-computed tomographic images allowed the identification of an anomalous large clast with low metal content in a fragment. Another fragment exhibited macroscopic shock veins that warranted further examination. These fragments were cut and polished thin sections prepared for petrological analysis by optical and scanning electron microscopy. Based on mineralogical and textural similarities with several chondrules, the large clast was interpreted to be a macrochondrule. In a larger context, this study proposes a protocol for the systematic investigation of extraterrestrial material that can be exported to other new meteorite falls and finds, and specimens from sample return mission.

  17. Vanadium accumulation in carbonaceous rocks: A review of geochemical controls during deposition and diagenesis

    Science.gov (United States)

    Breit, G.N.; Wanty, R.B.

    1991-01-01

    Published data relevant to the geochemistry of vanadium were used to evaluate processes and conditions that control vanadium accumulation in carbonaceous rocks. Reduction, adsorption, and complexation of dissolved vanadium favor addition of vanadium to sediments rich in organic carbon. Dissolved vanadate (V(V)) species predominate in oxic seawater and are reduced to vanadyl ion (V(IV)) by organic compounds or H2S. Vanadyl ion readily adsorbs to particle surfaces and is added to the sediment as the particles settle. The large vanadium concentrations of rocks deposited in marine as compared to lacustrine environments are the result of the relatively large amount of vanadium provided by circulating ocean water compared to terrestrial runoff. Vanadium-rich carbonaceous rocks typically have high contents of organically bound sulfur and are stratigraphically associated with phosphate-rich units. A correspondence between vanadium content and organically bound sulfur is consistent with high activities of H2S during sediment deposition. Excess H2S exited the sediment into bottom waters and favored reduction of dissolved V(V) to V(IV) or possibly V(III). The stratigraphic association of vanadiferous and phosphatic rocks reflects temporal and spatial shifts in bottom water chemistry from suboxic (phosphate concentrated) to more reducing (euxinic?) conditions that favor vanadium accumulation. During diagenesis some vanadium-organic complexes migrate with petroleum out of carbonaceous rocks, but significant amounts of vanadium are retained in refractory organic matter or clay minerals. As carbon in the rock evolves toward graphite during metamorphism, vanadium is incorporated into silicate minerals. ?? 1991.

  18. Microfossils, biomolecules and biominerals in carbonaceous meteorites: implications to the origin of life

    Science.gov (United States)

    Hoover, Richard B.

    2012-11-01

    Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) investigations have shown that a wide variety of carbonaceous meteorites contain the remains of large filaments embedded within freshly fractured interior surfaces of the meteorite rock matrix. The filaments occur singly or in dense assemblages and mats and are often encased within carbon-rich, electron transparent sheaths. Electron Dispersive X-ray Spectroscopy (EDS) spot analysis and 2D X-Ray maps indicate the filaments rarely have detectable nitrogen levels and exhibit elemental compositions consistent with that interpretation that of the meteorite rock matrix. Many of the meteorite filaments are exceptionally well-preserved and show evidence of cells, cell-wall constrictions and specialized cells and processes for reproduction, nitrogen fixation, attachment and motility. Morphological and morphometric analyses permit many of the filaments to be associated with morphotypes of known genera and species of known filamentous trichomic prokaryotes (cyanobacteria and sulfur bacteria). The presence in carbonaceous meteorites of diagenetic breakdown products of chlorophyll (pristane and phytane) along with indigenous and extraterrestrial chiral protein amino acids, nucleobases and other life-critical biomolecules provides strong support to the hypothesis that these filaments represent the remains of cyanobacteria and other microorganisms that grew on the meteorite parent body. The absence of other life-critical biomolecules in the meteorites and the lack of detectable levels of nitrogen indicate the filaments died long ago and can not possibly represent modern microbial contaminants that entered the stones after they arrived on Earth. This paper presents new evidence for microfossils, biomolecules and biominerals in carbonaceous meteorites and considers the implications to some of the major hypotheses for the Origin of Life.

  19. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, M.A. [Brookhaven National Lab., Upton, NY (United States); Cofer, W.R. III; Levine, J.S. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center

    1990-10-01

    The identity and ambient mass concentrations of radiatively important carbonaceous aerosols were measured for a boreal forest prescribed burn conducted in northern Ontario, CAN in August 1989. Nonsize-segregated airborne particles were collected for smoldering-fire and full-fire conditions using a helicopter sampling platform. Total carbon (TC), organic carbon (OC) and elemental carbon (EC) were measured. Smoke plume mass concentrations of the OC and EC particles were greatest for full-fire conditions and had ranges of 1.560 to 2.160 mg/m{sup {minus}1} (OC) and 0.120 to 0.160 mg/m{sup {minus}3} (EC) with OC:EC ratios of 10 to 18, respectively. Smoldering fire conditions showed smoke plume OC and EC levels of 0.570--1.030 mg/m{sup {minus}3} (OC) and 0.006--0.050 mg/m{sup {minus}3} (EC) and much higher ratios of OC:EC (21 to 95). These aerosol data indicate the formation of EC particles is greatest during full-fire combustion of boreal forest material relative to smoldering combustion. However, EC particles comprise a minor fraction of the particulate carbon smoke aerosols for both full-fire and smoldering conditions; the major component of carbonaceous smoke aerosols emitted during the prescribed burn is OC. Overall, the OC and EC in-plume smoke aerosol data show nonuniform production of these particles during various stages of the prescribed burn, and major differences in the type of carbonaceous aerosol that is generated (OC versus EC).

  20. Calculations of the mass absorption cross sections for carbonaceous nanoparticles modeling soot

    International Nuclear Information System (INIS)

    In this paper we use an atomistic model to calculate the mass specific absorption cross section coefficient (MAC) of carbonaceous particles of nanometer size. The carbonaceous particles are built numerically to reproduce most of the structural characteristics of typical primary nanoparticles that are agglomerated in soot emitted in the Troposphere from combustion sources. Our model is based on the knowledge of the atomic positions and polarizabilities inside the primary nanoparticles and is used to study the influence of these atomistic characteristics on the optical properties of these nanoparticles. The results indicate that the atomistic composition of the soot primary nanoparticles may have a sufficiently strong impact on the mass specific absorption cross section coefficient curves to allow detection of differences between nanoparticles by using UV–visible spectroscopic measurements, in a well-suited wavelength range, i.e., typically between 200 and 350 nm. In a more general way, our calculations show that MAC values as well as differences between MAC curves corresponding to different primary nanoparticles may strongly vary with wavelength. As a consequence, measurements at a given wavelength only are certainly not representative of the absorption properties of these nanoparticles and thus should be considered with caution. Moreover, our approach clearly shows significant differences with classical macroscopic electromagnetic theory when calculating the optical properties of realistic primary soot nanoparticles that, in fact, cannot be considered as homogeneous spherical particles due to the presence of defects in their atomistic structure. - Highlights: • We calculate the MAC curves of carbonaceous particles. • Relation between atomistic characteristics and MAC curves is characterized. • We show that MAC curves depend on the atomistic composition of the nanoparticles • Difference between nanoparticles may be characterized by spectroscopic

  1. Carbon isotope analysis of carbonaceous compounds in Puget Sound and Lake Washington

    International Nuclear Information System (INIS)

    A new method has been developed and tested for determining chronological profiles of organic pollutants. This method, Carbon Isotope Analysis (CIA), involves measurements of 12C, 13C and 14C in carbonaceous compounds found in layers of sediment. Lipids, total aliphatic hydrocarbons (TAHs) and polycyclic aromatic hydrocarbons (PAHs) are separated from kg quantities of sediment. Large Soxhlet extractors are used to remove the extractable organics, using ultra-pure benzene-methanol solution and having an extraction efficiency of about 86% for compounds with boiling points higher than n-tetradecane (n-C14). The basic steps in compound separation include freeze-drying, extraction, fractionation, column chromatography and evaporation. Isolating the TAH and PAH fractions is accomplished by eluting samples from Sephadex and alumina/silica-gel columns. The amount of each fraction recovered is determined by converting the hydrocarbons to carbon dioxide and measuring this gas manometrically. Variations in 12C and 13C abundances for carbonaceous compounds are primarily due to thermodynamic, photosynthetic and metabolic fractionation processes. Thus, the source of a particular organic compound can often be determined by measuring its 13C/12C ratio. Combining the information from both the 13C analysis and 14C analysis makes source identification more certain. In addition, this investigation reviews carbon isotopic data and carbon cycling and analyzes organic pollution in two limited ecosystems (Puget Sound and Lake Washington). Specifically, distinct carbonaceous species are analyzed for pollution in sediments of Lake Washington, Elliott Bay, Commencement Bay, central Puget Sound and northern Puget Sound near the Cherry Point oil refineries

  2. Origin and formation of carbonaceous material veins in the 2008 Wenchuan earthquake fault zone

    Science.gov (United States)

    Liu, Jiang; Li, Haibing; Zhang, Jinjiang; Zhang, Bo

    2016-02-01

    This paper establishes a reference data set of carbonaceous materials (CMs) from the active fault zone of the Longmen Shan fault belt that ruptured in the 2008 Mw7.9 Wenchuan earthquake and presents an application of these data for studies of both other exhumed carbonaceous-rich fault zones and deep-drilling cores. The CMs distributed in the active fault zone are found as narrow veins and located along the slip surfaces. Microstructural observation shows that the carbonaceous material veins (CMVs) are located along slip surfaces in the fault gouge zones. Some CMVs have a cataclastic fabric, and their branches intrude into voids around the slip surfaces. Raman spectra of the CMVs show a wide (full width at half maximum >200 cm-1) D-peak at ~1345 cm-1 (defect peak), which is much lower than the O-peak at ~1595 cm-1 (ordered peak), indicating a metamorphic temperature of zeolite facies or lower than 250 °C. In addition, the stable carbon isotopic compositions (δ13C values) of the CMVs, ranging from -23.4 to -26.4‰, are very similar to that of the kerogen collected from the Late Triassic Xujiahe Formation in Sichuan Basin. Given the data at which it may be formed, the Xujiahe Formation is the most likely origin of CMs for the CMVs, and it seems that some CMVs in the fault zone were crushed and intruded into the voids during coseismic events, possibly driven by an enhanced pore fluid pressure. Since graphitization is suggested as an indicator of transient frictional heating in this area, our study providing a reference data set of CMs would help future CM-rich fault-zone research to retrieve seismic signatures presumably occurring in the Longmen Shan fault zone belt.

  3. Radiocarbon (14C) source apportionment of carbonaceous aerosol components in the Asian Atmospheric Brown Cloud

    International Nuclear Information System (INIS)

    Full text: Light-absorbing carbonaceous matter constitutes one of the largest uncertainties in climate modeling. The high concentrations of black carbon - soot - in the Asian Brown Cloud lead to strong atmospheric heating and large surface cooling that is as important to regional climate forcing as greenhouse gases, yet the sources of these aerosols are not well understood. Emission inventory models suggest that biofuel/biomass burning accounts for 60 - 90 % of the sources of these aerosol components whereas measurements of the elemental composition of ambient aerosols compared with source signatures point to combustion of fossil fuel as the primary culprit. However, both approaches acknowledge large uncertainties in source apportionment of the elusively defined black carbon. This study approached the sourcing challenge by applying microscale radiocarbon measurements to aerosol particles collected during the winter monsoon both over the Indian Ocean and in central India. The radiocarbon approach is ideally suited to this task as fossil sources are void of 14C whereas biomass combustion products hold a contemporary 14C signal. High-volume air samples of total carbonaceous aerosols revealed 14C signals that were similar for N. Indian source and Indian Ocean receptor regions, consistent with the absence of any significant formation of secondary organic aerosols, with a 60 - 70 % contribution from biomass combustion and biogenic sources. Isolates of elemental or soot carbon fractions varied between 40 - 70 %, depending on isolation method. These novel radiocarbon constraints on the sources of light-absorbing carbonaceous matter aid prioritizing of what combustion processes to target for emission mitigations of these health-afflicting and climate-forcing aerosols in the South Asian region. (author)

  4. Characteristics and major sources of carbonaceous aerosols in PM2.5 from Sanya, China

    International Nuclear Information System (INIS)

    PM2.5 samples were collected in Sanya, China in summer and winter in 2012/2013. Organic carbon (OC), elemental carbon (EC), and non-polar organic compounds including n-alkanes (n-C14-n-C40) and polycyclic aromatic hydrocarbons (PAHs) were quantified. The concentrations of these carbonaceous matters were generally higher in winter than summer. The estimated secondary organic carbon (OCsec) accounted for 38% and 54% of the total organic carbon (TOC) in winter and summer, respectively. The higher value of OCsec in addition to the presences of photochemically-produced PAHs in summer supports that photochemical conversions of organics are much active at the higher air temperatures and with stronger intense solar radiation. Carbon preference index (CPI) and percent contribution of wax n-alkanes suggest that anthropogenic sources were more dominant than derivation from terrestrial plants in Sanya. Diagnostic ratios of atmospheric PAHs further indicate that there was a wide mix of pollution sources in winter while fossil fuel combustion was the most dominant in summer. Positive Matrix Factorization (PMF) analysis with 18 PAHs in the winter samples found that motor vehicle emissions and biomass burning were the two main pollution sources, contributing 37.5% and 24.6% of the total quantified PAHs, respectively. - Highlights: • The first comprehensive study to investigate carbonaceous PM2.5 in Sanya, China • Higher carbonaceous levels in winter while more SOC formation in summer • Anthropogenic emission is the dominant sources of n-alkanes • Vehicle emission and biomass burning contributed ≥60% of the total PAHs in winter • The result supports better air quality in Sanya than most megacities in China

  5. Indigenous Carbonaceous Phases Embedded Within Surface Deposits on Apollo 17 Volcanic Glass Beads

    Science.gov (United States)

    Thomas-Keprta, K. L.; Clemett, S. J.; Ross, D. K.; Le, L.; McKay, D. S.; Gibson, E. K.; Gonzalez, C.

    2012-01-01

    The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. Prior studies of Apollo samples have shown the total amount of organic matter to be in the range of approx 50 to 250 ppm. Low concentrations of lunar organics may be a consequence not only of its paucity but also its heterogeneous distribution. Several processes should have contributed to the lunar organic inventory including exogenous carbonaceous accretion from meteoroids and interplanetary dust particles, and endogenous synthesis driven by early planetary volcanism and cosmic and solar radiation.

  6. Studying properties of carbonaceous reducers and process of forming primary titanium slags

    Directory of Open Access Journals (Sweden)

    T. K. Balgabekov

    2014-10-01

    Full Text Available When smelting a rich titanium slag the most suitable are low-ash reducers, and the studies revealed the suitability for this purpose of special coke and coal. An important property of a reducer is its specific resistance. Therefore there were carried out studies for measuring electric resistance of briquettes consisting of ilmenite concentrate and different carbonaceous reducers. It is recommended to jointly smelt the briquetted and powdered burden (the amount of the powdered burden varies form 20 tо 50 %, this leads to the increase of technical-economic indicators of the process.

  7. Method and apparatus for conversion of carbonaceous materials to liquid fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lux, Kenneth W.; Namazian, Mehdi; Kelly, John T.

    2015-12-01

    Embodiments of the invention relates to conversion of hydrocarbon material including but not limited to coal and biomass to a synthetic liquid transportation fuel. The invention includes the integration of a non-catalytic first reaction scheme, which converts carbonaceous materials into a solid product that includes char and ash and a gaseous product; a non-catalytic second reaction scheme, which converts a portion of the gaseous product from the first reaction scheme to light olefins and liquid byproducts; a traditional gas-cleanup operations; and the third reaction scheme to combine the olefins from the second reaction scheme to produce a targeted fuel like liquid transportation fuels.

  8. Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites: Implications to Life on Comets, Europa and Enceladus

    Science.gov (United States)

    Hoover, Richard B.

    2011-10-01

    Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations of the internal surfaces of the CI1 Carbonaceous Meteorites have yielded images of large complex filaments. The filaments have been observed to be embedded in freshly fractured internal surfaces of the stones. They exhibit recognizable features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of filamentous trichomic cyanobacteria and other trichomic prokaryotes (such as filamentous sulfur bacteria). ESEM and FESEM studies of living and fossil cyanobacteria show features similar to the filaments found in the meteorites -- uniseriate and multiseriate, branched or unbranched, isodiametric or tapered, polarized or unpolarized filaments with trichomes encased within thin or thick external sheaths. Some of the filaments found in the CI1 meteorites also exhibit specialized cells and structures used by cyanobacteria for reproduction (baeocytes, akinetes and hormogonia), nitrogen fixation (basal, intercalary or apical heterocysts), attachment (pili or fimbriae) or indicative of oscillatoria type locomotion (escaped or coiling hormogonia and flattened and coiled empty sheaths). Energy dispersive X-ray Spectroscopy (EDS) studies indicate that the Orgueil meteorite filaments are typically carbon-rich sheaths infilled with magnesium sulfate and other minerals characteristic of the CI1 carbonaceous meteorites. However, the size, structure, detailed morphological characteristics and chemical compositions of the meteorite filaments are not consistent with known species of abiotic minerals. The nitrogen content of the meteorite filaments are almost always below the detection limit of the EDS detector. EDS analysis of living and dead biological materials (e.g., filamentous cyanobacteria; bacteria, mummy and mammoth hair and tissues, and fossils of cyanobacteria, trilobites and insects in

  9. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Directory of Open Access Journals (Sweden)

    Ana Arenillas

    2013-10-01

    Full Text Available Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar and capacities (>2 mmol·g−1 at 273 K. Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes.

  10. Carbonaceous aerosol over semi-arid region of western India: Heterogeneity in sources and characteristics

    Science.gov (United States)

    Sudheer, A. K.; Aslam, M. Y.; Upadhyay, M.; Rengarajan, R.; Bhushan, R.; Rathore, J. S.; Singh, S. K.; Kumar, S.

    2016-09-01

    Carbonaceous species (elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC)) and water-soluble inorganic species (Na+, NH4+, K+, Ca2 +, Mg2 +, Cl-, NO3-, SO42 -) in PM10 and PM2.5 from Ahmedabad and Jodhpur (urban and semi-urban locations, respectively) in western India were measured during May-September, 2011. Stable isotope composition of carbonaceous aerosol (δ13C of TC) in PM10 samples was also determined. Average EC concentration in PM10 at Ahmedabad was 1 μg m- 3 (range: 0.34 to 3.4 μg m- 3), almost 80% of which remained in PM2.5. Similarly, 70% of EC in PM10 (average: 0.9 μg m- 3) resided in PM2.5 at Jodhpur. Average OC concentration at Ahmedabad was 6.4 μg m- 3 and ~ 52% of this was found in PM2.5. On the contrary, OC concentration at Jodhpur was 40 μg m- 3, 80% of which was found in coarse particles contributing substantially to aerosol mass. δ13C of TC (average: - 27.5‰, range: - 29.6 to - 25.8‰) along with WSOC/EC ratio shows an increasing trend at Jodhpur suggesting the possibility of aging of aerosol, since aging results in enrichment of heavier isotope. OC and WSOC show significant correlations with K+ and not with EC, indicating biogenic origin of OC. Different size distributions are also exhibited by WSOC at the two stations. On the other hand, δ13C exhibits an inverse trend with sea-salt constituents at Ahmedabad, indicating the influence of air masses transported from the western/south-western region on carbonaceous aerosol. These results suggest that a strong heterogeneity exists in the sources of carbonaceous aerosol over this region and potential sources of non-combustion emissions such as bio-aerosol that need further investigation.

  11. Carbonaceous aerosols and pollutants over Delhi urban environment: Temporal evolution, source apportionment and radiative forcing

    International Nuclear Information System (INIS)

    Particulate matter (PM2.5) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO42− and NO3−) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM2.5 samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO42− and NO3−). Furthermore, continuous (online) measurements of PM2.5 (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM2.5 (online) range from 18.2 to 500.6 μg m−3 (annual mean of 124.6 ± 87.9 μg m−3) exhibiting higher night-time (129.4 μg m−3) than daytime (103.8 μg m−3) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO3−and SO42−, which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R2 = 0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~ 1.8–2.0 K day−1) due to agricultural burning effects during the 2012 post-monsoon season. - Highlights: • Very high PM2.5 (> 200 µg m−3) levels over Delhi during agricultural

  12. Carbonaceous aerosols and pollutants over Delhi urban environment: Temporal evolution, source apportionment and radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Bisht, D.S. [Indian Institute of Tropical Meteorology, New Delhi (India); Dumka, U.C., E-mail: dumka@aries.res.in [Aryabhatta Research Institute of Observational Sciences, Nainital (India); Kaskaoutis, D.G. [School of Natural Sciences, Shiv Nadar University, Tehsil Dadri (India); Pipal, A.S. [Department of Chemistry, Savitribai Phule Pune University, Pune (India); Srivastava, A.K. [Indian Institute of Tropical Meteorology, New Delhi (India); Soni, V.K.; Attri, S.D.; Sateesh, M. [India Meteorology Department, Lodhi Road, New Delhi (India); Tiwari, S. [Indian Institute of Tropical Meteorology, New Delhi (India)

    2015-07-15

    Particulate matter (PM{sub 2.5}) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO{sub 4}{sup 2−} and NO{sub 3}{sup −}) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM{sub 2.5} samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO{sub 4}{sup 2−} and NO{sub 3}{sup −}). Furthermore, continuous (online) measurements of PM{sub 2.5} (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM{sub 2.5} (online) range from 18.2 to 500.6 μg m{sup −3} (annual mean of 124.6 ± 87.9 μg m{sup −3}) exhibiting higher night-time (129.4 μg m{sup −3}) than daytime (103.8 μg m{sup −3}) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO{sub 3}{sup −}and SO{sub 4}{sup 2−}, which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R{sup 2} = 0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~ 1.8–2.0 K day{sup −1}) due to agricultural burning effects

  13. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave

    OpenAIRE

    Tong-Chao Su; Zhen Fang; Fan Zhang; Jia Luo; Xing-Kang Li

    2015-01-01

    In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g−1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg−1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% und...

  14. Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

    International Nuclear Information System (INIS)

    Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir-Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).

  15. Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Segura, E. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon y Tollocan s/n., C.P. 50000 Toluca (Mexico); Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Solache-Rios, M., E-mail: marcos.solache@inin.gob.mx [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Colin-Cruz, A. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon y Tollocan s/n., C.P. 50000 Toluca (Mexico)

    2009-10-30

    Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir-Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).

  16. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    International Nuclear Information System (INIS)

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N2 adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m2 g−1) and pore volume (0.016 cm3 g−1), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m2 g−1 and 0.701 cm3 g−1, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH2) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH2 bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds

  17. Reconstruction of exposure histories of meteorites from Antarctica and the Sahara

    International Nuclear Information System (INIS)

    10Be, 14C, and 26Al were analyzed in H-, L-, and LL-chondrites from the Acfer region in the Algerian Sahara and from the Allan Hills/Antarctica. Exposure histories and terrestrial ages could be determined. (author) 3 figs., 2 refs

  18. Reconstruction of exposure histories of meteorites from Antarctica and the Sahara

    Energy Technology Data Exchange (ETDEWEB)

    Neupert, U.; Neumann, S.; Leya, I.; Michel, R. [Hannover Univ. (Germany). Zentraleinrichtung fuer Strahlenschutz (ZfS); Kubik, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Bonani, G.; Hajdas, I.; Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    {sup 10}Be, {sup 14}C, and {sup 26}Al were analyzed in H-, L-, and LL-chondrites from the Acfer region in the Algerian Sahara and from the Allan Hills/Antarctica. Exposure histories and terrestrial ages could be determined. (author) 3 figs., 2 refs.

  19. Production of activated charcoal beads or green moldnings useful in stationary or fluidized bed uses rotary stirrer(s) for mixing carbonaceous powder with binder

    DEFF Research Database (Denmark)

    2000-01-01

    In the production of activated charcoal beads or green moldings by mixing carbonaceous powder with a binder, mixing is carried out in a stirred vessel with rotary stirrer(s).......In the production of activated charcoal beads or green moldings by mixing carbonaceous powder with a binder, mixing is carried out in a stirred vessel with rotary stirrer(s)....

  20. Performance of a diffusion denuder for the elimination of sampling artifacts for carbonaceous aerosols at three urban and two forested sites in Europe

    Czech Academy of Sciences Publication Activity Database

    Maenhaut, W.; Chi, X.; Viana, M.; Mikuška, Pavel; Večeřa, Zbyněk

    Berkeley, 2008. s. 102. [International Conference on Carbonaceous Particles in the Atmosphere /9./. 12.08.2008-14.08.2008, Berkeley, California] Institutional research plan: CEZ:AV0Z40310501 Keywords : filter sampling artifacts * diffusion denuder * carbonaceous aerosol Subject RIV: CB - Analytical Chemistry, Separation

  1. On the effect of gold nanoparticles loading within carbonaceous macro-mesocellular foams toward lithium-sulfur battery performances

    Science.gov (United States)

    Depardieu, Martin; Demir-Cakan, Rezan; Sanchez, Clément; Birot, Marc; Deleuze, Hervé; Morcrette, Mathieu; Backov, Rénal

    2016-05-01

    Novel carbonaceous monolith foams loaded with gold nanoparticles have been synthesized and thoroughly characterized over several length scale. Their Li-S battery electrode capabilities have been assessed and compared while varying the gold loading and subsequently the specific surface area. Their capacities expressed in either mass (mA h g-1) or volume (mA h cm-3) dimensions have shown that specific surface area and nanoparticles loading are acting in a strong partitioning mode, rather than a cooperative mode, which does not favor the use of gold nanoparticles loading as efficient incremental path toward optimizing porous carbonaceous-based Li-S battery electrodes.

  2. Removal of carbonaceous and nitrogenous pollutants from a synthetic wastewater using a membrane-coupled bioreactor.

    Science.gov (United States)

    Ghosh, Sudeshna; LaPara, Timothy M

    2004-09-01

    Two modified Ludzack-Ettinger (MLE)-type membrane-coupled bioreactors (MBRs) were investigated in this study for the purpose of removing both nitrogenous and carbonaceous pollutants from a synthetic wastewater. During the first MBR experiment, removal efficiencies were high (>90%) for chemical oxygen demand (COD) and ammonia, but total nitrogenous pollutant removal efficiency was poor (approximately 25%). Bacterial community analysis of ammonia oxidizing bacteria (AOB) by a nested PCR-DGGE approach detected two Nitrosomonas-like populations and one Nitrosospira-like population. During the initial portion of the second MBR experiment, COD and ammonia removal efficiencies were similar to the first MBR experiment until the COD of the influent wastewater was increased to provide additional electron donors to support denitrification. Total nitrogen removal efficiencies eventually exceeded 90%, with a hydraulic residence time (HRT) of 24 h and a recirculation ratio of 8. When the HRT of the MBR experiment was decreased to 12 h, however, ammonia removal efficiency was adversely affected. A subsequent increase in the HRT to 18 h helped improve removal efficiencies for both ammonia (>85%) and total nitrogenous compounds (approximately 70%). Our research demonstrates that MBRs can be effectively designed to remove both carbonaceous and nitrogenous pollutants. The ability of the microbial community to switch between anoxic (denitrifying) and oxic (nitrifying) conditions, however, represents a critical process constraint for the application of MLE-type MBR systems, such that little benefit is gained compared to conventional designs. PMID:15338423

  3. Carbonaceous thin film coating with Fe-N4 site for enhancement of dioxovanadium ion reduction

    Science.gov (United States)

    Maruyama, Jun; Hasegawa, Takahiro; Iwasaki, Satoshi; Fukuhara, Tomoko; Orikasa, Yuki; Uchimoto, Yoshiharu

    2016-08-01

    It has been found that carbonaceous materials containing a transition metal coordinated by 4 nitrogens in the square-planar configuration (metal-N4 site) on the surface possessed a catalytic activity for various electrochemical reactions related to energy conversion and storage; i.e., oxygen reduction, hydrogen evolution, and quite recently, the electrode reactions in vanadium redox flow batteries (VRFB). The catalyst for the VRFB positive electrode discharge reaction, i.e., the dioxovanadium ion reduction, was formed by coating the surface of cup-stack carbon nanotubes with a carbonaceous thin film with the Fe-N4 site generated by the sublimation, deposition, and pyrolysis of iron phthalocyanine. In this study, the influence of the physical properties of the catalyst on the electrochemical reactions was investigated to optimize the coating. With an increase in the coating, the specific surface area increased, whereas the pore size decreased. The surface Fe concentration was increased in spite of the Fe aggregation inside the carbon matrix. The catalytic activity enhancement was achieved due to the increase in the specific surface area and the surface Fe concentration, but was lowered due to the decrease in the pore size, which was disadvantageous for the penetration of the electrolyte and the mass transfer.

  4. Testing for fullerenes in geologic materials: Oklo carbonaceous substances, Karelian shungites, Sudbury Black Tuff

    Science.gov (United States)

    Mossman, David; Eigendorf, Guenter; Tokaryk, Dennis; Gauthier-Lafaye, François; Guckert, Kristal D.; Melezhik, Victor; Farrow, Catharine E. G.

    2003-03-01

    Fullerenes have been reported from diverse geologic environments since their discovery in shungite from Karelian Russia. Our investigation is prompted by the presence of onionskin-like structures in some carbonaceous substances associated with the fossil nuclear fission reactors of Oklo, Gabon. The same series of extractions and the same instrumental techniques, laser desorption ionization and high-resolution mass spectroscopy (electron-impact mass spectroscopy), were employed to test for fullerenes in samples from three different localities: two sites containing putative fullerenes (Sudbury Basin and Russian Karelia) and one new location (Oklo, Gabon). We confirm the presence of fullerenes (C60 and C70) in the Black Tuff of the Onaping Formation impact breccia in the Sudbury Basin, but we find no evidence of fullerenes in shungite samples from various locations in Russian Karelia. Analysis of carbonaceous substances associated with the natural nuclear fission reactors of Oklo yields no definitive signals for fullerenes. If fullerenes were produced during sustained nuclear fission at Oklo, then they are present below the detection limit (˜100 fmol), or they have destabilized since formation. Contrary to some expectations, geologic occurrences of fullerenes are not commonplace.

  5. Characterization of the carbonaceous materials obtained from different agro-industrial wastes.

    Science.gov (United States)

    Ensuncho-Muñoz, A E; Carriazo, J G

    2015-01-01

    This paper reports the preparation and characterization of carbonaceous materials obtained from three types of vegetable wastes provided by agricultural industries. Soft carbonization (280°C) and H3PO4-activation procedures were used to convert the agricultural wastes to carbon powders with high adsorbent capacities. This process is excellent for eliminating and exploiting the huge masses (many tons) of vegetable residues remaining after each harvest every year in several Colombian agro-industries. The powders were characterized by X-ray diffraction (XRD), IR spectroscopy, scanning electron microscopy (SEM), and N2-adsorption isotherms. XRD and IR verified the formation of carbons, and SEM showed small particles (20-500 µm) with characteristic morphology for each type of residue used and abundant cavities of different sizes. The N2-adsorption analyses showed that the carbons had high adsorption capacities with important surface area values and large pore volumes. The use of the activated carbonaceous materials as adsorbent of azo dyes (allura red and sunset yellow) from aqueous solutions was evaluated. The results showed a good adsorption capacity indicating the potentiality of these materials as pollutant adsorbents in food industry wastewaters. These results indicate that these powders can be used as potential adsorbents for different gaseous or liquid pollutants. PMID:25189634

  6. Precursor soot synthesis of fullerenes and nanotubes without formation of carbonaceous soot

    Science.gov (United States)

    Reilly, Peter T. A.

    2007-03-20

    The present invention is a method for the synthesis of fullerenes and/or nanotubes from precursor soot without the formation of carbonaceous soot. The method comprises the pyrolysis of a hydrocarbon fuel source by heating the fuel source at a sufficient temperature to transform the fuel source to a condensed hydrocarbon. The condensed hydrocarbon is a reaction medium comprising precursor soot wherein hydrogen exchange occurs within the reaction medium to form reactive radicals which cause continuous rearrangement of the carbon skeletal structure of the condensed hydrocarbon. Then, inducing dehydrogenation of the precursor soot to form fullerenes and/or nanotubes free from the formation of carbonaceous soot by continued heating at the sufficient temperature and by regulating the carbon to hydrogen ratio within the reaction medium. The dehydrogenation process produces hydrogen gas as a by-product. The method of the present invention in another embodiment is also a continuous synthesis process having a continuous supply of the fuel source. The method of the present invention can also be a continuous cyclic synthesis process wherein the reaction medium is fed back into the system as a fuel source after extraction of the fullerenes and/or nanotube products. The method of the present invention is also a method for producing precursor soot in bulk quantity, then forming fullerenes and/or nanotubes from the precursor bulk.

  7. Sorption / desorption hysteresis of non-polar organic compounds in carbonaceous materials

    Science.gov (United States)

    Wang, G.; Kleineidam, S.; Grathwohl, P.

    2003-04-01

    Natural and thermally-altered carbonaceous materials (coals, charcoal, cokes) are nowadays found in many soil and sediment samples due to anthropogenic impact (e.g. industrial activities, traffic) to the natural environment. The sorption -- desorption characteristics of hydrophobic organic compounds on that type of geosorbents play an important role in contaminant fate and transport and are yet not precisely known. Contaminant transport and bioavailibility models often assume complete sorption reversibility. In this study, a series of desorption steps using the ASE (accelerated solvent extractor) with water at different temperatures were carried out to determine the desorption enthalpy and to study hysteresis phenomena. The initial natural loading of PAHs onto the geosorbents was determined by solvent extraction (acetone and toluene). The background loading is in the order of 0.8 mg kg-1 -- 102 mg kg-1 for the natural coals and in the order of 0.16 mg kg-1 -- 10 mg kg-1 for the thermally altered coals. The results are compared to kinetic and equilibrium data from laboratory experiments on sorptive uptake of the phenanthrene onto the same carbonaceous samples.

  8. The interplay between chemistry and nucleation in the formation of carbonaceous dust in supernova ejecta

    CERN Document Server

    Lazzati, Davide

    2015-01-01

    Core-collapse supernovae are considered to be important contributors to the primitive dust enrichment of the interstellar medium in the high-redshift universe. Theoretical models of dust formation in stellar explosions have so far provided controversial results and a generally poor fit to the observations of dust formation in local supernovae. We present a new methodology for the calculation of carbonaceous dust formation in young supernova remnants. Our new technique uses both the nucleation theory and a chemical reaction network to allow us to compute the dust growth beyond the molecular level as well as to consider chemical erosion of the forming grains. We find that carbonaceous dust forms efficiently in the core of the ejecta, but takes several years to condensate, longer than previously estimated. It forms unevenly and remains concentrated in the inner part of the remnant. These results support the role of core-collapse supernovae as dust factories and provide new insight on the observations of SN 1987A...

  9. Comparison of carbonaceous particulate matter emission factors among different solid fuels burned in residential stoves

    Science.gov (United States)

    Shen, Guofeng; Xue, Miao; Chen, Yuanchen; Yang, Chunli; Li, Wei; Shen, Huizhong; Huang, Ye; Zhang, Yanyan; Chen, Han; Zhu, Ying; Wu, Haisuo; Ding, Aijun; Tao, Shu

    2014-06-01

    Uncertainty in the emission factor (EF) usually contributes largely to the overall uncertainty in the emission inventory. In the present study, the locally measured EFs of particulate matter (PM), organic carbon (OC), and elemental carbon (EC) for solid fuels burned in the residential sector are compiled and compared. These fuels are classified into seven sub-groups of anthracite briquette, anthracite chunk, bituminous briquette, bituminous chunk, crop residue, fuel wood log, and brushwood/branches. The EFs of carbonaceous particles for these fuels vary significantly, generally in the order of anthracite (briquette and chunk) briquette and chunk), with an exception that the brushwood/branches have a relatively high EF of EC. The ratio of EC/OC varies significantly among different fuels, and is generally higher for biomass fuel than that for coal because of the intense flaming conditions formed during the biomass burning process in improved stoves. Distinct ratios calls for a future study on the potential health and climate impacts of carbonaceous PM from the residential combustions of different fuels. A narrow classification of these fuels significantly reduces the variations in the EFs of PM, OC, and EC, and the temporal and geographical distributions of the emissions could be better characterized.

  10. Characteristics of Anthropogenic Sulfate and Carbonaceous Aerosols over East Asia: Regional Modeling and Observation

    Institute of Scientific and Technical Information of China (English)

    Yan HUANG; William L. CHAMEIDES; Qian TAN; Robert E. DICKINSON

    2008-01-01

    The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO42-, hydrophobic and hydrophilic black carbon (BC) and organic carbon compounds (OC), including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion (especially in the aqueous phase) and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO42- shows less horizontal gradient and seasonality than SO2, with wet deposition (60%) and export (27%) being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition (60%) and export (30%). The simulated spatial and seasonal SO42-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.

  11. Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

    Science.gov (United States)

    Cooper, George; Rios, Andro C.

    2016-06-01

    Biological polymers such as nucleic acids and proteins are constructed of only one—the d or l—of the two possible nonsuperimposable mirror images (enantiomers) of selected organic compounds. However, before the advent of life, it is generally assumed that chemical reactions produced 50:50 (racemic) mixtures of enantiomers, as evidenced by common abiotic laboratory syntheses. Carbonaceous meteorites contain clues to prebiotic chemistry because they preserve a record of some of the Solar System’s earliest (˜4.5 Gy) chemical and physical processes. In multiple carbonaceous meteorites, we show that both rare and common sugar monoacids (aldonic acids) contain significant excesses of the d enantiomer, whereas other (comparable) sugar acids and sugar alcohols are racemic. Although the proposed origins of such excesses are still tentative, the findings imply that meteoritic compounds and/or the processes that operated on meteoritic precursors may have played an ancient role in the enantiomer composition of life’s carbohydrate-related biopolymers.

  12. Filamentous Trichomic Prokaryotes in Carbonaceous Meteorites: Indigenous Microfossils, Minerals, or Modern Bio-Contaminants?

    Science.gov (United States)

    Hoover, Richard B.; Rozanov, Alexei Yu.

    2011-01-01

    Large complex filaments have been detected in freshly fractured interior surfaces of a variety of carbonaceous meteorites. Many exhibit the detailed morphological and morphometric characteristics of known filamentous trichomic prokaryotic microorganisms. In this paper we review prior studies of filamentous microstructures encountered in the meteorites along with the elemental compositions and characteristics of the, fibrous evaporite minerals and filamentous cyanobacteria and homologous trichomic sulfur bacteria. The meteorite images and elemental compositions will compared with data obtained with the same instruments for abiotic microstructures and living and fossil microorganisms in order to evaluate the relative merits of the alternate hypotheses that have been advanced to explain the nature and characteristics of the meteorite filaments. The possibiility that the filaments found in the meteorites may be comprise modern bio-contaminants will be evaluated in light of their observed elemental compositions and data by other researchers on the detection of indigenous complex organic biosignatures, and extraterrestrial amino acids and nucleobases found in the Murchison CM2 and the Orgueil CI1 carbonaceous meteorites.

  13. Morphology, composition and mixing state of individual carbonaceous aerosol in urban Shanghai

    Directory of Open Access Journals (Sweden)

    H. Fu

    2011-07-01

    Full Text Available 834 individual aerosol particles were collected during Octoberober and Novemberember 2010 in urban Shanghai, China. Morphologies, compositions and mixing states of carbonaceous aerosols were investigated by transmission electron microscopy (TEM coupled with energy-dispersive X-ray (EDX. Structures of some particles were verified using selected-area electron diffraction (SAED. Among the aerosol particles observed, carbonaceous aerosols were categorized into five types: polymeric organic compound (POC, soot, tar ball, char, and biogenic particle. Based on the detailed TEM-EDX analysis, most of particles were coated with secondary organic aerosols (SOA, which commonly formed through condensation or heterogeneous reactions of precursor gases on pre-existing particles. The internally particles of sulphates, organics and soot were encountered frequently. Such internally mixed particles may be preferentially formed during a stagnated air mass which often occurred during serious pollution events, such as a haze episode on 13 Novemberember. Although relative number counts varied with different species, sulphates (38 %–71 % and soot (11 %–22 % constituted the most dominant species observed in the samples. With an exception of the sample collected during a dust storm on 12 Novemberember, soil-derived particles (68 % were relatively more frequently observed. Of particular interest was the biogenic particles encountered almost as frequently as soot on the sample collected on 13 November (18 % vs. 22 %. The result from air mass back-trajectory analysis indicated that these particles were marine-originated, most likely from the Yellow Sea.

  14. Role of air bubbles overlooked in the adsorption of perfluorooctanesulfonate on hydrophobic carbonaceous adsorbents.

    Science.gov (United States)

    Meng, Pingping; Deng, Shubo; Lu, Xinyu; Du, Ziwen; Wang, Bin; Huang, Jun; Wang, Yujue; Yu, Gang; Xing, Baoshan

    2014-12-01

    Hydrophobic interaction has been considered to be responsible for adsorption of perfluorooctanesulfonate (PFOS) on the surface of hydrophobic adsorbents, but the long C-F chain in PFOS is not only hydrophobic but also oleophobic. In this study, for the first time we propose that air bubbles on the surface of hydrophobic carbonaceous adsorbents play an important role in the adsorption of PFOS. The level of adsorption of PFOS on carbon nanotubes (CNTs), graphite (GI), graphene (GE), and powdered activated carbon (PAC) decreases after vacuum degassing. Vacuum degassing time and pressure significantly affect the removal of PFOS by these adsorbents. After vacuum degassing at 0.01 atm for 36 h, the extent of removal of PFOS by the pristine CNTs and GI decreases 79% and 74%, respectively, indicating the main contribution of air bubbles to PFOS adsorption. When the degassed solution is recontacted with air during the adsorption process, the removal of PFOS recovers to the value obtained without vacuum degassing, further verifying the key role of air bubbles in PFOS adsorption. By theoretical calculation, the distribution of PFOS in air bubbles on the adsorbent surfaces is discussed, and a new schematic sorption model of PFOS on carbonaceous adsorbents in the presence of air bubbles is proposed. The accumulation of PFOS at the interface of air bubbles on the adsorbents is primarily responsible for its adsorption, providing a new mechanistic insight into the transport, fate, and removal of PFOS. PMID:25365738

  15. Search for extinct natural radioactivity of Pb205 via thallium-isotope anomalies in chondrites and lunar soil.

    Science.gov (United States)

    Huey, J. M.; Kohman, T. P.

    1972-01-01

    Thallium and Pb204 contents were determined by stable-isotope-dilution analysis in 16 chondrites, one achondrite, and Apollo 11 and 12 lunar fines. Meteoritic thallium contents vary over a large range, 0.02 to 100 ppb, corresponding to the fact that thallium is a highly fractionated volatile element. Lunar thallium contents are less than 5 ppb. The Tl205/Tl203 ratio was determined in most of the samples, with precision ranging from 0.03% to several percent depending mainly on the amount of thallium present. No variations from the terrestrial ratio were observed. The chondritic isochron slope for Pb205 (13.8-m.y. half-life) is less than or equal to 0.00009 (99% confidence level), corresponding to an interval of at least 60 m.y. and possibly exceeding 120 m.y. between the termination of s-process nucleosynthesis and the lead-thallium fractionations.

  16. The comparison of element composition of Venus, Earth, Mars, and chondrites in the light of the Mendeleev Periodic Law

    International Nuclear Information System (INIS)

    The share of free neutral atoms, N0, for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrites and igneous rocks of the Earth on N0 was obtained. The Mendeleev Periodic Law was used to obtain the proof of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. To this end the concentration ratios of element-analogous with different N0 in the matters of Venus, Earth, Mars, and chondrites were compared. The data obtained are sufficient demonstration of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. With the account of the above said, it was shown that Shergotty and Tunguska meteorites by their relative elemental composition are close to Mars and asteroids, respectively. (author)

  17. Evidence for 26Al in Feldspars from the H4 Chondrite Ste. Marguerite

    Science.gov (United States)

    Zinner, E.; Gopel, C.

    1992-07-01

    One of the important questions for the history of the early solar system is whether or not there was enough ^26Al to melt small planetary bodies through the heat released by its decay. Although there is ample evidence for the existence of live ^26Al in refractory inclusions (Wasserburg and Papanastassiou, 1982; Hutcheon, 1982; Podosek et al., 1991), CAIs are special objects with peculiar properties and their Al is not necessarily representative of that of their host meteorites nor the early solar systems. Furthermore, some inclusions do not show any evidence for ^26Al (Wasserburg and Papanastassiou, 1982; Ireland, 1990; Virag et al., 1991), raising the possibility of ^26Al heterogeneity. The only previous observation of ^26Mg excesses attributed to the decay of ^26Al outside of CAIs was in an igneous clast from Semarkona (Hutcheon and Hutchison, 1989) leading to the conclusion that ^26Al indeed could have been a heat source for planetary melting. We have measured Al-Mg in plagioclase grains from the H4 chondrite Ste. Marguerite by ion microprobe mass spectrometry. Feldspars from H4 chondrites are good samples for addressing the problem of ^26Al as heat source because most Al resides in this phase and some H4s experienced fast cooling (Pellas and Storzer, 1981); in fact, the possibility of live ^26Al in feldspars from H4 chondrites that cooled fast has been predicted by Pellas and Storzer (1981). Furthermore, extremely precise absolute Pb/Pb ages exist for these meteorites (Gopel et al., 1991). Figure 1 shows the measurements on five feldspar crystals. All show ^26Mg excesses. A fit through the data points and the normal ^26Mg/^24Mg ratio of 0.13962 obtained from Lake County plagioclase measured under the same instrumental conditions as the Ste. Marguerite samples yields a (^26Al/^27Al)(sub)0 ratio of (2.0 +- 0.6) x 10^-7. If interpreted chronologically this ratio dates the retention of radiogenic ^26Mg in Ste. Marguerite feldspar to 5.6 +- 0.4 Ma after the

  18. Hydrogen and major element concentrations on 433 Eros: Evidence for an L- or LL-chondrite-like surface composition

    Science.gov (United States)

    Peplowski, Patrick N.; Bazell, David; Evans, Larry G.; Goldsten, John O.; Lawrence, David J.; Nittler, Larry R.

    2015-03-01

    A reanalysis of NEAR X-ray/gamma-ray spectrometer (XGRS) data provides robust evidence that the elemental composition of the near-Earth asteroid 433 Eros is consistent with the L and LL ordinary chondrites. These results facilitated the use of the gamma-ray measurements to produce the first in situ measurement of hydrogen concentrations on an asteroid. The measured value, 1100-700+1600 ppm, is consistent with hydrogen concentrations measured in L and LL chondrite meteorite falls. Gamma-ray derived abundances of hydrogen and potassium show no evidence for depletion of volatiles relative to ordinary chondrites, suggesting that the sulfur depletion observed in X-ray data is a surficial effect, consistent with a space-weathering origin. The newfound agreement between the X-ray, gamma-ray, and spectral data suggests that the NEAR landing site, a ponded regolith deposit, has an elemental composition that is indistinguishable from the mean surface. This observation argues against a pond formation process that segregates metals from silicates, and instead suggests that the differences observed in reflectance spectra between the ponds and bulk Eros are due to grain size differences resulting from granular sorting of ponded material.

  19. Micro-tomography and electron microscopy of a shock dike in the Buck Mountains 005 L6 chondrite

    Science.gov (United States)

    Brown, R.; Ruzicka, A. M.; Hutson, M.; Friedrich, J. M.; Rivers, M. L.

    2013-12-01

    Buck Mountains 005 is an L6 chondrite that contains a complexly structured shock dike. Scanning electron microscopy reveals that the dike consists of a holocrystalline, orthopyroxene-rich groundmass with a distinctive core-rim structure. Micro-tomography imaging shows that the dike is actually a sheet structure where the central sheet swells and pinches in a boudin-like fashion and is flanked by the rim. The central sheet entrains silicate clasts that were broken off and transported from the unmelted portion of the host. The flanking outer sheet is relatively clast free, but contains globules of metal with sulfides and bands of sheared, recrystallized Mg-olivine along the contact zone with the host. These two zones are separated by a thin band of sulfides with cellular metal that encloses euhedral silicate crystals. During dike formation, metal was mobilized and transported out of the dike and injected into the unmelted chondrite host, where it accumulated as larger grains. Formation of the dike can be attributed to localized shearing and heating that resulted in simple cataclasis and melting. The melt underwent FeO reduction and vaporization of volatile alkali elements, followed by rapid igneous crystallization. The combination of these processes transformed the mineralogy of the original chondrite, making it poorer in olivine and feldspar and richer in pyroxene. The Buck Mountain 005 dike presents further insight into the importance of shock in meteorites.

  20. A Deep Moho in "Small Planet" Vesta and Implication Regarding the Chondritic Nature of Protoplanets

    Science.gov (United States)

    Clenet, H.; Jutzi, M.; Barrat, J. A.; Asphaug, E. I.; Benz, W.; Gillet, P.

    2014-12-01

    Asteroid 4-Vesta is the only differentiated protoplanet [1] which has been extensively explored by a space probe, and is represented by a large collection of basaltic and ultramafic samples, the Howardite-Eucrite-Diogenite (HED) meteorites. High-resolution global mapping by the Dawn probe revealed that the south polar depression is composed of two overlapping impact basins, Veneneia and Rheasilvia [2]. Numerical simulations taking into account both sequential events [3] show that surface material in the northern hemisphere of Vesta came from a depth of about 20 km, whereas the exposed southern material comes from a depth of 60 to 100 km. Recent magma-ocean crystallization models [4], which consider a chondritic initial composition, predict a crustal thickness of 30-40 km. Thus a succession of two impacts would have dug well into the olivine-rich mantle. Here we use the results from 3D smooth particle hydrodynamics impact simulations to show that, not only the floor of the basins should expose very deep lithologies, but that a significant proportion of the rocks which have escaped from Vesta during the second impact originated from depth much greater than 40 km. We also mapped locally Vesta's mineralogy with images from the Dawn VIR spectrometer. The lack of olivine-rich lithologies in the Veneneia/Rheasilvia region, and the simultaneous lack of mantle samples among the vestoids and HEDs together provide evidence that the crust-mantle boundary (or Moho) was not reached during the two impacts, and entails that Vesta's Moho is deeper than 80 km [5]. With a deep Moho, it appears clear that the mantle is much thinner than expected, leading to the conclusion that Vesta contains far less olivine than predicted by magma-ocean crystallization models. This could be an evidence that its bulk chemical composition deviates substantially from a chondritic composition for major elements, alike as for sodium and other volatiles. [1] Russell et al, Science 336, 684-686, 2012

  1. Earth's Uranium and Thorium content and geoneutrinos fluxes based on enstatite chondrites

    Science.gov (United States)

    Javoy, Marc; Kaminski, Edouard

    2014-12-01

    The Earth's thermal evolution is controlled by the amount of heat released by the radioactive decay of 40K, 238U, 235U and 232Th. Their crust and upper mantle content is inferred from direct sampling, whereas estimating the lower mantle concentrations requires indirect constraints, such as those brought by primitive chondrites, or by geoneutrinos. Here we follow the framework of "E-Earth" models, based on the isotopic and chemical composition of E-chondrites (EC), to calculate U and Th concentrations in the Earth's present day mantle, and the corresponding geoneutrinos flux. The model uses a compilation of data of U and Th contents of EC and account for the Earth differentiation and crust extraction. We obtain that the Bulk Silicate Earth (BSE) contains 15.4±1.8 ppb of Uranium and 51.3±4.4 ppb of Thorium, and has an average Th/U mass ratio of 3.4±0.4, with a peak value around 3.15. The prediction of geoneutrinos events originating from the mantle (i.e., without taking into account the local contribution of the crust) is 5.1±1.0 TNU, with 4.3±0.9 TNU coming from Uranium, and 0.8±0.2 TNU from Thorium. These numbers are in good agreement with the most recent KamLAND detector estimate, and compatible with the (higher) Borexino flux. On the other hand, the KamLAND constraints are not consistent with the high content of heat producing elements in the mantle predicted by the simple application of parameterized convection model to the thermal evolution of the Earth's mantle. Since the measurement error in the mantle neutrino flux is currently dominated by the crustal contribution, geoneutrinos cannot for now discriminate between CI-based and EH-base models of the Earth's composition. Further progress is expected if an ocean based geoneutrino detector is deployed.

  2. The Anatomy and Bulk Composition of CAI Rims in the Vigarano (CV3) Chondrite

    Science.gov (United States)

    Ruzicka, A.; Boynton, W. V.

    1993-07-01

    A striking feature of Ca,Al-rich inclusions (CAIs) in chondrites is the presence of mineralogical layers that typically form rim sequences up to 50 micrometers thick [1]. Many ideas regarding the origin of CAI rims have been proposed, but none are entirely satisfactory. The detailed mineralogy and bulk compositions of relatively unaltered CAI rims in the Vigarano (CV3) chondrite described here provide constraints on hypotheses of rim formation. Rim Mineralogy: CAIs in Vigarano consist of melilite (mel)- and spinel (sp)- rich varieties, both of which are rimmed [2]. Around mel-rich objects, the layer sequence is CAI interior --> sp-rich layer (sometimes absent) --> mel/anorthite (anor) layer --> Ti-Al-rich clinopyroxene (Tpx) layer --> Al- diopside (Al-diop) layer --> olivine (ol) +/- Al-diop layer --> host matrix. The sequence around sp-rich objects differs from this in that the mel/anor layer is absent. Both the sp-rich layer around mel-cored CAIs and the cores of sp-rich CAIs in Vigarano are largely comprised of a fine-grained (anor layer is sometimes monomineralic, consisting of mel alone, or bimineralic, consisting of both mel and anor. Where bimineralic, anor typically occurs in the outer part of the layer. In places, anor (An(sub)99-100) has partially altered to nepheline and voids. Rim mel is systematically less gehlenitic than mel in the CAI interiors, especially compared to mel in the interior adjacent to the rims. The Tpx layer (>2 and up to 15 wt% TiO2) and Al-diop layer ( sp + fo --> sp + fo + anor or mel or Tpx) that does not correspond to observed rim sequences. It thus appears that (1) the rim region did not form through crystallization of molten CAIs; and (2) rim layers did not originate solely by the crystallization of a melt layer present on a solid CAI core [4,5]. References: [1] Wark D. A. and Lovering J. F. (1977) Proc. LSC 8th, 95-112. [2] Ruzicka A. and Boynton W. V. (1991) Meteoritics, 26, 390-391. [3] Stolper E. (1982) GCA, 46, 2159

  3. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    Science.gov (United States)

    Lacey, Forrest; Henze, Daven

    2015-11-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  4. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    International Nuclear Information System (INIS)

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  5. Seasonal variation of urban carbonaceous aerosols in a typical city Nanjing in Yangtze River Delta, China

    Science.gov (United States)

    Li, Bing; Zhang, Jie; Zhao, Yu; Yuan, Siyu; Zhao, Qiuyue; Shen, Guofeng; Wu, Haisuo

    2015-04-01

    The Yangtze River Delta (YRD) is one of the regions with the most dynamic economy and severe atmospheric pollution in China. In order to characterize the particle features, especially the carbonaceous component in the YRD, particulate matter smaller than 2.5 μm (PM2.5) and 10 μm (PM10) samples in each season were collected in urban Nanjing, a typical city that locates in the west part of the YRD. The organic carbon (OC) and elemental carbon (EC) was differentiated using the thermal optical reflectance method. The average concentrations of PM2.5, OC and EC during the study periods were observed to be 117.6, 13.8, and 5.3 μg/m3 respectively, with all the highest levels in winter. The mass fraction of the Total carbonaceous aerosol (TCA) in PM2.5 was estimated at 23% on average, lower than those reported for other cities in the YRD. The OC and EC correlated well in all the seasons, especially in spring and winter, implying that OC and EC were attributed to common emission sources. Good correlation was observed between OC and estimated K+ from biomass burning in the harvest season in autumn and summer, indicating biomass burning a significant source of carbonaceous aerosols. This could also be confirmed by the lower fraction of OC3 + OC4 in OC during autumn and summer. The secondary organic carbon (SOC) estimated by EC-tracer method was the highest in winter (7.3 μg/m3) followed by autumn (6.7 μg/m3), summer (3.7 μg/m3) and spring (2.0 μg/m3). However, the SOC/OC in winter was not as high as that in summer and autumn, implying the high concentration of OC in winter was probably due to the stable weather but not mainly caused by SOC formation. The high SOC/OC ratio in summer was attributed to stronger oxidation, which could be suggested by higher sulfur oxidation ratio (SOR).

  6. Source apportionment of the summer time carbonaceous aerosol at Nordic rural background sites

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2011-12-01

    Full Text Available In the present study, natural and anthropogenic sources of particulate organic carbon (OCp and elemental carbon (EC have been quantified based on weekly filter samples of PM10 (particles with aerodynamic diameter <10 μm collected at four Nordic rural background sites [Birkenes (Norway, Hyytiälä (Finland, Vavihill (Sweden, Lille Valby, (Denmark] during late summer (5 August–2 September 2009. Levels of source specific tracers, i.e. cellulose, levoglucosan, mannitol and the 14C/12C ratio of total carbon (TC, have been used as input for source apportionment of the carbonaceous aerosol, whereas Latin Hypercube Sampling (LHS was used to statistically treat the multitude of possible combinations resulting from this approach. The carbonaceous aerosol (here: TCp; i.e. particulate TC was totally dominated by natural sources (69–86%, with biogenic secondary organic aerosol (BSOA being the single most important source (48–57%. Interestingly, primary biological aerosol particles (PBAP were the second most important source (20–32%. The anthropogenic contribution was mainly attributed to fossil fuel sources (OCff and ECff (10–24%, whereas no more than 3–7% was explained by combustion of biomass (OCbb and ECbb in this late summer campaign i.e. emissions from residential wood burning and/or wild/agricultural fires. Fossil fuel sources totally dominated the ambient EC loading, which accounted for 4–12% of TCp, whereas <1.5% of EC was attributed to combustion of biomass. The carbonaceous aerosol source apportionment showed only minor variation between the four selected sites. However, Hyytiälä and Birkenes showed greater resemblance to each other, as did Lille Valby and Vavihill, the two latter being somewhat more influenced by anthropogenic sources. Ambient levels of organosulphates and nitrooxy-organosulphates in the Nordic rural

  7. Source apportionment of the summer time carbonaceous aerosol at Nordic rural background sites

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2011-06-01

    Full Text Available In the present study, natural and anthropogenic sources of particulate organic carbon (OCp and elemental carbon (EC have been quantified based on weekly filter samples of PM10 collected at four Nordic rural background sites (Birkenes (Norway, Hyytiälä (Finland Vavihill (Sweden, Lille Valby (Denmark during late summer (5 August–2 September 2009. Levels of source specific tracers, i.e. cellulose, levoglucosan, mannitol and the 14C/12C ratio of total carbon (TC, have been used as input for source apportionment of the carbonaceous aerosol, whereas Latin Hypercube Sampling (LHS was used to statistically treat the multitude of possible combinations resulting from this approach.

    The carbonaceous aerosol (here: TCp; i.e. particulate TC was totally dominated by natural sources (69–86 %, with biogenic secondary organic aerosol (BSOA being the single most important source (48–57 %. Interestingly, primary biological aerosol particles (PBAP were the second most important source (20–32 %. The anthropogenic contribution was mainly attributed to fossil fuel sources (OCff and ECff (10–24 %, whereas no more than 3–7 % was explained by combustion of biomass (OCbb and ECbb in this late summer campaign i.e. emissions from residential wood burning and/or wild/agricultural fires. Fossil fuel sources totally dominated the ambient EC loading, accounting for 4–12 % of TCp, whereas <1.5 % was attributed to combustion of biomass. The carbonaceous aerosol source apportionment showed only minor variation between the four selected sites. However, Hyytiälä and Birkenes showed greater resemblance to each other, as did Lille Valby and Vavihill, the two latter being somewhat more influenced by anthropogenic sources.

    Ambient levels of organosulphates and nitrooxy-organosulphates in the Nordic rural background environment are reported for

  8. Carbonaceous aerosols and pollutants over Delhi urban environment: Temporal evolution, source apportionment and radiative forcing.

    Science.gov (United States)

    Bisht, D S; Dumka, U C; Kaskaoutis, D G; Pipal, A S; Srivastava, A K; Soni, V K; Attri, S D; Sateesh, M; Tiwari, S

    2015-07-15

    Particulate matter (PM2.5) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO4(2-) and NO3(-)) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM2.5 samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO4(2-) and NO3(-)). Furthermore, continuous (online) measurements of PM2.5 (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM2.5 (online) range from 18.2 to 500.6μgm(-3) (annual mean of 124.6±87.9μgm(-3)) exhibiting higher night-time (129.4μgm(-3)) than daytime (103.8μgm(-3)) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO3(-)and SO4(2-), which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R(2)=0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~1.8-2.0Kday(-1)) due to agricultural burning effects during the 2012 post-monsoon season. PMID:25864155

  9. Characteristics of carbonaceous aerosols at a pair of suburban and downtown sites in Nanjing, China

    Science.gov (United States)

    Cui, H.; Zhang, J.; Zhao, Y.

    2014-12-01

    Carbonaceous species in PM2.5 were measured in three seasons (except winter) in downtown and around a year in suburban in Nanjing. In particular, the OC and EC concentrations were continuously measured with 1-h interval at both sites. The mean concentrations of PM2.5, OC, EC were 85.9 μg/m3, 10.4 μg/m3, 4.2 μg/m3 and 63.4 μg/m3, 8.1 μg/m3, 5.3μg/m3 for downtown and suburban respectively. At the suburban site, compared to the lowest average concentration in spring, the relatively higher concentration of carbonaceous aerosol in summer was caused by biomass-burning activities. Significant increasing peaks of OC (up to 122.9 ug/m3) and EC (up to 35.8 ug/m3) in suburban were recorded in the June 10th night, and it is indicated using back trajectory that the air mass came through nearby agriculture areas. On the other hand, the OC and EC concentrations during the 2nd AYG (Asian Youth Games, Aug 16th - 24th in 2013) compared to that in rest days in August reduced by 21% and 10%, respectively, attributing to the effective control measures on reduction of industrial point sources, temporary control of motor vehicle and fugitive dusts. Rations of OC/EC in suburban were much lower than that in downtown. This might be due to the fact that the sampling point in suburban is quite close (in 400 meters) to a main highway. Both OC and EC concentrations in suburban were higher in nighttime than daytime, except OC in summer, indicating the existence of strong SOC and supported by high OC/EC and O3 at noon. The annual average SOC estimated by EC-tracer methods occupied 34.5% and 36.7% of the total OC for the downtown and suburban areas, respectively. OC/EC correlations in suburban were much weaker than those from downtown areas, which shows suburban areas is much more affected by long-range transport of pollution and/or complex sources including domestic coal combustion, biomass burning, industrial and transportation, especially in three other seasons except winter, which is

  10. Variations in carbonaceous species at a high-altitude site in western India: Role of synoptic scale transport

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, Ashwini; KirpaRam; Ojha, N.

    Atmospheric fine-mode particulate matter (PM2.5), collected during January to December 2007 at a high-altitude site (Mt. Abu, 24.6°N, 72.7°E, 1680 m asl) in the western India, have been analysed for carbonaceous and inorganic species to assess...

  11. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris) during the Megapoli summer and winter campaigns

    NARCIS (Netherlands)

    Fountoukis, C.; Megaritis, A.G.; Skyllakou, K.; Charalampidis, P.E.; Denier van der Gon, H.A.C.; Crippa, M.; Prevot, A.S.H.; Fachinger, F.; Wiedensohler, A.; Pilinis, C.; Pandis, S.N.

    2016-01-01

    We use a three-dimensional regional chemical transport model (PMCAMx) with high grid resolution and high-resolution emissions (4 x 4 km2) over the Paris greater area to simulate the formation of carbonaceous aerosol dur-ing a summer (July 2009) and a winter (January/February 2010) period as part of

  12. Effects of day-of-week trends and vehicle types on PM2.5-bounded carbonaceous compositions

    International Nuclear Information System (INIS)

    Carbonaceous compositions of PM2.5 were measured in the heart of Bangkok from 17th November 2010 to 19th January 2012, and a data set of 94 samples was constructed. Effects of day-of-week trends and vehicle types on PM2.5-bound TC, OC, and EC were carefully investigated. In this study, OC was the most important contributor to the total PM2.5 mass concentration. The average PM2.5-bound OC content measured at CHAOS (18.8 ± 9.18 μg m−3) was approximately 11 times higher than at Chaumont, Switzerland (1.7 μg m−3), but approximately five times lower than at Xi'an, China (93.0 μg m−3). The application of diagnostic binary ratios of OC/EC and estimations of secondary organic carbon (SOC) coupled with autocorrelation plots (Box and Jenkins) highlight the enhanced impacts of traffic emissions, especially from diesel vehicles, on PM2.5-bound carbonaceous compositions on weekdays relative to weekends. Hierarchical cluster analysis (HCA) coupled with principal component analysis (PCA) underline the importance of diesel emissions as the primary contributors of carbonaceous aerosols, particularly during weekdays. - Highlights: • Traffic emissions play an important role in governing OC and EC during weekdays. • Time series analysis shows the existence of day-of-week trends of OC and EC. • Diesel vehicles are the main contributors of carbonaceous compositions

  13. Carbonaceous PM2.5 emitted from light-duty vehicles operating on low-level ethanol fuel blends.

    Science.gov (United States)

    This study aims to examine carbonaceous aerosol emissions from three Tier 2-certified 2008 model year LDVs burning e0, e10, and e85 fuel blends at -7°C and 24°C. The LDVs were tested on an electric chasis dynamometer using the LA-92 Urban Driving Cycle (UDC). Exhaust was ...

  14. Sustainable and scalable production of monodisperse and highly uniform colloidal carbonaceous spheres using sodium polyacrylate as the dispersant.

    Science.gov (United States)

    Gong, Yutong; Xie, Lei; Li, Haoran; Wang, Yong

    2014-10-28

    Monodisperse, uniform colloidal carbonaceous spheres were fabricated by the hydrothermal treatment of glucose with the help of a tiny amount of sodium polyacrylate (PAANa). This synthetic strategy is effective at high glucose concentration and for scale-up experiments. The sphere size can be easily tuned by the reaction time, temperature and glucose concentration. PMID:25199065

  15. Petrology of the Baszkowka L5 chondrite: A record of surface-forming processes on the parent body

    Science.gov (United States)

    Przylibski, T. A.; Pilski, A. S.; Zagożdżon, P. P.; Kryza, R.

    2003-06-01

    We review the petrology of Baszkowka, present new microprobe data on mineral constituents, and propose a model for surface properties of the parent body consistent with these data. The low shock index and high porosity of the Baszkowka L5 chondrite mean that considerable primary textural and petrographic detail is preserved, allowing insight into the structure and evolution of the parent body. This meteorite formed in a sedimentary environment resembling that in which pyroclastic rocks are deposited. The origin of the component chondrules, achondritic fragments (mostly olivine and pyroxene aggregates), chondritic-achondritic aggregates, and compound chondrules can be explained by invoking collision of 2 melted or partially melted planetesimals, each covered with a thin crust. This could have happened at an early stage in the evolution of the solar system, between 1 and 2 Myr after its origin. The collision resulted in the formation of a cloud containing products of earlier magmatic crystallization (chondrite and achondrite fragments) from which new chondrules were created. Particle collision in this cloud produced fragmented chondrules, chondritic-achondritic aggregates, and compound chondrules. Within this low-density medium, these particles were accreted on the surface of the larger of the planetesimals involved in the collision. The density of the medium was low enough to prevent grain-size sorting of the components but high enough to prevent the total loss of heat and to enable the welding of fragments on the surface of the body. The rock material was homogenized within the cloud and, in particular, within the zone close to the planetesimal surface. The hot material settled on the surface and became welded as molten or plastic metal, and sulfide components cemented the grains together. The process resembled the formation of welded ignimbrites. Once these processes on the planetesimal surface were completed, no subsequent recrystallization occurred. The high

  16. Hydrogen Isotopes of Glassy and Phyllosilicate Spherules in Al Rais (CR) and Orgueil (CI) Chondrites

    Institute of Scientific and Technical Information of China (English)

    GUAN Yunbin; Michael E. ZOLENSKY

    2004-01-01

    The hydroxyl in phyllosilicate minerals is the most common occurrence of water in primitive meteorites.Direct hydrogen isotopic analysis of this water component using an ion microprobe has been made in some glassy or phyllosilicate spherules from the Al Rais (CR) and Orgueil (CI) chondrites. The spherules from Al Rais show large deuterium excesses (δD = +200 - +800) relative to terrestrial standards, whereas deuterium-enrichments in the spherules from Orgueil are much smaller (δD = +40 - +130‰). The phyllosilicate spherules are products of aqueous alteration of glassy precursors. In A1 Rais the phyllosilicate spherules have relatively higher δD values than the glassy ones, indicating that water introduced during aqueous alteration was deuterium-enriched. The deuterium-enrichments in the phyllosilicate spherules from Orgueil could result from isotopic exchange under thermodynamic conditions within the solar nebula. The much larger δD excesses of the Al Rais spherules, however, cannot be attributed to the similar process;instead, an interstellar origin needs to be invoked.

  17. The natural thermoluminescence of meteorites. 7: Ordinary chondrites from the Elephant Moraine region, Antarctica

    Science.gov (United States)

    Benoit, P. H.; Roth, J.; Sears, H.; Sears, D. W. G.

    1994-01-01

    We report natural and induced thermoluminescence (TL) measurements for meteorites from the Elephant Moraine region (76 deg 17 min S, 157 deg 20 min E) of Antarctica. We use our data to identify fragmented meteorites (i.e., 'pairings'); our dataset of 107 samples represents at most 73 separate meteorite falls. Pairing groups are generally confined to single icefields, or to adjacent icefields, but a small proportion cross widely separated icefields in the region, suggesting that the fields can be considered as a single unit. Meteorites from this region have high natural TL levels, which indicates that they have small terrestrial surface exposure ages (less than 12,500 years). There do not appear to be significant differences in natural TL levels (and hence surface exposure ages) between individual blue icefields in the region. The proportion of reheated meteorites from the Elephant Moraine region is similar to that of other Antarctic sites and modern falls, consistent with the uniformity of the meteoritic flux in this regard. An unusual subset of H-chondrites, with high induced TL peak temperatures, is absent among the data for meteorites collected in the Elephant Moraine region, which stresses their similarity to modern falls. We suggest that the Elephant Moraine region, which stresses their similarity to modern falls. We suggest that the Elephant Moraine icefields formed through shallow ablation of the ice. Unlike the Allan Hills sites to the south, lateral transport is probably less important relative to the infall of meteorites in concentrating meteorites on these icefields.

  18. A Search for Subkilometer-sized Ordinary Chondrite Like Asteroids in the Main-Belt

    CERN Document Server

    Lin, H W; Chen, Y T; Ip, W H; Chang, C K

    2015-01-01

    The size-dependent effects of asteroids on surface regolith and collisional lifetimes suggest that small asteroids are younger than large asteroids. In this study, we performed multicolor main-belt asteroid (MBA) survey by Subaru telescope/Suprime-Cam to search for subkilometer-sized ordinary chondrite (Q-type) like MBAs. The total survey area was 1.5 deg^2 near ecliptic plane and close to the opposition. We detected 150 MBAs with 4 bands (B, V , R, I) in this survey. The range of absolute magnitude of detected asteroids was between 13 and 22 magnitude, which is equivalent to the size range of kilometer to sub-kilometer diameter in MBAs. From this observation, 75 of 150 MBAs with color uncertainty less than 0.1 were used in the spectral type analysis, and two possible Q-type aster- oids were detected. This mean that the Q-type to S-type ratio in MBAs is < 0.05. Meanwhile, the Q/S ratio in near Earth asteroids (NEAs) has been estimated to be 0.5 to 2 (Binzel et al., 2004; Dandy et al., 2003). Therefore, Q-t...

  19. Hibonite, Ca2/Al, Ti/24O38, from the Leoville and Allende chondritic meteorites.

    Science.gov (United States)

    Keil, K.; Fuchs, L. H.

    1971-01-01

    Hibonite was discovered in light-colored, Ca-Al-Ti-rich and Si-Fe-poor, achondritic inclusions of the Leoville and Allende HL-group chondrites. Two varieties of hibonite occur: one emits a bright red-orange luminescence under electron bombardment and has high amounts of Al2O3 (87.7; 87.9) and low amounts of MgO (0.65; 0.8) and TiO2 (0.68; 0.8). The other emits a bright blue luminescence and is low in Al2O3 (78.7; 79.2) and high in MgO (3.3; 3.7) and TiO2 (6.5; 7.9) (in wt. %). The oxide CaO is about the same in both varieties. It is suggested that the change in the color of the visible luminescence results from changes in composition. The origin of hibonite which occurs in complex mineral assemblages together with anorthite, gelhenite, wollastonite, aluminous diopside, andradite, Ca-pyroxene, perovskite, spinel, taenite, chromite, and pentlandite, and in close proximity to nodules containing calcite, whewellite, forsterite and many of the aforementioned phases, is discussed. The proposition that hibonite and associated phases originated by contact metamorphism and metasomatism of calcite-dolomite bearing assemblages cannot, at this time, be completely ruled out.

  20. Photoluminescence of silicon-vacancy defects in nanodiamonds of different chondrites

    CERN Document Server

    Shiryaev, A A; Semjonova, L F; Khomich, A A; Vlasov, I I

    2015-01-01

    Photoluminescence spectra show that silicon impurity is present in lattice of some nanodiamond grains (ND) of various chondrites as a silicon-vacancy (SiV) defect. The relative intensity of the SiV band in the diamond-rich separates depends on chemical composition of meteorites and on size of ND grains. The strongest signal is found for the size separates enriched in small grains; thus confirming our earlier conclusion that the SiV defects preferentially reside in the smallest (less than 2 nm) grains. The difference in relative intensities of the SiV luminescence in the diamond-rich separates of individual meteorites are due to variable conditions of thermal metamorphism of their parent bodies and/or uneven sampling of nanodiamonds populations. Annealing of separates in air eliminates surface sp2-carbon, consequently, the SiV luminescence is enhanced. Strong and well-defined luminescence and absorption of the SiV defect is a promising feature to locate cold (< 250 {\\deg}C) nanodiamonds in space.