WorldWideScience

Sample records for cosmochemistry

  1. Cosmochemistry and Human Exploration

    Science.gov (United States)

    Taylor, G. J.

    2004-12-01

    About 125 scientists, engineers, business men and women, and other specialists attended the sixth meeting of the Space Resources Roundtable, held at the Colorado School of Mines in Golden, Colorado. The meeting was co-sponsored by the Space Resources Roundtable, Inc. (a nonprofit organization dedicated to the use of space resources for the benefit of humankind), the Lunar and Planetary Institute, and the Colorado School of Mines. Presentations and discussions during the meeting made it clear that the knowledge gained from cosmochemical studies of the Moon and Mars is central to devising ways to use in situ resources. This makes cosmochemistry central to the human exploration and development of space, which cannot happen without extensive in situ resource utilization (ISRU). Cosmochemists at the meeting reported on an array of topics: the nature of lunar surface materials and our lack of knowledge about surface materials in permanently shadowed regions at the lunar poles; how to make reasonable simulated lunar materials for resource extraction testbeds, vehicle design tests, and construction experiments on Earth; and how to explore for resources on the Moon and Mars.

  2. Some applications of SIMS in conservation science, archaeometry and cosmochemistry

    International Nuclear Information System (INIS)

    McPhail, D.S.

    2006-01-01

    Some applications of SIMS in conservation science, archaeometry and cosmochemistry are described. Ultra-low energy SIMS depth profiling and TOF-SIMS imaging are used to study the corrosion of low-lime glass vessels from the V and A museum. Static SIMS and focused ion beam (FIB) SIMS are used to study the effects of laser cleaning on museum artefacts. Archaeological glass from Raqqa, Syria is studied with FIB-SIMS and micrometeorite impacts on space vessels are studied with FIB and FIB-SIMS. The new analytical challenges provided to the SIMS community by these materials are presented and the ethical issues associated with sampling and destructive analysis discussed

  3. Harold Urey, Deuterium, Cosmochemistry, Studies of the Origin of Life, and

    Science.gov (United States)

    , Cosmochemistry, Studies of the Origin of Life, and Theory of Earth's Evolution Resources with Additional in WWII. ... After 1950 his interests turned to the chemistry of the planets, and he is credited with had enormous influence in subsequent research on the origin of life.'3 'In a long and varied career

  4. Determination of trace elements: Neutron-activation analysis in geochemistry and cosmochemistry

    International Nuclear Information System (INIS)

    Kolesov, G.M.

    1994-01-01

    Geochemistry, like cosmochemistry, open-quotes studies chemical elements hor-ellipsis of the crust and hor-ellipsis the Earth hor-ellipsis their history, their distribution hor-ellipsis their genetic hor-ellipsis connectionsclose quotes and is based on data on the abundance and distribution of elements obtained by various analytical methods. Neutron-activation analysis (NAA) plays a particular role in this respect. This is due to its high sensitivity (detection limit as small as 10 -14 g), which makes possible the use of samples of arbitrary mass, and also due to the possibility of obtaining information about composition without destruction of the object, conserving, if required, the unique material under investigation. Of the most interest are the data on the contents for a number of trace elements (at a level of 10 -7 - 10 -4 %), among which are rare-earth elements (REE), U, Th, Zr, Hf, Ta, W, Ga, Ni, Rb, Cs, platinum-group metals, Ag, Au, etc. These elements are considered as indicators of geochemical processes associated with the genesis and evolution of solar system bodies in early and more recent stages of evolution; they are also used to study processes and phenomena at zone boundaries: river-sea, ocean-atmosphere, and so on. The aim of this work is to show the capabilities of NAA in the determination of trace elements

  5. High pressure cosmochemistry of major planetary interiors: Laboratory studies of the water-rich region of the system ammonia-water

    Science.gov (United States)

    Nicol, Malcolm; Johnson, Mary; Boone, Steven; Cynn, Hyunchee

    1987-01-01

    Several studies relative to high pressure cosmochemistry of major planetary interiors are summarized. The behavior of gas-ice mixtures at very high pressures, studies of the phase diagram of (NH3) sub x (H2O) sub 1-x at pressures to 5GPa and temperatures from 240 to 370 K, single crystal growth of ammonia dihydrate at room temperature in order to determine their structures by x-ray diffraction, spectroscopy of chemical reactions during shock compression in order to evaluate how the reactions affect the interpretation of equation of state data obtained by shock methods, and temperature and x-ray diffraction measurements made on resistively heated wire in diamond anvil cells in order to obtain phase and structural data relevant to the interiors of terrestrial planets are among the studies discussed.

  6. Geo- and cosmochemistry and archaeology

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Lunar samples were analyzed by fast-neutron, slow-neutron, and photon-activation for F, Cl, Br, I, U, Li, Te, Hg, Ru, Os, 204 Pb, Bi, Tl, and Zn. In mineralogical studies, the distribution of U, Th, Ba, and the rare earths in the calcium--aluminium-rich inclusions in the Allende meteorite was studied by analyzing 15 Allende inclusions using neutron activation methods. (U.S.)

  7. Mass spectrometric researches in isotope cosmochemistry

    International Nuclear Information System (INIS)

    Gopalan, K.

    1979-01-01

    Recent advances in the understanding of solar system processes, past and present, based on mass spectrometric researches on meteorites and moon samples are reviewed. The topics include the following : (1) Duration of nebular condensation, (2) Terminal stages of nucleosynthesis, (3) Planetary formation and evolution, (4) Heterogeneities in the solar nebula and (5) Solar wind composition. (auth.)

  8. Applications of the ion microprobe to geochemistry and cosmochemistry

    International Nuclear Information System (INIS)

    Shimizu, N.; Hart, S.R.

    1982-01-01

    When a solid surface is subjected to a bombardment of energetic ions, material is ejected from the surface in a process known as sputtering. A part of the sputtered material is ionized and these secondary ions can be analyzed with a mass spectrometer according to a technique known as secondary ion mass spectrometry (SIMS). A description is presented of the present status of geochemical and cosmochemical applications of the ion microprobe. Attention is given to the sputtering event, molecular ion interferences, aspects of isotopic fractionation, secondary ion intensities in polycomponent materials, and questions of trace element analysis. Geochemical applications of the ion microprobe are based on certain advantages over other analytical techniques. These advantages are related to high sensitivity, low background, and the capability of in situ analysis of isotopic composition. The distribution of trace elements in minerals is considered, along with isotope anomalies, isotope zoning, diffusion studies, and depth profiling

  9. The Cosmochemistry of Pluto: A Primordial Origin of Volatiles?

    Science.gov (United States)

    Glein, C. R.; Waite, J. H., Jr.

    2017-12-01

    Pluto is a wonderland of volatiles. Nitrogen, methane, and carbon monoxide are the principal volatiles that maintain its tenuous atmosphere, and they have also created a mesmerizing landscape of icy geological features, including Pluto's iconic "heart". Recent data, particularly those returned by the New Horizons mission [1-3], allow us to begin testing hypotheses for the cosmochemical origins of these world-shaping species on Pluto. Here, we investigate if Pluto's volatiles could have been accreted in its building blocks. We take both bottom-up and top-down approaches in testing this hypothesis in terms of mass balance. We estimate Pluto's primordial inventory of volatiles by scaling a range of cometary abundances up to the ice mass fraction of Pluto. We also make estimates of the present and lost inventories of volatiles based on surface observations and interpretations, as well as different scenarios of atmospheric photochemistry and escape. We find that, if primordial Pluto resembled a giant comet with respect to volatile abundances, then the initial volatile inventory would have been sufficient to account for the estimated present and lost inventories. This consistency supports a primordial origin for Pluto's volatiles. However, the observed ratio of CO/N2 in Pluto's atmosphere [4] is several orders of magnitude lower than the nominal cometary value. We are currently using phase equilibrium and rate models to explore if volatile layering in Sputnik Planitia, or the destruction of CO in a past or present subsurface ocean of liquid water could explain the apparent depletion of CO on Pluto. References: [1] Moore et al. (2016) Science 351, 1284. [2] Grundy et al. (2016) Science 351, aad9189. [3] Gladstone et al. (2016) Science 351, aad8866. [4] Lellouch et al. (2017) Icarus 286, 289.

  10. High pressure cosmochemistry applied to major planetary interiors: Experimental studies. [phase diagram for the ammonia water system

    Science.gov (United States)

    Nicol, M. F.; Johnson, M.; Schwake, A.

    1983-01-01

    Progress is reported in the development of the P-T-X diagram for 0 less than or = X less than or = 0.50 and in the development of techniques for measuring adiabats of phases of NH3-H2O. The partial phase diagram is presented, investigations of the compositions of ammonia ices are described, and methods for obtaining the infrared spectra of ices are discussed.

  11. Cosmic-ray production of tungsten isotopes in lunar samples and meteorites and its implications for Hf-W cosmochemistry

    Science.gov (United States)

    Leya, Ingo; Wieler, Rainer; Halliday, Alex N.

    2000-01-01

    Excesses and deficiencies in 182W in meteorites and lunar samples relative to the terrestrial 182W atomic abundance have been assigned to the decay of 182Hf (t1/2=9 Ma) and have been used to date metal-silicate fractionation events in the early solar system. Because the effects are very small, production and burn-out of tungsten isotopes by cosmic ray interactions are a concern in such studies. Masarik [J. Masarik, Contribution of neutron-capture reactions to observed tungsten isotopic ratios, Earth Planet. Sci. Lett. 152 (1997) 181-185] showed that neutron-capture reactions on tungsten isotopes can account at best for a minor part of the observed deficit of 182W in Toluca and other iron meteorites. On the other hand, in lunar samples and stony meteorites the production of 182W from 181Ta may become crucial. Here, we calculate this contribution as well as production and consumption of 182-186W by other neutron-induced reactions. The neutron fluence of each sample is estimated by its nominal cosmic-ray exposure age deduced from noble gas data. This approach overestimates the true cosmogenic W isotopic shifts for samples that might have been irradiated very close to the regolith surface. A quantitative estimate is often also hampered by a lack of Ta data. Despite these reservations, it appears that in many lunar samples neutron-capture on Ta has caused a large part of the observed 182W excess. On the other hand, in some samples, especially those with very low exposure ages, clearly only a minor or even negligible fraction of the 182W excess can be cosmogenic. Therefore, the conclusion, based on Hf-W model ages, that the Moon formed 50 Myr after the start of the solar system remains valid. Martian meteorites have lower Ta/W ratios and cosmic ray exposure ages than most lunar samples. Therefore, cosmogenic production has not significantly altered the W isotopic composition in Martian meteorites. Observed 182W excesses in Martian meteorites as well as the very large excesses in two eucrites are undoubtedly the result of early 182Hf decay.

  12. Kodai School on ‘Synthesis of Elements in Stars’

    CERN Document Server

    Goswami, Aruna; Principles and Perspectives in Cosmochemistry

    2010-01-01

    A fundamental question in contemporary astrophysics is the origin of the elements. Cosmochemistry seeks to answer when, how and where the chemical elements arose. Quantitative answers to these fundamental questions require a multi-disciplinary approach involving stellar evolution, explosive nucleosynthesis and nuclear reactions in different astrophysical environments. There remain, however, many outstanding problems and cosmochemistry remains a fertile area of research. This book is among the first in recent times to put together the essentials of cosmochemistry, combining contributions from leading astrophysicists in the field. The chapters have been organized to provide a clear description of the fundamentals, an introduction to modern techniques such as computational modelling, and glimpses of outstanding issues.

  13. Zrozeni z hvězd

    Czech Academy of Sciences Publication Activity Database

    Borovička, Jan

    2014-01-01

    Roč. 27, [2.8.2014] (2014), s. 21-21 ISSN 0862-5921 Institutional support: RVO:67985831 Keywords : chemistry * geochemistry * cosmochemistry * chemical elements * Sun * universe * Earth Subject RIV: DD - Geochemistry

  14. Discussion meeting on nuclear-, radio- and radiation chemistry - basics and applications

    International Nuclear Information System (INIS)

    1982-01-01

    The following fields have been represented at this meeting: 1. nuclear reactions and properties of the formed products; 2. geo- and cosmochemistry; 3. chemistry of actinides and other radioisotopes; 4. radioanalysis; 5. isotope applications; 6. nuclear fuel cycle. Single papers are listed under appropriate categories. (RB)

  15. Organic chemistry in space

    Science.gov (United States)

    Johnson, R. D.

    1977-01-01

    Organic cosmochemistry, organic materials in space exploration, and biochemistry of man in space are briefly surveyed. A model of Jupiter's atmosphere is considered, and the search for organic molecules in the solar system and in interstellar space is discussed. Materials and analytical techniques relevant to space exploration are indicated, and the blood and urine analyses performed on Skylab are described.

  16. Nuclear chemistry and geochemistry research. Carnegie Institute of Technology and Carnegie--Mellon University. Summary report

    International Nuclear Information System (INIS)

    Kohman, T.P.

    1976-01-01

    A summary is presented of the activities and results of research in nuclear chemistry, nuclear geochemistry, nuclear cosmochemistry, and other minor areas from 1950 to 1976. A complete listing is given of publications, doctoral dissertations, and reports resulting from the research. A chronological list provides an overview of the activities at any particular time

  17. V Congress of Spanish Geochemistry

    International Nuclear Information System (INIS)

    1993-01-01

    This proceedings book present the lectures of V Spanish geochemistry Congress. The sessions were: 1.- Materials geochemistry and geologic process. 2.- Geochemistry prospection 3.- Environmental geochemistry 4.- Isotopic geochemistry 5.- Organic geochemistry 6.- Natural materials geochemistry for industry 7.- Hydrogeochemistry 8.- Mathematical models in geochemistry 9.- Analysis methods in geochemistry 10.-Training of geochemistry 11.-Cosmochemistry

  18. Nuclear chemistry and geochemistry research. Carnegie Institute of Technology and Carnegie--Mellon University. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    Kohman, T.P.

    1976-05-28

    A summary is presented of the activities and results of research in nuclear chemistry, nuclear geochemistry, nuclear cosmochemistry, and other minor areas from 1950 to 1976. A complete listing is given of publications, doctoral dissertations, and reports resulting from the research. A chronological list provides an overview of the activities at any particular time. (JSR)

  19. Advances in geochemistry during the last four decades: A personal perspective

    International Nuclear Information System (INIS)

    Galimov, Eric M.

    2009-01-01

    This is the author's speech at the meeting in Cologne (2007) to celebrate the 40th anniversary of the International Association of Geochemistry and Cosmochemistry, which the author served as the President in 2000 to 2004. The paper narrates the author's personal involvement in important scientific programs during the last 4 decades, including implementation of isotope techniques, oil-and-gas research, diamond research, deep-sea drilling, space research, molecular biology and the origin of life.

  20. Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

    International Nuclear Information System (INIS)

    Ryan, R.R.

    1981-05-01

    This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research

  1. Experimental and Analytical Studies of Solar System Chemistry

    Science.gov (United States)

    Burnett, Donald S.

    2003-01-01

    The cosmochemistry research funded by this grant resulted in the publications given in the attached Publication List. The research focused in three areas: (1) Experimental studies of trace element partitioning. (2) Studies of the minor element chemistry and O isotopic compositions of MgAlO4 spinels from Ca-Al-Rich Inclusions in carbonaceous chondrite meteorites, and (3) The abundances and chemical fractionations of Th and U in chondritic meteorites.

  2. Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, R.R. (comp.)

    1981-05-01

    This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  3. Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

    International Nuclear Information System (INIS)

    Ryan, R.R.

    1982-05-01

    This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research

  4. Annual report 1980

    International Nuclear Information System (INIS)

    1981-01-01

    This annual report contains extended abstracts about the research done at the named institute. These abstracts concern the development of accelerators and ion sources, the construction of the magnetic spectrograph and radiation detectors, the investigation of solids and microstructures by nuclear methods, the development of electronic circuits, the advances in data processing, the study of heavy ion reactions, nuclear structure, and reaction mechanisms, the research on atomic physics and the interaction of charged particles with matter, the studies in medium and high energy physics, the theoretical studies of nuclear structure, and the research in cosmochemistry. Furthermore a list of publications is added. (orig./HSI) [de

  5. Modern Meteor Science An Interdisciplinary View

    CERN Document Server

    Hawkes, Robert; Brown, Peter

    2005-01-01

    This volume represents a blend of leading edge research and authoritative reviews in meteor science. It provides a comprehensive view of meteoroid research including the dynamics, sources and distribution of these bodies, and their chemistry and physical processes in the interplanetary medium and the Earth’s atmosphere. Techniques for investigation of meteor phenomena in the book include conventional and large aperture radar systems, spacecraft detection, optical systems, spectral measurements, and laboratory based interplanetary dust particle studies. The book will be of interest to researchers and students in astronomy, astrophysics, cosmochemistry, space engineering and space science. Cover photograph was taken by Masayuki Toda.

  6. The 13 000 000 000 year bang

    International Nuclear Information System (INIS)

    Rees, M.

    1976-01-01

    The new observational techniques which have revealed, in the past 20 years, a great range and richness of cosmic phenomena are reviewed. Especial reference is made to cosmological observations that have helped to firmly establish the Big Bang theory including; radio astronomy, discovery of the 2.7 K microwave background radiation, cosmochemistry, the discovery of quasars, and the evolution of galaxies. Accepting that the Universe exploded from an initial big bang the question whether expansion will continue for ever is discussed. (U.K.)

  7. Annual report 1979

    International Nuclear Information System (INIS)

    1980-01-01

    This annual report contains extended abstracts about the research done at the named institute. These abstracts concern the development of accelerators and ion sources, the construction of the magnetic spectrograph and radiation detectors, the investigation of solids and microstructures by nuclear methods, the development of electronic circuits, the advances in data processing, the study of heavy ion reactions, nuclear structure, and reaction mechanisms, the research on atomic physics and the interaction of charged particles with matter, the studies in medium and high energy physics, the theoretical studies of nuclear structure, and the research in cosmochemistry. Furthermore a list of publications is added. (orig./HSI) [de

  8. Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, R.R. (comp.)

    1982-05-01

    This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research.

  9. Planetary Science Research Discoveries (PSRD) www.psrd.hawaii.edu

    Science.gov (United States)

    Martel, L.; Taylor, J.

    2010-12-01

    NASA's Year of the Solar System is celebrating not only Solar System mission milestones but also the collective data reduction and analysis that happens here on Earth. The Cosmochemistry Program of NASA's Science Mission Directorate takes a direct approach to enhance student learning and engage the public in the latest research on meteorites, asteroids, planets, moons, and other materials in our Solar System with the website known as PSRD. The Planetary Science Research Discoveries (PSRD) website at www.psrd.hawaii.edu explores the science questions that researchers are actively pursuing about our Solar System and explains how the answers are discovered and what they mean. The site helps to convey the scientific basis for sample study to the broader scientific community and the excitement of new results in cosmochemistry to the general public. We share with our broad audience the fascinating discoveries made by cosmochemists, increasing public awareness of the value of sample-focused research in particular and of fundamental scientific research and space exploration in general. The scope of the website covers the full range of cosmochemical research and highlights the investigations of extraterrestrial materials that are used to better understand the origin of the Solar System and the processes by which planets, moons, and small bodies evolve. We relate the research to broader planetary science themes and mission results. Articles are categorized into: asteroids, comets, Earth, instruments of cosmochemistry, Jupiter system, Mars, Mars life issues, Mercury, meteorites, Moon, origins, and space weathering. PSRD articles are based on peer-reviewed, journal publications. Some PSRD articles are based on more than one published paper in order to present multiple views and outcomes of research on a topic of interest. To date, 150 PSRD articles have been based on 184 journal articles (and counting) written by some of the most active cosmochemists and planetary scientists

  10. Annual report 1975

    International Nuclear Information System (INIS)

    Harney, H.L.; Laemmerzahl, P.

    1975-01-01

    The nuclear physics investigations - mainly nuclear reaction studies - aim for a better understanding of atomic nuclei. The MPI has two Tandem-van-de-Graaff accelerators (type EN and MP) with 6 and 13 MV maximum voltage. Heavy ion physics has been a main field of research for many years. A post accelerator at the MP-tandem is to extend the available heavy ion beams towards higher energies and heavier masses. Research in the area of cosmochemistry is based on mass spectrometric, chemical, mineralogical and petrological studies which are carried out on lunar and meteoritic material in the hope of obtaining information about the origin and development of solid bodies in the solar system. A list instiute members and of publications in 1975 is included at the end of this report. (orig./BJ) [de

  11. Where is the future of nuclear chemistry

    International Nuclear Information System (INIS)

    1980-01-01

    The future potentials of nuclear chemistry as a natural science with a strong orientation towards practical applications has been discussed at this meeting of 45 experts coming from research institutes and laboratories working in the fields of radiochemistry, nuclear chemistry, inorganic and applied chemistry, hot-atom chemistry, radiobiology, and nuclear biology, and from the two nuclear research centres at Juelich and Karlsruhe. The discussion centred around the four main aspects of future work, namely 1. basic research leading to an extension of the periodic table, nuclear reactions, the chemistry of superheavy elements, cosmochemistry; 2. radionuclide technology and activation analysis; 3. nuclear fuel cycle and reprocessing processes together with ultimate disposal methods; 4. radiochemistry in the life sciences, including nuclear chemistry and applications. (HK) [de

  12. Assay of /sup 32/Si by liquid scintillation counting

    Energy Technology Data Exchange (ETDEWEB)

    Cumming, J B [Brookhaven National Lab., Upton, NY (USA)

    1983-10-03

    Application of the radioactivity of /sup 32/Si to problems of interest in geo- and cosmo-chemistry has been hampered by uncertainties in the half-life of this nuclide. A procedure for the stimulation assay of /sup 32/Si and its /sup 32/P daughter utilizing a liquid scintillation detector in association with a pulse height analyzer is described. The results indicate that /sup 32/Si can be assayed to an accuracy of a few percent by liquid scintillation counting techniques which do not require the preparation of an organic Si derivative. Combination of the mean specific activity with the /sup 32/Si abundance determined by accelerator-based mass spectrometry gave the reported 101+-18 year half-life.

  13. Topics in nuclear and radiochemistry for college curricula and high school science programs

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The concern with the current status and trends of nuclear chemistry and radiochemistry education in academic institutions was addressed in a recent workshop. The 1988 workshop considered the important contributions that scientist with nuclear and radiochemistry backgrounds have made and are continuing to make to other sciences and to various applied fields. Among the areas discussed were environmental studies, life sciences, materials science, separation technology, hot atom chemistry, cosmochemistry, and the rapidly growing field of nuclear medicine. It is intent of the organizer and participants of this symposium entitled Topics in Nuclear and Radiochemistry for College Curricula and High School Science Program'' to provide lecture material on topics related to nuclear and radiochemistry to educators. It is our hope that teachers, who may or may not be familiar with the field, will find this collections of articles useful and incorporate some of them into their lectures.

  14. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  15. Investigation of Isotope Anomalies in Meteorites and their Components

    DEFF Research Database (Denmark)

    Holst, Jesper Christian

    Cosmochemistry aims to clarify the origin of our solar system and the preconditions for life as we know it. Through the study of meteorites, it is possible to constrain our Sun’s birth environment, the formation and the evolution of the protoplanetary disk of dust and gas that evolved...... then terminated their evolution either on the asymptotic giant branch (AGB) or in supernova explosions at the time when low mass stars like our Sun were forming. In this way, matter incorporated into the nascent solar system must have had diverse origins, some being old inherited presolar grains, others being...... the bulk solar system. Therefore, in order to establish a detailed history of the early solar system and processing of the protoplanetary disk, it is critical to ascertain the isotope variability of a large range of elements of different nucleosynthetic origin. In this thesis, we establish methods...

  16. Irradiation history of meteoritic inclusions

    DEFF Research Database (Denmark)

    Wielandt, Daniel Kim Peel

    Understanding the formation and earliest evolution of our solar system is a longstanding goal shared by cosmochemistry, astronomy and astrophysics. Meteorites play a key role in this pursuit, providing a ground truth against which all theories must be weighed. Chondritic meteorites are in essence...... extraterrestrial sediments that contain Calcium-Aluminium-rich Inclusions (CAIs) and chondrules that formed as individual objects during the earliest stages of solar system evolution. They later accreted together to form large bodies, after spending up to several million years in individual orbit around the proto...... of presolar and protosolar materials, as well as evidence for the former presence of over 10 extinct shortlived radionuclei of varying stability and provenance that play a key role in deciphering early solar system evolution. Some shortlived radionuclei, such as 60Fe (T½ 2.5 Myr), must have formed...

  17. Three Proposed Compendia for Genesis Solar Wind Samples: Science Results, Collector Materials Characterization and Cleaning Techniques

    Science.gov (United States)

    Allton, J. H.; Calaway, M. J.; Nyquist, L. E.; Jurewicz, A. J. G.; Burnett, D. S.

    2018-01-01

    Final Paper and not the abstract is attached. Introduction: Planetary material and cosmochemistry research using Genesis solar wind samples (including the development and implementation of cleaning and analytical techniques) has matured sufficiently that compilations on several topics, if made publically accessible, would be beneficial for researchers and reviewers. We propose here three compendia based on content, organization and source of documents (e.g. published peer-reviewed, published, internal memos, archives). For planning purposes, suggestions are solicited from potential users of Genesis solar wind samples for the type of science content and/or organizational style that would be most useful to them. These compendia are proposed as living documents, periodically updated. Similar to the existing compendia described below, the curation compendia are like library or archival finding aids, they are guides to published or archival documents and should not be cited as primary sources.

  18. Calcium stable isotope geochemistry

    International Nuclear Information System (INIS)

    Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

    2016-01-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  19. Experiments in atomic and applied physics using synchrotron radiation

    International Nuclear Information System (INIS)

    Jones, K.W.

    1987-01-01

    A diverse program in atomic and applied physics using x rays produced at the X-26 beam line at the Brookhaven National Synchrotron Light Source is in progress. The atomic physics program studies the properties of multiply-ionized atoms using the x rays for photo-excitation and ionization of neutral atoms and ion beams. The applied physics program builds on the techniques and results of the atomic physics work to develop new analytical techniques for elemental and chemical characterization of materials. The results are then used for a general experimental program in biomedical sciences, geo- and cosmochemistry, and materials sciences. The present status of the program is illustrated by describing selected experiments. Prospects for development of new experimental capabilities are discussed in terms of a heavy ion storage ring for atomic physics experiments and the feasibility of photoelectron microscopy for high spatial resolution analytical work. 21 refs., 11 figs., 2 tabs

  20. Topics in nuclear and radiochemistry for college curricula and high school science programs

    International Nuclear Information System (INIS)

    1990-01-01

    The concern with the current status and trends of nuclear chemistry and radiochemistry education in academic institutions was addressed in a recent workshop. The 1988 workshop considered the important contributions that scientist with nuclear and radiochemistry backgrounds have made and are continuing to make to other sciences and to various applied fields. Among the areas discussed were environmental studies, life sciences, materials science, separation technology, hot atom chemistry, cosmochemistry, and the rapidly growing field of nuclear medicine. It is intent of the organizer and participants of this symposium entitled ''Topics in Nuclear and Radiochemistry for College Curricula and High School Science Program'' to provide lecture material on topics related to nuclear and radiochemistry to educators. It is our hope that teachers, who may or may not be familiar with the field, will find this collections of articles useful and incorporate some of them into their lectures

  1. Isotopic homogeneity of iron in the early solar nebula.

    Science.gov (United States)

    Zhu, X K; Guo, Y; O'Nions, R K; Young, E D; Ash, R D

    2001-07-19

    The chemical and isotopic homogeneity of the early solar nebula, and the processes producing fractionation during its evolution, are central issues of cosmochemistry. Studies of the relative abundance variations of three or more isotopes of an element can in principle determine if the initial reservoir of material was a homogeneous mixture or if it contained several distinct sources of precursor material. For example, widespread anomalies observed in the oxygen isotopes of meteorites have been interpreted as resulting from the mixing of a solid phase that was enriched in 16O with a gas phase in which 16O was depleted, or as an isotopic 'memory' of Galactic evolution. In either case, these anomalies are regarded as strong evidence that the early solar nebula was not initially homogeneous. Here we present measurements of the relative abundances of three iron isotopes in meteoritic and terrestrial samples. We show that significant variations of iron isotopes exist in both terrestrial and extraterrestrial materials. But when plotted in a three-isotope diagram, all of the data for these Solar System materials fall on a single mass-fractionation line, showing that homogenization of iron isotopes occurred in the solar nebula before both planetesimal accretion and chondrule formation.

  2. Present and future prospects of accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kutschera, W

    1988-05-20

    Accelerator mass spectrometry (AMS) has become a powerful technique for measuring extremely low abundances (10/sup -10/ to 10/sup -15/ relative to stable isotopes) of long-lived radioisotopes with half-lives in the range from 10/sup 2/ to 10/sup 8/ years. With a few exceptions, tandem accelerators turned out to be the most useful instruments for AMS measurements. Both natural (mostly cosmogenic) and manmade (anthropogenic) radioisotopes are studied with this technique. In some cases very low concentrations of stable isotopes are also measured. Applications of AMS cover a large variety of fields including anthropology, archaeology, oceanography, hydrology, climatology, volcanology, mineral exploration, cosmochemistry, meteoritics, glaciology, sedimentary processes, geochronology, environmental physics, astrophysics, nuclear and particle physics. Present and future prospects of AMS will be discussed as an interplay between the continuous development of new techniques and the investigation of problems in the above mentioned field. Depending on the specific problem to be investigated, different aspects of an AMS system are of importance. Typical factors to be considered are energy range and type of accelerator, and the possibilities of dedicated versus partial use of new or existing accelerators.

  3. 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.

  4. Accelerator mass spectrometry for measurement of long-lived radioisotopes.

    Science.gov (United States)

    Elmore, D; Phillips, F M

    1987-05-01

    Particle accelerators, such as those built for research in nuclear physics, can also be used together with magnetic and electrostatic mass analyzers to measure rare isotopes at very low abundance ratios. All molecular ions can be eliminated when accelerated to energies of millions of electron volts. Some atomic isobars can be eliminated with the use of negative ions; others can be separated at high energies by measuring their rate of energy loss in a detector. The long-lived radioisotopes (10)Be, (14)C,(26)A1, 36Cl, and (129)1 can now be measured in small natural samples having isotopic abundances in the range 10(-12) to 10(- 5) and as few as 10(5) atoms. In the past few years, research applications of accelerator mass spectrometry have been concentrated in the earth sciences (climatology, cosmochemistry, environmental chemistry, geochronology, glaciology, hydrology, igneous petrogenesis, minerals exploration, sedimentology, and volcanology), in anthropology and archeology (radiocarbon dating), and in physics (searches for exotic particles and measurement of halflives). In addition, accelerator mass spectrometry may become an important tool for the materials and biological sciences.

  5. Astrophysical implications of extraterrestrial materials: A special issue for Ernst K. Zinner

    Science.gov (United States)

    Nittler, Larry R.

    2018-01-01

    This special issue is dedicated to the memory of Dr. Ernst K. Zinner (Fig. 1). Dr. Zinner (1937-2015) was a pioneer in the use of Secondary Ion Mass Spectrometry (SIMS) in geo- and cosmochemistry. His contributions to science were vast, but in addition to his foundational SIMS development work, he is best known for the discovery and detailed characterization of presolar stardust grains in meteorites. This discovery opened up important new connections between astrophysics and meteoritical research and this is the overarching theme of this issue. Throughout his career, Ernst was a teacher, mentor, friend, and generous collaborator to legions of scientists. This issue presents research by many who were taught by, inspired by, and/or collaborated with this innovative cosmochemist and astrophysicist. In addition to the author, Ernst's former students and collaborators Drs. Christine Floss (Washington University) Peter Hoppe (MPI for chemistry, Mainz, Germany), and Kevin McKeegan (University of California, Los Angeles) served as Guest Editors for this issue.

  6. On the Detection and Characterization of Polluted White Dwarfs

    Science.gov (United States)

    Steele, Amy; Debes, John H.; Deming, Drake

    2017-06-01

    There is evidence of circumstellar material around main sequence, giant, and white dwarf stars. What happens to this material after the main sequence? With this work, we focus on the characterization of the material around WD 1145+017. The goals are to monitor the white dwarf—which has a transiting, disintegrating planetesimal and determine the composition of the evaporated material for that same white dwarf by looking at high-resolution spectra. We also present preliminary results of follow-up photometric observations of known polluted WDs. If rocky bodies survive red giant branch evolution, then the material raining down on a WD atmosphere is a direct probe of main sequence cosmochemistry. If rocky bodies do not survive the evolution, then this informs the degree of post-main-sequence processing. These case studies will provide the community with further insight about debris disk modeling, the degree of post-main-sequence processing of circumstellar material, and the composition of a disintegrating planetesimal.

  7. Measurements of iridium and the meteoric impact hypothesis at cretaceous end

    International Nuclear Information System (INIS)

    Sircilli Neto, F.

    1986-12-01

    Both instrumental and radiochemical neutron activation analysis methods were developed for trace-element determination, such as iridium and gold, for application in cosmochemistry. The magnitude of the determined concentrations is in the range of parts per billion. In the instrumental method 1.5 grams of sample were submitted to irradiation by 10 13 thermal neutrons.cm -2 .s -1 during 32 hours. The gamma spectrometry is carried out with 10 to 12 hours counting time after 40 days of decay. In the radiochemical analysis a method of radiochemical separation of noble metals based on tellurium coprecipitation is implanted for iridium and gold determinations. As an application of the instrumental neutron activation analysis, preliminary iridium concentrations are measured for the first time in sedimentary rocks collected in the Brazilian territory. These techniques for determinations of iridium will be useful to check the asteroid impact hypothesis, which is supposed to be the cause of the great Cretaceous/Tertiary mass extinction, using samples collected in the South Hemisphere. (Author) [pt

  8. Report on the Sixth International Symposium on Isotopomers

    Energy Technology Data Exchange (ETDEWEB)

    Bao, H. [Louisiana State Univ., Baton Rouge, LA (United States); Farquhar, J. [Univ. of Maryland, College Park, MD (United States); Rumble, D. [Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab.

    2016-05-11

    The ISI 2012 met in Washington, DC, 18-22 June 2012, bringing together researchers and their students spanning an unusually wide range of disciplines including quantum and physical chemistry, cosmochemistry, atmospheric chemistry, chemical oceanography, biogeochemistry, organic and inorganic geochemistry. The diversity of subject matter was matched geographically with 92 attendees hailing from Canada, China, Finland, France, Germany, India, Israel, Japan, the Netherlands, Russia, Switzerland, Taiwan, the United Kingdom, and the USA. Although diverse, the group was united in its commitment to use the light stable isotopes of H, C, N, O, and S, with their equilibrium, kinetic, and intramolecular fractionations, to understand the material cycles and their dynamics between atmosphere, biosphere, hydrosphere, and lithosphere that make life possible on Earth. A distinct benefit of a small meeting like ISI 2012 is the opportunity for everyone to talk to each other. The historic rooms of the Carnegie Institution of Washington offered a cozy and warm atmosphere for participants in ISI 2012 to talk science and life in a casual, relaxed, and in-depth fashion. Graduate students and postdoctoral researchers were particularly appreciative of being able to spend five days together with old and new colleagues in comfortable quarters. Many commented that they had gained a lot more in building their life-long working relationships with colleagues at this meeting than at larger meetings.

  9. A web-based course in nuclear and radiochemistry

    International Nuclear Information System (INIS)

    Landsberger, S.; Plionis, A.

    2009-01-01

    Over the last six years through a Department of Energy Radiochemistry Education Award Program (REAP) we have developed a completely webbased course in nuclear and radiochemistry given at the University of Texas at Austin. This course has had nuclear and radiation engineering and chemistry graduate students. While the course also has an extensive laboratory component only the lectures are web based. The lectures begin with a historical introduction of radiochemistry followed by two movies on Madame Curie. This is followed by the usual lectures on radioactivity, fundamental properties, radioactive decay, decay modes, and nuclear reactions. As section on radioactive waste management and nuclear fuel cycle is also presented. Lectures in neutron activation analysis, geo- and cosmochemistry, and plutonium chemistry have also been developed. All lectures are in power point with many animations and a significant number of solved problems. All students are required to make a short oral presentation on some aspect of nuclear and radiochemistry in their research or a chosen topic. (author)

  10. Physical and Chemical Study of Minerals and Rocks Containing Low-Z Compounds of Interest to Astrobiology and Origin of Life

    Science.gov (United States)

    1999-01-01

    Understanding the origins of Life requires a good understanding of the physics and chemistry of biogenic low-z elements H, C, N, O, P, S in terrestrial environments, on Mars, on extraterrestrial bodies such as meteorite parent bodies and comets, and in interstellar space. In this Proposal five Tasks form a coherent program aimed at elucidating various aspects of low-z element geo- and cosmochemistry with special reference to the origin of Life on Earth and to the search for life on Mars, extant or extinct. (i) Formation of organic molecules, in particular oxygenated H-C-0 molecules or precursors thereof of the composition H(x)C(y)O(z)(n-), inside the hard matrix of structurally dense magmatic minerals; (ii) Formation of organic molecules inside the soft matrix of amorphous and crystalline water ice; (iii) Preservation of organic molecules in cherts and other siliceous rocks formed in hot spring or submarine hydrothermal vent environments; (iv) The nature of the elusive Martian soil oxidant; and (v) Prototype development of an XRD instrument, using a new patented XRD camera concept that utilizes a Charge Coupled Device (CCD) as a camera and as a energy-dispersive analyzer.

  11. Physics in a mad world

    CERN Document Server

    2016-01-01

    This book tells captivating stories of misadventures of two renowned theoretical physicists in the Soviet Union. The first part is devoted to Friedrich (Fritz) Houtermans, an outstanding Dutch–Austrian–German physicist who was the first to suggest that the source of stars' energy is thermonuclear fusion, and also made a number of other important contributions to cosmochemistry and geochemistry. In 1935, Houtermans, a German communist, in an attempt to save his life from Hilter's Gestapo, fled to the Soviet Union. He took up an appointment at the Kharkov Physico-Technical Institute, working there for two years with the Russian physicist Valentin P Fomin. In the Great Purge of 1937, Houtermans was arrested in December by the NKVD (Soviet Secret Police, KGB's predecessor). He was tortured, and confessed to being a Trotskyist plotter and German spy, out of fear of threats against his wife Charlotte. However, Charlotte had already escaped from the Soviet Union to Denmark, after which she went to England and fi...

  12. Present and future prospects of accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Kutschera, W.

    1987-04-01

    Accelerator Mass Spectrometry (AMS) has become a powerful technique for measuring extremely low abundances (10 -10 to 10 -15 relative to stable isotopes) of long-lived radioisotopes with half-lives in the range from 10 2 to 10 8 years. With a few exceptions, tandem accelerators turned out to be the most useful instruments for AMS measurements. Both natural (mostly cosmogenic) and man-made (anthropogenic) radioisotopes are studied with this technique. In some cases very low concentrations of stable isotope are also measured. Applications of AMS cover a large variety of fields including anthropology, archaeology, oceanography, hydrology, climatology, volcanology, minerals exploration, cosmochemistry, meteoritics, glaciology, sedimentary processes, geochronology, environmental physics, astrophysics, nuclear and particle physics. Present and future prospects of AMS are discussed as an interplay between the continuous development of new techniques and the investigation of problems in the above mentioned fields. Typical factors to be considered are energy range and type of accelerator, and the possibilities of dedicated versus partial use of new or existing accelerators

  13. Noble Gases

    Science.gov (United States)

    Podosek, F. A.

    2003-12-01

    The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the

  14. Laboratory Studies of the Formation of Carbonaceous Cosmic Dust from PAH Precursors

    Science.gov (United States)

    Salama, Farid; Contreras, C. S.

    2012-05-01

    supported by the NASA SMD Cosmochemistry and APRA programs. C.S.C. acknowledges the support of the NASA Postdoctoral Program.

  15. DUSTER: collection of meteoric CaO and carbon smoke particles in the upper stratosphere .

    Science.gov (United States)

    Della Corte, V.; Rietmeijer, F. J. M.; Rotundi, A.; Ferrari, M.; Palumbo, P.

    Nanometer- to micrometer-size particles present in the upper stratosphere are a mixture of terrestrial and extra-terrestrial origins. They can be extraterrestrial particles condensed after meteor ablation. Meteoric dust in bolides is occasionally deposited into the lower stratosphere around 20 km altitude. Nanometer CaO and pure carbon smoke particles were collected at 38 km altitude in the upper stratosphere in the Arctic during June 2008 using DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval), a balloon-borne instrument for the non-destructive collection of solid particles between 200 nm to 40 microns. We report the collection of micron sized CaCO_3 (calcite) grains. Their morphologies show evidence of melting and condensation after vaporization suggest at temperatures of approximately 3500 K. The formation environment of the collected grains was probably a dense dust cloud formed by the disintegration of a carbonaceous meteoroid during deceleration in the Earth� atmosphere. For the first time, DUSTER collected meteor ablation products that were presumably associated with the disintegration of a bolide crossing the Earth's atmosphere. The collected mostly CaO and pure carbon nanoparticles from the debris cloud of a fireball, included: 1) intact fragments; 2) quenched melted grains; and 3) vapor phase condensation products. The DUSTER project was funded by the Italian Space Agency (ASI), PRIN2008/MIUR (Ministero dell'Istruzione dell'Universitá e della Ricerca), PNRA 2013(Piano Nazionale Ricerca Antartide). CNES graciously provided this flight opportunity. We thank E. Zona and S. Inarta at the Laboratorio di Fisica Cosmica INAF, Osservatorio Astronomico di Capodimonte-Universitá di Napoli Parthenope. F.J.M.R. was supported by grant NNX07AI39G from the NASA Cosmochemistry Program. We thank three anonymous reviewers who assisted us in introducing our new instrument.

  16. Fe isotope composition of bulk chondrules from Murchison (CM2): Constraints for parent body alteration, nebula processes and chondrule-matrix complementarity

    Science.gov (United States)

    Hezel, Dominik C.; Wilden, Johanna S.; Becker, Daniel; Steinbach, Sonja; Wombacher, Frank; Harak, Markus

    2018-05-01

    Chondrules are a major constituent of primitive meteorites. The formation of chondrules is one of the most elusive problems in cosmochemistry. We use Fe isotope compositions of chondrules and bulk chondrites to constrain the conditions of chondrule formation. Iron isotope compositions of bulk chondrules are so far only known from few studies on CV and some ordinary chondrites. We studied 37 chondrules from the CM chondrite Murchison. This is particularly challenging, as CM chondrites contain the smallest chondrules of all chondrite groups, except for CH chondrites. Bulk chondrules have δ56Fe between -0.62 and +0.24‰ relative to the IRMM-014 standard. Bulk Murchison has as all chondrites a δ56Fe of 0.00‰ within error. The δ56Fe distribution of the Murchison chondrule population is continuous and close to normal. The width of the δ56Fe distribution is narrower than that of the Allende chondrule population. Opaque modal abundances in Murchison chondrules is in about 67% of the chondrules close to 0 vol.%, and in 33% typically up to 6.5 vol.%. Chondrule Al/Mg and Fe/Mg ratios are sub-chondritic, while bulk Murchison has chondritic ratios. We suggest that the variable bulk chondrule Fe isotope compositions were established during evaporation and recondensation prior to accretion in the Murchison parent body. This range in isotope composition was likely reduced during aqueous alteration on the parent body. Murchison has a chondritic Fe isotope composition and a number of chondritic element ratios. Chondrules, however, have variable Fe isotope compositions and chondrules and matrix have complementary Al/Mg and Fe/Mg ratios. In combination, this supports the idea that chondrules and matrix formed from a single reservoir and were then accreted in the parent body. The formation in a single region also explains the compositional distribution of the chondrule population in Murchison.

  17. The CN/C15N isotopic ratio towards dark clouds

    Science.gov (United States)

    Hily-Blant, P.; Pineau des Forêts, G.; Faure, A.; Le Gal, R.; Padovani, M.

    2013-09-01

    Understanding the origin of the composition of solar system cosmomaterials is a central question, not only in the cosmochemistry and astrochemistry fields, and requires various approaches to be combined. Measurements of isotopic ratios in cometary materials provide strong constraints on the content of the protosolar nebula. Their relation with the composition of the parental dark clouds is, however, still very elusive. In this paper, we bring new constraints based on the isotopic composition of nitrogen in dark clouds, with the aim of understanding the chemical processes that are responsible for the observed isotopic ratios. We have observed and detected the fundamental rotational transition of C15N towards two starless dark clouds, L1544 and L1498. We were able to derive the column density ratio of C15N over 13CN towards the same clouds and obtain the CN/C15N isotopic ratios, which were found to be 500 ± 75 for both L1544 and L1498. These values are therefore marginally consistent with the protosolar value of 441. Moreover, this ratio is larger than the isotopic ratio of nitrogen measured in HCN. In addition, we present model calculations of the chemical fractionation of nitrogen in dark clouds, which make it possible to understand how CN can be deprived of 15N and HCN can simultaneously be enriched in heavy nitrogen. The non-fractionation of N2H+, however, remains an open issue, and we propose some chemical way of alleviating the discrepancy between model predictions and the observed ratios. Appendices are available in electronic form at http://www.aanda.orgThe reduced spectra (in FITS format) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A65

  18. The distribution of uranium over Europe: Geological and environmental significance

    Science.gov (United States)

    Plant, J.A.; Reeder, S.; Salminen, R.; Smith, D.B.; Tarvainen, T.; de Vivo, B.; Petterson, M.G.

    2003-01-01

    The variation of baseline levels of uranium in soil and stream sediments over Europe is described, based on new data prepared by the Forum of European Geological Surveys (FOREGS). The samples have been collected and analysed according to the protocols established for the International Union of Geological Sciences/International Association of Geochemistry and Cosmochemistry (IUGS/IAGC) Working Group on Global Geochemical Baselines. The baseline levels of U vary between 0??21 to 53 mg kg-1 in topsoils, 0??19 to 30 mg kg-1 in subsoils and sample types, and the median concentration in all three media is approximately 2 mg kg-1. The most anomalous baseline levels occur over the Variscan orogen, especially areas into which late post-orogenic radiothermal high heat production (HHP) granites were emplaced. Spiderdiagrams based on trace element levels and rare earth element (REE) plots, confirm the association between the highest U anomalies and evolved radiothermal granites. High values are also associated with parts of the Alpine terrain especially in Slovenia, where there are historical U workings, and Southern Italy, where high values of U reflect contemporary volcanism. In contrast, much of the Caledonides of North West Europe and the Precambrian of the Baltic Shield and East European craton and its overlying sedimentary cover have very low values, generally radiation and radon potential associated with radiothermal granites. This is likely to be especially important where the granites are mineralised and have been worked historically, for example in the North West of the Iberian Peninsula where U and its decay products are likely to be more dispersed in the surface environment. The study also indicates the value of multi-element data in distinguishing between anthropogenic and naturally occurring anomalies.

  19. Modification of REE distribution of ordinary chondrites from Atacama (Chile) and Lut (Iran) hot deserts: Insights into the chemical weathering of meteorites

    Science.gov (United States)

    Pourkhorsandi, Hamed; D'Orazio, Massimo; Rochette, Pierre; Valenzuela, Millarca; Gattacceca, Jérôme; Mirnejad, Hassan; Sutter, Brad; Hutzler, Aurore; Aboulahris, Maria

    2017-09-01

    The behavior of rare earth elements (REEs) during hot desert weathering of meteorites is investigated. Ordinary chondrites (OCs) from Atacama (Chile) and Lut (Iran) deserts show different variations in REE composition during this process. Inductively coupled plasma-mass spectrometry (ICP-MS) data reveal that hot desert OCs tend to show elevated light REE concentrations, relative to OC falls. Chondrites from Atacama are by far the most enriched in REEs and this enrichment is not necessarily related to their degree of weathering. Positive Ce anomaly of fresh chondrites from Atacama and the successive formation of a negative Ce anomaly with the addition of trivalent REEs are similar to the process reported from Antarctic eucrites. In addition to REEs, Sr and Ba also show different concentrations when comparing OCs from different hot deserts. The stability of Atacama surfaces and the associated old terrestrial ages of meteorites from this region give the samples the necessary time to interact with the terrestrial environment and to be chemically modified. Higher REE contents and LREE-enriched composition are evidence of contamination by terrestrial soil. Despite their low degrees of weathering, special care must be taken into account while working on the REE composition of Atacama meteorites for cosmochemistry applications. In contrast, chondrites from the Lut desert show lower degrees of REE modification, despite significant weathering signed by Sr content. This is explained by the relatively rapid weathering rate of the meteorites occurring in the Lut desert, which hampers the penetration of terrestrial material by forming voluminous Fe oxide/oxyhydroxides shortly after the meteorite fall.

  20. Institute of Geophyics and Planetary Physics. Annual report for FY 1994

    Energy Technology Data Exchange (ETDEWEB)

    Ryerson, F.J. [ed.

    1995-09-29

    The Institute of Geophysics and Planetary Physics (IGPP) is a Multicampus Research Unit of the University of California (UC). IGPP was founded in 1946 at UC Los Angeles with a charter to further research in the earth and planetary sciences and in related fields. The Institute now has branches at UC campuses in Los Angeles, San Diego, Riverside, and Irvine and at Los Alamos and Lawrence Livermore national laboratories. The University-wide IGPP has played an important role in establishing interdisciplinary research in the earth and planetary sciences. For example, IGPP was instrumental in founding the fields of physical oceanography and space physics, which at the time fell between the cracks of established university departments. Because of its multicampus orientation, IGPP has sponsored important interinstitutional consortia in the earth and planetary sciences. Each of the six branches has a somewhat different intellectual emphasis as a result of the interplay between strengths of campus departments and Laboratory programs. The IGPP branch at Lawrence Livermore National Laboratory (LLNL) was approved by the Regents of the University of California in 1982. IGPP-LLNL emphasizes research in seismology, geochemistry, cosmochemistry, high-pressure sciences, and astrophysics. It provides a venue for studying the fundamental aspects of these fields, thereby complementing LLNL programs that pursue applications of these disciplines in national security and energy research. IGPP-LLNL is directed by Charles Alcock and is structured around three research centers. The Center for Geosciences, headed by George Zandt and Frederick Ryerson, focuses on research in geophysics and geochemistry. The Center for High-Pressure Sciences, headed by William Nellis, sponsors research on the properties of planetary materials and on the synthesis and preparation of new materials using high-pressure processing.

  1. EURO-CARES: European Roadmap for a Sample Return Curation Facility and Planetary Protection Implications.

    Science.gov (United States)

    Brucato, John Robert

    2016-07-01

    A mature European planetary exploration program and evolving sample return mission plans gathers the interest of a wider scientific community. The interest is generated from studying extraterrestrial samples in the laborato-ry providing new opportunities to address fundamental issues on the origin and evolution of the Solar System, on the primordial cosmochemistry, and on the nature of the building blocks of terrestrial planets and on the origin of life. Major space agencies are currently planning for missions that will collect samples from a variety of Solar Sys-tem environments, from primitive (carbonaceous) small bodies, from the Moon, Mars and its moons and, final-ly, from icy moons of the outer planets. A dedicated sample return curation facility is seen as an essential re-quirement for the receiving, assessment, characterization and secure preservation of the collected extraterrestrial samples and potentially their safe distribution to the scientific community. EURO-CARES is a European Commission study funded under the Horizon-2020 program. The strategic objec-tive of EURO-CARES is to create a roadmap for the implementation of a European Extraterrestrial Sample Cu-ration Facility. The facility has to provide safe storage and handling of extraterrestrial samples and has to enable the preliminary characterization in order to achieve the required effectiveness and collaborative outcomes for the whole international scientific community. For example, samples returned from Mars could pose a threat on the Earth's biosphere if any living extraterrestrial organism are present in the samples. Thus planetary protection is an essential aspect of all Mars sample return missions that will affect the retrival and transport from the point of return, sample handling, infrastructure methodology and management of a future curation facility. Analysis of the state of the art of Planetary Protection technology shows there are considerable possibilities to define and develop

  2. Fifty years of high energy chemistry. Current situation and perspectives of development in the Slovak Republic and the Czech Republic

    International Nuclear Information System (INIS)

    Kuruc, J.

    2017-01-01

    includes several chemical fields (including energy-generating carriers) such as radiation chemistry, photochemistry and laser chemistry, plasma chemistry, sonochemistry, photoelectrochemistry, cosmochemistry, hot atom chemistry, photoradiation chemistry, and chemical sciences caused by a group of low energy carriers: sonochemistry, mechanochemistry, shockwave, magnetochemistry and other chemical fields, e.g. luminescent phenomena. The individual problems of HECH, including the current state in the world and experimental equipment in the Slovak Republic and the Czech Republic, are discussed. (author)

  3. AMS-measurements of stable platinum isotopes in presolar nanodiamonds with the help of a negative-ion-injector for VERA

    International Nuclear Information System (INIS)

    Melber, K.

    2011-01-01

    The Vienna Environmental Research Accelerator (VERA) is a universal facility for Accelerator Mass Spectrometry (AMS). VERA is based on a 3-MV tandemaccelerator and enables one to investigate isotope ratios down to 10 -16 over the whole mass range of the elements. The main application is the measurement of long-lived radioisotopes of cosmogenic or anthropogenic origin (e.g. 10 Be, 14 C, 26 Al, 36 Cl, 41 Ca, 129 I, 236 U, 244 Pu). In principle it is also possible to detect stable isotopes of trace elements (Trace Element AMS: TEAMS). TEAMS is of particular interest with regard to so-called presolar grains in meteorites. Presolar grains contain trace elements whose isotope compositions differ substantially from those of our solar system. This points to a presolar origin of these grains. Among presolar grains, nanodiamonds are still poorly understood. They are composed of only a few thousand carbon atoms and contain platinum as one of the trace elements. There are still questions on their origin. E.g. were they 'doped' with the trace elements in the environment of a supernova? Which nucleosynthetic processes have taken place? Here the isotope signatures could deliver additional information. The aim of the present work was to establish conditions at VERA for the measurement of stable platinum isotopes in presolar nanodiamonds. The difficulty of such a measurement lies in the fact that trace analyses of stable Pt isotopes are only possible if the platinum background of the ion source is low. Hence, a new negative ion injector with a new sputtersource in which platinum was never used as a test material was build up at VERA. It was then possible to carry out Pt-isotope measurements in nanodiamonds for the first time. The sample material originates from the Allende-meteorite and was purified for nanodiamonds by the cosmochemistry group of the Max Planck Institute of Chemistry in Mainz. As a main result of the measurements it was possible to detect an access of the heaviest

  4. A new combined nanoSIMS and continuous-flow IRMS approach to measure hydrogen isotopes from water in hydrated rhyolitic glass

    Science.gov (United States)

    Gatti, E.; Kitchen, N.; Newman, S.; Guan, Y.; Westgate, J.; Pearce, N. J. G.; Nikolic, D.; Eiler, J. M.

    2016-12-01

    Geochemistry and Cosmochemistry at California Institute of Technology, in order to define the reliability of the bulk method and assess natural variability within and among grains.

  5. Radioactivation analysis

    International Nuclear Information System (INIS)

    1959-01-01

    Radioactivation analysis is the technique of radioactivation analysis of the constituents of a very small sample of matter by making the sample artificially radioactive. The first stage is to make the sample radioactive by artificial means, e.g. subject it to neutron bombardment. Once the sample has been activated, or made radioactive, the next task is to analyze the radiations given off by the sample. This analysis would indicate the nature and quantities of the various elements present in the sample. The reason is that the radiation from a particular radioisotope. In 1959 a symposium on 'Radioactivation Analysis' was organized in Vienna by the IAEA and the Joint Commission on Applied Radioactivity (ICSU). It was pointed out that there are certain factors creating uncertainties and elaborated how to overcome them. Attention was drawn to the fact that radioactivation analysis had proven a powerful tool tackling fundamental problems in geo- and cosmochemistry, and a review was given of the recent work in this field. Because of its extreme sensitivity radioactivation analysis had been principally employed for trace detection and its most extensive use has been in control of semiconductors and very pure metals. An account of the experience gained in the USA was given, where radioactivation analysis was being used by many investigators in various scientific fields as a practical and useful tool for elemental analyses. Much of this work had been concerned with determining sub microgramme and microgramme concentration of many different elements in samples of biological materials, drugs, fertilizers, fine chemicals, foods, fuels, glass, ceramic materials, metals, minerals, paints, petroleum products, resinous materials, soils, toxicants, water and other materials. In addition to these studies, radioactivation analysis had been used by other investigators to determine isotopic ratios of the stable isotopes of some of the elements. Another paper dealt with radioactivation

  6. Trace element analysis by EPMA in geosciences: detection limit, precision and accuracy

    Science.gov (United States)

    Batanova, V. G.; Sobolev, A. V.; Magnin, V.

    2018-01-01

    were found to be identical (within internal precision) to reference values, suggesting that achieved precision and accuracy are similar. The spatial resolution of EPMA in a silicate matrix, even at very extreme conditions (accelerating voltage 25 kV), does not exceed 7 - 8 μm and thus is still better than laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) or secondary ion mass spectrometry (SIMS) of similar precision. These make the electron microprobe an indispensable method with applications in experimental petrology, geochemistry and cosmochemistry.

  7. The 230Th correction is the 1st priority for accurate dates of young zircons: U/Th partitioning experiments and measurements

    Science.gov (United States)

    Krawczynski, M.; McLean, N.

    2017-12-01

    this study will reduce the largest source of uncertainty in dating young zircons and improve the accuracy of U-Pb dates, improving our ability to tell time during geologic processes. The attainment of more accurate timing of the geologic timescale is important to geologists of all disciplines, from paleontology to planetary cosmochemistry to geobiology.

  8. Mass-Dependent and -Independent Fractionation of Mercury Isotopes in Aquatic Systems

    Science.gov (United States)

    Bergquist, B. A.; Joel, B. D.; Jude, D. J.

    2008-12-01

    Mercury is a globally distributed and highly toxic pollutant. Although Hg is a proven health risk, much of the natural cycle of Hg is not well understood and new approaches are needed to track Hg and the chemical transformations it undergoes in the environment. Recently, we demonstrated that Hg isotopes exhibit two types of isotope fractionation: (1) mass dependent fractionation (MDF) and (2) mass independent fractionation (MIF) of only the odd isotopes (Bergquist and Blum, 2007). The observation of large MIF of Hg isotopes (up to 5 permil) is exciting because only a few other isotopic systems have been documented to display large MIF, the most notable of which are oxygen and sulfur. In both cases, the application of MIF has proven very useful in a variety of fields including cosmochemistry, paleoclimatology, physical chemistry, atmospheric chemistry, and biogeochemistry. Both MDF and MIF isotopic signatures are observed in natural samples, and together they open the door to a new method for tracing Hg pollution and for investigating Hg behavior in the environment. For example, fish record MDF that appears to be related to size and age. Additionally, fish display MIF signatures that are consistent with the photo-reduction of methylmercury (Bergquist and Blum, 2007). If the MDF and MIF in ecosystems can be understood, the signatures in fish could inform us about the sources and processes transforming Hg and why there are differences in the bioaccumulation of Hg in differing ecosystems and populations of fish. This requires sampling of a variety of ecosystems, the sampling of many components of the ecosystems, and the use of other tracers such as carbon and nitrogen isotopes. We have expanded our studies of aquatic ecosystems to include several lakes in North America. Similar to other isotopic systems used to study food web dynamics and structure (i.e., C and N), the MDF of Hg in fish appears to be related to size and age. The MDF recorded in fish likely reflects

  9. Radioactivation analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-07-15

    Radioactivation analysis is the technique of radioactivation analysis of the constituents of a very small sample of matter by making the sample artificially radioactive. The first stage is to make the sample radioactive by artificial means, e.g. subject it to neutron bombardment. Once the sample has been activated, or made radioactive, the next task is to analyze the radiations given off by the sample. This analysis would indicate the nature and quantities of the various elements present in the sample. The reason is that the radiation from a particular radioisotope. In 1959 a symposium on 'Radioactivation Analysis' was organized in Vienna by the IAEA and the Joint Commission on Applied Radioactivity (ICSU). It was pointed out that there are certain factors creating uncertainties and elaborated how to overcome them. Attention was drawn to the fact that radioactivation analysis had proven a powerful tool tackling fundamental problems in geo- and cosmochemistry, and a review was given of the recent work in this field. Because of its extreme sensitivity radioactivation analysis had been principally employed for trace detection and its most extensive use has been in control of semiconductors and very pure metals. An account of the experience gained in the USA was given, where radioactivation analysis was being used by many investigators in various scientific fields as a practical and useful tool for elemental analyses. Much of this work had been concerned with determining sub microgramme and microgramme concentration of many different elements in samples of biological materials, drugs, fertilizers, fine chemicals, foods, fuels, glass, ceramic materials, metals, minerals, paints, petroleum products, resinous materials, soils, toxicants, water and other materials. In addition to these studies, radioactivation analysis had been used by other investigators to determine isotopic ratios of the stable isotopes of some of the elements. Another paper dealt with radioactivation

  10. Fifty years of high energy chemistry. Current situation and perspectives of development in the Slovak Republic and the Czech Republic

    International Nuclear Information System (INIS)

    Kuruc, J.

    2017-01-01

    several chemical fields (including energy-generating carriers) such as radiation chemistry, photochemistry and laser chemistry, plasma chemistry, sonochemistry, photoelectrochemistry, cosmochemistry, hot atom chemistry, photoradiation chemistry, and chemical sciences caused by a group of low energy carriers: sonochemistry, mechanochemistry, shockwave, magnetochemistry and other chemical fields, e.g. luminescent phenomena. The individual problems of HECH, including the current state in the world and experimental equipment in the Slovak Republic and the Czech Republic, are discussed. (author)

  11. ARES Biennial Report 2012 Final

    Science.gov (United States)

    Stansbery, Eileen

    2014-01-01

    , which relies on access to the samples. The curation efforts are greatly enhanced by a strong group of planetary scientists who conduct peerreviewed astromaterials research. Astromaterials Research Office scientists conduct peer-reviewed research as Principal or Co-Investigators in planetary science (e. g., cosmochemistry, origins of solar systems, Mars fundamental research, planetary geology and geophysics) and participate as Co-Investigators or Participating Scientists in many of NASA's robotic planetary missions. Since the last report, ARES has achieved several noteworthy milestones, some of which are documented in detail in the sections that follow. Within the Human Exploration Science Office, ARES is a world leader in orbital debris research, modeling and monitoring the debris environment, designing debris shielding, and developing policy to control and mitigate the orbital debris population. ARES has aggressively pursued refinements in knowledge of the debris environment and the hazard it presents to spacecraft. Additionally, the ARES Image Science and Analysis Group has been recognized as world class as a result of the high quality of near-real-time analysis of ascent and on-orbit inspection imagery to identify debris shedding, anomalies, and associated potential damage during Space Shuttle missions. ARES Earth scientists manage and continuously update the database of astronaut photography that is predominantly from Shuttle and ISS missions, but also includes the results of 40 years of human spaceflight. The Crew Earth Observations Web site (http://eol.jsc.nasa.gov/Education/ESS/crew.htm) continues to receive several million hits per month. ARES scientists are also influencing decisions in the development of the next generation of human and robotic spacecraft and missions through laboratory tests on the optical qualities of materials for windows, micrometeoroid/orbital debris shielding technology, and analog activities to assess surface science operations. ARES

  12. Isotopic Investigations of Nebular and Parent Body Processes with a High Sensitivity Ion Microprobe

    Science.gov (United States)

    McKeegan, Kevin D.

    2005-01-01

    NASA supported the development of the CAMECA ims 1270 ion microprobe at UCLA for applications in cosmochemistry. The primary investigations centered on measuring the microscopic distributions of key isotopic abundances in primitive meteoritic materials as a means of constraining the nature of important thermal and chemical processes in the solar nebula and the timescales associated with those processes. Our prior work on oxygen isotope anomalies in a wide variety of meteoritic materials had led us to a view of a spatially heterogeneous nebula, and in particular, a restricted region for CAI formation that is characterized by O-16-rich gas. Because of its production of CAIs in the energetic local environment near the protosun, the existence of a natural transport mechanism via bipolar outflows, and a general astrophysical plausibility, we were attracted to the fluctuating X-wind model which had been put forward by Frank Shu, Typhoon Lee, and colleagues. With our collaborators, we undertook a series of investigations to test the viability of this hypothesis; this work led directly to the discovery of live Be in CAIs and a clear demonstration of the existence of 160-rich condensates, which necessarily implies an O-16-rich gaseous reservoir in the nebula. Both of these observations fit well within the context of X-wind type models, i.e. formation of CAIs (or condensation of their precursors) in the reconnection ring sunward of the inner edge of the accretion disk, however much work remains to be done to test whether the physical parameters of the model can quantitatively predict not only the thermal histories of CAIs but also their radioactivity. The issue of spatial heterogeneity in the nebula, central to the X-wind model, is also at the heart of any chronology based on short-lived radioisotopes. In this work, we followed up on strong hints for presence of exireme:j: (53 day) short-lived Be-7, and have prepared a manuscript (in revision). We also measured A1-Mg

  13. A miniaturized laser-ablation mass spectrometer for in-situ measurements of isotope composition on solar body surfaces

    Science.gov (United States)

    Riedo, A.; Meyer, S.; Tulej, M.; Neuland, M.; Bieler, A.; Iakovleva, M.; Wurz, P.

    2012-04-01

    The in-situ analysis of extraterrestrial material onboard planetary rovers and landers is of considerable interest for future planetary space missions. Due to the low detection sensitivity of spectroscopic instruments, e.g. α-particle X-ray, γ-ray or neutron spectrometers, it is frequently possible to measure only major/minor elements in extraterrestrial materials. Nevertheless, the knowledge of minor/trace elements is of considerable interest to cosmochemistry. Chemistry puts constraints on the origin of solar system and its evolution enabling also a deeper inside to planetary transformation processes (e.g. volcanic surface alteration, space weathering). The isotopes play special role in analysis of the origin and transformation of planetary matter. They are robust tracers of the early events because their abundances are less disturbed as the elemental once. Nevertheless, if the isotope abundance ratios are fractionated, the underlying chemical and physical processes can be then encoded from the variations of abundance ratios. A detailed analysis of isotopic patterns of radiogenic elements can allow age dating of minerals and temporal evolution of planetary matter. High accuracy and sensitive measurements of isotopic pattern of bio-relevant elements, i.e., sulfur, found on planetary surfaces can be helpful for the identification of possible past and present extraterrestrial life in terms of biomarker identification. Our group has designed a self-optimizing miniaturized laser ablation time-of-flight mass spectrometer (LMS) for in situ planetary measurements (Wurz et al., 2012; Rohner et al., 2003). Initial studies utilizing IR laser radiation for ablation, atomization and ionization of solid materials indicated a high instrumental performance in terms of sensitivity and mass resolution (Tulej et al., 2011). Current studies are conducted with a UV radiation and a high spatial resolution is achieved by focussing the laser beam to 20µm spots onto the sample. The

  14. HCN Polymers: Toward Structure Comprehension Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Bonnet, Jean-Yves; Thissen, Roland; Frisari, Ma; Vuitton, Veronique; Quirico, Eric; Le Roy, Léna; Fray, Nicolas; Cottin, Hervé; Horst, Sarah; Yelle, Roger

    derive quantitative and qualitative parameters, (H/C, N/C ratios for exemple). [1] D. P. Cruikshank, H. Imanaka, and C. M. Dalle Ore. Tholins as coloring agents on outer Solar System bodies. Advances in Space Research, 36:178-183, 2005. [2] H. Cottin and N. Fray. Distributed Sources in Comets. Space Science Reviews, 138:179-197, July 2008. [3] J. Kissel, R. Z. Sagdeev, J. L. Bertaux, V. N. Angarov, J. Audouze, J. E. Blamont, K. Buchler, E. N. Evlanov, H. Fechtig, M. N. Fomenkova, H. von Hoerner, N. A. Inogamov, V. N. Khromov, W. Knabe, F. R. Krueger, Y. Langevin, B. Leonasv, A. C. Levasseur-Regourd, G. G.Managadze, S. N. Podkolzin, V. D. Shapiro, S. R. Tabaldyev, and B. V. Zubkov. Com-position of comet Halley dust particles from VEGA observations. Nature, 321:280-282, May 1986. [4] D. Despois, J. Crovisier, D. Bockelee-Morvan, E. Gerard, and J. Schraml. Observations of hydrogen cyanide in comet halley. Astronomy and Astrophysics, 160:L11+, May 1986. [5] C. N. Matthews and R. D. Minard. Hydrogen cyanide polymers connect cosmochemistry and biochemistry. In IAU Symposium, volume 251 of IAU Symposium, pages 453-458, October 2008. [6] N. Sarker, A. Somogyi, J. I. Lunine, and M. A. Smith. Titan Aerosol Analogues: Analysis of the Nonvolatile Tholins. Astrobiology, 3:719-726, December 2003.

  15. High Precision 142Nd/144Nd and 143Nd/144Nd Isotope Ratio Measurements in Rock Samples

    Science.gov (United States)

    Ali, A.; Srinivasan, G.

    2009-05-01

    The long-lived 147Sm-143Nd system with a half-life (T1/2) of 106 Gyr is generally used for geochronology. The short-lived 146Sm-142Nd system (T1/2= 103 Myr) is used as a geological tracer to track early (˜500 Ma) silicate differentiation [1] events in different planetary bodies. The isotope composition measurements by thermal ionization mass spectrometry (TIMS) require purification of Nd using chemical separation methods. This is important as an impure sample will give both a very poor ion yield and cause beam instability in the mass spectrometer, potentially resulting in a poor analysis [2]. The separation of Nd for 143Nd isotope measurement is, fairly straightforward because there is no isobaric interference of any other REE. While 142Nd isotope analysis needs chemically separated Nd fraction to be ˜100% Ce-free as latter is composed of a substantial amount of 142Ce isotope. A 4-steps technique, modified from Caro et al., [3], for the separation of Nd is established at the Cosmochemistry Laboratory of University of Toronto, Canada and applied to the measurement of Nd isotope ratios in geological reference sample BCR-2 (USGS, Columbia River basalt) using TIMS. Results of the isotopic ratios obtained for BCR-2 are in good agreement with published values [e.g., 4]. Analytical work on the samples discovered as the oldest rocks on Earth [5] from Nuvvuagittuq greenstone belt in Québec, Canada and various meteorites is in progress. An account of the procedures involved is briefly described here. All working solutions and acids were prepared using >18.2 MΩ.cm-1 H2O from a Milli-Q water system. Experiments were performed under Class 100 clean work bench with acid-cleaned apparatus and plastic-ware. The whole rock powders were weighed (20-30 mg) and dissolved in a mixture of HF and HNO3 using PFA vials and heated at 110°C. Further decomposition was done in Teflon bomb in the oven at 205°C. Later on contents of the Teflon bomb were transferred to vials and fluorides

  16. Science at the ends of the Earth: astrobiology field expeditions as outreach tools

    Science.gov (United States)

    Billings, Linda

    paper will report on and evaluate communication, education, and outreach initiatives conducted in conjunction with ASTEP field campaigns, addressing the costs and benefits of linking students, teachers, and other interested citizens with researchers in the field. This paper will highlight success stories, lessons learned, and promising practices regarding educational programs in scientific research environments. SUMMARY The Astrobiology Program in NASA's Science Mission Directorate studies the origin, evolution, distribution, and future of life in the universe. Astrobiology research addresses three fundamental questions: How does life begin and evolve? Is there life beyond Earth and how can we detect it? What is the future of life on Earth and in the universe? Goals of the Astrobiology Program range from determining the nature and distribution of habitable environments in the Solar System and beyond to understanding the emergence of life from cosmic and planetary precursors, the interaction of past life on Earth with its changing environment, the formation and evolution of planets, links between planetary and biological evolution, the effects of climate and geology on habitability, and life's precursors and habitats in the outer solar system. Research dedicated to fulfilling these goals is conducted on Earth and in space, with a growing number of astrobiology investigations flying on planetary exploration missions. The field of astrobiology is an endeavor that brings together researchers in a broad range of disciplines including Earth and planetary science, astrophysics, heliophysics, microbiology and evolutionary biology, and cosmochemistry. Since 1995, the field of astrobiology has grown rapidly, and the pace of discovery has been brisk. The possibility of extraterrestrial life is now a serious scientific question. Research findings over the past decade that are relevant to this question include the controversial 1996 claim of fossil evidence for microbial life in a

  17. Thermal history of type-3 chondrites in the NASA antarctic collection

    Science.gov (United States)

    Bonal, L.; Quirico, E.; Montagnac, G.

    2014-07-01

    Chondrites are the most primitive meteorites. However, they were all modified in some ways by post-accretion geological processes operating on their asteroidal parent bodies. Hence, to decipher the formation(s) and origin(s) of their components, we must first understand how chondritic materials were modified in their asteroidal parent bodies. The modifications induced by secondary processes should not be underestimated and have to be precisely estimated before any interpretation of chondrite properties in terms of cosmochemistry. In particular, all chondrites contain some organic components that were potentially chemically and physically modified through post-accretion processes. A thin understanding of the induced evolution is required to allow for pertinent comparisons with other primitive extraterrestrial materials, such as cometary grains, to finally address questions such as the origin of organics in the Solar System. Type 3 chondrites experienced thermal metamorphism on their asteroidal parent body due to the radioactive decay of elements such as ^{26}Al. Temperatures higher than 300 °C were experienced on timescales of several thousands of years. Still, type 3 chondrites remain as unequilibrated rocks and common mineralogical thermometers cannot be applied. The polyaromatic carbonaceous matter is sensitive to thermal episodes (of long and short duration) experienced by the host meteorite. In particular, its structural order directly reflects the thermal history experienced on their parent bodies. The structural modification of the aromatic carbonaceous matter towards a higher order is irreversible, and independent of the mineralogy and degree of aqueous alteration. It is mainly controlled by the peak metamorphic temperature. Moreover, under the assumption of fairly similar organic precursors among chondrites of distinct groups, the structural order of polyaromatic organic matter allows for a direct comparison of their metamorphic grades. It is then possible

  18. Foreword

    Science.gov (United States)

    Jorissen, A.; Goriely, S.; Rayet, M.; Siess, L.; Boffin, H.

    performed using a radioactive ion beam technique, a new and powerful tool of investigation in nuclear astrophysics, which has since been developed worldwide. The second program, “Nuclear Astrophysics: measurement, evaluation and compilation of reaction rates, and their impact on stellar evolution and nucleosynthesis" (1992 1997), gave the scientific community the first European compilation of astrophysical reaction rates. This work was meant to supersede the compilations performed during more than forty years by a team led by the late Nobel Prize winner, William A. Fowler, at the California Institute of Technology. A relentless scientific advisor amongst astrophysicists as well as nuclear physicists, Marcel deplores the persistent lack of communication between those two communities. For years, his hope has been to see the rise of a generation of true astronuclear physicists, but one has to admit with him that this goal is far from being achieved yet and that one still has to fight, despite all the expressions of good intentions, against the barriers that, as is usual, separate scientific disciplines. It is therefore in tribute to the transdisciplinary and visionary nature of Marcel Arnould's scientific work that his close collaborators at the IAA decided to organize this conference, which is explicitely devoted to future developments in the field of astronuclear physics and not, as is often the case, to already completed, or even published, works. The audience has been limited from the start to invited participants chosen for the quality of their human and scientific relations with Marcel, as well as for their contribution to the domains he is exceptionally found of. The conference program was on purpose centered on a few fields that for many years now have been central to the activities of the IAA: the stellar nucleosynthesis and its relations to stellar physics, to nuclear physics and to cosmochemistry. The organizers' choice was to concentrate on a few challenging

  19. Uranium isotopic compositions of the crust and ocean: Age corrections, U budget and global extent of modern anoxia

    Science.gov (United States)

    Tissot, François L. H.; Dauphas, Nicolas

    2015-10-01

    the variability of the 238U/235U ratio on Pb-Pb and U-Pb ages and provide analytical formulas to calculate age corrections as a function of the age and isotopic composition of the sample. The crustal ratio may be used in calculation of Pb-Pb and U-Pb ages of continental crust rocks and minerals when the U isotopic composition is unknown. In cosmochemistry, the search for 247Cm (t1/2 = 15.6 Myr), an extinct short-lived radionuclide that decays into 235U, is important for understanding how r-process nuclides were synthesized in stars and learning about the astrophysical context of solar system formation (Chen and Wasserburg, 1981; Wasserburg et al., 1996; Nittler and Dauphas, 2006; Brennecka et al., 2010b; Tissot et al., 2015). In both terrestrial and extraterrestrial samples, variations in the 238U/235U ratio affect Pb-Pb ages (and depending on the analytical protocols, U-Pb ages). Therefore, samples dated by these techniques need to have their U isotopic compositions measured (Stirling et al., 2005, 2006; Weyer et al., 2008; Amelin et al., 2010; Brennecka et al., 2010b; Brennecka and Wadhwa, 2012; Connelly et al., 2012; Goldmann et al., 2015) or uncertainties on the U isotopic composition should be propagated into age calculations. In low temperature aqueous geochemistry, U isotopic fractionation between U4+ and U6+ (driven in part by nuclear field shift effects; Bigeleisen, 1996; Schauble, 2007; Abe et al., 2008), makes U isotopes potential tracers of paleoredox conditions (Montoya-Pino et al., 2010; Brennecka et al., 2011a; Kendall et al., 2013, 2015; Asael et al., 2013; Andersen et al., 2014; Dahl et al., 2014; Goto et al., 2014; Noordmann et al., 2015). The present paper aims at constraining some aspects of the global budget of uranium in the modern oceans using 238U/235U isotope variations, which involves characterizing the U isotopic composition of seawater and several reservoirs involved in the uranium oceanic budget. Uranium can exist in two oxidation states

  20. Terrestrial microbes in martian and chondritic meteorites

    Science.gov (United States)

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

    2007-08-01

    NASA Cosmochemistry grant, ( P. I. Thiemens).