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Sample records for igneous processes relevant

  1. Is phosphorus predictably incompatible in igneous processes?

    NASA Technical Reports Server (NTRS)

    Goodrich, C. A.; Barnes, S.

    1984-01-01

    Siderophile element abundances are central to recent models for core formation in the Earth and Moon and the origin of the Moon. It is important to identify siderophile elements whose behavior in igneous processes is predictable, so that primary mantle abundances can be deduced by subtracting out the effects of igneous processes. Newsom's model for core formation in the Moon requires subchondritic P, and suggests that P was depleted due to volatility. Experiments were conducted to determine P olivine/liquid distribution coefficients. Preliminary results indicate that P can be compatible with olivine during rapid cooling, but is not during isothermal crystallization with long growth times, and tends to be expelled during annealing. It is therefore not likely that P is compatible under any widespread igneous conditions, and the incompatible behavior of P in lunar crustal rocks can be safety assumed. In addition, low fO2 is insufficient to cause P compatibility, so it is unlikely that P-rich silicates formed during the early evolution of the Earth or Moon. These results indicate that P is depleted in the Moon.

  2. Volcanism and igneous processes in small icy satellites

    NASA Technical Reports Server (NTRS)

    Stevenson, D. J.

    1982-01-01

    Evidence for the production of endogenic processes of the small Saturnian satellites by igneous activity of low melting point NH3-H2O magma heated radiogenically is presented. An initial state of the inner satellites is modeled as a homogeneous mixture of particulate silicates and ices. Conductive transport is assumed to have either combined with heat capacity in a mixture of crystalline phases, or to have been reduced by the presence of dust, defects, vitreous or amorphous phases, and clathrates. The extent to which a eutectic melt could form is calculated in terms of the volume percentage of melt, with all heating above 175 K going toward overcoming the latent heat of the eutectic mix. Mimas and Enceladus were treated as free from radiogenic heat sources, which were significant for Tethys, Dione, Rhea, and Iapetus. The migrations of inner materials to form surface structures and seal off the interiors of the moons are described.

  3. The behaviour of copper isotopes during igneous processes

    NASA Astrophysics Data System (ADS)

    Savage, P. S.; Moynier, F.; Harvey, J.; Burton, K. W.

    2015-12-01

    Application of Cu isotopes to high temperature systems has recently gained momentum and has the potential for probing sulphide fractionation during planetary differentiation [1]. This requires robust estimates for planetary reservoirs, and a fundamental understanding of how igneous processes affect Cu isotopes; this study aims to tackle the latter. Cogenetic suites affected by both fractionation crystallisation and cumulate formation were analysed to study such effects on Cu isotopes. In S-undersatured systems, Cu behaves incompatibly during melt evolution and the Cu isotope composition of such melt is invariant over the differentiation sequence. In contrast, S-saturated systems show resolvable Cu isotope variations relative to primitive melt. Such variations are minor but imply a slightly heavy Cu isotope composition for continental crust compared to BSE, consistent with granite data [2]. Although olivine accumulation does not affect Cu isotopes, spinel-hosted Cu is isotopically light relative to the bulk. Analysis of variably melt-depleted cratonic peridotites shows that partial melting can affect Cu isotope composition in restite, with the depleted samples isotopically light compared to BSE. This could be due to residual spinel and/or incongruent melting of sulphides - individual sulphides picked from a single xenolith reveal a range of Cu isotope compositions, dependent on composition. Although partial melting may fractionate Cu isotopes, models suggest most mantle-derived melt will have δ65Cu ≈ BSE, as most source Cu will be transferred to the melt. Small degree melts such as ocean island basalts are predicted to be isotopically heavier than MORB, if derived from a primitive mantle source. OIBs have a range of Cu isotope compositions: some are heavier than MORB as predicted; however, some have much lighter compositions. Since Cu isotopes can be significantly fractionated in the surface environment [e.g. 3] OIB Cu isotopic variations may be linked to

  4. Crustal structure and igneous processes in a chondritic Io

    NASA Technical Reports Server (NTRS)

    Kargel, J. S.

    1993-01-01

    Liquid sulfur can form when metal-free C1 or C2 chondrites are heated. It may be obtained either by direct melting of native sulfur in disequilibrated C1 or C2 chondrites or by incongruent melting of pyrite and other sulfides in thermodynamically equilibrated rocks of the same composition. Hence, Lewis considered C2 chondrites to be the best meteoritic analog for Io's bulk composition. Metal-bearing C3 and ordinary chondrites are too chemically reduced to yield liquid sulfur and are not thought to represent plausible analogs of Io's bulk composition. An important aspect of Lewis' work is that CaSO4 and MgSO4 are predicted to be important in Io. Real C1 and C2 chondrites contain averages of, respectively, 11 percent and 3 percent by mass of salts (plus water of hydration). The most abundant chondritic salts are magnesium and calcium sulfates, but other important components include sulfates of sodium, potassium, and nickel and carbonates of magnesium, calcium, and iron. It is widely accepted that chondritic salts are formed by low-temperature aqueous alteration. Even if Io originally did not contain salts, it is likely that aqueous alteration would have yielded several percent sulfates and carbonates. In any event, Io probably contains sulfates and carbonates. This report presents the results of a model of differentiation of a simplified C2 chondrite-like composition that includes 1.92 percent MgSO4, 0.56 percent CaSO4, 0.53 percent CaCO3, and 0.094 percent elemental sulfur. The temperature of the model is gradually increased; ensuing fractional melting results in these components extruding or intruding at gravitationally stable levels in Io's crust. Relevant phase equilibria were reviewed. A deficiency of high-pressure phase equilibria renders the present model qualitative.

  5. Igneous processes and dike swarms: Magnetic signatures in the Solar System

    NASA Astrophysics Data System (ADS)

    Purucker, M. E.

    2015-12-01

    Large igneous provinces (LIP) are common in planetary environments: at Mars, Venus, Mercury, Io, and of course the Earth and its Moon. Dike swarms are often associated with LIPs, and are one of the only remaining signatures of a LIP in old, eroded settings. On Earth, dike swarms are often recognized by their magnetic signatures. The World Digital Magnetic Anomaly Map (version 2, 2015) is now based on a higher resolution 5 km grid, so many more dike swarms are apparent. We review this latest compilation. Several new high resolution planetary magnetic data sets have also recently become available, and we review evidence for igneous processes, and dikes, in these new data sets. We also review the prospect for new planetary magnetic data sets that might further elucidate igneous processes. At Mars, for example, we have photogeologic evidence for a host of dike swarms, but because of the high altitude of the magnetic data sets, no magnetic evidence exists. A new technique based on remotely sensing the magnetic field of the atomic Na in micro-meteorite ablation layers offers the promise of improving the spatial resolution by a factor of 2-4 at Mars.

  6. Classification of mafic clasts from mesosiderites: Implications for endogenous igneous processes

    SciTech Connect

    Rubin, A.E. ); Mittlefehldt, D.W. )

    1992-02-01

    The authors have analyzed thirteen igneous pebbles from the Vaca Muerta, EET87500, and Bondoc mesosiderites by electron microprobe and instrumental neutron activation and combined these data with literature data for forty-three analyzed mesosiderite clasts. They classify these well-characterized clasts into the following five principal groups: (1) Polygenic and monogenic cumulates (39%) are coarse-grained gabbros that are highly depleted in incompatible elements (relative to H chondrites); they formed at moderate depth either as residues of low-degree partial melting of pre-existing cumulate eucrites or as cumulates from parent melts similar to cumulate eucrites. (2) Polygenic basalts (30%) are finer-grained rocks with positive europium anomalies, La/Lu ratios < 1, and lower rare earth element abundances than basaltic eucrites. It seems likely that these rocks were formed near their parent body surface by remelting mixtures of major amounts of basaltic eucrites and lesser amounts of cumulate eucrites. (3) Quench-textured rocks comprise two compositional groups, (a) those which resemble basaltic eucrites (5%), and (b) those which resemble cumulate eucrites (2%). The quench-textured rocks are probably monogenic; they formed most likely when small-scale impacts at their parent body surface totally melted small amounts of basaltic or cumulate eucrite material. (4) Monogenic basalts (11%) resemble basaltic eucrites and formed by endogenous igneous processes on the mesosiderite parent body (MPB). (5) Ultramafic rocks are cumulates consisting mainly of large crystals of orthopyroxene (9%) or olivine (4%). Orthopyroxenite clasts closely resemble diogenites and were formed most likely by endogenous igneous processes.

  7. The role of igneous and metamorphic processes in triggering mass extinctions and Earth crises

    NASA Astrophysics Data System (ADS)

    Svensen, Henrik; Planke, Sverre; Polozov, Alexander G.; Jerram, Dougal; Jones, Morgan T.

    2016-04-01

    Mass extinctions and transient climate events commonly coincide in time with the formation of Large igneous provinces (LIPs). The end-Permian event coincides with the Siberian Traps, the end-Triassic with the Central Atlantic Magmatic Event (CAMP), the Toarcian with the Karoo LIP, and the Paleocene-Eocene Thermal Maximum (PETM) with the North Atlantic Igneous Province. Although the temporal relationship between volcanism and the environmental crises has been known for decades, the geological processes linking LIPs to these environmental events are strongly debated: Explosive LIP volcanism should lead to short term cooling (not long term warming), mantle CO2 is too 13C-enriched to explain negative 13C carbon isotope excursions from sedimentary sequences, the LIP volcanism is poorly dated and apparently lasts much longer that the associated environmental events, large portions of the LIPs remain poorly explored, especially the sub-volcanic parts where sills and dikes are emplaced in sedimentary host rocks, and thus gas flux estimates from contact aureoles around sill intrusions are often poorly constrained. In this presentation, we discuss the status of LIP research with an emphasis on the sub volcanic processes. We show that potential for degassing of greenhouse gases, aerosols, and ozone destructive gases is substantial and can likely explain the triggering of both climatic events and mass extinctions.

  8. Evolutionary relevance facilitates visual information processing.

    PubMed

    Jackson, Russell E; Calvillo, Dusti P

    2013-01-01

    Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing. PMID:24184882

  9. Classification of mafic clasts from mesosiderites - Implications for endogenous igneous processes

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Mittlefehldt, David W.

    1992-01-01

    Results are presented from an analysis of 13 igneous pebbles from the Vaca Muerta, EET87500, and Bondoc mesosiderites, using electron microprobe and instrumental neutron activation techniques. These data, combined with literature data on compositions of 43 mesosiderite clasts were used to compile a classification scheme for the various types of mafic silicate clasts that occur in mesosiderites. These clasts were classified into five principal groups: (1) polygenic and monogenic cumulates (30 percent); (2) polygenic basalts (30 percent); (3) quench-textured rocks, comprising two compositional subgroups (those which resemble basaltic eucrites (5 percent), and those which resemble cumulate eucrites (2 percent)); (4) monogenic basalts (11 percent); and (5) ultramafic rocks, consisting mainly of large crystals of orthopyroxene (9 percent) or olivine (4 percent). The conditions under which these clasts were formed are discussed.

  10. Interactions of tectonic, igneous, and hydraulic processes in the North Tharsis Region of Mars

    NASA Technical Reports Server (NTRS)

    Davis, P. A.; Tanaka, Kenneth L.; Golombek, M. P.; Plescia, J. B.

    1991-01-01

    Recent work on the north Tharsis of Mars has revealed a complex geologic history involving volcanism, tectonism, flooding, and mass wasting. Our detailed photogeologic analysis of this region found many previously unreported volcanic vents, volcaniclastic flows, irregular cracks, and minor pit chains; additional evidence that volcanic tectonic processes dominated this region throughout Martian geologic time; and the local involvement of these processes with surface and near surface water. Also, photoclinometric profiles were obtained within the region of troughs, simple grabens, and pit chains, as well as average spacings of pits along pit chains. These data were used together with techniques to estimate depths of crustal mechanical discontinuities that may have controlled the development of these features. In turn, such discontinuities may be controlled by stratigraphy, presence of water or ice, or chemical cementation.

  11. Igneous vs impact processes for the origin of the Mare lavas

    NASA Technical Reports Server (NTRS)

    Gornitz, V.

    1973-01-01

    The respective role of external vs internal processes is considered. The inner Orientale basin was formed by the explosive impact of an asteroidal body. Within minutes after the impact, the concentric fracture system developed as an adjustment to the stresses generated by the shock wave. Examples are presented to illustrate that the upwelling of lava in the center of Mare Orientale and several craters on its ejecta blanket occurred well after the asteroidal collision which generated the bulls-eye structure. Thus, the lavas were not strictly impact melts. However, a close relationship may have existed between the impact and subsequent volcanism.

  12. Silicon isotopes in granulite xenoliths: Insights into isotopic fractionation during igneous processes and the composition of the deep continental crust

    NASA Astrophysics Data System (ADS)

    Savage, Paul S.; Georg, R. Bastian; Williams, Helen M.; Halliday, Alex N.

    2013-03-01

    The silicon (Si) cycle is of great current interest but the isotopic composition of the continental crust has not been determined. Magmatic differentiation generates liquids with heavier Si and the lower crust, thought to be dominated by cumulates and restites, is predicted to have a light isotopic composition. This is borne out by the composition of many types of granite, which appear to have relative light Si for their silica content. Here we report the Si isotopic compositions of two granulite facies xenolith suites, from the Chudleigh and McBride volcanic provinces, Australia, providing new constraints on deep crustal processes and the average composition of the deep continental crust. The xenoliths display a range of isotopic compositions (δ30Si=-0.43‰ to -0.15‰) comparable to that measured previously for igneous rocks. The isotopic compositions of the McBride xenoliths reflect assimilation and fractional crystallisation (AFC) and/or partial melting processes. Silicon and O isotopes are correlated in the McBride suite and can be explained by AFC of various evolved parent melts. In contrast, the Chudleigh xenoliths have Si isotope compositions predominantly controlled by the specific mineralogy of individual cumulates. Using the xenolith data and a number of weighting methods, the Si isotope compositions of the lower and middle crust are calculated to be δ30Si=-0.29±0.04‰ (95% s.e.) and -0.23±0.04‰ (95% s.e.) respectively. These values are almost identical to the composition of the Bulk Silicate Earth, implying minimal isotope fractionation associated with continent formation and no light lower crustal reservoir.

  13. Igneous and shock processes affecting chassignite amphibole evaluated using chlorine/water partitioning and hydrogen isotopes

    NASA Astrophysics Data System (ADS)

    Giesting, Paul A.; Schwenzer, Susanne P.; Filiberto, Justin; Starkey, Natalie A.; Franchi, Ian A.; Treiman, Allan H.; Tindle, Andy G.; Grady, Monica M.

    2015-03-01

    Amphibole in chassignite melt inclusions provides valuable information about the volatile content of the original interstitial magma, but also shock and postshock processes. We have analyzed amphibole and other phases from NWA 2737 melt inclusions, and we evaluate these data along with published values to constrain the crystallization Cl and H2O content of phases in chassignite melt inclusions and the effects of shock on these amphibole grains. Using a model for the Cl/OH exchange between amphibole and melt, we estimate primary crystallization OH contents of chassignite amphiboles. SIMS analysis shows that amphibole from NWA 2737 currently has 0.15 wt% H2O. It has lost ~0.6 wt% H2O from an initial 0.7-0.8 wt% H2O due to intense shock. Chassigny amphibole had on average 0.3-0.4 wt% H2O and suffered little net loss of H2O due to shock. NWA 2737 amphibole has δD ≈ +3700‰; it absorbed Martian atmosphere-derived heavy H in the aftermath of shock. Chassigny amphibole, with δD ≤ +1900‰, incorporated less heavy H. Low H2O/Cl ratios are inferred for the primitive chassignite magma, which had significant effects on melting and crystallization. Volatiles released by the degassing of Martian magma were more Cl-rich than on Earth, resulting in the high Cl content of Martian surface materials.

  14. Kinetics of crystallization of igneous rocks

    SciTech Connect

    Kirkpatrick, R.J.

    1981-01-01

    The geochemistry of igneous rocks is discussed, with the primary objectives of bringing together the theories underlying the kinetics of crystallization of igneous rocks and illustrating the use of these theories in understanding experimental and observational data. The primary purpose of the chapter is to introduce current thinking about the kinetics of igneous rocks and to provide a basis for understanding other work. A basic assumption made in the discussion is that the rate of any chemical reaction, including the crystallization of igneous rocks, is zero at equilibrium and proceeds at a finite rate only at a finite deviation from equilibrium. As such, an understanding of the processes operating in igneous rocks requires an understanding of how deviation from equilibrium affects the rates and mechanisms of the processes occurring during crystallization. These processes are detailed, with special emphasis given to nucleation and crystal growth. (JMT)

  15. Relevance and Goal-Focusing in Text Processing

    ERIC Educational Resources Information Center

    McCrudden, Matthew T.; Schraw, Gregory

    2007-01-01

    This article reviews the role of relevance in text processing. It argues that relevance instructions provided by instructors and texts help readers identify text segments that are germane to a reading goal. A taxonomy of relevance instructions is presented and four basic types of relevance manipulations are considered (i.e., targeted segments,…

  16. Rates and processes of crystal growth in the system anorthite-albite. [magmatic liquids in igneous rock formation

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, R. J.; Klein, L.; Uhlmann, D. R.; Hays, J. F.

    1979-01-01

    The growth rates and interface morphologies of crystals of synthetic compositions in the anorthite (CaAl2Si2O8)-albite (NaAlSi3O8) plagioclase feldspar system are measured in an investigation of the crystallization of igneous rocks. Mixed plagioclase glasses with compositions of 75% and 50% anorthite were observed using the microscope heating technique as they crystallized at temperatures near the liquidus, and 75%, 50% and 20% anorthite crystals were treated by resistance heating and observed at greater degrees of undercooling. Growth rates were found to be independent of time and to decrease with increasing albite content, ranging from 0.5 to 2 x 10 to the -5th cm/min. The crystal morphologies for all compositions are faceted near the liquidus and become progressively skeletal, dendritic and fibrillar with increasing undercooling.

  17. Graphene nanoribbons: Relevance of etching process

    SciTech Connect

    Simonet, P. Bischoff, D.; Moser, A.; Ihn, T.; Ensslin, K.

    2015-05-14

    Most graphene nanoribbons in the experimental literature are patterned using plasma etching. Various etching processes induce different types of defects and do not necessarily result in the same electronic and structural ribbon properties. This study focuses on two frequently used etching techniques, namely, O{sub 2} plasma ashing and O{sub 2 }+ Ar reactive ion etching (RIE). O{sub 2} plasma ashing represents an alternative to RIE physical etching for sensitive substrates, as it is a more gentle chemical process. We find that plasma ashing creates defective graphene in the exposed trenches, resulting in instabilities in the ribbon transport. These are probably caused by more or larger localized states at the edges of the ashed device compared to the RIE defined device.

  18. Origins of Igneous Layering

    NASA Astrophysics Data System (ADS)

    Marsh, Bruce

    Anyone who has ever seen a photo of a layered intrusion, let alone visited one first hand, or even seen a thin section from one, cannot help but be impressed by the stunning record of crystal growth and deposition. Such bodies stand as majestic monuments of undeniable evidence that intricate magmatic processes exist, processes that couple crystallization, convection, and crystal sorting to form rocks so highly ordered and beautiful that they are a wonder to behold. These are the altars to which petrologists must carry their conceived petrologic processes for approval.Although significant in number, the best layered intrusions seem to be found almost always in remote places. Their names, Bushveld, Muskox, Kiglapait, Stillwater, Duke Island, Skaergaard, Rhum, ring through igneous petrology almost as historic military battles (Saratoga, Antietam, Bull Run, Manassas, Gettysburg) do through American history. People who have worked on such bodies are almost folk heros: Wager, Deer, Brown, Jackson, Hess, Irvine, McBirney, Morse; these names are petrologic household words. Yet with all this fanfare and reverence, layered instrusions are nearly thought of as period pieces, extreme examples of what can happen, but not generally what does. This is now all changing with the increasing realization that these bodies are perhaps highly representative of all magmatic bodies. They are simply more dynamically complete, containing more of the full range of interactions, and of course, exposing a more complete record. They are one end of a spectrum containing lava flows, lava lakes, large sills, plutons, and layered intrusions. This book uniquely covers this range with an abundance of first-hand field observations and a good dose of process conceptualization, magma physics, and crystal growth kinetics.

  19. Insights into Igneous Geochemistry from Trace Element Partitioning

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Hanson, B. Z.

    2001-01-01

    Partitioning of trivalent elements into olivine are used to explore basic issues relevant to igneous geochemistry, such as Henry's law. Additional information is contained in the original extended abstract.

  20. Magmas and magmatic rocks: An introduction to igneous petrology

    SciTech Connect

    Middlemost, E.A.K.

    1986-01-01

    This book melds traditional igneous petrology with the emerging science of planetary petrology to provide an account of current ideas on active magmatic and volcanic processes, drawing examples from all igneous provinces of the world as well as from the moon and planets. It reviews the history and development of concepts fundamental to modern igneous petrology and includes indepth sections on magmas, magnetic differentiation and volcanology.

  1. Microscopic tubes in igneous rocks

    NASA Technical Reports Server (NTRS)

    Richter, D.; Simmons, G.

    1977-01-01

    Microscopic tubes have been observed in several igneous rocks and may be quite common. They occur in single crystals and have either elliptical or circular cross-sections 1 to 5 microns in diameter and are ten to hundreds of microns long. Microtubes may be hollow or partially or completely filled with another phase, but are distinct from acicular crystals of accessory minerals such as rutile. Microtubes can form by at least three processes: (1) the partial annealing of microcracks, (2) the natural etching of dislocations, or (3) the primary inclusion of fluid material during crystal growth.

  2. Alkaline igneous rocks

    SciTech Connect

    Fitton, J.G.; Upton, B.G.J.

    1987-01-01

    In this volume, an international team of scientists provides an up-to-date overview of the nature, origin, and evolution of alkaline magmas. Particular attention is paid to carbonatites, lamprophyres, and lamproites which are rock suites of current interest not recently reviewed elsewhere. Recent work on the classical alkaline provinces of East Africa, South Greenland, and the Kola Peninsula is included together with reviews of other areas of alkaline magmatism in North and South America, East Greenland, Europe, West Africa, and the ocean basins. Other papers discuss the impact of experimental isotopic and geochemical studies of the petrogenesis of alkaline rocks. This book will be of interest to petrologists and geochemists studying alkaline igneous rocks, and to other earth scientists as a reference on the rapidly expanding field of igneous petrology.

  3. Theoretical petrology. [of igneous and metamorphic rocks

    NASA Technical Reports Server (NTRS)

    Stolper, E.

    1979-01-01

    In the present paper, some areas of growing interest in the American efforts in petrology during the 1975-1978 quadrennium are reviewed. In igneous petrology, studies of structures and thermodynamic properties of silicate melts and of kinetics of igneous processes are in a period of rapid growth. Plate tectonic concepts have had (and will no doubt continue to have) an important influence by focusing interest on specific problems and by providing a framework for the understanding of petrogenesis. An understanding of mantle processes and evolution through the integration of petrological, geophysical, and geochemical constraints has been developed over the past 20 years, and will undoubtedly provide direction for future petrological studies.

  4. Relevance as Process: Judgements in the Context of Scholarly Research

    ERIC Educational Resources Information Center

    Anderson, Theresa Dirndorfer

    2005-01-01

    Introduction: This paper discusses how exploring the research process in-depth and over time contributes to a fuller understanding of interactions with various representations of information. Method. A longitudinal ethnographic study explored decisions made by two informants involved in scholarly research. Relevance assessment and information…

  5. Do Specific Relevance Instructions Promote Transfer Appropriate Processing?

    ERIC Educational Resources Information Center

    McCrudden, Matthew T.

    2011-01-01

    This study examined whether specific relevance instructions affect transfer appropriate processing. Undergraduates (n = 52) were randomly assigned to one of three pre-reading question conditions that asked them what-questions, why-questions, or to read for understanding (i.e., control condition). There were no differences in reading time across…

  6. Geochemistry of 2-4-mm particles from Apollo 14 soil (14161) and implications regarding igneous components and soil-forming processes

    NASA Technical Reports Server (NTRS)

    Jolliff, B. L.; Korotev, R. L.; Haskin, L. A.

    1991-01-01

    The present paper describes the compositional systematics of 381 particles analyzed from 14161, which was taken near the lunar module as part of the bulk sample. Attention is given to the distribution of lithologies, based on petrographic examination and compositions determined by INAA, and to implications of the compositions of polymict particles regarding igneous precursors and soil-forming processes. It was found that the most abundant particles are the impact-melt lithologies and regolith and fragmental breccias. The mean composition of the entire suite of 2-4-mm particles differs from that of the associated less-than-1-mm fines by having higher concentrations of incompatible trace elements and Na2O, and a lower concentration of CaO. There is a subset of regolith breccia particles and agglutinates in the 2-4-mm particles that have nearly identical compositions and Is/FeO similar to those of the less-than-1-mm fines. It is suggested that these particles are constructional products formed from the local regolith rather than comminuted fragments of ancient regolith breccias.

  7. Ureilites are not igneous differentiates

    NASA Technical Reports Server (NTRS)

    Clayton, Robert N.; Mayeda, Toshiko K.

    1988-01-01

    Although most all meteorites are as old as the solar system (4.5 billion years), they can be subdivided into primitive and evolved groups, depending on the extent of their chemical and physical processing. Primitive meteorites, most of which are chondrites, are assemblages of dust and millimeter-sized pellets from the presolar nebula, which were not extensively heated and processed since their assembly. Thus they provide information about the conditions in the nebular cloud. Many of the evolved meteorites are achondrites, which are igneous rocks produced by melting on or within an asteroidal object known as the parent body. A major unsolved problem in solar system studies is identification of the source of heat which led to melting of the achondrites. The role of oxygen isotopes in establishing genetic relationships among meteorites is examined.

  8. Diapiric transfer of melt in Kilauea Iki lava lake, Hawaii: a quick, efficient process of igneous differentiation

    USGS Publications Warehouse

    Helz, R.T.; Kirschenbaum, H.; Marinenko, J.W.

    1989-01-01

    Kilauea Iki lava lake, formed in 1959, is a large pond of picritic basalt (average MgO content = 15.34% by weight), which has cooled and crystallized as a small, self-roofed magma chamber. Differentiation processes recognized as active in the lake include rather inefficient settling of the larger (2-10 mm) olivine phenocrysts, formation of segregation veins, and formation of diapir-like vertical olivine-rich bodies, all processes which occur in one or more of the other Kilauean lava lakes as well. In addition, most of the central part of Kilauea Iki has been affected by diapiric melt transfer. Diapiric melt transfer was active from 1960 to 1971 and has affected most of the central part of the lake from 13 m to at least 80 m. The process ran simultaneously with the other three main differentiation processes but started and stopped independently of the others. Calculations suggest that between 21 and 42 wt % liquid has been extracted from the depleted zone at 56-78 m in the center of the lake, making this a very efficient process of chemical differentiation. -from Authors

  9. Adaptive memory: evaluating alternative forms of fitness-relevant processing in the survival processing paradigm.

    PubMed

    Sandry, Joshua; Trafimow, David; Marks, Michael J; Rice, Stephen

    2013-01-01

    Memory may have evolved to preserve information processed in terms of its fitness-relevance. Based on the assumption that the human mind comprises different fitness-relevant adaptive mechanisms contributing to survival and reproductive success, we compared alternative fitness-relevant processing scenarios with survival processing. Participants rated words for relevancy to fitness-relevant and control conditions followed by a delay and surprise recall test (Experiment 1a). Participants recalled more words processed for their relevance to a survival situation. We replicated these findings in an online study (Experiment 2) and a study using revised fitness-relevant scenarios (Experiment 3). Across all experiments, we did not find a mnemonic benefit for alternative fitness-relevant processing scenarios, questioning assumptions associated with an evolutionary account of remembering. Based on these results, fitness-relevance seems to be too wide-ranging of a construct to account for the memory findings associated with survival processing. We propose that memory may be hierarchically sensitive to fitness-relevant processing instructions. We encourage future researchers to investigate the underlying mechanisms responsible for survival processing effects and work toward developing a taxonomy of adaptive memory. PMID:23585858

  10. Adaptive Memory: Evaluating Alternative Forms of Fitness-Relevant Processing in the Survival Processing Paradigm

    PubMed Central

    Sandry, Joshua; Trafimow, David; Marks, Michael J.; Rice, Stephen

    2013-01-01

    Memory may have evolved to preserve information processed in terms of its fitness-relevance. Based on the assumption that the human mind comprises different fitness-relevant adaptive mechanisms contributing to survival and reproductive success, we compared alternative fitness-relevant processing scenarios with survival processing. Participants rated words for relevancy to fitness-relevant and control conditions followed by a delay and surprise recall test (Experiment 1a). Participants recalled more words processed for their relevance to a survival situation. We replicated these findings in an online study (Experiment 2) and a study using revised fitness-relevant scenarios (Experiment 3). Across all experiments, we did not find a mnemonic benefit for alternative fitness-relevant processing scenarios, questioning assumptions associated with an evolutionary account of remembering. Based on these results, fitness-relevance seems to be too wide-ranging of a construct to account for the memory findings associated with survival processing. We propose that memory may be hierarchically sensitive to fitness-relevant processing instructions. We encourage future researchers to investigate the underlying mechanisms responsible for survival processing effects and work toward developing a taxonomy of adaptive memory. PMID:23585858

  11. A New Model for U-Series Isotope Fractionation During Igneous Processes, With Finite Diffusion and Multiple Solid Phases

    NASA Astrophysics Data System (ADS)

    van Orman, J.; Saal, A.; Bourdon, B.; Hauri, E.

    2002-12-01

    U-series radioactive disequilibria in basaltic lavas have been used to infer many important aspects of melt generation and extraction processes, including the porosity of the melting zone, the mantle upwelling rate, and the melt transport rate. These inferences are based on simplified models for the fractionation of U-series isotopes during melting and melt transport. The commonly used "dynamic melting" and "equilibrium porous flow" models neglect solid-state diffusion and do not consider the influence of multiple solid phases on the initial distribution and subsequent fractionation of U-series isotopes. These factors can be very important, particularly for 226Ra which has a short half-life (~1600 yrs) and is strongly partitioned into minerals like plagioclase, amphibole, and mica while being almost perfectly excluded from clinopyroxene and garnet, the major U and Th bearing minerals in peridotite. Ignoring diffusion and multi-phase effects can lead to conclusions about the melting process that have no basis in reality. We have developed a numerical model that takes into account the effects of solid-state diffusion and considers the distribution of U-series isotopes among multiple solid phases and melt at each step of the melting process. In an undisturbed rock in secular equilibrium, daughter isotopes will tend to be transferred among the component phases until they reach a steady state in which diffusive fluxes are balanced by radioactive production and decay. In general the individual minerals will be neither in secular equilibrium (on the equiline) nor in partitioning equilibrium with each other (on a horizontal line on the equiline diagram), unless diffusion is very slow or very fast relative to the daughter decay rate. We start with an arbitrary distribution of daughter isotopes among the phases in the system, then turn on diffusion and allow isotopes to redistribute themselves until the steady state is reached (on a time scale comparable to the half-life of

  12. Major compositional provinces on Mars: a record of igneous processes and H2O-rock interactions

    NASA Astrophysics Data System (ADS)

    Rogers, D.; Hamilton, V. E.

    2011-12-01

    The spatial distribution of surface compositions provides critical information needed to understand the formation of Martian crustal materials as well as the interactions between the surface, atmosphere, and hydrosphere. To this end, we present a new global map of major compositional provinces on Mars. The map was derived by applying statistical methods to new mineral distributions derived from Mars Global Surveyor Thermal Emission Spectrometer (TES) data. The new mineral distributions [1] were calculated using a larger set of olivine and pyroxene compositions, and at a higher spatial resolution (8 pixels per degree), relative to previous global studies [e.g, 2]. Consistent with previous results [2], we find that: A) Syrtis Major and circum-Tharsis volcanic plains are compositionally distinct from other, older highland surfaces, B) lowland materials exhibit elevated abundance of "high-silica" phases (amorphous silica and/or poorly crystalline silicates), and C) northern Acidalia surfaces are compositionally distinct from those in southern Acidalia. New findings include the following: D) northwestern Syrtis Major shield materials are enriched in feldspar relative to southern Syrtis Major, E) within Thaumasia and Aonium Plana (Hesperian aged plains), there are possibly 3 different classes of mineral assemblage, and F) heavily cratered Noachian terrains including Terra Meridiani, Tyrrhena Terra, and Cimmeria Terra can be divided into at least two classes based on relative abundance of plagioclase and low-Ca pyroxene. These new reported classes exhibit spatial coherency over a scale of at least tens of km; select areas were verified using spectral ratios from individual TES orbits that cross compositional class boundaries. These spatial trends in mineral assemblage may partially reflect global variations in melt generation and magmatic processes, and may also partially reflect spatial variation in precipitation, erosion, and/or ice-related alteration. For example, the

  13. Experimental studies of reactions relevant for γ-process nucleosynthesis

    SciTech Connect

    Scholz, P.; Endres, J.; Hennig, A.; Mayer, J.; Netterdon, L.; Zilges, A.; Sauerwein, A.

    2014-05-09

    We report on our recent experimental studies of reactions relevant for the γ process nucleosynthesis. Applying the activation method using the Cologne Clover Counting Setup total cross sections of the reactions {sup 168}Yb(α,γ), {sup 168}Yb(α,n), and {sup 187}Re(α,n) could be obtained. Furthermore, the reaction {sup 89}Y(p,γ) was investigated via the in-beam technique with HPGe detectors at the high-efficiency g-ray spectrometer HORUS in Cologne in order to determine partial and total cross sections.

  14. Aspects of two corrosion processes relevant to military hardware

    SciTech Connect

    Braithwaite, J.W.; Buchheit, R.G.

    1997-11-01

    Corrosion is a leading material degradation mode observed in many military systems. This report contains a description of a small project that was performed to allow some of the important electrochemical aspects of two distinct and potentially relevant degradation modes to be better understood: environmentally assisted cracking (EAC) of aluminum alloys and corrosion in moist salt. Two specific and respective tasks were completed: (A) the characterization of the effect of aluminum microstructural variability on its susceptibility to EAC, and (B) the development of experimental and analytical techniques that can be used to identify the factors and processes that influence the corrosivity of moist salt mixtures. The resultant information constitutes part of the basis needed to ultimately predict component reliability and/or possibly to identify techniques that could be used to control corrosion in critical components. In Task A, a physical model and related understanding for the relevant degradation processes were formulated. The primary result from Task B included the identification and qualitative validation of a methodology for determining the corrosivity of salt mixtures. A detailed compilation of the results obtained from each of these two diverse tasks is presented separately in the body of this report.

  15. Encoding and processing biologically relevant temporal information in electrosensory systems.

    PubMed

    Fortune, E S; Rose, G J; Kawasaki, M

    2006-06-01

    Wave-type weakly electric fish are specialists in time-domain processing: behaviors in these animals are often tightly correlated with the temporal structure of electrosensory signals. Behavioral responses in these fish can be dependent on differences in the temporal structure of electrosensory signals alone. This feature has facilitated the study of temporal codes and processing in central nervous system circuits of these animals. The temporal encoding and mechanisms used to transform temporal codes in the brain have been identified and characterized in several species, including South American gymnotid species and in the African mormyrid genus Gymnarchus. These distantly related groups use similar strategies for neural computations of information on the order of microseconds, milliseconds, and seconds. Here, we describe a suite of mechanisms for behaviorally relevant computations of temporal information that have been elucidated in these systems. These results show the critical role that behavioral experiments continue to have in the study of the neural control of behavior and its evolution. PMID:16450118

  16. On some fundamentals of igneous petrology

    NASA Astrophysics Data System (ADS)

    Marsh, Bruce D.

    2013-09-01

    The age-old process of crystal fractionation leading to the diversity of the igneous rocks and Earth itself is an exceedingly well-understood chemical process in magmatism and physical chemistry. But the broader physical aspects of this and related processes have proven elusive on many fronts, especially in its relation to the spatial variations in rock composition, texture, and macroscopic features like layering. Magmatic systems, be they volcanic, dikes, sills, or plutons, are generally analyzed with a problem at hand and an end result in mind. The processes invoked to solve these problems, which are most often purely chemical, are often unique to each problem with few if any general principles emerging that are central to understanding the wider perspective of magmatic processes and problems. An attempt is made at the outset to provide a list of inviolate Magmatic First Principles that are relevant to analyzing most magmatic problems. These involve: initial conditions; critical crystallinity; solidification fronts; transport and emplacement fluxes; phenocrysts, xenocrysts, primocrysts; crystal size; layering and crystal sorting; thermal convection; magmatic processes are physical. Along with these principles, two reference magmatic systems are suggested where the initial conditions and outcome are unequivocal: the Sudbury impact melt sheet and the Hawaiian lava lakes. Sudbury formed in ~5 min by superheated magma crystallized to a near uniform sequence, while the tiny lava lakes, formed of crystal-laden slurries, form a highly differentiated layered sequence. The major difference is in the initial conditions of formation, especially the nature of the input materials. The challenge is to construct and analyze magmatic systems (i.e., magma chambers, sills, dikes, and lavas) using these reference end members and the suggested principles. The Hawaiian 500,000 year volcanic record exhibits what can be expected as input materials, namely a highly varied output of

  17. Trace elements in magnetite from massive iron oxide-apatite deposits indicate a combined formation by igneous and magmatic-hydrothermal processes

    NASA Astrophysics Data System (ADS)

    Knipping, Jaayke L.; Bilenker, Laura D.; Simon, Adam C.; Reich, Martin; Barra, Fernando; Deditius, Artur P.; Wälle, Markus; Heinrich, Christoph A.; Holtz, François; Munizaga, Rodrigo

    2015-12-01

    Iron oxide-apatite (IOA) deposits are an important source of iron and other elements (e.g., REE, P, U, Ag and Co) vital to modern society. However, their formation, including the namesake Kiruna-type IOA deposit (Sweden), remains controversial. Working hypotheses include a purely magmatic origin involving separation of an Fe-, P-rich, volatile-rich oxide melt from a Si-rich silicate melt, and precipitation of magnetite from an aqueous ore fluid, which is either of magmatic-hydrothermal or non-magmatic surface or metamorphic origin. In this study, we focus on the geochemistry of magnetite from the Cretaceous Kiruna-type Los Colorados IOA deposit (∼350 Mt Fe) located in the northern Chilean Iron Belt. Los Colorados has experienced minimal hydrothermal alteration that commonly obscures primary features in IOA deposits. Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) transects and electron probe micro-analyzer (EPMA) wavelength-dispersive X-ray (WDX) spectrometry mapping demonstrate distinct chemical zoning in magnetite grains, wherein cores are enriched in Ti, Al, Mn and Mg. The concentrations of these trace elements in magnetite cores are consistent with igneous magnetite crystallized from a silicate melt, whereas magnetite rims show a pronounced depletion in these elements, consistent with magnetite grown from an Fe-rich magmatic-hydrothermal aqueous fluid. Further, magnetite grains contain polycrystalline inclusions that re-homogenize at magmatic temperatures (>850 °C). Smaller inclusions (<5 μm) contain halite crystals indicating a saline environment during magnetite growth. The combination of these observations are consistent with a formation model for IOA deposits in northern Chile that involves crystallization of magnetite microlites from a silicate melt, nucleation of aqueous fluid bubbles on magnetite surfaces, and formation and ascent of buoyant fluid bubble-magnetite aggregates. Decompression of the fluid-magnetite aggregate

  18. Kinetics of Elementary Processes Relevant to Incipient Soot Formation

    SciTech Connect

    Lin, M C; Heaven, M C

    2008-04-30

    Soot formation and abatement processes are some of the most important and challenging problems in hydrocarbon combustion. The key reactions involved in the formation of polycyclic aromatic hydrocarbons (PAH's), the precursors to soot, remain elusive. Small aromatic species such as C5H5, C6H6 and their derivatives are believed to play a pivotal role in incipient soot formation. The goal of this project is to establish a kinetic database for elementary reactions relevant to soot formation in its incipient stages. In the past year, we have completed by CRDS the kinetics for the formation and decomposition of C6H5C2H2O2 in the C6H5C2H2 +O2 reaction and the formation of C10H7O2 in the C10H7 + O2 reaction by directly monitoring C6H5C2H2O2 and C10H7O2 radicals in the visible region; their mechanisms have been elucidated computationally by quantum-chemical calculations. The O + C2H5OH reaction has been studied experimentally and computationally and the OH + HNCN reaction has been investigated by ab initio molecular orbital calculation. In addition, a new pulsed slit molecular beam system has been constructed and tested for spectroscopic studies of aromatic radicals and their derivatives by the cavity ringdown technique (CRDS).

  19. Petrology of the igneous rocks

    NASA Technical Reports Server (NTRS)

    Mccallum, I. S.

    1987-01-01

    Papers published during the 1983-1986 period on the petrology and geochemistry of igneous rocks are discussed, with emphasis on tectonic environment. Consideration is given to oceanic rocks, subdivided into divergent margin suites (mid-ocean ridge basalts, ridge-related seamounts, and back-arc basin basalts) and intraplate suites (oceanic island basalts and nonridge seamounts), and to igneous rocks formed at convergent margins (island arc and continental arc suites), subdivided into volcanic associations and plutonic associations. Other rock groups discussed include continental flood basalts, layered mafic intrusions, continental alkalic associations, komatiites, ophiolites, ash-flow tuffs, anorthosites, and mantle xenoliths.

  20. Surface chemistry relevant to material processing for semiconductor devices

    NASA Astrophysics Data System (ADS)

    Okada, Lynne Aiko

    Metal-oxide-semiconductor (MOS) structures are the core of many modern integrated circuit (IC) devices. Each material utilized in the different regions of the device has its own unique chemistry. Silicon is the base semiconductor material used in the majority of these devices. With IC device complexity increasing and device dimensions decreasing, understanding material interactions and processing becomes increasingly critical. Hsb2 desorption is the rate-limiting step in silicon growth using silane under low temperature conditions. Activation energies for Hsb2 desorption measured during Si chemical vapor deposition (CVD) versus single-crystal studies are found to be significantly lower. It has been proposed that defect sites on the silicon surface could explain the observed differences. Isothermal Hsb2 desorption studies using laser induced thermal desorption (LITD) techniques have addressed this issue. The growth of low temperature oxides is another relevant issue for fabrication of IC devices. Recent studies using 1,4-disilabutane (DSB) (SiHsb3CHsb2CHsb2SiHsb3) at 100sp°C in ambient Osb2 displayed the successful low temperature growth of silicon dioxide (SiOsb2). However, these studies provided no information about the deposition mechanism. We performed LITD and Fourier transform infrared (FTIR) studies on single-crystal and porous silicon surfaces to examine the adsorption, decomposition, and desorption processes to determine the deposition mechanism. Titanium nitride (TiN) diffusion barriers are necessary in modern metallization structures. Controlled deposition using titanium tetrachloride (TiClsb4) and ammonia (NHsb3) has been demonstrated using atomic layered processing (ALP) techniques. We intended to study the sequential deposition method by monitoring the surface intermediates using LITD techniques. However, formation of a Cl impurity source, ammonium chloride (NHsb4sp+Clsp-), was observed, thereby, limiting our ability for effective studies. Tetrakis

  1. Winter Ice and Snow as Models of Igneous Rock Formation.

    ERIC Educational Resources Information Center

    Romey, William D.

    1983-01-01

    Examines some features of ice and snow that offer teachers and researchers help in understanding many aspects of igneous processes and configurations. Careful observation of such processes as melting, decay, evolution, and snow accumulation provide important clues to understanding processes by which many kinds of rocks form. (Author/JN)

  2. An ERP indicator of processing relevant gestalts in masked priming.

    PubMed

    Verleger, Rolf; Görgen, Stefani; Jaśkowski, Piotr

    2005-11-01

    Briefly presented arrows, made indistinguishable by masks that contain arrows, inversely prime responses to following visible arrows. This inverse effect might reflect general regularities of masked priming or be either due to the task-relevant elements of the mask or to special features of arrows. Here we report a slow negative EEG potential recorded from the scalp above the visual cortex, which is evoked by masks that contain arrows. Even being evoked when arrows masks were presented in isolation, this "Nd-mask" appeared to be an obligatory response. Yet Nd-mask was enhanced when primes and targets were arrows and was reduced in the other cases, and even reversed its polarity with appropriate control stimuli. These findings provide support both for the special status of arrows and for the notion of mask relevance. Nd-mask might be one instance of negative EEG potentials evoked by stimuli with familiar gestalts. PMID:16364063

  3. Cognitive Processes in Spelling and Their Relevance to Spelling Reform.

    ERIC Educational Resources Information Center

    Frith, Uta

    Cognitive psychology has provided an information processing model that distinguishes between input processes such as listening to speech or reading and output processes such as speaking or writing. It is useful for spelling reformers to consider reading (input) and writing (output) processes separately, because the demands of the reader and of the…

  4. Igneous Graphite in Enstatite Chondrites

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.

    1997-01-01

    Igneous graphite. a rare constituent in terrestrial mafic and ultramafic rocks. occurs in three EH and one EL enstatite chondrite impact-melt breccias as 2-150 Ilm long euhedrallaths. some with pyramidal terminations. In contrast. graphite in most enstatite chondrites exsolved from metallic Fe-Ni as polygonal. rounded or irregular aggregates. Literature data for five EH chondrites on C combusting at high temperatures show that Abee contains the most homogeneous C isotopes (i.e. delta(sup 13)C = -8.1+/-2.1%); in addition. Abee's mean delta(sup l3)C value is the same as the average high-temperature C value for the set of five EH chondrites. This suggests that Abee scavenged C from a plurality of sources on its parent body and homogenized the C during a large-scale melting event. Whereas igneous graphite in terrestrial rocks typically forms at relatively high pressure and only moderately low oxygen fugacity (e.g., approx. 5 kbar. logfO2, approx. -10 at 1200 C ). igneous graphite in asteroidal meteorites formed at much lower pressures and oxygen fugacities.

  5. Spirit Discovers New Class of Igneous Rocks

    NASA Technical Reports Server (NTRS)

    2006-01-01

    During the past two-and-a-half years of traversing the central part of Gusev Crater, NASA's Mars Exploration Rover Spirit has analyzed the brushed and ground-into surfaces of multiple rocks using the alpha particle X-ray spectrometer, which measures the abundance of major chemical elements. In the process, Spirit has documented the first example of a particular kind of volcanic region on Mars known as an alkaline igneous province. The word alkaline refers to the abundance of sodium and potassium, two major rock-forming elements from the alkali metals on the left-hand side of the periodic table.

    All of the relatively unaltered rocks -- those least changed by wind, water, freezing, or other weathering agents -- examined by Spirit have been igneous, meaning that they crystallized from molten magmas. One way geologists classify igneous rocks is by looking at the amount of potassium and sodium relative to the amount of silica, the most abundant rock-forming mineral on Earth. In the case of volcanic rocks, the amount of silica present gives scientists clues to the kind of volcanism that occurred, while the amounts of potassium and sodium provide clues about the history of the rock. Rocks with more silica tend to erupt explosively. Higher contents of potassium and sodium, as seen in alkaline rocks like those at Gusev, may indicate partial melting of magma at higher pressure, that is, deeper in the Martian mantle. The abundance of potassium and sodium determines the kinds of minerals that make up igneous rocks. If igneous rocks have enough silica, potassium and sodium always bond with the silica to form certain minerals.

    The Gusev rocks define a new chemical category not previously seen on Mars, as shown in this diagram plotting alkalis versus silica, compiled by University of Tennessee geologist Harry McSween. The abbreviations 'Na2O' and 'K2O' refer to oxides of sodium and potassium. The abbreviation 'SiO2' refers to silica. The abbreviation 'wt

  6. Alcohol sensory processing and its relevance for ingestion.

    PubMed

    Brasser, Susan M; Castro, Norma; Feretic, Brian

    2015-09-01

    Alcohol possesses complex sensory attributes that are first detected by the body via sensory receptors and afferent fibers that promptly transmit signals to brain areas involved in mediating ingestive motivation, reinforcement, and addictive behavior. Given that the chemosensory cues accompanying alcohol consumption are among the most intimate, consistent, and immediate predictors of alcohol's postabsorptive effects, with experience these stimuli also gain powerful associative incentive value to elicit craving and related physiologic changes, maintenance of ongoing alcohol use, and reinstatement of drug seeking after periods of abstinence. Despite the above, preclinical research has traditionally dichotomized alcohol's taste and postingestive influences as independent regulators of motivation to drink. The present review summarizes current evidence regarding alcohol's ability to directly activate peripheral and central oral chemosensory circuits, relevance for intake of the drug, and provides a framework for moving beyond a dissociation between the sensory and postabsorptive effects of alcohol to understand their neurobiological integration and significance for alcohol addiction. PMID:25304192

  7. Temperament, Anxiety, and the Processing of Threat-Relevant Stimuli

    ERIC Educational Resources Information Center

    Lonigan, Christopher J.; Vasey, Michael W.; Phillips, Beth M.; Hazen, Rebecca A.

    2004-01-01

    This article discusses converging evidence from developmental, clinical, and cognitive psychology suggesting that there is significant overlap between research findings on affect, temperament, and attentional processes associated with pathological anxiety. We offer a proposal for the integration of these 3 areas aimed at developing a more clear…

  8. On the relevance of glycolysis process on brain gliomas.

    PubMed

    Kounelakis, M G; Zervakis, M E; Giakos, G C; Postma, G J; Buydens, L M C; Kotsiakis, X

    2013-01-01

    The proposed analysis considers aspects of both statistical and biological validation of the glycolysis effect on brain gliomas, at both genomic and metabolic level. In particular, two independent datasets are analyzed in parallel, one engaging genomic (Microarray Expression) data and the other metabolomic (Magnetic Resonance Spectroscopy Imaging) data. The aim of this study is twofold. First to show that, apart from the already studied genes (markers), other genes such as those involved in the human cell glycolysis significantly contribute in gliomas discrimination. Second, to demonstrate how the glycolysis process can open new ways towards the design of patient-specific therapeutic protocols. The results of our analysis demonstrate that the combination of genes participating in the glycolytic process (ALDOA, ALDOC, ENO2, GAPDH, HK2, LDHA, LDHB, MDH1, PDHB, PFKM, PGI, PGK1, PGM1 and PKLR) with the already known tumor suppressors (PTEN, Rb, TP53), oncogenes (CDK4, EGFR, PDGF) and HIF-1, enhance the discrimination of low versus high-grade gliomas providing high prediction ability in a cross-validated framework. Following these results and supported by the biological effect of glycolytic genes on cancer cells, we address the study of glycolysis for the development of new treatment protocols. PMID:22614725

  9. Microbial Metagenomics Reveals Climate-Relevant Subsurface Biogeochemical Processes.

    PubMed

    Long, Philip E; Williams, Kenneth H; Hubbard, Susan S; Banfield, Jillian F

    2016-08-01

    Microorganisms play key roles in terrestrial system processes, including the turnover of natural organic carbon, such as leaf litter and woody debris that accumulate in soils and subsurface sediments. What has emerged from a series of recent DNA sequencing-based studies is recognition of the enormous variety of little known and previously unknown microorganisms that mediate recycling of these vast stores of buried carbon in subsoil compartments of the terrestrial system. More importantly, the genome resolution achieved in these studies has enabled association of specific members of these microbial communities with carbon compound transformations and other linked biogeochemical processes-such as the nitrogen cycle-that can impact the quality of groundwater, surface water, and atmospheric trace gas concentrations. The emerging view also emphasizes the importance of organism interactions through exchange of metabolic byproducts (e.g., within the carbon, nitrogen, and sulfur cycles) and via symbioses since many novel organisms exhibit restricted metabolic capabilities and an associated extremely small cell size. New, genome-resolved information reshapes our view of subsurface microbial communities and provides critical new inputs for advanced reactive transport models. These inputs are needed for accurate prediction of feedbacks in watershed biogeochemical functioning and their influence on the climate via the fluxes of greenhouse gases, CO2, CH4, and N2O. PMID:27156744

  10. Electron-Nitrogen Collision Processes Relevant to Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Johnson, Paul

    2011-06-01

    Electron-N2 collisions play an important role in the nitrogen-rich upper atmospheres of Titan, Triton, and Earth. Modeling these processes requires accurate laboratory data. Despite the recognized importance of such data, there remained an unsatisfactory degree of consensus among much of the available laboratory collision cross section data. To address this situation, our group has devoted considerable effort over the past decade to improve the status of low energy electron collision data. In doing so, we have measured direct excitation cross sections for at least 17 electronic states of neutral N2 and a variety of key UV emission cross sections. Here we review the result of this effort, highlighting how the picture of electron collision processes has evolved, where consensus has been reached and where discrepancies still exist. New electron energy-loss measurements will be presented for excitation of the valence states, with finely spaced (<1eV) impact energy increments in the threshold-to-peak region where excitation is not in proportion to the Franck-Condon factors. These data are novel in that they include measurements at fixed electron scattering angles, differential in impact energy over a range of scattering angle. Also, new near-threshold integral cross sections are provided and compared to existing data.

  11. Pristine Igneous Rocks and the Early Differentiation of Planetary Materials

    NASA Technical Reports Server (NTRS)

    Warren, Paul H.

    2005-01-01

    Our studies are highly interdisciplinary, but are focused on the processes and products of early planetary and asteroidal differentiation, especially the genesis of the ancient lunar crust. The compositional diversity that we explore is the residue of process diversity, which has strong relevance for comparative planetology. Most of the accessible lunar crust consists of materials hybridized by impact-mixing. Our lunar research concentrates on the rare pristine (unmixed) samples that reflect the original genetic diversity of the early crust. Among HED basalts (eucrites and clasts in howardites), we distinguish as pristine the small minority that escaped the pervasive thermal metamorphism of the parent asteroid's crust. We have found a correlation between metamorphically pristine HED basalts and the similarly small minority of compositionally evolved "Stannern trend" samples, which are enriched in incompatible elements and titanium compared to main group eucrites, and yet have relatively high mg ratios. Other topics under investigation included: lunar and SNC (martian?) meteorites; igneous meteorites in general; impact breccias, especially metal-rich Apollo samples and polymict eucrites; siderophile compositions of the lunar and martian mantles; and planetary bulk compositions and origins.

  12. Inferring Relevance of Matrix and Preferential Flow Processes Flow Multi-Year Well Concentration Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Preferential and matrix flow are the two dominate processes influencing chemical transport to groundwater. Unfortunately the relevance of these processes is difficult to quantify without chemical flux data. Seventy-one observations times from 31, 3-m wells were evaluated to determine relevance of p...

  13. Igneous Activity at Yucca Mountain: Technical Basis for Decision Making

    NASA Astrophysics Data System (ADS)

    Hinze, W.; Marsh, B.; Weiner, R.; Coleman, N.

    2007-12-01

    Eighty thousand years ago a small-volume basaltic volcano erupted 20 km south of the Department of Energy's (DOE) proposed high-level radioactive waste repository at Yucca Mountain, Nevada. Lathrop Wells is one of the infrequent basaltic volcanoes that have occurred near Yucca Mountain during the past 10 million years. The Advisory Committee on Nuclear Waste and Materials (ACNW&M) has prepared a summary and analysis of the technical views on the nature, likelihood and potential consequences of future igneous activity at the proposed repository. The technical views have been abstracted from public literature and agency reports. Alternate views reflect uncertainties of the igneous processes that have occurred in the region and those that are likely to occur, as well as the interaction of these processes with the proposed repository. There is general agreement that either extrusive or intrusive igneous activity may occur. The extrusive scenario is likely to cause a larger risk and the effect is greatest within the first thousand years. The nature of igneous activity that could occur will probably be similar in composition, structure, and style to the Lathrop Wells volcano. Certain styles of volcanism, like explosive phreatic eruptions (maar volcanism) are not expected because conditions necessary for these do not exist at Yucca Mountain. The volcanic record, particularly during the past 5 million years, suggests a variety of models for evaluating the probability of future igneous activity. The anticipated range of probability of an igneous event intersecting the proposed repository is low, between 1E-9 and 1E-7/yr. An ongoing DOE expert elicitation incorporating the latest geophysical and drilling data will provide an up-to-date, credible estimate of the probability of volcanic intersection. An understanding of the processes involved in interaction between magma and drifts, waste packages, and waste is evolving and providing new insights. As a result, there is limited

  14. Interactive Effects of Working Memory Self-Regulatory Ability and Relevance Instructions on Text Processing

    ERIC Educational Resources Information Center

    Hamilton, Nancy Jo

    2012-01-01

    Reading is a process that requires the enactment of many cognitive processes. Each of these processes uses a certain amount of working memory resources, which are severely constrained by biology. More efficiency in the function of working memory may mediate the biological limits of same. Reading relevancy instructions may be one such method to…

  15. Self-glazing ceramic tiles based on acidic igneous glasses

    SciTech Connect

    Merkin, A.P.; Nanazashvili, V.I.

    1988-07-01

    A technology was derived to produce self-glazing ceramic tiles based on single-component systems of acidic igneous (volcanic) glasses. A weakly alkaline solution of NaOH or KOH was used as the sealing water to activate the sintering process. Tests conducted on the self-glazing ceramic tiles showed that their water absorption amounts to 2.5-8%, linear shrinkage is 3.2-7%, and frost resistance amounts to 35-70 cycles. The application of acidic igneous glasses as the main raw material for the production of ceramic facing tiles made it possible to widen the raw material base and simplify the technology for fabricating ceramic facing tiles at lower cost. The use of waste products when processing perlite-bearing rocks, when carrying out mining and cutting of tuffs, slags, and tuff breccia for recovering cut materials was recommended.

  16. Igneous Consequence Modeling for the TSPA-SR

    SciTech Connect

    John McCord

    2001-10-29

    code is not run within this AMR and any sensitivity runs will be performed within the TSPA-SR. This change has no impact on the technical output from this AMR. The objectives of the work are to: (1) Develop TSPA-SR conceptual models for volcanic eruptive and igneous intrusion groundwater transport releases from igneous activity consistent with the available conceptual models and data; (2) Document support from conceptual models and data; (3) Deliver conceptual model parameter inputs to the TSPA-SR Model; (4) Provide appropriate documentation for conceptual models, data, and parameters to relevant project databases; and (5) Recommend an appropriate mathematical model for the volcanic eruption release scenario and provide appropriate parameter values for this model which will be run within the TSPA-SR Model.

  17. On the Basic Principles of Igneous Petrology

    NASA Astrophysics Data System (ADS)

    Marsh, B. D.

    2014-12-01

    How and why Differentiation occurs has dominated Igneous Petrology since its beginning (~1880) even though many of the problems associated with it have been thoroughly solved. Rediscovery of the proverbial wheel with new techniques impedes progress. As soon as thin section petrography was combined with rock and mineral chemistry, rock diversity, compositional suites, and petrographic provinces all became obvious. The masterful 1902 CIPW norm in a real sense solved the chemical mystery of differentiation: rocks are related by the addition and subtraction of minerals in the anciently appreciated process of fractional crystallization. Yet few believed this, even after phase equilibria arrived. Assimilation, gas transfer, magma mixing, Soret diffusion, immiscibility, and other processes had strong adherents, even though by 1897 Becker conclusively showed the ineffectiveness of molecular diffusion in large-scale processes. The enormity of heat to molecular diffusion (today's Lewis no.) should have been convincing; but few paid attention. Bowen did, and he refined and restated the result; few still paid attention. And in spite of his truly masterful command of experiment and field relations in promoting fractional crystallization, Fenner and others fought him with odd arguments. The beauty of phase equilibria eventually dominated at the expense of knowing the physical side of differentiation. Bowen himself saw and struggled with the connection between physical and chemical processes. Progress has come from new concepts in heat transfer, kinetics, and slurry dynamics. The key approach is understanding the dynamic competition between spatial rates of solidification and all other processes. The lesson is clear: Scholarship and combined field, laboratory and technical expertise are critical to understanding magmatic processes. Magma is a limitlessly enchanting and challenging material wherein physical processes buttressed by chemistry govern.

  18. Crystallization trends of precursor pyroxene in ordinary chondrites: Implications for igneous origin of precursor

    NASA Technical Reports Server (NTRS)

    Fujita, T.; Kitamura, M.

    1994-01-01

    Various observations suggest that the precursor of the fine fragments and the relict pyroxene was formed by an igneous process in a grandparent body of the chondrite. Furthermore, the fact that the precursors appear as fragments in the matrix as well as relicts in the chondrule suggests a shock origin for the chondrite by collision of two or more bodies, which had already to some extent undergone igneous differentiation.

  19. Martian Igneous Geochemistry: The Nature of the Martian Mantle

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Elkins-Tanton, L. T.; Peng, Z. X.; Herrin, J. S.

    2012-01-01

    Mafic igneous rocks probe the interiors of their parent objects, reflecting the compositions and mineralogies of their source regions, and the magmatic processes that engendered them. Incompatible trace element contents of mafic igneous rocks are widely used to constrain the petrologic evolution of planets. We focus on incompatible element ratios of martian meteorites to constrain the petrologic evolution of Mars in the context of magma ocean/cumulate overturn models [1]. Most martian meteorites contain some cumulus grains, but regardless, their incompatible element ratios are close to those of their parent magmas. Martian meteorites form two main petrologic/ age groupings; a 1.3 Ga group composed of clinopyroxenites (nakhlites) and dunites (chassignites), and a <1 Ga group composed of basalts and lherzolites (shergottites).

  20. Measurement of proton capture cross sections relevant to rp process with Coulomb dissociation

    SciTech Connect

    Togano, Y.

    2010-08-12

    We have studied proton capture reactions on unstable proton-rich nuclei relevant to rapid proton-capture (rp) process using a Coulomb dissociation method. Using this method, three stellar reactions, {sup 22}Mg(p, {gamma}){sup 23}Al, {sup 26}Si(p, {gamma}){sup 27}P, and {sup 30}S(p, {gamma}){sup 31}Cl were studied at RIKEN Nishina Center. The radiative widths of the first excited state in {sup 23}Al and {sup 27}P, which are relevant to the stellar reactions, were obtained. We discuss the details of the Coulomb dissociation the astrophysical implications obtained from our studies.

  1. Organic Protomolecule Assembly in Igneous Minerals

    NASA Technical Reports Server (NTRS)

    Freund, Friedemann; Staple, Aaron; Scoville, John

    2001-01-01

    C-H stretching bands in the infrared spectrum of single crystals of nominally high purity, laboratory-grown MgO and of natural upper mantle olivine provide an "organic" signature that closely resembles the symmetrical and asymmetrical C-H stretching modes of aliphatic -CH2- units. The C-H stretching bands indicate that H20 and CO2, dissolved in the matrix of these minerals, converted to form H2 and chemically reduced C, which in turn formed C-H entities, probably through segregation into defects such as dislocations. Heating causes the C-H bonds to pyrolyze and the C-H stretching bands to disappear, but annealing at 70 C causes them to reappear within a few days or weeks. Modeling dislocations in MgO suggests that the segregation of C can lead to Cx chains, x less than or equal to 4, with the terminal C atoms anchored to the MgO matrix by bonding to two U. Allowing H2 to react with such Cx chains leads to [O2C(CH2)2CO2] or similar precipitates. It is suggested that such Cx-Hy-Oz entities represent protomolecules from which derive the short-chain carboxylic and dicarboxylic and of the medium-chain fatty acids that have been solvent-extracted from crushed MgO and olivine single crystals, respectively. Thus it appears that the hard, dense matrix of igneous minerals represents a medium in which protomolecular units can be assembled. During weathering of rocks the protomolecular units turn into complex organic molecules. These processes may have provided stereochemically constrained organics to the early Earth that were crucial to the emergence of Life.

  2. Organic protomolecule assembly in igneous minerals

    PubMed Central

    Freund, Friedemann; Staple, Aaron; Scoville, John

    2001-01-01

    C—H stretching bands, νCH, in the infrared spectrum of single crystals of nominally high purity, of laboratory-grown MgO, and of natural upper mantle olivine, provide an “organic” signature that closely resembles the symmetrical and asymmetrical C—H stretching modes of aliphatic —CH2 units. The νCH bands indicate that H2O and CO2, dissolved in the matrix of these minerals, converted to form H2 and chemically reduced C, which in turn formed C—H entities, probably through segregation into defects such as dislocations. Heating causes the C—H bonds to pyrolyze and the νCH bands to disappear, but annealing at 70°C causes them to reappear within a few days or weeks. Modeling dislocations in MgO suggests that the segregation of C can lead to Cx chains, x = 4, with the terminal C atoms anchored to the MgO matrix by bonding to two O−. Allowing H2 to react with such Cx chains leads to [O2C(CH2)2CO2] or similar precipitates. It is suggested that such Cx—Hy—Oz entities represent protomolecules from which derive the short-chain carboxylic and dicarboxylic and the medium-chain fatty acids that have been solvent-extracted from crushed MgO and olivine single crystals, respectively. Thus, it appears that the hard, dense matrix of igneous minerals represents a medium in which protomolecular units can be assembled. During weathering of rocks, the protomolecular units turn into complex organic molecules. These processes may have provided stereochemically constrained organics to the early Earth that were crucial to the emergence of life. PMID:11226206

  3. Synthesis of Co/Co3O4 nanocomposite particles relevant to magnetic field processing.

    PubMed

    Srivastava, A K; Madhavi, S; Menon, M; Ramanujan, R V

    2010-10-01

    Co/Co3O4 nanocomposite particles of various morphologies were synthesized by the reverse micelle technique. Equiaxed, rod and faceted crystals with rectangular, pentagonal and hexagonal cross sections were observed. Annealing resulted in the formation of a composite of cobalt oxide (Co3O4) and fcc cobalt (Co). Removal of boron residues from the final product was established by surface characterization. Magnetic moment of these nanocomposite particles is relevant to magnetic field processing. PMID:21137765

  4. Sudbury Igneous Complex: Impact melt or igneous rock? Implications for lunar magmatism

    NASA Technical Reports Server (NTRS)

    Norman, Marc D.

    1992-01-01

    The recent suggestion that the Sudbury Igneous Complex (SIC) is a fractionated impact melt may have profound implications for understanding the lunar crust and the magmatic history of the Moon. A cornerstone of much current thought on the Moon is that the development of the lunar crust can be traced through the lineage of 'pristine' igneous rocks. However, if rocks closely resembling those from layered igneous intrusions can be produced by differentiation of a large impact melt sheet, then much of what is thought to be known about the Moon may be called into question. This paper presents a brief evaluation of the SIC as a differentiated impact melt vs. endogenous igneous magma and possible implications for the magmatic history of the lunar crust.

  5. The relevance of rhythmical alternation in language processing: an ERP study on English compounds.

    PubMed

    Henrich, Karen; Alter, Kai; Wiese, Richard; Domahs, Ulrike

    2014-09-01

    This study investigates the influence of rhythmic expectancies on language processing. It is assumed that language rhythm involves an alternation of strong and weak beats within a linguistic domain. Hence, in some contexts rhythmically induced stress shifts occur in order to comply with the Rhythm Rule. In English, this rule operates to prevent clashes of stressed adjacent syllables or lapses of adjacent unstressed syllables. While previous studies investigated effects on speech production and perception, this study focuses on brain responses to structures either obeying or deviating from this rule. Event-related potentials show that rhythmic regularity is relevant for language processing: rhythmic deviations evoked different ERP components reflecting the deviance from rhythmic expectancies. An N400 effect found for shifted items reflects higher costs in lexical processing due to stress deviation. The overall results disentangle lexical and rhythmical influences on language processing and complement the findings of previous studies on rhythmical processing. PMID:25113242

  6. Examining the freezing process of an intermediate bulk containing an industrially relevant protein

    PubMed Central

    Reinsch, Holger; Spadiut, Oliver; Heidingsfelder, Johannes; Herwig, Christoph

    2015-01-01

    Numerous biopharmaceuticals are produced in recombinant microorganisms in the controlled environment of a bioreactor, a process known as Upstream Process. To minimize product loss due to physico-chemical and enzymatic degradation, the Upstream Process should be directly followed by product purification, known as Downstream Process. However, the Downstream Process can be technologically complex and time-consuming which is why Upstream and Downstream Process usually have to be decoupled temporally and spatially. Consequently, the product obtained after the Upstream Process, known as intermediate bulk, has to be stored. In those circumstances, a freezing procedure is often performed to prevent product loss. However, the freezing process itself is inseparably linked to physico-chemical changes of the intermediate bulk which may in turn damage the product. The present study analysed the behaviour of a Tris-buffered intermediate bulk containing a biopharmaceutically relevant protein during a bottle freezing process. Major damaging mechanisms, like the spatiotemporal redistribution of ion concentrations and pH, and their influence on product stability were investigated. Summarizing, we show the complex events which happen in an intermediate bulk during freezing and explain the different causes for product loss. PMID:25765305

  7. Crystal mat-formation as an igneous layering-forming process: Textural and geochemical evidence from the 'lower layered' nepheline syenite sequence of the Ilímaussaq complex, South Greenland

    NASA Astrophysics Data System (ADS)

    Lindhuber, Matthias J.; Marks, Michael A. W.; Bons, Paul D.; Wenzel, Thomas; Markl, Gregor

    2015-05-01

    The lower layered nepheline syenite sequence (kakortokites) of the Mesoproterozoic alkaline to peralkaline Ilímaussaq complex, South Greenland shows spectacular rhythmic meter-scale igneous layering. The 29 exposed units have sharp contacts against each other and each of these units consists of three modally graded layers dominated by arfvedsonitic amphibole, eudialyte-group minerals, and alkali feldspar, respectively. This study uses field observations on changes in mineral orientation, recurrent mineral textures, compositional data from eudialyte-group minerals and amphibole, and settling rate calculations based on a modified Stokes' equation to explain the igneous layering of the kakortokites. We propose that the three major cumulus minerals (amphibole, eudialyte s.l., and alkali feldspar) were separated from each other by density contrasts, resulting in modally graded layers within each unit. The densest of these three minerals (amphibole) formed crystal mats within the cooling magma body. These crystal mats acted as barriers that inhibited large-scale vertical migration of melts and crystals with increasing effectiveness over time. The sub-volumes of magma captured in between the crystal mats evolved largely as geochemically independent sub-systems, as indicated by the observed trends in mineral composition.

  8. Beta-decay spectroscopy relevant to the r-process nucleosynthesis

    SciTech Connect

    Nishimura, Shunji; Collaboration: RIBF Decay Collaboration

    2012-11-12

    A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

  9. Potential Future Igneous Activity at Yucca Mountain, Nevada

    SciTech Connect

    M. Cline; F. Perry; G. Valentine; E. Smistad

    2005-05-26

    Location, timing, and volumes of post-Miocene volcanic activity, along with expert judgment, provide the basis for assessing the probability of future volcanism intersecting a proposed repository for nuclear waste at Yucca Mountain, Nevada. Analog studies of eruptive centers in the region that may represent the style and extent of possible future igneous activity at Yucca Mountain have aided in defining the consequence scenarios for intrusion into and eruption through a proposed repository. Modeling of magmatic processes related to magma/proposed repository interactions has been used to assess the potential consequences of a future igneous event through a proposed repository at Yucca Mountain. Results of work to date indicate future igneous activity in the Yucca Mountain region has a very low probability of intersecting the proposed repository. Probability of a future event intersecting a proposed repository at Yucca Mountain is approximately 1.7 x 10{sup -8} per year. Since completion of the Probabilistic Volcanic Hazard Assessment (PVHA) in 1996, anomalies representing potential buried volcanic centers have been identified from aeromagnetic surveys. A re-assessment of the hazard is currently underway to evaluate the probability of intersection in light of new information and to estimate the probability of one or more volcanic conduits located in the proposed repository along a dike that intersects the proposed repository. US Nuclear Regulatory Commission regulations for siting and licensing a proposed repository require that the consequences of a disruptive event (igneous event) with annual probability greater than 1 x 10{sup -8} be evaluated. Two consequence scenarios are considered: (1) igneous intrusion-poundwater transport case and (2) volcanic eruptive case. These scenarios equate to a dike or dike swarm intersecting repository drifts containing waste packages, formation of a conduit leading to a volcanic eruption through the repository that carries the

  10. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    SciTech Connect

    Cavallo, Dario; Portale, Giuseppe; Androsch, René

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  11. Gaussian process classification using automatic relevance determination for SAR target recognition

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangrong; Gou, Limin; Hou, Biao; Jiao, Licheng

    2010-10-01

    In this paper, a Synthetic Aperture Radar Automatic Target Recognition approach based on Gaussian process (GP) classification is proposed. It adopts kernel principal component analysis to extract sample features and implements target recognition by using GP classification with automatic relevance determination (ARD) function. Compared with k-Nearest Neighbor, Naïve Bayes classifier and Support Vector Machine, GP with ARD has the advantage of automatic model selection and hyper-parameter optimization. The experiments on UCI datasets and MSTAR database show that our algorithm is self-tuning and has better recognition accuracy as well.

  12. Experimental studies of reactions relevant for γ-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Scholz, P.; Endres, J.; Hennig, A.; Mayer, J.; Netterdon, L.; Sauerwein, A.; Zilges, A.

    2014-05-01

    We report on our recent experimental studies of reactions relevant for the γ process nucleosynthesis. Applying the activation method using the Cologne Clover Counting Setup total cross sections of the reactions 168Yb(α,γ), 168Yb(α,n), and 187Re(α,n) could be obtained. Furthermore, the reaction 89Y(p,γ) was investigated via the in-beam technique with HPGe detectors at the high-efficiency g-ray spectrometer HORUS in Cologne in order to determine partial and total cross sections.

  13. Measurements of proton radiative capture cross sections relevant to the astrophysical rp- and γ-processes

    NASA Astrophysics Data System (ADS)

    Chloupek, F. R.; Murphy, A. St J.; Boyd, R. N.; Cole, A. L.; Görres, J.; Guray, R. T.; Raimann, G.; Zach, J. J.; Rauscher, T.; Schwarzenberg, J. V.; Tischhauser, P.; Wiescher, M. C.

    1999-06-01

    Measurements have been made of the 96Zr(p,γ)97Nb, 112Sn(p,γ)113Sb, and 119Sn(p,γ)120Sb cross section excitation functions. Incident proton energies ranged from 2.8 MeV to 8.5 MeV. These reactions are relevant to several processes of stellar nucleosynthesis. The resulting astrophysical S-factors are compared to those from theoretical statistical model calculations using the SMOKER, and the more recent NON-SMOKER, codes to judge their applicability to these reactions.

  14. Modeling the evolution of Sm and Eu abundances during lunar igneous differentiation

    NASA Technical Reports Server (NTRS)

    Weill, D. F.; Mckay, G. A.; Kridelbaugh, S. J.; Grutzeck, M.

    1974-01-01

    The current work presents models for the evolution of europium and samarium abundances during lunar igneous processes. The effect of probable variations in lunar temperature and oxygen fugacity, mineral-liquid distribution coefficients, and the crystallization or melting progression are considered in the model calculations. Changes in the proportions of crystallizing phases strongly influence the evolution of trace element abundances during fractional crystallization, and models must include realistic estimates of the major phase equilibria during crystallization. The results are applied to evaluating the possibility of generating KREEP-rich materials by lunar igneous processes.

  15. Ocean anoxia and large igneous provinces

    NASA Astrophysics Data System (ADS)

    Ruhl, Micha; Bjerrum, Christian J.; Canfield, Donald E.; Korte, Christoph; Stemmerik, Lars; Frei, Robert

    2013-04-01

    Earth's history is marked by multiple events of ocean anoxia developing along continental margins and potentially into the open ocean realm. These events often coincide with the emplacement of large igneous provinces (LIPs) on continents, major perturbations of global geochemical cycles and marine (mass) extinction. The geographic and temporal extend and the intensity (ferruginous vs. euxinic) of anoxic conditions is often, however, poorly constraint. This complicates understanding of close coupling between Earth's physical, chemical and biological processes. We studied ocean redox change over two major mass extinction events in Earth history, the Permian-Triassic (at ~252 Ma) and Triassic-Jurassic (at ~201.3 Ma) mass extinctions. Both extinction events are marked by a major perturbation of the global exogenic carbon cycle (and associated major negative carbon isotope excursion (CIE)), likely initiated by carbon outgassing of the Siberian Traps and the Central Atlantic Magmatic Province (CAMP), respectively. We compare Permian-Triassic and Triassic-Jurassic ocean redox change along continental margins in different geographic regions (Permian-Triassic: Greenland, Svalbard, Iran; Triassic-Jurassic: UK, Austria) and discuss its role in marine mass extinction. We show strongly enhanced sedimentary redox-sensitive trace element concentrations (e.g. Mo) during both events. However, increased Permian-Triassic values are in all localities distinctly delayed relative to the associated negative CIE. Triassic-Jurassic values are only delayed in the oceanographically restricted western Germanic basin (UK) while increased Mo-values in the north-western Tethys Ocean (Austria) directly match the onset of the associated negative CIE. Speciation of iron [giving (Fe-HR/ Fe-T) and (Fe(Py)/ Fe-HR)] in the Triassic-Jurassic western Germanic basin (UK) however shows close coupling between the onset of the global carbon cycle perturbation and a shift to anoxic and even euxinic conditions

  16. Teaching Igneous and Metamorphic Petrology Through Guided Inquiry Projects

    NASA Astrophysics Data System (ADS)

    McMillan, N. J.

    2003-12-01

    Undergraduate Petrology at New Mexico State University (GEOL 399) has been taught using three, 5-6 week long projects in place of lectures, lab, and exams for the last six years. Reasons for changing from the traditional format include: 1) to move the focus from identification and memorization to petrologic thinking; 2) the need for undergraduate students to apply basic chemical, structural, and field concepts to igneous and metamorphic rocks; 3) student boredom in the traditional mode by the topic that has captivated my professional life, in spite of my best efforts to offer thrilling lectures, problems, and labs. The course has three guided inquiry projects: volcanic, plutonic, and pelitic dynamothermal. Two of the rock suites are investigated during field trips. Each project provides hand samples and thin sections; the igneous projects also include whole-rock major and trace element data. Students write a scientific paper that classifies and describes the rocks, describes the data (mineralogical and geochemical), and uses data to interpret parameters such as tectonic setting, igneous processes, relationship to phase diagrams, geologic history, metamorphic grade, metamorphic facies, and polymetamorphic history. Students use the text as a major resource for self-learning; mini-lectures on pertinent topics are presented when needed by the majority of students. Project scores include evaluation of small parts of the paper due each Friday and participation in peer review as well as the final report. I have found that petrology is much more fun, although more difficult, to teach using this method. It is challenging to be totally prepared for class because students are working at different speeds on different levels on different aspects of the project. Students enjoy the course, especially the opportunity to engage in scientific investigation and debate. A significant flaw in this course is that students see fewer rocks and have less experience in rock classification

  17. Dynamic Effects of Self-Relevance and Task on the Neural Processing of Emotional Words in Context

    PubMed Central

    Fields, Eric C.; Kuperberg, Gina R.

    2016-01-01

    We used event-related potentials (ERPs) to examine the interactions between task, emotion, and contextual self-relevance on processing words in social vignettes. Participants read scenarios that were in either third person (other-relevant) or second person (self-relevant) and we recorded ERPs to a neutral, pleasant, or unpleasant critical word. In a previously reported study (Fields and Kuperberg, 2012) with these stimuli, participants were tasked with producing a third sentence continuing the scenario. We observed a larger LPC to emotional words than neutral words in both the self-relevant and other-relevant scenarios, but this effect was smaller in the self-relevant scenarios because the LPC was larger on the neutral words (i.e., a larger LPC to self-relevant than other-relevant neutral words). In the present work, participants simply answered comprehension questions that did not refer to the emotional aspects of the scenario. Here we observed quite a different pattern of interaction between self-relevance and emotion: the LPC was larger to emotional vs. neutral words in the self-relevant scenarios only, and there was no effect of self-relevance on neutral words. Taken together, these findings suggest that the LPC reflects a dynamic interaction between specific task demands, the emotional properties of a stimulus, and contextual self-relevance. We conclude by discussing implications and future directions for a functional theory of the emotional LPC. PMID:26793138

  18. The role of igneous sills in shaping the Martian uplands

    NASA Technical Reports Server (NTRS)

    Wilhelms, D. E.; Baldwin, R. J.

    1989-01-01

    Relations among geologic units and landforms suggest that igneous sills lie beneath much of the intercrater and intracrater terrain of the Martian uplands. The igneous rocks crop out along the upland-lowland front and in crater floors and other depressions that are low enough to intersect the sill's intrusion horizons. It is suggested that heat from the cooling sills melted some of the ice contained in overlying fragmental deposits, creating valley networks by subsurface flow of the meltwater. Terrains with undulatory, smooth surfaces and softened traces of valleys were created by more direct contact with the sills. Widespread subsidence following emplacement of the sills deformed both them and the nonvolcanic deposits that overlie them, accounting for the many structures that continue from ridged plains into the hilly uplands. Crater counts show that the deposit that became valleyed, softened, and ridged probably began to form (and to acquire interstitial ice) during or shortly after the Middle Noachian Epoch, and continued to form as late as the Early Hesperian Epoch. The upper layers of this deposit, many of the visible valleys, and the ridged plains and postulated sills all have similar Early Hesperian ages. Continued formation of valleys is indicated by their incision of fresh-appearing crater ejecta. The dependence of valley formation on internal processes implies that Mars did not necessarily have a dense early atmosphere or warm climate.

  19. Laboratory studies of chemical and photochemical processes relevant to stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

    1994-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(sub x) and NO(sub x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO2 radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. In this annual report, we focus on our recent accomplishments in the quantitative spectroscopy of the HO2 radical. This report details the measurements of the broadening coefficients for the v(sub 2) vibrational band. Further measurements of the vapor pressures of nitric acid hydrates relevant to the polar stratospheric cloud formation indicate the importance of metastable crystalline phases of H2SO4, HNO3, and H2O. Large particles produced from these metastable phases may provide a removal mechanism for HNO3 in the polar stratosphere.

  20. Presentation and interpretation of chemical data for igneous rocks

    USGS Publications Warehouse

    Wright, T.L.

    1974-01-01

    Arguments are made in favor of using variation diagrams to plot analyses of igneous rocks and their derivatives and modeling differentiation processes by least-squares mixing procedures. These methods permit study of magmatic differentiation and related processes in terms of all of the chemical data available. Data are presented as they are reported by the chemist and specific processes may be modeled and either quantitatively described or rejected as inappropriate or too simple. Examples are given of the differing interpretations that can arise when data are plotted on an AEM ternary vs. the same data on a full set of MgO variation diagrams. Mixing procedures are illustrated with reference to basaltic lavas from the Columbia Plateau. ?? 1974 Springer-Verlag.

  1. Stimulus-response correspondence effect as a function of temporal overlap between relevant and irrelevant information processing.

    PubMed

    Wang, Dong-Yuan Debbie; Richard, F Dan; Ray, Brittany

    2016-01-01

    The stimulus-response correspondence (SRC) effect refers to advantages in performance when stimulus and response correspond in dimensions or features, even if the common features are irrelevant to the task. Previous research indicated that the SRC effect depends on the temporal course of stimulus information processing. The current study investigated how the temporal overlap between relevant and irrelevant stimulus processing influences the SRC effect. In this experiment, the irrelevant stimulus (a previously associated tone) preceded the relevant stimulus (a coloured rectangle). The irrelevant and relevant stimuli onset asynchrony was varied to manipulate the temporal overlap between the irrelevant and relevant stimuli processing. Results indicated that the SRC effect size varied as a quadratic function of the temporal overlap between the relevant stimulus and irrelevant stimulus. This finding extends previous experimental observations that the SRC effect size varies in an increasing or decreasing function with reaction time. The current study demonstrated a quadratic function between effect size and the temporal overlap. PMID:26555858

  2. Magmatic systems of large continental igneous province

    NASA Astrophysics Data System (ADS)

    Sharkov, Evgenii

    2014-05-01

    Large igneous provinces (LIPs) of the modern type are known from the middle Paleoproterozoic and have a great abundance in the Phanerozoic. The most researches considered their appearance with ascending of the mantle thermochemical superplumes which provided simultaneously eruption of the same type of lavas on the huge territories. Judging on presence among them different subprovinces, formation of concrete magmatic systems were linked with protuberances (secondary plumes) on the superplumes surfaces. We suggest that origin of such plumes was linked with local enrichment of upper part of the superplumes head beneath roofing by fluid components; it led to lowering of the plume material density and initiated ascending of the secondary plumes. As a result, their heads, where partial melting occurred, can reach the level of the upper crust as it follows from absence of lower-crustal rocks among xenoliths in basalts, although mantle xenoliths existed in them. Important feature of LIPs is presence of two major types of mafic lavas: (1) geochemical-enriched alkali Fe-Ti basalts and picrites, and (2) basalts of normal alkalinity (tholeiites) with different contents of TiO2. At that the first type of mafites are usually typical for lower parts of LIPs which initially developed as continental rifts, whereas the second type composed the upper part of the traps' cover. Magmatic systems of the LIPs are subdivided on three levels of different deep: (1) zones of magma generation, (2) areas of transitional magma chambers where large often layered intrusive bodies are formed, and (3) areas on surface where lava eruptions and subvolcanic intrusions occurred. All these levels are linked by feeder dykes. The least known element of the system is area of magma generation, and, especially, composition of melting substratum. Important information about it is contained in aforementioned mantle xenoliths in alkali basalts and basanites. They practically everywhere are represented by two

  3. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Villalta, Peter W.; Zahniser, Mark S.; Nelson, David D.; Kolb, Charles E.

    1997-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(x) and NO(x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. The second year's effort has focussed the design and construction of the proposed high pressure flow reactor on three separate areas: (1) the construction of the high pressure flow reactor; (2) characterization of the turbulent flow profile; and (3) demonstration of the instrument by measuring HO2 + NO2 and HO2 + NO reaction rate coefficients.

  4. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Zahniser, Mark S.; Nelson, David D.; Worsnop, Douglas R.; Kolb, Charles E.

    1996-01-01

    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HOx and NOx species in the temperature range 200 K to 240 K relevant to the lower stratosphere. Other areas of study have included infrared spectroscopic studies of the HO radical, measurements of OH radical reactions with alternative fluorocarbons, and determination of the vapor pressures of nitric acid hydrates under stratospheric conditions. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences.

  5. High Xylose Yields from Dilute Acid Pretreatment of Corn Stover Under Process-Relevant Conditions

    SciTech Connect

    Weiss, N. D.; Nagle, N. J.; Tucker, M. P.; Elander, R. T.

    2009-01-01

    Pretreatment experiments were carried out to demonstrate high xylose yields at high solids loadings in two different batch pretreatment reactors under process-relevant conditions. Corn stover was pretreated with dilute sulfuric acid using a 4-l Steam Digester and a 4-l stirred ZipperClave{reg_sign} reactor. Solids were loaded at 45% dry matter (wt/wt) after sulfuric acid catalyst impregnation using nominal particle sizes of either 6 or 18 mm. Pretreatment was carried out at temperatures between 180 and 200 C at residence times of either 90 or 105 s. Results demonstrate an ability to achieve high xylose yields (>80%) over a range of pretreatment conditions, with performance showing little dependence on particle size or pretreatment reactor type. The high xylose yields are attributed to effective catalyst impregnation and rapid rates of heat transfer during pretreatment.

  6. Uranium in NIMROC standard igneous rock samples

    NASA Technical Reports Server (NTRS)

    Rowe, M. W.; Herndon, J. M.

    1976-01-01

    Results are reported for analysis of the uranium in multiple samples of each of six igneous-rock standards (dunite, granite, lujavrite, norite, pyroxenite, and syenite) prepared as geochemical reference standards for elemental and isotopic compositions. Powdered rock samples were examined by measuring delayed neutron emission after irradiation with a flux of the order of 10 to the 13th power neutrons/sq cm per sec in a nuclear reactor. The measurements are shown to compare quite favorably with previous uranium determinations for other standard rock samples.

  7. Petrogenesis of Igneous-Textured Clasts in Martian Meteorite Northwest Africa 7034

    NASA Technical Reports Server (NTRS)

    Santos, A. R.; Agee, C. B.; Humayun, M.; McCubbin, F. M.; Shearer, C. K.

    2016-01-01

    The martian meteorite Northwest Africa 7034 (and pairings) is a breccia that samples a variety of materials from the martian crust. Several previous studies have identified multiple types of igneous-textured clasts within the breccia [1-3], and these clasts have the potential to provide insight into the igneous evolution of Mars. One challenge presented by studying these small rock fragments is the lack of field context for this breccia (i.e., where on Mars it formed), so we do not know how many sources these small rock fragments are derived from or the exact formation his-tory of these sources (i.e., are the sources mantle de-rived melt or melts contaminated by a meteorite impactor on Mars). Our goal in this study is to examine specific igneous-textured clast groups to determine if they are petrogenetically related (i.e., from the same igneous source) and determine more information about their formation history, then use them to derive new insights about the igneous history of Mars. We will focus on the basalt clasts, FTP clasts (named due to their high concentration of iron, titanium, and phosphorous), and mineral fragments described by [1] (Fig. 1). We will examine these materials for evidence of impactor contamination (as proposed for some materials by [2]) or mantle melt derivation. We will also test the petrogenetic models proposed in [1], which are igneous processes that could have occurred regardless of where the melt parental to the clasts was formed. These models include 1) derivation of the FTP clasts from a basalt clast melt through silicate liquid immiscibility (SLI), 2) derivation of the FTP clasts from a basalt clast melt through fractional crystallization, and 3) a lack of petrogenetic relationship between these clast groups. The relationship between the clast groups and the mineral fragments will also be explored.

  8. On the observation of climate-relevant processes in the UTLS

    NASA Astrophysics Data System (ADS)

    Riese, Martin; Ungermann, Jörn

    2014-05-01

    Changes and variability of UTLS composition are major drivers of surface climate change (e.g. Solomon et al., 2010). Even small changes of spatially highly variable concentrations of greenhouse gases such as water vapor (H2O) and ozone (O3), aerosols and cirrus clouds have significant effects on the atmospheric radiation balance. Improved prediction capabilities of chemistry-climate models (CCM) therefore rely on a realistic representation of physical and chemical processes affecting UTLS composition. This is problematic, because UTLS composition is governed by the complex interactions of various physical and chemical processes that operate at a wide range of temporal and spatial scales (local to global). Water vapor and ozone are particularly sensitive to atmospheric transport due to their steep spatial mixing ratio gradients in this region. Small-scale trace gas filaments in the UTLS represent an important example of structures that are not yet adequately characterized. The same applies to small-scale gravity-waves that are important for the dynamical coupling between different atmospheric layers. In the past, most progress in our understanding of the UTLS and small-scale processes in this region was made on the basis of detailed airborne in-situ observations. Satellite limb observations, e. g. by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard Envisat, provided the global view, however, at limited spatial resolution. For this reason, there is a gap of observations concerning small-scale trace gas structures and temperature fluctuations, with a vertical extent of less than 500 m and a horizontal extent of less than 100 km. The talk will give an overview on climate-relevant processes in the UTLS and important associated scientific questions. Limitations of current observation system are discussed as well as need for three-dimensional observation of trace gases, clouds and temperature structures with adequate spatial resolution.

  9. An analytical and numerical study of Galton-Watson branching processes relevant to population dynamics

    NASA Astrophysics Data System (ADS)

    Jang, Sa-Han

    Galton-Watson branching processes of relevance to human population dynamics are the subject of this thesis. We begin with an historical survey of the invention of the invention of this model in the middle of the 19th century, for the purpose of modelling the extinction of unusual surnames in France and Britain. We then review the principal developments and refinements of this model, and their applications to a wide variety of problems in biology and physics. Next, we discuss in detail the case where the probability generating function for a Galton-Watson branching process is a geometric series, which can be summed in closed form to yield a fractional linear generating function that can be iterated indefinitely in closed form. We then describe the matrix method of Keyfitz and Tyree, and use it to determine how large a matrix must be chosen to model accurately a Galton-Watson branching process for a very large number of generations, of the order of hundreds or even thousands. Finally, we show that any attempt to explain the recent evidence for the existence thousands of generations ago of a 'mitochondrial Eve' and a 'Y-chromosomal Adam' in terms of a the standard Galton-Watson branching process, or indeed any statistical model that assumes equality of probabilities of passing one's genes to one's descendents in later generations, is unlikely to be successful. We explain that such models take no account of the advantages that the descendents of the most successful individuals in earlier generations enjoy over their contemporaries, which must play a key role in human evolution.

  10. The Role of the Auditory Brainstem in Processing Musically Relevant Pitch

    PubMed Central

    Bidelman, Gavin M.

    2013-01-01

    Neuroimaging work has shed light on the cerebral architecture involved in processing the melodic and harmonic aspects of music. Here, recent evidence is reviewed illustrating that subcortical auditory structures contribute to the early formation and processing of musically relevant pitch. Electrophysiological recordings from the human brainstem and population responses from the auditory nerve reveal that nascent features of tonal music (e.g., consonance/dissonance, pitch salience, harmonic sonority) are evident at early, subcortical levels of the auditory pathway. The salience and harmonicity of brainstem activity is strongly correlated with listeners’ perceptual preferences and perceived consonance for the tonal relationships of music. Moreover, the hierarchical ordering of pitch intervals/chords described by the Western music practice and their perceptual consonance is well-predicted by the salience with which pitch combinations are encoded in subcortical auditory structures. While the neural correlates of consonance can be tuned and exaggerated with musical training, they persist even in the absence of musicianship or long-term enculturation. As such, it is posited that the structural foundations of musical pitch might result from innate processing performed by the central auditory system. A neurobiological predisposition for consonant, pleasant sounding pitch relationships may be one reason why these pitch combinations have been favored by composers and listeners for centuries. It is suggested that important perceptual dimensions of music emerge well before the auditory signal reaches cerebral cortex and prior to attentional engagement. While cortical mechanisms are no doubt critical to the perception, production, and enjoyment of music, the contribution of subcortical structures implicates a more integrated, hierarchically organized network underlying music processing within the brain. PMID:23717294

  11. Current knowledge on mycolic acids in Corynebacterium glutamicum and their relevance for biotechnological processes.

    PubMed

    Lanéelle, Marie-Antoinette; Tropis, Maryelle; Daffé, Mamadou

    2013-12-01

    Corynebacterium glutamicum is the world's largest producer of glutamate and lysine. Industrial glutamate overproduction is induced by empirical processes, such as biotin limitation, supplementation with specific surfactants or addition of sublethal concentration of certain antibiotics to the culture media. Although Gram-positive bacteria, C. glutamicum and related bacterial species and genera contain, in addition to the plasma membrane, an outer permeability membrane similar to that of Gram-negative microorganisms. As the amino acids have to cross both membranes, their integrity, composition and fluidity influence the export process. While the precise mechanism of the export of the amino acids by C. glutamicum is not fully understood, the excretion of amino acids through the inner membrane involved at least a major export system mechanosensitive channel MscS family (MscCG) encoded by NCgl1221. As the various industrial treatments have been shown to affect the lipid content of the bacterial cell, it is strongly believed that defects in the hallmark of the outer membrane, 2-alkyl, 3-hydroxylated long-chain fatty acids (mycolic acids), could be key factors in the glutamate overproduction. This review aims at giving an overview of the current knowledge on mycolic acids structure, biosynthesis and transfer in C. glutamicum and their relevance for amino acid biotechnological production. PMID:24113823

  12. Northeast Atlantic Igneous Province volcanic margin development

    NASA Astrophysics Data System (ADS)

    Mjelde, R.; Breivik, A. J.; Faleide, J. I.

    2009-04-01

    Early Eocene continental breakup in the NE Atlantic Volcanic Province (NAIP) was associated with voluminous extrusive and intrusive magmatism, and initial seafloor spreading produced anomalously thick oceanic crust. Recent publications based on crustal-scale wide-angle seismic data show that there is a positive correlation between igneous crustal thickness (H) and average P-wave velocity (Vp) on all investigated margins in the NAIP. Vp can be used as a proxy for crustal composition, which can be related to the mode of mantle melting. A positive H-Vp correlation indicates that excessive mantle melting the first few million years after breakup was driven by an initial increased temperature that cools off as seafloor spreading develops, consistent with a mantle plume model. Variations in mantle composition can explain excess magmatism, but will generate a negative H-Vp correlation. Active mantle convection may increase the flux of mantle rocks through the melting zone above the rate of passive corner flow, which can also produce excessive magmatism. This would produce little H-Vp correlation, and place the curve lower than the passive flow melting curve in the diagram. We have compiled earlier published results with our own analyses of published and unpublished data from different groups to look for systematic variations in the mantle melting mode along the NAIP margins. Earlier studies (Holbrook et al., 2002, White et al, 2008) on the southeast Greenland conjugate system, indicate that the thick igneous crust of the southern NAIP (SE Greenland ? Hatton Bank) was dominated by increased mantle temperature only, while magmatism closer to the southern side of and including the Greenland-Iceland-Færøy Ridge (GIFR) was created by combined temperature increase and active mantle convection. Recent publications (Breivik et al., 2008, White et al, 2008) north of the GIFR for the Norway Basin segment, indicate temperature dominated magmatism between the Jan Mayen Fracture

  13. Lithium Isotope Systematics of Rift-related Alkaline Igneous Rocks

    NASA Astrophysics Data System (ADS)

    Halama, R.; McDonough, W. F.; Rudnick, R. L.; Trumbull, R.; Klaudius, J.; Keller, J.; Taubald, H.

    2006-05-01

    Intracontinental alkaline igneous rocks from the Proterozoic Gardar Province (Greenland), the Cretaceous Damaraland Province (Namibia), the Tertiary Kaiserstuhl complex (Germany) and from the Holocene volcano Oldoinyo Lengai (Tanzania) were analyzed to characterize Li isotopic compositions of their mantle sources and to determine the processes affecting δ7Li in alkaline igneous rocks. The inferred mantle Li isotope signatures of the primitive alkaline rocks (δ7Li = +1 to +7) are similar to those of present- day MORB, OIB and carbonatites, and appear to be relatively constant in time and space. Gabbros from the Gardar Province define a relatively small field of Li isotope compositions (δ7Li = +4 to +7). Mineral separates (clinopyroxene, plagioclase) mostly overlap with the whole-rock values, which we interpret to reflect the δ7Li of the mantle sources of the gabbros. Mantle-like δ7Li values are also observed for primitive alkaline rocks from the other regions. Li isotope compositions in more differentiated rocks (syenites, phonolites and rhyolites) are highly variable (+11 to -22 per mil) and reflect a diversity of evolutionary processes that may vary from complex to complex. δ7Li values vary independently of Sr and Nd isotope values and indices of differentiation (e.g. MgO content) or weathering (e.g. LOI). Consistently light δ7Li values (+2 to -22) occur in Gardar syenites associated with a carbonatite. These may be explained by weathering and sub-solidus alteration, as indicated by petrographic observations. Alternatively, fluid-assisted diffusion processes, related to a fenitizing fluid from the carbonatite, may have led to extreme Li isotope fractionation. Whole-rock oxygen isotope analyses will be carried out to evaluate interaction with meteoric water, which would be reflected in a decrease in δ18O compared to magmatic values. The heaviest Li isotopic composition (+11 per mil) was obtained for a rhyolite, probably related to the presence of quartz

  14. Development of advanced host cell protein enrichment and detection strategies to enable process relevant spike challenge studies.

    PubMed

    Soderquist, Ryan G; Trumbo, Mihaela; Hart, Roger A; Zhang, Qingchun; Flynn, Gregory C

    2015-01-01

    An orthogonal chromatography methodology for the enrichment of host cell protein (HCP) species relative to monoclonal antibody (mAb) products was developed and applied for the successful enrichment of HCP from post-Protein A process pools for seven different mAb products. An advanced two-dimensional liquid chromatography/mass spectrometry platform (2D-LC/MS(E) ) was utilized to demonstrate that the HCP enriched material was representative, in terms of species content, to pre-enriched process pools. The HCP enrichment methodology was scaled up for two different mAb products, and this process relevant enriched HCP material was used to conduct advanced spike challenge studies to demonstrate the utility of the approach for the understanding of (1) quantitative HCP clearance, (2) individual species clearance, and (3) species clearance redundancy across polishing chromatography steps. The combined ability to enrich process relevant HCP, detect individual HCP species with 2D-LC/MS(E) technology, and conduct advanced challenge studies with process relevant material surmounts prior limitations to high integrity process challenge study implementation, and facilitates significant process understanding for development of risk-based control strategies and strategic process design. This also demonstrates implementation of a foundational strategy for conducting spike-challenge studies using process-relevant impurities isolated from processes of interest using orthogonal approaches. PMID:26014278

  15. Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Villalta, P. W.; Zahniser, M. S.; Nelson, D. D.; Kolb, C. E.

    1998-01-01

    This is the final report for this project. Its purpose is to reduce the uncertainty in rate coefficients for key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring the rate coefficients for the reactions of HO2 + O3, and HO2 + NO2 in the temperature range (200-240 K) relevant to the lower stratosphere. In order to accomplish this, a high pressure turbulent flow tube reactor was built and its flow characteristics were quantified. The instrument was coupled with tunable diode laser spectroscopy for HO2 detection. Room temperature measurements of the HO2 + NO2 rate coefficients over the pressure range of 50-300 torr agree well with previous measurements. Preliminary measurements of the HO2 + O, rate coefficients at 50 - 300 Torr over the temperature range of 208-294 K agree with the NASA evaluation from 294-225 K but deviate significantly (50 % higher) at approximately 210 K.

  16. Biological Production of a Hydrocarbon Fuel Intermediate Polyhydroxybutyrate (Phb) from a Process Relevant Lignocellulosic Derived Sugar

    SciTech Connect

    Wang, Wei; Mohagheghi, Ali; Mittal, Ashutosh; Pilath, Heidi; Johnson, David K.

    2015-03-22

    PHAs are synthesized by many microorganisms to serve as intracellular carbon storage molecules. In some bacterial strains, PHB can account for up to 80% of cell mass. In addition to its application in the packaging sector, PHB also has great potential as an intermediate in the production of hydrocarbon fuels. PHB can be thermally depolymerized and decarboxylated to propene which can be upgraded to hydrocarbon fuels via commercial oligomerization technologies. In recent years a great effort has been made in bacterial production of PHB, yet the production cost of the polymer is still much higher than conventional petrochemical plastics. The high cost of PHB is because the cost of the substrates can account for as much as half of the total product cost in large scale fermentation. Thus searching for cheaper and better substrates is very necessary for PHB production. In this study, we demonstrate production of PHB by Cupriavidus necator from a process relevant lignocellulosic derived sugar stream, i.e., saccharified hydrolysate slurry from pretreated corn stover. Good cell growth was observed on slurry saccharified with advanced enzymes and 40~60% of PHB was accumulated in the cells. The mechanism of inhibition in the toxic hydrolysate generated by pretreatment and saccharification of biomass, will be discussed.

  17. Groundwater in the Earth's critical zone: Relevance to large-scale patterns and processes

    NASA Astrophysics Data System (ADS)

    Fan, Ying

    2015-05-01

    Although we have an intuitive understanding of the behavior and functions of groundwater in the Earth's critical zone at the scales of a column (atmosphere-plant-soil-bedrock), along a toposequence (ridge to valley), and across a small catchment (up to third-order streams), this paper attempts to assess the relevance of groundwater to understanding large-scale patterns and processes such as represented in global climate and Earth system models. Through observation syntheses and conceptual models, evidence are presented that groundwater influence is globally prevalent, it forms an environmental gradient not fully captured by the climate, and it can profoundly shape critical zone evolution at continental to global scales. Four examples are used to illustrate these ideas: (1) groundwater as a water source for plants in rainless periods, (2) water table depth as a driver of plant rooting depth, (3) the accessibility of groundwater as an ecological niche separator, and (4) groundwater as the lower boundary of land drainage and a global driver of wetlands. The implications to understanding past and future global environmental change are briefly discussed, as well as critical discipline, scale, and data gaps that must be bridged in order for us to translate what we learn in the field at column, hillslope and catchment scales, to what we must predict at regional, continental, and global scales.

  18. Alpha-particle capture reactions in inverse kinematics relevant to p-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Ujić, P.; Lagoyannis, A.; Mertzimekis, T. J.; de Oliveira Santos, F.; Harissopulos, S.; Demetriou, P.; Perrot, L.; Stodel, Ch.; Saint-Laurent, M.-G.; Kamalou, O.; Lefebvre-Schuhl, A.; Spyrou, A.; Amthor, M. A.; Grevy, S.; Caceres, L.; Koivisto, H.; Laitinen, M.; Uusitalo, J.; Julin, R.

    2011-10-01

    The first feasibility study of an α-particle capture reaction in inverse kinematics at energies relevant to the p process was performed at the Wien Filter of the LISE spectrometer at GANIL. Hereby, the 4He(78Kr,γ)82Sr reaction was investigated using as target an 4He-implanted thin Al foil. The analysis of the data has shown that the determination of (α,γ) reaction cross sections at rather low energies around 2 MeV/u in inverse kinematics is indeed feasible regarding the high rejection rate of the primary beam, which in the present work was better than a factor of 109. However, the expected position of the recoils of interest was completely masked by particles of currently unknown origin that could hardly be attributed to scattering of the primary beam. The most probable explanation for the origin of these "pollutants" could be microscopic dust particles of 10 μm diameter and less, that are extremely difficult to avoid in standard experimental conditions. Hence, the use of a gas-jet target instead of a solid one is compulsory.

  19. Large igneous provinces and mass extinctions

    NASA Astrophysics Data System (ADS)

    Wignall, P. B.

    2001-03-01

    Comparing the timing of mass extinctions with the formation age of large igneous provinces reveals a close correspondence in five cases, but previous claims that all such provinces coincide with extinction events are unduly optimistic. The best correlation occurs for four consecutive mid-Phanerozoic examples, namely the end-Guadalupian extinction/Emeishan flood basalts, the end-Permian extinction/Siberian Traps, the end-Triassic extinction/central Atlantic volcanism and the early Toarcian extinction/Karoo Traps. Curiously, the onset of eruptions slightly post-dates the main phase of extinctions in these examples. Of the seven post-Karoo provinces, only the Deccan Traps coincide with a mass extinction, but in this case, the nature of the biotic crisis is best reconciled with the effects of a major bolide impact. Intraoceanic volcanism may also be implicated in a relatively minor end-Cenomanian extinction crisis, although once again the main phase of volcanism occurs after the crisis. The link between large igneous province formation and extinctions remains enigmatic; volume of extrusives and extinction intensity are unrelated and neither is there any apparent relationship with the rapidity of province formation. Violence of eruptions (proportions of pyroclastics) also appears unimportant. Six out of 11 provinces coincide with episodes of global warming and marine anoxia/dysoxia, a relationship that suggests that volcanic CO 2 emissions may have an important effect on global climate. Conversely, there is little, if any, geological evidence for cooling associated with continental flood basalt eruptions suggesting little long-term impact of SO 2 emissions. Large carbon isotope excursions are associated with some extinction events and intervals of flood basalt eruption but these are too great to be accounted for by the release of volcanic CO 2 alone. Thus, voluminous volcanism may in some circumstances trigger calamitous global environmental changes (runaway greenhouses

  20. Introduction to the Apollo collections. Part 1: Lunar igneous rocks

    NASA Technical Reports Server (NTRS)

    Mcgee, P. E.; Warner, J. L.; Simonds, C. H.

    1977-01-01

    The basic petrographic, chemical, and age data is presented for a representative suite of igneous rocks gathered during the six Apollo missions. Tables are given for 69 samples: 32 igneous rocks and 37 impactites (breccias). A description is given of 26 basalts, four plutonic rocks, and two pyroclastic samples. The textural-mineralogic name assigned each sample is included.

  1. SMART-1 highlights and relevant studies on early bombardment and geological processes on rocky planets

    NASA Astrophysics Data System (ADS)

    Foing, B. H.; Racca, G. D.; Josset, J. L.; Koschny, D.; Frew, D.; Almeida, M.; Zender, J.; Heather, D.; Peters, S.; Marini, A.; Stagnaro, L.; Beauvivre, S.; Grande, M.; Kellett, B.; Huovelin, J.; Nathues, A.; Mall, U.; Ehrenfreund, P.; McCannon, P.

    2008-08-01

    present here SMART-1 results relevant to the study of the early bombardment and geological processes on rocky planets. Further information and updates on the SMART-1 mission can be found on the ESA Science and Technology web pages, at: http://sci.esa.int/smart-1/.

  2. LANGUAGE EXPERIENCE SHAPES PROCESSING OF PITCH RELEVANT INFORMATION IN THE HUMAN BRAINSTEM AND AUDITORY CORTEX: ELECTROPHYSIOLOGICAL EVIDENCE

    PubMed Central

    Krishnan, Ananthanarayan; Gandour, Jackson T.

    2015-01-01

    Pitch is a robust perceptual attribute that plays an important role in speech, language, and music. As such, it provides an analytic window to evaluate how neural activity relevant to pitch undergo transformation from early sensory to later cognitive stages of processing in a well coordinated hierarchical network that is subject to experience-dependent plasticity. We review recent evidence of language experience-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem and auditory cortex. We present evidence that shows enhanced representation of linguistically-relevant pitch dimensions or features at both the brainstem and cortical levels with a stimulus-dependent preferential activation of the right hemisphere in native speakers of a tone language. We argue that neural representation of pitch-relevant information in the brainstem and early sensory level processing in the auditory cortex is shaped by the perceptual salience of domain-specific features. While both stages of processing are shaped by language experience, neural representations are transformed and fundamentally different at each biological level of abstraction. The representation of pitch relevant information in the brainstem is more fine-grained spectrotemporally as it reflects sustained neural phase-locking to pitch relevant periodicities contained in the stimulus. In contrast, the cortical pitch relevant neural activity reflects primarily a series of transient temporal neural events synchronized to certain temporal attributes of the pitch contour. We argue that experience-dependent enhancement of pitch representation for Chinese listeners most likely reflects an interaction between higher-level cognitive processes and early sensory-level processing to improve representations of behaviorally-relevant features that contribute optimally to perception. It is our view that long

  3. Igneous rocks from Apollo 16 rake samples

    NASA Technical Reports Server (NTRS)

    Dowty, E.; Keil, K.; Prinz, M.

    1974-01-01

    Results are reported for a study of seven holocrystalline feldspathic rocks (including a spinel troctolite and six melt rocks) and one mare basalt clast from the Apollo-16 rake samples. The composition and grain structure of each rock is described in detail. Only the spinel troctolite is considered a good candidate for a primary igneous cumulate formed during the original differentiation of the lunar crust. It is shown that the melt rocks probably resulted from shock melting followed by rapid crystallization of heterogeneous highland material and that compositional variations are probably due to mixing of various amounts of heterogeneous cumulates and KREEP components. It is suggested that the mare basalt clast may have been derived from Mare Fecunditatis, although the nearest mare to the Apollo-16 site is Nectaris.

  4. Number of Waste Package Hit by Igneous Intrusion

    SciTech Connect

    M. Wallace

    2004-10-13

    The purpose of this scientific analysis report is to document calculations of the number of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analyses include disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application (TSPA-LA) for the Yucca Mountain Project (YMP). Igneous activity is a disruptive event that is included in the TSPA-LA analyses. Two igneous activity scenarios are considered: (1) The igneous intrusion groundwater release scenario (also called the igneous intrusion scenario) considers the in situ damage to waste packages or failure of waste packages that occurs if they are engulfed or otherwise affected by magma as a result of an igneous intrusion. (2) The volcanic eruption scenario depicts the direct release of radioactive waste due to an intrusion that intersects the repository followed by a volcanic eruption at the surface. An igneous intrusion is defined as the ascent of a basaltic dike or dike system (i.e., a set or swarm of multiple dikes comprising a single intrusive event) to repository level, where it intersects drifts. Magma that does reach the surface from igneous activity is an eruption (or extrusive activity) (Jackson 1997 [DIRS 109119], pp. 224, 333). The objective of this analysis is to develop a probabilistic measure of the number of waste packages that could be affected by each of the two scenarios.

  5. Large wood storage in streams of the Eastern Italian Alps and the relevance of hillslope processes

    NASA Astrophysics Data System (ADS)

    Rigon, E.; Comiti, F.; Lenzi, M. A.

    2012-01-01

    An understanding of the dynamics of large wood (LW) in mountain channels provides the basis for evaluating natural morphological patterns as well as managing potentially hazardous wood transport during flood events. Few studies have investigated the distribution of LW in managed streams of the Alps across a wide spatial scale. This paper presents extensive field measurements of LW storage and channel morphology carried out in 13 channels of the Eastern Italian Alps with drainage areas ranging from 1.2 to 70 km2, mean bed slope between 0.03 and 0.38, and channel width between 2 and 20 m. More than 9000 LW elements were measured in the 33 reaches surveyed. A geostatistical, geographic information system (GIS)-based model for wood recruitment from hillslope instabilities was also developed and applied to the study basin. LW storage in the study channels results as being much lower than in seminatural basins of comparable size and climate, and only basins characterized by extensive mass wasting processes contain high wood loads with relevant morphological consequences. The statistical analysis of LW storage at the reach scale indicates that unit stream power is apparently the most significant hydromorphological factor influencing LW storage, in agreement with studies in other world regions. However, we argue that the effect of unit stream power on LW storage is not only linked to flow transport capacity but also derives from its association with LW supply and valley morphology. Both the GIS model and statistical tests on field data indicate that hillslope instabilities connected to the channel network dominate the LW recruitment volume and the distribution of in-channel wood storage.

  6. Attentional demand and processing of relevant visual information during simulated driving: a MEG study.

    PubMed

    Fort, Alexandra; Martin, Robert; Jacquet-Andrieu, Armelle; Combe-Pangaud, Chantal; Foliot, Gérald; Daligault, Sébastien; Delpuech, Claude

    2010-12-01

    It is a well-known fact that attention is crucial for driving a car. This innovative study aims to assess the impact of attentional workload modulation on cerebral activity during a simulated driving task using magnetoencephalography (MEG). A car simulator equipped with a steering wheel, turn indicators, an accelerator and a brake pedal has been specifically designed to be used with MEG. Attentional demand has been modulated using a radio broadcast. During half of the driving scenarios, subjects could ignore the broadcast (simple task, ST) and during the other half, they had to actively listen to it in order to answer 3 questions (dual task, DT). Evoked magnetic responses were computed in both conditions separately for two visual stimuli of interest: traffic lights (from green to amber) and direction signs (arrows to the right or to the left) shown on boards. The cortical sources of these activities have been estimated using a minimum-norm current estimates modeling technique. Results show the activation of a large distributed network similar in ST and DT and similar for both the traffic lights and the direction signs. This network mainly involves sensory visual areas as well as parietal and frontal regions known to play a role in selective attention and motor areas. The increase of attentional demand affects the neuronal processing of relevant visual information for driving, as early as the perceptual stage. By demonstrating the feasibility of recording MEG activity during an interactive simulated driving task, this study opens new possibilities for investigating issues regarding drivers' activity. PMID:20920486

  7. Possible Biosphere-Lithosphere Interactions Preserved in Igneous Zircon and Implications for Hadean Earth.

    PubMed

    Trail, Dustin; Tailby, Nicholas D; Sochko, Maggie; Ackerson, Michael R

    2015-07-01

    Granitoids are silicic rocks that make up the majority of the continental crust, but different models arise for the origins of these rocks. One classification scheme defines different granitoid types on the basis of materials involved in the melting/crystallization process. In this end-member case, granitoids may be derived from melting of a preexisting igneous rock, while other granitoids, by contrast, are formed or influenced by melting of buried sedimentary material. In the latter case, assimilated sedimentary material altered by chemical processes occurring at the near surface of Earth-including biological activity-could influence magma chemical properties. Here, we apply a redox-sensitive calibration based on the incorporation of Ce into zircon crystals found in these two rock types, termed sedimentary-type (S-type) and igneous-type (I-type) granitoids. The ∼400 Ma Lachlan Fold Belt rocks of southeastern Australia were chosen for investigation here; these rocks have been a key target used to describe and explore granitoid genesis for close to 50 years. We observe that zircons found in S-type granitoids formed under more reducing conditions than those formed from I-type granitoids from the same terrain. This observation, while reflecting 9 granitoids and 289 analyses of zircons from a region where over 400 different plutons have been identified, is consistent with the incorporation of (reduced) organic matter in the former and highlights one possible manner in which life may modify the composition of igneous minerals. The chemical properties of rocks or igneous minerals may extend the search for ancient biological activity to the earliest period of known igneous activity, which dates back to ∼4.4 billion years ago. If organic matter was incorporated into Hadean sediments that were buried and melted, then these biological remnants could imprint a chemical signature within the subsequent melt and the resulting crystal assemblage, including zircon. PMID

  8. Natural radioactivity and radon exhalation rate in Brazilian igneous rocks.

    PubMed

    Moura, C L; Artur, A C; Bonotto, D M; Guedes, S; Martinelli, C D

    2011-07-01

    This paper reports the natural radioactivity of Brazilian igneous rocks that are used as dimension stones, following the trend of other studies on the evaluation of the risks to the human health caused by the rocks radioactivity as a consequence of their use as cover indoors. Gamma-ray spectrometry has been utilized to determine the (40)K, (226)Ra and (232)Th activity concentrations in 14 rock types collected at different quarries. The following activity concentration range was found: 12.18-251.90 Bq/kg for (226)Ra, 9.55-347.47 Bq/kg for (232)Th and 407.5-1615.0 Bq/kg for (40)K. Such data were used to estimate Ra(eq), H(ex) and I(γ), which were compared with the threshold limit values recommended in literature. They have been exceeded for Ra(eq) and H(ex) in five samples, where the highest indices corresponded to a rock that suffered a process of ductile-brittle deformation that caused it a microbrecciated shape. The exhalation rate of Rn and daughters has also been determined in slabs consisting of rock pieces ~10 cm-long, 5 cm-wide and 3 cm-thick. It ranged from 0.24 to 3.93 Bq/m(2)/h and exhibited significant correlation with eU (=(226)Ra), as expected. The results indicated that most of the studied rocks did not present risk to human health and may be used indoors, even with low ventilation. On the other hand, igneous rocks that yielded indices above the threshold limit values recommended in literature may be used outdoors without any restriction or indoors with ample ventilation. PMID:21459585

  9. Toxicologically Relevant Aldehydes Produced during the Frying Process Are Trapped by Food Phenolics.

    PubMed

    Zamora, Rosario; Aguilar, Isabel; Granvogl, Michael; Hidalgo, Francisco J

    2016-07-13

    The lipid-derived carbonyl trapping ability of phenolic compounds under common food processing conditions was studied by determining the presence of carbonyl-phenol adducts in both onions fried in the laboratory and commercially crispy fried onions. Four carbonyl-phenol adducts produced between quercetin and acrolein, crotonaldehyde, or (E)-2-pentenal were prepared and characterized by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy and high performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-HRMS). The synthesized compounds were 2-(3,4-dihydroxyphenyl)-3,5,8-trihydroxy-9,10-dihydro-4H,8H-pyrano[2,3-f]chromen-4-one (4), 2-(3,4-dihydroxyphenyl)-3,5,8-trihydroxy-10-methyl-9,10-dihydro-4H,8H-pyrano[2,3-f]chromen-4-one (5), 2-(3,4-dihydroxyphenyl)-3,5-dihydroxy-8-methyl-4H,8H-pyrano[2,3-f]chromen-4-one (9), and 2-(3,4-dihydroxyphenyl)-8-ethyl-3,5-dihydroxy-4H,8H-pyrano[2,3-f]chromen-4-one (10). When onions were fried in fresh rapeseed oil spiked with acrolein, crotonaldehyde, and (E)-2-pentenal (2.7 μmol/g of oil), adduct 10 was the major compound produced, and trace amounts of adducts 4 and 5, but not of adduct 9, were also detected. In contrast, compound 4 was the major adduct present in commercially crispy fried onions. Compound 10 was also present to a lower extent, and trace amounts of compound 5, but not of compound 9, were also detected. These data suggested that lipid-derived carbonyl-phenol adducts are formed in food products under standard cooking conditions. They also pointed to a possible protective role of food polyphenols, which might contribute to the removal of toxicologically relevant aldehydes produced during deep-frying, assuming that the formed products are stable during food consumption in the human organism. PMID:27322490

  10. Igneous rock from Severnyi Kolchim (H3) chondrite: Nebular origin

    NASA Technical Reports Server (NTRS)

    Nazarov, M. A.; Brandstaetter, F.; Kurat, G.

    1993-01-01

    The discovery of lithic fragments with compositions and textures similar to igneous differentiates in unequilibrated ordinary chondrites (UOC's) and carbonaceous chondrites (CC's) has been interpreted as to suggest that planetary bodies existed before chondrites were formed. As a consequence, chondrites (except, perhaps CI chondrites) cannot be considered primitive assemblages of unprocessed nebular matter. We report about our study of an igneous clast from the Severnyi Kolchim (H3) chondrite. The results of the study are incompatible with an igneous origin of the clast but are in favor of a nebular origin similar to that of chondrules.

  11. Effect of igneous intrusive bodies on sedimentary thermal maturity

    SciTech Connect

    Wang, X.; Lerche, I.; Walter, C. )

    1989-09-01

    The high temperatures of igneous intrusives cause localized thermal maturity of sediments far in excess of the regional variation. Previous studies have shown that igneous bodies cool in less than about 1 million years for all but the most exceptional geological conditions. Three case studies are provided which show how the increase in thermal maturity around an igneous body can be used to assess the temperature of the intrusive at emplacement and also the time of intrusion. Corollative implications for localized hydrocarbon generation, migration, and accumulation are also discussed briefly.

  12. Automated igneous rock identifiers for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Gulick, V. C.; Morris, R. L.; Gazis, P.; Bishop, J. L.; Alena, R.; Hart, S. D.; Horton, A.

    2003-04-01

    A key task for human or robotic explorers on the surface of Mars is choosing which particular rock or mineral samples should be selected for more intensive study. The usual challenges of such a task are compounded by the lack of sensory input available to a suited astronaut or the limited downlink bandwidth available to a rover. Additional challenges facing a human mission include limited surface time and the similarities in appearance of important minerals (e.g. carbonates, silicates, salts). Yet the choice of which sample to collect is critical. To address this challenge we are developing science analysis algorithms to interface with a Geologist's Field Assistant (GFA) device that will allow robotic or human remote explorers to better sense and explore their surroundings during limited surface excursions [1]. We aim for our algorithms to interpret spectral and imaging data obtained by various sensors. Our algorithms, for example, will identify key minerals, rocks, and sediments from mid-IR, Raman, and visible/near-IR spectra as well as from high-resolution and microscopic images to help interpret data and to provide high-level advice to the remote explorer. A top-level system will consider multiple inputs from raw sensor data output by imagers and spectrometers (visible/near-IR, mid-IR, and Raman) as well as human opinion to identify rock and mineral samples. Our prototype image analysis system identifies some igneous rocks from texture and color information. Spectral analysis algorithms have also been developed that successfully identify quartz, silica polymorphs, calcite, pyroxene, and jarosite from both visible/near-IR and mid-IR spectra. We have also developed spectral recognizers that identify high-iron pyroxenes and iron-bearing minerals using visible/near-IR spectra only. We are building a combined image and spectral database of rocks and minerals with which to continue development of our algorithms. Future plans include developing algorithms to identify

  13. Behavioral and Event-Related-Potential Correlates of Processing Congruent and Incongruent Self-Relevant Information

    ERIC Educational Resources Information Center

    Clark, Sheri L.

    2013-01-01

    People want to be viewed by others as they view themselves. Being confronted with self-relevant information that is either congruent or incongruent with one's self-view has been shown to differentially affect subsequent behavior, memory for the information, and evaluation of the source of the information. However, no research has examined…

  14. On the weathering of Martian igneous rocks

    NASA Technical Reports Server (NTRS)

    Dreibus, G.; Waenke, H.

    1992-01-01

    Besides the young crystallization age, one of the first arguments for the martian origin of shergottite, nakhlite, and chassignite (SNC) meteorites came from the chemical similarity of the meteorite Shergotty and the martian soil as measured by Viking XRF analyses. In the meantime, the discovery of trapped rare gas and nitrogen components with element and isotope ratios closely matching the highly characteristic ratios of the Mars atmosphere in the shock glasses of shergottite EETA79001 was further striking evidence that the SNC's are martian surface rocks. The martian soil composition as derived from the Viking mission, with its extremely high S and Cl concentrations, was interpreted as weathering products of mafic igneous rocks. The low SiO2 content and the low abundance of K and other trace elements in the martian soils point to a mafic crust with a considerably smaller degree of fractionation compared to the terrestrial crust. However, the chemical evolution of the martian regolith and soil in respect to surface reaction with the planetary atmosphere or hydrosphere is poorly understood. A critical point in this respect is that the geochemical evidence as derived from the SNC meteorites suggests that Mars is a very dry planet that should have lost almost all its initially large water inventory during its accretion.

  15. Igneous intrusions in coal-bearing sequences

    SciTech Connect

    Gurevich, A.B.; Shishlov, S.B.

    1987-08-01

    Intrusions of various compositions, sizes, and shapes have been observed in 115 out of 620 coal basins or deposits on all the continents. They are mainly subvolcanic and hypabyssal, with depths of emplacement estimated as ranging from a few hundred meters to 6 km, but usually 3-4 km. Compositionally, 42% are basic, 31% intermediate, 23% acid, and 4% ultrabasic. Mafic (and related) rock types include dolerites, trachydolerites, gabbro-dolerites, gabbro-monzonites, monzonites, diabases, gabbrodiabases, and less often gabbros and basalts (subvolcanic bodies). These mafic intrusions occur in coal formations of various ages from Carboniferous through Neogene, but predominate in Paleozoic (47%) and Cenozoic beds (45%). They also occur in coal formations of all genetic types, apart from those on ancient stable platforms, where there are no signs of intrusive activity. The mafic intrusions are almost everywhere associated with comagmatic lavas and tuffs (mainly in the younger strata), and the coal beds themselves are to some extent enriched in pyroclastic material, particularly in the upper horizons. This paper gives a worldwide review of igneous intrusions in coal beds. 24 references.

  16. Did the Kiruna iron ores form as a result of a metasomatic or igneous process? New U-Pb and Nd data for the iron oxide apatite ores and their host rocks in the Norrbotten region of northern Sweden

    NASA Astrophysics Data System (ADS)

    Westhues, A.; Hanchar, J. M.; Whitehouse, M. J.; Fisher, C. M.

    2012-12-01

    -Pb dating of zircon from both host rock and ore samples confirms a previously documented event around 1880 - 1900 Ma in the Norrbotten region. However, U-Pb in monazite from an ore sample suggests a further event at ca. 1650 Ma, a period of known activity in Fennoscandia. Further investigation and more U-Pb data are needed to confirm those dates and how the iron mineralization is related to those two events. The combination of U-Th-Pb ages, tracer isotopes and trace element abundances at mineral scale (e.g., Lu-Hf in zircon, and Sm-Nd in monazite, apatite, titanite), along with the O isotopic composition of zircon, will be used to decipher whether the Kiruna iron ore deposits are of metasomatic or igneous origin. Overall, the study also intends to develop a predictive model for exploration of similar iron oxide apatite deposits worldwide.

  17. Variations in the Pb isotope composition in polyformational magmatic rocks of the Ketkap-Yuna igneous province of the Aldan Shield: Evidence for mantle-crust interaction

    NASA Astrophysics Data System (ADS)

    Polin, V. F.; Dril, S. I.; Khanchuk, A. I.; Velivetskaya, T. A.; Vladimirova, T. A.; Il'ina, N. N.

    2016-06-01

    The Pb isotope composition of polyformational Mesozoic igneous rocks of the Ketkap-Yuna igneous province (KYIP) and lower crustal metamorphic rocks of the Batomga granite-greenstone area (the complex of the KYIP basement) of the Aldan Shield was studied for the first time. Based on the data obtained, several types of material sources participating in petrogenetic processes were distinguished. The mantle source identified as PREMA is registered in most of the igneous formations and predominates in mafic alkaline rocks. According to the isotope characteristics, the upper crustal source corresponds to a source of the "Orogen" type by the model of "plumbotectonics" or to the average composition of the continental crust by the Stacey-Kramers model. The lower crust is the third material source; however, the type of lower crustal protolith involved in the igneous process is still not defined, which makes difficult to estimate its role in the petrogenetic processes.

  18. Some Environmental Consequences of Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Coffin, M. F.

    2009-12-01

    The formation of large igneous provinces (LIPs)—continental flood basalts, ‘volcanic’ margins, and oceanic plateaus—may impact the atmosphere, oceans, and biosphere by rapidly releasing huge amounts of particulates, magmatic volatiles (CO2, SO2, Cl, F, etc.), and potentially volatiles (CO2, CH4, SO2, etc.) from intruded sediments (e.g., carbonates, organic-rich shales, evaporites). A key factor affecting the magnitude of volatile release is whether eruptions are subaerial or marine; hydrostatic pressure inhibits vesiculation and degassing of relatively soluble volatile components (H2O, S, Cl, F) in deep water submarine eruptions, although low solubility components (CO2, noble gases) are mostly degassed even at abyssal depths. Directly or indirectly, such injections may cause changes in the atmosphere/ocean system that can lead to perturbations of atmosphere/ocean chemistry, circulation, ecology, and biological productivity. These changes can be global in extent, particularly if environmental conditions were at or near a threshold state or tipping point. LIPs may have been responsible for some of the most dramatic and rapid changes in the global environment. For example, between ~145 and ~50 Ma, the global ocean was characterized by chemical and isotopic variations (especially in C and Sr isotope ratios, trace metal concentrations, and biocalcification), relatively high temperatures, high relative sea level, episodic deposition of black shales (oceanic anoxic events), high production of hydrocarbons, mass extinctions of marine organisms, and radiations of marine flora and fauna. Temporal correlations between the intense pulses of igneous activity associated with LIP formation and environmental changes suggest more than pure coincidence. The 1783-84 eruption of Laki on Iceland provides the only historical record of the type of volcanism that constructs transient LIPs. Although Laki produced a basaltic lava flow representing only ~1% of the volume of a typical

  19. Charge Generation and Propagation in Igneous Rocks

    NASA Technical Reports Server (NTRS)

    Freund, Friedemann

    2000-01-01

    Resistivity changes, ground potentials, electromagnetic (EM) and luminous signals prior to or during earthquakes have been reported, in addition to ground uplift and tilt, and to changes in the seismic wave propagation parameters. However, no physical model exists that ties these diverse phenomena together. Through time-resolved impacts experiments it has been observed that, when igneous rocks (gabbro, diorite, granite) are impacted at low velocities (approx. 100 m/sec), highly mobile electronic charge carriers are generated, spreading from a small volume near the impact point, causing electric potentials, EM and light emission. The rock becomes momentarily conductive. When impacted at higher velocities (approx. 1.5 km/sec), the propagation of the P and S waves is registered through the transient piezoelectric response of quartz. At the same time, the rock volume is filled with mobile charge carriers, and a positive surface potential is registered. During the next 1-2 msec the surface potential oscillates, due to electron injection from ground. These observations are consistent with positive holes, e.g. defect electrons in the O(2-) sublattice, that can travel via the O 2p-dominated valence band of the silicate minerals at the speed of a phonon-mediated charge transfer. Before activation, the positive hole charge carriers lay dormant in form of positive hole pairs, PHP, electrically inactive, chemically equivalent to peroxy links in the structures of constituent minerals. PHPs are introduced by way of hydroxyl (O3Si-OH) incorporated into nominally anhydrous minerals when they crystallize in water-laden environments. Given that sound waves of even relatively low intensity appear to cause PHPs dissociation, thus generating mobile positive holes, it is proposed that microfracturing during rock deformation cause PHP dissociation. Depending on where and how much the rock volume is stressed, the positive holes are expected to form fluctuating charge clouds in the

  20. Databases related to Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Ernst, Richard; Pisarevsky, Sergei

    2015-04-01

    Large Igneous Provinces (LIPs) represent large volume (>0.1 Mkm3; often above >1 Mkm3), mainly mafic (-ultramafic) magmatic events of intraplate affinity in both continental and oceanic settings, and are typically of short duration (<5 m.y.) or consist of multiple short pulses over a maximum of a few 10s of m.y. Silicic, carbonatite and kimberlite magmatism may be associated. The young LIP record is dominated by continental flood basalts and oceanic plateaus, but Proterozoic LIPs have typically lost their flood basalt component during erosion, thus exposing the plumbing system of mafic (-ultramafic) dykes, sills and layered intrusions. LIPs occur at a rate of about 1 every 20-30 m.y. back through the Proterozoic, and Archean analogues are also recognized. The LIP record is growing as more events are recognized and the size of known LIPs (even those of those of Mesozoic age) is increasing through targeted U-Pb geochronology. We review databases related to this fast moving field. The LIPs Commission (www.largeigneousprovinces.org) of IAVCEI ongoingly highlights new insights and events through the "LIP of the Month" series. A global 1:5M scale global LIPs ArcGIS database is under construction through Industry and government funded projects (e.g. www.supercontinent.org) and will form a framework for additional thematic databases related to LIPs, including geochemistry, geochronology, and paleomagnetism (GPMDB, MAGIC). LIP databases provide useful constraints for global Precambrian paleogeographic reconstructions, a context for understanding some global and regional environmental changes, and a useful framework for resource exploration (mineral and hydrocarbon). One of the most important aspects of this global LIPs ArcGIS database is that it is integrating data on the volcanic component of LIPs (both flood basalts, and associated ultramafic and silicic volcanism) with data on the plumbing system component in order to develop an understanding of LIPs as an integrated

  1. Active black holes: Relevant plasma structures, regimes and processes involving all phase space

    SciTech Connect

    Coppi, Bruno

    2011-03-15

    The presented theory is motivated by the growing body of experimental information on the characteristics, connected with relevant spectral, time, and space resolutions, of the radiation emission from objects considered as rotating black holes. In the immediate surroundings of these objects, three plasma regions are identified: an innermost Buffer Region, an intermediate Three-regime Region, and a Structured Peripheral Region. In the last region, a Composite Disk Structure made of a sequence of plasma rings corresponding to the formation of closed magnetic surfaces is considered to be present and to allow intermittent accretion flows along the relevant separatrices. The nonlinear 'Master Equation' describing composite disk structures is derived and solved in appropriate asymptotic limits. A configuration, depending on the state of the plasma at the microscopic level: (i) can be excluded from forming given the strongly nonthermal nature of the electron distribution (in momentum space) within the Three-regime Region allowing the onset of a spiral structure; the observed High Frequency Quasi Periodic Oscillations are associated with these tridimensional structures; (ii) may be allowed to propagate to the outer edge of the Buffer Region where successive rings carrying currents in opposite directions are ejected vertically (in opposite directions) and originate the observed jets; or (iii) penetrates in the Three-regime Region and is dissipated before reaching the outer edge of the Buffer Region. The absence of a coherent composite disk structure guiding accretion in the presence of a significant magnetic field background is suggested to characterize quiescent black holes.

  2. Active black holes: Relevant plasma structures, regimes and processes involving all phase space

    NASA Astrophysics Data System (ADS)

    Coppi, Bruno

    2011-03-01

    The presented theory is motivated by the growing body of experimental information on the characteristics, connected with relevant spectral, time, and space resolutions, of the radiation emission from objects considered as rotating black holes. In the immediate surroundings of these objects, three plasma regions are identified: an innermost Buffer Region, an intermediate Three-regime Region, and a Structured Peripheral Region. In the last region, a Composite Disk Structure made of a sequence of plasma rings corresponding to the formation of closed magnetic surfaces is considered to be present and to allow intermittent accretion flows along the relevant separatrices. The nonlinear ``Master Equation'' describing composite disk structures is derived and solved in appropriate asymptotic limits. A ring configuration, depending on the state of the plasma at the microscopic level: (i) can be excluded from forming given the strongly nonthermal nature of the electron distribution (in momentum space) within the Three-regime Region allowing the onset of a spiral structure; the observed High Frequency Quasi Periodic Oscillations are associated with these tridimensional structures; (ii) may be allowed to propagate to the outer edge of the Buffer Region where successive rings carrying currents in opposite directions are ejected vertically (in opposite directions) and originate the observed jets; or (iii) penetrates in the Three-regime Region and is dissipated before reaching the outer edge of the Buffer Region. The absence of a coherent composite disk structure guiding accretion in the presence of a significant magnetic field background is suggested to characterize quiescent black holes.

  3. Geology is the Key to Explain Igneous Activity in the Mediterranean Area

    NASA Astrophysics Data System (ADS)

    Lustrino, M.

    2014-12-01

    Igneous activity in tectonically complex areas can be interpreted in many different ways, producing completely different petrogenetic models. Processes such as oceanic and continental subduction, lithospheric delamination, changes in subduction polarity, slab break-off and mantle plumes have all been advocated as causes for changes in plate boundaries and magma production, including rate and temporal distribution, in the circum-Mediterranean area. This region thus provides a natural laboratory to investigate a range of geodynamic and magmatic processes. Although many petrologic and tectonic models have been proposed, a number of highly controversial questions still remain. No consensus has yet been reached about the capacity of plate-tectonic processes to explain the origin and style of the magmatism. Similarly, there is still not consensus on the ability of geochemical and petrological arguments to reveal the geodynamic evolution of the area. The wide range of chemical and mineralogical magma compositions produced within and around the Mediterranean, from carbonatites to strongly silica-undersaturated silico-carbonatites and melilitites to strongly silica-oversaturated rhyolites, complicate models and usually require a large number of unconstrained assumptions. Can the calcalkaline-sodic alkaline transition be related to any common petrogenetic point? Is igneous activity plate-tectonic- (top-down) or deep-mantle-controlled (bottom-up)? Do the rare carbonatites and carbonate-rich igneous rocks derive from the deep mantle or a normal, CO2-bearing upper mantle? Do ultrapotassic compositions require continental subduction? Understanding chemically complex magmas emplaced in tectonically complex areas require open minds, and avoiding dogma and assumptions. Studying the geology and shallow dynamics, not speculating about the deep lower mantle, is the key to understanding the igneous activity.

  4. Geochemical and modal data for igneous rocks associated with epithermal mineral deposits

    USGS Publications Warehouse

    du Bray, Edward A.

    2014-01-01

    The purposes of this report are to (1) present available geochemical and modal data for igneous rocks associated with epithermal mineral deposits and (2) to make those data widely and readily available for subsequent, more in-depth consideration and interpretation. Epithermal precious and base-metal deposits are commonly associated with subduction-related calc-alkaline to alkaline arc magmatism as well as back-arc continental rift magmatism. These deposits form in association with compositionally diverse extrusive and intrusive igneous rocks. Temperature and depth regimes prevailing during deposit formation are highly variable. The deposits form from hydrothermal fluids that range from acidic to near-neutral pH, and they occur in a variety of structural settings. The disparate temperature, pressure, fluid chemistry, and structural controls have resulted in deposits with wide ranging characteristics. Economic geologists have employed these characteristics to develop classification schemes for epithermal deposits and to constrain the important genetic processes responsible for their formation.

  5. Kinetics of elementary processes relevant to incipient soot formation. Final technical report

    SciTech Connect

    Lin, M.C.

    1998-03-09

    In order to better understand the mechanism of soot formation (one of the most challenging problems in the study of hydrocarbon combustion chemistry), reliable rate constants for the key reaction steps involved in the formation and polymerization of aromatic hydrocarbons in the inception stage are required for kinetic modeling. In this DOE sponsored work, the authors have developed three new experimental methods: cavity ring-down (CRD) spectrometry, pyrolysis/Fourier transform infrared spectrometry (p/FTIRS) and pulsed laser photolysis/mass spectrometry (PLP/MS) for kinetic measurements of C{sub 6}H{sub 5} reactions pivotal to incipient soot formation chemistry. In addition, the authors have also carried out ab initio molecular orbital (MO) calculations for several key elementary combustion reactions relevant to soot formation. The results are briefly summarized in the report using selected examples for more detailed discussion. 84 refs.

  6. Connecting Organic Aerosol Climate-Relevant Properties to Chemical Mechanisms of Sources and Processing

    SciTech Connect

    Thornton, Joel

    2015-01-26

    The research conducted on this project aimed to improve our understanding of secondary organic aerosol (SOA) formation in the atmosphere, and how the properties of the SOA impact climate through its size, phase state, and optical properties. The goal of this project was to demonstrate that the use of molecular composition information to mechanistically connect source apportionment and climate properties can improve the physical basis for simulation of SOA formation and properties in climate models. The research involved developing and improving methods to provide online measurements of the molecular composition of SOA under atmospherically relevant conditions and to apply this technology to controlled simulation chamber experiments and field measurements. The science we have completed with the methodology will impact the simulation of aerosol particles in climate models.

  7. The Role of the Auditory Brainstem in Processing Linguistically-Relevant Pitch Patterns

    ERIC Educational Resources Information Center

    Krishnan, Ananthanarayan; Gandour, Jackson T.

    2009-01-01

    Historically, the brainstem has been neglected as a part of the brain involved in language processing. We review recent evidence of language-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem. We argue that there is enhancing…

  8. Paleomagnetism of large igneous provinces: case-study from West Greenland, North Atlantic igneous province

    NASA Astrophysics Data System (ADS)

    Riisager, Janna; Riisager, Peter; Pedersen, Asger Ken

    2003-09-01

    We present new paleomagnetic and multi-model stereo photogrammetry data from lava sequences in the West Greenland part of the North Atlantic igneous province (NAIP). The joint analyses of paleomagnetic and photogrammetric data yield a well-defined paleomagnetic pole located at Lat=73.6°N, Long=160.5°E ( N=44, α95=6.2°, K=13.1; age ˜61-55 Ma), which is statistically indistinguishable from a pole recently obtained for the Eurasian part of the NAIP on Faroe Islands [Riisager et al., Earth Planet. Sci. Lett. 201 (2002) 261-276]. Combining the two datasets we obtain a joint NAIP paleomagnetic pole in Greenland coordinates: Lat=71.1°N, Long=161.1°E ( N=87, α95=4.3°, K=13.6; age ˜61-54 Ma). The results presented here represent the first study in which photogrammetry profiles were photographed at the exact same locations where paleomagnetic fieldwork was carried out, and a direct flow-to-flow comparison of the two datasets is possible. Photogrammetry is shown to be particularly useful because of (i) highly precise dip/strike measurements and (ii) detailed 'field observations' that can be made in the laboratory. Highly precise determination of the structural attitude of well-exposed Kanisut Mb lava sequences demonstrates that their apparently reliable in-field dip/strike measurements typically are up to ˜6° wrong. Erroneous dip/strike readings are particularly problematic as they offset paleomagnetic poles without affecting their confidence limits. Perhaps more important for large igneous provinces is the recognition of a variable temporal relationship between consecutive lava flows. We demonstrate how correct interpretation of paleosecular variation, facilitated by the detailed photogrammetry analysis, is crucial for the rapidly emplaced Vaigat Formation lavas. Inaccurate tectonic correction, non-averaged paleosecular variation and unrecognized excursional directions may, perhaps, explain why coeval paleomagnetic poles from large igneous provinces are often

  9. Adamantane derivatives of sulfonamides: sublimation, solubility, solvation and transfer processes in biologically relevant solvents.

    PubMed

    Perlovich, G L; Volkova, T V; Sharapova, A V; Kazachenko, V P; Strakhova, N N; Proshin, A N

    2016-04-01

    Eight adamantane derivatives of sulfonamides were synthesized and characterized. Temperature dependencies of saturation vapor pressure were obtained using the transpiration method and thermodynamic functions of the sublimation processes were calculated. Solubility values of the selected compounds in buffer (pH 7.4), 1-octanol and 1-hexane were determined at different temperatures using the isothermal saturation method. Thermophysical characteristics of fusion processes (melting points and fusion enthalpies) of the substances were studied using the DSC method. Transfer processes from buffer to 1-octanol, from buffer to 1-hexane and 1-hexane to 1-octanol were analyzed. The impact of the molecules' structural modification on sublimation, solubility and solvation/hydration processes in the solvents was studied. Correlation equations connecting the thermodynamic functions with physicochemical descriptors were obtained. PMID:26976747

  10. Behavioral Recommendations in Health Research News as Cues to Action: Self-Relevancy and Self-Efficacy Processes.

    PubMed

    Chang, Chingching

    2016-08-01

    This study argues that behavioral recommendations in health news function as cues to action. A proposed self-oriented model seeks to explore the impacts of behavioral recommendations in health research news as cues to action through their influences on self-relevancy and self-efficacy. A content analysis (Study 1) first establishes that health research news commonly features behavioral recommendations. A message experiment (Study 2) then explores the utility of behavioral recommendations as cues to action by demonstrating a self-relevancy effect: Health research news with, as opposed to without, behavioral recommendations increases the self-relevancy of advocated health behaviors, which then improve people's attitudes toward and intentions to adopt those behaviors. A second message experiment (Study 3) tests whether varying presentations of behavioral recommendations alter their effectiveness as cues to action and thus people's behavioral intentions through a dual effect process. In addition to the previously demonstrated self-relevancy effect, this experiment shows that concrete, as opposed to abstract, behavioral recommendations trigger a self-efficacy effect, increasing perceived self-efficacy and further improving behavioral intentions. PMID:27442057

  11. A Model of Auditory-Cognitive Processing and Relevance to Clinical Applicability.

    PubMed

    Edwards, Brent

    2016-01-01

    Hearing loss and cognitive function interact in both a bottom-up and top-down relationship. Listening effort is tied to these interactions, and models have been developed to explain their relationship. The Ease of Language Understanding model in particular has gained considerable attention in its explanation of the effect of signal distortion on speech understanding. Signal distortion can also affect auditory scene analysis ability, however, resulting in a distorted auditory scene that can affect cognitive function, listening effort, and the allocation of cognitive resources. These effects are explained through an addition to the Ease of Language Understanding model. This model can be generalized to apply to all sounds, not only speech, representing the increased effort required for auditory environmental awareness and other nonspeech auditory tasks. While the authors have measures of speech understanding and cognitive load to quantify these interactions, they are lacking measures of the effect of hearing aid technology on auditory scene analysis ability and how effort and attention varies with the quality of an auditory scene. Additionally, the clinical relevance of hearing aid technology on cognitive function and the application of cognitive measures in hearing aid fittings will be limited until effectiveness is demonstrated in real-world situations. PMID:27355775

  12. Strain fabric evolution within and near deformed igneous sheets: The Sudbury Igneous Complex, Canada

    NASA Astrophysics Data System (ADS)

    Lenauer, Iris; Riller, Ulrich

    2012-08-01

    Deformation structures differing in style and orientation within a given terrane are often attributed to distinct tectono-metamorphic events. However, mechanical heterogeneities may locally cause strain perturbations that can have a profound effect on the geometry of such structures. Here we document highly variable orientations of planar structures, metre- to kilometre-scale folds and shortening directions inferred from brittle fault analysis within the synclinal and layered Sudbury Igneous Complex (SIC) and its Huronian host rocks. NW-SE shortening during Palaeoproterozoic deformation led to the formation of planar structures in the host rocks that are parallel to the NE-SW striking contact of the southern SIC. During deformation, local contact-parallel shortening became more important than regional NW-SE shortening and generated contact-orthogonal planar mineral fabrics and folds. Local contact-parallel shortening is attributed to the shape change of the southern SIC from a convex outward to a concave inward curvi-planar geometry. Contact-parallel shortening accounts for the formation of a previously unidentified kilometre-scale buckle fold in the SIC and respective axial-planar mineral fabrics in Huronian host rocks. This buckle fold shares similar structural characteristics with known higher-order buckle folds of the eastern SIC. We suggest that non-cylindrical buckling and associated mineral fabric development accommodated the shape change of the SIC. This resulted in mutually perpendicular fabric orientations, which are compatible with overall NW-SE shortening. The original shape of the SIC seems to have had a profound influence particularly on the geometry of metamorphic foliations. Our structural analysis supports earlier structural studies advocating that highly discordant planar strain fabrics can be generated by local strain perturbations near igneous sheets under uniform regional shortening.

  13. Magnetostratigraphy of the Etendeka Large Igneous Province, Namibia.

    NASA Astrophysics Data System (ADS)

    Dodd, S. C.; Muxworthy, A. R.; Mac Niocaill, C.

    2014-12-01

    The Paraná - Etendeka large igneous province (≈ 135 Ma) has not been linked to a known mass extinction event, despite large igneous provinces being postulated as a cause. The reason why some large igneous provinces appear the cause of huge fluctuations in the global biosphere, an example being the link between Siberian trap volcanism and the Permo-Triassic boundary, while others seem to have only a minor effect is still debated. Establishing detailed histories of these large igneous provinces is important for understanding why such variations in effect may occur. Why does the volume of the province not reflect the magnitude of the effects seen? During the early Cretaceous, reversals of Earth's magnetic field were more frequent than at other times in Earth's history. Magnetostratigraphy is therefore a tool capable of providing high resolution constraints on the history and duration of the Paraná - Etendeka large igneous province volcanism. Detailed sampling of the Etendeka volcanic stratigraphy, followed by progressive demagnetisation of 893 specimens, yields 70 individual polarities gained from throughout the central volcanic succession. Correlation of the individual sections sampled reveals a minimum of 16 separate polarities are recorded. Subsequent links to the geomagnetic polarity timescale suggest a minimum province duration of > 1 Myrs, with no obvious period of short, high volume volcanism as is often suggested. A protracted duration (>1Myr) may therefore provide the reason why at least the Paraná - Etendeka appears to have no associated extinction event.

  14. Origins of large igneous provinces: Thermal or chemical? (Invited)

    NASA Astrophysics Data System (ADS)

    Korenaga, J.

    2010-12-01

    Large igneous provinces such as continental flood basalts and oceanic plateaus are commonly believed to be caused by massive thermal anomalies in the mantle, or more specifically, mantle plume heads possibly rising from the core-mantle boundary. The existence of such plume heads is more elusive than that of mantle plumes, because there is no currently ongoing formation of continental flood basalt or oceanic plateau, so potential evidence for plume heads must come from the detailed analysis of their fossil traces, i.e., their melting products represented as igneous crust. Compared to petrological and geochemical inference based on surface lavas, seismological studies on large igneous provinces have the advantage of probing the entire crustal section, thereby providing potentially more robust constraints on primary melt composition and the nature of the source mantle. In this talk, I will review the debates over the North Atlantic igneous province, which includes the Iceland hotspot, as well as discuss the prospects of studying oceanic plateaus for providing key information to resolve the origins of large igneous provinces.

  15. Fundamental processes in sputtering of relevance to the fabrication of thin film solar cells

    NASA Astrophysics Data System (ADS)

    Thornton, John A.

    1987-08-01

    Atomic-level processes which occur during the deposition of thin films by sputtering, that influence film properties, are discussed, with special attention given to the deposition of the semiconducting coatings of CuInSe2 and amorphous hydrogenated silicon (a-Si:H) by reactive sputtering. Experiments designed to investigate the critical issues in CuInSe2 and a-Si:H reactive sputtering are described, including a hybrid CuInSe2-deposition process which combines sputtered fluxes of Cu and In with an evaporated flux of Se, thereby avoiding the use of the extremely toxic H2Se. None of the processes discussed appears to preclude the fabrication of high-quality CuInSe2 and a-Si:H films by reactive sputtering.

  16. Chemical transformations of complex mixtures relevant to atmospheric processes: Laboratory and ambient studies

    NASA Astrophysics Data System (ADS)

    Samy, Shahryar (Shar)

    The study of atmospheric chemistry and chemical transformations, which are relevant to conditions in the ambient atmosphere require the investigation of complex mixtures. In the atmosphere, complex mixtures (e.g. diesel emissions) are continually evolving as a result of physical and chemical transformations. This dissertation examines the transformations of modern diesel emissions (DE) in a series of experiments conducted at the European Outdoor Simulation Chamber (EUPHORE) in Valencia, Spain. Experimental design challenges are addressed, and the development of a NOx removal technology (denuder) is described with results from the application of the newly developed NOx denuder in the most recent EUPHORE campaign (2006). In addition, the data from an ambient aerosol study that examines atmospheric transformation products is presented and discussed. Atmospheric transformations of DE and associated secondary organic aerosol (SOA) production, along with chemical characterization of polar organic compounds (POC) in the EUPHORE experiments, provides a valuable insight on the tranformations of modern DE in environmentally relevant atmospheres. The greatest SOA production occurred in DE with toluene addition experiments (>40%), followed by DE with HCHO (for OH radical generation) experiments. A small amount of SOA (3%) was observed for DE in dark with N2O5 (for NO3 radical production) experiments. Distinct POC formation in light versus dark experiments suggests the role of OH initiated reactions in these chamber atmospheres. A trend of increasing concentrations of dicarboxylic acids in light versus dark experiments was observed when evaluated on a compound group basis. The production of diacids (as a compound group) demonstrates a consistent indicator for photochemical transformation in relation to studies in the ambient atmosphere. The four toluene addition experiments in this study were performed at different [tol]o/[NOx]o ratios and displayed an average SOA %yield (in

  17. Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance.

    PubMed

    Calder, Philip C

    2015-04-01

    Inflammation is a condition which contributes to a range of human diseases. It involves a multitude of cell types, chemical mediators, and interactions. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 (n-3) fatty acids found in oily fish and fish oil supplements. These fatty acids are able to partly inhibit a number of aspects of inflammation including leukocyte chemotaxis, adhesion molecule expression and leukocyte-endothelial adhesive interactions, production of eicosanoids like prostaglandins and leukotrienes from the n-6 fatty acid arachidonic acid, production of inflammatory cytokines, and T-helper 1 lymphocyte reactivity. In addition, EPA gives rise to eicosanoids that often have lower biological potency than those produced from arachidonic acid and EPA and DHA give rise to anti-inflammatory and inflammation resolving mediators called resolvins, protectins and maresins. Mechanisms underlying the anti-inflammatory actions of marine n-3 fatty acids include altered cell membrane phospholipid fatty acid composition, disruption of lipid rafts, inhibition of activation of the pro-inflammatory transcription factor nuclear factor kappa B so reducing expression of inflammatory genes, activation of the anti-inflammatory transcription factor peroxisome proliferator activated receptor γ and binding to the G protein coupled receptor GPR120. These mechanisms are interlinked, although the full extent of this is not yet elucidated. Animal experiments demonstrate benefit from marine n-3 fatty acids in models of rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and asthma. Clinical trials of fish oil in RA demonstrate benefit, but clinical trials of fish oil in IBD and asthma are inconsistent with no overall clear evidence of efficacy. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance". PMID:25149823

  18. Investigations of Physical Processes in Microgravity Relevant to Space Electrochemical Power Systems

    NASA Technical Reports Server (NTRS)

    Lvovich, Vadim F.; Green, Robert; Jakupca, Ian

    2015-01-01

    NASA has performed physical science microgravity flight experiments in the areas of combustion science, fluid physics, material science and fundamental physics research on the International Space Station (ISS) since 2001. The orbital conditions on the ISS provide an environment where gravity driven phenomena, such as buoyant convection, are nearly negligible. Gravity strongly affects fluid behavior by creating forces that drive motion, shape phase boundaries and compress gases. The need for a better understanding of fluid physics has created a vigorous, multidisciplinary research community whose ongoing vitality is marked by the continuous emergence of new fields in both basic and applied science. In particular, the low-gravity environment offers a unique opportunity for the study of fluid physics and transport phenomena that are very relevant to management of fluid - gas separations in fuel cell and electrolysis systems. Experiments conducted in space have yielded rich results. These results provided valuable insights into fundamental fluid and gas phase behavior that apply to space environments and could not be observed in Earth-based labs. As an example, recent capillary flow results have discovered both an unexpected sensitivity to symmetric geometries associated with fluid container shape, and identified key regime maps for design of corner or wedge-shaped passive gas-liquid phase separators. In this presentation we will also briefly review some of physical science related to flight experiments, such as boiling, that have applicability to electrochemical systems, along with ground-based (drop tower, low gravity aircraft) microgravity electrochemical research. These same buoyancy and interfacial phenomena effects will apply to electrochemical power and energy storage systems that perform two-phase separation, such as water-oxygen separation in life support electrolysis, and primary space power generation devices such as passive primary fuel cell.

  19. FINAL REPORT (PART 2). RADIOLYTIC AND THERMAL PROCESSES RELEVANT TO DRY STORAGE OF SPENT NUCLEAR FUELS

    EPA Science Inventory

    The focus of our experimental research activities at Rutgers University was to characterize the effects of temperature and radiation processes on the interactions of H2O with oxide surfaces. Our experiments focused on the fundamental interaction of H2O molecules with surfaces of ...

  20. FINAL PROGRESS REPORT. RADIOLYTIC AND THERMAL PROCESSES RELEVANT TO DRY STORAGE OF SPENT NUCLEAR FUELS

    EPA Science Inventory

    The focus of our experimental research activities at Rutgers University was to characterize the effects of temperature and radiation processes on the interactions of H2O with oxide surfaces. Our experiments focused on the fundamental interaction of H2O molecules with surfaces of ...

  1. Structure, Content, and Process in Teacher Training: The Relevance of Copernicus, Gardner, and Dewey.

    ERIC Educational Resources Information Center

    Soares, Louise M.

    1998-01-01

    Argues that a unique combination of (1) the Copernican Plan for block scheduling; (2) the application of Howard Gardner's theory of multiple intelligences; and (3) John Dewey's basic ideas about process create a teacher training program in which mastery is an achievable goal. Describes each component and illustrates how each has worked in one…

  2. Correlation of palaeomagnetic directions constrains eruption rate of large igneous provinces

    NASA Astrophysics Data System (ADS)

    Suttie, Neil; Biggin, Andrew J.; Holme, Richard

    2014-02-01

    The rate of eruption of lava flows in large igneous provinces is a highly controversial topic with implications for the processes by which mass extinctions of life occurred throughout the Phanerozoic. It is also an extremely difficult parameter to measure, but may be accessed through the correlation of palaeomagnetic directions recorded in neighbouring lava flows. The next-neighbour correlation can be described by a single additional parameter which can be evaluated by constructing a suitable covariance matrix. It is found to be a useful proxy for the rate of eruption of Cenozoic lavas from the North Atlantic igneous province and has the potential to help constrain the eruptive histories of other large igneous provinces. Significant next-neighbour correlation is revealed even in the absence of grouping of directions, giving a method of detecting changing eruption rates when there are no magnetostratigraphic markers. Significant correlation is found over timescales of tens of thousands of years in volcanic datasets making it doubtful that records of recent secular variation over shorter timescales can be used as a model for palaeosecular variation. By eliminating next-neighbour correlation, it is demonstrated how estimates of palaeosecular variation may be derived, with formal confidence limits, allowing robust comparisons to be made between sites. Using this method we show that the angular dispersion of the field dropped significantly during the 2.5 million year long polarity chron C24r.

  3. The Central-Western Mediterranean: Anomalous igneous activity in an anomalous collisional tectonic setting

    NASA Astrophysics Data System (ADS)

    Lustrino, Michele; Duggen, Svend; Rosenberg, Claudio L.

    2011-01-01

    The central-western Mediterranean area is a key region for understanding the complex interaction between igneous activity and tectonics. In this review, the specific geochemical character of several 'subduction-related' Cenozoic igneous provinces are described with a view to identifying the processes responsible for the modifications of their sources. Different petrogenetic models are reviewed in the light of competing geological and geodynamic scenarios proposed in the literature. Plutonic rocks occur almost exclusively in the Eocene-Oligocene Periadriatic Province of the Alps while relatively minor plutonic bodies (mostly Miocene in age) crop out in N Morocco, S Spain and N Algeria. Igneous activity is otherwise confined to lava flows and dykes accompanied by relatively greater volumes of pyroclastic (often ignimbritic) products. Overall, the igneous activity spanned a wide temporal range, from middle Eocene (such as the Periadriatic Province) to the present (as in the Neapolitan of southern Italy). The magmatic products are mostly SiO 2-oversaturated, showing calcalkaline to high-K calcalcaline affinity, except in some areas (as in peninsular Italy) where potassic to ultrapotassic compositions prevail. The ultrapotassic magmas (which include leucitites to leucite-phonolites) are dominantly SiO 2-undersaturated, although rare, SiO 2-saturated (i.e., leucite-free lamproites) appear over much of this region, examples being in the Betics (southeast Spain), the northwest Alps, northeast Corsica (France), Tuscany (northwest Italy), southeast Tyrrhenian Sea (Cornacya Seamount) and possibly in the Tell region (northeast Algeria). Excepted for the Alpine case, subduction-related igneous activity is strictly linked to the formation of the Mediterranean Sea. This Sea, at least in its central and western sectors, is made up of several young (< 30 Ma) V-shaped back-arc basins plus several dispersed continental fragments, originally in crustal continuity with the European

  4. Preferential processing of self-relevant stimuli occurs mainly at the perceptual and conscious stages of information processing.

    PubMed

    Tacikowski, P; Ehrsson, H H

    2016-04-01

    Self-related stimuli, such as one's own name or face, are processed faster and more accurately than other types of stimuli. However, what remains unknown is at which stage of the information processing hierarchy this preferential processing occurs. Our first aim was to determine whether preferential self-processing involves mainly perceptual stages or also post-perceptual stages. We found that self-related priming was stronger than other-related priming only because of perceptual prime-target congruency. Our second aim was to dissociate the role of conscious and unconscious factors in preferential self-processing. To this end, we compared the "self" and "other" conditions in trials where primes were masked or unmasked. In two separate experiments, we found that self-related priming was stronger than other-related priming but only in the unmasked trials. Together, our results suggest that preferential access to the self-concept occurs mainly at the perceptual and conscious stages of the stimulus processing hierarchy. PMID:26930161

  5. The Relevance Of The Preform Design In Coining Processes Of Cupronickel Alloy

    SciTech Connect

    Buffa, G.; Fratini, L.; Micari, F.

    2007-05-17

    Coining is a forging process in which a metallic disk, characterized by a low volume-surface ratio, is deformed with the aim to impress 3D images on its three surfaces. Due to the large production volumes and, at the same time, to the high quality standards required to the final products in terms of final dimensions, tolerances and surface finishing, such closed-die, cold forging process requires a careful evaluation and choice of the proper operative parameters. In particular, along with technological parameters as the die velocity, die stroke and lubrication, which, in turn, contribute to affect the pressure values on the die surfaces, and thus the press choice, geometrical parameters as the side ring inner diameter and, above all, the preform geometry, strongly affect the quality of the obtained parts. In this paper, a 3D FEM model for coining processes is proposed, that is Lagrangian implicit, rigid-viscoplastic. The relationships between the obtained geometry and the starting preform shape is numerically investigated, allowing, through the analysis of the effective stresses, strain, and strain rate on the coin, as well as of the loads on the dies, to highlight the significance of the perform design in order to obtain a final product that satisfies the strict geometrical tolerances required. It is found that the best results on the final part are obtained with chamfered preform geometries, though larger values of force on the dies are observed.

  6. The Relevance Of The Preform Design In Coining Processes Of Cupronickel Alloy

    NASA Astrophysics Data System (ADS)

    Buffa, G.; Fratini, L.; Micari, F.

    2007-05-01

    Coining is a forging process in which a metallic disk, characterized by a low volume-surface ratio, is deformed with the aim to impress 3D images on its three surfaces. Due to the large production volumes and, at the same time, to the high quality standards required to the final products in terms of final dimensions, tolerances and surface finishing, such closed-die, cold forging process requires a careful evaluation and choice of the proper operative parameters. In particular, along with technological parameters as the die velocity, die stroke and lubrication, which, in turn, contribute to affect the pressure values on the die surfaces, and thus the press choice, geometrical parameters as the side ring inner diameter and, above all, the preform geometry, strongly affect the quality of the obtained parts. In this paper, a 3D FEM model for coining processes is proposed, that is Lagrangian implicit, rigid-viscoplastic. The relationships between the obtained geometry and the starting preform shape is numerically investigated, allowing, through the analysis of the effective stresses, strain, and strain rate on the coin, as well as of the loads on the dies, to highlight the significance of the perform design in order to obtain a final product that satisfies the strict geometrical tolerances required. It is found that the best results on the final part are obtained with chamfered preform geometries, though larger values of force on the dies are observed.

  7. Mesotrypsin and caspase-14 participate in prosaposin processing: potential relevance to epidermal permeability barrier formation.

    PubMed

    Yamamoto-Tanaka, Mami; Motoyama, Akira; Miyai, Masashi; Matsunaga, Yukiko; Matsuda, Junko; Tsuboi, Ryoji; Hibino, Toshihiko

    2014-07-18

    A proteomics-based search for molecules interacting with caspase-14 identified prosaposin and epidermal mesotrypsin as candidates. Prosaposin is a precursor of four sphingolipid activator proteins (saposins A-D) that are essential for lysosomal hydrolysis of sphingolipids. Thus, we hypothesized that caspase-14 and mesotrypsin participate in processing of prosaposin. Because we identified a saposin A sequence as an interactor with these proteases, we prepared a specific antibody to saposin A and focused on saposin A-related physiological reactions. We found that mesotrypsin generated saposins A-D from prosaposin, and mature caspase-14 contributed to this process by activating mesotrypsinogen to mesotrypsin. Knockdown of these proteases markedly down-regulated saposin A synthesis in skin equivalent models. Saposin A was localized in granular cells, whereas prosaposin was present in the upper layer of human epidermis. The proximity ligation assay confirmed interaction between prosaposin, caspase-14, and mesotrypsin in the granular layer. Oil Red staining showed that the lipid envelope was significantly reduced in the cornified layer of skin from saposin A-deficient mice. Ultrastructural studies revealed severely disorganized cornified layer structure in both prosaposin- and saposin A-deficient mice. Overall, our results indicate that epidermal mesotrypsin and caspase-14 work cooperatively in prosaposin processing. We propose that they thereby contribute to permeability barrier formation in vivo. PMID:24872419

  8. Mechanistic study of the Polymer-Induced Liquid-Precursor (PILP) process: Relevance to biomineralization

    NASA Astrophysics Data System (ADS)

    Dai, Lijun

    Biomineralization is a process in which cells construct a mineralization platform based on framework proteins and water-soluble proteins, and utilize some transportation vesicles, such as matrix vesicles to regulate the transportation of ions and precursor phases. The mineral morphologies formed by the Polymer-Induced Liquid-Precursor (PILP) process, which utilizes acidic polypeptides or polymers to mimic the acidic proteins in biominerals, have been shown to have a great similarity with many biominerals. This drives us to investigate the important factors and underlying mechanisms governing the generation, stabilization and transformation of polymer-induced liquid-precursor phases. First, the PILP phase composition has been characterized during a reaction time series using a combination of measuring water loss with elemental analysis. This phase is found to be a highly hydrated phase with a large amount of acidic polymers entrapped within. By FT-Raman, it is found that these acidic polymers can chelate with calcium ions by breaking the initial calcium-water complexes, liberating free water near the calcium-polymer complexes. It is then shown that when calcium carbonate complexes are formed, most of the acidic polymer can be liberated from the formed precursor phase to re-induce more PILP phase. By FTIR, it is found that acidic polymers can stabilize the PILP amorphous phase. The extended stabilization lifetime of the PILP phase is due to the entrapped acidic polymers and the free water in the precursor phase. They disrupt the ordered packing of the calcium carbonate complexes. Second, to investigate how different protein structures would affect the PILP phase quality, quantity, and stability, a series of synthetic peptides mimicking proteins involved in biomineralization were synthesized and applied to generate the PILP process using various techniques. Peptides with high charge density, phosphorylation density and molecular weight to a limit of 5000 Da in

  9. Hydrogen Reduction Kinetics of Hematite Concentrate Particles Relevant to a Novel Flash Ironmaking Process

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Mohassab, Yousef; Jiang, Tao; Sohn, Hong Yong

    2015-04-01

    As an integral part of developing a novel ironmaking process, the hydrogen reduction kinetics of hematite concentrate particles (average particle size 21 µm) were measured in the temperature range from 1423 K to 1623 K (1150 °C to 1350 °C). The novel ironmaking process aims at producing iron from iron oxide concentrates in a flash reactor using gaseous fuels and reductants, which will help reduce energy consumption and minimize greenhouse gas emissions. More than 90 pct reduction of hematite concentrate particles could be obtained by hydrogen at a temperature of 1573 K (1300 °C) and 3 seconds of residence time, indicating that hematite concentrate is suitable for the flash reduction process under development largely aimed at the use of magnetite concentrates. The nucleation and growth rate equation with the Avrami parameter, n, of 1.0 well described the kinetics of hematite reduction. The reduction rate has a 1st-order dependence on the partial pressure of hydrogen. The activation energy of the reaction was 214 kJ/mol, indicating strong temperature dependence. The following complete rate equation was developed that can satisfactorily predict the kinetics of hematite concentrate particles and is suitable for the design of a flash reactor: {{{d}}X}/{{{d}t}} = 4.41 × 107 × {{e}}^{{ - 214{,}000/RT}} × ( {p{{H}}2 - {p{{H}}2 {{O}}}/K} ) × (1 - X), where X is fractional reduction degree, R is 8.314 J/mol K, T is in K, p is in atm, and t is in seconds.

  10. The relevance of individual microphysical processes for potential vorticity anomalies in extratropical cyclones

    NASA Astrophysics Data System (ADS)

    Crezee, Bas; Joos, Hanna; Wernli, Heini

    2016-04-01

    Extratropical cyclones have a large impact on daily weather through their accompanying strong winds and precipitation. The latent heating and cooling associated with microphysical processes like condensation, freezing and melting, sublimation and evaporation leads to the formation of distinct cloud diabatic potential vorticity (CDPV) anomalies. Positive low-level CDPV anomalies - which typically are formed along the fronts and close to the cyclone center - have been shown to interact with upper-level PV anomalies thereby potentially enhancing storm intensification. Here a novel method is applied, which calculates backward trajectories from the mature storm stage, integrates cloud diabatic PV changes due to microphysical processes, and constructs a CDPV budget for each individual anomaly. Thereby we quantify the contributions of, e.g., cloud condensation, depositional growth of snow and melting of snow to the individual anomalies and in turn to the near-surface circulation. First, we apply this method to an idealized mid-latitude cyclone. The formation of the relatively small low-level negative CDPV anomalies is dominated each by one specific process, depending on their location relative to the front. For the large positive PV anomaly we find that the strongest contributions are from in-cloud condensation and below-cloud snow melting and rain evaporation. Although contributions of in-cloud depositional growth of ice are rather small, they cover a very large area and are therefore dynamically significant, i.e., they produce a fairly large-scale but low-amplitude anomaly. In addition the results from the idealized simulations are compared to a wintertime cyclone. It will be discussed how well the method works for real cyclones and how closely the results agree with those from the idealized channel model experiment.

  11. Incorporation of arsenic into gypsum: Relevant to arsenic removal and immobilization process in hydrometallurgical industry.

    PubMed

    Zhang, Danni; Yuan, Zidan; Wang, Shaofeng; Jia, Yongfeng; Demopoulos, George P

    2015-12-30

    Gypsum precipitates as a major secondary mineral during the iron-arsenate coprecipitation process for the removal of arsenic from hydrometallurgical effluents. However, its role in the fixation of arsenic is still unknown. This work investigated the incorporation of arsenic into gypsum quantitatively during the crystallization process at various pHs and the initial arsenic concentrations. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray absorption near edge spectroscopy (XANES) and scanning electron microscopy (SEM) were employed to characterize the coprecipitated solids. The results showed that arsenate was measurably removed from solution during gypsum crystallization and the removal increased with increasing pH. At lower pH where the system was undersaturated with respect to calcium arsenate, arsenate ions were incorporated into gypsum structure, whereas at higher pH, calcium arsenate was formed and constituted the major arsenate bearing species in the precipitated solids. The findings may have important implications for arsenic speciation and stability of the hydrometallurgical solid wastes. PMID:26188870

  12. Uranium and other element analyses of igneous rocks of Arkansas

    SciTech Connect

    Steele, K.F.

    1982-05-01

    Seventy-six samples of igneous rocks representing a variety of rock types and locations in Arkansas were analyzed by neutron activation analysis for the elements U, Th, Na, Al, Sc, Ti, V, Mn, Fe, La, Ce, Sm, Eu, Dy, Yb, Lu, and Hf. Samples were collected from the major igneous intrusions at Granite Mountain, Bauxite, Magnet Cove, Potash Sulfur Springs, and Murfreesboro, representing various syenites, lamprophyres, carbonatite, kimberlite, and periodotite. To make the data available for public use without further delay, this report is being issued without the normal technical and copy editing.

  13. Behavior of Shiga toxigenic Escherichia coli relevant to lettuce washing processes and consideration of factors for evaluating washing process surrogates.

    PubMed

    Deng, Kaiping; Wang, Xue; Yen, Li-Han; Ding, Hongliu; Tortorello, Mary Lou

    2014-11-01

    Postharvest processes for fresh produce commonly include washing in water containing antimicrobial chemicals, such as chlorine; however, if the antimicrobials are not present in sufficient levels, washing can promote the spread of contamination that might be present. To understand cross-contamination risk during washing, we tested a collection of Shiga toxigenic Escherichia coli (STEC), including O157:H7 and other non-O157 strains, for certain traits during washing of fresh-cut lettuce, i.e., sensitivity to sublethal chlorine levels and ability to cross-contaminate (detach from and attach to) lettuce in the presence of sublethal chlorine levels. Nonpathogenic E. coli Nissle 1917 (EcN) and Pediococcus pentosaceus lactic acid bacterial species (LAB) were included as potential washing process validation surrogates. As measured by extension of the lag phase of growth in media containing 0.15 ppm of chlorine, chlorine sensitivity varied among the STECs. Cross-contamination was assessed by evaluating transfer of bacteria from inoculated to uninoculated leaves during washing. Without chlorine, similar transfer to wash water and uninoculated leaves was shown. In 1 ppm of chlorine, cross-contamination was not detected with most strains, except for the substantial transfer by a STEC O111 strain and EcN in some replicates. Strain O111 and EcN showed less inactivation in 0.25 ppm of chlorine water compared with O157 (P < 0.05). LAB showed similar transfer and similar chlorine inactivation to O157. Considering together the sublethal chlorine sensitivity and detachment/attachment traits, neither EcN nor LAB displayed optimal characteristics as washing process surrogates for the STEC strains, although further evaluation is needed. This work demonstrated a range of behaviors of STEC strains during lettuce washing and may be helpful in hazard characterization, identifying factors to consider for evaluating washing process efficacy, and identifying phenotypic traits to select

  14. Cost-Efficient Methods and Processes for Safety Relevant Embedded Systems (CESAR) - An Objective Overview

    NASA Astrophysics Data System (ADS)

    Jolliffe, Graham

    For developing embedded safety critical systems, industrial companies have to face increasing complexity and variety coupled with increasing regulatory constraints, while costs, performances and time to market are constantly challenged. This has led to a profusion of enablers (new processes, methods and tools), which are neither integrated nor interoperable because they have been developed more or less independently (addressing only a part of the complexity: e.g. Safety) in the absence of internationally recognized open standards. CESAR has been established under ARTEMIS, the European Union's Joint Technology Initiative for research in embedded systems, with the aim to improve this situation and this pa-per will explain what CESAR's objectives are, how they are expected to be achieved and, in particular, how current best practice can ensure that safety engineering requirements can be met.

  15. The default network and self-generated thought: component processes, dynamic control, and clinical relevance

    PubMed Central

    Andrews-Hanna, Jessica R.; Smallwood, Jonathan; Spreng, R. Nathan

    2014-01-01

    Though only a decade has elapsed since the default network was first emphasized as being a large-scale brain system, recent years have brought great insight into the network’s adaptive functions. A growing theme highlights the default network as playing a key role in internally-directed—or self-generated—thought. Here, we synthesize recent findings from cognitive science, neuroscience, and clinical psychology to focus attention on two emerging topics as current and future directions surrounding the default network. First, we present evidence that self-generated thought is a multi-faceted construct whose component processes are supported by different subsystems within the network. Second, we highlight the dynamic nature of the default network, emphasizing its interaction with executive control systems when regulating aspects of internal thought. We conclude by discussing clinical implications of disruptions to the integrity of the network, and consider disorders when thought content becomes polarized or network interactions become disrupted or imbalanced. PMID:24502540

  16. Naturalistic observation of health-relevant social processes: the electronically activated recorder methodology in psychosomatics.

    PubMed

    Mehl, Matthias R; Robbins, Megan L; Deters, Fenne Große

    2012-05-01

    This article introduces a novel observational ambulatory monitoring method called the electronically activated recorder (EAR). The EAR is a digital audio recorder that runs on a handheld computer and periodically and unobtrusively records snippets of ambient sounds from participants' momentary environments. In tracking moment-to-moment ambient sounds, it yields acoustic logs of people's days as they naturally unfold. In sampling only a fraction of the time, it protects participants' privacy and makes large observational studies feasible. As a naturalistic observation method, it provides an observer's account of daily life and is optimized for the objective assessment of audible aspects of social environments, behaviors, and interactions (e.g., habitual preferences for social settings, idiosyncratic interaction styles, subtle emotional expressions). This article discusses the EAR method conceptually and methodologically, reviews prior research with it, and identifies three concrete ways in which it can enrich psychosomatic research. Specifically, it can (a) calibrate psychosocial effects on health against frequencies of real-world behavior; (b) provide ecological observational measures of health-related social processes that are independent of self-report; and (c) help with the assessment of subtle and habitual social behaviors that evade self-report but have important health implications. An important avenue for future research lies in merging traditional self-report-based ambulatory monitoring methods with observational approaches such as the EAR to allow for the simultaneous yet methodologically independent assessment of inner, experiential aspects (e.g., loneliness) and outer, observable aspects (e.g., social isolation) of real-world social processes to reveal their unique effects on health. PMID:22582338

  17. Naturalistic Observation of Health-Relevant Social Processes: The Electronically Activated Recorder (EAR) Methodology in Psychosomatics

    PubMed Central

    Mehl, Matthias R.; Robbins, Megan L.; Deters, Fenne große

    2012-01-01

    This article introduces a novel, observational ambulatory monitoring method called the Electronically Activated Recorder or EAR. The EAR is a digital audio recorder that runs on a handheld computer and periodically and unobtrusively records snippets of ambient sounds from participants’ momentary environments. In tracking moment-to-moment ambient sounds, it yields acoustic logs of people’s days as they naturally unfold. In sampling only a fraction of the time, it protects participants’ privacy and makes large observational studies feasible. As a naturalistic observation method, it provides an observer’s account of daily life and is optimized for the objective assessment of audible aspects of social environments, behaviors, and interactions (e.g., habitual preferences for social settings, idiosyncratic interaction styles, and subtle emotional expressions). The article discusses the EAR method conceptually and methodologically, reviews prior research with it, and identifies three concrete ways in which it can enrich psychosomatic research. Specifically, it can (a) calibrate psychosocial effects on health against frequencies of real-world behavior, (b) provide ecological, observational measures of health-related social processes that are independent of self-report, and (c) help with the assessment of subtle and habitual social behaviors that evade self-report but have important health implications. An important avenue for future research lies in merging traditional, self-report based ambulatory monitoring methods with observational approaches such as the EAR to allow for the simultaneous yet methodologically independent assessment of inner, experiential (e.g., loneliness) and outer, observable aspects (e.g., social isolation) of real-world social processes to reveal their unique effects on health. PMID:22582338

  18. Biological processes and optical measurements near the sea surface: Some issues relevant to remote sensing

    NASA Technical Reports Server (NTRS)

    Cullen, John J.; Lewis, Marlon R.

    1995-01-01

    The advent of remote sensing, the develpmemt of new optical instrumentation, and the associated advances in hydrological optics have transformed oceanography; it is now feasible to describe ocean-scale biogeochemical dynamcis from satellite observations, verified and complemented by measurements from optical sensors on profilers, moorings, and drifters. Only near-surface observations are common to both remote sensing and in situ observation, so it is critical to understand processes in the upper euphotic zone. Unfortunately, the biological principles that must be used to interpret optical variability near the sea surface are weaker than we would like, because relatively few experiments and analyses have examined bio-optical relationships under high irradiance characteristic of the upper optical depth. Special consideration of this stratum is justified, because there is good evidence that bio-optical relationships are altered near the surface; (1) the fluorescence yield from chlorophyll declines, leading to bias in the estimation of pigment from fluorometry; (2) the modeled relationship between solar-stimulated fluorecence and photosynthesis seems to deviate significantly from that presented for the lower euphotic zone; and (3) carbon-specific and cellular attenuation cross sections of phytoplankton change substantially during exposures to bright light. Even the measurement of primary productivity is problematic near the sea surface, because vertical mixing is not simulated and artifactual inhibition of photosynthesis can result. These problems can be addressed by focusing more sampling effort, experimental simulation, and analytical consideration on the upper optical depth, and by shortening timescales for the measurement of marine photosynthesis. Special efforts to study near-surface processes are justified, because new bio-optical algorithms will require quantitaitve descriptions of the responses of phytoplankton to bright light.

  19. Translational Rodent Paradigms to Investigate Neuromechanisms Underlying Behaviors Relevant to Amotivation and Altered Reward Processing in Schizophrenia

    PubMed Central

    Young, Jared W.; Markou, Athina

    2015-01-01

    Amotivation and reward-processing deficits have long been described in patients with schizophrenia and considered large contributors to patients’ inability to integrate well in society. No effective treatments exist for these symptoms, partly because the neuromechanisms mediating such symptoms are poorly understood. Here, we propose a translational neuroscientific approach that can be used to assess reward/motivational deficits related to the negative symptoms of schizophrenia using behavioral paradigms that can also be conducted in experimental animals. By designing and using objective laboratory behavioral tools that are parallel in their parameters in rodents and humans, the neuromechanisms underlying behaviors with relevance to these symptoms of schizophrenia can be investigated. We describe tasks that measure the motivation of rodents to expend physical and cognitive effort to gain rewards, as well as probabilistic learning tasks that assess both reward learning and feedback-based decision making. The latter tasks are relevant because of demonstrated links of performance deficits correlating with negative symptoms in patients with schizophrenia. These tasks utilize operant techniques in order to investigate neural circuits targeting a specific domain across species. These tasks therefore enable the development of insights into altered mechanisms leading to negative symptom-relevant behaviors in patients with schizophrenia. Such findings will then enable the development of targeted treatments for these altered neuromechanisms and behaviors seen in schizophrenia. PMID:26194891

  20. Thermochemical analysis of chemical processes relevant to the stability and processing of SiC-reinforced Si3N4 composite

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1991-01-01

    Chemical processes relevant to the stability and processing of SiC-reinforced Si3N4 composites have been examined from thermochemical considerations. The thermodynamic stabilities of various interfaces, such as SiC-Si3N4, SiC-Si3N4-Si2ON2, and SiC-Si3N4-SiO2, have been examined as a function of temperature, and the temperatures above which these interfaces become unstable have been calculated. The degradation of SiC during the processing of the composite has been examined. The processing routes considered in this study include the reaction bonded silicon nitride (RBSN) process and the pressure-assisted sintering processes with suitable sintering additives.

  1. Transport phenomena relevant to the impact regime of the process of spray deposition: A review. Part 1: Heat transfer

    SciTech Connect

    Poulikakos, D.; Waldvogel, J.M.

    1995-12-31

    Spray deposition is a novel rapid solidification technology for the creation of advanced metals and metal composites. This technology is particularly attractive to manufacturing because it shows promise to provide materials and products that combine superior properties and near net shape. With reference to the former, the extremely high cooling rates present in the process of spray deposition capture non equilibrium states that cannot be captured by more conventional casting methods because the atomic mobility in the liquid phase of a metal is far greater than that in the solid phase. To this end, the cooling rates at the early stages of the spray deposition process are of the order of (10{sup 6} to 10{sup 8}) {sup 0}C/s. With reference to the latter, the spray deposition process has been shown to produce near net shape products which eliminates the need for additional finishing steps in the manufacturing process. Moreover, the fine and homogeneous microstructure that appears to be resulting from the spray deposition process may eliminate the need for additional mechanical working. In this, as well as its companion paper appearing subsequently in this volume, a review is presented of the existing knowledge base of the impact regime of the process of spray deposition, focusing on issues in which transport phenomena are relevant. Further, this paper addresses only heat transfer aspects of the process which do not involve sophisticated modeling of the accompanying complex fluid dynamics.

  2. Theoretical and Practical Issues That Are Relevant When Scaling Up hMSC Microcarrier Production Processes.

    PubMed

    Jossen, Valentin; Schirmer, Cedric; Mostafa Sindi, Dolman; Eibl, Regine; Kraume, Matthias; Pörtner, Ralf; Eibl, Dieter

    2016-01-01

    The potential of human mesenchymal stem cells (hMSCs) for allogeneic cell therapies has created a large amount of interest. However, this presupposes the availability of efficient scale-up procedures. Promising results have been reported for stirred bioreactors that operate with microcarriers. Recent publications focusing on microcarrier-based stirred bioreactors have demonstrated the successful use of Computational Fluid Dynamics (CFD) and suspension criteria (N S1u , N S1) for rapidly scaling up hMSC expansions from mL- to pilot scale. Nevertheless, one obstacle may be the formation of large microcarrier-cell-aggregates, which may result in mass transfer limitations and inhomogeneous distributions of stem cells in the culture broth. The dependence of microcarrier-cell-aggregate formation on impeller speed and shear stress levels was investigated for human adipose derived stromal/stem cells (hASCs) at the spinner scale by recording the Sauter mean diameter (d 32) versus time. Cultivation at the suspension criteria provided d 32 values between 0.2 and 0.7 mm, the highest cell densities (1.25 × 10(6) cells mL(-1) hASCs), and the highest expansion factors (117.0 ± 4.7 on day 7), while maintaining the expression of specific surface markers. Furthermore, suitability of the suspension criterion N S1u was investigated for scaling up microcarrier-based processes in wave-mixed bioreactors for the first time. PMID:26981131

  3. Theory and High-Energy-Density Laser Experiments Relevant to Accretion Processes in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Krauland, Christine; Drake, R.; Loupias, B.; Falize, E.; Busschaert, C.; Ravasio, A.; Yurchak, R.; Pelka, A.; Koenig, M.; Kuranz, C. C.; Plewa, T.; Huntington, C. M.; Kaczala, D. N.; Klein, S.; Sweeney, R.; Villete, B.; Young, R.; Keiter, P. A.

    2012-05-01

    We present results from high-energy-density (HED) laboratory experiments that explore the contribution of radiative shock waves to the evolving dynamics of the cataclysmic variable (CV) systems in which they reside. CVs can be classified under two main categories, non-magnetic and magnetic. In the process of accretion, both types involve strongly radiating shocks that provide the main source of radiation in the binary systems. This radiation can cause varying structure to develop depending on the optical properties of the material on either side of the shock. The ability of high-intensity lasers to create large energy densities in targets of millimeter-scale volume makes it feasible to create similar radiative shocks in the laboratory. We provide an overview of both CV systems and their connection to the designed and executed laboratory experiments preformed on two laser facilities. Available data and accompanying simulations will likewise be shown. Funded by the NNSA-DS and SC-OFES Joint Prog. in High-Energy-Density Lab. Plasmas, by the Nat. Laser User Facility Prog. in NNSA-DS and by the Predictive Sci. Acad. Alliances Prog. in NNSA-ASC, under grant numbers are DE-FG52-09NA29548, DE-FG52-09NA29034, and DE-FC52-08NA28616.

  4. Effects of intranasal oxytocin on neural processing within a socially relevant neural circuit.

    PubMed

    Singh, Fiza; Nunag, Jason; Muldoon, Glennis; Cadenhead, Kristin S; Pineda, Jaime A; Feifel, David

    2016-03-01

    Dysregulation of the Mirror Neuron System (MNS) in schizophrenia (SCZ) may underlie the cognitive and behavioral manifestations of social dysfunction associated with that disorder. In healthy subjects intranasal (IN) oxytocin (OT) improves neural processing in the MNS and is associated with improved social cognition. OT's brain effects can be measured through its modulation of the MNS by suppressing EEG mu-band electrical activity (8-13Hz) in response to motion perception. Although IN OT's effects on social cognition have been tested in SCZ, OT's impact on the MNS has not been evaluated to date. Therefore, we designed a study to investigate the effects of two different OT doses on biological motion-induced mu suppression in SCZ and healthy subjects. EEG recordings were taken after each subject received a single IN administration of placebo, OT-24IU and OT-48IU in randomized order in a double-blind crossover design. The results provide support for OT's regulation of the MNS in both healthy and SCZ subjects, with the optimal dose dependent on diagnostic group and sex of subject. A statistically significant response was seen in SCZ males only, indicating a heightened sensitivity to those effects, although sex hormone related effects cannot be ruled out. In general, OT appears to have positive effects on neural circuitry that supports social cognition and socially adaptive behaviors. PMID:26727038

  5. Theoretical and Practical Issues That Are Relevant When Scaling Up hMSC Microcarrier Production Processes

    PubMed Central

    Jossen, Valentin; Schirmer, Cedric; Mostafa Sindi, Dolman; Eibl, Regine; Kraume, Matthias; Pörtner, Ralf; Eibl, Dieter

    2016-01-01

    The potential of human mesenchymal stem cells (hMSCs) for allogeneic cell therapies has created a large amount of interest. However, this presupposes the availability of efficient scale-up procedures. Promising results have been reported for stirred bioreactors that operate with microcarriers. Recent publications focusing on microcarrier-based stirred bioreactors have demonstrated the successful use of Computational Fluid Dynamics (CFD) and suspension criteria (NS1u, NS1) for rapidly scaling up hMSC expansions from mL- to pilot scale. Nevertheless, one obstacle may be the formation of large microcarrier-cell-aggregates, which may result in mass transfer limitations and inhomogeneous distributions of stem cells in the culture broth. The dependence of microcarrier-cell-aggregate formation on impeller speed and shear stress levels was investigated for human adipose derived stromal/stem cells (hASCs) at the spinner scale by recording the Sauter mean diameter (d32) versus time. Cultivation at the suspension criteria provided d32 values between 0.2 and 0.7 mm, the highest cell densities (1.25 × 106 cells mL−1 hASCs), and the highest expansion factors (117.0 ± 4.7 on day 7), while maintaining the expression of specific surface markers. Furthermore, suitability of the suspension criterion NS1u was investigated for scaling up microcarrier-based processes in wave-mixed bioreactors for the first time. PMID:26981131

  6. A review of abiotic and biotic interactions in pelagic communities: Processes relevant to L Lake

    SciTech Connect

    Bowers, J.A.

    1988-01-01

    The purpose of this report is to provide a state-of-the-art review of structural and functional processes in pelagic communities and extrapolate these empirical and theoretical results to L Lake, the once-through cooling reservoir at the Savannah River Plant. Man-made reservoirs differ from natural lakes in their origins, hydrodynamics, sedimentation patterns, and general eutrophication histories. Phosphorus and nitrogen limitation of phytoplankton productivity controls the rate of eutrophication, while also determining algal community structure. Here the Lean and Monod models of nutrient fluxing and uptake kinetics provide useful constructs for predictive purposes. Much of the reduced carbon synthesized by primary production is shunted through the microbial loop where heterotrophic flagellates and protozoans pass this carbon on to the macrozooplankton. This recently discovered pathway is common to eutrophic reservoirs where blue-green species dominate phytoplankton assemblages. Through selective grazing and tactile oriented predation, the crustacean zooplankton partially regulates the relative abundance of algae and microzooplankton species. 194 refs., 10 figs.

  7. Electron Irradiation and Thermal Processing of Mixed-ices of Potential Relevance to Jupiter Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Mahjoub, Ahmed; Poston, Michael J.; Hand, Kevin P.; Brown, Michael E.; Hodyss, Robert; Blacksberg, Jordana; Eiler, John M.; Carlson, Robert W.; Ehlmann, Bethany L.; Choukroun, Mathieu

    2016-04-01

    In this work we explore the chemistry that occurs during the irradiation of ice mixtures on planetary surfaces, with the goal of linking the presence of specific chemical compounds to their formation locations in the solar system and subsequent processing by later migration inward. We focus on the outer solar system and the chemical differences for ice mixtures inside and outside the stability line for H2S. We perform a set of experiments to explore the hypothesis advanced by Wong & Brown that links the color bimodality in Jupiter's Trojans to the presence of H2S in the surface of their precursors. Non-thermal (10 keV electron irradiation) and thermally driven chemistry of CH3OH-NH3-H2O (“without H2S”) and H2S-CH3OH-NH3-H2O (“with H2S”) ices were examined. Mid-IR analyses of ice and mass spectrometry monitoring of the volatiles released during heating show a rich chemistry in both of the ice mixtures. The “with H2S” mixture experiment shows a rapid consumption of H2S molecules and production of OCS molecules after a few hours of irradiation. The heating of the irradiated “with H2S” mixture to temperatures above 120 K leads to the appearance of new infrared bands that we provisionally assign to SO2and CS. We show that radiolysis products are stable under the temperature and irradiation conditions of Jupiter Trojan asteroids. This makes them suitable target molecules for potential future missions as well as telescope observations with a high signal-to-noise ratio. We also suggest the consideration of sulfur chemistry in the theoretical modeling aimed at understanding the chemical composition of Trojans and KOBs.

  8. Radiative Reverse Shock Laser Experiments Relevant to Accretion Processes in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Krauland, Christine

    2012-10-01

    We present results from experiments that explore radiative reverse shock waves and their contribution to the evolving dynamics of the cataclysmic variable (CV) system in which they reside. CVs are close binary star systems containing a white dwarf (WD) that accretes matter from its late-type main sequence companion star. In the process of accretion, a reverse shock forms when the supersonic infalling plasma is impeded. It provides the main source of radiation in the binary systems. In the case of a non-magnetic CV, the impact on an accretion disk produces this ``hot spot,'' where the flow obliquely strikes the rotating accretion disk. This collision region has many ambiguities as a radiation hydrodynamic system, but shock development in the infalling flow can be modeled [1]. We discuss the production of radiative reverse shocks in experiments at the Omega-60 laser facility. The ability of this high-intensity laser to create large energy densities in targets having millimeter-scale volumes makes it feasible to create supersonic plasma flows. Obtaining a radiative reverse shock in the laboratory requires a sufficiently fast flow (> 60 km/s) within a material whose opacity is large enough to produce energetically significant emission from experimentally achievable layers. We will show the radiographic and emission data from three campaigns on Omega-60 with accompanying CRASH [2] simulations, and will discuss the implications in the context of the CV system. [4pt] [1] Armitage, P. J. and Livio, M., ApJ, 493, 898 (1998).[0pt] [2] van der Holst, B., Toth, G., Sokolov, I.V., et al., ApJS, 194, 23 (2011).

  9. Numerical Investigations of Photoevaporative Disks: Processes relevant to planet and regular satellite formation

    NASA Astrophysics Data System (ADS)

    Mitchell, Tyler Robert

    Traditional models of disks around young planets and stars make a number of simplifying assumptions. These include the use of ad hoc radial temperature profiles, or isothermal disks. Another common assumption is in regard to the treatment of the outer boundary, which is allowed to expand to infinity, or neglected completely. There has also been a lack of time-dependent viscous models that include the affects of photoevaporation and/or ongoing accretion. We alleviate many of these issues by adapting numerical methods for solving propagating phase change problems to astrophysical disks in a completely novel way. These models are all viscous, time-dependent models that include a self-consistent treatment of mass loss via photoevaporation at the disk outer edge. In the case of circumplanetary disks, they also include continued accretion from the solar nebula. I present investigations of disks around young planets and stars, made using a variety of numerical models. The investigations are primarily focused on how disk structure and evolution affect the growth and migration of growing satellite and planetary embryos. Another focus is to assess what, if any, processes are responsible for angular momentum transport in circumplanetary disks. I present detailed descriptions of these models as well as the results of applying these models to both the solar nebula and to disks around giant planets, in which regular satellites formed. Photoevaporation can substantially truncate disks and has a similar level of affect on disk evolution and morphology as variations in the viscosity parameter, alpha All of the solar nebula models were truncated, yet none of them match the steep radial surface density profile inferred from the compact configuration of the giant planets in the Nice model. Furthermore, photoevaporation has the ability to remove gas and dissipate disks on very short timescales. Despite their evolving nature, we find that giant planets and satellites can form in the

  10. Pristine Igneous Rocks and the Genesis of Early Planetary Crusts

    NASA Technical Reports Server (NTRS)

    Warren, Paul H.; Lindstrom, David (Technical Monitor)

    2002-01-01

    Our studies are highly interdisciplinary, but are focused on the processes and products of early planetary and asteroidal differentiation, especially the genesis of the ancient lunar crust. The compositional diversity that we explore is the residue of process diversity, which has strong relevance for comparative planetology.

  11. Ca Isotopic Ratios in Igneous Rocks: Some Preliminary Results

    NASA Astrophysics Data System (ADS)

    Huang, S.; Farkas, J.; Jacobsen, S. B.

    2009-12-01

    Calcium (Ca) is the 5th most abundant element on the Earth, and it is an important geochemical and cosmochemical tracer. It has six isotopes and only H and He have a larger percentage mass difference (Δm/m) between the heaviest and the lightest isotopes. Systematic Ca isotopic studies have mostly focused on low-temperature geochemical processes, and most Ca isotopic analyses have been applied on modern and ancient marine carbonates and sulphates, documenting large and systematic isotopic variations, which were used to infer the chemical evolution of seawater. Detailed work on igneous rocks is very limited. Here we show two examples of how stable Ca isotopic ratios can be a useful geochemical tool in understanding igneous processes. Ca isotopic fractionation between coexisting clinopyroxene and orthopyroxene from mantle peridotites: We report Ca isotopic ratios on co-existing clino- and ortho-pyroxenes from Kilbourne Hole and San Carlos mantle peridotites. The 44Ca/40Ca in orthopyroxenes is ~0.5 per mil heavier than that in co-existing clinopyroxenes. Combined with published Ca isotopic data on low-temperature Ca-bearing minerals (calcite, aragonite and barite), we show that the fractionation of Ca isotopes between Ca-bearing minerals (at both low-temperature and high-temperature) is primarily controlled by the strength of Ca-O bond in the minerals. The mineral with shorter (i.e., stronger) Ca-O bond yields heavier Ca isotopic ratio. Using our measured 44Ca/40Ca in mantle pyroxenes and the relative proportions of major Ca-bearing minerals in the upper mantle, the estimated 44Ca/40Ca of the upper mantle is 1.1 per mil heavier relative to the NIST 915a, ~0.1 to 0.2 per mil higher than basalts. Ca isotopic variation in Hawaiian shield lavas: Large geochemical and isotopic variations have been observed in lavas forming the large tholeiitic shields of Hawaiian volcanoes, with lavas from the surface of the Koolau volcano (Makapuu-stage) defining one compositional and

  12. Integrating isotopic fingerprinting with petrology: how do igneous rocks evolve?

    NASA Astrophysics Data System (ADS)

    Davidson, J. P.

    2002-12-01

    In the title of his seminal work, N.L. Bowen recognized the fundamental importance of magmatic evolution in producing the spectrum of igneous rocks. Indeed it is difficult to imagine a hot highly reactive fluid passing through c. 100 km of a chemically distinct medium (lithosphere) without evolving through cooling, crystallization and interaction with the wall rocks. The fact that magmas evolve - almost invariably through open system processes - has been largely marginalized in the past 30 years by the desire to use them as probes of mantle source regions. This perspective has been driven principally by advances offered by isotope geochemistry, through which components and sources can be effectively fingerprinted. Two fundamental observations urge caution in ignoring differentiation effects; 1) the scarcity of truly primary magmas according to geochemical criteria (recognized long ago by petrologists), and 2) the common occurrence of petrographic criteria attesting to open system evolution. Recent advances in multicollector mass spectrometry permit integration of the powerful diagnostic tools of isotope geochemistry with petrographic observations through accurate and precise analysis of small samples. Laser ablation and microdrilling enable sampling within and between mineral phases. The results of our microsampling investigations give widespread support for open system evolution of magmas, and provide insights into the mechanisms and timescales over which this occurs. For example; 1) core-rim decreases in 87Sr/86Sr in zoned plagioclase crystals from 1982 lavas of El Chichon volcano, Mexico, argue that the zoning and isotopic changes are in response to magma recharge mixing with an originally contaminated resident magma; 2) Single grain and intra-grain isotopic analyses of mineral phases from Ngauruhoe andesites (New Zealand) are highly variable, arguing that bulk rock data reflect mechanical aggregations of components which have evolved in discrete domains of the

  13. Large Silica-Rich Igneous-Textured Inclusions in the Buzzard Coulee (H4) Chondrite

    NASA Astrophysics Data System (ADS)

    Ruzicka, A.; Hutson, M.; Floss, C.; Hildebrand, A.

    2012-03-01

    Buzzard Coulee (H4) contains two types of large, igneous inclusions that are best explained by igneous differentiation, but which also show evidence for cooling and vapor phase phenomena consistent with transit through a space environment.

  14. Igneous fractionation and subsolidus equilibration of diogenite meteorites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.

    1993-01-01

    Diogenites are coarse-grained orthopyroxenite breccias of remarkably uniform major element composition. Most diogenites contain homogeneous pyroxene fragments up to 5 cm across of Wo2En74Fs24 composition. Common minor constituents are chromite, olivine, trolite and metal, while silica, plagioclase, merrillite and diopside are trace phases. Diogenites are generally believed to be cumulates from the eucrite parent body, although their relationship with eucrites remains obscure. It has been suggested that some diogenites are residues after partial melting. I have performed EMPA and INAA for major, minor and trace elements on most diogenites, concentrating on coarse-grained mineral and lithic clasts in order to elucidate their igneous formation and subsequent metamorphic history. Major element compositions of diogenites are decoupled from minor and trace element compositions; the latter record an igneous fractionation sequence that is not preserved in the former. Low equilibration temperatures indicate that major element diffusion continued long after crystallization. Diffusion coefficients for trivalent and tetravalent elements in pyroxene are lower than those of divalent elements. Therefore, major element compositions of diogenites may represent means of unknown portions of a cumulate homogenized by diffusion, while minor and trace elements still yield information on their igneous history. The scale of major element equilibration is unknown, but is likely to be on the order of a few cm. Therefore, the diogenite precursors may have consisted largely of cm-sized, igneously zoned orthopyroxene grains, which were subsequently annealed during slow cooling, obliterating major element zoning but preserving minor and trace incompatible element zoning.

  15. The Formation of Igneous CAIs and Chondrules by Impacts?

    NASA Technical Reports Server (NTRS)

    Connolly, Harold C., Jr.; Love, Stanley G.

    2001-01-01

    Numerous challenges exist with forming the igneous spheres found within chondrites via collision events in the early solar nebula. We explore these challenges and discuss potential methods to overcome them. Collision models should be received cautiously. Additional information is contained in the original extended abstract.

  16. Culturally relevant family-based treatment for adolescent delinquency and substance abuse: understanding within-session processes.

    PubMed

    Cunningham, Phillippe B; Foster, Sharon L; Warner, Sarah E

    2010-08-01

    Identifying psychotherapy processes that likely contribute to client outcome with ethnic minorities is a vital practice and research need, particularly within family-focused, evidence-based treatments (EBT) for youth with externalizing problems. Identifying process variables within a cross-cultural context may improve the efficacy of EBTs by informing psychotherapists how to modify their behavior when working with ethnically diverse clients. The authors described one approach to the development of culturally competent psychotherapy, using an observational coding system comprising Afrocentric codes to investigate culturally relevant therapist behaviors. Qualitative examples illustrated the quantitative findings relating to therapist in-session behavior that promote client engagement and positive responding during a midtreatment session of multisystemic therapy. PMID:20564683

  17. Potentially clinically relevant prostate cancer is found more frequently after complete than after partial histopathological processing of radical cystoprostatectomy specimens.

    PubMed

    Fritsche, H M; Aziz, A; Eder, F; Otto, W; Denzinger, S; Wieland, W F; May, M; Hofstädter, F; Hartmann, A; Burger, M

    2012-12-01

    Incidental prostate cancer is often found in cystoprostatectomy specimens. The presence of a clinically significant tumour has an impact on follow-up strategies. In prostatectomy specimen for prostate cancer, whole-mount sections improve diagnostic accuracy. The present study compares detection of incidental prostate cancer in complete to routine processing. We included 295 consecutive patients who underwent radical cystoprostatectomy. Between 01/1995 and 12/2003 (period I), specimens of 129 patients were partially processed, whereas between 01/2004 and 03/2009 (period II), specimens of 166 patients were completely processed. Incidental prostate cancer was detected overall in 91 (30.8 %) patients. Prostate cancer was detected in 24 (18.6 %) patients in period 1 and in 67 (40.4 %) patients in period 2 (p < 0.001). Potentially clinically significant prostate cancer was detected in 12 (9.2 %) and 29 (17.5 %) patients, respectively (p = 0.044). Complete embedding and processing of cystoprostatectomy specimen yield significantly more potentially clinically relevant prostate cancers. The present data suggest that notably in younger men the specimens should be completely processed. PMID:23052374

  18. Thermal, High Pressure, and Electric Field Processing Effects on Plant Cell Membrane Integrity and Relevance to Fruit and Vegetable Quality

    PubMed Central

    Gonzalez, Maria E; Barrett, Diane M

    2010-01-01

    Advanced food processing methods that accomplish inactivation of microorganisms but minimize adverse thermal exposure are of great interest to the food industry. High pressure (HP) and pulsed electric field (PEF) processing are commercially applied to produce high quality fruit and vegetable products in the United States, Europe, and Japan. Both microbial and plant cell membranes are significantly altered following exposure to heat, HP, or PEF. Our research group sought to quantify the degree of damage to plant cell membranes that occurs as a result of exposure to heat, HP, or PEF, using the same analytical methods. In order to evaluate whether new advanced processing methods are superior to traditional thermal processing methods, it is necessary to compare them. In this review, we describe the existing state of knowledge related to effects of heat, HP, and PEF on both microbial and plant cells. The importance and relevance of compartmentalization in plant cells as it relates to fruit and vegetable quality is described and various methods for quantification of plant cell membrane integrity are discussed. These include electrolyte leakage, cell viability, and proton nuclear magnetic resonance (1H-NMR). PMID:20492210

  19. Did North Atlantic Igneous Province igneous sills trigger or maintain Paleocene Eocene Thermal Maximum global warming?

    NASA Astrophysics Data System (ADS)

    Fernandes, Karina; Jones, Stephen M.; Schofield, Nick; Clayton, Geoff

    2010-05-01

    Igneous sills of the North Atlantic Igneous Province (NAIP) were intruded into organic-rich sediments, generating methane and carbon dioxide by thermal maturation. These greenhouse gases escaped to the ocean and atmosphere through hydrothermal vents above the sills that have been observed on seismic reflection data and by drilling. It has been suggested that the NAIP sills provided a significant component of the greenhouse gases that forced warming during the Paleocene Eocene Thermal Maximum (PETM). Here we consider whether methane released by NAIP sills could have triggered, as well as maintained, the PETM warming. Warming resulting from the PETM trigger began a few thousand years before the major upheaval in the carbon cycle that was associated with the PETM itself. Recent organic geochemical investigations have suggested that methane was involved in the trigger. Since the lifetime of methane in the atmosphere was approximately one decade during the Paleocene, the triggering methane pulse probably contained on the order of 100 Gt or more of carbon and was probably released in a period of c. 10 years or less. We use recent field observations of fluidized country rocks around sills to speculate on a model for sill emplacement, greenhouse gas generation and escape. The observation of fluidized sediments associated with lobe and finger structures along inward-dipping sections of many sills suggests that these sill rims propagated laterally by fluidizing a restricted volume of country rock, allowing the magma to advance into the fluidized region as a viscous fingering front. At this stage, the fluidized region was not connected to the surface by a conduit, so greenhouse gases could not escape rapidly. Eventually, as the sill rim propagated laterally and upward, a hydrothermal conduit was initiated and propagated rapidly upward to the surface. This model, based on field observations implies that the gases which initially escaped up the hydrothermal conduit were

  20. The Kenna ureilite - An ultramafic rock with evidence for igneous, metamorphic, and shock origin

    NASA Technical Reports Server (NTRS)

    Berkley, J. L.; Brown, H. G.; Keil, K.; Carter, N. L.; Mercier, J.-C. C.; Huss, G.

    1976-01-01

    Ureilites are a rare group of achondrites. They are composed mainly of olivine and pigeonite in a matrix of carbonaceous material, including graphite, lonsdaleite, diamond, and metal. In most respects Kenna is a typical ureilite with the requisite mineralogical and chemical properties of the group. Differences of the Kenna ureilite from previously studied ureilites are related to a greater density, the occurrence of exceedingly minute quantities of feldspar, and a very strong elongation lineation of the silicate minerals. A description is presented of a study which indicates a complex history for Kenna, including igneous, mild metamorphic, and shock processes.

  1. Petrology of the Betulia Igneous Complex, Cauca, Colombia

    NASA Astrophysics Data System (ADS)

    Gil-Rodriguez, Javier

    2014-12-01

    The Betulia Igneous Complex (BIC) is a group of Late-Miocene (11.8 ± 0.2 Ma) hypabyssal intrusions of intermediate to felsic composition located in the SW of the Colombian Andes. These bodies have a calc-alkaline tendency and are related to the subduction of the Nazca plate under the South American plate. Diorites, quartz diorites and tonalities have porphyritic and phaneritic textures and are composed of plagioclase, amphibole, quartz, biotite, and orthoclase. Plagioclase is mainly of andesine-type and the amphiboles were classified mainly as magnesiohornblendes, actinolites, and tschermakites. BIC rocks have a narrow range of SiO2 content (59-67wt%) and exhibit an enrichment of LILE and LREE relative to HFSE and HREE, respectively. These features are attributed to enrichment of LILE from the source and retention of HFSE (mainly Nb, Ta, and Ti) by refractory phases within the same source. The depletion of HREE is explained by fractionation of mineral phases that have a high partition coefficients for these elements, especially amphiboles, the major mafic phase in the rocks. Nevertheless, the fractionation of garnet in early stages of crystallization is not unlikely. Probably all BIC units were generated by the same magma chamber or at least by the same petrologic mechanism as shown by the similar patterns in spider and REE diagrams; fractional crystallization and differentiation processes controlled the final composition of the rocks, and crystallization stages determined the texture. Isotopic compositions of BIC rocks (87Sr/86Sr: 0.70435-0.70511; 143Nd/144Nd: 0.51258-0.51280; 206Pb/204Pb: 19.13-19.31; 207Pb/204Pb: 15.67-15.76; 208Pb/204Pb: 38.93-39.20) indicate a source derived from the mantle with crustal contamination. The model proposed for the BIC consists of fluids from the dehydration of the subducted slab (Nazca plate) and subducted sediments that generated partial melting of the mantle wedge. These basaltic melts ascended to the mantle-crust boundary

  2. Protease recognition sites in Bet v 1a are cryptic, explaining its slow processing relevant to its allergenicity

    PubMed Central

    Freier, Regina; Dall, Elfriede; Brandstetter, Hans

    2015-01-01

    Despite a high similarity with homologous protein families, only few proteins trigger an allergic immune response with characteristic TH2 polarization. This puzzling observation is illustrated by the major birch pollen allergen Bet v 1a and its hypoallergenic protein isoforms, e.g., Bet v 1d. Given the key role of proteolytic processing in antigen presentation and T cell polarization, we investigated the recognition of Bet v 1 isoforms by the relevant protease cathepsin S. We found that at moderately acidic pH values Bet v 1a bound to cathepsin S with significantly lower affinity and was more slowly cleaved than its hypoallergenic isoform Bet v 1d. Only at pH values ≤4.5 the known proteolytic cleavage sites in Bet v 1a became accessible, resulting in a strong increase in affinity towards cathepsin S. Antigen processing and class II MHC loading occurs at moderately acidic compartments where processing of Bet v 1a and Bet v 1d differs distinctly. This difference translates into low and high density class II MHC loading and subsequently in TH2 and TH1 polarization, respectively. PMID:26235974

  3. Lunar igneous rocks and the nature of the lunar interior

    NASA Technical Reports Server (NTRS)

    Hays, J. F.; Walker, D.

    1977-01-01

    Lunar igneous rocks, properly interpreted, can give useful information about mineral assemblages and mineral chemistry as a function of depth in the lunar interior. Though intensely brecciated, terra rocks reveal, in their chemistry, evidence for a magmatic history. Partial melting of feldspathic lunar crustal material occurred in the interval 4.6 to 3.9 Gy. Melting of ilmenite-bearing cumulates at depths near 100 km produced parent magmas for Apollo 11 and 17 titaniferous mare basalts in the interval 3.8 to 3.6 Gy. Melting of ilmenite-free olivine pyroxenites (also cumulates?) at depths greater than 200 km produced low-titanium mare basalts in the interval 3.4 to 3.1 Gy. No younger igneous rocks have yet been recognized among the lunar samples and present-day melting seems to be limited to depths greater than 1000 km.

  4. Lunar igneous rocks and the nature of the lunar interior

    NASA Technical Reports Server (NTRS)

    Hays, J. F.; Walker, D.

    1974-01-01

    Lunar igneous rocks are interpreted, which can give useful information about mineral assemblages and mineral chemistry as a function of depth in the lunar interior. Terra rocks, though intensely brecciated, reveal, in their chemistry, evidence for a magmatic history. Partial melting of feldspathic lunar crustal material occurred in the interval 4.6 to 3.9 gy. Melting of ilmenite-bearing cumulates at depths near 100 km produced parent magmas for Apollo 11 and 17 titaniferous mare basalts in the interval 3.8 to 3.6 gy. Melting of ilmenite-free olivine pyroxenites at depths greater than 200 km produced low-titanium mare basalts in the interval 3.4 to 3.1 gy. No younger igneous rocks have yet been recognized among the lunar samples and present-day melting seems to be limited to depths greater than 1000 km.

  5. Kinetics of the Reduction of Hematite Concentrate Particles by Carbon Monoxide Relevant to a Novel Flash Ironmaking Process

    NASA Astrophysics Data System (ADS)

    Chen, Feng; Mohassab, Yousef; Zhang, Shengqin; Sohn, Hong Yong

    2015-08-01

    A novel ironmaking process is under development at the University of Utah to produce iron directly from iron oxides concentrates by the gas-solid flash reaction using gaseous fuels and reductants. This process will reduce energy consumption and minimize carbon dioxide emissions. Having investigated the hydrogen reduction kinetics of magnetite and hematite concentrate particles relevant to the novel flash ironmaking process, the carbon monoxide reduction kinetics of hematite concentrate particles (average particle size 21 µm) was determined in the temperature range 1473 K to 1623 K (1200 °C to 1350 °C) under various carbon monoxide partial pressures. At 1623 K (1350 °C) and residence time 5 seconds, the reduction degree of hematite concentrate particles was more than 90 pct under a pure carbon monoxide. This is slower than reduction by hydrogen but still significant, indicating that CO will contribute to the reduction of hematite concentrate in the flash process. The kinetics of CO reduction separately from hydrogen is important for understanding and analyzing the complex kinetics of hematite reduction by the H2 + CO mixtures. The nucleation and growth rate equation with the Avrami parameter n = 1.0 adequately described the carbon monoxide reduction kinetics of hematite concentrate particles. The reduction rate is of 1st order with respect to the partial pressure of carbon monoxide and the activation energy of the reaction was 231 kJ/mol, indicating strong temperature dependence. The following complete rate equation was developed that can satisfactorily predict the carbon monoxide reduction kinetics of hematite concentrate particles and is suitable for the design of a flash reactor where X is the fraction of oxygen removed from iron oxide, R is 8.314 J/mol K, T is in K, p is in atm, and t is in seconds.

  6. Log evaluation of oil-bearing igneous rocks

    SciTech Connect

    Khatchikian, A.

    1983-12-01

    The evaluation of porosity, water saturation and clay content of oilbearing igneous rocks with well logs is difficult due to the mineralogical complexity of this type of rocks. The log responses to rhyolite and rhyolite tuff; andesite, dacite and zeolite tuff; diabase and basalt have been studied from examples in western Argentina and compared with values observed in other countries. Several field examples show how these log responses can be used in a complex lithology program to make a complete evaluation.

  7. Dielectric properties of pharmaceutical materials relevant to microwave processing: effects of field frequency, material density, and moisture content.

    PubMed

    Heng, Paul W S; Loh, Z H; Liew, Celine V; Lee, C C

    2010-02-01

    The rising popularity of microwaves for drying, material processing and quality sensing has fuelled the need for knowledge concerning dielectric properties of common pharmaceutical materials. This article represents one of the few reports on the density and moisture content dependence of the dielectric properties of primary pharmaceutical materials and their relevance to microwave-assisted processing. Dielectric constants (epsilon') and losses (epsilon'') of 13 pharmaceutical materials were measured over a frequency range of 1 MHz-1 GHz at 23 +/- 1 degrees C using a parallel-electrode measurement system. Effects of field frequency, material density and moisture content on dielectric properties were studied. Material dielectric properties varied considerably with frequency. At microwave frequencies, linear relationships were established between cube-root functions of the dielectric parameters [symbols: see text] and density which enabled dielectric properties of materials at various densities to be estimated by regression. Moisture content was the main factor that contributed to the disparities in dielectric properties and heating capabilities of the materials in a laboratory microwave oven. The effectiveness of a single frequency density-independent dielectric function for moisture sensing applications was explored and found to be suitable within low ranges of moisture contents for a model material. PMID:19708060

  8. Biological Production of a Hydrocarbon Fuel Intermediate Polyhydroxybutyrate (PHB) from a Process Relevant Lignocellulosic Derived Sugar (Poster)

    SciTech Connect

    Wang, W.; Mittal, A.; Mohagheghi, A.; Johnson, D. K.

    2014-04-01

    PHAs are synthesized by many microorganisms to serve as intracellular carbon storage molecules. In some bacterial strains, PHB can account for up to 80% of cell mass. In addition to its application in the packaging sector, PHB also has great potential as an intermediate in the production of hydrocarbon fuels. PHB can be thermally depolymerized and decarboxylated to propene which can be upgraded to hydrocarbon fuels via commercial oligomerization technologies. Cupriavidus necator is the microorganism that has been most extensively studied and used for PHB production on an industrial scale; However the substrates used for producing PHB are mainly fructose, glucose, sucrose, fatty acids, glycerol, etc., which are expensive. In this study, we demonstrate production of PHB from a process relevant lignocellulosic derived sugar stream, i.e., saccharified slurry from pretreated corn stover. The strain was first investigated in shake flasks for its ability to utilize glucose, xylose and acetate. In addition, the strain was also grown on pretreated lignocellulose hydrolyzate slurry and evaluated in terms of cell growth, sugar utilization, PHB accumulation, etc. The mechanism of inhibition in the toxic hydrolysate generated by the pretreatment and saccharification process of biomass, was also studied.

  9. On the Formation of Amide Polymers via Carbonyl-Amino Group Linkages in Energetically Processed Ices of Astrophysical Relevance

    NASA Astrophysics Data System (ADS)

    Förstel, Marko; Maksyutenko, Pavlo; Jones, Brant M.; Sun, Bing J.; Lee, Huan C.; Chang, Agnes H. H.; Kaiser, Ralf I.

    2016-04-01

    We report on the formation of organic amide polymers via carbonyl-amino group linkages in carbon monoxide and ammonia bearing energetically processed ices of astrophysical relevance. The first group comprises molecules with one carboxyl group and an increasing number of amine moieties starting with formamide (45 u), urea (60 u), and hydrazine carboxamide (75 u). The second group consists of species with two carboxyl (58 u) and up to three amine groups (73 u, 88 u, and 103 u). The formation and polymerization of these linkages from simple inorganic molecules via formamide und urea toward amide polymers is discussed in an astrophysical and astrobiological context. Our results show that long chain molecules, which are closely related to polypeptides, easily form by energetically processing simple, inorganic ices at very low temperatures and can be released into the gas phase by sublimation of the ices in star-forming regions. Our experimental results were obtained by employing reflectron time-of-flight mass spectroscopy, coupled with soft, single photon vacuum ultraviolet photoionization; they are complemented by theoretical calculations.

  10. Crustal architecture of a continental large igneous province

    NASA Astrophysics Data System (ADS)

    Minakov, Alexander; Faleide, Jan Inge; Krupnova, Natalia; Sakoulina, Tamara

    2014-05-01

    The northern Barents Sea was strongly affected by the Cretaceous High Arctic Large Igneous Province through abundant mafic intrusions, eruption of flood basalts, and regional uplift. Recently acquired geophysical data in this region provide a unique opportunity to study in detail crustal architecture of large igneous provinces. A giant dike swarm is identified based on magnetic anomalies coherent over a distance of hundreds of kilometers. Coincident ocean bottom seismometer, multichannel streamer, and gravity data indicate that the surface basalts and shallow sills were associated with feeder systems cross-cutting the entire crust. At the same time, the distribution of dikes exhibits more complex pattern than radially symmetric with respect to the presumable magmatic center in the Alpha Ridge region. Thus, the preferred orientation of dikes could be controlled by both paleostress and pre-existing weaknesses (Early-Late Paleozoic faults). The data do not indicate a thick igneous mafic lower crust while the existence of heavy ultramafic cumulates below the Moho has not been resolved yet. In view of these observations different models of magma transport and related paleo-surface topography are discussed.

  11. Relevance of the polymer-induced liquid-precursor (PILP) process to biomineralization and development of biomimetic materials

    NASA Astrophysics Data System (ADS)

    Cheng, Xingguo

    Natural biominerals often contain small amount of acidic macromolecules. These soluble macromolecules are thought to play a very important role in regulating the biomineralization process. By using synthetic acidic biopolymer and natural proteins extracted from biominerals to mimic these acidic macromolecules, the Polymer-Induced Liquid-Precursor (PILP) process is proposed to have great relevance to biomineralization. Like some biominerals, the minerals formed by the PILP process have both non-equilibrium morphology (e.g., "molded" crystal morphologies, films, rods, and tablets) and non-equilibrium composition (e.g., high magnesian calcite). Our goal was to study the formation of calcium carbonate and calcium phosphate formation by the PILP process. By using fluorescence labeling, in-situ observation, and TEM study, we examined the formation of liquid-precursor and polymer-mineral association (exclusion, occlusion). The cooperation of Mg and polymer leads to pronounced amorphous-crystalline transition and formation of thin films incorporating high amount of impurity comparable to biominerals. By taking advantage of amorphous-crystalline transition in the PILP process, calcium carbonate amorphous liquid precursors are molded inside a porous hydrogel and transform to crystalline calcite. After removal of the organic mold, a calcite scaffold with complex morphology is formed. Natural soluble proteins are extracted from nacre. Our in-vitro crystallization studies using these proteins show similar amorphous-crystalline transition and thin film morphology in the presence of Mg. The combination of organic substrate and nacre proteins leads to thin aragonite films. Finally we studied the formation of calcium phosphate using our in-vitro crystallization model. As in the calcium carbonate system, thin films were formed on organic substrate and glass slides in the presence of polymer. We also successfully prepared PHEMA-CaP and collagen-HA organic inorganic composites for

  12. Pristine Igneous Rocks and the Early Differentiation of Planetary Materials

    NASA Technical Reports Server (NTRS)

    Warren, Paul H.

    1998-01-01

    Our studies are highly interdisciplinary, but are focused on the processes and products of early planetary and asteroidal differentiation, especially the genesis of the ancient lunar crust. Most of the accessible lunar crust consists of materials hybridized by impact-mixing. Rare pristine (unmixed) samples reflect the original genetic diversity of the early crust. We studied the relative importance of internally generated melt (including the putative magma ocean) versus large impact melts in early lunar magmatism, through both sample analysis and physical modeling. Other topics under investigation included: lunar and SNC (martian?) meteorites; igneous meteorites in general; impact breccias, especially metal-rich Apollo samples and polymict eucrites; effects of regolith/megaregolith insulation on thermal evolution and geochronology; and planetary bulk compositions and origins. We investigated the theoretical petrology of impact melts, especially those formed in large masses, such as the unejected parts of the melts of the largest lunar and terrestrial impact basins. We developed constraints on several key effects that variations in melting/displacement ratio (a strong function of both crater size and planetary g) have on impact melt petrology. Modeling results indicate that the impact melt-derived rock in the sampled, megaregolith part of the Moon is probably material that was ejected from deeper average levels than the non-impact-melted material (fragmental breccias and unbrecciated pristine rocks). In the largest lunar impacts, most of the impact melt is of mantle origin and avoids ejection from the crater, while most of the crust, and virtually all of the impact-melted crust, in the area of the crater is ejected. We investigated numerous extraordinary meteorites and Apollo rocks, emphasizing pristine rocks, siderophile and volatile trace elements, and the identification of primary partial melts, as opposed to partial cumulates. Apollo 15 sample 15434,28 is an

  13. Igneous origin of K-feldspar Megacrysts in Granitic Rocks of the Sierra Nevada Batholith

    NASA Astrophysics Data System (ADS)

    Moore, J. G.; Sisson, T. W.

    2007-12-01

    Study of the four principal K-feldspar megacrystic granitic plutons and related porphyrys in the Sierra Nevada composite batholith indicates that the included megacrysts are phenocrysts that grew in contact with granitic melt in long-lasting magma chambers. These 89-83 Ma plutons or intrusions are the youngest in the range, and represent the culminating magmatic phase of the batholith. They are the: Granodiorite of Topaz Lake; Cathedral Peak Granodiorite, Mono Creek Granite, Whitney Granodiorite, Johnson Granite Porphyry, and Golden Bear Dike. The zoned megacrysts in each of these igneous bodies attain 4-10 cm in length and all display oscillatory zoning with each zone beginning with a sharp increase followed by a gradual decrease in the concentration of BaO - commonly from 3 to 1 weight percent. Some of the more pronounced zones overlie resorption and channeling features on the underlying zone. Trains of small mineral inclusions (plagioclase, biotite, hornblende, quartz, sphene, and accessory minerals) are parallel to the BaO-delineated zones. The long axes of the inclusions are preferentially aligned parallel to the zone boundaries and inclusions are sorted by size from zone to zone. The growth temperature of sphene included in K-feldspar megacrysts is estimated by use of a Zr-in-sphene geothermometer. The sphene grains all yield igneous temperatures, mainly 735 - 760 °C. Sphene grains in the granodiorite host marginal to the megacrysts range to lower growth temperatures, in some instances into the subsolidus range. The zoning of the megacrysts, their presence in quenched porphry dikes, and the limited range and igneous values of growth temperatures of sphene inclusions within them, support the interpretation that the megacrysts formed as igneous sanidine phenocrysts, and that intrusion temperatures varied by only small amounts while the megacrysts grew. Each Ba- enriched zone was apparently formed by a repeated surge of new, hot melt injected into the large

  14. Simultaneous UV- and ion processing of astrophysically relevant ices. The case of CH3OH:N2 solid mixtures

    NASA Astrophysics Data System (ADS)

    Islam, F.; Baratta, G. A.; Palumbo, M. E.

    2014-01-01

    Context. Interstellar ices are known to be simultaneously processed by both cosmic-ray bombardment and UV photolysis. Our knowledge of the effects of energetic processing on relevant icy samples is mainly based on laboratory investigations. In the past 35 years many experiments have been performed to study these effects separately but, to the best of our knowledge, never simultaneously. Aims: The aim of this work is to study the effects of simultaneous processing of ices by both cosmic rays and UV photons to investigate to what extent the combined effect of ion bombardment and UV photolysis influences the chemical pathways. Methods: We carried out the simultaneous processing of CH3OH:N2 ice held at 16 K by 200 keV H+ ions and Lyman-alpha 10.2 eV UV photons. The samples were analyzed by in situ transmission infrared spectroscopy. The un-combined processes of UV irradiation and bombardment by H+ ions of CH3OH:N2 ice were also studied. This mixture was chosen because the effects of ion bombardment and UV photolysis on methanol and nitrogen have been extensively studied in previous investigations. This mixture enables one to investigate whether simultaneous processing (a) influences the destruction of original species; (b) influences the formation of new species; or (c) causes synergistic effects since Lyman-alpha photons have a very low efficiency in breaking the dinitrogen bond because N2 is almost transparent at Lyman-alpha wavelengths. Results: After processing a CH3OH:N2 sample, the intensity of the methanol bands was observed to decrease at the same rate in all cases. After ion bombardment, species such as CO2, CO, H2CO, CH4, N2O, HNCO, and OCN- are formed in the ice mixture. After UV photolysis, species such as CO2, CO, H2CO, and CH4 are formed, but no N-bearing species are detected. Spectra of ices processed by both UV photons and ions were compared with spectra of ices bombarded only by ions. We find that there are no differences in the band area and profile

  15. Processes relevant for decadal changes in primary production of the North Sea and Baltic Sea: hindcast and scenario modelling

    NASA Astrophysics Data System (ADS)

    Daewel, Ute; Schrum, Corinna; Pushpadas, Dhanya

    2016-04-01

    Despite their geographical vicinity, the North Sea and the Baltic Sea ecosystems exhibit very different characteristics in both physical and biological parameters. Nonetheless, since both ecosystems are characterized by the same general functional groups in phytoplankton and zooplankton and, their geographical distribution indicates comparable thermal adaptation of the plankton groups, we propose that the same ecosystem parameterization can be utilized to simulate the dynamics in both ecosystems simultaneously. Here we present results from an updated version of the 3d coupled ecosystem model ECOSMO valid for both areas. The model allows both multi-decadal hind cast simulation of primary production and specific process studies under controlled environmental conditions. Our results from a long-term hind-cast (1948-2008) indicate incoherent "regime shifts" in the primary productivity (PP) between the North Sea and Baltic Sea. Correlation analysis between atmospheric forcing and PP indicates significant correlations for both solar radiation and wind but cannot serve to identify causal relationship. Therefore additional scenario tests with perturbations in individual atmospheric condition where accomplished emphasizing specifically the role of solar radiation, wind and eutrophication. The results revealed that, although all parameters are relevant for the PP in North Sea and Baltic Sea, the dominant impact on long term variability was introduced by modulations of the wind fields.

  16. Rb-Sr ages of igneous rocks from the Apollo 14 mission and the age of the Fra Mauro formation.

    NASA Technical Reports Server (NTRS)

    Papanastassiou, D. A.; Wasserburg, G. J.

    1971-01-01

    Internal Rb-Sr isochrons were determined on four basaltic rocks and on a basaltic clast from a breccia from the Fra Mauro landing site. An internal isochron was determined for rock 12004 and yielded a value in agreement with previous results for basaltic rocks from the Apollo 12 site. The crystallization ages for Apollo 14 basalts are only 0.2 to 0.3 AE older than were found for mare basalts from the Sea of Tranquility. Assuming these leucocratic igneous rocks to be representative of the Fra Mauro site, it follows that there were major igneous processes active in these regions, and presumably throughout the highlands, at times only slightly preceding the periods at which the maria were last flooded.

  17. Drilling through the largest magma chamber on Earth: Bushveld Igneous Complex Drilling Project (BICDP)

    NASA Astrophysics Data System (ADS)

    Trumbull, R. B.; Ashwal, L. D.; Webb, S. J.; Veksler, I. V.

    2015-05-01

    A scientific drilling project in the Bushveld Igneous Complex in South Africa has been proposed to contribute to the following scientific topics of the International Continental Drilling Program (ICDP): large igneous provinces and mantle plumes, natural resources, volcanic systems and thermal regimes, and deep life. An interdisciplinary team of researchers from eight countries met in Johannesburg to exchange ideas about the scientific objectives and a drilling strategy to achieve them. The workshop identified drilling targets in each of the three main lobes of the Bushveld Complex, which will integrate existing drill cores with new boreholes to establish permanently curated and accessible reference profiles of the Bushveld Complex. Coordinated studies of this material will address fundamental questions related to the origin and evolution of parental Bushveld magma(s), the magma chamber processes that caused layering and ore formation, and the role of crust vs. mantle in the genesis of Bushveld granites and felsic volcanic units. Other objectives are to study geophysical and geodynamic aspects of the Bushveld intrusion, including crustal stresses and thermal gradient, and to determine the nature of deep groundwater systems and the biology of subsurface microbial communities.

  18. Occurrences of igneous rocks in the Adriatic Sea: a possible indicator of the Paleozoic supercontinent disintegration

    NASA Astrophysics Data System (ADS)

    Kudrna Prašek, Marko; Petrinec, Zorica; Balen, Dražen

    2014-05-01

    stratification inside the igneous body, together with a varying degree of alteration (chloritization, uralitization, prehnitization, albitization) and weathering, resulted in slight diversification between the studied sites/samples. The samples gathered during this research are compared to those of wider Mediterranean area (particularly with Moroccan localities) related to the rifting system that lead to the continental breakup and the formation of the oceanic domain. Data obtained here indicate an existing connection between those localities i.e. petrogenetic processes. When all geochemical characteristics are put into previously published, although wide, age context (K-Ar and Ar-Ar ages; ranging 276-200 Ma), correlation of recorded petrogenetic processes with the Triassic magmatism i.e. active continental margin setting (continental breakup) becomes quite tentative. From that perspective these scarce localities inside the Adriatic Sea may be regarded as the easternmost occurrences of Central Atlantic Magmatic Province (CAMP)-like rocks and possibly an important source of information about the processes that accompanied the disintegration of the Paleozoic supercontinent Pangea.

  19. Determination of Fissile Loadings onto Monosodium Titanate (MST) under Conditions Relevant to the Actinide Removal Process Facility

    SciTech Connect

    Peters, T

    2005-11-15

    This report describes the results of an experimental study to measure the sorption of fissile actinides on monosodium titanate (MST) at conditions relevant to operation of the Actinide Removal Process (ARP). The study examined the effect of a single contact of a large volume of radionuclide-spiked simulant solution with a small mass of MST. The volume of simulant to MST (8.5 L to 0.2 g of MST solids) was designed to mimic the maximum phase ratio that occurs between the multiple contacts of MST and waste solution and washing of the accumulated solids cycle of ARP. This work provides the following results. (1) After a contact time of {approx}2 weeks, we measured the following actinide loadings on the MST (average of solution and solids data), Pu: 2.79 {+-} 0.197 wt %, U: 14.0 {+-} 1.04 wt %, and Np: 0.839 {+-} 0.0178 wt %. (2) The plutonium and uranium loadings reported above are considerably higher than previously reported values. The higher loading result from the very high phase ratio and the high initial mass concentrations of uranium and plutonium. A separate upcoming document details the predicted values for this system versus the results. (3) The strontium DF values measured in these tests proved much lower than those reported previously with simulants having the same bulk chemical composition. The low strontium DF values reflect the very low initial mass concentration of strontium in this simulant (<100 {micro}g/L) compared to that in previous testing (> 600 {micro}g/L).

  20. Igneous Intrusion Impacts on Waste Packages and Waste Forms

    SciTech Connect

    P. Bernot

    2004-08-16

    The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The model is based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. This constitutes the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of SR and LA (BSC 2003a) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2002a). The technical work plan is governed by the procedures of AP-SIII.10Q, Models. Any deviations from the technical work plan are documented in the TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model: (1) Impacts of magma intrusion on the components of engineered barrier system (e.g., drip shields and cladding) of emplacement drifts in Zone 1, and the fate of waste forms. (2) Impacts of conducting magma heat and diffusing magma gases on the drip shields, waste packages, and cladding in the Zone 2 emplacement drifts adjacent to the intruded drifts. (3) Impacts of intrusion on Zone 1 in-drift thermal and geochemical environments, including seepage hydrochemistry. The scope of this model only includes impacts to the components stated above, and does not include impacts to other engineered barrier system (EBS) components such as the invert and

  1. Igneous and tectonic evolution of Venusian and terrestrial coronae

    NASA Technical Reports Server (NTRS)

    Kargel, J. S.; Komatsu, G.

    1992-01-01

    A great variety of tectonic and volcanic features have been documented on Venus. It is widely appreciated that there are close spatial associations among certain types of tectonic structures and some classes of volcanic flows and constructs. Coronae are endowed with a particularly rich variety of volcanism. It is thought that coupled tectonic and volcanic aspects of coronae are cogenetic manifestations of mantle plumes. An outstanding feature of most venusian coronae is their circular or elliptical shape defined by peripheral zones of fracturing and/or folding. Some coronae are composite, consisting of two or more small coronae within a larger enclosing corona, suggesting complex histories of structured diapirism analogous in some ways to salt dome tectonics. Coronae range widely in size, from smaller than 100 km to over 1000 km in diameter. Volcanic features associated with venusian coronae include lunar-like sinuous rilles, thin lava flows, cinder cone-like constructs, shield volcanos, and pancake domes. Several types of volcanic features are often situated within or near a single corona, in many instances including land-forms indicating effusions of both low- and high-viscosity lavas. In some cases stratigraphic evidence brackets emplacement of pancake domes during the period of tectonic development of the corona, thus supporting a close link between the igneous and tectonic histories of coronae. These associations suggest emplacement of huge diapirs and massive magmatic intrusions, thus producing the tectonic deformations defining these structures. Igneous differentiation of the intrusion could yield a range of lava compositions. Head and Wilson suggested a mechanism that would cause development of neutral buoyancy zones in the shallow subsurface of Venus, thereby tending to promote development of massive igneous intrusions.

  2. Magnetostriction and palæomagnetism of igneous rocks

    USGS Publications Warehouse

    Graham, John W.; Buddington, A.F.; Balsley, J.R.

    1959-01-01

    IN a recent communication, Stott and Stacey1 report on a “crucial experiment” from which they conclude: “This excellent agreement between the dip and the directions of artificial thermoremanent magnetization of the stressed and unstressed rocks indicates that large systematic errors due to magnetostriction are most improbable in igneous rocks of types normally used for palæomagnetic work”. This experiment was intended to test the proposals2 and measurements3 bearing on the role of magnetostriction in rock magnetism. We present here our reasons for believing that the experiment was not crucial and that the conclusion is not justified.

  3. Magnetic fabric constraints of the emplacement of igneous intrusions

    NASA Astrophysics Data System (ADS)

    Maes, Stephanie M.

    Fabric analysis is critical to evaluating the history, kinematics, and dynamics of geological deformation. This is particularly true of igneous intrusions, where the development of fabric is used to constrain magmatic flow and emplacement mechanisms. Fabric analysis was applied to three mafic intrusions, with different tectonic and petrogenetic histories, to study emplacement and magma flow: the Insizwa sill (Mesozoic Karoo Large Igneous Province, South Africa), Sonju Lake intrusion (Proterozoic Midcontinent Rift, Minnesota, USA), and Palisades sill (Mesozoic rift basin, New Jersey, USA). Multiple fabric analysis techniques were used to define the fabric in each intrusive body. Using digital image analysis techniques on multiple thin sections, the three-dimensional shape-preferred orientation (SPO) of populations of mineral phases were calculated. Low-field anisotropy of magnetic susceptibility (AMS) measurements were used as a proxy for the mineral fabric of the ferromagnetic phases (e.g., magnetite). In addition, a new technique---high-field AMS---was used to isolate the paramagnetic component of the fabric (e.g., silicate fabric). Each fabric analysis technique was then compared to observable field fabrics as a framework for interpretation. In the Insizwa sill, magnetic properties were used to corroborate vertical petrologic zonation and distinguish sub-units within lithologically defined units. Abrupt variation in magnetic properties provides evidence supporting the formation of the Insizwa sill by separate magma intrusions. Low-field AMS fabrics in the Sonju Lake intrusion exhibit consistent SW-plunging lineations and SW-dipping foliations. These fabric orientations provide evidence that the cumulate layers in the intrusion were deposited in a dynamic environment, and indicate magma flowed from southwest to northeast, parallel to the pre-existing rift structures. In the Palisades sill, the magnetite SPO and low-field AMS lineation have developed orthogonal to

  4. Evolution and timing of tectonic events in the Arabia-Eurasia convergence zone as inferred from igneous geochemistry from the EarthChem database

    NASA Astrophysics Data System (ADS)

    Lieu, W. K.; Stern, R. J.

    2011-12-01

    The timing of tectonic events in the Anatolia-Iranian region can be inferred from analysis of igneous rocks. Magmatic activities in the region are generally associated with the convergence of the African-Arabian and Eurasian plates and the subduction of the Neotethys Ocean. Ancillary processes such as subduction of continental crust, delamination of upper plate lithosphere or lower crust, or asthenospheric decompression accompanying post-collisional relaxation also contribute to the composition of igneous rocks. Here we use geochemical data gathered from the EarthChem database to assess broad chemical implications of Cenozoic tectonic activities of the convergence region. We search for geochemical signal of the timing of first contact of the subducting Arabian and overriding Eurasian continental crust. Of particular interest is how igneous rock compositions vary during the transition from pre- to post-contact of the continental crusts. Also, is there a geographic variation along the convergence zone during this tectonic transition? We generate maps and geochemical plots for four different epochs and two different regions since Cenozoic time: Iran and Anatolia in the Eocene, Oligocene, Miocene and Plio-Quaternary. This board, region-scaled analysis of major and trace element patterns suggests the following tectonic events: Subduction-related medium K calc-alkaline igneous rocks reflect Eocene subduction of the Neo-Tethys oceanic lithosphere. Oligocene igneous rocks are characterized by K2O-SiO2 trends scattering to higher silica and alkaline content, which may reflect subduction of stretched continental margin lithosphere and sediments. A bimodal pattern of potash-silica trends during Miocene time may mark the transition from subduction-related to intra-plate magmatism, perhaps signaling contact between the continental crust of Arabia-Africa with Eurasia. Pliocene and younger igneous rocks show an intra-plate and ocean island basalt trend, as the region's activities

  5. Theoretical studies of nonadiabatic and spin-forbidden processes: Investigations of the reactions and spectroscopy of radical species relevant to combustion reactions and diagnostics

    SciTech Connect

    Yarkony, D.R.

    1993-12-01

    This research program focusses on studies of spin-forbidden and electronically nonadiabatic processes involving radical species relevant to combustion reactions and combustion diagnostics. To study the electronic structure aspects of these processes a unique and powerful system of electronic structure programs, developed over the past nine years, the BROOKLYN codes, is employed. These programs enable the authors to address questions basic to the understanding of elementary combustion processes not tractable using more standard quantum chemistry codes.

  6. Modeling differentiation of Karaj Dam basement igneous rocks (northern Iran)

    NASA Astrophysics Data System (ADS)

    Esmaeily, D.; M-Mashhour, R.

    2009-04-01

    The Karaj Dam basement igneous body (KDB) is located in the north of city of Karaj, 30 km from city of Tehran, which lies between 35° 50' N to 36° 05' N and between 50° 50' E to 51° 15' E. It is one of the several plutonic bodies within the E-W trending Alborz zone in northern Iran. Following the late Cretaceous orogenic movements, vast volumes of dacite, andesites and basaltic lavas with tuffaceous and other clastic sediments were deposited during Eocene time, forming Karaj Formation in central Iran and Albourz. The KDB is penetrated thorough middle and upper tuff units from Karaj Formation which is underlain by late Jurassic depositions (Shemshak Formation) and overlain by the Neogene red Conglomerates in regard to stratographic consideration. It is mainly composed of a layered series dominated by gabbro, diorite and monzonite, which is a rock sequence formed upward from the lower to upper chilled margins, respectively. The chilled margins, which have gabbroic in composition, show porphyritic texture with euhedral to subhedral plagioclase (andesine & labradorite) and pyroxene (augite) megacrysts up to 5 mm long. These rocks become coarse-grained inward and transform to equigranular texture gradually.In addition, a small fine-grained doleritic stock as well as some doleritic dykes is intrusive into the pyroclastic volcanic rocks of Karaj Formation. It is possible to observe doleritic enclaves included in the KDB, indicating that the KDB are slightly younger than the dolerites. Whole rock geochemistry and mineral chemistry of the plagioclase and pyroxene in various rock samples, suggest differentiation processes. The Mg# of the pyroxene and An% of plagioclase of the contact chilled samples can be used as an indication of the original magma and plotted between the gabbro and monzonitic samples. In addition, increasing of the Mg# within the whole rock samples from the upper of contact chilled, in comparison to the lower one, demonstrates elemental differentiation

  7. Relevancy 101

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris; Newman, Doug

    2016-01-01

    Where we present an overview on why relevancy is a problem, how important it is and how we can improve it. The topic of relevancy is becoming increasingly important in earth data discovery as our audience is tuned to the accuracy of standard search engines like Google.

  8. Post-igneous redistribution of components in eucrites

    NASA Technical Reports Server (NTRS)

    Phinney, W. C.; Lindstrom, D. J.; Mittlefehldt, D. W.; Martinez, R. R.

    1993-01-01

    In our analyses, we utilize a microdrilling technique that removes 40 to 100 micron diameter cores from mineral grains in thin sections analyzed by microprobe. The cores are then analyzed by INAA using the technique of Lindstrom. Three eucrites were selected for application of this analytical technique: monomict breccias Pasamonte and Stannern and unbrecciated EET90020. Pasamonte is among the most unequilibrated of the eucrites on the basis of zoning in pyroxenes and is considered to be an igneous rock not significantly affected by metamorphism. Stannern has igneous texture but its pyroxenes indicate some re-equilibration, although little, if any, recrystallization. EET90020 has a granulite texture and has been substantially recrystallized. Our sample of Pasamonte contains several clasts of different grain sizes ranging from glass to fine grained with diabasic texture containing lathy plagioclase, unexsolved pigeonite, and mesostasis. Cores were taken of the glass and from minerals and mesostases in six lithic clasts which normally allowed sampling of more than one phase per clast. Our sample of Stannern is also a breccia but with little difference in grain size between clasts and matrix. The plagioclase and pigeonite are blocky, twinned, and exsolved and coexist with a bit of mesostasis. Cores were taken of plagioclase and pigeonite with no attempt to distinguish separate clasts. EET90020 is a granular mixture of twinned plagioclase and pigeonite having rather uniform size and many triple junctions. Several cores were taken of both phases. Both clear and cloudy grains of plagioclase and pyroxene were sampled in all three eucrites.

  9. The High Arctic Large Igneous Province Mantle Plume caused uplift of Arctic Canada

    NASA Astrophysics Data System (ADS)

    Galloway, Jennifer; Ernst, Richard; Hadlari, Thomas

    2016-04-01

    The Sverdrup Basin is an east-west-trending extensional sedimentary basin underlying the northern Canadian Arctic Archipelago. The tectonic history of the basin began with Carboniferous-Early Permian rifting followed by thermal subsidence with minor tectonism. Tectonic activity rejuvenated in the Hauterivian-Aptian by renewed rifting and extension. Strata were deformed by diapiric structures that developed during episodic flow of Carboniferous evaporites during the Mesozoic and the basin contains igneous components associated with the High Arctic Large Igneous Province (HALIP). HALIP was a widespread event emplaced in multiple pulses spanning ca. 180 to 80 Ma, with igneous rocks on Svalbard, Franz Josef Island, New Siberian Islands, and also in the Sverdrup Basin on Ellef Ringnes, Axel Heiberg, and Ellesmere islands. Broadly contemporaneous igneous activity across this broad Arctic region along with a reconstructed giant radiating dyke swarm suggests that HALIP is a manifestation of large mantle plume activity probably centred near the Alpha Ridge. Significant surface uplift associated with the rise of a mantle plume is predicted to start ~10-20 my prior to the generation of flood basalt magmatism and to vary in shape and size subsequently throughout the LIP event (1,2,3) Initial uplift is due to dynamical support associated with the top of the ascending plume reaching a depth of about 1000 km, and with continued ascent the uplift topography broadens. Additional effects (erosion of the ductile lithosphere and thermal expansion caused by longer-term heating of the mechanical lithosphere) also affect the shape of the uplift. Topographic uplift can be between 1 to 4 km depending on various factors and may be followed by subsidence as the plume head decays or become permanent due to magmatic underplating. In the High Arctic, field and geochronological data from HALIP relevant to the timing of uplift, deformation, and volcanism are few. Here we present new evidence

  10. Breakup magmatism style on the North Atlantic Igneous Province: insight from Mid-Norwegian volcanic margin

    NASA Astrophysics Data System (ADS)

    Mansour Abdelmalak, Mohamed; Faleide, Jan Inge; Planke, Sverre; Theissen-Krah, Sonja; Zastrozhnov, Dmitrii; Breivik, Asbjørn Johan; Gernigon, Laurent; Myklebust, Reidun

    2014-05-01

    The distribution of breakup-related igneous rocks on rifted margins provide important constraints on the magmatic processes during continental extension and lithosphere separation which lead to a better understanding of the melt supply from the upper mantle and the relationship between tectonic setting and volcanism. The results can lead to a better understanding of the processes forming volcanic margins and thermal evolution of associated prospective basins. We present a revised mapping of the breakup-related igneous rocks in the NE Atlantic area, which are mainly based on the Mid-Norwegian (case example) margin. We divided the breakup related igneous rocks into (1) extrusive complexes, (2) shallow intrusive complexes (sills/dykes) and (3) deep intrusive complexes (Lower Crustal Body: LCB). The extrusive complex has been mapped using the seismic volcanostratigraphic method. Several distinct volcanic seismic facies units have been identified. The top basalt reflection is easily identified because of the high impedance contrast between the sedimentary and volcanic rocks resulting in a major reflector. The basal sequence boundary is frequently difficult to identify but it lies usually over the intruded sedimentary basin. Then the base is usually picked above the shallow sill intrusions identified on seismic profile. The mapping of the top and the base of the basaltic sequences allows us to determine the basalt thickness and estimate the volume of the magma production on the Mid- Norwegian margin. The thicker part of the basalt corresponds to the seaward dipping reflector (SDR). The magma feeder system, mainly formed by dyke and sill intrusions, represents the shallow intrusive complex. Deeper interconnected high-velocity sills are also mappable in the margin. Interconnected sill complexes can define continuous magma network >10 km in vertical ascent. The large-scale sill complexes, in addition to dyke swarm intrusions, represent a mode of vertical long-range magma

  11. Venus - Chemical weathering of igneous rocks and buffering of atmospheric composition

    NASA Technical Reports Server (NTRS)

    Nozette, S.; Lewis, J. S.

    1982-01-01

    Data from the Pioneer Venus radar mapper, combined with measurements of wind velocity and atmospheric composition, suggest that surface erosion on Venus varies with altitude. Calcium- and magnesium-rich weathering products are produced at high altitudes by gas-solid reactions with igneous minerals, then removed into the hotter lowlands by surface winds. These fine-grained weathering products may then rereact with the lower atmosphere and buffer the composition of the observed gases carbon dioxide, water vapor, sulfur dioxide, and hydrogen fluoride in some regions of the surface. This process is a plausible mechanism for the establishment in the lowlands of a calcium-rich mineral assemblage, which had previously been found necessary for the buffering of these species.

  12. An Igneous Origin for Features of a Candidate Crater-Lake System in Western Memnonia, Mars

    NASA Technical Reports Server (NTRS)

    Leverington, D. W.; Maxwell, T. A.

    2004-01-01

    The association of channels, inner terraces, and delta-like features with Martian impact craters has previously been interpreted as evidence in favor of the past existence of crater lakes on Mars. However, examination of a candidate crater-lake system in western Memnonia suggests instead that its features may have formed through igneous processes involving the flow and ponding of lava. Accumulations of material in craters and other topographic lows throughout much of the study region have characteristics consistent with those of volcanic deposits, and terraces found along the inner flanks of some of these craters are interpreted as having formed through drainage or subsidence of volcanic materials. Channels previously identified as inlets and outlets of the crater-lake system are interpreted instead as volcanic rilles. These results challenge previous interpretations of terrace and channel features in the study region and suggest that candidate crater lakes located elsewhere should be reexamined.

  13. Venus: chemical weathering of igneous rocks and buffering of atmospheric composition.

    PubMed

    Nozette, S; Lewis, J S

    1982-04-01

    Data from the Pioneer Venus radar mapper, combined with measurements of wind velocity and atmospheric composition, suggest that surface erosion on Venus varies with altitude. Calcium- and magnesium-rich weathering products are produced at high altitudes by gas-solid reactions with igneous minerals, then removed into the hotter lowlands by surface winds. These fine-grained weathering products may then rereact with the lower atmosphere and buffer the composition of the observed gases carbon dioxide, water vapor, sulfur dioxide, and hydrogen fluoride in some regions of the surface. This process is a plausible mechanism for the establishment in the lowlands of a calcium-rich mineral assemblage, which had previously been found necessary for the buffering of these species. PMID:17736250

  14. Mafic and felsic igneous rocks at Gale crater

    NASA Astrophysics Data System (ADS)

    Sautter, Violaine; Cousin, Agnès; Mangold, Nicolas; Toplis, Michael; Fabre, Cécile; Forni, Olivier; Payré, Valérie; Gasnault, Olivier; Ollila, Anne; Rapin, William; Fisk, Martin; Meslin, Pierre-Yves; Wiens, Roger; Maurice, Sylvestre; Lasue, Jérémie; Newsom, Horton; Lanza, Nina

    2015-04-01

    The Curiosity rover landed at Gale, an early Hesperian age crater formed within Noachian terrains on Mars. The rover encountered a great variety of igneous rocks to the west of the Yellow Knife Bay sedimentary unit (from sol 13 to 800) which are float rocks or clasts in conglomerates. Textural and compositional analyses using MastCam and ChemCam Remote micro Imager (RMI) and Laser Induced Breakdown Spectroscopy (LIBS) with a ˜300-500 µm laser spot lead to the recognition of 53 massive (non layered) igneous targets, both intrusive and effusive, ranging from mafic rocks where feldspars form less than 50% of the rock to felsic samples where feldspar is the dominant mineral. From morphology, color, grain size, patina and chemistry, at least 5 different groups of rocks have been identified: (1) a basaltic class with shiny aspect, conchoidal frature, no visible grains (less than 0.2mm) in a dark matrix with a few mm sized light-toned crystals (21 targets) (2) a porphyritic trachyandesite class with light-toned, bladed and polygonal crystals 1-20 mm in length set in a dark gray mesostasis (11 targets); (3) light toned trachytes with no visible grains sometimes vesiculated or forming flat targets (6 targets); (4) microgabbro-norite (grain size < 1mm) and gabbro-norite (grain size >1 mm) showing dark and light toned crystals in similar proportion ( 8 targets); (5) light-toned diorite/granodiorite showing coarse granular (>4 mm) texture either pristine or blocky, strongly weathered rocks (9 rock targets). Overall, these rocks comprise 2 distinct geochemical series: (i) an alkali-suite: basanite, gabbro trachy-andesite and trachyte) including porphyritic and aphyric members; (ii) quartz-normative intrusives close to granodioritic composition. The former looks like felsic clasts recently described in two SNC meteorites (NWA 7034 and 7533), the first Noachian breccia sampling the martian regolith. It is geochemically consistent with differentiation of liquids produced by low

  15. Rb-Sr age of lunar igneous rocks 62295 and 14310

    NASA Technical Reports Server (NTRS)

    Mark, R. K.; Lee-Hu, C.-N.; Wetherill, G. W.

    1974-01-01

    Measurements of Rb-Sr ages of crystallization performed on igneous lunar highland rocks 62295 and 14310 are reported. Lunar sample 62295 is a mesostasis-rich spinel-troctolite very-high-alumina basalt exhibiting a variable igneous structure. Sample 14310 is a feldspathic KREEP-rich basalt. The determined ages probably date the cooling of shock melts.

  16. The "Key" Method of Identifying Igneous and Metamorphic Rocks in Introductory Laboratory.

    ERIC Educational Resources Information Center

    Eves, Robert Leo; Davis, Larry Eugene

    1987-01-01

    Proposes that identification keys provide an orderly strategy for the identification of igneous and metamorphic rocks in an introductory geology course. Explains the format employed in the system and includes the actual key guides for both igneous and metamorphic rocks. (ML)

  17. Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith

    USGS Publications Warehouse

    Moore, J.G.; Sisson, T.W.

    2008-01-01

    interpretation that the megacrysts formed ag igneous sanidine phenocrysts, that intrusion temperatures varied by only small amounts while the megacrysts grew, and that megacryst growth ceased before the intrusions cooled below the solidus. Individual Ba-enriched zones were apparently formed by repeated surges of new, hotter granitic melt that replenished these large magma chambers. Each recharge of hot magron offset cooling, maintained the partially molten or mushy character of the chamber, stirred up crystals, and induced convective currents that lofted, settling megacrysts back up into the chamber. Because of repeated reheating of the magma chamber and prolonged maintenance of the melt, this process apparently continued long enough to provide the ideal environment for the growth of these extraordinarily large K-feldspar phenocrysts. ??2008 Geological Society of America.

  18. The key role of mica during igneous concentration of tantalum

    NASA Astrophysics Data System (ADS)

    Stepanov, Aleksandr; A. Mavrogenes, John; Meffre, Sebastien; Davidson, Paul

    2014-06-01

    Igneous rocks with high Ta concentrations share a number of similarities such as high Ta/Nb, low Ti, LREE and Zr concentrations and granitic compositions. These features can be traced through fractionated granitic series. Formation of Ta-rich melts begins with anatexis in the presence of residual biotite, followed by magmatic crystallization of biotite and muscovite. Crystallization of biotite and muscovite increases Ta/Nb and reduces the Ti content of the melt. Titanium-bearing oxides such as rutile and titanite are enriched in Ta and have the potential to deplete Ta at early stages of fractionation. However, mica crystallization suppresses their saturation and allows Ta to increase in the melt. Saturation with respect to Ta and Nb minerals occurs at the latest stages of magmatic crystallization, and columbite can originate from recrystallization of mica. We propose a model for prediction of intrusion fertility for Ta.

  19. Major and trace elements in igneous rocks from Apollo 15.

    NASA Technical Reports Server (NTRS)

    Helmke, P. A.; Blanchard, D. P.; Haskin, L. A.; Telander, K.; Weiss, C.; Jacobs, J. W.

    1973-01-01

    The concentrations of major and trace elements have been determined in igneous rocks from Apollo 15. All materials analyzed have typical depletions of Eu except for minerals separated from sample 15085. Four samples have concentrations of trace elements that are similar to those of KREEP. The samples of mare basalt from Apollo 15 have higher concentrations of FeO, MgO, Mn, and Cr and lower concentrations of CaO, Na2O, K2O, and rare-earth elements (REE) as compared to the samples of mare basalt from Apollos 11, 12, and 14. The samples can be divided into two groups on the basis of their normative compositions. One group is quartz normative and has low concentrations of FeO while the other is olivine normative and has high concentrations of FeO. The trace element data indicate that the samples of olivine normative basalt could be from different portions of a single lava flow.

  20. The Search for Igneous Materials at the Viking Landing Sites

    NASA Technical Reports Server (NTRS)

    Arvidson, R. E.; Dale-Bannister, M.; Guinnes, E. A.

    1985-01-01

    The use of Viking Lander 6 channel (0.4 to 1.1 microns) images to identify igneous materials is discussed. Movies of synthetic image cubes demonstrate that there are a number of contrast reversals between soils and certain rocks. Typically, large, angular rocks are brighter than the surrounding soils in the shortest wavelengths, and much darker than the soils at longest wavelengths. These results, which seem difficult to explain solely on the basis of photometric effects related to local lighting and viewing, are consistent with the presence of Fe+2 bearing silicates at the rock surfaces, producing relatively moderate absorptions in the blue and green parts of the spectrum, but more significant absorptions near about 1.0 micrometer (e.g., Fe+2 bearing pyroxenes). The soils, on the other hand, have signatures consistent with strong Fe+3 related absorptions at shorter wavelengths (e.g., Fe+3 bearing oxides or hydroxides).

  1. The nakhlite meteorites: Augite-rich igneous rocks from Mars

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.

    2005-01-01

    The seven nakhlite meteorites are augite-rich igneous rocks that formed in flows or shallow intrusions of basaltic magma on Mars. They consist of euhedral to subhedral crystals of augite and olivine (to 1 cm long) in fine-grained mesostases. The augite crystals have homogeneous cores of Mg' = 63% and rims that are normally zoned to iron enrichment. The core-rim zoning is cut by iron-enriched zones along fractures and is replaced locally by ferroan low-Ca pyroxene. The core compositions of the olivines vary inversely with the steepness of their rim zoning - sharp rim zoning goes with the most magnesian cores (Mg' = 42%), homogeneous olivines are the most ferroan. The olivine and augite crystals contain multiphase inclusions representing trapped magma. Among the olivine and augite crystals is mesostasis, composed principally of plagioclase and/or glass, with euhedra of titanomagnetite and many minor minerals. Olivine and mesostasis glass are partially replaced by veinlets and patches of iddingsite, a mixture of smectite clays, iron oxy-hydroxides and carbonate minerals. In the mesostasis are rare patches of a salt alteration assemblage: halite, siderite, and anhydrite/ gypsum. The nakhlites are little shocked, but have been affected chemically and biologically by their residence on Earth. Differences among the chemical compositions of the nakhlites can be ascribed mostly to different proportions of augite, olivine, and mesostasis. Compared to common basalts, they are rich in Ca, strongly depleted in Al, and enriched in magmaphile (incompatible) elements, including the LREE. Nakhlites contain little pre-terrestrial organic matter. Oxygen isotope ratios are not terrestrial, and are different in anhydrous silicates and in iddingsite. The alteration assemblages all have heavy oxygen and heavy carbon, while D/H values are extreme and scattered. Igneous sulfur had a solar-system isotopic ratio, but in most minerals was altered to higher and lower values. High precision

  2. Primary igneous rocks on Mars: Composition and distribution

    NASA Technical Reports Server (NTRS)

    Singer, Robert B.; Mcsween, Harry Y., Jr.

    1991-01-01

    The present knowledge of the crustal composition of Mars is synthesized and implications discussed for in-situ resource utilization. Sources of information include remote sensing observations, Viking XRF chemical measurements, and characteristics of the SNC meteorites (which most researchers now believe originated on Mars). There are a number of lines of evidence that abundant ferrous-iron rich igneous crustal rocks (and derivative soils) are available at or very near the current Martian surface at many locations on the planet. Most of these exposures show spectroscopic evidence for abundant pyroxene, consistent with basaltic compositions. The SNC meteorites, which have basaltic compositions, were also studied extensively. Interpretations of Mars crustal chemistry and mineralogy (petrology) based on these various sources are reviewed, and their consistencies and differences are discussed.

  3. On the original igneous source of Martian fines

    NASA Technical Reports Server (NTRS)

    Baird, A. K.; Clark, B. C.

    1981-01-01

    The composition of the silicate portion of Martian regolith fines indicates derivation of the fines from mafic to ultramafic rocks, probably rich in pyroxene. Rock types similar in chemical and mineralogical composition include terrestrial Archean basalts and certain achondrite meteorites. If these igneous rocks weathered nearly isochemically, the nontronitic clays proposed earlier as an analog to Martian fines could be formed. Flood basalts of pyroxenitic lavas may be widespread and characteristic of early volcanism on Mars, analogous to maria flood basalts on the moon and early Precambrian basaltic komatiites on earth. Compositional differences between lunar, terrestrial, and Martian flood basalts may be related to differences in planetary sizes and mantle compositions of the respective planetary objects.

  4. Igneous intrusion models for floor fracturing in lunar craters

    NASA Technical Reports Server (NTRS)

    Wichman, R. W.; Schultz, P. H.

    1991-01-01

    Lunar floor-fractured craters are primarily located near the maria and frequently contain ponded mare units and dark mantling deposits. Fracturing is confined to the crater interior, often producing a moat-like feature near the floor edge, and crater depth is commonly reduced by uplift of the crater floor. Although viscous relaxation of crater topography can produce such uplift, the close association of modification with surface volcanism supports a model linking floor fracture to crater-centered igneous intrusions. The consequences of two intrusion models for the lunar interior are quantitatively explored. The first model is based on terrestrial laccoliths and describes a shallow intrusion beneath the crater. The second model is based on cone sheet complexes where surface deformation results from a deeper magma chamber. Both models, their fit to observed crater modifications and possible implications for local volcanism are described.

  5. Magnetic anomalies along the contact between sedimentary and igneous rocks:

    NASA Astrophysics Data System (ADS)

    Kletetschka, G.; Speer, A. J.; Wasilewski, P. J.

    2002-05-01

    Intrusion of the Liberty Hill granite (South Carolina) into the surrounding shale causes a distinct aureole along the metamorphic contact. The aureole is divided by five isograds, which are the result of a sequence of continuous reactions. One consequence of the continuous reactions is production of contrasting proportion of magnetite and exsolved titanohematite. The continuous change in the relative amounts of these two minerals, controls the magnetic properties of the hornfelses. This causes magnetic anomaly changes associated with the aureole with inflexions occurring at the isograds. The maximum intensity of the magnetic anomaly coincides with the maximum abundance of titanohematite. The anomaly sharply drops when stable remanence of titanohematite is replaced by unstable remanence of magnetite. Magnetic properties of the aureole, which is the contact between igneous and sedimentary rocks, demonstrate an example of magnetic remanence acquisition in petrological environment that is likely to occur on planet Mars.

  6. Evolution of the martian mantle as recorded by igneous rocks

    NASA Astrophysics Data System (ADS)

    Balta, J. B.; McSween, H. Y.

    2013-12-01

    Martian igneous rocks provide our best window into the current state of the martian mantle and its evolution after accretion and differentiation. Currently, those rocks have been examined in situ by rovers, characterized in general from orbiting spacecraft, and analyzed in terrestrial laboratories when found as meteorites. However, these data have the potential to bias our understanding of martian magmatism, as most of the available meteorites and rover-analyzed rocks come from the Amazonian (<2 Ga) and Hesperian (~3.65 Ga) periods respectively, while igneous rocks from the Noachian (>3.8 Ga) have only been examined by orbiters and as the unique meteorite ALH 84001. After initial differentiation, the main planetary-scale changes in the structure of Mars which impact igneous compositions are cooling of the planet and thickening of the crust with time. As the shergottite meteorites give ages <500 Ma1, they might be expected to represent thick-crust, recent volcanism. Using spacecraft measurements of volcanic compositions and whole rock compositions of meteorites, we demonstrate that the shergottite meteorites do not match the composition of the igneous rocks composing the young volcanoes on Mars, particularly in their silica content, and no crystallization or crustal contamination trend reproduces the volcanoes from a shergottite-like parent magma. However, we show that the shergottite magmas do resemble older martian rocks in composition and mineralogy. The Noachian-aged meteorite ALH 84001 has similar radiogenic-element signatures to the shergottites and may derive from a similar mantle source despite the age difference2. Thus, shergottite-like magmas may represent melting of mantle sources that were much more abundant early in martian history. We propose that the shergottites represent the melting products of an originally-hydrous martian mantle, containing at least several hundred ppm H2O. Dissolved water can increase the silica content of magmas and thus

  7. Chip-off-the-old-rock: the study of reservoir-relevant geological processes with real-rock micromodels.

    PubMed

    Song, Wen; de Haas, Thomas W; Fadaei, Hossein; Sinton, David

    2014-11-21

    We present a real-rock micromodel approach whereby microfluidic channels are fabricated in a naturally occurring mineral substrate. The method is applied to quantify calcite dissolution which is relevant to oil/gas recovery, CO2 sequestration, and wastewater disposal in carbonate formations - ubiquitous worldwide. The key advantage of this method is the inclusion of both the relevant substrate chemistry (not possible with conventional microfluidics) and real-time pore-scale resolution (not possible with core samples). Here, microchannels are etched into a natural calcite crystal and sealed with a glass slide. The approach is applied to study acidified brine flow through a single channel and a two-dimensional micromodel. The single-channel case conforms roughly to a 1-D analytical description, with crystal orientation influencing the local dissolution rate an additional 25%. The two-dimensional experiments show highly flow-directed dissolution and associated positive feedback wherein acid preferentially invades high conductivity flow paths, resulting in higher dissolution rates ('wormholing'). These experiments demonstrate and validate the approach of microfabricating fluid structures within natural minerals for transport and geochemical studies. More broadly, real-rock microfluidics open the door to a vast array of lab-on-a-chip opportunities in geology, reservoir engineering, and earth sciences. PMID:25236399

  8. Constraining the History of the North Atlantic Igneous Province: a Palaeomagnetic and Geochronologic Ballad in the British Tertiary Volcanics.

    NASA Astrophysics Data System (ADS)

    Ganerød, M.; Rousse, S.; Smethurst, M.; Prestvik, T.

    2006-12-01

    Large Igneous Provinces (LIP), overwhelmingly of basaltic affinity constitute the surface expressions of catastrophically rapid dissipation of large quantities of internal heat. Subsequent to their extrusion, most LIPs have changed position in the Earth's surface due to plate motions. With an estimated volume of ca 107 km3 the North Atlantic Igneous Province (NAIP) represents the third largest magmatic event on Earth during the last 150 Myr. The NAIP formed during two major magmatic phases: a pre- break-up phase (62-58 Ma) and a syn- break-up phase (56-54 Ma) contemporaneous with the onset of North Atlantic sea-floor spreading. The formation of the NAIP has been linked to the proto-Icelandic plume through paleogeographic reconstructions and geochemical observations. Since the late 1980's much of the research focus on the NAIP has been guided by the understanding of the genetic relationship between North Atlantic magmatism that began in the earliest Palaeocene, the genesis/position of the Iceland Hotspots and/or related mantle plume(s) through the Cenozoic, and the change at c. 54 Ma from a long period of continental rifting and thinning of sea- floor spreading. However, despite the number of data available, the temporal and physio-chemical ties between NAIP rocks, hotspot motion and continental break-up have not been demonstrated to fit a single regionally applicable and consistent geodynamic model. For example, discrepancies between recent palaeomagnetic poles from western Greenland and the Faeroe Islands (Riisager et al. 2002a,b) and older data from the British Tertiary Igneous Province (BTIP) have questioned the reliability of the latest. Therefore, to ultimately understand the Tertiary evolution of the North Atlantic, extensive palaeomagnetic and 40Ar/39Ar sampling on the lava fields of the British Igneous Provinces (Isle of Skye, Isle of Mull, Antrim Plateau) has been initiated. Our findings are in agreement with older published poles from the BTIP and support

  9. The Eastern Iowa Community College District Program Evaluation Process: A Vital and Practical Tool for Ensuring Program Relevancy.

    ERIC Educational Resources Information Center

    Friedel, Janice Nahra

    The process developed and implemented by the Eastern Iowa Community College District (EICCD) to evaluate its vocational and technical programs is described. The process provides for the flow of information and recommendations from the faculty through administrative ranks to the Chancellor of the District. The EICCD is comprised of three colleges…

  10. Processing Coordinated Verb Phrases: The Relevance of Lexical-Semantic, Conceptual, and Contextual Information towards Establishing Verbal Parallelism

    ERIC Educational Resources Information Center

    Tutunjian, Damon A.

    2010-01-01

    This dissertation examines the influence of lexical-semantic representations, conceptual similarity, and contextual fit on the processing of coordinated verb phrases. The study integrates information gleaned from current linguistic theory with current psycholinguistic approaches to examining the processing of coordinated verb phrases. It has…

  11. IGNEOUS INTRUSION IMPACTS ON WASTE PACKAGES AND WASTE FORMS

    SciTech Connect

    P. Bernot

    2004-04-19

    The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The models are based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. The models described in this report constitute the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of LA (BSC 2004 [DIRS:167796]) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2003 [DIRS: 166296]). The technical work plan was prepared in accordance with AP-2.27Q, Planning for Science Activities. Any deviations from the technical work plan are documented in the following sections as they occur. The TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model assessments: (1) Mechanical and thermal impacts of basalt magma intrusion on the invert, waste packages and waste forms of the intersected emplacement drifts of Zone 1. (2) Temperature and pressure trends of basaltic magma intrusion intersecting Zone 1 and their potential effects on waste packages and waste forms in Zone 2 emplacement drifts. (3) Deleterious volatile gases, exsolving from the intruded basalt magma and their potential effects on waste packages of Zone 2 emplacement drifts. (4) Post-intrusive physical

  12. Relevance of the time-quasi-polynomials in the classic linear thermodynamic theory of coupled transport processes

    NASA Astrophysics Data System (ADS)

    Mészáros, Cs.; Kirschner, I.; Bálint, Á.

    2014-07-01

    A general description of the basic system of ordinary differential equations of coupled transport processes is given within framework of a linear approximation and treated by tools of matrix analysis and group representation theory. It is shown that the technique of hyperdyads directly generalizes the method of simple dyadic decomposition of operators used earlier in the classical linear irreversible thermodynamics and leads to possible new applications of the concept of quasi-polynomials at descriptions of coupled transport processes.

  13. Complete Analytical Data for Samples of Jurassic Igneous Rocks in the Bald Mountain Mining District, Nevada

    USGS Publications Warehouse

    du Bray, Edward A.

    2009-01-01

    This report presents all petrographic, major oxide, and trace element data for a set of 109 samples collected during an investigation of Jurassic igneous rocks in the Bald Mountain mining district, Nevada. Igneous rocks in the district include the Bald Mountain stock, quartz-feldspar porphyry dikes, basaltic andesite dikes, aplite sills, and rare lamprophyre dikes. These rocks, although variably altered near intrusion-related mineral deposits, are fresh in many parts of the district. Igneous rocks in the district are hosted by Paleozoic sedimentary rocks.

  14. Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

    SciTech Connect

    F. Perry; B. Youngs

    2000-11-06

    The purpose of this Analysis/Model (AMR) report is twofold. (1) The first is to present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the Probabilistic Volcanic Hazard Analysis (PVHA) (CRWMS M&O 1996). Conceptual models presented in the PVHA are summarized and extended in areas in which new information has been presented. Alternative conceptual models are discussed as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) The second purpose of the AMR is to present probability calculations based on PVHA outputs. Probability distributions are presented for the length and orientation of volcanic dikes within the repository footprint and for the number of eruptive centers located within the repository footprint (conditional on the dike intersecting the repository). The probability of intersection of a basaltic dike within the repository footprint was calculated in the AMR ''Characterize Framework for Igneous Activity at Yucca Mountain, Nevada'' (CRWMS M&O 2000g) based on the repository footprint known as the Enhanced Design Alternative [EDA II, Design B (CRWMS M&O 1999a; Wilkins and Heath 1999)]. Then, the ''Site Recommendation Design Baseline'' (CRWMS M&O 2000a) initiated a change in the repository design, which is described in the ''Site Recommendation Subsurface Layout'' (CRWMS M&O 2000b). Consequently, the probability of intersection of a basaltic dike within the repository footprint has also been calculated for the current repository footprint, which is called the 70,000 Metric Tons of Uranium (MTU) No-Backfill Layout (CRWMS M&O 2000b). The calculations for both footprints are presented in this AMR. In addition, the

  15. Perceived Parenting Dimensions and Identity Styles: Exploring the Socialization of Adolescents' Processing of Identity-Relevant Information

    ERIC Educational Resources Information Center

    Smits, Ilse; Soenens, Bart; Luyckx, Koen; Duriez, Bart; Berzonsky, Michael; Goossens, Luc

    2008-01-01

    This study examined the relationships between crucial dimensions of perceived parenting (support, behavioral control, and psychological control) and the three identity styles defined by Berzonsky [Berzonsky, M. D. (1990). "Self-construction over the life span: A process perspective on identity formation." "Advances in Personal Construct…

  16. Calcium isotopes in igneous rocks and the origin of granite

    SciTech Connect

    Marshall, B.D.; DePaolo, D.J. )

    1989-04-01

    The K-Ca radioactive parent-daughter system provides a tool for tracing the origins of igneous rocks. It is complementary to other isotopic systems because as stoichiometric constituents of major minerals, the concentrations of K and Ca, and the K/Ca ratio in rocks, are simply related to mineralogy. In this paper the authors report the first high-precision calcium isotopic analyses of continental granitic rocks, island arc rocks, and mid-ocean ridge basalts. These data show that mid-ocean ridge basalts have the low {sup 40}Ca/{sup 42}Ca ratios expected for the Earth's mantle, but that island arc rocks have slightly higher {sup 40}Ca/{sup 42}Co ratios indicative of crustal calcium in their magma sources. Many granitic rocks have high initial {sup 40}Ca/{sup 42}Ca ratios, and in conjunction with independent evidence for the age of the crustal sources, these ratios provide constraints on the K/Ca ratios, and in turn on the silica contents and residual mineralogy, of the deep crustal magma sources.

  17. The Igneous SPICEs Suite: Old Programs with a New Look

    NASA Astrophysics Data System (ADS)

    Davenport, J. D.

    2013-12-01

    Understanding the chemistry of magma is important for understanding how the planets differentiated into crusts, rocky mantles, and metallic cores. Magma formation and crystallization can be modeled using computer programs. A valuable and useful set of programs was developed by John Longhi (Lamont-Doherty Earth Observatory, Palisades, New York). John Longhi generously shared these programs widely with colleagues, but they were written in Fortran by John for his own use, and not as user-friendly research tools. As a major part of my Masters thesis at the University of Notre Dame, I was using the programs to do numerous calculations of the crystallization of the lunar magma ocean, the deep, global magma layer surrounding the Moon when it formed. It occurred to me that it would make my life easier if the programs were more straightforward, so working with others at Notre Dame and elsewhere, including John Longhi, I converted the programs for use with MATLAB, a powerful mathematical program. The revisions (Simulating Planetary Igneous Crystallization Environments, SPICEs) have a simple graphical interface for ease of input and output, yet use the same rigorous calculations in the original Longhi programs. My goal is to make the programs more widely used for research and education.

  18. Large Igneous Provinces, Sulfur Aerosols, and Initiation of Snowball Earth

    NASA Astrophysics Data System (ADS)

    Macdonald, F. A.; Wordsworth, R. D.

    2015-12-01

    The events that led to the initiation of Snowball Earth remain poorly understood. Proposed scenarios include a methane addiction, a biological innovation that led to an increase in organic carbon burial and anaerobic remineralization, or an increase in global weatherability due to a paleogeography with a preponderance of low latitude continents, and the subareal implacement of large igneous provinces (LIPs) at the equator. The Franklin LIP was emplaced between 730 and 710 Ma and covers an area of over 2.25 Mkm2 with lavas, sills, and dikes extending over much of northern Laurentia from Alaska through northern Canada to Greenland and potentially to Siberia. The most precise geochronological constraints on the Franklin LIP overlap with the onset of the Sturtian Snowball Earth glaciation, which began between 717 and 716 Ma and marked the first glaciation in over 1 billion years. The Franklin LIP is the largest preserved Neoproterozoic LIP and one of the largest in Earth History. Additionally, it was emplaced at equatorial latitudes with associated sills that invaded epicontinental sulfur evaporite basins, potentially maximizing environmental effects. Here we explore the hypothesis that the Sturtian Snowball Earth was initiated in part by an increase in planetary albedo from the conversion of volcanic SO2/H2S emissions to tropospheric and stratospheric sulfate aerosols through a combination of geochemical and modeling studies.

  19. Thermal diffusivity of igneous rocks at elevated pressure and temperature

    SciTech Connect

    Durham, W.B.; Mirkovich, V.V.; Heard, H.C.

    1987-10-10

    Thermal diffusivity measurements of seven igneous rocks were made to temperatures of 400 /sup 0/C and pressures of 200 MPa. The measuring method was based on the concept of cylindrical symmetry and periodic heat pulses. The seven rocks measured were Westerly (Rhode Island) granite, Climax Stock (Nevada) quartz monzonite, Pomona (Washington) basalt, Atikokan (Ontario, Canada) granite, Creighton (Ontario, Canada) gabbro, East Bull Lake (Ontario, Canada) gabbro, and Stripa (Sweden) granite. The diffusivity of all the rocks showed a positive linear dependence on inverse temperature and, excluding the East Bull Lake gabbro, showed a linear dependence on quartz content. (Quartz content varied from 0 to 31% by volume.) Diffusivity in all cases rose or remained steady with increasing confining pressure. The pressure effect was strongest at lowest pressures and vanished by levels between 10 and 100 MPa, depending on rock type. The pressure effect (measured as a percentage change in diffusivity) is stronger in the four rocks of granite composition than in the three of basaltic composition. Our results agree well with existing thermal diffusivity measurements at atmospheric pressure.

  20. Seeing (and Inferring) is Believing: Using the Nature of Science to reinforce process skills and teach relevant science content.

    NASA Astrophysics Data System (ADS)

    Egge, Noah; Bell, Randy

    2010-05-01

    If science education can be compared to building a house, then conceptually it can be divided into three parts: content knowledge, process skills, and nature of science or science as a way of thinking. The basis of understanding any discipline begins with the accumulation of facts, theories and concepts. These are the building blocks which are used to construct and strengthen a foundation. Next are the investigatory processes and the methods; these are the tools necessary to create new knowledge and enable students to strengthen and expand their foundation. Closely linked with processes and methods are the values and assumptions that are intertwined with interpretations and conclusions. Students must be taught that science is not infallible or an absolute field. Theories and relationships are created and refuted based on the availability of data, and are heavily laden with personal and cultural bias. Teachers need to emphasize the importance of the different aspects of the nature of science—for example the connection between creativity and science—so that students will know there is not merely a single set of blueprints to build the house but an infinite number that merely await discovery. In the United States, the National Science Education Standards recognize the importance of the nature of science as an instructional objective. As a consequence many states have incorporated the nature of science into their standards. In this presentation we will clarify what is meant by "nature of science" and relate it to the more traditional topics of science content and process skills. The focus of the presentation will be on introducing a sequence of teacher-tested activities designed for middle and secondary school students. These activities address specific aspects of the nature of science; they are designed to be engaging and student-centered and to link abstract concepts of the nature of science to more familiar science process-skills.

  1. Neutron capture reactions relevant to the s and p processes in the region of the N =50 shell closure

    NASA Astrophysics Data System (ADS)

    Dutta, Saumi; Gangopadhyay, G.; Bhattacharyya, Abhijit

    2016-08-01

    The radiative neutron capture cross sections for nuclei participating in the s -process and the p -process nucleosynthesis in and around the N =50 closed neutron shell have been calculated in a statistical semimicroscopic Hauser-Feshbach approach for the energy range of astrophysical interest. A folded optical-model potential is constructed utilizing the standard DDM3Y real nucleon-nucleon interaction. The folding of the interaction with target radial matter densities, obtained from the relativistic mean-field theory, is done in coordinate space using the spherical approximation. The standard nuclear reaction code talys1.8 is used for cross-section calculation. The cross sections are compared with experimental results. Maxwellian-averaged cross sections and astrophysical reaction rates for a number of selected nuclei are also presented.

  2. Intentional action processing results from automatic bottom-up attention: An EEG-investigation into the Social Relevance Hypothesis using hypnosis.

    PubMed

    Neufeld, Eleonore; Brown, Elliot C; Lee-Grimm, Sie-In; Newen, Albert; Brüne, Martin

    2016-05-01

    Social stimuli grab our attention. However, it has rarely been investigated how variations in attention affect the processing of social stimuli, although the answer could help us uncover details of social cognition processes such as action understanding. In the present study, we examined how changes to bottom-up attention affects neural EEG-responses associated with intentional action processing. We induced an increase in bottom-up attention by using hypnosis. We recorded the electroencephalographic μ-wave suppression of hypnotized participants when presented with intentional actions in first and third person perspective in a video-clip paradigm. Previous studies have shown that the μ-rhythm is selectively suppressed both when executing and observing goal-directed motor actions; hence it can be used as a neural signal for intentional action processing. Our results show that neutral hypnotic trance increases μ-suppression in highly suggestible participants when they observe intentional actions. This suggests that social action processing is enhanced when bottom-up attentional processes are predominant. Our findings support the Social Relevance Hypothesis, according to which social action processing is a bottom-up driven attentional process, and can thus be altered as a function of bottom-up processing devoted to a social stimulus. PMID:26998562

  3. Quantifying planetary limits of Earth system processes relevant to human activity using a thermodynamic view of the whole Earth system

    NASA Astrophysics Data System (ADS)

    Kleidon, Axel

    2014-05-01

    Food, water, and energy play, obviously, a central role in maintaining human activity. In this contribution, I derive estimates for the fundamental limits on the rates by which these resources are provided by Earth system processes and the levels at which these can be used sustainably. The key idea here is that these resources are, directly or indirectly, generated out of the energy associated with the absorption of sunlight, and that the energy conversions from sunlight to other forms ultimately limit the generation of these resources. In order to derive these conversion limits, we need to trace the links between the processes that generate food, water and energy to the absorption of sunlight. The resource "food" results from biomass production by photosynthesis, which requires light and a sufficient magnitude of gas exchange of carbon dioxide at the surface, which is maintained by atmospheric motion which in turn is generated out of differential radiative heating and cooling. The resource "water" is linked to hydrologic cycling, with its magnitude being linked to the latent heat flux of the surface energy balance and water vapor transport in the atmosphere which is also driven by differential radiative heating and cooling. The availability of (renewable) energy is directly related to the generation of different forms of energy of climate system processes, such as the kinetic energy of atmospheric motion, which, again, relates to radiative heating differences. I use thermodynamics and its limits as a basis to establish the planetary limits of these processes and use a simple model to derive first-order estimates. These estimates compare quite well with observations, suggesting that this thermodynamic view of the whole Earth system provides an objective, physical basis to define and quantify planetary boundaries as well as the factors that shape these boundaries.

  4. Summing NaI(Tl) detector (SuN) for radioactive beam experiments relevant for the p-process

    NASA Astrophysics Data System (ADS)

    Simon, Anna; Beskin, Ilya; Liddick, Sean; Padmanabhan, Karthik; Peace, Jessica; Quinn, Stephen; Spyrou, Artemis; Stefanek, Benjamin

    2011-10-01

    P-process refers to (γ,p), (γ, α) and (γ,n) reactions producing nuclei on the neutron-deficient side of the valley of stability that cannot be reached by s- and r-processes. This process can be investigated via inversed reactions, i.e. proton or alpha capture with gamma emission. Gamma spectra resulting from capture reactions, may be complicated in structure and as such difficult to analyze. However, this difficulty may be omitted by implementing a summing technique, for which all gamma rays emitted during the decay cascade are summed into one peak, so called ``sum peak.'' Thus, in ideal case, the resulting spectrum will comprise of one peak of the energy E = Ecm+Q. This technique has already been successfully tested during stable beam experiments. In order to apply this technique to radioactive beam experiments a new Summing NaI(Tl) (SuN) detector was designed at NSCL. It is a 16x16 inch cylindrical barrel divided into eight optically separated segments, each of them read by three photomultipliers. Each of the PMTs is read independently by a digital data acquisition system (DDAS) and the final sum spectrum is obtained by software summing of the individual spectra. Here, first results obtained with the SuN detector as well as its possible future applications will be presented.

  5. Workshop on Evolution of Igneous Asteroids: Focus on Vesta and the HED Meteorites. Pt. 1

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W. (Editor); Papike, James J. (Editor)

    1996-01-01

    This volume contains abstracts of papers that have been accepted for presentation at the Workshop on Evolution of Igneous Asteroids: Focus on Vesta and the HED Meteorites, October 16-18, 1996, in Houston, Texas.

  6. Recrystallized Impact Glasses of the Onaping Formation and the Sudbury Igneous Complex, Sudbury Structure, Ontario, Canada

    NASA Technical Reports Server (NTRS)

    Dressler, B. O.; Weiser, T.; Brockmeyer, P.

    1996-01-01

    The origin of the Sudbury Structure and of the associated heterolithic breccias of the Onaping Formation and the Sudbury Igneous Complex have been controversial. While an impact origin of the structure has gained wide acceptance over the last 15 years, the origin of the recrystallized Onaping Formation glasses and of the igneous complex is still being debated. Recently the interpretation of the breccias of the Onaping Formation as suevitic fall-back impact breccias has been challenged. The igneous complex is interpreted either as a differentiated impact melt sheet or as a combination of an upper impact melt represented by the granophyre, and a lower, impact-triggered magmatic body consisting of the norite-sublayer formations. The Onaping Formation contains glasses as fluidal and nonfluidal fragments of various shapes and sizes. They are recrystallized, and our research indicates that they are petrographically heterogeneous and span a wide range of chemical compositions. These characteristics are not known from glasses of volcanic deposits. This suggests an origin by shock vitrification, an interpretation consistent with their association with numerous and varied country rock clasts that exhibit microscopic shock metamorphic features. The recrystallized glass fragments represent individual solid-state and liquid-state vitrified rocks or relatively small melt pods. The basal member lies beneath the Gray and Black members of the Onaping Formation and, where not metamorphic, has an igneous matrix. Igneous-textured melt bodies occur in the upper two members and above the Basal Member. A comparison of the chemical compositions of recrystallized glasses and of the matrices of the Basal Member and the melt bodies with the components and the bulk composition of the igneous complex is inconclusive as to the origin of the igneous complex. Basal Member matrix and Melt Bodies, on average, are chemically similar to the granophyre of the Sudbury Igneous Complex, suggesting that

  7. Modeling pCO{sub 2} in the upper ocean: A review of relevant physical, chemical, and biological processes

    SciTech Connect

    1990-12-01

    The pCO{sub 2} of the surface ocean is controlled by a combination of physical, chemical, and biological processes. Modeling surface ocean pCO{sub 2} is analogous to modeling sea surface temperature (SST), in that sea surface pCO{sub 2} is affected by fluxes across the air-sea interface and by exchange with deeper water. However, pCO{sub 2} is also affected by chemical and biological processes which have no analog in SST. Seawater pCO{sub 2} is buffered by pH equilibrium reactions between the species CO{sub 2}, HCO{sub 3}-, and CO{sub 3}{sup =}. This effect provides an effective reservoir for CO{sub 2} in seawater that is 10 times larger than it would be for an unbuffered gas. The equilibrium between dissolved and atmospheric CO{sub 2} is sensitive to temperature, tending to higher pCO{sub 2} in warmer water. Biological export of carbon as sinking particles maintains a gradient of pCO{sub 2}, with lower values near the surface (this processes is called the {open_quotes}biological pump{close_quotes}). In most of the ocean, biological activity removes all of the available nutrients from the surface water; that is, the rate of carbon export in these locations is limited by the rate of nutrient supply to the euphotic zone. However, in much of the high-latitude oceans, primary production does not deplete the euphotic zone of nutrients, a fact to which the atmospheric pCO{sub 2} is extraordinarily sensitive. Understanding the limits to phytoplankton growth in the high latitudes, and how these limits might change under different climatic regimes, is essential to prediction of future ocean uptake of fossil fuel CO{sub 2}.

  8. Attention effects on the processing of task-relevant and task-irrelevant speech sounds and letters

    PubMed Central

    Mittag, Maria; Inauri, Karina; Huovilainen, Tatu; Leminen, Miika; Salo, Emma; Rinne, Teemu; Kujala, Teija; Alho, Kimmo

    2013-01-01

    We used event-related brain potentials (ERPs) to study effects of selective attention on the processing of attended and unattended spoken syllables and letters. Participants were presented with syllables randomly occurring in the left or right ear and spoken by different voices and with a concurrent foveal stream of consonant letters written in darker or lighter fonts. During auditory phonological (AP) and non-phonological tasks, they responded to syllables in a designated ear starting with a vowel and spoken by female voices, respectively. These syllables occurred infrequently among standard syllables starting with a consonant and spoken by male voices. During visual phonological and non-phonological tasks, they responded to consonant letters with names starting with a vowel and to letters written in dark fonts, respectively. These letters occurred infrequently among standard letters with names starting with a consonant and written in light fonts. To examine genuine effects of attention and task on ERPs not overlapped by ERPs associated with target processing or deviance detection, these effects were studied only in ERPs to auditory and visual standards. During selective listening to syllables in a designated ear, ERPs to the attended syllables were negatively displaced during both phonological and non-phonological auditory tasks. Selective attention to letters elicited an early negative displacement and a subsequent positive displacement (Pd) of ERPs to attended letters being larger during the visual phonological than non-phonological task suggesting a higher demand for attention during the visual phonological task. Active suppression of unattended speech during the AP and non-phonological tasks and during the visual phonological tasks was suggested by a rejection positivity (RP) to unattended syllables. We also found evidence for suppression of the processing of task-irrelevant visual stimuli in visual ERPs during auditory tasks involving left-ear syllables

  9. Chemical weathering on Mars - Thermodynamic stabilities of primary minerals /and their alteration products/ from mafic igneous rocks

    NASA Technical Reports Server (NTRS)

    Gooding, J. L.

    1978-01-01

    Chemical weathering on Mars is examined theoretically from the standpoint of thermodynamic equilibrium between primary rock-forming minerals and the atmospheric gases O2, H2O, and CO2. The primary minerals considered are those common to mafic igneous rocks and include olivine, pyroxene, plagioclase, magnetite, troilite, pyrrhotite, and apatite. The importance of kinetics and reaction mechanisms in controlling possible weathering processes on Mars is discussed within the limits of currently available data, and the possible influence of liquid water on Martian weathering processes is evaluated where appropriate. For gas-solid weathering of mafic igneous rocks at the Martian surface, it is concluded that upon attainment of thermodynamic equilibrium: (1) oxides and carbonates should dominate the mineral assemblage of weathering products; (2) hematite rather than goethite should be the stable mineral form of Fe (III); (3) FeSO4 or FeSO4.H2O could be the stable weathering product of iron sulfides in the absence of liquid water; and (4) kaolinite is apparently the only clay mineral that should be thermodynamically stable over all ranges of temperature and water-vapor abundance at the Martian surface.

  10. Depletion of nucleus accumbens dopamine leads to impaired reward and aversion processing in mice: Relevance to motivation pathologies.

    PubMed

    Bergamini, Giorgio; Sigrist, Hannes; Ferger, Boris; Singewald, Nicolas; Seifritz, Erich; Pryce, Christopher R

    2016-10-01

    Dopamine (DA) neurotransmission, particularly the ventral tegmental area-nucleus accumbens (VTA-NAcc) projection, underlies reward and aversion processing, and deficient DA function could underlie motivational impairments in psychiatric disorders. 6-hydroxydopamine (6-OHDA) injection is an established method for chronic DA depletion, principally applied in rat to study NAcc DA regulation of reward motivation. Given the increasing focus on studying environmental and genetic regulation of DA function in mouse models, it is important to establish the effects of 6-OHDA DA depletion in mice, in terms of reward and aversion processing. This mouse study investigated effects of 6-OHDA-induced NAcc DA depletion using the operant behavioural test battery of progressive ratio schedule (PRS), learned non-reward (LNR), learned helplessness (LH), treadmill, and in addition Pavlovian fear conditioning. 6-OHDA NAcc DA depletion, confirmed by ex vivo HPLC-ED, reduced operant responding: for gustatory reward under effortful conditions in the PRS test; to a stimulus recently associated with gustatory non-reward in the LNR test; to escape footshock recently experienced as uncontrollable in the LH test; and to avoid footshock by physical effort in the treadmill test. Evidence for specificity of effects to NAcc DA was provided by lack of effect of medial prefrontal cortex DA depletion in the LNR and LH tests. These findings add significantly to the evidence that NAcc DA is a major regulator of behavioural responding, particularly at the motivational level, to both reward and aversion. They demonstrate the suitability of mouse models for translational study of causation and reversal of pathophysiological DA function underlying motivation psychopathologies. PMID:27036890

  11. Dependence of the drizzle growth process on the cloud top height and its relevance to the aerosol vertical profile

    NASA Astrophysics Data System (ADS)

    Kawamoto, K.; Suzuki, K.

    2013-12-01

    Transitional processes among cloud droplets, drizzle and raindrops are still uncertain and more efforts are required for the better understanding. In this situation, difference in the drizzle growth process was examined according to the cloud top height using the CloudSat and MODIS synergetic datasets. From the CloudSat products such as 2B-GEOPROF, 2B-TAU, ECMWF-AUX, only one-layered water clouds whose top temperatures were warmer than 273K were extracted over China (a circular area having a diameter of 1800km of the center at 35°N and 120°E) and over ocean (a circular area having a diameter of 1500km of the center at 35°N and 150°E). Then a threshold of 3km of the cloud top height was adopted to divide the extracted clouds into upper and lower cases. First, the probability distribution functions (PDF) of the cloud droplet number density (Nc) and the effective particle radius (Re) were calculated for these four cases (land/ocean/upper/lower). Nc was obtained assuming the adiabatic liquid water content from MODIS-derived cloud optical depth and Re. Oceanic clouds had fewer Nc than land clouds, and almost the same for upper and lower cases. Land clouds had more Nc for the lower case than for the higher case. On the other hand, oceanic clouds had larger Re than land clouds, and almost the same for upper and lower cases. Land clouds had smaller Re for the lower case than for the higher case. These results quite agreed with our existing knowledge on the vertical profile of the aerosol number concentration over ocean (pristine) and land (polluted). Although the number of aerosol particles is fewer and almost the same regardless of the height over the ocean, it is more near the surface and it rapidly decreases according to the height over the land. Next, examining PDF of the radar reflectivity (Ze), we found that although PDFs of Ze were almost the same for oceanic clouds regardless of the cloud top height, PDF of land lower clouds were less frequent at around from

  12. Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

    SciTech Connect

    F. Perry; R. Youngs

    2004-10-14

    The purpose of this scientific analysis report is threefold: (1) Present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the probabilistic volcanic hazard analysis (PVHA) (CRWMS M&O 1996 [DIRS 100116]). Conceptual models presented in the PVHA are summarized and applied in areas in which new information has been presented. Alternative conceptual models are discussed, as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) Present revised probability calculations based on PVHA outputs for a repository footprint proposed in 2003 (BSC 2003 [DIRS 162289]), rather than the footprint used at the time of the PVHA. This analysis report also calculates the probability of an eruptive center(s) forming within the repository footprint using information developed in the PVHA. Probability distributions are presented for the length and orientation of volcanic dikes located within the repository footprint and for the number of eruptive centers (conditional on a dike intersecting the repository) located within the repository footprint. (3) Document sensitivity studies that analyze how the presence of potentially buried basaltic volcanoes may affect the computed frequency of intersection of the repository footprint by a basaltic dike. These sensitivity studies are prompted by aeromagnetic data collected in 1999, indicating the possible presence of previously unrecognized buried volcanoes in the YMR (Blakely et al. 2000 [DIRS 151881]; O'Leary et al. 2002 [DIRS 158468]). The results of the sensitivity studies are for informational purposes only and are not to be used for purposes of assessing repository performance.

  13. Thermal conductivity anisotropy of metasedimentary and igneous rocks

    NASA Astrophysics Data System (ADS)

    Davis, Michael G.; Chapman, David S.; van Wagoner, Thomas M.; Armstrong, Phillip A.

    2007-05-01

    Thermal conductivity anisotropy was determined for three sets of metasedimentary and igneous rocks from central Utah, USA. Most conductivity measurements were made in transient mode with a half-space, line source instrument oriented in two orthogonal directions on a flat face cut perpendicular to bedding. One orientation of the probe yields thermal conductivity parallel to bedding (kpar) directly, the other orientation of the probe measures a product of conductivities parallel and perpendicular to bedding from which the perpendicular conductivity (kperp) is calculated. Some direct measurements of kpar and kperp were made on oriented cylindrical discs using a conventional divided bar device in steady state mode. Anisotropy is defined as kpar/kperp. Precambrian argillites from Big Cottonwood Canyon have anisotropy values from 0.8 to 2.1 with corresponding conductivity perpendicular to bedding of 2.0 to 6.2 W m-1 K-1. Anisotropy values for Price Canyon sedimentary samples are less than 1.2 with a mean of 1.04 although thermal conductivity perpendicular to bedding for the samples varied from 1.3 to 5.0 W m-1 K-1. The granitic rocks were found to be essentially isotropic with thermal conductivity perpendicular to bedding having a range of 2.2 to 3.2 W m-1 K-1 and a mean of 2.68 W m-1 K-1. The results confirm the observation by Deming [1994] that anisotropy is negligible for rocks having kperp greater than 4.0 W m-1 K-1 and generally increases for low conductivity metamorphic and clay-rich rocks. There is little evidence, however, for his suggestion that thermal conductivity anisotropy of all rocks increases systematically to about 2.5 for low thermal conductivity rocks.

  14. Roots of Magmatic Systems of Large Continental Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Sharkov, E. V.

    2014-12-01

    It is consensus now that appearance of the large igneous provinces (LIP) is considered with ascending of mantle superplumes. It is evident that beneath LIPs was not exited magma oceans and adiabatic melting occurred in heads of protuberances on their surface (local, or secondary plumes), which can reach relatively shallow levels. The least known element of magmatic system is area of magma generation and meltedsources. Important information about it is contained in the mantle xenoliths in alkali basalts. They are represented by two series: (1) "green": spinel peridotite (maily lherzolite) and minor spinel pyroxenite (websterite), and (2) "black" (veins in the peridotite matrix): wehrlite, Al-Ti-augite and hornblende clinopyroxenite, hornblendite, phlogopitite, etc, which crystallized from fluid-saturated melts or high-density fluid. Very likely, that these fluids, enriched in Fe, Ti, alkalis and incompatible elements, were parts of intergranular material of original plume material and were released due to its decompression; evidently, they provided specific composition of plume-related melts. Both types of xenoliths represent material of plume head and accordingly - the melting substratum. One of problem of plume-related magmatism is coexisting of alkali and tholeiitic basalts, which origin often considered with different PT conditions. However, this situation can be explained another way. Because fluid components, acting jointly or separately, impregnated the peridotite matrix nonuniform, it led to heterogeneous composition of smelted magmas, and primary melts can have different composition even though be forming at similar PT conditions. According to Yoder and Tilley (1962), even small differences in SiO2 content lead to different ways in evolution of magmas due to critical plane of silica undersaturation. As a result, one magmas will develop to Ne enrichment (alkali basalts) and another - to silica direction (tholeiite basalts.

  15. Linking mantle plumes, large igneous provinces and environmental catastrophes.

    PubMed

    Sobolev, Stephan V; Sobolev, Alexander V; Kuzmin, Dmitry V; Krivolutskaya, Nadezhda A; Petrunin, Alexey G; Arndt, Nicholas T; Radko, Viktor A; Vasiliev, Yuri R

    2011-09-15

    Large igneous provinces (LIPs) are known for their rapid production of enormous volumes of magma (up to several million cubic kilometres in less than a million years), for marked thinning of the lithosphere, often ending with a continental break-up, and for their links to global environmental catastrophes. Despite the importance of LIPs, controversy surrounds even the basic idea that they form through melting in the heads of thermal mantle plumes. The Permo-Triassic Siberian Traps--the type example and the largest continental LIP--is located on thick cratonic lithosphere and was synchronous with the largest known mass-extinction event. However, there is no evidence of pre-magmatic uplift or of a large lithospheric stretching, as predicted above a plume head. Moreover, estimates of magmatic CO(2) degassing from the Siberian Traps are considered insufficient to trigger climatic crises, leading to the hypothesis that the release of thermogenic gases from the sediment pile caused the mass extinction. Here we present petrological evidence for a large amount (15 wt%) of dense recycled oceanic crust in the head of the plume and develop a thermomechanical model that predicts no pre-magmatic uplift and requires no lithospheric extension. The model implies extensive plume melting and heterogeneous erosion of the thick cratonic lithosphere over the course of a few hundred thousand years. The model suggests that massive degassing of CO(2) and HCl, mostly from the recycled crust in the plume head, could alone trigger a mass extinction and predicts it happening before the main volcanic phase, in agreement with stratigraphic and geochronological data for the Siberian Traps and other LIPs. PMID:21921914

  16. Spatial distribution analysis of igneous textures: Numerical modeling and interpretation of crystal accumulation in plutons

    NASA Astrophysics Data System (ADS)

    Špillar, Václav; Dolejš, David

    2014-05-01

    Magma differentiation by fractionation of crystals from their parental liquids is central to igneous petrogenesis and it has been thoroughly documented by geochemical studies on the suites of cogenetic magmatic rocks. In spite of this, physical nature of the fractionation process remains poorly understood as are consequences of crystal-liquid separation for quantitative interpretation of igneous textures. We have developed a new Monte Carlo numerical model that simulates texture evolution during accumulation of crystals or extraction of melt from the crystal-liquid assembly. As the input parameters, the model utilizes three-dimensional configuration of crystal centers resulting from dynamic crystallization terminated at predefined crystallinity level. To simulate the melt extraction, the configuration is packed randomly into progressively decreasing volume and this process is repeated to obtain ensemble averages. To facilitate the interpretation of natural sections or outcrop patterns, predicted three-dimensional textures are cut by two-dimensional sections where we analyze the spatial distribution pattern of crystal centers using the clustering index and the radial distribution function. In contrast to the closed-system crystallization, progressive accumulation of crystals (or extraction of interstitial melt) induces increasing ordering, that is, anti-clustering of crystals. These effects result from finite sizes of individual crystals in the time of accumulation that thus cannot approach each other closer than is the sum of their respective sizes. To apply the new approach, we have measured spatial distribution patterns of alkali feldspar megacrysts in the Jizera granite of the Krkonoše-Jizera batholith in central Europe. The granite is porphyritic, biotite-rich, with ~10 to 25 % of alkali feldspar megacrysts. The observed textural patterns suggest the extraction of ~15 to 70 % melt from the original crystal mush prior to its solidification, reflecting a

  17. Metamorphic and thermal evolution of large contact aureoles - lessons from the Bushveld Igneous Complex

    NASA Astrophysics Data System (ADS)

    Waters, D.

    2012-04-01

    Large igneous intrusions crystallise, cool, and transfer heat out into their host rocks. The thermal structure of the resulting aureole can be mapped as a series of assemblage zones and isograds, and can in principle be modelled on the assumption that heat transfer is dominantly by conduction. The local peak of contact metamorphism occurs later in time with increasing distance from the igneous contact. The importance of fluids as a metamorphic/metasomatic agent or heat transfer mechanism depends on volatile contents of magma and country rock, and on the geometry of the intrusion. Many of these features are spectacularly illustrated by the aureole beneath the mafic Rustenburg Layered Suite of the Bushveld Complex, which was emplaced at ca. 2060 Ma sub-concordantly into the shale-quartzite succession of the Pretoria Group in the Transvaal Basin. The layered suite reaches a thickness of at least 8 km, and the metamorphic aureole extends 4 km or more downwards into the "floor" of the intrusion. The great extent and relative absence of deformation make this a remarkable natural laboratory for studying the fundamental processes of metamorphism. In quantifying the thermal history, however, a number of second-order factors need to be taken into account. The first relates to the markedly different thermal properties of the major quartzite and shale units, and the second to the importance of endothermic metamorphic reactions in shale units relative to the quartzites. Further insights into metamorphic processes arise from the exquisite detail of poikiloblast growth microstructures preserved in graphite-poor metapelites of the Timeball Hill and Silverton Formations, 2.5 to 3.5 km beneath the igneous contact. These allow a detailed reconstruction of the time sequence of mineral growth and replacement, revealing a marked overlap of the growth intervals of porphyroblastic staurolite, cordierite, biotite, garnet and andalusite at the expense of muscovite, chlorite and chloritoid

  18. Modeling the Interaction between Quinolinate and the Receptor for Advanced Glycation End Products (RAGE): Relevance for Early Neuropathological Processes

    PubMed Central

    Serratos, Iris N.; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Reyes-Espinosa, Francisco; Díaz-Garrido, Paulina; López-Macay, Ambar; Martínez-Flores, Karina; López-Reyes, Alberto; Sánchez-García, Aurora; Cuevas, Elvis; Santamaria, Abel

    2015-01-01

    The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function. PMID:25757085

  19. Perceived parenting dimensions and identity styles: exploring the socialization of adolescents' processing of identity-relevant information.

    PubMed

    Smits, Ilse; Soenens, Bart; Luyckx, Koen; Duriez, Bart; Berzonsky, Michael; Goossens, Luc

    2008-04-01

    This study examined the relationships between crucial dimensions of perceived parenting (support, behavioral control, and psychological control) and the three identity styles defined by Berzonsky [Berzonsky, M. D. (1990). Self-construction over the life span: A process perspective on identity formation. Advances in Personal Construct Psychology, 1, 155-186.]. Each identity style was hypothesized to relate to a specific pattern of perceived parenting dimensions. Hypotheses were examined in a sample of middle and late adolescents (n=674). An information-oriented style was positively predicted by parental support. Contrary to expectations, however, an information-oriented style was also positively predicted by psychological control. A normative identity style was positively predicted by support and behavioral control. In line with expectations, a diffuse-avoidant identity style was positively predicted by psychological control and negatively by maternal (but not paternal) behavioral control. Findings are discussed in light of the literature on the socialization of identity formation and directions for future research are outlined. PMID:18423253

  20. Endothelial repair process and its relevance to longitudinal neointimal tissue patterns: comparing histology with in silico modelling

    PubMed Central

    Tahir, Hannan; Bona-Casas, Carles; Narracott, Andrew James; Iqbal, Javaid; Gunn, Julian; Lawford, Patricia; Hoekstra, Alfons G.

    2014-01-01

    Re-establishing a functional endothelium following endovascular treatment is an important factor in arresting neointimal proliferation. In this study, both histology (in vivo) and computational simulations (in silico) are used to evaluate neointimal growth patterns within coronary arteries along the axial direction of the stent. Comparison of the growth configurations in vivo and in silico was undertaken to identify candidate mechanisms for endothelial repair. Stent, lumen and neointimal areas were measured from histological sections obtained from eight right coronary stented porcine arteries. Two re-endothelialization scenarios (endothelial cell (EC) random seeding and EC growth from proximal and distal ends) were implemented in silico to evaluate their influence on the morphology of the simulated lesions. Subject to the assumptions made in the current simulations, comparison between in vivo and in silico results suggests that endothelial growth does not occur from the proximal and distal ends alone, but is more consistent with the assumption of a random seeding process. This may occur either from the patches of endothelium which survive following stent implantation or from attachment of circulating endothelial progenitor cells. PMID:24621816

  1. Modeling the interaction between quinolinate and the receptor for advanced glycation end products (RAGE): relevance for early neuropathological processes.

    PubMed

    Serratos, Iris N; Castellanos, Pilar; Pastor, Nina; Millán-Pacheco, César; Rembao, Daniel; Pérez-Montfort, Ruy; Cabrera, Nallely; Reyes-Espinosa, Francisco; Díaz-Garrido, Paulina; López-Macay, Ambar; Martínez-Flores, Karina; López-Reyes, Alberto; Sánchez-García, Aurora; Cuevas, Elvis; Santamaria, Abel

    2015-01-01

    The receptor for advanced glycation end products (RAGE) is a pattern-recognition receptor involved in neurodegenerative and inflammatory disorders. RAGE induces cellular signaling upon binding to a variety of ligands. Evidence suggests that RAGE up-regulation is involved in quinolinate (QUIN)-induced toxicity. We investigated the QUIN-induced toxic events associated with early noxious responses, which might be linked to signaling cascades leading to cell death. The extent of early cellular damage caused by this receptor in the rat striatum was characterized by image processing methods. To document the direct interaction between QUIN and RAGE, we determined the binding constant (Kb) of RAGE (VC1 domain) with QUIN through a fluorescence assay. We modeled possible binding sites of QUIN to the VC1 domain for both rat and human RAGE. QUIN was found to bind at multiple sites to the VC1 dimer, each leading to particular mechanistic scenarios for the signaling evoked by QUIN binding, some of which directly alter RAGE oligomerization. This work contributes to the understanding of the phenomenon of RAGE-QUIN recognition, leading to the modulation of RAGE function. PMID:25757085

  2. Improvement of toughness and electrical properties of epoxy composites with carbon nanotubes prepared by industrially relevant processes.

    PubMed

    Hollertz, R; Chatterjee, S; Gutmann, H; Geiger, T; Nüesch, F A; Chu, B T T

    2011-03-25

    The addition of carbon nanotubes (CNTs) to polymeric matrices or master batches has the potential to provide composites with novel properties. However, composites with a uniform dispersion of CNTs have proved to be difficult to manufacture, especially at an industrial scale. This paper reports on processing methods that overcome problems related to the control and reproducibility of dispersions. By using a high pressure homogenizer and a three-roll calendaring mill in combination, CNT reinforced epoxies were fabricated by mould casting with a well dispersed nanofiller content from 0.1 to 2 wt%. The influence of the nano-carbon reinforcements on toughness and electrical properties of the CNT/epoxies was studied. A substantial increase of all mechanical properties already appeared at the lowest CNT content of 0.1 wt%, but further raising the nanofiller concentration only led to moderate further changes. The most significant enhancement was obtained for fracture toughness, reaching up to 82%. The low percolation thresholds were confirmed by electrical conductivity measurements on the same composites yielding a threshold value of only about 0.01 wt%. As corroborated by a thorough microscopic analysis of the composites, mechanical and electrical enhancement points to the formation of an interconnected network of agglomerated CNTs. PMID:21317490

  3. Simulation of reaction diffusion processes over biologically relevant size and time scales using multi-GPU workstations

    PubMed Central

    Hallock, Michael J.; Stone, John E.; Roberts, Elijah; Fry, Corey; Luthey-Schulten, Zaida

    2014-01-01

    Simulation of in vivo cellular processes with the reaction-diffusion master equation (RDME) is a computationally expensive task. Our previous software enabled simulation of inhomogeneous biochemical systems for small bacteria over long time scales using the MPD-RDME method on a single GPU. Simulations of larger eukaryotic systems exceed the on-board memory capacity of individual GPUs, and long time simulations of modest-sized cells such as yeast are impractical on a single GPU. We present a new multi-GPU parallel implementation of the MPD-RDME method based on a spatial decomposition approach that supports dynamic load balancing for workstations containing GPUs of varying performance and memory capacity. We take advantage of high-performance features of CUDA for peer-to-peer GPU memory transfers and evaluate the performance of our algorithms on state-of-the-art GPU devices. We present parallel e ciency and performance results for simulations using multiple GPUs as system size, particle counts, and number of reactions grow. We also demonstrate multi-GPU performance in simulations of the Min protein system in E. coli. Moreover, our multi-GPU decomposition and load balancing approach can be generalized to other lattice-based problems. PMID:24882911

  4. Homologous expression and biochemical characterization of the arylsulfatase from Kluyveromyces lactis and its relevance in milk processing.

    PubMed

    Stressler, Timo; Leisibach, Desirée; Lutz-Wahl, Sabine; Kuhn, Andreas; Fischer, Lutz

    2016-06-01

    The industrial manufacturing process of lactose-free milk products depends on the application of commercial β-galactosidase (lactase) preparations. These preparations are often obtained from Kluyveromyces lactis. There is a gene present in the genome of K. lactis which should encode for an enzyme called arylsulfatase (EC 3.1.6.1). Therefore, this enzyme could also be present in β-galactosidase preparations. The arylsulfatase is suspected of being responsible for an unpleasant "cowshed-like" off-flavor resulting from the release of p-cresol from milk endogenous alkylphenol sulfuric esters. So far, no gene/functionality relationship is described. In addition, no study is available which has shown that arylsulfatase from K. lactis is truly responsible for the flavor generation. In this study, we cloned the putative arylsulfatase gene from K. lactis GG799 into the commercially available vector pKLAC2. The cloning strategy chosen resulted in a homologous, secretory expression of the arylsulfatase. We showed that the heretofore putative arylsulfatase has the desired activity with the synthetic substrate p-nitrophenyl sulfate and with the natural substrate p-cresol sulfate. The enzyme was biochemically characterized and showed an optimum temperature of 45-50 °C and an optimum pH of 9-10. Additionally, the arylsulfatase was activated by Ca(2+) ions and was inactivated by Zn(2+) ions. Moreover, the arylsulfatase was inhibited by p-cresol and sulfate ions. Finally, the enzyme was added to ultra-heat treated (UHT) milk and a sensory triangle test verified that the arylsulfatase from K. lactis can cause an unpleasant "cowshed-like" off-flavor. PMID:26875879

  5. Chemical Potential of Triethylene Glycol Adsorbed on Surfaces Relevant to Gas Transport and Processing - Studies Using Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Kvamme, B.; Olsen, R.; Sjöblom, S.; Leirvik, K. N.; Kuznetsova, T.

    2014-12-01

    Natural gas will inevitably contain trace amounts of water and other impurities during different stages of processing and transport. Glycols, such as triethylene glycol (TEG), will in many cases follow the water. The glycol contents of the gas can originate from preceding glycol-drying units or it can be a residue from the direct injection of glycols used to prevent hydrate formation. Thus, it is important to know how glycol contents will affect the different paths leading to hydrate formation. Glycols may in some cases dominate the condensed water phase. If this occurs, it will lead to the well-documented shift in the hydrate stability curve, due to the altered activity of the water. A great deal of information on the molecular path of a glycol through the system can be obtained from calculating the chemical potential. Due to difficulties in measuring interfacial chemical potentials, these often need to be estimated using theoretical tools. We used molecular dynamics (MD) to study how TEG behaves in the vicinity of mineral surfaces such as calcite and hematite. Many methods exist for estimating chemical potentials based on MD trajectories. These include techniques such as free energy perturbation theory (FEP) and thermodynamic integration (TI). Such methods require sufficient sampling of configurations where free energy is to be estimated. Thus, it can be difficult to estimate chemical potentials on surfaces. There are several methods to circumvent this problem, such as blue moon sampling and umbrella sampling. These have been considered and the most important have been used to estimate chemical potentials of TEG adsorbed on the mineral surfaces. The resulting chemical potentials were compared to the chemical potential of TEG in bulk water, which was estimated using temperature thermodynamic integration.

  6. Theoretical uncertainty of (α ,n ) reactions relevant for the nucleosynthesis of light r -process nuclei in neutrino-driven winds

    NASA Astrophysics Data System (ADS)

    Pereira, J.; Montes, F.

    2016-03-01

    Background: Neutrino-driven winds following core-collapse supernova explosions have been proposed as a possible site where light r -process nuclei (between Fe and Ag) might be synthesized. In these events, (α ,n ) reactions are key to moving matter towards the region of higher proton number. Abundance network calculations are very sensitive to the rates for this type of reactions. Purpose: The present work aims at evaluating the theoretical uncertainty of these (α ,n ) reactions calculated with reaction codes based on the Hauser-Feshbach model. Method: We compared several (α ,n ) rates taken from talys and the non-smoker database to determine the uncertainties owing to the existing technical differences between both codes. In addition, we evaluated the sensitivity of talys rates to variations in the α optical potentials, masses, level densities, optical potentials, preequilibrium intranuclear transition rates, level structure, radiative transmission coefficients, and width-fluctuation correction factors. Results: The main source of uncertainty at low temperature is mostly attributable to the use of different α optical potentials. Differences between talys and non-smoker at high temperatures arise from the energy-binning algorithm used by each code. We have also noticed that the (α ,n ) rates from the non-smoker database correspond to the inclusive reaction, instead of the exclusive (α ,1 n ) channel calculated in the present work and used in network calculations. Conclusions: Theoretical uncertainties in calculated reaction rates can be as high as one to two orders of magnitude and strongly dependent on the temperature of the environment. Besides direct measurements of the inclusive and exclusive (α ,1 n ) reaction rates, experimental studies of α optical potentials are crucial to improve the performance of reaction codes.

  7. The seven-transmembrane receptor Gpr1 governs processes relevant for the antagonistic interaction of Trichoderma atroviride with its host.

    PubMed

    Omann, Markus R; Lehner, Sylvia; Escobar Rodríguez, Carolina; Brunner, Kurt; Zeilinger, Susanne

    2012-01-01

    Mycoparasitic Trichoderma species are applied as biocontrol agents in agriculture to guard plants against fungal diseases. During mycoparasitism, Trichoderma directly interacts with phytopathogenic fungi, preceded by a specific recognition of the host and resulting in its disarming and killing. In various fungal pathogens, including mycoparasites, signalling via heterotrimeric G proteins plays a major role in regulating pathogenicity-related functions. However, the corresponding receptors involved in the recognition of host-derived signals are largely unknown. Functional characterization of Trichoderma atroviride Gpr1 revealed a prominent role of this seven-transmembrane protein of the cAMP-receptor-like family of fungal G-protein-coupled receptors in the antagonistic interaction with the host fungus and governing of mycoparasitism-related processes. Silencing of gpr1 led to an avirulent phenotype accompanied by an inability to attach to host hyphae. Furthermore, gpr1-silenced transformants were unable to respond to the presence of living host fungi with the expression of chitinase- and protease-encoding genes. Addition of exogenous cAMP was able to restore host attachment in gpr1-silenced transformants but could not restore mycoparasitic overgrowth. A search for downstream targets of the signalling pathway(s) involving Gpr1 resulted in the isolation of genes encoding e.g. a member of the cyclin-like superfamily and a small secreted cysteine-rich protein. Although silencing of gpr1 caused defects similar to those of mutants lacking the Tga3 Gα protein, no direct interaction between Gpr1 and Tga3 was observed in a split-ubiquitin two-hybrid assay. PMID:22075023

  8. Rearrangement of stresses in fault zones - detecting major issues of coupled hydraulic-mechanical processes with relevance to geothermal applications

    NASA Astrophysics Data System (ADS)

    Ziefle, G.

    2014-09-01

    The South German Molasse Basin provides favourable conditions for geothermal plants. Nevertheless, micro-seismic events occur in the vicinity of the geothermal Unterhaching Gt2 well and seem to be caused by the geothermal plant. The injection and production are located in an existing fault system. The majority of seismic events takes place at a horizontal distance of 500 m or less of the borehole. However, none of the seismic events are located in the injection reservoir but in fact at a significantly greater depth. A deeper process understanding of the interacting thermal-hydraulic-mechanical effects in the vicinity of the well is desired. This article presents a significantly simplified 2-D model, investigating interactions of the stress field in the vicinity of the geothermal well and movements in the fault system. This might be of special interest, as the operation of the geothermal plant might lead to changes in the material and fracture properties on the one hand and in the equilibrium state on the other. A detailed description of the model, as well as various parameter studies, is presented. It can be seen that boundary conditions such as direction of the stress field in relation to the fault system, geometry of the fault system and parameters of the fractures have a significant influence on stresses in the proximity of the geothermal well. A variation in the spatial stress field in some parts of the fault system is to be expected. For the chosen assumptions the dimension of this variation is about 25% of the assumed stresses. Future work on this model might focus on the characteristics of the fault system, as well as on the influence of the coupled thermal-hydraulic-mechanical effects.

  9. A discussion of isotopic systematics and mineral zoning in the shergottites - Evidence for a 180 m.y. igneous crystallization age

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1986-01-01

    The chronologies of the Shergotty, Zagami, ALHA 77005, and EETA 79001 meteorites were reexamined on the basis of shergottites' petrography and mineral chemistry data. Among the various isochrons, the concordant Rb-Sr (about 180 Myr) and U-Th-Pb (about 190 Myr) internal isochrons are interpreted as representing the time of igneous crystallization, while the Rb-Sr, Sm-Nd, and Pb-Pb whole-rock isochrons are interpreted as mixing lines, and are reasonably attributed to igneous processes such as wall-rock assimilation and magma mixing. If the approximated age of less than 200 Myr is correct, the shergottites represent the youngest known extraterrestrial basalts. This conclusion supports the hypothesis that the SNC meteorites are samples of Mars.

  10. Magmatic underplating beneath the Emeishan large igneous province (South China) revealed by the COMGRA-ELIP experiment

    NASA Astrophysics Data System (ADS)

    Deng, Yangfan; Chen, Yun; Wang, Peng; Essa, Khalid S.; Xu, Tao; Liang, Xiaofeng; Badal, José

    2016-03-01

    Because of the abundant geological, geochemical and geophysical studies conducted on the Emeishan large igneous province (ELIP) in South China, the Permian mantle plume model associated with this region is widely accepted. Furthermore, the dome-shaped structure related with this plume has been determined with success by sedimentological data and gravity stripping. Although the sediment thickness, upper crust, Moho depth and the lithosphere-asthenosphere boundary (LAB) are well constrained by active- and passive-source seismological results, the density anomaly in ELIP is still a poorly constrained issue that needs further attention. With the aim especially to understand the impact on surface of the magmatic processes that originated in the deep mantle, we performed the COMGRA-ELIP gravity experiment across this region. Using a stripping method, we determined the residual gravity in ELIP and surrounding areas. The residual gravity reaches a maximum value of + 150 mGal in the inner zone of ELIP and its strength decreases gradually when measuring from the inner zone to the middle and outer zones. Combining active and passive seismic results and the least-squares variance analysis method, we propose a strong density contrast of 0.2 g/cm3 (density of 3.14 g/cm3) for the 15- to 20-km-thick igneous layer accreted at the base of the crust, as evidence of crustal underplating in ELIP, to explain the present-day residual gravity anomaly.

  11. Igneous geology of the Carlin trend, Nevada: The importance of Eocene magmatism in gold mineralization

    NASA Astrophysics Data System (ADS)

    Ressel, Michael Walter, Jr.

    Igneous rocks of five ages are present in the Carlin trend, Nevada, and include: (1) Paleozoic basalt of the Roberts Mountains allochthon, (2) the Jurassic (˜158 Ma) Goldstrike intrusive complex, which includes the Goldstrike diorite laccolith and abundant dikes and sills, (3) a Cretaceous (112 Ma) granite stock, (4) lavas and intrusions of the Emigrant Pass volcanic field and widespread epizonal plugs and dikes of Eocene (˜40-36 Ma) age that range from rhyolite through basalt, and (5) Miocene (15 Ma) rhyolite lava and tuff. Jurassic and Eocene igneous rocks are by far the most important volumetrically and are spatially associated with nearly all ore deposits of the Carlin trend. This study focuses on the field relations, isotopic dating, and geochemistry of Eocene dikes that intrude sedimentary rocks in many deposits of the Carlin trend, because they are the youngest pre-mineral rocks and have simpler alteration histories than other host rocks. In the Beast, Genesis, Deep Star, Betze-Post, Rodeo-Goldbug, Meikle-Griffin, and Dee-Storm deposits, Eocene dikes are altered, commonly mineralized, and locally constitute ore. Gold-bearing dikes and sedimentary rocks have similar ore mineralogy, including arsenian pyrite, marcasite, and arsenopyrite, with late barite and stibnite. At Beast, as much as half the ore is hosted in a 37.3 Ma rhyolite dike. Post-gold alunite is ˜18.6 Ma. At Meikle and Griffin, porphyritic dacite dikes yield concordant U/Pb zircon and 40Ar/39Ar biotite emplacement ages of ˜39.2 Ma, and illite from the same QSP-altered dacite, with as much 9 ppm Au, yields similar, although imprecise 40Ar/39Ar ages. Thus, gold mineralization at these deposits closely followed emplacement of Eocene dikes. Carlin-type gold deposits in northeastern Nevada have been variously interpreted as partly syngenetic with Paleozoic carbonate rocks, products of Mesozoic contraction and metamorphism with or without significant magmatism, and of Tertiary age and related or

  12. Aspects of igneous activity significant to a repository at Yucca Mountain, Nevada

    SciTech Connect

    Krier, D. J.; Perry, F. V.

    2004-01-01

    Location, timing, volume, and eruptive style of post-Miocene volcanoes have defined the volcanic hazard significant to a proposed high-level radioactive waste (HLW) and spent nuclear fuel (SNF) repository at Yucca Mountain, Nevada, as a low-probability, high-consequence event. Examination of eruptive centers in the region that may be analogueues to possible future volcanic activity at Yucca Mountain have aided in defining and evaluating the consequence scenarios for intrusion into and eruption above a repository. The probability of a future event intersecting a repository at Yucca Mountain has a mean value of 1.7 x 10{sup -8} per year. This probability comes from the Probabilistic Volcanic Hazard Assessment (PVHA) completed in 1996 and updated to reflect change in repository layout. Since that time, magnetic anomalies representing potential buried volcanic centers have been identified fiom magnetic surveys; however these potential buried centers only slightly increase the probability of an event intersecting the repository. The proposed repository will be located in its central portion of Yucca Mountain at approximately 300m depth. The process for assessing performance of a repository at Yucca Mountain has identified two scenarios for igneous activity that, although having a very low probability of occurrence, could have a significant consequence should an igneous event occur. Either a dike swarm intersecting repository drifts containing waste packages, or a volcanic eruption through the repository could result in release of radioactive material to the accessible environment. Ongoing investigations are assessing the mechanisms and significance of the consequence scenarios. Lathrop Wells Cone ({approx}80,000 yrs), a key analogue for estimating potential future volcanic activity, is the youngest surface expression of apparent waning basaltic volcanism in the region. Cone internal structure, lavas, and ash-fall tephra have been examined to estimate eruptive volume

  13. Patterns and origin of igneous activity around the Tanzanian craton

    NASA Astrophysics Data System (ADS)

    Foley, S. F.; Link, K.; Tiberindwa, J. V.; Barifaijo, E.

    2012-01-01

    Tertiary and later igneous activity is common on and around the Tanzanian craton, with primitive magma compositions ranging from kimberlites and varieties of picrites through nephelinites, basanites and alkali basalts. This review focuses on elucidating the conditions of origin of the melts, addressing the question of the state and involvement of the Tanzanian cratonic lithosphere in magma genesis. The Tanzanian craton is anomalous with a surface elevation of >1100 m reflecting buoyancy supported by a subcratonic plume whose effects are seen in the volcanics of both western and eastern rift branches. Magmatism on the craton and at its edge has high K/Na and primitive melts show fractionation dominated by olivine. Slightly further from the craton pyroxene fractionation dominates and K/Na ratios in the magmas are lower. Off-craton melts are nephelinites, basanites and alkali basalts with low K/Na. Potassium enrichment in the melts correlates with the occurrence of phlogopite in mantle-derived xenoliths, and also with carbonate in the magmas. This is attributed to melting at >140 km depths of mixed source regions containing phlogopite pyroxenite and peridotite, whereby the carbonate is derived from oxidation of diamonds concentrated near the base of the cratonic lithosphere. Mixed source regions are required by arrays of radiogenic isotopes such as Os and Sr in the volcanic rocks. The temporal progression of lamproites to phlogopite + carbonate-rich rocks to melilitites, nephelinites and alkali basalts seen during the erosion of the North Atlantic craton are seen around the Tanzanian craton as the coeval occurrence kimberlites, kamafugites and related rocks, nephelinites and alkali basalts showing spatial instead of temporal variation. This is due to the different stages of development of rifting around the craton: in northwestern Uganda and northern Tanzania, K-rich volcanism occurs at the craton edge, whereas nephelinites, basanites and alkali basalts occur where

  14. Time-course of hemispheric preference for processing contralateral relevant shapes: P1pc, N1pc, N2pc, N3pc.

    PubMed

    Verleger, Rolf; Zurawska Vel Grajewska, Blandyna; Jaśkowski, Piotr

    2012-01-01

    A most sensitive and specific electrophysiological indicator of selective processing of visual stimuli is the N2pc component. N2pc is a negative EEG potential peaking 250 ms after stimulus onset, recorded from posterior sites contralateral to relevant stimuli. Additional deflections preceding or following N2pc have been obtained in previous studies, possibly produced by specific stimulus features or specific prime-target sequences. To clarify the entire time-course of the contralateral- ipsilateral (C-I) difference recorded from the scalp above visual cortex in response to left-right pairs of targets and distracters, C-I differences were here compared between two types of stimuli and between stimuli that were or were not preceded by masked neutral primes. The C-I difference waveform consisted of several peaks, termed here P1pc (60-100 ms after target onset), N1pc (120-160 ms), N2pc (220-280 ms), and N3pc (360-400 ms). Being markedly enhanced when stimuli were preceded by the neutral primes, P1pc may indicate a response to stimulus change. Also, when stimuli were primed, N2pc reached its peak earlier, thereby tending to merge with N1pc. N3pc seemed to increase when target discrimination was difficult. N1pc, N2pc, and N3pc appear as three periods of one process. N3pc probably corresponds to L400 or SPCN as described in other studies. These observations suggest that the neurophysiological basis of stimulus-driven focusing of attention on target stimuli is a process that lasts for hundreds of milliseconds, with the relevant hemisphere being activated in an oscillating manner as long as required by the task. PMID:22419963

  15. Time-course of hemispheric preference for processing contralateral relevant shapes: P1pc, N1pc, N2pc, N3pc

    PubMed Central

    Verleger, Rolf; Żurawska vel Grajewska, Blandyna; Jaśkowski, Piotr

    2012-01-01

    A most sensitive and specific electrophysiological indicator of selective processing of visual stimuli is the N2pc component. N2pc is a negative EEG potential peaking 250 ms after stimulus onset, recorded from posterior sites contralateral to relevant stimuli. Additional deflections preceding or following N2pc have been obtained in previous studies, possibly produced by specific stimulus features or specific prime-target sequences. To clarify the entire time-course of the contralateral- ipsilateral (C-I) difference recorded from the scalp above visual cortex in response to left-right pairs of targets and distracters, C-I differences were here compared between two types of stimuli and between stimuli that were or were not preceded by masked neutral primes. The C-I difference waveform consisted of several peaks, termed here P1pc (60-100 ms after target onset), N1pc (120-160 ms), N2pc (220-280 ms), and N3pc (360-400 ms). Being markedly enhanced when stimuli were preceded by the neutral primes, P1pc may indicate a response to stimulus change. Also, when stimuli were primed, N2pc reached its peak earlier, thereby tending to merge with N1pc. N3pc seemed to increase when target discrimination was difficult. N1pc, N2pc, and N3pc appear as three periods of one process. N3pc probably corresponds to L400 or SPCN as described in other studies. These observations suggest that the neurophysiological basis of stimulus-driven focusing of attention on target stimuli is a process that lasts for hundreds of milliseconds, with the relevant hemisphere being activated in an oscillating manner as long as required by the task. PMID:22419963

  16. Adaptation to recent conflict in the classical color-word Stroop-task mainly involves facilitation of processing of task-relevant information.

    PubMed

    Purmann, Sascha; Pollmann, Stefan

    2015-01-01

    To process information selectively and to continuously fine-tune selectivity of information processing are important abilities for successful goal-directed behavior. One phenomenon thought to represent this fine-tuning are conflict adaptation effects in interference tasks, i.e., reduction of interference after an incompatible trial and when incompatible trials are frequent. The neurocognitive mechanisms of these effects are currently only partly understood and results from brainimaging studies so far are mixed. In our study we validate and extend recent findings by examining adaption to recent conflict in the classical Stroop task using functional magnetic resonance imaging. Consistent with previous research we found increased activity in a fronto-parietal network comprising the medial prefrontal cortex, ventro-lateral prefrontal cortex, and posterior parietal cortex when contrasting incompatible with compatible trials. These areas have been associated with attentional processes and might reflect increased cognitive conflict and resolution thereof during incompatible trials. While carefully controlling for non-attentional sequential effects we found smaller Stroop interference after an incompatible trial (conflict adaptation effect). These behavioral conflict adaptation effects were accompanied by changes in activity in visual color-selective areas (V4, V4α), while there was no modulation by previous trial compatibility in a visual word-selective area (VWFA). Our results provide further evidence for the notion, that adaptation to recent conflict seems to be based mainly on enhancement of processing of the task-relevant information. PMID:25784868

  17. Adaptation to recent conflict in the classical color-word Stroop-task mainly involves facilitation of processing of task-relevant information

    PubMed Central

    Purmann, Sascha; Pollmann, Stefan

    2015-01-01

    To process information selectively and to continuously fine-tune selectivity of information processing are important abilities for successful goal-directed behavior. One phenomenon thought to represent this fine-tuning are conflict adaptation effects in interference tasks, i.e., reduction of interference after an incompatible trial and when incompatible trials are frequent. The neurocognitive mechanisms of these effects are currently only partly understood and results from brainimaging studies so far are mixed. In our study we validate and extend recent findings by examining adaption to recent conflict in the classical Stroop task using functional magnetic resonance imaging. Consistent with previous research we found increased activity in a fronto-parietal network comprising the medial prefrontal cortex, ventro-lateral prefrontal cortex, and posterior parietal cortex when contrasting incompatible with compatible trials. These areas have been associated with attentional processes and might reflect increased cognitive conflict and resolution thereof during incompatible trials. While carefully controlling for non-attentional sequential effects we found smaller Stroop interference after an incompatible trial (conflict adaptation effect). These behavioral conflict adaptation effects were accompanied by changes in activity in visual color-selective areas (V4, V4α), while there was no modulation by previous trial compatibility in a visual word-selective area (VWFA). Our results provide further evidence for the notion, that adaptation to recent conflict seems to be based mainly on enhancement of processing of the task-relevant information. PMID:25784868

  18. Hydrocarbon occurrences in igneous and metamorphic rocks: Plays of the 1990s

    SciTech Connect

    Harrelson, D.W.

    1989-09-01

    A review of available geologic literature has indicated numerous references detailing the occurrences of hydrocarbon in igneous and metamorphic rocks. Notable among these references is a paper by Chung-Hsiang P'an and a group of papers edited by Sidney Powers. Collectively, these papers conclude a biogenic source for hydrocarbons, most of which occur in (1) weathered igneous and metamorphic reservoir rocks that are higher than the source rocks (e.g., Amarillo field) or (2) igneous and metamorphic rocks that exert structural or stratigraphic control on the reservoir or source rocks (e.g., Jackson dome and the Wiggins anticline-Hancock ridge). It should be noted that a new twist on the abiogenic origin of some inert hydrocarbon gases (i.e., helium and nitrogen) proposes a degassing of igneous and metamorphic rocks from sources in the underlying mantle. Recent european super-deep tests (e.g., the Siljan Ring and the Kola SG-3 testholes) have attempted, with mixed results, to verify this theory. Drilling for these deep igneous and metamorphic prospects today is considered at or below economic basement or worse - a rank wildcat. However, these plays should become increasingly commercial in the 1990s as deeper drilling technology progresses, the current oil glut is eliminated, and more exotic deep gas prospects become accepted.

  19. Middle Jurassic to early Cretaceous igneous rocks along eastern North American continental margin

    SciTech Connect

    Jansa, L.F.; Pe-Piper, G.

    1988-03-01

    Late Middle Jurassic and Early Cretaceous mafic dikes, sills, flows, and local volcaniclastic sediments are intercalated within continental shelf sediments from the Baltimore Canyon Trough northward to the Grand Banks of Newfoundland. The igneous rocks on the eastern North American margin are mainly alkali basalts of intraplate affinity. The late Middle Jurassic igneous activity was of short duration, at about 140 Ma, and was restricted to Georges Bank where it led to construction of several volcanic cones. The main period of igneous activity was concentrated at about 120 Ma in the Aptian/Berremian. The activity consists of dike swarms in Baltimore Canyon, occasional dikes on the Scotian Shelf, and the growth of stratovolcanoes on the Scotian Shelf and Grand Banks. Younger dikes (approx. 95 Ma) also are present on the Grand Banks. With regard to oil exploration on the continental margin, care must be taken to properly identify igneous and volcaniclastic rocks on mechanical logs, drill cuttings, and cores. Reflection seismic profiles can be used to map the areal extent of sills, flows, and low-angle dikes, which commonly show distinctive seismic responses. However, steeply dipping dikes generally produce little, if any, seismic response. Isotopic-age determinations of igneous rocks, combined with biostratigraphic-age determinations of adjacent strata, are invaluable for stratigraphic correlation, establishing chronology of seismic sequences, and analysis of basin sedimentation and tectonic history. 9 figures, 2 tables.

  20. The ammonium content in the Malayer igneous and metamorphic rocks (Sanandaj-Sirjan Zone, Western Iran)

    NASA Astrophysics Data System (ADS)

    Ahadnejad, Vahid; Hirt, Ann Marie; Valizadeh, Mohammad-Vali; Bokani, Saeed Jabbari

    2011-04-01

    The ammonium (NH4+) contents of the Malayer area (Western Iran) have been determined by using the colorimetric method on 26 samples from igneous and metamorphic rocks. This is the first analysis of the ammonium contents of Iranian metamorphic and igneous rocks. The average ammonium content of metamorphic rocks decreases from low-grade to high-grade metamorphic rocks (in ppm): slate 580, phyllite 515, andalusite schist 242. In the case of igneous rocks, it decreases from felsic to mafic igneous types (in ppm): granites 39, monzonite 20, diorite 17, gabbro 10. Altered granitic rocks show enrichment in NH4+ (mean 61 ppm). The high concentration of ammonium in Malayer granites may indicate metasedimentary rocks as protoliths rather than meta-igneous rocks. These granitic rocks (S-types) have high K-bearing rock-forming minerals such as biotite, muscovite and K-feldspar which their potassium could substitute with ammonium. In addition, the high ammonium content of metasediments is probably due to inheritance of nitrogen from organic matter in the original sediments. The hydrothermally altered samples of granitic rocks show highly enrichment of ammonium suggesting external sources which intruded additional content by either interaction with metasedimentary country rocks or meteoritic solutions.

  1. Can we observe changes in mRNA “state”? Overview of methods to study mRNA interactions with regulatory proteins relevant in cancer related processes

    PubMed Central

    Zurla, C.; Jung, J.; Santangelo, P. J.

    2015-01-01

    RNA binding proteins (RBP) regulate the editing, localization, stabilization, translation, and degradation of ribonucleic acids (RNA) through their interactions with specific cis-acting elements within target RNAs. Post-transcriptional regulatory mechanisms are directly involved in the control of the immune response and stress response and their alterations play a crucial role in cancer related processes. In this review, we discuss mRNAs and RNA binding proteins relevant to tumorigenesis, current methodologies for detecting RNA interactions, and last, we describe a novel method to detect such interactions, which combines peptide modified, RNA imaging probes (FMTRIPs) with proximity ligation (PLA) and rolling circle amplification (RCA). This assay detects native RNA in a sequence specific and single RNA sensitive manner, and PLA allows for the quantification and localization of protein–mRNA interactions with single-interaction sensitivity in situ. PMID:26605378

  2. Structure of different within-plate magmatic system of large igneous provinces

    NASA Astrophysics Data System (ADS)

    Sharkov, E.

    2009-04-01

    It is generally accepted that formation of continental large igneous provinces (LIPs) is linked with ascending of mantle superplumes. However, it is not clear yet why and how magmatic systems appeared and functionated. It is known that LIPs are formed by numerous magmatic centers, which imply existence of individual magmatic systems beneath them. Such a situation can be explained by presence of protuberances (local plumes) on the surface of extended superplume heads, where processes of adiabatic melting occurred give rise to formation of magmatic systems. Newly-formed melts on their way to the surface pass through complicate system of conduits and transitional magma chambers, where they were undergone by different processes of crystallizing differentiation, mixing, assimilation of wall-rocks, etc. According to data available, three major levels of transitional magmatic chambers, linked by systems of feeder conduits (dikes), occurred within the crust. Each of them is responsible for transformation of a primary melt in different extent: The lowest level with the largest chambers, located along boundary between upper margin of the plume head and incumbent rigid lithosphere; they are responsible for the underplating phenomenon. Processes of contamination mantle-derived magmas by crustal material can play essential role here, especially in the late Archean and early Paleoproterozoic when they led to appearance of specific mantle-crustal magmas of siliceous high-Mg series (SHMS), which formed large igneous provinces with numerous mafic-iltramafic layered intrusions (Sharkov, Bogina, 2006). It suggests that formation of this series was linked with "floating up" of chambers (batches) of high-temperature ultramafic magmas through the upper part of lithospheric mantle and mafic lower crust by zone refinement mechanism, i.e. by melting material of the chamber's roof and crystallization at their bottoms. As a result, the primary melt gradually enriched in crustal material

  3. Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt.

    PubMed

    Abbady, Adel G E; El-Arabi, A M; Abbady, A

    2006-01-01

    Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 microWm(-3) (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 microWm(-3) (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites. PMID:16120480

  4. Igneous history of the aubrite parent asteroid - Evidence from the Norton County enstatite achondrite

    NASA Technical Reports Server (NTRS)

    Okada, Akihiko; Keil, Klaus; Taylor, G. Jeffrey; Newsom, Horton

    1988-01-01

    Numerous specimens of the Norton County enstatite achondrite (aubrite) were studied by optical microscopy, electron microprobe, and neutron-activation analysis. Norton County is found to be a fragmental impact breccia, consisting of a clastic matrix made mostly of crushed enstatite, into which are embedded a variety of mineral and lithic clasts of both igneous and impact melt origin. The Norton County precursor materials were igneous rocks, mostly plutonic orthopyroxenites, not grains formed by condensation from the solar nebula. The Mg-silicate-rich aubrite parent body experienced extensive melting and igneous differentiation, causing formation of diverse lithologies including dunites, plutonic orthopyroxenites, plutonic pyroxenites, and plagioclase-silica rocks. The presence of impact melt breccias (the microporphyritic clasts and the diopside-plagioclase-silica clast) of still different compositions further attests to the lithologic diversity of the aubrite parent body.

  5. Timing and chemistry of igneous events associated with the Southern Oklahoma Aulacogen

    NASA Astrophysics Data System (ADS)

    Charles Gilbert, M.

    1983-05-01

    Igneous activity in the Southern Oklahoma Aulacogen of North America was concentrated in the early rifting stages of aulacogen development. The time span over which liquids rose may not have exceeded 50 m.y. and certainly terminated before the Upper Cambrian. Igneous activity began with three basaltic liquids, stratigraphically identifiable but perhaps not all distinct genetically. This was followed by one large rhyolitic-granitic episode of A-type character. One final basaltic event ended the activity. All the basaltic types seem to be tholeiitic showing more kinship with either the older, Proterozoic North American Midcontinental Rift or the northern part of the Cenozoic Rio Grande Rift, than the Cenozoic East African Rift. Two major uplifts occurred: one between the earlier basalts and the rhyolite, and one much later, after all igneous activity was over, in the Pennsylvanian.

  6. Using the Iterative Input variable Selection (IIS) algorithm to assess the relevance of ENSO teleconnections patterns on hydro-meteorological processes at the catchment scale

    NASA Astrophysics Data System (ADS)

    Beltrame, Ludovica; Carbonin, Daniele; Galelli, Stefano; Castelletti, Andrea

    2014-05-01

    Population growth, water scarcity and climate change are three major factors making the understanding of variations in water availability increasingly important. Therefore, reliable medium-to-long range forecasts of streamflows are essential to the development of water management policies. To this purpose, recent modelling efforts have been dedicated to seasonal and inter-annual streamflow forecasts based on the teleconnection between "at-site" hydro-meteorological processes and low frequency climate fluctuations, such as El Niño Southern Oscillation (ENSO). This work proposes a novel procedure for first detecting the impact of ENSO on hydro-meteorological processes at the catchment scale, and then assessing the potential of ENSO indicators for building medium-to-long range statistical streamflow prediction models. Core of this procedure is the adoption of the Iterative Input variable Selection (IIS) algorithm that is employed to find the most relevant forcings of streamflow variability and derive predictive models based on the selected inputs. The procedure is tested on the Columbia (USA) and Williams (Australia) Rivers, where ENSO influence has been well-documented, and then adopted on the unexplored Red River basin (Vietnam). Results show that IIS outcomes on the Columbia and Williams Rivers are consistent with the results of previous studies, and that ENSO indicators can be effectively used to enhance the streamflow forecast models capabilities. The experiments on the Red River basin show that the ENSO influence is less pronounced, inducing little effects on the basin hydro-meteorological processes.

  7. Mantle Redox Conditions in the North Atlantic Igneous Province

    NASA Astrophysics Data System (ADS)

    Heister, L. E.; Gras, M. A.; Lesher, C. E.

    2004-12-01

    The North Atlantic igneous province (NAIP) has long been viewed as a region of anomalous mantle upwelling related to plume activity, continental rifting, and a heterogeneous mantle source. Prior to continental rifting in the Tertiary, the northern portion of the region was the site of closure of the Iapetus ocean basin. This tectonic event may have contributed to heterogeneities within the upper mantle and altered its oxidation state relative to the ambient mantle. Vanadium has been shown to be a useful indicator of redox conditions due to its multiple valence states (e.g. [1-2]). In mantle minerals, vanadium becomes increasingly incompatible under more oxidizing conditions [3]. Because both scandium and vanadium are moderately incompatible during melting, the Sc/V ratio of primitive basalts can be used to investigate the oxidation state of the mantle [1-3]. We have examined the Sc/V ratios of primitive lavas from the mid-Atlantic ridge (MAR), Iceland, and the East Greenland margin to determine if there are spatial or temporal variations in the oxidation state of the NAIP mantle. The Sc/V ratios for MAR basalts are 0.13-0.20 (GEOROC chemical database); while Icelandic basalts range from 0.10-0.25 with an average of 0.16 (1 σ =0.05). The entire range of Sc/V ratios of the Paleogene East Greenland basalts is 0.07-0.17 with an average of 0.10 (1 σ = 0.05). The Sc/V ratios of Icelandic basalts are similar to MAR basalts, but the East Greenland lavas are distinctly lower than both the MAR and Iceland. The Sc/V ratio also can vary as a function of mean pressure of melting (i.e. spinel versus garnet lherzolite). To test the relative importance of melting systematics, source composition, and oxygen fugacity on the Sc/V systematics for NAIP basalts, we incorporated the oxygen-fugacity-dependent V mineral-melt partitioning data of [3] into the polybaric decompression melting model REEBOX [4]. The best-fit model parameters for the majority of the Iceland and MAR basalts

  8. Supercontinents, Plate Tectonics, Large Igneous Provinces and Deep Mantle Heterogeneities

    NASA Astrophysics Data System (ADS)

    Torsvik, T. H.; Steinberger, B.; Burke, K.; Smethurst, M. A.

    2008-12-01

    The formation and break-up of supercontinents is a spectacular demonstration of the Earth's dynamic nature. Pangea, the best-documented supercontinent, formed at the end of the Palaeozoic era (320 Ma) and its dispersal, starting in the Early Jurassic (190 Ma), was preceded by and associated with widespread volcanic activity, much of which produced Large Igneous Provinces (LIPs), but whether any of the heat or material involved in the generation of LIP rocks comes from greater depths has remained controversial. Two antipodal Large Low Shear wave Velocity Provinces with centre of mass somewhat south of the equator (African and Pacific LLSVPs), isolated within the faster parts of the deep mantle dominate all global shear- wave tomography models. We have tested eight global models and two D" models: They all show that deep- plume sourced hotspots and most reconstructed LIPs for the last 300 million years project radially downwards to the core-mantle-boundary near the edges of the LLSVPs showing that the plumes that made those hotspots and LIPS came only from those plume generation zones. This is a robust result because it is observed in multiple reference frames, i.e. fixed/moving hotspot and palaeomagnetic frames, and in the latter case whether the effect of True Polar Wander (TPW) is considered or not. Our observations show that the LLSVPs must have remained essentially stable in their present position for the last 300 million years. LIPs have erupted since the Archean and may all have been derived from the margins of LLSVPs but whether the African and Pacific LLSVPs have remained the same throughout Earth's history is less certain although analogous structures on Mars do indicate long-term stability on that planet. Deep mantle heterogeneities and the geoid have remained very stable for the last 300 million years, and the possibility is therefore open for speculating on links to Pangea assembly. In a numerical model, Zhong et al. (2007, EPSL) argued that Pangea

  9. Monitoring of the manufacturing process for ambroxol hydrochloride tablet using NIR-chemometric methods: compression effect on content uniformity model and relevant process parameters testing.

    PubMed

    Yang, Hongqin; Liao, Xiaoxiang; Peng, Feng; Wang, Wan; Liu, Yanxin; Yan, Jin; Li, Hui

    2015-01-01

    This study aimed at using near-infrared (NIR) spectroscopy to monitor compaction pressure for simultaneously determining the tensile strength and content uniformity, as well as moisture and mean particle size of ambroxol hydrochloride tablets. The content uniformity, compression force and tensile strength of the laboratory samples were obtained by pressing a mixture of active principle and excipient components into tablets. To reduce the spectral baseline shift of the laboratory samples, the compaction pressure applied to the mixture was assessed by a variable pressure test. Production samples were added to the test and subjected to principal component analysis. The expanded partial least-squares (PLS) calibration model used to quantify the active content was more accurate than the model constructed from laboratory samples using the production tablets included in the calibration set. The model showed good predictability, with correlation coefficient (R) 0.9977. The validation and reliability of the content model were evaluated to determine trueness and reliability for the measurement of individual production tablets and the laboratory tablets with drug content ranging from 24 to 36 mg. The PLS calibration models for compression force and tensile strength were constructed using the same spectral set assuming both were highly related. These models yielded high R values (0.9955 and 0.9910). The R values of the moisture and mean particle size were 0.9994 and 0.9919, respectively. This study demonstrated that NIR spectroscopy combined with chemometric techniques can be successfully used to quantitatively monitor the tablet manufacturing process in the pharmaceutical industry. PMID:25738811

  10. Elevation and igneous crater modification on Venus: Implications for magmatic volatile content

    NASA Technical Reports Server (NTRS)

    Wichman, R. W.

    1993-01-01

    Although most impact craters on Venus preserve nearly pristine crater rim and ejecta features, a small number of craters have been identified showing clear evidence of either igneous intrusion emplacement (floor-fracturing) beneath the crater floor or of volcanically embayed exterior ejecta deposits. Since the volcanically embayed craters consistently occur at higher elevations than the identified floor-fractured craters, this report proposes that igneous crater modification on Venus is elevation dependent. This report describes how regional variations in magmatic neutral buoyancy could produce such elevation dependent crater modification and considers the implications for typical magmatic volatile contents on Venus.

  11. Distribution of Igneous Rocks in Medina and Uvalde Counties, Texas, as Inferred from Aeromagnetic Data

    USGS Publications Warehouse

    Smith, David V.; McDougal, Robert R.; Smith, Bruce D.; Blome, Charles D.

    2008-01-01

    A high-resolution aeromagnetic survey was flown in 2001 over Medina and Uvalde Counties, Texas, as part of a multi-disciplinary investigation of the geohydrologic framework of the Edwards aquifer in south-central Texas. The objective of the survey was to assist in mapping structural features that influence aquifer recharge and ground-water flow. The survey revealed hundreds of magnetic anomalies associated with igneous rocks that had previously been unmapped. This report presents an interpretation of the outcrops and subcrops of igneous rocks, based upon procedures of matched-filtering and potential field modeling.

  12. Aqueous alteration in CR chondrites: Meteorite parent body processes as analogue for long-term corrosion processes relevant for nuclear waste disposal

    NASA Astrophysics Data System (ADS)

    Morlok, Andreas; Libourel, Guy

    2013-02-01

    Aqueous alteration of carbonaceous chondrites is one of the fundamental processes on accreting planetesimals that changes pristine materials from the formation of the Solar System. The study of mineralogical, petrological and chemical changes resulting from this alteration provides insight into the physical and chemical setting of forming planetesimals. CR chondrites provide samples for all stages of aqueous alteration, from type 3 to 1 (entirely hydrated), and are thus suited to study the alteration of pristine materials in a coherent sequence. Vitrification is a common way to store and stabilize fission products and minor actinides resulting from the reprocessing of nuclear spent fuel in a nuclear boro-silica glass in steel containers. The waste material has to be stored safely for a period of at least 105-106 years in a clay-rich geological repository. Laboratory experiments being too short to follow the long-term evolution of these materials, we analyzed the mineralogical, petrological and chemical changes in a series of CR chondrites (Renazzo CR2, Al Rais CR2, and GRO 95577 CR1) to serve as analogues. Rims of secondary materials around metal grains in contact to the fine-grained matrix serve as analogue to the interface between steel containment and the surrounding clay-rich geological layer, while chondrule glassy mesostasis is used as a proxy of the nuclear glass. With increasing degree of aqueous alteration in the sequence, Renazzo → Al Rais → GRO 95577, the size of the rims increase. Fe-rich alteration rims are ˜10 μm in thickness around metal grains in the fine-grained matrix in Renazzo. In Al Rais, multi-layered structures of interchanging Fe, S and P/Ca-rich layers appear, with a thickness of up to ˜30 μm. In the highly altered GRO 95577, extensive inner and external rims of secondary phases reach up to ˜200 μm into the surrounding matrix. In chondrules, metal in contact with the altered mesostasis shows similar trends, but with thinner

  13. Stability of Mg-sulfates at-10C and the rates of dehydration/rehydration processes under conditions relevant to Mars

    USGS Publications Warehouse

    Wang, A.; Freeman, J.J.; Chou, I.-Ming; Jolliff, B.L.

    2011-01-01

    We report the results of low temperature (-10??C) experiments on the stability fields and phase transition pathways of five hydrous Mg-sulfates. A low temperature form of MgSO 47H 2O (LT-7w) was found to have a wide stability field that extends to low relative humidity (???13% RH at-10??C). Using information on the timing of phase transitions, we extracted information on the reaction rates of five important dehydration and rehydration processes. We found that the temperature dependencies of rate constants for dehydration processes differ from those of rehydration, which reflect differences in reaction mechanisms. By extrapolating these rate constants versus T correlations into the T range relevant to Mars, we can evaluate the possibility of occurrence of specific processes and the presence of common Mg-sulfate species present on Mars in different periods and locations. We anticipate in a moderate obliquity period, starkeyite and LH-MgSO 4H 2O should be two common Mg-sulfates at the surface, another polymorph MH-MgSO 4H 2O can exist at the locations where hydrothermal processes may have occurred. In polar regions or within the subsurface of other regions, meridianiite (coexisting with water ice, near 100% RH) and LT-7w (over a large RH range) are the stable phases. During a high obliquity period, meridianiite and LT-7w should exhibit widespread occurrence. The correlations of reaction rates versus temperature found in this study imply that dehydration and rehydration of hydrous Mg-sulfates would always be slower than the sublimation and crystallization of water ice, which would be supported by mission observations from Odyssey and by Mars Exploration Rovers. Copyright 2011 by the American Geophysical Union.

  14. An introduction to the application of X-ray microtomography to the three-dimensional study of igneous rocks

    SciTech Connect

    Baker, D.R.; Mancini, L.; Polacci, M.; Higgins, M.D.; Gualda, G.A.R.; Hill, R.J.; Rivers, M.L.

    2012-10-25

    Imaging rocks in three-dimensions through X-ray microtomography enables routine visualization of structures in samples, which can be spatially resolved down to the sub-micron scale. Although X-ray tomography has been applied in biomedical research and clinical settings for decades, it has only recently been applied to studies of rocks, and few geoscientists realize its value and potential. This contribution provides an introduction to the principles and techniques of X-ray microtomography to the study of igneous rock textures as well as reviewing the current state of the art. We hope that this short review will encourage more geoscientists to apply X-ray microtomography in their research and that this will lead to new insights into the processes that occur in magmatic (as well as other geological) systems.

  15. Origin and evolution of a submarine large igneous province: the Kerguelen Plateau and Broken Ridge, southern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Frey, F. A.; Coffin, M. F.; Wallace, P. J.; Weis, D.; Zhao, X.; Wise, S. W.; Wähnert, V.; Teagle, D. A. H.; Saccocia, P. J.; Reusch, D. N.; Pringle, M. S.; Nicolaysen, K. E.; Neal, C. R.; Müller, R. D.; Moore, C. L.; Mahoney, J. J.; Keszthelyi, L.; Inokuchi, H.; Duncan, R. A.; Delius, H.; Damuth, J. E.; Damasceno, D.; Coxall, H. K.; Borre, M. K.; Boehm, F.; Barling, J.; Arndt, N. T.; Antretter, M.

    2000-02-01

    Oceanic plateaus form by mantle processes distinct from those forming oceanic crust at divergent plate boundaries. Eleven drillsites into igneous basement of Kerguelen Plateau and Broken Ridge, including seven from the recent Ocean Drilling Program Leg 183 (1998-99) and four from Legs 119 and 120 (1987-88), show that the dominant rocks are basalts with geochemical characteristics distinct from those of mid-ocean ridge basalts. Moreover, the physical characteristics of the lava flows and the presence of wood fragments, charcoal, pollen, spores and seeds in the shallow water sediments overlying the igneous basement show that the growth rate of the plateau was sufficient to form subaerial landmasses. Most of the southern Kerguelen Plateau formed at ˜110 Ma, but the uppermost submarine lavas in the northern Kerguelen Plateau erupted during Cenozoic time. These results are consistent with derivation of the plateau by partial melting of the Kerguelen plume. Leg 183 provided two new major observations about the final growth stages of the Kerguelen Plateau. 1: At several locations, volcanism ended with explosive eruptions of volatile-rich, felsic magmas; although the total volume of felsic volcanic rocks is poorly constrained, the explosive nature of the eruptions may have resulted in globally significant effects on climate and atmospheric chemistry during the late-stage, subaerial growth of the Kerguelen Plateau. 2: At one drillsite, clasts of garnet-biotite gneiss, a continental rock, occur in a fluvial conglomerate intercalated within basaltic flows. Previously, geochemical and geophysical evidence has been used to infer continental lithospheric components within this large igneous province. A continental geochemical signature in an oceanic setting may represent deeply recycled crust incorporated into the Kerguelen plume or continental fragments dispersed during initial formation of the Indian Ocean during breakup of Gondwana. The clasts of garnet-biotite gneiss are

  16. miRNA profiling of high, low and non-producing CHO cells during biphasic fed-batch cultivation reveals process relevant targets for host cell engineering.

    PubMed

    Stiefel, Fabian; Fischer, Simon; Sczyrba, Alexander; Otte, Kerstin; Hesse, Friedemann

    2016-05-10

    Fed-batch cultivation of recombinant Chinese hamster ovary (CHO) cell lines is one of the most widely used production modes for commercial manufacturing of recombinant protein therapeutics. Furthermore, fed-batch cultivations are often conducted as biphasic processes where the culture temperature is decreased to maximize volumetric product yields. However, it remains to be elucidated which intracellular regulatory elements actually control the observed pro-productive phenotypes. Recently, several studies have revealed microRNAs (miRNAs) to be important molecular switches of cell phenotypes. In this study, we analyzed miRNA profiles of two different recombinant CHO cell lines (high and low producer), and compared them to a non-producing CHO DG44 host cell line during fed-batch cultivation at 37°C versus a temperature shift to 30°C. Taking advantage of next-generation sequencing combined with cluster, correlation and differential expression analyses, we could identify 89 different miRNAs, which were differentially expressed in the different cell lines and cultivation phases. Functional validation experiments using 19 validated target miRNAs confirmed that these miRNAs indeed induced changes in process relevant phenotypes. Furthermore, computational miRNA target prediction combined with functional clustering identified putative target genes and cellular pathways, which might be regulated by these miRNAs. This study systematically identified novel target miRNAs during different phases and conditions of a biphasic fed-batch production process and functionally evaluated their potential for host cell engineering. PMID:27002234

  17. Siderophile and volatile trace elements in 72255 and 72275. [meteoritic and igneous composition of lunar rocks

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Ganapathy, R.; Higuchi, H.; Anders, E.

    1974-01-01

    Of six samples from boulder 1 at Station 2, four contain a unique meteoritic component, which is attributed to the Crisium projectile. The other two samples are meteorite free, igneous rocks: an unusual, alkali- and Ge-rich pigeonitic basalt, and an alkali-poor norite of unexceptional trace element chemistry.

  18. FeO and MgO in plagioclase of lunar anorthosites: Igneous or metamorphic?

    NASA Technical Reports Server (NTRS)

    Phinney, W. C.

    1994-01-01

    The combined evidence from terrestrial anorthosites and experimental laboratory studies strongly implies that lunar anorthosites have been subjected to high-grade metamorphic events that have erased the igneous signatures of FeO and MgO in their plagioclases. Arguments to the contrary have, to this point, been more hopeful than rigorous.

  19. Biological energy from the igneous rock enhances cell growth and enzyme activity.

    PubMed

    Lin, Y; Kuo, H; Chen, C; Kuo, S

    2000-08-01

    Some effects from natural resources might be ignored and unused by humans. Environmental hormesis could be a phenomena necessary to bio-organism existence on earth. Since 1919, radiation and some heavy metal hormesis from the environment were proved in various reports. In this study, igneous rock with very low radioactivity and high ferrous activity was measured by multichannel analyzer and inductively coupled plasma analyzer. The water treated by igneous rock, both directly soaked or indirectly in contact, induced increased activities of glucose oxidase, catalase, peroxidase, and superoxide dismutase. It also increased cell growth of SC-M1, HCT-15, Raji, and fibroblast cell lines. The water after treatment of igneous rock had no change in pH values, but displayed decreased conductivity values. We assume that the igneous rock could transfer energy to water to change the molecular structure or conformation of water cluster, or by radiation hormesis effect could then induce increased enzyme activity and cell growth. It is also possible that the energy from rock may combine radiation hormesis with other transferable biological energy forms to change water cluster conformation. PMID:11056378

  20. Petrology, geochemistry and geochronology of the Chilka Lake igneous complex, Orissa state, India

    NASA Astrophysics Data System (ADS)

    Sarkar, Amitabha; Bhanumathi, L.; Balasubrahmanyan, M. N.

    1981-04-01

    The Chilka Lake igneous complex of Orissa, the largest known anortosite massif of the Indian Shield, occurs in a catazonal environment of high-grade metamorphics of the Eastern Ghats Precambrian Orogenic Province. The syntectonic massif consists of the anorthositic Balugaon dome, leuconoritic Rambha lobe and quartz-mangeritic Kallikota cover. A completely gradational suite comprising anorthosite-leuconorite-norite-minor jotunite (the anorthositic suite) constitutes most of the complex. The subordinate of suite of acid rocks spatially associated with this is of a broad quartz-mangeritic lithology with minor granitic rocks (the acidic suite). Geochemical evolution of the complex in the sequence anorthosite-leuconorite-norite-jotunite-acidic rocks shows moderate iron enrichment in the noritic-jotunitic stage and is marked by an overall decrease in Al 2O 3, CaO, MgO, Ni/Co, Sr/Ba, K/Rb and increase in SiO 2, K 2O, V/Ni, K/Ba and Rb/Sr. Such progressive variation in geochemical parameters appears (i) essentially gradual and frequently overlapping in rock members of the intergradational anorthositic suite and (ii) rather abrupt across transition zones between the anorthositic suite and the acidic suite due to near absence of intervening intermediate lithologies. RbSr whole rock isochron studies indicate that the complex was emplaced ca. 1400 Ma ago. The initial 87Sr/ 68Sr (0.70661) implies limited hybridisation of the parent magma prior to emplacement. A critical appraisal of all the available evidence suggests that (i) the anorthositic suite of rocks form a perfectly consanguinous and comagmatic assemblage and (ii) the spatially associated acidic suite emerged through a convergence of magmatic and metasomatic processes (the latter brought about by contact anatexis of the host rocks). The complex as well as the host metamorphics are intruded by an atectonic suite of noritic dykes emplaced ca 850 Ma ago.

  1. Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts

    NASA Astrophysics Data System (ADS)

    Richards, M. A.; Ridley, V. A.

    2010-12-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as “underplating,” are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better

  2. Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts

    NASA Astrophysics Data System (ADS)

    Richards, Mark; Ridley, Victoria

    2010-05-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marqueses, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better

  3. Deep crustal structure beneath large igneous provinces and the petrologic evolution of flood basalts

    NASA Astrophysics Data System (ADS)

    Ridley, Victoria A.; Richards, Mark A.

    2010-09-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ˜ 6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ˜5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp ˜ 7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hot spots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ˜6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ˜15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby

  4. PROBABILISTIC ANALYSES OF WASTE PACKAGE QUANTITIES IMPACTED BY POTENTIAL IGNEOUS DISRUPTION AT YUCCA MOUNTAIN

    SciTech Connect

    M.G. Wallace

    2005-08-26

    A probabilistic analysis was conducted to estimate ranges for the numbers of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analyses include disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application for the Yucca Mountain Project (YMP). The first scenario, igneous intrusion, investigated the case where one or more igneous dikes intersect the repository. A swarm of dikes was characterized by distributions of length, width, azimuth, and number of dikes and the spacings between them. Through the use in part of a latin hypercube simulator and a modified video game engine, mathematical relationships were built between those parameters and the number of waste packages hit. Corresponding cumulative distribution function curves (CDFs) for the number of waste packages hit under several different scenarios were calculated. Variations in dike thickness ranges, as well as in repository magma bulkhead positions were examined through sensitivity studies. It was assumed that all waste packages in an emplacement drift would be impacted if that drift were intersected by a dike. Over 10,000 individual simulations were performed. Based on these calculations, out of a total of over 11,000 planned waste packages distributed over an area of approximately 5.5 km{sup 2} , the median number of waste packages impacted was roughly 1/10 of the total. Individual cases ranged from 0 waste packages to the entire inventory being impacted. The igneous intrusion analysis involved an explicit characterization of dike-drift intersections, built upon various distributions that reflect the uncertainties associated with the inputs. The second igneous scenario, volcanic eruption (eruptive conduits), considered the effects of conduits formed

  5. Probablistic Analyses of Waste Package Quantities Impacted by Potential Igneous Disruption at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Wallace, M. G.; Iuzzolina, H.

    2005-12-01

    A probabilistic analysis was conducted to estimate ranges for the numbers of waste packages that could be damaged in a potential future igneous event through a repository at Yucca Mountain. The analysis includes disruption from an intrusive igneous event and from an extrusive volcanic event. This analysis supports the evaluation of the potential consequences of future igneous activity as part of the total system performance assessment for the license application for the Yucca Mountain Project (YMP). The first scenario, igneous intrusion, investigated the case where one or more igneous dikes intersect the repository. A swarm of dikes was characterized by distributions of length, width, azimuth, and number of dikes and the spacings between them. Through the use in part of a latin hypercube simulator and a modified video game engine, mathematical relationships were built between those parameters and the number of waste packages hit. Corresponding cumulative distribution function curves (CDFs) for the number of waste packages hit under several different scenarios were calculated. Variations in dike thickness ranges, as well as in repository magma bulkhead positions were examined through sensitivity studies. It was assumed that all waste packages in an emplacement drift would be impacted if that drift was intersected by a dike. Over 10,000 individual simulations were performed. Based on these calculations, out of a total of over 11,000 planned waste packages distributed over an area of approximately 5.5 km2 , the median number of waste packages impacted was roughly 1/10 of the total. Individual cases ranged from 0 waste packages to the entire inventory being impacted. The igneous intrusion analysis involved an explicit characterization of dike-drift intersections, built upon various distributions that reflect the uncertainties associated with the inputs. The second igneous scenario, volcanic eruption (eruptive conduits), considered the effects of conduits formed in

  6. Geochemistry of Sarvabad basic igneous rocks from northern Sanandaj - Sirjan Magmatic Arc, Iran

    NASA Astrophysics Data System (ADS)

    Mahmoudi, H.; Ghorbani, M.; Azizi, H.

    2009-12-01

    Sanandaj - Sirjan Magmatic Arc (SSMA) as a segment of Alpine -Himalayan magmatic belt embrace a wide spectrum of igneous rocks, both volcanic and plutonic, from basic to felsic compositions. The igneous rocks which are mainly calc-alkaline are attributed to the subduction of Neotethyan oceanic slab beneath central Iranian plate in Mesozoic time (Berberian and Berberian, 1981; Omrani et al., 2008). In the present study the focus is made on the geochemistry and petrography of igneous rocks from northwestern end of the SSMA, in Sarvabad area, in order to elucidate their geodynamic setting. A set of 30 rock samples were analyzed for major and selected trace elements. Mafic igneous bodies from northern SSMA are regarded as post - collisional plutonic bodies of Eocene - Oligocene age (Ghasemi and Talbot, 2006). Azizi and Moinevaziri (2009) considered the igneous rocks from the northern SSMA, at Sonqor - Baneh area, as the products of subduction that continued to the Paleogene time. Investigations carried out in the course of present study demonstrate that the Sarvabad basic igneous rocks, shown on the magmatic map of Iran (Emami et al., 1993) as gabbroic plutons, are composed of volcanic, subvolcanic and plutonic rocks of basic composition. The silica and Mg number of the rocks vary in the ranges 49-52 wt. % and 54-68, respectively. The volcanic rocks are vitrophyric to porphyritic with some plagioclase, olivine and clinopyroxene microphenocrysts. In the subvolcanic and plutonic bodies, plagioclase, clinopyroxene and some amphibole and Fe-Ti oxides are the major constituents. These igneous rocks indicate tholeitic affinity and cover the typical mantle array on a Zr/Nb vs. Y/Nb plot. Occurrences of a few ultramafic bodies found as metric - size isolated lenses in the basic igneous rocks highlight the spatial characteristic of these rocks; the existence of an ophiolitic rock assemblage nearby. Located toward the southwest of Sarvabad basic igneous rocks, is a Cretaceous

  7. Distinguishing peperite from other sediment-matrix igneous breccias: Lessons from the Iberian Pyrite Belt

    NASA Astrophysics Data System (ADS)

    Rosa, Carlos J. P.; McPhie, Jocelyn; Relvas, Jorge M. R. S.

    2016-04-01

    Breccias composed of coarse monomictic porphyritic igneous clasts and fine-grained matrix are common in subaqueous volcanic successions. We use the descriptive name "sediment-matrix igneous breccia" for this facies and have recognized at least five different origins among examples in the Iberian Pyrite Belt: (1) peperite; (2) sediment-infill volcanic breccia; (3) mud-matrix resedimented hyaloclastite; (4) mud-rich water-settled fiamme breccia; and (5) apparent sediment-matrix igneous breccia. Because the components and textures are similar, discriminating among the different origins can be very difficult. Both peperite and sediment-infill volcanic breccia can occur along top contacts of thick intervals of felsic coherent and monomictic breccia facies. The presence of peperite indicates that the contact is intrusive, whereas the presence of sediment-infill volcanic breccia indicates that the contact is depositional. Hence, correct distinction between peperite and sediment-infill volcanic breccia is an important means of discriminating felsic intrusions from felsic lavas and domes. The distinction underpins the reconstruction of volcanic centers and facies architecture, and the ordering of volcanic, intrusive, sedimentary and mineralizing events in ancient submarine volcanic successions. In addition, in volcanic-hosted massive sulfide districts such as the Iberian Pyrite Belt, paleoseafloor positions are considered highly prospective for massive sulfide ore bodies. Correct interpretation of sediment-matrix igneous breccias is also important in this context, because sediment-infill volcanic breccia, mud-matrix resedimented hyaloclastite and mud-rich water-settled fiamme breccia all form or are deposited at the seafloor, and hence delineate paleoseafloor positions. In contrast, peperite and apparent sediment-matrix igneous breccias form subsurface and do not delineate paleoseafloor positions.

  8. In situ observation of crystal growth in a basalt melt and the development of crystal size distribution in igneous rocks

    NASA Astrophysics Data System (ADS)

    Ni, Huaiwei; Keppler, Hans; Walte, Nicolas; Schiavi, Federica; Chen, Yang; Masotta, Matteo; Li, Zhenjiang

    2014-05-01

    To understand the solidification processes of natural magma and the texture evolution of igneous rocks, we have carried out in situ observation of the crystallization of a high-K basaltic melt cooling from ~1,240 °C in a moissanite cell. In a series of experiments with different thermal history, olivine or clinopyroxene (cpx) appeared as the liquidus phase before the formation of plagioclase. During cooling at 100 °C/h, the morphology of olivine and cpx transited from tabular to hopper habit. To first order approximation, crystal grow rate (2 × 10-9 to 7 × 10-9 m/s for olivine and 6 × 10-9 to 17 × 10-9 m/s for cpx), probably limited by chemical diffusion, is proportional to crystal size. In one experiment dominated by olivine crystallization, the good image quality allows the analysis of texture evolution over an extended period. Nucleation of olivine occurred only in a narrow temperature and time interval below the liquidus. Two-dimensional length- and area-based crystal size distributions (CSDs) show counterclockwise rotation around axes of 8 μm and 100 μm2, which is consistent with the proportionate crystal growth. Both CSDs and direct observation show the dissolution of small crystals and Ostwald ripening. These data suggest that conventional analyses of crystal size distributions of igneous rocks may be in error—the slope of the CSD cannot be interpreted in terms of a uniform growth rate, and the intercept with the vertical axis does not correspond to a nucleation density.

  9. Magma Emplacement and the 3D Geometry of Igneous Bodies in Rift Basins: Insights from the Bornu Basin, Onshore NE Nigeria

    NASA Astrophysics Data System (ADS)

    Suleiman, Adamu; Jackson, Christopher; Magee, Craig; Fraser, Alastair

    2016-04-01

    Recent studies of regional unconformities in the circum-South Atlantic tectonic plates have linked unconformity age to the timing of changes in the azimuth of oceanic fracture zones, caused by plate interactions during opening of the South Atlantic. This observation is significant, proposing that a plate boundary geodynamic processes are transmitted into and expressed in plate interiors. However, it is not yet clear if and how other geologic events, such as intra-plate magmatism, may be linked to changes in the oceanic fracture azimuthal geometry. Here we use 2D and 3D seismic reflection, geochemical, borehole datasets and outcrop observations from the Bornu Basin, one of several intra-continental rift basins located in NE Nigeria to constrain the 3D geometry of igneous bodies and magmatic emplacement processes. This allows us to link South Atlantic plate boundary geodynamics and magmatism in the surrounding continental rift basins. Seismic attributes, reflection intensity, relative acoustic impedance, were used to identify and map igneous intrusions. Saucer-shaped sills are the most common type of intrusion, although en-echelon sills, up to 1.4 km in length, were also identified. The 3D geometry of the sills reveals the detailed structural components like inner sill, inclined sheets and outer sill. A mapped bifurcating network of the sills suggests magma emplacement process through upward and outward propagation. Seismic-stratigraphic observations indicate that igneous activity occurred in the Early Cretaceous, Late Cretaceous and Paleogene corresponding to the timing of major azimuth changes observed in the Kane Oceanic fracture zone in the South Atlantic Ocean. Overall, our study, suggests a possible influence of plate boundary geodynamics on intra-plate magmatism as reflected in the link between the time of changes in the azimuth of oceanic fracture zones and magmatic emplacement observed in the tectono-stratigraphy of the intra-continental rift basins.

  10. Magma Emplacement and the 3D Geometry of Igneous Bodies in Rift Basins: Insights from the Bornu Basin, Onshore NE Nigeria

    NASA Astrophysics Data System (ADS)

    Suleiman, A. A.; Jackson, C. A. L.; Magee, C.; Fraser, A.

    2015-12-01

    Recent studies of regional unconformities in the circum-South Atlantic tectonic plates have linked unconformity age to the timing of changes in the azimuth of oceanic fracture zones, caused by plate interactions during opening of the South Atlantic. This observation is significant, proposing that a plate boundary geodynamic processes are transmitted into and expressed in plate interiors. However, it is not yet clear if and how other geologic events, such as intra-plate magmatism, may be linked to changes in the oceanic fracture azimuthal geometry. Here we use 2D and 3D seismic reflection, geochemical, borehole datasets and outcrop observations from the Bornu Basin, one of several intra-continental rift basins located in NE Nigeria to constrain the 3D geometry of igneous bodies and magmatic emplacement processes. This allows us to link South Atlantic plate boundary geodynamics and magmatism in the surrounding continental rift basins. Seismic attributes, reflection intensity, relative acoustic impedance, were used to identify and map igneous intrusions. Saucer-shaped sills are the most common type of intrusion, although en-echelon sills, up to 1.4 km in length, were also identified. The 3D geometry of the sills reveals the detailed structural components like inner sill, inclined sheets and outer sill (Fig.1). A mapped bifurcating network of the sills suggests magma emplacement process through upward and outward propagation. Seismic-stratigraphic observations indicate that igneous activity occurred in the Early Cretaceous, Late Cretaceous and Paleogene corresponding to the timing of major azimuth changes observed in the Kane Oceanic fracture zone in the South Atlantic Ocean. Overall, our study, suggests a possible influence of plate boundary geodynamics on intra-plate magmatism as reflected in the link between the time of changes in the azimuth of oceanic fracture zones and magmatic emplacement observed in the tectono-stratigraphy of the intra-continental rift basins.

  11. Origin of the early Permian Wajilitag igneous complex and associated Fe-Ti oxide mineralization in the Tarim large igneous province, NW China

    NASA Astrophysics Data System (ADS)

    Cao, Jun; Wang, Christina Yan; Xing, Chang-Ming; Xu, Yi-Gang

    2014-04-01

    The Wajilitag igneous complex is part of the early Permian Tarim large igneous province in NW China, and is composed of a layered mafic-ultramafic intrusion and associated syenitic plutons. In order to better constrain its origin, and the conditions of associated Fe-Ti oxide mineralization, we carried out an integrated study of mineralogical, geochemical and Sr-Nd-Hf isotopic analyses on selected samples. The Wajilitag igneous rocks have an OIB-like compositional affinity, similar to the coeval mafic dykes in the Bachu region. The layered intrusion consists of olivine clinopyroxenite, coarse-grained clinopyroxenite, fine-grained clinopyroxenite and gabbro from the base upwards. Fe-Ti oxide ores are mainly hosted in fine-grained clinopyroxenite. Forsterite contents in olivines from the olivine clinopyroxenite range from 71 to 76 mol%, indicating crystallization from an evolved magma. Reconstructed composition of the parental magma of the layered intrusion is Fe-Ti-rich, similar to that of the Bachu mafic dykes. Syenite and quartz syenite plutons have ɛNd(t) values ranging from +1.4 to +2.9, identical to that for the layered intrusion. They may have formed by differentiation of underplated magmas at depth and subsequent fractional crystallization. Magnetites enclosed in olivines and clinopyroxenes have Cr2O3 contents higher than those interstitial to silicates in the layered intrusion. This suggests that the Cr-rich magnetite is an early crystallized phase, whereas interstitial magnetite may have accumulated from evolved Fe-Ti-rich melts that percolated through a crystal mush. Low V content in Cr-poor magnetite (<6600 ppm) is consistent with an estimate of oxygen fugacity of FMQ + 1.1 to FMQ + 3.5. We propose that accumulation of Fe-Ti oxides during the late stage of magmatic differentiation may have followed crystallization of Fe-Ti-melt under high fO2 and a volatile-rich condition.

  12. Paleozoic and Paleoproterozoic Zircon in Igneous Xenoliths Assimilated at Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bacon, C. R.; Vazquez, J. A.; Wooden, J. L.

    2010-12-01

    Historically active Redoubt Volcano is a basalt-to-dacite cone constructed upon the Jurassic-early Tertiary Alaska-Aleutian Range batholith. New SHRIMP-RG U-Pb age and trace-element concentration results for zircons from gabbroic xenoliths and crystal-rich andesitic mush from a late Pleistocene pyroclastic deposit indicate that ~310 Ma and ~1865 Ma igneous rocks underlie Redoubt at depth. Two gabbros have sharply terminated prismatic zircons that yield ages of ~310 Ma. Zircons from a crystal mush sample are overwhelmingly ~1865 Ma and appear rounded due to incomplete dissolution. Binary plots of element concentrations or ratios show clustering of data for ~310-Ma grains and markedly coherent trends for ~1865-Ma grains; e.g., ~310-Ma grains have higher Eu/Eu* than most of the ~1865-Ma grains, the majority of which form a narrow band of decreasing Eu/Eu* with increasing Hf content which suggests that ~1865-Ma zircons come from igneous source rocks. It is very unlikely that detrital zircons from a metasedimentary rock would have this level of homogeneity in age and composition. One gabbro contains abundant ~1865 Ma igneous zircons, ~300-310 Ma fluid-precipitated zircons characterized by very low U and Th concentrations and Th/U ratios, and uncommon ~100 Ma zircons. We propose that (1) ~310 Ma gabbro xenoliths from Redoubt Volcano belong to the same family of plutons dated by Aleinikoff et al. (USGS Circular 1016, 1988) and Gardner et al. (Geology, 1988) located ≥500 km to the northeast in basement rocks of the Wrangellia and Alexander terranes and (2) ~1865 Ma zircons are inherited from igneous rock, potentially from a continental fragment that possibly correlates with the Fort Simpson terrane or Great Bear magmatic zone of the Wopmay Orogen of northwestern Laurentia. Possibly, elements of these Paleoproterozoic terranes intersected the Paleozoic North American continental margin where they may have formed a component of the basement to the Wrangellia

  13. Experimental Studies of Selected Aqueous Electrochemical Systems Relevant for Materials Processing in the Fabrications of Microelectronic Components and Direct Alcohol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Shi, Xingzhao

    A broad range of electrochemical techniques are employed in this dissertation to investigate a selected set of aqueous electrochemical systems that are relevant for materials processing in the fabrication of microelectronic devices and direct alcohol fuel cells. In terms of technical applications, this work covers three main experimental systems: (i) chemical mechanical planarization (CMP), (ii) electro-less nickel deposition, and (iii) direct alkaline glycerol fuel cells. The first two areas are related to electronic device fabrications and the third topic is related to cost-effective energy conversion. The common electrochemical aspect of these different systems is that, in all these cases the active material characteristics are governed by complex (often multi-step) reactions occurring at metal-liquid (aqueous) interfaces. Electro-analytical techniques are ideally suited for studying the detailed mechanisms of such reactions, and the present investigation is largely focused on developing adequate analytical strategies for probing these reaction mechanisms. In the fabrication of integrated circuits, certain steps of materials processing involve CMP of Al deposited on thin layers of diffusion barrier materials like Ta/TaN, Co, or Ti/TiN. A specific example of this situation is found in the processing of replacement metal gates used for high-k/metal-gate transistors. Since the commonly used barrier materials are nobler than Al, the Al interface in contact with the barrier can become prone to galvanic corrosion in the wet CMP environment. Using model systems of coupon electrodes and two specific barrier metals, Ta and Co, the electrochemical factors responsible for these corrosion effects are investigated here in a moderately acidic (pH = 4.0) abrasive-free solution. The techniques of cyclic voltammetry and impedance spectroscopy are combined with strategic measurements of galvanic currents and open circuit potentials (OCPs). L-ascorbic acid (AA) is employed as a

  14. Microstructure, shear modulus and attenuation in igneous rocks approaching melting at seismic frequencies

    NASA Astrophysics Data System (ADS)

    Chien, S.; Redfern, S. A.

    2010-12-01

    Melt-related attenuation mechanisms, such as viscous flow and squirt processes, are of paramount importance in understanding high seismic wave attenuation in partially molten regions of the deep Earth. Strong temperature dependence of the anelastic quality factor, Q, is one obvious consequence of such mechanisms. Mineralogical composition, grain size, melt viscosity and microstructure (morphology and size of the inter-granular pores/micro-cracks), are important parameters for modeling attenuation mechanisms, and are control rock properties, particularly in the partially molten rocks. There have been many theoretical studies linking creep or viscosity models and laboratory experiments for partially molten rocks. However, experimental data on the relationship between temperature and attenuation remains. In this study, the shear modulus (G) and inverse quality factor (1/Q) of two igneous rocks (gabbro and basalt) were measured in the laboratory at temperatures approaching the melting point using the inverted forced torsion pendulum. Attenuation increases exponentially when shear modulus drops rapidly towards to melting temperature in both gabbro (1400 K) and basalt (1250 K). For measurements conducted using cyclic shear stresses at 1Hz, two attenuation relaxation peaks are found in gabbro at 1214 K and 1410 K, while only one attenuation relaxation peak occurs in basalt at 1151 K. These attenuation peaks may result from grain boundary sliding, diffusion creep and/or melt squirt. In addition to the relaxation peaks, there is a rising exponential increase in attenuation approaching the melting point from below. A power law model has been used to determine the effective activation energy associated with this high-temperature attenuation background. An activation energy of 68 kJ/mole in basalt and 882 kJ/mole in gabbro is found. The result for gabbro is in a good agreement with the study of Fontaine et al. in 2005 (873 kJ/mol), and the very different behaviour of basalt

  15. Magma storage of an alkali ultramafic igneous suite from Chamberlindalen, SW Svalbard

    NASA Astrophysics Data System (ADS)

    Gołuchowska, Karolina; Barker, Abigail K.; Czerny, Jerzy; Majka, Jarosław; Manecki, Maciej; Farajewicz, Milena; Dwornik, Maciej

    2016-02-01

    An alkali mafic-ultramafic igneous suite of composite intrusions, lenses and associated greenstones are hosted by Neoproterozoic metasedimentary sequences in Chamberlindalen, Southwest Svalbard. This study focuses on the alkali igneous suite of Chamberlindalen with a view to determining the conditions of magma storage. The rocks from Chamberlindalen display cumulate textures, are highly magnesian and are classified as alkaline by the occurrence of kaersutite. They have textures that indicate cocrystallization of primary magmatic minerals such as diopside, kaersutite-ferrokaersutite and biotite-phlogopite in different proportions. The historic magma plumbing system for the alkaline cumulates has been reconstructed by thermobarometry. Diopside and kaersutite crystallization in the alkaline cumulates show a dominant level of magma storage between 30 and 50 km in the subcontinental lithospheric mantle.

  16. Mantle origin of the Emeishan large igneous province from an analysis of residual gravity anomalies

    NASA Astrophysics Data System (ADS)

    Deng, Y.; Zhang, Z.; Mooney, W. D.; Fan, W.; Zhong, Q.; Badal, J.

    2013-12-01

    The Emeishan large igneous province (ELIP) is the only verified large igneous province in China. It covers an area of 250,000 km2 from the eastern margin of the Tibetan Plateau to the western margin of the Yangtze block. Most studies on ELIP are from geochemistry and tectonics, but the deep origin of the ELIP is still unclear. In this study, we investigate the residual gravity anomaly in South China and its relationship to the Emeishan large igneous province with constrains of lithospheric structure from deep seismic sounding profiles, deep seismic reflection surveys, and a variety of broadband seismic observations acquired in South China in the last several decades. Our working scheme consists of removing the respective gravitational effects due to: (1) the sediments, and undulations of the (2) crystalline basement, (3) upper crust; (4) Moho and (5) lithospheric thickness. We have thus obtained the residual gravity anomaly of the ELIP and surrounding region, striking positive residual anomaly with maximum value of 140 mGal is observed at the ELIP region. We use the conjugate gradient method to locate the deep origins of the residual gravity data. As a result, our preferred model consists of a positive cylindrical density anomaly that provides a fit to the residual gravity anomaly observed in ELIP. As the distance increases from the inner zone of the ELIP to the outer zone, the positive residual gravity decreases. Hence, in our model, the density anomaly decreases from about 0.06 g/cm3 beneath the inner zone to about 0.03 g/cm3 beneath the outer zone. The residual gravity and our preferred density anomaly provide new evidence, along with the seismic data and geochemical data, to confirm the domal structure of the Permian mantle plume that gave rise to the Emenshan Large Igneous Province.

  17. Floor-fractured crater models for igneous crater modification on Venus

    NASA Technical Reports Server (NTRS)

    Wichman, R. W.; Schultz, P. H.

    1992-01-01

    Although crater modification on the Earth, Moon, and Mars results from surface erosion and crater infilling, a significant number of craters on the Moon also exhibit distinctive patterns of crater-centered fracturing and volcanism that can be modeled as the result of igneous crater modification. Here, we consider the possible effects of Venus surface conditions on this model, describe two examples of such crater modification, and then briefly discuss the constraints these craters place on conditions at depth.

  18. Termination time of peak decratonization in North China: Geochemical evidence from mafic igneous rocks

    NASA Astrophysics Data System (ADS)

    Dai, Li-Qun; Zheng, Yong-Fei; Zhao, Zi-Fu

    2016-01-01

    Geophysical and petrological data indicate destruction of the cratonic lithosphere in North China in the Mesozoic, resulting in replacement of the ancient subcontinental lithospheric mantle (SCLM) by the juvenile SCLM. However, it remains to be answered when the craton destruction would have been terminated in the Mesozoic. This question is resolved by studying the two types of mafic igneous rocks with contrasting geochemical compositions from North China. The first type of mafic igneous rock shows arc-like trace element distribution patterns and enriched radiogenic Sr-Nd isotope compositions, with emplacement ages spanning from the Triassic to Early Cretaceous. The mafic magmatism is absent in a period from ~ 200 Ma to ~ 135 Ma, recording the thinning of cratonic lithosphere due to the westward flat subduction of the Paleo-Pacific slab beneath the North China Craton. In contrast, the second type of mafic igneous rocks exhibits oceanic island basalts (OIB)-like trace element distribution patterns and relatively depleted radiogenic Sr-Nd isotope compositions, with emplacement ages spanning from the Early Cretaceous to Cenozoic. Zircon U-Pb dating yields an age of ~ 121 Ma for the geochemical transformation between the two types of mafic igneous rocks. This age marks a dramatic demarcation in the composition of their mantle sources. As such, the nature of mantle lithosphere in North China was changed from the ancient SCLM to the juvenile SCLM at ~ 121 Ma. Thus, this age not only signifies the tectonic transition from the enriched mantle to the depleted mantle in the Early Cretaceous, but also dates the termination of peak decratonization in North China. Therefore, the craton destruction in the Early Cretaceous is temporally and spatially associated with the dramatic changes in the geochemical composition of mantle lithosphere.

  19. Lithospheric mantle evolution monitored by overlapping large igneous provinces: Case study in southern Africa

    NASA Astrophysics Data System (ADS)

    Jourdan, F.; Bertrand, H.; Féraud, G.; Le Gall, B.; Watkeys, M. K.

    2009-02-01

    Most of the studies on the large igneous provinces (LIPs) focus on Phanerozoic times, and in particular, those related to the disruption of Pangea (e.g. CAMP, Karoo, Parana-Etendeka) while Precambrian LIPs (e.g. Ventersdorpf, Fortescue) remain less studied. Although the investigation of Precambrian LIPs is difficult because they are relatively poorly preserved, assessment of their geochemical characteristics in parallel with younger overlapping LIP is fundamental for monitoring the evolution of the mantle composition through time. Recent 40Ar/ 39Ar dating of the Okavango giant dyke swarm (and related sills) in southern Africa showed that ~ 90% of the dykes were emplaced at 179 ± 1 Ma and belong to the Karoo large igneous province whereas ~ 10% of dykes yielded Proterozoic ages (~ 1-1.1 Ga). Here, we provide new major, trace and rare earth elements analyses of the low-Ti Proterozoic Okavango dyke swarm (PODS) that suggest, combined with age data, a cognate origin with the 1.1 Ga Umkondo large igneous province (UIP), southern Africa. The geochemical characteristics of the PODS and UIP basalts are comparable to those of overlapping low-Ti Karoo basalts, and suggest that both LIPs were derived from similar enriched mantle sources. A mantle plume origin for these LIPs is not easily reconciled with the geochemical dataset and the coincidence of two compositionally similar mantle plumes acting 900 Myr apart is unlikely. Instead, we propose that the Umkondo and Karoo large igneous provinces monitored the slight evolution of a shallow enriched lithospheric mantle from Proterozoic to Jurassic.

  20. Experimental Studies of Selected Aqueous Electrochemical Systems Relevant for Materials Processing in the Fabrications of Microelectronic Components and Direct Alcohol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Shi, Xingzhao

    A broad range of electrochemical techniques are employed in this dissertation to investigate a selected set of aqueous electrochemical systems that are relevant for materials processing in the fabrication of microelectronic devices and direct alcohol fuel cells. In terms of technical applications, this work covers three main experimental systems: (i) chemical mechanical planarization (CMP), (ii) electro-less nickel deposition, and (iii) direct alkaline glycerol fuel cells. The first two areas are related to electronic device fabrications and the third topic is related to cost-effective energy conversion. The common electrochemical aspect of these different systems is that, in all these cases the active material characteristics are governed by complex (often multi-step) reactions occurring at metal-liquid (aqueous) interfaces. Electro-analytical techniques are ideally suited for studying the detailed mechanisms of such reactions, and the present investigation is largely focused on developing adequate analytical strategies for probing these reaction mechanisms. In the fabrication of integrated circuits, certain steps of materials processing involve CMP of Al deposited on thin layers of diffusion barrier materials like Ta/TaN, Co, or Ti/TiN. A specific example of this situation is found in the processing of replacement metal gates used for high-k/metal-gate transistors. Since the commonly used barrier materials are nobler than Al, the Al interface in contact with the barrier can become prone to galvanic corrosion in the wet CMP environment. Using model systems of coupon electrodes and two specific barrier metals, Ta and Co, the electrochemical factors responsible for these corrosion effects are investigated here in a moderately acidic (pH = 4.0) abrasive-free solution. The techniques of cyclic voltammetry and impedance spectroscopy are combined with strategic measurements of galvanic currents and open circuit potentials (OCPs). L-ascorbic acid (AA) is employed as a

  1. Geochronology and geochemistry of Early Cretaceous igneous units from the central Sulu orogenic belt: Evidence for crustal delamination during a shift in the regional tectonic regime

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Chang, Su-Chin; Wang, Kuo-Lung; Lu, Hong-Bo; Zhang, Hai-Chun

    2015-11-01

    Widespread Late Mesozoic igneous events in northern China have been intensively investigated over the past decades and provide evidence for regional lithospheric thinning. The underlying mechanism causing lithospheric thinning remains unclear however. This study reports U-Pb zircon ages, geochemical data and isotopic ratios for Cretaceous igneous units from the central Sulu orogenic belt as it occurs in the Shandong Peninsula. LA-ICP-MS U-Pb analyses of magmatic zircons identified a relatively restricted population of ages ranging from 123 ± 2 Ma to 120 ± 2 Ma from four representative samples of igneous units in the study area. Geochemical analysis of the samples revealed LREE and LILE enrichment, HREE depletion, high initial 87Sr/86Sr values ranging from 0.7040 to 0.7096, and low negative εNd(t) values from -22.0 to -12.2. The data suggest lamprophyres derived separately from heterogeneous mantle inputs, which experienced crust-mantle interaction, andesitic porphyrites and syenogranites derived from enriched lithospheric mantle and rhyolites derived from partial melting of an ancient crustal component. Assimilation and fractionation processes did not contribute to lamprophyre formation, but did play an important role in generating andesitic porphyrites, syenogranites and rhyolites. The petrogenetic history of these rocks indicates intensive lithospheric thinning of the upper mantle and lower crust beneath the Sulu orogenic belt at 123-120 Ma. Given the timing and regional tectonic framework in which these units formed, thinning was likely caused by an abrupt change in the direction of the subducting Pacific plate.

  2. Ages of igneous and hydrothermal events in the Round Mountain and Manhattan gold districts, Nye County, Nevada.

    USGS Publications Warehouse

    Shawe, D.R.; Marvin, R.F.; Andriessen, P.A.M.; Mehnert, H.H.; Merritt, V.M.

    1986-01-01

    Isotopic age determinations of rocks and minerals separated from them are applied to refining and correlating the geological history of igneous and mineralizing events in a part of the Basin and Range province. -G.J.N.

  3. The Anisotropy of Magnetic Susceptibility of Igneous Rocks: Lessons From Obsidians and Pyroclastic Deposits

    NASA Astrophysics Data System (ADS)

    Canon-Tapia, E.

    2013-05-01

    The anisotropy of magnetic susceptibility (AMS) of igneous rocks differs from that of other lithologies in several aspects that are related to their characteristics of emplacement history. Nevertheless, within the group of igneous rocks there are also differences on emplacement mechanisms that can lead to specific and distinctive AMS signatures. In this work, a review of the most important emplacement regimes is made, paying special attention to the extreme conditions represented by obsidians and pyroclastic deposits. These two extreme emplacement regimes are controlled mainly by the viscosity of the fluid phase, but the differences in AMS signatures also includes other differences in the nature of the ferromagnetic grains that are present in the rocks during emplacement. For example, the results of this work indicate that the AMS can be associated to a population of ferromagnetic minerals of a submicroscopic size, despite of which it can be very well defined and yield large degrees of anisotropy. It is suggested that the AMS associated to such population of small grains might indeed be the origin of the AMS of other igneous rocks that have an optically observable fraction of mineral grains, although until present it had been overlooked in most instances. As it had been suggested before, use of tests designed to identify the contribution of a superparamagnetic fraction (SP) in the magnetic properties of a rock can help us to identify the presence of such a SP-related AMS in other cases.

  4. Classification Scheme for Diverse Sedimentary and Igneous Rocks Encountered by MSL in Gale Crater

    NASA Technical Reports Server (NTRS)

    Schmidt, M. E.; Mangold, N.; Fisk, M.; Forni, O.; McLennan, S.; Ming, D. W.; Sumner, D.; Sautter, V.; Williams, A. J.; Gellert, R.

    2015-01-01

    The Curiosity Rover landed in a lithologically and geochemically diverse region of Mars. We present a recommended rock classification framework based on terrestrial schemes, and adapted for the imaging and analytical capabilities of MSL as well as for rock types distinctive to Mars (e.g., high Fe sediments). After interpreting rock origin from textures, i.e., sedimentary (clastic, bedded), igneous (porphyritic, glassy), or unknown, the overall classification procedure (Fig 1) involves: (1) the characterization of rock type according to grain size and texture; (2) the assignment of geochemical modifiers according to Figs 3 and 4; and if applicable, in depth study of (3) mineralogy and (4) geologic/stratigraphic context. Sedimentary rock types are assigned by measuring grains in the best available resolution image (Table 1) and classifying according to the coarsest resolvable grains as conglomerate/breccia, (coarse, medium, or fine) sandstone, silt-stone, or mudstone. If grains are not resolvable in MAHLI images, grains in the rock are assumed to be silt sized or smaller than surface dust particles. Rocks with low color contrast contrast between grains (e.g., Dismal Lakes, sol 304) are classified according to minimum size of apparent grains from surface roughness or shadows outlining apparent grains. Igneous rocks are described as intrusive or extrusive depending on crystal size and fabric. Igneous textures may be described as granular, porphyritic, phaneritic, aphyric, or glassy depending on crystal size. Further descriptors may include terms such as vesicular or cumulate textures.

  5. Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion

    SciTech Connect

    D.S. Kimball; C.E. Sanders

    2006-02-07

    The Department of Energy (DOE) is currently preparing an application to submit to the U.S. Nuclear Regulatory Commission for a construction authorization for a monitored geologic repository. The repository will contain spent nuclear fuel (SNF) and defense high-level waste (DHLW) in waste packages placed in underground tunnels, or drifts. The primary objective of this paper is to perform a criticality analysis for waste packages containing DOE SNF affected by a disruptive igneous intrusion event in the emplacement drifts. The waste packages feature one DOE SNF canister placed in the center and surrounded by five High-Level Waste (HLW) glass canisters. The effective neutron multiplication factor (k{sub eff}) is determined for potential configurations of the waste package during and after an intrusive igneous event. Due to the complexity of the potential scenarios following an igneous intrusion, finding conservative and bounding configurations with respect to criticality requires some additional considerations. In particular, the geometry of a slumped and damaged waste package must be examined, drift conditions must be modeled over a range of parameters, and the chemical degradation of DOE SNF and waste package materials must be considered for the expected high temperatures. The secondary intent of this calculation is to present a method for selecting conservative and bounding configurations for a wide range of end conditions.

  6. Voluminous silicic eruptions during late Permian Emeishan igneous province and link to climate cooling

    NASA Astrophysics Data System (ADS)

    Yang, Jianghai; Cawood, Peter A.; Du, Yuansheng

    2015-12-01

    Silicic eruptive units can constitute a substantive component in flood-basalts-dominated large igneous provinces, but usually constitute only a small proportion of the preserved volume due to poor preservation. Thus, their environmental impact can be underestimated or ignored. Establishing the original volume and potential climate-sensitive gas emissions of silicic eruptions is generally lacking for most large igneous provinces. We present a case study for the ˜260 Ma Emeishan province, where silicic volcanic rocks are a very minor component of the preserved rock archive due to extensive erosion during the Late Permian. Modal and geochemical data from Late Permian sandstones derived from the province suggest that silicic volcanic rocks constituted some ˜30% by volume of the total eroded Emeishan volcanic source rocks. This volume corresponds to > 3 ×104 km3 on the basis of two independent estimate methods. Detrital zircon trace element and Hf isotopic data require the silicic source rocks to be formed mainly by fractional crystallization from associated basaltic magmas. Based on experimental and theoretical calculations, these basalt-derived ˜104 km3 silicic eruptions released ˜1017 g sulfur gases into the higher atmosphere and contribute to the contemporaneous climate cooling at the Capitanian-Wuchiapingian transition (˜260 Ma). This study highlights the potentially important impact on climate of silicic eruptions associated with large igneous province volcanism.

  7. Testing Models for the Origin of the Paraná-Etendeka Igneous Province

    NASA Astrophysics Data System (ADS)

    Foulger, G. R.

    2015-12-01

    The Paraná-Etendeka igneous province and associated magmatism, including the Walvis Ridge, the Tristan da Cunha archipelago, and the Rio Grande Rise, has been variously attributed to passive response to intraplate extension or to a deep-mantle plume postulated to currently underlie the island of Tristan da Cunha. The volcanic region is one of only three in the world where a Large Igneous Province is associated with subsequent time-progressive volcanism. Multi-disciplinary methods have been applied to test the various hypotheses for its genesis. These include study of the vertical crustal motions precursory to flood volcanism, the spatial distribution and time-history of volcanism, the synchronous deformation and volcanism in the adjacent African and South American plates, the fabric of the sea floor, the seismic structure of the mantle, and the geochemical composition of the lavas. Models inspired by the huge array of observational data available have been further explored using numerical modeling of mantle convection. In this paper I shall review data and models that bear on the formation of the Paraná-Etendeka igneous province, and discuss ways to interpret and test them.

  8. Earthdata Search: The Relevance of Relevance

    NASA Technical Reports Server (NTRS)

    Quinn, Patrick

    2016-01-01

    Through recent usability studies, the issue of relevance became increasingly clear in the Earthdata Search Client. After all, if a user can't find the data they are looking for, nothing else we do matters. This presentation walks through usability testing findings and recent relevance improvements made to the Earthdata Search Client.

  9. Igneous History of the Andean Cordillera and Patagonian Plateau around Latitude 46 degrees S

    NASA Astrophysics Data System (ADS)

    Baker, P. E.; Rea, W. J.; Skarmeta, J.; Caminos, R.; Rex, D. C.

    1981-11-01

    From the Middle Jurassic onwards persistent igneous activity in the southern Andes around 46 degrees S was controlled by easterly dipping subduction along the Pacific margin. Cogenetic plutonic rocks belonging to the Patagonian batholith, and calc-alkaline volcanics ranging from basaltic andesites to rhyolitic tuffs and ignimbrites are the principal products. Erosion of the primary volcanics has led at various times to the development of thick volcaniclastic sequences, for example in the Cretaceous--Lower Tertiary Divisadero formation. The Coyhaique region marks the northerly extension of a narrow back-arc basin in which the marine Neocomian successions accumulated. Volcaniclastics from the island arc, which presumably lay to the west, are intercalated with the sediments. Although the marine basin was short-lived a mildly extensional back-arc regime may have existed through much of Mesozoic--Recent times. Widespread basalt--rhyolite volcanism on the eastern side of the cordillera seems to have been associated with this tectonic environment. Remnants of the Patagonian basalt plateau at latitude 45-47 degrees S extend from the Argentine--Chile frontier to Lago Colhue Huapi. Four principal age and compositional groups have been distinguished in the lavas. (i) The oldest, which are about 80 Ma, occur in sections at Senguerr and Morro Negro. They are almost exclusively tholeiitic, but show some calc-alkaline affinities and resemble in other respects basalts from marginal basins. (ii) The second group (57-43 Ma) occur in the lower part of the Chile Chico section with a compositional spread from olivine tholeiites through alkali basalts to one occurrence of a basanite. (iii) The upper part of the main plateau sequence, where the flows are in the range 25-9 Ma, are dominantly of alkali basalt composition. (iv) Post-plateau flows from small cinder cones on the surface of the plateau range in age from ca. 4 Ma to 0.2 Ma or less. They are mostly highly undersaturated

  10. The Karoo igneous province — A problem area for inferring tectonic setting from basalt geochemistry

    NASA Astrophysics Data System (ADS)

    Duncan, Andrew R.

    1987-06-01

    Tholeiitic basalts and associated intrusives are the major component of the Karoo igneous province. They are of Mesozoic age and constitute one of the world's classic continental flood basalt (CFB) provinces. It has been argued that most Karoo basalts have not undergone significant contamination with continental crust and that their lithospheric mantle source areas were enriched in incompatible minor and trace elements during the Proterozoic. The only exceptions to this are late-stage MORB-like dolerites near the present-day continental margins which are considered to be of asthenospheric origin. When data for the "southern" Karoo basalts are plotted on many of the geochemical discriminant diagrams which have been used to infer tectonic setting, essentially all of them would be classified as calc-alkali basalts (CAB's) or low-K tholeiites. Virtually none of them plot in the compositional fields designated as characteristic of "within-plate" basalts. There is little likelihood that the compositions of the Karoo basalts can be controlled by active subduction at the time of their eruption and no convincing evidence that a "subduction component" has been added to the subcontinental lithospheric mantle under the entire area in which the basalts crop out. It must be concluded that the mantle source areas for CAB's and the southern Karoo basalts have marked similarities. In contrast, the data for "northern" Karoo basalts largely plot in the "within-plate" field on geochemical discriminant diagrams. Available data suggest that the source composition and/or the restite mineralogy and degree of partial melting are different for southern and northern Karoo basalts. There is no evidence for any difference in tectonic setting between the southern and northern Karoo basalts at the time they were erupted. This appears to be clear evidence that specific mantle source characteristics and/or magmatic processes can vary within a single CFB province to an extent that renders at least

  11. Distribution of fluid inclusions in igneous quartz of the Capitan pluton, New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Ratajeski, Kent; Campbell, Andrew R.

    1994-02-01

    Fluid inclusions in granites have been used extensively in studies of magmatic-hydrothermal processes, but few studies have documented the distribution of secondary fluid inclusions within the nonmineralized main body of an intrusion. Previous work on fluid inclusions in Th-U-REE quartz/ fluorite vein deposits in the Capitan pluton suggests that these veins resulted from high-temperature, high-salinity, magmatic fluids in fractured and brecciated zones in the cooled outer carapace of the pluton. Petrographic examination of phenocryst quartz in forty-four thin sections of granite from the Capitan pluton reveals that these same fluids are found in secondary fluid inclusions. Fluid inclusions with daughter minerals commonly occur in the outer granophyre and aplite zones, but are usually absent in the porphyritic core. Microthermometric data and calculated salinities from fifty-eight fluid inclusions in phenocryst quartz and thirty-one fluid inclusions in miarolitic quartz (both samples taken from the granophyre zone) also correlate fairly well with the data from the Th-U-REE quartz/fluorite vein deposits, and similar types of fluid inclusions are found in all three occurrences of quartz. A major difference, however, is that vapor-rich inclusions, abundant as secondary inclusions in igneous phenocryst quartz, are extremely scarce in the vein quartz. Liquid-vapor homogenization temperatures of high-salinity inclusions in phenocryst quartz range from 204-509°C with an average of 384°C. Halite dissolution temperatures of high salinity inclusions range from 442-583°C with an average of 525°C. Total homogenization temperatures are not as well documented due to decrepitation of many of the high salinity inclusions before total homogenization. Samples of miarolitic quartz appear to contain more low-salinity fluid inclusions than the phenocryst quartz, but high-salinity inclusions are present as well. These observations suggest that the magmatic-hydrothermal fluids

  12. Source of Mesozoic intermediate-felsic igneous rocks in the North China craton: Granulite xenolith evidence

    NASA Astrophysics Data System (ADS)

    Jiang, Neng; Carlson, Richard W.; Guo, Jinhui

    2011-07-01

    Four intermediate to felsic igneous rocks from the Zhangjiakou region, along the northern margin of the North China craton, have magmatic zircon U-Pb ages from 122 to 144 Ma. Two of these samples have inherited zircon U-Pb ages of ~ 2.5 Ga, similar to the zircon ages of rocks from the surrounding granulite terrain. Zircons from two intermediate composition granulite xenoliths (JN0811 and JN0919) in the nearby Cenozoic Hannuoba basalts yield two groups of ages. The rims have concordant Mesozoic ages mostly between 120 and 145 Ma, coeval with the Mesozoic intermediate-felsic magmatism in the region, while the cores have discordant U-Pb ages with upper-intercepts of ~ 2.5 Ga, overlapping the zircon ages of granulite terrain rocks, and lower-intercept ages of ~ 130 Ma, approximating the ages of the Mesozoic intermediate-felsic magmatism. The Sr-Nd isotopic compositions of the Mesozoic intermediate-felsic igneous rocks are completely different from those expected for basaltic melts from either the lithospheric mantle or the asthenospheric mantle, precluding a derivation by extensive fractional crystallization of mantle-derived magmas. The lack of correlation between (86Sr/87Sr)i, εNd(t) and SiO2 for the Mesozoic igneous rocks, the very narrow range of zircon εHf(t) for individual intermediate-felsic igneous rocks, and simple binary mixing calculations argue against them being formed by mixing between mantle-derived magma and preexisting crust that has extremely evolved Sr-Nd isotopic compositions like granulite xenoliths JN0811 and JN0919. Hf isotopic compositions of the Mesozoic zircons and whole-rock geochemistry show that the granulite xenoliths with extremely evolved Sr-Nd isotopic compositions have not undergone partial melting during the Mesozoic and thus do not contribute to the Mesozoic intermediate-felsic magmas. Further comparisons show that the source rocks for the Mesozoic intermediate-felsic magmas likely were late Archean lower crustal rocks similar in

  13. A Study to Determine the Skills and Knowledges Required for Personnel in Business Data Processing Centers to Develop a Relevant Curriculum for Secondary Data Processing Programs and for Data Processing Programs in Teacher Education.

    ERIC Educational Resources Information Center

    Cannon, Francis R.; And Others

    To give those business and vocational educators involved in curriculum development a better understanding of data processing personnel requirements, a study was initiated to determine the status of data processing equipment and personnel in selected Pennsylvania businesses. Following a literature review, a questionnaire was developed, revised, and…

  14. Igneous composition vaiations determined by ChemCam along Curiosity's traverse from Bradbury to Rocknest area at Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Sautter, Violaine; MSL Science Team

    2013-04-01

    , defined by bedded and light toned fractured rocks characteristic of the Glenelg-Yellowknife bay area. It is characterized by stratified outcrops where layered dark rocks alternate with light-toned cross-bedded units. Throughout these strata the rocks appear significantly finer grained compared to zone I. They may show sandstone-like texture (Bathurst Inlet) and vesicular to laminated morphology. Aeolian ripples replace gravels. Textural changes in the rocks translate chemically to compositions that are lower in Si and Al, and higher in Fe and K compared to zone I, consistent with under-saturated basaltic compositions close to basanite. Zone II is rather complex, showing evidence of lava flows on one hand and ambiguous rock textures on the other hand. The latter may be interpreted as lithification of sediments from an igneous source corresponding either to some explosive type of volcanism or deriving from complex sedimentary processes. In conclusion zone I appears to reveal feldspar-rich crustal bedrock for the first time on Mars, which may come the crater rim. Zone II, dominated by iron- and potassium-rich undersaturated basaltic compositions, result from a complex sequence of processes not yet fully understood.

  15. Influence of Landscape Morphology and Vegetation Cover on the Sampling of Mixed Igneous Bodies

    NASA Astrophysics Data System (ADS)

    Perugini, Diego; Petrelli, Maurizio; Poli, Giampiero

    2010-05-01

    A plethora of evidence indicates that magma mixing processes can take place at any evolutionary stage of magmatic systems and that they are extremely common in both plutonic and volcanic environments (e.g. Bateman, 1995). Furthermore, recent studies have shown that the magma mixing process is governed by chaotic dynamics whose evolution in space and time generates complex compositional patterns that can span several length scales producing fractal domains (e.g. Perugini et al., 2003). The fact that magma mixing processes can produce igneous bodies exhibiting a large compositional complexity brings up the key question about the potential pitfalls that may be associated with the sampling of these systems for petrological studies. In particular, since commonly only exiguous portions of the whole magmatic system are available as outcrops for sampling, it is important to address the point whether the sampling may be considered representative of the complexity of the magmatic system. We attempt to address this crucial point by performing numerical simulations of chaotic magma mixing processes in 3D. The numerical system used in the simulations is the so-called ABC (Arnold-Beltrami-Childress) flow (e.g. Galluccio and Vulpiani, 1994), which is able to generate the contemporaneous occurrence of chaotic and regular streamlines in which the mixing efficiency is differently modulated. This numerical system has already been successfully utilized as a kinematic template to reproduce magma mixing structures observed on natural outcrops (Perugini et al., 2007). The best conditions for sampling are evaluated considering different landscape morphologies and percentages of vegetation cover. In particular, synthetic landscapes with different degree of roughness are numerically reproduced using the Random Mid-point Displacement Method (RMDM; e.g. Fournier et al., 1982) in two dimensions and superimposed to the compositional fields generated by the magma mixing simulation. Vegetation

  16. Silicon Isotope Fractionation During Acid Water-Igneous Rock Interaction

    NASA Astrophysics Data System (ADS)

    van den Boorn, S. H.; van Bergen, M. J.; Vroon, P. Z.

    2007-12-01

    ), the &δ&&30Si value of dissolved silicon in the lake water must be even higher. We infer that progressive cation removal alone is inadequate to describe rock dissolution and silicification by acid fluid. Exchange of silicon between the solution and mineral phases probably accompanied the alteration process. This hypothesis is qualitatively consistent with the idea that elements in solution take part in the formation of altered silica-rich layers at mineral-solution interfaces, as invoked to interpret surface reactions during silicate mineral weathering (e.g., Adriaens et al., 1999; Hellmann et al., 2003). References Adriaens et al., 1999. Surf. Interface Anal., 27: 8-23 Basile-Doelsch et al., 2006. Nature, 433: 399-402. Hellmann et al., 2003. Phys. Chem. Minerals, 30: 192-197.

  17. Astrophysics of CAI formation as revealed by silicon isotope LA-MC-ICPMS of an igneous CAI

    NASA Astrophysics Data System (ADS)

    Shahar, Anat; Young, Edward D.

    2007-05-01

    Silicon isotope ratios of a typical CAI from the Leoville carbonaceous chondrite, obtained in situ by laser ablation MC-ICPMS, together with existing 25Mg/ 24Mg data, reveal a detailed picture of the astrophysical setting of CAI melting and subsequent heating. Models for the chemical and isotopic effects of evaporation of the molten CAI are used to produce a univariant relationship between PH 2 and time during melting. The result shows that this CAI was molten for a cumulative time of no more than 70 days and probably less than 15 days depending on temperature. The object could have been molten for an integrated time of just a few hours if isotope ratio zoning was eliminated after melting by high subsolidus temperatures (e.g., > 1300 K) for ˜ 500 yr. In all cases subsolidus heating sufficient to produce diffusion-limited isotope fractionation at the margin of the solidified CAI is required. These stable isotope data point to a two-stage history for this igneous CAI involving melting for a cumulative timescale of hours to months followed by subsolidus heating for years to hundreds of years. The thermobarometric history deduced from combining Si and Mg isotope ratio data implicates thermal processing in the disk, perhaps by passage through shockwaves, following melting. This study underscores the direct link between the meaning of stable isotope ratio zoning, or lack thereof, and the inferred astrophysical setting of melting and subsequent processing of CAIs.

  18. Geology and porphyry copper-type alteration-mineralization of igneous rocks at the Christmas Mine, Gila County, Arizona

    USGS Publications Warehouse

    Koski, Randolph A.

    1979-01-01

    igneous rocks is progressively more alkaline and silicic from basalt to granodiorite. Early (Stage I) chalcopyrite-bornite (-molybdenite) mineralization and genetically related K-silicate alteration are centered on the Christmas stock. K-silicate alteration is manifested by pervasive hornblende-destructive biotitization in the stock, biotitization of basaltic volcanic wall rocks, and a continuous stockwork of K-feldspar veinlets and quartz-K-feldspar veins in the stock and quartz-sulfide veins in volcanic rocks. Younger (Stage II) pyrite-chalcopyrite mineralization and quartz-sericite-chlorite alteration occur in a zone overlapping with but largely peripheral to the zone of Stage I stockwork veins. Within the Christmas intrusive complex, K-silicate-altered rocks in the central stock are flanked east and west by zones of fracture-controlled quartz-sericite alteration and strong pyritization. In volcanic rocks quartz-chlorite-pyrite-chalcopyrite veins are superimposed on earlier biotitization and crosscut Stage I quartz-sulfide veins. Beyond the zones of quartz-sericite alteration, biotite rhyodacite porphyry dikes contain the propylitic alteration assemblage epidote-chlorite-albite-sphene. Chemical analyses indicate the following changes during pervasive alteration of igneous rocks: (1) addition of Si, K, H, S, and Cu, and loss of Fe 3+ and Ca during intense biotitization of basalt; (2) loss of Na and Ca, increase of Fe3+/Fe2+, and strong H-metasomatism during sericitization of quartz diorite; and (3) increase in Ca, Na, and Fe3+/Fe2+, and loss of K during intense propylitization of biotite rhyodacite porphyry dikes. Thorough biotitization of biotite granodiorite porphyry in the Christmas stock was largely an isochemical process. Fluid-inclusion petrography reveals that Stage I veins are characterized by low to moderate populations of moderate-salinity and gas-rich inclusions, and sparse but ubiquitous halite-bearing inclusions. Moderate-salinity an

  19. Preservation of primary mineral inclusions and secondary mineralization in igneous zircon: a case study in orthogneiss from the Blue Ridge, Virginia

    NASA Astrophysics Data System (ADS)

    Bell, Elizabeth A.

    2016-03-01

    A wide variety of minerals occur as inclusions in igneous zircon and can provide valuable evidence of source magma composition from originally magmatic zircons in metamorphic and clastic sedimentary rocks. However, it is not clear the extent to which zircons preserve the primary composition of their inclusions through a variety of geologic processes. This paper documents a case study of inclusion-rich, originally igneous zircon from an orthogneiss in the Blue Ridge of southwest Virginia. Zircon inclusions isolated from cracks contain 4 % clearly metamorphic phases (mainly in hosts with disturbed U-Pb systems) and otherwise retain distinct plagioclase chemistry, K-feldspar/plagioclase pairs, and biotite with much wider-ranging Mg/(Mg + Fe) than biotite in the rock matrix. A clearly secondary mineralization suite filling cracks in the zircons consists of quartz, biotite, albite, and epidote. Overall, these zircons preserve mineral inclusions distinct from their current host rock (except when exposed to external environments via cracks), demonstrating that non-metamict zircons may preserve their primary inclusion assemblages through later amphibolite to lower granulite facies metamorphism.

  20. Modulation of Cenozoic climate by weathering of large igneous provinces on continents drifting through equatorial humid belt

    NASA Astrophysics Data System (ADS)

    Muttoni, G.; Kent, D. V.

    2011-12-01

    total emission of CO2 from modern volcanoes (Gerlach, 2011 Eos). In contrast, large igneous provinces like that 250 Ma Siberian Traps that remained in higher (cooler) latitudes or the 130 Ma Parana located in the tropical arid belt are not major sponges of CO2. And on the supply side, there is presently little subduction of equatorial bulge sediments save for Central America. We conclude that consumption of CO2 by igneous provinces with highly weatherable mafic rocks that drift into the equatorial humid belt is an important and quite possibly the determinant process for modulating levels of pCO2.

  1. Investigation of photoneutron reactions on {sup 192}Os and {sup 191,193}Ir at energies of relevance for the astrophysical p process

    SciTech Connect

    Hasper, J.; Zilges, A.; Galaviz, D.; Mueller, S.; Sauerwein, A.; Savran, D.; Schnorrenberger, L.; Sonnabend, K.

    2009-05-15

    We have investigated the photoneutron reactions on the isotopes {sup 192}Os and {sup 191,193}Ir for astrophysically relevant photon energies just above the neutron separation energy. The experiments were performed using the photoactivation technique at the superconducting Darmstadt linear electron accelerator (S-DALINAC). The measurements extend the existing experimental database on photoneutron reactions in this mass region and serve as an important test for the state-of-the-art statistical model calculations commonly used for the prediction of stellar reaction rates.

  2. Broadband alternating current magnetic susceptibility: Method and application to the characterization of magnetic particles in igneous rocks

    NASA Astrophysics Data System (ADS)

    Kodama, K.

    2012-12-01

    Low-field alternating current magnetic susceptibility (MS) is among the most commonly used magnetic property, not only in rock and mineral magnetism but also in environmental magnetism studies. This study proposes a new rock magnetic method, Frequency Spectrum of MS (FSM), based on the measurement of the real component of MS over a wide range of frequency (100 Hz to 500 kHz) and the measurement of the imaginary component at high frequencies in the order of 10-102 kHz. This study presents the FSM results at room and low temperatures obtained from a variety of igneous rocks with SP to SD grain sizes, including acidic to basic volcanic rocks in Japan and a basalt in Hawaii. The FSMs from the andesite samples at room temperature unexceptionally show small but anomalous increase, as much as 5%, over a specific frequency interval between 10 kHz and 120 kHz. In contrast, FSMs of basalts from Oshima and Hawaii show no such peak, a typical pattern indicating the presence of SP grain ensembles. The anomalous FSM from the andesites suggests a new rock and mineral magnetic behavior indicating either magnetic resonance or magnetic relaxation. Considering the anomalous FSM patterns and their variations at low temperatures, it is suggested that the hypothetical resonance could be relevant to some magnetoelastic phenomenon, in which magnetic energy could be dissipated through a long-range, magnetostructural coupling, most likely, magnetostriction. The fact that the annealed andesite samples showed less developed FSM anomaly strongly supports this hypothesis, because annealing generally lowers the internal stress leading to the reduction of resistance in a forced oscillation system. Analyses of the low temperature results confirm magnetic relaxation phenomena taking place at low temperatures, and consequently support the above interpretation.

  3. The Relevance of the Functional 5-HT1A Receptor Polymorphism for Attention and Working Memory Processes during Mental Rotation of Characters

    ERIC Educational Resources Information Center

    Beste, Christian; Heil, Martin; Domschke, Katharina; Konrad, Carsten

    2010-01-01

    Numerous lines of research indicate that attentional processes, working memory and saccadic processes are highly interrelated. In the current study, we examine the relation between these processes with respect to their cognitive-neurophysiological and neurobiological background by means of event-related potentials (ERPs) in a sample of N = 72…

  4. Minor and trace elements in olivines as probes into early igneous and mantle melting processes

    NASA Astrophysics Data System (ADS)

    Foley, Stephen F.; Prelevic, Dejan; Rehfeldt, Tatjana; Jacob, Dorrit E.

    2013-02-01

    The trace element composition of olivine is a rapidly growing research area that has several applications of great potential. Mantle olivines can be distinguished from volcanic olivines by lower concentrations of Ca (<700 ppm), Ti (<70 ppm), and often Cr. The melting of pyroxenites derived from recycled ocean crust can be recognized in volcanic olivines by correlations of Mn, Al, Sc and Co in addition to Ni. High Ni is characteristic of olivine derived from olivine-free source rocks, but alone it does not distinguish between recycling of ocean crust, continental crust, mantle wedge hybridization, and intra-mantle melt migration. Trace elements help to identify different types of non-peridotitic ultramafic rocks, including those not formed by ocean crust recycling. High Li may be caused by recycling of continental crust, as in Mediterranean post-collisional volcanics or by interaction with carbonatitic melts, and correlation with further elements such as Zn, Na, Ti and Ca will help to identify minerals in the source assemblages, such as phlogopite, spinel, garnet, amphiboles and carbonates, and thus the source of the olivine-free assemblages. Olivines often store the earliest chemical signals of melt loss in peridotites, but later absorb trace elements from passing melts, and are thus excellent monitors of the chemistry of metasomatic agents. Trace elements distinguish between Ti-enrichment by silicate melt metasomatism (high Ti, low Ca) and high-Ca signatures associated with plumes and rift regions that may be due to carbonate-silicate melts. Li may be enriched in olivine in the orogenic mantle, indicating the involvement of melted continental crustal material. Experimental data on element partitioning and diffusion currently partly conflicts with information from natural rocks.

  5. Complex igneous processes and the formation of the primitive lunar crustal rocks

    NASA Technical Reports Server (NTRS)

    Longhi, J.; Boudreau, A. E.

    1979-01-01

    Crystallization of a magma ocean with initial chondritic Ca/Al and REE ratios such as proposed by Taylor and Bence (TB, 1975), is capable of producing the suite of primitive crustal rocks if the magma ocean underwent locally extensive assimilation and mixing in its upper layers as preliminary steps in formation of an anorthositic crust. Lunar anorthosites were the earliest permanent crustal rocks to form the result of multiple cycles of suspension and assimilation of plagioclase in liquids fractionating olivine and pyroxene. There may be two series of Mg-rich cumulate rocks: one which developed as a result of the equilibration of anorthositic crust with the magma ocean; the other which formed in the later stages of the magma ocean during an epoch of magma mixing and ilmenite crystallization. This second series may be related to KREEP genesis. It is noted that crystallization of the magma ocean had two components: a low pressure component which produced a highly fractionated and heterogeneous crust growing downward and a high pressure component which filled in the ocean from the bottom up, mostly with olivine and low-Ca pyroxene.

  6. Mineralogical Variations Among High Albedo E-Type Asteroids: Implications for Asteroid Igneous Processes

    NASA Technical Reports Server (NTRS)

    Gaffey, Michael J.; Kelley, Michael S.

    2004-01-01

    The link between the E-type asteroids and the enstatite achondrites (aubrites) was first proposed for the original E-asteroid, 44 Nysa. The association was based on the high albedos and the featureless spectra shared by the E-asteroids and the aubrites. Among the plausible geologic and meteoritic materials, only enstatite (the magnesium end-member of the pyroxene solid solution series) is sufficiently abundant to comprise asteroid-sized bodies. However, the presence of a weak 0.89 m absorption feature in the spectrum of 44 Nysa indicates that its pyroxene contains a small amount of Fe(2+) but still substantially more than any aubrite present in the meteorite collection. The original E-class was defined based on its high albedo and flat to slightly reddish spectrum. In the absence of albedo data, the E-type was degenerate with the M- and P-types, and together these were designated as X-types. Recently, a taxonomy has been proposed to identify E-types in the absence of albedo data. In this newer classification system three subdivisions of the X-type have been proposed, including Xc, Xe and Xk. Of nine albedo-defined E-types [d], this newer non-albedo based taxonomy produced the following classifications: X-1 asteroid; Xc-2 asteroids; Xe-5 asteroids; and Xk-1 asteroid. Although the Xe subtype includes the largest number of albedo-defined E-types, most of the remaining 24 Xe-types can be excluded based on their low measured IRAS albedos, ranging from 0.116 to 0.329, which are below the lower albedo limit of the E-class (0.34) and substantially below that of the lowest albedo an actual E-type asteroid (0.41). The present discussion will be limited to unambiguous E-type asteroids determined on albedo criteria.

  7. The Importance of Being Relevant

    PubMed Central

    Jaswal, Snehlata

    2012-01-01

    This review aims at an understanding of the binding process by synthesizing the extant perspectives regarding binding. It begins with a consideration of the biological explanations of binding, viz., conjunctive coding, synchrony, and reentrant mechanisms. Thereafter binding is reviewed as a psychological process guided by top-down signals. The stages and types of binding proposed by various researchers are discussed in this section. The next section introduces Working Memory (WM) as the executive directing the top-down signals. After that it is described how WM works by selecting relevant sensory input, followed by a detailed consideration of the debate regarding objects vs. features with the conclusion that relevance is the key factor determining what is processed. The next section considers other factors affecting the selection of relevant input. Then, we shift focus to describe what happens to irrelevant input – whether it is discarded at the outset or is gradually inhibited, and whether inhibition is a perceptual or post-perceptual process. The concluding section describes the process of binding as currently understood on the basis of the literature included in the review. To summarize, it appears that initially the “object” is conceptualized as an instantaneous bundle of all features. However, only relevant features of stimuli are gradually integrated to form a stable representation of the object. Concomitantly, irrelevant features are removed from the object representations. Empirical evidence suggests that the inhibition of irrelevant features occurs over time and is presumably a process within WM. PMID:22969739

  8. Diverse sources for igneous blocks in Franciscan melanges, California Coast Ranges

    SciTech Connect

    MacPherson, G.J. ); Phipps, S.P. ); Grossman, J.N. )

    1990-11-01

    Igneous blocks in Franciscan melanges are of three chemical-petrologic types: (1) tholeiitic basalts of both arc and spreading center origin, with depletions in light relative to heavy rare-earth elements, 3% > TiO{sub 2} > 1%, high Y/Zr and Y/Ti ratios, and relict augites that generally have low Al and Ti and well-defined iron-enrichment trends; (2) basalts of probable seamount origin with marked enrichments in light relative to heavy rare-earth elements, 5% > TiO{sub 2} > 1%, lower Y/Zr and Y/Ti than (1), and Ti-Al-rich augites showing little if any iron-enrichment trends; and (3) hypabyssal intrusives having SiO{sub 2} > 52%, TiO{sub 2} < 1%, flat or only slightly fractionated rare-earth-abundance patterns, and diopsidic augites that are very low in Ti and Al and show no iron-enrichment trends. All of the blocks are metamorphosed; most are undeformed pumpellyite-bearing greenstones, and a few contain sodic amphibole {plus minus} lawsonite {plus minus} sodic pyroxene. The melanges are probably olistostromal in origin, deriving their igneous block detritus both from the downgoing Pacific plate (ocean floor basalts and seamounts) and from the hanging wall of the Franciscan trench (basalts and arc-related silic intrusive rocks). The silicic intrusive rocks and some of the basalts are eroded fragments of the fore-arc crust that ultimately become the Coast Range Ophiolite. These fragments were incorporated into the Franciscan trench fill and subducted. Results suggest that the igneous blocks in ophiolitic melanges provide important information about melange formation and about the tectonics and paleogeography of the regions in which the melanges are found.

  9. Igneous rocks of Arctic Ocean deep sea ridges: new data on petrology, geochemistry and geochronology

    NASA Astrophysics Data System (ADS)

    Petrov, Oleg; Morozov, Andrey; Shokalsky, Sergey; Sobolev, Nikolay; Kashubin, Sergey; Shevchenko, Sergey; Sergeev, Sergey; Belyatsky, Boris; Shatov, Vitaly; Petrov, Eugeny

    2015-04-01

    The aggregate results of studies of igneous rocks, collected from the central part of the Arctic Ocean during scientific marine expeditions «Arctic-2000, 2005, 2007 and 2012» are presented and discussed in the frame of modern understanding of High Polar Arctic tectonic constraint. Petrological, geochemical and isotope-geochronological studies of more than 500 samples have shown that the sedimentary rocks are of dominated population among the rock fragments dredged from deep-sea bottom, and represented by metamorphosed dolomite and quartz sandstone, limestone, sometimes with the Devonian - Permian fauna. Igneous rocks are 10-15% only (Archean and Paleoproterozoic gneissouse granites and gabbro, Neoproterozoic dolerite) and metamorphic rocks (green shales, metabasites, gneisses). Apparently, these rocks are part of the acoustic basement underlying the Late Mesozoic - Cenozoic layered loose sediments. In addition to the dredged fragments of the ancient mafic rocks, some samples were taken as a core during deep-water drilling in the northern and southern slopes of the Mendeleev Ridge and represented by trachybasalts, marking the border of Late-Cenozoic deposit cover and acoustic basement and quite similar in composition to those of Early-Late Cretaceous basalts form northward of the Chukchi Plateau seamounts, Alpha Ridge, Franz Josef Land, De Long islands and other parts of the large igneous province of the High Arctic (HALIP). Video-filming of Mendeleev Ridge escarps proofs the existing of rock outcrops and supports local origin of most of the rock fragments found in the sampling areas. Thus the continental type of the earth's crust of the Central Arctic Ridges basement is based on all obtained results of our study of sea-bottom excavated rock material.

  10. Igneous and Ore-Forming Processes at the Roots of Giant - Ultra-Mafic Pluming System: the Seiland Igneous Comples, Norway

    NASA Astrophysics Data System (ADS)

    Larsen, R. B.; Iljina, M.; Schanke, M.

    2012-12-01

    SIP covers an area of 5500 km2 in N. Norway. 50 % of the volume comprises mafic layered or homogenous plg+px+Fe-Ti±ol gabbros. 25 % of the area comprises ultramafic intrusions, mostly peridotite and subsidiary pyroxenite and hornblendite. 25 % comprises calc-alkaline and alkaline plutons, respectively. Ultramafic plutons intersect gabbros and calc-alkaline plutons. Recent zircon U/Pb geochronology imply that SIP formed at 560-570 Ma, with mafic- and ultramafic rocks being emplaced in <4 Ma (Roberts et al., Geol. Mag, 2007). Geothermobarometry of contact metamorphic mineral assemblages, implies minimum depth of 20-30 kilometres. Accordingly, the Seiland province arguably provides a unique cross section through the deep-seated parts of a huge magmatic plumbing system. Sulphide Cu-Ni-(PGE) deposits are intimately associated with the ultramafic rock suite. One deposit from Stjernøy comprises sulphide dissiminations at the floor of a peridotitic pluton, another deposit occur at the floor of the Reinfjord ultramafic layered complex in the far West of SIP and the third deposit comprises vertical sulphide dykes in the interior of a hornblendite on the Øksfjord peninsula. Currently, only the Reinfjord deposit is studied in detail. The Reinfjord intrusions is layered and develops from olivine clinopyroxenites in the Lower Zone to wherlite in the Middle Zone to wehrlites and dunite in the Upper Zone. Earlier studies suggest parental melts with pyroxenitic compositions whereas the dunites and wherlites formed by fractional crystallization (Bennet et al., Bull. NGU, 405, 1-41). During our fieldwork we observed spectacular examples of cumulus structures, not previously reported, and including modally layered and modally graded dunite/wherlite, cross-bedding, slumping and mush-diapirs. Finally we saw an example of magma-replenishment where an olivine pyroxenitic magma was emplaced in to and mixed with the contemporary olivine/wherlite mushes!. The country rock gabbros were unconsolidated and were partially melted during emplacement of the hot peridotitic melts. Previous studies (Søyland Hansen, 1971, unpub. MSc thesis, NTNU) and our preliminary work document dissiminated Cu-Ni sulphides in a 10-20 metres thick and two km's long deposit at the lower contacts of the Reinfjord intrusion. Several analysis imply 0.15 wt% for both Ni and Cu. The sulphide assemblage iincludes pentlandite, chalcopyrite, pyrrhotite and minor pyrite. Pentlandite is partially bravoitised. Airborne and ground geophysics done as part of our study implied a bowled shaped conducter c. 100 metres below the surface. Exploratory drilling confirmed two layers of 7 and 9 metres, respectively with 0.3-0.4 wt% Ni and minor Cu. The 9 m's zone included 5 m's with 0.6 ppm PGE+Au. Ni is in pentlandite whereas Cu is in chalcopyrite, cubanite or native Cu that apparently exsolved from Chalcopyrite. All sulphide deposits at Reinfjord has only 0.3 to 0.7 wt% S. The source of S is currently unknown, but new sulphur isotope data will be reported at the AGU-meeting.

  11. Relevance of Toxicity Assessment in Wastewater Treatments: Case Study—Four Fenton Processes Applied to the Mineralization of C.I. Acid Red 14

    PubMed Central

    Idel-aouad, Rajaa; Valiente, Manuel; Gutiérrez-Bouzán, Carmen; Vilaseca, Mercè; Yaacoubi, Abdlrani; Tanouti, Boumediene; López-Mesas, Montserrat

    2015-01-01

    Fenton and Fenton-like processes, both in homogeneous and heterogeneous phases, have been applied to an aqueous solution containing the dye AR 14 in order to study the mineralization and toxicity of the solutions generated after color elimination. The mineralization of AR 14 occurred slower than the decolorization. The Microtox analysis of the treated solutions showed low toxicity intrinsic to the chemicals used in the process rather than the degradation products obtained after the treatment of the dye solution. The dye degradation for the Fenton oxidation process was initially faster than for the Fenton-like process but after a short time, the four processes showed similar degradation yields. All processes have shown good results being the heterogeneous process the most convenient since the pH adjustment is not necessary, the catalyst is recovered and reused and the generation of contaminated sludge is avoided. PMID:26167334

  12. Relevance of Toxicity Assessment in Wastewater Treatments: Case Study-Four Fenton Processes Applied to the Mineralization of C.I. Acid Red 14.

    PubMed

    Idel-Aouad, Rajaa; Valiente, Manuel; Gutiérrez-Bouzán, Carmen; Vilaseca, Mercè; Yaacoubi, Abdlrani; Tanouti, Boumediene; López-Mesas, Montserrat

    2015-01-01

    Fenton and Fenton-like processes, both in homogeneous and heterogeneous phases, have been applied to an aqueous solution containing the dye AR 14 in order to study the mineralization and toxicity of the solutions generated after color elimination. The mineralization of AR 14 occurred slower than the decolorization. The Microtox analysis of the treated solutions showed low toxicity intrinsic to the chemicals used in the process rather than the degradation products obtained after the treatment of the dye solution. The dye degradation for the Fenton oxidation process was initially faster than for the Fenton-like process but after a short time, the four processes showed similar degradation yields. All processes have shown good results being the heterogeneous process the most convenient since the pH adjustment is not necessary, the catalyst is recovered and reused and the generation of contaminated sludge is avoided. PMID:26167334

  13. Relevance theory: pragmatics and cognition.

    PubMed

    Wearing, Catherine J

    2015-01-01

    Relevance Theory is a cognitively oriented theory of pragmatics, i.e., a theory of language use. It builds on the seminal work of H.P. Grice(1) to develop a pragmatic theory which is at once philosophically sensitive and empirically plausible (in both psychological and evolutionary terms). This entry reviews the central commitments and chief contributions of Relevance Theory, including its Gricean commitment to the centrality of intention-reading and inference in communication; the cognitively grounded notion of relevance which provides the mechanism for explaining pragmatic interpretation as an intention-driven, inferential process; and several key applications of the theory (lexical pragmatics, metaphor and irony, procedural meaning). Relevance Theory is an important contribution to our understanding of the pragmatics of communication. PMID:26263065

  14. Large igneous provinces generated from the margins of the large low-velocity provinces in the deep mantle

    NASA Astrophysics Data System (ADS)

    Torsvik, Trond H.; Smethurst, Mark A.; Burke, Kevin; Steinberger, Bernhard

    2006-12-01

    There is a clear correlation between downward projected large igneous province (LIP) eruption sites of the past 200 Myr and the margins of the large low-velocity provinces (LLVPs) at the base of the mantle. We established this correlation by using palaeomagnetic as well as fixed and moving hotspot reference frames. Our finding indicates that the majority of the LIPs have been generated by plumes that rose from the D'' zone at the edges of the LLVPs. Most LIP eruption sites project radially downwards to the core-mantle boundary (CMB) within +/-10° of the 1 per cent slow shear wave velocity contour in the SMEAN tomographic model. Steep shear wave velocity gradients have been mapped near the CMB along much of the lengths of the LLVP margins close to that contour which marks a faster/slower boundary (FSB) within the D'' zone. The observation that eruption sites of LIPs as old as 200 Myr can be linked to this prominent present day seismic structure shows that the FSBs of the two LLVPs have occupied their current positions for at least as long and that the process that leads to the generation of deep-seated plumes has been localized on the FSBs at the margins of the African and Pacific LLVPs for the same interval. The persistence of the LLVPs over 200 Myr is consistent with independent evidence that they are compositionally distinct and are not just simply hotter than the material making up the rest of the D'' zone.

  15. Kinetic model of nucleation and growth in silicate melts: Implications for igneous textures and their quantitative description

    NASA Astrophysics Data System (ADS)

    Špillar, Václav; Dolejš, David

    2014-04-01

    We present a new high-resolution numerical model for the simulation of crystallization and texture evolution using arbitrary rates of crystal nucleation and growth. The algorithm models single or multiphase solidification in a three-dimensional domain and 17 simulations using constant, linearly increasing, exponential, and Gaussian functions for the rates of nucleation and growth yield equigranular to seriate textures. Conventional crystal size distributions of all textures are nearly linear to concave-down (previously interpreted as formed by equilibration coarsening), and identical distribution patterns can result from multiple non-unique combinations of nucleation and growth rates. The clustering index is always a non-monotonous function, which initially increases then decreases with increasing crystal fraction. For texture from random homogeneous nucleation the index is substantially lower than previous predictions based on a random sphere distribution line, hence, natural samples interpreted as clustered now have greater degrees of randomness or ordering. The average number of contact neighbors and the average neighbor distance of a crystal depend linearly on crystal size, but one of the two remains insensitive to nucleation and growth kinetics and represents potential indicator of other crystallization processes than random nucleation and crystal growth. Simultaneous comparison of size, spatial and clustering patterns and of their departures from expected values are suggested to allow for separation of effects of crystallization kinetics, melt-mineral mechanical interactions, suspension mixing, or postcrystallization re-equilibration and coarsening on natural igneous rocks.

  16. Lead isotope systematics of some igneous rocks from the Egyptian Shield

    NASA Technical Reports Server (NTRS)

    Gillespie, J. G.; Dixon, T. H.

    1983-01-01

    Lead isotope data on whole-rock samples and two feldspar separates for a variety of Pan-African (late Precambrian) igneous rocks for the Egyptian Shield are presented. It is pointed out that the eastern desert of Egypt is a Late Precambrian shield characterized by the widespread occurrence of granitic plutons. The lead isotope ratios may be used to delineate boundaries between Late Precambrian oceanic and continental environments in northeastern Africa. The samples belong to three groups. These groups are related to a younger plutonic sequence of granites and adamellites, a plutonic group consisting of older tonalites to granodiorites, and the Dokhan volcanic suite.

  17. Pre-Elsonian mafic magmatism in the Nain Igneous Complex, Labrador: the bridges layered intrusion

    USGS Publications Warehouse

    Ashwal, L.D.; Wiebe, R.A.; Wooden, J.L.; Whitehouse, M.J.; Snyder, Diane

    1992-01-01

    Decades of work on the pristine, unmetamorphosed, and well exposed anorthositic, mafic and granitic rocks of the Nain igneous complex, Labrador, have led to the conclusion that all plutonic rocks in that area were emplaced in a short time intercal at about 1300 ?? 10 Ma). We report here new isotopic data for mafic intrusive rocks that appear to have crystallized several hundred Ma earlier than the bulk of the plutonic activity in the Nain complex. The Bridges layered intrusion (BLI) is a small (15-20 km2) lens of layered mafic rocks about 1.5 km thick, surrounded and intruded by anorthositic, leuconoritic and leucotroctolitic plutons in the middle of the coastal section of the Nain igneous complex. BLI shows very well developed magmatic structures, including channel scours, slump structures, and ubiquitous modally graded layering. Most rocks, however, show granular textures indicative of recrystallization, presumably caused by emplacement of younger anorthositic rocks. BLI contains cumulate rocks with slightly more primitive mineral compositions (An60-83, Fo66-71) than those of other mafic intrusions in the Nain igneous complex, including Kiglapait. SmNd isotopic data for 7 BLI whole-rocks ranging in composition between olivine melagabbro and olivine leucogabbro yield an age of 1667 ?? 75 Ma, which we interpret as the time of primary crystallization. The internal isotopic systematics of the BLI have been reset, probably by intrusion of adjacent anorthositic plutons. A SmNd mineral isochron (plag, whole-rock, mafics) for a BLI olivine melagabbro gives an age of 1283 ?? 22 Ma, equivalent within error of a mineral array (plag, whole-rock, opx, cpx) for an adjacent, igneous-textured, leuconorite vein (1266 ?? 152 Ma). The initial Nd ratio for BLI corresponds to ??{lunate}Nd = -3.18 ?? 0.44. Other whole-rock samples, however, some with vein-like alteration (Chlorite, serpentine, amphiboles), show ??{lunate}Nd values as low as -9.1, suggesting variable contamination by

  18. Regional investigations of tectonic and igneous geology, Iran, Pakistan, and Turkey

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The author has identified the following significant results. An extension of the trace of the Chaman-Nushki fault was detected and delineated for 42 km, as was the Ornach-Nal fault for 170 km. Two structural intersections responsible for restricted movements in particular segments of the Chaman-Nushki fault were detected and interpreted. The newest and youngest fault named the Quetta-Mustung-Surab system was delineated for 580 km. The igneous complex of the Lasbela area was interpreted and differentiation was made between ultramafic complex, mafic complex, and basaltic lava flows. One oblong feature was also found which was interpreted as a porphyritic basalt plug.

  19. Intrusive origin of the Sudbury Igneous Complex: Structural and sedimentological evidence

    NASA Technical Reports Server (NTRS)

    Cowan, E. J.; Schwerdtner, W. M.

    1992-01-01

    In recent years, many geoscientists have come to believe that the Sudbury event was exogenic rather than endogenic. Critical to a recent exogenic hypothesis is the impact melt origin of the Sudbury Igneous Complex (SIC). Such origin implies that the SIC was emplaced before deposition of the Whitewater Group, in contrast to origins in which the SIC postdates the lithification of the Onaping Formation. Structural and sedimentological evidence is summarized herein that supports an intrusion of the SIC after lithification of all Whitewater Group strata, and conflicts with the hypothesis advanced by other researchers.

  20. Diverse, Alkali-Rich Igneous and Volcaniclastic Rocks Reflect a Metasomatised Mantle Beneath Gale Crater

    NASA Astrophysics Data System (ADS)

    Schmidt, M. E.; Baker, M. B.; Berger, J. A.; Fisk, M. R.; Gellert, R.; McLennan, S. M.; Newcombe, M. E.; Stolper, E. M.; Thompson, L. M.

    2014-12-01

    Although Curiosity landed in a sedimentary setting, geochemical compositions determined by Alpha Particle X-ray Spectrometer (APXS) and ChemCam suggest that major element concentrations of some rocks were little modified by chemical weathering, and in these cases, the bulk (>70%) of the crystalline components determined by ChemMin are igneous. Gale rocks can therefore largely preserve the composition of their igneous protoliths and provide insight into the crystalline basement exposed in the north crater rim. Four end-member compositions are recognized on the basis of APXS analyses. (1) The diverse, evolved Jake M class (n=12) of inferred igneous origin includes float blocks and cobbles. Jake M rocks are phonotephritic/mugearitic to trachyandesitic and characterized by low MgO contents (3.0-5.7 wt%) and high Al and alkalis, particularly Na2O (up to 7.35 wt%). (2) The Bathurst class of siltstones to coarse sandstones (n=13) occurs as dark-toned float and bedded outcrop and is basaltic to trachybasaltic, ranging to high K2O (up to 3.8 wt%). Alteration of the protolith(s) or during diagenesis may have affected this class. (3) The Darwin class of conglomerates to coarse sandstones (n=10) has high Na and Al, likely reflecting a sodic plagioclase-rich mineralogy, but with higher Fe than Jake M class (13.0-17.1 vs. 6.0-12.5 wt%). (4) The low alkali "normal" Mars basaltic composition is typified by the Portage soils (n=6) and the John Klein class (n=13; includes the Sheepbed mudstone). Some degree of mixing and/or contamination with this low alkali basaltic compositon has affected all APXS analyses. Overall, Gale rocks are strongly enriched in total alkalis (at the same MgO) relative to basaltic shergottites and many have higher K2O than igneous rocks analyzed by Spirit and Opportunity, suggesting that the mantle beneath Gale is alkali-rich (likely as a result of a metasomatic event) and that alkalis are heterogeneously distributed in the planet's interior.

  1. Possible petrogenetic associations among igneous components in North Massif soils: Evidence in 2-4 mm soil particles from 76503

    NASA Technical Reports Server (NTRS)

    Jolliff, Bradley L.; Bishop, Kaylynn M.; Haskin, Larry A.

    1992-01-01

    Studies of Apollo 17 highland igneous rocks and clasts in breccias from the North and South Massifs have described magnesian troctolite, norite, anorthositic gabbro, dunite, spinel cataclasites, and granulitic lithologies that may have noritic anothosite or anorthositic norite/gabbro as igneous precursors, and have speculated on possible petrogenetic relationships among these rock types. Mineral compositions and relative proportions of plagioclase and plagioclase-olivine particles in samples 76503 indicate that the precursor lithology of those particles were troctolitic anorthosite, not troctolite. Mineral and chemical compositions of more pyroxene-rich, magnesian breccias and granulites in 76503 indicate that their precursor lithology was anorthositic norite/gabbro. The combination of mineral compositions and whole-rock trace-element compositional trends supports a genetic relationship among these two groups as would result from differentiation of a single pluton. Although highland igneous lithologies in Apollo 17 materials have been described previously, the proportions of different igneous lithologies present in the massifs, their frequency of association, and how they are related are not well known. We consider the proportions of, and associations among, the igneous lithologies found in a North Massif soil, which may represent those of the North Massif or a major part of it.

  2. Gaining control: changing relations between executive control and processing speed and their relevance for mathematics achievement over course of the preschool period

    PubMed Central

    Clark, Caron A. C.; Nelson, Jennifer Mize; Garza, John; Sheffield, Tiffany D.; Wiebe, Sandra A.; Espy, Kimberly Andrews

    2014-01-01

    Early executive control (EC) predicts a range of academic outcomes and shows particularly strong associations with children's mathematics achievement. Nonetheless, a major challenge for EC research lies in distinguishing EC from related cognitive constructs that also are linked to achievement outcomes. Developmental cascade models suggest that children's information processing speed is a driving mechanism in cognitive development that supports gains in working memory, inhibitory control and associated cognitive abilities. Accordingly, individual differences in early executive task performance and their relation to mathematics may reflect, at least in part, underlying variation in children's processing speed. The aims of this study were to: (1) examine the degree of overlap between EC and processing speed at different preschool age points; and (2) determine whether EC uniquely predicts children's mathematics achievement after accounting for individual differences in processing speed. As part of a longitudinal, cohort-sequential study, 388 children (50% boys; 44% from low income households) completed the same battery of EC tasks at ages 3, 3.75, 4.5, and 5.25 years. Several of the tasks incorporated baseline speeded naming conditions with minimal EC demands. Multidimensional latent models were used to isolate the variance in executive task performance that did not overlap with baseline processing speed, covarying for child language proficiency. Models for separate age points showed that, while EC did not form a coherent latent factor independent of processing speed at age 3 years, it did emerge as a distinct factor by age 5.25. Although EC at age 3 showed no distinct relation with mathematics achievement independent of processing speed, EC at ages 3.75, 4.5, and 5.25 showed independent, prospective links with mathematics achievement. Findings suggest that EC and processing speed are tightly intertwined in early childhood. As EC becomes progressively decoupled from

  3. Porosity and surface area evolution during weathering of two igneous rocks

    SciTech Connect

    Navarre-Sitchler, Alexis; Cole, David; Rother, Gernot; Jin, Lixin; Buss, Heather; Brantley, S. L.

    2013-01-01

    During weathering, rocks release nutrients and storewater vital for growth ofmicrobial and plant life. Thus, the growth of porosity as weathering advances into bedrock is a life-sustaining process for terrestrial ecosystems. Here, we use small-angle and ultra small-angle neutron scattering to show how porosity develops during initial weathering under tropical conditions of two igneous rock compositions, basaltic andesite and quartz diorite. The quartz diorite weathers spheroidally while the basaltic andesite does not. The weathering advance rates of the two systems also differ, perhaps due to this difference in mechanism, from 0.24 to 100 mm kyr1, respectively. The scattering data document how surfaces inside the feldspar-dominated rocks change as weathering advances into the protolith. In the unaltered rocks, neutrons scatter fromtwo types of featureswhose dimensions vary from6 nmto 40 lm: pores and bumps on pore grain surfaces. These features result in scattering data for both unaltered rocks that document multi-fractal behavior: scattering is best described by amass fractal dimension (Dm) and a surface fractal dimension (Ds) for features of length scales greater than and less than 1 lm, respectively. In the basaltic andesite, Dm is approximately 2.9 and Ds is approximately 2.7. The mechanism of solute transport during weathering of this rock is diffusion. Porosity and surface area increase from 1.5%to 8.5%and 3 to 23 m2 g1 respectively in a relatively consistent trend across themm-thick plagioclase reaction front. Across this front, both fractal dimensions decrease, consistentwith development of amoremonodisperse pore networkwith smoother pore surfaces. Both changes are consistent largely with increasing connectivity of pores without significant surface roughening, as expected for transport-limited weathering. In contrast, porosity and surface area increase from 1.3% to 9.5% and 1.5 to 13 m2 g1 respectively across a many cm-thick reaction front in the

  4. Mid-Paleoproterozoic (Jatulian) large igneous province of the Phanerozoic type, eastern Fennoscandian Shield

    NASA Astrophysics Data System (ADS)

    Bogina, M. M.; Sharkov, E. V.; Zlobin, V. L.; Chistyakov, A. V.

    2013-12-01

    The Mid-Paleoprotrozoic Jatulian large igneous province (LIP) are located at the eastern Fennoscandian Shield. It is formed by lava plateaus in riftogenic structures, dyke swarms and different intrusions, and developed in range 2.35-2.06 Ga. All volcanics were undergone by greenschist alterations with practically complete replacement of original minerals by albite, actinolite, epidote, and chlorite, however, their primary structures and textures are often survived. Pillow-lavas are rare, which evidence about predominance of subaerial eruptions and it is in agreement with continental conditions of their formation. Jatulian complexes has studied about a hundred years, however, their geochemistry is known poor. So, we present here the new data for the better understanding this province. Jatulian rocks in Karelia are represented by basalts and andesibasalts of normal alkalinity with subordinate alkali basalts. The rocks are characterized by narrow variations of SiO2 (usually up to 53 wt.%); TiO2 content is vary from 0.72 to 3.06 wt.%, and mg# from 30 to 65. Spectrums REE of the basalts are characterized by low to moderate fractionation: (La/YbN= 1.28-5.27) under low fractionation of LREE (La/SmN=0.9-2.15) and HREE (Gd/YbN=1.19-2.55) and slight Eu-anomaly right up to it absence. At that group of high-Ti rocks is characterized by higher REE content. On multicomponet diagrams Jatulian rocks have moderate negative Nb-anomaly, which decreases up to section and sometimes becomes positive under weakly positive or absent Ti-anomaly. Jatulian volcanics on Kola Craton are located in Pechenga structure (Kuetsjarvi and Kolosiok Formation) and in Imandra-Varzuga structure (Umba Fm). Rocks of Kuetsjarvi Fm are characterized by very wide diversity, vary on SiO2 content from alkali basalts via trachyandesites, trachydacites to rhyolites. Such series of rocks very rare in the early Precambrian, which sharply distinguish them from the most Precambrian volcanics on the shield. Majority

  5. 3D Seismic Studies of Igneous Intrusions, Taranaki Basin, off-shore west New Zealand

    NASA Astrophysics Data System (ADS)

    Harbor, R. L.; Chrisitiansen, E. H.; Keach, R. W.

    2008-12-01

    Several off-shore volcano-plutonic complexes are imaged in a detailed 3D seismic survey acquired by Pogo New Zealand/Plains Exploration. The new data provide insight into the sizes, shapes, and wall rock deformation associated with the emplacement of plutons. The seismic survey, conducted in 2005, covers 1700 km2 and was processed with modern techniques used in hydrocarbon exploration. The images and structures have to be interpreted with care because of distortions caused by "velocity pull ups" created by the large seismic wave velocity contrast between sediment and igneous rock. The magmatic rocks may be part of the Mohakatino Volcanic Centre (15 to 1.5 Ma) that intrudes and partially fills the Taranaki graben, which began to form in the Cretaceous. Imaged plutons range from less than 1 to as much as 12 km across. The intrusions are steep-sided and do not resemble sills, but their bases are poorly resolved. The top of the largest complex is sharply delineated and marked by multiple apophyses as much as 2 km across and hundreds of meters high. Deformation along the sides of the intrusion is dominated by of a faulted rim anticline, with apparent dips of 45° or higher. Dips decrease rapidly away from the intrusion but doming extends several hundred meters from the margins. A series of high-angle faults fan out from the margin of the pluton and cut the folded strata along the margin. These faults terminate against the margins of the intrusion, extend as much as 1 pluton diameter away from the margin, and then merge with "regional" faults that are part of the Taranaki graben. Offset along these radiating faults is on the order of a few hundred meters. Strata on the top of the complex are thinned but are deformed into a faulted dome with an amplitude of about 1 km. Steep, dip-slip faults form a semi-radial pattern in the roof rocks but are strongly controlled by the regional stress field as many of the faults are sub-parallel to those that form the graben. The longest

  6. Origin of the Mackenzie large igneous province and sourcing of flood basalts from layered intrusions

    NASA Astrophysics Data System (ADS)

    Day, J. M.; Pearson, D.

    2013-12-01

    The 1.27 Ga Coppermine continental flood basalt (CFB) in northern Canada represents the extrusive manifestation of the Mackenzie large igneous province (LIP) that includes the Mackenzie dyke swarm and the Muskox layered intrusion. New Re-Os isotope and highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os) abundance data are reported together with whole-rock major- and trace-element abundances and Nd isotopes to examine the behaviour of the HSE during magmatic differentiation and to place constraints on the extent of crustal interaction with mantle-derived melts. Mineral-chemical data are also reported for an unusual andesite glass flow (4.9 wt.% MgO) found in proximity to newly recognised picrites (>20 wt.% MgO) in the lowermost stratigraphy of the Coppermine CFB. Compositions of mineral phases in the andesite are similar to equivalent phases found in Muskox Intrusion chromitites and the melt composition is identical to Muskox chromite melt inclusions. Elevated HSE contents (e.g., 3.8 ppb Os) and the mantle-like initial Os isotope composition of this andesitic glass contrast strongly with oxygen isotope and lithophile element evidence for extensive crustal contamination. These signatures implicate an origin for the glass as a magma mingling product formed within the Muskox Intrusion during chromitite genesis. The combination of crust and mantle signatures define roles for both these reservoirs in chromitite genesis, but the HSE appear to be dominantly mantle-sourced. Combined with Nd isotope data that places the feeder for lower Coppermine CFB picrites and basalts within the Muskox Intrusion, this provides the strongest evidence yet for direct processing of some CFB within upper-crustal magma chambers. Modeling of absolute and relative HSE abundances in CFB reveal that HSE concentrations decrease with increasing fractionation for melts with <8×1 wt.% MgO in the Coppermine CFB, with picrites (>13.5wt.% MgO) from CFB having higher Os abundances than ocean island

  7. Electrochemical effects of magmatic crystallisation: cyclic units of the Bushveld Igneous Complex

    NASA Astrophysics Data System (ADS)

    Veksler, Ilya V.; Reid, David L.; Dulski, Peter; Keiding, Jakob K.; Trumbull, Robert B.

    2013-04-01

    The Upper Critical Zone (UCZ) of the Bushveld Igneous Complex displays spectacular layering in the form of cyclic units comprising a basal chromitite layer overlain by a sequence of silicate cumulates in the order, from the bottom to the top, pyroxentite-norite-anorthosite. Electron microprobe and laser ablation ICP-MS analyses of chromite and silicate cumulate minerals in the cyclic units between the UG2 chromitite and the Merensky reef revealed variations in major and trace element compositions that are difficult to reconcile with existing models of cumulate mineral-melt evolution. The anomalies in mineral chemistry are best developed at sharp contacts of chromitites with adjacent anorthosite and pyroxenitic cumulates. At the contacts, major element characteristics of chromite composition change abruptly from high and stable Mg/(Mg+Fe2+) and Fe2+/Fe3+ typical for cumulus chromitites to variable and generally low values in chromite crystals disseminated in silicate cumulates. Chromites from different types of cumulates also differ in Sc, V, Ni and Zn contents. The abrupt changes in chromite composition mark the contacts regardless of the thickness of the chromitite layer and estimated mass proportions of chromite to intercumulus liquid. Chemical variations, which defy a simple explanation, are also observed in plagioclase. In addition to previously revealed inconsistency between chemical trends of cumulus plagioclase and orthopyroxene in the UCZ cyclic units our study demonstrates that intercumulus, poikilitic plagioclase cementing chromitite layers has anomalously low Li, K, Rb concentrations and K/La values. Summarising previous studies and the new trace element data we propose a model of post-cumulus re-crystallisation leading to consolidation of a modally layered crystal-liquid mush into a sequence of nearly monomineral layers of chromitites, pyroxenites and anorthosites, which defines the cyclic units. The crucial element of the model is the establishment of

  8. Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction

    PubMed Central

    Zhao, Zi-Fu; Dai, Li-Qun; Zheng, Yong-Fei

    2013-01-01

    Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and its adjacent continental margin in the North China Block. These rocks exhibit the geochemical inheritance of whole-rock trace elements and Sr-Nd-Pb isotopes as well as zircon U-Pb ages and Hf-O isotopes from felsic melts derived from the subducted continental crust. Reaction of such melts with the overlying wedge peridotite would transfer the crustal signatures to the mantle sources for postcollisional mafic magmatism. Therefore, postcollisonal mafic igneous rocks above continental subduction zones are an analog to arc volcanics above oceanic subduction zones, providing an additional laboratory for the study of crust-mantle interaction at convergent plate margins. PMID:24301173

  9. Late Triassic, arc-related, potassic igneous rocks in the North American Cordillera

    NASA Astrophysics Data System (ADS)

    Mortimer, N.

    1986-12-01

    Igneous rocks of Late Triassic age are widespread in the Cordillera of western North America and, except in Wrangellia, consist of subduction-related plutonic and volcanic suites. Many of these, including those in the Stikinia, Quesnellia, Rattlesnake Creek, and Jackson terrenes and in southern California, are clinopyroxene rich and belong to high-potassium and shoshonitic rock series, features that are generally absent from older and younger igneous rocks in the same terranes. The Late Triassic subduction-related rocks are exposed in two discontinuous belts that lie east and west of the Cache Creek terrane in Canada and correlative melange terranes farther south. Stratigraphic and structural data suggest that these belts were spatially separate magmatic arcs in Late Triassic time. Tectonic implications of this analysis include an explanation of Middle Jurassic Cordilleran deformation as the result of collision of the western with the eastern belt, absence of Late Triassic links between Stikinia and Quesnellia, disassociation of Stikinia with terranes in northwestern Nevada, and tentative correlation of the Wallowa (Seven Devils) terrane with Stikinia rather than Wrangellia. *Present address: New Zealand Geological Survey, Department of Scientific and Industrial Research, Private Bag, Dunedin, New Zealand

  10. Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction.

    PubMed

    Zhao, Zi-Fu; Dai, Li-Qun; Zheng, Yong-Fei

    2013-01-01

    Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and its adjacent continental margin in the North China Block. These rocks exhibit the geochemical inheritance of whole-rock trace elements and Sr-Nd-Pb isotopes as well as zircon U-Pb ages and Hf-O isotopes from felsic melts derived from the subducted continental crust. Reaction of such melts with the overlying wedge peridotite would transfer the crustal signatures to the mantle sources for postcollisional mafic magmatism. Therefore, postcollisonal mafic igneous rocks above continental subduction zones are an analog to arc volcanics above oceanic subduction zones, providing an additional laboratory for the study of crust-mantle interaction at convergent plate margins. PMID:24301173

  11. Magnetic petrofabric of igneous rocks: Lessons from pyroclastic density current deposits and obsidians

    NASA Astrophysics Data System (ADS)

    Cañón-Tapia, E.; Mendoza-Borunda, R.

    2014-12-01

    Measurement of the anisotropy of magnetic susceptibility (AMS) of igneous rocks can provide clues concerning their mechanism of formation and in particular are very helpful as flow direction indicators. Unlike other igneous rocks, however, pyroclastic density current deposits (PDCDs) present a challenge in the interpretation of AMS measurements due to the complexity of their mechanism of emplacement. In this paper we review the most common assumptions made in the interpretation of the AMS of PDCD, taking advantage of key lessons obtained from obsidians. Despite the complexities on the mechanism of formation of PDCDs, it is shown that a key element for the fruitful interpretation of AMS is to give proper attention to the various components likely to be involved in controlling their general petrofabric. The anisotropies of ferromagnetic crystals (whether as free phases or embedded within clasts or shards), and those of paramagnetic minerals (mainly ferrosilicates) need to be taken into consideration when interpreting the AMS measurements of PDCDs. Variations of the deposition regime both as a function of position and of time also need to be considered on the interpretations. Nevertheless, if a suitable sampling strategy is adopted, the potential of the AMS method as a petrofabric indicator is maximized.

  12. Paleogene time scale miscalibration: Evidence from the dating of the North Atlantic igneous province

    NASA Astrophysics Data System (ADS)

    Jolley, David W.; Clarke, Benjamin; Kelley, Simon

    2002-01-01

    Igneous activity in the North Atlantic igneous province began with the arrival of the proto-Iceland plume beneath the lithosphere in early Cenozoic time. Sediments between and equivalent to the oldest lavas contain an influx of a diagnostic pollen flora, an influx of the dinocyst Apectodinium, a benthic foraminiferal extinction, nannofossil zone NP9, and a carbon isotope excursion associated with the late Paleocene thermal maximum (LPTM). Lavas immediately overlying the LPTM strata (54.98 Ma on the current time scale), yield U-Pb and Ar-Ar isotopic dates between 57.5 and 60.54 Ma, highlighting a dating discrepancy of up to 5 m.y. Recognition of this disparity, as well as our biostratigraphical correlation, places the LPTM within the early phase of widespread northeast Atlantic margin basaltic volcanism. A later volcanic phase, equivalent to the seaward-dipping reflector series, terminates at 54 Ma. The onset of 60 Ma basaltic volcanism can be linked to ocean water mass perturbations, and the release of ocean-floor methane hydrates thought responsible for the LPTM.

  13. Raman spectroscopic characterization of a highly weathered basalt: Igneous mineralogy, alteration products, and a microorganism

    NASA Astrophysics Data System (ADS)

    Wang, Alian; Jolliff, Bradley L.; Haskin, Larry A.

    On-surface identification of minerals on Mars is likely to depend mainly on observations of rocks and soils as found, without access to fresh surfaces or other sample preparation. Both the original mineralogy of rocks and their alteration mineralogy will be important. To determine the capability of Raman spectroscopy to provide good mineralogical characterization of an altered igneous rock such as might be encountered on Mars, we have analyzed the heavily weathered, exterior surface of a cobble of Keweenawan basalt and compared the results with those from a roughly cut, unpolished interior surface, using a Raman point-counting method. Despite ubiquitous hematite, a strong Raman scatterer, and despite considerable alteration, original igneous plagioclase and pyroxene were identified and their approximate proportions determined from point-counting traverses on the original surface of the rock. Saponite, an alteration product, was easily identified on the freshly cut surface but could only occasionally be identified on the weathered surface, where saponite-rich areas were highly photoluminescent. Amygdular fill gave strong spectra of calcite and thomsonite (a zeolite). Tiny, sparse crustose lichen gave clear spectra of their waxy organic coating. On the basis of the surface Raman spectra alone, the rock could be identified as a mafic rock, probably basaltic, that was hydrothermally altered in an oxidizing environment at a temperature between ~250 and ~350°C.

  14. Intraterrestrial life in igneous ocean crust: advances, technologies, and the future (Invited)

    NASA Astrophysics Data System (ADS)

    Edwards, K. J.; Wheat, C. G.

    2010-12-01

    The “next frontier” of scientific investigation in the deep sub-seafloor microbial biosphere lies in a realm that has been a completely unexplored until just the past decade: the igneous oceanic crust. Problems that have hampered exploration of the “hard rock” marine deep biosphere have revolved around sample access (hard rock drilling is technologically complex), contamination (a major hurdle), momentum (why take on this challenge when the relatively “easier” marine muds also have been a frontier) and suspicion that microbes in more readily accessed using (simpler) non-drilling technologies - like vents - are truly are endemic of subsurface clades/activities. Since the late 1990’s, however, technologies and resultant studies on microbes in the igneous ocean crust deep biosphere have risen sharply, and offer a new and distinct view on this biome. Moreover, microbiologists are now taking leading roles in technological developments that are critically required to address this biosphere - interfacing and collaborating closely with engineers, genomic biologists, geologists, seismologists, and geochemists to accomplish logistically complex and long-term studies that bring observatory research to this deep realm. The future of this field for the least decade is rich - opportunities abound for microbiologists to play new roles in how we study microbiology in the deep subsurface in an oceanographic and Earth system science perspective.

  15. Geochemical Database for Igneous Rocks of the Ancestral Cascades Arc - Southern Segment, California and Nevada

    USGS Publications Warehouse

    du Bray, Edward A.; John, David A.; Putirka, Keith; Cousens, Brian L.

    2009-01-01

    Volcanic rocks that form the southern segment of the Cascades magmatic arc are an important manifestation of Cenozoic subduction and associated magmatism in western North America. Until recently, these rocks had been little studied and no systematic compilation of existing composition data had been assembled. This report is a compilation of all available chemical data for igneous rocks that constitute the southern segment of the ancestral Cascades magmatic arc and complement a previously completed companion compilation that pertains to rocks that constitute the northern segment of the arc. Data for more than 2,000 samples from a diversity of sources were identified and incorporated in the database. The association between these igneous rocks and spatially and temporally associated mineral deposits is well established and suggests a probable genetic relationship. The ultimate goal of the related research is an evaluation of the time-space-compositional evolution of magmatism associated with the southern Cascades arc segment and identification of genetic associations between magmatism and mineral deposits in this region.

  16. K/Na ratio of Cenozoic igneous rocks of the western United States

    USGS Publications Warehouse

    Moore, J.G.

    1962-01-01

    The potassium and sodium content of chemically analysed Cenozoic igneous rocks from about 150 areas of the western United States has been examined. For each area a plot of the molecular proportion K2O (K2O + Na2O) [Niggli's k-value] is shown, and the projected k-value determined at 50 and 60 weight per cent SiO2. The k-values are plotted and contoured on maps of the western United States. These maps show that potassium is least abundant relative to total alkali (when rocks of the same SiO2 content are compared) in a zone along the Pacific Coast, becomes more abundant eastward, and is highest in the Colorado Plateau and Northern Rocky Mountains. These k-value variations can be related to regional variations in the abundance of certain trace elements and of different types of older granitic rocks, and to Bouguer gravity maps. This correspondence indicates that the alkali ratio of Cenozoic igneous rocks is closely related to the character of the crust where the rocks are formed. ?? 1962.

  17. Perceptions of document relevance

    PubMed Central

    Bruza, Peter; Chang, Vivien

    2014-01-01

    This article presents a study of how humans perceive and judge the relevance of documents. Humans are adept at making reasonably robust and quick decisions about what information is relevant to them, despite the ever increasing complexity and volume of their surrounding information environment. The literature on document relevance has identified various dimensions of relevance (e.g., topicality, novelty, etc.), however little is understood about how these dimensions may interact. We performed a crowdsourced study of how human subjects judge two relevance dimensions in relation to document snippets retrieved from an internet search engine. The order of the judgment was controlled. For those judgments exhibiting an order effect, a q–test was performed to determine whether the order effects can be explained by a quantum decision model based on incompatible decision perspectives. Some evidence of incompatibility was found which suggests incompatible decision perspectives is appropriate for explaining interacting dimensions of relevance in such instances. PMID:25071622

  18. The role of physiological elements in the future therapies of rheumatoid arthritis. II. The relevance of energy redistribution in the process of chronic inflammation.

    PubMed

    Gajewski, Michał; Rzodkiewicz, Przemysław; Wojtecka-Łukasik, Elżbieta

    2015-01-01

    The reasons for development of chronic inflammation are complex and not fully understood. One of the factors affecting the prolongation of inflammation is changes in cell metabolism, occurring at the center of the inflammatory process. In chronic inflammation there is an imbalance between the processes of storage and consumption of energy reserves. Hypoxia that is a consequence of edema results in transition of white blood cells to anaerobic metabolism. Neutrophils, lymphocytes and macrophages produce active oxygen metabolites which on one hand facilitate the elimination of pathogens, and on the other hand, can cause damage to healthy cells located in the inflamed tissue. In this paper, we discuss the importance of disturbed redistribution of energy as one of the main reasons for transformation of the acute inflammatory process into the chronic one. PMID:27407224

  19. The role of physiological elements in the future therapies of rheumatoid arthritis. II. The relevance of energy redistribution in the process of chronic inflammation*

    PubMed Central

    Rzodkiewicz, Przemysław; Wojtecka-Łukasik, Elżbieta

    2015-01-01

    The reasons for development of chronic inflammation are complex and not fully understood. One of the factors affecting the prolongation of inflammation is changes in cell metabolism, occurring at the center of the inflammatory process. In chronic inflammation there is an imbalance between the processes of storage and consumption of energy reserves. Hypoxia that is a consequence of edema results in transition of white blood cells to anaerobic metabolism. Neutrophils, lymphocytes and macrophages produce active oxygen metabolites which on one hand facilitate the elimination of pathogens, and on the other hand, can cause damage to healthy cells located in the inflamed tissue. In this paper, we discuss the importance of disturbed redistribution of energy as one of the main reasons for transformation of the acute inflammatory process into the chronic one. PMID:27407224

  20. β decay of nuclei around 90Se: Search for signatures of a N=56 subshell closure relevant to the r process

    NASA Astrophysics Data System (ADS)

    Quinn, M.; Aprahamian, A.; Pereira, J.; Surman, R.; Arndt, O.; Baumann, T.; Becerril, A.; Elliot, T.; Estrade, A.; Galaviz, D.; Ginter, T.; Hausmann, M.; Hennrich, S.; Kessler, R.; Kratz, K.-L.; Lorusso, G.; Mantica, P. F.; Matos, M.; Montes, F.; Pfeiffer, B.; Portillo, M.; Schatz, H.; Schertz, F.; Schnorrenberger, L.; Smith, E.; Stolz, A.; Walters, W. B.; Wöhr, A.

    2012-03-01

    Background: Nuclear structure plays a significant role on the rapid neutron capture process (r process) since shapes evolve with the emergence of shells and subshells. There was some indication in neighboring nuclei that we might find examples of a new N=56 subshell, which may give rise to a doubly magic 3490Se56 nucleus.Purpose: β-decay half-lives of nuclei around 90Se have been measured to determine if this nucleus has in fact a doubly magic character.Method: The fragmentation of a 136Xe beam at the National Superconducting Cyclotron Laboratory at Michigan State University was used to create a cocktail of nuclei in the A=90 region.Results: We have measured the half-lives of 22 nuclei near the r-process path in the A=90 region. The half-lives of 88As and 90Se have been measured for the first time. The values were compared with theoretical predictions in the search for nuclear-deformation signatures of a N=56 subshell, and its possible role in the emergence of a potential doubly magic 90Se. The impact of such hypothesis on the synthesis of heavy nuclei, particularly in the production of Sr, Y, and Zr elements was investigated with a weak r-process network.Conclusions: The new half-lives agree with results obtained from a standard global QRPA model used in r-process calculations, indicating that 90Se has a quadrupole shape incompatible with a closed N=56 subshell in this region. The impact of the measured 90Se half-life in comparison with a former theoretical predication associated with a spherical half-life on the weak r process is shown to be strong.

  1. Simulating the Scintillating Cosmic Ray Eliminating ENsemble (SuNSCREEN) for reducing cosmic background in experiments relevant for the p-process

    NASA Astrophysics Data System (ADS)

    Klopfer, Emily; Spyrou, Artemis; Simon, Anna; Quinn, Stephen; Dombos, Alexander; Deyoung, Paul; Brett, Jaclyn

    2013-10-01

    Naturally occurring, proton rich isotopes that cannot be produced in the s- or r- neutron capture processes are called p-nuclei. Their nucleosynthesis proceeds by the p-process; a process that is still not well understood. This process may be studied by measuring (p, γ) and (α, γ) reactions using the Summing NaI(TI) detector (SuN) created at NSCL. The SuN detector uses a summing technique where all the gamma rays emitted from a single compound nucleus are summed into one peak that can then be analyzed. One problem with this method is the background created by cosmic rays at high-energy regions of the gamma spectrum. To counteract this drawback a veto detector, SuNSCREEN (Scintillating Cosmic Ray Eliminating Ensemble), is being developed to reduce this cosmic ray background. The present work was centered on producing a simulation of SuNSCREEN and cosmic rays utilizing GEANT4 software and the comparison of these simulations to experimental data.

  2. A Study of Secondary Students' Decision-Making Processes with Respect to Information Use, Particularly Students' Judgements of Relevance and Reliability

    ERIC Educational Resources Information Center

    Watson, Curtis L.

    2010-01-01

    This report details an ongoing investigation of the decision-making processes of a group of secondary school students in south-eastern Australia undertaking information search tasks. The study is situated in the field of information seeking and use, and, more broadly, in decision making. Research questions focus on students' decisions about the…

  3. Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Hirsikko, A.; Vakkari, V.; Tiitta, P.; Manninen, H. E.; Gagné, S.; Laakso, H.; Kulmala, M.; Mirme, A.; Mirme, S.; Mabaso, D.; Beukes, J. P.; Laakso, L.

    2012-05-01

    South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC). The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM) were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO2, NOx, CO) and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM10 and O3 concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during nucleation events were similar to results previously published for a semi

  4. Rigor, Relevance and Relationships

    ERIC Educational Resources Information Center

    McNulty, Raymond J.; Quaglia, Russell J.

    2007-01-01

    Rigor, relevance, and relationships are three elements that provide the hallmark for education today. These three elements are integrally connected; if one is missing in a teacher's teaching practices, he or she is not doing his or her best to prepare students for success in school and in life. To ensure the inclusion of both rigor and relevance,…

  5. Making Science Relevant

    ERIC Educational Resources Information Center

    Eick, Charles; Deutsch, Bill; Fuller, Jennifer; Scott, Fletcher

    2008-01-01

    Science teachers are always looking for ways to demonstrate the relevance of science to students. By connecting science learning to important societal issues, teachers can motivate students to both enjoy and engage in relevant science (Bennet, Lubben, and Hogarth 2007). To develop that connection, teachers can help students take an active role in…

  6. Culturally Relevant Pedagogy

    ERIC Educational Resources Information Center

    Irvine, Jacqueline Jordan

    2010-01-01

    Many teachers have only a cursory understanding of culturally relevant pedagogy, and their efforts to bridge the cultural gap often fall short. Culturally relevant pedagogy is a term that describes effective teaching in culturally diverse classrooms. It can be a daunting idea to understand and implement. Yet people tend to appreciate culturally…

  7. Characterize Eruptive Processes at Yucca Mountain, Nevada

    SciTech Connect

    G. Valentine

    2001-12-20

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain shapes.

  8. Neural processing of fearful and happy facial expressions during emotion-relevant and emotion-irrelevant tasks: A fixation-to-feature approach.

    PubMed

    Neath-Tavares, Karly N; Itier, Roxane J

    2016-09-01

    Research suggests an important role of the eyes and mouth for discriminating facial expressions of emotion. A gaze-contingent procedure was used to test the impact of fixation to facial features on the neural response to fearful, happy and neutral facial expressions in an emotion discrimination (Exp.1) and an oddball detection (Exp.2) task. The N170 was the only eye-sensitive ERP component, and this sensitivity did not vary across facial expressions. In both tasks, compared to neutral faces, responses to happy expressions were seen as early as 100-120ms occipitally, while responses to fearful expressions started around 150ms, on or after the N170, at both occipital and lateral-posterior sites. Analyses of scalp topographies revealed different distributions of these two emotion effects across most of the epoch. Emotion processing interacted with fixation location at different times between tasks. Results suggest a role of both the eyes and mouth in the neural processing of fearful expressions and of the mouth in the processing of happy expressions, before 350ms. PMID:27430934

  9. Potential temperature, upwelling rate and eclogite in the formation of the North Atlantic large igneous province

    NASA Astrophysics Data System (ADS)

    Brown, E. L.; Lesher, C. E.

    2010-12-01

    The volumes and compositions of basalts generated by adiabatic decompression melting of the Earth’s mantle depend on mantle potential temperature (T_P), upwelling rate and the fertility of the mantle source. The relative importance of these factors in generating the high productivity magmatism of the Paleogene - Recent North Atlantic large igneous province (NAIP) remains controversial. Each has been proposed as a primary factor in the region. To assess the significance of these mechanisms in NAIP magmatism, we apply our forward melting model, REEBOX PRO, which simulates the melting of a heterogeneous source comprised of peridotite and eclogite lithologies. The model accounts for the thermodynamics of adiabatic decompression melting of a heterogeneous source using constraints from laboratory melting experiments. Input values of T_P and eclogite abundance are used to calculate the buoyancy of the mantle source and maximum upwelling rates. Source buoyancy constrains the maximum amount of eclogite in the mantle source that can ascend beneath the rift axis. All melts generated within the melting regime are pooled to form magmatic crust according to the residual column method. Using the model, variations in magmatic crustal thickness (from geophysics) as a function of eclogite content (from geochemistry) can be related to T_P and upwelling rate. Models with no thermal anomaly, that call on either enhanced upwelling rates due to plate separation (edge - driven convection) or the melting of abundant (> 30%) eclogite at “ambient” T_P (1325 °C), cannot generate the observed igneous crustal thicknesses around the province. Rather, elevated mantle T_P (minimum thermal anomaly ~ 85 - 195 °C) and associated buoyancy - driven upwelling are needed to explain the volume of igneous crust in the province. Involvement of eclogite, while necessary to explain the compositions of many NAIP lavas, does not significantly enhance melt production. These factors, coupled with the long

  10. Building the EarthChem System for Advanced Data Management in Igneous Geochemistry

    NASA Astrophysics Data System (ADS)

    Lehnert, K.; Walker, J. D.; Carlson, R. W.; Hofmann, A. W.; Sarbas, B.

    2004-12-01

    Several mature databases of geochemical analyses for igneous rocks are now available over the Internet. The existence of these databases has revolutionized access to data for researchers and students allowing them to extract data sets customized to their specific problem from global data compilations with their desktop computer within a few minutes. Three of the database efforts - PetDB, GEOROC, and NAVDAT - have initiated a collaborative effort called EarthChem to create better and more advanced and integrated data management for igneous geochemistry. The EarthChem web site (http://www.earthchem.org/) serves as a portal to the three databases and information related to EarthChem activities. EarthChem participants agreed to establish a dialog to minimize duplication of effort and share useful tools and approaches. To initiate this dialog, a workshop was run by EarthChem in October, 2003 to discuss cyberinfrastructure needs in igneous geochemistry (workshop report available at the EarthChem site). EarthChem ran an information booth with database and visualization demonstrations at the Fall 2003 AGU meeting (and will have one in 2004) and participated in the May 2003 GERM meeting in Lyon, France where we provided the newly established Publishers' Round Table a list of minimum standards of data reporting to ease the assimilation of data into the databases. Aspects of these suggestions already have been incorporated into new data policies at Geochimica et Cosmochimica Acta and Chemical Geology (Goldstein et al. 2004), and are under study by the Geological Society of America. EarthChem presented its objectives and activities to the Solid Earth Sciences community at the Annual GSA Meeting 2003 (Lehnert et al, 2003). Future plans for EarthChem include expanding the types and amounts of data available from a single portal, giving researchers, faculty, students, and the general public the ability to search, visualize, and download geochemical and geochronological data for a

  11. Magmatic origin of alkaline meta-igneous rocks from Chamberlindalen, SW Svalbard

    NASA Astrophysics Data System (ADS)

    Goluchowska, Karolina; Barker, Abigail; Manecki, Maciej; Czerny, Jerzy; Majka, Jaroslaw

    2014-05-01

    This study focuses on the late Neoproterozoic meta-igneous rocks of SW Svalbard to determine their magmatic evolution, conditions of magma storage and origin. The samples from the Chamberlindalen area form an alkaline igneous suite, from which thin dikes and intrusive bodies have been collected. The rocks in question intrude Late Neoproterozoic metasediments and are surrounded by occurrences of Neoproterozoic metabasalts in contrast to highly alkaline the Chamberlindalen intrusions. The rocks from Chamberlindalen are divided into two groups based on their geochemistry, mineralogy and field relationships. The dikes, classify as minettes, belonging to the lamprophyre group and contain mainly euhedral, elongated phlogopite and additionally clinopyroxene and feldspar. The rest of the samples are highly magnesian and are classified as alkali gabbro. The alkali gabbros contain primary magmatic minerals such as clinopyroxene, calcic amphibole and mica in different proportions. The alkali gabbros are enriched in LREE and HFSE and depleted in P, K and HREE. The minette dikes are always more enriched in HFSE and REE in comparison to the alkali gabbros. The mineral chemistry of the alkali gabbros reveals that pyroxenes are represented by diopside with Wo46-51 En35-46 Fs6-14, and calcic amphibole by kaersutite. The Mg# number for diopside is from 72 - 88, whereas for kaersutite Mg# number is 51 - 74. Thermobarometry calculations for diopside and kaersutite have been performed. In the alkali gabbros from Chamberlindalen, diopside crystallized between 0.7 - 8 kbar and 1152 - 1233°C. Results for kaersutite reveal that they crystallized between 5 - 17 kbar and 1043 - 1215°C. For diopside the main crystallization was between 10 and 38 km, whereas for kaersutite, the main crystallization was between 30 and 50 km. Clinopyroxene and minor kaersutite also show a zone of crystallization at 2 to 10 km. This reflects a main crystallization zone at 10 - 50 km throughout the continental

  12. {beta}-decay half-lives and {beta}-delayed neutron emission probabilities of nuclei in the region A < or approx. 110, relevant for the r process

    SciTech Connect

    Pereira, J.; Galaviz, D.; Matos, M.; Montes, F.; Hennrich, S.; Kessler, R.; Schertz, F.; Aprahamian, A.; Quinn, M.; Woehr, A.; Arndt, O.; Pfeiffer, B.; Becerril, A.; Elliot, T.; Estrade, A.; Lorusso, G.; Schatz, H.; Kratz, K.-L.; Mantica, P. F.; Moeller, P.

    2009-03-15

    Measurements of {beta}-decay properties of A < or approx. 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr, and {sup 111}Mo, along with {beta}-delayed neutron emission probabilities of {sup 104}Y, {sup 109,110}Mo and upper limits for {sup 105}Y, {sup 103-107}Zr, and {sup 108,111}Mo have been measured for the first time. Studies on the basis of the quasi-random-phase approximation are used to analyze the ground-state deformation of these nuclei.

  13. Beta-decay half-lives and beta-delayed neutron emisison probabilities of nuclei in the region A. 110, relevant for the r-process

    SciTech Connect

    Moller, Peter; Pereira, J; Hennrich, S; Aprahamian, A; Arndt, O; Becerril, A; Elliot, T; Estrade, A; Galaviz, D; Kessler, R; Kratz, K - L; Lorusso, G; Mantica, P F; Matos, M; Montes, F; Pfeiffer, B; Schatz, F; Schnorrenberger, L; Smith, E; Stolz, A; Quinn, M; Walters, W B; Wohr, A

    2009-01-01

    Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to analyze the ground-state deformation of these nuclei.

  14. Rheology Of MonoSodium Titanate (MST) And Modified Mst (mMST) Mixtures Relevant To The Salt Waste Processing Facility

    SciTech Connect

    Koopman, D. C.; Martino, C. J.; Shehee, T. C.; Poirier, M. R.

    2013-07-31

    The Savannah River National Laboratory performed measurements of the rheology of suspensions and settled layers of treated material applicable to the Savannah River Site Salt Waste Processing Facility. Suspended solids mixtures included monosodium titanate (MST) or modified MST (mMST) at various solid concentrations and soluble ion concentrations with and without the inclusion of kaolin clay or simulated sludge. Layers of settled solids were MST/sludge or mMST/sludge mixtures, either with or without sorbed strontium, over a range of initial solids concentrations, soluble ion concentrations, and settling times.

  15. Central Appalachian Valley and Ridge Province Cenozoic igneous activity and its relation in space and time with the Late Jurassic rift-to-drift-related alkalic dikes

    NASA Astrophysics Data System (ADS)

    Meyer, R.; Schultz, L.; Hendriks, B. W.; Harbor, D. J.; Connors, C. D.

    2011-12-01

    A Swarm of Late Jurassic alkalic intrusions, geographically limited mainly to the Augusta County in western Virginia has been studied geochemically. These dykes were emplaced along a northwest-southeast cross-strike basement fracture zone during Mesozoic extension. However, not all igneous rocks in Virginia are Jurassic; published K-Ar ages already suggested an Eocene age activity around Monterey, VA. We systematically sampled and studied these rocks geochemically and used the Ar-Ar dating technique to define a more precise age for this youngest volcanic activity East of the Mississippi. The younger igneous bodies have traditionally been interpreted as intrusive bodies representing old plumbing systems of eroded volcanic centers. This hypothesis is based on studies of aphanitic to porphyritic and occasionally vesicular hard rocks from quarries and road cuts. Pyroclastic deposits have mainly been neglected during theses earlier studies. However additional petrographic studies of volcanic sediments are able to shed light not only on the volcanic nature of these pyroclastic rocks but also on eruption mechanisms and magma crust interactions. Our petrographic studies indicate that these volcanic sediments contain different clasts of igneous and sedimentary country rocks (sandstones and limestones of different formations), fresh glass shards and crystals of predominantly pyroxene, hornblende and micas. A previously unmapped, massive, m-thick andesitic pyroclastic deposit has been studied in detail to shed light on the formation of theses volcanic sediments. Field relations and observations (e.g. denser rock fragments are enriched in the lower part of the sequence and bedding is largely parallel to the present topography) are consistent with a massive welded ignimbrite. As a result, surface erosion after the eruption must be less significant than previously believed and some rocks are clearly volcanic in nature. Petrogenetically the Jurassic magmas are much more alkalic

  16. Central Appalachian Valley and Ridge Province Cenozoic igneous activity and their relation in space and time with the Late Jurassic rift to drift related alkalic dikes.

    NASA Astrophysics Data System (ADS)

    Meyer, R.; Schultz, L.; Hendriks, B. W. H.; Harbor, D.; van Wijk, J.; Connors, C.

    2012-04-01

    A Swarm of Late Jurassic alkalic intrusions and geographically limited mainly to the Augusta County in western Virginia has been studied geochemically. These dykes were emplaced along a northwest-southeast cross-strike basement fracture zone during Mesozoic extension. However, not all igneous rocks in Virginia are Jurassic; published K-Ar ages already suggested an Eocene age activity around Monterey, VA (e.g. Fullagar & Bottino 1969). We first systematically sampled and studied these rocks geochemically and used the Ar-Ar dating technique to define a more precise age (around 48Ma) for this youngest volcanic activity East of the Mississippi. The younger igneous bodies have traditionally been interpreted as intrusive bodies representing old plumbing systems of eroded volcanic centers. This hypothesis is based on studies of aphanitic to porphyritic and occasionally vesicular hard rocks from quarries and road cuts. Pyroclastic deposits have mainly been neglected during theses earlier studies. However additional petrographic studies of volcanic sediments are able to shed light not only on the volcanic nature of these pyroclastic rocks but also on eruption mechanisms and magma crust interactions. Our petrographic studies defined that these volcanic sediments contain different clasts of igneous and sedimentary country rocks (sandstones and limestones of different formations), fresh glass shards and crystals of predominantly pyroxene, hornblende and micas. A previously unmapped, massive, m-thick andesitic pyroclastic deposit has been studied in detail to shed light on the formation of theses volcanic sediments. Field relations and observations (e.g.denser rock fragments are enriched in the lower part of the sequence and bedding is largely parallel to the present topography) are consistent with a massive welded ignimbrite. As a result, surface erosion after the eruption must be less significant than previously believed and some rocks are clearly volcanic in nature

  17. 3D seismic interpretation of subsurface eruptive centers in a Permian large igneous province, Tazhong Uplift, central Tarim Basin, NW China

    NASA Astrophysics Data System (ADS)

    Yang, Jiangfeng; Zhu, Wenbin; Guan, Da; Zhu, Beibei; Yuan, Liansheng; Xiang, Xuemei; Su, Jinbao; He, Jingwen; Wu, Xinhui

    2015-12-01

    A 1445-km2 high-resolution 3D seismic reflection dataset is used to analyze the Permian large igneous province in the subsurface of the Tazhong area in the central Tarim Basin in northwestern China. Constrained by the synthetic seismograms of four wells, the top and base of the igneous rocks were identified in the seismic data. Seven large volcanic craters, each >10 km2 in area, have been discovered via the application of coherency and amplitude attributes. The thickness and volume of the igneous rocks were obtained by time-depth transformation. In the study area, all of the igneous rocks, with thicknesses from 120 to 1133 m, were formed by eruptions in the Early Permian. These events produced huge erupted volumes (178 km3) and multiple closely spaced volcanic edifices (<13 km). These features suggest that the study area may be the part of the eruptive center of the Permian igneous rocks in the Tarim Basin.

  18. Non-canonical uracil processing in DNA gives rise to double-strand breaks and deletions: relevance to class switch recombination.

    PubMed

    Bregenhorn, Stephanie; Kallenberger, Lia; Artola-Borán, Mariela; Peña-Diaz, Javier; Jiricny, Josef

    2016-04-01

    During class switch recombination (CSR), antigen-stimulated B-cells rearrange their immunoglobulin constant heavy chain (CH) loci to generate antibodies with different effector functions. CSR is initiated by activation-induced deaminase (AID), which converts cytosines in switch (S) regions, repetitive sequences flanking the CH loci, to uracils. Although U/G mispairs arising in this way are generally efficiently repaired to C/Gs by uracil DNA glycosylase (UNG)-initiated base excision repair (BER), uracil processing in S-regions of activated B-cells occasionally gives rise to double strand breaks (DSBs), which trigger CSR. Surprisingly, genetic experiments revealed that CSR is dependent not only on AID and UNG, but also on mismatch repair (MMR). To elucidate the role of MMR in CSR, we studied the processing of uracil-containing DNA substrates in extracts of MMR-proficient and -deficient human cells, as well as in a system reconstituted from recombinant BER and MMR proteins. Here, we show that the interplay of these repair systems gives rise to DSBs in vitro and to genomic deletions and mutations in vivo, particularly in an S-region sequence. Our findings further suggest that MMR affects pathway choice in DSB repair. Given its amenability to manipulation, our system represents a powerful tool for the molecular dissection of CSR. PMID:26743004

  19. Vascular Wall-Resident Multipotent Stem Cells of Mesenchymal Nature within the Process of Vascular Remodeling: Cellular Basis, Clinical Relevance, and Implications for Stem Cell Therapy

    PubMed Central

    Klein, Diana

    2016-01-01

    Until some years ago, the bone marrow and the endothelial cell compartment lining the vessel lumen (subendothelial space) were thought to be the only sources providing vascular progenitor cells. Now, the vessel wall, in particular, the vascular adventitia, has been established as a niche for different types of stem and progenitor cells with the capacity to differentiate into both vascular and nonvascular cells. Herein, vascular wall-resident multipotent stem cells of mesenchymal nature (VW-MPSCs) have gained importance because of their large range of differentiation in combination with their distribution throughout the postnatal organism which is related to their existence in the adventitial niche, respectively. In general, mesenchymal stem cells, also designated as mesenchymal stromal cells (MSCs), contribute to the maintenance of organ integrity by their ability to replace defunct cells or secrete cytokines locally and thus support repair and healing processes of the affected tissues. This review will focus on the central role of VW-MPSCs within vascular reconstructing processes (vascular remodeling) which are absolute prerequisite to preserve the sensitive relationship between resilience and stability of the vessel wall. Further, a particular advantage for the therapeutic application of VW-MPSCs for improving vascular function or preventing vascular damage will be discussed. PMID:26880936

  20. Non-canonical uracil processing in DNA gives rise to double-strand breaks and deletions: relevance to class switch recombination

    PubMed Central

    Bregenhorn, Stephanie; Kallenberger, Lia; Artola-Borán, Mariela; Peña-Diaz, Javier; Jiricny, Josef

    2016-01-01

    During class switch recombination (CSR), antigen-stimulated B-cells rearrange their immunoglobulin constant heavy chain (CH) loci to generate antibodies with different effector functions. CSR is initiated by activation-induced deaminase (AID), which converts cytosines in switch (S) regions, repetitive sequences flanking the CH loci, to uracils. Although U/G mispairs arising in this way are generally efficiently repaired to C/Gs by uracil DNA glycosylase (UNG)-initiated base excision repair (BER), uracil processing in S-regions of activated B-cells occasionally gives rise to double strand breaks (DSBs), which trigger CSR. Surprisingly, genetic experiments revealed that CSR is dependent not only on AID and UNG, but also on mismatch repair (MMR). To elucidate the role of MMR in CSR, we studied the processing of uracil-containing DNA substrates in extracts of MMR-proficient and –deficient human cells, as well as in a system reconstituted from recombinant BER and MMR proteins. Here, we show that the interplay of these repair systems gives rise to DSBs in vitro and to genomic deletions and mutations in vivo, particularly in an S-region sequence. Our findings further suggest that MMR affects pathway choice in DSB repair. Given its amenability to manipulation, our system represents a powerful tool for the molecular dissection of CSR. PMID:26743004

  1. Comparative Molecular Dynamics Study on Tri-n-butyl Phosphate in Organic and Aqueous Environments and Its Relevance to Nuclear Extraction Processes.

    PubMed

    Mu, Junju; Motokawa, Ryuhei; Williams, Christopher D; Akutsu, Kazuhiro; Nishitsuji, Shotaro; Masters, Andrew J

    2016-06-16

    A refined model for tri-n-butyl phosphate (TBP), which uses a new set of partial charges generated from our ab initio density functional theory calculations, has been proposed in this study. Molecular dynamics simulations are conducted to determine the thermodynamic properties, transport properties, and the microscopic structures of liquid TBP, TBP/water mixtures, and TBP/n-alkane mixtures. These results are compared with those obtained from four other TBP models, previously described in the literature. We conclude that our refined TBP model appears to be the only TBP model from this set that, with reasonable accuracy, can simultaneously predict the properties of TBP in bulk TBP, in organic diluents, and in aqueous solution. The other models only work well for two of the three systems mentioned above. This new TBP model is thus appropriate for the simulation of liquid-liquid extraction systems in the nuclear extraction process, where one needs to simultaneously model TBP in both aqueous and organic phases. It is also promising for the investigation of the microscopic structure of the organic phase in these processes and for the characterization of third-phase formation, where TBP again interacts simultaneously with both polar and nonpolar molecules. Because the proposed TBP model uses OPLS-2005 Lennard-Jones parameters, it may be used with confidence to model mixtures of TBP with other species whose parameters are given by the OPLS-2005 force field. PMID:27192017

  2. In situ Detection of Microbial Life in the Deep Biosphere in Igneous Ocean Crust

    PubMed Central

    Salas, Everett C.; Bhartia, Rohit; Anderson, Louise; Hug, William F.; Reid, Ray D.; Iturrino, Gerardo; Edwards, Katrina J.

    2015-01-01

    The deep biosphere is a major frontier to science. Recent studies have shown the presence and activity of cells in deep marine sediments and in the continental deep biosphere. Volcanic lavas in the deep ocean subsurface, through which substantial fluid flow occurs, present another potentially massive deep biosphere. We present results from the deployment of a novel in situ logging tool designed to detect microbial life harbored in a deep, native, borehole environment within igneous oceanic crust, using deep ultraviolet native fluorescence spectroscopy. Results demonstrate the predominance of microbial-like signatures within the borehole environment, with densities in the range of 105 cells/mL. Based on transport and flux models, we estimate that such a concentration of microbial cells could not be supported by transport through the crust, suggesting in situ growth of these communities. PMID:26617595

  3. Evolution of KREEP - Further petrologic evidence. [igneous rocks from Apollo 15 site

    NASA Technical Reports Server (NTRS)

    Crawford, M. L.; Hollister, L. S.

    1977-01-01

    It is hypothesized that KREEP samples from the Apollo 15 site are igneous. To support the hypothesis, comparisons are made with other crystalline KREEP samples, especially 14310. It is noted that the low siderophile element content and lack of high pressure phenocrysts in the Apollo 15 KREEP may be indications of a slower rise of KREEP melt to the surface, when contrasted with sample 14310. Gravitational separation of Fe-Ni metal is proposed as a mechanism to account for the depletion of siderophile elements relative to the Si-rich component. It is further suggested that KREEP may be the parent of Apollo 12 and 15 basalts, as well as of granitic rocks, due to the liquid immiscibility occurring during the KREEP melt crystallization, and the subsequent independent evolution of the components.

  4. In situ Detection of Microbial Life in the Deep Biosphere in Igneous Ocean Crust.

    PubMed

    Salas, Everett C; Bhartia, Rohit; Anderson, Louise; Hug, William F; Reid, Ray D; Iturrino, Gerardo; Edwards, Katrina J

    2015-01-01

    The deep biosphere is a major frontier to science. Recent studies have shown the presence and activity of cells in deep marine sediments and in the continental deep biosphere. Volcanic lavas in the deep ocean subsurface, through which substantial fluid flow occurs, present another potentially massive deep biosphere. We present results from the deployment of a novel in situ logging tool designed to detect microbial life harbored in a deep, native, borehole environment within igneous oceanic crust, using deep ultraviolet native fluorescence spectroscopy. Results demonstrate the predominance of microbial-like signatures within the borehole environment, with densities in the range of 10(5) cells/mL. Based on transport and flux models, we estimate that such a concentration of microbial cells could not be supported by transport through the crust, suggesting in situ growth of these communities. PMID:26617595

  5. Detecting the Deep-Biosphere in-Situ within Igneous Ocean Crust

    NASA Astrophysics Data System (ADS)

    Edwards, K. J.

    2014-12-01

    The deep biosphere is a major frontier to science. Recent studies have shown the presence and activity of cells in deep marine sediments and in the continental deep biosphere. Volcanic lavas in the deep ocean subsurface, through which substantial fluid flow occurs, present another potentially massive deep biosphere. We present results from the deployment of a novel in-situ logging tool designed to detect microbial life harbored in a deep, native, borehole environment within igneous oceanic crust, using deep ultraviolet native fluorescence spectroscopy. Results demonstrate the predominance of microbial-like signatures within the borehole environment, with densities in the range of 105 cells/mL. Based on transport and flux models, we estimate that such a concentration of microbial cells could not be supported by transport through the crust, suggesting in situ growth of these communities.

  6. Age and composition of igneous rocks, Edna Mountain quadrangle, Humboldt County, Nevada

    USGS Publications Warehouse

    Erickson, Ralph L.; Silberman, Miles L.; Marsh, S.P.

    1978-01-01

    Six pulses of igneous activity ranging in age from Jurassic to Pliocene have been identified in the Edna Mountain quadrangle, Humboldt County, Nev. Porphyritic syenite am! quartz monzonite of Jurassic age (146-164 million years) at Buffalo Mountain are highly potassic through a wide range in SiO2 content from olivine-bearing syenite to quartz-rich monzonite, and their composition contrasts sharply with plutons elsewhere in north-central Nevada. Granodiorite and quartz monzonite plutons of Cretaceous age (88- 106 m.y.) are chemically and mineralogically similar to other calc-alkaline plutons in north-central Nevada. Four episodes of Tertiary volcanism include rhyolite ashflow tuffs and slightly younger andesitic basalt flows and tuffs of Oligocene age, rhyolite vitrophyre of late Miocene age, and olivine basalt flows of Pliocene age. Their age and mineralogical and chemical compositions are similar to other Tertiary volcanic rocks in north-central Nevada.

  7. Thermal-infrared spectra and chemical analyses of twenty-six igneous rock samples

    USGS Publications Warehouse

    Vincent, R.K.; Rowan, L.C.; Gillespie, R.E.; Knapp, C.

    1975-01-01

    Emittance spectra in the 7.5 ??m to 14 ??m wavelength region and chemical compositions of 26 igneous rocks are reported. Experimental measurements on the rocks were made under simulated daytime field conditions. Some surface silicate contaminants, such as clayey silt, significantly altered the spectral emittance of a fresh sample, whereas, for these samples, hydrous and anhydrous ferric oxide weathering products did not mask important silicate spectral information. In the 11.75 ??m to 13.75 ??m wavelength region, the mean emittance of all the silicate samples was 0.956 ?? 0.008, except for periodtite, which had an average emittance of 0.895. This region of uniform emittance should be useful in remote sensing experiments for the separation of the effects of temperature and chemical composition on the spectral emittance of silicate rocks. ?? 1976.

  8. Relationships between gas geochemistry and release rates and the geomechanical state of igneous rock massifs

    NASA Astrophysics Data System (ADS)

    Nivin, Valentin A.; Belov, Nikolai I.; Treloar, Peter J.; Timofeyev, Vladimir V.

    2001-07-01

    In contrast to sedimentary sequences, the relationships between the stressed state of igneous rocks and the chemistry and physical properties of gases contained within them are not well known. Here, we attempt to fill this gap by using, as an example, the apatite-nepheline and rare-metal ore deposits hosted within the Khibiny and Lovozero alkaline nepheline-syenite complexes of the Kola Peninsula, NW Russia. These massifs are characterized by unusually high, for igneous rocks, contents of multi-component, essentially hydrogen-hydrocarbon, gases and also by high hardness, elasticity and unevenly distributed, subhorizontal tectonic stresses. Relationships between the chemical and dynamic characteristics of the gases and the geomechanical properties of the host rocks have been examined using field observations and laboratory experiments. Patterns of gas release variations in time and space, gas emissions from rock pillars during artificial loading, variations of gas pressure in sealed shot-holes and changes in liberation rates of gaseous components during experimental rock loading are suggested to result from changes in rock stress and deformation state. Gas compositions in sealed shot-holes in stressed rocks change with time. Partly, this is due to belated release of gases held in fluid inclusions and isolated voids and their subsequent mixing with gases held in interconnected fracture systems as the included gases are preferentially released as fluid inclusion arrays are opened during later stages of stress build-up. Partly, it may also be because released gases may react with new fracture surfaces to generate enhanced levels of reduced H 2 gases.

  9. Reassembling the Ontong Java-Manihiki-Hikurangi large igneous province: Insights and challenges

    NASA Astrophysics Data System (ADS)

    Chandler, M. T.; Wessel, P.; Taylor, B.; Sager, W. W.

    2012-12-01

    The tectonic history of ~30% of the Pacific plate south of Equator which formed during the Cretaceous Normal Supercron is difficult to establish due to its lack of a lineated magnetic anomaly pattern. This region, including the Ontong Java, Manihiki, and Hikurangi large igneous provinces, as well as the interlying Ellice Basin and Osbourn Trough, lacks active seafloor spreading centers and has thus been largely neglected by seagoing research scientists. Nonetheless, the CNS South Pacific may prove to be important for understanding Pacific history. Ontong Java's mean basement paleolatitude measurement differs from absolute plate model (APM) reconstructions for the plateau by ~8--19 degrees (Chandler et al. (2012)), indicating that either current APM models are erroneous, substantial plume drift or true polar wander occurred, or that Ontong Java experienced unrecognized motion early in its history. In support of the latter are recent findings that little to no Louisville plume drift occurred after ~70 Ma (Gee et al. (2011)), that true polar wander estimates for the ~125 Ma Ontong Java vicinity are negligible (Steinberger and Torsvik (2008)), and our recent observation of a 2:1 bias between Ontong Java's paleolatitude and latitude differences (Chandler and Wessel (2011), Chandler et al. (In prep)). These differences, computed among ODP Sites 807 and 1183 - 1187, suggest significant clockwise rotation of ~40 degrees since Ontong Java's formation at ~125 Ma. Although this rotation does not resolve the paleolatitude discrepancy it does suggest that Ontong Java's paleolatitudes may not be suitable for constraining Pacific APM. Seafloor formed at the Osbourn Trough and in the Ellice Basin make up much of the CNS South Pacific. These regions exhibit fossil spreading centers believed responsible for the breakup of Earth's largest known igneous province, the Ontong Java-Manihiki-Hikurangi super-plateau (e.g., Taylor (2006), Chandler et al. (2012)). Understanding this little

  10. A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust

    PubMed Central

    Ivarsson, Magnus; Bengtson, Stefan; Skogby, Henrik; Lazor, Peter; Broman, Curt; Belivanova, Veneta; Marone, Federica

    2015-01-01

    We have after half a century of coordinated scientific drilling gained insight into Earth´s largest microbial habitat, the subseafloor igneous crust, but still lack substantial understanding regarding its abundance, diversity and ecology. Here we describe a fossilized microbial consortium of prokaryotes and fungi at the basalt-zeolite interface of fractured subseafloor basalts from a depth of 240 m below seafloor (mbsf). The microbial consortium and its relationship with the surrounding physical environment are revealed by synchrotron-based X-ray tomographic microscopy (SRXTM), environmental scanning electron microscopy (ESEM), and Raman spectroscopy. The base of the consortium is represented by microstromatolites—remains of bacterial communities that oxidized reduced iron directly from the basalt. The microstromatolites and the surrounding basalt were overlaid by fungal cells and hyphae. The consortium was overgrown by hydrothermally formed zeolites but remained alive and active during this event. After its formation, fungal hyphae bored in the zeolite, producing millimetre-long tunnels through the mineral substrate. The dissolution could either serve to extract metals like Ca, Na and K essential for fungal growth and metabolism, or be a response to environmental stress owing to the mineral overgrowth. Our results show how microbial life may be maintained in a nutrient-poor and extreme environment by close ecological interplay and reveal an effective strategy for nutrient extraction from minerals. The prokaryotic portion of the consortium served as a carbon source for the eukaryotic portion. Such an approach may be a prerequisite for prokaryotic-eukaryotic colonisation of, and persistence in, subseafloor igneous crust. PMID:26488482

  11. The Basal Onaping Intrusion in the North Range: Roof rocks of the Sudbury Igneous Complex

    NASA Astrophysics Data System (ADS)

    Anders, Denise; Osinski, Gordon R.; Grieve, Richard A. F.; Brillinger, Derek T. M.

    2015-09-01

    The 1.85 Ga Sudbury impact structure is one of the largest impact structures on Earth. Igneous bodies—the so-called "Basal Onaping Intrusion"—occur at the contact between the Sudbury Igneous Complex (SIC) and the overlying Onaping Formation and occupy ~50% of this contact zone. The Basal Onaping Intrusion is presently considered part of the Onaping Formation, which is a complex series of breccias. Here, we present petrological and geochemical data from two drill cores and field data from the North Range of the Sudbury structure, which suggests that the Basal Onaping Intrusion is not part of the Onaping Formation. Our observations indicate that the Basal Onaping Intrusion crystallized from a melt and has a groundmass comprising a skeletal intergrowth of feldspar and quartz that points to simultaneous cooling of both components. Increasing grain size and decreasing amounts of clasts with increasing depth are general features of roof rocks of coherent impact melt rocks at other impact structures and the Basal Onaping Intrusion. Planar deformation features within quartz clasts of the Basal Onaping Intrusion are indicators for shock metamorphism and, together with the melt matrix, point to the Basal Onaping Intrusion as being an impact melt rock, by definition. Importantly, the contact between Granophyre of the SIC and Basal Onaping Intrusion is transitional and we suggest that the Basal Onaping Intrusion is what remains of the roof rocks of the SIC and, thus, is a unit of the SIC and not the Onaping Formation. We suggest henceforth that this unit be referred to as the "Upper Contact Unit" of the SIC.

  12. Fixed Hot-spots Gone With Wind? Clues From Paleomagnetic Investigations of Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Ernesto, M.

    2013-05-01

    Paleomagnetic studies of Ocean Drilling Program (ODP) 197 on samples from the Emperor-Hawaiian seamount chain suggested that these rocks formed much farther north than the hotspot currently beneath Hawaii. These findings indicate that the hotspot, once thought to be fixed beneath the Earth's crust, actually jumped southward rapidly. Here we report paleomagnetic evidence that is consistence with these findings and suggests that rapid hotspots motion (also southward jumps) occurred while the massive Ontong Java (OJP), Kerguelen Plateau (KP), and Parana Magmatic Province (PMP) large igneous provinces formed. The paleomagnetic paleolatitude for the OJP is ~20 farther north than those predicted by the Louisville hotspot model. The difference between the paleomagnetic and hotspot calculated paleolatitudes cannot be explained by true polar wander estimates derived from other lithospheric plates. Our results are therefore consistent with and extend the Emperor-Hawaiian hotspot features in the northern Pacific Ocean that suggest Late Cretaceous to Eocene motion of Pacific hotspots. Compared to the latitude of the Kerguelen hotspot, the paleolatitudes of the central and northern Kerguelen Plateau obtained by ODP Leg 183 are further north. This difference also indicates a southward movement of the Kerguelen hotspot since the Cretaceous relative to the spin axis of the Earth. Numerical modeling of plume conduit motion in a large-scale mantle flow also predicts southward motion of the Kerguelen hotspot, which is consistent with paleomagnetic results. Likewise, paleomagnetic results from PMP reveal significant southward movement of the Tristan da Cunha hotspot in the Cretaceous. Elucidating how large igneous province formation and mantle dynamics are related and whether hotspots moved at comparable rates during other times are challenges for future research.

  13. Taos Plateau Volcanic Project: A Vehicle for Integration of Concepts in Igneous Petrology

    NASA Astrophysics Data System (ADS)

    Henry, D.; Dutrow, B.

    2003-12-01

    Integrating concepts of igneous petrology is generally a challenge, but can be effective in the context of a project based on actual field, geochemical and geochronological data. The final lab project in the igneous portion of petrology involves a series of volcanic and associated rock samples that were collected from the Taos Plateau Volcanic Field, New Mexico, USA. Samples were collected over an area of several tens of km2 throughout the Plateau and represent a spatially and temporally correlated rock suite related to continental rifting. Rift-related magmatism encompasses much of the diversity of terrestrial magma types. Compositions of mafic magmas range from tholeiite to some of the most silica-undersaturated magmas found on the continents. Large effusive eruptions from fissures are typical of some rifts, whereas others may be dominated by central vent cones or even silicic caldera complexes. The injection of mantle-derived magma in extending crust may have a profound effect on the rheology of the crust and, therefore, the style of deformation associated with extension. Most of these aspects of rift volcanism and a wide range of mafic to silicic magma compositions are represented in the Rio Grande rift and the volcanic rocks of the Taos Plateau. In addition, much published data exists for whole rock and trace element geochemistry as well as geochronology. Rock samples and associated information are presented so that the student must integrate multiple lines of evidence, petrographic, petrologic, geochemical and geochronological data in a geospatial framework, to establish a geologic history of the region. The student must also draw on skills learned in mineralogy and structural geology furthering core geoscience education. Subsequent to the petrology course, the students visit the Taos Plateau Volcanic Field during their required field camp, thus reinforcing the linkage between the classroom setting and geologic reality.

  14. Application of spatially weighted Technology for mapping intermediate and felsic igneous rocks in Fujian Province, China

    NASA Astrophysics Data System (ADS)

    Zhang, Daojun

    2016-04-01

    Magmatic activity is of great significance to mineralization not only for heat and fluid it provides, but also for parts of material source it brings. Due to the cover of soil and vegetation and its spatial nonuniformity detected singals from the ground's surface may be weak and of spatial variability, and this brings serious challenges to mineral exploration in these areas. Two models based on spatially weighted technology, i.e., local singularity analysis (LSA) and spatially weighted logistic regression (SWLR) are applied in this study to deal with this challenge. Coverage cannot block the migration of geochemical elements, it is possible that the geochemical features of soil above concealed rocks can be different from surrounding environment, although this kind of differences are weak; coverage may also weaken the surface expression of geophysical fields. LSA is sensitive to weak changes in density or energy, which makes it effective to map the distribution of concealed igneous rock based on geochemical and geophysical properties. Data integration can produce better classification results than any single data analysis, but spatial variability of spatial variables caused by non-stationary coverage can greatly affect the results since sometimes it is hard to establish a global model. In this paper, SWLR is used to integrate all spatial layers extracted from both geochemical and geophysical data, and the iron polymetallic metallogenic belt in sours-west of Fujian Province is used as s study case. It is found that LSA technique effectively extracts different sources of geologic anomalies; and the spatial distribution of intermediate and felsic igneous rocks delineated by SWLR shows higher accuracy compared with the result obtained via global model.

  15. Evidence of prolonged felsic magmatism within the Karoo large igneous province

    NASA Astrophysics Data System (ADS)

    Kurhila, Matti; Romu, Ilona; Mänttäri, Irmeli; Andersen, Tom; Luttinen, Arto

    2015-04-01

    The Karoo large igneous province (LIP) extends from southern Africa to East Antarctica, and marks the onset of rifting of these two continents. The main stage of volcanic activity occurred ~182180 Ma ago, and was mostly mafic in composition. We report new thermal ionization (TIMS) and secondary ion (SIMS) mass spectrometric U-Pb ages on zircon from felsic lavas in Lebombo monocline, southern Mozambique and from granitoid intrusions in Vestfjella, Dronning Maud Land, Antarctica. Utpostane granite in southern Vestfjella yields a TIMS age of 180.7±1.5 Ma, complying with the main stage of magmatism in the Karoo LIP. Three rhyolitic beds intercalating mafic volcanic layers of the Lebombo monocline give SIMS ages of 182±3 Ma, 178±3 Ma, and 172±2 Ma, respectively. The zircon in the oldest of these can be divided in two groups: (a) internally homogeneous, low U and Pb zircon and (b) oscillatorily zoned, relatively high U and Pb zircon. The ages of these groups are ~179 Ma and ~184 Ma, respectively, but they overlap within error limits, and thus a combined age for this sample is preferred. Finally, an alkali feldspar granite xenolith from a lamproite dike in Vestfjella has a SIMS age of 165±1 Ma. Lu-Hf isotopes were analyzed from zircons in the 172 Ma rhyolite sample. They show fairly homogeneous Hf isotope composition, with initial ɛHf values between +4 and +10. The corresponding crustal residence ages for the zircons vary between ~300 and ~500 Ma, implying source recycling. In light of the new data it is thus evident that, while most of the Karoo LIP may have emplaced within a short time frame, igneous activity continued for at least ~15 Ma.

  16. Deep structure of the Mount Amram igneous complex, interpretation of magnetic and gravity data

    NASA Astrophysics Data System (ADS)

    Shirman, Boris; Rybakov, Michael; Beyth, Michael; Mushkin, Amit; Ginat, Hanan

    2015-03-01

    The Mt Amram igneous complex (AIC) represents northern tip of the Neoproterozoic Arabian Nubian Shield (ANS). For the first time the AIC deep structure was studied using the gravity, aero and ground magnetic, magnetic susceptibility and density measurements and geological data. Analysing all available data at the Amram area we concluded what only monzonite body can be reason for gravity high and coinciding reduced to pole (RTP) maximum. Geological knowledge allowed suggesting its intrusive character and compact body form. Cluster of inverse solutions (Werner deconvolution) localized this body as initial model for forward modelling. Further iterations (23/4-D forward modelling) clarified the monzonite geometry and properties; the modelling allowed also to investigate the non-uniqueness and estimate also the confident intervals for final solution. The research consists three interconnected stages. At the detailed scale, ground magnetic data suggested three magmatic blocks of few hundred meters shifted dextral about 100 m along the Zefunut fault. Estimated accuracy for geometry of the magnetic bodies is a few tens metres. At the middle scale, quantitative gravity and magnetic interpretations provide model of the monzonite body, which is an order of magnitude more than the volume of the felsic rhyolites and granite rocks. Boundary of the whole monzonite body was estimated with accuracy as a hundred meters. As a result we suggest that the parent magma for the AIC is the monzonite, similar to the model suggested for the Timna Igneous Complex 12 km north of the AIC. The model developed can be applied to evaluate the subsurface volumes of the mafic magmatic rocks in adjacent locations. At the regional scale for exposed the Sinai and Arab Saudi Precambrian crystalline shield our approach allows to understand the apparent contradiction between geological predominantly granite composition (low magnetic rocks) and magnetic data. The aeromagnetic data show number strong

  17. A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust.

    PubMed

    Ivarsson, Magnus; Bengtson, Stefan; Skogby, Henrik; Lazor, Peter; Broman, Curt; Belivanova, Veneta; Marone, Federica

    2015-01-01

    We have after half a century of coordinated scientific drilling gained insight into Earth´s largest microbial habitat, the subseafloor igneous crust, but still lack substantial understanding regarding its abundance, diversity and ecology. Here we describe a fossilized microbial consortium of prokaryotes and fungi at the basalt-zeolite interface of fractured subseafloor basalts from a depth of 240 m below seafloor (mbsf). The microbial consortium and its relationship with the surrounding physical environment are revealed by synchrotron-based X-ray tomographic microscopy (SRXTM), environmental scanning electron microscopy (ESEM), and Raman spectroscopy. The base of the consortium is represented by microstromatolites-remains of bacterial communities that oxidized reduced iron directly from the basalt. The microstromatolites and the surrounding basalt were overlaid by fungal cells and hyphae. The consortium was overgrown by hydrothermally formed zeolites but remained alive and active during this event. After its formation, fungal hyphae bored in the zeolite, producing millimetre-long tunnels through the mineral substrate. The dissolution could either serve to extract metals like Ca, Na and K essential for fungal growth and metabolism, or be a response to environmental stress owing to the mineral overgrowth. Our results show how microbial life may be maintained in a nutrient-poor and extreme environment by close ecological interplay and reveal an effective strategy for nutrient extraction from minerals. The prokaryotic portion of the consortium served as a carbon source for the eukaryotic portion. Such an approach may be a prerequisite for prokaryotic-eukaryotic colonisation of, and persistence in, subseafloor igneous crust. PMID:26488482

  18. Binding potencies of 3 new beta 2 specific blockers to beta receptors in the ciliary processes and the possible relevance of these drugs to intraocular pressure control.

    PubMed Central

    Trope, G E; Clark, B

    1984-01-01

    The binding potencies of 3 new beta 2 blocking drugs to beta receptors in the ciliary processes were studied by means of radioligand techniques. The drugs studied were IPS339, ICI118,551, and Sandoz L1 32-468. The order of potency of these drugs was IPS339 greater than Sandoz L1 32-468 greater than ICI118,551. The beta 2 dissociation constants (KDs) for these drugs were 0.90 nM, 6.60 nM, and 55 nM respectively. These results are compared with those for other adrenergic agents, including timolol. The potential role of topical beta 2 blockers in glaucoma is discussed. PMID:6142724

  19. Petrological and geochemical Highlights in the floating fragments of the October 2011 submarine eruption offshore El Hierro (Canary Islands): Relevance of submarine hydrothermal processes

    NASA Astrophysics Data System (ADS)

    Rodriguez-Losada, Jose A.; Eff-Darwich, Antonio; Hernandez, Luis E.; Viñas, Ronaldo; Pérez, Nemesio; Hernandez, Pedro; Melián, Gladys; Martinez-Frías, Jesús; Romero-Ruiz, M. Carmen; Coello-Bravo, Juan Jesús

    2015-02-01

    This paper describes the main physical, petrological and geochemical features of the floating fragments that were emitted in the initial stages of the 2011-2012 submarine eruption off the coast of the Canarian island of El Hierro, located 380 km from the Northwest African Coast. It attempts to assess the potential of radiometric analyses to discern the intriguing origin of the floating fragments and the differences between their constituent parts. In this regard, the material that conforms the core of the fragments contains the largest concentration of uranium (U) ever found in volcanic rocks of the Canary Islands. This enrichment in U is not found in the content of thorium (Th), hence the floating fragments have an unusual U/Th ratio, namely equal to or larger than 3. Although the origin of this material is under discussion, it is proposed that the enrichment in U is the result of hydrothermal processes.

  20. Studies relevant to the catalytic activation of carbon monoxide: the water gas shift reaction and related processes. Technical progress report, December 1, 1983-November 30, 1984

    SciTech Connect

    Ford, P.C.

    1984-01-01

    Proposed are investigations related to the catalytic activation of carbon monoxide. These studies will be concerned with the design of catalysts for the water gas shift reaction and related processes such as the hydroformylation of olefins by homogeneous solution phase systems as well as by selected metal catalysts heterogenized by complexation to functionalized polymers. Also under investigation will be quantitative mechanistic aspects of reactions considered key to probable catalyst cycles. These are principally concerned with the fundamental chemistry of metal carbonyl and metal carbonyl hydride complexes including acid/base properties, reductive elimination, substitution and cluster fragmentation reactions and the nucleophilic activation of metal coordinated carbonyls toward reaction with water or dihydrogen. The goal of these studies is to provide chemical guidelines for the molecular design of new and more efficient catalysts for the utilization of carbonaceous materials such as coal for the production of fuels and other organic chemicals. 70 references.

  1. Histamine H3 receptor antagonists/inverse agonists on cognitive and motor processes: relevance to Alzheimer's disease, ADHD, schizophrenia, and drug abuse

    PubMed Central

    Vohora, Divya; Bhowmik, Malay

    2012-01-01

    Histamine H3 receptor (H3R) antagonists/inverse agonists possess potential to treat diverse disease states of the central nervous system (CNS). Cognitive dysfunction and motor impairments are the hallmark of multifarious neurodegenerative and/or psychiatric disorders. This review presents the various neurobiological/neurochemical evidences available so far following H3R antagonists in the pathophysiology of Alzheimer's disease (AD), attention-deficit hyperactivity disorder (ADHD), schizophrenia, and drug abuse each of which is accompanied by deficits of some aspects of cognitive and/or motor functions. Whether the H3R inverse agonism modulates the neurochemical basis underlying the disease condition or affects only the cognitive/motor component of the disease process is discussed with the aim to provide a rationale for their use in diverse disease states that are interlinked and are accompanied by some common motor, cognitive and attentional deficits. PMID:23109919

  2. Geochemical Uniformity over 30 Million Years of Volcanic Activity in the Caribbean Large Igneous Province: Evidence from Curacao and Haiti

    NASA Astrophysics Data System (ADS)

    Loewen, M. W.; Kent, A. J.; Duncan, R. A.; Krawl, K.; Michael, P. J.; Graham, D. W.

    2012-12-01

    New 40Ar/39Ar age determinations from Caribbean Large Igneous Province (CLIP) lavas, dikes, and sills from Curacao and Haiti record almost 30 million years of volcanism, beginning at ~93 Ma and continuing until ~63 Ma, with peak activity at 93-90, 86-85, 80-76 and 66-63 Ma. A variety of rock types are apparent. Despite the significant age range evident in our sample set, which includes picritic to tholeitic pillow lavas, thick hyaloclastite sequences, and poikolitic sills, compositions show only subtle compositional differences between groups of different age. Most whole rock samples appear to derive from a similar mantle source peridotite and to have undergone a common set differentiation processes (primarily partial melting followed by fractionation of olivine, clinopyroxene, and plagioclase). The recognition of this range of ages and compositional similarities poses important questions for the extent and cause of CLIP magmatism. We present new 40Ar-39Ar ages and major and trace elements for whole rock, minerals and glass samples from throughout the exposed volcanic sections at the two locations. Hyaloclastite glasses have also been analyzed by FTIR for volatile abundances. Unlike major element compositions of whole rock samples, major element and volatile analyses of hyaloclastite glasses reveal the presence of at least three distinct magma series. In addition, variations in Cl and Cl/K suggest that differences exist in the degree to which magmatic systems interact with seawater-derived components. One He-isotopic analysis from a Haiti picrite (3He/4He = 12.3 Ra) is consistent with other isotopic evidence for a significant mantle plume contribution to CLIP construction. Future work will focus on trace element modeling to further constrain magma sources and extents of melting, and on expanding the number of samples for which we have age control.

  3. Garnet granulite xenoliths from the Northern Baltic shield- The underplated lower crust of a palaeoproterozoic large igneous province

    USGS Publications Warehouse

    Kempton, P.D.; Downes, H.; Neymark, L.A.; Wartho, J.A.; Zartman, R.E.; Sharkov, E.V.

    2001-01-01

    Garnet granulite facies xenoliths hosted in Devonian lamprophyres from the Kola Peninsula are interpreted to represent the high-grade metamorphic equivalents of continental flood tholeiites, emplaced into the Baltic Shield Archaean lower crust in early Proterozoic time. Geochronological data and similarities in major and trace element geochemistry suggest that the xenoliths formed during the same plume-related magmatic event that created a widespread Palaeoproterozoic large igneous province (LIP) at 2.4-2.5 Ga. They are, thus, the first samples of the lower crust of a Palaeo-proterozoic LIP to be studied in petrological detail. The suite includes mafic granulites (gar + cpx + rutile ?? plag ?? opx ?? phlog ?? amph), felsic granulites (plag + gar + cpx + rutile ?? qtz ?? Kspar ?? phlog ?? amph) and pyroxenites (?? phlog ?? amph), but mafic garnet granulites predominate. Although some samples are restites, there is no evidence for a predominance of magmatic cumulates, as is common for Phanerozoic lower-crustal xenolith suites. Metasediments are also absent. Phlogopite and/or amphibole occur in xenoliths of all types and are interpreted to be metasomatic in origin. The K-rich metasomatic event occurred at ?????0 Ga, and led to substantial enrichment in Rb, K, LREE/HREE, Th/U, Th/Pb and, to a lesser extent, Nb and Ti. The fluids responsible for this metasomatism were probably derived from a second plume that arrived beneath the region at this time. Evidence for partial melting of mafic crust exists in the presence of migmatitic granulites. The timing of migmatization overlaps that of metasomatism, and it is suggested that migmatization was facilitated by the metasomatism. The metamorphism, metasomatism and migmatization recorded in the Kola granulite xenoliths may be representative of the processes responsible for converting Archaean LIP-generated proto-continents into continental crust.

  4. What have we learned from deterministic geostatistics at highly resolved field sites, as relevant to mass transport processes in sedimentary aquifers?

    NASA Astrophysics Data System (ADS)

    Ritzi, Robert W.; Soltanian, Mohamad Reza

    2015-12-01

    In the method of deterministic geostatistics (sensu Isaaks and Srivastava, 1988), highly-resolved data sets are used to compute sample spatial-bivariate statistics within a deterministic framework. The general goal is to observe what real, highly resolved, sample spatial-bivariate correlation looks like when it is well-quantified in naturally-occurring sedimentary aquifers. Furthermore, it is to understand how this correlation structure, (i.e. shape and correlation range) is related to independent and physically quantifiable attributes of the sedimentary architecture. The approach has evolved among work by Rubin (1995, 2003), Barrash and Clemo (2002), Ritzi et al. (2004, 2007, 2013), Dai et al. (2005), and Ramanathan et al. (2010). In this evolution, equations for sample statistics have been developed which allow tracking the facies types at the heads and tails of lag vectors. The goal is to observe and thereby understand how aspects of the sedimentary architecture affect the well-supported sample statistics. The approach has been used to study heterogeneity at a number of sites, representing a variety of depositional environments, with highly resolved data sets. What have we learned? We offer and support an opinion that the single most important insight derived from these studies is that the structure of spatial-bivariate correlation is essentially the cross-transition probability structure, determined by the sedimentary architecture. More than one scale of hierarchical sedimentary architecture has been represented in these studies, and a hierarchy of cross-transition probability structures was found to define the correlation structure in all cases. This insight allows decomposing contributions from different scales of the sedimentary architecture, and has led to a more fundamental understanding of mass transport processes including mechanical dispersion of solutes within aquifers, and the time-dependent retardation of reactive solutes. These processes can now be

  5. Measurement of heterogeneous chemical processes relevant to aerosol surfaces and trace gases active in the marine environment. Progress report, February 1994--January 1995

    SciTech Connect

    Davidovits, P.; Worsnop, D.R.; Zahniser, M.S.; Jayne, J.T.; Kolb, C.E.

    1995-02-01

    Biogenically produced reduced sulfur compounds from the marine environment, deliver a sulfur burden to the atmosphere which is about half as large as that due to sulfur oxides produced by fossil fuel combustion. The multiphase chemical processes for these species must be understood in order to evaluate the relative roles of biogenic and combustion produced sulfur oxides over the oceans. The aim of the studies funded by the subject DOE grant is to measure parameters governing the heterogeneous chemistry of the species occurring in the marine environment. During the past year, uptake studies for the sulfur species MSA, DMSO, DMSO{sub 2}, DMS, OCS, CS{sub 2}, H{sub 2}S, and CH{sub 3}SH have been finalized. Studies of the reactive uptake of Cl{sub 2} and Br{sub 2} by Br{sup -} and I{sup -} solutions as a function of temperature have been completed. The uptake of O{sub 3} by aqueous NaI solutions has also been studied for the purpose of comparison. We have begun co-deposition studies and have obtained some preliminary results for the codeposition with ozone of DMS, DMSO, DMSO{sub 2} and MSA. For the next phase of the work, a new horizontal bubbler apparatus was designed and built and construction to improve the detection sensitivity of the apparatuses was begun. Altogether during 1994, 8 articles have been accepted for publication and 2 Ph.D. dissertations have been submitted and approved.

  6. Re-oxidation Kinetics of Flash-Reduced Iron Particles in H2-H2O(g) Atmosphere Relevant to a Novel Flash Ironmaking Process

    NASA Astrophysics Data System (ADS)

    Yuan, Zhixue; Sohn, Hong Yong; Olivas-Martinez, Miguel

    2013-12-01

    A novel flash ironmaking process based on hydrogen-containing reduction gases is under development at the University of Utah. The goal of this work was to study the possibility of the re-oxidation of iron particles in a H2-H2O gas mixture in the lower part of the flash reactor from the kinetic point of view. The last stage of hydrogen reduction of iron oxide, i.e., the reduction of wustite, is limited by equilibrium. As the reaction mixture cools down, the re-oxidation of iron could take place because of the decreasing equilibrium constant and the high reactivity of the freshly reduced fine iron particles. The effects of temperature and H2O partial pressure on the re-oxidation rate were examined in the temperature range of 823 K to 973 K (550 °C to 700 °C) and H2O contents of 40 to 100 pct. The nucleation and growth kinetics model was shown to best describe the re-oxidation kinetics. The partial pressure dependence with respect to water vapor was determined to be of first order, and the activation energy of re-oxidation reaction was 146 kJ/mol. A complete rate equation that adequately represents the experimental data was developed.

  7. Synthesis, properties, and biological activity of boranophosphate analogs of the mRNA cap: versatile tools for manipulation of therapeutically relevant cap-dependent processes

    PubMed Central

    Kowalska, Joanna; Wypijewska del Nogal, Anna; Darzynkiewicz, Zbigniew M.; Buck, Janina; Nicola, Corina; Kuhn, Andreas N.; Lukaszewicz, Maciej; Zuberek, Joanna; Strenkowska, Malwina; Ziemniak, Marcin; Maciejczyk, Maciej; Bojarska, Elzbieta; Rhoads, Robert E.; Darzynkiewicz, Edward; Sahin, Ugur; Jemielity, Jacek

    2014-01-01

    Modified mRNA cap analogs aid in the study of mRNA-related processes and may enable creation of novel therapeutic interventions. We report the synthesis and properties of 11 dinucleotide cap analogs bearing a single boranophosphate modification at either the α-, β- or γ-position of the 5′,5′-triphosphate chain. The compounds can potentially serve either as inhibitors of translation in cancer cells or reagents for increasing expression of therapeutic proteins in vivo from exogenous mRNAs. The BH3-analogs were tested as substrates and binding partners for two major cytoplasmic cap-binding proteins, DcpS, a decapping pyrophosphatase, and eIF4E, a translation initiation factor. The susceptibility to DcpS was different between BH3-analogs and the corresponding analogs containing S instead of BH3 (S-analogs). Depending on its placement, the boranophosphate group weakened the interaction with DcpS but stabilized the interaction with eIF4E. The first of the properties makes the BH3-analogs more stable and the second, more potent as inhibitors of protein biosynthesis. Protein expression in dendritic cells was 2.2- and 1.7-fold higher for mRNAs capped with m27,2′-OGppBH3pG D1 and m27,2′-OGppBH3pG D2, respectively, than for in vitro transcribed mRNA capped with m27,3′-OGpppG. Higher expression of cancer antigens would make mRNAs containing m27,2′-OGppBH3pG D1 and m27,2′-OGppBH3pG D2 favorable for anticancer immunization. PMID:25150148

  8. Interferon Alpha Signalling and Its Relevance for the Upregulatory Effect of Transporter Proteins Associated with Antigen Processing (TAP) in Patients with Malignant Melanoma

    PubMed Central

    Ensslen, Silke; Marquardt, Yvonne; Czaja, Katharina; Joussen, Sylvia; Beer, Daniel; Abele, Rupert; Plewnia, Gabriele; Tampé, Robert; Merk, Hans F.; Hermanns, Heike M.; Baron, Jens M.

    2016-01-01

    Introduction Interferon alpha (IFNα) is routinely used in the clinical practice for adjuvant systemic melanoma therapy. Understanding the molecular mechanism of IFNα effects and prediction of response in the IFNα therapy regime allows initiation and continuation of IFNα treatment for responder and exclusion of non-responder to avoid therapy inefficacy and side-effects. The transporter protein associated with antigen processing-1 (TAP1) is part of the MHC class I peptide-loading complex, and important for antigen presentation in tumor and antigen presenting cells. In the context of personalized medicine, we address this potential biomarker TAP1 as a target of IFNα signalling. Results We could show that IFNα upregulates TAP1 expression in peripheral blood mononuclear cells (PBMCs) of patients with malignant melanoma receiving adjuvant high-dose immunotherapy. IFNα also induced expression of TAP1 in mouse blood and tumor tissue and suppressed the formation of melanoma metastasis in an in vivo B16 tumor model. Besides its expression, TAP binding affinity and transport activity is induced by IFNα in human monocytic THP1 cells. Furthermore, our data revealed that IFNα clearly activates phosphorylation of STAT1 and STAT3 in THP1 and A375 melanoma cells. Inhibition of Janus kinases abrogates the IFNα-induced TAP1 expression. These results suggest that the JAK/STAT pathway is a crucial mediator for TAP1 expression elicited by IFNα treatment. Conclusion We suppose that silencing of TAP1 expression provides tumor cells with a mechanism to escape cytotoxic T-lymphocyte recognition. The observed benefit of IFNα treatment could be mediated by the shown dual effect of TAP1 upregulation in antigen presenting cells on the one hand, and of TAP1 upregulation in ‘silent’ metastatic melanoma cells on the other hand. In conclusion, this work contributes to a better understanding of the mode of action of IFNα which is essential to identify markers to predict, assess and

  9. Mechanism of Carbonate Assimilation in the Middle Ordovician Hortavær Igneous Complex, north-central Norway

    NASA Astrophysics Data System (ADS)

    Barnes, C.; Li, Y.; Prestvik, T.; Barnes, M. A.

    2008-12-01

    The Hortavær igneous complex consists primarily of mafic to intermediate magmas emplaced as sheets into marble, calc-silicate, semipelitic, and quartzofeldspathic rocks as well as coeval, cogenetic syenitic magmas. Parental mafic magmas have arc-like trace element signatures and were H2O -rich. Carbonate assimilation was a heterogeneous process and the degree of assimilation varied by locality from 0 to 20 wt percent. Trace element and isotopic compositions of magmatic calcite, compositions of grossular-andradite garnet in endoskarns, and field evidence for partial melting of the endoskarns indicate that carbonate assimilation was a multistage process. Initially, H2O -rich fluid from mafic magmas infiltrated calc-silicate xenoliths/screens, resulting in lowering of their solidus. Partial melting of these screens increased their porosity and decreased their strength, leading to disruption and mingling with mafic magmas as well as bringing carbonate-rich melt into contact with the surrounding silicate magmas. This process also permitted infiltration of silicate melt into the partially melted calc-silicate rocks, enhancing development of garnet ferrohedenbergite ± wollastonite melasyenitic endoskarn. Carbonate melt from the xenoliths mixed with the surrounding mafic magmas by reactive assimilation; this process can sensibly be described as reaction of olivine and calcite components in melt phases to form augitic (fassaitic) clinopyroxene (cpx) and CO2. This enhanced stability of cpx is reflected in the presence of cpx-rich cumulates, fractionation of which resulted in alkali enrichment and formation of abundant syenitic magma. During later stages of magma evolution (monzonitic to syenitic and granitic composition), assimilation of quartzofeldspathic to pelitic rocks became dominant, and magma compositions evolved from nepheline- to quartz-normative. The large amount of host rock (carbonate, calc-silicate or pelite) assimilation in the Hortavær complex was enhanced

  10. Influence of Large Igneous Provinces on Svalbard tectonics and sedimentation from the Late Mesozoic through Cenozoic: Insight from (U-Th)/He zircon and apatite thermochronology

    NASA Astrophysics Data System (ADS)

    Barnes, Christopher; Schneider, David; Majka, Jaroslaw

    2016-04-01

    cooling (85-65 Ma), coeval with development of the Late Cretaceous unconformity, is indicative of moderate uplift on Svalbard during this time. We interpret this as rift-flank uplift, related to opening in the Lincoln Sea north of Svalbard. Given the location of the HALIP plume on the southern Alpha Ridge, we suggest that HALIP emplacement contributed to a stress-field facilitating rifting in the Lincoln Sea (a precursor to rifting of the southern Eurasian Basin; c. 56 Ma). A change in paleoflow direction of Svalbard sediments from Paleogene NNE-sourced to Eocene W-sourced sediments denotes a change from HALIP-influenced to NAIP-influenced tectonics and sedimentation on Svalbard. An Eocene heating event (55-40 Ma) is the result of tectonic burial via overthrusting during the Eurekan Orogeny, providing the western sediment source. Eurekan tectonism on Svalbard is the result of the northward movement of the Greenland microplate, a consequence of spreading in the North Atlantic Ocean. The most recent cooling event (40-20 Ma) is primarily attributed to rift-flank uplift resulting from northward propagation of the North Atlantic Ocean and opening of the Fram Strait. Low-temperature (U-Th)/He low-temperature thermochronometry allow us to document shallow crustal processes that, which are linked to Large Igneous Provinces and other mantle dynamics.

  11. Relevance, Derogation and Permission

    NASA Astrophysics Data System (ADS)

    Stolpe, Audun

    We show that a recently developed theory of positive permission based on the notion of derogation is hampered by a triviality result that indicates a problem with the underlying full-meet contraction operation. We suggest a solution that presupposes a particular normal form for codes of norms, adapted from the theory of relevance through propositional letter sharing. We then establish a correspondence between contractions on sets of norms in input/output logic (derogations), and AGM-style contractions on sets of formulae, and use it as a bridge to migrate results on propositional relevance from the latter to the former idiom. Changing the concept accordingly we show that positive permission now incorporates a relevance requirement that wards off triviality.

  12. Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

    USGS Publications Warehouse

    Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

    2006-01-01

    High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

  13. A reflection seismic study of the Alnö alkaline and carbonatite igneous complex

    NASA Astrophysics Data System (ADS)

    Andersson, M.; Malehmir, A.; Dehghannejad, M.; Troll, V. R.; Ask, M.

    2012-04-01

    The Alnö igneous complex in central Sweden is one of the largest (about 5 km by 5 km) of the few well-known alkaline and carbonatite intrusions in the world. It contains a wide variety of lithologies, including alkaline silicate igneous rocks (Ijolite, Nephelinesyenite, and Pyroxenite) and a range of carbonatite dykes with a variable composition (Kresten, 1990). Alnö island is the type locality for Alnöite, a melilite-bearing basic rock that occurs as dykes and contains a complex mineral assemblage with phenocrysts from the deep crust and the upper mantle. Geochronological measurements suggest an age of 553-590 Ma for the main intrusion. The depth extent, dip and dip direction of the carbonatite rocks have been inferred from surface geological mapping, but lack depth-constraints. Our research aims to improve understanding of the intrusion mechanism(s) and the geometry of the Alnö intrusion and through that of alkaline and carbonatite intrusions in general. We have acquired three high-resolution reflection seismic profiles over the main intrusion during winter 2011. Densely sampled surface gravity and magnetic data were also collected along the seismic profiles and on the sea-ice with gravity measurements indicating a strong positive Bouguer anomaly of about 20 mGal over the main intrusion. Petrophysical measurements including compressional- and shear-wave velocities, anisotropy of magnetic susceptibility (AMS), and density data were gathered from oriented samples of representative lithologies. For the seismic data, nearly 400 active channels were employed with a geophone spacing of 10 meters. A mechanical hammer was used for generating the seismic waves and was activated at most geophone positions. Since the acquisition took part in winter, we also extended the profiles out on the sea-ice close to the shore. The geophones were planted in the frozen ground/ice and covered by snow resulting in improved signal-to-noise ratios. The main profile is about 10 km long

  14. Ferropicrite from the Lalibela area in the Ethiopian large igneous province

    NASA Astrophysics Data System (ADS)

    Desta, M. T.; Ishiwatari, A.; Arai, S.; Akihiro, T.; Ayalew, D.

    2013-12-01

    Ferropicrite and picritic ferrobasalt lava flows near Lalibela in the Oligocene (~ 30 Ma) Ethiopian large igneous provence (LIP) are associated with ultratitaniferous transitional basalt and picrites of the second high-Ti (HT2) series. The dominant phenocryst in the studied samples is Mg-rich olivine (up to Mg# 88.4) with high CaO contents (to 0.42 wt. %) and kink band structure is absent, indicating that olivines are crystalized from a melt. Spinel inclusions and microphenocrysts are characterized by extremely high Cr# (79-84), moderate Mg# (18-51), moderate Fe3+# (11-26) and contains 3.6-14.8 wt. % TiO2. The clinopyroxene phenocrysts are Mg#=73-88, TiO2=0.84-2.9 wt. %, and Al2O3= 1.2-4.1 wt. % in the cores. The REE contents of clinopyroxenes display enrichment in LREE (LaN/YbN=1.2-1.9) and MREE (EuN/YbN=3.3-4.3) relative to HREE. Relative depletion of HFSE (e.g. Nb and Zr) is also observed. In general, these trace element characteristics of clinopyroxene are similar with those of high-Ti 2 basalts. The estimated MgO content of liquid is about 23.5 wt. % and mantle potential temperature may have been as high as ~ 1638 OC. This temperature (Tp) is higher (by some 100 OC) than those estimated for the African-Arabian traps (~ 1520 OC). The studied samples exhibit very low Al2O3/TiO2 (1.8-2.2) and high Zr/Y (8.2-10.2) ratios. These may indicate the important role for garnet during melting and that the lavas were formed by small degree of partial melting which apparently contradicts to the high Cr# of spinel. In view of low Cr/Al ratio of the bulk rock, the high Cr# of spinel suggests very high temperature of the magma (and the plume). The origin of these ferropicrite and picritic ferrobasalt rocks could be attributed to high pressure partial melting of pyroxenite that possibly incorporate recycled oceanic crust components. Keywords: Ferropicrite, large igneous province, Oligocene, pyroxinite, Lalibela

  15. Postcollisional mafic igneous rocks record recycling of noble gases by deep subduction of the continental crust

    NASA Astrophysics Data System (ADS)

    Dai, Li-Qun; Zheng, Yong-Fei; He, Huai-Yu; Zhao, Zi-Fu

    2016-05-01

    Recycling of noble gases from crustal rocks into the mantle is indicated not only by oceanic basalts and mantle xenoliths, but also by ultrahigh-pressure metamorphic rocks in collisional orogens. It is intriguing whether noble gases in continental crust were recycled into the mantle by deep subduction of the continental crust to mantle depths. Here we firstly report the He, Ne and Ar isotopic compositions of pyroxene from postcollisional mafic igneous rocks in the Dabie orogen, China. The results show that the pyroxene separates from the mafic rocks have low 3He/4He ratios of 0.002 to 1.8 Ra and air-like Ne isotope compositions. Furthermore, the pyroxene exhibits low 40Ar/36Ar ratios of 393.6 to 1599.8, close to those of the air. In combination with whole-rock geochemistry it is found that pyroxene 3He/4He ratios are correlated with whole-rock (La/Yb)N and Sr/Y ratios, εNd(t) values and MgO contents. These observations demonstrate the mass transfer from the deeply subducted continental crust to the overlying mantle wedge, recording the source mixing between the crust-derived melt and the mantle peridotite in the continental subduction zone. A direct addition of the crustal He via crust-derived melt to the mantle leads to the extremely low 3He/4He ratios in the orogenic lithospheric mantle, and the dissolved atmospheric Ar and Ne in the subducted supracrustal rocks results in the air-like Ar and Ne isotope ratios. Therefore, the noble gas isotopic signatures of supracrustal rocks were carried into the mantle by the continental deep subduction to subarc depths and then transferred to the postcollisional mafic igneous rocks via the melt-peridotite reaction at the slab-mantle interface in a continental subduction channel. Our finding firstly establishes the slab-mantle interaction model for recycling of supracrustal noble gases in the continental subduction zone.

  16. Distinct Igneous APXS Rock Compositions on Mars from Pathfinder, MER and MSL

    NASA Technical Reports Server (NTRS)

    Gellert, Ralf; Arvidson, Raymond; Clark, Benton, III; Ming, Douglas W.; Morris, Richard V.; Squyres, Steven W.; Yen, Albert S.

    2015-01-01

    The alpha particle x-ray spectrometer (APXS) on all four Mars Rovers returned geochemical data from about 1000 rocks and soils along the combined traverses of over 50 kilometers. Here we discuss rocks likely of igneous origin, which might represent source materials for the soils and sediments identified along the traverses. Adirondack-type basalts, abundant in the plains of Gusev Crater, are primitive, olivine bearing basalts. They resemble in composition the basaltic soils encountered at all landing sites, except the ubiquitous elevated S, Cl and Zn in soils. They have been postulated to represent closely the average Martian crust composition. The recently identified new Martian meteorite Black Beauty has similar overall geochemical composition, very distinct from the earlier established SNC meteorites. The rim of the Noachian crater Endeavour, predating the sulfate-bearing Burns formation at Meridiani Planum, also resembles closely the composition of Adirondack basalts. At Gale Crater, the MSL Curiosity rover identified a felsic rock type exemplified by the mugearitic float rock JakeM, which is widespread along the traverse at Gale. While a surprise at that time, possibly related more evolved, alkaline rocks had been previously identified on Mars. Spirit encountered the Wishstone rocks in the Columbia Hills with approx. 6% Na2O+K2O, 15 % Al2O3 and low 12% FeO. Pathfinder rocks with elevated K and Na and >50% SiO2 were postulated to be andesitic. Recently Opportunity encountered the rock JeanBaptisteCharbonneau with >15% Al2O3, >50% SiO2 and approx. 10% FeO. A common characteristic all these rocks is the very low abundance of Cr, Ni and Zn, and an Fe/Mn ratio of about 50, indicating an unaltered Fe mineralogy. Beside these likely igneous rock types, which occurred always in several rocks, a few unique rocks were encountered, e.g. Bounce Rock, a pyroxene-bearing ejecta rock fragment resembling the Shergottite EETA 79001B meteorite. The APXS data can be used to

  17. Subsurface Structure of the Bushveld Igneous Complex, South Africa: An Application of Geophysics

    NASA Astrophysics Data System (ADS)

    Vallejo, G.; Galindo, B. L.; Carranza, V.; Gomez, C. D.; Ortiz, K.; Castro, J. G.; Falzone, C.; Guandique, J.; Emry, E.; Webb, S. J.; Nyblade, A.

    2014-12-01

    South Africa is host to the largest single known platinum group metal supply in the world. The Bushveld Igneous Complex, spanning 300x400 kilometers, hosts hundreds of years' worth of platinum, chromite, vanadium, and other ore. Its wealth of these metals is tied directly to the large layered igneous intrusion that formed roughly 2061 million years ago. The extraction of platinum is vital to the industrial world - as these metals are widely used in the automotive industry, dental restorations, computer technology, in addition to many other applications. In collaboration with the Africa Array geophysics field school and the Penn State Summer Research Opportunities Program (SROP), we surveyed the Modikwa mine located along the border of the provinces of Mpumalanga and Limpopo in South Africa. The following techniques were applied to survey the area of interest: seismic refraction and reflection, gravity, magnetics, electrical resistivity, and electromagnetics. The data collected were used to determine the depth to bedrock and to identify potential mining hazards from dykes and faults in the bedrock. Several areas were studied and with the combination of the above-mentioned methods several possible hazards were identified. One broad, major dyke that was located in a prior aeromagnetic survey and several previously undetected, parallel, minor dykes were identified in the region. The overburden thickness was determined to be ̴4-5 meters in some regions, and as thin as several centimeters in others. This section of rock and soil lies above an area where platinum will likely be mined in the future. The removal of overburden can be accomplished by using power shovels or scrapers; while remaining material can be contained with the use of galvanized steel culverts. Additionally, a number of joints were located that may have allowed water to accumulate underground. The models created from the data permit us to estimate which hazards could be present in different parts of the

  18. Blending Rigor and Relevance

    ERIC Educational Resources Information Center

    Siri, Diane K.; Zinner, Jane; Lezin, Nicole

    2011-01-01

    A collaborative at several sites across the state of California will offer evidence of how successful linked learning, which connects academics to real-world work, can be. This article presents examples that illustrate the powerful connections and linkages that are generated by combining academic rigor with the relevance of applying learning to…

  19. Is Information Still Relevant?

    ERIC Educational Resources Information Center

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  20. The Relevance of Literature.

    ERIC Educational Resources Information Center

    Dunham, L. L.

    1971-01-01

    The "legacy" of the humanities is discussed in terms of relevance, involvement, and other philosophical considerations. Reasons for studying foreign literature in language classes are developed in the article. Comment is also made on attitudes and ideas culled from the writings of Clifton Fadiman, Jean Paul Sartre, and James Baldwin. (RL)

  1. Reading, Writing and Relevance.

    ERIC Educational Resources Information Center

    Hoffman, Mary

    This monograph presents classroom activities that were designed to encourage children to read and write in a self-reliant and responsible manner. The activities were chosen for their relevance to the children involved and because the vocabulary involved was interesting, familiar, and worth remembering and using again. The topics are arranged in…

  2. The impact of igneous bedrock weathering on the Mo isotopic composition of stream waters: Natural samples and laboratory experiments

    NASA Astrophysics Data System (ADS)

    Voegelin, Andrea R.; Nägler, Thomas F.; Pettke, Thomas; Neubert, Nadja; Steinmann, Marc; Pourret, Olivier; Villa, Igor M.

    2012-06-01

    River waters have been shown to be systematically enriched in the heavy molybdenum (Mo) isotopes when compared to typical granites and basalts, which generally possess Mo isotopic compositions (δMo) of around 0‰. This inconsistency has been used to argue against weathering of crustal rocks as the cause for heavy riverine δMo signatures. Incongruent dissolution of primary bedrock, however, may be an important process by which the anomalous Mo signatures of the river dissolved load are produced. This study therefore investigates the effect of igneous crustal rock weathering on the aquatic δMo signal by comparing stream water and bedrock Mo isotope data to results of bulk rock leach experiments. For this purpose, stream water and bedrock (orthogneiss, granite, basalt), as well as soil and vegetation samples were collected in a small catchment in the French Massif Central. In accordance with the results of earlier studies on riverine Mo, both streams are isotopically heavier (δMo = 0.5-1.1‰) than the typical granites and basalts. The excellent agreement of these data with those of Mo released during experimental leaching of the basalt bedrock (0.6-1.0‰) identifies a predominance of basalt weathering over the stream water Mo geochemistry, while other processes (i.e. soil formation, secondary mineral precipitation and adsorption) are subordinate in this catchment. Given that the basalt bulk rock δMo reflects a value typical for crustal magmatic rocks (ca. 0.1‰), Mo isotope fractionation during the incongruent dissolution of basalt can explain the observed isotopically heavy aquatic Mo signatures. Laser ablation analyses demonstrate that the volumetrically minor magmatic sulfides can be highly enriched in Mo and mass balance calculations identify the sulfide melt inclusions as the principal Mo source for the leach solutions. These data suggest that the magmatic sulfides possess a distinctly heavier δMo signature than the coexisting silicate melt. In this

  3. Radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico with annotated bibliography. [Over 600 citations

    SciTech Connect

    McLemore, V. T.

    1982-01-01

    From an extensive literature search and field examination of 96 nonsandstone radioactive occurrences, the author compiled an annotated bibliography of over 600 citations and a list of 327 radioactive occurrences in veins and igneous and metamorphic rocks of New Mexico. The citations are indexed by individual radioactive occurrence, geographic area, county, fluorspar deposits and occurrences, geochemical analyses, and geologic maps. In addition, the geology, mineralization, and uranium and thorium potential of 41 geographic areas in New Mexico containing known radioactive occurrences in veins and igneous and metamorphic rocks or that contain host rocks considered favorable for uranium or thorium mineralization are summarized. A list of aerial-radiometric, magnetic, hydrogeochemical, and stream-sediment survey reports is included.

  4. Thermal infrared (2.5-13.5-micron) spectroscopic remote sensing of igneous rock types on particulate planetary surfaces

    NASA Technical Reports Server (NTRS)

    Salisbury, John W.; Walter, Louis S.

    1989-01-01

    The compositional significance of outstanding spectral features in the reflectance spectra of particulate igneous rocks was investigated by analyzing directional reflectance spectra, obtained with an FTIR spectrophotometer at 2.17-13.5 microns, of a suite of well-characterized igneous rocks ground to fine particle size. It was found that, using spectral features associated with the principal Christiansen frequency and with a region of relative transparency between the Si-O stretching and bending bands, it is possible to identify general rock type using the Walter and Salisbury (1989) SCFM chemical index, SCFM, defined as SCFM = SiO2/(SiO2 + CaO + FeO + MgO). It is emphasized, however, that the appearance and the wavelength of these features may be affected by environmental factors.

  5. Late neoproterozoic igneous complexes of the western Baikal-Muya Belt: Formation stages

    NASA Astrophysics Data System (ADS)

    Fedotova, A. A.; Razumovskiy, A. A.; Khain, E. V.; Anosova, M. O.; Orlova, A. V.

    2014-07-01

    The paper presents new geological, geochemical, and isotopic data on igneous rocks from a thoroughly studied area in the western Baikal-Muya Belt, which is a representative segment of the Neoproterozoic framework of the Siberian Craton. Three rock associations are distinguished in the studied area: granulite-enderbite-charnockite and ultramafic-mafic complexes followed by the latest tonalite-plagiogranitegranite series corresponding to adakite in geochemical characteristics. Tonalites and granites intrude the metamorphic and gabbroic rocks of the Tonky Mys Point, as well as Slyudyanka and Kurlinka intrusions. The tonalites yielded a U-Pb zircon age of 595 ± 5 Ma. The geochronological and geological information indicate that no later than a few tens of Ma after granulite formation they were transferred to the upper lithosphere level. The Sm-Nd isotopic data show that juvenile material occurs in rocks of granitoid series (ɛNd(t) = 3.2-7.1). Ophiolites, island-arc series, eclogites, and molasse sequences have been reviewed as indicators of Neoproterozoic geodynamic settings that existed in the Baikal-Muya Belt. The implications of spatially associated granulites and ultramafic-mafic intrusions, as well as granitoids with adakitic geochemical characteristics for paleogeodynamic reconstructions of the western Baikal-Muya Belt, are discussed together with other structural elements of the Central Asian Belt adjoining the Siberian Platform in the south.

  6. Evaluation of and new completion recommendations for a fractured, crystalline, igneous reservoir, Texas Panhandle

    SciTech Connect

    Weimer, B.A.; Manwaring, M.S. )

    1987-02-01

    In the Panhandle field of Texas, the lowest stratigraphic producing formation is a crystalline basement rock. The igneous rock is productive when it is naturally fractured sufficiently to hold hydrocarbons trapped in the same structure as the expansive Panhandle field. Research work to understand the crystalline reservoir better focused on the fracturing, mineralogy, and production potential of the basement interval. This trap is a true fractured reservoir; it has no more than 1% primary porosity in the nonfractured rock. The mineralogy of the host rock and fracture-filling minerals was established from drill and core samples. The host rock is a complex of granodiorite, dacite, and gabbroic diorite. Scanning electron microscopy, x-ray diffraction, and optical work confirmed the occurrence of at least 12 secondary fracture-fill minerals. Fluid inclusion analysis established formation temperatures for many of the minerals and allowed postulation of a detailed sequence of formation. The character of the fracture in differing host petrologies and the occurrence of clay minerals coating fracture surfaces were deemed to be critical factors in hydrocarbon production. New and specific enhancement treatments were designed for the subject reservoir, and these recommendations were used in a test well. Results from the test were favorable and appear to confirm the ideas formed from this work. The new recommended treatments are less expensive than current practices and indicate potential for greater ultimate recoveries of oil.

  7. The Mozambique Ridge - A Large Igneous Province with a Complicated Emplacement History

    NASA Astrophysics Data System (ADS)

    Fischer, M. D.; Uenzelmann-Neben, G.

    2015-12-01

    The Mozambique Ridge (MozR), a supposed part of the South African Large Igneous Province (LIP) in the southwestern Indian Ocean, consists of four major geomorphological units associated with multiple phases of volcanic activity between 140 Ma and 120 Ma. High-resolution seismic reflection data collected in 2014 reveals various magmatic centres within each of the geomorphological units. Intra-basement reflections can be identified up to several hundred ms TWT below top of basement. These are interpreted to represent massive lava flow units, which are characteristic of oceanic plateau eruptions. Additionally to primary volcanic features associated with the initial formation of the different segments of the MozR we identify secondary volcanic features indicating magmatic reactivation after its initial build-up. The internal reflections generally dip away from their magmatic centres and individual reflectors are typically traced for 5-15 km. Several faults cutting through basement and older sedimentary units are interpreted as extensional tectonic features.Our observations hence provide further arguments for a LIP origin of the MozR. Still, this LIP obviously was subject to multiple magmatic and tectonic phases during its development, which we may relate with the opening of the South African gateway associated with Gondwana break-up and the separation of MozR from the conjugate parts of the proposed South African LIP. Further investigations will show whether more recent deformation can be traced back to further propagation of the East African Rift system.

  8. Zonation of the Newry Igneous Complex, Northern Ireland, based on geochemical and geophysical data

    NASA Astrophysics Data System (ADS)

    Anderson, P. E.; Cooper, M. R.; Stevenson, C. T.; Hastie, A. R.; Hoggett, M.; Inman, J.; Meighan, I. G.; Hurley, C.; Reavy, R. J.; Ellam, R. M.

    2016-09-01

    The Late Caledonian Newry Igneous Complex (NIC), Northern Ireland, comprises three largely granodioritic plutons, together with an intermediate-ultramafic body at its northeastern end. New whole-rock geochemical data, petrological classifications, and published data, including recent Tellus aeromagnetic and radiometric results, have been used to establish 15 distinct zones across the four bodies of the NIC. These become broadly younger to the southwest of the complex and toward the centres of individual plutons. In places, zones are defined by both current compositional data (geochemistry and petrology) and Tellus results. This is particularly clear at the eastern edge of the NIC, where a thorium-elevated airborne radiometric signature occurs alongside distinct concentrations of various elements from geochemistry. However, in the northeastern-most pluton of the NIC, a prominent ring-shaped aeromagnetic anomaly occurs independent of any observed surface compositional variation, and thus the zones in this area are defined by aeromagnetic data only. The origins of this and other aeromagnetic anomalies are as yet undetermined, although in places, these closely correspond to facies at the surface. The derived zonation for the NIC supports incremental emplacement of the complex as separate, distinct magma pulses. Each pulse is thought to have originated from the same fractionally crystallising source that periodically underwent mixing with more basic magma.

  9. Spectral characterization of igneous rocks in the 8- to 12-micron region

    NASA Technical Reports Server (NTRS)

    Walter, Louis S.; Salisbury, John W.

    1989-01-01

    This paper investigates the crystal-chemistry basis for the variation in spectral behavior of ingneous rocks, with the purpose of developing relationships useful for applications in the lithologic characterization of terrestrial and extraterrestrial surfaces. A new parameter is proposed for characterizing general rock and mineral type. The parameter, SCFM, defined as the ratio SiO2/(SiO2 + CaO + FeO + MgO), reflects the degree of depolymerization of the silica tetrahedra in both fine-grained and coarse-grained igneous rocks, and is a good descriptor of the composition of these rocks. Using spectra obtained in the laboratory on coarse-particulate mineral and solid-rock samples, the SCFM parameter was used to assess the effects of variations in the rock composition on the location, number, and width of spectral bands. A regression analysis of bands varying in width from 0.2 micron to 1.4 microns versus the SCFM value resulted in correlation coefficients ranging from 0.88 to 0.97.

  10. Methane release from igneous intrusion of coal during Late Permian extinction events

    SciTech Connect

    Retallack, G.J.; Jahren, A.H.

    2008-01-15

    Unusually large and locally variable carbon isotope excursions coincident with mass extinctions at the end of the Permian Period (253 Ma) and Guadalupian Epoch (260 Ma) can be attributed to methane outbursts to the atmosphere. Methane has isotopic values {delta}{sup 13}C low enough to reduce to feasible amounts the carbon required for isotopic mass balance. The duration of the carbon isotopic excursions and inferred methane releases are here constrained to < 10,000 yr by counting annual varves in lake deposits and by estimating peat accumulation rates. On paleogeographic maps, the most marked carbon isotope excursions form linear arrays back to plausible methane sources: end-Permian Siberian Traps and Longwood-Bluff intrusions of New Zealand and end-Guadalupian Emeishan Traps of China. Intrusion of coal seams by feeder dikes to flood basalts could create successive thermogenic methane outbursts of the observed timing and magnitude, but these are unreasonably short times for replenishment of marine or permafrost sources of methane. Methane released by fracturing and heating of coal during intrusion of large igneous provinces may have been a planetary hazard comparable with bolide impact.

  11. U-Pb zircon geochronology and evolution of some Adirondack meta-igneous rocks

    NASA Technical Reports Server (NTRS)

    Mclelland, J. M.

    1988-01-01

    An update was presented of the recent U-Pb isotope geochronology and models for evolution of some of the meta-igneous rocks of the Adirondacks, New York. Uranium-lead zircon data from charnockites and mangerites and on baddeleyite from anorthosite suggest that the emplacement of these rocks into a stable crust took place in the range 1160 to 1130 Ma. Granulite facies metamorphism was approximately 1050 Ma as indicated by metamorphic zircon and sphene ages of the anorthosite and by development of magmatitic alaskitic gneiss. The concentric isotherms that are observed in this area are due to later doming. However, an older contact metamorphic aureole associated with anorthosite intrusion is observed where wollastonite develops in metacarbonates. Zenoliths found in the anorthosite indicate a metamorphic event prior to anorthosite emplacement. The most probable mechanism for anorthosite genesis is thought to be ponding of gabbroic magmas at the Moho. The emplacement of the anorogenic anorthosite-mangerite-charnockite suite was apparently bracketed by compressional orogenies.

  12. Rock property measurements and analysis of selected igneous, sedimentary, and metamorphic rocks from worldwide localities

    USGS Publications Warehouse

    Johnson, Gordon R.

    1983-01-01

    Dry bulk density and grain density measurements were made on 182 samples of igneous, sedimentary, and metamorphic rocks from various world-wide localities. Total porosity values and both water-accessible and helium-accessible porosities were calculated from the density data. Magnetic susceptibility measurements were made on the solid samples and permeability and streaming potentials were concurrently measured on most samples. Dry bulk densities obtained using two methods of volume determination, namely direct measurement and Archlmedes principle, were nearly equivalent for most samples. Grain densities obtained on powdered samples were typically greater than grain densities obtained on solid samples, but differences were usually small. Sedimentary rocks had the highest percentage of occluded porosity per rock volume whereas metamorphic rocks had the highest percentage of occluded porosity per total porosity. There was no apparent direct relationship between permeability and streaming potential for most samples, although there were indications of such a relationship in the rock group consisting of granites, aplites, and syenites. Most rock types or groups of similar rock types of low permeability had, when averaged, comparable levels of streaming potential per unit of permeability. Three calcite samples had negative streaming potentials.

  13. Paleozoic large igneous provinces of Northern Eurasia: Correlation with mass extinction events

    NASA Astrophysics Data System (ADS)

    Kravchinsky, Vadim A.

    2012-04-01

    This paper assesses data from recently described major Paleozoic large igneous provinces (LIPs), mostly in Northern Eurasia. The 10 LIPs reviewed form a unimodal distribution in terms of volume. Eight LIPs have an initial modal volume greater than 0.1 × 106 km3. The rift associated basalts of 2 LIPs from the end of the Late Cambrian Period and the end of the Late Ordovician Period do not occupy a large volume. Some of the provinces were discovered or rediscovered relatively recently and dating is still approximate, but most provinces fit a simple model in which volcanism persisted on the order of 10-20 Myr, often resulting in continental break-up. Correlation between LIP ages and the ages of geological events in the Paleozoic Era that reflect mass extinctions and oceanic anoxia agrees with correlations suggested by Courtillot (1994) and Courtillot and Renne (2003) for the Cenozoic and Mesozoic eras, considering that the absolute dating of some Paleozoic LIPs needs to be strengthened in the future.

  14. Igneous cooling history of olivine-phyric shergottite Yamato 980459 constrained by dynamic crystallization experiments

    NASA Astrophysics Data System (ADS)

    First, Emily; Hammer, Julia

    2016-05-01

    Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine-phyric shergottite Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h-1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h-1, consistent with crystallization within a lava flow at depths of 25-45 cm. Increased cooling rate (~100 °C h-1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5-7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe-like flow and subsequent breakout on the surface of Mars.

  15. Shallow drilling investigation of contact relationships in the Wichita Mountains igneous province

    SciTech Connect

    Gilbert, M.C.; Hogan, J.P. . School of Geology and Geophysics); Luza, K. )

    1993-02-01

    Within the Wichita Mountains Igneous Province, a variety of mineralogically, texturally and compositionally diverse hybrid rock types (i.e. gabbro-diorites, monzonites and granodiorites) crop out at gabbro-grants contacts. Possible coeval sedimentary rocks associated with crustal rifting are restricted to a few scattered, isolated exposures of a mineralogically variable group of meta-quartzites (Meers Quartzite). Typically these outcrops of meta-quartzite are of limited areal extent and are surrounded by either gabbro, granite, rhyolite or a combination of these rock types. However, the origin of both the hybrid rock types and the Meers Quartzite remains enigmatic because outcrops containing complete and clear contact relationships are extremely rare. At present, direct testing of models is difficult as complete exposure of contacts between these units is extremely rare due to deposition of younger sedimentary units and severe degradation by weathering. Poor condition of existing samples has hampered geochemical and other petrologic methods in evaluating models. Four potential drilling sites have been selected where critical contacts between major geologic units are interpreted to be present in the shallow subsurface (<300 ft.). Objectives of drilling are (1) direct observation of contacts between rock units by retrieval of a complete core sample from the drill hole, (2) retrieval of freshest possible rock material for petrographic and geochemical analysis and (3) retrieval of a complete transect beginning in Mount Scott Granite or Meers Quartzite across the hybrid rock zone and into the substrate gabbro to document variations associated with the transition.

  16. Thermal aureoles of igneous intrusions: some possible indications of hydrothermal convective cooling

    SciTech Connect

    Parmentier, E.M.; Schedl, A.

    1981-01-01

    The size and shape of metamorphic aureoles is investigated as a possible indicator of hydrothermal convective cooling of epizonal igneous intrusions. A simple family of numerical models illustrates the effect of convective cooling on maximum temperatures attained in the country rock surrounding an intrusion. Boundary layer approximations have also been applied to describe convection of vaporizing groundwater near the contact of an intrusion early in its cooling history. Maximum temperature isotherms are taken to reflect the width and shape of thermal aureoles defined by preserved mineral assemblages as appears to be reasonable based on several well-studied conductively cooled intrusions. The thermal aureoles of intrusions for which oxygen and hydrogen isotope data indicate convective groundwater circulation have been examined on the basis of the simple numerical and boundary layer models. The shape of the low temperature alteration aureole of the well-mapped El Salvador porphyry copper deposit suggests convective cooling of a permeable intrusion. The width of the low temperature (greenschist) aureole of the Mull intrusive complex can be explained by convective cooling of permeable intrusive rock. The narrow high temperature (amphibolite) aureole of the Cuillin gabbro on Skye can be explained by strong convective cooling; but the low temperature (greenschist) aureole is wide enough to be consistent with conductive cooling, thus suggesting decreasing permeabilities during the cooling history. This is consistent with oxygen isotope sampling and other geologic observations.

  17. U-Pb zircon geochronology and evolution of some Adirondack meta-igneous rocks

    NASA Astrophysics Data System (ADS)

    McLelland, J. M.

    An update was presented of the recent U-Pb isotope geochronology and models for evolution of some of the meta-igneous rocks of the Adirondacks, New York. Uranium-lead zircon data from charnockites and mangerites and on baddeleyite from anorthosite suggest that the emplacement of these rocks into a stable crust took place in the range 1160 to 1130 Ma. Granulite facies metamorphism was approximately 1050 Ma as indicated by metamorphic zircon and sphene ages of the anorthosite and by development of magmatitic alaskitic gneiss. The concentric isotherms that are observed in this area are due to later doming. However, an older contact metamorphic aureole associated with anorthosite intrusion is observed where wollastonite develops in metacarbonates. Zenoliths found in the anorthosite indicate a metamorphic event prior to anorthosite emplacement. The most probable mechanism for anorthosite genesis is thought to be ponding of gabbroic magmas at the Moho. The emplacement of the anorogenic anorthosite-mangerite-charnockite suite was apparently bracketed by compressional orogenies.

  18. Igneous cooling history of olivine-phyric shergottite Yamato 980459 constrained by dynamic crystallization experiments

    NASA Astrophysics Data System (ADS)

    First, Emily; Hammer, Julia

    2016-07-01

    Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine-phyric shergottite Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h-1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h-1, consistent with crystallization within a lava flow at depths of 25-45 cm. Increased cooling rate (~100 °C h-1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5-7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe-like flow and subsequent breakout on the surface of Mars.

  19. Ages and petrogenetic significance of igneous mangerite-charnockite suites associated with massif anorthosites, Grenville Province

    SciTech Connect

    Emslie, R.F.; Hunt, P.A. )

    1990-03-01

    U-Pb ages of zircon fractions of major anorthosite-mangerite-charnockite-granite (AMCG) igneous suites imply that this magmatism inaugurated what is widely regarded as the Grenvillian event between about 1.16 and 1.12 Ga ago over about two-thirds of the Grenville Province east, northeast, and southeast of the Central Metasedimentary Belt. Pre-Grenvillian AMCG suites about 1.36 and 1.64 Ga old have much more restricted distribution. An apparent time lag of about 0.05 to 0.10 Ga is indicated between culmination of AMCG magmatism and the widely recognized Grenvillian metamorphic peak (about 1.10 to 1.03 Ga), perhaps the most distinctive hallmark of the Grenville event. The time lag is consistent with conductive heating of thick subcontinental lithosphere that began with initiation of AMCG magmatism and continued until geotherms rose sufficiently to produce granulites in much of the lower to middle crust. Tectonic crustal thickening did not likely occur until later in the sequence of events, perhaps after some cooling from the metamorphic peak. Compressive forces were externally applied, possibly at a distant plate margin, while the continental lithosphere was still thermally weakened from preceding magmatic-metamorphic culminations.

  20. Contrasting methods of fracture trend characterization in crystalline metamorphic and igneous rocks of the Windham quadrangle, New Hampshire

    USGS Publications Warehouse

    Walsh, G.J.; Clark, S.F., Jr.

    2000-01-01

    The bedrock of the Windham quadrangle in southeastern New Hampshire consists of deformed early Palaeozoic crystalline metamorphic and intrusive igneous rocks intruded by Mesozoic igneous dikes. Generally, less common northeast striking, steeply dipping fractures developed sub-parallel to the pre-existing tectonic foliation in the Palaeozoic rocks. Mesozoic lamprophyre and diabase dikes intruded along the northeast trending fractures, utilizing the pre-existing anisotropy in the crystalline rocks. Northwest striking, steeply dipping systematic joints and joint sets are the most prominent fractures in the area and, at least in part, post-date the Mesozoic dikes. Sub-horizontal sheeting joints occur in all rock types. Locally, the coincidence of the sub-horizontal fractures with a sub-horizontal Paleozoic cleavage suggests that some of the sheeting fractures utilized the pre-existing ductile anisotropy during unloading. Generally, the metasedimentary rocks show a less complex pattern of fracturing than the intrusive rocks suggesting that rock type is a controlling factor. Metasedimentary rocks in the biotite zone and well-foliated igneous rocks show a greater tendency to fracture along pre-existing bedding and foliation surfaces than metasedimentary rocks in the garnet zone and poorly foliated igneous rocks. A comparison of mapped fracture data and station fracture data indicates that either mapped data or station data can be used to identify regional fracture trends. Local fracture trends can not be identified by limited measurements at a few fracture stations, however, because they do not address spatial variability. Some fracture trends may be scale-dependant because they may be either unique to a local area or present only at regional scales.

  1. PHASS99: A software program for retrieving and decoding the radiometric ages of igneous rocks from the international database IGBADAT

    NASA Astrophysics Data System (ADS)

    Al-Mishwat, Ali T.

    2016-05-01

    PHASS99 is a FORTRAN program designed to retrieve and decode radiometric and other physical age information of igneous rocks contained in the international database IGBADAT (Igneous Base Data File). In the database, ages are stored in a proprietary format using mnemonic representations. The program can handle up to 99 ages in an igneous rock specimen and caters to forty radiometric age systems. The radiometric age alphanumeric strings assigned to each specimen description in the database consist of four components: the numeric age and its exponential modifier, a four-character mnemonic method identification, a two-character mnemonic name of analysed material, and the reference number in the rock group bibliography vector. For each specimen, the program searches for radiometric age strings, extracts them, parses them, decodes the different age components, and converts them to high-level English equivalents. IGBADAT and similarly-structured files are used for input. The output includes three files: a flat raw ASCII text file containing retrieved radiometric age information, a generic spreadsheet-compatible file for data import to spreadsheets, and an error file. PHASS99 builds on the old program TSTPHA (Test Physical Age) decoder program and expands greatly its capabilities. PHASS99 is simple, user friendly, fast, efficient, and does not require users to have knowledge of programing.

  2. In situ enrichment of ocean crust microbes on igneous minerals and glasses using an osmotic flow-through device

    NASA Astrophysics Data System (ADS)

    Smith, Amy; Popa, Radu; Fisk, Martin; Nielsen, Mark; Wheat, C. Geoffrey; Jannasch, Hans W.; Fisher, Andrew T.; Becker, Keir; Sievert, Stefan M.; Flores, Gilberto

    2011-06-01

    The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long-term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbial colonization preferences for 12 minerals and glasses present in igneous rocks. Following recovery of the colonization systems, we measured cell density on the minerals and glasses by fluorescent staining and direct counting and found some significant differences between mineral samples. We also determined the abundance of mesophilic and thermophilic culturable organotrophs grown on marine R2A medium and identified isolates by partial 16S or 18S rDNA sequencing. We found that nine distinct phylotypes of culturable mesophilic oligotrophs were present on the minerals and glasses and that eight of the nine can reduce nitrate and oxidize iron. Fe(II)-rich olivine minerals had the highest density of total countable cells and culturable organotrophic mesophiles, as well as the only culturable organotrophic thermophiles. These results suggest that olivine (a common igneous mineral) in seawater-recharged ocean crust is capable of supporting microbial communities, that iron oxidation and nitrate reduction may be important physiological characteristics of ocean crust microbes, and that heterogeneously distributed minerals in marine igneous rocks likely influence the distribution of microbial communities in the ocean crust.

  3. Microdosing: Concept, Application and Relevance

    PubMed Central

    Tewari, Tushar; Mukherjee, Shoibal

    2010-01-01

    The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country's aspirations to be among the leaders in pharmaceutical research. PMID:21829784

  4. Zircon chemistry and magma mixing, SE China: In-situ analysis of Hf isotopes, Tonglu and Pingtan igneous complexes

    NASA Astrophysics Data System (ADS)

    Griffin, W. L.; Wang, Xiang; Jackson, S. E.; Pearson, N. J.; O'Reilly, Suzanne Y.; Xu, Xisheng; Zhou, Xinmin

    2002-04-01

    Field relations and whole-rock geochemistry indicate that magma mixing has been important in the genesis of the late Mesozoic I-type igneous complexes at Pingtan and Tonglu in SE China. Morphological and trace-element studies of zircon populations in rocks from each of these complexes have defined several distinct growth stages [Mineral. Mag. (2001)]. In-situ LAM-MC-ICPMS microanalysis shows large variations in 176Hf/ 177Hf (up to 15 ɛHf units) between zircons of different growth stages within a single rock, and between zones within single zircon grains (up to 9 ɛHf units). These variations suggest that each of the observed magmas in both complexes developed through hybridisation of ≥2 magmas with different sources. Although this mixing has produced similar Sr and Nd isotopic compositions in the different rock types of each complex, the zircons have functioned as "tape recorders" and have preserved details of the assembly of the different magmas. In the Tonglu complex the most primitive magma is a mafic monzonite (preserved as enclaves), whose isotopic composition suggests derivation from the lower crust; rhyodacites, rhyolites and quartz diorites reflect the mixing of the monzonite with ≥2 more felsic magmas, derived from older crustal materials. In the Pingtan complex, zircons in a quartz diorite enclave suggest mixing between a crustal magma and a more primitive mantle-derived component. Zircons from granites and granodiorite enclaves indicate mixing between the quartz diorite and more felsic melts with lower 176Hf/ 177Hf. Major changes in 176Hf/ 177Hf correlate with discontinuous changes in the trace-element composition and morphology of the zircons, in particular the development of sector zoning that suggests rapid disequilibrium crystallisation. We suggest that the magma mixing recorded by the changes in 176Hf/ 177Hf occurred during transport in magma conduits. The in-situ analysis of Hf-isotopic stratigraphy in zircons is a new and powerful tool for

  5. Inherited igneous zircons in jadeitite predate high-pressure metamorphism and jadeitite formation in the Jagua Clara serpentinite mélange of the Rio San Juan Complex (Dominican Republic)

    NASA Astrophysics Data System (ADS)

    Hertwig, Andreas; McClelland, William C.; Kitajima, Kouki; Schertl, Hans-Peter; Maresch, Walter V.; Stanek, Klaus; Valley, John W.; Sergeev, Sergey A.

    2016-05-01

    This study utilizes zircon SIMS U-Pb dating, REE and trace-element analysis as well as oxygen isotope ratios of zircon to distinguish jadeite-rich rocks that formed by direct crystallization from a hydrous fluid from those that represent products of a metasomatic replacement process. Zircon was separated from a concordant jadeitite layer and its blueschist host, as well as from loose blocks of albite-jadeite rock and jadeitite that were all collected from the Jagua Clara serpentinite-matrix mélange in the northern Dominican Republic. In the concordant jadeitite layer, three groups of zircon domains were distinguished based on both age as well as geochemical and oxygen isotope values: age groups old (117.1 ± 0.9 Ma), intermediate (three dates: 90.6, 97.3, 106.0 Ma) and young (77.6 ± 1.3 Ma). Zircon populations from the blueschist host as well as the other three jadeite-rich samples generally match zircon domains of the old age group in age as well as geochemistry and oxygen isotope ratios. Moreover, these older zircon populations are indistinguishable from zircon typical of igneous oceanic crust and hence are probably inherited from igneous protoliths of the jadeite-rich rocks. Therefore, the results suggest that all investigated jadeite-rich rocks were formed by a metasomatic replacement process. The younger domains might signal actual ages of jadeitite formation, but there is no unequivocal proof for coeval zircon-jadeite growth.

  6. The Paleoproterozoic Singo granite in south-central Uganda revealed as a nested igneous ring complex using geophysical data

    NASA Astrophysics Data System (ADS)

    Abdelsalam, Mohamed G.; Katumwehe, Andrew B.; Atekwana, Estella A.; Le Pera, Alan K.; Achang, Mercy

    2016-04-01

    We used high-resolution airborne magnetic and radiometric data and satellite gravity data to investigate the form of occurrence of the Paleoproterozoic Singo granite in west-central Uganda. This granitic body covers an area of ∼700 km2, intrudes Paleoproterozoic crystalline rocks and overlain by Paleoproterozoic-Mesoproterozoic sedimentary rocks, both of which belong to the Rwenzori terrane, and it is host to hydrothermally-formed economic minerals such as gold and tungsten. Our analysis provided unprecedented geometrical details of the granitic body and revealed the following: (1) the margins of the Singo granite are characterized by a higher magnetic signature compared to the interior of the granitic body as well as the surroundings. These anomalies are apparent in both the total magnetic field and horizontal derivative images and define eight overlapping ring features. (2) the depth continuation of these magnetic anomalies define outward but steeply-dipping features as indicated by the tilt images extracted from the airborne magnetic data. This is further supported by forward modeling of the magnetic and gravity data. (3) the Singo granite is characterized by relatively high and evenly-distributed equivalent concentration of Uranium (eU) and Thorium (eTh) compared to the surroundings and this is apparent in the Potassium (K)-eTh-eU radiometric ternary image. (4) the granitic body is defined by a gravity low anomaly that persisted to a depth of three km as shown by the Bouguer anomaly image and its five km upward continuation. We used these observations to identify this granitic body as a nested igneous ring complex and we refer to it as the Singo Igneous Ring Complex (SIRC). We further interpreted the eight ring structures as individual igneous ring complexes aligned in an E-W and NE-SW direction and these were developed due to repeated calderas collapse. Additionally, we interpreted the ring-shaped magnetic anomalies as due to hydrothermally-altered margins

  7. Morally relevant potential.

    PubMed

    Hershenov, David B; Hershenov, Rose J

    2015-03-01

    Fetuses and infants are said to warrant protecting because of their potential. But valuing potential supposedly leads to absurdities like protecting cells that could be technologically altered to develop into persons. This can be avoided by recognising that morally relevant potential is determined by what is presently healthy development (proper functioning) for an organism. The only interests of mindless organisms are in the flourishing that necessarily depends upon their healthy functioning. They can be harmed when those interests are frustrated. We criticise McMahan for claiming that harm is instead a function of the degree of psychological ties to the future. PMID:24570396

  8. The pre-Caledonian Large Igneous Province and the North Atlantic Wilson Cycle

    NASA Astrophysics Data System (ADS)

    Tegner, Christian; Andersen, Torgeir B.; Corfu, Fernando; Planke, Sverre; Jørgen Kjøll, Hans; Torsvik, Trond H.

    2016-04-01

    Magmatism of the first known rifting phase of the North Atlantic Wilson Cycle is surprisingly well preserved in the Caledonian nappes of central Scandinavia. The Särv and Seve Nappes are characterised by spectacular dyke complexes originally emplaced into continental sediments along the rifted margin of Iapetus. The intensity and structure of the pre-Caledonian Dyke Complex is comparable to that of the present passive margins of the North Atlantic large igneous province (NALIP) and U-Pb ages of 610-590 Ma suggest magmatism was short-lived. It can be described as a pre-Caledonian large igneous province (CLIP). To constrain the origin of CLIP magmatism we: (1) re-visited the dyke complexes of the Sarek, Kebnekaise and Tornetrask mountains of North Sweden; (2) compiled new and published geochemical data for the more than 950 km long, magma-rich segment of the Scandinavian Caledonides; and (3) extended reconstructions of the paleo-position of Baltica back to 600 Ma. Although the appearance of the dykes ranges from garnet amphibolite gneiss to pristine magmatic intrusions, all bulk rock compositions largely reflect the original magmatic rock. The compiled dataset includes 584 analyses that essentially forms a coherent suite of tholeiitic ferrobasalt (2-12 wt% MgO, 45-54 wt% SiO2; 6-16 wt% FeOtot; 0.7-4.0 wt% TiO2) akin to LIP basalts such as those of NALIP (61-54 Ma). A few samples (<20) are significantly contaminated with crust, but most are largely uncontaminated. The delta Nb value is a proxy for geochemical enrichment based on Nb-Zr-Y systematics and was defined for the present-day North Atlantic system to distinguish enriched Iceland basalts (positive delta Nb) from normal MORB basalts (negative delta Nb). The CLIP dykes are dominantly enriched with positive delta Nb (-0.07 to +0.9) in the central and southern portion, but stretching to more negative values (-0.6 to +0.5) in the northern portion (Sarek, Kebnekaise, Tornetrask). The few available rare earth element

  9. Igneous Crystallization Beginning at 20 km Beneath the Mid-Atlantic Ridge, 14 to 16 N

    NASA Astrophysics Data System (ADS)

    Kelemen, P.

    2003-12-01

    ODP Leg 209 drilled 19 holes at 8 sites along the Mid-Atlantic Ridge from 14° 43 to 15° 44 N. All sites were previously surveyed by submersible, and were chosen to be < 200 m from peridotite or dunite exposed on the seafloor; outcrops of gabbroic rock were also near some sites. One primary goal of Leg 209 was to constrain melt migration and igneous petrogenesis in this region where residual peridotites are exposed on both sides of the Ridge axis. At Sites 1269 and 1273, we penetrated 112 m of basaltic rubble; recovery was poor (3.7 m) and holes unstable, so drilling was terminated. Lavas form nearly horizontal surfaces overlying cliffs exposing peridotite and gabbro. At 6 other sites, we drilled a mixture of residual peridotite and gabbroic rocks intrusive into peridotite. We penetrated 1075 meters at these 6 sites, and recovered 354 m of core. Drilling at Sites 1268, 1270, 1271 and 1272 recovered 25% gabbroic rocks and 75% residual mantle peridotite. Core from Site 1274 is mainly residual peridotite, with a few m-scale gabbroic intrusions. Core from Site 1275 is mainly gabbroic, but contains 24% poikilitic lherzolite interpreted as residual peridotite "impregnated" by plagioclase and pyroxene crystallized from melt migrating along olivine grain boundaries; these impregnated peridotites were later intruded by evolved gabbros. Impregnated peridotites are also common at Site 1271, and present at Sites 1268 and 1270. The overall proportion of gabbroic rocks versus residual peridotites from these 6 sites is similar to previous dredging and submersible sampling in the area. The proportion of gabbro is larger than in"amagmatic" regions on the ultra-slow spreading SWIR and Gakkel Ridges. Impregnated peridotites from Site 1275 have "equilibrated" textures and contain olivine, 2 pyroxenes, plag and Cr-rich spinel. Their whole rock Mg#, Cr# and Ni are high, extending to residual peridotite values. 87 MORB glasses from 14 to 16° N with Mg# from 60 to 73 [from PetDB] could

  10. Supercontinent Cyclicity: Relevant Data, Constraints, Limitations and Aspects Requiring Particular Attention

    NASA Astrophysics Data System (ADS)

    Eglington, B. M.; Evans, D. A.; Pehrsson, S. J.; Li, Z. X.

    2015-12-01

    Much data and information have been collected in recent years which have contributed to ideas on the apparently cyclical development of supercontinents since at least the late Archaean. Unfortunately, many of the datasets do not permit direct comparison or are limited in either spatial or temporal extent. Concerted efforts have been made in several IGCP project (440, 509 and now 648) to address some of these issues and to facilitate more consistent data compilation and availability, especially for geochronology, regional geology, large igneous provinces and ore deposits. Existing and new compilations for palaeomagnetics and geochemistry are being added to these existing systems so as to facilitate interoperability and querying. Geochronology for igneous and metamorphic material provides clear evidence for cyclical events and permits distinctions not evident in detrital zircon spectra. Alternative ways to process data permit more robust interpretations so as to partly overcome sample bias related to preservation. The growing dataset also permits direct quantitative identification of potential provenance sources for detrital studies, drawing on information from multiple continents where necessary. When overlayed on a developing plate reconstruction model back to the early Proterozoic, these and other data provide important constraints on model validity. Spatial patterns for igneous and metamorphic activity, geochemical signature of igneous intrusions and of ore deposit type provide important additional constraints. Plate reconstruction models which require the presence of all known crustal blocks and continual integrity across multiple age steps both better constrain feasible models and identify critical blocks for which additional information are essential. They also demonstrate the importance of linear arcs when cosntraining permissible plate motions.Modern reconstruction software such as Paleogis and GPlates allow one to effectively visualise an evolving earth

  11. Concise Atlas of the Solar System (11): Petrographic Textures and Evolutionary Processes from the Chondritic Parent Bodies, Moon and Mars

    NASA Astrophysics Data System (ADS)

    Bérczi, Sz.; Gucsik, A.; Hargitai, H.; Józsa, S.; Kereszturi, A.; Nagy, Sz.; Szakmány, J.

    2009-03-01

    The 11th atlas of the Solar System helps students in a systematic approach to petrographic textures of planetary materials of processes on asteroids, Moon and Mars, arranged in their igneous units of their geological settings in the parent body.

  12. Igneous mineralogy at Bradbury Rise: The first ChemCam campaign at Gale crater

    NASA Astrophysics Data System (ADS)

    Sautter, V.; Fabre, C.; Forni, O.; Toplis, M. J.; Cousin, A.; Ollila, A. M.; Meslin, P. Y.; Maurice, S.; Wiens, R. C.; Baratoux, D.; Mangold, N.; Le Mouélic, S.; Gasnault, O.; Berger, G.; Lasue, J.; Anderson, R. A.; Lewin, E.; Schmidt, M.; Dyar, D.; Ehlmann, B. L.; Bridges, J.; Clark, B.; Pinet, P.

    2014-01-01

    and compositional analyses using Chemistry Camera (ChemCam) remote microimager and laser-induced breakdown spectroscopy (LIBS) have been performed on five float rocks and coarse gravels along the first 100 m of the Curiosity traverse at Bradbury Rise. ChemCam, the first LIBS instrument sent to another planet, offers the opportunity to assess mineralogic diversity at grain-size scales (~ 100 µm) and, from this, lithologic diversity. Depth profiling indicates that targets are relatively free of surface coatings. One type of igneous rock is volcanic and includes both aphanitic (Coronation) and porphyritic (Mara) samples. The porphyritic sample shows dark grains that are likely pyroxene megacrysts in a fine-grained mesostasis containing andesine needles. Both types have magnesium-poor basaltic compositions and in this respect are similar to the evolved Jake Matijevic rock analyzed further along the Curiosity traverse both with Alpha-Particle X-ray Spectrometer and ChemCam instruments. The second rock type encountered is a coarse-grained intrusive rock (Thor Lake) showing equigranular texture with millimeter size crystals of feldspars and Fe-Ti oxides. Such a rock is not unique at Gale as the surrounding coarse gravels (such as Beaulieu) and the conglomerate Link are dominated by feldspathic (andesine-bytownite) clasts. Finally, alkali feldspar compositions associated with a silica polymorph have been analyzed in fractured filling material of Preble rock and in Stark, a putative pumice or an impact melt. These observations document magmatic diversity at Gale and describe the first fragments of feldspar-rich lithologies (possibly an anorthosite) that may be ancient crust transported from the crater rim and now forming float rocks, coarse gravel, or conglomerate clasts.

  13. Igneous petrology of the new ureilites Nova 001 and Nullarbor 010

    NASA Technical Reports Server (NTRS)

    Triman, Allan H.; Berkley, John L.

    1994-01-01

    The Nova 001 (= Nuevo Mercurio (b)) and Nullarbor 010 meteorites are ureilites, both of which contain euhedral graphite crystals. The bulk of the meteorites are olivine (Fo79) and pyroxenes (Wo9En73Fs18, Wo3En77Fs20), with a few percent graphite and minor amounts of troilite, Ni-Fe metal, and possibly diamond. The rims of olivine grains are reduced (to Fo91) and contain abundant blebs of Fe metal. Silicate mineral grains are equant, anhedral, up to 2 mm across, and lack obvious preferred orientations. Euhedral graphite crystals (to 1 mm x 0.3 mm) are present at silicate grain boundaries, along boundaries and protruding into the silicates, and entirely within silicate mineral grains. Graphite euhedra are also present as radiating clusters and groups of parallel plates grains embedded in olivine; no other ureilite has comparable graphite textures. Minute lumps within graphite grains are possible diamond, inferred to be a result of shock. Other shock effects are limited to undulatory extinction and fracturing. Both ureilites have been weathered significantly. Considering their similar mineralogies, identical mineral compositions, and identical unusual textures, Nova 001 and Nullarbor 010 are probably paired. Based on olivine compositions, Nova 001 and Nullarbor 010 are in Group 1 (FeO-rich) of Berkley et al. (1980). Silicate mineral compositions are consistent with those of others known ureilites. The presence of euhedral graphite crystals within the silicate minerals is consistent with an igneous origin, and suggests that large proportions of silicate magma were present locally and crystallized in situ.

  14. Igneous petrogenesis and tectonic setting of granitic rocks from the eastern Blue Ridge, Alabama Appalachians

    SciTech Connect

    Drummond, M.S. . Geology Dept.); Allison, D.T. . Geology Dept.); Tull, J.F. . Geology Dept.); Bieler, D.B. . Geology Dept.)

    1994-03-01

    A span of 150 my of orogenic activity is recorded within the granitic rocks of the eastern Blue Ridge of Alabama (EBR). Four discrete episodes of plutonism can be differentiated, each event exhibiting distinct field relations and geochemical signatures. (1) Penobscotian stage: this initial stage of plutonic activity is represented by the Elkahatchee Quartz Diorite (EQD), a premetamorphic (495 Ma) batholith and the largest intrusive complex (880 km[sup 2]) exposed in the Blue Ridge. Calc-alkaline I-type tonalite-granodiorite are the principal lithologies, with subordinate cumulate hbl-bt diorite, metadacite, granite and trondhjemite. The parental tonalitic magmas are interpreted to have been derived from a subducted MORB source under eclogite to get amphibolite conditions. (2) Taconic stage: the Kowaliga augen gneiss (KAG) and the Zana granite gneiss (ZG) are 460 Ma granitic bodies that reside in the SE extremity and structurally highest portion of the EBR. Both of these bodies are pre-metamorphic with strongly elongate sill- and pod-like shapes concordant with S[sub 1] foliation. Granite and granodiorite comprise the bulk of the KAG. (3) Acadian stage: Rockford Granite (RG), Bluff springs Granite (BSG, 366 Ma), and Almond Trondhjemite represent a suite of pre- to syn-metamorphic granitic intrusions. (4) late-Acadian stage: The Blakes Ferry pluton (BFP) is a post-kinematic pluton displaying spectacular by schlieren igneous flow structures, but no metamorphic fabric. The pluton's age can be bracketed between a 366 Ma age on the BSG and a 324 Ma K-Ar muscovite age on the BFP. BFP's petrogenesis has involved partial melting a MORB source followed by assimilation of metasedimentary host rock.

  15. Thermobarometric studies on the Levack Gneisses: Footwall rocks to the Sudbury Igneous Complex

    NASA Technical Reports Server (NTRS)

    James, R. S.; Peredery, W.; Sweeny, J. M.

    1992-01-01

    Granulite and amphibolite facies gneisses and migmatites of the Levack Gneiss Complex occupy a zone up to 8 km wide around the northern part of the Sudbury Igneous Complex (SIC). Orthopyroxene- and garnet-bearing tonalitic and semipelitic assemblages of granulite facies grade occur within 3 km of the SIC together with lenses of mafic and pyroxenitic rock compositions normally represented by an amphibole +/- cpx-rich assemblage; amphibolite facies assemblages dominate elsewhere in this terrain. These 2.711-Ga gneisses were introduced by (1) the Cartier Granite Batholith during late Archaean to early Proterozoic time and (2) the SIC, at 1.85 Ga, which produced a contact aureole 1-1.5 km wide in which pyroxene hornfelses are common within 200-300 m of the contact. A suite of 12 samples including both the opx-gt and amphibole-rich rock compositions have been studied. Garnets in the semipelitic gneisses are variably replaced by a plg-bio assemblage. Thermobarometric calculations using a variety of barometers and thermometers reported in the literature suggest that the granulite facies assemblages formed at depths in the 21-28 km range (6-8 kbar). Textures and mineral chemistry in the garnet-bearing semipelitic rocks indicate that this terrain underwent a second metamorphic event during uplift to depth in the 5-11 km range (2-3 kbar) and at temperatures as low as 500-550 C. This latter event is distinct from thermal recrystallization caused by the emplacement of the SIC; it probably represents metamorphism attributable to intrusion of the Cartier Granite Batholith. These data allow two interpretations for the crustal uplift of the Levack Gneisses: (1) The gneisses were tectonically uplifted prior to the Sudbury Event (due to intrusion of the Cartier Batholith); or (2) the gneisses were raised to epizonal levels as a result of meteorite impact at 1.85 Ga.

  16. End-to-End Models for Effects of System Noise on LIMS Analysis of Igneous Rocks

    SciTech Connect

    Clegg, Samuel M; Bender, Steven; Wiens, R. C.; Carmosino, Marco L; Speicher, Elly A; Dyar, M. D.

    2010-12-23

    The ChemCam instrument on the Mars Science Laboratory will be the first extraterrestial deployment of laser-induced breakdown spectroscopy (UBS) for remote geochemical analysis. LIBS instruments are also being proposed for future NASA missions. In quantitative LIBS applications using multivariate analysis techniques, it is essential to understand the effects of key instrument parameters and their variability on the elemental predictions. Baseline experiments were run on a laboratory instrument in conditions reproducing ChemCam performance on Mars. These experiments employed Nd:YAG laser producing 17 mJ/pulse on target and an with a 200 {micro}m FWHM spot size on the surface of a sample. The emission is collected by a telescope, imaged on a fiber optic and then interfaced to a demultiplexer capable of >40% transmission into each spectrometer. We report here on an integrated end-to-end system performance model that simulates the effects of output signal degradation that might result from the input signal chain and the impact on multivariate model predictions. There are two approaches to modifying signal to noise (SNR): degrade the signal and/or increase the noise. Ishibashi used a much smaller data set to show that the addition of noise had significant impact while degradation of spectral resolution had much less impact on accuracy and precision. Here, we specifically focus on aspects of remote LIBS instrument performance as they relate to various types of signal degradation. To assess the sensitivity of LIBS analysis to signal-to-noise ratio (SNR) and spectral resolution, the signal in each spectrum from a suite of 50 laboratory spectra of igneous rocks was variably degraded by increasing the peak widths (simulating misalignment) and decreasing the spectral amplitude (simulating decreases in SNR).

  17. Felsic Igneous Rocks at Gale Crater : a Comparison with Lithic Clasts in NWA 7533

    NASA Astrophysics Data System (ADS)

    Sautter, V.; Wiens, R. C.; Toplis, M. J.; Cousin, A.; Forni, O.; Fabre, C.

    2014-12-01

    Curiosity rover landed at Gale, an early Hesperian age crater formed within Noachian rocks. In Hummocky plain, more than half of the igneous floats rocks are highly alkaline rocks (Stolper et al. doi: 101126/science.12239463, Schmidt et al. doi: 10.1002/2013JE004481) and feldspar-bearing rocks (Sautter et al. doi: 10.1002/2013JE00447). ChemCam observations at sub-millimeter scale show that these samples contain a significant feldspar component, either associated with LCP in gabbroic texture or with augite in effusive rocks defining an alkaline K-feldspar-bearing suite: basanite, trachy-andesite with porphyritic texture and syenitic rock with apahnitic texture. This series likely resulted from differentiation of liquids produced by low degrees of partial melting of primitive mantle. These rocks are float rocks or occurred as clast in conglomerate suggesting a provenance from Gale crater rim. NWA 7533 is the first Noachian breccia sampling the southern hemisphere Martian regolith. It is a polymict breccia with leucocratic clasts including zircon with 4.4 Ga ages Humayun et al., doi :10.1038/nature). The alkali basaltic evolved clasts contain two feldspars (alkali and plagioclase) and modal recombination gives a basaltic trachy-andesite, gabbroic, trachy-andesite and mugearite clast (Agee et al. doi: 10.1126/science. 1228858). Noritic clasts contain andesine, LCP, and Cr-magnetite. The monzonitic/mugearitic-evolved clasts are composed of alkali feldspar, plagioclase, augite, Ti-Magnetite, Cl-apatite and zircon. These clasts would represent products of Martian crust emplaced at 4.5 Ga and re-melted at 4.4 Ga (Humayun et al., doi :10.1038/nature). The leucocratic clasts of the Noachian SNC breccia will be compared with evolved lithology encountered at Gale crater and products of Noachian magmatism will be discussed.

  18. Development of Clinopyroxene as an Igneous Geospeedometer Using NanoSIMS

    NASA Astrophysics Data System (ADS)

    Brugman, K.; Till, C. B.; Bose, M.; Hervig, R. L.

    2015-12-01

    Geospeedometry, the quantification of timescales from diffusional relaxation of compositional zoning in minerals, is usually implemented using quartz, feldspar, and olivine. Clinopyroxene (cpx), commonly found in both igneous and metamorphic rocks as well as in meteorites, could also be a powerful tool for diffusion-related applications, once the appropriate suite of magmaphile elements with different diffusivities is identified—especially where the initial condition cannot be assumed to be a step function. Here we develop the use of cpx as a geospeedometer in rhyolitic magma by investigating slow diffusing elements via SIMS and NanoSIMS analyses using Yellowstone Plateau rhyolite lavas as a test case. LA-ICPMS analyses identified slow diffusing elements with resolvable abundances in the Yellowstone cpx; Ce and Dy were the best candidates, because experimental studies demonstrate they diffuse 12-88 times slower at a given temperature than elements such as Fe-Mg, which are typically used for diffusion dating in pyroxene. SIMS profiles with ≤ 8 micron resolution across intracrystalline zone boundaries reveal Ce and Dy abundances of ~175 ppm and ~78 ppm respectively, but also motivate analyses with higher spatial resolution in order to quantify concentration gradients for diffusion modeling. Subsequent NanoSIMS profiles at 0.2-1 micron spacing across intracrystalline zone boundaries capture Ce and Dy gradients that can be used to provide rejuventation-eruption timescales from the Yellowstone cpx. SIMS analyses employing energy filtering vs. those collected at full transimission both replicate the cpx Ce and Dy zoning and indicate there are not significant mass interferences for Ce and Dy, confirming that the NanoSIMS results replicate true intracrystalline variation. In addition, NanoSIMS Si, Mg, Fe, Ce, and Dy distribution maps of individual exsolution lamellae from the cpx cores provide information about the cooling history of the cpx.

  19. Emplacement and Eruption Style in the Franklin Large Igneous Province, Victoria Island, Arctic Canada

    NASA Astrophysics Data System (ADS)

    Bedard, J. H.; Williamson, N.; Dell'Oro, T. A.; Hayes, B.; Hryciuk, M.; Winpenny, A.; Scoates, J. S.; Weis, D. A.; Nabelek, P. I.; Naslund, H. R.; MacDonald, W. D.

    2011-12-01

    The Neoproterozoic Franklin large igneous province preserves up to 1.1 km thickness of basaltic volcanics (Natkusiak Fm.). The Natkusiak volcanics include basal agglutinate and local hyaloclastite breccias and pillows, lensoid or sheet flows, some picritic, and lahar deposits that seem to infill paleo-valleys. The overlying main series lavas are mostly subareal sheet flows and exhibit cycles of upwardly decreasing MgO. Localized vent facies include unconsolidated scoria and bombs, spatter, and fumarolic malachite/zeolite around native Cu veins. Lateral trace element chemical heterogeneity implies eruption through multiple vents with distinct plumbing systems. The underlying exposed 3-4 km of the Shaler Supergroup are dolostones, sandstones, gypsum evaporites and shales, which are riddled with sills (most 20-50m, up to 100m). Sills constitute 50-75% of the section in most places, and belong to two distinct geochemical subtypes. A heterogeneous LREE-enriched facies includes sills with olivine-rich bases. A more homogeneous diabasic subtype has flatter REE patterns and occurs higher in the section. The oft-reported saucer-shaped sill morphology does not occur in the Franklin sills, which tend to be concordant over 10s of km distance. In many places, up-section transgressions appear to be structurally controlled by pre-existing faults that guided magma ascent and may have modulated reactivation and injection of olivine-rich slurries into pre-existing sills. The roof-zones of upward transgressions are injected with arcuate dikes on various scales (1m to 1 km), and are often associated with cataclasites, oxide-sulfide skarns and calc-silicates. These reflect the complexity of melt-driven fracture propagation, varying host ductility, fluctuation of magma pressure, and expulsion of melt and fluids from cooling sills. Some of these intrusions are enriched in sulphide minerals, possibly the result of assimilation of S-rich host rocks.

  20. Playing jigsaw with large igneous provinces - a plate-tectonic reconstruction of Ontong Java Nui

    NASA Astrophysics Data System (ADS)

    Hochmuth, Katharina; Gohl, Karsten; Uenzelmann-Neben, Gabriele; Werner, Reinhard

    2015-04-01

    Ontong Java Nui is a Cretaceous large igneous province (LIP), which was rifted apart into various smaller plateaus shortly after its emplacement around 125 Ma in the central Pacific. It incorporated the Ontong Java Plateau, the Hikurangi Plateau and the Manihiki Plateau as well as multiple smaller fragments, which have been subducted. Its size has been estimated to be approximately 0.8% of the Earth's surface. A volcanic edifice of this size has potentially had a great impact on the environment such as its CO2 release. The break-up of the "Super"-LIP is poorly constrained, because the break-up and subsequent seafloor spreading occurred within the Cretaceous Quiet Period. The Manihiki Plateau is presumably the centerpiece of this "Super"-LIP and shows by its margins and internal fragmentation that its tectonic and volcanic activity is related to the break-up of Ontong Java Nui. By incorporating two new seismic refraction/wide-angle reflection lines across two of the main sub-plateaus of the Manihiki Plateau, we can classify the break-up modes of the individual margins of the Manihiki Plateau. The Western Plateaus experienced crustal stretching due to the westward motion of the Ontong Java Plateau. The High Plateau shows sharp strike-slip movements at its eastern boundary towards an earlier part of Ontong Java Nui, which is has been subducted, and a rifted margin with a strong volcanic overprint at its southern edges towards the Hikurangi Plateau. These observations allow us a re-examination of the conjugate margins of the Hikurangi Plateau and the Ontong Java Plateau. The repositioning of the different plateaus leads to the conclusion that Ontong Java Nui was larger (~1.2% of the Earth's surface at emplacement) than previously anticipated. We use these finding to improve the plate tectonic reconstruction of the Cretaceous Pacific and to illuminate the role of the LIPs within the plate tectonic circuit in the western and central Pacific.

  1. TIR Spectroscopy: Looking for Igneous Rocks on the Surface of Mercury.

    NASA Astrophysics Data System (ADS)

    Ferrari, S.; Maturilli, A.; Carli, C.; Helbert, J.; D'Amore, M.; Nestola, F.; Zorzi, F.; Hiesinger, H.

    2014-12-01

    Recent MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) findings, corroborated by petrologic modeling, reviewed the surface composition of Mercury as mainly constituted by low-Fe and Mg-rich basalts. This interpretation dismisses the previously assessed widespread presence of more felsic materials - as on the Moon's surface - leaving open the question of the crust petrogenesis of Mercury. Assessing the presence of a differentiated crust on the surface of Mercury is among the intrinsic objectives of the next ESA/JAXA BepiColombo mission to Mercury. The ESA Mercury Planetary Orbiter will carry the Mercury Radiometer and Thermal Imaging Spectrometer (MERTIS, 7-14 µm), which will map the surface mineralogical composition of the planet. The interpretation of spectra collected along a wide range of daily surface temperatures is complicated by the relocation of the band minima depending on the temperature (e.g., Helbert et al. 2013). In addition, the simultaneous presence of different minerals, each one with its characteristic thermal expansion coefficient, results in a more difficult interpretation of the spectra. In this work we examine the spectral variations of linear mixtures of plagioclase and pyroxenes that most likely could be present in the differentiated igneous crust of Mercury, in addition to the T-dependent spectral variations of the single constituents. Furthermore we show how two different thermal expansion coefficients combined in the same sample reveal in a thermal infrared spectrum. To this aim we measure high-T emissivity - up to 725K - of natural binary compositions (e.g., anorthosite, gabbro, norite) and their single-phase components, whose chemistries are provided by microprobe analyses. Besides spectroscopy, all the provided samples are analyzed before and after the heat-treatment using X-Ray Diffraction, in order to verify any possible variation due to the annealing.

  2. Flexure and faulting of sedimentary host rocks during growth of igneous domes, Henry Mountains, Utah

    USGS Publications Warehouse

    Jackson, M.D.; Pollard, D.D.

    1990-01-01

    A sequence of sedimentary rocks about 4 km thick was bent, stretched and uplifted during the growth of three igneous domes in the southern Henry Mountains. Mount Holmes, Mount Ellsworth and Mount Hillers are all about 12 km in diameter, but the amplitudes of their domes are about 1.2, 1.85 and 3.0 km, respectively. These mountains record successive stages in the inflation of near-surface diorite intrusions that are probably laccolithic in origin. The host rocks deformed along networks of outcrop-scale faults, or deformation bands, marked by crushed grains, consolidation of the porous sandstone and small displacements of sedimentary beds. Zones of deformation bands oriented parallel to the beds and forma