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Sample records for igneous processes relevant

  1. Potential Igneous Processes Relevant to the Yucca Mountain Repository: Intrusive-Release Scenario

    SciTech Connect

    Apted, M.; Kozak, M.; Kessler, J.

    2006-07-01

    As part of the Department of Energy's (DOE's) license application for the proposed high level radioactive waste and spent nuclear fuel repository proposed for Yucca Mountain, Nevada, the DOE must provide probabilistic dose estimates after repository closure. These estimates must consider all events and processes that are considered reasonably likely to occur, including potential igneous events [1-4]. Current estimates of the probability of a future igneous event intruding through the proposed repository [5] are just high enough that dose consequences must be estimated. Estimates of igneous-event probability and the extent of any radionuclide release resulting from such an event have drawn considerable attention. In general, these estimates have included multiple, compounded conservatisms resulting in significant predicted dose consequences compared to dose consequences from the nominal release scenarios. This new independent study conducted for the Electric Power Research Institute (EPRI) provides a more realistic estimate of the likelihood and magnitude of doses to the public should such a low-probability event occur [6]. Analyses summarized here indicate that, under any reasonable expected conditions for a magmatic intrusion, the contribution to peak dose from such an igneous intrusion event would not affect peak dose estimates over the long term. (authors)

  2. Variations in magmatic processes among igneous asteroids

    NASA Technical Reports Server (NTRS)

    Gaffey, M. J.

    1991-01-01

    Six asteroid classes (types V, E, A, R, M, S) are composed primarily of differentiated assemblages produced by igneous processes within their parent planetesimals. These are identified by surface materials which deviate from a chondritic composition to a degree that require igneous chemical fractionation processes. There are large variations among these igneous asteroids in the peak temperatures attained, in the efficiency of magmatic phase separation, and in the depth within the original parent body exposed at the present surface. These variations provide important constraints on the nature of asteroidal heating events, on the differentiation processes within small planetary bodies, and on the disruption of those parent bodies. Variations due to depth within the parent body and due to degree of magmatic differentiation are detailed.

  3. 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.

  4. Magmatic-hydrothermal molybdenum isotope fractionation and its relevance to the igneous crustal signature

    NASA Astrophysics Data System (ADS)

    Greber, Nicolas D.; Pettke, Thomas; Nägler, Thomas F.

    2014-03-01

    We analysed the Mo isotope composition of a comprehensive series of molybdenite samples from the porphyry-type Questa deposit (NM, USA), as well as one rhyolite and one granite sample, directly associated with the Mo mineralization. The δ98Mo of the molybdenites ranges between - 0.48‰ and + 0.40‰, with a median at - 0.05‰. The median Mo isotope composition increases from early magmatic (- 0.29‰) to hydrothermal (- 0.05‰) breccia mineralization (median bulk breccia = - 0.17‰) to late stockwork veining (+ 0.22‰). Moreover, variations of up to 0.34‰ are found between different molybdenite crystals within an individual hand specimen. The rhyolite sample with 0.12 μg g- 1 Mo has δ98Mo = - 0.57‰ and is lighter than all molybdenites from the Questa deposit, interpreted to represent the igneous leftover after aqueous ore fluid exsolution. We recognize three Mo isotope fractionation processes that occur between about 700 and 350 °C, affecting the Mo isotope composition of magmatic-hydrothermal molybdenites. ∆1Mo: Minerals preferentially incorporate light Mo isotopes during progressive fractional crystallization in subvolcanic magma reservoirs, leaving behind a melt enriched in heavy Mo isotopes. ∆2Mo: Magmatic-hydrothermal fluids preferentially incorporate heavy Mo isotopes upon fluid exsolution. ∆3Mo: Light Mo isotopes get preferentially incorporated in molybdenite during crystallization from an aqueous fluid, leaving behind a hydrothermal fluid that gets heavier with progressive molybdenite crystallization. The sum of all three fractionation processes produces molybdenites that record heavier δ98Mo compositions than their source magmas. This implies that the mean δ98Mo of molybdenites published so far (~ 0.4‰) likely represents a maximum value for the Mo isotope composition of Phanerozoic igneous upper crust.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Intrusive LIPs: Deep crustal magmatic processes during the emplacement of Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Richards, M. A.; Karlstrom, L.

    2011-12-01

    Large Igneous Provinces (LIPs) are characterized by magmatic activity on two distinct timescales. While these provinces have total active lifetimes of order 10-30 Ma, most of the erupted volume is emplaced within <1 Ma in many cases. The latter timescale is likely controlled by magmatic intrusion/evolution processes within the deep crust. We present seismic evidence for 5-15 km thick Moho-level ultramafic intrusive/cumulate layers underlying Phanerozoic LIPs worldwide [Ridley and Richards, 2010]. These deep crustal bodies are both observed and predicted to have volumes at least as large as the extrusive components of flood volcanism. The evidence for these layers is particularly clear for oceanic LIPs (plateaus). We hypothesize that thermally activated creep of the lower crust due to magma chamber emplacement controls a transition from largely extrusive to largely intrusive magmatism during mantle plume impingement on the lithosphere [Karlstrom and Richards, 2011]. We explore this hypothesis by modeling the thermomechanical evolution of Moho-level magma chambers. Comparing the timescale for viscoelastic relaxation of intrusion-related stresses with the timescale for sill formation and magma differentiation, we find that fracture processes leading to diking from Moho levels may plausibly be shut off on a timescale of ~1 Ma. Continued melt influx therefore results in intrusive magmatism, which may be manifest as plateau growth in oceanic settings. We suggest that maximum intrusion size may be limited by crustal thickness, resulting in smaller volume individual eruptions in oceanic versus continental LIPs.

  10. Igpet software for modeling igneous processes: examples of application using the open educational version

    NASA Astrophysics Data System (ADS)

    Carr, Michael J.; Gazel, Esteban

    2016-09-01

    We provide here an open version of Igpet software, called t-Igpet to emphasize its application for teaching and research in forward modeling of igneous geochemistry. There are three programs, a norm utility, a petrologic mixing program using least squares and Igpet, a graphics program that includes many forms of numerical modeling. Igpet is a multifaceted tool that provides the following basic capabilities: igneous rock identification using the IUGS (International Union of Geological Sciences) classification and several supplementary diagrams; tectonic discrimination diagrams; pseudo-quaternary projections; least squares fitting of lines, polynomials and hyperbolae; magma mixing using two endmembers, histograms, x-y plots, ternary plots and spider-diagrams. The advanced capabilities of Igpet are multi-element mixing and magma evolution modeling. Mixing models are particularly useful for understanding the isotopic variations in rock suites that evolved by mixing different sources. The important melting models include, batch melting, fractional melting and aggregated fractional melting. Crystallization models include equilibrium and fractional crystallization and AFC (assimilation and fractional crystallization). Theses, reports and proposals concerning igneous petrology are improved by numerical modeling. For reviewed publications some elements of modeling are practically a requirement. Our intention in providing this software is to facilitate improved communication and lower entry barriers to research, especially for students.

  11. 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.

  12. Vertically extensive and unstable magmatic systems: A unified view of igneous processes.

    PubMed

    Cashman, Katharine V; Sparks, R Stephen J; Blundy, Jonathan D

    2017-03-24

    Volcanoes are an expression of their underlying magmatic systems. Over the past three decades, the classical focus on upper crustal magma chambers has expanded to consider magmatic processes throughout the crust. A transcrustal perspective must balance slow (plate tectonic) rates of melt generation and segregation in the lower crust with new evidence for rapid melt accumulation in the upper crust before many volcanic eruptions. Reconciling these observations is engendering active debate about the physical state, spatial distribution, and longevity of melt in the crust. Here we review evidence for transcrustal magmatic systems and highlight physical processes that might affect the growth and stability of melt-rich layers, focusing particularly on conditions that cause them to destabilize, ascend, and accumulate in voluminous but ephemeral shallow magma chambers.

  13. 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.

  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. Lunar igneous intrusions.

    PubMed

    El-Baz, F

    1970-01-02

    Photographs taken from Apollo 10 and 11 reveal a number of probable igneous intrusions, including three probable dikes that crosscut the wall and floor of an unnamed 75-kilometer crater on the lunar farside. These intrusions are distinguished by their setting, textures, structures, and brightness relative to the surrounding materials. Recognition of these probable igneous intrusions in the lunar highlands slupports the indications of the heterogeneity of lunar materials and the plausibility of intrusive igneous activity, in addition to extrusive volcanism, on the moon.

  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. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Elucidating Dynamical Processes Relevant to Flow Encountering Abrupt Topography (FLEAT)

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Elucidating Dynamical Processes Relevant to Flow ...dynamical explorations using numerical models. To put the in-situ measurements in context, we plan to analyze the output from the submesoscale eddy

  3. 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…

  4. 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

  5. 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.

  6. Alteration processes in igneous rocks of the michilla mining area, coastal range, northern chile, and their relation with copper mineralisation

    NASA Astrophysics Data System (ADS)

    Oliveros, V.; Aguirre, L.; Townley, B.

    2003-04-01

    A 10 km thick homoclinal sequence of intermediate volcanic and sedimentary Jurassic rocks crops out in the Michilla mining area, Coastal Range, northern Chile (22-22°45S, 70-70°15W). Cretaceous plutons, intermediate to acid in composition, intrude this sequence together with numerous small basic to acid dykes and stocks. Main deposits are stratabound Cu-(Ag) with the ore minerals emplaced at the porous tops of the volcanic flows. However, some discordant orebodies, e.g. hydrothermal breccias, exist within the manto-type deposits. The volcanic sequence, and a minor part of the plutonic rocks, have been affected by three different alteration processes, each of them with their distinct mineral assemblages reflecting that every process was developed under different physicochemical conditions. The volcanic rocks far from the mining area are affected by a regional scale alteration process, basically isochemical. Its products are typical of a low-grade event: chl + ep +qtz + ttn (+- ab +- cal) with no ore minerals associated. The temperature interval, estimated by the chlorite geothermometer, ranges between 250 and 350°C. This alteration is either due to very low grade burial metamorphism or to hydrothermalism related to the Late Jurassic - Cretaceous plutonism. Inside the mining district the volcanic rocks are affected by a local scale alteration process originated by the intrusion of small stocks and dykes. This event is characterized by strong sodic metasomatism and minor Mg mobility. Two stages probably occurred as suggested by the two main mineral assemblages present, a propylitic (ab + ep + chl + act + ttn + qtz) and a quartz-sericitic one (ab + ser + qtz + tnn). They would reflect the changes in temperature, water/rock ratio and pH conditions during the whole process. Ore minerals related to this alteration are chalcopyrite, chalcocite and minor bornite and native silver. A temperature interval of 200-300°C is indicated by the chlorite geothermometer for the

  7. Igneous and Aqueous Processes on Mars: Evidence from Measurements of K and Th by the Mars Odyssey Gamma Ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Taylor, G. Jeffrey; Boynton, W.; Hamara, D.; Kerry, K.; Janes, D.; Keller, J.; Feldman, W.; Prettyman, T.; Reedy, R.; Brueckner, J.

    2003-01-01

    We report preliminary measurements of the concentrations of K and Th on Mars. Concentrations of K and Th and the K/Th ratio vary across the surface. Concentrations are higher than in Martian meteorites, suggesting that most of the crust formed by partial melting of enriched mantle. The average Th concentration (1.1 ppm), if applicable to the entire crust, implies a maximum thickness of about 65 km. The variation in the K/Th ratio suggests that aqueous processes have affected the chemistry of the surface.

  8. Pristine Noachian crust and key geologic transitions in the lower walls of Valles Marineris: Insights into early igneous processes on Mars

    NASA Astrophysics Data System (ADS)

    Flahaut, Jessica; Quantin, Cathy; Clenet, Harold; Allemand, Pascal; Mustard, John F.; Thomas, Pierre

    2012-09-01

    Valles Marineris is a unique vertical section through the uppermost kilometers of the martian crust. Its location, east of the Tharsis bulge, and its water-related history, fuel a great diversity of rock types in this area (Carr, M.H., Head, J.W. [2010]. Earth Planet. Sci. Lett. 294, 185-203). HiRISE and CRISM data available over the walls of the canyon were analyzed to infer the importance of magmatic and sedimentary processes through time. This contribution provides a complete morphologic and mineralogic characterization of the cross-section of rocks exposed in the canyon walls. Low-calcium pyroxene and olivine are detected in the lower portion of the walls, in association with morphologically distinct outcrops, leading to the idea that pristine Noachian crust might be exposed. Phyllosilicates are also present within the walls, but they appear to correspond to an alteration product. No proper sedimentary layers were observed within the walls of Valles Marineris at the resolution available today. All these detections are limited to the eastern portion of Valles Marineris, especially Juventae, Coprates, Capri, and Ganges chasmata. Preserved Noachian crustal material is rare on the martian surface and is rarely exposed in its pristine geologic context. Such detections lend precious information about early igneous processes. This survey also supports observations from the nearby impact crater central peaks (Quantin, C., Flahaut, J., Allemand, P. [2009]. Lunar Planet. Sci. 10; Quantin, C., Flahaut, J., Clenet, H., Allemand, P., Thomas, P. [2011]. Icarus, submitted for publication) and suggests that the western part of Valles Marineris may be cut into another material, consistent with lavas or volcanic sediments.

  9. 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

  10. 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

  11. Are classical process safety concepts relevant to nanotechnology applications?

    NASA Astrophysics Data System (ADS)

    Amyotte, Paul R.

    2011-07-01

    The answer to the question posed by the title of this paper is yes - with adaptation to the specific hazards and challenges found in the field of nanotechnology. The validity of this affirmative response is demonstrated by relating key process safety concepts to various aspects of the nanotechnology industry in which these concepts are either already practised or could be further applied. This is accomplished by drawing on the current author's experience in process safety practice and education as well as a review of the relevant literature on the safety of nanomaterials and their production. The process safety concepts selected for analysis include: (i) risk management, (ii) inherently safer design, (iii) human error and human factors, (iv) safety management systems, and (v) safety culture.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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).

  17. Information-Processing and Perceptions of Control: How Attribution Style Affects Task-Relevant Processing

    ERIC Educational Resources Information Center

    Yeigh, Tony

    2007-01-01

    This study investigated the effects of perceived controllability on information processing within Weiner's (1985, 1986) attributional model of learning. Attributional style was used to identify trait patterns of controllability for 37 university students. Task-relevant feedback on an information-processing task was then manipulated to test for…

  18. 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.

  19. Ionium dating of igneous rocks.

    PubMed

    Kigoshi, K

    1967-05-19

    Local fractionation of uranium and thorium, between minerals within a sample of igneous rock at the time of crystallization, makes it possible to date its solidification by use of ionium and uranium. Results on samples of granite, pumice, and lava suggest that this method of dating is reliable.

  20. 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)

  1. 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.

  2. 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

  3. Bursting processes in plasmas and relevant nonlinear model equations

    SciTech Connect

    Basu, B.; Coppi, B.

    1995-01-01

    Important intrinsic plasma instabilities manifest themselves in the form of periodic bursts of fluctuations rather than as a state of stationary fluctuations, which a conventional application of quasilinear theory would lead to expect. A set of coupled nonlinear equations for the time evolution of the fluctuation amplitude and of the driving factor of the relevant instability is shown to have the features necessary to reproduce the variety of bursts that are observed experimentally. These are the periodicity, the duration, and the shape of the bursts, special consideration being given to the excitation of modes by high-energy particle populations in thermalized plasmas and to a model for the transition from a bursting state to one of stationary fluctuations. A model is introduced that is relevant to the case where the spatial dependence of the mode amplitude is important. The application of the given analysis to the bursty wave emissions observed in space is discussed. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  4. Finding Relevant Items: Attentional Guidance Improves Visual Selection Processes

    NASA Astrophysics Data System (ADS)

    Stork, Sonja; Hild, Isabella; Wiesbeck, Mathey; Zaeh, Michael F.; Schubö, Anna

    In daily life and at work people are confronted with complex information. Especially elderly or disabled users might be overburdened by the amount of information and distracted by irrelevant items. Due to this, they possibly fail to find and select relevant items in visual search. This could be demotivating for the use of media like the internet or could result in an inability to achieve certain job requirements. A method for supporting performance in visual search tasks is the guidance of attention. The present study compares different methods for attentional guidance. Results show a benefit for peripheral exogenous cues realized as luminance changes in comparison to endogenous central cues. Possible applications for the proposed attentional guidance method are discussed.

  5. 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.

  6. Process theology's relevance for older survivors of domestic violence.

    PubMed

    Bowland, Sharon

    2011-01-01

    Pastoral work with survivors of domestic violence may reveal theological struggles. Understandings of scripture that reinforce a sense of powerlessness and alienation from God may contribute to an impaired relationship and limit resources for healing. One framework for re-imaging a relationship with God is process theology. This framework was applied to a case study for one survivor. The application resulted in a line of inquiry that may assist survivors in their healing process.

  7. Mineral Detector for Igneous Rocks

    NASA Astrophysics Data System (ADS)

    Ishikawa, S. T.; Hart, S. D.; Gulick, V. C.

    2010-12-01

    We present a Raman spectral analysis tool that uses machine learning algorithms to classify pure minerals in igneous rocks. Experiments show greater than 90% accuracy classifying a test set of pure minerals against a database of similar reference minerals using an artificial neural network. Efforts are currently underway to improve this tool for use as a mineral detector in rock samples, an important milestone toward autonomously classifying rocks based on spectral, and previous imaging work. Although pure mineral classification has been widely successful, applying the same methods to rocks is difficult because the spectra may represent a combination of multiple, and often competing, mineral signatures. In such cases some minerals may appear with more intensity than others resulting in masking of weaker minerals. Furthermore, with our particular spectrometer (852 nm excitation, ~50 micron spot size), minerals such as potassium feldspar fluoresce, both obscuring its characteristic Raman features and suppressing those of weaker minerals. For example, plagioclase and quartz, two key minerals for determining the composition of igneous rocks, are often hidden by minerals such as potassium feldspar and pyroxene, and are consequently underrepresented in the spectral analysis. These technicalities tend to skew the perceived composition of a rock from its actual composition. Despite these obstacles, an experiment involving a training set of 26 minerals (plagioclase, potassium feldspar, pyroxene, olivine, quartz) and a test set of 57 igneous rocks (basalt, gabbro, andesite, diorite, dacite, granodiorite, rhyolite, granite) shows that generalizations derived from their spectral data are consistent with expected trends: as rock composition goes from felsic to mafic there is a marked increase in the detection of minerals such as plagioclase and pyroxene along with a decrease in the detection of minerals such as quartz and potassium feldspar. The results suggest that phaneritic

  8. 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.

  9. EPR imaging of diffusional processes in biologically relevant polymers

    NASA Astrophysics Data System (ADS)

    Berliner, Lawrence J.; Fujii, Hirotada

    Diffusion processes in biological tissue are important problems for noninvasive investigation. As a model study, this work addresses the diffusion of an electrolyte buffer (Krebs) solution containing a nitroxide spin probe into a cylindrical polyacrylamide gel rod. The nitroxide spin density distribution was imaged at 1.6 GHz in gel cross sections at various time intervals for both homogeneous radial diffusion and inhomogeneous diffusion. A one-dimensional radial diffusion constant was calculated for the nitroxide spin probe, TEMPOL, of 3.7 ± 0.7 × 10 -6 cm 2/s at ambient temperature. The EPR spectrometer, using low-field flat-loop surface coils (H. Nishikawa, H. Fujii, and L. J. Berliner, J. Magn. Reson.62, 79 (1985)), showed minimal dielectric or magnetic losses in sensitity for electrolyte vs nondielectric samples.

  10. Positive affect and psychobiological processes relevant to health.

    PubMed

    Steptoe, Andrew; Dockray, Samantha; Wardle, Jane

    2009-12-01

    Empirical evidence suggests that there are marked associations between positive psychological states and health outcomes, including reduced cardiovascular disease risk and increased resistance to infection. These observations have stimulated the investigation of behavioral and biological processes that might mediate protective effects. Evidence linking positive affect with health behaviors has been mixed, though recent cross-cultural research has documented associations with exercising regularly, not smoking, and prudent diet. At the biological level, cortisol output has been consistently shown to be lower among individuals reporting positive affect, and favorable associations with heart rate, blood pressure, and inflammatory markers such as interleukin-6 have also been described. Importantly, these relationships are independent of negative affect and depressed mood, suggesting that positive affect may have distinctive biological correlates that can benefit health. At the same time, positive affect is associated with protective psychosocial factors such as greater social connectedness, perceived social support, optimism, and preference for adaptive coping responses. Positive affect may be part of a broader profile of psychosocial resilience that reduces risk of adverse physical health outcomes.

  11. Detailed Kinetic Modeling of Processes Relevant To Fusion Energy

    NASA Astrophysics Data System (ADS)

    Mehl, Marco; Armstrong, Michael; Zaug, Joseph; Crowhurst, Jonathan; Radousky, Harry; Stavrou, Elissaios

    2016-10-01

    Carbon based materials have been proposed as candidates for the fabrication of plasma-facing components in the design of fusion energy devices. Although these components are not supposed to be in direct contact with the core fusion plasma, plasma instabilities and the harsh environment they are exposed to can cause the degradation of plasma-exposed components and the transfer of contaminants into the plasma followed by deposition of byproducts. In order to investigate the chemistry involved in these processes and to assist the development of models suitable to understand the long term consequences of the carbon ablation/deposition cycle, an inductively coupled plasma flow reactor (ICPFR) has been developed. The ICPFR allows the atomization of carbon containing precursors to high temperatures (in the order of 10000K) and the characterization of the gas and solid species formed downsteam from the plasma source through spectroscopic techniques. In parallel to the experimental analysis a comprehensive set of fluid dynamic and detailed kinetic simulations are used to analyze the data. The combination of these two approaches resulted in a validated and comprehensive chemical model for the formation of carbon deposits in carbon contaminated cooling plasmas. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Self-esteem modulates the latency of P2 component in implicit self-relevant processing.

    PubMed

    Yang, Juan; Qi, Mingming; Guan, Lili

    2014-03-01

    Previous study has shown that the latency of P2 component was more prolonged in processing self-relevant words compared to processing non-self-relevant words. However, the prolonged P2 latency may index the self-relevance of the words, the valence of the words, or an interaction of the two. The present study aimed to (1) further clarify the specific psychological significance of the prolonged P2 latency in implicit self-processing and (2) investigate the potential association between self-esteem and the latency of P2 in processing implicit self-relevant information. Nineteen participants were examined using event-related potentials (ERPs) technology. They were exposed to positive and negative words and were asked to make a judgment about the color of each word. For the data analysis, words were grouped individually according to their degree of self-relevance (low vs. high) for each participant. Results showed that the latency of P2 was more prolonged in processing the negative-high self-relevant words compared to processing the positive-high self-relevant words. Also, self-esteem was negatively correlated with the P2 latency in processing negative-high self-relevant words. Overall, the results of the present study suggested that levels of self-esteem might modulate neural correlates of self-referential processing.

  13. Laboratory studies of heterogeneous processes relevant to Mars

    NASA Astrophysics Data System (ADS)

    Gough, Raina V.

    Heterogeneous (gas-surface) processes may play an important role in both the atmospheric and surface chemistry of Mars. Atmospheric species may be affected by the chemistry and physical properties of the planetary surface and the surface material may be affected by the components and properties of the atmosphere. In this thesis, several laboratory studies are described which experimentally investigate two types of atmosphere-surface systems likely to exist on Mars. First, experiments were performed to better understand the spatial and temporal variability of atmospheric methane (CH4) on Mars. Reported CH4 plumes in the atmosphere of Mars are difficult to explain using known chemical or physical processes. The observations imply a strong, present-day source and also a rapid yet unknown CH4 sink. We have investigated the potential role of mineral dust in CH4 variability. First, using a Knudsen cell capable of simulating Martian temperature and pressure conditions, we have studied the adsorption of CH4 to a Martian mineral analog as a function of temperature. An uptake coefficient was determined and then applied to the Martian surface-atmosphere system. Our results suggest that adsorption to soil grains could possibly affect the CH4 mixing ratio on a seasonal time scale especially at mid-latitude regions. Additionally, chemical oxidation of CH4 by oxidants thought to exist in the Martian regolith was studied. The Viking mission in the 1970's found Martian soil was able to oxidize complex organic compounds to CO 2. The identity of the oxidant is unknown, but has been proposed to be either hydrogen peroxide or perchlorate salts. We used a gas chromatograph to determine if simulated Mars soil containing these oxidants was able to oxidize CH4 to CO2. However, no CH4 was oxidized within the detection limit of the instrument and only an upper limit reaction coefficient could be reported. Even these upper limit values suggest CH 4 could not be removed from the Martian

  14. Teaching Igneous Geology in Physical Geography: Some Recommendations.

    ERIC Educational Resources Information Center

    Powell, William E.

    1982-01-01

    The most common igneous minerals and their diagnostic properties, which the author considers the most significant and pragmatic aspect of igneous geology for physical geography students, are discussed. The nature of igneous geology is also examined. (RM)

  15. Geochemical characteristics of igneous rocks associated with epithermal mineral deposits—A review

    USGS Publications Warehouse

    du Bray, Edward A.

    2017-01-01

    Newly synthesized data indicate that the geochemistry of igneous rocks associated with epithermal mineral deposits varies extensively and continuously from subalkaline basaltic to rhyolitic compositions. Trace element and isotopic data for these rocks are consistent with subduction-related magmatism and suggest that the primary source magmas were generated by partial melting of the mantle-wedge above subducting oceanic slabs. Broad geochemical and petrographic diversity of individual igneous rock units associated with epithermal deposits indicate that the associated magmas evolved by open-system processes. Following migration to shallow crustal reservoirs, these magmas evolved by assimilation, recharge, and partial homogenization; these processes contribute to arc magmatism worldwide.Although epithermal deposits with the largest Au and Ag production are associated with felsic to intermediate composition igneous rocks, demonstrable relationships between magmas having any particular composition and epithermal deposit genesis are completely absent because the composition of igneous rock units associated with epithermal deposits ranges from basalt to rhyolite. Consequently, igneous rock compositions do not constitute effective exploration criteria with respect to identification of terranes prospective for epithermal deposit formation. However, the close spatial and temporal association of igneous rocks and epithermal deposits does suggest a mutual genetic relationship. Igneous systems likely contribute heat and some of the fluids and metals involved in epithermal deposit formation. Accordingly, deposit formation requires optimization of source metal contents, appropriate fluid compositions and characteristics, structural features conducive to hydrothermal fluid flow and confinement, and receptive host rocks, but not magmas with special compositional characteristics.

  16. 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…

  17. 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.

  18. 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.

  19. Functional magnetic resonance imaging adaptation reveals the cortical networks for processing grasp-relevant object properties.

    PubMed

    Monaco, Simona; Chen, Ying; Medendorp, W P; Crawford, J D; Fiehler, Katja; Henriques, Denise Y P

    2014-06-01

    Grasping behaviors require the selection of grasp-relevant object dimensions, independent of overall object size. Previous neuroimaging studies found that the intraparietal cortex processes object size, but it is unknown whether the graspable dimension (i.e., grasp axis between selected points on the object) or the overall size of objects triggers activation in that region. We used functional magnetic resonance imaging adaptation to investigate human brain areas involved in processing the grasp-relevant dimension of real 3-dimensional objects in grasping and viewing tasks. Trials consisted of 2 sequential stimuli in which the object's grasp-relevant dimension, its global size, or both were novel or repeated. We found that calcarine and extrastriate visual areas adapted to object size regardless of the grasp-relevant dimension during viewing tasks. In contrast, the superior parietal occipital cortex (SPOC) and lateral occipital complex of the left hemisphere adapted to the grasp-relevant dimension regardless of object size and task. Finally, the dorsal premotor cortex adapted to the grasp-relevant dimension in grasping, but not in viewing, tasks, suggesting that motor processing was complete at this stage. Taken together, our results provide a complete cortical circuit for progressive transformation of general object properties into grasp-related responses.

  20. 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.

  1. 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).

  2. Drama advertisements: moderating effects of self-relevance on the relations among empathy, information processing, and attitudes.

    PubMed

    Chebat, Jean-Charles; Vercollier, Sarah Drissi; Gélinas-Chebat, Claire

    2003-06-01

    The effects of drama versus lecture format in public service advertisements are studied in a 2 (format) x 2 (malaria vs AIDS) factorial design. Two structural equation models are built (one for each level of self-relevance), showing two distinct patterns. In both low and high self-relevant situations, empathy plays a key role. Under low self-relevance conditions, drama enhances information processing through empathy. Under high self-relevant conditions, the advertisement format has neither significant cognitive or empathetic effects. The information processing generated by the highly relevant topic affects viewers' empathy, which in turn affects the attitude the advertisement and the behavioral intent. As predicted by the Elaboration Likelihood Model, the advertisement format enhances the attitudes and information processing mostly under low self-relevant conditions. Under low self-relevant conditions, empathy enhances information processing while under high self-relevance, the converse relation holds.

  3. Geochemical Behavior of Selenium in Igneous Systems

    NASA Astrophysics Data System (ADS)

    Jenner, F. E.; Mavrogenes, J. A.; Arculus, R. J.; O'Neill, H. S.

    2008-12-01

    Selenium (Se) is generally assumed to behave much like sulfur (S) in igneous systems. However, it is unclear how valid this assumption is considering that so little is known about the geochemical behaviour of Se. Constraining the range in Se and S concentrations of mantle-derived magmas is important to studies of: core segregation; the composition of late-accreted material; collisional erosion models; processes of mantle melting in various tectonic environments; and recycling of lithospheric components into the mantle, to mention only a few. Previous estimates of the S/Se of primitive and depleted mantle assume that S-Se are similar to Zr-Hf and Nb-Ta in their geochemical coherence, and that S/Se of the Earth's mantle is chondritic (Palme and O"Neill 2003 and references therein). Due to the low abundances of Se in mantle-derived rocks and the lack of calibration materials for routine analysis (i.e. NIST 612), this assumption remains unchallenged. Using a combination of SHRIMP, electron probe, and LA-ICP-MS techniques the concentration of Se in NIST 612 and BCR-2G was obtained to permit rapid in situ LA-ICP-MS analysis of Se concentrations in volcanic glasses. We have obtained Se, S, major and comprehensive trace element data for volcanic glasses from a global range of tectonic settings (mid-ocean ridges, ocean island, island arc and back-arc basins) to improve understanding of the behaviour of Se during igneous processes (e.g. partial melting, fractional crystallisation, and volatile phase separation). Analysis of a range of mid-ocean ridge glasses shows that Se behaves as an incompatible element, but is decoupled from S as the S/Se extends to values well in excess of the chondritic estimate (i.e. 2528; Palme and O"Neill 2003). During back-arc basin and island-arc magmatism, the abundance, systematics and S/Se are diverse. For example, at a specific MgO content, the absolute abundance of Se varies with depletion of the mantle source. Within back-arc suites derived

  4. Organic protomolecule assembly in igneous minerals.

    PubMed

    Freund, F; Staple, A; Scoville, J

    2001-02-27

    CH stretching bands, nu(CH), 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 -CH(2) units. The nu(CH) bands indicate that H(2)O and CO(2), dissolved in the matrix of these minerals, converted to form H(2) 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 nu(CH) bands to disappear, but annealing at 70 degrees C causes them to reappear within a few days or weeks. Modeling dislocations in MgO suggests that the segregation of C can lead to C(x) chains, x = 4, with the terminal C atoms anchored to the MgO matrix by bonding to two O(-). Allowing H(2) to react with such C(x) chains leads to [O(2)C(CH(2))(2)CO(2)] or similar precipitates. It is suggested that such C(x)--H(y)--O(z) 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Potential Future Igneous Activity at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Cline, M.; Perry, F. V.; Valentine, G. A.; Smistad, E.

    2005-12-01

    Location, timing, and volumes of post-Miocene volcanic activity, along with expert judgement, 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 10-8 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. U.S. 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 10-8 be evaluated. Two consequence scenarios are considered; 1) igneous intrusion-groundwater 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 contents of

  11. 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

  12. 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.

  13. 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.

  14. Petrology of igneous clasts in Northwest Africa 7034: Implications for the petrologic diversity of the martian crust

    NASA Astrophysics Data System (ADS)

    Santos, Alison R.; Agee, Carl B.; McCubbin, Francis M.; Shearer, Charles K.; Burger, Paul V.; Tartèse, Romain; Anand, Mahesh

    2015-05-01

    The martian meteorite Northwest Africa (NWA) 7034 was examined both petrographically and geochemically using several micro-beam techniques including electron probe microanalysis and secondary ion mass spectrometry. We have identified various clast types of igneous, sedimentary, and impact origin that occur within the breccia, and we define a classification scheme for these materials based on our observations, although our primary focus here is on the petrology of the igneous clasts. A number of different igneous clasts are present in this meteorite, and our study revealed the presence of at least four different igneous lithologies (basalt, basaltic andesite, trachyandesite, and an Fe, Ti, and P (FTP) rich lithology). These lithologies do not appear to be related by simple igneous processes such as fractional crystallization, indicating NWA 7034 is a polymict breccia that contains samples from several different igneous sources. The basalt lithologies are a good match for measured rock compositions from the martian surface, however more exotic lithologies (e.g., trachyandesite and FTP lithologies) show this meteorite contains previously unsampled rock types from Mars. These new rock types provide evidence for a much greater variety of igneous rocks within the martian crust than previously revealed by martian meteorites, and supports recent rover observations of lithologic diversity across the martian surface. Furthermore, the ancient ages for the lithologic components in NWA 7034 indicate Mars developed this lithologic diversity in the early stages of crust formation.

  15. 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.

  16. Interrelation of attention and prediction in visual processing: Effects of task-relevance and stimulus probability.

    PubMed

    Marzecová, Anna; Widmann, Andreas; SanMiguel, Iria; Kotz, Sonja A; Schröger, Erich

    2017-03-09

    The potentially interactive influence of attention and prediction was investigated by measuring event-related potentials (ERPs) in a spatial cueing task with attention (task-relevant) and prediction (probabilistic) cues. We identified distinct processing stages of this interactive influence. Firstly, in line with the attentional gain hypothesis, a larger amplitude response of the contralateral N1, and Nd1 for attended gratings was observed. Secondly, conforming to the attenuation-by-prediction hypothesis, a smaller negativity in the time window directly following the peak of the N1 component for predicted compared to unpredicted gratings was observed. In line with the hypothesis that attention and prediction interface, unpredicted/unattended stimuli elicited a larger negativity at central-parietal sites, presumably reflecting an increased prediction error signal. Thirdly, larger P3 responses to unpredicted stimuli pointed to the updating of an internal model. Attention and prediction can be considered as differentiated mechanisms that may interact at different processing stages to optimise perception.

  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. On the relevance of the NPY2-receptor variation for modes of action cascading processes.

    PubMed

    Beste, Christian; Stock, Ann-Kathrin; Epplen, Jörg T; Arning, Larissa

    2014-11-15

    Every day, we encounter situations in which we have to deal with multiple response options. In order not to overstrain response selection resources, we need to cascade the associated task goals. Yet, the neurobiological foundations of these action cascading processes are largely unknown. Aiming at determining the possible relevance of the neuropeptide Y Y2 receptor for action cascading processes, this study investigates a functional promoter variation (rs2234759) in the neuropeptide Y Y2 receptor gene (NPY2R). 176 healthy subjects completed a stop-change paradigm. Applying mathematical constraints to the obtained behavioral data allowed for a classification of the action cascading processing mode on a serial to parallel continuum. Neurophysiological data (EEG) were analyzed along this mathematical constraint. The behavioral data show that the Y2-receptor high expression G allele is associated with a less efficient mode of action cascading where different task goals are activated in parallel. The neurophysiological data indicate that this effect is based on modulations at the response selection stage but not on changes in the preceding attentional selection processes. Analyses show that the interrelation between behavioral and neurophysiological data is mediated by genotype effects. At the level of response selection, genotype effects are associated with activity changes in the anterior cingulate cortex (ACC). Changes in the reliability of neural synchronization processes in the theta frequency band are also related to these effects. Possibly, these Y2-receptor-related effects emerge from the receptor's strong interrelation with the dopamine system.

  19. 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.

  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. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. Geochemical microanalysis: The link between textural and geochemical characterization of igneous rocks

    NASA Astrophysics Data System (ADS)

    Kent, A. J.

    2003-12-01

    In this presentation I will review recent advances in microanalytical techniques that allow us to directly couple textural and geochemical information to the study of igneous rocks, particularly with respect to the analysis of silicate melt inclusions. Textural examination has long been a mainstay of the classification and petrologic study of igneous materials. The advent of the electron microprobe over 50 years ago allowed textural and geochemical observations to be coupled at small spatial scales and directly related to the physical and chemical conditions of formation and subsequent melt evolution. This resulted in a revolution in the petrological investigation and understanding of igneous rocks that continues today. Recent advances in geochemical microanalysis techniques are providing exciting access to new geochemical information at smaller and smaller spatial scales. These are enabling measurement of the abundances, and in some cases isotopic compositions, of a range of elements in correspondingly smaller sample volumes. A case in point is the study of silicate melt inclusions. Although melt inclusions have been recognized and studied for over a century, there has been a recent surge in interest directly tied to development of techniques capable of performing in-situ analysis of trace element and volatile components at small spatial scales. Melt inclusions allow direct sampling of melts present during crystal formation, and are particularly useful for relating crystal textures and compositions to those of their source melts. Chemical compositions of melt inclusions reveal the diversity of igneous compositions present in igneous systems, and may be combined with textural observations to constrain a wide range of igneous processes, including degassing, assimilation, fractional crystallization and mixing.

  9. Magmatic Evolution of the Skye Igneous Center, Western Scotland

    NASA Astrophysics Data System (ADS)

    Fowler, S. J.; Bohrson, W. A.; Spera, F. J.

    2003-12-01

    Geochemically complex igneous suites are the result of interplay between deep and crustal-level processes. Quantitatively modeling the contribution that crustal-level processes such as magma recharge, crustal assimilation, and fractional crystallization have is critical for developing realistic models of how magma transport/storage systems evolve. The Energy-Constrained Recharge, Assimilation, and Fractional Crystallization simulator (EC-RAFC, Spera & Bohrson, 2001, 2002; Bohrson & Spera, 2001, 2003) provides a means to model thermal, compositional, and magma volume data for complex magmatic systems. The Skye igneous center, western Scotland, spanning the period 60.53 +/- 0.08 Ma - 53.5 +/- 0.8 Ma and characterized by a well-documented suite of lavas and intrusive rocks of picritic to granitic composition, is the first natural data set to which the EC-RAFC model has been applied in detail. Based on analysis of published field, stratigraphic, petrographic, and chemical data, we propose that the Skye Tertiary magmatic sequence be divided into four petrogenetically related lineages. EC-RAFC results indicate that each lineage is characterized by a unique parental magma that has undergone distinct episodes of RAFC. Model results, constrained by published data on the nature of the crust beneath Skye, indicate that the character of the assimilant changes upsection, suggesting that the associated magma reservoirs migrated to shallower levels as the magmatic system matured. The magmatic products of each group also record the fingerprint of multiple episodes of magma recharge, where the character of the recharge magma also evolves with time. The image of the magma transport system that emerges is one in which magma is initially intruded at lower crustal levels and undergoes a distinct RAFC episode. Residual magma from this event then migrates to shallower levels, where mid-crustal wallrock is assimilated; recharge magma is characterized by increasingly crustal chemical and

  10. The role of the auditory brainstem in processing musically relevant pitch.

    PubMed

    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.

  11. 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.

  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. Classification scheme for sedimentary and igneous rocks in Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Mangold, N.; Schmidt, M. E.; Fisk, M. R.; Forni, O.; McLennan, S. M.; Ming, D. W.; Sautter, V.; Sumner, D.; Williams, A. J.; Clegg, S. M.; Cousin, A.; Gasnault, O.; Gellert, R.; Grotzinger, J. P.; Wiens, R. C.

    2017-03-01

    Rocks analyzed by the Curiosity rover in Gale crater include a variety of clastic sedimentary rocks and igneous float rocks transported by fluvial and impact processes. To facilitate the discussion of the range of lithologies, we present in this article a petrological classification framework adapting terrestrial classification schemes to Mars compositions (such as Fe abundances typically higher than for comparable lithologies on Earth), to specific Curiosity observations (such as common alkali-rich rocks), and to the capabilities of the rover instruments. Mineralogy was acquired only locally for a few drilled rocks, and so it does not suffice as a systematic classification tool, in contrast to classical terrestrial rock classification. The core of this classification involves (1) the characterization of rock texture as sedimentary, igneous or undefined according to grain/crystal sizes and shapes using imaging from the ChemCam Remote Micro-Imager (RMI), Mars Hand Lens Imager (MAHLI) and Mastcam instruments, and (2) the assignment of geochemical modifiers based on the abundances of Fe, Si, alkali, and S determined by the Alpha Particle X-ray Spectrometer (APXS) and ChemCam instruments. The aims are to help understand Gale crater geology by highlighting the various categories of rocks analyzed by the rover. Several implications are proposed from the cross-comparisons of rocks of various texture and composition, for instance between in place outcrops and float rocks. All outcrops analyzed by the rover are sedimentary; no igneous outcrops have been observed. However, some igneous rocks are clasts in conglomerates, suggesting that part of them are derived from the crater rim. The compositions of in-place sedimentary rocks contrast significantly with the compositions of igneous float rocks. While some of the differences between sedimentary rocks and igneous floats may be related to physical sorting and diagenesis of the sediments, some of the sedimentary rocks (e

  14. Self-esteem modulates dorsal medial prefrontal cortical response to self-positivity bias in implicit self-relevant processing.

    PubMed

    Yang, Juan; Dedovic, Katarina; Guan, Lili; Chen, Yu; Qi, Mingming

    2014-11-01

    Processing self-related material recruits similar neural networks regardless of whether the self-relevance is made explicit or not. However, when considering the neural mechanisms that distinctly underlie cognitive and affective components of self-reflection, it is still unclear whether the same mechanisms are involved when self-reflection is explicit or implicit, and how these mechanisms may be modulated by individual personality traits, such as self-esteem. In the present functional MRI study, 25 participants were exposed to positive and negative words that varied with respect to the degree of self-relevance for each participant; however, the participants were asked to make a judgment about the color of the words. Regions-of-interest analysis showed that medial prefrontal cortex (mPFC) and posterior cingulate cortex were associated with gauging the self-relevance of information. However, no main effect of valence or an interaction effect between self-relevance and valence was observed. Further, positive correlations were observed between levels of self-esteem and response within dorsal mPFC (dmPFC) both in the contrast positive-high in self-relevance trials vs positive-low in self-relevance trials and in the contrast negative-low in self-relevance trials vs positive-low in self-relevance trials. These results suggested that the activation of dmPFC may be particularly associated with the processes of self-positivity bias.

  15. Investigation of SRTM Data for Delineation of Process Relevant Response Units in Different Landscapes

    NASA Astrophysics Data System (ADS)

    Wolf, M.; Pfennig, B.

    2007-12-01

    The concept of this research is justified to the integration of landscape components for hydrological modelling within distributed models. Distributed models are based on homogenous entities which are delineated using landscape parameters such as topography, land use, soil, and geology. In ungauged basins most of these required data are only available on a coarse spatial resolution. In order to by-pass this gap the globally and freely available data from the Shuttle Radar Topography Mission (SRTM) were used to obtain model entities on a finer resolution because this data have an adequate resolution of 30m and 90m. The method relies on the assumption of a strong, process-driven feedback between the topography and further landscape components as well as runoff dynamics. It is expected that the water balance of catchments with insufficient data availability can be estimated using SRTM-based delineations of process-oriented model entities. A main goal is the investigation of the SRTM-data for delineation of process relevant response units (RU) over various scales. In order to correct geometric and radiometric errors the SRTM-data were optimized using several GIS procedures and new algorithms for void filling, vegetation reduction, hydrological oriented filter combinations and stream burning. A new developed sink fill method was implemented with the name LaSA (Landscape based Sink Algorithm). Elimination of sinks should be realized by a landscape-based optimum between filling sinks and carving of flow paths in flow barriers. In result of DEM preparation, hydrological corrected elevation data were available to establish a ruled-based framework for RU-delineation. Numerous topographic indices were applied whereas the index selection was oriented on different relief driven processes. The resulting datasets were analysed by the Cluster Analysis IVHG. Finally, different patterns of process driven RU, combing various topographic indices were delineated for three mesoscale

  16. 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.

  17. 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

    2010-12-02

    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.

  18. 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.

  19. 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.

  20. Access, Relevance, and Control in the Research Process: Lessons From Indian Country

    PubMed Central

    MANSON, SPERO M.; GARROUTTE, EVA; GOINS, R. TURNER; HENDERSON, PATRICIA NEZ

    2017-01-01

    Objective To illustrate successful strategies in working with American Indian (AI) and Alaska Native (AN) communities in aging and health research by emphasizing access, local relevance, and decision-making processes. Methods Case examples of health studies involving older AIs (≥50 years) among Eastern Band Cherokee Indians, a federally recognized reservation; the Cherokee Nation, a rural, nonreservation, tribal jurisdictional service area; and Lakota tribal members living in Rapid City, South Dakota. Results Local review and decision making reflect the unique legal and historical factors underpinning AI sovereignty. Although specific approval procedures vary, there are common expectations across these communities that can be anticipated in conceptualizing, designing, and implementing health research among native elders. Conclusions Most investigators are unprepared to address the demands of health research in AI communities. Community-based participatory research in this setting conflicts with investigators’ desire for academic freedom and scientific independence. Successful collaboration promises to enhance research efficiencies and move findings more quickly to clinical practice. PMID:15448287

  1. Relevance of land surface processes for the prediction of future droughts in mid-latitudes

    NASA Astrophysics Data System (ADS)

    Seneviratne, S. I.; Pal, J. S.; Eltahir, E. A. B.; Schär, C.

    2003-04-01

    The enhanced occurrence of summer droughts in mid-latitudes is generally considered a likely consequence of climate change (e.g. IPCC 2001). However, some of the key studies investigating this issue employed the so-called bucket model for the representation of the land surface hydrology, which, due to its oversimplification, might not account for all processes relevant to this issue. In this study, regional climate simulations are conducted over North America for present and future climate conditions, using a land-surface scheme of intermediate complexity (the Biosphere-Atmosphere Transfer Scheme/BATS) and a simplified version of it mimicking the behaviour of the bucket model. With BATS, the warmer-climate simulations show little to no enhancement of soil drying in the considered region. With the bucket-type formulation, however, a positive feedback loop induces an extreme enhancement of soil drying when drought-like conditions are prevailing. The differing sensitivity of the two parameterizations is ascribed to the more realistic response of plants to drought stress in BATS, which limits evaporation to a minimum when soil moisture gets limited. These results suggest that studies using the bucket model might have overestimated the risk of enhanced drought in the mid latitudes. This calls for a more detailed investigation of the role of vegetation for climate change.

  2. 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.

  3. Legal Terms Used in Reception Order and their Relevance to Judicial Process

    PubMed Central

    Subramanian, Nakkeerar; Ramanathan, Rajkumar; Kumar, Venkatesh Madhan; Chellappan, Dhanabalan Kalingarayan Palayam; Ramasamy, Jeyaprakash

    2016-01-01

    Introduction: Law governs the admission and management of involuntary admissions of mentally ill persons who are admitted under the provisions of the mental health act. The court directs the doctor to take charge of such persons. In the further dealings of such person the medical officer of the psychiatric facility comes across legal terms, which require understanding so that patients could be dealt with properly. Various terms such as accused, under police custody, judicial custody, remand prisoner, or under trial prisoner are used to denote their legal status. It is imperative for the medical officer to understand the nuances in the meanings of these terms. There are many times when the relevant section under which the admission is ordered is not found in the reception order. In these cases the terminology by which the patient is mentioned throws a light on the status of the patient. Towards this aim a study was carried out to assess the awareness and understanding of such terms by the faculty and post- graduates of a tertiary care hospital that deals with the admission and care of such patients. Method: They were administered a questionnaire containing these terms and asked to provide the meaning of these terms. Results: The results showed that nearly half the faculty and students were not having clarity in awareness or understanding of the terms. Discussion: Hence these terms and their meanings were gleaned from various judgments. The proper meaning of these terms and their use in judicial process and their importance is discussed. PMID:27833226

  4. A clinically relevant model of osteoinduction: a process requiring calcium phosphate and BMP/Wnt signalling

    PubMed Central

    Eyckmans, J; Roberts, S J; Schrooten, J; Luyten, F P

    2010-01-01

    Abstract In this study, we investigated a clinically relevant model of in vivo ectopic bone formation utilizing human periosteum derived cells (HPDCs) seeded in a Collagraft™ carrier and explored the mechanisms by which this process is driven. Bone formation occurred after eight weeks when a minimum of one million HPDCs was loaded on Collagraft™ carriers and implanted subcutaneously in NMRI nu/nu mice. De novo bone matrix, mainly secreted by the HPDCs, was found juxta-proximal of the calcium phosphate (CaP) granules suggesting that CaP may have triggered the ‘osteoinductive program’. Indeed, removal of the CaP granules by ethylenediaminetetraacetic acid decalcification prior to cell seeding and implantation resulted in loss of bone formation. In addition, inhibition of endogenous bone morphogenetic protein and Wnt signalling by overexpression of the secreted antagonists Noggin and Frzb, respectively, also abrogated osteoinduction. Proliferation of the engrafted HPDCs was strongly reduced in the decalcified scaffolds or when seeded with adenovirus-Noggin/Frzb transduced HPDCs indicating that cell division of the engrafted HPDCs is required for the direct bone formation cascade. These data suggest that this model of bone formation is similar to that observed during physiological intramembranous bone development and may be of importance when investigating tissue engineering strategies. PMID:19538476

  5. 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.

  6. Large igneous provinces linked to supercontinent assembly

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Santosh, M.; Luo, Zhaohua; Hao, Jinhua

    2015-04-01

    Models for the disruption of supercontinents have considered mantle plumes as potential triggers for continental extension and the formation of large igneous provinces (LIPs). An alternative hypothesis of top-down tectonics links large volcanic eruptions to lithospheric delamination. Here we argue that the formation of several LIPs in Tarim, Yangtze, Lhasa and other terranes on the Eurasian continent was coeval with the assembly of the Pangean supercontinent, in the absence of plumes rising up from the mantle transition zone or super-plumes from the core-mantle boundary. The formation of these LIPs was accompanied by subduction and convergence of continents and micro-continents, with no obvious relation to major continental rifting or mantle plume activity. Our model correlates LIPs with lithospheric extension caused by asthenospheric flow triggered by multiple convergent systems associated with supercontinent formation.

  7. 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/.

  8. 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.

  9. 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

  10. Construction and evolution of igneous bodies: Towards an integrated perspective of crustal magmatism

    NASA Astrophysics Data System (ADS)

    Annen, Catherine; Blundy, Jonathan D.; Leuthold, Julien; Sparks, R. Stephen J.

    2015-08-01

    Field, geochronological and geophysical studies show that many igneous bodies are emplaced incrementally, growing by accretion of successive magma sheets. The existence of melt reservoirs with a size that exceeds one single increment strongly depends on the sheet emplacement rate, whereas the total volumes of magma that accumulate depend on the volumetric magma flux. Integration of geochronological and field data with numerical simulations suggeststhat those rates can vary dramatically over the growth of an igneous body and that magmas accumulate to form melt-rich magma chambers only during episodes of high magma flux. Heat and mass balance considerations and the large volumes of mafic magma required to generate differentiated melts suggest that most crustal differentiation happens in deep hot zones in the lower crust wherein a wide diversity of melts are produced by crystallisation of mafic parents and concomitant partial melting of the crust. Melt composition is further modified during migration, segregation and ascent, and intermediate compositions can be generated when different types of melt mix. Magma fluxes and intrusion geometry play a fundamental role in igneous body evolution. Thus our knowledge of igneous processes depends ultimately on our understanding of the physics that control magma fluxes into the crust, magma emplacement within the crust and magma migration through the crust.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. 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…

  18. 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.

  19. 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.

  20. 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.

  1. Hemispheric processing of differently valenced and self-relevant attachment words in middle-aged married and separated individuals.

    PubMed

    Fussell, Nicola J; Rowe, Angela C; Mohr, Christine

    2012-01-01

    The reliance in experimental psychology on testing undergraduate populations with relatively little life experience, and/or ambiguously valenced stimuli with varying degrees of self-relevance, may have contributed to inconsistent findings in the literature on the valence hypothesis. To control for these potential limitations, the current study assessed lateralised lexical decisions for positive and negative attachment words in 40 middle-aged male and female participants. Self-relevance was manipulated in two ways: by testing currently married compared with previously married individuals and by assessing self-relevance ratings individually for each word. Results replicated a left hemisphere advantage for lexical decisions and a processing advantage of emotional over neutral words but did not support the valence hypothesis. Positive attachment words yielded a processing advantage over neutral words in the right hemisphere, while emotional words (irrespective of valence) yielded a processing advantage over neutral words in the left hemisphere. Both self-relevance manipulations were unrelated to lateralised performance. The role of participant sex and age in emotion processing are discussed as potential modulators of the present findings.

  2. High crystallization temperatures indicated for igneous rocks from tranquillity base.

    PubMed

    Skinner, B J

    1970-01-30

    Complex intergrowths of troilite (FeS) and iron in the igneous rocks from Tranquillity Base contain 8.4 percent native iron by volume. The intergrowths were derived from an initially homogeneous sulfide liquid that separated immiscibly from the magma at 1140 degrees C or above. Textures show that the sulfide liquid formed late in the crystallization and cooling history of the igneous rocks and after the major ilmenite and pyroxene had formed.

  3. 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

  4. 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

  5. Linking attentional processes and conceptual problem solving: visual cues facilitate the automaticity of extracting relevant information from diagrams.

    PubMed

    Rouinfar, Amy; Agra, Elise; Larson, Adam M; Rebello, N Sanjay; Loschky, Lester C

    2014-01-01

    This study investigated links between visual attention processes and conceptual problem solving. This was done by overlaying visual cues on conceptual physics problem diagrams to direct participants' attention to relevant areas to facilitate problem solving. Participants (N = 80) individually worked through four problem sets, each containing a diagram, while their eye movements were recorded. Each diagram contained regions that were relevant to solving the problem correctly and separate regions related to common incorrect responses. Problem sets contained an initial problem, six isomorphic training problems, and a transfer problem. The cued condition saw visual cues overlaid on the training problems. Participants' verbal responses were used to determine their accuracy. This study produced two major findings. First, short duration visual cues which draw attention to solution-relevant information and aid in the organizing and integrating of it, facilitate both immediate problem solving and generalization of that ability to new problems. Thus, visual cues can facilitate re-representing a problem and overcoming impasse, enabling a correct solution. Importantly, these cueing effects on problem solving did not involve the solvers' attention necessarily embodying the solution to the problem, but were instead caused by solvers attending to and integrating relevant information in the problems into a solution path. Second, this study demonstrates that when such cues are used across multiple problems, solvers can automatize the extraction of problem-relevant information extraction. These results suggest that low-level attentional selection processes provide a necessary gateway for relevant information to be used in problem solving, but are generally not sufficient for correct problem solving. Instead, factors that lead a solver to an impasse and to organize and integrate problem information also greatly facilitate arriving at correct solutions.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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…

  13. Petrology of Igneous Clasts in Regolithic Howardite EET 87503

    NASA Technical Reports Server (NTRS)

    Hodges, Z. V.; Mittlefehldt, D. W.

    2017-01-01

    The howardite, eucrite and diogenite (HED) clan of meteorites is widely considered to originate from asteroid 4 Vesta, as a result of a global magma ocean style of differentiation. A global magmatic stage would allow silicate material to be well mixed, destroying any initial heterogeneity that may have been present resulting in the uniformity of eucrite and diogenite delta(exp 17)O, for example. The Fe/Mn ratio of mafic phases in planetary basalts can be diagnostic of different source bodies as this ratio is little-affected by igneous processes, so long as the oxygen and sulphur fugacities are buffered. Here, pyroxene Fe/Mn ratios in mafic clasts in howardite EET 87503 have been determined to further evaluate whether the HED parent asteroid is uniform. Uniformity would suggest that the parent asteroid was subject to homogenization prior to the formation of HED lithologies, likely through an extensive melting phase. Whereas, distinct differences may point towards heterogeneity of the parent body.

  14. Relevant ion time scales for electron impact processes of atoms in dense plasmas

    SciTech Connect

    Murillo, M.S.

    1997-12-31

    In this paper a new model for treating collisional atomic processes has been presented. This model simultaneously and self-consistently treats electron and ion processes. For transitions frequencies above the ion plasma frequency, it is argued that little ion motion occurs although the interaction is still strong; the ion microfield perturbs the atom. The electron impact processes may still be described by a DSF between levels of the perturbed atoms, suggesting the name Microfield Stochastic Model (MSM) for this method. Future work will be directed towards refining some of the approximations used here for application to realistic systems.

  15. Pump-probe spectroscopy in organic semiconductors: monitoring fundamental processes of relevance in optoelectronics.

    PubMed

    Cabanillas-Gonzalez, Juan; Grancini, Giulia; Lanzani, Guglielmo

    2011-12-08

    In this review we highlight the contribution of pump-probe spectroscopy to understand elementary processes taking place in organic based optoelectronic devices. The techniques described in this article span from conventional pump-probe spectroscopy to electromodulated pump-probe and the state-of-the-art confocal pump-probe microscopy. The article is structured according to three fundamental processes (optical gain, charge photogeneration and charge transport) and the contribution of these techniques on them. The combination of these tools opens up new perspectives for assessing the role of short-lived excited states on processes lying underneath organic device operation.

  16. 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

    2016-04-07

    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.

  17. How Body Orientation Affects Concepts of Space, Time and Valence: Functional Relevance of Integrating Sensorimotor Experiences during Word Processing

    PubMed Central

    Ruiz Fernandez, Susana; Bury, Nils-Alexander; Gerjets, Peter; Fischer, Martin H.; Bock, Otmar L.

    2016-01-01

    The aim of the present study was to test the functional relevance of the spatial concepts UP or DOWN for words that use these concepts either literally (space) or metaphorically (time, valence). A functional relevance would imply a symmetrical relationship between the spatial concepts and words related to these concepts, showing that processing words activate the related spatial concepts on one hand, but also that an activation of the concepts will ease the retrieval of a related word on the other. For the latter, the rotation angle of participant’s body position was manipulated either to an upright or a head-down tilted body position to activate the related spatial concept. Afterwards participants produced in a within-subject design previously memorized words of the concepts space, time and valence according to the pace of a metronome. All words were related either to the spatial concept UP or DOWN. The results including Bayesian analyses show (1) a significant interaction between body position and words using the concepts UP and DOWN literally, (2) a marginal significant interaction between body position and temporal words and (3) no effect between body position and valence words. However, post-hoc analyses suggest no difference between experiments. Thus, the authors concluded that integrating sensorimotor experiences is indeed of functional relevance for all three concepts of space, time and valence. However, the strength of this functional relevance depends on how close words are linked to mental concepts representing vertical space. PMID:27812155

  18. 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.

  19. 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".

  20. 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.

  1. 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.

  2. Origin of igneous meteorites and differentiated asteroids

    NASA Astrophysics Data System (ADS)

    Scott, E.; Goldstein, J.; Asphaug, E.; Bottke, W.; Moskovitz, N.; Keil, K.

    2014-07-01

    Introduction: Igneously formed meteorites and asteroids provide major challenges to our understanding of the formation and evolution of the asteroid belt. The numbers and types of differentiated meteorites and non-chondritic asteroids appear to be incompatible with an origin by fragmentation of numerous Vesta-like bodies by hypervelocity impacts in the asteroid belt over 4 Gyr. We lack asteroids and achondrites from the olivine-rich mantles of the parent bodies of the 12 groups of iron meteorites and the ˜70 ungrouped irons, the 2 groups of pallasites and the 4--6 ungrouped pallasites. We lack mantle and core samples from the parent asteroids of the basaltic achondrites that do not come from Vesta, viz., angrites and the ungrouped eucrites like NWA 011 and Ibitira. How could core samples have been extracted from numerous differentiated bodies when Vesta's basaltic crust was preserved? Where is the missing Psyche family of differentiated asteroids including the complementary mantle and crustal asteroids [1]? Why are meteorites derived from far more differentiated parent bodies than chondritic parent bodies even though C and S class chondritic asteroids dominate the asteroid belt? New paradigm. Our studies of meteorites, impact modeling, and dynamical studies suggest a new paradigm in which differentiated asteroids accreted at 1--2 au less than 2 Myr after CAI formation [2]. They were rapidly melted by 26Al and disrupted by hit-and-run impacts [3] while still molten or semi-molten when planetary embryos were accreting. Metallic Fe-Ni bodies derived from core material cooled rapidly with little or no silicate insulation less than 4 Myr after CAI formation [4]. Fragments of differentiated planetesimals were subsequently tossed into the asteroid belt. Meteorite evidence for early disruption of differentiated asteroids. If iron meteorites were samples of Fe-Ni cores of bodies that cooled slowly inside silicate mantles over ˜50--100 Myr, irons from each core would have

  3. 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.

  4. 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

  5. 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.

  6. Role of Sirt1 during the ageing process: relevance to protection of synapses in the brain.

    PubMed

    Godoy, Juan A; Zolezzi, Juan M; Braidy, Nady; Inestrosa, Nibaldo C

    2014-12-01

    Ageing is a stochastic process associated with a progressive decline in physiological functions which predispose to the pathogenesis of several neurodegenerative diseases. The intrinsic complexity of ageing remains a significant challenge to understand the cause of this natural phenomenon. At the molecular level, ageing is thought to be characterized by the accumulation of chronic oxidative damage to lipids, proteins and nucleic acids caused by free radicals. Increased oxidative stress and misfolded protein formations, combined with impaired compensatory mechanisms, may promote neurodegenerative disorders with age. Nutritional modulation through calorie restriction has been shown to be effective as an anti-ageing factor, promoting longevity and protecting against neurodegenerative pathology in yeast, nematodes and murine models. Calorie restriction increases the intracellular levels of the essential pyridine nucleotide, nicotinamide adenine dinucleotide (NAD(+)), a co-substrate for the sirtuin 1 (Sirt1, silent mating-type information regulator 2 homolog 1) activity and a cofactor for oxidative phosphorylation and ATP synthesis. Promotion of intracellular NAD(+) anabolism is speculated to induce neuroprotective effects against amyloid-β-peptide (Aβ) toxicity in some models for Alzheimer's disease (AD). The NAD(+)-dependent histone deacetylase, Sirt1, has been implicated in the ageing process. Sirt1 serves as a deacetylase for numerous proteins involved in several cellular pathways, including stress response and apoptosis, and plays a protective role in neurodegenerative disorders, such as AD.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Ventilation Relevant Contaminants of Concern in Commercial Buildings Screening Process and Results

    SciTech Connect

    Parthasarathy, Srinandini; McKone, Thomas E.; Apte, Michael G.

    2011-04-29

    This report summarizes the screening procedure and its results for selecting contaminants of concern (COC), whose concentrations are affected by ventilation in commercial buildings. Many pollutants comprising criteria pollutants, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and biological contaminants are found in commercial buildings. In this report, we focus primarily on identifying potential volatile organic COC, which are impacted by ventilation. In the future we plan to extend this effort to inorganic gases and particles. Our screening considers compounds detected frequently in indoor air and compares the concentrations to health-guidelines and thresholds. However, given the range of buildings under consideration, the contaminant sources and their concentrations will vary depending on the activity and use of the buildings. We used a literature review to identify a large list of chemicals found in commercial-building indoor air. The VOCs selected were subject to a two stage screening process, and the compounds of greater interest are included in priority List A. Other VOCs that have been detected in commercial buildings are included in priority List B. The compounds in List B, were further classified into groups B1, B2, B3, B4 in order of decreasing interest.

  13. 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.

  14. Relevance of electron spin dissipative processes to dynamic nuclear polarization via thermal mixing.

    PubMed

    Serra, Sonia Colombo; Filibian, Marta; Carretta, Pietro; Rosso, Alberto; Tedoldi, Fabio

    2014-01-14

    The available theoretical approaches aiming at describing Dynamic Nuclear spin Polarization (DNP) in solutions containing molecules of biomedical interest and paramagnetic centers are not able to model the behaviour observed upon varying the concentration of trityl radicals or the polarization enhancement caused by moderate addition of gadolinium complexes. In this manuscript, we first show experimentally that the nuclear steady state polarization reached in solutions of pyruvic acid with 15 mM trityl radicals is substantially independent on the average internuclear distance. This evidences a leading role of electron (over nuclear) spin relaxation processes in determining the ultimate performances of DNP. Accordingly, we have devised a variant of the Thermal Mixing model for inhomogenously broadened electron resonance lines which includes a relaxation term describing the exchange of magnetic anisotropy energy of the electron spin system with the lattice. Thanks to this additional term, the dependence of the nuclear polarization on the electron concentration can be properly accounted for. Moreover, the model predicts a strong increase of the final polarization upon shortening the electron spin-lattice relaxation time, providing a possible explanation for the effect of gadolinium doping.

  15. 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.

  16. Experiments and analysis of drainage displacement processes relevant to carbon dioxide injection.

    PubMed

    Aryana, Saman A; Kovscek, Anthony R

    2012-12-01

    The motivation for this work is a dramatically improved understanding of the fluid mechanics of drainage processes with applications such as CO_{2} storage in saline aquifers and water-alternating-gas injection as an enhanced oil recovery method. In this paper we present in situ distributions of wetting and nonwetting fluids obtained during core-scale two-phase immiscible drainage experiments. The ratio of the viscosity of the resident fluid to that of the invading fluid varies across a range of 0.43 to 150. Saturation distributions observed during dynamic displacement experiments are surprisingly smooth and do not display only one or a few dominant fingers, contrary to the indications of the current literature. The analysis of the saturation distribution using the fractal dimensions of the dynamic three-dimensional saturation distributions suggests that the constitutive relationships for porous media, namely, the relative permeability functions, are history dependent. Accordingly, it is suggested that the nonlinear, unstable flow regime is the regime where efforts to improve physical understanding must be focused.

  17. 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.

  18. ELECTRON IRRADIATION AND THERMAL PROCESSING OF MIXED-ICES OF POTENTIAL RELEVANCE TO JUPITER TROJAN ASTEROIDS

    SciTech Connect

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

    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 H{sub 2}S. We perform a set of experiments to explore the hypothesis advanced by Wong and Brown that links the color bimodality in Jupiter's Trojans to the presence of H{sub 2}S in the surface of their precursors. Non-thermal (10 keV electron irradiation) and thermally driven chemistry of CH{sub 3}OH–NH{sub 3}–H{sub 2}O (“without H{sub 2}S”) and H{sub 2}S–CH{sub 3}OH–NH{sub 3}–H{sub 2}O (“with H{sub 2}S”) 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 H{sub 2}S” mixture experiment shows a rapid consumption of H{sub 2}S molecules and production of OCS molecules after a few hours of irradiation. The heating of the irradiated “with H{sub 2}S” mixture to temperatures above 120 K leads to the appearance of new infrared bands that we provisionally assign to SO{sub 2}and 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.

  19. 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.

  20. 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

  1. Mind Over Magma: The Story of Igneous Petrology

    NASA Astrophysics Data System (ADS)

    Snyder, Don

    2004-01-01

    In the centuries that enquiring minds have studied and theorized about igneous rocks, much progress has been made, both in accumulating observations and in developing theories. Yet, writing a history of this progress is a daunting undertaking. The volume of the literature is vast and in multiple languages; the various lines of inquiry are diverse and complex; and the nomenclature is sometimes abstruse. On top of these challenges, many of its principal issues have yet to find a definitive consensus. With the exception of a few topical studies, historians of science have virtually avoided the subject. In Mind Over Magma: The Story of Igneous Petrology, Davis Young has taken on the challenge of writing a comprehensive survey of the study of igneous rocks, and the result has been a remarkable book of meticulous scholarship. Igneous petrology is a vast subject, and it is not obvious how best to organize its history. Young takes a topical approach, generally grouping together various studies by either the problem being investigated or the method of attack. These topics span the earliest times to the present, with an emphasis on recurring themes, such as the causes of magmatic diversity and the origins of the granitic rocks. The range of topics includes most of the subjects central to the field over its history. As much as is practical, topics are discussed in chronological order, and along the way, the reader is treated to biographical sketches of many of the key contributors. This organization proves effective in dealing with the multitude of concepts.

  2. 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.

  3. 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.

  4. Survey of Large, Igneous-Textured Inclusions in Ordinary Chondrites

    NASA Astrophysics Data System (ADS)

    Armstrong, K.; Ruzicka, A. M.

    2013-12-01

    Ordinary (O) chondrites are a class of primitive stony meteorites, and as a group comprise our most abundant samples of early solar system materials. Unique to O chondrites are igneous-textured inclusions up to 4 cm in diameter; about an order of magnitude larger than the much more abundant chondrules. These inclusions are almost always highly depleted in metal and sulfide relative to their host meteorite, but but otherwise have diverse characteristics. They exhibit a large range of textures, mineralogies, and bulk compositions, suggesting a variety of formation processes. They all crystallized from large melt volumes, the origins of which are poorly understood. Models proposed for their formation include (1) shock melting of ordinary chondrites with an associated loss of metal and sulfide; (2) melting of vapor-fractionated condensate mixture; (3) chondrule formation involving a larger melt production volume than typical for chondrules; and (4) igneous differentiation occurring within planetesimals sampled by ordinary chondrite parent bodies. Polished thin sections of inclusions from several O-chondrites have been examined with optical light microscopy (OLM) using a Leica DM 2500 petrographic microscope. Petrographic data such as texture, grain sizes and shapes were collected for the inclusions and their hosts in order to facilitate comparisons. Texturally, the inclusions were determined to fall into one of three distinct textural categories: porphyritic, fine granular, and skeletal. Mean grain sizes are on the order of 100 um for both microporphyritic and fine granular inclusions, with microporphyritic inclusions showing a much wider range of grain sizes. The largest grains in the microporphyritic inclusions are on average ~0.25 mm, with the grains of the mesostasis <100 microns. Skeletal olivine textures are defined as being dominated by crystals that are an order of magnitude longer across one direction than the other (e.g., 1 mm x 100 um). Five inclusions have

  5. 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

  6. 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

  7. Thermal, high pressure, and electric field processing effects on plant cell membrane integrity and relevance to fruit and vegetable quality.

    PubMed

    Gonzalez, Maria E; Barrett, Diane M

    2010-09-01

    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).

  8. 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.

  9. Towards a comprehensive classification of igneous rocks and magmas

    NASA Astrophysics Data System (ADS)

    Middlemost, Eric A. K.

    1991-08-01

    The IUGS Subcommission on the Systematics of Igneous Rocks has recently published an excellent book on the classification of these rocks. This event has shifted the vexed question of classification towards the top of the agenda in igneous petrology. Over the years the Subcommission has used many different criteria to establish the positions of the boundaries between the various common igneous rocks. It now has to adopt a holistic approach and develop a comprehensive, coherent classification that is purged of all the minor anomalies that arise between the various classifications that it has approved. It is appreciated that the Subcommission's classification was never intended to have any genetic implications; however, it is suggested that an ideal classification should he presented in such a way that it is able to group rocks into an order that directs attention to petrogenetic relationships between individual rocks and larger groups of rocks. Unfortunately, many of the Subcommission's definitions are Earth chauvinistic; for example, igneous rocks are defined as being those rocks that solidified from a molten state either within or on the surface of the Earth. Nowhere in the book is it acknowledged that during the past 20 years, while the Subcommission has been framing its many recommendations, a whole new science of planetary petrology has subsumed classical petrology. In any new edition of the book, the Subcommission should acknowledge that rocks are essentially the solid materials of which planets, natural satellites and other broadly similar cosmic bodies are made. The Subcommission should also explicitly recognise that igneous rocks can be divided into either a main sequence of essentially common rocks or a number of supplementary clans of special rocks that evolved outside the main sequence. It is hoped that in the near future the Subcommission will rescind its recommendation that the TAS classification should be regarded as an adjunct to its more traditional

  10. 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.

  11. 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.

  12. 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.

  13. Log-ratio transformed major element based multidimensional classification for altered High-Mg igneous rocks

    NASA Astrophysics Data System (ADS)

    Verma, Surendra P.; Rivera-Gómez, M. Abdelaly; Díaz-González, Lorena; Quiroz-Ruiz, Alfredo

    2016-12-01

    A new multidimensional classification scheme consistent with the chemical classification of the International Union of Geological Sciences (IUGS) is proposed for the nomenclature of High-Mg altered rocks. Our procedure is based on an extensive database of major element (SiO2, TiO2, Al2O3, Fe2O3t, MnO, MgO, CaO, Na2O, K2O, and P2O5) compositions of a total of 33,868 (920 High-Mg and 32,948 "Common") relatively fresh igneous rock samples. The database consisting of these multinormally distributed samples in terms of their isometric log-ratios was used to propose a set of 11 discriminant functions and 6 diagrams to facilitate High-Mg rock classification. The multinormality required by linear discriminant and canonical analysis was ascertained by a new computer program DOMuDaF. One multidimensional function can distinguish the High-Mg and Common igneous rocks with high percent success values of about 86.4% and 98.9%, respectively. Similarly, from 10 discriminant functions the High-Mg rocks can also be classified as one of the four rock types (komatiite, meimechite, picrite, and boninite), with high success values of about 88%-100%. Satisfactory functioning of this new classification scheme was confirmed by seven independent tests. Five further case studies involving application to highly altered rocks illustrate the usefulness of our proposal. A computer program HMgClaMSys was written to efficiently apply the proposed classification scheme, which will be available for online processing of igneous rock compositional data. Monte Carlo simulation modeling and mass-balance computations confirmed the robustness of our classification with respect to analytical errors and postemplacement compositional changes.

  14. Geochemistry of the Kalkarindji Magmas: Insights into the Source of the Oldest Phanerozoic Large Igneous Province

    NASA Astrophysics Data System (ADS)

    Ware, B. D.; Jourdan, F.; Hodges, K.; Tessalina, S.; Chiaradia, M.; Evins, L.; Gole, M.

    2014-12-01

    The Kalkarindji continental flood basalt province (CFBP) of northern Australia is the oldest Phanerozoic large igneous province (LIP) in the world. The extent of this Middle Cambrian LIP has been estimated to at least 2.1 x 106 km2 with exposures in Western Australia, Northern Territory, Queensland, and South Australia. The research into Kalkarindji is still in its infancy with only a handful of studies published. The rocks of the Kalkarindji province occur as lava flows, sills, dykes, and volcanic tuffs. Kalkarindji has been linked to an extinction event at the Early-Middle Cambrian boundary. The Kalkarindji province displays Low-Ti values and high SiO2 values compared to other large igneous provinces, enriched 87Sr/86Sr values, and low 187Os/188Os. This project presents a large data set of new geochemical analyses of the various constituents of the Kalkarindji CFBP. Source mixing calculations, assimilation and fractionation models, coupled with Monte Carlo simulations were carried out to understand the petrogenesis of the province. The trace element and 87Sr/86Sr values indicate a contribution of enriched crustal-like material into the source region; however, the Os values fall into typical mantle ranges. These geochemical patterns suggest that the mantle source(s) of the Kalkarindji CFBP has been directly enriched at some stage of history, before the emplacement of the province. This study will provide further insights into the magma source and origin processes needed to create one of the world's largest and oldest Phanerozoic large igneous provinces.

  15. 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.

  16. A Comparison of Microbial Communities from Deep Igneous Crust

    NASA Astrophysics Data System (ADS)

    Smith, A. R.; Flores, G. E.; Fisk, M. R.; Colwell, F. S.; Thurber, A. R.; Mason, O. U.; Popa, R.

    2013-12-01

    Recent investigations of life in Earth's crust have revealed common themes in organism function, taxonomy, and diversity. Capacities for hydrogen oxidation, carbon fixation, methanogenesis and methanotrophy, iron and sulfur metabolisms, and hydrocarbon degradation often predominate in deep life communities, and crustal mineralogy has been hypothesized as a driving force for determining deep life community assemblages. Recently, we found that minerals characteristic of the igneous crust harbored unique communities when incubated in the Juan de Fuca Ridge flank borehole IODP 1301A. Here we present attached mineral biofilm morphologies and a comparison of our mineral communities to those from a variety of locations, contamination states, and igneous crustal or mineralogical types. We found that differences in borehole mineral communities were reflected in biofilm morphologies. Olivine biofilms were thick, carbon-rich films with embedded cells of uniform size and shape and often contained secondary minerals. Encrusted cells, spherical and rod-shaped cells, and tubes were indicative of glass surfaces. We also found that the attached communities from incubated borehole minerals were taxonomically more similar to native, attached communities from marine and continental crust than to communities from the aquifer water that seeded it. Our findings further support the hypothesis that mineralogy selects for microbial communities that have distinct phylogenetic, morphological, and potentially functional, signatures. This has important implications for resolving ecosystem function and microbial distributions in igneous crust, the largest deep habitat on Earth.

  17. 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.

  18. 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.

  19. ON THE FORMATION OF AMIDE POLYMERS VIA CARBONYL–AMINO GROUP LINKAGES IN ENERGETICALLY PROCESSED ICES OF ASTROPHYSICAL RELEVANCE

    SciTech Connect

    Förstel, Marko; Maksyutenko, Pavlo; Jones, Brant M.; Kaiser, Ralf I.; Sun, Bing J.; Lee, Huan C.; Chang, Agnes H. H. E-mail: hhchang@mail.ndhu.edu.tw

    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.

  20. 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

  1. Characterization of Arctic Highly Magnetic Domains - the Geophysical Expression of Inferred Large Igneous Province(s)

    NASA Astrophysics Data System (ADS)

    Saltus, R. W.; Oakey, G.; Miller, E. L.; Jackson, R.

    2012-12-01

    The magnetic anomalies of the high arctic are dominated by a large domain (1000 x 1700 km; the High Arctic Magnetic High, HAMH) consisting of numerous high-amplitude magnetic high ridges with a complex set of orientations and by other smaller, but still fundamentally highly magnetic, domains. The magnetic potential anomaly field (also known as pseudogravity) of the HAMH shows a single large intensity high and underscores the crustal-scale thickness of this geophysical feature (which also forms a prominent anomaly on satellite magnetic maps). The seafloor morphology of this region includes the complex linear trends of the Alpha and Mendeleev ridges, but the magnetic expression of this domain extends beyond the complex bathymetry to include areas where Canada Basin sediments have covered the complex basement topography. The calculated magnetic effect of the bathymetric ridges matches some of the observed magnetic anomalies, but not others. We have analyzed and modeled the distinctive HAMH and other smaller magnetic high domains to generate estimates of their volume and to characterize the directionality of their component features. Complimentary processing and modeling of high arctic gravity anomalies allows characterization of the density component of these geophysical features. Spatially, the HAMH encompasses the Alpha and Mendeleev "ridges," that are considered to represent a major mafic igneous province. The term "Alpha-Mendeleev Large Igneous Province" is given to a domain mapped by tracing magnetic anomalies in a recent map published by AAPG (Grantz and others, 2009). On this map the province is described as "alkali basalt with ages between 120 and 90 Ma". New seismic and bathymetric data, collected as part of on-going research efforts for definition of extended continental shelf, are revealing new details about the Alpha ridge. One interesting development is the possible identification of a supervolcano that may represent a major locus of igneous activity. In

  2. The growth of large mafic intrusions: Comparing Niquelândia and Ivrea igneous complexes

    NASA Astrophysics Data System (ADS)

    Correia, Ciro Teixeira; Sinigoi, Silvano; Girardi, Vicente Antonio Vitorio; Mazzucchelli, Maurizio; Tassinari, Colombo Celso Gaeta; Giovanardi, Tommaso

    2012-12-01

    The Niquelândia Complex, Brazil, is one of the world's largest mafic-ultramafic plutonic complexes. Like the Mafic Complex of the Ivrea-Verbano Zone, it is affected by a pervasive high-T foliation and shows hypersolidus deformation structures, contains significant inclusions of country-rock paragneiss, and is subdivided into a Lower and an Upper Complex. In this paper, we present new SHRIMP U-Pb zircon ages that provide compelling evidence that the Upper and the Lower Niquelândia Complexes formed during the same igneous event at ca. 790 Ma. Coexistence of syn-magmatic and high-T subsolidus deformation structures indicates that both complexes grew incrementally as large crystal mush bodies which were continuously stretched while fed by pulses of fresh magma. Syn-magmatic recrystallization during this deformation resulted in textures and structures which, although appearing metamorphic, are not ascribable to post-magmatic metamorphic event(s), but are instead characteristic of the growth process in huge and deep mafic intrusions such as both the Niquelândia and Ivrea Complexes. Melting of incorporated country-rock paragneiss continued producing hybrid rocks during the last, vanishing stages of magmatic crystallization. This resulted in the formation of minor, late-stage hybrid rocks, whose presence obscures the record of the main processes of interaction between mantle magmas and crustal components, which may be active at the peak of the igneous events and lead to the generation of eruptible hybrid magmas.

  3. 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

  4. Physiological and anthropometric characteristics of young soccer players according to their playing position: relevance for the selection process.

    PubMed

    Gil, Susana M; Gil, Javier; Ruiz, Fátima; Irazusta, Amaia; Irazusta, Jon

    2007-05-01

    The aim of this study was to establish the anthropometric and physiological profiles of young nonelite soccer players according to their playing position, and to determine their relevance for the selection process. Two hundred forty-one male soccer players who were members of the Getxo Arenas Club (Bizkaia) participated in this study. Players, age 17.31 (+/- 2.64) years, range 14-21 years, were classified into the following groups: forwards (n = 56), midfielders (n = 79), defenders (n = 77), and goalkeepers (n = 29). Anthropometric variables of participants (height, weight, body mass index, 6 skinfolds, 4 diameters, and 3 perimeters) were measured. Also, their somatotype and body composition (weights and percentages of fat, bone, and muscle) were calculated. Participants performed the Astrand test to estimate their absolute and relative VO2max, an endurance test, sprint tests (30 meters flat and 30 meters with 10 cones) and 3 jump tests (squat jump, counter movement jump and drop jump). Forwards were the leanest, presenting the highest percentage of muscle. They were the best performers in all the physiological tests, including endurance, velocity, agility, and power. In contrast, goalkeepers were found to be the tallest and the heaviest players. They also had the largest fat skinfolds and the highest fat percentage, but their aerobic capacity was the lowest. In the selection process, agility and the jump tests were the most discriminating for forwards. In contrast, agility, height, and endurance were the key factors for midfielders. The defenders group was characterized by a lower quantity of fat. Thus, we may conclude that anthropometric and physiological differences exist among soccer players who play in different positions. These differences fit with their different workload in a game. Therefore, training programs should include specific sessions for each positional role.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. PVA in Igneous Petrology: The Rosetta Stone for Testing Mixing and Fractionation Models

    NASA Astrophysics Data System (ADS)

    Vogel, T. A.; Ehrlich, R.

    2006-05-01

    One of the major goals of igneous petrology is to evaluate the relative contributions of fractional crystallization and magma mixing (or assimilation) that produce the chemical variations within related igneous units (plutons, sills and dikes, ash-flow tuffs, lavas etc). Mixing and fractional crystallization have often been evaluated by selecting a few variables (major elements, trace elements, isotopes) and modeling the trends. EC-AFC models have been developed to include energy constraints along with selected trace elements and isotopes. Polytopic Vector Analysis (PVA) is a technique that uses all of the chemical variations (major elements and trace elements) in all the samples to determine: (1) the number of end member compositions present in the system, (2) the chemical composition of each end member, and (3) the relative contribution of each end member in each sample from the igneous unit. Each sample in the dataset is described as the sum of some fraction of each end member; therefore each sample is uniquely described by a specific amount of each of the end members. Each end member is defined in the same non negative units as the sample values. Graphical analysis of the output allows the recognition of trends either due to crystal fraction or mixing of separate magma batches (assimilation), as samples form discrete clusters or trends with different variations in end member proportions. Mixing of discrete magma batches is immediately apparent, as samples representing mixed magmas plot between the parent magmas. PVA has been used successfully to identify end members in aqueous geochemistry and petroleum. However, even though it was originally developed in part by igneous petrologists, it has not been thoroughly tested on petrologic problems. In order to evaluate PVA, we selected three igneous units in which fractionation and mixing processes had been identified: (1) glasses from Kilauea Iki drilling, which are unquestionably due to crystal fractionation; (2

  10. Igneous rocks of the West Sakhalin Terrane of Sakhalin Island

    NASA Astrophysics Data System (ADS)

    Grannik, V. M.

    2016-10-01

    It has been determined that the Rozhdestvenka Formation of the West Sakhalin Terrane composed of Late Mesozoic igneous rocks is a fragment of the accretionary prism of the Rebun-Kabato-Moneron-Samarga island-arc system. Volcanic eruptions, as well as destruction of the Rebun-Kabato-Moneron-Samarga island-arc and the East Sikhote-Alin volcano plutonic marginal continental belt, were the sources of pyroclastic and clastic material entering the sedimentary basin, where the Pobedinsk and Krasnoyarka suites of the West Sakhalin Terrane were formed.

  11. 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

  12. Magnetostriction and palæomagnetism of igneous rocks

    USGS Publications Warehouse

    Graham, John W.; Buddington, A.F.; Balsley, James 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. Development and field application of a littoral processes monitoring system for examination of the relevant time scales of sediment suspension processes

    NASA Astrophysics Data System (ADS)

    Thosteson, Eric David

    A microcontroller-based system of oceanographic instrumentation providing a comprehensive set of measurements relevant to sediment transport processes has been developed. Analysis of the data provided by the system yields time series of vertical profiles of mean sediment size and concentration, horizontal profiles of bedform geometry, and single location measurements of flow velocity, pressure, turbidity, and water temperature. Details of the system architecture, including capabilities provided by both hardware and software contained within the system are given. An improved method for the determination of suspended sediment size and concentration from the system's acoustic backscatter intensity measurements is presented. By retaining the size dependence throughout the derivation for an explicit solution for concentration, a new explicit solution to the acoustic backscatter equation results. This new concentration solution improves the technique for determining median sediment size by incorporating sediment attenuation in the calculation. Because this new technique relies on the minimization of the variance in concentration as determined by different frequency transducers, the previous technique of pairing transducers of different frequencies is replaced by a technique making use of any number of different frequency transducers. The new size/concentration inversion technique is tested using both simulated and laboratory data. Numerical precision is shown to be the only source of error with the use of simulated data. Laboratory tests result in less than 20% error in the determination of both concentration and size over a range of nearly one meter. Finally, suspended sediment concentration data from the nearshore region obtained from an experiment performed in Duck, North Carolina, are examined to find the relevant time scales of sediment suspension. In this location, low frequency forcing mechanisms are as significant in suspending sediment as the incident-band wave

  18. 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.

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

    PubMed

    Nozette, S; Lewis, J S

    1982-04-09

    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.

  20. 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.

  1. Evaporatic-source model for igneous-related Fe oxide (REE-Cu-Au-U) mineralization

    SciTech Connect

    Barton, M.D.; Johnson, D.A.

    1996-03-01

    We propose that many igneous-related Fe oxide-rich (REE-Cu-Au-U-bearing) deposits form by hydrothermal processes involving evaporitic ligand sources, either coeval salars or older evaporites. These deposits are abundant in both Phanerozoic and Proterozoic extensional continental and continent-margin settings. They commonly form in global arid zones, but they also occur where magmatism is superimposed upon older evaporites. Magmatic compositions exert only second-order control, mainly on alteration mineralogy and on element abundances. Hot S-poor brines generated by interaction with evaporitic materials are consistent with geologic settings and help rationalize the distinctive element enrichments (siderophile, lithophile) and hydrothermal alteration (sodic, locally alkaline) found in these systems. This model contrasts with immiscible oxide melt and magmatic-hydrothermal origins commonly proposed for these deposits, although all three mechanisms can occur. 31 refs., 3 figs., 1 tab.

  2. 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.

  3. Cognitive Processing about Classroom-Relevant Contexts: Teachers' Attention to and Utilization of Girls' Body Size, Ethnicity, Attractiveness, and Facial Affect

    ERIC Educational Resources Information Center

    Wang, Shirley S.; Treat, Teresa A.; Brownell, Kelly D.

    2008-01-01

    This study examines 2 aspects of cognitive processing in person perception--attention and decision making--in classroom-relevant contexts. Teachers completed 2 implicit, performance-based tasks that characterized attention to and utilization of 4 student characteristics of interest: ethnicity, facial affect, body size, and attractiveness. Stimuli…

  4. 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

  5. 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.

  6. 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)

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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).

  13. Metasedimentary and igneous xenoliths from Tallante (Betic Cordillera, Spain): Inferences on crust-mantle interactions and clues for post-collisional volcanism magma sources

    NASA Astrophysics Data System (ADS)

    Bianchini, Gianluca; Braga, Roberto; Langone, Antonio; Natali, Claudio; Tiepolo, Massimo

    2015-04-01

    The deep seated xenolith association exhumed in the Pliocenic volcano of Tallante (Betic Cordillera, Spain) includes protogranular mantle peridotites, felsic (metasedimentary) crustal rocks, as well as cumulus igneous rocks such as norites and amphibole (± phlogopite)-clinopyroxenites. The whole xenolith suite equilibrated at the same pressure (0.7-0.9 GPa) representing the local crust-mantle boundary (MOHO) characterized by extreme lithological heterogeneity. This heterogeneity resulted from orogenic processes that induced the juxtaposition of crustal rocks (variably depleted in fusible components) within mantle domains including metasomes, as it is commonly observed in orogenic mantle massifs of the Mediterranean area. In this contribution, we report new mineral compositions of igneous parageneses recorded in these xenoliths, and we present Sr-Nd isotope data on both igneous and metasedimentary xenoliths that integrate those from the literature. Sr-Nd isotopes coherently indicate a restitic character of the metasedimentary xenoliths, which according to model ages were affected by partial melting in Paleozoic times. Sr-Nd isotopic errorchrons on the igneous xenoliths, on the other hand, qualitatively indicate Tertiary ages, which are corroborated by U-Pb zircon datings of one norite xenolith and two composite xenoliths having zircon-bearing norite veinlets. The new data are discussed proposing that MOHO lithologies of Tallante could provide significant source compositions for the genesis of the Neogene volcanics of the Betic area, which included calcalkaline lavas as well as more potassic products such as lamproites.

  14. 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

  15. 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.

  16. Pliocene-Pleistocene diatoms in Paleozoic and Mesozoic sedimentary and igneous rocks from Antarctica: A Sirius problem solved

    NASA Astrophysics Data System (ADS)

    Burckle, Lloyd H.; Potter, Noel, Jr.

    1996-03-01

    There are two competing scenarios on the behavior of the East Antarctic ice sheet during the late Tertiary. In one scenario, the ice sheet was very dynamic and underwent major drawdown and renewal as late as the Pliocene. In the other, the ice sheet was relatively stable during the late Neogene. The presence of marine diatoms in Sirius Group sedimentary rocks in East Antarctica is at the center of the disagreement. One side regards the diatoms as the major piece of evidence to support the drawdown and renewal hypothesis and infers that they were introduced into the Sirius during renewed glaciation of East Antarctica; others suggest that these diatoms were likely introduced into the Sirius by atmospheric (largely eolian) processes. We propose a simple test of the eolian hypothesis. If diatoms were introduced into the Sirius by eolian processes, then they should also be present in older (Paleozoic and Mesozoic) sedimentary and igneous rocks. Samples from two units of the Beacon Supergroup (Devonian to Jurassic) from Beacon Valley, East Antarctica, were analyzed: the Beacon Heights Orthoquartzite (Devonian) and the Feather Conglomerate (Permian-Triassic). Also examined was sediment found in cracks of Paleozoic and Mesozoic (Devonian to Cretaceous) igneous rocks from Marie Byrd Land, West Antarctica. Largely Pliocene-Pleistocene planktonic marine diatoms were found in all sample sets. Because neither Beacon Supergroup sedimentary rocks nor igneous rocks from Marie Byrd Land are Pliocene-Pleistocene in age, such findings strongly suggest that diatoms were introduced into them by eolian processes. This same scenario can be applied to Sirius Group sedimentary rocks.

  17. Granodiorite Pluton Formation at the Mid-Cenozoic Never Summer Igneous Complex, North-Central Colorado

    NASA Astrophysics Data System (ADS)

    Jacob, K. H.; Farmer, G.

    2012-12-01

    Field observations, major- and trace-element geochemistry, and Sr and Nd isotopic data were used to assess the petrogenesis of epizonal intrusive rocks and related volcanic rocks from the ~28 Ma Never Summer igneous complex in north-central Colorado. Intrusive igneous rocks at this igneous center consist of an older granodiorite pluton (the Mt Richthofen stock, MRS) that is intruded by the granitic Mt. Cumulus stock. The latter has a uniform bulk composition equivalent to that of high silica rhyolite (~77 wt % SiO2, ɛNd(T) ~ -6). Whole rock studies of the MRS reveal that it is compositionally zoned (55-67 wt % SiO2,ɛNd(T) -0.5 to -5.7, 87Sr/86Sr(T) 0.7049 to 0.7119), with the lowest wt % SiO2 and highest ɛNd(T) occurring along the western margin of the pluton. Field observations, combined with the observed compositional variations, suggest that the pluton was originally a shallowly intruded (< 2 km), ~1 km thick sill that was vertically zoned from a mafic base to more felsic roof. The entire pluton has been tilted ~25 degrees to the west after emplacement. Given the lack of obvious wall-rock assimilation at the level of pluton emplacement, the isotopic variations in the pluton most likely reflect differences in the isotopic compositions of melts from which the pluton was assembled. Obvious field evidence exists for underplating of the developing pluton by mafic, high ɛNd (T) (>-2) melts and illustrates that mafic magmas were present in the uppermost crust and likely participated in pluton formation. The higher wt % SiO2 and lower ɛNd(T) portions of the MRS, however, could not have been derived directly from the mafic magmas in any closed system process. One option is that the MRS ultimately represents the product of mixing of >70 wt % SiO2 melts (+ crystals), analogous to the melts from which the Mt. Cumulus stock crystallized, and underplating mafic magma. This model implies that two primary magmas types, high silica rhyolite and basalt/basaltic andesite

  18. Trace Elements in Igneous Quartz: a new Petrogenetic Tool for the Study of Granite Pegmatite Genesis

    NASA Astrophysics Data System (ADS)

    Larsen, R. B.; Larsen, R. B.; Flem, B.; Henderson, I.; Ihlen, P. M.; Ihlen, P. M.; Lahaye, Y.; Malvik, T.; Prestvik, T.

    2001-12-01

    The trace-element chemistry of quartz is rarely, if ever, considered when evaluating the origin and evolution of silica over-saturated igneous rocks. Analytical obstacles have efficiently prevented in-depth studies of the trace-element chemistry of quartz because the most interesting elements are present at the sub-ppm level and because mineral separation of quartz for traditional solution analysis is a time-consuming process. Also, igneous quartz may contain both fluid and solid inclusions that are difficult to identify during handpicking and may influence the analytical results significantly. However, in the present study we utilised in situ Laser Ablation of quartz specimens with direct introduction of the ablated material in to a double focusing sector field, ICP-MS instrument, and we developed a method that is fine-tuned for the analysis of trace elements in quartz (Flem et al., Chemical Geology, in press). Among the elements covered by the method we have focussed on substitutional trace-elements replacing Si4+ (e.g. Ti, Ge, Al, Fe and P) or elements that represent charge compensators that are accommodated in lattice vacancies or in structural channels (e.g. Li, B, K, Ca, Be). Elements analysed at low, medium and high resolutions include Li, B, Be, Al, Mn, Ge, Rb, Sr, Ba, Pb, Th, Mg, P, Ti, Ca, Cr, Fe and K. 29Si or 30Si, were used as internal standards. In the present study we evaluate the chemical evolution of quartz by comparing with the chemistry of co-existing alkali-feldspar, for which the compositional changes during igneous evolution is well known from the literature. The study includes 75 strongly zoned gadolinite-type REE-Nb-Ta rich chamber pegmatites from two major Neoproterozoic pegmatite fields in SE-Norway. Analysis of alkali-feldspar for major and accessory elements including the REE shows that the pegmatites were formed from progressively more evolved liquids through extreme fractionation of primitive granitic melts. The total concentration of

  19. 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…

  20. 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

  1. 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.

  2. 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

  3. Effects of task-relevant incentives on the electrophysiological correlates of error processing in major depressive disorder.

    PubMed

    Holmes, Avram J; Pizzagalli, Diego A

    2010-03-01

    Major depressive disorder (MDD) is associated with action-monitoring dysfunction-particularly, disrupted error processing. Whether such dysregulation is further modulated by task incentives is largely unknown. The goal of this study was to investigate possible dysfunctions in error processing in MDD as a function of varying task incentives and clinical profile. To this end, we recorded the error-related negativity (ERN) and error positivity (Pe) in 18 MDD participants and 18 healthy controls during a Stroop task that intermixed no-incentive and reward trials. Relative to controls, MDD participants showed (1) larger ERN irrespective of task incentives, and (2) reduced Pe during reward (but not no-incentive) trials. Moreover, among MDD participants, Pe amplitudes were negatively correlated with depression severity and clinical symptoms. The present findings highlight distinct effects of task incentives on electrophysiological components of error processing and are interpreted within current theories of action monitoring and incentive processing in depression.

  4. Antioxidant potential and health relevant functionality of traditionally processed Cassia hirsuta L. seeds: an Indian underutilized food legume.

    PubMed

    Vadivel, Vellingiri; Nandety, Aruna; Biesalski, Hans Konrad

    2011-09-01

    The methanolic extract of Cassia hirsuta L. seed materials, an underutilized food legume collected from India, was analyzed for antioxidant activity and health relevant functionality. The methanolic extract of raw seeds contained a total free phenolic content of 15.82 ± 1.69 g catechin equivalent/100 g extract DM. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1,446 mmol Fe[II]/mg extract), inhibition of ß-carotene degradation (48.81%) and scavenging activity against DPPH (64.40%) and superoxide (43.78%) radicals were exhibited by the raw samples. Further, 83.11% of α-amylase and 62.79% of α-glucosidase enzyme inhibition characteristics under in vitro starch digestion bioassay were also recorded. Sprouting + oil-frying caused an apparent increase on the total free phenolic content and a significant improvement in the antioxidant and free radical scavenging capacity of methanolic extract of C. hirsuta seeds, while soaking + cooking as well as open-pan roasting treatments showed diminishing effects. The analysis of the phenolic profile revealed the presence of gallic acid, p-coumaric acid and (+)-catechin in the methanolic extract of these seeds.

  5. Hawai'i and Gale Crater: A Mars Analogue Study of Igneous, Sedimentary, Weathering, and Alteration Trends in Geochemistry

    NASA Technical Reports Server (NTRS)

    Berger, J. A.; Flemming, R. L.; Schmidt, M. E.; Gellert, R.; Morris, R. V.; Ming, D. W.

    2017-01-01

    Sedimentary rocks in Gale Crater on Mars indicate a varied provenance with a range of alteration and weathering [1, 2]. Geochemical trends identified in basaltic and alkalic sedimentary rocks by the Alpha Particle X-ray Spectrometer (APXS) on the Mars rover Curiosity represent a complex interplay of igneous, sedimentary, weathering, and alteration processes. Assessing the relative importance of these processes is challenging with unknown compositions for parent sediment sources and with the constraints provided by Curiosity's instruments. We therefore look to Mars analogues on Earth where higher-resolution analyses and geologic context can constrain interpretations of Gale Crater geochemical observations. We selected Maunakea (AKA Mauna Kea) and Kohala volcanoes, Hawai'i, for an analogue study because they are capped by post-shield transitional basalts and alkalic lavas (hawaiites, mugearites) with compositions similar to Gale Crater [1, 3]. Our aim was to characterize Hawaiian geochemical trends associated with igneous processes, sediment transport, weathering, and alteration. Here, we present initial results and discuss implications for selected trends observed by APXS in Gale Crater.

  6. 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.

  7. 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.

  8. 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.

  9. 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…

  10. 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.

  11. 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.

  12. 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

  13. Cross sections for proton-induced reactions on Pd isotopes at energies relevant for the γ process

    NASA Astrophysics Data System (ADS)

    Dillmann, I.; Coquard, L.; Domingo-Pardo, C.; Käppeler, F.; Marganiec, J.; Uberseder, E.; Giesen, U.; Heiske, A.; Feinberg, G.; Hentschel, D.; Hilpp, S.; Leiste, H.; Rauscher, T.; Thielemann, F.-K.

    2011-07-01

    Proton-activation reactions on natural and enriched palladium samples were investigated via the activation technique in the energy range of Ep=2.75-9 MeV, close to the upper end of the respective Gamow window of the γ process. We have determined cross sections for 102Pd(p,γ)103Ag, 104Pd(p,γ)105Ag, and 105Pd(p,n)105Ag, as well as partial cross sections of 104Pd(p,n)104Agg, 105Pd(p,γ)106Agm, 106Pd(p,n)106Agm, and 110Pd(p,n)110Agm with uncertainties between 3% and 15% for constraining theoretical Hauser-Feshbach rates and for direct use in γ-process calculations.

  14. 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.

  15. Decreasing predictability of visual motion enhances feed-forward processing in visual cortex when stimuli are behaviorally relevant.

    PubMed

    Kellermann, Thilo; Scholle, Ruben; Schneider, Frank; Habel, Ute

    2017-03-01

    Recent views of information processing in the (human) brain emphasize the hierarchical structure of the central nervous system, which is assumed to form the basis of a functional hierarchy. Hierarchical predictive processing refers to the notion that higher levels try to predict activity in lower areas, while lower levels transmit a prediction error up the hierarchy whenever the predictions fail. The present study aims at testing hypothetical modulatory effects of unpredictable visual motion on forward connectivities within the visual cortex. Functional magnetic resonance imaging was acquired from 35 healthy volunteers while viewing a moving ball under three different levels of predictability. In two different runs subjects were asked to attend to direction changes in the ball's motion, where a button-press was required in one of these runs only. Dynamic causal modeling was applied to a network comprising V1, V5 and posterior parietal cortex in the right hemisphere. The winning model of a Bayesian model selection indicated an enhanced strength in the forward connection from V1 to V5 with decreasing predictability for the run requiring motor response. These results support the notion of hierarchical predictive processing in the sense of an augmented bottom-up transmission of prediction error with increasing uncertainty about motion direction. This finding may be of importance for promoting our understanding of trait characteristics in psychiatric disorders, as an increased forward propagation of prediction error is assumed to underlie schizophrenia and may be observable at early stages of the disease.

  16. The effect of diabetes-associated autoantigens on cell processes in human PBMCs and their relevance to autoimmune diabetes development.

    PubMed

    Vcelakova, Jana; Blatny, Radek; Halbhuber, Zbynek; Kolar, Michal; Neuwirth, Ales; Petruzelkova, Lenka; Ulmannova, Tereza; Kolouskova, Stanislava; Sumnik, Zdenek; Pithova, Pavlina; Krivjanska, Maria; Filipp, Dominik; Stechova, Katerina

    2013-01-01

    Type 1 Diabetes (T1D) is considered to be a T-helper- (Th-) 1 autoimmune disease; however, T1D pathogenesis likely involves many factors, and sufficient tools for autoreactive T cell detection for the study of this disease are currently lacking. In this study, using gene expression microarrays, we analysed the effect of diabetes-associated autoantigens on peripheral blood mononuclear cells (PBMCs) with the purpose of identifying (pre)diabetes-associated cell processes. Twelve patients with recent onset T1D, 18 first-degree relatives of the TD1 patients (DRL; 9/18 autoantibody positive), and 13 healthy controls (DV) were tested. PBMCs from these individuals were stimulated with a cocktail of diabetes-associated autoantigens (proinsulin, IA-2, and GAD65-derived peptides). After 72 hours, gene expression was evaluated by high-density gene microarray. The greatest number of functional differences was observed between relatives and controls (69 pathways), from which 15% of the pathways belonged to "immune response-related" processes. In the T1D versus controls comparison, more pathways (24%) were classified as "immune response-related." Important pathways that were identified using data from the T1D versus controls comparison were pathways involving antigen presentation by MHCII, the activation of Th17 and Th22 responses, and cytoskeleton rearrangement-related processes. Genes involved in Th17 and TGF-beta cascades may represent novel, promising (pre)diabetes biomarkers.

  17. 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}.

  18. 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.

  19. Cross sections for proton-induced reactions on Pd isotopes at energies relevant for the {gamma} process

    SciTech Connect

    Dillmann, I.; Coquard, L.; Domingo-Pardo, C.; Kaeppeler, F.; Marganiec, J.; Uberseder, E.; Giesen, U.; Heiske, A.; Feinberg, G.; Hentschel, D.; Hilpp, S.; Leiste, H.; Rauscher, T.; Thielemann, F.-K.

    2011-07-15

    Proton-activation reactions on natural and enriched palladium samples were investigated via the activation technique in the energy range of E{sub p}=2.75-9 MeV, close to the upper end of the respective Gamow window of the {gamma} process. We have determined cross sections for {sup 102}Pd(p, {gamma}){sup 103}Ag, {sup 104}Pd(p, {gamma}){sup 105}Ag, and {sup 105}Pd(p, n){sup 105}Ag, as well as partial cross sections of {sup 104}Pd(p, n){sup 104}Ag{sup g}, {sup 105}Pd(p, {gamma}){sup 106}Ag{sup m}, {sup 106}Pd(p, n){sup 106}Ag{sup m}, and {sup 110}Pd(p, n){sup 110}Ag{sup m} with uncertainties between 3% and 15% for constraining theoretical Hauser-Feshbach rates and for direct use in {gamma}-process calculations.

  20. Principles of applied experimental igneous petrology: A comment on “Experimental constraints on the Skaergaard liquid line of descent” by Thy, Lesher, Nielsen, and Brooks, 2006, Lithos 92: 154 180

    NASA Astrophysics Data System (ADS)

    Morse, S. A.

    2008-10-01

    The foremost principles of experimental igneous petrology applied to natural rocks are here considered to be the following. First, only the mineral assemblages found at or near the experimental liquidus are relevant to fractional crystallization. Subliquidus assemblages of the same bulk composition can have little relevance to this process, owing to the closed system of the experiment. Second, in a closed system the natural mineral assemblages define the intensive parameters of T, P, and the activities of all components, including oxygen, which must constrain the experimental investigation. Extensive (mass-dependent) parameters do not define the compositions of the evolving liquids, which are solely controlled by successive liquidus phase assemblages. Third, the bulk compositions (rocks or mixtures) chosen for study must be able to yield at the liquidus the mineral compositions found in the natural occurrence. The study under discussion fails in all three of these desiderata. Subliquidus products of equilibrium crystallization and their masses were used to infer a differentiation history. Intensive parameters were constrained to an arbitrary choice of the FMQ buffer. Finally, the bulk compositions chosen for experiment can be shown beforehand (and as in the listed results) to yield olivine and plagioclase compositions far more refractory than in any known rock of the target intrusion.

  1. Recycling cellulases for cellulosic ethanol production at industrial relevant conditions: potential and temperature dependency at high solid processes.

    PubMed

    Lindedam, Jane; Haven, Mai Østergaard; Chylenski, Piotr; Jørgensen, Henning; Felby, Claus

    2013-11-01

    Different versions of two commercial cellulases were tested for their recyclability of enzymatic activity at high dry matter processes (12% or 25% DM). Recyclability was assessed by measuring remaining enzyme activity in fermentation broth and the ability of enzymes to hydrolyse fresh, pretreated wheat straw. Industrial conditions were used to study the impact of hydrolysis temperature (40 or 50°C) and residence time on recyclability. Enzyme recycling at 12% DM indicated that hydrolysis at 50°C, though ideal for ethanol yield, should be kept short or carried out at lower temperature to preserve enzymatic activity. Best results for enzyme recycling at 25% DM was 59% and 41% of original enzyme load for a Celluclast:Novozyme188 mixture and a modern cellulase preparation, respectively. However, issues with stability of enzymes and their strong adsorption to residual solids still pose a challenge for applicable methods in enzyme recycling.

  2. 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.

  3. 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.

  4. 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

    2011-09-14

    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.

  5. 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

  6. 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.

  7. 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

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

    PubMed

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

    2014-05-01

    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.

  9. Human Processing of Behaviorally Relevant and Irrelevant Absence of Expected Rewards: A High-Resolution ERP Study

    PubMed Central

    Nahum, Louis; Gabriel, Damien; Schnider, Armin

    2011-01-01

    Acute lesions of the posterior medial orbitofrontal cortex (OFC) in humans may induce a state of reality confusion marked by confabulation, disorientation, and currently inappropriate actions. This clinical state is strongly associated with an inability to abandon previously valid anticipations, that is, extinction capacity. In healthy subjects, the filtering of memories according to their relation with ongoing reality is associated with activity in posterior medial OFC (area 13) and electrophysiologically expressed at 220–300 ms. These observations indicate that the human OFC also functions as a generic reality monitoring system. For this function, it is presumably more important for the OFC to evaluate the current behavioral appropriateness of anticipations rather than their hedonic value. In the present study, we put this hypothesis to the test. Participants performed a reversal learning task with intermittent absence of reward delivery. High-density evoked potential analysis showed that the omission of expected reward induced a specific electrocortical response in trials signaling the necessity to abandon the hitherto reward predicting choice, but not when omission of reward had no such connotation. This processing difference occurred at 200–300 ms. Source estimation using inverse solution analysis indicated that it emanated from the posterior medial OFC. We suggest that the human brain uses this signal from the OFC to keep thought and behavior in phase with reality. PMID:21298049

  10. 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

  11. Human processing of behaviorally relevant and irrelevant absence of expected rewards: a high-resolution ERP study.

    PubMed

    Nahum, Louis; Gabriel, Damien; Schnider, Armin

    2011-01-27

    Acute lesions of the posterior medial orbitofrontal cortex (OFC) in humans may induce a state of reality confusion marked by confabulation, disorientation, and currently inappropriate actions. This clinical state is strongly associated with an inability to abandon previously valid anticipations, that is, extinction capacity. In healthy subjects, the filtering of memories according to their relation with ongoing reality is associated with activity in posterior medial OFC (area 13) and electrophysiologically expressed at 220-300 ms. These observations indicate that the human OFC also functions as a generic reality monitoring system. For this function, it is presumably more important for the OFC to evaluate the current behavioral appropriateness of anticipations rather than their hedonic value. In the present study, we put this hypothesis to the test. Participants performed a reversal learning task with intermittent absence of reward delivery. High-density evoked potential analysis showed that the omission of expected reward induced a specific electrocortical response in trials signaling the necessity to abandon the hitherto reward predicting choice, but not when omission of reward had no such connotation. This processing difference occurred at 200-300 ms. Source estimation using inverse solution analysis indicated that it emanated from the posterior medial OFC. We suggest that the human brain uses this signal from the OFC to keep thought and behavior in phase with reality.

  12. 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.

  13. New insights into Pseudomonas fluorescens alginate biosynthesis relevant for the establishment of an efficient production process for microbial alginates.

    PubMed

    Maleki, Susan; Mærk, Mali; Hrudikova, Radka; Valla, Svein; Ertesvåg, Helga

    2017-07-25

    Alginate denotes a family of linear polysaccharides with a wide range of industrial and pharmaceutical applications. Presently, all commercially available alginates are manufactured from brown algae. However, bacterial alginates have advantages with regard to compositional homogeneity and reproducibility. In order to be able to design bacterial strains that are better suited for industrial alginate production, defining limiting factors for alginate biosynthesis is of vital importance. Our group has been studying alginate biosynthesis in Pseudomonas fluorescens using several complementary approaches. Alginate is synthesised and transported out of the cell by a multiprotein complex spanning from the inner to the outer membrane. We have developed an immunogold labelling procedure in which the porin AlgE, as a part of this alginate factory, could be detected by transmission electron microscopy. No time-dependent correlation between the number of such factories on the cell surface and alginate production level was found in alginate-producing strains. Alginate biosynthesis competes with the central carbon metabolism for the key metabolite fructose 6-phosphate. In P. fluorescens, glucose, fructose and glycerol, are metabolised via the Entner-Doudoroff and pentose phosphate pathways. Mutational analysis revealed that disruption of the glucose 6-phosphate dehydrogenase gene zwf-1 resulted in increased alginate production when glycerol was used as carbon source. Furthermore, alginate-producing P. fluorescens strains cultivated on glucose experience acid stress due to the simultaneous production of alginate and gluconate. The combined results from our studies strongly indicate that the availability of fructose 6-phosphate and energy requires more attention in further research aimed at the development of an optimised alginate production process.

  14. 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.

  15. Spectral and Kinetic Properties of Radical Cations Derived from Oxoisoaporphines: Relevance to Electron-Transfer Processes Involving Phytoalexins.

    PubMed

    De la Fuente, Julio R; Kciuk, Gabriel; Aliaga, Christian; Bobrowski, Krzysztof

    2014-05-16

    The thermally induced intermolecular electron transfer reaction in acetonitrile between the tetracyanoethylene (TCNE), a π-electron acceptor with a large electron affinity, and six oxoisoaporphines (2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 5-methoxy-2,3-dihydro-7H-dibenzo[de,h]quinolin-7-one, 1-azabenzo[de]anthracen-7-one, 5-methoxy-1-azabenzo[de]anthracen-7-one, 7H-benzo[e]perimidin-7-one, and 2-methyl-7h-benzo[e]perimidin-7-one) is reported. Spectral and kinetic characteristics are presented for radical cations derived from these six oxoisoaporphines either generated by a thermal reaction or generated radiolytically in argon-saturated 1,2-dichloroethane, oxygen-saturated acetone, and acetonitrile. The radical cations of oxoisoaporphines are insensitive to oxygen and are mostly characterized by absorption maxima of their most intense bands located at λmax = 400-410 nm, except of the radical cations derived from 2,3-dihydrooxoisoaporphines. For the latter compounds, the absorption maxima of the most intense absorption bands are located at λmax = 290-295 nm. Their locations are independent of the presence of functional groups and the solvents used. They are formed in bimolecular processes with pseudo-first-order rate constants ranging from 2.1 × 10(5) to 1.5 × 10(6) s(-1) (in solutions containing 10(-4) M of the substrate), depending on the derivative and the solvent used. They are stable either when formed via the electron-transfer reaction with TCNE or when generated in isolation in pulse radiolysis of Ar-saturated 1,2-dichloroethane. In acetone and acetonitrile they decay predominantly by first-order kinetics with the first-order rate constants ranging from 2.3 × 10(4) to 5.1 × 10(4) s(-1). Formation of dimeric radical cations for all of the oxoisoaporphines studied was observed in acetonitrile solutions, and for azaoxoisoaporphines also in acetone solutions. The experimental spectra show a reasonably good agreement with the ZINDO/S semiempirical

  16. 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.

  17. Evolutionary oscillation in prebiology: igneous activity and the origins of life.

    PubMed

    Sylvester-Bradley, P C

    1976-01-01

    The processes of chemical evolution are responsible for the origin of life. Three such processes have special importance: oscillation, creation, and competition. An oscillation from one kind of environment to another provides a mechanism for instituting processes that can only take place under conditions far removed from equilibrium. Oscillating evolutionary processes are likely to have played an important part in the origin of life. It is a mistake to assume that life originated in any one environment. It did not arrive in a moment of time. It was the result of a long period of chemical evolution during which it passed through a variety of environments. Biopoesis took place in an environment in which a variety of different kinds of protolife were assembled and concentrated. One essential form of protolife involved in these processes is the protocell. The experiments of Fox suggest that the creation of protocells involves violent oscillations of temperature and hydration. Igneous activity is especially characterised by oscillating conditions. Volcanic eruptions consist of violent changes from one extreme condition to another. Temperatures, pressure, phase, concentration and hydration all oscillate violently, and are subject to shock pulses of many kinds. Protolife may well have passed through extremes of environment for wider that those that life itself can sustain. The most probable environment for the assembly of the various forms of protolife would be on mudbanks forming either at the mouth of streams draining regions of active vulcanicity, or round the edge of hot volclanic pools. In this situation one could fins concentrated not only the various stands of protolife necessary for the final act of biopoesis, but also perbiologically formed nutrients necessary as for the first eobionts. As soon as the first protocells start to grow, they start to compete with each other, and so initiate a new additional evolutionary process, that of natural selection. Only after

  18. Do the Columbia Hills of Gusev Crater Represent a Layered Igneous Intrusion on Mars?

    NASA Astrophysics Data System (ADS)

    Francis, D.

    2009-12-01

    rocks are assumed to represent cumulate layers whose compositions reflect magmatic sorting, then the estimated olivine compositions (~ Fo 50-60) closely match those indicated to be present by Mössbauer analysis. This correspondence suggests that the rocks analyzed by Spirit may represent crystal cumulates, rather than volcanic liquid compositions, leading to the possibility that the stratification seen at number of localities along Spirit’s traverse represents magmatic sedimentation in a layered igneous intrusion, rather than aqueous, aeolian, or even volcanoclastic sedimentary processes.

  19. 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

  20. Improbability of igneous intrusion promoting a critical event in spent nuclear fuel disposed in unsaturated tuff.

    PubMed

    Rechard, Rob P; Tierney, Martin S

    2005-08-01

    In their regulations, the U.S. Environmental Protection Agency and the U.S. Nuclear Regulatory Commission permit the omission of features, events, or processes with probabilities of <10(-4) in 10(4) yr (e.g., a constant frequency of <10(-8) per yr) in assessments of the performance of radioactive waste disposal systems. Igneous intrusion (or "volcanism") of a geologic repository at Yucca Mountain for radioactive waste is one disruptive event that has a probability with a range of uncertainty that straddles this regulatory criterion and is considered directly in performance assessment calculations. A self-sustained nuclear chain reaction (or "criticality") is another potentially disruptive event to consider, although it was never found to be important when evaluating the efficacy of radioactive waste disposal since the early 1970s. The thesis of this article is that the consideration of the joint event--volcanism and criticality--occurring in any 10,000-year period following closure can be eliminated from performance calculations at Yucca Mountain. The probability of the joint event must be less than the fairly well-accepted but low probability of volcanism. Furthermore, volcanism does not "remove" or "fail" existing hydrologic or geochemical constraints at Yucca Mountain that tend to prevent concentration of fissile material. Prior to general corrosion failure of waste packages, the mean release of fissile mass caused by a low-probability, igneous intrusive event is so small that the probability of a critical event is remote, even for highly enriched spent nuclear fuel owned by the U.S. Department of Energy. After widespread failure of packages occurs, the probability of the joint event is less than the probability of criticality because of the very small influence of volcanism on the mean fissile mass release. Hence, volcanism plays an insignificant role in inducing criticality over any 10(4)-yr period. We also argue that the Oklo reactors serve as a natural

  1. 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

  2. [High Precision Identification of Igneous Rock Lithology by Laser Induced Breakdown Spectroscopy].

    PubMed

    Wang, Chao; Zhang, Wei-gang; Yan, Zhi-quan

    2015-09-01

    In the field of petroleum exploration, lithology identification of finely cuttings sample, especially high precision identification of igneous rock with similar property, has become one of the geological problems. In order to solve this problem, a new method is proposed based on element analysis of Laser-Induced Breakdown Spectroscopy (LIBS) and Total Alkali versus Silica (TAS) diagram. Using independent LIBS system, factors influencing spectral signal, such as pulse energy, acquisition time delay, spectrum acquisition method and pre-ablation are researched through contrast experiments systematically. The best analysis conditions of igneous rock are determined: pulse energy is 50 mJ, acquisition time delay is 2 μs, the analysis result is integral average of 20 different points of sample's surface, and pre-ablation has been proved not suitable for igneous rock sample by experiment. The repeatability of spectral data is improved effectively. Characteristic lines of 7 elements (Na, Mg, Al, Si, K, Ca, Fe) commonly used for lithology identification of igneous rock are determined, and igneous rock samples of different lithology are analyzed and compared. Calibration curves of Na, K, Si are generated by using national standard series of rock samples, and all the linearly dependent coefficients are greater than 0.9. The accuracy of quantitative analysis is investigated by national standard samples. Element content of igneous rock is analyzed quantitatively by calibration curve, and its lithology is identified accurately by the method of TAS diagram, whose accuracy rate is 90.7%. The study indicates that LIBS can effectively achieve the high precision identification of the lithology of igneous rock.

  3. Silicic ash beds bracket Emeishan Large Igneous province to < 1 m.y. at ~ 260 Ma

    NASA Astrophysics Data System (ADS)

    Huang, Hu; Cawood, Peter A.; Hou, Ming-Cai; Yang, Jiang-Hai; Ni, Shi-Jun; Du, Yuan-Sheng; Yan, Zhao-Kun; Wang, Jun

    2016-11-01

    Claystone beds directly below and above the Emeishan basalts in SW China formed around the Guadalupian-Lopingian (G - L) boundary. Zircons from both levels give U-Pb ages of 260 Ma, and are identical within-error to ages reported for the Emeishan Large Igneous Province (LIP). The claystones lack Nb - Ta anomalies on primitive mantle normalized elemental diagrams; zircons from these claystones have a geochemical affinity to within-plate-type magmas. These features, combined with the strong negative Eu anomalies in the zircons and high Al2O3/TiO2 ratios, indicate that claystones around the G - L boundary have a silicic volcanic component related to Emeishan LIP. Zircons from the underlying claystone bed have much higher U/Yb and Th/Nb ratios and lower εHf(t) values than those overlying the LIP, suggesting that early-stage silicic volcanic rocks had a higher crustal contamination or assimilation during magmatic processes. In terms of stratigraphic correlation, our data demonstrate that silicic eruptions occurred not only at the end, but also at the beginning of the Emeishan LIP, and the overall duration of the main basaltic phase was short (< 1 m.y).

  4. Origin of modal and rhythmic igneous layering by sedimentation in a convecting magma chamber

    NASA Astrophysics Data System (ADS)

    Sparks, R. Stephen; Huppert, Herbert E.; Koyaguchi, Takehiro; Hallworth, Mark A.

    1993-01-01

    EXPERIMENTAL investigations of convecting, particle-laden fluids show two regimes for convection driven by cooling from above1. In very dilute suspensions, convection will maintain a homogeneous distribution of particles throughout the convecting layer provided that particle fall velocities are small compared with turbulent fluid velocities. Above a critical concentration, convection is unable to keep the particles suspended, so the particles settle, leaving behind a layer of convecting fluid virtually free of particles. Here we apply these results to cooling magma chambers, in which crystallization leads to an increase in suspended crystal content with time. Discrete sedimentation events are predicted each time the concentration exceeds the critical value. For common igneous minerals, critical concentrations are very small (typically 0.002-0.03 wt%) and layers of the order of centimetres to a few metres thick will result. Because minerals of different density and size have different critical concentrations and settling velocities, complex fluctuations in sedimentation rate and mineral proportions can occur in a multi-component melt. This may lead to either regular repetitive cycles or more complex fluctuations. The process is confined to low-viscosity magmas, such as basalts, in which the crystals are able to separate from the active thermal boundary layer during convection.

  5. 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.

  6. 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.

  7. 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

  8. Examining Different Regions of Relevance: From Highly Relevant to Not Relevant.

    ERIC Educational Resources Information Center

    Spink, Amanda; Greisdorf, Howard; Bateman, Judy

    1998-01-01

    Proposes a useful concept of relevance as a relationship and an effect on the movement of a user through the iterative stages of their information seeking process, and that users' relevance judgments can be plotted on a Three-Dimensional Spatial Model of Relevance Level, Degree and Time. Discusses implications for the development of information…

  9. 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.

  10. 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.

  11. New low-Ni (igneous?) particles among the C and C? types of cosmic dust

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Sutton, S. R.; Bajt, S.; Kloeck, W.

    1993-01-01

    Low-Ni particles with major element abundances, optical properties, and morphologies sufficiently similar to chondritic interplanetery dust particles (IDP's) to receive JSC Cosmic Dust Catalog classifications of C or C?-types were shown to have trace element contents and mineralogies similar to igneous material. Examination of the JSC Catalog EDX spectra by Cooke et al. has shown that 13 percent of the C-type and 38 percent of the C?-type particles are potentially low-Ni particles. Two new low-Ni particles were identified, and it was shown that an additional fragment from the L2002*C cluster has an igneous composition. A newly analyzed fragment of the W7066*A cluster has a chondritic composition. The W7066*A cluster is important because it has yielded a fragment of igneous composition and another fragment having high concentrations of He and Ne suggesting an extraterrestrial origin.

  12. Igneous history of the aubrite parent asteroid - evidence from the Norton County enstatite achondrite

    SciTech Connect

    Okada, A.; Keil, K.; Taylor, G.J.; Newsom, H.

    1988-03-01

    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. 60 references.

  13. 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.

  14. Crystal Size Distributions in Igneous rocks: Where are we now?

    NASA Astrophysics Data System (ADS)

    Higgins, M.

    2003-12-01

    in either slope of intercept is significant and can be related to other parameters. Concave down CSDs, with no small crystals, are commonly encountered in porphyritic, oikocrystic and plutonic rocks. This texture may be produced by textural coarsening (Ostwald ripening, annealing): this occurs when the magma is maintained close to the mineral liquidus. In this situation the nucleation rate is zero, but growth rates are significant. The classic LSW model is not the only solution possible: more modern solutions, such as Communicating Neighbours may be more appropriate. Variable degrees of textural coarsening will produce CSDs that appear to rotate about a single point. This again reflects closure. Concave up CSDs with no lower size limit are very common. They do not generally have a lognormal or fractal size distribution. They can be produced by mixing of two or more magmas, or crystallisation under several different conditions of undercooling. They can also result from alternations of nucleation and growth followed by textural coarsening. Crystal accumulation and fraction should modify existing CSDs in a predictable manner. An exact solution to this problem has not yet been developed, but simplistic models suggest that CSDs should rotate upwards about the size origin for accumulation and downwards for fractionation. However, clear evidence for such effects has not yet been observed, even in well-layered rocks. There are many igneous systems still to be explored using CSDs. An exiting new domain may be the application of CSDs in experimental petrology.

  15. 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

  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.

  17. 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.

  18. 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.

  19. 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.

  20. MULTIPLE EPISODES OF IGNEOUS ACTIVITY, MINERALIZATION, AND ALTERATION IN THE WESTERN TUSHAR MOUNTAINS, UTAH.

    USGS Publications Warehouse

    Cunningham, Charles G.; Steven, Thomas A.; Campbell, David L.; Naeser, Charles W.; Pitkin, James A.; Duval, Joseph S.

    1984-01-01

    The report outlines the complex history of igneous activity and associated alteration and mineralization in the western Tushar Mountains, Utah and pointss out implciations for minerals exploration. The area has been subjected to recurrent episodes of igneous intrusion, hydrothermal alteration, and mineralization, and the mineral-resource potential of the different mineralized areas is directly related to local geologic history. The mineral commodities to be expected vary from one hydrothermal system to another, and from one depth to another within any given system. Uranium and molybdenum seem likely to have the greatest economic potential, although significant concentrations of gold may also exist.

  1. 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

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. Continental igneous rock composition: A major control of past global chemical weathering

    PubMed Central

    Bataille, Clément P.; Willis, Amy; Yang, Xiao; Liu, Xiao-Ming

    2017-01-01

    The composition of igneous rocks in the continental crust has changed throughout Earth’s history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [(87Sr/86Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of (87Sr/86Sr)seawater variations to the strontium isotopic composition (87Sr/86Sr) in igneous rocks generated through time. We demonstrate that the 87Sr/86Sr ratio in igneous rocks is correlated to the epsilon hafnium (εHf) of their hosted zircon grains, and we use the detrital zircon record to reconstruct the evolution of the 87Sr/86Sr ratio in zircon-bearing igneous rocks. The reconstructed 87Sr/86Sr variations in igneous rocks are strongly correlated with the (87Sr/86Sr)seawater variations over the last 1000 million years, suggesting a direct control of the isotopic composition of silicic magmatism on (87Sr/86Sr)seawater variations. The correlation decreases during several time periods, likely reflecting changes in the chemical weathering rate associated with paleogeographic, climatic, or tectonic events. We argue that for most of the last 1000 million years, the (87Sr/86Sr)seawater variations are responding to changes in the isotopic composition of silicic magmatism rather than to changes in the global chemical weathering rate. We conclude that the (87Sr/86Sr)seawater variations are of limited utility to reconstruct changes in the global chemical weathering rate in deep times. PMID:28345044

  11. Continental igneous rock composition: A major control of past global chemical weathering.

    PubMed

    Bataille, Clément P; Willis, Amy; Yang, Xiao; Liu, Xiao-Ming

    2017-03-01

    The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [((87)Sr/(86)Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of ((87)Sr/(86)Sr)seawater variations to the strontium isotopic composition ((87)Sr/(86)Sr) in igneous rocks generated through time. We demonstrate that the (87)Sr/(86)Sr ratio in igneous rocks is correlated to the epsilon hafnium (εHf) of their hosted zircon grains, and we use the detrital zircon record to reconstruct the evolution of the (87)Sr/(86)Sr ratio in zircon-bearing igneous rocks. The reconstructed (87)Sr/(86)Sr variations in igneous rocks are strongly correlated with the ((87)Sr/(86)Sr)seawater variations over the last 1000 million years, suggesting a direct control of the isotopic composition of silicic magmatism on ((87)Sr/(86)Sr)seawater variations. The correlation decreases during several time periods, likely reflecting changes in the chemical weathering rate associated with paleogeographic, climatic, or tectonic events. We argue that for most of the last 1000 million years, the ((87)Sr/(86)Sr)seawater variations are responding to changes in the isotopic composition of silicic magmatism rather than to changes in the global chemical weathering rate. We conclude that the ((87)Sr/(86)Sr)seawater variations are of limited utility to reconstruct changes in the global chemical weathering rate in deep times.

  12. The Late Ordovician crisis: the Large Igneous Province hypothesis tested by global carbon cycle modeling.

    NASA Astrophysics Data System (ADS)

    Lefebvre, Vincent; Servais, Thomas; François, Louis; Averbuch, Olivier

    2010-05-01

    The causes of the well-known Late Ordovician-Hirnantian glaciation remain largely debated. This global cooling event is generally attributed to a severe decrease of atmospheric pCO2 during a time of general greenhouse climate but its duration is not fully determined. The climate perturbation is synchronous with one of the biggest biotic crisis of the Earth history. Some authors have shown that, considering the Ashgillian paleogeography, a drop in pCO2 below a threshold of 8x to 10x PAL (Present Atmospheric Level) may induce a decrease in temperature in high latitudes so that the installation of an ice-sheet on Gondwana could be possible. Such a process requires an intensification of silicate weathering and/or organic carbon burial that are the two major processes potentially driving a decrease in atmospheric pCO2 at the geologic time scale. The Late Ordovician is known to be a period of high mantellic activity marked by a lack of reversal magnetic field and high volcanic activity. Barnes (2004) and Courtillot and Olson (2007) link this process to a superplume event that may give rise to continental basalt flooding. In the present study, we tested this hypothesis with a global carbon cycle numerical box-model coupled with an Energy Balance Climate Model. The Model is an upgrade of that used by Grard et al. (2005) to simulate the environmental impact of the Siberian traps at the P/T boundary. The configuration of the box-model has been set using the Late Ordovician paleogeography. In each oceanic box, the model calculates the evolution of carbon, phosphorus and oxygen concentrations and alkalinity. It also calculates atmospheric pCO2, atmospheric and oceanic δ13C. We tested different scenarios of Large Igneous Province (LIP) emplacements and organic carbon cycle interactions simulating atmospheric pCO2 drops of amplitude large enough to produce the Hirnantian glaciation. We show that the hypothesis of low latitude LIP well accounts for the Late Ordovician climate

  13. Environmentally relevant microorganisms.

    PubMed

    Watanabe, K; Baker, P W

    2000-01-01

    The development of molecular microbial ecology in the 1990s has allowed scientists to realize that microbial populations in the natural environment are much more diverse than microorganisms so far isolated in the laboratory. This finding has exerted a significant impact on environmental biotechnology, since knowledge in this field has been largely dependent on studies with pollutant-degrading bacteria isolated by conventional culture methods. Researchers have thus started to use molecular ecological methods to analyze microbial populations relevant to pollutant degradation in the environment (called environmentally relevant microorganisms, ERMs), although further effort is needed to gain practical benefits from these studies. This review highlights the utility and limitations of molecular ecological methods for understanding and advancing environmental biotechnology processes. The importance of the combined use of molecular ecological and physiological methods for identifying ERMs is stressed.

  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. Analysis and Discrimination of Sedimentary, Metamorphic, and Igneous Rocks Using Laser-Induced Breakdown Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rai, Ab. Kr.; Maurya, G. S.; Kumar, R.; Pathak, A. K.; Pati, J. K.; Rai, Aw. K.

    2017-01-01

    This study deals with the analysis of rocks using laser-induced breakdown spectroscopy (LIBS) coupled with principal component analysis. The spectra of sedimentary, metamorphic, and igneous rock samples were recorded in the 200-900 nm spectral range. The atomic lines of elements such as Si, Ca, Mg, Fe, Na, and K along with lighter elements, namely C, H, N, and O, were observed in these spectra. Multivariate analysis in combination with LIBS was used to classify the samples. For principal component analysis, a 12 × 5849 data matrix was formed using the results of LIBS. The plot of the analysis revealed similarities between the sedimentary and metamorphic rock samples compared with the igneous rock sample. Thus, the present study demonstrates that LIBS coupled with principal component analysis can become an important tool for rapid classification and in-situ discrimination of rock samples.

  16. 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

    2016-10-01

    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.

  17. Igneous lithologies on asteroid (4) Vesta mapped using gamma-ray and neutron data

    NASA Astrophysics Data System (ADS)

    Beck, Andrew W.; Lawrence, David J.; Peplowski, Patrick N.; Viviano-Beck, Christina E.; Prettyman, Thomas H.; McCoy, Timothy J.; McSween, Harry Y.; Yamashita, Naoyuki

    2017-04-01

    We use data collected by the Dawn Gamma-Ray and Neutron Detector (GRaND) at Vesta to map compositions corresponding to nearly pure igneous lithologies in the howardite, eucrite, diogenite (HED) meteorite clan (samples likely from Vesta). At the ∼300-km spatial scale of GRaND measurements, basaltic eucrite occurs on only 3% of the surface, whereas cumulate eucrite and orthopyroxenitic diogenite are not detected. The basaltic eucrite region is generally coincident with an area of the surface with thick regolith, elevated H, and moderate crater density, and may represent the best compositional sample of primordial vestan crust. We observe an absence of pure orthopyroxenitic diogenite terrains in the Rheasilvia basin and its ejecta, an observation corroborated by VIR (0.1%), which suggests the south-polar crust was a polymict mixture of igneous lithologies (howardite) at the time of the Rheasilvia impact, or was a thick basaltic eucrite crust with heterogeneously distributed orthopyroxenitic diogenite plutons. The most dominant igneous composition detected (11% of the surface) corresponds to one of the least-abundant igneous lithologies in the HED meteorite collection, the Yamato Type B diogenites (plagioclase-bearing pyroxenites). The distribution of Type B diogenite is spatially correlated with post-Rheasilvia craters in the north-polar region that are in close proximity to the Rheasilvia basin antipode. This suggests that north-polar Type B plutonism may have been associated with the Rheasilvia impact event. We propose that this was either through 1) uplift of pre-existing plutons at the antipode through focusing of Rheasilvia impact stress, or 2) Rheasilvia impact antipodal crustal melting, creating magmas that underwent fractionation to produce Type B plutons.

  18. Classification and Geochemical Characterization of Igneous Rocks: Southern Part of Chihuahua City, Mexico

    NASA Astrophysics Data System (ADS)

    Fontes, I. D.; Espejel-Garcia, V. V.; Villalobos-Aragon, A.

    2013-05-01

    Chihuahua City is the capital of the state with the same name, located in northern Mexico. The city was established near the Chuviscar River, but in the last decades it has been extended to the nearby areas (mountains), with volcanic (rhyolitic tuffs), and sedimentary rocks (limestone). The study area includes areas in the south part of Chihuahua City, where we can still find unbuilt lands and it is possible to appreciate outcrops of igneous rocks. This project includes 5 study spots, which are located about 9 km. far from the south extreme of the city. This research is developed in order to complement the geological information in this area, as there is no is detailed record of it. In the geological map H13-10 (SGM, 1997), it is said that the urban area is covered by Quaternary conglomerates, while exploring the region we have located several igneous rocks outcrops. In three of the sampling points, dark colored intrusive igneous rocks with large crystals appear in blocks without noticeable fractures. While in the other two sampling points, highly fractured blocks of pink aphanitic igneous rocks, showing traces of pyrolusite were observed. The petrographic study shows the two different textures that classify these rocks as extrusive (aphanitic) or intrusive (phaneritic), both with quartz and feldspars being the dominant minerals. Geochemical analyses confirm the felsic composition of the rocks, varying form trachytes to rhyolites. The trace element results show high contents of Sr, Ba, V, Rb, and Zr in trachytic compositions, while there are high concentrations of Mn, W, Rb and Co for rhyolitic compositions.

  19. 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.

  20. 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.

  1. Strength/Brittleness Classification of Igneous Intact Rocks Based on Basic Physical and Dynamic Properties

    NASA Astrophysics Data System (ADS)

    Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad

    2017-01-01

    This paper sheds further light on the fundamental relationships between simple methods, rock strength, and brittleness of igneous rocks. In particular, the relationship between mechanical (point load strength index I s(50) and brittleness value S 20), basic physical (dry density and porosity), and dynamic properties (P-wave velocity and Schmidt rebound values) for a wide range of Iranian igneous rocks is investigated. First, 30 statistical models (including simple and multiple linear regression analyses) were built to identify the relationships between mechanical properties and simple methods. The results imply that rocks with different Schmidt hardness (SH) rebound values have different physicomechanical properties or relations. Second, using these results, it was proved that dry density, P-wave velocity, and SH rebound value provide a fine complement to mechanical properties classification of rock materials. Further, a detailed investigation was conducted on the relationships between mechanical and simple tests, which are established with limited ranges of P-wave velocity and dry density. The results show that strength values decrease with the SH rebound value. In addition, there is a systematic trend between dry density, P-wave velocity, rebound hardness, and brittleness value of the studied rocks, and rocks with medium hardness have a higher brittleness value. Finally, a strength classification chart and a brittleness classification table are presented, providing reliable and low-cost methods for the classification of igneous rocks.

  2. 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.

  3. 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.

  4. Petrological and Geochemical Studies of the Igneous Rocks at Cerro EL Borrego, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Estrada, V. M.; Espejel-Garcia, V. V.; Villalobos-Aragon, A.

    2013-05-01

    Cerro El Borrego, which is a hill composed of igneous rocks, is located 13.7 km to the SW of Chihuahua city, in northern Mexico. The coordinates of the hill are 28° 11' 07'' N latitude and 105° 33' 23'' W longitude. The study area is within the Basin and Range Physiographic Province, characterized by a complex tectonic-structural pattern, such as elongated ranges with folds and igneous rock formations of Paleogene age. A lava flow of Oligocene age is part of the large volcanic and plutonic activity at the early times of the Cenozoic, which occurred to the NW portion of Mexico. In Cerro El Borrego, the rocks that outcrop are middle Oligocene's rhyolitic tuff to the NW of the hill, while to its SE there is a Pleistocene polymictic conglomerate. Previous work shows different interpretations about the origin and composition of the igneous rocks at Cerro El Borrego. This project includes whole rock and textural analyses, which helped to discern the petrogenesis of these rocks. Preliminary petrographic analyses indicate that the Cerro El Borrego, is a structural dome, and its feldspar-rich rocks contain large crystals that can be appreciated without a microscope. The presence of a porphyritic texture, suggest a sallow intrusion origin. A preliminary conclusion is that Cerro El Borrego is a shallow depth intrusive body with a syenitic composition derived from the Oligocene plutonic activity.

  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. the Deep Biosphere Archaeal Microbial Community in Igneous Ocean Crust

    NASA Astrophysics Data System (ADS)

    Edwards, K. J.

    2014-12-01

    Ridge flank hydrothermal systems represent vast environments that may be habitable by subseafloor microbial life. Oceanic ridge flanks, areas far from the magmatic and tectonic influence of seafloor spreading, comprise one of the largest and least explored microbial habitats on the planet. These potential ecosystems may play a significant role in biogeochemical processes and elemental fluxes that are known to be regulated by these systems. I will discuss the nature of ridge flank hydrothermal environments, and present a framework for delineating a continuum of conditions and processes that are likely to be important for defining subseafloor microbial "provinces." The basis for this framework is three governing conditions that help to determine the nature of subseafloor biomes: crustal age, extent of fluid flow, and thermal state. A brief overview of subseafloor conditions, within the context of these three characteristics for select sites will be described. Technical challenges remain and likely will limit progress in studies of microbial ridge flank hydrothermal ecosystems, which is why it is vital to select and design future studies so as to leverage as much general understanding as possible from work focused at a small number of sites. A characterization framework that perhaps includes alternative or additional physical or chemical characteristics is essential for achieving the greatest benefit from multidisciplinary microbial investigations of oceanic ridge flank hydrothermal systems.

  7. Iridium-imine and -amine complexes relevant to the (S)-metolachlor process: structures, exchange kinetics, and C-H activation by Iri causing racemization.

    PubMed

    Dorta, Romano; Broggini, Diego; Kissner, Reinhard; Togni, Antonio

    2004-09-20

    Iridium complexes of DMA-imine [2,6-dimethylphenyl-1'-methyl-2'-methoxyethylimine, 1 a) and (R)-DMA-amine [(1'R)-2,6-dimethylphenyl-1'-methyl-2'-methoxyethylamine, 2 a] that are relevant to the catalytic imine hydrogenation step of the Syngenta (S)-Metolachlor process were synthesized: metathetical exchange of [Ir2Cl2(cod)2] (cod=1,5-cyclooctadiene) with [Ag(1 a)2]BF4 and [Ag((R)-2 a)2]BF4 afforded [Ir(cod)(kappa2- -1 a)]BF4 (11) and [Ir(cod)(kappa2-(R)-2 a)]BF4 ((R)-19)), respectively. These complexes were then used in stopped-flow experiments to study the displacement of amine 2 a from complex 19 by imine 1 a to form the imine complex 11, thus modeling the product/substrate exchange step in the catalytic cycle. The data suggest a two-step associative mechanism characterized by k1=(2.6+/-0.3) x 10(2) M(-1) s(-1) and k2=(4.3+/-0.6) x 10(-2) s(-1) with the respective activation energies EA1=(7.5+/-0.6) kJ mol(-1) and EA2=(37+/-3) kJ mol(-1). Furthermore, complex 11 reacted with H2O to afford the hydrolysis product [Ir(cod)(eta(6-)-2,6-dimethylaniline)]BF4 (12), and with I2 to liberate quantitatively the DMA-iminium salt 14. On the other hand, the chiral amine complex (R)-19 formed the optically inactive eta6-bound compound [Ir(cod)(eta6-rac-2 a)]BF4 (rac-18) upon dissolution in THF at room temperature, presumably via intramolecular C-H activation. This racemization was found to be a two-step event with k'1=9.0 x 10(-4) s(-1) and k2=2.89 x 10(-5) s(-1), featuring an optically active intermediate prior to sp3 C-H activation. Compounds 11, 12, rac-18, and (R)-19 were structurally characterized by single-crystal X-ray analyses.

  8. 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

  9. Rubidium-87/strontium-87 age of juvinas basaltic achondrite and early igneous activity in the solar system.

    PubMed

    Allégre, C J; Birck, J L; Fourcade, S; Semet, M P

    1975-02-07

    A (4.60+/-0.07)x10(9) year internal isochron has been drawn for the achondrite Juvinas by the rubidium-87/strontium-87 method. Earlier petrographic investigation of achondrites supplemented by a new ion microprobe study of Juvinas strongly suggest an igneous origin for this class of meteorites. The results thus indicate that igneous activity may have rapidly followed the formation of the achondrites' parent body 4.6x10(9) years ago.

  10. Magmatic complexes of the Urals as suspect parts of Large Igneous Provinces

    NASA Astrophysics Data System (ADS)

    Puchkov, Victor

    2016-10-01

    Petrogenetic, geochemical studies and isotope age determinations of flood basalts, dolerites, trachybasalts, picrite-basalts, rapakivi granites, layered mafic-ultramafic intrusions and also alkaline and carbonatite magmatic complexes of the Urals permit to put forward a preliminary list of objects - “candidates” at being attributed to Large Igneous Provinces (LIPs) - manifestations of superplume activity. Their petro-geochemical properties distinguish them from spreading and subduction types, and are closer to epicontinental rift zones. They are characterized by wide areas of development and very short periods of activity. In the Southern Urals near the base of the Lower Riphean (Uppermost Paleoproterozoic and Lower Mesoproterozoic) there are volcanic deposits of the Navysh Subformation, represented by trachybasalts. The age of the unit was determined as 1752 ± llMa. Volcanic rocks of the age level of 1750-1780 Ma are developed not only in some other places of Baltica, but also in the Northern Africa, Siberia, Laurentia (parts of Nuna supercontinent). Therefore, they may belong to a LIP. Higher up the section of the Riphean, at the base of the Middle Riphean (Mid-Mesoproterozoic), rhyolites of the basalt-rhyolite Mashak Formation were dated as 1380-1385 Ma. The same ages have also rapakivi granites, layered gabbro, carbonatites and dolerite dykes developed in the Southern Urals and encountered in boreholes of the East European platform; magmatic rocks of the same age are traced to Laurentia and Siberian cratons and date the beginning of Nuna supercontinent break-up. Less confidently we may speak of the younger Neoproterozoic magmatic complexes of the Southern Urals as LIPs, dated as ca. 720 Ma and 680 Ma (Arshinian and Kiryabinka complexes); they need a further study. The next in the succession of magmatic episodes, represented by subalkaline volcanics, is connected with a rift process that started at ca. 490 Ma, that led to oceanic spreading and formation of

  11. 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…

  12. 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.

  13. 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

  14. 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.

  15. A Review of Computerized Team Performance Measures to Identify Military-Relevant, Low-to-Medium Fidelity Tests of Small Group Effectiveness during Shared Information Processing

    DTIC Science & Technology

    2012-05-01

    the Team Resource Management Test ( REMAN ) are derived from still earlier tests such as the Multiple Task Performance Battery (MTPB) and Distributed... REMAN below, but not the earliest tests such as MTPB or DREAM. It should be noted that this type of exclusion was rare, since most tests have kept...Relevant Assessment of Combat Teams (TRACTs) (1) Fowlkes et al. (1999) e. Team Resource Management Test ( REMAN ) (1) Woldring and Issac (1999) (2

  16. 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

  17. 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.

  18. Development and Experimental Validation of Large Eddy Simulation Techniques for the Prediction of Combustion-Dynamic Process in Syngas Combustion: Characterization of Autoignition, Flashback, and Flame-Liftoff at Gas-Turbine Relevant Operating Conditions

    SciTech Connect

    Ihme, Matthias; Driscoll, James

    2015-08-31

    The objective of this closely coordinated experimental and computational research effort is the development of simulation techniques for the prediction of combustion processes, relevant to the oxidation of syngas and high hydrogen content (HHC) fuels at gas-turbine relevant operating conditions. Specifically, the research goals are (i) the characterization of the sensitivity of syngas ignition processes to hydrodynamic processes and perturbations in temperature and mixture composition in rapid compression machines and ow-reactors and (ii) to conduct comprehensive experimental investigations in a swirl-stabilized gas turbine (GT) combustor under realistic high-pressure operating conditions in order (iii) to obtain fundamental understanding about mechanisms controlling unstable flame regimes in HHC-combustion.

  19. Petrogenesis of the Bashisuogong bimodal igneous complex in southwest Tianshan Mountains, China: Implications for the Tarim Large Igneous Province

    NASA Astrophysics Data System (ADS)

    Ma, Yuan; Zhang, Zhaochong; Huang, He; Santosh, M.; Cheng, Zhiguo

    2016-11-01

    The Bashisuogong (BSSG) complex is located in the tectonic transition zone between South Tianshan Collisional Belt (STCB) and Tarim Block (TB). The complex is composed of a mafic unit (mainly including gabbro and diabase) and a felsic unit (mainly composed of quartz syenite and alkali granite), both of which are crosscut by several diabase and alkali granite dykes. Here we present LA-ICP-MS zircon U-Pb data which show that the two units were emplaced coevally at 276 Ma. The rocks from the two units display a wide SiO2 gap, implying a typical bimodal magmatic feature. The petrographic and geochemical evidence such as mafic microgranular enclave (MME) within the syenite, negative linear correlations between SiO2 and some major elements, and a wide range of (87Sr/86Sr)i suggest that the syenite formed via magma mixing process. The positive εNd(t) values (+ 5.42 to + 5.66 for gabbro and + 4.70 to + 5.02 for diabase) and OIB-like geochemical features of the mafic unit indicate that the parent magma was derived from asthenospheric mantle or mantle plume. The felsic unit shows higher contents of SiO2, K2O and total alkalis. Their trace element patterns are characterized by Rb, Y, Zr and Hf enrichment, and high 10,000 Ga/Al ratios, indicating an A1-type affinity. The syenite shows εNd(t) values in the range of - 0.15 to + 0.30 and zircon εHf(t) values of + 1.68 to + 5.10, whereas the alkali granite has εNd(t) values of - 2.10 to - 1.92 and εHf(t) values of - 4.10 to + 0.32. The two stage Hf isotope model ages of zircon grains in the syenite are older than 1.0 Ga, whereas those of the alkali granite are even older (> 1.3 Ga). Our results suggest that the alkali granite was generated by partial melting of a Neoproterozoic gabbroic source. Zircon grains in the A1-type felsic intrusions yield high Zr saturation temperature (728-983 °C). Although the OIB-like affinities and high temperature zircon grains of the BSSG complex suggest a genetic link with the Tarim mantle

  20. 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.

  1. 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.

  2. 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…

  3. 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.

  4. 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.

  5. 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.

  6. Alteration assemblages in the Miller Range and Elephant Moraine regions of Antarctica: Comparisons between terrestrial igneous rocks and Martian meteorites

    NASA Astrophysics Data System (ADS)

    Hallis, L. J.

    2013-02-01

    The weathering products present in igneous terrestrial Antarctic samples were analyzed, and compared with those found in the four Miller Range nakhlite Martian meteorites. The aim of these comparisons was to determine which of the alteration phases in the Miller Range nakhlites are produced by terrestrial weathering, and what effect rock composition has on these phases. Antarctic terrestrial samples MIL 05031 and EET 96400, along with the Miller Range nakhlites MIL 03346 and 090032, were found to contain secondary alteration assemblages at their externally exposed surfaces. Despite the difference in primary mineralogy, the assemblages of these rocks consist mostly of sulfates (jarosite in MIL 05031, jarosite and gypsum in EET 96400) and iddingsite-like Fe-clay. As neither of the terrestrial samples contains sulfur-bearing primary minerals, and these minerals are rare in the Miller Range nakhlites, it appears that SO42-, possibly along with some of the Na+, K+, and Ca+ in these phases, was sourced from wind-blown sea spray and biogenic emissions from the southern ocean. Cl enrichment in the terrestrially derived "iddingsite" of MIL 05031 and MIL 03346, and the presence of halite at the exterior edge of MIL 090032, can also be explained by this process. However, jarosite within and around the olivine-bound melt inclusions of MIL 090136 is present in the interior of the meteorite and, therefore, is probably the product of preterrestrial weathering on Mars.

  7. Effects of Compositional and Structural Variations on Log Responses in Igneous and Metamorphic Rocks

    NASA Astrophysics Data System (ADS)

    Pechnig, R.; Bartetzko, A.; Delius, H.

    2001-12-01

    Petrophysical in-situ data of several boreholes drilled igneous and metamorphic rocks of continental and oceanic basement were analyzed in order to characterize and classify the occurring rock types. Since physical properties of crystalline rocks are controlled by both, compositional and structural features, one objective of this study was to develop methods to detect and quantify matrix effects. The comparison of mineralogical and geochemical core data with wireline data reveal following systematic observations: (1) Mafic rocks (e.g. oceanic basalts, volcanic island basalts, gabbros and amphibolites) generally have low contents of radioactive minerals. This is in particular valid for mafic rocks from the upper and lower oceanic crust. Slight increases in gamma-ray are related to an enrichment in potassium due to seafloor alteration. In contrast to this uniform, mantle source controlled rocks, extrusives and re-sedimented material from ocean islands and large igneous provinces show a large scatter in gamma-ray responses as a result of their more complex evolution. Mafic rocks recovered from boreholes into continental crust, are characterized by high gamma-ray values, due to enrichment of thorium and uranium during regional metamorphism. In contrast to the mafic plutonic and metamorphic rocks, where the density and p-wave velocity is controlled by the mineralogical composition, the physical parameters of mafic volcanic rocks are strongly affected by fracturing and vesicularity. Density, p-wave velocity and electrical resistivity logs are significantly lowered depending on the degree of vesicularity and fracturing. (2) Acid to intermediate igneous rocks and orthogneisses are distinguishable from paragneisses by their log responses despite showing a similar geochemical composition. The main difference occurs for the relation of the gamma-ray log to the density and neutron porosity log. The gamma-ray in paragneisses is controlled by the amount of phyllosilicates, which

  8. Primary Igneous Anhydrite: Progress Since the 1982 El Chichón Eruption (Mexico)

    NASA Astrophysics Data System (ADS)

    Luhr, J. F.

    2006-05-01

    Anhydrite (CaSO4) was confirmed as a stable primary igneous mineral, capable of precipitating from a silicate melt, through petrographic observations of fresh trachyandesitic pumices erupted in the spring of 1982 from El Chichón, a little known, isolated tuff and lava-dome complex in eastern Mexico. The 1982 eruption was also notable for the associated release of an estimated 5-9 megatons of SO2 to the stratosphere and troposphere, as measured by the Total Ozone Mapping Spectrometer. Subsequent years saw confirmation of primary igneous anhydrite in laboratory phase-equilibrium experiments, and anhydrite was also observed in the products of several subsequent explosive eruptions, most importantly dacitic pumices from the massive 15 June 1991 eruption of Mount Pinatubo, in the Philippines. That eruption involved ~5X the mass of magma and ~3X the mass of SO2 release compared to El Chichón's eruption. For both the Pinatubo and El Chichón eruptions, it has been concluded that the sulfur released to the atmosphere was too great in mass to have been dissolved in the erupted melt volume just prior to eruption. In both cases workers advocated the existence of a separate gas phase prior to eruption, where much of the subsequently released sulfur was present. Thus, primary igneous anhydrite has been linked with another important phenomenon: excess sulfur release during volcanic eruptions. This presentation will review other developments concerning primary igneous anhydrite since 1982. These include: (1) other examples of primary anhydrite from volcanic samples (Nevado del Ruiz, Colombia; Lascar, Chile; Sutter Buttes, USA; Eagle Mountain, USA; Shiveluch, Russia; (2) examples of primary anhydrite from plutonic samples (Julcani, Peru; Santa Rita, USA; Cajon Pass Scientific Drillhole, USA); (3) laboratory experiments that have expanded our understanding of the T-P-fO2 conditions of anhydrite stability, melt/vapor partition coefficients for sulfur as a function of these

  9. 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.

  10. 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

  11. 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.

  12. Synmagmatic deformation in the underplated igneous complex of the Ivrea-Verbano zone

    USGS Publications Warehouse

    Quick, J.E.; Sinigoi, S.; Negrini, L.; Demarchi, G.; Mayer, A.

    1992-01-01

    The Ivrea-Verbano zone, northern Italy, contains an igneous complex up to 10km thick that is thought to have been intruded near the interface between the continental crust and mantle during the late Paleozoic. New data indicate that this complex is pervasively deformed and concentrically foliated. The presence of analogous features in ophiolitic gabbros suggests that emplacement of the Ivrea-Verbano zone plutonic rocks involved large-scale flow of crystal mush in a dynamic, and possibly extensional, tectonic environment. -from Authors

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Possible petrogenetic associations among igneous components in North Massif soils: Evidence in 2-4 MM soil particles from 76503

    NASA Astrophysics Data System (ADS)

    Jolliff, Bradley L.; Bishop, Kaylynn M.; Haskin, Larry A.

    1992-12-01

    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.

  18. 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.

  19. Relevance Is the Issue.

    ERIC Educational Resources Information Center

    Smeltzer, Larry

    1993-01-01

    Points out that good research must be applied, theoretical, rigorous, and relevant all at the same time. Argues for relevant research that develops and tests theoretical constructs that provide useful business knowledge. (SR)

  20. 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.

  1. A melt inclusion study of the Sudbury Igneous Complex (Ontario, Canada): preliminary results

    NASA Astrophysics Data System (ADS)

    Watts, Kathleen; Hanley, Jacob; Kontak, Daniel; Ames, Doreen

    2013-04-01

    The 1.85 Ga Sudbury Igneous Complex (SIC), Ontario, Canada, is an intrusive complex representing the crystallized melt sheet that formed within a large impact crater. The SIC has been extensively studied due to its rich endowment in magmatic sulfide ores (Ni-Cu-PGEs). The nature and origin of the SIC melt sheet and its subsequent evolution still remain controversial. In this study, analyses of primary melt inclusions hosted in cumulus apatite within three mafic units of the SIC (gabbro, norite and sublayer quartz diorite) are used to decipher the thermometric and chemical characteristics of the evolving melt sheet as it crystallized. Apatite-hosted melt inclusions commonly display a negative crystal shape, occur parallel to the c-axis, and often occur within a central growth zone, which suggest a primary origin. The compositions of coeval (co-entrapped) melt inclusions are distinct and may represent either the products of immiscibility (low or high temperature field; c.f. the Skaergaard Intrusion: Jakobsen et al., Geology, 2005), or a product of early, high-temperature, impact-generated emulsification (prior to and independent of crystallization of the melt sheet). The compositions of homogenized (1100-1200oC for 3 hrs) melt inclusions, determined by SEM-EDS and EMP analyses of opened, homogenized melt inclusions, equate to two distinct compositions: (1) Type-I are SiO2-rich, ranging from tonalitic to granodioritic in composition (60-70 wt% SiO2, up to 11 wt% FeO); and (2) Type-II are Fe-rich with syenogabbroic to essexitic to alkali gabbroic compositions (27-49 wt% SiO2, 16-44 wt% FeO). Trace element data, obtained by LA-ICPMS analyses of single inclusions and surrounding host apatite, are used to infer D values between apatite and the two melt types, and between the coexisting melt types. Apparent Dap-melt values for both Type-I and Type-II inclusions show that the REE, Sr, and Y are compatible in apatite, and As is weakly compatible or incompatible in apatite

  2. Regional uplift associated with continental large igneous provinces: The roles of mantle plumes and the lithosphere

    USGS Publications Warehouse

    Saunders, A.D.; Jones, S.M.; Morgan, L.A.; Pierce, K.L.; Widdowson, M.; Xu, Y.G.

    2007-01-01

    The timing and duration of surface uplift associated with large igneous provinces provide important constraints on mantle convection processes. Here we review geological indicators of surface uplift associated with five continent-based magmatic provinces: Emeishan Traps (260??million years ago: Ma), Siberian Traps (251??Ma), Deccan Traps (65??Ma), North Atlantic (Phase 1, 61??Ma and Phase 2, 55??Ma), and Yellowstone (16??Ma to recent). All five magmatic provinces were associated with surface uplift. Surface uplift can be measured directly from sedimentary indicators of sea-level in the North Atlantic and from geomorpholocial indicators of relative uplift and tilting in Yellowstone. In the other provinces, surface uplift is inferred from the record of erosion. In the Deccan, North Atlantic and Emeishan provinces, transient uplift that results from variations in thermal structure of the lithosphere and underlying mantle can be distinguished from permanent uplift that results from the extraction and emplacement of magma. Transient surface uplift is more useful in constraining mantle convection since models of melt generation and emplacement are not required for its interpretation. Observations of the spatial and temporal relationships between surface uplift, rifting and magmatism are also important in constraining models of LIP formation. Onset of surface uplift preceded magmatism in all five of the provinces. Biostratigraphic constraints on timing of uplift and erosion are best for the North Atlantic and Emeishan Provinces, where the time interval between significant uplift and first magmatism is less than 1??million years and 2.5??million years respectively. Rifting post-dates the earliest magmatism in the case of the North Atlantic Phase 1 and possibly in the case of Siberia. The relative age of onset of offshore rifting is not well constrained for the Deccan and the importance of rifting in controlling magmatism is disputed in the Emeishan and Yellowstone

  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. 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

  5. Zirconolite: A new U-Pb chronometer for mafic igneous rocks

    NASA Astrophysics Data System (ADS)

    Rasmussen, Birger; Fletcher, Ian R.

    2004-09-01

    Precise dates for mafic igneous events are essential for tectonic reconstructions and understanding mantle dynamics, mass extinctions, and paleoclimate. Zirconolite (CaZrTi2O7) is a uranium-bearing accessory mineral, found in a wide range of terrestrial and lunar rocks, that has been largely overlooked as a chronometer. In situ U-Pb geochronology of zirconolite from three dolerite intrusions in Western Australia demonstrates that it yields emplacement ages that are more precise than those obtained from coexisting zircon and baddeleyite. Dikes in the Stirling Range Formation give a zirconolite 207Pb/ 206Pb age of 1218 ± 3 Ma, indistinguishable from the less precise dates obtained from zircon (1215 ± 10 Ma) and baddeleyite (1217 ± 39 Ma) and coincident with dike emplacement in the adjacent craton margin and peak metamorphism in the Albany-Fraser orogen. Zirconolite from the 755 Ma Mundine Well dike swarm yields a 207Pb/206Pb age of 754 ± 5 Ma. Sills intruding the Proterozoic Manganese Group contain zirconolite crystals that give a 207Pb/206Pb age of 523 ± 14 Ma. Despite high U contents (550 ppm to 14,000 ppm) and greenschist facies metamorphism, zirconolite in these samples is apparently unaffected by loss of radiogenic Pb. Because of its remarkable properties for U-Pb geochronology, it may soon become the dominant tool for dating mafic igneous rocks as young as 500 Ma by ion microprobe, and thus will prove especially valuable in reconstructing Precambrian geologic history.

  6. 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.

  7. A trishear model for the deformation of the Sudbury Igneous Complex, Canada

    NASA Astrophysics Data System (ADS)

    Lenauer, Iris; Riller, Ulrich

    2017-04-01

    The Sudbury Igneous Complex (SIC), Canada, is an impact-induced layered sheet of crystalline rocks deformed into an asymmetrical fold basin, the Sudbury Basin. The basin geometry at depth is largely unknown as few attempts were made to quantify displacement and rotation of layer contacts. We propose that the dip of layer contacts and foliation surfaces in the southern SIC can be approximated by trishear fault propagation folding. Trishear deformation accounts for: (1) angular discordances between upper and basal SIC contacts, (2) local overturning of the SIC, (3) progressive steepening of foliation surfaces from NW to SE, (4) strain gradient in the Sudbury Basin sedimentary rocks, and (5) thickness variations in SIC layers. Moreover, the South Range Shear Zone, a zone of moderately strong metamorphic fabrics, coincides with the surface manifestation of the proposed trishear zone. We demonstrate the use of structural data together with forward kinematic modelling to identify the strain distribution within the SIC, rotation of SIC contacts and thickness changes of SIC layers. Backward kinematic modelling provides information on the initial geometry of the SIC and is used to restore the shape of the igneous sheet, showing that the SIC was shortened by approximately 10 km in NW-SE diameter. Most of the shortening was accommodated by 40% reduction in the thickness of the upper SIC layer.

  8. Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction.

    PubMed

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

    2013-12-04

    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.

  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. Thermal neutron absorption cross sections for igneous rocks: Newberry Caldera, Oregon

    SciTech Connect

    Lysne, P.

    1990-01-01

    The thermal neutron absorption cross sections of geologic materials are of first-order importance to the interpretation of pulsed neutron porosity logs and of second-order importance to the interpretation of steady-state porosity logs using dual detectors. Even in the latter case, uncertainties in log response can be excessive whenever formations are encountered that possess absorption properties appreciably greater than the limestones used in most tool calibrations. These effects are of importance to logging operations directed at geothermal applications where formation vary from igneous to sedimentary and which may contain solution-deposited minerals with very large cross-section values. Most measurements of cross-section values for geologic materials have been made for hydrocarbon production applications. Hence, the specimen materials are sedimentary and clean in the sense that they are not altered by geothermal fluids. This investigation was undertaken to measure cross-section values from a sequence of igneous materials obtained from a single hole drilled in an active hydrothermal system. 3 refs., 1 fig.

  11. Plume or no plume: Emeishan Large Igneous Province in Southwest China revisited from receiver function analysis

    NASA Astrophysics Data System (ADS)

    He, Chuansong; Santosh, M.; Wu, Jianping; Chen, Xuanhua

    2014-07-01

    The Late Permian Emeishan Large Igneous Province at the western margin of the Yangtze craton and eastern Tibet is popularly regarded as the signature of mantle plume impingement onto the lithosphere. In this study, we investigate the crustal structure and upper mantle discontinuities of this region by employing H-k stacking of receiver function and depth domain receiver function. Our results image the mantle transition zone. However, no vestiges of any mantle plume upwelling in this area are recorded in our results, and the region is characterized by a largely cold domain. In contrast, our data reveal a region of lower crustal delamination that coincides with the cold mantle transition zone. We therefore suggest that the delaminated lower crustal material was recycled into the upper mantle or the mantle transition zone, turning the latter into a cold domain. The delamination of the lower crust might have also led to asthenospheric upwelling and plume-like upwelling from the mantle transition zone that generated the basalts in the Emeishan Large Igneous Province.

  12. 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

  13. 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.

  14. Igneous inclusions from ordinary chondrites: High temperature cumulates and a shock melt

    NASA Technical Reports Server (NTRS)

    Sack, Richard O.; Ghiorso, Mark, S.; Wang, Ming-Sheng; Lipschutz, Michael E.

    1994-01-01

    We report microprobe, instrumental neutron activation analysis, and radiochemical neutron activation analysis data for three large igneous inclusions in the Yamato (Y-)75097, Y-793241, and Y-794046 ordinary chondrites. The inclusions in the first two chondrites are troctolitic cumulates that have undergone appreciable reactions with their hosts either during emplacement and/or cooling. Olivine-spinel Fe-Mg exchange pairs in these two inclusions record equilibration temperatures of about 710 C, and these temperatures are similar to those exhibited by mineral pairs in the Y-75097 and Y-793241 hosts. The inclusion in Y-794046 is texturally unique, consisting of fine-grained, randomly distributed olivines, coarse (approximately 2 mm) fascicular pyroxene laths, and angular pockets of maskelynite/plagioclase feldspar. The phase compositions are readily interpreted as having resulted from extremely rapid, essentially isochemical cooling to temperatures less than 1000 C of a melt with an initial temperature greater than 1670 C. We suggest that this igneous inclusion formed in-situ by shock.

  15. Three-dimensional imaging of impact of a large igneous province with a subduction zone

    NASA Astrophysics Data System (ADS)

    Reyners, Martin; Eberhart-Phillips, Donna; Upton, Phaedra; Gubbins, David

    2017-02-01

    How the thickened crust of a large igneous province on an incoming oceanic plate is accommodated at a subduction zone remains an open question. New Zealand is one of the few places to study this, as at ca. 105 Ma the ca. 35 km-thick Hikurangi Plateau impacted the Gondwana subduction zone in what is now the South Island. Here we report on results from a forty-station portable seismograph array in the southern South Island, designed to delineate the leading edge of the subducted plateau. Three-dimensional images of Vp and Vp/Vs reveal the southwestern part of the plateau was a relatively narrow salient, and the first part to be subducted. The plateau then rotated clockwise about this salient until the southern edge of the plateau was parallel to subduction strike and subduction ceased at ca. 100 Ma. Our results suggest that the global-scale plate reorganization event at 105-100 Ma was due to a cessation of subduction caused by the Hikurangi Plateau choking the Gondwana subduction zone, rather than the subduction of mid ocean ridges as previously proposed. The choking of Gondwana subduction by the plateau also led to a concentration of slab pull in the adjacent subducted oceanic crust, explaining the episode of basin opening and intraplate magmatism there that occurred at the same time. Our study underlines the havoc caused by impact of a large igneous province with a subduction zone.

  16. Identification of functionally relevant populations in enhanced biological phosphorus removal processes based on intracellular polymers profiles and insights into the metabolic diversity and heterogeneity.

    PubMed

    Majed, Nehreen; Chernenko, Tatyana; Diem, Max; Gu, April Z

    2012-05-01

    This study proposed and demonstrated the application of a new Raman microscopy-based method for metabolic state-based identification and quantification of functionally relevant populations, namely polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), in enhanced biological phosphorus removal (EBPR) system via simultaneous detection of multiple intracellular polymers including polyphosphate (polyP), glycogen, and polyhydroxybutyrate (PHB). The unique Raman spectrum of different combinations of intracellular polymers within a cell at a given stage of the EBPR cycle allowed for its identification as PAO, GAO, or neither. The abundance of total PAOs and GAOs determined by Raman method were consistent with those obtained with polyP staining and fluorescence in situ hybridization (FISH). Different combinations and quantities of intracellular polymer inclusions observed in single cells revealed the distribution of different sub-PAOs groups among the total PAO populations, which exhibit phenotypic and metabolic heterogeneity and diversity. These results also provided evidence for the hypothesis that different PAOs may employ different extents of combination of glycolysis and TCA cycle pathways for anaerobic reducing power and energy generation and it is possible that some PAOs may rely on TCA cycle solely without glycolysis. Sum of cellular level quantification of the internal polymers associated with different population groups showed differentiated and distributed trends of glycogen and PHB level between PAOs and GAOs, which could not be elucidated before with conventional bulk measurements of EBPR mixed cultures.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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…

  2. 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

  3. Structural changes on a molecular basis of canola meal by conditioning temperature and time during pelleting process in relation to physiochemical (energy and protein) properties relevant to ruminants

    PubMed Central

    Huang, Xuewei; Zhang, Huihua; Yu, Peiqiang

    2017-01-01

    The objectives of this study were: (1) To investigate the effects of conditioning temperature (70, 80, 90°C), time (30, 60 sec), and interaction (temperature × time) during the pelleting process on internal protein molecular structure changes of the co-products; (2) To identify differences in protein molecular structures among pellets that were processed under different conditions, and between unprocessed mash and pellets; 3) To quantify protein molecular structure changes in relation to predicted energy and protein utilization in dairy cows. The final goal of this program was to show how processing conditions changed internal feed structure on a molecular basis and how molecular structure changes induced by feed processing affected feed milk value in dairy cows. The hypothesis in this study was that processing-induced protein inherent structure changes affected energy and protein availability in dairy cattle and the sensitivity and response of protein internal structure to the different pelleting process conditions could be detected by advanced molecular spectroscopy. The protein molecular structures, amides I and II, amide I to II ratios, α-helix structure, β-sheet structure, and α to β structure ratios, were determined using the advanced vibrational molecular spectroscopy (ATR-FT/IR). The energy values were determined using NRC2001 summary approach in terms of total digestible nutrients, metabolizable and net energy for lactation. The protein and carbohydrate subfactions that are related to rumen degradation characteristics and rumen undegraded protein supply were determined using updated CNCPS system. The experiment design was a RCBD and the treatment design was a 3x2 factorial design. The results showed that pelleting induced changes in protein molecular structure. The sensitivity and response of protein inherent structure to the pelleting depended on the conditioning temperature and time. The protein molecular structure changes were correlated (P < 0

  4. Structural changes on a molecular basis of canola meal by conditioning temperature and time during pelleting process in relation to physiochemical (energy and protein) properties relevant to ruminants.

    PubMed

    Huang, Xuewei; Zhang, Huihua; Yu, Peiqiang

    2017-01-01

    The objectives of this study were: (1) To investigate the effects of conditioning temperature (70, 80, 90°C), time (30, 60 sec), and interaction (temperature × time) during the pelleting process on internal protein molecular structure changes of the co-products; (2) To identify differences in protein molecular structures among pellets that were processed under different conditions, and between unprocessed mash and pellets; 3) To quantify protein molecular structure changes in relation to predicted energy and protein utilization in dairy cows. The final goal of this program was to show how processing conditions changed internal feed structure on a molecular basis and how molecular structure changes induced by feed processing affected feed milk value in dairy cows. The hypothesis in this study was that processing-induced protein inherent structure changes affected energy and protein availability in dairy cattle and the sensitivity and response of protein internal structure to the different pelleting process conditions could be detected by advanced molecular spectroscopy. The protein molecular structures, amides I and II, amide I to II ratios, α-helix structure, β-sheet structure, and α to β structure ratios, were determined using the advanced vibrational molecular spectroscopy (ATR-FT/IR). The energy values were determined using NRC2001 summary approach in terms of total digestible nutrients, metabolizable and net energy for lactation. The protein and carbohydrate subfactions that are related to rumen degradation characteristics and rumen undegraded protein supply were determined using updated CNCPS system. The experiment design was a RCBD and the treatment design was a 3x2 factorial design. The results showed that pelleting induced changes in protein molecular structure. The sensitivity and response of protein inherent structure to the pelleting depended on the conditioning temperature and time. The protein molecular structure changes were correlated (P < 0

  5. 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

  6. 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

  7. The relevance of low skin temperature inhibiting histamine-induced itch to the location of contact urticarial symptoms in the fish processing industry.

    PubMed

    Halkier-Sørensen, L; Thestrup-Pedersen, K

    1989-09-01

    We have studied the influence of cold exposure on itch, erythema and wheal, in response to histamine scratch tests, in 14 volunteers. Cooling of the skin to less than 20 degrees C, by application of an ice cube for 30 min on the inside of the forearm, abolished itch and reduced erythema by approximately 50%, whereas the size of the wheal was unaffected by cooling. The observations bear significance for an explanation of the well-known observation that cold relieves itch. A normal itch response seems to require a continuous metabolic process in the skin, which is inhibited at temperatures less than 20 degrees C. The skin symptoms, itching and erythema, among workers in the fish processing industry are mainly localized to the forearms and backs of the hands, but only seldom to the fingers and palms, although they are in direct contact with fish products. Skin temperature measurements have shown that the temperature on the fingers and palms is less than 20 degrees C, while the temperature on the backs of the hands and forearms ranges from 25 to 30 degrees C. We therefore conclude that the skin temperature is an important factor for the location of skin symptoms among workers in the fish processing industry.

  8. Experimental investigations on the state of the friction-welded joint zone in steel hybrid components after process-relevant thermo-mechanical loadings

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Bouguecha, A.; Vucetic, M.; Peshekhodov, I.; Matthias, T.; Kolbasnikov, N.; Sokolov, S.; Ganin, S.

    2016-10-01

    As a part of the newly established Collaborative Research Center 1153 (SFB 1153) "Process chain for the manufacturing of hybrid high-performance components by tailored forming" at the Leibniz Universität Hannover, the Institute of Forming Technology and Machines (IFUM) examines the influence of thermo-mechanical stresses on the reduced Young's modulus as well as the hardness of hybrid (steel-steel compound) joined semi-finished products. Currently the expertise in the production of bulk metal formed parts is limited to mono-materials. For manufacturing parts of hybrid materials and also for the methods of the new process routes, practical experience has to be gained. The subproject C1 within the collaborative research center 1153 with the short title "Failure Prediction" deals with the question, if the hybrid semi-finished products fulfill the thermo-mechanical demands or if they fail at the joining zone (JZ) during forging. For this purpose, stresses similar to those in the process were imposed on hybrid semi-finished products by torsion tests by using the thermo-mechanical test system Gleeble 3800. Afterwards, the specimens were examined metallographically and by nanoindentations with the help of a TriboIndenter TI950. Thus, first knowledge on the behaviour of thermo-mechanical stresses on the reduced Young's modulus and the hardness of hybrid joined semi-finished parts was gained.

  9. 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

  10. 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

    2016-11-01

    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.

  11. Process development of itaconic acid production by a natural wild type strain of Aspergillus terreus to reach industrially relevant final titers.

    PubMed

    Krull, Susan; Hevekerl, Antje; Kuenz, Anja; Prüße, Ulf

    2017-02-25

    Itaconic acid is a promising organic acid and is commercially produced by submerged fermentation of Aspergillus terreus. The cultivation process of the sensitive filamentous fungus has been studied intensively since 1932, with respect to fermentation media components, oxygen supply, shearing rate, pH value, or culture method. Whereas increased final titers were achieved over the years, the productivity has so far remained quite low. In this study, the impact of the pH on the itaconic acid production was investigated in detail. The pH during the growth and production phase had a significant influence on the final itaconic acid concentration and pellet diameter. The highest itaconic acid concentration of 160 g/L was achieved at a 1.5-L scale within 6.7 days by raising and controlling the pH value to pH 3.4 in the production phase. An ammonia solution and an increased phosphate concentration were used with an itaconic acid yield of 0.46 (w/w) and an overall productivity of 0.99 g/L/h in a fed-batch mode. A cultivation with a lower phosphate concentration resulted in an equal final concentration with an increased yield of 0.58 (w/w) after 11.8 days and an overall productivity of 0.57 g/L/h. This optimized process was successfully transferred from a 1.5-L scale to a 15-L scale. After 9.7 days, comparable pellet morphology and a final concentration of 150 g/L itaconic acid was reached. This paper provides a process strategy to yield a final titer of itaconic acid from a wild-type strain of A. terreus which is in the same range as the well-known citric acid production.

  12. β-decay half-lives and β-delayed neutron emission probabilities of nuclei in the region A≲110, relevant for the r process

    NASA Astrophysics Data System (ADS)

    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.; Möller, P.; Montes, F.; Pfeiffer, B.; Schatz, H.; Schertz, F.; Schnorrenberger, L.; Smith, E.; Stolz, A.; Quinn, M.; Walters, W. B.; Wöhr, A.

    2009-03-01

    Measurements of β-decay properties of A≲110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory at Michigan State University. β-decay half-lives for Y105, Zr106,107, and Mo111, along with β-delayed neutron emission probabilities of Y104, Mo109,110 and upper limits for Y105, Zr103-107, and Mo108,111 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. 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.

  14. {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.

  15. 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.

  16. Unusual shape of pyrrhotite inclusions in scapolite of igneous rocks from the southernern Urals

    NASA Astrophysics Data System (ADS)

    Korinevsky, V. G.; Korinevsky, E. V.

    2016-12-01

    The unique igneous rock (scapolite-diopside gabbro) from the Ilmeny Mountains in the southern Urals is described. Gabbro fills a segment of dike 1.3 m thick that cuts through calcite-dolomite carbonatite. Medium-grain pyroxenite with scapolite that occurs at selvages gradually passes to scapolite-bearing gabbro in the central part of the dike. Scapolite crystals display surfaces of concurrent growth, which are evidence of their magmatic origin. Scapolite (Me 63-70%) contains numerous pyrrhotite inclusions as platelets 0.001 mm thick oriented parallel to the cleavage plane {100}. The calculated pyrrhotite formula is consistent with its stoichiometry (Fe1-xS). The morphology of the platelets (hexagonal sections) and their optical properties indicate a hexagonal symmetry of pyrrhotite. As follows from the insignificant difference between scapolite grains with and without pyrrhotite inclusions, scapolite and pyrrhotite should be regarded as products of synchronous magmatic melt crystallization.

  17. 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.

  18. 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

  19. 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.

  20. 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…

  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.

  2. 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

  3. 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

    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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Histamine H3 receptor antagonists/inverse agonists on cognitive and motor processes: relevance to Alzheimer's disease, ADHD, schizophrenia, and drug abuse.

    PubMed

    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.

  14. 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

  15. Relevance of indirect comparisons in the German early benefit assessment and in comparison to HTA processes in England, France and Scotland.

    PubMed

    Lebioda, Andrea; Gasche, David; Dippel, Franz-Werner; Theobald, Karlheinz; Plantör, Stefan

    2014-12-01

    Early benefit assessment in Germany under the legislative framework of AMNOG (Arzneimittelmarktneuordnungsgesetz) requires direct comparisons of the new drug with appropriate comparators determined by the Federal Joint Committee (G-BA). In case no head-to-head studies are available for direct comparisons, the submission of indirect comparisons is permitted to assess the additional benefit of the new drug. However, the Institute for Quality and Efficiency in Health Care (IQWiG) states a clear preference for head-to-head trials and defines strict requirements for indirect comparisons to be considered in the benefit assessment. Similar requirements also exist in other countries with mandatory health technology assessments (HTA), like France, England and Scotland. Our evaluation shows that a comparison of the different HTA regarding indirect comparisons is difficult. Overall, external preconditions and methodological requirements are demanding and hardly to fulfill by pharmaceutical companies for implementation of indirect comparisons in early benefit assessment. The determination of the appropriate comparators, outcomes, patient subgroups and study choice are the main target within indirect comparisons for the future. To compare and assess submitted indirect comparisons it would be desirable that a transparent process was established, including the mandatory publication of HTA-reports within Europe and international guidelines, accepted by a large number of HTA-agencies.

  16. Searching for the low-energy resonances in the 12C(12C,n)23Mg reaction cross section relevant for s-process nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Bucher, B.; Fang, X.; Almaraz-Calderon, S.; Alongi, A.; Ayangeakaa, A. D.; Beard, M.; Best, A.; Browne, J.; Cahillane, C.; Couder, M.; deBoer, R.; Kontos, A.; Long, A.; Lu, W.; Lyons, S.; Notani, M.; Patel, D.; Paul, N.; Roberts, A.; Robertson, D.; Smith, K.; Stech, E.; Talwar, R.; Tan, W.; Tang, X. D.

    2013-03-01

    The 12C(12C,n) reaction (Q=-2.6 MeV) is a potential neutron source for the weak s-process occurring in shell-carbon burning of massive stars. The uncertainty in this reaction rate limits our understanding of the production of elements in the range 60 < A < 110. Current stellar models must rely on the smooth extrapolation of a dubious statistical model calculation based on experimental data taken at energies well above the Gamow window which lies below 3.2 MeV. At Notre Dame, this reaction cross section has been measured in finer steps at energies above 3.5 MeV, while successful measurements down to 3.1 MeV have just recently been achieved. In addition, a new extrapolation based on measurements of the mirror system has been developed which predicts a number of low-energy resonances while accounting well for the high-energy resonances. An overview of this work along with the most recent results and astrophysical implications are presented.

  17. 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.

  18. Architecture of the Igneous Lower Crust at Oceanic Core Complexes: constraints from IODP Hole U1309D

    NASA Astrophysics Data System (ADS)

    Christofferson, C. A.; Cheadle, M. J.; John, B. E.; Schoolmeesters, N.; Swapp, S. M.; Grimes, C. B.

    2011-12-01

    Slow spreading mid-ocean ridges are a ubiquitous part of the global ridge system, yet remain poorly understood. The crust produced at these ridges is fundamentally different than that produced at fast spreading ridges where the crustal architecture largely conforms to the standard Penrose type crust. At slow spread ridges, a reduced magma supply to the crust allows extensional faulting to play a much more important role in accommodating plate separation than at fast spread ridges. Oceanic core complexes (OCCs), a product of such faulting, denude lower crust to the surface via detachment faulting, and thus provide a means to study the architecture of slow spread lower crust. We report a detailed lithologic analysis of IODP Hole U1309D drilled into the Atlantis Massif OCC (30°N MAR). The abundance of sharp contacts between thin inter-layered gabbroic and ultramafic rocks throughout the core supports crustal construction via small (10-40m thick) injections of magma. Paleomagnetic remanance data allows re-orientation of the observed contacts and igneous fabrics to their original orientation at intrusion, and suggest that most contacts and fabrics were sub-vertical. These data therefore imply that construction of slow spread gabbroic lower crust at OCCs is dominated by dike-like intrusions rather than by sills. Combined U-Pb and (U-Th)/He zircon thermochronometry are used to predict a 3-4km thick zone of accretion that lies 6-7 km below seafloor, at the root of the detachment fault. Existing seismic data estimate the depth of the Moho to be 5km at Atlantis Massif constraining the width of the accretion zone in the footwall of the detachment fault to be 4km. Igneous fabrics from unfaulted gabbroic rocks provide an additional major constraint on the processes occurring within this zone of magmatic accretion. Electron backscatter diffraction (EBSD) was used to characterize the fabrics of slow-spread gabbros from the Atlantis Massif OCC, and other OCCs on the MAR (the 15

  19. A Experimental Study of the Correlation of Process Parameters with YTTRIUM(1) BARIUM(2) COPPER(3) OXIDE(7 - Thin Film Properties Relevant to Microwave Applications.

    NASA Astrophysics Data System (ADS)

    Ihsan, Mojeeb Bin

    1993-01-01

    Superconducting {rm Y_1Ba _2Cu_3O_{7-x}} thin films were deposited by off-axis reactive planar magnetron sputtering for use in passive microwave devices. The effect of process parameters on thin film properties was studied. Targets of two different stoichiometries, viz. { rm Y_1Ba_2Cu_3O_{7 -x}} and {rm Y_1Ba _2Cu_{4.5}O_{y} } were used and thin films were deposited on MgO, SrTiO_3, and LaAlO _3. These films were characterized by four probe dc transport measurement, microwave absorption measurement, SEM, EDS, RBS, and x-ray diffraction. High quality films on all substrates were obtained with in-situ heating. All in-situ films were highly textured with a high degree of c-axis orientation perpendicular to the substrate plane and with a substantial amount of crystallographic and structural order. The dc transport properties of in-situ films were found to be relatively insensitive to target stoichiometry, for a given substrate. Whereas, the surface morphology and microwave properties were found to be dependent upon the target stoichiometry, substrate material and film thickness. Basket weave structure (a-axis grains oriented at 90^ circ with respect to each other) was found to grow on top of c-axis oriented film exhibiting good microwave characteristics in terms of phase purity and weak link behavior. Microwave absorption measurement was found to be a better probe of the uniformity of film properties, and it was possible to detect low Tc phases that were undetectable by dc transport measurement and x-ray diffraction analysis. To test the application of these materials in microwave devices and to study the fundamental aspect of superconductivity, linear microstrip resonators were designed (for lambda_{rm g} /2 resonance near 10 GHz), fabricated from the deposited films and characterized. The best superconducting resonator shows, an unloaded Q of ~1650 at 9.6275 GHz and 35 K. The Q measurements on the microstrip resonators were used to calculate the surface resistivities

  20. Large-scale processes relevant to extreme hot and dry summer conditions in the South Central U.S.: Comparing observations with CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Ryu, J. H.; Hayhoe, K.

    2015-12-01

    In recent years, record high temperatures combined with extreme precipitation deficits have led to record-breaking droughts that have affected the Southern Plains. The 2011 drought and heat wave caused over $12B in damages across the SP region. Here, we combine station data with reanalysis to identify the hottest summers in the last 30 years. Consistent with previous analysis, we find that very hot temperatures over the region are highly correlated both precipitation as well as soil moisture deficits. Atmospheric circulation in the SP region during summer is generally dominated by the North Atlantic Subtropical High (NASH), which extends westward from its winter position over the Atlantic. The anticyclonic circulation could play a role in reducing convective precipitation as well as preventing disturbances from moving into the SP region. Examining the NARR reanalysis for the hottest summers of record, we find that the anticyclonic circulation associated with the NASH extends over the SP region relatively earlier in the summer and results in a comparatively stronger anticyclonic circulation, which in turn seems to be influenced by the large-scale climate variability. Specifically, the negative phase of the Pacific/North American (PNA) teleconnection pattern is characterized by high pressure anomalies across the southeastern and south central U.S. during summer. The two hottest years in the last three decades (1980 and 2011) also correlate with the two strongest negative PNA phases over that time. One of the anticipated impacts of human-induced climate change is the increased risk of hot and potentially dry summers across the SP region. For that reason, we also assess to what extent CMIP5 models are able simulate the large-scale processes that, according to reanalysis, are closely related to extreme hot and dry summer conditions over the Southern Plains. Composite maps of extreme heat years simulated in the models do display a stronger-than-average anticyclonic

  1. 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.

  2. Igneous and metamorphic petrology in the field: a problem-based, writing-intensive alternative to traditional classroom petrology

    NASA Astrophysics Data System (ADS)

    DeBari, S. M.

    2011-12-01

    The Geology Department at Western Washington University (~100 geology majors) offers field and classroom versions of its undergraduate petrology course. This is a one-quarter course (igneous and metamorphic petrology) with mineralogy as a prerequisite. The field version of the course is offered during the three weeks prior to fall quarter and the classroom version is offered in spring quarter. We take 15-20 students around the state of Washington, camping at different outcrop sites where students integrate observational skills, petrologic knowledge, and writing. Petrogenetic associations in various tectonic settings provide the theme of the course. We compare ophiolites vs. arc sequences (volcanic, plutonic, and metamorphic rocks), S- vs. I-type granitoids (plutonic rocks and associated metamorphic rocks), Barrovian vs. Buchan vs. subduction zone metamorphism of different protoliths, and flood-basalt vs. active-arc volcanism. Some basics are covered in the first day at WWU, followed by 17 days of field instruction. Lecture is integrated with outcrop study in the field. For example, students will listen to a lecture about magma differentiation processes as they examine cumulate rocks in the Mt. Stuart batholith, and a lecture about metamorphic facies as they study blueschist facies rocks in the San Juan Islands. Students study multiple outcrops around a site for 1-4 days. They then use their observations (sketches and written descriptions of mineral assemblages, rock types, rock textures, etc.) and analysis techniques (e.g. geochemical data plotting, metamorphic protolith analysis) to write papers in which the data are interpreted in terms of a larger tectonic problem. In advance of the writing process, students use group discussion techniques such as whiteboarding to share their observational evidence and explore interpretations. Student evaluations indicate that despite the intense pace of the course, they enjoy it more. Students also feel that they retain more

  3. 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

  4. 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

  5. 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

  6. The Fractal Nature of Relevance: A Hypothesis.

    ERIC Educational Resources Information Center

    Ottaviani, J. S.

    1994-01-01

    Discusses precision and recall in information science and proposes a new model based on fractal geometry for clusters of relevant documents. Search strategies for retrieving a group of relevant documents are reviewed; fractal sets and chaotic processes are described; and the new model is explained. (Contains 43 references.) (LRW)

  7. 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.

  8. The Limits to Relevance

    NASA Astrophysics Data System (ADS)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  9. Al-in-olivine thermometry evidence for the mantle plume origin of the Emeishan large igneous province

    NASA Astrophysics Data System (ADS)

    Xu, Rong; Liu, Yongsheng

    2016-12-01

    The Emeishan large igneous province (ELIP) is renowned for its world-class Ni-Cu-(PGE) deposits and its link with the Capitanian mass extinction. The ELIP is generally thought to be associated with a deep mantle plume; however, evidence for such a model has been challenged through geology, geophysics and geochemistry. In many large igneous province settings, olivine-melt equilibrium thermometry has been used to argue for or against the existence of plumes. However, this method involves large uncertainties such as assumptions regarding melt compositions and crystallisation pressures. The Al-in-olivine thermometer avoids these uncertainties and is used here to estimate the temperatures of picrites in the ELIP. The calculated maximum temperature (1440 °C) is significantly ( 250 °C) higher than the Al-in-olivine temperature estimated for the average MORB, thus providing compelling evidence for the existence of thermal mantle plumes in the ELIP.

  10. 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.

  11. 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.

  12. The Emplacement of the Newry Igneous Complex, Northern Ireland, from magnetic fabrics and strain

    NASA Astrophysics Data System (ADS)

    Stevenson, C.; Anderson, P.; Cooper, M.; Ellam, R. M.; Reavy, J.; Condon, D. J.; Crowley, Q.

    2013-05-01

    The Newry Igneous Complex (NIC) is a largely granodioritic intrusion, comprising three plutons together with an intermediate-ultramafic body at its NE end. The recent Tellus survey of Northern Ireland has highlighted several geophysical anomalies within this area, including two previously unrecognised concentric aeromagnetic structures. U-Pb zircon ages and a geochemical study suggest that these features represent magmas intruded at different times, and that each pluton was emplaced through a series of inward-younging, concentric pulses. A combination of anisotropy of magnetic susceptibility (AMS) and field relations were used to investigate the emplacement of these pulses. AMS reveals strong, dominantly oblate, concentric fabrics. These suggest forceful emplacement. In detail magnetic anisotropy values are highest near the boundary of internal pulses, suggesting that AMS is recording variations in magmatic strain consistent with a pulsed emplacement in unique detail. Our model for the NIC is that it was emplaced as a ballooning type pluton after ascent through a tectonically created conduit along a deeply penetrating fault.

  13. 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.

  14. 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.

  15. Magnetic fabrics and petrology of the Newry Igneous Complex, Northern Ireland reveals a new emplacement model

    NASA Astrophysics Data System (ADS)

    Anderson, Paul; Stevenson, Carl; Cooper, Mark; Ellam, Rob; Meighan, Ian; Hurley, Colm; Reavy, John; Inman, James; Condon, Dan; Crowley, Quentin

    2013-04-01

    The Newry Igneous Complex (NIC) is a largely granodioritic intrusion, comprising three plutons together with an intermediate-ultramafic body at its NE end. The recent Tellus survey of Northern Ireland has highlighted several geophysical anomalies within this area, including two previously unrecognised concentric aeromagnetic structures. U-Pb zircon ages and a geochemical study suggest that these features represent magmas intruded at different times, and that each pluton was emplaced through a series of inward-younging, concentric pulses. A combination of anisotropy of magnetic susceptibility (AMS) and field relations were used to investigate the emplacement of these pulses. AMS reveals strong, dominantly oblate, concentric fabrics. These suggest forceful emplacement. Field relationships indicate that the complex was intruded as steep, sheet-like pulses. Host rocks show deflection of fabrics around the NIC supporting the forceful emplacemnt model. However the amount of strain recorded in the host rocks does not fully explain the space required for intrusion. The presence of a deeply penetrating tectontic structure offers a way to transport magma and create space through a releasing bend. The releasing bend would have created some of the space for intrusion to take place initially and likely guided the ascent of magma. However, the strong fabrics present within the NIC suggest that most of the space for the intrusion was created in a forceful way. Therefore, the NIC was emplaced as a ballooning type pluton after ascent through a tectonically created conduit along a deeply penetrating fault.

  16. 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.

  17. Seismic volcanostratigraphy of the western Indian rifted margin: The pre-Deccan igneous province

    NASA Astrophysics Data System (ADS)

    CalvèS, GéRôMe; Schwab, Anne M.; Huuse, Mads; Clift, Peter D.; Gaina, Carmen; Jolley, David; Tabrez, Ali R.; Inam, Asif

    2011-01-01

    The Indian Plate has been the focus of intensive research concerning the flood basalts of the Deccan Traps. Here we document a volcanostratigraphic analysis of the offshore segment of the western Indian volcanic large igneous province, between the shoreline and the first magnetic anomaly (An 28 ˜63 Ma). We have mapped the different crustal domains of the NW Indian Ocean from stretched continental crust through to oceanic crust, using seismic reflection and potential field data. Two volcanic structures, the Somnath Ridge and the Saurashtra High, are identified, extending ˜305 km NE-SW in length and 155 km NW-SE in width. These show the internal structures of buried shield volcanoes and hyaloclastic mounds, surrounded by mass-wasting deposits and volcanic sediments. The structures observed resemble seismic images from the North Atlantic and northwest Australia, as well as volcanic geometries described for Réunion and Hawaii. The geometry and internal seismic facies within the volcanic basement suggest a tholeiitic composition and subaerial to shallow marine emplacement. At the scale of the western Indian Plate, the emplacement of this volcanic platform is constrained by structural lineations associated with rifting. By reviewing the volcanism in the Indian Ocean and plate reconstruction of the area, the timing of the volcanism can be associated with eruption of a pre-Deccan continental flood basalt (˜75-65.5 Ma). The volcanic platform in this study represents an addition of 19-26.5% to the known volume of the West Indian Volcanic Province.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Determination and distribution of diesel components in igneous rock surrounding underground diesel storage facilities in Sweden.

    PubMed

    Loren, A; Hallbeck, L; Pedersen, K; Abrahamsson, K

    2001-01-15

    In Sweden, a preliminary investigation of the contamination situation of igneous rock surrounding underground storage facilities of diesel showed that the situation was severe. The diesel was believed to have penetrated into the rock as far as 50 m from the walls of the vaults. Consequently, the risk for contamination of groundwater and recipients could not be neglected. To be able to assess the fate of diesel components in rock, both a suitable drilling method and a method for the determination of a wide range of diesel components were needed. The analytical method presented made it possible to quantify a number of hydrocarbons in rock samples collected with triple-tube core drilling. The samples were dissolved in hydrofluoric acid (HF) with hexane in Teflon centrifuge tubes. After digestion of the rock, extraction of the analytes with hexane was performed. Determination of the individual hydrocarbons present was done with gas chromatography-mass spectrometry (GC-MS). The method was used to study the environmental impact of the underground storage of diesel. The drilling method enabled sampling without contamination risks. Our data show that the major transport of diesel components in rock occurs through fracture systems and that diffusion of diesel through the rock is of minor importance. The results have drastically changed the view of the contamination situation of diesel in the vicinity of storage facilities in hard rock in Sweden.

  8. Establishment of an empirical correlation for estimating the thermal conductivity of igneous rocks

    SciTech Connect

    Garcia, A.; Contreras, E. ); Viggiano, J.C. )

    1989-09-01

    A correlation to predict the thermal conductivity of andesitic igneous rocks is developed from measured data on drill cores from wells from the Los Azufres geothermal field, Mexico. The correlation was developed from density, porosity, and thermal conductivity. Seventeen determinations were made on drill cores extracted at varying depths from 12 wells. Thermal conductivity varied from 1.05 to 2.34 W {center dot} m{sup {minus}1} {center dot} K{sup {minus}1}, while bulk density varied from 2,050 to 2,740 kg {center dot} m{sup {minus}3} and grain density varied from 2,610 to 2,940 kg {center dot} m{sup {minus}3}. Total porosity varied from 1.9 to 24.7%. Two polynomial regressions, one linear and one quadratic, were tested on the thermal conductivity-times-bulk density product, with total porosity as the independent variable. The correlation coefficients and residual mean square deviations were 0.83 and 0.00491 for the linear fit and 0.87 and 0.00425 for the quadratic model, respectively. For porosities up to about 18%, both models showed very close predictions, but for larger values, the quadratic model appeared to be better and it is recommended for the porosity range from 0 to 25%. Furthermore, density and porosity may be determined from drill cuttings, which are more readily available than cores.

  9. Anionic constitution of 1-atmosphere silicate melts: implications for the structure of igneous melts.

    PubMed

    Virgo, D; Mysen, B O; Kushiro, I

    1980-06-20

    A structural model is proposed for the polymeric units in silicate melts quenched at 1 atmosphere. The anionic units that have been identified by the use of Raman spectroscopy are SiO(4)(4-) monomers, Si(2)O(7)(6-) dimers, SiO(3)(2-) chains or rings, Si(2)O(5)(2-) sheets, and SiO(2) three-dimensional units. The coexisting anionic species are related to specific ranges of the ratio of nonbridging oxygens to tetrahedrally coordinated cations (NBO/Si). In melts with 2.0 < NBO/Si < approximately 4.0, the equilibrium is of the type [See equation in the PDF file]. In melts with NBO/Si approximately 1.0 to 2.0, the equilibrium anionic species are given by [See equation in the PDF file]. In alkali-silicate melts with NBO/Si <~ 1.3 and in aluminosilicate melts with NBO/T < 1.0, where T is (Si + Al), the anionic species in equilibrium are given by [See equation in the PDF file]. In multicomponent melts with compositions corresponding to those of the major igneous rocks, the anionic species are TO(2), T(2)O(5), T(2)O(6), and TO(4), and the coexisting polymeric units are determined by the second and third of these disproportionation reactions.

  10. The importance of late- and post-orogenic crustal growth in the early Proterozoic: Evidence from Sm-Nd isotopic studies of igneous rocks in the Makkovik Province, Canada

    NASA Astrophysics Data System (ADS)

    Kerr, Andrew; Fryer, Brian J.

    1994-07-01

    Sm-Nd isotopic studies suggest that large tracts of 1900-1700 Ma old crust in Laurentia-Baltica is of 'juvenile' origin. This crust has generally been ascribed to arc magmatism, sustained over long periods, and most conceptual models for crustal growth emphasize this process. The late- to post-orogenic granitoid rocks that areally dominate many ancient orogenic belts are commonly viewed as anatectic derivatives of the earlier arc-type crust. However, in regions of short crustal residence, the time resolution of isotopic tracers, such as the Sm-Nd system, does not permit discrimination between this model and continued growth of the crust during post-orogenic magmatism. The relative contributions of recycled crust and new, mantle-derived material in late- to post-orogenic magmas can only be assessed where they also transect much older crustal blocks. The Nd isotopic signatures of 1800-1720 Ma igneous suites in the Makkovik Province define such a boundary between an Archean craton and a juvenile Proterozoic domain. In the juvenile domain, the Nd signatures of most igneous suites are equivocal (initial epsilon(sub Nd) = 0 to +2), and they could be anatectic derivatives of slightly older orthogneisses; however, addition of new, mantle-derived material is documented by 'A-type' granites with initial epsilon(sub Nd) up to +4. In the cratonic domain, temporally and compositionally equivalent igneous suites mostly have initial epsilon(sub Nd) of -7 to -3, significantly above local Archean basement, which has epsilon(sub Nd) of -15 at 1800 Ma. Conservative calculations suggest that most of these suites contain more than 50% new, mantle-derived material. These results suggest significant crustal growth via late-stage magmatism, and direct interaction of mantle-derived magmas and lower crustal rocks. In contrast, 1650 Ma igneous suites lack clear systematic variation in epsilon(sub Nd), and are interpreted as representing crustal growth via later, distal, arc-type magmatism

  11. 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)

  12. 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…

  13. 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…

  14. 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.

    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.

  15. Multiple Mechanisms of Transient Heating Events in the Protoplanetary Disk: Evidence from Precursors of Chondrules and Igneous Ca,Al-Rich Inclusions

    NASA Astrophysics Data System (ADS)

    Krot, A. N.; Nagashima, K.; Libourel, G.; Miller, K. E.

    2017-02-01

    Here we review the mineralogy, petrography, O-isotope compositions, and trace element abundances of precursors of chondrules and igneous CAIs which provide important constraints on the mechanisms of transient heating events in the protoplanetary disk.

  16. 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.

  17. Paleomagnetic directional groups and paleointensity from the flood basalt in the Tarim large igneous province: implications for eruption frequency

    NASA Astrophysics Data System (ADS)

    Usui, Yoichi; Tian, Wei

    2017-01-01

    We present paleomagnetic secular variation and paleointensity from the Early Permian Tarim large igneous province, NW China. The studied sections comprise a total of 400 m of basaltic flows. Paleomagnetic directions were determined for 11 flows. Four successive flows with a cumulative thickness of 150 m showed a statistically identical paleomagnetic direction. Assuming a paleosecular variation speed similar to that of the present day, the 150-m-thick basalt was estimated to have erupted within the past few centuries. Paleointensity experiments were performed on both whole-rock and single plagioclase samples. Although alterations during the experiment and/or weak remanence degraded the data quality, the flows with the same paleomagnetic direction revealed similar paleointensity estimates, supporting the hypothesis that the eruption of these flows was rapid. More generally, flows from the Lower Kupukuziman Formation seem to record lower paleointensity compared to flows from the overlying Kaipaizileike Formation. [Figure not available: see fulltext. Caption: Left the extent of the Tarim large igneous province. Center in-situ paleomagnetic directions obtained from the Tarim large igneous province. Subashi and Yingan represents directions reported in a previous research. Right tilt-corrected paleomagnetic directions. Tight clustering of the direction indicate fast eruption relative to the paleomagnetic secular variation (PSV) speed.

  18. 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.

  19. 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

  20. Microdosing: concept, application and relevance.

    PubMed

    Tewari, Tushar; Mukherjee, Shoibal

    2010-04-01

    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.

  1. 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

  2. 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

  3. Prospecting for Diverse Igneous Rock Types on Mars: Pixl on "black Beauty" Nwa 7533

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Flannery, D.; Allwood, A.; Thompson, D. R.; Hodyss, R. P.; Clark, B. C.; Elam, W. T.; Hurowitz, J.

    2015-12-01

    In order to understand the evolution of the Martian crust and mantle, we need to acquire and analyze samples of igneous rocks other than the basaltic and ultramafic lithologies represented by the majority of Martian meteorites. Recent results from the Curiosity Rover demonstrate that diverse rock types exist in some Martian sedimentary environments in the form of conglomerate components or float, some of which shed light on the nature of early Martian crust (e.g., Sautter et al., 2015). We are developing investigation strategies for the in-situ instruments that will be flown on the Mars 2020 rover. These instruments will be used to inform the sampling campaigns required for future sample return missions. To achieve this, we applied PIXL (Planetary Instrument for X-ray Lithochemistry), an instrument for the Mars 2020 rover mission, to the meteorite NWA 7533. This meteorite is a pairing of NWA 7034, known informally as "Black Beauty", a new type of Martian meteorite that is broadly similar to the average composition of the Martian crust. This type of meteorite is essentially a 'conglomerate', with many diverse rock types, including mafic, feldspathic, and exotic rock fragments such as feldspar-ilmenite-phosphate clasts, as observed using higher-spatial resolution and higher sensitivity laboratory instruments (e.g., Agee et al., 2013; Humayun et al., 2014; Santos et al., 2015). Using PIXL, we analyzed a mm-scale cut and polished surface and applied algorithms developed by the PIXL team to semi-autonomously define and group regions containing similar lithological components (Thompson et al., 2015). PIXL data rapidly reveal distinctive zircon-bearing lithologies and feldspar-ilmenite-phosphate clasts similar to the detailed petrographic and mineralogical observations. Results suggest that PIXL readily identifies lithologies with minerals and elements (e.g., Rb and Sr) that are important for geochronology studies.

  4. 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.

  5. 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.

  6. 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).

  7. Igneous petrology of the new ureilites Nova 001 and Nullarbor 010

    NASA Astrophysics Data System (ADS)

    Triman, Allan H.; Berkley, John L.

    1994-11-01

    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.

  8. 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.

  9. Tectonic significance of Neoproterozoic magmatism of Nakora area, Malani igneous suite, Western Rajasthan, India

    NASA Astrophysics Data System (ADS)

    Kumar, Naresh; Vallinayagam, G.

    2014-05-01

    Three magmatic phases are distinguished in the Neoproterozoic Nakora Ring Complex (NRC) of Malani Igneous Suite (MIS), namely (a) Extrusive (b) Intrusive and (c) Dyke phase. Magmatism at NRC initiated with minor amount of (basic) basalt flows and followed by the extensive/voluminous acid (rhyolites-trachytes) flows. The ripple marks are observed at the Dadawari area of NRC in tuffaceous rhyolite flow which suggests the aqueous condition of flows deposition. The emplacement of the magma appears to have been controlled by a well defined NE-SW tectonic lineament and cut by radial pattern of dykes. These NE-SW tectonic lineaments are the linear zones of crustal weakness and high heat flow. The spheroidal and rapakivi structures in the Nakora acid volcanics indicate the relationship between genetic link and magma mixing. Basalt-trachyte-rhyolite association suggests that the large amount of heat is supplied to the crust from the magma chamber before the eruption. The field (elliptical/ring structures), mineralogical and geochemical characteristics of Nakora granites attest an alkaline character in their evolution and consistent with within plate tectonic setting. The emplacement of these granites and associated volcanics is controlled by ring structures, a manifestation of plume activity and cauldron subsidence, an evidence of extensional tectonic environment. NRC granites are the product of partial melting of rocks similar to banded gneiss from Kolar Schist Belt of India. The present investigations suggest that the magmatic suites of NRC rocks are derived from a crustal source and the required heat supplied from a mantle plume.

  10. 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.

  11. Alkaline igneous rocks of Magnet Cove, Arkansas: Mineralogy and geochemistry of syenites

    USGS Publications Warehouse

    Flohr, M.J.K.; Ross, M.

    1990-01-01

    Syenites from the Magnet Cove alkaline igneous complex form a diverse mineralogical and geochemical suite. Compositional zoning in primary and late-stage minerals indicates complex, multi-stage crystallization and replacement histories. Residual magmatic fluids, rich in F, Cl, CO2 and H2O, reacted with primary minerals to form complex intergrowths of minerals such as rinkite, fluorite, V-bearing magnetite, F-bearing garnet and aegirine. Abundant sodalite and natrolite formed in pegmatitic segregations within nepheline syenite where Cl- and Na-rich fluids were trapped. During autometasomatism compatible elements such as Mn, Ti, V and Zr were redistributed on a local scale and concentrated in late-stage minerals. Early crystallization of apatite and perovskite controlled the compatible behavior of P and Ti, respectively. The formation of melanite garnet also affected the behaviour of Ti, as well as Zr, Hf and the heavy rare-earth elements. Pseudoleucite syenite and garnet-nepheline syenite differentiated along separate trends, but the two groups are related to the same parental magma by early fractionation of leucite, the presumed precursor of intergrowths of K-feldspar and nepheline. The Diamond Jo nepheline syenite group defines a different differentiation trend. Sphene-nepheline syenite, alkali syenite and several miscellaneous nepheline syenites do not consistently plot with the other syenite groups or each other on element and oxide variation diagrams, indicating that they were derived from still other parental syenite magmas. Mineral assemblages indicate that relatively high f{hook};O2, at or above the fayalite-magnetite-quartz buffer, prevailed throughout the crystallization history of the syenites. ?? 1990.

  12. Land Bridges and Oceanic Gateways: the Importance of Large Igneous Provinces in Reconstructing Paleobathymetry

    NASA Astrophysics Data System (ADS)

    Whittaker, J. M.; Seton, M.; Cooper, A.

    2015-12-01

    Accurate reconstructions of global and regional paleobathymetry are important for understanding changing patterns of paleo-ocean circulation and climate over geological timescales. Large Igneous Provinces (LIPs) have erupted throughout the world's oceans, creating important bathymetric expressions on the seafloor and temporally exposed land. Global plate tectonic reconstructions of mid-ocean ridges, LIPs, and plumes have demonstrated that the formation of LIPs repeatedly occur at specific ridge-plume interaction locations over periods of tens of millions of years. Due to the shallow depth of mid-ocean ridges relative to the abyssal plains, the formation of LIPs at these locations increases the likelihood of the creation of sub-aerial regions that exist for millions of years before subsiding. Here, we assess the time-varying size, shape, location and depth of LIPs globally and incorporate them into maps of predicted paleo-bathymetry. We focus on accurate estimation of the paleo-bathymetry of oceanic LIPs by taking into account the temporal plume swell that affects the wider region around each LIP, with a likely significant affect on the surface height of both onshore and offshore regions. We ground truth our estimations using a variety of marine data, particularly results from ocean drilling. Of particular interest is the present-day southern Indian Ocean (offshore eastern Antarctica) where the Bouvet, Marion and Kerguelen plumes interact with the Southwest Indian mid-ocean ridge. As West Gondwana broke apart, continental Antarctica slowly moved away from this stationary line of ridge-plume interactions, with the newly formed oceanic crust of the southern Indian and Atlantic Oceans overlying these locations instead. Thus, since the Jurassic parts of East Antarctica and the adjacent Atlantic and Indian oceans have been repeatedly affected by the formation of LIPs at ridge-plume interactions, and our results suggest the potential for landbridges or significant islands

  13. 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.

  14. 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.

  15. 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.

  16. 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 formation contacts subdivided the overburden into thin mechanical layers that slipped over one another during doming. Measurements of outcrop-scale fault populations at the three mountains reveal a network of faults that strikes at high angles to sedimentary beds which themselves strike tangentially about the domes. These faults have normal and reverse components of slip that accommodated bending and stretching strains within the strata. An early stage of this deformation is displayed at Mount Holmes, where states of stress computed from three fault samples correlate with the theoretical distribution of stresses resulting from bending of thin, circular, elastic plates. Field observations and analysis of frictional driving stresses acting on horizontal planes above an opening-mode dislocation, as well as the paleostress analysis of faulting, indicate that bedding-plane slip and layer flexure were important components of the early deformation. As the amplitude of doming increased, radial and circumferential stretching of the strata and rotation of the older faults in the steepening limbs of the domes increased the complexity of the fault patterns. Steeply-dipping, map-scale faults with dip-slip displacements indicate a late-stage jostling of major blocks over the central

  17. 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.

  18. Stress Activation and Propagation of Electronic Charge Carriers in Igneous Rocks

    NASA Astrophysics Data System (ADS)

    Ling, J.; Freund, F. T.

    2007-12-01

    Igneous and high-grade metamorphic rocks in the Earth's crust generate electric currents when subjected to deviatoric stresses. The reason is that these rocks contain dormant electronic charge carriers in the form of peroxy links. Peroxy links are sites in the crystal structures of the constituent minerals where oxygen anions have converted from their common 2- valence state to the 1- valence state, O3X-OO-XO3 with X=Si4+, Al3+ etc. As rocks are stressed and dislocations sweep through the mineral grains, the peroxy links break up, activating electrons and pholes ("phole" is an abbreviation for "positive hole", a defect electron on the oxygen sublattice, chemically O- in a matrix of O2-). The pholes are mobile electronic charge carriers that can spread out of the stressed rock into the surrounding unstressed rock. They travel via energy levels at the upper edge of the valence bands, cross grain boundaries and achieve a phase velocity on the order of 200±50 m/sec, consistent with phonon-assisted electron hopping. Due to mutual repulsion inside the rock volume the pholes spread to the surface, where they build up a positive surface charge. The surface charge can be measured with a non-contact capacitive sensor. If a Cu contact is applied to the surface of the rock, electrons are injected from ground into the rock in response to the evolving positive charge on the rock surface. We modeled surface potentials and burst-like electron injections following low and medium velocity impact experiments, 100 m/sec and 1.5 km/sec respectively.

  19. The ca. 1380 Ma Mashak igneous event of the Southern Urals

    NASA Astrophysics Data System (ADS)

    Puchkov, Victor N.; Bogdanova, Svetlana V.; Ernst, Richard E.; Kozlov, Vjacheslav I.; Krasnobaev, Arthur A.; Söderlund, Ulf; Wingate, Michael T. D.; Postnikov, Alexander V.; Sergeeva, Nina D.

    2013-08-01

    A review of the geochronology, geochemistry and distribution of the 1380 Ma Mashak Large Igneous Province (LIP) of the eastern margin of the East European craton indicates a potential link to a major breakup stage of the Mesoproterozoic supercontinent Columbia (Nuna), link to a major stratigraphic boundary (Lowe-Middle Riphean), and economic significance for hydrocarbons and metallogeny. Specifically, the Mashak event likely has much greater extent than previously realized. Two U-Pb baddeleyite (ID TIMS) age determinations on dolerite sills obtained from borehole (Menzelinsk-Aktanysh-183) confirm the western extent of the Mashak event into the crystalline basement of the East European Craton (1382 ± 2 Ma) and into the overlying Lower Riphean sediments (1391 ± 2 Ma), and the imprecise ages reported elsewhere indicate the possible extension into the Timan region, with an overall areal extent of more than 500,000 km2 (LIP scale). It has tholeiitic compositions and is associated with breakup on the eastern margin of the craton - in addition, precise SHRIMP zircon ages of 1386 ± 5 Ma and 1386 ± 6 Ma (this paper) provide confirmation of previous approximate 1380-1383 Ma zircon age determination of the same formation, and suggest an age of ca. 1.4 Ga for the Lower/Middle Riphean boundary which was formerly considered to be 1350 ± 10 Ma. Contemporaneous magmatic rocks in the northeastern Greenland part of Laurentia (Zig-Zag Dal and Midsommerso formations) and Siberia (Chieress dykes and other dolerites) together with the Mashak event are suggested to be fragments of a single huge LIP and to correspond to breakup stage of the Columbia (Nuna) supercontinent. The Mashak LIP also has some significance, at least in Volgo-Uralia, for hydrocarbons and metallogeny.

  20. Plagioclase preferred orientation and induced seismic anisotropy in mafic igneous rocks

    NASA Astrophysics Data System (ADS)

    Ji, Shaocheng; Shao, Tongbin; Salisbury, Matthew H.; Sun, Shengsi; Michibayashi, Katsuyoshi; Zhao, Weihua; Long, Changxing; Liang, Fenghua; Satsukawa, Takako

    2014-11-01

    Fractional crystallization and crystal segregation controlled by settling or floating of minerals during the cooling of magma can lead to layered structures in mafic and ultramafic intrusions in continental and oceanic settings in the lower crust. Thus, the seismic properties and fabrics of layered intrusions must be calibrated to gain insight into the origin of seismic reflections and anisotropy in the deep crust. To this end, we have measured P and S wave velocities and anisotropy in 17 plagioclase-rich mafic igneous rocks such as anorthosite and gabbro at hydrostatic pressures up to 650 MPa. Anorthosites and gabbroic anorthosites containing >80 vol% plagioclase and gabbros consisting of nearly equal modal contents of plagioclase and pyroxene display distinctive seismic anisotropy patterns: Vp(Z)/Vp(Y) ≥ 1 and Vp(Z)/Vp(X) ≥ 1 for anorthosites while 0.8 < Vp(Z)/Vp(Y) ≤ 1 and 0.8 < Vp(Z)/Vp(X) ≤ 1 for gabbros. Amphibolites lie in the same domain as gabbros, but show a significantly stronger tendency of Vp(X) > Vp(Y) than the gabbros. Laminated anorthosites with Vp(X) ≈ Vp(Y) ≪ Vp(Z) display a strong crystal preferred orientation (CPO) of plagioclase whose (010) planes and [100] and [001] directions parallel to the foliation. For the gabbros and amphibolites characterized by Vp(X) ≈ Vp(Y) > Vp(Z) and Vp(X) > Vp(Y) > Vp(Z), respectively, pyroxene and amphibole play a dominant role over plagioclase in the formation of seismic anisotropy. The Poisson's ratio calculated using the average P and S wave velocities from the three principal propagation-polarization directions (X, Y, and Z) of a highly anisotropic anorthosite cannot represent the value of a true isotropic equivalent. The CPO-induced anisotropy enhances and decreases the foliation-normal incidence reflectivity at gabbro-peridotite and anorthosite-peridotite interfaces, respectively.

  1. Development of In Vitro-In Vivo Correlation for Amorphous Solid Dispersion Immediate-Release Suvorexant Tablets and Application to Clinically Relevant Dissolution Specifications and In-Process Controls.

    PubMed

    Kesisoglou, Filippos; Hermans, Andre; Neu, Colleen; Yee, Ka Lai; Palcza, John; Miller, Jessica

    2015-09-01

    Although in vitro-in vivo correlations (IVIVCs) are commonly pursued for modified-release products, there are limited reports of successful IVIVCs for immediate-release (IR) formulations. This manuscript details the development of a Multiple Level C IVIVC for the amorphous solid dispersion formulation of suvorexant, a BCS class II compound, and its application to establishing dissolution specifications and in-process controls. Four different 40 mg batches were manufactured at different tablet hardnesses to produce distinct dissolution profiles. These batches were evaluated in a relative bioavailability clinical study in healthy volunteers. Although no differences were observed for the total exposure (AUC) of the different batches, a clear relationship between dissolution and Cmax was observed. A validated Multiple Level C IVIVC against Cmax was developed for the 10, 15, 20, 30, and 45 min dissolution time points and the tablet disintegration time. The relationship established between tablet tensile strength and dissolution was subsequently used to inform suitable tablet hardness ranges within acceptable Cmax limits. This is the first published report for a validated Multiple Level C IVIVC for an IR solid dispersion formulation demonstrating how this approach can facilitate Quality by Design in formulation development and help toward clinically relevant specifications and in-process controls.

  2. 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

  3. Models of single-stage concomitant potassium-argon exchange: an interpretation of discordant whole rock K-Ar data from hydrothermally altered igneous rocks of the South Pennine Orefield, U.K.

    NASA Astrophysics Data System (ADS)

    Mitchell, J. G.; Ineson, P. R.

    1988-04-01

    A model of single-stage concomitant potassium and argon exchange is advanced to explain the existence of rectilinear "isochrons" in potassium-argon correlation diagrams produced from suites of altered rocks. Negative isochron intercepts are shown to be a consequence of fractional argon loss which exceeds potassium loss, and it is demonstrated that no information of immediate geological significance can be obtained from the gradient of such an isochron. Bounds to the "primary formation age" and "age of exchange event" may be established using extreme values of the observed potassium content and from estimates based on the inferred petrology and chemistry of the unaltered rock and/or its alteration products. Ten Carboniferous igneous units from the South Pennine Orefield (involving-thirty-eight independent samples) are investigated by means of the model and eight of the units are consistent with a model of potassium and argon exchange occurring in earliest Mesozoic times (ca. 200 Ma). It is argued that this conclusion augments the already substantial body of evidence for an identifiable widespread igneous and hydrothermal province associated with early rifting processes in the North Atlantic.

  4. "Fingerprinting" tectono-magmatic provenance using trace elements in igneous zircon

    NASA Astrophysics Data System (ADS)

    Grimes, C. B.; Wooden, J. L.; Cheadle, M. J.; John, B. E.

    2015-12-01

    Over 5300 recent SHRIMP-RG analyses of trace elements (TE) in igneous zircon have been compiled and classified based on their original tectono-magmatic setting to empirically evaluate "geochemical fingerprints" unique to those settings. Immobile element geochemical fingerprints used for lavas are applied with the same rational to zircon, including consideration of mineral competition on zircon TE ratios, and new criteria for distinguishing mid-ocean ridge (MOR), magmatic arc, and ocean island (and other plume-influenced) settings are proposed. The elemental ratios in zircon effective for fingerprinting tectono-magmatic provenance are systematically related to lava composition from equivalent settings. Existing discrimination diagrams using zircon U/Yb versus Hf or Y do not distinguish TE-enriched ocean island settings (i.e., Iceland, Hawaii) from magmatic arc settings. However, bivariate diagrams with combined cation ratios involving U-Nb-Sc-Yb-Gd-Ce provide a more complete distinction of zircon from these settings. On diagrams of U/Yb versus Nb/Yb, most MOR, ocean island, and kimberlite zircon define a broad "mantle-zircon array"; arc zircon defines a parallel array offset to higher U/Yb. Distinctly low U/Yb ratios of MOR zircon (typically <0.1) mirror their parental magmas and long-term incompatible element depletion of the MORB mantle. Plume-influenced sources are distinguished from MOR by higher U/Yb, U/Nb, Nb/Yb, and Nb/Sc. For zircon with U/Yb > 0.1, high Sc/Yb separates arc settings from low-Sc/Yb plume-influenced sources. The slope of scandium enrichment trends in zircon differ between MOR and continental arc settings, likely reflecting the involvement of amphibole during melt differentiation. Scandium is thus also critical for discriminating provenance, but its behavior in zircon probably reflects contrasting melt fractionation trends between tholeiitic and calc-alkaline systems more than compositional differences in primitive magmas sourced at each

  5. Is the West Karmøy complex igneous or metasedimentary?

    NASA Astrophysics Data System (ADS)

    Rodgers, John

    1994-03-01

    The island of Karmøy in southwestern Norway is famous among geologists for the Ophiolite, one of the first ophiolites to be recognized and described in the Scandinavian Caledonides. Much of the island is underlain by the West Karmøy Complex, presently interpreted as an igneous complex that intrudes the Karmøy Ophiolite. There is a striking resemblance of some rocks of the Complex with the Sykesville "granite" of Maryland, which was shown by Cloos and by Hopson (1964) to be a metadiamictite. After local examination of the rocks and after comparison with the 1980 report of Ledru, the conclusion was drawn that — except for the Risdal granodiorite, pegmatite and aplite dikes — the Complex is a metasedimentary, compositionally variable succession of meta-arkose (the "quartz-augen gneiss"—Ledru's Diorite quartzique et Granodiorite du nord) and metadiamictite (his various inclusion-rich "granite" units). Both units were derived by erosion from advancing thrust sheets, including the Karmøy Ophiolite, which then overrode the sedimentary succession. The high modal quartz and normative corundum contents of the "granitic" rocks resemble those of the Sykesville and favor a metasedimentary origin; the chemistry is also similar and rather far from a granite minimum melt, though certain mixtures of quartz-sandy matrix and mafic blocks may have melted locally while being overridden by the Ophiolite. Reports that quartz diorite of the West Karmøy Complex intrudes metagabbro of the Karmøy Ophiolite could not be confirmed, although trondhjemite dikes belonging to the Ophiolite do intrude the metagabbro; the contact of the Ophiolite with the Complex was faulted wherever observed. As recognized by almost all observers, both Ophiolite and Complex are overlain unconformably by Upper Ordovician sediments of the Skudeneset Group, which was later deformed and metamorphosed in the greenschist facies; at least a great part of the fault separating the Karmøy Ophiolite and the West

  6. Creep of mafic dykes infiltrated by melt in the lower continental crust (Seiland Igneous Province, Norway)

    NASA Astrophysics Data System (ADS)

    Degli Alessandrini, G.; Menegon, L.; Malaspina, N.; Dijkstra, A. H.; Anderson, M. W.

    2017-03-01

    A dry mafic dyke from a continental lower-crustal shear zone in the Seiland Igneous Province (northern Norway) experienced syn-kinematic melt-rock interaction. Viscous shearing occurred at T ≈ 800 °C, P ≈ 0.75-0.95 GPa and was coeval with infiltration of felsic melt from adjacent migmatitic metapelites. The dyke has a mylonitic microstructure where porphyroclasts of orthopyroxene, clinopyroxene and plagioclase are wrapped by a fine-grained (4-7 μm) polyphase mixture of clinopyroxene + orthopyroxene + plagioclase + quartz + ilmenite ± K-feldspar ± apatite. Microstructural observations and electron backscatter diffraction analysis indicate that the porphyroclasts deformed by a combination of dislocation glide and fracturing, with only a limited record of dislocation creep, recovery and dynamic recrystallization. We identified diffusion creep as the dominant deformation mechanism in the mixture based on the small grain size, phase mixing and weak crystallographic preferred orientation of all phases (interpreted as the result of oriented grain growth during viscous flow). The polyphase mixture did not form by dynamic recrystallization or by mechanical fragmentation of the porphyroclasts, but rather by melt-rock interaction. Thermodynamic models indicate that the syn-kinematic mineral assemblage results from the chemical interaction between a pristine mafic dyke and ca. 10 vol.% of felsic melt infiltrating from the adjacent partially molten metapelites. Extrapolation of laboratory-derived flow laws to natural conditions indicates that the formation of interconnected layers of fine-grained reaction products deforming by diffusion creep induces a dramatic weakening in the mafic granulites, with strain rates increasing up to 2-3 orders of magnitude. The reaction weakening effect is more efficient than the weakening associated with melt-assisted diffusion creep in the presence of up to 10 vol.% of infiltrated melt without formation of fine-grained reaction products

  7. Diffusion effects on oxygen isotope temperatures of slowly cooled igneous and metamorphic rocks

    NASA Astrophysics Data System (ADS)

    Giletti, Bruno J.

    1986-03-01

    Recently obtained data on oxygen diffusion in feldspars, quartz, and hornblende permit the prediction of the apparent 18O 16O temperatures that would be measured in a rock that consisted only of those three minerals, and cooled slowly from high temperature. The computed temperatures would be based on the differences in the 18O 16O ratios between coexisting pairs of minerals. The present calculation takes into account the diffusion rates for oxygen as a function of temperature, the cooling rate of the rock, the mineral grain sizes, and the mode of the rock. For mineral grains 1 mm in radius, and a cooling rate of 10°C/m.y., the minimum difference in apparent temperature between quartz-feldspar and feldspar-hornblende pairs will be 115°C, despite the assumption of a normal, uneventful, slow cooling history to room temperature. Further, the apparent quartz-hornblende temperature will range over 30°C (590-620°C) depending on the mode of the rock. For a cooling rate of 1000°C/m.y., the apparent difference in temperature can be as much as 400°C. Consequently, consistency in temperatures obtained by oxygen isotope analysis should not be expected in most high-grade metamorphic rocks or igneous rocks which are cooled slowly. Departures from the pattern of temperatures obtained in this model would imply a very rapid quench from high temperature, or a complex history for the rock. For some minerals, including hornblende, the relation between temperature and the equilibrium fractionation of oxygen isotopes between coexisting phases has been derived from observed relations in natural specimens. The choice of the specimens used for such calibrations needs to be re-evaluated in light of these findings. This may result in a change in the equilibrium equation constants. An example from the literature, the San Jose tonalite, Baja California, Mexico, was modelled and yields δ 18O concentrations in the minerals that correspond closely with the measured values. This suggests

  8. Let's Get Relevant

    ERIC Educational Resources Information Center

    Liao, T.; Piel, E. J.

    1970-01-01

    Describes a laboratory science course, The Man-Made World, designed for senior high school students who are not science or engineering career oriented. Emphasizes man-machine interaction and decision making processes through modeling and optimizing. Contends that the areas of "information and materials processing should be understood to some…

  9. Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples

    NASA Astrophysics Data System (ADS)

    Miyazaki, Takashi; Vaglarov, Bogdan Stefanov; Takei, Masakazu; Suzuki, Masahiro; Suzuki, Hiroaki; Ohsawa, Kouzou; Chang, Qing; Takahashi, Toshiro; Hirahara, Yuka; Hanyu, Takeshi; Kimura, Jun-Ichi; Tatsumi, Yoshiyuki

    A fully automated open-column resin-bed chemical-separation system, named COLUMNSPIDER, has been developed. The system consists of a programmable micropipetting robot that dispenses chemical reagents and sample solutions into an open-column resin bed for elemental separation. After the initial set up of resin columns, chemical reagents, and beakers for the separated chemical components, all separation procedures are automated. As many as ten samples can be eluted in parallel in a single automated run. Many separation procedures, such as radiogenic isotope ratio analyses for Sr and Nd, involve the use of multiple column separations with different resin columns, chemical reagents, and beakers of various volumes. COLUMNSPIDER completes these separations using multiple runs. Programmable functions, including the positioning of the micropipetter, reagent volume, and elution time, enable flexible operation. Optimized movements for solution take-up and high-efficiency column flushing allow the system to perform as precisely as when carried out manually by a skilled operator. Procedural blanks, examined for COLUMNSPIDER separations of Sr, Nd, and Pb, are low and negligible. The measured Sr, Nd, and Pb isotope ratios for JB-2 and Nd isotope ratios for JB-3 and BCR-2 rock standards all fall within the ranges reported previously in high-accuracy analyses. COLUMNSPIDER is a versatile tool for the efficient elemental separation of igneous rock samples, a process that is both labor intensive and time consuming.

  10. A review of scientific literature examining the mining history, geology, mineralogy, and amphibole asbestos health effects of the Rainy Creek igneous complex, Libby, Montana, USA.

    PubMed

    Bandli, Bryan R; Gunter, Mickey E

    2006-11-01

    This article reviews the past 90 yr of scientific research directed on multiple aspects of the unique geology and environmental health issues surrounding the vermiculite deposit found at Libby, MT. Hydrothermal alteration and extensive weathering of the ultramafic units resulted in the formation of a rich deposit of vermiculite that was mined for 67 yr and used in numerous consumer products in its expanded form. Later intrusions of alkaline units caused hydrothermal alteration of the pyroxenes, resulting in formation of amphiboles. Some of these amphiboles occur in the asbestiform habit and have been associated with pulmonary disease in former miners and mill workers. Identification of these amphibole asbestos minerals has received little attention in the past, but recent work shows that the majority of the amphibole mineral species present may not be any of the amphibole species currently regulated by government agencies. Epidemiological studies on former miners have, nevertheless, shown that the amphibole asbestos from the Rainy Creek igneous complex is harmful; also, a recent study by the Agency for Toxic Substances and Disease Registry shows that residents of Libby who had not been employed in the vermiculite mining or milling operations also appear to have developed asbestos-related pulmonary diseases at a higher rate than the general public elsewhere. Since November 1999, the U.S. Environmental Protection Agency has been involved in the cleanup of asbestos-contaminated sites in and around Libby associated with the mining and processing of vermiculite.

  11. The Ezhimala Igneous Complex, southern India: Possible imprint of Late Cretaceous magmatism within rift setting associated with India-Madagascar separation

    NASA Astrophysics Data System (ADS)

    Mohan, M. Ram; Shaji, E.; Satyanarayanan, M.; Santosh, M.; Tsunogae, T.; Yang, Qiong-Yan; Dhanil Dev, S. G.

    2016-05-01

    The gabbro-granophyre-granite complex of Ezhimala emplaced along the western rifted continental margin of India preserves evidence for bimodal magmatism, with related magma mixing and mingling processes. Here we report petrological, geochemical, zircon U-Pb geochronological and Lu-Hf isotopic data from the Ezhimala Igneous Complex (EIC) that provide insights into the Late Cretaceous magmatic activity. Field investigations and petrographic observations in Zircon U-Pb data from the granophyres show emplacement ages of 93.21 ± 0.6 Ma and 94.26 ± 0.92 Ma. The evolved Lu-Hf isotopic systematics for these rocks are indicative of the involvement of older crustal material during magma genesis. The geochemical systematics together with isotopic data suggest magma generation in a rift-related setting, and interaction with or melting of Neoproterozoic basement rocks. The timing of magmatism broadly correlates with the Late Cretaceous Marion hotspot activity which is considered to be responsible for the break-up of India and Madagascar. We thus interpret the EIC to be one of the rare signatures in southern India for the final phase of rifting of Gondwana.

  12. Sources of Mesoproterozoic igneous rocks and formation time of the continental crust of the Kokchetav Massif (Northern Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Tretyakov, A. A.; Kovach, V. P.; Degtyarev, K. E.; Shatagin, K. N.

    2016-12-01

    Within the Kokchetav massif (Northern Kazakhstan), Mesoproterozoic granites and acid volcanics are widespread: these are the youngest Precambrian igneous rocks forming basement of the region. The Nd isotopic characteristics (ɛNd( t)-4.4 ÷-9.6, t Nd(DM) 2.1-2.6 Ga) obtained for these rocks indicate that the source of their melts was the Early Precambrian continental crust. Thus, the continental crust of the Kokchetav Massif had basically been formed by the beginning of the Mesoproterozoic and during the Late Precambrian: later it became a source for the granitoid melts.

  13. Late cretaceous extensional tectonics and associated igneous activity on the northern margin of the Gulf of Mexico Basin

    NASA Technical Reports Server (NTRS)

    Bowen, R. L.; Sundeen, D. A.

    1985-01-01

    Major, dominantly compressional, orogenic episodes (Taconic, Acadian, Alleghenian) affected eastern North America during the Paleozoic. During the Mesozoic, in contrast, this same region was principally affected by epeirogenic and extensional tectonism; one episode of comparatively more intense tectonic activity involving extensive faulting, uplift, sedimentation, intrusion and effusion produced the Newark Series of eposits and fault block phenomena. This event, termed the Palisades Disturbance, took place during the Late Triassic - Earliest Jurassic. The authors document a comparable extensional tectonic-igneous event occurring during the Late Cretaceous (Early Gulfian; Cenomanian-Santonian) along the southern margin of the cratonic platform from Arkansas to Georgia.

  14. A Distinctive Silica-Rich, Sodium-Poor Igneous Clast in the Bovedy (L3) Chondrite

    NASA Astrophysics Data System (ADS)

    Ruzicka, A.; Boynton, W. V.

    1992-07-01

    Description of Bo-1. One slab of the Bovedy (L3) chondrite contains a large (~ 4 x 7 mm) white object that in hand specimen resembles the generally chondritic lithic fragment studied by Rubin et al. (1981). However, SEM, and EMPA studies of this object, designated Bo-1, reveal an unusually Si-rich, Na-poor bulk composition that is manifested by the presence of a silica mineral, the complete absence of olivine, and feldspar that is less sodic than usual for ordinary chondrites. The clast is a highly crystalline igneous rock and exhibits a well-defined crystallization sequence. Orthopyroxene (opx) comprises 83.8 vol% of Bo-1 and is zoned from En(sub)92-85 Wo(sub)0.1-0.2 to En(sub)74 Wo(sub)1.9-2.9. The more magnesian, less calcic opx was the first phase to crystallize in Bo-1. A silica mineral (SiO2, 6.2 vol%), probably either tridymite or cristobalite, crystallized next and appears slightly "corroded" (and veined) by clinopyroxene, suggesting minor reaction between the silica mineral and its surroundings. A small amount (1 vol%) of euhedral-subhedral pigeonite (pig) also crystallized about this time. Plagioclase (plag) was the last phase to join the crystallization sequence and consists of a fine-scale, often lamellar, intergrowth of bytownite-labradorite (5.8 vol%, mainly An(sub)70- 75Or(sub)1-03) and oligoclase (3.1 vol%, mainly An(sub)15-24 Or(sub)13-6). The latter deviates from feldspar stoichiometry and may be partly amorphous. Volumetrically insignificant augite (aug) occurs as (exsolution?) patches within opx, as thin veinlets crossing SiO(sub)2 grains, and as thin rims at the interface of SiO(sub)2 and plag. The rimming and veining aug may have crystallized together with plag from the last liquid in the rock. Minor chromite (0.2 vol%) and trace metal and sulfide are also present. Bulk composition of Bo-1. The composition of the clast was determined by combining SEM modal data with EMPA data for each phase. The calculated composition (in wt%) is: SiO2, 57

  15. Industrial relevance of thermophilic Archaea.

    PubMed

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite in