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Sample records for complexes petrology genesis

  1. Petrology, Geochemistry and Genesis of Ureilites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Hudon, Pierre; Galindo, Charles, Jr.

    2005-01-01

    Ureilites are enigmatic achondrites that have some characteristics resulting from high temperature igneous processing, yet retain other characteristics inherited from the solar nebula. They are basalt-depleted ultramafic rocks containing 7-66 mg/g elemental C. They are rich in noble gases and display a correlation between mg# and Delta (17)O. This mishmash of properties has engendered various models for ureilite genesis, from those in which nebular processes dominate to those in which parent body igneous processes dominate. Characterization of new ureilites, especially of new subtypes, is an important part of attempts to unravel the history of the ureilite parent body or bodies. Here we report on the petrology and geochemistry of a suite of ureilites, mostly from Antarctica, and use these data to discuss ureilite petrogenesis. Additional information is included in the original extended abstract.

  2. Petrologic and In Situ Geochemical Constraints on Diogenite Genesis

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Peng, Z. X.

    2013-01-01

    Diogenites, members of the howardite, eucrite and diogenite (HED) clan, are orthopyroxenite, harzburgite and dunite meteorites [1-3]. Most are breccias, but remnant textures indicate they were originally coarse-grained rocks, with grain sizes of order of cm. Their petrography and compositions support an origin as crustal cumulates from a differentiated asteroid. Astronomical observations, and surface mineralogy and composition of Vesta determined by the Dawn spacecraft suggest that asteroid (4) Vesta is the parent object for HED meteorites [4-6]. The origin of diogenites is an unsettled issue. It is difficult to fit their bulk compositional characteristics into global magma ocean models that successfully describe the compositions of basaltic and cumulate eucrites [7]. Compositional analyses of acid-leached bulk samples have led to the hypothesis that many diogenites were formed late by interaction of their parent melts with a eucritic crust [8]. Those observations may alternatively be explained by subsolidus equilibration of trace elements between orthopyroxene and minor/ accessory phases in the rocks such as plagioclase and phosphate [7]. These competing hypotheses can be tested through in situ measurements of trace and minor elements in orthopyroxene. Our new petrologic observations and in situ minor and trace element data for a suite of diogenites are used to discuss the petrologic evolution of diogenites. Our preliminary data on two diogenites are consistent with the hypothesis that subsolidus element mobilization processes caused unusual trace element signatures seen in some diogenites [7]. We cannot stress strongly enough, however, that the sample set is too small and that additional data are required before definitive conclusions can be made.

  3. The Nabarlek uranium deposit, Northern Territory, Australia: Some petrologic and geochemical constraints on genesis

    SciTech Connect

    Ewers, G.R.; Donnelly, T.M.; Ferguson, J.

    1983-08-01

    The Nabarlek uranium deposit, Northern Territory, Australia, is confined to a shear zone in contorted and metasomatized early Proterozoic schists and occurs near an unconformity with overlying middle Proterozoic sandstone. Massive chlorite + or - sericite + or - hematite rocks, breccias, and intensely altered schists are characteristic of the ore zone, and at least three generations of chlorite have been recognized and described. The primary ore mineral assemblage is dominated by uraninite intergrown with chlorite. The orebody was sericitized at or after 920 m.y. ago, resulting in the widespread replacement and breakdown of chlorite, the formation of hematite, and the solution and redeposition of uraninite. Redox reactions involving iron and uranium are evident in sericitized rocks containing hematite and residual uraninite. High U/Th ratios in the ore zone suggest that uranium was transported to the site of deposition as a uranyl complex. Although no carbonaceous material occurs in the ore zone, isotopic data on minor carbonate associated with uraninite suggest that organic material was originally associated with the mineralization and indicate that these carbonates have evolved from the interaction of hydrothermal fluids with this material. Erosion of the middle Proterozoic cover rocks in the recent past has exposed the deposit to the effects of weathering.

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

    NASA Astrophysics Data System (ADS)

    Gil-Rodriguez, Javier

    2014-12-01

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

  5. Mineralogy and petrology of complex breccia 14063,14

    NASA Technical Reports Server (NTRS)

    Steele, I. M.; Smith, J. V.

    1976-01-01

    Breccia 14063,14 is a complex, probably pre-Imbrian, unmetamorphosed breccia dominated almost entirely by mineral clasts. Electron-probe and microscope examination showed at least four distinct lithologies in a centimeter-sized thin-section. Examination of each lithology showed or suggested the following contributing rock types or mineralogies: (1) dunite with minor chromite, very high-Mg ilmenite and bronzite; (2) spinel troctolite with olivine and Mg-Al spinel; (3) high-Ti mare-like basalt with high-Mg ilmenite and coarse pyroxene; (4) low-KREEP noritic breccia; (5) anorthosite; (6) very Ni-rich Fe metal.

  6. Petrological, geochemical, and stable isotope constraints on the genesis of the Miocene igneous rocks of Chetaibi and Cap de Fer (NE Algeria)

    NASA Astrophysics Data System (ADS)

    Laouar, R.; Boyce, A. J.; Arafa, M.; Ouabadi, A.; Fallick, A. E.

    2005-06-01

    Miocene igneous rocks (diorites, andesites, dacites, rhyolites and microgranites) of Chetaibi and Cap de Fer massif, NE Algeria, are high-K calc-alkaline to shoshonitic rocks. Fresh diorites have δ 34S and δ 18O values ranging between -2.5‰ and +5.9‰, +6.5‰ and +6.7‰ respectively, indicating a mantle origin. The relatively low δ 34S values (-5.4‰ to -12.2‰) and high δ 18O (+8.3‰ to +9.0‰) of altered diorites indicate the input of a crustal component to the initial magma. The microgranites' I-type signature is indicated by the geochemical data and the δ 34S and δ 18O values of -1.2‰ and -3.6‰, and +7.8‰ to +10.4‰ respectively. The andesites show a large variation of δ 34S, between -33.2‰ and +25.7‰. Massive andesites with δ 34S between +6.8‰ and +7.6‰ preserve a 34S-enriched mantle signature. The δ 34S of the lava flows between +25.7‰ and +25.8‰ are attributed to open system magma degassing, whereas the low δ 34S of two andesitic dyke samples (-13.7‰ and -33.2‰) strongly suggest a crustal sulphur input. High δ 18O (+9.2‰ to +15.7‰) of andesites indicate post-magmatic alteration (mainly silicification); the flyschs with δ 18O between of +13.3‰ and +21.7‰ are most likely the contaminant. Quartz veins within the andesites gave a δ 18O value of +23.0‰ while silica-filling vesicles yielded a value of +13.8‰. Initial Sr-isotope data are rather high for all the rocks (diorites: 0.707-0.708, andesites: 0.707-0.710, and microgranites and rhyolites: 0.717-0.719), and because geochemical and stable isotope data do not indicate a substantial amount of crustal assimilation, an extensive enrichment of the mantle source by subducted sediments is called for. A metasomatized-mantle source, characterized by high radiogenic Sr and relatively high δ 18O, has also been indicated for the genesis of similar Tertiary igneous rocks in the Western Mediterranean basin, e.g. the Volcanic Province of southeasten Spain [Benito, R

  7. Petrologic evolution of divergent peralkaline magmas from the Silent Canyon caldera complex, southwestern Nevada volcanic field

    USGS Publications Warehouse

    Sawyer, D.A.; Sargent, K.A.

    1989-01-01

    The Silent Canyon volcanic center consists of a buried Miocene peralkaline caldera complex and outlying peralkaline lava domes. Two widespread ash flow sheets, the Tub Spring and overlying Grouse Canyon members of the Miocene Belted Range Tuff, were erupted from the caldera complex and have volumes of 60-100 km3 and 200 km3, respectively. Eruption of the ash flows was preceded by widespread extrusion of precaldera comendite domes and was followed by extrusion of postcollapse peralkaline lavas and tuffs within and outside the caldera complex. Lava flows and tuffs were also deposited between the two major ash flow sheets. Rocks of the Silent Canyon center vary significantly in silica content and peralkalinity. Weakly peralkaline silicic comendites (PI 1.0-1.1) are the most abundant precaldera lavas. Postcollapse lavas range from trachyte to silicic comendite; some have anomalous light rare earth element (LREE) enrichments. Silent Canyon rocks follow a common petrologic evolution from trachyte to low-silica comendite; above 73% SiO2, compositions of the moderately peralkaline comendites diverge from those of the weakly peralkaline silicic comendites. The development of divergent peralkaline magmas, toward both pantelleritic and weakly peralkaline compositions, is unusual in a single volcanic center. -from Authors

  8. Metasedimentary melting in the formation of charnockite: Petrological and zircon U-Pb-Hf-O isotope evidence from the Darongshan S-type granitic complex in southern China

    NASA Astrophysics Data System (ADS)

    Jiao, Shu-Juan; Li, Xian-Hua; Huang, Hui-Qing; Deng, Xi-Guang

    2015-12-01

    Charnockites are Opx-bearing igneous rocks commonly found in high-grade metamorphic terranes. Despite being volumetrically minor, they show a wide range in both bulk geochemistry and intensive parameters. They form a characteristic component of the AMCG (anorthosite-mangerite-charnockite-granite) suite, but their association with typical S-type granites is less well-known. The Darongshan S-type granitic complex (DSGC) in Guangxi Province, southern China, contains granites varying in mafic silicate mineral assemblages from Bt + Crd (Darongshan suite) to Opx + Grt + Bt + Crd (Jiuzhou suite) and Opx + Crd ± Bt (Taima suite), corresponding to a geochemical transition from magnesian calc-alkalic to ferroan calc-alkalic. However, its genesis, even the accurate age of intrusion, remains highly contentious despite intensive research. In order to understand the genesis of charnockite and its genetic relationship with S-type granite; here, we first determined zircon U-Pb ages of each suite using a SIMS on the basis of a detailed petrological study. Zircon U-Pb ages show that all suites of the complex were emplaced contemporaneously at ca. 249 Ma. Monazite apparent U-Pb ages are indistinguishable from zircon U-Pb ages within analytical error. Further in situ zircon Hf-O isotope analyses reveal that the granitic complex was dominantly derived from reduced melting metasedimentary rocks (δ18Ozircon = ca. 11‰; εHf(t)zircon = ca. - 10; Δlog FMQ ≤ 0; Mn in apatite oxybarometer) with rare material input from the mantle. The variation in δ18O (7.8‰-12.9‰) is more likely a result of hybridization, whereas that in εHf(t) (- 31.9 to - 1.8) is a result of both hybridization and disequilibrium melting. The variation in mineralogy and geochemistry may be interpreted as a result of entrainment of peritectic garnets from biotite-dehydration melting. Nevertheless, heat input from mantle through basaltic intrusion/underplating is considered to play a major role in high

  9. The Dengli (H3.8) Complex Breccia: Petrological and Isotopic Studies

    NASA Astrophysics Data System (ADS)

    Ivanova, M. A.; Assonov, S. S.; Kononkova, N. N.; Shukolyukov, Yu. A.

    1993-07-01

    The Dengli meteorite was found in the Karakum desert in July 1976. Previous studies [1] have shown that the meteorite is a complex chondritic breccia containing unusual components of achondritic affinity. In order to understand the origin of the breccia, we studied its mineralogy, petrology, and isotopic composition of noble gases. In addition, in cooperation with Dr. J. N. Goswami, we are now studying minerals in achondritic clasts using an ion microprobe. The Dengli meteorite has a distinct chondritic texture and consists of chondrules and chondrule fragments embedded into a fine-grained matrix. Equilibrated and unequilibrated populations were found among the chondrules, the latter of which are characterized by normal or inverse Mg-Fe zoning. Olivine (Fa19.6, N = 52, C.V. = 19.3) and pyroxene (Fs18.2, N = 27, C.V. = 17.0) displays large compositional variations. Based on textural and chemical characteristics, Dengli can be classified as an H3.8 chondrite. Two objects with unique compositions were identified. One has a round shape and consists of silica, orthopyroxene (Fs18.1 Wo6.2), clinopyroxene (Fs17.6 Wo27.6), and feldspar (An76.2 Ab23.2). The other object is an angular clast, which is composed of olivine (Fa17.2), Al-rich clinopyroxene (Fs6.3 Wo46.8), and feldspar (An44.7 Ab54.7). The presence of clinopyroxene and Ca-rich feldspar in these objects indicates their similarity with an achondritic material. The Ar, Kr, and Xe contents measured in Dengli are very close to those in other ordinary chondrites of petrological types 3 through 5 [2]. The Xe and Kr isotopic compositions at any temperature step differ from those of solar Xe and Kr. High ^38Ar concentrations were found. The exposure age was estimated to be 7.6 Ma, which is close to the average (6.3 +/- 0.2 Ma) exposure age of 350 H chondrites. The Dengli K/Ar age, 3.73 +/- 0.10 Ga, is close to K/Ar ages of the majority of H chondrites. Thus, Dengli is depleted in noble gases as compared to regolith

  10. The Mount Manengouba, a complex volcano of the Cameroon Line: Volcanic history, petrological and geochemical features

    NASA Astrophysics Data System (ADS)

    Pouclet, André; Kagou Dongmo, Armand; Bardintzeff, Jacques-Marie; Wandji, Pierre; Chakam Tagheu, Pulchérie; Nkouathio, David; Bellon, Hervé; Ruffet, Gilles

    2014-09-01

    The volcanic story of Mount Manengouba is related to four chronological stages: (1) forming of the early Manengouba shield volcano between 1.55 and 0.94 Ma, (2) building of the Eboga strato-cone between 0.94 and 0.89 Ma, (3) caldera collapse and silicic extrusions of the Elengoum Complex between 0.89 and 0.70 Ma, and (4) intra-caldera and flank activity between 0.45 and 0.11 Ma. The volume of the volcano is calculated at 320 km3 ± 5%. The volcanic rocks are attributed to two magmatic outputs. The first and main magma generation produced the shield volcano, the strato-cone, and the syn- to post-caldera extrusions, displaying a complete series from basanites to trachytes (magmatic Group 1). The second magma generation is limited to the late and flank activity evolving from basanites to trachy-phonolite (magmatic Group 2). Both magmatic groups belong to the under-saturated alkaline sodic series. Petrological calculations locate the magmatic reservoir between 37 and 39 km in the upper mantle for the Group 1 lavas, and between 42 and 44 km for the Group 2 lavas. Trachytes were generated in a secondary crustal reservoir. Magmatic series evolve with medium to low pressure fractional crystallization of olivine, pyroxene, oxides, feldspar, and apatite. Significant crustal assimilation is evidenced in trachytes. The magma of Group 1 was generated with 3-6% of partial melting of a moderately enriched source containing 3-7% of garnet. Melting took place in the spinel to garnet transition zone located at 70-90 km and around 25 kb. The magma of Group 2 resulted from a slightly higher partial melting from a less garnet-rich source that indicates uprising of the melting column in the upper part of transition zone. Sr, Nd, and Pb isotope data of the Manengouba rocks and neighboring lavas are analyzed and compared with those of the mafic lavas of the CVL. Three source components are distinguished: a depleted component originated from the asthenospheric swell, a radiogenic component

  11. Petrological and geochemical constraints on the origin of adakites in the Garibaldi Volcanic Complex, southwestern British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Fillmore, Julie; Coulson, Ian M.

    2013-07-01

    The Garibaldi Volcanic Complex (GVC) is located in southwestern British Columbia and comprises two related but distinct volcanic fields: the Garibaldi Lake and the Mount Garibaldi volcanic fields. The rocks of the GVC range from basalt to rhyolite, and analyses of samples from both fields distinguish these as adakites. The GVC magmas have high Sr/Y, Mg#, and Al2O3; low K2O/Na2O; and fractionated rare earth element compositions. Models of adakite genesis fall into two main groups: slab melting and non-slab melting. Adakites generated by slab melting commonly occur from young subducting crust (≤25 Ma) and are felsic partial melts of the subducting slab that interact with the mantle wedge during ascent. Non-slab melting models vary widely and include basalt fractionation, assimilation, fractional crystallization processes and partial melting of mafic lower crust. Data from the GVC are too limited to fully elucidate the mechanisms of adakite genesis; however, the petrographical and geochemical characteristics of the GVC rocks in this study do not refute an origin by slab partial melts. Variations in trace elements that reflect non-adakitic values (e.g., low La, low Cr) are likely the result of magma mixing at shallow depths within the magma reservoirs of each center, for which there is mineralogical and textural evidence. The adakite rocks of the GVC share geochemical traits akin to both low-SiO2 adakite (LSA) and high-SiO2 adakite (HSA) groups, though additional data are needed to investigate whether LSA- or HSA-type dominates within the GVC, and by extension, which should be the preferred model of adakite genesis.

  12. UNIT, PETROLOGY.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THIS TEACHER'S GUIDE FOR A UNIT ON PETROLOGY IS SUITABLE FOR ADAPTATION AT EITHER THE UPPER ELEMENTARY OR THE JUNIOR HIGH SCHOOL LEVELS. THE UNIT BEGINS WITH A STORY THAT INTRODUCES VOLCANIC ACTION AND IGNEOUS ROCK FORMATION. SELECTED CONCEPTS ARE LISTED FOLLOWED BY SUGGESTED ACTIVITIES. A BIBLIOGRAPHY, FILM LIST, VOCABULARY LIST, AND QUESTION AND…

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

    NASA Astrophysics Data System (ADS)

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

    1981-04-01

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

  14. Petrology, geochemistry and geochonology of the Jacupiranga ultramafic, alkaline and carbonatitic complex (southern Brazil)

    NASA Astrophysics Data System (ADS)

    Chmyz, Luanna; Arnaud, Nicolas; Biondi, João Carlos

    2015-04-01

    Brazilian carbonatitic complexes are located at the edges of the Paleozoic basins and are usually associated to tectonic crustal flexuring or deep fault zones. The Jacupiranga Complex is a 65 km² ultrabasic-alkaline carbonatitic intrusive body outcroping at the northeastern border of the Paraná Basin, South of São Paulo State (Brazil). The northern portion of the unit is mostly composed of peridotitic rocks, while the southern part contains ijolites, melteigites, clinopyroxenites and carbonatites which host a phosphate deposit, mined since 1966. Even though the carbonatites only represent 1% of the Complex's area, they have concentrated most of the historical petrogenetic studies, leaving almost unknown the petrogenetic and the geochronological characteristics of other rocks. This explains why the few petrogenetic models from the literature are very partial and mostly unsatisfactory. While the peridotitic rocks are largely hindered by the absence of fresh outcrops, the regolith thickness and the high serpentinization degree, field observations and petrographic data notably show a heterogeneous zone around the peridotitic body. That zone is composed of a large variety of lithotypes over a relatively small area (~9 km²), comprising diorites, monzodiorites, alkali feldspar syenites, trachytes, lamprophyres and syenites. Moreover, these rocks present a restricted lateral continuity (decametric) and a lack of the magmatic bedding characteristic of the ijolitic and clinopyroxenitc rocks. The southern clinopyroxenitic zone (~20 km²) is composed of clinopyroxenite and melteigite with prominent magmatic layering, probably of cumulative origin, and a body of carbonatites which outcrops over less than 1 km2 essentially composed of sovite and beforsite, with abundant apatite. The Jacupiranga Complex characteristics indicate that its formation possibly comprises at least five magmatic events which cannot at present be surely ordinated in time: a) the emplacement of the

  15. Petrology of the freetown layered complex, Sierra Leone: part II. Magma evolution and crystallisation conditions

    NASA Astrophysics Data System (ADS)

    Chalokwu, C. I.

    2001-04-01

    The Freetown Layered Complex, Sierra Leone, is a 65 km long, 14 km wide and 7 km thick tholeiitic intrusion, which had been intruded in the West African Craton during the Jurassic (˜ 190 Ma) opening of the middle Atlantic Ocean. The complex consists of four zones of rhythmically layered sequences of Pl+Ol+Aug±Tmt-Ol+Opx+Pgt+Ol-Pgt. Cumulus inverted pigeonite first appeared at the bottom of Zone 2 before disappearing in the middle of Zone 3 only to reappear at the top of Zone 4 with cumulus titanomagnetite. Calculated emplacement pressures, based on the compositions of coexisting plagioclase-pyroxene and the CaTs reaction, range from 2.8 to 5.1 kbar. Two-pyroxene geothermometer gives crystallisation temperatures of 972-1305 ± 70°C, which compare favourably with temperatures estimated from O isotope thermometers (1040-1290 ± 60°C) and plagioclase-liquid thermometers (1045-1381°C) applied to the Freetown bulk composition and obtained by geochemical summation for each zone. Fe-Ti oxides have all re-equilibrated during subsolidus cooling of the complex, but yield fO 2 between quartz-fayalite-magnetite and wüstite-magnetite buffers at high pressure. Silica activity, based on the En = Fo + SiO 2 equilibrium, has been calculated for the entire stratigraphic section. Instead of a progressive increase from the bottom to the top of the complex, values of silica activity fluctuate within the zones, with major decreases corresponding to levels of new magma additions or the arrival of cumulus titanomagnetite. Stratigraphic summation of whole rock chemical composition of cumulates for zones 2-4, weighted according to the average density of the zones, indicates the zones were produced by multiple injection of high alumina (18.38-20.47 wt%) low Ti (0.46-0.70 wt%) hypersthene-normative tholeiites with moderately high activities of silica. Numerical simulation using the COMAGMAT computer algorithm indicates zone 4 bulk composition, interpreted as approximating the parental

  16. Petrology, geochemistry, and geochronology of trondhjemites from the Qori Complex, Neyriz, Iran

    NASA Astrophysics Data System (ADS)

    Fazlnia, Abdolnaser; Schenk, Volker; van der Straaten, François; Mirmohammadi, Mirsaleh

    2009-10-01

    Metamorphism, magmatism, and thrusting were the result of subduction of Neotethys beneath the continental-margin arc of the Sanandaj-Sirjan shear zone (SSSZ) during the Mesozoic. The Qori metamorphic complex is a part of the southern SSSZ. Leuco-granitic (trondhjemitic) rocks crop out in the Qori metamorphic complex and are rare rock types in the SSSZ. These rocks have intruded into the marbles and garnet amphibolites, the highest grade metamorphic rocks of the Qori metamorphic complex, and in some outcrops, a transitional boundary between the amphibolites and the granitoids can be distinguished. The granitoids are granular in texture and consist of plagioclase (albite-oligoclase), quartz ± K-feldspar ±muscovite and subordinate garnet, spinel, rutile, and apatite which primarily occur as inclusions in the main phases. The peraluminous trondhjemitic rocks are enriched in Na 2O and SiO 2 and depleted in FeO, MgO, and CaO. Similarities with some trondhjemitic liquids produced through partial melting of amphibolites or hydrous basalts (i.e., low-Al 2O 3 content, less than 15 wt.%; low Ba, Sr, TiO 2, and Eu content, all with negative anomalies; moderately enriched LREEs and Y, and flat HREE patterns) suggest that the evolution of the parental magma was controlled by residual plagioclases during partial melting of a garnet amphibolite source. Concentrations of ferromagnesian elements, Mg, Fe, and Mn, are low, suggesting that the granitic rocks were not produced by high degrees of partial melting. Furthermore, they display low amounts of ferromagnesian components from the protolith (garnet amphibolite). This is supported by consideration of compatible elements, especially Cr, Ni and Ti (and the less robust HREE), which respectively show very high and high bulk partition coefficients for relatively small degrees (< 20%) of partial melting of the source. The partial melting of the garnet amphibolites occurred at pressures and temperatures between 7.5 and 9.5 kbar (at a

  17. Petrogenesis of the Sabongari alkaline complex, cameroon line (central Africa): Preliminary petrological and geochemical constraints

    NASA Astrophysics Data System (ADS)

    Njonfang, Emmanuel; Tchoneng, Gilbert Tchuenté; Cozzupoli, Domenico; Lucci, Federico

    2013-07-01

    The petrography, mineral chemistry and geochemical features of the Sabongari alkaline complex are presented and discussed in this paper with the aim of constraining its petrogenesis and comparing it with other alkaline complexes of the Cameroon Line. The complex is mainly made up of felsic rocks: (i) granites predominate and include pyroxene-amphibole (the most abundant), amphibole-biotite, biotite and pyroxene types; (ii) syenites are subordinate and comprise amphibole-pyroxene and amphibole-biotite quartz syenites; (iii) pyroxene-amphibole-biotite trachyte and (iv) relatively abundant rhyolite. The minor basic and intermediate terms associated with felsic rocks consist of basanites, microdiorite and monzodioites. Two groups of pyroxene bearing rocks are distinguished: a basanite-trachyte-granite (Group 1) bimodal series (SiO2 gap: 44 and 63 wt.%) and a basanite-microdiorite-monzodiorite-syenite-granite (Group 2) less pronounced bimodal series (reduced SiO2 gap: 56-67 wt.%). Both are metaluminous to peralkaline whereas felsic rocks bare of pyroxene (Group 3) are metaluminous to peraluminous. The Group 1 basanite is SiO2-undersaturated (modal analcite in the groundmass and 11.04 wt.% normative nepheline); its Ni (240 ppm) and Cr (450 ppm) contents, near mantle values, indicate its most primitive character. The Group 2 basanite is rather slightly SiO2-saturated (1.56 wt.% normative hypersthene), a marker of its high crustal contamination (low Nb/Y-high Rb/Y). The La/Yb and Gd/Yb values of both basanites (1: 19.47 and 2.92; 2: 9.09 and 2.23) suggest their common parental magma composition, and their crystallization through two episodes of partial melting (2% and 3% respectively) of a lherzolite mantle source with <4% residual garnet. The effects of crustal contamination were selectively felt in the values of HFSE/LREE, LREE/LILE and LREE/HFSE ratios, known as indicators. Similar features have been recently obtained in the felsic lavas of the Cameroon Volcanic Line.

  18. Petrological and geochemical constraints on granitoid formation: The Waldoboro Pluton Complex, Maine

    SciTech Connect

    Barton, M. . Dept. of Geological Science); Sidle, W.S. )

    1992-01-01

    The Waldoboro Pluton Complex (WPC) comprises seven units ranging from qtz-diorite to aplite. The country rocks are biotite-rich metagraywackes with minor shales mostly belonging to the Proterozoic Z-Ordovician Bucksport Formation. Field evidence strongly suggests that the WPC formed in-situ: contacts with the country rock are cryptic, transitional and concordant; restitic minerals in the granitoids are identical to those in the country rocks; prolific metasedimentary enclaves in the WPC are locally derived. Major and trace element data for country rock and the most voluminous units of the WPC define consistent linear trends suggesting limited melt segregation and retention of a high proportion of restite. Mixing models and partial melting models require 54--76% melting for generation of the gneissic granites and two-mica granites. Garnet-biotite geothermometry and garnet-Al[sub 2]SiO[sub 5]-SiO[sub 2]-plagioclase geobarometry indicate that the WPC formed at T = 740--780 C and P = 0.4--0.7 GPa. Published experimental data show that < 50% melting is likely under these conditions if melting is controlled by dehydration reactions. Bucksport lithologies contain < 20% biotite, suggesting that the maximum amount of melt that could have formed by dehydration melting is < 20%, even if all biotite was consumed during melting. It seems probable that a free fluid phase was required to generate the WPC. Migmatization is apparent in all lithologies (including amphibolites) in the vicinity of the WPC, consistent with fluid-present melting. Fluid may have ingressed along the St. George thrust, but the source of the fluid is unknown.

  19. A petrological and geochemical study of the Surna Nappe (Seve Nappe Complex?) in the Central Scandinavian Caledonides, Norway

    NASA Astrophysics Data System (ADS)

    Weigand, Silvia; Hauzenberger, Christoph; Gasser, Deta

    2016-04-01

    The Seve Nappe Complex, mainly outcropping and investigated in Sweden, comprises relics of Ordovician HP and UHP metamorphic rocks, which were overprinted by upper amphibolite facies metamorphism and anataxis during the Silurian. In Norway, in the hinterland of the Caledonian orogen, rocks of the Surna and Blåhø nappes are generally correlated with the Seve Nappe Complex. However, no detailed metamorphic studies are available from these units to compare it with the Seve Nappe Complex. The Surna and Blåhø nappes are located between the oceanic-derived Støren nappe and the continentally-derived Sætra nappe. Due to a strong post-Caledonian extensional and transtensional overprint and a close proximity to the MTFC (Møre-Trøndelag Fault Complex, a prominent post-Caledonian strike-slip fault complex) investigations of the early metamorphic history of the Surna and Blåhø nappes are challenging. In this contribution we present the results of a petrological and geochemical study of the Surna Nappe, from a ca. 10 km wide transect across this nappe west of Trondheim in Norway. The nappe is lithologically very heterogenous, consisting of quartz-rich mica-schists, amphibole-garnet-mica-schists, amphibolites, calcsilicates as well as pegmatites. Geochemically, the whole rock compositions vary from ultrabasic to acidic, but a distinction between metavolcanic and metasedimentary origin of the lithologies is not always straightforward. Although there are metabasic rocks present they do not show a mineral assemblage with a relic eclogite facies. Garnet occurs in several lithologies and is used together with plagioclase and biotite for conventional geothermobarometry using the TWQ and PET software tools. Additionally, Zr-in-rutile and garnet-biotite thermometers were applied. PT calculations from 18 different samples reveal PT conditions of 600 to 700°C and pressures of 10 to 16 kbar. The elevated phengite content in muscovite (Si up to 3.28) in a few samples may indicate

  20. Petrology, geochemistry and geochronology of the magmatic suite from the Jianzha Complex, central China: Petrogenesis and geodynamic implications

    NASA Astrophysics Data System (ADS)

    Li, Xiaowei; Mo, Xuanxue; Bader, Thomas; Scheltens, Mark; Yu, Xuehui; Dong, Guochen; Huang, Xiongfei

    2014-12-01

    The intermediate-mafic-ultramafic rocks in the Jianzha Complex (JZC) at the northern margin of the West Qinling Orogenic Belt have been interpreted to be a part of an ophiolite suite. In this study, we present new geochronological, petrological, geochemical and Sr-Nd-Hf isotopic data and provide a different interpretation. The JZC is composed of dunite, wehrlite, olivine clinopyroxenite, olivine gabbro, gabbro, and pyroxene diorite. The suite shows characteristics of Alaskan-type complexes, including (1) the low CaO concentrations in olivine; (2) evidence of crystal accumulation; (3) high calcic composition of clinopyroxene; and (4) negative correlation between FeOtot and Cr2O3 of spinels. Hornblende and phlogopite are ubiquitous in the wehrlites, but minor orthopyroxene is also present. Hornblende and biotite are abundant late crystallized phases in the gabbros and diorites. The two pyroxene-bearing diorite samples from JZC yield zircon U-Pb ages of 245.7 ± 1.3 Ma and 241.8 ± 1.3 Ma. The mafic and ultramafic rocks display slightly enriched LREE patterns. The wehrlites display moderate to weak negative Eu anomalies (0.74-0.94), whereas the olivine gabbros and gabbros have pronounced positive Eu anomalies. Diorites show slight LREE enrichment, with (La/Yb)N ratios ranging from 4.42 to 7.79, and moderate to weak negative Eu anomalies (Eu/Eu∗ = 0.64-0.86). The mafic and ultramafic rocks from this suite are characterized by negative Nb-Ta-Zr anomalies as well as positive Pb anomalies. Diorites show pronounced negative Ba, Nb-Ta and Ti spikes, and typical Th-U, K and Pb peaks. Combined with petrographic observations and chemical variations, we suggest that the magmatism was dominantly controlled by fractional crystallization and crystal accumulation, with limited crustal contamination. The arc-affinity signature and weekly negative to moderately positive εNd(t) values (-2.3 to 1.2) suggest that these rocks may have been generated by partial melting of the juvenile

  1. Transient Spectroscopic Characterization of the Genesis of a Ruthenium Complex Catalyst Supported on Zeolite Y

    SciTech Connect

    Ogino, Isao; Gates, Bruce C.

    2010-01-12

    A mononuclear ruthenium complex anchored to dealuminated zeolite HY, Ru(acac)(C{sub 2}H{sub 4}){sup 2+} (acac = acetylacetonate, C{sub 5}H{sub 7}O{sup 2}{sup -}), was characterized in flow reactors by transient infrared (IR) spectroscopy and Ru K edge X-ray absorption spectroscopy. The combined results show how the supported complex was converted into a form that catalyzes ethene conversion to butene. The formation of these species resulted from the removal of acac ligands from the ruthenium (as shown by IR and extended X-ray absorption fine structure (EXAFS) spectra) and the simultaneous decrease in the symmetry of the ruthenium complex, with the ruthenium remaining mononuclear and its oxidation state remaining essentially unchanged (as shown by EXAFS and X-ray absorption near-edge structure spectra). The removal of anionic acac ligands from the ruthenium was evidently compensated by the bonding of other anionic ligands, such as hydride from H2 in the feed stream, to form species suggested to be Ru(H)(C{sub 2}H{sub 4}){sub 2}{sup +}, which is coordinatively unsaturated and inferred to react with ethene, leading to the observed formation of butene in a catalytic process.

  2. Petrology of the Motaghairat mafic-ultramafic complex, Eastern Desert, Egypt: A high-Mg post-collisional extension-related layered intrusion

    NASA Astrophysics Data System (ADS)

    Abdel Halim, Ali H.; Helmy, Hassan M.; Abd El-Rahman, Yasser M.; Shibata, Tomoyuki; El Mahallawi, Mahmoud M.; Yoshikawa, Masako; Arai, Shoji

    2016-02-01

    The geodynamic settings of the Precambrian mafic-ultramafic complexes in the Eastern Desert of Egypt have important bearing on understanding the geotectonic evolution of the Arabian Nubian Shield. We present a detailed petrological study on a layered mafic-ultramafic intrusion that is located at the contact between the Precambrian continental crust and the Miocene Red Sea oceanic crust. The Motaghairat layered intrusion consists of basal lherzolite, orthopyroxenite, troctolite, olivine gabbro and anorthosite on the top. Variations in modal mineralogy and mineral chemistry along with the chemical composition of these units suggest their derivation from a common high-Mg tholeiitic parent melt through fractional crystallization processes. The parental magma was derived from a metasomatised mantle source. The primitive mantle-normalized patterns of the calculated melts exhibit enrichment in U relative to Th and Ba relative LREE which indicate that the enriched lithospheric mantle source was metasomatised by fluids derived from a subducted oceanic crust rather than by a sediment melt. Geological and petrological evidences suggest that the layered Motaghairat intrusion was emplaced during post-orogenic extension following subduction break-off and lithospheric delamination after the collision between the amalgamated island arc terranes and the Saharan Metacraton. The heat source required to melt the metasomatised lithospheric mantle was derived from the upwelling of hot asthenosphere after the subduction-break-off.

  3. Foliated breccias in the active Portuguese Bend landslide complex, California: bearing on melange genesis

    SciTech Connect

    Larue, D.K.; Hudleston, P.J.

    1987-05-01

    The active portion of the Portuguese Bend landslide complex is approximately 3 km/sup 2/ in area and 30-50 m thick. Measured displacement rates range from less than one to greater than 30 mm/day on different parts of the landslide, with total displacements over the last 30 yrs ranging from about 10 to greater than 150 m. Six types of breccia, each locally with a foliated matrix, were recognized in the active landslide complex and are absent outside the landslide complex. Slide-body breccias are of two types, the first formed by extensional fracturing during bulk pure shear at the top of the landslide (slide-top breccia) and the second by flow of tuffaceous shales and fracture of embedded siliceous shales during simple shear deep in the landslide to the basal decollement (slide-bottom breccias). Slide-margin breccias, also in simple shear, are produced on the lateral margins of individual slide blocks accompanying wrench-fault motion. Other breccias (fault-ramp breccias) are formed during motion over ramps. Colluvial deposits within tension gashes (crack-fill breccias) and at the toe of the slide (slide-toe breccias) represent a fifth breccia type. Diapirs originating from over-pressured zones at the slide base also contain breccia. Recognition of different breccia types in ancient rocks would be difficult, because fabrics in the different types are similar. Foliations are defined by: scaly cleavage, compositional banding and color banding (in shear zones), stretched mud clasts, and aligned hard grains. Foliated breccias are synonymous with melanges. The authors regard the six breccia types described herein as representing the principal types of melange that occur in ancient accretionary settings.

  4. [IMPACT OF RONCOLEUKIN ON BALANCE OF CYTOKINS IN COMPLEX TREATMENT OF OBTURATION JAUNDICE OF NONTUMORAL GENESIS].

    PubMed

    Gajiyev, J N; Tagiyev, E G; Gadjiyev, N J

    2016-02-01

    The results of surgical treatment of 137 patients, suffering obturation jaundice of non-tumoral etiology, were analyzed. In all the patients the cause of obturation jaundice was choledocholithiasis. Roncoleukin was infused intravenously additionally in a complex of therapy. A degree of hepatic dysfunction was determined, taking into account the cholestasis markers. In 23 patients purulent cholangitis have occurred on background of obturation jaundice. Concentration of cytokins TNF-α, IFN-γ, IL-1, IL-2, IL-4, IL-6, IL-10 in sera were determined, using immunoassay analysis. The cytokins dysbalance severity preoperatively and dynamics of its changes have depended upon the hepatic dysbalance degree and presence of purulent cholangitis; a dysbalance is deeper, when the hepatic dysfunction is higher. Application of pathogenetically substantiated purposeful cytokinotherapy, including roncoleukin, have promoted the cytokins dysbalance elimination and improvement of the patients treatment results. PMID:27244913

  5. A Mantle Genesis for Andesitic Melts of the Shisheisky Complex, Kamchatka

    NASA Astrophysics Data System (ADS)

    Yogodzinsk, G.; Bryant, J.; Churikova, T.

    2008-12-01

    Primitive andesites from the Shisheisky Complex, a field of Quaternary-age, monogenetic cones located in the Aleutian-Kamchatka junction, north of Shiveluch Volcano (Portnyagin et al., 2007 Geoph. Monograph 172), are similar to primitive andesites from Mt. Shasta, Piip Volcano, and Setouchi, Japan. They have Mg numbers of 0.66-0.73 at intermediate SiO2 (54-58 wt%), low CaO/Al2O3 (<0.54), and high Ni (184-243 ppm) and Cr (418-880 ppm). Olivine phenocryst core compositions of Fo90 appear to be in equilibrium with whole-rock "melts", consistent with the aphyric to sparsely phyric nature of the lavas. Compared to the Shisheisky andesites, primitive basalts from the region (Alaid, Tolbachik, Kharchinsky) have higher CaO/Al2O3 (0.69-0.86) and lower whole-rock Ni/MgO (10-17) at similar Mg numbers (0.66-.70). Olivine phenocrysts in the basalts have high CaO, low Ni, and low Ni/MgO at Fo88 compared to the andesites. The absence of plagioclase phenocrysts from the primitive andesites strongly contrasts petrographic observations of the plagioclase-phyric basalts, indicating relatively high pre-eruptive water contents for the andesites compared to the basalts. Estimated temperature and water contents range from 984° - 1143° C and 4-7 wt% H2O for andesites and 1149° -1227° C and 2 wt% H2O for basalts. Petrographic and mineral composition data suggest that the primitive andesites were liquids in equilibrium with mantle peridotite, and were not produced by mixing between basalts and rhyolites, contamination of xenocrystic olivine, or crystal fractionation of basalt. Instead, the key features of the Shisheisky primitive andesites appear to have been acquired by interactions between eclogite melts of the torn Pacific plate edge and mantle peridotite. Mixing between these reacted melts and primitive basalts at sub-moho depths produces the range of compositions observed in the Shisheisky lavas.

  6. Geophysical and petrological modelling of the structure and composition of the crust and upper mantle in complex geodynamic settings: The Tyrrhenian Sea and surroundings

    NASA Astrophysics Data System (ADS)

    Panza, G. F.; Peccerillo, A.; Aoudia, A.; Farina, B.

    2007-01-01

    Information on the physical and chemical properties of the lithosphere-asthenosphere system (LAS) can be obtained by geophysical investigation and by studies of petrology-geochemistry of magmatic rocks and entrained xenoliths. Integration of petrological and geophysical studies is particularly useful in geodynamically complex areas characterised by abundant and compositionally variable young magmatism, such as in the Tyrrhenian Sea and surroundings. A thin crust, less than 10 km, overlying a soft mantle (where partial melting can reach about 10%) is observed for Magnaghi, Vavilov and Marsili, which belong to the Central Tyrrhenian Sea backarc volcanism where subalkaline rocks dominate. Similar characteristics are seen for the uppermost crust of Ischia. A crust about 20 km thick is observed for the majority of the continental volcanoes, including Amiata-Vulsini, Roccamonfina, Phlegraean Fields-Vesuvius, Vulture, Stromboli, Vulcano-Lipari, Etna and Ustica. A thicker crust is present at Albani - about 25 km - and at Cimino-Vico-Sabatini — about 30 km. The structure of the upper mantle, in contrast, shows striking differences among various volcanic provinces. Volcanoes of the Roman region (Vulsini-Sabatini-Alban Hills) sit over an upper mantle characterised by Vs mostly ranging from about 4.2 to 4.4 km/s. At the Alban Hills, however, slightly lower Vs values of about 4.1 km/s are detected between 60 and 120 km of depth. This parallels the similar and rather homogeneous compositional features of the Roman volcanoes, whereas the lower Vs values detected at the Alban Hills may reflect the occurrence of small amounts of melts within the mantle, in agreement with the younger age of this volcano. The axial zone of the Apennines, where ultrapotassic kamafugitic volcanoes are present, has a mantle structure with high-velocity lid ( Vs ˜ 4.5 km/s) occurring at the base of a 40-km-thick crust. Beneath the Campanian volcanoes of Vesuvius and Phlegraean Fields, the mantle

  7. Influence of contrasting aspect, lithology, and vegetation on saprolite genesis in complex terrain: Reynolds Creek Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Klos, P. Z.; Link, T. E.; Durrett, W.; Heinse, R.; Seyfried, M. S.; Leonard, E. M.

    2014-12-01

    This study employs a variety of geophysical, biological, hydrological, and pedological methods to expand on the understanding of how contrasting aspects, lithologies, and vegetation influence critical zone structure and evolution. We performed shallow seismic refraction (SSR) and time-lapse electrical resistivity tomography (ERT) surveys across two geologically distinct valleys within the Reynolds Creek Critical Zone Observatory in southwestern Idaho. We also quantified vegetation density, soil pH, and subsurface stratigraphy (by manual sampling) across opposing north-facing (forested) and south-facing (unforested) aspects to better understand the relationship between lithology, vegetation, seasonal moisture dynamics, and saprolite genesis within the critical zone. The first study sub-site, Upper Johnston Draw, resides on late Cretaceous granitic bedrock associated with the Idaho Batholith. The second study sub-site, Upper Sheep Creek, resides on Miocene basaltic bedrock. In the granitic Upper Johnston Draw there is a sharp contrast in depth to unweathered bedrock (regolith thickness) between the north-facing aspect (average depth of 18.6 m) and the south-facing aspect (average depth of 8.2 m). In the basaltic Upper Sheep Creek there is only a marginal contrast in depth to unweathered bedrock between the north-facing aspect (average depth of 14.4 m) and the south-facing aspect (average depth of 12.0 m). These observed relationships between the contrasting lithologies of Upper Johnston Draw and Upper Sheep Creek, coupled with our time-lapse ERT surveys, vegetation density tests, soil pH tests, and subsurface augering data, provide new understanding about the causes of symmetry or asymmetry in saprolite development on north-facing and south-facing slopes. Specifically, these findings suggest that abiotic chemical weathering via hydrolysis may be the dominant control creating the symmetrical pattern of saprolite genesis (north vs. south aspects) observed within the

  8. Assessment of Petrological Microscopes.

    ERIC Educational Resources Information Center

    Mathison, Charter Innes

    1990-01-01

    Presented is a set of procedures designed to check the design, ergonomics, illumination, function, optics, accessory equipment, and image quality of a microscope being considered for purchase. Functions for use in a petrology or mineralogy laboratory are stressed. (CW)

  9. The Beginnings of Experimental Petrology

    ERIC Educational Resources Information Center

    Eugster, Hans P.

    1971-01-01

    An account of Van't Hoff's change from theoretical chemistry to petrology provides data on the European intellectual climate of the early 1900's and shows how his work laid the foundation for experimental petrology of hard rocks." (AL)

  10. Petrology and Geochemistry of New Ureilites and Ureilite Genesis

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Herrin, J. S.; Downes, H.

    2007-01-01

    Ureilites are C-bearing, basalt-depleted olivine+pyroxene achondrites from a differentiated asteroid. The group is heterogeneous, exhibiting ranges in O isotopic composition, Fe/Mg, Fe/Mn, pyx/ol, siderophile and lithophile trace element content, and C content and isotopic composition [1]. Some of these characteristics are nebular in origin; others were strongly overprinted by asteroidal igneous processes. The consensus view is that most ureilites are melt-residues, but some are partial cumulates or have interacted with a melt [1,2]. An "unroofing" event occurred while the parent asteroid was hot that froze in mineral core com-positions and resulted in FeO reduction at olivine grain margins. We have studied several new ureilites, but will focus here on two anomalous stones; LAR 04315 and NWA 1241. LAR 04315 is texturally unusual. It contains olivine with angular subdomains, and low-Ca pyroxene riddled with wormy inclusions of metal+troilite, graphite, and possibly other phases, and irregular inclusions of high-Ca pyroxene. Reduction occurred along olivine grain margins and internal fractures, but not along subdomain boundaries. Although texturally odd, LAR 04351 is a typical ureilite in mineral and bulk composition. The olivine is Fo80.8 and falls on the ureilite Fe/Mn-Fe/Mg trend. Its olivine composition falls within the range of the majority of ureilites, and it is typical of these ureilites in bulk rock lithophile and siderophile element contents.

  11. Stratigraphy, petrology, and geochemistry of the Spurr Volcanic Complex, eastern Aleutian Arc, Alaska. [(Appendix for geothermal fluid chemistry)

    SciTech Connect

    Nye, C.J.

    1987-12-01

    The Spurr Volcanic Complex (SVC) is a calcalkaline, medium-K, sequence of andesites erupted over the last quarter of a million years by the easternmost currently active volcanic center in the Aleutian Arc. The ancestral Mt. Spurr was built mostly of andesites of uniform composition (58 to 60% SiO/sub 2/), although andesite production was episodically interrupted by the introduction of new batches of more mafic magma. Near the end of the Pleistocene the ancestral Mt. Spurr underwent Bezyianny-type avalanche caldera formation, resulting in the production of a volcanic debris avalanche with overlying ashflows. Immediately afterward, a large dome (the present Mt. Spurr) was emplaced in the caldera. Both the ashflows and dome are made of acid andesite more silicic than any analyzed lavas from the ancestral Mt. Spurr (60 to 63% SiO/sub 2/), yet contain olivine and amphibole xenocrysts derived from more mafic magma. The mafic magma (53 to 57% SiO/sub 2/) erupted during and after dome emplacement, forming proto-Crater Peak and Crater Peak. Hybrid pyroclastic flows and lavas were also produced. Proto-Crater Peak underwent glacial dissection prior to the formation of Crater Peak in approximately the same location. Appendices II through VIII contain a summary of mineral compositions; Appendix I contains geochemical data. Appendix IX by R.J. Motyka and C.J. Nye describes the chemistry of geothermal fluids. 78 refs., 16 figs., 3 tabs.

  12. Plutonic ultramafic-mafic complexes of the Vel'may terrane, eastern Chukotka (Russia): first petrological results and preliminary geodynamic interpretations

    NASA Astrophysics Data System (ADS)

    Ledneva, G. V.; Bazylev, B. A.; Kuzmin, D.; Ishiwatari, A.; Kononkova, N. N.; Sokolov, S. D.

    2012-04-01

    The Vel'may terrane (eastern Chukotka) is commonly considered as a continuity of the South Anyui Suture (SAS) zone (western Chukotka) and the Angaucham terrane (Brooks Range, Alaska), which marks the southern boundary of the Arctic Alaska - Chukotka displaced continental microplate (AACM). The correlation of terranes bounding the microplate is based on findings of similar upper Triassic (Norian) faunas (Tynankergav, Bychkov, 1987; Sokolov et al., 2009) and the ubiquitous occurrence of ultramafic-mafic plutonic complexes attributed to be ophiolite fragments. However, plutonic complexes of the Vel'may terrane haven't been petrologically investigated till now. In the study area they spatially associate with upper Jurassic-lower Cretaceous deposits of the Cross Bay zone and upper Triassic sequences of the Kolyuchinskaya Bay zone. In the Cross Bay zone ultramafic and mafic rocks compose small tectonic slices and are represented by non-spreading subduction-related restite spinel harzburgites and shallow-level plagioclase peridotite and gabbro cumulates (crystallization pressure is estimated at 3.5±1 and 1.5±1 kb ((Schmidt, 1992), respectively) closely resembling fragments of an ophiolitic assemblage. In the Kolyuchinskaya Bay zone tectonic slices of ultramafic and mafic rocks are dominated by clinopyroxene-bearing dunites, hornblende wehrlites/olivine clinopyroxenites and hornblende gabbros. This rocks are high-pressure cumulates (crystallization pressure is estimated at 8±1 kb (Schmidt, 1992)) of lower crustal magma-chambers originated in a mature island-arc or an Andean-type active continental margins. Remnants of subduction-related ophiolite and magma-chambers are typical of sutures indicative of an arc-continent collision; and they occur widely in the SAS zone (Lychagin, 1985; Ganelin, Sylantyev, 2008) and the Angayucham terrane (Loney, Himmelberg, 1989). Thus, the Vel'may terrane can be considered as a possible marker of the AACM boundary. This work was supported

  13. The Late Miocene Quaternary Antofalla volcanic complex, southern Puna, NW Argentina: Protracted history, diverse petrology, and economic potential

    NASA Astrophysics Data System (ADS)

    Richards, Jeremy P.; Ullrich, Thomas; Kerrich, Robert

    2006-04-01

    The Antofalla volcanic complex (AVC) is located on the southern Puna plateau of NW Argentina, ˜100 km east of the main axis of the Cordillera Occidental volcanic arc. It lies on the NW-SE Archibarca lineament, one of several transverse structures that cut across the Andes from Chile, and divert arc magmatism in SE-trending fingers across the Puna. 40Ar/ 39Ar dating of volcanic products from the AVC reveals a protracted magmatic history from 10.9 to ≤ 1.6 Ma. Initial volcanism was characterized by eruption of voluminous rhyolitic ignimbrites, deposited directly onto exposed crystalline basement and supracrustal sedimentary rocks. These rhyolites record significant geochemical evidence for crustal contamination, or derivation by crustal melting, which decreases upwards through the pyroclastic sequence. They were followed by extrusion of potassic lavas of the shoshonite-latite-trachydacite suite from 10.1 to 9.5 Ma. Subsequent magmatism (9.1-1.6 Ma) was of basaltic andesite-andesite-dacite composition, with localized, smaller volume, dacitic and rhyolitic ignimbrites. Monogenetic basaltic andesite cinder cones and lava flows were erupted in the Quaternary in response to a change to transtensional tectonics in the Puna. The volcanic sequence is interpreted to record the early development of a lower crustal MASH zone at ˜11 Ma, where mantle-derived arc magmas interacted extensively with felsic lower crustal rocks to produce evolved shoshonitic compositions, and crustal melts that erupted to form rhyolitic ignimbrites (common at this time throughout the Puna). After establishment of a steady-state MASH zone by ˜9 Ma, subsequent basaltic andesite-andesite magmas show less evidence of felsic crustal contamination, and may have developed largely by interaction with previous ultramafic-mafic fractionates of early magmas in the lower crust. More felsic dacitic magmas appear to have evolved largely by fractional crystallization from basaltic andesites and andesites, with

  14. Petrology of the Guenfalabo ring-complex: An example of a complete series along the Cameroon Volcanic Line (CVL), Cameroon

    NASA Astrophysics Data System (ADS)

    Donald Ngonge, E.; Hollanda, Maria Helena B. M.; Nsifa, E. Nkonguin; Tchoua, Felix M.

    2014-08-01

    In the Guenfalabo ring-complex (GRC), two non-comagmatic rock suites have been identified as a result of two volcanic episodes: Suite 1 (68.8 ± 1.7 Ma by K/Ar on trachyte) of peralkaline trachytes and pantellerites cogenetic with alkaline syenites, granites and rhyolitic flows and tuffs; Suite 2 (62 ± 2 Ma by K/Ar on basalt), a bimodal and complete series of alkali olivine basalts and associated microgabbro dykes, diorites, syenites and granites, cross-cutting the former. Kaersutite in the trachytes of Suite 1 has mantle-derived signatures: TiO2 > 4%, MgO < 15%, FeO > 8%, Ti = 0.63 c.p.f.u. and Al = 2, characteristic of kaersutites of HP and HT origin: 13-23 kbar, 1100-1220 °C. The trachytes are probably products of FC of a basaltic parent that did not attain higher crustal levels. The Suite 1 rocks are enriched in Rb, K, Zr, Nb, LREE, alkalis, and (Ce/Yb)N = 7-15 probably due to some effect of metasomatism during the magma ascension. Fe-Ti enrichment is corroborated by the presence of ferropseudobrookite-ilmenite-ulvospinel in the syenites and ilmenite in the pantellerite. The Rb/Ba > 1 in the trachytes (2.44, 26.7), pantellerite (6.33), alkaline granites (0.63-1.8) and the 87Sr/86Sr in the alkaline granites (=0.74060) depict the role of AFC. The ankaramites of the Suite 2 rocks are olivine-phyric (25%), Fo85-88, have 50-52% clinopyroxene (salite), 5% plagioclase (An55-36) and 7% Fe-Ti oxides. Trace element modeling indicates an origin from a basaltic magma of about 25% PM of spinel lherzolite mixed with a magma from <1% PM of garnet lherzolite (3-4% garnet) in a proportion of 1:4. The cogenetic alkali basalts and the microgabbro-diorite-syenite-granite that constitute the Suite 2 rocks, with a Daly gap of 54% > SiO2 < 58%, result from this Early Cenozoic magmatic event. The basalts have: Zr = 225-253, Nb = 98-111, Y = 33-56, typical of FOZO, a HIMU-type OIB related magmas (Sr/Sri = 0.70202-0.7034; Nd/Nd = 0.51282-0.512545; 206Pb/204Pb = 19.13, 207Pb/204Pb = 15

  15. Geology, petrology and geochronology of the Lago Grande layered complex: Evidence for a PGE-mineralized magmatic suite in the Carajás Mineral Province, Brazil

    NASA Astrophysics Data System (ADS)

    Teixeira, Antonio Sales; Ferreira Filho, Cesar Fonseca; Giustina, Maria Emilia Schutesky Della; Araújo, Sylvia Maria; da Silva, Heloisa Helena Azevedo Barbosa

    2015-12-01

    ultramafic lithotypes render Nd model ages between 2.94 and 3.56 Ga, with variably negative ɛNd (T = 2.72 Ga) values (-0.32 to -4.25). The crystallization sequence of the intrusion and the composition of cumulus minerals, together with lithogeochemical and Nd isotopic results, are consistent with an original mantle melt contaminated with older continental crust. The contamination of mafic magma with sialic crust is also consistent with intra-plate rifting models proposed in several studies of the CMP. Lithogeochemical and isotopic data from the Lago Grande Complex may also be interpreted as the result of melting an old lithospheric mantle, and alternative models should not be disregarded. PGE mineralizations occur in chromitites and associated with base metal sulfides in the Lago Grande Complex. Chromitite has the highest PGE content (up to 10 ppm) and is characterized by high Pt/Pd ratio (4.3). Mantle-normalized profile of chromitite is highly enriched in PPGE and similar to those from Middle Group (MG) and Upper Group (UG) chromitites from the Bushveld Complex. Platinum group minerals (PGM) occur mainly at the edge of chromite crystals in the Lago Grande chromitite, consisting of arsenides and sulfo-arsenides. Sulfide-bearing harzburgite samples of the Lago Grande complex have PGE content of up to 1 ppm and low Pt/Pd (0.2-0.3) ratios. The 2722 ± 53 Ma U-Pb zircon age determined in this study for the Lago Grande Complex overlaps with the crystallization age of the Luanga Complex. Previous interpretation that the Lago Grande and Luanga layered intrusions are part of a magmatic suite (i.e., Serra Leste Magmatic Suite) is now reinforced by similar fractionation sequences, comparable petrological evolution and overlapped U-Pb zircon ages. The occurrence of the same styles of PGE mineralization in the Lago Grande and Luanga complexes, together with remarkably similar chondrite-normalized PGE profiles and PGE minerals for chromitites of both complexes, support the concept that

  16. Genesis - the middle years

    NASA Technical Reports Server (NTRS)

    Williams, K. E.; Smith, N. G.; Wiens, R. C.; Rasbach, C. E.

    2003-01-01

    Genesis is the fifth mission of the Discovery program sponsored by NASA. The objective of Genesis is the return of pristine solar wind samples to Earth to expand the understanding of how planets, asteroids, and comets were formed from our original solar nebula.

  17. Petrologic and Chemical Characterization of a Suite of Antarctic Diogenites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Mertzman, S. A.; Peng, Z. X.; Mertzman, K. R.

    2013-01-01

    The origin of diogenites, ultramafic cumulates related to eucrites, is an unresolved problem [1]. Most diogenites are orthopyroxenites, a few are harzburgites [2], and some are transitional to cumulate eucrites [1, 3]. Cumulate eucrites are gabbros formed by crystal fractionation from basaltic eucrites [4]. The consensus view is that basaltic eucrites are residual melts from global-magma-ocean crystallization on their parent asteroid [4] which is plausibly Vesta [5]. However, the petrologic and compositional characteristics of diogenites seem to preclude a magma ocean origin [1, 4]. We are doing a petrologic and chemical study of new or unusual diogenites with the ultimate goals of constraining their genesis, and the geologic evolution of Vesta.

  18. Polymetamorphic evolution of the upper part of the Iezer Complex (Leaota Massif, South Carpathians) constrained by petrological data and monazite ages

    NASA Astrophysics Data System (ADS)

    Negulescu, Elena; Săbău, Gavril; Massonne, Hans-Joachim

    2015-04-01

    The Leaota Massif in Romania consists of a flat-lying sequence of five structurally concordant units displaying mutual and partly internal lithologic and metamorphic contrasts. The lower part of the lithologic sequence is the Iezer Complex, a medium-grade psammopelitic unit with a structurally concordant thin granite sill located at its upper part. The lower limit of the granite is marked discontinuously by hornfels, also present as enclaves, which experienced intense strain and a subsequent low-pressure thermal overprint. Both granite and hornfels were affected by a medium-temperature, medium- to high-pressure event (Săbău, 2000). This event was also identified in gneisses below the hornfels. These rocks contain the assemblage garnet-phengite-chloritoid-kyanite which had overprinted an older garnet-kyanite-staurolite-biotite-muscovite assemblage. Available U-Th zircon ages indicate 472.7 ± 7.3 Ma (Balintoni et al. 2009) for the granite. Monazite geochronology (Săbău & Negulescu, 2013) reveals for the associated hornfels (1) inherited ages of 528 ± 17.86 Ma overprinted by pervasive Ordovician contact metamorphism (462 ± 4.54 Ma), slightly postdating the age of magmatic zircon in the granite, (2) Silurian to Early Devonian recrystallization episodes, and (3) a Variscan medium- to high-pressure metamorphic overprint responsible for the garnet-phengite-kyanite assemblage. New petrological and geochronological data constraining the polymetamorphic evolution of the upper part of the Iezer Complex were acquired from kyanite-garnet mylonitic gneisses made up of large garnet porphyroclasts embedded in a strongly deformed matrix. Large garnets are rich in quartz, phengite, epidote, kyanite, rutile, and ilmenite inclusions. Biotite, chlorite, apatite, monazite, and Al-cerite inclusions are also present. Garnet porphyroclasts are wrapped by laminae of small garnet - white mica - biotite - quartz or zoisite - kyanite - plagioclase alternating with bands made up of fine

  19. Petrology of Anomalous Eucrites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Peng, Z. X.; Ross, D. K.

    2015-01-01

    Most mafic achondrites can be broadly categorized as being "eucritic", that is, they are composed of a ferroan low-Ca clinopyroxene, high-Ca plagioclase and a silica phase. They are petrologically distinct from angritic basalts, which are composed of high-Ca, Al-Ti-rich clinopyroxene, Carich olivine, nearly pure anorthite and kirschsteinite, or from what might be called brachinitic basalts, which are composed of ferroan orthopyroxene and high-Ca clinopyroxene, intermediate-Ca plagioclase and ferroan olivine. Because of their similar mineralogy and composition, eucrite-like mafic achondrites formed on compositionally similar asteroids under similar conditions of temperature, pressure and oxygen fugacity. Some of them have distinctive isotopic compositions and petrologic characteristics that demonstrate formation on asteroids different from the parent of the HED clan (e.g., Ibitira, Northwest Africa (NWA) 011). Others show smaller oxygen isotopic distinctions but are otherwise petrologically and compositionally indistinguishable from basaltic eucrites (e.g., Pasamonte, Pecora Escarpment (PCA) 91007). The degree of uniformity in delta O-17 of eucrites and diogenites is one piece of evidence considered to favor of a magma-ocean scenario for their petrogenesis. Given that the O isotopic differences separating Pasamonte and PCA 91007 from other eucrites are small, and that there is an absence of other distinguishing characteristics, a legitimate question is: Did the HED parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? We are initiating a program of study of anomalous eucrite-like achondrites as one part of our effort to seek a resolution of this issue. Here we present preliminary petrologic information on Asuka (A-) 881394, Elephant Moraine (EET) 87520 and EET 87542. We will have studied several more by conference time.

  20. Petrology of blueschist from the Western Himalaya (Ladakh, NW India): Exploring the complex behavior of a lawsonite-bearing system in a paleo-accretionary setting

    NASA Astrophysics Data System (ADS)

    Groppo, Chiara; Rolfo, Franco; Sachan, Himanshu K.; Rai, Santosh K.

    2016-05-01

    Although the Himalaya is the archetype of collisional orogens, formed as a consequence of the closure of the Neo-Tethyan ocean separating India from Asia, high-pressure metamorphic rocks are rare. Beside few eclogites, corresponding to the metamorphosed continental Indian crust dragged below Asia or underthrusted beneath southern Tibet, blueschists occur seldom along the Yarlung-Tsangpo Suture zone, i.e. the suture marking the India-Asia collision. These blueschists, mostly interpreted as related to paleo-accretionary prisms formed in response to the subduction of the Neo-Tethyan ocean below the Asian plate, are crucial for constraining the evolution of the India-Asia convergence zone during the closure of the Neo-Tethyan Ocean. In the Western Himalaya, the best occurrence of blueschist is that of the Sapi-Shergol Ophiolitic Mélange in Ladakh. This unit is dominated by volcanoclastic sequences rich in mafic material with subordinate interbedding of metasediments, characterized by very fresh lawsonite blueschist-facies assemblages. In this paper, the lawsonite blueschist-facies metasediments have been petrologically investigated with the aims of (i) constraining the P-T evolution of the Sapi-Shergol Ophiolitic Mélange, (ii) evaluating the influence of Fe2O3 and of H2O on the stability of the high-pressure mineral assemblages, (iii) understanding the processes controlling lawsonite formation and preservation, and (iv) interpreting the P-T evolution of the Sapi-Shergol blueschists in the framework of India-Asia collision. Our results indicate that (i) the Sapi-Shergol blueschists experienced a cold subduction history along a low thermal gradient, up to peak conditions of ca. 470 °C, 19 kbar; furthermore, in order to preserve lawsonite in the studied lithologies, exhumation must have been coupled with significant cooling, i.e. the resulting P-T path is characterized by a clockwise hairpin loop along low thermal gradients (< 8-9 °C/km); (ii) the presence of ferric

  1. Genesis and evolution of mafic and felsic magmas at Quaternary volcanoes within the Main Ethiopian Rift: Insights from Gedemsa and Fanta 'Ale complexes

    NASA Astrophysics Data System (ADS)

    Giordano, F.; D'Antonio, M.; Civetta, L.; Tonarini, S.; Orsi, G.; Ayalew, D.; Yirgu, G.; Dell'Erba, F.; Di Vito, M. A.; Isaia, R.

    2014-02-01

    This paper presents the results of an investigation carried out on young volcanic rocks from the Gedemsa and Fanta 'Ale complexes, located in the Main Ethiopian Rift, the site of an intense magmatism since Eocene-Oligocene. The earlier NW-SE direction of extension of the Rift, which generated NE-SW trending faults, rotated around E-W in Quaternary times, and produced the still active N to N-NE Wonji Fault System. The Gedemsa volcano is located in the central part of the Ethiopian Rift, about 100 km SE of Addis Ababa. It is characterized by a wide central caldera, about 8 km in diameter. The general stratigraphic sequence in the area includes, from base upwards, rift-floor ignimbrites, pantelleritic and subordinate trachytic pyroclastic deposits and lava flows and domes, and widespread basaltic deposits. The Fanta 'Ale volcanic complex is located in the northern part of the Main Ethiopian Rift, where the Afar depression begins. It is characterized by a summit caldera of which the diameter is about 4 km. This volcano erupted trachytic and rhyolitic lavas, whereas the most diffuse unit is an ignimbrite related to the caldera collapse. Explosive activity has occurred inside and outside the caldera, forming tuff cones and thick pumice-fallout deposits. The only mafic unit is represented by a basaltic eruption that occurred in 1870 AD. Historical eruptions and intense fumarolic activity are evidence for the persistence activity of the Fanta 'Ale in this part of the Main Ethiopian Rift. New geochemical and Sr-Nd-Pb isotope data on representative samples from Gedemsa and Fanta 'Ale volcanoes are presented and discussed in order to shed light on the genesis of mafic and felsic magmas, the genetic link between them, and their possible interaction with the local crust. Volcanic rocks show a typical mafic-felsic bi-modal distribution with few intermediate terms (Daly Gap), as observed at regional scale along the Main Ethiopian Rift as well as on the plateau. Geochemical data

  2. Genesis of emulsion texture due to magma mixing: a case study from Chotanagpur Granite Gneiss Complex of Eastern India

    NASA Astrophysics Data System (ADS)

    Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor

    2016-04-01

    The emulsion texture is a rare magma mixing feature in which rounded bodies of one magmatic phase remain dispersed in the other coherent phase (Freundt and Schmincke, 1992). This type of special texture in hybrid rocks can significantly contribute toward understanding the mechanisms facilitating magma mixing and magma chamber dynamics involving two disparate magmas as the exact processes by which mixing occurs still remain unclear. Recent developments in microfluidics have greatly helped us to understand the complex processes governing magma mixing occurring at micro-level. Presented work uses some of the results obtained from microfluidic experiments with a view to understand the formation mechanism of emulsions preserved in the hybrid rocks of the Ghansura Rhyolite Dome (GRD) of Proterozoic Chotanagpur Granite Gneiss Complex (CGGC), Eastern India. The GRD has preserved hybrid rocks displaying emulsion texture that formed due to the interaction of a phenocryst-rich basaltic magma and host rhyolite magma. The emulsions are more or less spherical in shape and dominantly composed of amphibole having biotite rinds set in a matrix of biotite, plagioclase, K-feldspar and quartz. Amphibole compositions were determined from the core of the emulsions to the rim with a view to check for cationic substitutions. The amphibole constituting the emulsions is actinolite in composition, and commonly shows tschermakite (Ts) and pargasite (Prg) substitutions. From petrographical and mineral-chemical analyses we infer that when mafic magma, containing phenocrysts of augite, came in contact with felsic magma, diffusion of cations like H+, Al3+and others occurred from the felsic to the mafic system. These cations reacted with the clinopyroxene phenocrysts in the mafic magma to form amphibole (actinolite) crystals. The formation of amphibole crystals in the mafic system greatly increased the viscosity of the system allowing the amphibole crystals to venture into the adjacent felsic

  3. Genesis Failure Investigation Report

    NASA Technical Reports Server (NTRS)

    Klein, John

    2004-01-01

    The-Genesis mission to collect solar-wind samples and return them to Earth for detailed analysis proceeded successfully for 3.5 years. During reentry on September 8, 2004, a failure in the entry, descent and landing sequence resulted in a crash landing of the Genesis sample return capsule. This document describes the findings of the avionics sub-team that supported the accident investigation of the JPL Failure Review Board.

  4. Generalized galilean genesis

    SciTech Connect

    Nishi, Sakine; Kobayashi, Tsutomu

    2015-03-31

    The galilean genesis scenario is an alternative to inflation in which the universe starts expanding from Minkowski in the asymptotic past by violating the null energy condition stably. Several concrete models of galilean genesis have been constructed so far within the context of galileon-type scalar-field theories. We give a generic, unified description of the galilean genesis scenario in terms of the Horndeski theory, i.e., the most general scalar-tensor theory with second-order field equations. In doing so we generalize the previous models to have a new parameter (denoted by α) which results in controlling the evolution of the Hubble rate. The background dynamics is investigated to show that the generalized galilean genesis solution is an attractor, similarly to the original model. We also study the nature of primordial perturbations in the generalized galilean genesis scenario. In all the models described by our generalized genesis Lagrangian, amplification of tensor perturbations does not occur as opposed to what happens in quasi-de Sitter inflation. We show that the spectral index of curvature perturbations is determined solely from the parameter α and does not depend on the other details of the model. In contrast to the original model, a nearly scale-invariant spectrum of curvature perturbations is obtained for a specific choice of α.

  5. Origin of rhythmic anorthositic-pyroxenitic layering in the Damiao anorthosite complex, China: Implications for late-stage fractional crystallization and genesis of Fe-Ti oxide ores

    NASA Astrophysics Data System (ADS)

    Li, Li-Xing; Li, Hou-Min; Li, Yong-Zhan; Yao, Tong; Yang, Xiu-Qing; Chen, Jing

    2015-12-01

    The ∼1.7 Ga Damiao anorthosite complex (DAC) in the North China Craton contains abundant Ti-magnetite-dominated ore deposits. Both the Fe-Ti-P-rich silicate rocks and massive Fe-Ti-(P) ores occur as discordant late-stage dikes cross-cutting early-stage anorthosites with irregular but sharp boundaries. Field and petrographic observations indicate that some late-stage dikes are composed of unique oxide-apatite gabbronorites (OAGNs), whereas others comprise well-developed alternating late-stage anorthosites and Fe-Ti-P-rich pyroxenites defining rhythmic layers. Massive Fe-Ti-(P) ores are closely related to the Fe-Ti-P-rich pyroxenites. Plagioclase and whole-rock compositions of different rock types were analyzed to constrain the late-stage magma evolution and genesis of the Fe-Ti oxide ores. The similar mineralogical assemblages, REE and HFSE patterns suggest that the different rock types formed by differentiation from a common parental magma. Early-stage anorthosites are characterized by positive Eu anomalies and low REE contents, whereas the late-stage dike-like rocks display no significant Eu anomalies and high REE contents. Plagioclase compositions in the late-stage rocks show a decrease of An contents when compared to that of the early-stage rocks. Based on field relations, petrography and well-defined linear compositional trends, the sequence of crystallization is inferred as: early-stage anorthosites + leuconorites + norites, OAGNs, late-stage anorthosites + Fe-Ti-P-rich pyroxenites + massive Fe-Ti-(P) ores, and massive Fe-Ti-(P) ores. The OAGNs which underwent relatively rapid crystallization represent an early phase during the residual magma evolution after anorthosite separation, whereas the rhythmic layers formed by slow but extensive fractional crystallization of interstitial melt. High solubility of phosphorous played an important role in the formation of rhythmic layering. Massive Fe-Ti-(P) ores crystallized and segregated directly from the magma of Fe

  6. Review and update of the applications of organic petrology: Part 2, geological and multidisciplinary applications

    USGS Publications Warehouse

    Suarez-Ruiz, Isabel; Flores, Deolinda; Mendonça Filho, João Graciano; Hackley, Paul C.

    2012-01-01

    The present paper is focused on organic petrology applied to unconventional and multidisciplinary investigations and is the second part of a two part review that describes the geological applications and uses of this branch of earth sciences. Therefore, this paper reviews the use of organic petrology in investigations of: (i) ore genesis when organic matter occurs associated with mineralization; (ii) the behavior of organic matter in coal fires (self-heating and self-combustion); (iii) environmental and anthropogenic impacts associated with the management and industrial utilization of coal; (iv) archeology and the nature and geographical provenance of objects of organic nature such as jet, amber, other artifacts and coal from archeological sites; and (v) forensic science connected with criminal behavior or disasters. This second part of the review outlines the most recent research and applications of organic petrology in those fields.

  7. Genesis Preliminary Examination Plans

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, E. K.

    2004-01-01

    The purpose of preliminary examination of the Genesis sample collectors is to provide information on the condition and availability of collector materials to the science community as a basis for allocation requests. Similarly, the information will be used by the Genesis Sample Allocation sub-committee of CAPTEM to determine the optimum allocation scheme, and by the Genesis Curator to determine the processing sequence for allocation production. The plan includes a decision process and detailed examination and documentation protocol for whole arrays and individual collectors (wafers, concentrator targets, bulk metallic glass, gold foil, and polished aluminum). It also includes a plan for communicating the information obtained to the scientific community. The plan does not include a detailed plan for preliminary examination of the SRC lid foil collectors, the process for removal of individual collectors from their frames, or for the subsequent subdivision of collector materials for allocation.

  8. Genesis Radiation Environment

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Altstatt, Richard L.; Skipworth, William C.

    2007-01-01

    The Genesis spacecraft launched on 8 August 2001 sampled solar wind environments at L1 from 2001 to 2004. After the Science Capsule door was opened, numerous foils and samples were exposed to the various solar wind environments during periods including slow solar wind from the streamer belts, fast solar wind flows from coronal holes, and coronal mass ejections. The Survey and Examination of Eroded Returned Surfaces (SEERS) program led by NASA's Space Environments and Effects program had initiated access for the space materials community to the remaining Science Capsule hardware after the science samples had been removed for evaluation of materials exposure to the space environment. This presentation will describe the process used to generate a reference radiation Genesis Radiation Environment developed for the SEERS program for use by the materials science community in their analyses of the Genesis hardware.

  9. Petrology of impactites

    NASA Astrophysics Data System (ADS)

    Fel'Dman, Vilen I.

    The book reviews results from petrological studies of astroblemes and the astrobleme-forming structures, impactites. Consideration is given to the distribution of astroblemes on earth in time and space and to the morphology and internal structure of astroblemes, as well as to physical processes responsible for the formation of impactites. A catalog of all known astroblemes and their characteristics is constructed. Attention is given to the geochemical, petrographical, and geophysical characteristics of impactites, and a classification scheme is devised by which impactites are classified according to four characteristics: the source of energy in an impactite formation, the environment in which the impactite was formed, the mechanism of impactite formation, and the pressure/temperature parameters at the moment of impactite formation.

  10. Europa's petrological thermal history

    NASA Technical Reports Server (NTRS)

    Ransford, G. A.; Finnerty, A. A.; Collerson, K. D.

    1981-01-01

    A path of geophysical development which takes into account the petrological sequence is presented to describe the thermal evolution of Europa. On the basis of considerations of the likely temperature-pressure conditions in the Europa zone of the circumjovian nebula during the condensation of the satellite on the one hand and of the early thermal evolution on the other, it is argued that most of the water of Europa can be in the form of hydrated silicates in a thick convective boundary layer or throughout the body of the satellite. Such silicates would include the minerals chlorite and/or serpentine, and brucite, and could be maintained in hydrated states by solid state convection within the body. The model predicts that the ice layer on the surface of Europa is considerably thinner than the 150 km that had been estimated before the Voyager mission.

  11. Petrology at Princeton

    NASA Astrophysics Data System (ADS)

    Hollister, L. S.

    2003-12-01

    Igneous and Metamorphic Petrology at Princeton has evolved from a course f or junior or senior majors to a course that targets sophomores who might major in geology. The prerequisite is one prior course in geology. The course is constructed around a one-week series of field exercises in the Rio Grand rift of New Mexico. These are taken during our fall break. During the field exercises they collect metamorphic or volcanic rocks that form the basis of a project that they work on in the second half of the semester. They make thin sections of their rocks, learn some microscopy and mineralogy as they examine them, and prepare a final paper with the structure of a research article. The students give oral reports in an "AGU like" session. Part of their grade is based on their questioning of their peers. Prior to the one-week trip, the students are taken on half or full-day field trips to central Atlantic rift features in the vicinity of Princeton. These trips and related labs prepare them for the trip to New Mexico. They must keep a notebook in which they record their field observations. The notebooks for the one-week trip are evaluated and the grade is a significant fraction of the final grade. This course began as an experiment, which was driven by a need to increase the number of majors in Geosciences. The course works best for class sizes of 6 to 10; one or two do not continue in geology, and one or two are already majoring in other sciences. Veterans of former classes come as assistants on the one week trip. Thus, the students considering majoring in Geosciences are mentored by the older students. And the veterans add to their petrology and mineralogy education through instruction of the younger students. The trip is expensive. Costs are covered by income from endowed funds set up to provide field experiences for undergraduates. This course helps tremendously in introducing eastern students to the geology that is so dramatically displayed in the west, and that is

  12. Petrology of metamorphic rocks

    SciTech Connect

    Suk, M.

    1983-01-01

    ''Petrology of Metamorphic Rocks'' reviews Central European opinions about the origin and formation of metamorphic rocks and their genetic systems, confronting the works of such distinguished European scientists as Rosenbusch, Becke, Niggli, Sander, Eskola, Barth and others with present-day knowledge and the results of Soviet and American investigations. The initial chapters discuss the processes that give rise to metamorphic rocks, and the main differences between regional metamorphism and other types of alterations, the emphasis being laid on the material characteristic of the processes of metamorphism, metasomatism and ultrametamorphism. Further chapters give a brief characterization of research methods, together with a detailed genetic classification based on the division of primary rocks into igneous rocks, sediments and ore materials. The effects of metamorphic alterations and those of the properties of the primary rocks are analyzed on the basis of examples taken chiefly from the Bohemian Massif, the West Carpathians, other parts of the European Variscides, from the crystalline Scandinavian Shelf in Norway and Finland, and from the Alps. Typical examples are documented by a number of charts, photographs and petrographical - particularly petrochemical - data.

  13. Geology and petrology of the Simav Magmatic Complex (NW Anatolia) and its comparison with the Oligo-Miocene granitoids in NW Anatolia: implications on Tertiary tectonic evolution of the region

    NASA Astrophysics Data System (ADS)

    Akay, Erhan

    2009-10-01

    The Oligo-Miocene granitic plutons and their related volcanic-subvolcanic successions form a NW-SE trending magmatic belt along the northern border of the Menderes Massif. This belt evolved within a nappe package consisting of the Menderes metamorphics, Sakarya Continent, Afyon Zone and Tavşanlı Zone and also intruded this nappe package. The Ezine, Evciler, Eybek, Kozak, Alaçam, Koyunoba, Eğrigöz and the Baklan plutons emplaced along this belt and show similarities in their internal structures, emplacement mechanisms, and petrological characteristics. These different granitic plutons cut and stitch various combinations of the nappe package of the above-mentioned tectonic belts, and evolved during and following the Alpine collision. They all show characteristic map patterns of shallow-seated plutons and range from granite to monzogranite. The granitic plutons display calc-alkaline, I-type and post-collisional geochemical characteristics. The Eğrigöz, Koyunoba plutons and their subvolcanic-volcanic phases (Simav Magmatic Complex) were studied in detail. The geochemical characteristics and field occurences of the Simav Magmatic Complex were compared to the other magmatic associations in western Anatolia and it was determined that it is of collisional origin and not related to an extensional tectonic regime as suggested in some recent studies.

  14. Genesis Field Recovery

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.

    2005-01-01

    The Genesis mission returned to Earth on September 8, 2004 after a nearly flawless three-year mission to collect solar matter. The intent was to deploy a drogue chute and parafoil high over the Utah desert and to catch the fragile payload capsule in mid-air by helicopter. The capsule would then be opened in a clean-room constructed for that purpose at UTTR, and a nitrogen purge was to be installed before transporting the science canister to JSC. Unfortunately, both chutes failed to deploy, causing the capsule to fall to the desert floor at a speed of nearly 200 MPH. Still, Genesis represents a milestone in the US space program, comprising the first sample return since the Apollo Missions as well as the first return of materials exposed to the space environment outside of low Earth orbit and beyond the Earth s magnetosphere for an extended period. We have no other comparable materials in all of our collections on Earth. The goal of the Genesis Mission was to collect a representative sample of the composition of the solar wind and thus, the solar nebula from which our solar system originated. This was done by allowing the naturally accelerated species to implant shallowly in the surfaces of ultra-pure, ultra-clean collector materials. These collectors included single crystal silicon (FZ and CZ), sapphire, silicon carbide; those materials coated with aluminum, silicon, diamond like carbon, and gold; and isotopically enriched polycrystalline diamond and amorphous carbon. The majority of these materials were distributed on five collector arrays. Three of the materials were housed in an electrostatic concentrator designed to increase the flux of low-mass ions. There was also a two-inch diameter bulk metallic glass collector and a gold foil, polished aluminum, and molybdenum coated platinum foil collector. An excellent review of the Genesis collector materials is offered in reference [1].

  15. Genesis Noble Gas Measurements

    NASA Technical Reports Server (NTRS)

    Hohenberg, Charles M.

    2005-01-01

    The original thrust of our Genesis funding was to extend and refine the noble gas analytical capabilities of this laboratory to improve the precision and accuracy of noble gas measurements in order to optimize the scientific return from the Genesis Mission. This process involved both instrumental improvement (supplemented by a SRLIDAP instrument grant) and refinement of technique. The Genesis landing mishap shifted our emphasis to the irregular aluminum heat shield material from the flat collector wafers. This has required redesign of our laser extraction cells to accommodate the longer focal lengths required for laser extraction from non-flat surfaces. Extraction of noble gases from solid aluminum surfaces, rather than thin coatings on transparent substrates has required refinement of controlled-depth laser ablation techniques. Both of these bring new problems, both with potentially higher blanks form larger laser cells and the larger quantities of evaporated aluminum which can coat the sapphire entrance ports. This is mainly a problem for the heavy noble gases where larger extraction areas are required, necessitating the new aluminum vapor containment techniques described below. With the Genesis Mission came three new multiple multiplier noble gas mass spectrometers to this laboratory, one built solely by us (Supergnome-M), one built in collaboration with Nu-Instruments (Noblesse), and one built in collaboration with GVI (Helix). All of these have multiple multiplier detection sections with the Nu-Instruments using a pair of electrostatic quad lenses for isotope spacing and the other two using mechanically adjustable positions for the electron multipliers. The Supergnome-M and Noblesse are installed and running. The GVI instrument was delivered a year late (in March 2005) and is yet to be installed by GVI. As with all new instruments there were some initial development issues, some of which are still outstanding. The most serious of these are performance issues

  16. Genesis Recovery Processing

    NASA Technical Reports Server (NTRS)

    Stansbery, E. K.

    2005-01-01

    The Genesis spacecraft, launched in August 2001 to collect samples of the solar wind, returned to Earth on 8 September 2004. The Sample Return Capsule (SRC) failed to deploy its drogue parachute and parafoil and subsequently impacted the Utah Test and Training Range (UTTR) at an estimated 310 kph (193 mph). The goal of the Genesis mission to collect and return samples of the solar wind for precise elemental and isotopic analysis provides the scientific community with a unique set of materials to aid in understanding the origin of our solar system. The spacecraft orbited the Earth-Sun L1 point for 29 months exposing a suite of fifteen types of ultrapure, ultraclean materials in several different locations. Most of the materials were mounted on fixed or deployable wafer panels called collector arrays . A few materials were mounted as targets in the focal spot of an electrostatic mirror (the concentrator ). Other materials were strategically placed to maximize the area for solar-wind collection.

  17. 3D numerical modeling of mantle flow, crustal dynamics and magma genesis associated with slab roll-back and tearing: The eastern Mediterranean case

    NASA Astrophysics Data System (ADS)

    Menant, Armel; Sternai, Pietro; Jolivet, Laurent; Guillou-Frottier, Laurent; Gerya, Taras

    2016-05-01

    Interactions between subduction dynamics and magma genesis have been intensely investigated, resulting in several conceptual models derived from geological, geochemical and geophysical data. To provide physico-chemical constraints on these conceptual models, self-consistent numerical simulations containing testable thermo-mechanical parameters are required, especially considering the three-dimensional (3D) natural complexity of subduction systems. Here, we use a 3D high-resolution petrological and thermo-mechanical numerical model to quantify the relative contribution of oceanic and continental subduction/collision, slab roll-back and tearing to magma genesis and transport processes. Our modeling results suggest that the space and time distribution and composition of magmas in the overriding plate is controlled by the 3D slab dynamics and related asthenospheric flow. Moreover, the decrease of the bulk lithospheric strength induced by mantle- and crust-derived magmas promotes the propagation of strike-slip and extensional fault zones through the overriding crust as response to slab roll-back and continental collision. Reduction of the lithosphere/asthenosphere rheological contrast by lithospheric weakening also favors the transmission of velocities from the flowing mantle to the crust. Similarities between our modeling results and the late Cenozoic tectonic and magmatic evolution across the eastern Mediterranean region suggest an efficient control of mantle flow on the magmatic activity in this region, which in turn promotes lithospheric deformation by mantle drag via melt-induced weakening effects.

  18. Genesis Trajectory Design

    NASA Technical Reports Server (NTRS)

    Bell, Julia L.; Lo, Martin W.; Wilson, Roby S.

    2000-01-01

    The Genesis mission will launch in 2001, sending the spacecraft into a halo orbit about the Sun-Earth L1 point to collect and return solar wind samples to the Earth for analysis in 2003. One of the most constraining aspects of the mission design is the requirement to return to the designated landing site (the Utah Test and Training Range, UTTR) during daylight hours. The ongoing mission design has led the development of a family of solutions that characterize a broad range of conditions at Earth entry. Characterizing this family provides insight into the possible existence of additional trajectories while also helping to narrow the search space by indicating where additional solutions are unlikely to exist; this contributes to a more efficient utilization of mission design resources.

  19. Early Jurassic subduction of the Paleo-Pacific Ocean in NE China: Petrologic and geochemical evidence from the Tumen mafic intrusive complex

    NASA Astrophysics Data System (ADS)

    Guo, Feng; Li, Hongxia; Fan, Weiming; Li, Jingyan; Zhao, Liang; Huang, Miwei; Xu, Wenliang

    2015-05-01

    Subduction of the Paleo-Pacific Oceanic Plate is widely considered to have caused extensive Mesozoic magmatism, lithospheric deformation and mineralization in East Asia. However, it is still unclear when this subduction began. Here we report an Early Jurassic (~ 187 Ma) mafic intrusive complex (including olivine norite, gabbro, and diorite) from the Tumen area in NE China. The olivine norite contains a mineral assemblage of olivine, pyroxene, Ca-plagioclase, and hornblende that crystallized in a water-saturated parental magma. The rocks in the complex show variable degrees of plagioclase and ferromagnesian mineral accumulation as reflected by positive Sr and Eu anomalies in primitive mantle-normalized incompatible element patterns. Mass-balance calculations indicate that the parental magma was calc-alkaline with arc-type trace element features (i.e., large ion incompatible and light rare earth element enrichment and Nb-Ta depletion). It also had Sr-Nd-Hf isotopic compositions (87Sr/86Sr(i) = 0.7042 to 0.7044, εNd(t) = + 2.5 to + 3.5 and εHf(t) = + 8.4 to + 10.5) similar to those of modern arc basalts. The parental magma was likely derived from 5 to 20% melting of a mantle wedge metasomatized by an addition of 3-4% hydrous sediment melt from the subducting Paleo-Pacific Oceanic slab. The Tumen mafic intrusive complex, together with other contemporaneous mafic intrusions, I-type granitoids, and felsic lavas, constitutes an Early Jurassic N-S-trending arc magmatic belt that was formed by westward subduction of the Paleo-Pacific Ocean.

  20. The mafic-ultramafic complex of Aniyapuram, Cauvery Suture Zone, southern India: Petrological and geochemical constraints for Neoarchean suprasubduction zone tectonics

    NASA Astrophysics Data System (ADS)

    Yellappa, T.; Venkatasivappa, V.; Koizumi, T.; Chetty, T. R. K.; Santosh, M.; Tsunogae, T.

    2014-12-01

    Several Precambrian mafic-ultramafic complexes occur along the Cauvery Suture Zone (CSZ) in Southern Granulite Terrain, India. Their origin, magmatic evolution and relationship with the associated high-grade rocks have not been resolved. The Aniyapuram Mafic-Ultramafic Complex (AMUC), the focus of the present study in southern part of the CSZ, is dominantly composed of peridotites, pyroxenites, gabbros, metagabbros/mafic granulites, hornblendites, amphibolites, plagiogranites, felsic granulites and ferruginous cherts. The rock types in the AMUC are structurally emplaced within hornblende gneiss (TTG) basement rocks and are highly deformed. The geochemical signature of the amphibolites indicates tholeiitic affinity for the protolith with magma generation in island arc-setting. N-MORB normalized pattern of the amphibolites show depletion in HFS-elements (P, Zr, Sm, Ti, and Y) and enrichment of LIL-elements (Rb, Ba, Th, Sr) with negative Nb anomalies suggesting involvement of subduction component in the depleted mantle source and formation in a supra-subduction zone tectonic setting. Our new results when correlated with the available age data suggest that the lithological association of AMUC represent the remnants of the Neoarchean oceanic lithosphere.

  1. Field, petrologic and detrital zircon study of the Kings sequence and Calaveras complex, Southern Lake Kaweah Roof Pendant, Tulare County, California

    NASA Astrophysics Data System (ADS)

    Buchen, Christopher T.

    U-Pb dating of detrital zircon grains separated from elastic sedimentary rocks is combined with field, petrographic and geochemical data to reconstruct the geologic history of Mesozoic rocks exposed at the southern end of the Lake Kaweah metamorphic pendant, western Sierra Nevada. Identification of rocks exposed at Limekiln Hill, Kern County, CA, as belonging to the Calaveras complex and Kings sequence was confirmed. Detrital zircon populations from two Calaveras complex samples provide Permo-Triassic maximum depositional ages (MDA) and reveal a Laurentian provenance indicating that continental accretion of the northwest-trending Kings-Kaweah ophiolite belt was in process prior to the Jurassic Period. Rock types including radiolarian metachert, metachert-argillite, and calc-silicate rocks with marble lenses are interpreted as formed in a hemipelagic environment of siliceous radiolarian deposition, punctuated by extended episodes of lime-mud gravity flows mixing with siliceous ooze forming cafe-silicate protoliths and limestone olistoliths forming marble lenses. Two samples of the overlying Kings sequence turbidites yield detrital zircons with an MDA of 181.4 +/-3.0 Ma and an interpreted provenance similar to other Jurassic metasediments found in the Yokohl Valley, Sequoia and Boyden Cave roof pendants. Age peaks indicative of Jurassic erg heritage are also present. In contrast, detrital zircon samples from the Sequoia and Slate Mountain roof pendants bear age-probability distributions interpreted as characteristic of the Snow Lake block, a tectonic sliver offset from the Paleozoic miogeocline.

  2. The petrology of high-Mg dikes from the Beartooth Mountains, Montana - A search for the parent magma of the Stillwater Complex

    NASA Technical Reports Server (NTRS)

    Longhi, J.; Wooden, J. L.; Coppinger, K. D.

    1983-01-01

    Six geochemically distinct groups of Precambrian high-Mg dikes have been examined to determine if any could have been a sample of or closely related to the parent magma of the Stillwater Complex. Only two groups have sufficiently magnesian olivine and orthopyroxene, but neither of these has sufficiently calcic plagioclase. In terms of major elements there appear to be only two distinct magma types: one has a high orthopyroxene component and is petrographically similar to noritic dikes and sills near the Great Dyke of Zimbabwe and the Bushveld Complex of South Africa; the other is similar to primitive tholeiites with higher plagioclase and diopside components than the first. All of the groups are enriched in light-REE and have unusually high K2O concentrations. Model calculations indicate that crustal contamination of fractionating komatiitic magmas is consistent with the major and trace element characteristics of the first magma type. Less extensive contamination of komatiitic magmas may produce the parental magmas of the large layered intrusions.

  3. Petrology and tectonic significance of gabbros, tonalites, shoshonites, and anorthosites in a late Paleozoic arc-root complex in the Wrangellia Terrane, southern Alaska

    SciTech Connect

    Beard, J.S. ); Barker, F. )

    1989-11-01

    Plutonic rocks intrusive into the late Paleozoic Tetelna Formation of southern Alaska are the underpinnings of the late Paleozoic Skolai arc of the Wrangellia Terrane. There are four groups of intrusive rocks within the Skolai arc: (1) Gabbro-diorite plutons that contain gabbroic to anorthositic cumulates along with a differentiated series of gabbros and diorites of basaltic to andesitic composition; (2) Silicic intrusions including tonalite, granodiorite, and granite; (3) Monzonitic to syenitic plutonic rocks of the Ahtell complex and related dikes and sills; (4) Fault-bounded bytownite anorthosite of uncertain age and association. These anorthosites may be related to post-Skolai, Nikolai Greenstone magmatism. The silicic rocks yield discordant U-Pb zircon ages of 290-320 Ma (early to late Pennsylvanian). The monzonitic rocks of the Ahtell complex have shoshonitic chemistry. Similar shoshonitic rocks are widespread in both the Wrangellia terrane and the neighboring Alexander terrane and intrude the contact between the two. In modern oceanic arcs, shoshonitic rocks are typically associated with tectonic instability occurring during the initial stages of subduction or just prior to or during termination or flip of an established subduction zone. The nature of any tectonic instability which may have led to the cessation of subduction in the Skolai arc is unclear. Possibilities include collision of the arc with a ridge, an oceanic plateau, another arc, or a continental fragment. One possibility is that the shoshonitic magmatism marks the late Paleozoic amalgamation of Wrangellia and the Alexander terrane. The scarcity of arc rocks predating the shoshonites in the Alexander terrane supports this possibility, but structural corroboration is lacking.

  4. Geological and petrological aspects of Ni-Cu-PGE mineralization in the early Paleoproterozoic Monchegorsk layered mafic-ultramafic complex, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Sharkov, E. V.; Chistyakov, A. V.

    2014-05-01

    The Early Paleoproterozoic Monchegorsk Complex comprises two independent large layered mafic-ultramafic intrusions: the Monchegorsk pluton and the Main Range massif formed about 2.50 and 2.46 Ga ago, respectively. They are composed of similar cumulates, though they differ somewhat in the isotopic parameters of rocks, cumulate stratigraphy and derived from siliceous high-Mg series melts that arose in the same large long-living volcanic center. The economic syngenetic Ni-Cu-PGE sulfide mineralization related to the earlier Monchegorsk pluton is represented by two types of ores. The first type, pertaining to fractionation of the primary melt, is opposite to the reef formed due to injection of a special ore-bearing melt into the solidifying intrusive chamber. The primary magmatic mineralization is largely composed of Ni-Fe-Cu sulfides and Pd-Pt sulfides, bismuthides, and tellurides. Only small PGE and probably chromite occurrences are related to the Main Range massif. In the Mid-Paleoproterozoic (2.0-1.9 Ga), the complex was transformed into a collage of tectonic blocks confined to the regional fault zone. The Monchegorsk pluton was retained better, and only rocks of its southern framework were involved into tectonic and metamorphic reworking with the formation of economic metamorphic low-sulfide PGE mineralization with widespread Pd and Pt telluro-bismuthides, arsenides, stannides, antimonides, and selenides. The ore formation was accompanied by PGE redistribution and segregation of lenticular orebodies with diffuse contours. Thus, the Monchegorsk ore cluster is characterized by juxtaposition of unaltered primary magmatic deposits and those formed as a result of their metamorphism and distinguished from the former by structure and composition. The comparative study of these deposits opens up new possibilities for comprehending ore-forming processes in the same situations.

  5. The petrology of the layered gabbro intrusion, eastern gabbro, Coldwell alkaline complex, Northwestern Ontario, Canada: evidence for multiple phases of intrusion in a ring dyke

    NASA Astrophysics Data System (ADS)

    Shaw, Cliff S. J.

    1997-07-01

    The Coldwell alkaline complex is a large (> 350 km 2) gabbro and syenite intrusion on the north shore of Lake Superior. It was emplaced at 1108 Ma during early magmatic activity associated with the formation of the Mid-Continent Rift of North America. The eastern gabbro forms a partial ring dyke on the outer margin of the complex and consists of at least three discrete intrusions. The largest of these is the layered gabbro that comprises a 300 m thick fine- to medium-grained basal unit overlain by up to 1100 m of variably massive to layered gabbroic cumulates which vary from olivine gabbro to anorthosite. Several xenoliths of Archaean metamorphic rocks that range in size from 10's to 100's of meters are present in the central part of the intrusion. Within discrete horizons in the layered gabbro are many centimeter- to meter-scale, gabbroic xenoliths. The main cumulus minerals, in order of crystallization, are plagioclase, olivine and clinopyroxene ± Fe-Ti oxides. Biotite and Fe-Ti-oxide are the dominant intercumulus phases. Orthopyroxene occurs not as a cumulus phase but as peritectic overgrowths on cumulus olivine. A detailed petrographic and mineral chemical study of samples from two stratigraphically controlled traverses through the layered gabbro indicates that the stratigraphy cannot be correlated along the 33 km strike of the ring dyke. Mineral compositions show both normal and reversed fractionation trends. These patterns are interpreted to record at least three separate intrusions of magma into restricted dilatant zones within the ring dyke possibly associated with ongoing caldera collapse. Calculations of parental melt composition using mineral — melt equilibria show that even the most primitive gabbros crystallized from an evolved magma with mg# of 0.42-0.49. The presence of orthopyroxene overgrowths on cumulus olivine suggests rising silica activity in the melt during crystallization and implies a subalkaline parentage for the layered gabbro.

  6. 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.

  7. Geochemistry, Petrology, and Provenance of Magnetite-Rich Ortaklar Cu Deposit Hosting Basalts from Koçali Complex, Gaziantep, Turkey

    NASA Astrophysics Data System (ADS)

    Yun, E.; Lee, I.; Kang, J.; Dönmez, C.; Yildirim, N.

    2015-12-01

    Magnetite-rich Cyprus type VMS deposit has been recently discovered from the Ortaklar-Gaziantep region within Koçali complex, SE Turkey. Magnetite rich sulfide ore bodies are in close contact with underlying footwall spilitic basalts. These basalts are part of Koçali mélange, which represents an accreted oceanic complex during closing of southern Neotethys. These extrusives are low-K, low alkali tholeiites with Ca rich, partially sericitized plagioclase subophitically enclosed by augite with disseminated Fe-Ti oxides and pyrite. Mineral crystallization sequence of plagioclase followed by augite and opaque is typical of MORB. Major and trace element analyses for least altered basalts based on LOI (1.5~3.6 wt%), Ce/Ce* (0.9~1.1) exhibit limited range of element abundances. Low Mg# (59~60) suggests that basalts were derived from moderately evolved magma with fractional crystallization. HFSE (Th, Nb, Hf, Zr) were used for tectonic discrimination and basalts were plotted within MORB end spectrum, near MORB-IAT boundary. N-MORB normalized La to Lu ranges from 0.4 to 0.9 times N-MORB with LREE depletion [(La/Sm)N = 0.58~0.67] and flat HREE [(Tb/Lu)N = 0.95~1.05]. Chondrite normalized REE patterns resemble those of N-MORB but characterized by severe LREE depletion [(La/Sm)CN = 0.35~0.45]. LREE depletion coupled with high Sm/Nd (0.36~0.43), high CaO/Na2O (5.0~6.2) and low Nb/Yb (0.23~0.39) suggest depleted N-MORB composition derived from the refractory mantle source. Analyzed basalts are similar to those found from other rift (Costa Rica Rift Hole 504b) and intra-transform fault (Siqueiros transform). Magnetite emplacement occurring close to the ore-host boundary and lack of pyrrhotite from hosting basalts imply an involvement of oxidized hydrothermal fluids. Basalts probably have formed by late stage, partial melting of the refractory mantle at low pressure, shallow depth, and H2O rich environment. Possible source of mantle heterogeneity can be identified by isotope

  8. Petrology and Sm-Nd dating of the Genina Gharbia Alaskan-type complex (Egypt): Insights into deep levels of Neoproterozoic island arcs

    NASA Astrophysics Data System (ADS)

    Helmy, Hassan M.; Abd El-Rahman, Yasser M.; Yoshikawa, Masako; Shibata, Tomoyuki; Arai, Shoji; Tamura, Akihiro; Kagami, Hiroo

    2014-06-01

    The deep levels of Neoproterozoic island arcs are poorly known due to limited accessibility. The Genina Gharbia Alaskan-type complex (south Eastern Desert, Egypt) is the remains of a magma chamber that crystallized at the base (crust-mantle boundary) of a mature Neoproterozoic island arc. The rock assemblage comprises hornblende-bearing harzburgite, lherzolite, pyroxenite, norite and gabbro. All lithologies show cumulus texture with evidence of extensive cumulus mineral-melt interactions. Clinopyroxenes from all lithologies have similar rare earth element (REE) patterns with slight medium-rare earth element (MREE) enrichment. Hornblendes are slightly enriched in MREE and light rare earth elements (LREE). Island arc signatures are indicated by high contents of large ion-lithophile elements and low concentration of high field-strength elements. Positive initial εNd (+ 5.7 to + 7.0) and Nd model ages (963 ± 81 Ma) are consistent with the Genina Gharbia magma being extracted from a depleted mantle source. Modeling of estimated parental magma indicates 10% partial melting of a 90% depleted mantle source with a 10% (MORB + sediments)-derived fluid, commencing in the spinel stability field (< 85 km). Relative to Phanerozoic arcs, the Neoproterozoic arcs were more hydrous, had low oxidation states and probably lasted shorter time to build-up. The hydrous nature of the sub-Arabian-Nubian Shield mantle and the long-life of the arcs are among reasons responsible for the vast crustal growth during the Pan-African Orogeny throughout the Gondwana.

  9. Petrology, geochemistry, and metamorphic evolution of meta-sedimentary rocks in the Diancang Shan-Ailao Shan metamorphic complex, Southeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Liu, Fulai; Liu, Pinghua; Shi, Jianrong; Cai, Jia

    2016-07-01

    Meta-sedimentary rocks are widely distributed within the Diancang Shan-Ailao Shan metamorphic complex in the Southeastern Tibetan Plateau. Detailed geochemical analyses show that all of them have similar geochemical features. They are enriched in light rare-earth elements (LREEs) and depleted in heavy rare-earth elements (HREEs), with moderately negative Eu anomalies (Eu/Eu∗ = 0.55-0.75). Major and trace element compositions for the meta-sedimentary rocks suggest that the protoliths were probably claystone, siltstone, and greywacke and deposited in an active continental margin. Garnet porphyroblasts in meta-sedimentary rocks have distinct compositional zonation from core to rim. The zonation of garnet in St-Ky-Grt-Bt-Ms schist indicates an increasing P-T trend during garnet growth. In contrast, garnets from (Sil)-Grt-Bt paragneiss show diffusion zoning, implying a decreasing P-T trend. Based on mineral transformations and P-T estimates using conventional geothermobarometers and pseudosection calculations, four metamorphic stages have been determined, including an early prograde metamorphic stage (M1), a peak amphibolite-granulite facies metamorphic stage (M2), a near-isothermal decompression stage (M3), and a late amphibolites-facies retrograde stage (M4). The relic assemblage of Ms + St ± Ky ± Bt ± Kfs + Qz preserved as inclusions in garnet porphyroblasts of the meta-sedimentary rocks belongs to prograde (M1) stage and records P-T conditions of 560-590 °C and 5.5-6.3 kb. Matrix mineral assemblages of Grt + Bt + Ky/Sil + Pl + Qz and Grt + Bt ± Sil + Pl ± Kfs + Qz formed at peak (M2) stage yield P-T conditions of 720-760 °C and 8.0-9.3 kb. M3 is characterized by decompression reactions, dehydration melting of assemblages that include hydrous minerals (e.g., biotite), and partial melting of felsic minerals. The retrograde assemblages is Grt + Bt + Sil + Pl + Qz formed at 650-760 °C and 5.0-7.3 kb. At the amphibolites-facies retrograde (M4) stage, fine

  10. A Digital Approach to Learning Petrology

    NASA Astrophysics Data System (ADS)

    Reid, M. R.

    2011-12-01

    In the undergraduate igneous and metamorphic petrology course at Northern Arizona University, we are employing petrographic microscopes equipped with relatively inexpensive ( $200) digital cameras that are linked to pen-tablet computers. The camera-tablet systems can assist student learning in a variety of ways. Images provided by the tablet computers can be used for helping students filter the visually complex specimens they examine. Instructors and students can simultaneously view the same petrographic features captured by the cameras and exchange information about them by pointing to salient features using the tablet pen. These images can become part of a virtual mineral/rock/texture portfolio tailored to individual student's needs. Captured digital illustrations can be annotated with digital ink or computer graphics tools; this activity emulates essential features of more traditional line drawings (visualizing an appropriate feature and selecting a representative image of it, internalizing the feature through studying and annotating it) while minimizing the frustration that many students feel about drawing. In these ways, we aim to help a student progress more efficiently from novice to expert. A number of our petrology laboratory exercises involve use of the camera-tablet systems for collaborative learning. Observational responsibilities are distributed among individual members of teams in order to increase interdependence and accountability, and to encourage efficiency. Annotated digital images are used to share students' findings and arrive at an understanding of an entire rock suite. This interdependence increases the individual's sense of responsibility for their work, and reporting out encourages students to practice use of technical vocabulary and to defend their observations. Pre- and post-course student interest in the camera-tablet systems has been assessed. In a post-course survey, the majority of students reported that, if available, they would use

  11. Petrology and mineralogy of the La Peña igneous complex, Mendoza, Argentina: An alkaline occurrence in the Miocene magmatism of the Southern Central Andes

    NASA Astrophysics Data System (ADS)

    Pagano, Diego Sebastián; Galliski, Miguel Ángel; Márquez-Zavalía, María Florencia; Colombo, Fernando

    2016-04-01

    The La Peña alkaline igneous complex (LPC) is located in the Precordillera (32°41‧34″ S - 68°59‧48″ W) of Mendoza province, Argentina, above the southern boundary of the present-day flat-slab segment. It is a 19 km2 and 5 km diameter subcircular massif emplaced during the Miocene (19 Ma) in the Silurian-Devonian Villavicencio Fm. The LPC is composed of several plutonic and subvolcanic intrusions represented by: a cumulate of clinopyroxenite intruded by mafic dikes and pegmatitic gabbroic dikes, isolated bodies of malignite, a central intrusive syenite that develops a wide magmatic breccia in the contact with clinopyroxenite, syenitic and trachytic porphyries, a system of radial and ring dikes of different compositions (trachyte, syenite, phonolite, alkaline lamprophyre, tephrite), and late mafic breccias. The main minerals that form the LPC, ordered according to their abundance, are: pyroxene (diopside, hedenbergite), calcium amphibole (pargasite, ferro-pargasite, potassic-ferro-pargasite, potassic-hastingsite, magnesio-hastingsite, hastingsite, potassic-ferro-ferri-sadanagaite), trioctahedral micas (annite-phlogopite series), plagioclase (bytownite to oligoclase), K-feldspar (sanidine and orthoclase), nepheline, sodalite, apatite group minerals (fluorapatite, hydroxylapatite), andradite, titanite, magnetite, spinel, ilmenite, and several Cu-Fe sulfides. Late hydrothermal minerals are represented by zeolites (scolecite, thomsonite-Ca), epidote, calcite and chlorite. The trace element patterns, coupled with published data on Sr-Nd-Pb isotopes, suggest that the primary magma of the LPC was generated in an initially depleted but later enriched lithospheric mantle formed mainly by a metasomatized spinel lherzolite, and that this magmatism has a subduction-related signature. The trace elements pattern of these alkaline rocks is similar to other Miocene calc-alkaline occurrences from the magmatic arc of the Southern Central Andes. Mineral and whole

  12. The Genesis of SESAPS

    NASA Astrophysics Data System (ADS)

    Mickens, Ronald

    2008-04-01

    On March 23, 1935, a meeting of ``Southern Physicist" was held at the Candler Hotel in Decatur, Georgia. In addition to a scientific program the next day, consisting of the presentation of twenty-five papers (held in the Emory University's chemistry building), an address was given by Professor A. H. Compton on that Friday night during a banquet sponsored by the Georgia Academy of Science. However, the main goal of this meeting was to work out the details of a new organization, which was called the ``Southern Association of Physicists." My talk provides background on the genesis of this gathering and gives a brief summary of the new organization's subsequent activities, including its ``absorption" by the American Physical Society as its Southeastern Section, i.e., SESAPS. In particular, I discuss its management structure; its three awards for teaching, research, and leadership; and the planning process for its annual meeting. My general conclusion is that SESAPS has been very successful in promoting ``physics" in the southeastern states.

  13. Using quantitative phase petrology to understand metamorphism

    NASA Astrophysics Data System (ADS)

    White, Richard

    2015-04-01

    Quantitative phase petrology has become one of the mainstay methods for interpreting metamorphic rocks and processes. Its increased utility has been driven by improvements to end-member thermodynamics, activity-composition relationships and computer programs to undertake calculations. Such improvements now allow us to undertake calculations in increasingly complex chemical systems that more closely reflect those of rocks. Recent progress in activity-composition (a-x) relationships is aimed at developing suites of a-x relationships in large chemical systems that are calibrated together, which will allow a more direct application of the method to metamorphic rocks. In addition, considerable progress has been made in how quantitative phase diagrams can be used to understand features, including chemical potential diagrams for reaction textures, methods for fractionating bulk compositions and methods for modelling open system processes. One feature of calculated phase diagrams is that they present us with a great amount of information, such as mineral assemblages, mineral proportions, phase compositions, volume or density etc. An important aspect to using this information is to understand the potential uncertainties associated with these, which are significant. These uncertainties require that calculated phase diagrams be used with caution to interpret observed features in rocks. Features such as mineral zoning and reaction textures should still be interpreted in a semi-quantitative way, even if based on a fully quantitative diagram. Exercises such as the interpretation of reaction overstepping based on relating phase diagrams to observed mineral core compositions are likely to give spurious results given the infelicities in existing a-x models. Despite these limitations, quantitative phase petrology remains the most useful approach to interpreting the metamorphic history of rocks in that it provides a theoretical framework in which to interpret observed features rather

  14. Lunar breccias, petrology, and earth planetary structure

    NASA Technical Reports Server (NTRS)

    Ridley, W. I.

    1978-01-01

    Topics covered include: (1) petrologic studies of poikiloblastic textured rocks; (2) petrology of aluminous mare basalts in breccia 14063; (3) petrology of Apollo 15 breccia 15459; (4) high-alumina mare basalts; (5) some petrological aspects of imbrium stratigraphy; (6) petrology of lunar rocks and implication to lunar evolution; (7) the crystallization trends of spinels in Tertiary basalts from Rhum and Muck and their petrogenetic significance; (8) the geology and evolution of the Cayman Trench; (9) The petrochemistry of igneous rocks from the Cayman Trench and the Captains Bay Pluton, Unalaska Island and their relation to tectonic processes at plate margins; and (10) the oxide and silicate mineral chemistry of a Kimberlite from the Premier Mine with implications for the evolution of kimberlitic magma.

  15. 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.

  16. The Flare Genesis Experiment

    NASA Technical Reports Server (NTRS)

    Rust, D. M.

    2002-01-01

    Using the Flare Genesis Experiment (FGE), a balloon-borne observatory with an 80-cm solar telescope we observed the active region NOAA 8844 on January 25, 2000 for several hours. FGE was equipped with a vector polarimeter and a tunable Fabry-Perot narrow-band filter. It recorded time series of filtergrams, vector magnetograms, and Dopplergrams at the Ca(I) 6122.2 angstrom line, and H-alpha filtergrams with a cadence between 2.5 and 7.5 minutes. At the time of the observations, NOAA 8844 was located at approximately 5 N 30 W. The region was rapidly growing during the observations; new magnetic flux was constantly emerging in three supergranules near its center. We describe in detail how the FGE data were analyzed and report on the structure and behavior of peculiar moving dipolar features (MDFs) observed in the active region. In longitudinal magnetograms, the MDFs appeared to be small dipoles in the emerging fields. The east-west orientation of their polarities was opposite that of the sunspots. The dipoles were oriented parallel to their direction of motion, which was in most cases towards the sunspots. Previously, dipolar moving magnetic features have only been observed flowing out from sunspots. Vector magnetograms show that the magnetic field of each MDF negative part was less inclined to the local horizontal than the ones of the positive part. We identify the MDFs as undulations, or stitches, where the emerging flux ropes are still tied to the photosphere. We present a U-loop model that can account for their unusual structure and behavior, and it shows how emerging flux can shed its entrained mass.

  17. Petrogenesis of the Late Cretaceous Demirköy Igneous Complex in the NW Turkey: Implications for magma genesis in the Strandja Zone

    NASA Astrophysics Data System (ADS)

    Karacık, Zekiye; Tüysüz, Okan

    2010-02-01

    The Srednogorie Zone in Bulgaria and its eastern continuation in NW Turkey, the Strandja Zone, consist of a Late Cretaceous magmatic belt comprised of plutonic, volcanic and associated volcano-sedimentary rocks. The Demirköy Igneous Complex is the biggest Cretaceous pluton within the Strandja Zone, and its age is between 71 and 84 Ma. The Demirköy pluton and additional smaller plutons are intruded into Triassic and older metamorphic basement rocks. A contact metamorphic aureole with hornblende-hornfels facies conditions was developed around the Demirköy pluton. The WNW-trending Demirköy pluton has an elliptical shape and a concentrically zoned internal structure. In this structure, gabbro/diorites and quartz diorites are only seen in the SW corner of the pluton, while granodiorites form the main body of the pluton surrounded by a zone of granite. The granodiorites contain dioritic mafic microgranular enclaves. Small quartz monzonite lenses and/or bodies and mafic dykes are also observed in the Demirköy Igneous Complex. Geochemically, the Demirköy Igneous Complex has calc-alkaline, metaluminous and medium-K characteristics. There is a significant correlation between the LREE/HREE ratios and SiO 2 values. Chondrite-normalized REE patterns are relatively flat (La N/Lu N = 2) in gabbros. This ratio ranges from 3 to 11 for the diorite/granodiorites, and from 14 to 35 for the granites. Dioritic enclaves have REE patterns similar to those of the main body and have La N/Lu N values between 3 and 6. Relatively enriched LILE (Sr, K, Rb, Ba and Th) and relatively depleted HFSE (Ta, Nb and Ti) values indicate the classic subduction-related origin of the complex. The initial isotopic signatures range from ɛNd( i) = - 0.45 to - 2.57 and 87Sr/ 86Sr( i) = 0.7042-0.7064 for gabbros and ɛNd( i) = - 0.43 to - 2.67 and 87Sr/ 86Sr( i) = 0.7048-0.7059 for granodiorites and granites. δ18O values range from + 6.18 to + 7.80‰ (VSMOW) for gabbros and from + 6.86 to + 8.89

  18. Eaton AF5000+Genesis Communication Driver

    Energy Science and Technology Software Center (ESTSC)

    1995-05-25

    Communication driver allows the Genesis Control Series software to interact with Eaton AF5000+ frequency drives via RS-232 communications. All Eaton AF5000+ parameters that support communications are supported by the Genesis driver. Multidrop addressing to multiple units is available with the Genesis communication driver.

  19. The Role of Fractional Crystallization and Magma Mixing/Mingling in the Genesis of Karacaali Magmatic Complex (Central Anatolia, Turkey) Fe, Mo-Cu Mineralizations

    NASA Astrophysics Data System (ADS)

    Delibas, O.; Genc, Y.; de Campos, C. P.

    2009-05-01

    This work brings into focus different metal associations (Fe and Mo-Cu) characteristic for the Karacaali Magmatic Complex (KMC), in Central Anatolia, Turkey. The Mo-Cu mineralization is widespread hosted in rhyolitic-rhyodacitic/granidoid rocks or is related to N-S striking vertical quartz-calcite veins. The Fe mineralization, on the other hand, is hosted in gabbroic/basaltic rocks. Field relations and geochronologic studies on single zircons (U-Pb) point towards a coeval temporal relation between plutonites and volcanites. The relatively overlapping ages between monzonite (73.1 Ma) and rhyolitic rocks (67 Ma) reflect a long lasting gradual crystallization within a zoned magma chamber. This is confirmed by progressive transitional contacts from plutonites into volcanites. Based on detailed field, textural and petrographic studies, granitic and monzonitic rocks have been subdivided into four different facies. These are: porphyritic quartz monzonites, quartz-monzonites, fine-grained granites and porphyritic leucogranites. Furthermore, highly diverse textures and structures, which are typical for hybrid rocks, reveal important magma mixing/migling and fractional crystalization processes. From additional geochemical studies, granitic rocks show high Rb/Sr (1.52), nearly flat REE patterns and strong Eu negative anomalies. However; monzonitic and hybrid rocks have relatively low Rb/Sr ratios (0.37 and 0.32) and depleted HREE patterns. Thus, in this complex, granitic rocks are considered as evolved products from the felsic magma. Strong positive Mo-correlation within the granitoids can be explained by a high degree of magmatic fractionation (Ishihara and Tani, 2004). Therefore, last evolved granitic melts are enriched in Mo- rich volatiles giving rise to molybdenite-quartz-calcite veins. Field, macro-micro and chemical studies evidence a co-magmatic origin for the gabbroic/basaltic-hosted Fe-mineralization. Despite the very close relation between compositional character

  20. Petrology of Anomalous Eucrite QUE 94484

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    Most mafic achondrites are broadly "eucritic", being composed of ferroan low-Ca clinopyroxene, high-Ca plagioclase, a silica phase, ilmenite and accessory phases. Their characteristics indicate that eucrite-like basalts formed on asteroids of similar composition under similar petrologic conditions (T, P, fO2). Some eucrite-like basalts have isotopic compositions and petrologic characteristics consistent with formation on different parent asteroids (e.g., Ibitira, NWA 011). Others show small isotopic differences but no distinguishing petrological characteristics (e.g., Caldera, Pasamonte). We have begun a study of anomalous eucrite-like achondrites in an effort to seek resolution to the issues: Did the eucrite parent asteroid fail to homogenize via a magma-ocean stage, thus explaining outliers like Pasamonte? How many parent asteroids are represented by these basalts? Here we present preliminary petrologic information on anomalous basaltic eucrite QUE 94484.

  1. Multiple sulfur isotope and mineralogical constraints on the genesis of Ni-Cu-PGE magmatic sulfide mineralization of the Monchegorsk Igneous Complex, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Bekker, A.; Grokhovskaya, T. L.; Hiebert, R.; Sharkov, E. V.; Bui, T. H.; Stadnek, K. R.; Chashchin, V. V.; Wing, B. A.

    2015-08-01

    We present the results of a pilot investigation of multiple sulfur isotopes for the Ni-Cu-PGE sulfide mineralization of the ˜2.5 Ga Monchegorsk Igneous Complex (MIC). Base Metal Sulfide (BMS) compositions, Platinum Group Element (PGE) distributions, and Platinum Group Mineral (PGM) assemblages were also studied for different types of Ni-Cu-PGE mineralization. The uniformly low S content of the country rocks for the MIC as well as variable Sm-Nd isotope systematics and low-sulfide, PGE-rich mineralization of the MIC suggest that S saturation was reached via assimilation of silicates rather than assimilation of sulfur-rich lithologies. R-factor modeling suggests that the mixing ratio for silicate-to-sulfide melt was very high, well above 15,000 for the majority of our mineralized samples, as might be expected for the low-sulfide, PGE-rich mineralization of the MIC. Small, negative Δ33S values (from -0.23 to -0.04 ‰) for sulfides in strongly metamorphosed MIC-host rocks indicate that their sulfur underwent mass-independent sulfur isotope fractionation (MIF) in the oxygen-poor Archean atmosphere before it was incorporated into the protoliths of the host paragneisses and homogenized during metamorphism. Ore minerals from the MIC have similar Δ33S values (from -0.21 to -0.06 ‰) consistent with country rock assimilation contributing to sulfide saturation, but, also importantly, our dataset suggests that Δ33S values decrease from the center to the margin of the MIC as well as from early to late magmatic phases, potentially indicating that both local assimilation of host rocks and S homogenization in the central part of the large intrusion took place.

  2. Regional seismic reflection line, southern Illinois Basin, provides new data on Cambrian rift geometry, Hicks Dome genesis, and the Fluorspar Area Fault Complex

    SciTech Connect

    Potter, C.J.; Goldhaber, M.B.; Taylor, C.D. ); Heigold, P.C. )

    1992-01-01

    Detailed studies of the subsurface structure of the Cambrian Reelfoot rift (RFR) in the Midwestern US provide important insights into continental rifting processes and into the structural fabric of a zone of modern intracratonic seismicity (New Madrid zone). High-quality oil industry seismic reflection data show that in the area of transition between the RFR and the Rough Creek Graben (RCG) the geometry of the Cambrian rift system is that of a half-graben that thickens to the southeast. This contrasts with the northward-thickening half-graben observed to the east in the RCG and with the more symmetric graben to the south in the RFR. An 82.8-km segment of a northwest-southeast seismic reflection profile in southeastern Illinois and western Kentucky shows that near Hicks Dome, Illinois, Middle and Lower Cambrian syn-rift sedimentary rocks occupy about 0.35 s (two-way travel time) on the seismic reflection section (corresponding to a thickness of about 970 m). This stratigraphic interval occupies about 0.45 s (1,250 m) near the Ohio river and is thickest against the Tabb Fault System (TFS) in Kentucky, where it occupies 0.7 s (1,940 m). The seismic data show that in this part of the Cambrian rift the master fault was part of the TFS and that normal displacement on the TFS continued through middle Paleozoic time. The seismic data also provide new information on the late Paleozoic development of Hicks-Dome and the surrounding Fluorspar Area Fault Complex (FAFC) in southeastern Illinois and western Kentucky. A series of grabens and horsts in the FAFC document a late Paleozoic reactivation of the RFR. Comparison of the reflection data with surface mineralization patterns shows that in most cases mineralized graben-bounding faults clearly cut basement or are splays from faults that cut basement.

  3. The geochemistry of primitive volcanic rocks of the Ankaratra volcanic complex, and source enrichment processes in the genesis of the Cenozoic magmatism in Madagascar

    NASA Astrophysics Data System (ADS)

    Melluso, L.; Cucciniello, C.; le Roex, A. P.; Morra, V.

    2016-07-01

    The Ankaratra volcanic complex in central Madagascar consists of lava flows, domes, scoria cones, tuff rings and maars of Cenozoic age that are scattered over 3800 km2. The mafic rocks include olivine-leucite-nephelinites, basanites, alkali basalts and hawaiites, and tholeiitic basalts. Primitive samples have high Mg# (>60), high Cr and Ni concentrations; their mantle-normalized patterns peak at Nb and Ba, have troughs at K, and smoothly decrease towards the least incompatible elements. The Ankaratra mafic rocks show small variation in Sr-Nd-Pb isotopic compositions (e.g., 87Sr/86Sr = 0.70377-0.70446, 143Nd/144Nd = 0.51273-0.51280, 206Pb/204Pb = 18.25-18.87). These isotopic values differ markedly from those of Cenozoic mafic lavas of northern Madagascar and the Comoro archipelago, typical Indian Ocean MORB and oceanic basalt end-members. The patterns of olivine nephelinitic magmas can be obtained through 3-10% partial melting of a mantle source that was enriched by a Ca-rich alkaline melt, and that contained garnet, carbonates and phlogopite. The patterns of tholeiitic basalts can be obtained after 10-12% partial melting of a source enriched with lower amounts of the same alkaline melt, in the spinel- (and possibly amphibole-) facies mantle, hence in volumes where carbonate is not a factor. The significant isotopic change from the northernmost volcanic rocks of Madagascar and those in the central part of the island implicates a distinct source heterogeneity, and ultimately assess the role of the continental lithospheric mantle as source region. The source of at least some volcanic rocks of the still active Comoro archipelago may have suffered the same time-integrated geochemical and isotopic evolution as that of the northern Madagascar volcanic rocks.

  4. Genesis and Characteristics of Debris Flow Ocurred in 2013 in the Atenquique Ravine, Located on the Eastern Slope of the Colima Volcanic Complex, Mexico.

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Flores-Pena, S.; Nunez-Cornu, F. J.; Arreola-Ochoa, L. C.; Suarez-Gonzalez, B. V.

    2014-12-01

    Hurricane Manuel affected the Pacific coast of Mexico on September 15 and 16, 2013 causing heavy rainfall of about 240 mm in a 24 hour period in the area of the Volcanic Complex (VC). Heavy rainfall led to the beginning of a significant flow of mud and rocks draining from the Atenquique Creek, located on the eastern slope of the VC in a west east direction. The result of this flow was the heavy damage sustained by the local paper plant located next to the town of Atenquique in the distal part of the basin where the stream is gathered by the Tuxpan River. Damages totaling over 15 million dollars affected a large part in their recycled fibers factory, resulting in an 18-month full stoppage of the factory. This in turn caused a heavy setback of the economy located within a large region of the southern state of Jalisco. Once again on November 25, debris flow occurred only at a lower volume than the September rains, without causing any damage. Both flows contained a viscous and solid liquid flow that left deposits of silt-sandy clasts and other abundant materials of reverse gradation. The first flow reached a thickness of 4.5 m in the Tuxpan riverbed over a length of about 15 km, while the November flow left behind 1.3 m of fine materials and few clasts. The Atenquique ravine historically has had debris flow caused by heavy rainfall from hurricanes. On October 1955 debris flow claimed many deaths and heavy damage to the town and local paper mill. These flows are generated in the summer and they are associated to several factors such as weather, steep slopes, unstable volcanic strata, these elements add an important environmental history in the area, as is the use of continuous deforestation. The current land use has resulted in a positive change from forest to intensive agriculture; but having constant wildfires on the high slopes of the VC and the combination of many other factors such as changes on the soil of the slopes and movement of geological material "scarps and

  5. Carbon petrology in cometary dust

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1992-01-01

    Chondritic porous (CP) interplanetary dust particles (IDP's) are collected in the Earth's stratosphere. There exists an extensive database on major and minor element chemistry, stable isotopes, noble gas abundances and mineralogy of many CP IDP's, as well as infrared and Raman spectroscopic properties. For details on the mineralogy, chemistry and physical properties of IDP's, I refer to the reviews by Mackinnon and Rietmeijer (1987), Bradley et al. (1988) and Sandford (1987). Texture, mineralogy (Mackinnon and Rietmeijer, 1987) and chemistry (Schramm et al., 1989; Flynn and Sutton, 1991) support the notion that CP IDP's are a unique group of ultrafine-grained extraterrestiral materials that are distinct from any known meteorite class. Their fluffy, or porous, morphology suggests that CP IDP's probably endured minimal alteration by protoplanetary processes since their formation. It is generally accepted that CP IDP's are solid debris from short-period comets. The evidence is mostly circumstantial but this notion gained significant support based on the comet Halley dust data (Brownlee, 1990). In this paper, I will accept that CP IDP's are indeed cometary dust. The C/Si ratio in CP IDP's is 3.3 times higher than in CI carbonaceous chondrites (Schramm et al. 1989). The intraparticle carbon distribution is heteorogeneous (Rietmeijer and McKay, 1986). Carbon occurs both in oxidized and reduced forms. Analytical electron microscope (AEM) and Raman spectroscopic analyses have shown the presence of several carbon forms in CP IDP's but the data are scattered in the literature. Carbons in cometary CP IDP's are among the most pristine Solar System carbons available for laboratory study. Similar to a recently developed petrological model for the diversity of layer silicates in CP IDP's (Zolensky, 1991) that is useful to constrain in situ aqueous alteration in comets (Rietmeijer and Mackinnon, 1987a), I here present the first effort to develop a petrological concept of carbons

  6. Genesis Preliminary Examination: Ellipsometry Overview

    NASA Technical Reports Server (NTRS)

    Stansbery, E. K.; McNamara, K. M.

    2005-01-01

    The Genesis spacecraft returned to Earth on September 8, 2004, experiencing a non-nominal reentry in which both the drogue and main parachutes failed to deploy causing the capsule to impact the surface of the UTTR desert at a speed of approximately 310 kph (193 mph). The impact caused severe damage to the capsule and a breach of the science canister in the field. The science canister was recovered and transported to the cleanroom at UTTR within approximately 8 hours of reentry. Although the ground water table did not rise to canister level before removal, damp soil and debris from the heat shield and other spacecraft components did enter the canister and contaminate some collector surfaces. The objective of preliminary examination of the Genesis collectors is to provide the science community with the information necessary to request the most useful samples for their analysis.

  7. Reconstruction of the Genesis Entry

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Qualls, Garry D.; Schoenenberger, Mark

    2005-01-01

    This paper provides an overview of the findings from a reconstruction analysis of the Genesis capsule entry. First, a comparison of the atmospheric properties (density and winds) encountered during the entry to the pre-entry profile is presented. The analysis that was performed on the video footage (obtained from the tracking stations at UTTR) during the descent is then described from which the Mach number at the onset of the capsule tumble was estimated following the failure of the drogue parachute deployment. Next, an assessment of the Genesis capsule aerodynamics that was extracted from the video footage is discussed, followed by a description of the capsule hypersonic attitude that must have occurred during the entry based on examination of the recovered capsule heatshield. Lastly, the entry trajectory reconstruction that was performed is presented.

  8. Petrology and structural modeling of skarn genesis in the Tange-Hana area (SW Iran)

    NASA Astrophysics Data System (ADS)

    Moradipoor, Mahshid; Samani, Babak

    2010-05-01

    Tang-e-Hana region is located in the Snandaj-Sirjan structural zone in the Northwestern of Neyriz in the East of Fars province. The area mainly consist of ultramafic (harzburgite, dunite, wehrlite), mafic (gabbro) and marble rocks which partly changed to skarn. Contact of ultramafic rocks and Cretaceous calcite unites cause to form marble and skarn rocks in the study area. The main minerals in skarns are garnet (andradite+grossular), clinopyroxene (diopside, hedenbergite) Vesuvianite, Scapolite, wollastonite and magnetite. The skarn rocks show different temporal compound, so that the formation of wollastonite and garnet show gradual increase and decrease from SE to NW of the study area. The existence of wollastonite in the skarns of northern part of Tang-e-Hana is due to high temperature gradient and Xco2. According to microprobe analysis and field studies the temperature and Xco2 of the skarn rocks at the time of generation was estimated between 600˚-800˚ and 0.03-0.3. Also the effective pressure of Oxygen was changed between 10-12 to 10-28 . In this paper we try to explain the changes of mention parameters with application of structural evolution models.

  9. Petrologic implications of plate tectonics.

    PubMed

    Yoder, H S

    1971-07-30

    Petrologists can make significant contributions to the plate tectonic concept. Fixing the stability fields of the principal rock types involved will provide the limits of pressure and temperature of the various environments. Experimental determination of the partition coefficients of the trace elements will be helpful. Studies of the partial melting behavior of possible parental materials in the absence and presence of water, especially the undersaturated region, will contribute to the understanding of magma production. Experimental observations on the rheological properties of the peridotites below and just above the solidus will lead to a better evaluation of the convective mechanism. Measurement of the fundamental properties of rocks, such as the density of solids and liquids at high pressures and temperatures, would contribute to understanding the concepts of diapiric rise, magma segregation, and the low-velocity zone. Broader rock sampling of the oceanic areas of all environments will do much to define the petrologic provinces. The field petrologist specializing in the Paleozoic regions and Precambrian shields can contribute by examining those regions for old plate boundaries and devising new criteria for their recognition. PMID:17770454

  10. Petrology, geochemistry, and fluid regime of tectonites

    NASA Astrophysics Data System (ADS)

    Letnikov, Feliks Artem'evich; Savel'Eva, Valentina Borisovna; Balyshev, Sergei Olegovich

    The book discusses the petrology, geochemisry, and fluid regime of the tectonite formation in rocks that differ with respect to the composition of their granulitic, amphylitic, and green-shale metamorphic facies. Tectonites in magma and metamorphic rocks of different composition are described in terms of their petrological, geochemical, and fluid-regime characteristics, and the pressure/temperature conditions of their formation. Using chemical and physical parameters, tectonites are classified according to their type models. The ore-generating capacity of tectonites in various rocks is estimated using a large geochemical database.

  11. Fluorescence spectroscopy: A promising tool for carbonate petrology

    SciTech Connect

    Vice, M.A.; Bensley, D.F.; Utgaard, J.E. . Dept. of Geology)

    1992-01-01

    Responses of depositional and diagenetic components in samples of the Mission Canyon Limestone to blue-light excitation vary most noticeably with mineralogy and crystal size. The finely crystalline micrites, dolomicrites and argillaceous carbonates fluoresce more intensely than the more coarsely crystalline sparry calcite cements, dolospar cements and coarsely crystalline dolomites. Low intensity spectral analysis of cherts, anhydrites, and the carbonate phases provides an objective manner for quantifying fluorescence responses and for comparing them statistically. Nineteen of the optical parameters used in organic petrology are evaluated for their utility in carbonate petrology. Results of the discriminant function analysis suggest that red-weighted fluorescence chromaticity indices and yellow-weighted ones are more useful for mineral identification than the blue-weighted or equal-energy chromaticity indices. Statistical analysis of the optical data, mineralogy, and minor element compositions suggests correlations between the fluorescence responses and major minerals, carbonate diagenetic components, and the minor element geochemistry of carbonate components. Although no single element is identified as an activator of fluorescence in this study, the complex correlations of optical indices with Fe suggest that it does act to quench fluorescence. The four fluorescence cy chromaticity indices correlate significantly and positively with mineralogy and negatively with MgCo[sub 3]. In organic petrology, these indices are related to maceral content. The positive correlations of the four fluorescence cx chromaticity indices with Fe and Mn likely reflect fluorescence response to changes in compositions of pore fluids during diagenesis. This trend parallels the increase in cx indices with increasing maturation of organic materials.

  12. Art, Education, and Community: Arts Genesis, Inc.

    ERIC Educational Resources Information Center

    Kestler, Carol S.

    Arts Genesis, Inc. (AGI) forms partnerships with diverse communities to assist them in finding fulfillment through the arts by meeting their own self-defined needs; uses arts experiences to encourage discovery, creativity, and diversity; and continually strives for excellence in the arts and education. Arts Genesis grew out of "Project…

  13. [The genesis of crime according to dialectic criminology. II. Comments on the genesis of crime].

    PubMed

    Lyra, R; Ferracuti, F

    1978-01-01

    Prof. Lyra discusses in this article the basic problem of criminological sciences, stating that its essential object of study is the determination of the genesis of crime. The Author states that, before defining the crime genesis, it is necessary to outline, through a synthesis of epistemological restructurization of criminology itself. This way, we can develop a conception of Dialectic Criminology, where the term "dialectic" does not necessarily coincide with a marxist posture, but it extends along much more complex and comprehensive parameters. Dialectic Criminology is defined, in Lyra's conception, as a Classified Criminology, synthetizing both the psychological approach (clinical criminology, or micro-criminology), and the sociological approach (sociological criminology or macro-criminology), according to an anthropological basic frame of reference, which constitutes the new and original prerequisite. To this aim, according to Prof. Lyra, it is necessary to overcome merely biological or psychological theories, and the new sociologisms, which cannot explain deviant behavior without falling into dogmatism or relativism. It is necessary to give back to criminology its original ethico-philosophical roots, and to place the problem of crime within a new "praxis" concept, which takes into account the authentic freedom of man, interracting with historical evolution. This way, through Dialectic Criminology, we can overcome the conception of crime and delinquency viewed as counterparts of the concept of Law. PMID:756568

  14. Petrologic Characteristics of the Lunar Surface

    PubMed Central

    Wang, Xianmin; Pedrycz, Witold

    2015-01-01

    Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and focusing on four long-debated and important issues related to lunar formation and evolution, we draw the following conclusions from the new insights into the global distribution of the five petrologic units: (1) there may be no petrogenetic relationship between MS rocks and KB; (2) there may be no petrogenetic link between MS and AS rocks; (3) the exposure of the KREEP component on the lunar surface is likely not a result of MB volcanism but is instead mainly associated with the combined action of plutonic intrusion, KREEP volcanism and celestial collision; (4) the impact size of the South Pole-Aitken basin is constrained, i.e., the basin has been excavated through the whole crust to exhume a vast majority of lower-crustal material and a very limited mantle components to the lunar surface. PMID:26611148

  15. Petrologic Characteristics of the Lunar Surface

    NASA Astrophysics Data System (ADS)

    Wang, Xianmin; Pedrycz, Witold

    2015-11-01

    Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and focusing on four long-debated and important issues related to lunar formation and evolution, we draw the following conclusions from the new insights into the global distribution of the five petrologic units: (1) there may be no petrogenetic relationship between MS rocks and KB; (2) there may be no petrogenetic link between MS and AS rocks; (3) the exposure of the KREEP component on the lunar surface is likely not a result of MB volcanism but is instead mainly associated with the combined action of plutonic intrusion, KREEP volcanism and celestial collision; (4) the impact size of the South Pole-Aitken basin is constrained, i.e., the basin has been excavated through the whole crust to exhume a vast majority of lower-crustal material and a very limited mantle components to the lunar surface.

  16. Petrologic Characteristics of the Lunar Surface.

    PubMed

    Wang, Xianmin; Pedrycz, Witold

    2015-01-01

    Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and focusing on four long-debated and important issues related to lunar formation and evolution, we draw the following conclusions from the new insights into the global distribution of the five petrologic units: (1) there may be no petrogenetic relationship between MS rocks and KB; (2) there may be no petrogenetic link between MS and AS rocks; (3) the exposure of the KREEP component on the lunar surface is likely not a result of MB volcanism but is instead mainly associated with the combined action of plutonic intrusion, KREEP volcanism and celestial collision; (4) the impact size of the South Pole-Aitken basin is constrained, i.e., the basin has been excavated through the whole crust to exhume a vast majority of lower-crustal material and a very limited mantle components to the lunar surface. PMID:26611148

  17. Petrological cycles and caldera-forming events

    NASA Astrophysics Data System (ADS)

    Bachmann, O.; Deering, C. D.

    2012-12-01

    Many caldera-forming events can be framed within broad petrological cycles; volcanic stratigraphy typically defines a trend from mafic to more silicic magmas with time, culminating in the catastrophic evacuation of an upper crustal reservoir filled with the silicic magma, followed by a return to the eruption of more mafic magmas shortly after caldera collapse. Understanding how such cycles develop has clear implications for characterizing the current state of an active system. Here, we focus on a detailed examination of the well-exposed Quaternary Kos-Nisyros eruptive sequence (eastern Aegean arc) to frame a potential model for such cycles. On the basis of zircon U/Th/Pb ages, building the upper crustal magma chamber large enough to induce caldera collapse required at least a few hundred thousand years. This timeframe is necessary not only for the accumulation of large amounts of viscous, gas-rich silicic magma, but also to heat the upper crust sufficiently to allow the developing reservoir to be maintained above the solidus. In the Kos-Nisyros volcanic center, small eruptions precede the caldera-forming event and mark this period of thermal maturation as the system transitions from intermediate to silicic magma, reaching the most-evolved state only shortly prior to the caldera-forming event, the Kos Plateau Tuff (> 60 km3 of volatile-rich, high-silica rhyolite). The Kos Plateau Tuff was then followed by small-volume eruptions of more mafic magma (basaltic andesite, andesite, and dacites) that are characterized by a drier mineral assemblage. With time, the system transitioned back to cold, wet, high-SiO2 rhyolite. We suggest that the changes in magma composition and mineralogy following the caldera-forming event are due to a near-complete crystallization of the non-erupted mush in the upper crustal reservoir as it is abruptly decompressed during eruption. This rapid crystallization (1) leads to the formation of a porphyritic texture in the crystalline residual - a

  18. The Genesis of the Institute

    NASA Astrophysics Data System (ADS)

    Hansford, R. F.

    The Institute of Navigation was born on 12 March 1947 in the Boardroom of Lloyds Register of Shipping. More will be said of this later, but the birth is well documented and defined.It will surprise no one that the conception is much less easily defined, but it is certainly no less significant a part of the genesis of the Institute. This article is an attempt to outline the early history of the Institute.During 1944 and 1945 an Institute of Navigation was formed in the United States and, in May 1945, it held its first Annual General Meeting with Professor Sam Herrick as its Executive Secretary. Its meetings were attended by the Navigation Specialist on the British Air Commission in Washington (Squadron Leader D. O. Fraser) and duly reported back, through the Commission, to the Air Ministry in the United Kingdom.

  19. Genesis: Sorting Out the Pieces

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Westphal, Andrew; Butterworth, A. L.; Burnett, D. S.

    2005-01-01

    The Genesis mission returned to Earth on September 8, 2004, experiencing a non-nominal reentry. The parachutes which were supposed to slow and stabilize the capsule throughout the return failed to deploy, causing the capsule to impact the desert floor at a speed of nearly 200 MPH. The result is that instead of receiving 301 intact solar wind collectors, mission personnel recovered and documented more than 10,000 collector fragments. Most of the fragments were pieces of the collector arrays but were not recovered on their original array locations. These were classified by size (longest dimension), identity (sometimes a guess) and found location (when known). The work took more than one month in Utah, and details are discussed elsewhere[1] The samples were transferred to their permanent home at the Johnson Space Center on October 4, 2004.

  20. Solar composition from the Genesis Discovery Mission.

    PubMed

    Burnett, D S; Team, Genesis Science

    2011-11-29

    Science results from the Genesis Mission illustrate the major advantages of sample return missions. (i) Important results not otherwise obtainable except by analysis in terrestrial laboratories: the isotopic compositions of O, N, and noble gases differ in the Sun from other inner solar system objects. The N isotopic composition is the same as that of Jupiter. Genesis has resolved discrepancies in the noble gas data from solar wind implanted in lunar soils. (ii) The most advanced analytical instruments have been applied to Genesis samples, including some developed specifically for the mission. (iii) The N isotope result has been replicated with four different instruments. PMID:21555545

  1. Solar composition from the Genesis Discovery Mission

    PubMed Central

    Burnett, D. S.; Team, Genesis Science

    2011-01-01

    Science results from the Genesis Mission illustrate the major advantages of sample return missions. (i) Important results not otherwise obtainable except by analysis in terrestrial laboratories: the isotopic compositions of O, N, and noble gases differ in the Sun from other inner solar system objects. The N isotopic composition is the same as that of Jupiter. Genesis has resolved discrepancies in the noble gas data from solar wind implanted in lunar soils. (ii) The most advanced analytical instruments have been applied to Genesis samples, including some developed specifically for the mission. (iii) The N isotope result has been replicated with four different instruments. PMID:21555545

  2. Petrological Mapping of the Crater Boguslawsky

    NASA Astrophysics Data System (ADS)

    Wöhler, C.; Evdokimova, N. A.; Feoktistova, E. A.; Grumpe, A.; Kapoor, K.; Berezhnoy, A. A.; Shevchenko, V. V.

    2015-10-01

    An analysis of orbital spectral data of the crater Boguslawsky, the intended target region of the Russian Luna-Glob mission, is performed. We have constructed a high- resolution DEM of the crater Boguslawsky, based on which the temperature regime on the surface is investigated. The depth of the OH absorption feature is analysed.The content of the main elements is estimated, and a petrologic map is constructed accordingly.

  3. Genesis Halo Orbit Station Keeping Design

    NASA Technical Reports Server (NTRS)

    Lo, M.; Williams, K.; Wilson, R.; Howell, K.; Barden, B.

    2000-01-01

    As the fifth mission of NASA's Directory Program, Genesis is designed to collect solar wind samples for approximately two years in a halo orbit near the Sun-Earth L(sub 1) Lagrange point for return to the Earth.

  4. 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.

  5. The Genesis of tectonically and hydrothermally controlled industry mineral deposits: A geochemical and structural study

    NASA Astrophysics Data System (ADS)

    Wölfler, Anke; Prochaska, Walter; Henjes-Kunst, Friedhelm; Fritz, Harald

    2010-05-01

    The study aims to investigate the role of hydrothermal fluids in the formation of talc and magnesite deposits. These deposits occur in manifold geological and tectonical settings such as stockworks and veins within ultramafite hostrocks and monomineralic lenses within marine platform sediments. Along shear zones talc mineralizations may occur as a result of tectonical and hydrothermal activity. To understand the role of the fluids for the genesis of the mineralization, deposits in different geological and tectonical settings are investigated: Talc mineralization within in magnesite in low-grade palaeozoic nappe complexes (Gemerska Poloma, Slovakia): The magnesite body lies within the Gemer unit of the Inner Carpathians consisting of Middle Triassic metacarbonates and Upper Triassic pelagic limestones and radiolarites. The talc mineralization is bound to crosscutting veins. Two metamorphic events can be distinguished, one during Variscan orogeny and one related to the Alpine orogeny leading to the formation of talc along faults in an Mg carbonate body (Radvanec et al, 2004).The origin of the fluids as well as the tectonic events leading to the mineralization is still widely unknown. Talc mineralization in shearzones within Palaeozoic meta sedimentary rocks (Sa Matta, Sardinia): Variscan granitoids intruded Palaeozoic meta sedimentary rocks and were overprinted be NE striking tectonic structures that host talc mineralizations. The origin of Mg and fluids leading to the mineralization is still not answered satisfactorily (Grillo and Prochaska, 2007) and thus a tectonic model for the genesis of the talc deposit is missing. Talc mineralization within UHP pre-Alpine continental crust (Val Chisone, Italy): The talc deposit forms part of the Dora-Maira Massif. Geologicaly the massif derived from a Variscan basement that includes post-Variscan intrusions. The talc mineralization occurs as a sheetlike, conformable body. A possible tectonic emplacement of talc along shear

  6. LCSs in tropical cyclone genesis

    NASA Astrophysics Data System (ADS)

    Rutherford, B.; Montgomery, M. T.

    2011-12-01

    The formation of tropical cyclones in the Atlantic most often occurs at the intersection of the wave trough axis of a westward propagating African easterly wave and the wave critical latitude. Viewed in a moving reference frame with the wave, a cat's eye region of cyclonic recirculation can be seen in streamlines prior to genesis. The cat's eye recirculation region has little strain deformation and its center serves as the focal point for aggregation of convectively generated vertical vorticity. Air inside the cat's eye is repeatedly moistened by convection and is protected from the lateral intrusion of dry air. Since the flow is inherently time-dependent, we contrast the time-dependent structures with Eulerian structures of the wave-relative frame. Time-dependence complicates the kinematic structure of the recirculation region as air masses from the outer environment are allowed to interact with the interior of the cat's eye. LCSs show different boundaries of the cat's eye than the streamlines in the wave-relative frame. These LCSs are particularly important for showing the pathways of air masses that interact with the developing vortex, as moist air promotes development by supporting deep convection, while interaction with dry air impedes development. We primarily use FTLEs to locate the LCSs, and show the role of LCSs in both developing and non-developing storms. In addition, we discuss how the vertical coherence of LCSs is important for resisting the effects of vertical wind shear.

  7. A genesis of special relativity

    NASA Astrophysics Data System (ADS)

    Messager, Valérie; Letellier, Christophe

    2015-07-01

    The genesis of special relativity is intimately related to the development of the theory of light propagation. When optical phenomena were described, there are typically two kinds of theories: (i) One based on light rays and light particles and (ii) one considering the light as waves. When diffraction and refraction were experimentally discovered, light propagation became more often described in terms of waves. Nevertheless, when attempts were made to explain how light was propagated, it was nearly always in terms of a corpuscular theory combined with an ether, a subtle medium supporting the waves. Consequently, most of the theories from Newton's to those developed in the 19th century were dual and required the existence of an ether. We therefore used the ether as our Ariadne thread for explaining how the principle of relativity became generalized to the so-called Maxwell equations around the 1900's. Our aim is more to describe how the successive ideas were developed and interconnected than framing the context in which these ideas arose.

  8. Textural and petrological characteristics of ultrahigh-pressure chromitites, indicating a mantle recycling origin?

    NASA Astrophysics Data System (ADS)

    Arai, Shoji; Miura, Makoto; Yamamoto, Shinji; Shmelev, Vladimir

    2013-04-01

    Podiform chromitites, which occur as irregular to lens-like chromite-rich bodies within mantle peridotite in ophiolites, show various petrological characteristics, suggesting various origins. Some of them contain ultrahigh-pressure (UHP) minerals such as diamond, moissanite and Fe silicides (= UHP chromitites) (e.g., Robinson et al., 2004; Yang et al., 2007). Their origin is highly enigmatic, because the podiform chromitites have been widely understood as low-P (uppermost mantle level) products (e.g., Arai and Yurimoto, 1994; Zhou et al., 1994). Ordinary podiform chromitites show various lines of evidence for low-P genesis. Chromian spinel (or chromite) frequently contains solid mineral inclusions, and one of their main phases is pargasite, which is stable up to 3 GPa (e.g., Niida and Green, 1999), one of typical low-P minerals. The melt-harzburgite intereaction is a fundamental process in podiform chromitite genesis (e.g., Arai and Yurimoto, 1994), and associated with incongruent melting of orthopyroxene in harzburgite to form dunite and relatively Si-rich melt, which is operative at low-P conditions (e.g., Kushiro, 1969). We are strongly required to incorporate the genesis UHP chromitite into the framework of podiform chromitite genesis. Arai (2010) proposed a hypothesis of deep mantle recycling of ordinary low-P chromitite for the genesis of UHP chromitite. We try to examine petrographical and petrological characteristics of UHP chromitites to check the hypothesis of Arai (2010). Some peculiar textures of podiform chromities, such as orbicular, nodular and anti-nodular textures, are interpreted to be primary igneous and particular to ordinary low-P igneous chromitites (cf. Nicolas, 1989). To be interesting, the nodular texture, characterized by oval aggregates of chromian spinel (= chromite nodules; ~1 cm across) set in olivine-rich matrix, is also observed in some of UHP chromitites from the Luobusa ophiolite, Tibet (e.g., Yamamoto et al., 2009). We carefully

  9. The Genesis of the AFMLTA and Babel and the Babel of Genesis

    ERIC Educational Resources Information Center

    Vale, David

    2006-01-01

    In this article, the author describes the genesis of the Australian Federation of Modern Language Teachers Associations (AFMLTA) and "Babel." With regard to the origin of the title of the journal, its name refers only indirectly to the Tower of Babel in Genesis. It comes in fact from the affectionate nickname that had been given to the building at…

  10. New Results from the Flare Genesis Experiment

    NASA Astrophysics Data System (ADS)

    Rust, D. M.; Bernasconi, P. N.; Eaton, H. A.; Keller, C.; Murphy, G. A.; Schmieder, B.

    2000-05-01

    From January 10 to 27, 2000, the Flare Genesis solar telescope observed the Sun while suspended from a balloon in the stratosphere above Antarctica. The goal of the mission was to acquire long time series of high-resolution images and vector magnetograms of the solar photosphere and chromosphere. Images were obtained in the magnetically sensitive Ca I line at 6122 Angstroms and at H-alpha (6563 Angstroms). The FGE data were obtained in the context of Max Millennium Observing Campaign #004, the objective of which was to study the ``Genesis of Solar Flares and Active Filaments/Sigmoids." Flare Genesis obtained about 26,000 usable images on the 8 targeted active regions. A preliminary examination reveals a good sequence on an emerging flux region and data on the M1 flare on January 22, as well as a number of sequences on active filaments. We will present the results of our first analysis efforts. Flare Genesis was supported by NASA grants NAG5-4955, NAG5-5139, and NAG5-8331 and by NSF grant OPP-9615073. The Air Force Office of Scientific Research and the Ballistic Missile Defense Organization supported early development of the Flare Genesis Experiment.

  11. Mineralogy, petrology and chemistry of ANT-suite rocks from the lunar highlands

    NASA Technical Reports Server (NTRS)

    Prinz, M.; Keil, K.

    1977-01-01

    Anorthositic-noritic-troctolitic (ANT) rocks are the oldest and most abundant rocks of the lunar surface, and comprise about 90% of the suite of the lunar highlands. Consideration is given to the mineralogy, petrology, bulk chemistry, and origin of ANT-suite rocks. Problems associated in classifying and labeling lunar highland rocks because of textural complexities occurring from impact modifications are discussed. The mineralogy of ANT-suite rocks, dominated by plagioclase, olivine and pyrozene, and containing various minor minerals, is outlined. The petrology of ANT-suite rocks is reviewed along with the major element bulk composition of these rocks, noting that they are extremely depleted in K2O and P2O5. Various models describing the origin of ANT-suite rocks are summarized, and it is suggested that this origin involves a parental liquid of high-alumina basalt with low Fe/Fe+Mg.

  12. Genesis Capsule Yields Solar Wind Samples

    NASA Astrophysics Data System (ADS)

    Wiens, Roger C.; Burnett, Donald S.; Stansbery, Eileen K.; McNamara, Karen M.

    2004-11-01

    NASA's Genesis capsule, carrying the first samples ever returned from beyond the Moon, took a hard landing in the western Utah desert on 8 September after its parachutes failed to deploy. Despite the impact, estimated at 310 km per hour, some valuable solar wind collector materials have been recovered. With these samples, the Genesis team members are hopeful that nearly all of the primary science goals may be met. The Genesis spacecraft was launched in August 2001 to collect and return samples of solar wind for precise isotopic and elemental analysis. The spacecraft orbited the Earth-Sun Lagrangian point (L1), ~1.5 million km sunward of the Earth, for 2.3 years. It exposed ultrapure materials-including wafers of silicon, silicon carbide, germanium, chemically deposited diamond, gold, aluminum, and metallic glass-to solar wind ions, which become embedded within the substrates' top 100 nm of these materials.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Richards, Mark; Ridley, Victoria

    2010-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Ridley, Victoria A.; Richards, Mark A.

    2010-09-01

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

  16. Correlation between petrological, geochemical and tectonic segmentation within the North Atlantic

    NASA Astrophysics Data System (ADS)

    Sushchevskaya, N. M.; Cherkashov, G. A.; Tamaki, K.; Belyatsky, B. V.

    2003-04-01

    The possible primary rift melt compositions and its fractionation conditions under the various regions of spreading centers were determined on the base of the detail petrological and geochemical study of quenched glasses and basalts of Mohns-Knipovich Ridge. The forming Knipovich and Gakkel ridges coincide with the coldest zones of the oceanic lithosphere and are characterized by tholeiites enriched in Na, Si and poor in Fe. According lithophile elements distribution normalized to the primitive mantle the tholeiites are weakly enriched with maximum in Nb and minimum in Th, which are characteristic not only for the basalts of Knipovich and Gakkel ridges (Muhe, 1997), but for the Mohns and Kolbeinsey and alkaline basalts of Jan Mayen bank (Haase, 1996). Sr, Nd, Pb isotope data for the melts of Mohns and Knipovich ridges form the single mixing trend of enriched and depleted sources typical for Iceland basalts and differ from the lavas of Kolbeinsey ridge adjacent to Iceland (Mertz et al., 1991). Petrological segmentation of the North Atlantic appears and subordinates to geodynamic conditions, which are the results of global processes of deep diapirs uprising that is reflected in the tectonics of the region, but geochemical features of magmatism are caused by greater number of factors. For the North Atlantic region at the early stages of rift genesis there are determined depleted and weakly enriched tholeiites and the largest anomalies are connected with the regions of nonspreading parts of continental crust (Jan Mayen region). Enriched melts of ultra-slow spreading Knipovich ridge could be formed in the result of involving the low parts of adjacent continental blocks into the melting process with the following enriched melts migration and mantle flows into the spreading zones or due to the burying the formed melts and further melting of enriched mantle during the spreading axes jumping.

  17. [Petrological Analysis of Astrophysical Dust Analog Evolution

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  18. Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis

    NASA Astrophysics Data System (ADS)

    Libanov, M.; Mironov, S.; Rubakov, V.

    2016-08-01

    We study spatially flat bouncing cosmologies and models with the early-time Genesis epoch in a popular class of generalized Galileon theories. We ask whether there exist solutions of these types which are free of gradient and ghost instabilities. We find that irrespectively of the forms of the Lagrangian functions, the bouncing models either are plagued with these instabilities or have singularities. The same result holds for the original Genesis model and its variants in which the scale factor tends to a constant as t → ‑∞. The result remains valid in theories with additional matter that obeys the Null Energy Condition and interacts with the Galileon only gravitationally. We propose a modified Genesis model which evades our no-go argument and give an explicit example of healthy cosmology that connects the modified Genesis epoch with kination (the epoch still driven by the Galileon field, which is a conventional massless scalar field at that stage).

  19. Grants: Genesis of Some Funded Proposal Ideas

    ERIC Educational Resources Information Center

    Pazdar, John

    2011-01-01

    While "thinking outside the box" can be an over-used phase at times, in the world of grants it can provide the genesis of ideas. The "box" is the world of academia accepted by most educators, while "thinking outside" is the process that leads to grant ideas. In the grant world, "thinking outside the box" is a process of doing something that has…

  20. Interactive Storytelling: From the Book of Genesis

    ERIC Educational Resources Information Center

    Park, Keith

    2004-01-01

    Keith Park, advisory teacher for Sense (the National Deafblind Rubella Association) in Greenwich and Lewisham, London, has written about his approach to interactive storytelling for BJSE before. This article describes a series of poetry workshops based on chapters 37 to 45 of the Book of Genesis (the story of Joseph and his family) using the text…

  1. Finding the Genesis for a Thesis

    ERIC Educational Resources Information Center

    Caroll, Joyce Armstrong

    2013-01-01

    This article describes a prewriting heuristics strategy that can help students find the genesis of their thesis. The 3 functions of the heuristic procedure are that it aids in retrieving relevant information stored in the mind; draws attention to important information that can be further researched or accessed; and prepares the mind for the…

  2. 2.1-1.85 Ga tectonic events in the Yangtze Block, South China: Petrological and geochronological evidence from the Kongling Complex and implications for the reconstruction of supercontinent Columbia

    NASA Astrophysics Data System (ADS)

    Yin, Changqing; Lin, Shoufa; Davis, Donald W.; Zhao, Guochun; Xiao, Wenjiao; Li, Longming; He, Yanhong

    2013-12-01

    This paper presents petrography, zircon U-Pb ages and Hf isotopic data as well as whole-rock Sm-Nd isotopic data for mafic granulites, metapelitic rocks and high-grade marble from the Kongling Complex in the Yangtze Block, South China. Petrographic observations indicate that these three types of rocks experienced high-pressure metamorphism. Their mineral assemblages and P-T conditions define a clockwise P-T path involving isothermal decompression following the peak high-pressure metamorphism, which is considered to record a continent-continent collisional event. This is systematic documentation of the tectonic evolution of the Kongling Complex from 2.1-2.0 Ga deposition (constrained by youngest detrital zircon and metamorphic zircon) through ~ 2.0 Ga collision (high-pressure metamorphism) and syn-collisional partial melting (S-type granite and migmatization of TTG gneiss) to ~ 1.85 Ga post-collisional extension (A-type high-K granite and mafic dyke). These ages are broadly coincident with global collisional events (2.1-1.8 Ga) that led to the assembly of the Palaeo-Mesoproterozoic Columbia (or Nuna) supercontinent. Therefore, this study provides strong evidence that the Yangtze Block in South China was a component of the Columbia supercontinent.

  3. Taos Plateau Volcanic Project: A Vehicle for Integration of Concepts in Igneous Petrology

    NASA Astrophysics Data System (ADS)

    Henry, D.; Dutrow, B.

    2003-12-01

    Integrating concepts of igneous petrology is generally a challenge, but can be effective in the context of a project based on actual field, geochemical and geochronological data. The final lab project in the igneous portion of petrology involves a series of volcanic and associated rock samples that were collected from the Taos Plateau Volcanic Field, New Mexico, USA. Samples were collected over an area of several tens of km2 throughout the Plateau and represent a spatially and temporally correlated rock suite related to continental rifting. Rift-related magmatism encompasses much of the diversity of terrestrial magma types. Compositions of mafic magmas range from tholeiite to some of the most silica-undersaturated magmas found on the continents. Large effusive eruptions from fissures are typical of some rifts, whereas others may be dominated by central vent cones or even silicic caldera complexes. The injection of mantle-derived magma in extending crust may have a profound effect on the rheology of the crust and, therefore, the style of deformation associated with extension. Most of these aspects of rift volcanism and a wide range of mafic to silicic magma compositions are represented in the Rio Grande rift and the volcanic rocks of the Taos Plateau. In addition, much published data exists for whole rock and trace element geochemistry as well as geochronology. Rock samples and associated information are presented so that the student must integrate multiple lines of evidence, petrographic, petrologic, geochemical and geochronological data in a geospatial framework, to establish a geologic history of the region. The student must also draw on skills learned in mineralogy and structural geology furthering core geoscience education. Subsequent to the petrology course, the students visit the Taos Plateau Volcanic Field during their required field camp, thus reinforcing the linkage between the classroom setting and geologic reality.

  4. Petrology and U/Pb geochronology of the Santa Maria Ipalapa region in the southeastern part of the Xolapa Complex, Mexico: Constrains of the metamorphic evolution of the Xolapa Terrane

    NASA Astrophysics Data System (ADS)

    Gutiérrez Aguilar, F.; Victoria Morales, A.; Maldonado, R.

    2015-12-01

    The Xolapa Complex is a metamorphic-plutonic basement that forms a large belt with more than 600 km length and 50-100 km wide along the Pacific coast of southeastern Mexico. This Complex is constituted by a high grade sequence of meta-sedimentary and meta-igneous rocks, locally migmatisized, and which are intruded by strongly deformed plutonic rocks. Because of their representative characteristics, two samples were analyzed: 1) Para-schist: this rocks present a mineral assemblage composed of biotite, sillimanite, plagioclase, k-feldspar and garnet, and 2) Amphibolite: which are constituted by amphibole, plagioclase, biotite and garnet. The garnet porphydoblasts in the para-schist are subhedral, presents retrograde compositional zoning, with almandine and pyrope rich core (Alm74-75Sps7.-10.1Pyr12.1-12.5Grs3.8-3.9) and spessartine rich rim (Alm69-71Sps14-19Pyr7.9-9.6Grs3.6-3.7). The garnet in amphibolite, presents a prograde growth zoning with a slight increase in spessartine in the core (Alm59-60Grs24-25Pyr8.0-8.3Sps7.3-7.6), and low content of spessartine component toward the rim (Alm60-62Grs23-24Pyr8.8-9.6Sps5.4-5.5). In order to constrain the P-T evolution of the region, multiequilibria thermobarometry was applied to both samples, the para-schist unit presents P-T data from 706 (ºC) and 7.5 (kbar), in the other hand the garnet amphibolite unit shows P-T data from 734 (ºC) and 7 (kbar). This study provides new geochronological data (U/Pb in zircons) for the amphibolite facies metamorphism and for the migmatitic event in the region that contributes to the understanding of the tectonic evolution of southeastern Mexico.

  5. Petrology and Composition of HED Polymict Breccias

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Herrin, J. S.; Mertzman, S. A.; Mertzman, K. R.

    2010-01-01

    The howardite, eucrite and diogenite (HED) clan of meteorites forms the largest suite of achondrites with over 900 named members. The HEDs are igneous rocks and breccias of igneous rocks from a differentiated asteroid [1]. The consensus view is that these rocks hail from the asteroid 4 Vesta, which will be the first target of NASA's Dawn mission. When Dawn arrives at Vesta, she will begin remote imagery and spectroscopy of the surface. The surface she will observe will be dominated by rocks and soils mixed through impact gardening. To help with the interpretation of the remotely sensed data, we have begun a project on the petrologic and compositional study of a suite of HED polymict breccias. Here we report on the preliminary findings of this project.

  6. Petrology of brecciated ferroan noritic anorthosite 67215

    NASA Technical Reports Server (NTRS)

    Mcgee, James J.

    1988-01-01

    A petrologic study of breccia 67215 is presented, showing that the rock has the bulk composition of a ferroan noritic anorthosite and is a polymict breccia containing several lithic clast types within a crushed, cataclastic matrix. The dominant lithic clasts contained in breccia 67215 are found to be igneous and metamorphic low- and high- Ca pyroxenes and olivine. Other clasts include granulated and sheared clasts, coarse-grained anorthosite with relatively Fe-rich augite, aphanitic, feldspathic microporphyritic melt breccias, and an impact-melt rock with strongly zoned relatively Mg-rich pyroxene. It is concluded that this rock type is relatively common in the highlands regolith excavated by the North Ray Crater.

  7. Altering petrology through microbial dissimilatory phosphite oxidation

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Figueroa, I.; Coates, J. D.

    2013-12-01

    Microbial enhanced oil recovery (MEOR) takes advantage of various microbial metabolisms to increase hydrocarbon and energy yield by improving oil flow and flood water sweep in a reservoir during tertiary recovery. Wormholing at the injection well is believed to be the result of the large drop in pressure when water exits the injection well and enters the unconsolidated reservoir matrix. One possible means of prevent this event is to consolidate the rock matrix immediately around the injection well to create a permeable zone of stable petrology. Many microbial processes are known to result in the precipitation of ionic components into their environment creating solid-phase minerals. Such processes could be judiciously applied to bind unconsolidated matrices in order to form a permeable concreted rock matrix, which would minimize wormholing events and thus improve floodwater sweep. However, to date, apart from the application of urea oxidation creating calcium carbonate precipitation, there has been little investigation of the applicability of these precipitated bioconcretions to MEOR strategies and none to control wormholing events. Here we present a novel approach to altering rock petrology to concrete unconsolidated matrices in the near well environment by the biogenesis of authigenic minerals through microbial dissimilatory phosphite oxidation. Desulfotignum phosphitoxidans, strain FiPS-3 is currently the only isolated organism capable of using phosphite (HPO32-) as an electron donor for growth. This process, known as dissimilatory phosphite oxidation (DPO), can be coupled to either sulfate reduction or homoacetogenesis and leads to the accumulation of inorganic phosphate in the medium. The resulting insoluble mineral phases can coat the rock environment resulting in a concretion binding the unconsolidated matrix particles into a single phase. In this study we demonstrate that DPO can effectively produce calcium or magnesium phosphate minerals in packed glass

  8. Acidic Plutonism in the Izu-Ogasawara (Bonin)-Mariana (IBM) Arc and Growth of Arc Crust: Petrological and Geochemical Characteristics of the Tonalite at the Komahashi-Daini Seamount and Difference From the Tanzawa Plutonic Complex

    NASA Astrophysics Data System (ADS)

    Haraguchi, S.; Ishii, T.

    2003-12-01

    Recent seismic refraction and reflection data suggest that the continents are underlain by mafic lower crust and felsic middle crust. Petrogenesis of granitic middle crust layers is important for understanding the formation and evolution of continental crust. In modern tectonic regimes, tonalitic rocks and chemically equivalent volcanic rocks occur in island arcs and active continental margins. Thus, the petrogenesis of tonalite and related rocks in intra-oceanic arc settings is of great importance in understanding the processes of both recent island arc and continental crust formation. The Komahashi-Daini Seamount, in the northern Kyushu-Palau Ridge in the northern Philippine Sea plate, was investigated by the Japanese Geodynamics Project (GDP) cruises in the 1970's, and by the R/V Tansei-maru (Ocean Research Institute, University of Tokyo) in the 1990's. Plutonic rocks were dredged from the seamount, and have great importance for understanding the processes of island arc and continental crust formation. The petrographical and geochemical characteristics of the Komahashi-Daini Seamount tonalite are summarized as follows: (1) These tonalites are classified into biotite-hornblende tonalite and hornblende tonalite. Phenocrysts, especially plagioclase, show common lamellar twins and oscillatory zoning patterns; (2) This tonalite show low content of bulk LILE, and classified into low-K calc-alkaline, 1 to 8 wt.% MgO with 55 to 75 wt.% SiO2; (3) This tonalite shows roughly parallel and increasing total REE content with increasing SiO2 content, except for increasingly strong negative Eu anomaly at higher SiO2. These factors indicate that the Komahashi-Daini Seamount tonalite was produced by fractional crystallization. The parent magma of this tonalite is considered lower than 56 wt.% SiO2. Based on this relationship, we concluded that the source for the parental magma was arc mantle peridotite. We compared these tonalites with typical tonalite, i.e., Tanzawa Complex

  9. A Virtual Petrological Microscope for All Apollo 11 Lunar Samples

    NASA Technical Reports Server (NTRS)

    Pillnger, C. T.; Tindle, A. G.; Kelley, S. P.; Quick, K.; Scott, P.; Gibson, E. K.; Zeigler, R. A.

    2014-01-01

    A means of viewing, over the Internet, polished thin sections of every rock in the Apollo lunar sample collections via software, duplicaing many of the functions of a petrological microscope, is described.

  10. Petrology and Bulk Chemistry of R Chondrites: New Data

    NASA Astrophysics Data System (ADS)

    Isa, J.; Rubin, A. E.; Wasson, J. T.

    2010-03-01

    New INAA data show that R chondrites of all petrologic types are isochemical. R3 PRE 95411 contains numerous awaruite grains; R6 Y 980702 has a fine-grained granoblastic matrix; MET 01149 is reclassified as R3.

  11. Petrology in Action: Teaching Volcanology in the Undergraduate Curriculum

    NASA Astrophysics Data System (ADS)

    Harpp, K. S.

    2003-12-01

    Most petrology classes include description of volcanic systems as part of igneous petrology. The field of volcanology presents an opportunity for students to apply petrologic principles to physical processes with which they are familiar and to exemplify active magmatic processes that occur on relatively short time scales. As an illustration of the pedagogical connections between physical volcanology and igneous petrology, several classroom and lab exercises are described, including: a) analog experiments to illustrate rheological properties of magmas and how they vary with differing magmatic compositions; b) guided inquiry explorations of the role of magma composition on eruptive style and frequency; c) a sequence of demonstrations to illustrate physical principles of volcanic eruptions; d) problem sets using data from recent eruptions; and e) simulation of a volcanic monitoring crisis. The activities and demonstrations presented here illustrate a variety of applications of petrologic concepts, with an emphasis on the relationship between magmatic composition and its physical properties and how these physical properties in turn dictate the behavior of volcanic systems. They can be easily modified to illustrate magma chamber processes. These exercises are designed primarily for sophomore-level undergraduates and can be carried out in classrooms with a minimum of resources. The emphasis on hands-on inquiry exercises, coupled with the dynamic nature of some of these demonstrations gives students a chance to visualize petrologic processes that drive some of Earth's most dramatic events.

  12. A virtual petrological microscope for teaching and outreach

    NASA Astrophysics Data System (ADS)

    Kelley, Simon P.; Whalley, Peter; Tindle, Andrew G.; Anand, Mahesh

    2010-05-01

    Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. The alternative, although not replacing physical microscopes, offers the opportunity for enhancement and enrichment of laboratory experience in geoscience. An on-line microscope can also be used to engage the public with access to rare rocks such as meteorites and lunar samples. The focus of petrological microscope study in higher education is not primarily related to learning facts but is concerned with learning how to discriminate and classify within the paradigms of the discipline. In this case, the recognition and measurement of key features in rock samples in hand specimen and thin section. Whilst undertaking the practical exercise of recognition and naming of rock samples students are really being required to develop an understanding of the rock cycle as a model representing the relationship between rock categories and the process of their formation. The problems of teaching with complex visual materials, in effect of teaching learners 'how to see' from the scientific perspective of a particular discipline, are quite general. It could reasonably be expected that lessons learnt from the implementation and detailed evaluation of the proposed web-based system will generalise to many other topics in science education. Thus we focussed on the thin section images rather than reproducing a system that resembled a physical microscope. The virtual petrological microscope developed for a course at the Open University UK enables student acquisition of skills such as mineral and rock recognition using a browser window to explore thin sections of rocks as if they were using a laboratory microscope. The microscope allows students to pan around the thin

  13. From static to dynamic provenance analysis-Sedimentary petrology upgraded

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo

    2016-05-01

    The classical approach to sandstone petrology, established in the golden years of plate tectonics and based on the axiom that "detrital modes of sandstone suites primarily reflect the different tectonic settings of provenance terranes," has represented a benchmark for decades. The composition of sand and sandstone, however, simply provides us with a distorted image of the lithological structure of source terranes and gives us little clue whether they are allochthonous or autochthonous, orogenic or anorogenic, young or old. What we may able to see reflected in detrital modes is the nature of source terranes (continental, arc, oceanic) and the tectonostratigraphic level reached by erosion in space and time. The proposed new approach to the petrology of sand and sandstone (1) starts with a simple classification scheme circulated since the 1960s, which is purely descriptive, objective, and free of ill-defined ambiguous terms and (2) focuses on the nature and tectonostratigraphic level of source terranes. Further steps are essential to upgrade provenance analysis. Acquiring knowledge from modern settings is needed to properly identify and wherever possible correct for physical and chemical processes introducing environmental and diagenetic bias and thus address nature's complexities with adequate conceptual tools. Equally important is the integration of multiple techniques, ideally including bulk-sediment, multi-mineral, and single-mineral methods. Bulk-sediment petrography remains the fundamental approach that allows us to capture the most precious source of direct provenance information, represented by the mineralogy and texture of rock fragments. Bulk-sediment geochemistry, applicable also to silt and clay carried in suspension, is a superior method to check for hydraulic sorting, chemical weathering, and fertility of detrital minerals in different sediment sources. Detrital geochronology, thermochronology, and isotope geochemistry reveal the diverse time structures

  14. Slip rate and tremor genesis in Cascadia

    NASA Astrophysics Data System (ADS)

    Wech, Aaron G.; Bartlow, Noel M.

    2014-01-01

    At many plate boundaries, conditions in the transition zone between seismogenic and stable slip produce slow earthquakes. In the Cascadia subduction zone, these events are consistently observed as slow, aseismic slip on the plate interface accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides spatially and temporally with tremor, leaving the physics of tremor genesis poorly understood. Here we analyze seismic, geodetic, and strainmeter data in Cascadia to observe for the first time a large, tremor-generating slow earthquake change from tremor-genic to silent and back again. The tremor falls silent at reduced slip speeds when the migrating slip front pauses as it loads the stronger adjacent fault segment to failure. The finding suggests that rheology and slip-speed-regulated stressing rate control tremor genesis, and the same section of fault can slip both with and without detectable tremor, limiting tremor's use as a proxy for slip.

  15. Genesis and intersubjectivity: levels of mediation.

    PubMed

    Yamamoto, Toshiya

    2012-09-01

    I will make a brief comment on the thesis of José C. Loredo-Narciandi and José C. Sánchez-González (2012) "Neither Dichotomies Nor Dualism; Simply Genesis". Denying any reductionism and reification, they insists the importance of inseparable relation between subject and object, then discuss about genesis. I pointed out that their argument lacks an important element, i.e., mediator that differ from mere physical object. After discussing mediators nature, I discriminate the three level of interaction which mediated by mediator. The first is the pre-interaction level, the second is physical interaction level and the third is sign or language interaction level. The last argument of mine is about how we can solve the problem of reification and reductionism. In the argument it is pointed out that intersubjectivity is key concept for understanding and solving the problem appropriately. PMID:22628155

  16. Genesis Reentry Observations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Suggs, R. M.; Swift, W. R.

    2005-01-01

    The Genesis spacecraft reentry represented a unique opportunity to observe a "calibrated meteor" from northern Nevada. Knowing its speed, mass, composition, and precise trajectory made it a good subject to test some of the algorithms used to determine meteoroid mass from observed brightness. It was also a good test of an inexpensive set of cameras that could be deployed to observe future shuttle reentries. The utility of consumer-grade video cameras was evident during the STS-107 accident investigation, and the Genesis reentry gave us the opportunity to specify and test commercially available cameras that could be used during future reentries. This Technical Memorandum describes the video observations and their analysis, compares the results with a simple photometric model, describes the forward scatter radar experiment, and lists lessons learned from the expedition and implications for the Stardust reentry in January 2006 as well as future shuttle reentries.

  17. Cleaning Study of Genesis Sample 60487

    NASA Technical Reports Server (NTRS)

    Kuhlman, Kim R.; Rodriquez, M. C.; Gonzalez, C. P.; Allton, J. H.; Burnett, D. S.

    2013-01-01

    The Genesis mission collected solar wind and brought it back to Earth in order to provide precise knowledge of solar isotopic and elemental compositions. The ions in the solar wind were stopped in the collectors at depths on the order of 10 to a few hundred nanometers. This shallow implantation layer is critical for scientific analysis of the composition of the solar wind and must be preserved throughout sample handling, cleaning, processing, distribution, preparation and analysis. Particles of Genesis wafers, brine from the Utah Testing Range and an organic film have deleterious effects on many of the high-resolution instruments that have been developed to analyze the implanted solar wind. We have conducted a correlative microscopic study of the efficacy of cleaning Genesis samples with megasonically activated ultrapure water and UV/ozone cleaning. Sample 60487, the study sample, is a piece of float-zone silicon from the B/C array approximately 4.995mm x 4.145 mm in size

  18. Petrology and radiogeology of the Stripa pluton

    SciTech Connect

    Wollenberg, Harold; Flexser, Steve; Andersson, Lennart

    1980-12-01

    To better define the character of the rock encompassing the thermomechanical and hydrological experiments at the Stripa mine in central Sweden, and to help determine the size of the Stripa pluton, detailed studies were conducted of the petrology and radiogeology of the quartz monzonite and adjacent rocks. Petrologic studies emphasized optical petrography, with supplementary X-ray diffraction, X-ray fluorescence and microprobe analyses. Radiogeologic investigations were based primarily on surface and underground gamma-ray spectrometric measurements of uranium, thorium and potassium, supplemented by laboratory gamma spectrometric analyses and fission-track radiographic determinations of the locations and abundance of uranium in the rock matrix. Both the quartz monzonite and the metavolcanic leptite which it intruded are strongly fractured. Two stages of fracture filling are evident; an earlier stage encompassing quartz, sericite, feldspar, epidote, and chlorite, and a later stage dominated by carbonate minerals. The Stripa quartz monzonite is chemically and mineralogically distinct from other plutons in the region. Muscovite is the predominant mica in the quartz monzonite; biotite has been altered to chlorite, hornblende is absent, and accessory minerals are scarce. In contrast, in other plutons in the Stripa region biotite and hornblende are prominent mafic minerals and accessory minerals are abundant. The Stripa quartz monzonite is also considerably more radioactive than the leptite and other plutons in the region. Uranium and thorium abundances are both- 30 ppm, considerably higher than in "normal" granitic rocks where the thorium-to-uranium ratio generally exceeds 2. Potassium-argon dating of muscovite from the Stripa quartz monzonite indicates that this rock may be older, at 1691 million years than granitic rock of the neighboring Gusselby and Kloten massifs, whose ages, based on K-Ar dating of biotite, are respectively 1604 and 1640 m.y. Heat flow and heat

  19. Geology and petrology of the Early Precambrian of the Kodar-Udokan region

    NASA Astrophysics Data System (ADS)

    Krivenko, Valentin Afanas'evich; Pinaeva, Tat'iana Aleksandrovna

    This book presents the results of studies on the geological structure and petrological characteristics of the layered Archean formations of the western part of the Aldan-Stanovoi region (the Kodar-Udokan region). On the basis of these results, it is concluded that the stratified Archean is in fact a polygenic-polychronous laminated megacomplex that was formed in the course of the Archean and the Early Poterozoic periods. This complex includes major crystalline schists, hypersthenic diorites, enderbites, charnockites, granite and plagiogranite gneisses, blastomylonites, and metasomatites. A novel scheme is proposed for the geological partition of the Kodar-Udokan Early Precambrian.

  20. SNC meteorites - Clues to Martian petrologic evolution?

    NASA Astrophysics Data System (ADS)

    McSween, H. Y.

    1985-11-01

    Shergottites, nakhlites and the Chassigny meteorites (SNC group) may have originated on Mars. The shergottites are medium-grained basalts, the nakhlites are pyroxenites and the Chassigny is a dunite. The SNC group is petrologically diverse but differs from all other known achondrites in terms of mineral chemistry, the redox state, the oxygen isotopic composition and the radiometric ages. The SNC stones are mafic and ultramafic cumulate rocks with mineralogies that indicate rapid cooling and crystallization from tholeiitic magmas which contained water and experienced a high degree of oxidation. The characteristics suggest formation from a large parent body, i.e., a planet, but not earth. The estimated ages for the rocks match the estimated ages for several mapped Martian volcanoes in the Tharsis region. Additionally, the elemental and isotopic abundances of atmospheric gases embedded in melts in the SNC stones match Viking Lander data for the Martian atmosphere. However, reasons are cited for discounting the possibility that a large meteorite(s) collided with Mars about 180 myr ago and served as the mechanism for ejecting the SNC stones to earth.

  1. Timing and genesis of the adakitic and shoshonitic intrusions in the Laoniushan complex, southern margin of the North China Craton: Implications for post-collisional magmatism associated with the Qinling Orogen

    NASA Astrophysics Data System (ADS)

    Ding, Li-Xue; Ma, Chang-Qian; Li, Jian-Wei; Robinson, Paul T.; Deng, Xiao-Dong; Zhang, Chao; Xu, Wang-Chun

    2011-10-01

    The NWW-striking Qinling Orogen formed in the Triassic by collision between the North China and Yangtze Cratons. Triassic granitoid intrusions, mostly middle- to high-K, calc-alkaline, are widespread in this orogen, but contemporaneous intrusions are rare in the southern margin of the North China Craton, an area commonly considered as the hinterland belt of the orogen. In this paper, we report zircon U-Pb ages, elemental geochemistry, and Sr-Nd-Hf isotope data for the Laoniushan granitoid complex that was emplaced in the southern margin of the North China Craton. Zircon U-Pb dating shows that the complex was emplaced in the late Triassic (228 ± 1 to 215 ± 4 Ma), indicating that it is part of the post-collisional magmatism in the Qinling Orogen. The complex consists of, from early to late, biotite monzogranite, quartz diorite, quartz monzonite, and hornblende monzonite, which span a wide compositional range, e.g., SiO 2 = 55.9-70.6 wt.%, K 2O + Na 2O = 6.6-10.2 wt.%, and Mg # of 24 to 54. The biotite monzogranite has high Al 2O 3 (15.5-17.4 wt.%), Sr (396-1398 ppm) and Ba (1284-3993 ppm) contents and relatively high La/Yb (mostly 14-30) and Sr/Y (mostly 40-97) ratios, but low Yb (mostly 1.3-1.6 ppm) and Y (mostly14-19 ppm) contents, features typical of adakitic rocks. The quartz monzonite, hornblende monzonite and quartz diorite have a shoshonitic affinity, with K 2O up to 5.58 wt.% and K 2O/Na 2O ratios averaging 1.4. The rocks are characterized by strong LREE/HREE fractionation in chondrite-normalized REE pattern, without obvious Eu anomalies, and show enrichment in large ion lithophile elements but depletion in high field strength elements (Nb, Ta, Ti). The biotite monzogranite (228 Ma) has initial 87Sr/ 86Sr ratios of 0.7061 to 0.7067, ɛNd(t) values of - 9.2 to - 12.6, and ɛ Hf(t) values of - 9.0 to - 15.1; whereas the shoshonitic granitoids (mainly 217-215 Ma) have similar initial 87Sr/ 86Sr ratios (0.7065 to 0.7075) but more radiogenic ɛNd(t) (- 12.4 to

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    Your eyes are not deceiving you: Duck has submitted an abstract to a chondrite session. We will present the results of our petrological and compositional studies of R chondrites of diverse petrological type.

  3. The roles of fractional crystallization, magma mixing, crystal mush remobilization and volatile-melt interactions in the genesis of a young basalt-peralkaline rhyolite suite, the greater Olkaria volcanic complex, Kenya Rift valley

    USGS Publications Warehouse

    Macdonald, R.; Belkin, H.E.; Fitton, J.G.; Rogers, N.W.; Nejbert, K.; Tindle, A.G.; Marshall, A.S.

    2008-01-01

    The Greater Olkaria Volcanic Complex is a young (???20 ka) multi-centred lava and dome field dominated by the eruption of peralkaline rhyolites. Basaltic and trachytic magmas have been erupted peripherally to the complex and also form, with mugearites and benmoreites, an extensive suite of magmatic inclusions in the rhyolites. The eruptive rocks commonly represent mixed magmas and the magmatic inclusions are themselves two-, three- or four-component mixes. All rock types may carry xenocrysts of alkali feldspar, and less commonly plagioclase, derived from magma mixing and by remobilization of crystal mushes and/or plutonic rocks. Xenoliths in the range gabbro-syenite are common in the lavas and magmatic inclusions, the more salic varieties sometimes containing silicic glass representing partial melts and ranging in composition from anorthite ?? corundum- to acmite-normative. The peralkaline varieties are broadly similar, in major element terms, to the eruptive peralkaline rhyolites. The basalt-trachyte suite formed by a combination of fractional crystallization, magma mixing and resorption of earlier-formed crystals. Matrix glass in metaluminous trachytes has a peralkaline rhyolitic composition, indicating that the eruptive rhyolites may have formed by fractional crystallization of trachyte. Anomalous trace element enrichments (e.g. ??? 2000 ppm Y in a benmoreite) and negative Ce anomalies may have resulted from various Na- and K-enriched fluids evolving from melts of intermediate composition and either being lost from the system or enriched in other parts of the reservoirs. A small group of nepheline-normative, usually peralkaline, magmatic inclusions was formed by fluid transfer between peralkaline rhyolitic and benmoreitic magmas. The plumbing system of the complex consists of several independent reservoirs and conduits, repeatedly recharged by batches of mafic magma, with ubiquitous magma mixing. ?? The Author 2008. Published by Oxford University Press. All

  4. Thermal structure of the lithosphere: a petrologic model.

    PubMed

    Macgregor, I D; Basu, A R

    1974-09-20

    A preliminary evaluation of the thermal history of the upper mantle as determined by petrologic techniques indicates a general correspondence with theoretically derived models. The petrologic data supply direct information which may be used as an independent calibration of calculated models, serve as a base for evaluating the assumptions of the theoretical approach, and allow more careful selection of the variables describing mantle thermal properties and processes. Like the theoretical counterpart, the petrological approach indicates that the lithosphere is dominated by two thermal regimes: first, there is a continental regime which cools at rates of the order of 10(9) years and represents the longterm cooling of the earth. Secondly, superimposed on the continental evolution is the thermal event associated with the formation of an oceanic basin, and which may be thought of as a 10(8) year convective perturbation on the continental cycle. Of special interest is petrologic evidence for a sudden steepening of the thermal gradients across the lithosphere-asthenosphere boundary not seen in the theoretical models. The unexpected change of slope points to the need for a critical reevaluation of the thermal processes and properties extant in the asthenosphere. The potential of the petrologic contribution has yet to be fully realized. For a start, this article points to an important body of independent evidence critical to our understanding of the earth's thermal history. PMID:17738235

  5. Numerical Models of Ophiolite Genesis and Obduction

    NASA Astrophysics Data System (ADS)

    Guilmette, C.; Beaumont, C.; Jamieson, R.

    2013-12-01

    Ophiolites are relics of oceanic lithosphere tectonically emplaced in continental settings. They are diagnostic features of continental suture zones, where they mark past plate boundaries. Even after having been studied for more than 40 years, the mechanisms involved in the genesis and subsequent obduction of ophiolites over continental margins are still debated. We present the results of 2D thermal-mechanical numerical models that successfully reproduce characteristics of natural examples like the Semail, Bay of Islands, Yarlung-Zangbo, and Coast Range ophiolites. The numerical models are upper mantle scale and use pressure-, temperature- and strain-dependent viscous-plastic rheologies. Both divergent and convergent velocity boundary conditions are used and tectonic boundary forces are monitored. The models start with the rifting of a stable continent, followed by development of an ocean ridge and accretion of oceanic lithosphere at a total rate of 3 cm/y. Once a specified ocean size/age is achieved, the velocity boundary conditions are reversed leading to convergence and the spontaneous inception of a suduction zone at the mid-ocean ridge. We present results for models including different ages of oceans (40 to 90 Ma) and different convergence velocities (5 to 15 cm/y). The interaction between the lower plate passive margin and the oceanic upper plate results in 5 different tectonic styles. These differ mainly by the presence or absence of oceanic spreading in the upper plate (back-arc basin), leading to supra-subduction zone ophiolites vs. MORB-type, and by the behaviour of the oceanic slab, e.g., slab rollback vs. breakoff. The evolution of effective slab pull is interpreted to be the major control on the resulting tectonic style. Low effective slab pull models (young oceans and fast convergence rates) fail to obduct an ophiolite. Strong effective slab pull models (old oceans and lower convergence rates) result in subduction zone retreat and spontaneous oceanic

  6. 76 FR 73748 - Genesis Capital, LLC and Northern Lights Fund Trust; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-29

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Genesis Capital, LLC and Northern Lights Fund Trust; Notice of Application November 21, 2011... approval. Applicants: Genesis Capital, LLC (``Genesis Capital'' or the ``Adviser'') and Northern...

  7. Tropical cyclone genesis products at ECMWF

    NASA Astrophysics Data System (ADS)

    Prates, F.; Vitart, Frederic

    2009-09-01

    The operational ECMWF forecast system is nowadays able not only to analyse the current location of a tropical cyclone (TC) and predict its subsequent evolution, but also to predict the genesis of tropical cyclones, often several days before they occur. The advent of 4D-Var and assimilation of massive amounts of satellite data, combined with better model physics and an increase of horizontal/vertical resolution are among the numerous important changes made in the past with positive impact in TC forecast skill. Recent changes to the forecast system that have substantially improved the TC predictions are the increase in horizontal resolution in 2006, from T511 (40 km) to T799 (25 km) (T255 to T399 in the EPS), and improved model physics introduced in 2007. ECMWF generates a number of specific products for tropical cyclone forecasts. For each TC observed at initial time, a tracking algorithm is used to identify the successive positions of the TC throughout the forecast range. The tracker is applied to the deterministic T799 model and to each member of the EPS. The EPS tracks are used to generate strike probability maps. The tracking algorithm has recently been extended to identify and track new TCs that are predicted to appear during the forecast. Strike probability products for TC genesis have been developed and some cases will be selected to illustrate this product. Results from the objective verification package, upgraded to include the verification of TC genesis, will be presented and discussed, emphasising the impact on TC performance from recent changes in the forecast system.

  8. Petrologic evolution of the Louisville seamount chain

    NASA Astrophysics Data System (ADS)

    Hawkins, James W.; Lonsdale, Peter F.; Batiza, Rodey

    mantle source for the LSC seamounts remained remarkably homogeneous through the ˜66 m.y. recorded history of the chain. This is also supported by Nd and Sr isotope data for these samples. The mantle source must have been enriched in elements such as K, Rb, Ba, Y, REE relative to the source for N-MORB or to "primitive" mantle. The LSC seamounts have evolved through a petrologic sequence like that of the Hawaiian and Samoan Chains, but the long term homogeneity of the mantle source of LSC mag mas is in marked contrast to the heterogeneous mantle implied by the petrology of Hawaiian and Samoan volcanoes. A hotspot origin for the LSC seems likely: there may be an active "Loihi counterpart" yet to be found at the southeastern end of the chain.

  9. 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.

  10. The Genesis Mission: Contamination Control and Curation

    NASA Technical Reports Server (NTRS)

    Stansbery, E. K.

    2002-01-01

    The Genesis mission, launched in August 2001, is collecting samples of the solar wind and will return to Earth in 2004. Genesis can be viewed as the most fundamental of NASA's sample return missions because it is expected to provide insight into the initial elemental and isotopic composition of the solar nebula from which all other planetary objects formed. The data from this mission will have a large impact on understanding the origins and diversity of planetary materials. The collectors consist of clean, pure materials into which the solar wind will imbed. Science and engineering issues such as bulk purity, cleanliness, retention of solar wind, and ability to withstand launch and entry drove material choices. Most of the collector materials are installed on array frames that are deployed from a clean science canister. Two of the arrays are continuously exposed for collecting the bulk solar wind; the other three are only exposed during specific solar wind regimes as measured by ion and electron monitors. Other materials are housed as targets at the focal point of an electrostatic mirror, or "concentrator", designed to enhance the flux of specific solar wind species. Johnson Space Center (JSC) has two principal responsibilities for the Genesis mission: contamination control and curation. Precise and accurate measurements of the composition of the solar atoms require that the collector materials be extremely clean and well characterized before launch and during the mission. Early involvement of JSC curation personnel in concept development resulted in a mission designed to minimize contaminants from the spacecraft and operations. A major goal of the Genesis mission is to provide a reservoir of materials for the 21 51 century. When the collector materials are returned to Earth, they must be handled in a clean manner and their condition well documented. Information gained in preliminary examination of the arrays and detailed surveys of each collector will be used to

  11. Edge of chaos and genesis of turbulence.

    PubMed

    Chian, Abraham C-L; Muñoz, Pablo R; Rempel, Erico L

    2013-11-01

    The edge of chaos is analyzed in a spatially extended system, modeled by the regularized long-wave equation, prior to the transition to permanent spatiotemporal chaos. In the presence of coexisting attractors, a chaotic saddle is born at the basin boundary due to a smooth-fractal metamorphosis. As a control parameter is varied, the chaotic transient evolves to well-developed transient turbulence via a cascade of fractal-fractal metamorphoses. The edge state responsible for the edge of chaos and the genesis of turbulence is an unstable traveling wave in the laboratory frame, corresponding to a saddle point lying at the basin boundary in the Fourier space. PMID:24329334

  12. Genesis Solar Wind Samples: Update of Availability

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. P.; Allums, K. K.; Allton, J. H.

    2015-01-01

    The Genesis mission collected solar wind atoms for 28 months with a variety of collectors. The array wafer collector availability is displayed in the online catalog. The purpose of this report is to update the community on availability of array wafer samples and to preview other collectors which are in the process of being added to the online catalog. A total of fifteen pure materials were selected based on engineering and science requirements. Most of the materials were semiconductor wafers which were mounted on the arrays.

  13. Research on genesis of pyrite near the Permian-Triassic boundary in meishan, Zhejiang, China

    USGS Publications Warehouse

    Jiang, Y.-F.; Tang, Y.-G.; Chou, C.-L.

    2006-01-01

    The content and crystal forms of pyrite and sulfur isotope composition of pyrite sulfur as well as its vertical distribution near the Permian-Triassic (P/T) boundary in the Meishan section, Changxing county, Zhejiang province, China were studied using geological, petrological, mineralogical and geochemical methods (techniques). The result showed that the genesis of abundant pyrites in bed 24e2 at the uppermost part of the Changxing Formation in the Meishan section may be related to volcanic activity. In bed 24e2 of the Meishan section, pyrite has its highest content of 1.84% and the sulfur isotope composition has the highest ??34S value at + 2.2??? which is very similar to that of the average value of volcanic gas. There are some volcanic products such as ??-quartz, siliceous cylinders and siliceous spherules which coexisted with pyrites in beds 24e2 and 24f. It can be concluded that a large quantity of volcanic ash fell into the South China Sea and was incorporated into marine sediments during the formation of limestone at the uppermost part of the Changxing Formation. The volcanic eruption with massive amounts of H2S and S02 gas at the end of the Permian period resulted in the enrichment of H2S in the South China Sea areas. The reaction of H2S with reactive iron minerals formed the mass of abundant pyrites.

  14. The genesis of vertisols with gilgai microtopography: A review

    NASA Astrophysics Data System (ADS)

    Khitrov, N. B.

    2016-05-01

    Different hypotheses about the genesis of gilgai microtopography and corresponding soil complexes with clayey swelling soils are considered in this review. Their diversity is stipulated by specificities of the objects themselves and by the history of studies of the composition, properties, regimes, and landscape conditions of the areas with Vertisols in different countries. Most of the hypotheses about the genesis of Vertisols with the gilgai microtopography suggest that strong swelling-shrinking processes take place in these soils in the course of moistening-drying cycles; the origin of shear stress in the soils, its spatial patterns, and the particular ways of translocation of the soil material are discussed. At the early stage of Vertisol studies, a hypothesis about the leading role of the process of "self-swallowing" of the soils as a result of filling of open cracks with the material from the upper soil horizons was popular. However, numerous facts suggest that the intensity of this process is relatively low, so that it cannot play the major role in the gilgai formation and cyclic changes in the thickness and properties of the soil horizons in Vertisols. Another important mechanism is the uneven moistening and drying of the whole soil volume resulting in the irregular distribution of inner tensions in the soil with the development of shear stress and plastic deformation of the soil mass. The hypotheses suggested in the recent decades are based on the models of soil mechanics. A number of hypotheses consider possible alternation and duration of evolutionary stages of the development of Vertisols with the gilgai microtopography.

  15. Petrologically-based Electrical Profiles vs. Geophysical Observations through the Upper Mantle (Invited)

    NASA Astrophysics Data System (ADS)

    Gaillard, F.; Massuyeau, M.; Sifre, D.; Tarits, P.

    2013-12-01

    Mineralogical transformations in the up-welling mantle play a critical role on the dynamics of mass and heat transfers at mid-ocean-ridgeS. The melting event producing ridge basalts occur at 60 km depth below the ridge axis, but because of small amounts of H2O and CO2 in the source region of MOR-basalts, incipient melting can initiate at much greater depth. Such incipient melts concentrate incompatible elements, and are particularly rich in volatile species. These juices evolve from carbonatites, carbonated basalts, to CO2-H2O-rich basalts as recently exposed by petrological surveys; the passage from carbonate to silicate melts is a complex pathway that is strongly non-linear. This picture has recently been complicated further by studies showing that oxygen increasingly partitions into garnet as pressure increases; this implies that incipient melting may be prevented at depth exceeding 200 km because not enough oxygen is available in the system to stabilize carbonate melts. The aim of this work is twofold: - We modelled the complex pathway of mantle melting in presence of C-O-H volatiles by adjusting the thermodynamic properties of mixing in the multi-component C-O-H-melt system. This allows us to calculate the change in melt composition vs. depth following any sortS of adiabat. - We modelled the continuous change in electrical properties from carbonatites, carbonated basalts, to CO2-H2O-rich basalts. We then successfully converted this petrological evolution along a ridge adiabat into electrical conductivity vs. depth signal. The discussion that follows is about comparison of this petrologically-based conductivity profile with the recent profiles obtained by inversion of the long-period electromagnetic signals from the East-Pacific-Rise. These geophysically-based profiles reveal the electrical conductivity structure down to 400 km depth and they show some intriguing highly conductive sections. We will discuss heterogeneity in electrical conductivity of the upper

  16. Determination of the petrologic type of CV3 chondrites by Raman spectroscopy of included organic matter

    NASA Astrophysics Data System (ADS)

    Bonal, Lydie; Quirico, Eric; Bourot-Denise, Michèle; Montagnac, Gilles

    2006-04-01

    This paper reports the first reliable quantitative determination of the thermal metamorphism grade of a series of nine CV3 chondrites: Allende, Axtell, Bali, Mokoia, Grosnaja, Efremovka, Vigarano, Leoville, and Kaba. The maturity of the organic matter in matrix, determined by Raman spectroscopy, has been used as a powerful metamorphic tracer, independent of the mineralogical context and extent of aqueous alteration. This tracer has been used along with other metamorphic tracers such as Fe zoning in type-I chondrules of olivine phenocrysts, presolar grain abundance and noble gas abundance (bulk and P3 component). The study shows that the petrologic types determined earlier by Induced ThermoLuminescence were underestimated and suggests the following values: PT (Allende-Axtell) >3.6; PT (Bali-Mokoia-Grosnaja) ˜3.6; PT (Efremovka-Leoville-Vigarano) = 3.1-3.4; PT (Kaba) ˜3.1. The most commonly studied CV3, Allende, is also the most metamorphosed. Bali is a breccia containing clasts of different petrologic types. The attribution suggested by this study is that of clasts of the highest petrologic types, as pointed out by IOM maturity and noble gas bulk abundance. CV3 chondrites have complex asteroidal backgrounds, with various degrees of aqueous alteration and/or thermal metamorphism leading to complex mineralogical and petrologic patterns. (Fe,Mg) chemical zoning in olivine phenocrysts, on the borders of type I chondrules of porphyritic olivine- and pyroxene-rich textural types, has been found to correlate with the metamorphism grade. This suggests that chemical zoning in some chondrules, often interpreted as exchanges between chondrules and nebular gas, may well have an asteroidal origin. Furthermore, the compositional range of olivine matrix is controlled both by thermal metamorphism and aqueous alteration. This does not support evidence of a nebular origin and does not necessarily mirror the metamorphism grade through (Fe,Mg) equilibration. On the other hand, it may

  17. ORE's GENeric Evaluation SYStem: GENESYS 1988-89.

    ERIC Educational Resources Information Center

    Baenen, Nancy; And Others

    GENESYS--GENeric Evaluation SYStem--is a method of streamlining data collection and evaluation through the use of computer technology. GENESYS has allowed the Office of Research and Evaluation (ORE) of the Austin (Texas) Independent School District to evaluate a multitude of contrasting programs with limited resources. By standardizing methods and…

  18. The genesis of collective health in Brazil.

    PubMed

    Vieira-da-Silva, Ligia Maria; Pinell, Patrice

    2014-03-01

    During the 1970s in Brazil a social space directed towards health problems on the population level, called collective health, was created and institutionalised. To what extent did this Brazilian invention correspond to a specific socio-historical practice? The works published on this topic have considered social medicine as a homogeneous phenomenon without empirically studying the specificities of national experiences. To bridge this gap, a historical study on the genesis of collective health in Brazil was carried out based on Bourdieu's field theory. The interaction between the paths of the founders and the conditions of historical possibilities were researched through documentary and bibliographical sources, as well as through in-depth interviews of the founders. This social space originated from a meeting of agents with different social backgrounds but who interconnected, creating a structure that was independent of each agent considered individually. One of the components of this establishment was the joining of theoretical production and the implementation of health reforms that resulted in the organisation of a universal health system. This study attempts to show how the international political situation and the contradictions of the national crisis created a universe of possibilities, allowing for the genesis of this sui generis space in Brazil. PMID:24111568

  19. Genesis Ultrapure Water Megasonic Wafer Spin Cleaner

    NASA Technical Reports Server (NTRS)

    Allton, Judith H.; Stansbery, Eileen K.; Calaway, Michael J.; Rodriquez, Melissa C.

    2013-01-01

    A device removes, with high precision, the majority of surface particle contamination greater than 1-micron-diameter in size from ultrapure semiconductor wafer materials containing implanted solar wind samples returned by NASA's Genesis mission. This cleaning device uses a 1.5-liter/minute flowing stream of heated ultrapure water (UPW) with 1- MHz oscillating megasonic pulse energy focused at 3 to 5 mm away from the wafer surface spinning at 1,000 to 10,000 RPM, depending on sample size. The surface particle contamination is removed by three processes: flowing UPW, megasonic cavitations, and centripetal force from the spinning wafer. The device can also dry the wafer fragment after UPW/megasonic cleaning by continuing to spin the wafer in the cleaning chamber, which is purged with flowing ultrapure nitrogen gas at 65 psi (.448 kPa). The cleaner also uses three types of vacuum chucks that can accommodate all Genesis-flown array fragments in any dimensional shape between 3 and 100 mm in diameter. A sample vacuum chuck, and the manufactured UPW/megasonic nozzle holder, replace the human deficiencies by maintaining a consistent distance between the nozzle and wafer surface as well as allowing for longer cleaning time. The 3- to 5-mm critical distance is important for the ability to remove particles by megasonic cavitations. The increased UPW sonication time and exposure to heated UPW improve the removal of 1- to 5-micron-sized particles.

  20. Reheating and primordial gravitational waves in generalized Galilean genesis

    NASA Astrophysics Data System (ADS)

    Nishi, Sakine; Kobayashi, Tsutomu

    2016-04-01

    Galilean genesis is an alternative to inflation, in which the universe starts expanding from Minkowski with the stable violation of the null energy condition. In this paper, we discuss how the early universe is reheated through the gravitational particle production at the transition from the genesis phase to the subsequent phase where the kinetic energy of the scalar field is dominant. We then study the consequences of gravitational reheating after Galilean genesis on the spectrum of primordial gravitational waves. The resultant spectrum is strongly blue, and at high frequencies Ωgwpropto f3 in terms of the energy density per unit logarithmic frequency. Though this cannot be detected in existing detectors, the amplitude can be as large as Ωgw~ 10‑12 at f~ 100 MHz, providing a future test of the genesis scenario. The analysis is performed within the framework of generalized Galilean genesis based on the Horndeski theory, which enables us to derive generic formulas.

  1. Silicic Magma Genesis in Neogene Central Volcanoes in Northeast Iceland

    NASA Astrophysics Data System (ADS)

    Berg, S. E.; Troll, V. R.; Riishuus, M. S.; Burchardt, S.; Krumbholz, M.

    2012-04-01

    We report on a geological expedition to NE Iceland in August 2011. A comprehensive sample suite of intrusive and extrusive rocks, ranging from basaltic to silicic compositions, was collected from the Neogene silicic central volcanic complexes in the region between Borgarfjörður eystri and Loðmundarfjörður. The area contains the second-most voluminous occurrence of silicic rocks in Iceland, including caldera structures, inclined sheet swarms, extensive ignimbrite sheets, sub-volcanic rhyolites and silicic lava flows. Yet it is one of Iceland's geologically least known areas (c.f. Gústafsson, 1992; Martin & Sigmarsson, 2010; Burchardt et al., 2011). The voluminous occurrence of evolved rocks in Iceland (10-12 %) is very unusual for an ocean island or a mid-oceanic ridge, with a typical signal of magmatic bimodality, often called "Bunsen-Daly" compositional gap (e.g. Bunsen, 1851; Daly, 1925; Barth et al., 1939). The Bunsen-Daly Gap is a long-standing fundamental issue in petrology and difficult to reconcile with continuous fractional crystallization as a dominant process in magmatic differentiation (Bowen, 1928), implying that hydrothermal alteration and crustal melting may play a significant role. Our aim is to contribute to a solution of this issue by unravelling the occurrence of voluminous evolved rhyolites in NE Iceland. We will use a combined petrological, textural, experimental and in-situ isotope approach. We plan to perform major, trace element and Sr-Nd-Hf-Pb-He-O isotope geochemistry, as well as U/Pb and Ar/Ar geochronology on rocks and mineral separates. In addition, high pressure-temperature partial melting experiments aim to reproduce and further constrain natural processes. Using the combined data set we intend to produce a comprehensive and quantitative analysis of rhyolite petrogenesis, and of the temporal, structural and geochemical evolution of the silicic volcanism in NE Iceland. The chosen field area serves as a good analogue for active

  2. Review and update of the applications of organic petrology: Part 1, geological applications

    USGS Publications Warehouse

    Suárez-Ruiz, Isabel; Flores, Deolinda; Mendonça Filho, João Graciano; Hackley, Paul C.

    2012-01-01

    Organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry. Coal petrology was then considered a branch of coal science. Later, with the development of specialized nomenclature, classification of coal components, and the standardization and improvement of analytical (microscopical) methods, this discipline expanded in interests and name, becoming organic petrology. Organic petrology carries a broader context, being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources. At present, organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences. Throughout the 20th century several important monographs have been published on the discipline of organic petrology, including “Stach's textbook of coal petrology” (1st edition 1935, 2nd 1975, 3rd 1982), updated as the more general “Organic petrology” by Taylor et al. (1998). More recently, the text “Applied coal petrology: the role of petrology in coal utilization” was published by Suárez-Ruiz and Crelling (2008). This review is the first in a two-part review series that describes and updates the role of organic petrology in geosciences. A second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow.

  3. MitoGenesisDB: an expression data mining tool to explore spatio-temporal dynamics of mitochondrial biogenesis

    PubMed Central

    Gelly, Jean-Christophe; Orgeur, Mickael; Jacq, Claude; Lelandais, Gaëlle

    2011-01-01

    Mitochondria constitute complex and flexible cellular entities, which play crucial roles in normal and pathological cell conditions. The database MitoGenesisDB focuses on the dynamic of mitochondrial protein formation through global mRNA analyses. Three main parameters confer a global view of mitochondrial biogenesis: (i) time-course of mRNA production in highly synchronized yeast cell cultures, (ii) microarray analyses of mRNA localization that define translation sites and (iii) mRNA transcription rate and stability which characterize genes that are more dependent on post-transcriptional regulation processes. MitoGenesisDB integrates and establishes cross-comparisons between these data. Several model organisms can be analyzed via orthologous relationships between interspecies genes. More generally this database supports the ‘post-transcriptional operon’ model, which postulates that eukaryotes co-regulate related mRNAs based on their functional organization in ribonucleoprotein complexes. MitoGenesisDB allows identifying such groups of post-trancriptionally regulated genes and is thus a useful tool to analyze the complex relationships between transcriptional and post-transcriptional regulation processes. The case of respiratory chain assembly factors illustrates this point. The MitoGenesisDB interface is available at http://www.dsimb.inserm.fr/dsimb_tools/mitgene/. PMID:20833631

  4. Mesosiderites: A Chronologic and Petrologic Synthesis

    NASA Astrophysics Data System (ADS)

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

    1992-07-01

    Recent petrologic, chemical, and isotopic analyses of mesosiderite clasts and whole rocks allow construction of the evolutionary history of the mesosiderite parent body (MPB) as shown in the figure. I. Initial Melting ~4.56 Ga Ago. Numerous chronologic measurements indicate that initial melting of the MPB occurred shortly after accretion, at about the same time that the eucrites and angrites formed. For example, a zircon grain from a basaltic clast in Vaca Muerta yielded a Pb-Pb age of 4.563 Ga (Ireland and Wlotzka, 1992). The 4.56-Ga event on the MPB is probably responsible for forming the monogenic basaltic clasts that compositionally resemble typical eucrites (Rubin and Mittlefehldt, 1992). II. Crustal Remelting ~4.47 Ga Ago. Internal Sm-Nd isochron ages of 4.47 Ga have been determined for gabbroic pebble 12 from Vaca Muerta and a basaltic clast from Mt. Padbury (Stewart et al., 1991). Pebble 12 is one of many clasts in mesosiderites that are highly depleted in incompatible elements and probably represent remelted crustal rocks (Rubin and Mittlefehldt, 1992). Because variation of Fe/Mn with Fe/Mg in pyroxenes from these clasts follows a trend defined by FeO reduction from a melt (Mittlefehldt, 1990), and because the reducing agents (e.g., P) were likely to have been introduced during metal-silicate mixing, the age of pebble 12 indicates that metal-silicate mixing had to have occurred >=4.47 Ga ago. III. Localized Impact Melting 4.5-3.9 Ga Ago. Localized impact melting and metamorphism were widespread on the eucrite parent body as indicated by many ages that were partially or totally reset <4.56 Ga ago. Impact melt material is common in mesosiderites of all petrologic types, and ages between 4.5-3.9 Ga are preserved. Quench-textured pebble 5 from Vaca Muerta, which is likely to have formed from a localized impact melt of material resembling a cumulate eucrite (Rubin and Jerde, 1987), has an internal isochron age of 4.42 Ga (Stewart et al., 1992). The high

  5. The Mineralogy and Petrology of Anomalous Eucrite Emmaville

    NASA Technical Reports Server (NTRS)

    Barrett, T. J.; Mittlefehldt, D. W.; Ross, D. K.; Greenwood, R. C.; Anand, M.; Franchi, I. A.; Grady, M. M.; Charlier, B. L. A.

    2015-01-01

    It has long been known that certain basaltic achondrites share similarities with eucrites. These eucrite-like achondrites have distinct isotopic compositions and petrologic characteristics indicative of formation on a separate parent body from the howardite-eucrite-diogenite (HED) clan (e.g., Ibitira, Northwest Africa (NWA) 011). Others show smaller isotopic variations but are otherwise petrologically and compositionally indistinguishable from basaltic eucrites (e.g., Pasamonte, Pecora Escarpment (PCA) 91007). The Emmaville eucrite has a delta O-17 value of -0.137 plus or minus 0.024 per mille (1 sigma), which is substantially different from the eucrite mean of -0.246 plus or minus 0.014 per mille (2 sigma), but similar to those of A-881394 and Bunburra Rockhole (BR). Currently little data exist for Emmaville in terms of petrology or bulk composition. Studying anomalous eucrites allows us to more completely understand the numbers of asteroids represented by eucrite- like basalts and thus constrain the heterogeneity of the HED suite. In this study, we present our preliminary petrological and mineral composition results for Emmaville.

  6. A Simulated Research Problem for Undergraduate Metamorphic Petrology.

    ERIC Educational Resources Information Center

    Amenta, Roddy V.

    1984-01-01

    Presents a laboratory problem in metamorphic petrology designed to simulate a research experience. The problem deals with data on scales ranging from a geologic map to hand specimens to thin sections. Student analysis includes identifying metamorphic index minerals, locating their isograds on the map, and determining the folding sequence. (BC)

  7. Possible influence of dust on hurricane genesis

    NASA Astrophysics Data System (ADS)

    Bretl, Sebastian; Reutter, Philipp; Raible, Christoph C.; Ferrachat, Sylvaine; Lohmann, Ulrike

    2014-05-01

    Tropical Cyclones (TCs) belong to the most extreme events in nature. In the past decade, the possible impact of dust on Atlantic hurricanes receives growing interest. As mineral dust is able to absorb incoming solar radiation and therefore warm the surrounding air, the presence of dust can lead to a reduction of sea surface temperature (SST) and an increase in atmospheric stability. Furthermore, resulting baroclinic effects and the dry Saharan easterly jet lead to an enhanced vertical shear of the horizontal winds. SST, stability, moisture and vertical wind shear are known to potentially impact hurricane activity. But how Saharan dust influences these prerequisites for hurricane formation is not yet clear. Some dynamical mechanisms induced by the SAL might even strengthen hurricanes. An adequate framework for investigating the possible impact of dust on hurricanes is comparing high resolution simulations (~0.5°x0.5°, 31 vertical levels) with and without radiatively active dust aerosols. To accomplish this task, we are using the general circulation model ECHAM6 coupled to a modified version of the aerosol model HAM, ECHAM6-HAM-Dust. Instead of the five aerosol species HAM normally contains, the modified version takes only insoluble dust into account, but modifies the scavenging parameters in order to have a similar lifetime of dust as in the full ECHAM6-HAM. All remaining aerosols are prescribed. To evaluate the effects of dust on hurricanes, a TC detection and tracking method is applied on the results. ECHAM6-HAM-Dust was used in two configurations, one with radiatively active dust aerosols and one with dust being not radiatively active. For both set-ups, 10 Monte-Carlo simulations of the year 2005 were performed. A statistical method which identifies controlling parameters of hurricane genesis was applied on North Atlantic developing and non-developing disturbances in all simulations, comparing storms in the two sets of simulations. Hereby, dust can be assigned

  8. Petrology and Geochemistry of LEW 88663 and PAT 91501: High Petrologic L Chondrites

    NASA Astrophysics Data System (ADS)

    Mittlefehldt, D. W.; Lindstrom, M. M.; Field, S. W.

    1993-07-01

    Primitive achondrites (e.g., Acapulco, Lodran) are believed to be highly metamorphosed chondritic materials, perhaps up to the point of anatexis in some types. Low petrologic grade equivalents of these achondrites are unknown, so the petrologic transition from chondritic to achondritic material cannot be documented. However, there are rare L chondrites of petrologic grade 7 that may have experienced igneous processes, and study of these may yield information relevant to the formation of primitive achondrites, and perhaps basaltic achondrites, from chondritic precursors. We have begun the study of the L7 chondrites LEW 88663 and PAT 91501 as part of our broader study of primitive achondrites. Here, we present our preliminary petrologic and geochemical data on these meteorites. Petrology and Mineral Compositions: LEW 88663 is a granular achondrite composed of equant, subhedral to anhedral olivine grains poikilitically enclosed in networks of orthopyroxene and plagioclase. Small grains of clinopyroxene are spatially associated with orthopyroxene. Troilite occurs as large anhedral and small rounded grains. The smaller troilite grains are associated with the orthopyroxene-plagioclase networks. PAT 91501 is a vesicular stone containing centimeter-sized troilite +/- metal nodules. Its texture consists of anhedral to euhedral olivine grains, anhedral orthopyroxene grains (some with euhedral clinopyroxene overgrowths), anhedral to euhedral clinopyroxene, and interstitial plagioclase and SiO2-Al2O3-K2O- rich glass. In some areas, olivine is poikilitically enclosed in orthopyroxene. Fine-grained troilite, metal, and euhedral chromite occur interstitial to the silicates. Average mineral compositions for LEW 88663 are olivine Fo(sub)75.8, orthopyroxene Wo(sub)3.4En(sub)76.2Fs(sub)20.4, clinopyroxene Wo(sub)42.6En(sub)47.8Fs(sub)9.6, plagioclase Ab(sub)75.0An(sub)21.6Or(sub)3.4. Mineral compositions for PAT 91501 are olivine Fo(sub)73.8, orthopyroxene Wo(sub)4.5En(sub)74.8Fs

  9. Status of Genesis Mo-Pt Foils

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Allton, J. H.; Burnett, D. S.; Butterworth, A. L.; Caffee, M. W.; Clark, B.; Jurewicz, A. J. G.; Komura, K.; Westphal, A. J.; Welten, K. C.

    2005-01-01

    A total of 8,000 sq cm of Mo-coated Pt foils were exposed to solar wind for 884 days by the Genesis mission. Solar wind ions were captured in the surface of the Mo. Our objective is the measurement of long-lived radionuclides, such as Be-10, Al-26, Cl-36, and Mn-53, and short-lived radionuclides, such as Na-22 and Mn-54, in the captured sample of solar wind. The expected flux of these nuclides in the solar wind is 100 atom/sq cm yr or less. The hard landing of the SRC (Sample Return Capsule) at UTTR (Utah Test and Training Range) has resulted in contaminated and crumpled foils. Here we present a status report and revised plan for processing the foils.

  10. Short-lived radioactivity and magma genesis.

    PubMed

    Gill, J; Condomines, M

    1992-09-01

    Short-lived decay products of uranium and thorium have half-lives and chemistries sensitive to the processes and time scales of magma genesis, including partial melting in the mantle and magmatic differentiation in the crust. Radioactive disequilibrium between (238)U, (230)Th, and (226)Ra is widespread in volcanic rocks. These disequilibria and the isotopic composition of thorium depend especially on the extent and rate of melting as well as the presence and composition of vapor during melting. The duration of mantle melting may be several hundred millennia, whereas ascent times are a few decades to thousands of years. Differentiation of most magmas commonly occurs within a few millennia, but felsic ones can be tens of millennia old upon eruption. PMID:17738278

  11. De Novo Genesis of Enhancers in Vertebrates

    PubMed Central

    Eichenlaub, Michael P.; Ettwiller, Laurence

    2011-01-01

    Evolutionary innovation relies partially on changes in gene regulation. While a growing body of evidence demonstrates that such innovation is generated by functional changes or translocation of regulatory elements via mobile genetic elements, the de novo generation of enhancers from non-regulatory/non-mobile sequences has, to our knowledge, not previously been demonstrated. Here we show evidence for the de novo genesis of enhancers in vertebrates. For this, we took advantage of the massive gene loss following the last whole genome duplication in teleosts to systematically identify regions that have lost their coding capacity but retain sequence conservation with mammals. We found that these regions show enhancer activity while the orthologous coding regions have no regulatory activity. These results demonstrate that these enhancers have been de novo generated in fish. By revealing that minor changes in non-regulatory sequences are sufficient to generate new enhancers, our study highlights an important playground for creating new regulatory variability and evolutionary innovation. PMID:22069375

  12. Genesis: Removing Contamination from Sample Collectors

    NASA Technical Reports Server (NTRS)

    Lauer, H. V.; McNamara, K. M.; Westphal, Andrew; Butterworth, A. L.; Burnett, D. S.; Jurewicz, A.; Woolum, D.; Allton, J. H.

    2005-01-01

    The Genesis mission returned to Earth on September 8, 2004, experiencing a non-nominal reentry. The parachutes which were supposed to slow and stabilize the capsule throughout the return failed to deploy, causing the capsule to impact the desert floor at a speed of nearly 200 MPH. Both the science canister and the major components of the SRC were returned before nightfall on September 8 to the prestaged cleanroom at UTTR , avoiding prolonged exposure or pending weather changes which might further contaminate the samples. The majority of the contaminants introduced as a result of the anomalous landing were in the form of particulates, including UTTR dust and soil, carbon-carbon heat shield material, and shattered collector dust (primarily silicon and germanium). Additional information is included in the original extended abstract.

  13. Genesis Solar Wind Array Collector Cataloging Status

    NASA Technical Reports Server (NTRS)

    Burkett, P.J.; Rodriguez, M.C.; Calaway, M.C.; Allton, J.H.

    2009-01-01

    Genesis solar wind array collectors were fractured upon landing hard in Utah in 2004. The fragments were retrieved from the damaged canister, imaged, repackaged and shipped to the Johnson Space Center curatorial facility [1]. As of January 2009, the collection consists of 3460 samples. Of these, 442 are comprised into "multiple" sample groupings, either affixed to adhesive paper (177) or collected in jars (17), culture trays (87), or sets of polystyrene vials (161). A focused characterization task was initiated in May 2008 to document the largest samples in the collection. The task consisted of two goals: to document sapphire based fragments greater than 2 cm in one dimension, and to document silicon based fragments greater than 1 cm in one direction.

  14. Geophysical, petrological and mineral physics constraints on Earth's surface topography

    NASA Astrophysics Data System (ADS)

    Guerri, Mattia; Cammarano, Fabio; Tackley, Paul J.

    2015-04-01

    modeled topography. We also test several viscosity models, either radially symmetric, the V1 profile from Mitrovica and Forte [2004], or more complex laterally varying structures. All the property fields are expanded in spherical harmonics, until degree 24, and implemented in the code StagYY [Tackley, 2008] to perform mantle instantaneous flow modeling and compute surface topography and gravitational field. Our results show the importance of constraining the crustal and mantle density structure relying on a multidisciplinary approach that involves experimentally robust thermodynamic datasets. Crustal density field has a strong effect on the isostatic component of topography. The models that we test, CRUST 1.0 and those in Guerri and Cammarano [2015], produce strong differences in the computed isostatic topography, in the range ±600 m. For the lithospheric mantle, relying on experimentally robust material properties constraints is necessary to infer a reliable density model that takes into account chemical heterogeneities. This approach is also fundamental to correctly interpret seismic models in temperature, a crucial parameter, necessary to determine the lithosphere-asthenosphere boundary, where static effects on topography leave place to dynamic ones. The comparison between results obtained with different viscosity fields, either radially symmetric or vertically and laterally varying, shows how lateral viscosity variations affect the results, in particular the modeled geoid, at different wavelengths. References: Brocher, T. M. (2005), Empirical Relations between Elastic Wavespeeds and Density in the Earth's Crust, Bulletin of the Seismological Society of America, 95(6), 2081-2092. Cammarano, F., P. J. Tackley, and L. Boschi (2011), Seismic, petrological and geodynamical constraints on thermal and compositional structure of the upper mantle: global thermochemical models, Geophys. J. Int. Connolly, J. A. D. (2005), Computation of phase equilibria by linear programming: A

  15. Role of lime in salty spoil genesis

    SciTech Connect

    Grove, J.H.; Evangelou, V.P.

    1982-12-01

    Acid pyritic spoils are often limed to facilitate revegetation efforts. Substantial quantities of soluble sulfate salts are associated with such spoils, before and after liming. Such salts can cause revegetation attempts to fail at seeding and/or during drought stress periods. As magnesium sulfate (MgSO/sub 4/) is more soluble than gypsum (calcium sulfate) under field conditions, MgSO/sub 4/ has more often been associated with soluble salt problems. Since lime reaction chemistry can influence salt genesis in spoils, this was evaluated in a incubation study using calcite and dolomite amendments to an acid, pyritic spoil. Rates of 0, 14.4, and 28.8 meq/100 g (rate equal to total potential acidity) of lime were used. Amended spoils were maintained at 30/sup 0/C and -100 cm moisture tension. Samples were taken periodically and a portion suspended in water at a soil:solution ratio of 1:20 for two hours. Unamended spoil extract pH dropped from 4.8 to 3.2 in nine weeks. Soluble magnesium sulfate doubled (from 2.9 to 6.1 meq/100 g) in the unlimed spoil between weeks one and sixteen. Dolomite amended spoils generated twice as much magnesium salt as calcite amended spoils. Pyrite oxidation, acid generation, i.e., salt genesis, was reduced when calcitic lime was used at the recommended rate based on a measure of total potential acidity. A prompt liming program with calcitic lime can substantially alter the quantity and quality of soluble salts released. The results suggest that dolomite is unacceptable as a liming material for sandy spoils with an appreciable pyrite content.

  16. The Genesis Solar Wind Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Wiens, Roger C.; Burnett, Donald S.; Neugebauer, Marcia; Sasaki, Chester; Sevilla, Donald; Stansbery, Eileen; Clark, Ben; Smith, Nick; Oldham, Lloyd

    1990-01-01

    The Genesis spacecraft was launched on August 8 from Cape Canaveral on a journey to become the first spacecraft to return from interplanetary space. The fifth in NASA's line of low-cost Discovery-class missions, its goal is to collect samples of solar wind and return them to Earth for detailed isotopic and elemental analysis. The spacecraft is to collect solar wind for over two years, while circling the L1 point 1.5 million km sunward of the earth, before heading back for a capsule-style re-entry in September, 2004. After parachute deployment, a mid-air helicopter recovery will be used to avoid a hard landing. The mission has been in the planning stages for over ten years. Its cost, including development, mission operations, and sample analysis, is approximately $209M. The Genesis science team, headed by principal investigator Donald Burnett of Caltech, consists of approximately 20 co-investigators from universities and science centers around the country and internationally. The spacecraft consists of a relatively flat spacecraft bus containing most of the subsystem components, situated below a sample return capsule (SRC) which holds the solar-wind collection substrates and an electrostatic solar wind concentrator. Some of the collectors are exposed throughout the collection period, for a sample of bulk solar wind, while others are exposed only to certain solar wind regimes, or types of flow. Ion and electron spectrometers feed raw data to the spacecraft control and data-handling (C&DH) unit, which determines ion moments and electron flux geometries in real time. An algorithm is used to robotically decide between interstream (IS), coronal hole (CH), and coronal mass ejection (CME) regimes, and to control deployment of the proper arrays to sample these wind regimes independently. This is the first time such a solar-wind decision algorithm has been used on board a spacecraft.

  17. Aragats stratovolcano in Armenia - volcano-stratigraphy and petrology

    NASA Astrophysics Data System (ADS)

    Meliksetian, Khachatur; Savov, Ivan; Connor, Charles; Halama, Ralf; Jrbashyan, Ruben; Navasardyan, Gevorg; Ghukasyan, Yura; Gevorgyan, Hripsime; Manucharyan, Davit; Ishizuka, Osamu; Quidelleur, Xavier; Germa, Aurélie

    2014-05-01

    In this contribution we discuss the geological structure and volcano-stratigraphy of the Quaternary Aragats stratovolcano in Armenia based on recent age determinations as well as petrological and geochemical features of magma generation processes specific for collision zones. Armenia is situated in the NE part of the Anatolian-Armenian-Iranian plateau, an intensely deformed segment of the Alpine-Himalayan belt. The complex geological structure of the region is represented by a mosaic of tectonic blocks comprising fragments of volcanic arcs, continental crust and exhumed oceanic crust. Collision of the Arabian plate with the Eurasian margin in early Miocene resulted in orogenic uplift associated with intense volcanism. Aragats (4090m) is one the largest volcanoes in the entire region and produced central vent (inc. Plinian VEI>4) and monogenetic type flank eruptions and periphery plateaus within a total area greater than 5000 km2, known as Aragats volcanic province (AVP). The Aragats volcanic province (AVP) comprises the composite cone of Aragats volcano, the peak of which is built on a summit plateau, ~45 km in diameter shield structure with dozens of flank vents, scattered monogenetic cinder cones on the adjacent volcanic plateaus as well as the neighboring stratovolcano Arailer. New K-Ar and 40Ar/39Ar age determinations of groundmass and separated plagioclase samples indicate that volcanism at AVP began ~2.5 Ma, while most recent volcanic activity is 0.49 Ma for Plinian eruption of dacites from Irind flank vent and basaltic trachyandesite lava flows from Tirinkatar (0.48-0.61 Ma), Kakavasar, (0.52-0.54 Ma) and Ashtarak (0.58 Ma) monogenetic flank centers, as well as trachyandesites of Jrbazhan volcano on the summit plateau of Aragats (0.52 Ma). Based on bulk rock geochemical data (major, minor and low abundance trace elements, Sr and Nd isotopes) and mineral chemistry, we conclude that volcanic rocks of AVP are largely recording a complex mixing between deep

  18. GENESIS: GPS Environmental and Earth Science Information System

    NASA Technical Reports Server (NTRS)

    Hajj, George

    1999-01-01

    This presentation reviews the GPS ENvironmental and Earth Science Information System (GENESIS). The objectives of GENESIS are outlined (1) Data Archiving, searching and distribution for science data products derived from Space borne TurboRogue Space Receivers for GPS science and other ground based GPS receivers, (2) Data browsing using integrated visualization tools, (3) Interactive web/java-based data search and retrieval, (4) Data subscription service, (5) Data migration from existing GPS archived data, (6) On-line help and documentation, and (7) participation in the WP-ESIP federation. The presentation reviews the products and services of Genesis, and the technology behind the system.

  19. [The role of positive and negative angular accelerations in the genesis of early components of kinesthetic evoked potentials of the first somatosensory area in cats and rhesus monkeys].

    PubMed

    Fedan, V A

    1988-01-01

    Studies have been made on the input of negative and positive angular accelerations in the genesis of early complex of positive waves of kinesthetic evoked potentials in contralateral somatosensory cortex. It is suggested that the initial and final phases of these potentials play key role in the origin of the early complex of waves. PMID:3414221

  20. Magma Genesis in the Hawaiian Hot Spot: From melting experiments on basalt/peridotite hybrid source

    NASA Astrophysics Data System (ADS)

    Takahashi, E.

    2003-12-01

    Melting mantle peridotite is one of the central themes in experimental petrology. Melting studies in CMAS, NCMAS and natural peridotites have extensively documented the magma genesis process at Mid Oceanic Ridges (e.g., Presnall et al., 1979). Magma genesis in OIBs and LIPs, on the other hand, has been poorly constrained by experiments. Evidences from isotope geochemistry indicate that the source materials for basalt magmas in these provinces are not peridotite alone. Based on a geological and geochemical reconstruction of 3 Ma old Koolau volcano, I proposed that the size of eclogite blocks in the Hawaiian plume would exceed 1000km3 (Takahashi and Nakajima, 2002) and therefore the melting interaction of eclogite blocks and the surrounding peridotite would play essential roles in magma genesis in the Hawaiian hot spot. Melting experiments on basalt/peridotite composite starting materials were carried out at 2.5 to 3.0 GPa at temperatures from the peridotite dry solidus to that of basalt for 20 to 100 hours. Three layered starting materials consisting of 1 basalt to 2 peridotite (in volume) were placed in graphite/Pt double capsules. Peridotite KLB-1 (Fo89.6) and two basalt-starting materials (CLG-46 and CRB72-31) were used as starting materials. In temperatures ca.50-100 degrees below the peridotite solidus, silica-rich partial melts are produced in the basalt zone and the boundaries between the basalt and peridotite are coated with a 10 to 50 micron thick opx reaction band. The chemical reactions between the basalt and peridotite domains are controlled by solid diffusions across the opx reaction band and are very slow. In temperatures within 50 degrees of the peridotite dry solidus, a time dependent reaction process takes place. The basalt/peridotite boundary gradually partial melts as the chemical reaction lowers the peridotite solidus locally. At 2.8 GPa and 1450-1470C after 50-100 hours, resultant melt in the basalt layer becomes saturated with oliv + opx + cpx

  1. Nuts and Bolts — Techniques for Genesis Sample Curation

    NASA Astrophysics Data System (ADS)

    Burkett, P. J.; Rodriguez, M. C.; Allton, J. H.

    2011-03-01

    The Genesis curation staff at NASA JSC provides samples and data for analysis. We are showing: 1) techniques for characterization and measurement of shards; 2) allocation methods; and 3) status of the catalog by collector material, regime, and size.

  2. Genesis Spacecraft Science Canister Preliminary Inspection and Cleaning

    NASA Astrophysics Data System (ADS)

    Hittle, J. D.; Calaway, M. J.; Allton, J. H.; Warren, J. L.; Schwarz, C. M.; Stansbery, E. K.

    2006-03-01

    Inspection of the Genesis Science Canister revealed a micrometeorite impact, white paint discoloration, and black residue adhering to the structure. Loose particles were removed with a fine-haired brush and filter-trap vacuum.

  3. Apollo 14 Lunar glass fragment known as Genesis bean

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A tiny green glass fragment taken from an Apollo 14 core tube sampling. Because of its scientific significance and shape, the fragment has been nicknamed the 'Genesis bean'. The main constituents are iron and magnesium.

  4. The genesis of craniofacial biology as a health science discipline.

    PubMed

    Sperber, G H; Sperber, S M

    2014-06-01

    The craniofacial complex encapsulates the brain and contains the organs for key functions of the body, including sight, hearing and balance, smell, taste, respiration and mastication. All these systems are intimately integrated within the head. The combination of these diverse systems into a new field was dictated by the dental profession's desire for a research branch of basic science devoted and attuned to its specific needs. The traditional subjects of genetics, embryology, anatomy, physiology, biochemistry, dental materials, odontology, molecular biology and palaeoanthropology pertaining to dentistry have been drawn together by many newly emerging technologies. These new technologies include gene sequencing, CAT scanning, MRI imaging, laser scanning, image analysis, ultrasonography, spectroscopy and visualosonics. A vibrant unitary discipline of investigation, craniofacial biology, has emerged that builds on the original concept of 'oral biology' that began in the 1960s. This paper reviews some of the developments that have led to the genesis of craniofacial biology as a fully-fledged health science discipline of significance in the advancement of clinical dental practice. Some of the key figures and milestones in craniofacial biology are identified. PMID:24495071

  5. Lunar and Planetary Science XXXV: Martian Meteorites: Petrology

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Martian Meteorites: Petrology: included the following reports:Volatile Behavior in Lunar and Terrestrial Basalts During Shock: Implications for Martian Magmas; Problems with a Low-Pressure Tholeiitic Magmatic History for the Chassigny Dunite; Fast Cooling History of the Chassigny Martian Meteorite; Rehomogenized Interstitial and Inclusion Melts in Lherzolitic Shergottite ALH 77005: Petrologic Significance; Compositional Controls on the Formation of Kaersutite Amphibole in Shergottite Meteorites; Chemical Characteristics of an Olivine-Phyric Shergottite, Yamato 980459; Pb-Hf-Sr-Nd Isotopic Systematics and Age of Nakhlite NWA 998; Noble Gases in Two Samples of EETA 79001 (Lith. A); Experimental Constraints on the Iron Content of the Martian Mantle; and Mars as the Parent Body for the CI Carbonaceous Chondrites: New Data.

  6. Petrological evidence for secular cooling in mantle plumes.

    PubMed

    Herzberg, Claude; Gazel, Esteban

    2009-04-01

    Geological mapping and geochronological studies have shown much lower eruption rates for ocean island basalts (OIBs) in comparison with those of lavas from large igneous provinces (LIPs) such as oceanic plateaux and continental flood provinces. However, a quantitative petrological comparison has never been made between mantle source temperature and the extent of melting for OIB and LIP sources. Here we show that the MgO and FeO contents of Galapagos-related lavas and their primary magmas have decreased since the Cretaceous period. From petrological modelling, we infer that these changes reflect a cooling of the Galapagos mantle plume from a potential temperature of 1,560-1,620 degrees C in the Cretaceous to 1,500 degrees C at present. Iceland also exhibits secular cooling, in agreement with previous studies. Our work provides quantitative petrological evidence that, in general, mantle plumes for LIPs with Palaeocene-Permian ages were hotter and melted more extensively than plumes of more modern ocean islands. We interpret this to reflect episodic flow from lower-mantle domains that are lithologically and geochemically heterogeneous. PMID:19340079

  7. Exploration petrology of Sunoco Felda trend of south Florida

    SciTech Connect

    Mitchell-Tapping, H.

    1986-09-01

    The Sunoco Felda oil trend of the South Florida basin has been a prolific oil producer. All the oil is produced from the Cretaceous Sunniland formation, a leached limestone bioherm. Although the producing section has been considered reefal in the literature, petrographic and biostratigraphic analyses of various cores in producing fields have determined that these deposits are composed of particles of fragmented rudist and other fauna deposited in a tidal shoal. Atop this debris an algae and gastropod section has been deposited, typical of a mound deposited on a tidal mud flat. This model is exemplified in the Sunoco Felda and West Sunoco fields and was used in exploring the Sunoco Felda trend. From the petrological analysis of these two fields and from knowledge of other wells in the basin, biostratigraphic and lithologic trends can be determined and extended offshore into the eastern Gulf of Mexico. The author stresses petrology in exploring the Sunniland formation because correlating like responses on electric logs does not always result in correlating the same depositional facies - in fact, correlating like electric log responses in the Sunniland formation often results in correlating different facies. This study endeavors to analyze the Felda trend based on the petrological and petrophysical information obtained from the cores and logs. The author will show that the potential of the Sunniland formation may be greater than expected and that it may be the site of future major discoveries.

  8. On the genesis of the Haumea system

    NASA Astrophysics Data System (ADS)

    Campo Bagatin, A.; Benavidez, P. G.; Ortiz, J. L.; Gil-Hutton, R.

    2016-09-01

    The scenarios proposed in the literature for the genesis of the system formed by the dwarf planet 136108 Haumea, its two satellites and a group of some 10 bodies (the family) with semimajor axes, eccentricities and inclinations close to Haumea's values, are analysed against collisional, physical, dynamical and statistical arguments in order to assess their likelihood. All scenarios based on collisional events are reviewed under physical arguments and the corresponding formation probabilities in a collisional environment are evaluated according to the collisional evolution model ALICANDEP. An alternative mechanism is proposed based on the potential possibility of (quasi-) independent origin of the family with respect to Haumea and its satellites. As a general conclusion the formation of the Haumea system is a low-probability event in the currently assumed frame for the evolution of the outer Solar system. However, it is possible that current knowledge is missing some key element in the whole story that may contribute to increase the odds for the formation of such a system.

  9. Magnetic Investigations in the J-M Reef Section of the Stillwater Complex, Montana

    NASA Astrophysics Data System (ADS)

    Wnukowski, J. D.; Ferre, E. C.; Butak, K. C.

    2014-12-01

    The Stillwater J-M reef, the only economic platinum deposit in the USA, consists of a 0.5 to 4 m-thick stratiform zone of platinum group element (PGE)-rich sulfides in a layered mafic intrusion. The origin of this reef, purely magmatic or related to late-stage magmatic fluids, remains ambiguous. I propose to test these two genetic hypotheses using rock magnetism. Fractional crystallization trends deduced from petrological models would produce a sharp increase in magnetite and pyrrhotite content near the solidus. In contrast, percolation of sulfur-rich fluids through a crystal mush would produce a gradual increase in magnetite and pyrrhotite up to a fluid permeability barrier. Continuous logging of the magnetic properties of drillcores, combined with petrographic observations, will allow to test these two models. Petrologic similarities between PGE reefs suggest that they share common physico-chemical origins, therefore, understanding the J-M reef genesis would have implications for other deposits such as the Bushveld Complex and the Great Dyke of Zimbabwe. The J-M reef formation has been explained by two alternative models: 1) magmatic model - magma replenishment causes thermal convection at the interface between two magmas, inducing PGE leaching by a sulfur-saturated magma, followed by precipitation of sulfide droplets; 2) fluid fluxing model - a sulfur-rich residual, late magmatic fluid migrates upward through the crystal mush leading to PGE concentration along a magmatic permeability barrier against the hanging wall. Both models account for the majority of geochemical and petrological observations and may not be fundamentally mutually exclusive. However, understanding the origin of PGE reefs would certainly benefit from new approaches. Preliminary data shows systematic inch-scale cycling variations of magnetic susceptibility (Km) in the hanging-wall that supports the magmatic model. The discovery of this magnetic cyclicity matters because this core does not

  10. The Indus-Yarlung Zangbo (IYZ) ophiolites from Nanga Parbat to Namche Barwa syntaxes, Southern Tibet: First synthesis of the petrology, geochemistry and geochronology of the IYZ ophiolites, and implications for geodynamic reconstructions of Neo-Tethys

    NASA Astrophysics Data System (ADS)

    Hébert, Réjean; Bezard, Rachel; Guilmette, Carl; Dostal, Jaroslav; Wang, Chengshan; Liu, Zf

    2013-04-01

    The purpose of this first synthesis is to summarize findings on the Yarlung Zangbo Suture Zone (YZSZ) ophiolites in Southern Tibet, and to discuss some of thel remaining scientific problems. The YZSZ ophiolites have been studied for almost 30 years and constitute the youngest of the sutures recognized on the Tibet Plateau. It is now acknowledged the YZSZ is a complex assemblage of sedimentary, metamorphic and igneous rocks produced during and shortly after the collision between India and Eurasia. The ages of the various lithological units span a time interval from the Jurassic to the Middle Miocene, with some Permian and Devonian exotic blocks in the mélange zone. The YZSZ is characterized by ophiolitic complexes and an ophiolitic mélange. The ophiolites are of two types with complete and incomplete pseudostratigraphies. The complete sections, although tectonically reworked, are observed along the segment from Dazhuqu to Jiding in the Xigaze area and the Spontang ophiolite. The incomplete sequences are found in various locations, including Nidar, Kiogar, Jungbwa, Saga, Sangsang, Xigugabu, Luobusa. The incomplete nature of these ophiolites could be related to intraoceanic or orogenic/collisional origins. The YZSZ ophiolites are also distributed into two groups of ages: the Luobusa, Zedang and Kiogar sequences are Jurassic-Lower Cretaceous in age, whereas all other sequences are of a Lower Cretaceous age. Compilation of geochronological data suggest that some ophiolite sequences might have evolved for over more than 70 m.y. from their inital igneous genesis to obduction, which occurred around 70-90 Ma. Although the YZSZ ophiolites differ in terms of their petrological and geochemical characters, they were all generated in a suprasubduction zone setting, and more specifically in arc (few fore-arc) and back-arc environments. Our synthesis of ~500 geochemical analyses show variable mixing of components from N-MORB-type to IAT-CAB and to OIB end-members. The Jurassic

  11. Genesis of Microfracture Evolution in Epikarst

    NASA Astrophysics Data System (ADS)

    Dragila, M. I.; Hay, K.; Weisbrod, N.

    2014-12-01

    Evolution of the epikarst begins with the enlargement of micro-fractures. As hydraulic channels become connected to an exit system, the hydraulic gradient will drive continued development of primary karst channels. But, what is the genesis of micro-fracture evolution into channelized paths? We investigate two mechanisms and their role in the physical and chemical evolution of the microfracture. During liquid drainage, air-water interfacial instability leads to development of capillary droplets embedded in rock surface films. Pressure gradient between capillary droplets and rock surface films drives liquid into droplets via the matrix skin. Droplet paths may predispose the rock phase to greater dissolution relative to paths that experience only film flow. Successive droplets down the same path, as seen in experiments, could lead to linear erosional features that evolve toward pipe development. The rate of geochemical dissolution by these liquid elements depends upon fluid carrying capacity and dissolution kinetics. One of the mechanisms important to calcite dissolution is diffusion of CO2 from fracture air into the liquid elements. Exchange of fracture and atmospheric air can reset gas composition within the fracture system. A mechanism for regular flushing of microfracture air is suggested where nightly inverted thermal gradients in the upper 30 cm of rock near the rock-atmosphere interface, can trigger gas density instabilities within the microfracture that travel deeper into the epikarst, potentially flushing the entire microfracture system with atmospheric air. Such diurnal gas flushing would serve as a reset switch for microfracture-gas-chemistry towards atmospheric values on a daily basis. The net dissolution rate of microfractures, and the rate and spatial distribution of dissolved substances delivered to subsurface caverns, would depend on these two mechanisms of liquid motion and gas venting.

  12. Virtual petrological microscopy: web 2.0 technology for learning microscopy skills outside the laboratory

    NASA Astrophysics Data System (ADS)

    Kelley, S. P.; Whalley, P.; Tindle, A.

    2009-12-01

    Learning to use microscopes for geoscience or life science applications is a crucial part of the practical training offered in many science degrees, but the opportunities to study are often constrained by available laboratory space and time, and sometimes constrained by the number of high quality microscopes available. We will demonstrate a new based virtual petrological microscope which offers the opportunity for enhancement and enrichment of laboratory experience in geoscience. The focus of petrological microscope study is not primarily related to learning facts but is concerned with learning how to discriminate and classify within the paradigms of the discipline. In this case, the recognition and measurement of key features in rock samples in hand specimen and thin section. Whilst undertaking the practical exercise of recognition and naming of rock samples students are really being required to develop an understanding of the rock cycle as a model representing the relationship between rock categories and the process of their formation. The problems of teaching with complex visual materials, in effect of teaching learners 'how to see' from the scientific perspective of a particular discipline, are quite general. It could reasonably be expected that lessons learnt from the implementation and detailed evaluation of the proposed web-based system will generalise to many other topics in science education. Thus we focussed on the thin section images rather than reproducing a system that resembled a physical microscope. The virtual petrological microscope developed for a course at the Open University UK enables student acquisition of skills such as mineral and rock recognition using a browser window to explore thin sections of rocks as if they were using a laboratory microscope. The microscope allows students to pan around the thin sections (held as 1GB files on a remote server); zoom in and out, change from plane polarised light to cross polarised light conditions, and

  13. Petrological studies on the mantle peridotites recovered from the ocean floor in the western Pacific

    NASA Astrophysics Data System (ADS)

    Ishii, T.; Hirano, N.; Ohara, Y.; Bloomer, S.

    2006-12-01

    Geological and geophysical models for the various oceanic crusts (or lithosphere) have been proposed on the basis of the combined studies between seismic observation for the oceanic crusts and petrological models of the onland ophiolites, which have been assumed as fossil of oceanic crusts. It is very important to collect basement rocks constituting various oceanic crusts and to characterize those petrological features. Ocean floor is commonly covered by effusive volcanic rocks, however occasionally hypabyssal and plutonic rocks are observed among the unique geological environments in the Western Pacific as partly shown in the followings. VOLCANIC DIATREME(?): Very unique volcanic knolls have been recently discovered by N. Hirano at the typical oceanic crust in the Northwestern Pacific, off Tohoku of Northeastern Japan. The constituting rocks for the main volcanic edifice are porous alkaline lavas with 1-5Ma age containing abundant lithic fragments including gabbros as well as mantle peridotites. They are assumed as a volcanic diatreme induced in the Cretaceous oceanic lithosphere . Geological and petrological analyses on those volcano and volcanic rocks can make clear the geological cross (or columnar) section of the typical oceanic lithosphere including crust as well as upper mantle down to 100 km deep asthenospheric mantle. PARECE VERA BASIN: The Parece Vela Basin (PVB) is an extinct backarc basin in the Philippine Sea. The NNE extending escarpments and depressions (maximum depth 7500 m) are fossil fracture zones and extinct segmented spreading axes (first-order segments), respectively. Oceanic core complexes (OCCs), or megamullions, develop at each first-order segment. Recently discovered OCCs at slow-spreading ridges have been interpreted as exhumed footwalls of oceanic detachment faults in magma-starved ridge environments. Godzilla Mullion, one of the OCC in the PVR, is the worlds largest OCC, 10 times larger in area than the normal OCCs in the Mid

  14. Petrology, geochemistry, and tectonic implications of newly collected samples from Babeldaob Island, Republic of Palau

    NASA Astrophysics Data System (ADS)

    Reagan, M.; Ishizuka, O.; Hawkins, J.; Bloomer, S.; Fryer, P.; Ishii, T.; Kelley, K.; Kimura, J.; Michibayashi, K.; Ohara, Y.; Stern, R.; Blake, B.; Colin, P.; Colin, L.

    2006-12-01

    The islands of Palau in the Western Pacific mark the southern end of the Kyushu-Palau Ridge, which is the westernmost remnant arc of the Izu-Bonin-Mariana (IBM) system. Because it has extensive subaerial exposures of volcanic rocks, it offers an excellent opportunity for detailed geological and petrological investigation. The largest island of Palau, Babeldaob, is composed largely of volcanic materials erupted between the middle Eocene and Oligocene (Mason et al., 1956; Meijer et al., 1983; Cosca et al., 1998). Previous studies have been hampered by thick laterites but nevertheless have shown that boninites and more typical arc basalts and andesites make up these materials. These studies also suggest that early arc sequences similar to those identified along the IBM forearc to the north are also found here (Hawkins and Castillo, 1998). Road cutting and quarrying for the new "Compact Road" around Babeldaob have recently provided unprecedented exposures of the volcanic units. The scientific party for Cruise YK0612 of the R/V Yokosuka spent one day examining and sampling some of these outcrops. Here, we report geological impressions of these outcrops and preliminary petrological and geochemical data for these newly exposed volcanic rocks. The new outcrops expose volcanic conglomerates, breccias, and finer-grained sediments; lava flows, pillow lavas, dikes, and volcanic plugs. Some of the coarse sediments are massive and matrix- supported, and probably were deposited by debris flows. These are interbedded with normally graded turbidite sequences, suggesting subaqueous deposition. A quarry near the east-central coast exposed a complex of meter-scale dikes cut by fault gouge zones. Shallow dome and breccia deposits as well as a pillow lava sequence cropped out in a quarry and a road-cut respectively along the central spine of the island. Most samples are broadly basaltic to andesitic and boninitic, although hornblende andesites or dacites compose the dome and one section

  15. Innovative genomic collaboration using the GENESIS (GEM.app) platform.

    PubMed

    Gonzalez, Michael; Falk, Marni J; Gai, Xiaowu; Postrel, Richard; Schüle, Rebecca; Zuchner, Stephan

    2015-10-01

    Next-generation sequencing has led to an unparalleled pace of Mendelian disease gene discovery in recent years. To address the challenges of analysis and sharing of large datasets, we had previously introduced the collaborative web-based GEM.app software [Gonzalez et al., ]. Here, we are presenting the results of using GEM.app over nearly 3 years and introducing the next generation of this platform. First, GEM.app has been renamed to GENESIS since it is now part of "The Genesis Project" (501c3), a not-for-profit foundation that is committed to providing the best technology to enable research scientists and to connecting patients and clinicians to genomic information. Second, GENESIS (GEM.app) has grown to nearly 600 registered users from 44 countries, who have collectively achieved 62 gene identifications or published studies that have expanded phenotype/genotype correlations. Our concept of user-driven data sharing and matchmaking is now the main cause for gene discoveries within GENESIS. In many of these findings, researchers from across the globe have been connected, which gave rise to the genetic evidence needed to successfully pinpoint-specific gene mutations that explained patients' disease. Here, we present an overview of the various novel insights that have been made possible through the data-sharing capabilities of GENESIS/GEM.app. PMID:26173844

  16. Petrological Investigations of CAIs from Efremovka and NWA 3118 CV3 Chondrites

    NASA Astrophysics Data System (ADS)

    Ivanova, M. A.; Lorenz, C. A.; Korochantseva, E. V.; MacPherson, G. J.

    2010-03-01

    Several new big CAIs were extracted from the Efremovka and NWA 3118 CV3 chondrites to analyze petrology, chemistry and isotopic compositions. Here we report preliminary results on mineralogy, petrology and bulk chemistry of two CAIs, of Type B1 and of Type A.

  17. Cosmological matching conditions and galilean genesis in Horndeski's theory

    SciTech Connect

    Nishi, Sakine; Kobayashi, Tsutomu; Tanahashi, Norihiro; Yamaguchi, Masahide E-mail: tsutomu@rikkyo.ac.jp E-mail: gucci@phys.titech.ac.jp

    2014-03-01

    We derive the cosmological matching conditions for the homogeneous and isotropic background and for linear perturbations in Horndeski's most general second-order scalar-tensor theory. In general relativity, the matching is done in such a way that the extrinsic curvature is continuous across the transition hypersurface. This procedure is generalized so as to incorporate the mixing of scalar and gravity kinetic terms in the field equations of Horndeski's theory. Our matching conditions have a wide range of applications including the galilean genesis and the bounce scenarios, in which stable, null energy condition violating solutions play a central role. We demonstrate how our matching conditions are used in the galilean genesis scenario. In doing so, we extend the previous genesis models and provide a unified description of the theory admitting the solution that starts expanding from the Minkowski spacetime.

  18. Investigation of Backside Textures for Genesis Solar Wind Silicon Collectors

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. P.; Burkett, P. J.; Rodriguez, M. C.; Allton, J. H.

    2014-01-01

    Genesis solar wind collectors were comprised of a suite of 15 types of ultrapure materials. The single crystal, pure silicon collectors were fabricated by two methods: float zone (FZ) and Czochralski (CZ). Because of slight differences in bulk purity and surface cleanliness among the fabrication processes and the specific vendor, it is desirable to know which variety of silicon and identity of vendor, so that appropriate reference materials can be used. The Czochralski method results in a bulk composition with slightly higher oxygen, for example. The CZ silicon array wafers that were Genesis-flown were purchased from MEMC Electronics. Most of the Genesis-flown FZ silicon was purchased from Unisil and cleaned by MEMC, although a few FZ wafers were acquired from International Wafer Service (IWS).

  19. Petrogenesis of the Main Petrologic and Chronologic Volcanic Phases in the Gharyan Province, NW Libya.

    NASA Astrophysics Data System (ADS)

    Gafeer, A.; Nabelek, P. I.

    2014-12-01

    Cenozoic Libyan volcanic fields are manifestations of tremendous episodic outpourings of basaltic lavas within the East Saharan Craton. The volcanic fields are confined to a NW-SE trend (N140°E) that stretches from the Mediterranean coast in the north to Tibesti (Libya-Chad border) in the south. The four major volcanic fields (Gharyan, As-Sawda, Al-Haruj, and Nuquay) show a systematic decrease in age starting from ~55 Ma in Gharyan (NW) to the Holocene in Nuquay (SE). This apparent trend in ages along with characteristics resembling oceanic island basalts (OIB's) prompted several authors to attribute their origin to the African plate moving over a hot spot (e.g. Conticelli et al. 1995; Woller and Fediuk 1980; Hegazy 1999). In the Gharyan province (GVP), the igneous activity was indeed episodic and lasted for at least 50 Ma. The large span of ages of these volcanic rocks within the same volcanic field makes the hot spot model at least equivocal. Whole rock analyses for the major petrologic and chronologic units suggest that the basaltic and phonolitic suites within the GVP had different primary sources. The basaltic rocks show smooth REE patterns. LREE/HREE fractionations of the eruptive pulses are inconsistent with their ages, suggesting that they represent different melt fractions generated from the same mantle source. Phonolites show very different REE patterns. The patterns are concave-upward with low TbN/YbN ratios (0.6-0.8). The origin of the GVP basaltic rocks is consistent with melts generated from metasomatized lithospheric mantle across the garnet-spinel transition zone. The most primitive (>7 wt % MgO) basalts were used to model mantle melting processes and indicate 3-10% melting of an amphibole-bearing, spinel/garnet mantle source. Rather than being related to a hot spot, the genesis of the Libyan lavas appears to have been caused by reactivation of lithospheric megastructures with asthenospheric upwelling, in relation to the Africa-Europe convergence.

  20. Linking petrology and seismology of the southwest Greenland lithosphere

    NASA Astrophysics Data System (ADS)

    Lesher, C. E.; Vestergaard, C.; Brown, E.; Schutt, D.

    2015-12-01

    Mantle xenoliths from late-Proterozoic diamond-bearing kimberlitic dikes in the Kangerlussuaq, Sarfartoq and Maniitsoq areas of southwestern Greenland provide constraints on the composition and thermal state of lithospheric mantle beneath Greenland to depths of ~200 km [1]. Similarly, surface wave tomography studies carried out as part of the GLATIS project use a range of Rayleigh wave periods sensitive to structures at a similar depth interval within southwestern Greenland lithospheric mantle [2]. Here we link petrologic and seismologic constraints on the mantle lithosphere beneath Greenland utilizing methods of [3] that show that inferred chemical and mineralogical stratification inferred from petrology, showing mantle peridotite transitioning from garnet-free harzburgite to garnet lherzolite between ~70 and 180 km, cannot readily be resolved with fundamental mode Rayleigh waves. On the other hand, comparing phase velocities predicted from xenolith compositions, mineralogy and last equilibration temperatures and pressures, defining the continental geotherm during late-Proterozoic time, with those for the present-day mantle lithosphere suggest significant cooling of the cratonic mantle to a modern geotherm characterized by a heat flux of 30 mW/m2 and average crustal heat production of 0.3 mW/m3 [4]. These preliminary findings point to the weak dependence of shear wave velocities on mantle peridotite composition and mineralogy, and further illustrate its strong temperature dependence. Comparison of ancient and modern continental geotherms made possible by combining petrologic and seismological data, as shown here for southwest Greenland, provide additional constraints on secular cooling of cratonic regions linked to large-scale tectonic processes. [1] Bizzarro et al., 2003, CMP, 146; Sand et al., Lithos, 112. [2] Darbyshire et al., 2004, GJI, 158. [3] Schutt and Lesher, 2006, JGR, 111. [4] Meirerbachtol et al., 2015, JGR/ES, 120.

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

    NASA Astrophysics Data System (ADS)

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

    1994-07-01

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

  2. Geochemical and petrological observations of gas transport at arc volcanoes

    NASA Astrophysics Data System (ADS)

    Edmonds, M.; Herd, R. A.; Humphreys, M.; Aiuppa, A.; Giudice, G.; Guida, R.; Moretti, R.; Christopher, T. E.; Rawson, H.

    2010-12-01

    Understanding the abundance and composition of vapour in magma chambers and the mechanisms of vapour transport in volcanic systems is of immense importance. Exsolved vapour in a magma storage area affects eruption style and duration, and influences ground deformation and other geophysical manifestations owing to its compressibility. Ultimately, we wish to understand how much pre-eruptive exsolved vapour exists and what role mafic magma supply at depth plays in supplying it. Soufriere Hills Volcano, Montserrat, has become an exceptionally well-monitored volcanic system and there is now an abundance of detailed geochemical and petrological information regarding magma degassing and gas transport processes. The eruption provides a unique opportunity to study the effects of open system mafic magma injection, mingling and degassing, which is occurring on the same time scale as eruption. We examine the geochemical and petrological evidence for magma mingling, degassing and gas fluxing at Soufriere Hills Volcano. We use measurements of gas flux and composition, using DOAS and a multigas sensor. We examine petrological and textural evidence for mafic magma supplying volatiles to the system, including evidence from phenocryst zoning and composition. We show that the mafic magma supplies volatiles as well as heat to the overlying resident andesite. Due to the strong partitioning of sulphur into a vapour phase at depth under oxidising conditions, the sulphur dissolved in the intruding mafic magma becomes segregated into vapour, along with carbon dioxide and water. The vapour is transported to the surface during both eruptive and non-eruptive periods, implying either that significant permeability exists within the system, or that magma convection operates. There is some evidence for gas fluxing, which suggests that gas may be transported through the magma. We draw comparisons with other recent studies of volatile transport in arc systems to show that some observations may be

  3. Learning Mathematics in a CAS Environment: The Genesis of a Reflection about Instrumentation and the Dialectics between Technical and Conceptual Work.

    ERIC Educational Resources Information Center

    Artigue, Michele

    2002-01-01

    Presents an anthropological approach used in French research and the theory of instrumentation developed in cognitive ergonomics. Shows how these frameworks allow an approach to the educational use of CAS technology, focusing on the unexpected complexity of instrumental genesis, mathematical needs of instrumentation, status of instrumented…

  4. Petrology and stratigraphy of Paleogene nonmarine sandstones, Cascade Range, Washington

    USGS Publications Warehouse

    Frizzell, Virgil A.

    1979-01-01

    The Cascade Range of Washington north of 47? latitude is composed of probable Paleozoic and Mesozoic metamorphic rocks and Mesozoic and Tertiary plutonic rocks. Several Paleogene nonmarine arkosic sandstone units fringe and in part occur within the complex crystalline core. The early to middle Eocene Chuckanut Formation is present on the west side of the crystalline core in the western foothills of the Cascades. The early to middle Eocene Swauk Formation partially encircles the Mt. Stuart massif of the central Cascades. In the western foothills of the Cascades, between the main body of Chuckanut Formation near Bellingham and the main outcrop area of the Swauk Formation south of Mt. Stuart, many smaller bodies of arkosic sandstone have variously been referred to either the Swauk or Chuckanut Formations. The early Eocene Manastash Formation occurs locally in an area south of the Yakima River. The middle to late Eocene Chumstick Formation is mostly confined to the Chiwaukum graben within the crystalline core and is separated from the Swauk Formation on the southwest by the Leavenworth Fault. The Oligocene Wenatchee Formation unconformably over lies the Chumstick Formation near Wenatchee. The middle to late Eocene Roslyn Formation crops out north of the Yakima River and is underlain by the Teanaway Basalt which separates the Roslyn from the older Swauk Formation. The middle Eocene to early Oligocene Naches Formation forms a north-trending body that crosses the Yakima River and is in fault contact with both the Swauk and Manastash Formations. The middle to late Eocene Puget Group underlies the Quaternary deposits of the Puget Lowland southeast of Seattle on the western flank of the Cascades. The various formations are all composed predominantly of fine- to medium-grained sandstones with lesser amounts of interbedded shale, conglomerate and coal. Compositionally, the units are predominantly either feldspathic or litho-feldspathic subquartzose sandstones. Volcanic rocks

  5. Petrology and classification of the Garraf, Spain chondrite

    NASA Technical Reports Server (NTRS)

    Keil, K.; Conrad, G. H.; King, E. A.; San Miguel, A.

    1986-01-01

    Microscopic and electron microprobe studies indicate that the Garraf meteorite is a highly-recrystallized chondrite of petrologic type 6. Olivine (Fa24.7; PMD 1.1) and low-Ca pyroxene (Fs20.9; PMD 1.1) compositions indicate that it belongs to the L-group. Based on contents of noble gases, pervasive fracturing of silicates, common undulose extinction of olivine and plagioclase, and the lack of melt pockets and maskelynite, Garraf is placed into shock facies b. It is concluded that Garraf is a highly recrystallized L6b chondrite that, after recrystallization, was cataclased and comminuted by shock.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  7. The mineralogy and petrology of the Luna 20 soil sample.

    NASA Technical Reports Server (NTRS)

    Kridelbaugh, S. J.; Weill, D. F.

    1973-01-01

    The lithologic types found in the soil at the Luna site are characterized, and their mineralogical and petrological significance is discussed. Chemically, the Luna 20 and Apollo 16 soil samples are similar, but the Luna 20 soil is slightly depleted in aluminum and calcium and enriched in iron and magnesium relative to the Apollo 16 soils. This slight difference may be a result of the presence of a minor amount of mare material in the Luna 20 soil and its apparent absence in the Apollo 16 soils.

  8. Mineralogy and Petrology of COMET WILD2 Nucleus Samples

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael; Bland, Phil; Bradley, John; Brearley, Adrian; Brennan, Sean; Bridges, John; Brownlee, Donald; Butterworth, Anna; Dai, Zurong; Ebel, Denton

    2006-01-01

    The sample return capsule of the Stardust spacecraft will be recovered in northern Utah on January 15, 2006, and under nominal conditions it will be delivered to the new Stardust Curation Laboratory at the Johnson Space Center two days later. Within the first week we plan to begin the harvesting of aerogel cells, and the comet nucleus samples they contain for detailed analysis. By the time of the LPSC meeting we will have been analyzing selected removed grains for more than one month. This presentation will present the first results from the mineralogical and petrological analyses that will have been performed.

  9. Petrology and classification of the Garraf, Spain chondrite

    NASA Astrophysics Data System (ADS)

    Keil, K.; Conrad, G. H.; King, E. A.; San Miguel, A.

    1986-03-01

    Microscopic and electron microprobe studies indicate that the Garraf meteorite is a highly-recrystallized chondrite of petrologic type 6. Olivine (Fa24.7; PMD 1.1) and low-Ca pyroxene (Fs20.9; PMD 1.1) compositions indicate that it belongs to the L-group. Based on contents of noble gases, pervasive fracturing of silicates, common undulose extinction of olivine and plagioclase, and the lack of melt pockets and maskelynite, Garraf is placed into shock facies b. It is concluded that Garraf is a highly recrystallized L6b chondrite that, after recrystallization, was cataclased and comminuted by shock.

  10. Silicate-melt inclusions in magmatic rocks: applications to petrology

    NASA Astrophysics Data System (ADS)

    Frezzotti, Maria-Luce

    2001-01-01

    Silicate-melt inclusions in igneous rocks provide important information on the composition and evolution of magmatic systems. Such inclusions represent accidentally trapped silicate melt (±immiscible H 2O and/or CO 2 fluids) that allow one to follow the evolution of magmas through snapshots, corresponding to specific evolution steps. This information is available on condition that they remained isolated from the enclosing magma after their entrapment. The following steps of investigation are discussed: (a) detailed petrographic studies to characterise silicate-melt inclusion primary characters and posttrapping evolution, including melt crystallisation; (b) high temperature studies to rehomogenise the inclusion content and select chemically representative inclusions: chemical compositions should be compared to relevant phase diagrams. Silicate-melt inclusion studies allow us to concentrate on specific topics; inclusion studies in early crystallising phases allow the characterisation of primary magmas, while in more differentiated rocks, they unravel the subsequent chemical evolution. The distribution of volatile species (i.e., H 2O, CO 2, S, Cl) in inclusion glass can provide information on the degassing processes and on recycling of subducted material. In intrusive rocks, silicate melt inclusions may preserve direct evidence of magmatic stage evolution (e.g., immiscibility phenomena). Melt inclusions in mantle xenoliths indicate that high-silica melts can coexist with mantle peridotites and give information on the presence of carbonate melt within the upper mantle. Thus, combining silicate-melt inclusion data with conventional petrological and geochemical information and experimental petrology can increase our ability to model magmatic processes.

  11. Geochemistry of Martian Meteorites and the Petrologic Evolution of Mars

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.

    2002-01-01

    Mafic igneous rocks serve as probes of the interiors of their parent bodies - the compositions of the magmas contain an imprint of the source region composition and mineralogy, the melting and crystallization processes, and mixing and assimilation. Although complicated by their multifarious history, it is possible to constrain the petrologic evolution of an igneous province through compositional study of the rocks. Incompatible trace elements provide one means of doing this. I will use incompatible element ratios of martian meteorites to constrain the early petrologic evolution of Mars. Incompatible elements are strongly partitioned into the melt phase during igneous processes. The degree of incompatibility will differ depending on the mineral phases in equilibrium with the melt. Most martian meteorites contain some cumulus grains, but nevertheless, incompatible element ratios of bulk meteorites will be close to those of their parent magmas. ALH 84001 is an exception, and it will not be discussed. The martian meteorites will be considered in two groups; a 1.3 Ga group composed of the clinopyroxenites and dunite, and a younger group composed of all others.

  12. 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.

  13. 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.

  14. Towards Predictive Stochastic Dynamical Modeling of Cancer Genesis and Progression

    PubMed Central

    Ao, P.; Galas, D.; Hood, L.; Yin, L.; Zhu, X.M.

    2011-01-01

    Based on an innovative endogenous network hypothesis on cancer genesis and progression we have been working towards a quantitative cancer theory along the systems biology perspective. Here we give a brief report on our progress and illustrate that combing ideas from evolutionary and molecular biology, mathematics, engineering, and physics, such quantitative approach is feasible. PMID:20640781

  15. Genesis Solar Wind Collector Cleaning Assessment: 60366 Sample Case Study

    NASA Technical Reports Server (NTRS)

    Goreva, Y. S.; Gonzalez, C. P.; Kuhlman, K. R.; Burnett, D. S.; Woolum, D.; Jurewicz, A. J.; Allton, J. H.; Rodriguez, M. C.; Burkett, P. J.

    2014-01-01

    In order to recognize, localize, characterize and remove particle and thin film surface contamination, a small subset of Genesis mission collector fragments are being subjected to extensive study via various techniques [1-5]. Here we present preliminary results for sample 60336, a Czochralski silicon (Si-CZ) based wafer from the bulk array (B/C).

  16. Genesis Solar-Wind Sample Return Mission: The Materials

    NASA Technical Reports Server (NTRS)

    Jurewicz, A. J. G.; Burnett, D. S.; Wiens, R. C.; Woolum, D.

    2000-01-01

    This abstract is a brief overview of the Genesis mission. Included is an instrument description, what materials were chosen for capturing solar wind and why, and information as to what will be available for analysis when the samples return to Earth in 2003.

  17. Small Particulate Contamination Survey Of Genesis Flight Sample 61423

    NASA Technical Reports Server (NTRS)

    Kuhlman, K. R.; Schmeling, M.; Gonzalez, C. P.; Allums, K. K.; Allton, J. H.; Burnett, D. S.

    2016-01-01

    The Genesis mission collected solar wind and brought it back to Earth in order to provide precise knowledge of solar isotopic and elemental compositions. The ions in the solar wind stop in the collectors at depths on the order of 10 to a few hundred nanometers. This shallow implantation layer is critical for scientific analysis of the composition of the solar wind and must be preserved throughout sample handling, cleaning, processing, distribution, preparation and analysis. We continue to work with the community of scientists analyzing Genesis samples using our unique laboratory facilities -- and, where needed, our unique cleaning techniques -- to significantly enhance the science return from the Genesis mission. This work is motivated by the need to understand the submicron contamination on the collectors in the Genesis payload as recovered from the crash site in the Utah desert, and -- perhaps more importantly -- how to remove it. We continue to evaluate the effectiveness of the wet-chemical "cleaning" steps used by various investigators, to enable them to design improved methods of stripping spacecraft and terrestrial contamination from surfaces while still leaving the solar-wind signal intact.

  18. Decontamination of Genesis Array Materials by UV Ozone Cleaning

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Burnett, D. S.; Rodriquez, M. C.; Sestak, S.; Allton, J. H.; Stansbery, E. K.

    2007-01-01

    Shortly after the NASA Genesis Mission sample return capsule returned to earth on September 8, 2004, the science team discovered that all nine ultra-pure semiconductor materials were contaminated with a thin molecular organic film approximately 0 to 100 angstroms thick. The organic contaminate layer, possibly a silicone, situated on the surface of the materials is speculated to have formed by condensation of organic matter from spacecraft off-gassing at the Lagrange 1 halo orbit during times of solar exposure. While the valuable solar wind atoms are safely secured directly below this organic contamination and/or native oxide layer in approximately the first 1000 angstroms of the ultra-pure material substrate, some analytical techniques that precisely measure solar wind elemental abundances require the removal of this organic contaminate. In 2005, Genesis science team laboratories began to develop various methods for removing the organic thin film without removing the precious material substrate that contained the solar wind atoms. Stephen Sestak and colleagues at Open University first experimented with ultraviolet radiation ozone (UV/O3) cleaning of several non-flight and flown Genesis silicon wafer fragments under a pure flowing oxygen environment. The UV/O3 technique was able to successfully remove organic contamination without etching into the bulk material substrate. At NASA Johnson Space Center Genesis Curation Laboratory, we have installed an UV/O3 cleaning devise in an ambient air environment to further experimentally test the removal of the organic contamination on Genesis wafer materials. Preliminary results from XPS analysis show that the UV/O3 cleaning instrument is a good non-destructive method for removing carbon contamination from flown Genesis array samples. However, spectroscopic ellipsometry results show little change in the thickness of the surface film. All experiments to date have shown UV/O3 cleaning method to be the best non-destructive method

  19. Ab initio modelling: Genesis of crystal structures

    NASA Astrophysics Data System (ADS)

    van de Walle, Axel

    2005-05-01

    Genetic algorithms prove useful to distil a complex quantum mechanical calculation of interatomic interactions down to its simplest mathematical expression. This makes it possible to predict the structure of new compounds from first principles.

  20. Geochemical and petrological study of Barberton Greenstone Belt cherts (3.2-3.5 Ga), South Africa

    NASA Astrophysics Data System (ADS)

    Ledevin, M.; Arndt, N.; Simionovici, A.

    2011-12-01

    The massive deposition of cherts during Archean time provides important information about conditions on the sea floor during the early history of the Earth. We studied samples from four sites in the Barberton Greenstone Belt (3.2-3.5 Ga), South Africa, including fresh ICDP core samples, to understand their formation. We identified three different origins for cherts: direct precipitation from seawater, precipitation in fractures from silica-rich fluids, and replacement of preexisting rocks (silicification) at or near the surface. To better constrain the various formation processes of cherts, we use a petrological, rheological and geochemical approach: both macro- and micro- structural observations are used to understand early physical behavior of chert, silica precipitation, and silicification processes. Rheological information is obtained by careful field observations: we observe a complex behavior for cherts, with ductile to brittle deformation structures, sometimes both in the same layer, extremely fast diagenetic induration processes, and evidence of an early colloidal silica phase. High-resolution analyses (RAMAN, synchrotron and lab-based X-Ray microfluorescence, cathodoluminescence) are used to link micro-scale element distribution with microstructures, and to understand micro-scale formation processes. These approaches will be complemented by stable isotope (Si and O) and fluid inclusions analyses. Coupling petrological informations and geochemical analyses allow us to define reliable criteria to differentiate the three origins of cherts. When petrological observations show a secondary silicification of previously deposited sediments (e.g. laminations, ripple marks, silicified ashes), samples have trace element patterns with high HREE contents, and strong negative Sr and Li anomalies. In comparison, when cherts seem to be chemically precipitated on the sea floor, patterns show lower HREE and higher LILE contents, with a strong positive Ba anomaly and

  1. Python as a federation tool for GENESIS 3.0.

    PubMed

    Cornelis, Hugo; Rodriguez, Armando L; Coop, Allan D; Bower, James M

    2012-01-01

    The GENESIS simulation platform was one of the first broad-scale modeling systems in computational biology to encourage modelers to develop and share model features and components. Supported by a large developer community, it participated in innovative simulator technologies such as benchmarking, parallelization, and declarative model specification and was the first neural simulator to define bindings for the Python scripting language. An important feature of the latest version of GENESIS is that it decomposes into self-contained software components complying with the Computational Biology Initiative federated software architecture. This architecture allows separate scripting bindings to be defined for different necessary components of the simulator, e.g., the mathematical solvers and graphical user interface. Python is a scripting language that provides rich sets of freely available open source libraries. With clean dynamic object-oriented designs, they produce highly readable code and are widely employed in specialized areas of software component integration. We employ a simplified wrapper and interface generator to examine an application programming interface and make it available to a given scripting language. This allows independent software components to be 'glued' together and connected to external libraries and applications from user-defined Python or Perl scripts. We illustrate our approach with three examples of Python scripting. (1) Generate and run a simple single-compartment model neuron connected to a stand-alone mathematical solver. (2) Interface a mathematical solver with GENESIS 3.0 to explore a neuron morphology from either an interactive command-line or graphical user interface. (3) Apply scripting bindings to connect the GENESIS 3.0 simulator to external graphical libraries and an open source three dimensional content creation suite that supports visualization of models based on electron microscopy and their conversion to computational models

  2. Python as a Federation Tool for GENESIS 3.0

    PubMed Central

    Cornelis, Hugo; Rodriguez, Armando L.; Coop, Allan D.; Bower, James M.

    2012-01-01

    The GENESIS simulation platform was one of the first broad-scale modeling systems in computational biology to encourage modelers to develop and share model features and components. Supported by a large developer community, it participated in innovative simulator technologies such as benchmarking, parallelization, and declarative model specification and was the first neural simulator to define bindings for the Python scripting language. An important feature of the latest version of GENESIS is that it decomposes into self-contained software components complying with the Computational Biology Initiative federated software architecture. This architecture allows separate scripting bindings to be defined for different necessary components of the simulator, e.g., the mathematical solvers and graphical user interface. Python is a scripting language that provides rich sets of freely available open source libraries. With clean dynamic object-oriented designs, they produce highly readable code and are widely employed in specialized areas of software component integration. We employ a simplified wrapper and interface generator to examine an application programming interface and make it available to a given scripting language. This allows independent software components to be ‘glued’ together and connected to external libraries and applications from user-defined Python or Perl scripts. We illustrate our approach with three examples of Python scripting. (1) Generate and run a simple single-compartment model neuron connected to a stand-alone mathematical solver. (2) Interface a mathematical solver with GENESIS 3.0 to explore a neuron morphology from either an interactive command-line or graphical user interface. (3) Apply scripting bindings to connect the GENESIS 3.0 simulator to external graphical libraries and an open source three dimensional content creation suite that supports visualization of models based on electron microscopy and their conversion to computational

  3. A Magnetic Petrology Database for Satellite Magnetic Anomaly Interpretations

    NASA Astrophysics Data System (ADS)

    Nazarova, K.; Wasilewski, P.; Didenko, A.; Genshaft, Y.; Pashkevich, I.

    2002-05-01

    A Magnetic Petrology Database (MPDB) is now being compiled at NASA/Goddard Space Flight Center in cooperation with Russian and Ukrainian Institutions. The purpose of this database is to provide the geomagnetic community with a comprehensive and user-friendly method of accessing magnetic petrology data via Internet for more realistic interpretation of satellite magnetic anomalies. Magnetic Petrology Data had been accumulated in NASA/Goddard Space Flight Center, United Institute of Physics of the Earth (Russia) and Institute of Geophysics (Ukraine) over several decades and now consists of many thousands of records of data in our archives. The MPDB was, and continues to be in big demand especially since recent launching in near Earth orbit of the mini-constellation of three satellites - Oersted (in 1999), Champ (in 2000), and SAC-C (in 2000) which will provide lithospheric magnetic maps with better spatial and amplitude resolution (about 1 nT). The MPDB is focused on lower crustal and upper mantle rocks and will include data on mantle xenoliths, serpentinized ultramafic rocks, granulites, iron quartzites and rocks from Archean-Proterozoic metamorphic sequences from all around the world. A substantial amount of data is coming from the area of unique Kursk Magnetic Anomaly and Kola Deep Borehole (which recovered 12 km of continental crust). A prototype MPDB can be found on the Geodynamics Branch web server of Goddard Space Flight Center at http://core2.gsfc.nasa.gov/terr_mag/magnpetr.html. The MPDB employs a searchable relational design and consists of 7 interrelated tables. The schema of database is shown at http://core2.gsfc.nasa.gov/terr_mag/doc.html. MySQL database server was utilized to implement MPDB. The SQL (Structured Query Language) is used to query the database. To present the results of queries on WEB and for WEB programming we utilized PHP scripting language and CGI scripts. The prototype MPDB is designed to search database by major satellite magnetic

  4. Teaching Igneous and Metamorphic Petrology Through Guided Inquiry Projects

    NASA Astrophysics Data System (ADS)

    McMillan, N. J.

    2003-12-01

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

  5. Semantically Enabling Knowledge Representation of Metamorphic Petrology Data

    NASA Astrophysics Data System (ADS)

    West, P.; Fox, P. A.; Spear, F. S.; Adali, S.; Nguyen, C.; Hallett, B. W.; Horkley, L. K.

    2012-12-01

    More and more metamorphic petrology data is being collected around the world, and is now being organized together into different virtual data portals by means of virtual organizations. For example, there is the virtual data portal Petrological Database (PetDB, http://www.petdb.org) of the Ocean Floor that is organizing scientific information about geochemical data of ocean floor igneous and metamorphic rocks; and also The Metamorphic Petrology Database (MetPetDB, http://metpetdb.rpi.edu) that is being created by a global community of metamorphic petrologists in collaboration with software engineers and data managers at Rensselaer Polytechnic Institute. The current focus is to provide the ability for scientists and researchers to register their data and search the databases for information regarding sample collections. What we present here is the next step in evolution of the MetPetDB portal, utilizing semantically enabled features such as discovery, data casting, faceted search, knowledge representation, and linked data as well as organizing information about the community and collaboration within the virtual community itself. We take the information that is currently represented in a relational database and make it available through web services, SPARQL endpoints, semantic and triple-stores where inferencing is enabled. We will be leveraging research that has taken place in virtual observatories, such as the Virtual Solar Terrestrial Observatory (VSTO) and the Biological and Chemical Oceanography Data Management Office (BCO-DMO); vocabulary work done in various communities such as Observations and Measurements (ISO 19156), FOAF (Friend of a Friend), Bibo (Bibliography Ontology), and domain specific ontologies; enabling provenance traces of samples and subsamples using the different provenance ontologies; and providing the much needed linking of data from the various research organizations into a common, collaborative virtual observatory. In addition to better

  6. Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).

    PubMed

    Lemloh, Marie-Louise; Marin, Frédéric; Herbst, Frédéric; Plasseraud, Laurent; Schweikert, Michael; Baier, Johannes; Bill, Joachim; Brümmer, Franz

    2013-02-01

    In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, energy-dispersive X-ray spectroscopy, FTIR and X-ray diffraction. Our investigations revealed an organic mesh-like structure that guides the formation of new alveolar plates like a template and the role of vesicles transporting inorganic material. We further demonstrated that the inorganic part of the alveolar plates is composed out of amorphous calcium carbonate. For stabilization of the amorphous phase, the alveolar vesicles, the organic fraction and the element phosphorus may play a role. PMID:23228488

  7. JPL Genesis and Rapid Intensification Processes (GRIP) Portal

    NASA Technical Reports Server (NTRS)

    Knosp, Brian W.; Li, P. Peggy; Vu, Quoc A.; Turk, Francis J.; Shen, Tsae-Pyng J.; Hristova-Veleva, Svetla M.; Licata, Stephen J.; Poulsen, William L.

    2012-01-01

    Satellite observations can play a very important role in airborne field campaigns, since they provide a comprehensive description of the environment that is essential for the experiment design, flight planning, and post-experiment scientific data analysis. In the past, it has been difficult to fully utilize data from multiple NASA satellites due to the large data volume, the complexity of accessing NASA s data in near-real-time (NRT), as well as the lack of software tools to interact with multi-sensor information. The JPL GRIP Portal is a Web portal that serves a comprehensive set of NRT observation data sets from NASA and NOAA satellites describing the atmospheric and oceanic environments related to the genesis and intensification of the tropical storms in the North Atlantic Ocean. Together with the model forecast data from four major global atmospheric models, this portal provides a useful tool for the scientists and forecasters in planning and monitoring the NASA GRIP field campaign during the 2010 Atlantic Ocean hurricane season. This portal uses the Google Earth plug-in to visualize various types of data sets, such as 2D maps, wind vectors, streamlines, 3D data sets presented at series of vertical cross-sections or pointwise vertical profiles, and hurricane best tracks and forecast tracks. Additionally, it allows users to overlap multiple data sets, change the opacity of each image layer, generate animations on the fly with selected data sets, and compare the observation data with the model forecast using two independent calendars. The portal also provides the capability to identify the geographic location of any point of interest. In addition to supporting the airborne mission planning, the NRT data and portal will serve as a very rich source of information during the post-field campaign analysis stage of the airborne experiment. By including a diverse set of satellite observations and model forecasts, it provides a good spatial and temporal context for the

  8. Petrology and geochemistry of alkali gabbronorites from lunar breccia 67975

    NASA Technical Reports Server (NTRS)

    James, Odette B.; Flohr, Marta K.; Lindstrom, Marilyn M.

    1987-01-01

    Detailed results of petrologic and compositional studies of three clasts found in thin sections of the Apollo 16 lunar breccia 67975 and of four clasts extracted from the breccia (for instrumental neutron activation analysis) prior to thin sectioning are reported. The alkali gabbronorites of the breccia form two distinct subgroups, magnesian and ferroan. The magnesian gabbronorites are composed of bytownitic plagioclase, hypersthene, augite, a silica mineral, and trace Ba-rich K-feldspar. The ferroan gabbronorites are composed of ternary plagioclase, pigeonite, augite, Ba-rich K-feldspar, and a silica mineral. Trace minerals in both subgroups are apatite, REE-rich whitlockite, and zircon. The magnesian and ferroan alkali gabbronorites appear to have formed by progressive differentiation of the same, or closely related, parent REE-rich magmas.

  9. Petrological Explanations for the Magnetic Anomalies Detected on Mars

    NASA Technical Reports Server (NTRS)

    Weitz, C. M.; Rutherford, M. J.

    1999-01-01

    The discovery of crustal magnetization in some locations on Mars, particularly the southern highlands, has major implications for the early evolution of Mars. The east-west-trending linear features in the southern highlands with alternating polarity may be the result of an early seafloor spreading process similar to that seen on Earth today. The larger magnetization of the martian crust compared to the Earth can be attributed to its higher Fe content and the proposed minerals associated with this magnetization are multidomain hematite and pyrrhotite. In this study, we discuss the petrological evolution of basalts on Earth and Mars and suggest processes that may enhance crystallization of magnetic minerals in the martian rocks, thereby accounting for their intense magnetic properties.

  10. Lunar basalt meteorite EET 87521: Petrology of the clast population

    NASA Technical Reports Server (NTRS)

    Semenova, A. S.; Nazarov, M. A.; Kononkova, N. N.

    1993-01-01

    The Elephant Moraine meteorite EET 87521 was classified as a lunar mare basalt breccia which is composed mainly of VLT basalt clasts. Here we report on our petrological study of lithic clasts and monomineralic fragments in the thin sections EET 87521,54 and EET 87521,47,1, which were prepared from the meteorite. The results of the study show that EET 87521 consists mainly of Al-rich ferrobasalt clasts and olivine pyroxenite clasts. The bulk composition of the meteorite can be well modelled by the mixing of these lithic components which appear to be differentiates of the Luna 25 basalt melt. KREEP and Mg-rich gabbro components are minor constituents of EET 87521.

  11. APPLICATIONS OF CATHODOLUMINESCENCE OF QUARTZ AND FELDSPAR TO SEDIMENTARY PETROLOGY.

    USGS Publications Warehouse

    Ruppert, Leslie F.

    1987-01-01

    Cathodoluminescence (CL), the emission of visible light during electron bombardment, was first used in sandstone petrology in the mid-1960's. CL techniques are especially useful for determining the origin and source of quartz and feldspar, two of the most common constituents in clastic rocks. CL properties of both minerals are dependent on their temperature of crystallization, duration of cooling, and/or history of deformation. Detrital quartz and feldspar are typically derived from igneous and metamorphic sources and luminesce in the visible range whereas authigenic quartz and feldspar form at low temperatures and do not luminesce. Quantification of luminescent and non-luminescent quartz and feldspar with the scanning electron microscope, electron microprobe, or a commercial CL device can allow for the determination of origin, diagenesis, and source of clastic rocks when used in conjunction with field and other petrographic analyses.

  12. Petrology, chemistry, age and irradiation history of Luna 24 samples

    NASA Technical Reports Server (NTRS)

    Wasserburg, G. J.; Papanastassiou, D. A.; Mcculloch, M. T.; Huneke, J. C.; Dymek, R. F.; Depaolo, D. J.; Chodos, A. A.; Albee, A. L.; Radicati Di Brozolo, F.

    1978-01-01

    The results of petrological, chemical, isotopic age determination and irradiation studies of sample 24170 from the 170 cm depth of the regolith core returned from Mare Crisium by Luna 24 are presented. The sample is found to be comprised of fragments from a single igneous rock, with mineralogical evidence indicating it to be a mare basalt. The crystallization age is determined by Sm-Nd and Ar(40)-Ar(39) ages to be 3.30 AE, establishing the presence of relatively young flows. All soil samples show low trace element compositions with minimum contamination by KREEPUTh-rich materials. Rb-Sr and Sm-Nd relations reflect the absence of significant fractionation at ages younger than 4.5 AE. One soil sample shows extremely large neutron capture effects, imposing a new lower limit to the neutron production rate in the regolith and requiring the addition of irradiated materials from depth.

  13. Apollo 15 yellow impact glasses: Chemistry, petrology, and exotic origin

    SciTech Connect

    Delano, J.W.; Lindsley, D.H.; Ma, M.; Schmitt, R.A.

    1982-11-15

    The Apollo 15 yellow impact glasses are characterized by moderate TiO/sub 2/ (approx.4.8%) and high abundances of the large ion lithophile elements (e.g., K, P, Hf, Th, REE). Since the chemistry of these glasses cannot be duplicated by any combination of local components presently known to occur at the Apollo 15 landing site, these yellow glasses seem to be exotic to that area. Chemical and petrologic constraints suggest that these samples were produced by impact melting of an immature mare regolith developed upon an unusual variety of mare basalt. We speculate that the target basalt were the youngest lava flows known to exist on the moon (i.e., Eratosphenian-age lavas in Oceanus Procellarum and Mare Imbrium). Specific tests are proposed for evaluating this provocative hypothesis.

  14. Lunar ferroan anorthosite 60025 - Petrology and chemistry of mafic lithologies

    NASA Technical Reports Server (NTRS)

    James, O. B.; Mcgee, J. J.; Lindstrom, M. M.

    1991-01-01

    Eleven splits from the mafic-mineral-rich part of anorthosite 60025 were studied in order to establish the exact nature and causes of compositional variations in the minerals of lunar ferroan anorthosites. All splits were analyzed by INAA, and five were studied intensively by petrologic techniques. All splits were found to have similar cataclastic textures and show textural evidence of at least two episodes of deformation. The whole-rock split contains mafic minerals having a wide range of compositions and is probably polymict. It is suggested that the rare-earth patterns for all splits can be duplicated safactorily, assuming that the equilibrium liquids had flat, or nearly flat, chondrite-normalized rare-earth patterns. The plagioclases in all splits were found to be identical. Data obtained indicate that in ferroan anorthosites An content in plagioclase and mg' of associated mafic minerals are not strongly correlated.

  15. Petrology of crystalline matrix breccias from Apollo 17 rake samples

    NASA Technical Reports Server (NTRS)

    Warner, R. D.; Taylor, G. J.; Keil, K.

    1977-01-01

    The petrology, mineralogy, and composition of 13 crystalline matrix breccias from the Apollo 17 rake samples are described. The breccias have matrices of uniform modal mineralogy (plagioclase, 50-54%; olivine and pyroxene, 41-46%) but diverse textures. Clast characteristics, including the proportion of plagioclase, the composition in comparison with matrix, and the textures of different clast types, are reported. The majority of bulk matrix compositions plot on or very near the plagioclase-olivine cotectic in the system olivine-anorthite-silica. If the matrix compositions represent impact total melts, the inferred cotectic control requires that the source material was itself an igneous differentiate with compositions along the plagioclase-olivine cotectic. Alternatively, the proximity of the matrix compositions to the plagioclase-olivine cotectic could be accounted for if the breccia matrices represent a suite of impact-generated partial melts.

  16. Linking petrology and seismology at an active volcano.

    PubMed

    Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

    2012-05-25

    Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology. PMID:22628652

  17. Morphotectonic and petrological variations along the southern Central Indian Ridge

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Ranadhir; Iyer, Sridhar D.; Ray, Dwijesh; Karisiddaiah, S. M.; Drolia, Rajendra K.

    2016-04-01

    In order to ascertain the effect of geomorphic and tectonic domains on the formation, enrichment, and ascension of the ridge axis melt, structural and petrological data from a nearly 300-km-long axial stretch along the slow-to-intermediate-spreading (40-60 mm/year) southern Central Indian Ridge (SCIR) were studied. The stretch, approximately between 20°30'S and 23°07'S, was disturbed by two major tectonic features—Egeria transform fault in the north and the Gemino Fracture Zone in the south—besides eight other discontinuities of variable dimensions. This stretch was chosen to test the petrological variations and mechanisms of magma supply in four distinct geomorphic and tectonic regimes: a Ridge-Crest-Flank-Valley (RCFV), a Neo-Volcanic Zone (NVZ), a large transform discontinuity (LTD), and an overlapping spreading centre (OSC). The major and trace element geochemistry of 44 glass and 47 whole rocks, extent and depth of melting (Na8 and Fe8, respectively), and melt pristinity (Mg#) of the magma indicate that rocks along this stretch were probably sourced from a reasonably primitive melt generated at a relatively greater depth and later got accumulated in pockets at a shallower level before eruption. Petrochemical analysis, and isotopic composition and ratios suggest that in contrast to largely N-MORB type of rocks at RCFV and OSC areas, the rocks from LTD and NVZ locations show signatures of enrichment to transitional (T) and enriched (E) basalts. A model explaining possible processes of enrichment and ascending framework of the melt at different tectonic regimes along SCIR are discussed.

  18. The petrology and petrogenesis of the Swaldale region, Motzfeldt Center, South Greenland

    NASA Astrophysics Data System (ADS)

    Reekie, Callum; Finch, Adrian

    2016-04-01

    Motzfeldt is one of several high-level alkaline plutonic centers that collectively define the mid-Proterozoic Gardar Province of South Greenland. Despite pyrochlore-hosted Ta-enrichment (± Nb-Zr-REE), the petrology, geochemistry and petrogenesis across the center remain to be fully constrained. We present petrological and geochemical data for the Swaldale region, an arcuate band of nepheline syenite and associated intrusives on Motzfeldt's NW margin. Work for this present study was undertaken in collaboration with the license holder, Regency Mines plc. Swaldale comprises two geochemically distinct magmatic members. The largest, the Motzfeldt Sø Formation (MSF; EuN/Eu*N = 0.35), is a suite of diverse syenite variants that show significant petrological and geochemical heterogeneity. These rocks have a relatively restricted SiO2 range (57.4-62.9 wt.%) with concurrent variation in (Na+K)/Al (0.75-0.95), Mg/(Mg+Fe) (2.18-19.82) and ΣREE (595.0-3095.9 ppm), emphasizing their evolved but not peralkaline nature. Fractionation is mirrored by pyroxene geochemistry with evolution from aegirine-augite, aegirine-hedenbergite, to aegirine. Accessory pyrochlore, titanite, and zircon are rare; however, anomalous facies of zircon-rich (~2 wt.%) syenite are observed. Intercumulus fluorite is a common accessory within MSF rocks. Hydrothermal alteration, marked by hematized alkali-feldspar, is pervasive and ubiquitous. Further peraluminous syenite of the Geologfjeld Formation ((Na+K)/Al = 0.74; EuN/Eu*N = 1.60) marks the truncated remnant of an early syenite stock to the north of the MSF. These rocks contain salite, which, in addition to a lower ΣREE and higher Mg/(Mg+Fe) (18.01), demonstrates the less-fractionated nature of this stock in comparison with the MSF. Sheeted intrusions of peralkaline syenite ((Na+K)/Al = 1.1; Ta = 32.4 ppm) truncate the MSF across central Swaldale. On a mineralogical basis, it is hypothesized that such intrusions reflect outward sheeting of the

  19. Genesis of Carlin-type gold deposits

    SciTech Connect

    Burton, J.C.; Lawler, J.P.; Ayres, D.E.

    1985-01-01

    Carlin-type deposits are large, disseminated, sediment-hosted gold ore bodies. They are of major economic interest to mining companies because they represent low-cost, bulk-mineable targets. To develop a genetic model for the Carlin-type deposits, the authors have employed a multidisciplinary research program on ten Carlin-type deposits in Nevada and Utah. Studies included rock geochemistry, alteration mineralogy, fluid inclusions, oxygen isotopes, incremental Ar/sup 40/-Ar/sup 38/ age dating, hydrothermal experiments on temperature-stability relationships of gold complexes, and physical properties of host rocks. Their studies demonstrate that Carlin-type deposits are formed at initial temperatures of approximately 250/sup 0/C by acidic, reducing, low salinity, Tertiary, meteoric fluids. Gold is transported as a chloride complex and deposition occurs in response to destabilization of this complex with decreasing temperature. Temperature is the major parameter controlling ore deposition. The physical properties of the host environment place major constraints on ore formation in addition to temperature. In the Carlin systems studied, high porosity host rocks are capped by structural or stratigraphic closures which trap the ore fluid. The deposits do not necessarily form near the surface, and models based solely on analogies to hot springs systems may be misleading.

  20. Petrologic constraints on the pressure, temperature, time and composition of the Martian interior

    NASA Technical Reports Server (NTRS)

    Holloway, John R.

    1988-01-01

    Petrologic analysis of surface samples has been used to deduce pressure and temperature conditions existing in the crust and upper mantle at specific times in the Earth's history, as well as to estimate the chemical and mineralogical composition of the crust and upper mantle. The same techniques can be applied to samples of the Martian surface to provide P, T, time and composition constraints of the Martian interior. Estimates of P and T conditions existing at a given time would, in turn, provide strong constraints on the thermal evolution of Mars. Knowledge of the chemical and mineralogical composition of the Martian interior is of fundamental importance in assessing the early history of the solar system. A general petrological approach is outlined, describing the kinds of sample required, summarizing current understanding of the Martian interior based on experimental petrology, and outlining some of the important experiments needed to allow a full petrologic interpretation of Martian samples.

  1. Learning Activities for an Undergraduate Mineralogy/Petrology Course-"I Am/We Are."

    ERIC Educational Resources Information Center

    Goodell, Philip C.

    2001-01-01

    Introduces an entry level mineralogy/igneous petrology course designed for undergraduate students and presents a series of learning activities based on individual and cooperative learning. Includes 18 references. (Author/YDS)

  2. Analysis of Molecular Contamination on Genesis Collectors Through Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, Eileen K.

    2005-01-01

    Before the spacecraft returned to Earth in September, the Genesis mission had a preliminary assessment plan in place for the purpose of providing information on the condition and availability of collector materials to the science community as a basis for allocation requests. One important component of that plan was the evaluation of collector surfaces for molecular contamination. Sources of molecular contamination might be the on-orbit outgassing of spacecraft and science canister components, the condensation of thruster by-products during spacecraft maneuvers, or the condensation of volatile species associated with reentry. Although the non-nominal return of the Genesis spacecraft introduced particulate contamination to the collectors, such as dust and heatshield carbon-carbon, it is unlikely to have caused any molecular deposition. The contingency team's quick action in returning the damaged payload the UTTR cleanroom by 6 PM the evening of recovery help to ensure that exposure to weather conditions and the environment were kept to a minimum.

  3. EV13 Genesis Reentry Observations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.

    2006-01-01

    The Genesis spacecraft reentry represented a unique opportunity to observe a "calibrated meteor" from northern Nevada. Knowing its speed, mass, composition, and precise trajectory made it a good subject to test some of the algorithms used to determine meteoroid mass from observed brightness. It was also a good test of an inexpensive set of cameras which could be deployed to observe future shuttle reentries. The utility of consumer grade video cameras was evident during the STS-107 accident investigation and the Genesis reentry gave us the opportunity to specify and test commercially available cameras which could be used during future reentries. This report describes the video observations and their analysis, compares the results with a simple photometric model, describes the forward scatter radar experiment, and lists lessons learned from the expedition and implications for the Stardust reentry in January 2006 as well as future shuttle reentries.

  4. Nuts and Bolts - Techniques for Genesis Sample Curation

    NASA Technical Reports Server (NTRS)

    Burkett, Patti J.; Rodriquez, M. C.; Allton, J. H.

    2011-01-01

    The Genesis curation staff at NASA Johnson Space Center provides samples and data for analysis to the scientific community, following allocation approval by the Genesis Oversight Committee, a sub-committee of CAPTEM (Curation Analysis Planning Team for Extraterrestrial Materials). We are often asked by investigators within the scientific community how we choose samples to best fit the requirements of the request. Here we will demonstrate our techniques for characterizing samples and satisfying allocation requests. Even with a systematic approach, every allocation is unique. We are also providing updated status of the cataloging and characterization of solar wind collectors as of January 2011. The collection consists of 3721 inventoried samples consisting of a single fragment, or multiple fragments containerized or pressed between post-it notes, jars or vials of various sizes.

  5. [Genesis study of omphacite at high pressure and high temperature].

    PubMed

    Xiao, Ben-Fu; Yi, Li; Wang, Duo-Jun; Xie, Chao; Tang, Xue-Wu; Liu, Lei; Cui, Yue-Ju

    2013-11-01

    The melting and recrystallizing experiments of alkali basalt powder and mixture of pure oxides mixed as stoichiometry were performed at 3 GPa and 1 200 degrees C. Electronic microprobe analysis and Raman spectra showed that the recrystallized products were omphacites, the FWHM (full width at half maximum) of the Raman peak was narrow and its shape was sharp, which is attributed to the stable Si-O tetrahedral structure and the high degree of order in omphacite. Based on the results of previous studies, the influencing factors of omphacite genesis and its primary magma were discussed. The results showed that the formation of omphacite could be affected by many factors, such as the composition of parent rocks, the concentration of fluid in the system and the conditions of pressure and temperature. This result could support some experimental evidences on the genesis studies of omphacite and eclogite. PMID:24555367

  6. Entry Dispersion Analysis for the Genesis Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Desai, Prasun N.; Cheatwood, F. McNeil

    2005-01-01

    Genesis will be the first mission to return samples from beyond the Earth-Moon system. The spacecraft will be inserted into a halo orbit about the L1 (Sun-Earth) libration point where it will remain for two years collecting solar wind particles. Upon Earth return, the sample return capsule, which is passively controlled, will descend under parachute to Utah. The present study describes the analysis of the entry, descent, and landing scenario of the returning sample capsule. The robustness of the entry sequence is assessed through a Monte Carlo dispersion analysis where the impact of off-nominal conditions is ascertained. The dispersion results indicate that the capsule attitude excursions near peak heating and drogue chute deployment are within Genesis mission limits. Additionally, the size of the resulting 3-sigma landing ellipse is 47.8 km in downrange by 15.2 km in crossrange, which is within the Utah Test and Training Range boundaries.

  7. Size Distribution of Genesis Solar Wind Array Collector Fragments Recovered

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Stansbery, E. K.; McNamara, K. M.

    2005-01-01

    Genesis launched in 2001 with 271 whole and 30 half hexagonally-shaped collectors mounted on 5 arrays, comprised of 9 materials described in [1]. The array collectors were damaged during re-entry impact in Utah in 2004 [2], breaking into many smaller pieces and dust. A compilation of the number and approximate size of the fragments recovered was compiled from notes made during the field packaging performed in the Class 10,000 cleanroom at Utah Test and Training Range [3].

  8. Genesis of Typhoon Nari (2001) from a mesoscale convective system

    NASA Astrophysics Data System (ADS)

    Zhang, Da-Lin; Tian, Liqing; Yang, Ming-Jen

    2011-12-01

    In this study, the origin and genesis of Typhoon Nari (2001) as well as its erratic looping track, are examined using large-scale analysis, satellite observations, and a 4 day nested, cloud-resolving simulation with the finest grid size of 1.33 km. Observational analysis reveals that Nari could be traced 5 days back to a diurnally varying mesoscale convective system with growing cyclonic vorticity and relative humidity in the lower troposphere and that it evolved from a mesoscale convective vortex (MCV) as moving over a warm ocean under the influence of a subtropical high, a weak westerly baroclinic disturbance, an approaching-and-departing Typhoon Danas to the east, and the Kuroshio Current. Results show that the model reproduces the genesis, final intensity, looping track, and the general convective activity of Nari during the 4 day period. It also captures two deep subvortices at the eye-eyewall interface that are similar to those previously observed, a few spiral rainbands, and a midget storm size associated with Nari's relatively dry and stable environment. We find that (1) continuous convective overturning within the MCV stretches the low-level vorticity and moistens a deep mesoscale column that are both favorable for genesis; (2) Nari's genesis does not occur until after the passage of the baroclinic disturbance; (3) convective asymmetry induces a smaller-sized vortex circulation from the preexisting MCV; (4) the vortex-vortex interaction with Danas leads to Nari's looping track and temporal weakening; and (5) midlevel convergence associated with the subtropical high and Danas accounts for the generation of a nearly upright eyewall.

  9. Initial Subdivision of Genesis Early Science Polished Aluminum Collector

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Stansbery, E. K.; McNamara, K. M.; Meshik, A.; See, T. H.; Bastien, R.

    2005-01-01

    A large surface, about 245 square centimeters, of highly polished aluminum 6061 T6 alloy was attached to the science canister thermal panel for the purpose of collecting solar wind noble gases. The analysis of this collector will be part of the Genesis Early Science results. The pre-launch configuration of the collector is shown. The collector sustained some damage during the recovery impact in Utah, September 8, 2004.

  10. Genesis Silicon Carbide Concentrator Target 60003 Preliminary Ellipsometry Mapping Results

    NASA Technical Reports Server (NTRS)

    Calaway, M. J.; Rodriquez, M. C.; Stansbery, E. K.

    2007-01-01

    The Genesis concentrator was custom designed to focus solar wind ions primarily for terrestrial isotopic analysis of O-17/O-16 and O-18/O-16 to +/-1%, N-15/N-14 to +/-1%, and secondarily to conduct elemental and isotopic analysis of Li, Be, and B. The circular 6.2 cm diameter concentrator target holder was comprised of four quadrants of highly pure semiconductor materials that included one amorphous diamond-like carbon, one C-13 diamond, and two silicon carbide (SiC). The amorphous diamond-like carbon quadrant was fractured upon impact at Utah Test and Training Range (UTTR), but the remaining three quadrants survived fully intact and all four quadrants hold an important collection of solar wind. The quadrants were removed from the target holder at NASA Johnso n Space Center Genesis Curation Laboratory in April 2005, and have been housed in stainless steel containers under continual nitrogen purge since time of disintegration. In preparation for allocation of a silicon carbide target for oxygen isotope analyses at UCLA, the two SiC targets were photographed for preliminary inspection of macro particle contamination from the hard non-nominal landing as well as characterized by spectroscopic ellipsometry to evaluate thin film contamination. This report is focused on Genesis SiC target sample number 60003.

  11. Genesis Solar-Wind Sample Return Mission: The Materials

    NASA Technical Reports Server (NTRS)

    Jurewicz, A. J. G.; Burnett, D. S.; Wiens, R. C.; Woolum, D.

    2003-01-01

    The Genesis spacecraft has two primary instruments which passively collect solar wind. The first is the collector arrays , a set of panels, each of which can deploy separately to sample the different kinds of solar wind (regimes). The second is the concentrator, an electrostatic mirror which will concentrate ions of mass 4 through mass 25 by about a factor of 20 by focusing them onto a 6 cm diameter target. When not deployed, these instruments fit into a compact canister. After a two year exposure time, the deployed instruments can be folded up, sealed into the canister, and returned to earth for laboratory analysis. Both the collector arrays and the concentrator will contain suites of ultra-high purity target materials, each of which is tailored to enable the analysis of a different family of elements. This abstract is meant to give a brief overview of the Genesis mission, insight into what materials were chosen for flight and why, as well as head s up information as to what will be available to planetary scientist for analysis when the solar-wind samples return to Earth in 2003. Earth. The elemental and isotopic abundances of the solar wind will be analyzed in state-of-the-art laboratories, and a portion of the sample will be archived for the use of future generations of planetary scientists. Technical information about the mission can be found at www.gps.caltech.edu/genesis.

  12. A model for genesis of transcription systems.

    PubMed

    Burton, Zachary F; Opron, Kristopher; Wei, Guowei; Geiger, James H

    2016-01-01

    Repeating sequences generated from RNA gene fusions/ligations dominate ancient life, indicating central importance of building structural complexity in evolving biological systems. A simple and coherent story of life on earth is told from tracking repeating motifs that generate α/β proteins, 2-double-Ψ-β-barrel (DPBB) type RNA polymerases (RNAPs), general transcription factors (GTFs), and promoters. A general rule that emerges is that biological complexity that arises through generation of repeats is often bounded by solubility and closure (i.e., to form a pseudo-dimer or a barrel). Because the first DNA genomes were replicated by DNA template-dependent RNA synthesis followed by RNA template-dependent DNA synthesis via reverse transcriptase, the first DNA replication origins were initially 2-DPBB type RNAP promoters. A simplifying model for evolution of promoters/replication origins via repetition of core promoter elements is proposed. The model can explain why Pribnow boxes in bacterial transcription (i.e., (-12)TATAATG(-6)) so closely resemble TATA boxes (i.e., (-31)TATAAAAG(-24)) in archaeal/eukaryotic transcription. The evolution of anchor DNA sequences in bacterial (i.e., (-35)TTGACA(-30)) and archaeal (BRE(up); BRE for TFB recognition element) promoters is potentially explained. The evolution of BRE(down) elements of archaeal promoters is potentially explained. PMID:26735411

  13. A model for genesis of transcription systems

    PubMed Central

    Burton, Zachary F.; Opron, Kristopher; Wei, Guowei; Geiger, James H.

    2016-01-01

    ABSTRACT Repeating sequences generated from RNA gene fusions/ligations dominate ancient life, indicating central importance of building structural complexity in evolving biological systems. A simple and coherent story of life on earth is told from tracking repeating motifs that generate α/β proteins, 2-double-Ψ−β-barrel (DPBB) type RNA polymerases (RNAPs), general transcription factors (GTFs), and promoters. A general rule that emerges is that biological complexity that arises through generation of repeats is often bounded by solubility and closure (i.e., to form a pseudo-dimer or a barrel). Because the first DNA genomes were replicated by DNA template-dependent RNA synthesis followed by RNA template-dependent DNA synthesis via reverse transcriptase, the first DNA replication origins were initially 2-DPBB type RNAP promoters. A simplifying model for evolution of promoters/replication origins via repetition of core promoter elements is proposed. The model can explain why Pribnow boxes in bacterial transcription (i.e., −12TATAATG−6) so closely resemble TATA boxes (i.e., −31TATAAAAG−24) in archaeal/eukaryotic transcription. The evolution of anchor DNA sequences in bacterial (i.e., −35TTGACA−30) and archaeal (BREup; BRE for TFB recognition element) promoters is potentially explained. The evolution of BREdown elements of archaeal promoters is potentially explained. PMID:26735411

  14. Teaching Petrology in the 21st Century: A Workshop Report and Call to Action

    NASA Astrophysics Data System (ADS)

    Mogk, D.; Davidson, C.; Manduca, C.; Braday, J.

    2003-12-01

    Petrology plays an important role in the upper division geology curriculum, introducing students to the skills needed to investigate and interpret igneous and metamorphic rocks that form the bulk of the earth's interior. Central concepts in petrology courses typically include chemical differentiation of Earth, the role of igneous and metamorphic processes in the Earth system, and the occurrences and distribution of rocks and in a variety of tectonic settings. Seventy-nine geoscientists who teach (or plan to teach) petrology in the undergraduate curriculum gathered for a week at Montana State University this past summer to discuss best practices and how petrology should be integrated into the geology curriculum of the 21st century. The first three days of the workshop were devoted to visiting some of the classic geological field locations in Montana and Wyoming to discuss the role of fieldwork in teaching petrologic concepts. The following four days were spent on the MSU campus in a mixture of large group discussions, smaller topical working group meetings, and demonstration sessions where faculty presented exercises, laboratory activities, or moderated small group discussions on pedagogy and assessment. One of the main outcomes of the workshop was the development of a web site for sharing teaching materials (http://serc.carleton.edu/NAGTWorkshops/petrology03). This site contains a complete record of workshop activities. A collection of over 200 digital resources that support teaching petrology is now available, including over 30 new instructional activities contributed by workshop participants. Each activity contains 1) a brief introduction to the activity; 2) the activity itself along with supporting documents such as teaching notes and an answer key; and 3) a place for comments by users to give feedback to the author and to those who might be interested in using the activity. A formal review process of these resources will be initiated in the coming year. Another

  15. Raman microspectroscopy: a powerful analytic and imaging tool in petrology and geochemistry

    NASA Astrophysics Data System (ADS)

    Beyssac, O.

    2013-12-01

    Raman microspectroscopy is a vibrational spectroscopy based on the inelastic scattering of light interacting with molecules. This technique has benefited from recent developments in spectral and spatial resolution as well as sensitivity which make it widely used in Geosciences. A very attractive aspect of Raman spectroscopy is that it does not require any complex sample preparation. In addition, Raman imaging is now a routine and reliable technique which makes it competitive with SEM-EDS mapping for mineral mapping for instance. Raman microspectroscopy is a complementary technique to SEM, EMP, SIMS... as it can provide not only information on mineral chemistry, but overall on mineral structure. Raman Microspectroscopy is for instance the best in situ technique to distinguish mineral polymorphs. In addition the sensitivity of RM to mineral structure is extremely useful to study accessory minerals like oxides or sulphides as well as graphitic carbons. A brief presentation of the analytical capabilities of modern Raman spectroscopy will be presented. Then recent applications of RM in petrological and geochemical problems will be reviewed, including Raman imaging. The advantages and disadvantages of this technique compared to other micro-analytic tools will be discussed.

  16. Cracking the code: the genesis, use and future of the Code of Conduct.

    PubMed

    Walker, Peter

    2005-12-01

    This paper reflects on the genesis of the Code of Conduct for the International Red Cross and Red Crescent Movement and Non-Governmental Organizations (NGOs) in Disaster Relief, on the tenth anniversary of its adoption. The origins, usage and future of the code are examined with respect to three debates, current at the time of its inception, namely: the debate about the core content of humanitarianism; the debate about coherence and the consensual nature of the humanitarian community; and the debate about the need for, and the ability to demonstrate, accountability. The paper concludes that although the Code of Conduct was very much a product of its time, its content remains relevant today. However, its future application hinges on the capacity of those who purport to follow it to realise true accountability, and on proving that the code, written essentially for natural disasters, is relevant to contemporary complex emergencies. PMID:16277643

  17. Study on the genesis of Yishui banded iron formation (BIF) in the North China Craton: geochemical characteristics and tectonic environment

    NASA Astrophysics Data System (ADS)

    Moon, I.; Lee, I.; Yang, X.

    2015-12-01

    The Yishui BIFs are located in the Taishan Group, Shandong province of Eastern Block of North China Craton. The iron ore samples were collected from the mine pits. Major elements were analyzed by X-ray Fluoresence Spectromemter (XRF). Trace elements and REY (REE + Y) were analyzed by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Petrological, mineralogical and geochemical analyses of iron ores and their wall rock (amphibolite) were conducted to trace the genesis of Yishui BIF. Iron ores of Yishui BIF are mainly composed of SiO2 and Fe2O3T (SiO2+ Fe2O3T= 85.8 to 98.8 wt%) and consistent with major mineral components which are quartz and iron oxide such as magnetite and hematite. Low contents of TiO2 (0.01 to 0.09 wt%) , Al2O3 (0.42 to 1.18 wt%) and HFSE indicate no or little effect of detrital contamination. Iron ores have positive La, Eu, Gd, Er and Y anomalies with enriched HREE in PAAS normalized REY graph. The REY patterns of iron ores were used as a fingerprint to trace the source of iron and silica. Distinctive positive Eu anomalies (Eu/Eu*= 2.44-4.19), Y anomalies (Y/Y*=0.97 - 4.19), slightly negative Ce anomalies (Ce/Ce*= 0.87-0.97) and enriched HREE ((La/Yb)SN= 0.17-0.32) indicate that mixture of seawater and high-temperature hydrothermal fluid (>250 ◦C). Depositional environment in North China Craton implies that Yishui BIFs were formed at Neoarchean and associated arc-related tectonic setting. All these data suggest that Yishui BIFs belong to typical Algoma-type BIF.

  18. Rethinking how Undergraduate ``Hard Rock'' Petrology is Taught

    NASA Astrophysics Data System (ADS)

    Reid, M. R.

    2010-12-01

    A course in "hard rock" petrology forms a core component of undergraduate training in the geosciences. In most cases, the subjects of igneous and metamorphic petrology are combined in a single course and the course is traditionally structured so that the two subjects are covered in series. This approach enables students to focus on each subject separately, with knowledge of igneous rocks helping students to understand metamorphic rock protoliths. Student assessment shows, however, that this approach tends to compartmentalize learning and the two main subjects might just as well be taught in separate courses. In practical applications such as fieldwork, students must be able to access their understanding of igneous and metamorphic rocks virtually simultaneously. To better integrate student learning, I developed a spiral learning approach to teaching petrology (e.g., Bruner, 1990; Dyar et al., 2004) so that commonalities could be revisited several times over the course of a semester and, in so doing, students' grasp of the fundamental insights provided by igneous and metamorphic rocks could be scaffolded into greater understanding. The course initially focuses on the dynamics of the environments in which igneous and metamorphic rocks form: heat flow, fluid flow, and plate tectonics. Several subsequent weeks explore topics relevant to identifying and understanding igneous and metamorphic rocks in the field: crystal nucleation and growth, the roles of pressure and heat, and field classification. Laboratory exercises parallel this structure, also emphasizing observations that are valuable in the field: the relationship between minerals and rocks, textural observations, and general rock classification. The final portion of the course explores “hard rocks” in more detail with a greater emphasis on the interplay between chemistry and mineralogy. A variety of learner-centered activities in the course help students bridge the gap between novice and expert and include

  19. Petrology of the anorogenic, oxidised Jamon and Musa granites, Amazonian Craton: implications for the genesis of Proterozoic A-type granites

    NASA Astrophysics Data System (ADS)

    Dall'Agnol, Roberto; Rämö, O. Tapani; de Magalhães, Marilia Sacramento; Macambira, Moacir José Buenano

    1999-03-01

    The 1.88 Ga Jamon and Musa granites are magnetite-bearing anorogenic, A-type granites of Paleoproterozoic age. They intrude the Archaean rocks of the Rio Maria Granite-Greenstone Terrain in the eastern part of the Amazonian Craton in northern Brazil. A suite of biotite±amphibole monzogranite to syenogranite, with associated dacite porphyry (DP) and granite porphyry (GP) dykes, dominates in these subalkaline granites that vary from metaluminous to peraluminous and show high FeO/(FeO+MgO) and K 2O/Na 2O. In spite of their broad geochemical similarities, the Jamon and Musa granites show some significant differences in their REE patterns and in the behaviour of Y. The Jamon granites are related by fractional crystallisation of plagioclase, potassium feldspar, quartz, biotite, magnetite±amphibole±apatite±ilmenite. Geochemical modelling and Nd isotopic data indicate that the Archaean granodiorites, trondhjemites and tonalites of the Rio Maria region are not the source of the Jamon Granite and associated dyke magmas. Archaean quartz diorites, differentiated from the mantle at least 1000 m.y. before the emplacement of the granites, have a composition adequate to generate DP and the hornblende-biotite monzogranite magmas by different degrees of partial melting. A larger extent of amphibole fractionation during the evolution of the Musa pluton can explain some of the observed differences between it and the Jamon pluton. The studied granites crystallised at relatively high fO 2 and are anorogenic magnetite-series granites. In this aspect, as well as concerning geochemical characteristics, they display many affinities with the Proterozoic A-type granites of south-western United States. The Jamon and Musa granites differ from the anorthosite-mangerite-charnockite-rapakivi granite suites of north-eastern Canada and from the reduced rapakivi granites of the Fennoscandian Shield in several aspects, probably because of different magmatic sources.

  20. An Impact Genesis for Loki Patera?

    NASA Technical Reports Server (NTRS)

    Thorsos, I. E.; Davies, A. G.

    2005-01-01

    What happens when a large impact event takes place on a satellite with a thin crust and lithosphere? In the early Solar System impact cratering and volcanism were the dominate processes shaping the surfaces of the terrestrial planets. Impact events may have triggered additional volcanism by uplifting partially molten mantle material to the surface, where it melts due to pressure release. Subsequently, the shattered crust may have provided pathways for magma to reach the surface creating a longer term hot spot. As the crusts of the terrestrial planets thickened, the ability of impacts to trigger volcanism diminished [1]. However, the highly-volcanic jovian satellite Io is located in a "high-impact" area of the Solar System [2], a victim of material attracted by Jupiter s gravitational field. In 1994 huge impacts were observed when fragments of comet Shoemaker- Levy 9 impacted Jupiter. The large icy satellites of Jupiter (Europa, Ganymede and Callisto) are pockmarked with many impact craters. Yet no impact features have been found on Io [3]. This is because of rapid resurfacing of Io due to volcanism, estimated at approx.1 cm/year [4] which over short geological time erases evidence of impacts. Io, however, has a lithosphere over a molten or partially-molten mantle [e.g., 5], and the effects of a sufficiently large impact may extend far beyond the evolution of the impact crater alone. At least one example of impact-triggered volcanism may exist in the Solar System today: the Loki Patera complex on Io.

  1. On the genesis of the Earth's magnetism.

    PubMed

    Roberts, Paul H; King, Eric M

    2013-09-01

    Few areas of geophysics are today progressing as rapidly as basic geomagnetism, which seeks to understand the origin of the Earth's magnetism. Data about the present geomagnetic field pours in from orbiting satellites, and supplements the ever growing body of information about the field in the remote past, derived from the magnetism of rocks. The first of the three parts of this review summarizes the available geomagnetic data and makes significant inferences about the large scale structure of the geomagnetic field at the surface of the Earth's electrically conducting fluid core, within which the field originates. In it, we recognize the first major obstacle to progress: because of the Earth's mantle, only the broad, slowly varying features of the magnetic field within the core can be directly observed. The second (and main) part of the review commences with the geodynamo hypothesis: the geomagnetic field is induced by core flow as a self-excited dynamo. Its electrodynamics define 'kinematic dynamo theory'. Key processes involving the motion of magnetic field lines, their diffusion through the conducting fluid, and their reconnection are described in detail. Four kinematic models are presented that are basic to a later section on successful dynamo experiments. The fluid dynamics of the core is considered next, the fluid being driven into motion by buoyancy created by the cooling of the Earth from its primordial state. The resulting flow is strongly affected by the rotation of the Earth and by the Lorentz force, which alters fluid motion by the interaction of the electric current and magnetic field. A section on 'magnetohydrodynamic (MHD) dynamo theory' is devoted to this rotating magnetoconvection. Theoretical treatment of the MHD responsible for geomagnetism culminates with numerical solutions of its governing equations. These simulations help overcome the first major obstacle to progress, but quickly meet the second: the dynamics of Earth's core are too complex

  2. Petrology of four clasts from consortium breccia 73215

    NASA Technical Reports Server (NTRS)

    James, O. B.; Hammarstrom, J. G.

    1977-01-01

    One felsite ('granite') and three ANT-suite anorthositic gabbro clasts extracted from breccia 73215 are described. The felsite clast has two components - fragments of crystalline felsite and veins and patches of felsic glass. The crystalline felsite, which consists largely of a vermicular intergrowth of quartz and Ba-K-feldspar, crystallized from a highly differentiated melt between 3.90 and 4.05 b.y. The felsic glass component consists of crystallized brown and colorless glasses and uncrystallized colorless glass which are all K and Si rich. The relation of glass features to past heating and the breccia-forming event is considered. In the three anorthositic gabbros, which have similar mineralogies and gradational textures, plagioclase is dominant, and olivine and orthopyroxene are the major mafic minerals. The petrologic data suggest that the gabbros formed as heated, partly melted, and/or recrystallized polymict breccias. It is possible that the approximately 4.25 b.y. age obtained for the three rocks is the date of the melting/recrystallization event.

  3. Mineralogical-petrological characterization of near-earth asteroids

    NASA Astrophysics Data System (ADS)

    McFadden, L. A.; Gaffey, M. J.; McCord, T. B.

    1984-07-01

    The mineralogy and petrology of 17 near-earth asteroids are characterized using reflectance spectroscopy with ground-based telescopes. Assuming the surfaces are composed of cosmically abundant materials, the presence of certain mineralogical species can be determined from diagnostic absorption features and spectral characteristics which have been studied under known laboratory conditions and understood in terms of crystal-field theory. With one possible exception, the surface composition of near-earth asteroids consists of common rock-forming minerals such as olivine, pyroxene, and phyllosilicates. Opaque components are present but cannot be mineralogically identified with existing experimental data. The spectrum of 2201 Oljato cannot be interpreted in terms of common rock-forming minerals and is examined for cometary features because its high orbital eccentricity suggests a possible relation to comets, but no common cometary features are identified. The predominance of mafic silicate absorption features in spectra of near-earth asteroids (compared to the majority of main-belt asteroids) may be a primary compositional feature or may be the signature of relatively fresher asteroid material.

  4. Isotopic, petrologic and biogeochemical investigations of banded iron-formations

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.; Kaufman, A. J.; Klein, C.; Studley, S. A.; Baur, M. E.; Walter, M. R.

    1986-01-01

    It is recognized that the first occurrence of banded iron-formations (BIFs) clearly predates biological oxygenation of the atmosphere-hydrosphere system and that their last occurrences extend beyond plausible dates of pervasive biological oxygenation. For this reason, and because enormous quantities of oxidizing power have been sequestered in them, it is widely thought that these massive, but enigmatic, sediments must encode information about the mechanism and timing of the rise of atmospheric O2. By coupling isotopic analyses of iron-formation carbonates with biogeochemical and petrologic investigations, we are studying (1) the mechanism of initial sedimentation of iron; (2) the role of iron in microbially mediated diagenetic processes in fresh iron-formation sediments; and (3) the logical integration of mechanisms of deposition with observed levels of banding. Thus far, it has been shown that (1) carbonates in BIFs of the Hamersley Group of Western Australia are isotopically inhomogenous; (2) the nature and pattern of isotopic ordering is not consistent with a metamorphic origin for the overall depletion of C-13 observed in the carbonates; (3) if biological, the origin of the C-13 depleted carbonate could be either respiratory or fermentative; (4) iron may have been precipitate d as Fe(3+), then reduced to Fe(2+) within the sediment; and (5) sedimentary biogeochemical systems may have been at least partially closed to mass transport of carbonate species.

  5. Towards the Petrophysics and Petrology of Earth's Deep Mantle and the Core Mantle Boundary

    NASA Astrophysics Data System (ADS)

    Mueller, H. J.

    2010-12-01

    Petrophysics measures the physical properties of rocks. Petrology investigates the physical and chemical conditions of their formation as well as attempts to unscramble the p-T-path of a multi-phase development. Petrology is focussed on investigating the shifting equilibrium conditions between the different minerals constituting the crystalline rocks. Because the knowledge is mostly derived from powder high pressure experiments the perspective is mainly chemical and mineralogical. On the other hand experimental petrophysics only exists because structure and texture of a real rock has a vast influence on the resulting physical properties, i.e. the physical rock properties cannot simply derived from the properties of a mixture of the rock constituting minerals. From seismic tomography we know, subduction can reach the core mantle boundary and results in geochemical piles there. The elastic properties of these areas exactly correspond to them of partial molten mineral assemblages, in other words - partial molten rocks. This is a problem because the estimated in situ conditions - 140 GPa and 2900 degrees centigrade - should suppress melting. But there is also another problem. From high pressure experiments we have some knowledge about mineral phases stable under the conditions of the D''. The elastic properties of these minerals correspond quite good with seismological results - quite good but not sufficient. Looking in detail this is not surprising. Because of the very high pressures the critical experiments were carried out in diamond anvil cells and because of the necessarily small sample size mostly using single crystals, or at least mono-mineral polycrystals. But the whole mantle especially the ultradeep subducted plates consist of complex rocks of course. Above-mentioned we had noticed the elastic properties of fine-grained mineral mixtures do not equal the corresponding textured rock samples. If this is true under crustal conditions there is no doubt it is also

  6. GENESI-DR Portal: a scientific gateway to distributed repositories

    NASA Astrophysics Data System (ADS)

    Goncalves, Pedro; Brito, Fabrice; D'Andria, Fabio; Cossu, Roberto; Fusco, Luigi

    2010-05-01

    GENESI-DR (Ground European Network for Earth Science Interoperations - Digital Repositories) is a European Commission (EC)-funded project, kicked-off early 2008 lead by ESA; partners include Space Agencies (DLR, ASI, CNES), both space and no-space data providers such as ENEA (I), Infoterra (UK), K-SAT (N), NILU (N), JRC (EU) and industry as Elsag Datamat (I), CS (F) and TERRADUE (I). GENESI-DR intends to meet the challenge of facilitating "time to science" from different Earth Science disciplines in discovery, access and use (combining, integrating, processing, …) of historical and recent Earth-related data from space, airborne and in-situ sensors, which are archived in large distributed repositories. "Discovering" which data are available on a "geospatial web" is one of the main challenges ES scientists have to face today. Some well- known data sets are referred to in many places, available from many sources. For core information with a common purpose many copies are distributed, e.g., VMap0, Landsat, and SRTM. Other data sets in low or local demand may only be found in a few places and niche communities. Relevant services, results of analysis, applications and tools are accessible in a very scattered and uncoordinated way, often through individual initiatives from Earth Observation mission operators, scientific institutes dealing with ground measurements, service companies or data catalogues. In the discourse of Spatial Data Infrastructures, there are "catalogue services" - directories containing information on where spatial data and services can be found. For metadata "records" describing spatial data and services, there are "registries". The Geospatial industry coins specifications for search interfaces, where it might do better to reach out to other information retrieval and Internet communities. These considerations are the basis for the GENESI-DR scientific portal, which adopts a simple model allowing the geo-spatial classification and discovery of

  7. Mare basalt genesis - Modeling trace elements and isotopic ratios

    NASA Astrophysics Data System (ADS)

    Binder, A. B.

    1985-11-01

    Various types of mare basalt data have been synthesized, leading to the production of an internally consistent model of the mare basalt source region and mare basalt genesis. The model accounts for the mineralogical, major oxide, compatible siderophile trace element, incompatible trace element, and isotopic characteristics of most of the mare basalt units and of all the pyroclastic glass units for which reliable data are available. Initial tests of the model show that it also reproduces the mineralogy and incompatible trace element characteristics of the complementary highland anorthosite suite of rocks and, in a general way, those of the lunar granite suite of rocks.

  8. Dividing the Concentrator Target From the Genesis Mission

    NASA Technical Reports Server (NTRS)

    Lauer, H. V., Jr.; Burkett, P. J.; Clemett, S. J.; Gonzales, C. P.; Nakamura-Messenger, K.; Rodriquez, M. C.; See, T. H.; Sutter, B.

    2014-01-01

    The Genesis spacecraft, launched in 2001, traveled to a Lagrangian point between the Earth and Sun to collect particles from the solar wind and return them to Earth. However, during the return of the spacecraft in 2004, the parachute failed to open during descent, and the Genesis spacecraft crashed into the Utah desert. Many of the solar wind collectors were broken into smaller pieces, and the field team rapidly collected the capsule and collector pieces for later assessment. On each of the next few days, the team discovered that various collectors had survived intact, including three of four concentrator targets. Within a month, the team had imaged more than 10,000 fragments and packed them for transport to the Astromaterials Acquisition and Curation Office within the ARES Directorate at JSC. Currently, the Genesis samples are curated along with the other extraterrestrial sample collections within ARES. Although they were broken and dirty, the Genesis solar wind collectors still offered the science community the opportunity to better understand our Sun and the solar system as a whole. One of the more highly prized concentrator collectors survived the crash almost completely intact. The Genesis Concentrator was designed to concentrate the solar wind by a factor of at least 20 so that solar oxygen and nitrogen isotopes could be measured. One of these materials was the Diamond-on-Silicon (DoS) concentrator target. Unfortunately, the DoS concentrator broke on impact. Nevertheless, the scientific value of the DoS concentrator target was high. The Genesis Allocation Committee received a request for approximately 1 cm(sup 2) of the DoS specimen taken near the focal point of the concentrator for the analysis of solar wind nitrogen isotopes. The largest fragment, Genesis sample 60000, was designated for this allocation and needed to be precisely cut. The requirement was to subdivide the designated sample in a manner that prevented contamination of the sample and minimized

  9. [Hypotheses for the genesis of cancer: a historical perspective].

    PubMed

    Morange, Michel

    2014-01-01

    The explanation of cancer has always been tightly related to the state of knowledge in biology, and its transformations. The present situation is not different. New techniques, such as deep sequencing, are rapidly moving our vision of cancer in an impredictable way. Systems biology, epigenetics, and the study of stem cells are generating new hypotheses on cancer and its evolution. New roles for aleatory events in the genesis of cancer have been proposed. In the traditional opposition between holism and reductionism, organisms and molecules, an intermediary level, the cancer cell, seems to be the most appropriate to study oncogenesis. PMID:25014461

  10. Fabrication of Genesis Sample Simulants Using Plasma Source Ion Implantation (PSII)

    NASA Technical Reports Server (NTRS)

    Kuhlman, K. R.

    2002-01-01

    Plasma source ion implantation can be used to fabricate simulant samples for the Genesis mission. These simulants will be needed by investigators to validate sample preparation and analysis techniques for the returned Genesis samples. Additional information is contained in the original extended abstract.

  11. Petrological variability in recent magmatism at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Dreyer, B. M.; Clague, D. A.; Gill, J. B.

    2011-12-01

    Axial Seamount is known for its compositional homogeneity. We report on petrological variability in lavas from the summit caldera and rims of Axial Seamount during the last ~1.2ka and its implications for shallow crustal magma dynamics. AUVs have mapped the summit at ~1 m resolution, and ROVs have collected numerous lavas and volcaniclastic cores. Geospatial, superpositional, compositional, and age constraint data were used to outline flow units and construct geologic maps. Nearly 200 glasses from summit lavas were analyzed for major elements. A subset of ~20 samples were analyzed for selected trace elements, Pb-, U-, and Th- isotope ratios, and 226Ra and 210Pb. The results a) confirm a high degree compositional homogeneity, b) demonstrate a more restricted range in Pb-isotope ratios than previous data, c) indicate uniform compositional source component(s) genetically linked to that of the Cobb-Eickelberg seamount chain, and d) expand the dataset of distinctly-low 230Th/232Th lavas and subdivide them into geospatial groups. Hundreds of volcaniclastic grains collected from subsurface depths of up to several tens of cm analyzed for major elements extend the record of summit magmatism beyond what is exposed. Summit lava glasses are compositionally N-MORB. Summit volcaniclastics range to higher MgO (+1%); thus, magmatism likely included more mafic episodes than is recorded in the flows as yet sampled or that volcaniclastics preferentially sample higher temperature lavas. Negative correlation of CaO/Al2O3 with MgO in all glasses suggests fractionation from parental melt(s) of plag ± ol but not cpx. K2O/TiO2 ranges are typical for much of the JdFR. Summit lavas range from aphyric to ~35% plag phyric ± a few % ol. Plag-phyric summit lavas tend to have greater MgO (>7.5%), lower CaO/Al2O3 (<0.80), and lower K2O/TiO2 (<0.10) compared to aphyric lavas. For ~18 caldera flows with absolute or relative age control, plag-phyric lavas are older than aphyric lavas, the oldest of

  12. Petrologic Insights into Magma System Response to Edifice Collapse

    NASA Astrophysics Data System (ADS)

    Shipman, J. S.; Izbekov, P. E.; Gavrilenko, M.

    2011-12-01

    In order to understand eruptive behavior at volcanic centers and to improve models for monitoring and prediction of volcanic eruptions, it is important to constrain magma storage conditions and transport in the system. Here the post-collapse eruptive behavior at Bezymianny and Shiveluch volcanoes, (Kamchatka Peninsula, Russia) are each compared to the well-known sequence at Mount St. Helens, Washington, USA (from 1956, 1964, and 1980, respectively). The magma system responds to rapid unloading of overburden pressure, due to edifice collapse, with a violent large-scale paroxysmal eruption. This reflects the amplitude of the triggering decompression event with later dome-building and explosive activity due to the reduction of vent elevation. The massive unloading events and post-collapse eruptive chronologies, provides a unique opportunity for comparison of the sources driving the catastrophic eruptions and eruptive style transitions. Analytical techniques employed included X-ray fluorescence spectroscopy, electron probe micro-analyses, Fe-Ti oxide and two-pyroxene geothermometry, X-ray elemental mapping, and a novel image processing technique. Presented here are results from petrological investigations into the temporal variations of whole-rock geochemistry, geothermometry, mineral modal abundances and textures. Bezymianny is becoming more mafic over time from 61.0 to 57.3 wt.% SiO2 (1956 and 2010). Pre-eruptive magma temperatures increased from 950oC to 1050oC from 1956 to 2006. Plagioclase and amphibole disequilibrium textures are observed throughout the time series and rare mafic enclaves exist. The whole-rock chemical trend at Shiveluch shows a subtle, yet reversed trend from 60.6 to 64.2 wt.% SiO2 (1964 and 2007). Two-pyroxene geothermometry yields ~950oC+30oC (2001-2007) and is consistent with data from the 2001 -2004 eruption, of 834-978oC+60oC. Mafic enclaves occurred throughout the entire period of eruptive activity at Shiveluch. In contrast to both

  13. Petrology of the Upper Border Series of the Skaergaard Intrusion

    NASA Astrophysics Data System (ADS)

    Salmonsen, L.; Tegner, C.; Jakobsen, J. K.

    2009-12-01

    Layered Series are similar in the early stages of differentiation until after FeTi-oxides appear as primocrysts. In the more evolved rocks the Upper Border Series is gradually enriched in SiO2, K2O and incompatible trace elements relative to the Layered Series as shown by Naslund (1984). This is expressed by abundant interstitial granophyre pockets between the cumulus crystals in the Upper Border Series. However, we find that it is possible to explain the Upper Border Series as a mixture of cumulus minerals and reasonable liquid estimates. Thus the Upper Border Series appears to trap a higher fraction of residual liquid than is the case in the Layered Series. We conclude that the Upper Border Series crystallized from the same liquid as the Layered Series and mainly differs in a high amount of trapped liquid. This implies that the Skaergaard chamber had only one convecting magma body. References: Naslund, H.R.; Petrology of the Upper Border Series of the Skaergaard Intrusion, Journal of Petrology, Vol. 25, Part 1, pp 185-212, 1984

  14. Cryosols of the Northeast Siberian Lena River Delta and its hinterland - genesis and diversity

    NASA Astrophysics Data System (ADS)

    Zubrzycki, Sebastian; Kutzbach, Lars; Pfeiffer, Eva-Maria

    2016-04-01

    The North-Siberian Lena River Delta (LRD) is the largest Arctic delta and an important interface between the Arctic Ocean in the North and the large Siberian land masses in the South. LRD consists not only of Holocene deltaic sediment deposits as a river terrace and the modern active floodplains but also of remnants of the former Pleistocene mainland including large islands of ice-complex sediments and the Arga-Muora-Sise Island, which is composed of pure sand sediments of still debated origin. The highly diverse landscape structure of LRD is reflected by a great variety of permafrost-affected soils (cryosols). This study aims at describing this great cryosol diversity and at analysing the dominant soil-forming processes in this comparatively scarcely studied soil region. The soil development in the investigated continuous permafrost region is limited by the short thawing period of around three months (June to September) and takes place in the shallow (below 1 m) seasonally thawed active layer. The geological parent material plays an important role for the development of soils in the LRD region. The distribution of the various soil types closely follows the pattern of the geomorphic units characterised by differing sedimentation conditions. The properties and genesis of the soils on the Holocene river terrace and the modern floodplains are strongly affected by the enormous amounts of fluvial sediments (about 12 x 106 tons per year) brought by the Lena River into its delta. The fluvial sedimentation together with the also pronounced aeolian sedimentation results in a fast vertical growth of soils. The upward rise of the soil surface leads to an upward movement of the permafrost table resulting in fast incorporation of soil material formed in the supra-permafrost zone into the permafrost. Due to the morphodynamics of ice-wedge polygons and resulting formation of patterned ground with elevated rims and depressed and water-saturated centres, the Holocene river terrace

  15. Petrologic evidence for collisional heating of chondritic asteroids

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.

    1995-01-01

    The identification of the mechanism(s) responsible for heating asteroids is among the major problems in planetary science. Because of difficulties with models of electromagnetic induction and the decay of short-lived radionuclides, it is worthwhile to evaluate the evidence for collisional heating. New evidence for localized impact heating comes from the high proportion of relict type-6 material among impact-melt-bearing ordinary chondrites (OC). This relict material was probably metamorphosed by residual heat within large craters. Olivine aggregates composed of faceted crystals with 120 deg triple junctions occur within the melted regions of the Chico and Rose City OC melt rocks; the olivine aggregates formed from shocked, mosaicized olivine grains that underwent contact metamorphism. Large-scale collisional heating is supoorted by the correlation in OC between petrologic type and shock stage; no other heating mechanism can readily account for this correlation. The occurrence of impact-melt-rock clasts in OC that have been metamorphosed along with their whole rocks indicates that some impact events preceded or accompanied thermal metamorphism. Such impacts events, occurring during or shortly after accretion, are probably responsible for substantially melting approximately 0.5% of OC. These events must have heated a larger percentage of OC to subsolidus temperatures sufficient to have caused significant metamorphism. If collisional heating is viable, then OC parent asteroids must have been large; large OC asteroids in the main belt may include those of the S(IV) spectral subtype. Collisional heating is inconsistent with layered ('onion-shell') structures in OC asteroids (wherein the degree of metamorphism increases with depth), but the evidence for such structures is weak. It seems likely that collisional heating played an important role in metamorphosing chondritic asteroids.

  16. Petrology and Cosmochemistry of a Suite of R Chondrites

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  17. Petrologic Regime Diagrams: Parameterizing Kinetic Controls on Vesiculation and Crystallization

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.

    2014-12-01

    Regime diagrams are commonly employed in geophysical fluid dynamics to classify experimental results and, ideally, to define non-dimensional parameters that allow those results to be applied to natural systems. Petrologic experiments, in contrast, are typically run to mimic a specific natural system, and to infer conditions of magma storage, cooling or decompression. This approach has produced important insight into specific volcanoes, but the results are difficult to generalize. Additionally, very few experimental studies evaluate the vesiculation, crystallization and degassing histories of the same sample suite, an omission that is understandable given the time-consuming nature of the experiments and analysis, but which leaves important gaps in our general understanding of the interplay between gas exsolution, crystal formation and eruption dynamics. One way to bridge these gaps is to construct a regime diagram for conditions of vesiculation and crystallization. As both are controlled by the effective supercooling experienced by the magma during cooling or decompression, one key parameter is supersaturation, although in practice, decompression rate (cooling rate) are commonly used as proxies for supersaturation. Vesiculation and crystallization are also modulated by diffusion (dependent on individual species and melt viscosity), which can be simply approximated by melt composition. Using these parameters and published data for water-saturated decompression experiments, the following fields can be (partially) defined: (1) non-equilibrium volatile exsolution, (2) equilibrium volatile exsolution, and (3) exsolution accompanied by crystallization. Melt compositions, volatile contents and crystal textures of natural samples can be measured, and thus related (crudely) to the regime diagram. Additional information required for fully linking experiments and volcanic pyroclasts includes phase proportions (crystallization efficiency), pyroclast textures (phase change

  18. Petrology of the Crystalline Rocks Hosting the Santa Fe Impact Structure

    NASA Technical Reports Server (NTRS)

    Schrader, C. M.; Cohen, B. A.

    2010-01-01

    We collected samples from within the area of shatter cone occurrence and for approximately 8 kilometers (map distance) along the roadway. Our primary goal is to date the impact. Our secondary goal is to use the petrology and Ar systematics to provide further insight into size and scale of the impact. Our approach is to: Conduct a detailed petrology study to identify lithologies that share petrologic characteristics and tectonic histories but with differing degrees of shock. Obtain micro-cores of K-bearing minerals from multiple samples for Ar-40/Ar-39 analysis. Examine the Ar diffusion patterns for multiple minerals in multiple shocked and control samples. This will help us to better understand outcrop and regional scale relationships among rocks and their responses to the impact event.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  20. The Genesis of Chua's Circuit:. Connecting Science, Art and Creativity

    NASA Astrophysics Data System (ADS)

    Bertacchini, Francesca; Bilotta, Eleonora; Laria, Giuseppe; Pantano, Pietro

    2013-01-01

    The Chua's circuit has provided science with a real scientific and technological advancement in the field of dynamical systems. But the origin of the Chua's circuit, which has resulted in major areas of study within Chaos Theory, with thousands of printed scientific articles, is not widely known. In this chapter, we trace the fundamental stages of the Genesis of the Chua's circuit. To make the story more appealing for the new generations, a 3D movie was made (issued on DVD, with this volume). Besides presenting the main characters from the history of such system, it also introduces Lorenz, Poincare, Julia and Cantor as the precursors of the studies on chaos, which discuss the need for a physical system that demonstrates chaos, a phenomenon not yet understood, in a numerical, physical and experimental way. The story, enriched by the conversations of the above mentioned characters, was staged exactly as it occurred, derived from Professor Chua's famous article of 1983, The Genesis of the Chua's circuit. And the story continues with the authors contribution in expanding Chaos Theory, with the discovery of almost one thousand attractors, which have provided new important elements for the advancement of science in the field of nonlinear chaotic systems.

  1. Genesis of transverse kame trains in eastern Poland

    NASA Astrophysics Data System (ADS)

    Terpiłowski, Sławomir

    2007-01-01

    Transverse kames, forming trains perpendicular to the direction of ice-sheet advance, are rare morphological elements in previously glaciated areas. The genesis of an example from the ice-contact zone of the Wartanian glaciation in eastern Poland is discussed. The transverse kames there form two main, distinctly separated, sub-parallel trains. Their sedimentary successions fill erosional troughs incised in the pre-Wartanian deposits on northern slopes. They consist of thick glaciofluvial sand and glaciofluvial/glaciolacustrine sandy/silty units that are covered with a thin, usually discontinuous, glacial till succession. The genesis of this kame type has been modelled. It is concluded that transverse kames developed in two phases: (1) erosion of the substratum in subglacial channels during initial deglaciation, and (2) glaciofluvial deposition in crevasses during advanced deglaciation (in the form of low-energy fans periodically submerged under stagnant water), followed locally by a cover of flowtills. Both the ablation of the ice and the accumulation of the kame deposits were controlled by the co-occurrence of ice zones either enriched or impoverished with sediment. Zonal enrichment of ice with debris was determined by the development of shear zones over substratum elevations that were inclined up-ice. The formation and subsequent infilling of crevasses both took place in zones of relatively clean ice, so that the resulting kames form a train perpendicular to the direction of ice movement.

  2. Laser Subdivision of the Genesis Concentrator Target Sample 60000

    NASA Technical Reports Server (NTRS)

    Lauer, Howard V., Jr.; Burkett, P. J.; Rodriquez, M. C.; Nakamura-Messenger, K.; Clemett, S. J.; Gonzales, C. P.; Allton, J. H.; McNamara, K. M.; See, T. H.

    2013-01-01

    The Genesis Allocation Committee received a request for 1 square centimeter of the diamond-like-carbon (DLC) concentrator target for the analysis of solar wind nitrogen isotopes. The target consists of a single crystal float zone (FZ) silicon substrate having a thickness on the order of 550 micrometers with a 1.5-3.0 micrometer-thick coating of DLC on the exposed surface. The solar wind is implanted shallowly in the front side DLC. The original target was a circular quadrant with a radius of 3.1 cm; however, the piece did not survive intact when the spacecraft suffered an anomalous landing upon returning to Earth on September 8, 2004. An estimated 75% of the DLC target was recovered in at least 18 fragments. The largest fragment, Genesis sample 60000, has been designated for this allocation and is the first sample to be subdivided using our laser scribing system Laser subdivision has associated risks including thermal diffusion of the implant if heating occurs and unintended breakage during cleavage. A careful detailed study and considerable subdividing practice using non-flight FZ diamond on silicon, DOS, wafers has considerably reduced the risk of unplanned breakage during the cleaving process. In addition, backside scribing reduces the risk of possible thermal excursions affecting the implanted solar wind, implanted shallowly in the front side DLC.

  3. Examples of Optical Assessment of Surface Cleanliness of Genesis Samples

    NASA Technical Reports Server (NTRS)

    Rodriquez, Melissa C.; Allton, J. H.; Burkett, P. J.; Gonzalez, C. P.

    2013-01-01

    Optical microscope assessment of Genesis solar wind collector surfaces is a coordinated part of the effort to obtain an assessed clean subset of flown wafer material for the scientific community. Microscopic survey is typically done at 50X magnification at selected approximately 1 square millimeter areas on the fragment surface. This survey is performed each time a principle investigator (PI) returns a sample to JSC for documentation as part of the established cleaning plan. The cleaning plan encompasses sample handling and analysis by Genesis science team members, and optical survey is done at each step in the process. Sample surface cleaning is performed at JSC (ultrapure water [1] and UV ozone cleaning [2]) and experimentally by other science team members (acid etch [3], acetate replica peels [4], CO2 snow [5], etc.). The documentation of each cleaning method can potentially be assessed with optical observation utilizing Image Pro Plus software [6]. Differences in particle counts can be studied and discussed within analysis groups. Approximately 25 samples have been identified as part of the cleaning matrix effort to date.

  4. Nano-inclusions in diamond: Evidence of diamond genesis

    NASA Astrophysics Data System (ADS)

    Wirth, R.

    2015-12-01

    The use of Focused Ion Beam technology (FIB) for TEM sample preparation introduced approximately 15 years ago revolutionized the application of TEM in Geosciences. For the first time, FIB enabled cutting samples for TEM use from exactly the location we are interested in. Applied to diamond investigation, this technique revealed the presence of nanometre-sized inclusions in diamond that have been simply unknown before. Nanoinclusions in diamond from different location and origin such as diamonds from the Lower and Upper Mantle, metamorphic diamonds (Kazakhstan, Erzgebirge, Bohemia), diamonds from ophiolites (Tibet, Mongolia, Xinjiang, Ural Mountains), diamonds from igneous rocks (Hawaii, Kamchatka) and impact diamonds (Popigai Crater, Siberia) have been investigated during the last 15 years. The major conclusion of all these TEM studies is, that the nanoinclusions, their phases and phase composition together with the micro- and nanostructure evidence the origin of diamond and genesis of diamond. We can discriminate Five different mechanisms of diamond genesis in nature are observed: Diamond crystallized from a high-density fluid (Upper mantle and metamorphic diamond). Diamond crystallized from carbonatitic melt (Lower mantle diamond). Diamond precipitates from a metal alloy melt (Diamond from ophiolites). Diamond crystallized by gas phase condensation or chemical vapour condensation (CVD) (Lavas from Kamchatka, xenoliths in Hawaiian lavas). Direct transformation of graphite into diamond.

  5. Dynamic Stability Testing of the Genesis Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Cheatwood, F. McNeil; Winchenbach, Gerald L.; Hathaway, Wayne; Chapman, Gary

    2000-01-01

    This paper documents a series of free flight tests of a scale model of the Genesis Sample Return Capsule. These tests were conducted in the Aeroballistic Research Facility (ARF), located at Eglin AFB, FL, during April 1999 and were sponsored by NASA Langley Research Center. Because these blunt atmospheric entry shapes tend to experience small angle of attack dynamic instabilities (frequently leading to limit cycle motions), the primary purpose of the present tests was to determine the dynamic stability characteristics of the Genesis configuration. The tests were conducted over a Mach number range of 1.0 to 4.5. The results for this configuration indicate that the models were dynamically unstable at low angles of attack for all Mach numbers tested. At Mach numbers below 2.5, the models were also unstable at the higher angles of attack (above 15 deg), and motion amplitudes of up to 40 deg were experienced. Above Mach 2.5, the models were dynamically stable at the higher angles of attack.

  6. Constraints on chondrule origin from petrology of isotopically characterized chondrules in the Allende meteorite

    NASA Astrophysics Data System (ADS)

    McSween, H. Y., Jr.

    1985-09-01

    The petrologic and chemical properties of the ferromagnesian chondrules in the Allende carbonaceous chondrite were examined in terms of the isotopic composition and the correlations between isotopic patterns. Areas of thin sections were studied with a SEM and bulk chemical fractions of 12 constituents were quantified to calculate correlations with petrologic features. A possible correlation between (CaO + Al2O2)/MgO and oxygen isotopes imply the formation of oxygen isotopic compositions in the chondrules by exchanges between isotopically heavy nebular gases and O-16 enriched solids. Different rates of gaseous exchange occurred with the various types of chondrules. Factors which may have controlled the exchanges are discussed.

  7. Constraints on chondrule origin from petrology of isotopically characterized chondrules in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Mcsween, H. Y., Jr.

    1985-01-01

    The petrologic and chemical properties of the ferromagnesian chondrules in the Allende carbonaceous chondrite were examined in terms of the isotopic composition and the correlations between isotopic patterns. Areas of thin sections were studied with a SEM and bulk chemical fractions of 12 constituents were quantified to calculate correlations with petrologic features. A possible correlation between (CaO + Al2O2)/MgO and oxygen isotopes imply the formation of oxygen isotopic compositions in the chondrules by exchanges between isotopically heavy nebular gases and O-16 enriched solids. Different rates of gaseous exchange occurred with the various types of chondrules. Factors which may have controlled the exchanges are discussed.

  8. Petrology of the Woods Mountains volcanic center, San Bernardino County, California

    SciTech Connect

    McCurry, M.O.

    1985-01-01

    The main purpose of this study is to investigate magma chamber processes through a petrological study of a large, newly examined silicic volcanic center. A characterization of the volcanic center was obtained through a combination of detailed mapping, petrography, analyses of bulk major and trace elements, and microprobe analyses of phenocryst phases. Cooperative studies were undertaken which included geophysical surveys of the center, Nd-Sm and Rb-Sr isotopic systematics and K-Ar dating of the rocks. The volcanic center began at 16.4 mybp with the incremental extrusion of ca 10 km/sup 3/ of dominantly mildly peraluminous dacitic and rhyolitic magma. At 15.5 mybp 870 km/sup 3/ of metaluminous to mildly peraluminous, dominantly rhyolitic pyroclastic flows were extruded, causing the formation of a 10 km diameter caldera. This was followed from 15.5 my to 14.8 my by the incremental, intracaldera extrusion of ca 10 km/sup 3/ of metaluminous to mildly peralkaline, high silica rhyolite magma. A model of magma chamber evolution is presented as follows: (1) a thermal pulse into the base of the crust initiated partial melting of a garnet-biotite gneiss at ca 17 mybp; (2) anatectic pockets of melt of dacitic composition intruded into the upper crust; (3) an increased flux of magma at 16 mybp resulted in the formation of a large magma chamber that evolved a cap of rhyolitic magma by a fractional crystallization within counter buoyant boundary layers; (4) a decay of input into the chamber occurred soon afterward, however chemical potential gradients induced by the rapid extrusion of a large part of the rhyolitic cupola resulted in strong volatile-complex diffusion, forming a thin cap of mildly peralkaline rhyolitic magma.

  9. Geological and Petrological Characteristics of Oligocene Magmatic Rocks in The Biga Peninsula, NW Turkey

    NASA Astrophysics Data System (ADS)

    Erenoglu, Oya

    2016-04-01

    Oligocene magmatic activity in the Biga Peninsula (NW-Anatolia) produced widespread volcano-plutonic complexes. The study region, where in north of the Evciler village in the middle of Biga Peninsula includes these igneous assemblages. In this study, the petrographic and geochemical characteristics of igneous rocks in the region were investigated as well as the geological locations. The magmatic rocks are classified as 6 different units using their lithostratigraphical properties. The volcanism in the region starts with basaltic andesite lava including basalt dykes in the Lower Oligocene. In the Upper Oligocene, the evolved magma by crustal contamination produced commonly dacitic and andesitic lavas. The volcanism continued with andesitic lavas which had significant alterations in the region during this period. Evciler pluton including granite and granodiorite composition with shallow intrusive, was located with the related volcanism at the same time. The volcanic products, i.e. andesitic and trachydacitic lavas, was completed in the interval between Upper Oligocene and Lower Miocene. The post-collisional Oligocene sequence is associated with calc-alkaline composition and it has middle, high-K. Trace and rare earth elements (REE) diagrams show the enrichment in both large-ion lithophile elements (LILE) and light rare earth elements (LREE) with respect to the high field strength elements (HFSE), and a significant increment in heavy rare earth element consumption (HREE). The features of major, trace and rare earth elements of plutonic and volcanic rocks and the compositional variations of Oligocene volcanic group indicate increasing amounts of partial melting, crustal contamination and/or assimilation. The Oligocene post-collisional volcanism in Biga Peninsula points out the lithospheric mantle source enriched by subduction which controlled by slab break-off and lithospheric delamination. Acknowledgement. This study was supported by Canakkale Onsekiz Mart University

  10. Petrology and provenance of Upper Cretaceous Sandstone, southern San Rafael Mountains, Santa Barbara County, California

    SciTech Connect

    Toyne, C.D.

    1987-05-01

    Petrologic analysis of 24 medium to coarse-grained sandstone samples, collected from a 2950-m submarine fan complex of late Campanian-early Maestrichtian age exposed within Mono Creek Canyon, reveal commonly calcite cemented, poorly sorted, subangular biotic arkoses. Framework averages 86.0%. Matrix - primarily detrital quartz, feldspar, and lithic fragments finer than 0.03 mm and mechanically and chemically altered phyllosilicates and labile aphanites - averages 8.9%. Calcite cement averages 4.2%. Porosity averages 0.9%. Gazzi-Dickinson point counts of 400 framework grains per slide yield modal averages of Q/sub 37.7/ F/sub 49.8/ L/sub 12.5/; Qm/sub 27.4/ F/sub 49.8/ Lt/sub 22.8/; Qm/sub 35.6/ P/sub 43.7/ K/sub 20.7/; and Qp/sub 49.4/ Lv/sub 22.1/ Ls/sub 28.5/. P/F averages 0.68, Lv/L averages 0.45, Qp/Q averages 0.27, and detrital phyllosilicate, predominantly biotite, averages 5.7% of total framework. Neither primary nor secondary parameters vary systematically with stratigraphic position. Miscellaneous constituents average 1.3% of framework and include epidote, garnet, amphibole, pyroxene, zircon, and tourmaline as well as carbonaceous blebs, opaque minerals, and unidentifiable lithic fragments. Separate analysis of 100 medium sized quartz grains per slide indicates a mean population of 63.0% non-undulatory monocrystalline quartz, 9.1% undulatory monocrystalline quartz, 10.1% polycrystalline quartz of 2 to 3 crystals, and 17.9% polycrystalline quartz composed of more than 3 crystals. Modal data, plotted upon provenance discrimination diagrams, indicate a plutonic provenance transitional between a dissected magmatic arc and uplifted basement terrane. Paleocurrent data, neglecting possible clockwise rotation, indicate sediment transport from the north.

  11. The petrology and geochemistry of a metabasite belt along the southern margin of Alaska

    PubMed Central

    Bruand, E.; Gasser, D.; Bonnand, P.; Stuewe, K.

    2011-01-01

    A 600 km long metabasite belt is exposed at the southern border of the Chugach terrane in southern Alaska, south of the Eocene Chugach Metamorphic Complex (CMC). In this contribution, we present petrologic and geochemical results for parts of this metabasite belt. The metabasites studied are amphibolite grade and their PT conditions are evaluated with hornblende–plagioclase thermometry and the average PT method. From west to east the peak metamorphic conditions calculated are: about 730–793 °C for pressures between 5 and 15 kbar in the westernmost part, about 740–760 °C and 5 kbar in the middle locality and about 640–675 °C and 8 kbar in the easternmost locality. These results are comparable with the metamorphic conditions obtained on metapelite of the CMC for the westernmost and easternmost localities. In contrast, in the central part of the CMC, the metabasites experienced probably lower pressures than the metapelites to the north. Rare earth and trace element patterns of the metabasite belt are comparable with typical altered basalt patterns and reveal MORB and arc-tholeiitic geochemical characteristics. The presence of Ba and U anomalies are interpreted as a result of alteration prior to subduction, the Pb anomaly as a result of an intra-oceanic island arc signature and the Sr anomaly as a result of the interaction of sediments with the metabasites during subduction. We suggest that the association of MORB and arc tholeiitic rocks in the metabasite belt is likely derived from an intra-oceanic island arc which accreted to the Alaskan margin. PMID:26523072

  12. Genesis Concentrator Target Particle Contamination Mapping and Material Identification

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Rodriquez, M. C.; Allton, J. H.

    2007-01-01

    The majority of surface particles were found to be < 5 microns in diameter with increasing numbers close to the optical resolution limit of 0.3 microns. Acceleration grid EDS results show that the majority of materials appear to be from the SRC shell and SLA materials which include carbon-carbon fibers and Si-rich microspheres in a possible silicone binder. Other major debris material from the SRC included white paint, kapton, collector array fragments, and Al. Image analysis also revealed that SRC materials were also found mixed with the Utah mud and salt deposits. The EDS analysis of the acceleration grid showed that particles < 1 m where generally carbon based particles. Chemical cleaning techniques with Xylene and HF in an ultrasonic bath are currently being investigated for removal of small particles by the Genesis science team as well as ultra-pure water megasonic cleaning by the JSC team [4]. Removal of organic contamination from target materials is also being investigated by the science team with the use of UV-ozone cleaning devices at JSC and Open University [5]. In preparation for solar wind oxygen analyses at UCLA and Open University [1, 2], surface particle contamination on three Genesis concentrator targets was closely examined to evaluate cleaning strategies. Two silicon carbide (Genesis sample # 60001 and 60003) and one chemical vapor deposited (CVD) 13C concentrator target (60002) were imaged and mosaic mapped with optical microscopes. The resulting full target mosaic images and particle feature maps were subsequently compared with non-flight, but flight-like, concentrator targets and sample return capsule (SRC) materials. Contamination found on the flown concentrator acceleration grid was further examined using a scanning electron microscope (SEM). Energy dispersive X-ray spectroscopy (EDS) for particle identification was subsequently compared with the optical images from the flown targets. Figure 1 show that all three targets imaged in this report

  13. Bases of the Mantle-Carbonatite Conception of Diamond Genesis

    NASA Astrophysics Data System (ADS)

    Litvin, Yuriy; Spivak, Anna; Kuzyura, Anastasia

    2016-04-01

    In the mantle-carbonatite conception of diamond genesis, the results of physic-chemical experiments are coordinated with the data of analytic mineralogy of primary inclusions in natural diamonds. Generalization of the solutions of principal genetic problems constitutes the bases of the conception. The solutions are following: (1) it is grounded that diamond-parental melts of the upper mantle have peridotite/eclogite - carbonatite - carbon compositions, of the transition zone - (wadsleite↔ringwoodite) - majorite - stishovite - carbonatite - carbon compositions, and of the lower mantle - periclase/wustite - bridgmanite - Ca-perovskite -stishovite - carbonatite - carbon compositions; (2) a construction of generalized diagrams for the diamond-parental media, which reveal changeable compositions of the growth melts of diamonds and associated phases, their genetic relations to the mantle substance, and classification connections of the primary inclusions in natural diamonds; (3) experimental equilibrium phase diagrams of syngenesis of diamonds and primary inclusions, which characterize the nucleation and growth conditions of diamonds and a capture of paragenetic and xenogenetic minerals by the growing diamonds; (4) a determination of the phase diagrams of diamonds and inclusions syngenesis under the regime of fractional crystallization, which discover the regularities of ultrabasic-basic evolution and paragenesis transitions in the diamond-forming systems of the upper and lower mantle. The evidence of the physic-chemically united mode of diamond genesis at the mantle depths with different mineralogy is obtained. References. Litvin Yu.A. (2007). High-pressure mineralogy of diamond genesis. In: Advances in High-Pressure Mineralogy (edited by Eiji Ohtani), Geological Society of America Special paper 421, 83-103. Litvin Yu.A. (2012). Experimental study of physic-chemical conditions of natural diamond formation on an example of the eclogite

  14. Eruptive stratigraphy of the Tatara-San Pedro complex, 36°S, sourthern volcanic zone, Chilean Andes: reconstruction method and implications for magma evolution at long-lived arc volcanic centers

    USGS Publications Warehouse

    Dungan, M.A.; Wulff, A.; Thompson, R.

    2001-01-01

    The Quaternary Tatara-San Pedro volcanic complex (36°S, Chilean Andes) comprises eight or more unconformity-bound volcanic sequences, representing variably preserved erosional remnants of volcanic centers generated during 930 ky of activity. The internal eruptive histories of several dominantly mafic to intermediate sequences have been reconstructed, on the basis of correlations of whole-rock major and trace element chemistry of flows between multiple sampled sections, but with critical contributions from photogrammetric, geochronologic, and paleomagnetic data. Many groups of flows representing discrete eruptive events define internal variation trends that reflect extrusion of heterogeneous or rapidly evolving magna batches from conduit-reservoir systems in which open-system processes typically played a large role. Long-term progressive evolution trends are extremely rare and the magma compositions of successive eruptive events rarely lie on precisely the same differentiation trend, even where they have evolved from similar parent magmas by similar processes. These observations are not consistent with magma differentiation in large long-lived reservoirs, but they may be accommodated by diverse interactions between newly arrived magma inputs and multiple resident pockets of evolved magma and / or crystal mush residing in conduit-dominated subvolcanic reservoirs. Without constraints provided by the reconstructed stratigraphic relations, the framework for petrologic modeling would be far different. A well-established eruptive stratigraphy may provide independent constraints on the petrologic processes involved in magma evolution-simply on the basis of the specific order in which diverse, broadly cogenetic magmas have been erupted. The Tatara-San Pedro complex includes lavas ranging from primitive basalt to high-SiO2 rhyolite, and although the dominant erupted magma type was basaltic andesite ( 52-55 wt % SiO2) each sequence is characterized by unique proportions of

  15. Petrology of enstatite chondrites and anomalous enstatite achondrites

    NASA Astrophysics Data System (ADS)

    van Niekerk, Deon

    2012-01-01

    . The broad importance of these studies lies in documenting the petrology of extraterrestrial materials that reveal the geological history of the young solar system prior to the existence of planets. Furthermore, they serve to identify which mineral assemblages record nebular processes and which record processes on asteroids, so that future studies may select the correct material to address particular questions.

  16. The connection between crustal reworking and petrological diversity in the deep crust: clues from migmatites

    NASA Astrophysics Data System (ADS)

    Carvalho, Bruna B.; Sawyer, Edward W.; de Assis Janasi, Valdecir

    2016-04-01

    The deep levels of the continental crust have been extensively reworked as result of crustal differentiation. Migmatites are widespread in these high-grade metamorphic terrains, and provide valuable information on how processes such as partial melting, segregation of the melt from the residue and subsequent chemical exchanges lead to the petrological diversity found in the deep crust. This study investigates processes that transformed a largely uniform, metagranodiorite protolith into a very complex migmatite that contains three varieties of diatexites (grey, schlieren and homogenous diatexites) and several types of leucosomes. The Kinawa Migmatite is part of the Archean TTG crust in the São Francisco Craton (Brazil), which has been reworked in a shear zone environment at upper amphibolite facies conditions (<730°C and 5-6 kbar); thus it may be typical of crustal reworking in the interior of old cratons [1]. Grey diatexites are residual rocks formed by the extraction of a water-fluxed melt created via the reaction Pl + Kfs + Qz + H2O = melt. Diversity within the grey diatexites arises from different degrees of melt segregation (maximum ~40% melt). Schlieren diatexites are very heterogeneous rocks in which residuum-rich domains alternate with leucocratic quartzo-feldspathic domains where melt accumulated. Homogeneous diatexites are coarse-grained leucocratic rocks and represent larger bodies of anatectic melt with minor amounts (<20%) of entrained residuum. Leucosomes display a wide range of compositions from tonalitic to alkali-feldspar granite. Leucosomes, homogeneous diatexites and the quartzo-feldspathic domains in the schlieren diatexites all show a sequence of microstructural stages from plagioclase-dominated to K-feldspar-dominated frameworks many of which show evidence for tectonic compaction. Thus, further segregation of melt from solids occurred during crystallization. Minor amphibolite dykes in the metagranodiorite did not melt. They occur as angular to

  17. Genesis Solar Wind Sample Curation: A Progress Report

    NASA Technical Reports Server (NTRS)

    Allton, Judith H.; Calaway, M. J.; Rodriquez, M. C.; Hittle, J. D.; Wentworth, S. J.; Stansbery, E. K.; McNamara, K. M.

    2006-01-01

    In the year since the Genesis solar wind collector fragments were returned, early science samples, specimens for cleaning experiments, and science allocations have been distributed. Solar wind samples are stored under nitrogen and handled in an ISO Class 4 (Class 10) laboratory. For array collector fragments, a basic characterization process has been established. This characterization consists of identification of solar wind regime, whole fragment image for identification and surface quality, higher magnification images for contaminant particle density, and assessment of molecular film contaminant thickness via ellipsometry modeling. Compilations of this characterization data for AuOS (gold film on sapphire), and sapphire from the bulk solar wind for fragments greater than 2 cm are available. Removal of contaminant particles using flowing ultrapure water (UPW) energized megasonically is provided as requested.

  18. The Genesis of Meteorology at the University of Chicago.

    NASA Astrophysics Data System (ADS)

    Allen, Douglas R.

    2001-09-01

    The genesis of meteorology at the University of Chicago is reviewed in commemoration of the 60th anniversary of the founding of the Institute of Meteorology. The Institute of Meteorology was founded in October 1940 under the leadership of Carl Rossby and Horace Byers. Although previous attempts failed due to lack of resources, the imminent need for meteorologists in aviation and long-range weather forecasting, particularly for the nation's military needs, provided sufficient motivation for the program, and a $15,000 donation by Sewell Avery provided the necessary funds to get the program started. This article adds to Byers' 1975 account of the founding of the Institute by documenting the exchange of letters in 1939 between C. Rossby, Karl T. Compton (president of Massachusetts Institute of Technology), Arthur H. Compton (professor of Physics at Chicago), and Henry Gale (dean of Physical Sciences at Chicago) regarding the possibility of establishing a meteorology program at Chicago.

  19. Genesis of Atlantic Lows Experiment (GALE) - An overview

    NASA Technical Reports Server (NTRS)

    Dirks, R. A.; Kuettner, J. P.; Moore, J. A.

    1988-01-01

    The field phase of the Genesis of Atlantic Lows Experiment (GALE) was conducted from 15 January to 15 March 1986. The objectives of GALE were to study mesoscale and air-sea interaction processes in East Coast winter storms, with particular emphasis on their contributions to cyclogenesis. This project area, specail observing systems, and field operations are described. There were thirteen special observing periods during the field phase including eight cases of cyclogenesis. Meterological and oceanographic phenomena on which special observations were collected include: cyclogenesis, rainbands, cold fronts, coastal fronts, cold-air damming, jets streaks, tropopause folding, low-level jets, cold-air outbreaks, lightning and marine boundary layer interactions with Gulf Stream and mid-shelf oceanic fronts. Preliminary research findings and operational implications are presented. GALE data documents are listed. The GALE data set is open to all interested scientists.

  20. Satellite Observations Defying the Long-Held Tsunami Genesis Theory

    NASA Astrophysics Data System (ADS)

    Song, Y.; Han, S.

    2009-12-01

    Using seismographs and GPS displacement measurements, we have fully estimated the seafloor deformation history of the December 2004 Sumatra-Andaman earthquake and the March 2005 Nias Island earthquake by separating their deformation period into intervals of 800-sec, 1-hour, and 6-months. Their corresponding gravity changes (induced by the seafloor deformation) are 11.3, 12.5, and 14.9 microgalileo, respectively, consistent with the Gravity Recovery and Climate Experiment (GRACE) satellites measurements of 15 microgalileo for the same period of six months. However, the vertical component of the accumulated seafloor deformation during the tsunami formation period could only generate a potential energy of 1.2E+15 Joules and account for only one third of the actual tsunami height measured by altimeters. The evidence is overwhelmingly contrary to the long-held theory that the vertical deformation of seafloor is the primary source of tsunamis. Surprisingly, we also found that a pioneering wave-maker experiment, which conceived the vertically-forced tsunami genesis theory in 1980s, used an exaggerated experimental ratio of the horizontal slip distance to the water depth, the key non-dimensional parameter that allows comparing the experiment with reality on an apple-to-apple basis, about 200 times of realistic earthquake parameters. The experiment is problematic in conceiving the vertically-forced tsunami theory. We conclude that the tsunami source has been poorly understood and the tsunami formation mechanism is not as simple as previously thought. Our study suggests a new method of using gravity measurement from space to constrain the under-sea earthquake source for tsunami modeling and to gain insight into the tsunami genesis theory. Seafloor deformation, corresponding gravity changes, and GRACE measurements of the December 26 Sumatra-Andaman earthquake and the March 2005 Nias Island earthquake.

  1. Detecting Tsunami Genesis and Scales Directly from Coastal GPS Stations

    NASA Astrophysics Data System (ADS)

    Song, Y. Tony

    2013-04-01

    Different from the conventional approach to tsunami warnings that rely on earthquake magnitude estimates, we have found that coastal GPS stations are able to detect continental slope displacements of faulting due to big earthquakes, and that the detected seafloor displacements are able to determine tsunami source energy and scales instantaneously. This method has successfully replicated several historical tsunamis caused by the 2004 Sumatra earthquake, the 2005 Nias earthquake, the 2010 Chilean earthquake, and the 2011 Tohoku-Oki earthquake, respectively, and has been compared favorably with the conventional seismic solutions that usually take hours or days to get through inverting seismographs (reference listed). Because many coastal GPS stations are already in operation for measuring ground motions in real time as often as once every few seconds, this study suggests a practical way of identifying tsunamigenic earthquakes for early warnings and reducing false alarms. Reference Song, Y. T., 2007: Detecting tsunami genesis and scales directly from coastal GPS stations, Geophys. Res. Lett., 34, L19602, doi:10.1029/2007GL031681. Song, Y. T., L.-L. Fu, V. Zlotnicki, C. Ji, V. Hjorleifsdottir, C.K. Shum, and Y. Yi, 2008: The role of horizontal impulses of the faulting continental slope in generating the 26 December 2004 Tsunami, Ocean Modelling, doi:10.1016/j.ocemod.2007.10.007. Song, Y. T. and S.C. Han, 2011: Satellite observations defying the long-held tsunami genesis theory, D.L. Tang (ed.), Remote Sensing of the Changing Oceans, DOI 10.1007/978-3-642-16541-2, Springer-Verlag Berlin Heidelberg. Song, Y. T., I. Fukumori, C. K. Shum, and Y. Yi, 2012: Merging tsunamis of the 2011 Tohoku-Oki earthquake detected over the open ocean, Geophys. Res. Lett., doi:10.1029/2011GL050767 (Nature Highlights, March 8, 2012).

  2. Posthemorrhagic antipyresis: what stage of fever genesis is affected?

    PubMed

    Romanovsky, A A; Karman, Y K

    1997-08-01

    It has been shown that hemorrhage leads to a decreased thermal responsiveness to lipopolysaccharide (LPS). The aim of this study was to clarify what stage of fever genesis [production of endogenous pyrogens such as interleukin-1 (IL-1), increase of the prostaglandin E2 (PGE2) concentration in brain tissue, activation of cold-defense effectors] is deficient in posthemorrhagic antipyresis. In adult rabbits, we evaluated the effect of acute hemorrhage (15 ml/kg) on the rectal temperature (Tre) responses to LPS from Salmonella typhi (200 ng/kg iv), ethanol-purified preparation of homologous IL-1 (1 ml from 3.5 x 10(7) cells, 1.5 ml/kg iv), and PGE2 (1 microg, intracisternal injection). The effect of hemorrhage on Tre was also studied in afebrile rabbits, both at thermoneutrality (23 degrees C) and during ramp cooling (to 7 degrees C). The hemorrhage strongly attenuated the biphasic LPS-induced fever (a Tre rise of 0.4 +/- 0.1 instead of 1.2 +/- 0.2 degrees C at the time of the second peak), the monophasic Tre response to IL-1 (by approximately 0.5 degrees C for over 1-5 h postinjection), and the PGE2-induced hyperthermia (0.4 +/- 0.1 vs. 0.9 +/- 0.1 degrees C, maxima). In afebrile animals, the hemorrhage neither affected Tre at thermoneutrality nor changed the Tre response to cold exposure. The data suggest that neither insufficiency of cold-defense effectors nor lack of endogenous mediators of fever (IL-1, PGE2) can be the only or even the major cause of posthemorrhagic antipyresis. We speculate that fever genesis is altered at a stage occurring after the intrabrain PGE2 level is increased but before thermoeffectors are activated. PMID:9262427

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  4. Petrology and Geochemistry of Lunar Meteorite Abar al'Uj 012

    NASA Astrophysics Data System (ADS)

    Mészáros, M.; Hofmann, B. A.; Korotev, R. L.; Gnos, E.; Greber, N.; Greenwood, R. C.

    2014-09-01

    The petrology and geochemistry of Abar al’Uj 012, a feldspathic lunar meteorite found in Saudi Arabia is described. The meteorite is a vesicular crystalline impact-melt breccia, which lacks a fusion crust and has a ferroan anorthosite affinity.

  5. Unmixing the SNCs: Chemical, Isotopic, and Petrologic Components of the Martian Meteorites

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This volume contains abstracts that have been accepted for presentation at the conference on Unmixing the SNCs: Chemical, Isotopic, and Petrologic Components of Martian Meteorites, September 11-12, 2002, in Houston, Texas. Administration and publications support for this meeting were provided by the staff of the Publications and Program Services Department at the Lunar and Planetary Institute.

  6. RIMS analysis of Ca and Cr in genesis solar wind collectors.

    SciTech Connect

    Veryovkin, I. V.; Tripa, C. E.; Zinovev, A. V.; King, B. V.; Pellin, M. J.; Burnett, D. S.; Materials Science Division; Univ. of Newcastle; California Inst. of Tech.

    2011-01-01

    RIMS depth profiles have been measured for Cr and Ca in Genesis solar wind collector made from Si and compared to such measurements for ion-implanted Si reference material. The presence of surface contamination has been shown to be a significant factor influencing the total Ca and Cr fluence measured in the Genesis collectors. A procedure to remove the contaminant signal from these depth profiles using the reference material implanted with a minor isotope demonstrated that 36% of the measured Ca fluence in our Genesis sample comes from terrestrial contamination.

  7. Data-driven Science in Geochemistry & Petrology: Vision & Reality

    NASA Astrophysics Data System (ADS)

    Lehnert, K. A.; Ghiorso, M. S.; Spear, F. S.

    2013-12-01

    measurements, experiments, and models, both from past and from present studies, and their poor discoverability, interoperability, and standardization. Other deficiencies include the lack of widespread sample curation and online sample catalogs, and broad community support and enforcement of open data sharing policies and a strategy for sustained funding and operation of the cyberinfrastructure. In order to achieve true data-driven science in geochemistry and petrology, one of the primary requirements is to change the way data and models are managed and shared to dramatically improve their access and re-usability. Adoption of new data publication practices, new ways of citing data that ensure attribution and credit to authors, tools that help investigators to seamlessly manage their data throughout the data life cycle, from the point of acquisition to upload to repositories, and population of databases with historical data are among the most urgent needs. The community, especially early career scientists, must work together to produce the cultural shift within the discipline toward sharing of data and knowledge, virtual collaboration, and social networking. Dziewonski, A M, & Anderson, D L: Physics of the Earth and Planet Interiors 25 (4), 297 (1981) Hey, T, Tansley, S, Tolle, K (Eds.): Redmond, VA: Microsoft Research (2009) Zindler, A, & Hart, S R: Ann. Rev. Earth Plan. Sci. 14, 493 (1986)

  8. Partial crystallization of picritic melt and its applications for the genesis of high-Ti and low-Ti basalts

    NASA Astrophysics Data System (ADS)

    Yang, J.; WANG, C.; Jin, Z.; Jin, S.; Yan, S.

    2015-12-01

    Geochemical and petrological studies have revealed the existence of high-Ti and low-Ti basalts in large igneous provinces (LIPs). However the originate of these high-Ti and low-Ti magmas are still under debate. Several different mechanisms have been proposed: (1) the high-Ti basalts are formed by the melting of mantle plume containing recycled oceanic crust (Spandler et al., 2008) while low-Ti basalts are formed by the melting of subcontinental lithospheric mantle (Xiao et al., 2004); (2) both high-Ti and low-Ti basalts are from mantle plume source, but the production of high-Ti basalts are associated with the thick lithosphere while the low-Ti basalts are controlled by the thin lithosphere (Arndt et al., 1993); (3) they are derived from the different degrees of melting, with high-Ti basalts representing low degree of partial melting of mantle plume (Xu et al., 2004). The low Mg# (below 0.7) of high-Ti and low-Ti basalts provides that they are far away from direct melting of mantle peridotite. In addition, seismic data indicate unusually high seismic velocities bodies beneath the LIPs which explained by the fractionated cumulates from picritic magmas (Farnetani et al., 1996). Therefore, we believed that the crystallization differentiation process might play a more significant role in the genesis of high-Ti and low-Ti basalts.In order to investigate the generation of high-Ti and low-Ti basalts, a series of high pressure and high temperature partial crystallization experiments were performed at pressures of 1.5, 3.0 and 5.0 GPa and a temperature range of 1200-1700℃. The starting material is picrate glass with relative high TiO2 (2.7 wt %), which is synthesized according to the chemical composition of primary magmas of Emeishan LIP (Xu et al., 2001). The experimental results show that: (1) At a given pressure, the TiO2 content is decreased with increasing melt fraction; (2) At a given melt fraction, the TiO2 content of melts is increased with increasing pressure. On

  9. Maneuver Design and Calibration for the Genesis Spacecraft

    NASA Technical Reports Server (NTRS)

    Williams, Kenneth E.; Hong, Philip E.; Zietz, Richard P.; Han, Don

    2000-01-01

    Genesis is the fifth mission selected as part of NASA's Discovery Program. The objective of Genesis is to collect solar wind samples for a period of approximately two years while in a halo orbit about the Earth-Sun L I point. At the end of this period, the samples are to be returned to a specific recovery point on the Earth for subsequent analysis. This goal has never been attempted before and presents a formidable challenge in terms of mission design and operations, particularly planning and execution of propulsive maneuvers. To achieve a level of cost-effectiveness consistent with a Discovery-class mission, the Genesis spacecraft design was adapted to the maximum extent possible from designs used on earlier missions, such as Mars Global Surveyor (MGS) and Stardust, another sample collection mission. The spacecraft design for Genesis is shown. Spin stabilization was chosen for attitude control, in lieu of three-axis stabilization, with neither reaction wheels nor accelerometers included. This precludes closed-loop control of propulsive maneuvers and implies that any attitude changes, including spin changes and precessions, will behave like translational propulsive maneuvers and affect the spacecraft trajectory. Moreover, to minimize contamination risk to the samples collected, all thrusters were placed on the side opposite the sample collection canister. The orientation and characteristics of thrusters are indicated. For large maneuvers (>2.5 m/s), two 5 lbf thrusters will be used for delta v, with precession to the burn attitude, followed by spin-up from 1.6 to 10 rpm before the burn and spin down to 1.6 rpm afterwards, then precession back to the original spin attitude. For small maneuvers (<2.5 m/s), no spin change is needed and four 0.2 lbf thrusters are used for Av. Single or double 360 deg. precession changes are required whenever the desired delta v falls inside the two-way turn circle (about 0.4 m/s) based on the mass properties, spin rate and lever arm

  10. Magma genesis, storage and eruption processes at Aluto volcano, Ethiopia: lessons from remote sensing, gas emissions and geochemistry

    NASA Astrophysics Data System (ADS)

    Hutchison, William; Biggs, Juliet; Mather, Tamsin; Pyle, David; Gleeson, Matthew; Lewi, Elias; Yirgu, Gezahgen; Caliro, Stefano; Chiodini, Giovanni; Fischer, Tobias

    2016-04-01

    One of the most intriguing aspects of magmatism during the transition from continental rifting to sea-floor spreading is that large silicic magmatic systems develop within the rift zone. In the Main Ethiopian Rift (MER) these silicic volcanoes not only pose a significant hazard to local populations but they also sustain major geothermal resources. Understanding the journey magma takes from source to surface beneath these volcanoes is vital for determining its eruption style and for better evaluating the geothermal resources that these complexes host. We investigate Aluto, a restless silicic volcano in the MER, and combine a wide range of geochemical and geophysical techniques to constrain magma genesis, storage and eruption processes and shed light on magmatic-hydrothermal-tectonic interactions. Magma genesis and storage processes at Aluto were evaluated using new whole-rock geochemical data from recent eruptive products. Geochemical modelling confirms that Aluto's peralkaline rhyolites, that constitute the bulk of recent erupted products, are generated from protracted fractionation (>80 %) of basalt that is compositionally similar to rift-related basalts found on the margins of the complex. Crustal melting did not play a significant role in rhyolite genesis and melt storage depths of ~5 km can reproduce almost all aspects of their geochemistry. InSAR methods were then used to investigate magma storage and fluid movement at Aluto during an episode of ground deformation that took place between 2008 and 2010. Combining new SAR imagery from different viewing geometries we identified an accelerating uplift pulse and found that source models support depths of magmatic and/or fluid intrusion at ~5 km for the uplift and shallower depths of ~4 km for the subsidence. Finally, gas samples collected on Aluto in 2014 were used to evaluate magma and fluid transport processes. Our results show that gases are predominantly emanating from major fault zones on Aluto and that they

  11. NanoSIMS and Auger Analysis of Impact Craters from the Genesis 'Aluminum Kidney'

    NASA Astrophysics Data System (ADS)

    Floss, C.; Wiesman, H.; Haenecour, P.

    2015-07-01

    Results of NanoSIMS and Auger analyses of two craters from the Genesis polished aluminum collector are reported. Apart from one O-anomalous grain, we found no clear evidence of residue from the impactor particles.

  12. Sample Return Missions Where Contamination Issues are Critical: Genesis Mission Approach

    NASA Technical Reports Server (NTRS)

    Allton, Judith H.; Stansbery E. K.

    2011-01-01

    The Genesis Mission, sought the challenging analytical goals of accurately and precisely measuring the elemental and isotopic composition of the Sun to levels useful for planetary science, requiring sensitivities of ppm to ppt in the outer 100 nm of collector materials. Analytical capabilities were further challenged when the hard landing in 2004 broke open the canister containing the super-clean collectors. Genesis illustrates that returned samples allow flexibility and creativity to recover from setbacks.

  13. GENESIS SciFlo: Enabling Multi-Instrument Atmospheric Science Using Grid Workflows

    NASA Astrophysics Data System (ADS)

    Wilson, B. D.; Tang, B.; Manipon, G.; Yunck, T.; Fetzer, E.; Braverman, A.; Dobinson, E.

    2004-12-01

    The General Earth Science Investigation Suite (GENESIS) project is a NASA-sponsored partnership between the Jet Propulsion Laboratory, academia, and NASA data centers to develop a new suite of web services tools to facilitate multi-sensor investigations in Earth System Science. The goal of GENESIS is to enable large-scale, multi-instrument atmospheric science using combined datasets from the AIRS, MODIS, MISR, and GPS sensors. Investigations will include cross-comparison of spaceborne climate sensors, cloud spectral analysis, study of upper troposphere-strato-sphere water transport, study of the aerosol indirect cloud effect, and global climate model validation. The challenges are to bring together very large datasets, reformat and understand the individual instrument retrievals, co-register or re-grid the retrieved physical parameters, perform computationally-intensive data fusion and data mining operations, and accumulate complex statistics over months to years of data. To meet these challenges, we are developing a Grid computing and dataflow framework, named SciFlo, in which we are deploying a set of versatile and reusable operators for data access, subsetting, registration, mining, fusion, compression, and advanced statistical analysis. SciFlo is a system for Scientific Knowledge Creation on the Grid using a Semantically-Enabled Dataflow Execution Environment. SciFlo leverages Simple Object Access Protocol (SOAP) Web Services and the Grid Computing standards (Globus Alliance toolkits), and enables scientists to do multi-instrument Earth Science by assembling reusable web services and executable operators into a distributed computing flow (operator tree). The SciFlo client & server engines optimize the execution of such distributed data flows and allow the user to transparently find and use datasets and operators without worrying about the actual location of the Grid resources. The scientist injects a distributed computation into the Grid by simply filling out

  14. GENSHELL: A genesis database 2D to 3D shell transformation program

    SciTech Connect

    Sjaardema, G.D.

    1993-07-01

    GENSHELL is a three-dimensional shell mesh generation program. The three-dimensional shell mesh is generated by mapping a two-dimensional quadrilateral mesh into three dimensions according to one of several types of transformations: translation, mapping onto a spherical, ellipsoidal, or cylindrical surface, and mapping onto a user-defined spline surface. The generated three-dimensional mesh can then be reoriented by offsetting, reflecting about an axis, revolving about an axis, and scaling the coordinates. GENSHELL can be used to mesh complex three-dimensional geometries composed of several sections when the sections can be defined in terms of transformations of two-dimensional geometries. The code GJOIN is then used to join the separate sections into a single body. GENSHELL updates the EXODUS quality assurance and information records to help track the codes and files used to generate the mesh. GENSHELL reads and writes two-dimensional and three-dimensional mesh databases in the GENESIS database format; therefore, it is compatible with the preprocessing, postprocessing, and analysis codes in the Sandia National Laboratories Engineering Analysis Code Access System (SEACAS).

  15. Genesis of self-identity as disother: life histories of people who stutter.

    PubMed

    Kathard, Harsha; Pillay, Mershen; Samuel, Michael; Reddy, Vijay

    2004-01-01

    This paper explores the processes shaping self-identity formation as DisOther and the actions of participants who stutter. It illuminates the experiences of adults who stutter using a biographical, narrative, life history methodology. The participants were seven South African adults of diverse racial, social and economic backgrounds from KwaZulu Natal, South Africa. Five males and two females were invited to participate via purposive and convenience sampling processes. Their stories of living with stuttering in their life worlds over time were constructed via biographical interviews using personal, social and temporal lenses typical of life history methodology. The interviews were audio-recorded and transcribed. The data were analysed at two levels using a combination of strategies. The first level entailed a narrative analysis that was represented as research stories for each participant. The cross-case and thematic analysis of research stories constituted the second level analysis of narratives. The findings explain the complex and interrelated personal and social processes over time which contribute to the genesis of self-identity formation as DisOther Social inscriptions of difference occurred in immediate home, school and work contexts over time via multiple processes such as labelling, norming, judging and teasing. Personal processes included discoveries of difference via critical events, repeated reinforcement of difference, self-judgement and temporal burdening. Furthermore, the actions participants took in negotiating stuttering were examined. The implications of the findings and limitations of the study are presented. PMID:16318102

  16. Iron disulfide minerals and the genesis of roll-type uranium deposits.

    USGS Publications Warehouse

    Reynolds, R.L.; Goldhaber, M.B.

    1983-01-01

    Studies of the distribution of and textural relationships among pyrite and marcasite in host rocks for a number of roll-type sedimentary U deposits have enabled identification of several generations of FeS2 minerals. A critical factor influencing mineral formation is the complex relationship of pH and the S species that are precursors of FeS2 minerals. The presence or absence of intrinsic organic matter for bacterial sulphate reduction also plays a key role. In deposits lacking such organic matter, the pre-ore is often euhedral pyrite and the ore-stage is marcasite. In contrast, in deposits containing organic matter the pre-ore is pyrite occurring as framboids or as replacements of plant material, and the ore-stage is also pyrite. These contrasting FeS2 assemblages and their respective modes of origin are consistent with previously proposed biogenic and nonbiogenic theories of the genesis of roll-type U deposits. -J.E.S.

  17. An essay on the nature of hormonal codes involved in the genesis of human neoplasias (review).

    PubMed

    Kodama, M; Kodama, T

    1994-01-01

    We have long been occupied with the motion that the steroid generating system plays a key role as the intermediator between the outer environment and the vulnerable host in the course of carcinogenesis. The purpose of this review article is to rebuild the concept of hormonal carcinogenesis in the light of the developmental flow of endocrinological oncology. Our discussion places much emphasis on the investigation of a number of puzzles surrounding the hormonal signal transmission system in humans as well as in non-human animals. The usefulness of the steroid-responsive enhancer gene/protooncogene complex model was confirmed in the construction of a unifying theory involving chemical carcinogenesis, viral carcinogenesis and hormonal carcinogenesis. We present evidence to suggest that our unifying theory surrounding the hormone-gene relationship is applicable to the genesis of human neoplasia in general, and that members of the human cancer family are interfering with each other in their risk variations in time and space. The nature of steroid substance as the signal transmitter is discussed from the point of view of paleontological endocrinology. PMID:7872697

  18. SARISA: an instrument for analysis of Genesis mission returned samples

    NASA Astrophysics Data System (ADS)

    Veryovkin, I. V.; Calaway, W. F.; Tripa, C. E.; Pellin, M. J.; Burnett, D. S.

    2004-12-01

    To analyze elemental and isotopic composition of solar wind samples returned to Earth by the Genesis spacecraft of NASA's Discovery Program, a special advanced analytical instrument facility was constructed at Argonne National Laboratory. This facility is based on a new time-of-flight mass spectrometer and laser post-ionization of neutral species ion sputtered or laser desorbed from the solar wind collectors. The constructed instrument is called SARISA. It was specifically designed to efficiently use sample during laser post-ionization analysis. Since neutrals are the predominant species in ion sputtering and laser desorption, and laser post-ionization efficiently converts neutrals into ions, this instrument minimizes consumption of sample during analysis so that pieces of the collectors as small as 25 mm2 can be characterized. This is very important for the precious solar wind samples. Also incorporated in the instrument is the capability for ultra-shallow depth profiling analysis with resolution of a few nanometers. This is accomplished by implementing a dual beam technique, which includes low-energy normal-incidence ion bombardment for removing atomic monolayers from the sample surface and micro-focused ion or laser beams for generating secondary neutrals from the exposed surface in order to probe the sample composition. The lateral resolution of the probe beams is 50 nm for ions from a liquid-metal ion source and 0.6 μ m for photons from a desorption laser. Built into SARISA are an in-vacuum all-reflecting optical microscope and a capability of secondary electron imaging using a dedicated detector. The imaging capabilities of SARISA will allow identification of particulate contaminants on the collector surface in order to perform analysis on uncontaminated regions of this surface. Small sample consumption, high analysis resolution and imaging capabilities all are particularly important features of the SARISA instrument because of the condition of the returned

  19. Lessons on tropical cyclone genesis from paleoclimate simulations

    NASA Astrophysics Data System (ADS)

    Korty, R.; Galewsky, J.; Camargo, S. J.

    2011-12-01

    There are many questions about how the climatology of tropical cyclones may change with climate, but the observational record is ill-equipped to address them: it is restricted by a short length, subjective storm intensity estimates, and questions about its completeness. Analysis of 21st century model simulations and theoretical developments have provided some guidance, but it will be many more years before sufficient data exist to finally confirm or refute their predictions of the future. But there is a wealth of data emerging from a variety of paleoclimate approaches, and here we present some avenues for learning from model simulations of the late Pleistocene and Holocene. Atmospheric composition remained fairly steady between the mid-Holocene (6ka) and the preindustrial era, but the latitudinal distribution of incoming solar radiation changed substantially as the perihelion of Earth's orbit progressed from September (6ka) to January (today). The magnitude of the differences at 6ka fades over the late Holocene. We examined the simulations of the paleoclimate intercomparison modeling project (PMIP2) to investigate how the dynamic and thermodynamic factors known to be important for tropical cyclogenesis change in response to cold climates (last glacial maximum) and solar radiation changes (6ka). We find that despite the increase in Northern Hemisphere storm season solar radiation at 6ka, there is a robust decline in the favorability of thermodynamic variables important for genesis (e.g., maximum potential intensity and measures of tropospheric entropy deficits). These changes appear principally related to the differential heating of the ocean surface and free troposphere, but the geographic distribution of changes is not uniform, and model variability is high in the central Pacific. In addition to the genesis factors, we are examining the characteristics of model storm tracks in the latest CESM paleoclimate runs. This high frequency, high resolution output also

  20. Cleaning at the Edge of Science: NASA's Genesis Mission

    NASA Technical Reports Server (NTRS)

    Stansbery, Eileen K.; Biesinger, Paul H.

    2000-01-01

    As part of NASA's continuing exploration of the origins of our solar system, the California Institute of Technology, Jet Propulsion Laboratory, Lockheed Martin Astronautics, Los Alamos National Laboratory, and the Johnson Space Center are working together to develop the Genesis mission to return solar matter for analysis in terrestrial laboratories. These samples will be used to define a baseline for the chemical and isotopic composition of the solar nebula. Deviations from the baseline resulted as the solar system evolved; thus, providing a tracer for materials incorporated into meteorites, comets and planetary bodies. These differences represent "fossil residues" that provide invaluable insight into how the solar nebula evolved to form the planets. We cannot collect a sample of the Sun as we would for a planet; fortunately, solar material comes to us in the form of the solar wind. Ultrapure materials will be exposed at the Earth-Sun L1, outside the Earth's magnetic influence, where solar wind nuclei will be captured for 2 years before returning to Earth in January 2001. The key challenge to obtaining a good sample of solar wind, uncontaminated by terrestrial atoms, is a clean collection surface in a clean sample canister and clean facilities with which to handle the samples for allocation and future reference. The Johnson Space Center QSQ is responsible for contamination control for the mission, for ensuring the cleanliness of collection surfaces and providing a clean environment for their subsequent handling. The level of cleanliness required is high; at the time of analysis (after sample return), the surface contamination by C, N, O must each be less than 10(exp 15) atoms per centimeter squared and for elements other than C, N, O, the number of atoms per centimeter squared of each surface contaminant shall not exceed the estimated solar wind fluence of the species (varies by element between U at approx. 10 (exp 4) atoms per centimeter squared to Fe, Si, Mg, and

  1. Genesis of avian influenza H9N2 in Bangladesh.

    PubMed

    Shanmuganatham, Karthik; Feeroz, Mohammed M; Jones-Engel, Lisa; Walker, David; Alam, SMRabiul; Hasan, MKamrul; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2014-12-01

    Avian influenza subtype H9N2 is endemic in many bird species in Asia and the Middle East and has contributed to the genesis of H5N1, H7N9 and H10N8, which are potential pandemic threats. H9N2 viruses that have spread to Bangladesh have acquired multiple gene segments from highly pathogenic (HP) H7N3 viruses that are presumably in Pakistan and currently cocirculate with HP H5N1. However, the source and geographic origin of these H9N2 viruses are not clear. We characterized the complete genetic sequences of 37 Bangladeshi H9N2 viruses isolated in 2011-2013 and investigated their inter- and intrasubtypic genetic diversities by tracing their genesis in relationship to other H9N2 viruses isolated from neighboring countries. H9N2 viruses in Bangladesh are homogenous with several mammalian host-specific markers and are a new H9N2 sublineage wherein the hemagglutinin (HA) gene is derived from an Iranian H9N2 lineage (Mideast_B Iran), the neuraminidase (NA) and polymerase basic 2 (PB2) genes are from Dubai H9N2 (Mideast_C Dubai), and the non-structural protein (NS), nucleoprotein (NP), matrix protein (MP), polymerase acidic (PA) and polymerase basic 1 (PB1) genes are from HP H7N3 originating from Pakistan. Different H9N2 genotypes that were replaced in 2006 and 2009 by other reassortants have been detected in Bangladesh. Phylogenetic and molecular analyses suggest that the current genotype descended from the prototypical H9N2 lineage (G1), which circulated in poultry in China during the late 1990s and came to Bangladesh via the poultry trade within the Middle East, and that this genotype subsequently reassorted with H7N3 and H9N2 lineages from Pakistan and spread throughout India. Thus, continual surveillance of Bangladeshi HP H5N1, H7N3 and H9N2 is warranted to identify further evolution and adaptation to humans. PMID:26038507

  2. Genesis of avian influenza H9N2 in Bangladesh

    PubMed Central

    Shanmuganatham, Karthik; Feeroz, Mohammed M; Jones-Engel, Lisa; Walker, David; Alam, SMRabiul; Hasan, MKamrul; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2014-01-01

    Avian influenza subtype H9N2 is endemic in many bird species in Asia and the Middle East and has contributed to the genesis of H5N1, H7N9 and H10N8, which are potential pandemic threats. H9N2 viruses that have spread to Bangladesh have acquired multiple gene segments from highly pathogenic (HP) H7N3 viruses that are presumably in Pakistan and currently cocirculate with HP H5N1. However, the source and geographic origin of these H9N2 viruses are not clear. We characterized the complete genetic sequences of 37 Bangladeshi H9N2 viruses isolated in 2011–2013 and investigated their inter- and intrasubtypic genetic diversities by tracing their genesis in relationship to other H9N2 viruses isolated from neighboring countries. H9N2 viruses in Bangladesh are homogenous with several mammalian host-specific markers and are a new H9N2 sublineage wherein the hemagglutinin (HA) gene is derived from an Iranian H9N2 lineage (Mideast_B Iran), the neuraminidase (NA) and polymerase basic 2 (PB2) genes are from Dubai H9N2 (Mideast_C Dubai), and the non-structural protein (NS), nucleoprotein (NP), matrix protein (MP), polymerase acidic (PA) and polymerase basic 1 (PB1) genes are from HP H7N3 originating from Pakistan. Different H9N2 genotypes that were replaced in 2006 and 2009 by other reassortants have been detected in Bangladesh. Phylogenetic and molecular analyses suggest that the current genotype descended from the prototypical H9N2 lineage (G1), which circulated in poultry in China during the late 1990s and came to Bangladesh via the poultry trade within the Middle East, and that this genotype subsequently reassorted with H7N3 and H9N2 lineages from Pakistan and spread throughout India. Thus, continual surveillance of Bangladeshi HP H5N1, H7N3 and H9N2 is warranted to identify further evolution and adaptation to humans. PMID:26038507

  3. Genesis of oil and hydrocarbon gases within Mars and carbonaceous chondrites from our solar system: organic origin (source rocks or direct biogenic sink?)

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Prasanta K.

    2011-10-01

    The petroleum hydrocarbons (oil and gas) and kerogen macromolecules are abundant within the extraterrestrial atmospheric particles. These hydrocarbons occur as reservoir of lakes and oceans or in hydrate forms on various planets (Earth, Mars, moons of Saturn and Jupiter), asteroid belts, carbonaceous chondrites, and as solid residue within the planets or moons in the Solar System and beyond. The abundance of PAHs in the outer Solar System may indicate that the genesis of these primitive biomarker hydrocarbons may have formed abiogenically much earlier (> 5Ga) than the formation of our Solar System (~ 5 Ga). However, the origin of petroleum on Earth is overwhelmingly connected to the biogenic organic matter that is related to source rocks (thermal degradation of macromolecular kerogen). This may show a similar genesis of the kerogen macromolecules and petroleum hydrocarbons (oil and gas) within the carbonaceous chondrites (CCs), Mars, and selected moons from Saturn and Jupiter. They may be biologically and genetically related. Recent evidence of the possible presence of source rocks (organic rich black carbonaceous rocks) and associated petroleum system elements within Eberswalde and Holden areas of Mars may indicate similar terrestrial associations. Similarly, studies of Carbonaceous Chondrites using biological, petrological, SEM/EDS, and petroleum geochemical methods may also indicate the presence of source rock macromolecule within the CCs. These studies pointed out two new issues: (1) approximately, the major part of the CCs possibly originated from archaea, bacteria, and primitive algal remains; and (2) three types of temperature events affecting the petroleum generation within these carbonaceous chondrites: (i) lower temperature events (<200oC) in comets and cooler asteroids or planets (examples: Murchison, Tagish Lake, Orgueil); (ii) intermediate temperature events (200 - 300oC) as associated within the deeper section of the comets, asteroids or planets

  4. Integration of Petrologic, Geophysical, and Gas Monitoring Data at Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Thornber, C. R.; Lee, R. L.; Gansecki, C. A.; Orr, T. R.; Miklius, A.; Sutton, A. J.; Thelen, W. A.

    2014-12-01

    Well-quenched, near-vent lava samples taken at weekly to monthly intervals during the past 31 years of near-continuous Kilauea East Rift Zone (ERZ) eruption have yielded an unprecedented temporal record of petrology and geochemistry. Salient petrologic parameters derived from bulk lava major- and trace-element geochemistry, and from microprobe analyses of matrix glasses, phenocrysts, and melt-inclusions, are now incorporated into the USGS Volcano Science Center's near real-time volcano-monitoring software platform, called the Volcano Analysis and Visualization Environment (VALVE). The petrologic parameters now imported into VALVE for correlation with geophysical and gas data streams are: 1) MgO systematics of bulk lava, glass, and olivine, used to portray pre-eruptive magma temperature and temperature of lava erupted at the vent, 2) incompatible element ratios of bulk lava and glass, used to track either sudden or long-term magma-mixing or magma-source changes , and 3) magmatic sulfur, measured within glass inclusions of olivine, used to infer pre-eruptive volatile content of magma. Petrologic data in VALVE provides added insight into magmatic processes. For example, since the onset of Kilauea's summit eruption in 2008, correlations of summit deformation with MgO systematics and magmatic sulfur in coeval summit tephra and ERZ lava, along with their identical incompatible-element signatures, demonstrate summit-to-ERZ magmatic continuity. As constrained by geophysical and geologic observations at both ends of the eruptive plumbing system, changes in petrology of lava erupted at Puu Oo are likely associated with physical maturation of magma pathways along the shallow ERZ conduit, repeated intrusions and systematic over-pressurization during the 2003-2007 surge in magma supply. Two fissure eruptions uprift of Puu Oo in January 1997 and March 2011 also show a strong correlation of geophysical and gas signatures with a petrologic shift to cooler, incompatible

  5. Ore petrology of chromite-PGE mineralization in the Kempirsai ophiolite complex

    NASA Astrophysics Data System (ADS)

    Distler, V. V.; Kryachko, V. V.; Yudovskaya, M. A.

    2008-01-01

    The platinum group minerals (PGM) in chromite ores of the Kempirsai ophiolite massif, located south of the Ural Mountains, are extremely varied in composition and represented predominantly by alloys, sulfides, arsenides, and sulfosalts of the iridium-group PGE (IPGE). The earlier Ir-Os-Ru alloys prevail over the later Cu-Os-Ru, Cu-Ir, Ni-Ir, Ni-Os-Ir-Ru, and Ni-Ru-Os-Fe alloys rich in base metals (BM). The earlier Ru-Os disulfides crystallize coevally with Ir-Os-Ru alloys, whereas the later sulfides are represented by compounds with a variable stoichiometry and a wide miscibility of Ni, Cu, Ir, Rh, Os, and Fe. Phase relations of PGE alloys with PGE-BM alloys, sulfides and sulfoarsenides confirm that deposition of these minerals was defined by a general evolution of PGE fractionation in the mineral-forming system but not by a super-imposed process. The leading mechanism of PGM crystallization is thought to be their dendritic growth during gas-transport reactions from low-density gaseous fluid enriched in PGE. The representative technological sampling of 0.5 million tons of an ore showed that the average PGE content in chromite ore is 0.71 ppm which leads to an evaluation of the PGE resources to be no less than 250 tons. Hence, the Kempirsai deposit is not only a giant chromium deposit, but also a giant deposit of IPGE: Ir, Ru, and Os. The size parameters of PGM and their aggregates suggests that the PGE may be recoverable in separate concentrates.

  6. Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution

    NASA Astrophysics Data System (ADS)

    Bogard, Donald D.; Garrison, Daniel H.; McCoy, Timothy J.

    2000-06-01

    IIE iron meteorites contain silicate inclusions the characteristics of which suggest a parent body similar to that of H-chondrites. However, these silicates show a wide range of alteration, ranging from Netschaëvo and Techado, the inclusions of which are little altered, to highly differentiated silicates like those in Kodaikanal, Weekeroo Station, and Colomera, which have lost metal and sulfur and are enriched in feldspar. We find these inclusions to show varying degrees of shock alteration. We made 39Ar- 40Ar age determinations of Watson, Techado, Miles, Colomera, and Sombrerete. Watson has an Ar-Ar age of 3.677 ± 0.007 Gyr, similar to previously reported ages for Kodaikanal and Netschaëvo. We suggest that the various determined radiometric ages of these three meteorites were probably reset by a common impact event. The space exposure ages for these three meteorites are also similar to each other and are considerably younger than exposure ages of other IIEs. 39Ar- 40Ar ages inferred for the other four meteorites analyzed are considerably older than Watson and are: Techado = 4.49 ± 0.01 Gyr, Miles = 4.405 ± 0.012 Gyr, Colomera = 4.470 ± 0.010 Gyr, and Sombrerete = 4.541 ± 0.0012 Gyr. These ages are in fair agreement with previously reported Rb-Sr isochron ages for Colomera and Weekeroo Station. Although several mechanisms to form IIE meteorites have been suggested, it is not obvious that a single mechanism could produce a suite of meteorites with very different degrees of silicate differentiation and with isotopic ages that differ by >0.8 Gyr. We suggest that those IIEs with older isotopic ages are a product of partial melting and differentiation within the parent body, followed by mixing of silicate and metal while both were relatively hot. Netschaëvo and Watson may have formed by this same process or by impact mixing ˜4.5 Gyr ago, but their isotopic ages may have been subsequently reset by shock heating. Kodaikanal apparently is required to have formed more recently, in which case impact melting and differentiation seems the only viable process. We see no compelling reasons to believe that IIE silicate and metal derived from different parent bodies or that the parent body of IIEs was the same as that of H-chondrites.

  7. Chronology and Petrology of Silicates From IIE Iron Meteorites: Evidence of a Complex Parent Body Evolution

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Garrison, Daniel H.; McCoy, Timothy J.

    1999-01-01

    IIE iron meteorites contain silicate inclusions whose characteristics suggest a parent body similar to that of H-chondrites. However, these silicates show a wide range of alteration, ranging from Netschadvo and Techado, whose inclusions are little altered. to highly differentiated silicates like-those in Kodaikanal, Weekeroo Station and Colomera, which have lost metal and sulfur and are enriched in feldspar. We find these inclusions to show varying degrees of shock alteration. Because only a limited amount of data on - isotopic ages of HE silicates were available, we made Ar-39 - Ar-40 age determinations of Watson, Techado, miles Colomera, and Sombrerete. Watson has an Ar-Ar age of 3.653 +/- 0.012 Gyr, similar to previously reported ages for Kodaikanal and Netschadvo. We suggest that the various determined radiometric ages of these three meteorites were probably reset by a common impact event. The space exposure ages for these three meteorites are also similar to each other and are considerably younger than exposure ages of other IIEs. Ar-39 - Ar-40 ages inferred for the other four meteorites analyzed are considerably older than Watson and are: Techado =4.49 +/- 0.01 Gyr, Miles =4.412 +/- 0.016 Gyr, Colomera =4.469 +/- 0.012 Gyr, and Sombrerete =4.535 +/- 0.005 Gyr. These ages are in fair agreement with previously reported Rb-Sr isochron ages for Colomera and Weekeroo Station. Although several mechanisms to form HE meteorites previously were suggested, it is not obvious that a single mechanism could produce a suite of meteorites with very different degrees of silicate differentiation and with isotopic ages that differ by >0.8 Gyr. We suggest that those IIEs with older isotopic ages are a product of partial melting and differentiation within the parent body, followed by mixing of silicate and metal while both were relatively hot. Netschadvo and Watson may have formed by this same process or by impact mixing about 4.5 Gyr ago, but their isotopic ages were subsequently reset by shock heating. Kodaikanal apparently is required to have formed more recently, in which case impact melting and differentiation seems the only viable process. We see no compelling reasons to believe that IIE silicate and metal derived from different parent bodies or that the parent body of IIEs was the same as that of H-chondrites.

  8. Lithospheric structure of the Iberian Peninsula from coupled geophysical-petrological inversion

    NASA Astrophysics Data System (ADS)

    Fullea, Javier; Negredo, Ana; Charco, Maria; Palomeras, Inmaculada; Villaseñor, Antonio; Afonso, Juan Carlos

    2016-04-01

    The objective of this study is to obtain robust and high-resolution estimations of the thermal, compositional and density structure of the lithospheric/sublithospheric upper mantle system beneath the Iberian Peninsula. Such a high-resolution model will provide a reliable picture of the present day lithospheric structure, a crucial constraint to understand the complex geodynamic evolution in the study area. As a first step towards a full 3D inversion, we have performed a 1D nonlinear Bayesian (probabilistic) inversion of a wide variety of data sets (surface wave dispersion curves, surface heat flow, elevation), extensively exploring the parameter space by means of a coupled geophysical-petrological inversion algorithm. The most prominent feature in the modeled structure is the progressive northward and northeastward steepening of the lithospheric-asthenospheric boundary (LAB) below the Ebro basin, reaching > 120 km under the central and western Pyrenees. Similarly, absolute maximum values of crustal thickness are obtained in the central Pyrenees, locally exceeding 45 km. Further to the west the Moho discontinuity shallows to about 35 km beneath the Cantabrian Cordillera. A dramatic decrease in both crustal and lithospheric thickness is observed from the central towards the easternmost Pyrenees, reaching depths of about 25 km and 90 km for the Moho and LAB respectively. Average Moho depth values of about 30 km are estimated in the central Iberian Peninsula. A slightly thicker crust is predicted under the Gibraltar arc than under the Betics, consistently with the deeper LAB beneath the former, most likely reflecting the presence of a sinking lithospheric slab. For the rest of the Iberian Peninsula a rather flat topography of LAB and Moho is observed, with moderate lithospheric thinning below the central western and SE Iberian margins. Isostatic topography related to variations in predicted crustal thickness shows significant discrepancies form observed topography

  9. Petrology and Geochemistry of the Eocene Volcanic Rocks in the Kahrizak Mountains, Central Iran

    NASA Astrophysics Data System (ADS)

    Yazdani, S.; Castillo, P.; Tutti, F.

    2013-12-01

    The Eocene volcanic rocks in the Kahrizak (KH) Mountains in the northern part of Central Iran were mainly formed by magmatism that accompanied block-faulting tectonism in the region. In the KH area, the volcanic rocks are nonconformably overlain by Oligocene-Pliocene sedimentary deposits, suggesting that the Eocene magmatic activity in the region was followed by a sequence of uplift and shallow marine regression. The volcanic rocks consist of pyroclastics (tuff and ignimbrites) and lava flows (basalt, basaltic trachyandesite, trachyandesite, and rhyolite); superposition indicates an earlier explosive volcanic phase that caused the widespread distribution of rhyolitic ignimbrites and tuffs, and this was followed by a quieter phase of lava eruptions. Petrographic evidence such as mineral zoning, sieve texture and rounded crystals of plagioclase and pyroxene phenocrysts indicate non-equilibrium conditions between melt and crystals during magma cooling. These textures suggest magma mixing, although these may also be due to rapid decompression, where heat loss is minor relative to the ascent rate. The geochemistry of KH samples indicates their subalkaline to alkaline affinity. In terms of trace element contents, most samples exhibit the distinct geochemical trait of arc volcanism, i.e., Nb and Ta depletions relative to LILE (e.g., Ba, Rb) enrichment and positive Sr anomaly; however, Zr and Ti depletions are not prominent. The samples have a light-REE enriched but flat heavy-REE pattern and negative Eu anomaly in the rhyolites and trachyandesites. They have a ~narrow to ~moderate range of Pb isotopic ratios (206Pb/204Pb ~18.6-18.9, 207Pb/204Pb ~15.5-15.6, and 208Pb/204Pb ~38.5-38.8), with basaltic rocks somewhat higher than rhyolitic rocks. Available geochemical and isotopic data suggest a complex origin and evolution of the KH magmas. The magmas originated from an intrinsically ~heterogeneous source and, in addition to fractional crystallization, some of the

  10. 3D Integrated geophysical-petrological modelling of the Iranian lithosphere

    NASA Astrophysics Data System (ADS)

    Mousavi, Naeim; Ardestani, Vahid E.; Ebbing, Jörg; Fullea, Javier

    2016-04-01

    The present-day Iranian Plateau is the result of complex tectonic processes associated with the Arabia-Eurasia Plate convergence at a lithospheric scale. In spite of previous mostly 2D geophysical studies, fundamental questions regarding the deep lithospheric and sub-lithospheric structure beneath Iran remain open. A robust 3D model of the thermochemical lithospheric structure in Iran is an important step toward a better understanding of the geological history and tectonic events in the area. Here, we apply a combined geophysical-petrological methodology (LitMod3D) to investigate the present-day thermal and compositional structure in the crust and upper mantle beneath the Arabia-Eurasia collision zone using a comprehensive variety of constraining data: elevation, surface heat flow, gravity potential fields, satellite gravity gradients, xenoliths and seismic tomography. Different mantle compositions were tested in our model based on local xenolith samples and global data base averages for different tectonothermal ages. A uniform mantle composition fails to explain the observed gravity field, gravity gradients and surface topography. A tectonically regionalized lithospheric mantle compositional model is able to explain all data sets including seismic tomography models. Our preliminary thermochemical lithospheric study constrains the depth to Moho discontinuity and intra crustal geometries including depth to sediments. We also determine the depth to Curie isotherm which is known as the base of magnetized crustal/uppermost mantle bodies. Discrepancies with respect to previous studies include mantle composition and the geometry of Moho and Lithosphere-Asthenosphere Boundary (LAB). Synthetic seismic Vs and Vp velocities match existing seismic tomography models in the area. In this study, depleted mantle compositions are modelled beneath cold and thick lithosphere in Arabian and Turan platforms. A more fertile mantle composition is found in collision zones. Based on our 3

  11. Petrology of the most recent ultrapotassic magmas from the Roman Province (Central Italy)

    NASA Astrophysics Data System (ADS)

    Gaeta, M.; Freda, C.; Marra, F.; Di Rocco, T.; Gozzi, F.; Arienzo, I.; Giaccio, B.; Scarlato, P.

    2011-11-01

    We report on the newly discovered lava flow that erupted in the Colli Albani Volcanic District, which is the most recent and, geochemically the most peculiar effusive event recognised in the entire ultrapotassic Roman Province (Central Italy). This lava flow is associated with the Monte Due Torri scoria cone, located approximately 5 km south of the Albano hydromagmatic centre (69-36 ka). The Monte Due Torri scoria cone displays well-preserved morphological characteristics and the 40 ± 7 ka age determined for the associated lava flow indicates that its activity was nearly contemporaneous to the most recent, explosive activity that occurred at the Albano centre from 41 to 36 ka. By comparing chemical and petrological features of the Monte Due Torri lava flow, Albano products, and older products (> 69 ka), we show that the youngest Colli Albani eruptions were fed by two new batches of parental magmas that originated in a phlogopite-bearing metasomatised mantle, each one feeding one of the two youngest eruptive cycles (at 69 ka and 41-36 ka). The trace element signature, e.g., very low Pb content, of primitive (MgO > 3 wt.%) magmas feeding the initiation of the hydromagmatic activity at Albano (69 ka) and the subsequent effusive activity at Monte Due Torri (40 ka) indicates that a magma chamber located in the deep anhydrite-bearing dolomite formation was tapped. However, the polygenic activity, the changes in magma composition, and the variable thermometamorphic clasts occurring in the hydromagmatic deposits (recording variable substrata) suggest, particularly for the Albano eruptive centre, a more complex plumbing system consisting of at least two more magma chambers at a shallower depth, i.e., in the Mesozoic limestone and Pliocene pelite formations. The large amount of stratigraphic, volcanological, and geochemical data collected for the Colli Albani Volcanic District, one of the main districts in the ultrapotassic Roman Province, enable us to contribute insights

  12. Petrology and geochemistry of the San Félix-San Ambrosio islands, Eastern Pacific

    NASA Astrophysics Data System (ADS)

    Cooper Percker, Oliver; Lara, Luis E.

    2015-04-01

    The San Félix-San Ambrosio (SF-SA) islands, Eastern Pacific, are fragments of two volcanic sequences 20 km apart. Both represent the top of an eroded large shield-volcano which rises over the Nazca Plate. Here, new geochemical and 40Ar/39Ar geochronological data are presented in order to understand magmatic evolution and source features. Two units are recognized on the SF island: (1) the Cerro Amarillo unit (CAU) (190±30 ka) formed by a hyaloclastic-tuff cone and basanitic lavas (Ba/Yb=519; Ba/Zr=2.19; La/Yb=49.88; Nb/Ta=17.96; Nb/Y=3.78; Nb/Zr=0.25) with absent or scarce modal content of plagioclase (<5%); and (2) Plateau unit (PU) (210±60 ka) formed by a basanitic lava succession with high modal content of plagioclase (>20%). The hyaloclastic-tuff cone of the CAU contains aphanitic-trachytic lithic fragments of Na-augite and kaersutite, which correspond to the final product of fractional crystallization of olivine+clinopyroxene+Fe-Ti oxides+apatite±plagioclase from alkaline primitive liquids similar to SF-SA lavas. The geochemical data suggest that the islands represent different evolutive stages of a same volcanic intraplate complex. The alkaline to transitional SA lavas (Ba/Yb=249; Ba/Zr=1.60; La/Yb=24.62; Nb/Ta=16.55; Nb/Y=2.22; Nb/Zr=0.19) would represent the shield stage (ca 2.9 Ma), while the basanitic SF lavas the post-erosional stage (ca 0.2 Ma). Considering the Sr-Nd-Pb isotopic data of the SF-SA lavas, previous works have ruled out a genetic relationship between SF-SA islands and the nearby Nazca Ridge. An heterogeneous mantle plume with mantelic metasomatized recycled lithologies is hypothesized as a possible magmatic source capable of explaining the petrologic differences between the SF-SA islands and between the CAU and PU, in SF island. This research is supported by FONDECYT Project 1141303.

  13. Baryon and dark matter genesis from strongly coupled strings

    NASA Astrophysics Data System (ADS)

    Heckman, Jonathan J.; Rey, Soo-Jong

    2011-06-01

    D3-brane probes of E-type Yukawa points lead to strongly coupled nearly conformal sectors nearby the Standard Model (visible sector) which are motivated by F-theory GUTs. Realistic visible sector brane configurations induce a seesaw mass hierarchy in the hidden sector with light GUT singlets charged under a strongly coupled hidden sector U(1). Interpreting these GUT singlets as dark matter, this leads to a matter genesis scenario where the freeze out and subsequent decay of heavy mediators between the two sectors simultaneously populates comparable amounts of baryon and dark matter asymmetry. Generating a net matter asymmetry requires a generational structure in the probe sector which is absent at weak string coupling, but is automatically realized at strong string coupling via towers of dyonic bound states corresponding to multi-prong string junctions. The hidden U(1) couples to the visible sector through both electric and magnetic kinetic mixing terms, providing an efficient means to deplete the symmetric component of dark matter. The mass of the dark matter is of order ˜ 10 GeV. The dark matter mass and the matter asymmetry are both controlled by the scale of conformal symmetry breaking ˜ 109 - 1013 GeV, with the precise relation between the two set by details of the visible sector brane configuration.

  14. The Big Bang, Genesis, and Knocking on Heaven's Door

    NASA Astrophysics Data System (ADS)

    Gentry, Robert

    2012-03-01

    Michael Shermer recently upped the ante in the big bang-Genesis controversy by citing Lisa Randall's provocative claim (Science 334, 762 (2011)) that ``it is inconceivable that God could continue to intervene without introducing a material trace of his actions.'' So does Randall's and Shermer's agreement that no such evidence exists disprove God's existence? Not in my view because my 1970s Science, Nature and ARNS publications, and my article in the 1982 AAAS Western Division's Symposium Proceedings, Evolution Confronts Creation, all contain validation of God's existence via discovery of His Fingerprints of Creation and falsification of the big bang and geological evolution. These results came to wide public/scientific attention in my testimony at the 1981 Arkansas creation/evolution trial. There ACLU witness G Brent Dalrymple from the USGS -- and 2005 Medal of Science recipient from President Bush -- admitted I had discovered a tiny mystery (primordial polonium radiohalos) in granite rocks that indicated their almost instant creation. As a follow-up in 1992 and 1995 he sent out SOS letters to the entire AGU membership that the polonium halo evidence for fiat creation still existed and that someone needed to urgently find a naturalistic explanation for them. Is the physics community guilty of a Watergate-type cover-up of this discovery of God's existence and falsification of the big bang? For the answer see www.halos.tv.

  15. Climatology and Genesis Environment of North Atlantic Polar Lows

    NASA Astrophysics Data System (ADS)

    Michel, Clio; Spengler, Thomas

    2016-04-01

    Polar lows are intense maritime cyclones occurring during cold air outbreaks in high latitudes. We use the Melbourne University cyclone algorithm to detect and track polar lows. The algorithm employs the Laplacian of mean sea level pressure and is applied to the ERA-Interim reanalyses from 1979 to 2014. Track density maps indicate that polar lows mainly occur close to Svalbard, as well as in the northern Norwegian Sea and the Barents Sea. This is in accordance to previous studies about polar low tracks densities which are using less objective method and shorter time periods. Also the cyclogenesis density correlates well with the winter-time climatology of cold air outbreaks. Furthermore, we present inter- and intra-annual variability of polar lows and its relation to the NAO as well as sea ice extent. We also differentiated the polar low genesis environment into forward and reverse shear conditions, where forward shear implies that the thermal and mean wind are in the same direction, whereas they are opposite for reverse shear conditions. The forward and reverse shear results based on the objective tracking are similar to a previous study based on polar low tracks from the STARS data set provided by MET Norway.

  16. Flare Genesis Experiment: magnetic topology of Ellerman bombs

    NASA Astrophysics Data System (ADS)

    Schmieder, B.; Pariat, E.; Aulanier, G.; Georgoulis, M. K.; Rust, D. M.; Bernasconi, P. N.

    2002-12-01

    Flare Genesis Experiment (FGE), a balloon borne Observatory was launched in Antarctica on January 10, 2000 and flew during 17 days. FGE consists of an 80 cm Cassegrain telescope with an F/1.5 ultra-low-expansion glass primary mirror and a crystalline silicon secondary mirror. A helium-filled balloon carried the FGE to an altitude of 37 km (Bernasconi et al. 2000, 2001). We select among all the observations a set of high spatial and temporal resolution observations of an emerging active region with numerous Ellerman bombs (EBs). Statistical and morphology analysis have been performed. We demonstrate that Ellerman bombs are the result of magnetic reconnection in the low chromosphere by a magnetic topology analysis. The loci of EBs coincide with "bald patches" (BPs). BPs are regions where the vector field is tangential to the boundary (photosphere) along an inversion line. We conclude that emerging flux through the photosphere is achieved through resistive emergence of U loops connecting small Ω loops before rising in the chromosphere and forming Arch Filament System (AFS).

  17. Genesis of elevated aerosol loading over the Indian region

    NASA Astrophysics Data System (ADS)

    Prijith, S. S.; Rao, P. V. N.; Mohan, Mannil

    2016-05-01

    Elevated aerosols assume importance as the diabatic heating due to aerosol absorption is more intense at higher altitudes where the atmosphere becomes thinner. Indian region, especially its central and northern latitudes, experiences significant loading of elevated aerosols during pre-monsoon and summer months. Genesis of elevated aerosol loading over Indian region is investigated in the present study, using multi-year satellite observations from Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and Moderate Resolution Imaging Spectroradiometer (MODIS) along with reanalysis winds from MERRA. Central India is observed to have prominent aerosols loading at higher altitudes during pre-monsoon season, whereas it is during summer months over north-west India. Further analysis reveals that the elevated aerosols over Indian region in pre-monsoon and summer months are significantly contributed by transported mineral dust from the arid continental regions at west. In addition to the mineral dust advection, aerosols at higher altitudes over Indian region are enriched by strong convection and associated vertical transport of surface level aerosols. Vertical transport of aerosols observed over Indian region during pre-monsoon and summer months is aided by intense convergence at the surface level and divergence at the upper level. Moreover, aerosol source/sink strength estimated using aerosol flux continuity equation show significant aerosol production over central India during pre-monsoon. Strong vertical transport prevails during pre-monsoon uplifts the locally produced aerosols, with considerable anthropogenic fraction, to higher altitudes where their impacts would be more intense.

  18. Aerothermodynamic Environment Definition for the Genesis Sample Return Capsule

    NASA Technical Reports Server (NTRS)

    Cheatwood, F. McNeil; Merski, N. Ronald, Jr.; Riley, Christopher J.; Mitcheltree, Robert A.

    2001-01-01

    NASA's Genesis sample return mission will be the first to return material from beyond the Earth-Moon system. NASA Langley Research Center supported this mission with aerothermodynamic analyses of the sample return capsule. This paper provides an overview of that effort. The capsule is attached through its forebody to the spacecraft bus. When the attachment is severed prior to Earth entry, forebody cavities remain. The presence of these cavities could dramatically increase the heating environment in their vicinity and downstream. A combination of computational fluid dynamics calculations and wind tunnel phosphor thermography tests were employed to address this issue. These results quantify the heating environment in and around the cavities, and were a factor in the decision to switch forebody heat shield materials. A transition map is developed which predicts that the flow aft of the penetrations will still be laminar at the peak heating point of the trajectory. As the vehicle continues along the trajectory to the peak dynamic pressure point, fully turbulent flow aft of the penetrations could occur. The integrated heat load calculations show that a heat shield sized to the stagnation point levels will be adequate for the predicted environment aft of the penetrations.

  19. On the genesis of the idiotypic network theory.

    PubMed

    Civello, Andrea

    2013-01-01

    The idiotypic network theory (INT) was conceived by the Danish immunologist Niels Kaj Jerne in 1973/1974. It proposes an overall view of the immune system as a network of lymphocytes and antibodies. The paper tries to offer a reconstruction of the genesis of the theory, now generally discarded and of mostly historical interest, first of all, by taking into account the context in which Jerne's theoretical proposal was advanced. It is argued the theory challenged, in a sense, the supremacy of the clonal selection theory (CST), this being regarded as the predominant paradigm in the immunological scenario. As CST found shortcomings in explaining certain phenomena, anomalies, one could view INT as a competing paradigm claiming to be able to make sense of such phenomena in its own conceptual framework. After a summary outline of the historical background and some relevant terminological elucidations, a narrative of the various phases of elaboration of the theory is proposed, up to its official public presentation. PMID:23207664

  20. Research on genesis of adipocytic metaplasia in uterine fibroids.

    PubMed

    Sośnik, Henryk; Jeleń, Michał; Kosiński, Mariusz; Sośnik, Katarzyna

    2015-12-01

    The genesis of lipoleiomyoma has not been explained yet. Immunohistochemical examinations were performed on 17 lipoleiomyomas in women aged 43-82 (mean age: 51 ±9 years). Four types of myomas were distinguished: 1) pure leiomyoma, 2) fibroleiomyoma, 3) hyalinizing leiomyoma, 4) strongly hyalinized myoma, along with three degrees of progression of adipocytic metaplasia: 1) up to 25% of lipocytes, 2) up to 50% of lipocytes, and 3) over 50% of lipocytes in the analyzed sample, along with three degrees of progression of adipocytic metaplasia: 1) up to 25% of lipocytes, 2) up to 50% of lipocytes, and 3) over 50% of lipocytes in the analyzed sample. A positive correlation was found between the age of women and rate of development of metaplasia (r = 0.51, p = 0.035) as well as with activity of the estrogen receptor in the primary tumor (r = 0.53, p = 0.03). New mucous perivascular tissue was reported among 11.8% of patients and on this basis lipocytes were formed. The appearance of subendothelial granular cells of large blood vessels with a positive reaction for smooth muscle actin (SMA) and CD68 was reported in 17.7%. Results of immunohistochemical research seem to confirm that lipocytes de novo come from the primal pluripotent cells of the tumor stroma and not from the fatty degeneration of myocytes. PMID:27003773

  1. Deciphering the Minimal Algorithm for Development and Information-genesis

    NASA Astrophysics Data System (ADS)

    Li, Zhiyuan; Tang, Chao; Li, Hao

    During development, cells with identical genomes acquires different fates in a highly organized manner. In order to decipher the principles underlining development, we used C.elegans as the model organism. Based on a large set of microscopy imaging, we first constructed a ``standard worm'' in silico: from the single zygotic cell to about 500 cell stage, the lineage, position, cell-cell contact and gene expression dynamics are quantified for each cell in order to investigate principles underlining these intensive data. Next, we reverse-engineered the possible gene-gene/cell-cell interaction rules that are capable of running a dynamic model recapitulating the early fate decisions during C.elegans development. we further formulized the C.elegans embryogenesis in the language of information genesis. Analysis towards data and model uncovered the global landscape of development in the cell fate space, suggested possible gene regulatory architectures and cell signaling processes, revealed diversity and robustness as the essential trade-offs in development, and demonstrated general strategies in building multicellular organisms.

  2. Evolution of Pleistocene to Holocene eruptions in the Lesser Caucasus Mts:Insights from geology, petrology, geochemistry and geochronology

    NASA Astrophysics Data System (ADS)

    Savov, Ivan; Meliksetian, Khachatur; Connor, Charles; Karakhanian, Arkadi; Sugden, Patrick; Navasardyan, Gevorg; Halama, Ralf; Ishizuka, Osamu; Connor, Laura; Karapetian, Sergei

    2016-04-01

    Both effusive and highly explosive (VEI>5) and often voluminous caldera volcanism has developed atop the collision zone between the Arabian and the Eurasian plates. Currently what is exposed on the Anatolian-Armenian-Iranian active orogenic plateau is post-Mesozoic felsic to intermediate collision-related plutons, and mostly collision or post-collision related Quaternary volcanic structures. We have studied in detail the volcanism, tectonics and geophysics on the territory of E.Turkey and Armenia, where several large stratovolcanoes (Ararat, Lesser Ararat, Aragats, Tsghuk, Ishkhanasar) are surrounded by distinct monogenetic volcanic fields (distributed volcanism). These large in volume stratovolcanoes and the associated low volume monogenetic cones range from normal calk-alkaline to high-K shoshonitic in affinity, with their products ranging from basanites to high K trachytes and rhyolites. Several volcanic provinces, namely Kechut/Javakheti, Aragats, Gegham, Vardenis and Syunik are recognized in Armenia and each of them has > 100 mapped volcanoes. These have distinct geochemical (mineral chemistry, trace element and Sr-Nd-B isotope systematics) and petrological (melt eruption temperatures and volatile contents) fingerprints that may or may not vary over time. Age determinations and volcano-stratigraphy sections for each of the case studies we aim to present shows that the volcanism includes a continuous record from Pleistocene to Holocene, or even historical eruptions. The excellent volcano exposures and the now complete high resolution database (GIS), geological mapping, and new and improved K-Ar and Ar-Ar geochronology, uniquely allows us to evaluate the driving forces behind the volcanism in this continent-continent collision setting that is uniquely associated with long lasting eruption episodes. We shall compare the now well studied historical/Holocene eruptions with those pre-dating them, with the aim to identify possible geochemical or petrological

  3. XANES spectroscopy as a tool to trace phosphorus transformation during soil genesis and mountain ecosystem development from lake sediments

    NASA Astrophysics Data System (ADS)

    Giguet-Covex, C.; Poulenard, J.; Chalmin, E.; Arnaud, F.; Rivard, C.; Jenny, J.-P.; Dorioz, J.-M.

    2013-10-01

    The aim of this study is to investigate phosphorus (P) species modifications triggered by soil genesis and mountain ecosystem development after glacial retreat using a lake sediment archive (Lake Anterne, North French Alps). Five lake sediment samples, representative of different stages of soil and ecosystem development, were selected for P speciation analyses. Furthermore, a sequence of current soils from the catchment was analyzed to better constrain our interpretations of the lacustrine archive. Synchrotron techniques (X-ray Fluorescence (XRF) mapping and P K-edge X-ray absorption near edge structure (XANES) spectroscopy) were applied to lake sediments, soils, and standards (mineral and organic) to distinguish between different P species. The results show that soil development during the first millennia of the Holocene triggered increased P species diversity. At the onset of the Holocene, P was present as apatite when rocks and leptosols dominated the catchment. Pedogenic processes then led to apatite dissolution and the formation of large amounts of P on metal/clay-organic complexes. P geochemistry during the main step of soil genesis (early leptosols dominated by apatite, low weathered cambisols with P mainly adsorbed on iron oxides, highly weathered podzols with large amounts of P on Al/Fe/clay organic complexes) is thus clearly recorded in lake sediments. P K-edge XANES spectroscopy is particularly relevant as qualitative method to study P species in soils and lake sediments at high spatial resolution. Such resolution is needed to reveal the diversity of small P particles and like this better characterize the P cycle and improve our understanding of ecosystem evolution.

  4. Petrologic and mineralogic investigation of some crystalline rocks returned by the Apollo 14 mission.

    NASA Technical Reports Server (NTRS)

    Gancarz, A. J.; Albee, A. L.; Chodos, A. A.

    1971-01-01

    Apollo 14 crystalline rocks (14053 and 14310) and crystalline rock fragments (14001,7,1; 14001,7,3; 14073; 14167,8,1 and 14321,191,X-1) on which Rb/Sr, Ar-40/Ar-39, or cosmic ray exposure ages have been determined by our colleagues were studied with the electron microprobe and the petrographic microscope. Rock samples 14053 and 14310 are mineralogically and petrologically distinct from each other. On the basis of mineralogic and petrologic characteristics all of the fragments, except 14001,7,1, are correlative with rock 14310. Sample 14073 is an orthopyroxene basalt with chemical and mineralogic affinities to ?KREEP,' the ?magic' and ?cryptic' components. Fragment 14001,7,1 is very similar to Luny Rock I.

  5. PETRO.CALC.PLOT, Microsoft Excel macros to aid petrologic interpretation

    USGS Publications Warehouse

    Sidder, G.B.

    1994-01-01

    PETRO.CALC.PLOT is a package of macros which normalizes whole-rock oxide data to 100%, calculates the cation percentages and molecular proportions used for normative mineral calculations, computes the apices for ternary diagrams, determines sums and ratios of specific elements of petrologic interest, and plots 33 X-Y graphs and five ternary diagrams. PETRO.CALC.PLOT also may be used to create other diagrams as desired by the user. The macros run in Microsoft Excel 3.0 and 4.0 for Macintosh computers and in Microsoft Excel 3.0 and 4.0 for Windows. Macros provided in PETRO.CALC.PLOT minimize repetition and time required to recalculate and plot whole-rock oxide data for petrologic analysis. ?? 1994.

  6. A detailed petrological analysis of hydrated, low-nickel, nonchondritic stratospheric dust particles

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1992-01-01

    A detailed petrological analysis of three low-Ni, K-bearing, nonchondritic stratospheric dust particles is performed, and these particles are compared to products of high-energy, explosive (Plinian-type) volcanic events. The analytical electron microscope (AEM) analyses show pervasive layer silicates, carbonate and goethite, and chemical fractionation in the matrix of these particles similar to hydrothermal alteration in volcanic ejecta. Along with low Ni content and the presence of potassium, the texture and mineralogy of particles L2001-18, L2001-20, and L2002 C2 are similar to at least two nonchondritic stratospheric dust particles of the igneous subgroup for which an extraterrestrial origin has been suggested based on their minor- and trace-element abundances. The petrological characteristics of some low-Ni, K-bearing nonchondritic stratospheric dust particles supports a probable terrestrial volcanic origin, but the AEM data alone cannot exclude an extraterrestrial origin for these particles.

  7. MinChem: A Prototype Petrologic Database for Hanford Site Sediments

    SciTech Connect

    Mackley, Rob D.; Last, George V.; Serkowski, John A.; Middleton, Lisa A.; Cantrell, Kirk J.

    2010-09-01

    A prototype petrologic database (MinChem) has been under continual development for several years. MinChem contains petrologic, mineralogical, and bulk-rock geochemical data for Hanford Site sediments collected over multiple decades. The database is in relational form and consists of a series of related tables modeled after the Hanford Environmental Information System HEIS (BHI 2002) structures. The HEIS-compatible tables were created in anticipation of eventual migration into HEIS, or some future form of HEIS (e.g. HEIS-GEO). There are currently a total of 13,129 results in MinChem from 521 samples collected at 381 different sampling sites. These data come from 19 different original source documents published and unpublished (e.g. letter reports) between 1976 and 2009. The data in MinChem consist of results from analytical methods such as optical and electron microscopy, x-ray diffraction, x-ray fluorescence, and electron probe microanalysis.

  8. Mineralogy, petrology and geochemistry of carbonaceous chondritic clasts in the LEW 85300 polymict eucrite

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Hewins, R. H.; Mittlefehldt, D. W.; Lindstrom, M. M.; Xiao, X.; Lipschutz, M. E.

    1992-01-01

    We have performed a detailed petrologic and mineralogic study of two chondritic clasts from the polymict eucrite Lewis Cliff (LEW) 85300, and performed chemical analyses by INAA and RNAA on one of these. Petrologically, the clasts are identified and are composed of dispersed aggregates, chondrules, and chondrule fragments supported by matrix. The aggregates and chondrules are composed of olivine, orthopyroxene, plus some diopside. The matrix consists of fine-grained olivine, and lesser orthopyroxene and augite. Fine-grained saponite is common in the matrix. The bulk major composition of the clast studied by INAA and RNAA shows unusual abundance patterns for lithophile, siderophile and chalcophile elements but is basically chondritic. The INAA/RNAA data preclude assignment of the LEW 85300,15 clast to any commonly accepted group of carbonaceous chondrite.

  9. Age, field, and petrological relationships of the Hyde School Gneiss, Adirondack lowlands, New York: Criteria for an intrusive igneous origin

    SciTech Connect

    McLelland, J. ); Perham, A. ); Chiarenzelli, J.

    1992-01-01

    Alaskitic and tonalitic rocks constituting Hyde School Gneiss (HSG) occur in 14 domical bodies in the Adirondack lowlands. Recent models have interpreted these bodies as metamorphosed rhyolitic and dacitic ash-flow deposits forming the basal member of a regional stratigraphic package. In contrast, this paper presents criteria and evidence for an intrusive origin for HSG. Field evidence includes intrusion breccias and complex crosscutting relationships involving mafic layers resembling synplutonic dikes. Petrologic constraints supporting an intrusive origin include: (1) the common occurrence of quartz-mesoperthite hypersolvus assemblages; (2) magmatic features in tonalitic, trondhjemitic, and alaskitic facies, (3) local occurrences of orthopyroxene in all facies of HSG; and (4) the development of marginal garnet-sillimanite gneiss with corundum-spinel-garnet-sillimanite assemblages yielding paleotemperatures of 780-810C and interpreted as restite remaining after anatexis of country rock metapelite by intrusions of hypersolvus granitoids. U-Pb zircon ages reported here suggest that the majority of the HSG was intruded at ca. 1230 Ma, contemporaneous with high-grade metamorphic activity in the Adirondacks and elsewhere in the SW sector of the Grenville Province. Geochronological evidence from a leucogranitic rock crosscutting metasediments on Wellesley Island suggest that these metasediments are older than 1416 {plus minus} 5 Ma.

  10. Petrological cannibalism: the chemical and textural consequences of incremental magma body growth

    NASA Astrophysics Data System (ADS)

    Cashman, Kathy; Blundy, Jon

    2013-09-01

    fluxing the reservoir with CO2-rich vapors that are either released from deeper in the system or transported with the recharge magma. Temperature fluctuations of 20-40 °C, on the other hand, are an inevitable consequence of incremental, or pulsed, assembly of crustal magma bodies wherein each pulse interacts with ancestral, stored magmas. We venture that this "petrological cannibalism" accounts for much of the plagioclase zoning and textural complexity seen not only at Mount St. Helens but also at arc magmas generally. More broadly we suggest that the magma reservoir below Mount St. Helens is dominated by crystal mush and fed by frequent inputs of hotter, but compositionally similar, magma, coupled with episodes of magma ascent from one storage region to another. This view both accords with other independent constraints on the subvolcanic system at Mount St. Helens and supports an emerging view of many active magmatic systems as dominantly super-solidus, rather than subliquidus, bodies.

  11. Luna 16 - Relative proportions and petrologic significance of particles in the soil from Mare Fecunditatis.

    NASA Technical Reports Server (NTRS)

    Reid, J. B., Jr.; Taylor, G. J.; Marvin, U. B.; Wood, J. A.

    1972-01-01

    Some 2380 lithic and vitreous particles from levels A and G of the Luna 16 core-tube sample were classified. The relative proportions of particle types from each of the two layers are reported, and some petrological and mineralogical aspects of the lithic and vitreous components of the lunar regolith are discussed. Possible sources of the particles in the Luna 16 soil are examined.

  12. Studies of Brazilian meteorites. XIV - Mineralogy, petrology, and chemistry of the Conquista, Minas Gerais, chondrite

    NASA Technical Reports Server (NTRS)

    Keil, K.; Kirchner, E.; Gomes, C. B.; Jarosewich, E.; Murta, R. L. L.

    1978-01-01

    The Conquista chondrite is described and classified as an H4. The mineral composition is reported. H-group classification is based on described microscopic, electron microprobe, and bulk chemical studies. The evidence for petrologic type 4 classification includes the pronounced well-developed chondritic texture; the slight compositional variations in constituent phases; the high Ca contents of pyroxene and the presence of pigeonite; glassy to microcrystalline interstitial material rich in alkalis and SiO2; and twinned low-Ca clinopyroxene.

  13. Apollo 17, Station 6 boulder sample 76255 - Absolute petrology of breccia matrix and igneous clasts

    NASA Technical Reports Server (NTRS)

    Warner, J. L.; Phinney, W. C.; Simonds, C. H.

    1976-01-01

    The matrix of 76255 is the finest-grained, most clast-laden, impact-melt polymict breccia sampled from the Station 6 boulder. The paper speculates on how the matrix of 76255 fits into and enhances existing thermal models of breccia lithification. Emphasis is on the detailed petrology of five lithic clasts, two of which display mineralogical and textural affinities to mare basalts, while three, a gabbro, a norite, and a troctolite are considered primitive plutonic rocks.

  14. Report of the Workshop on Unmixing the SNCs: Chemical, Isotopic, and Petrologic Components of Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H. (Editor); Herd, Christopher D. K. (Editor)

    2002-01-01

    Geochemical and petrologic studies of the Martian meteorites (nicknamed the SNCs) have proliferated in the past few years, from a wealth of new samples and the perfection of new analytical methods. An intriguing result from these studies is that the chemical and isotopic compositions of the Martian meteorites, all basalts or derived from basaltic magma, can be modeled as mixtures of a limited number of components. These mixing components were the focus of the workshop.

  15. Mineralogy, Petrology, Chronology, and Exposure History of the Chelyabinsk Meteorite and Parent Body

    NASA Technical Reports Server (NTRS)

    Righter, K.; Abell, P.; Agresti, D.; Berger, E. L.; Burton, A. S.; Delaney, J. S.; Fries, M. D.; Gibson, E. K.; Harrington, R.; Herzog, G. F.; Keller, L. P.; Locke, D.; Lindsay, F.; McCoy, T. J.; Morris, R. V.; Nagao, K.; Nakamura-Messenger, K.; Niles, P. B.; Nyquist, L.; Park, J.; Peng, Z. X.; Shih, C. Y.; Simon, J. I.; Swisher, C. C., III; Tappa, M.

    2015-01-01

    The Chelyabinsk meteorite fall on February 15, 2013 attracted much more attention worldwide than do most falls. A consortium led by JSC received 3 masses of Chelyabinsk (Chel-101, -102, -103) that were collected shortly after the fall and handled with care to minimize contamination. Initial studies were reported in 2013; we have studied these samples with a wide range of analytical techniques to better understand the mineralogy, petrology, chronology and exposure history of the Chelyabinsk parent body.

  16. Research in volcanic geology, petrology and planetary science at MIT, 1969 to 1974

    NASA Technical Reports Server (NTRS)

    Mcgetchin, T. R.

    1974-01-01

    The behavior of volcanoes was studied by geologic mapping, petrologic investigations of lava and xenoliths, physical measurements, and theoretical modelling. Field observations were conducted in Alaska (Nunivak Island), Iceland, Hawaii (Mauna Kea), Italy (Etna, Stromboli), and Arizona. The results are discussed and compared with known data for lunar and planetary gelogy. Field methods used for the volcano research are cited and a list is given of all participating scientists and students. Publications and abstracts resulting from the research are also listed.

  17. Petrology and Geochemistry of New Paired Martian Meteorites Larkman Nunatak 12240 and Larkman Nunatak 12095

    NASA Technical Reports Server (NTRS)

    Funk, R. C.; Peslier, A. H.; Brandon, A. D.; Humayun, M.

    2016-01-01

    Two of the latest Martian meteorites found in Antarctica, paired olivine-phyric shergottites LAR 12240 and LAR 12095, are described in order to decipher their petrological context, and place constraints on the geological history of Mars. This project identifies all phases found in LAR 12240 and 12095 and analyzes them for major and trace elements. The textural relationships among these phases are examined in order to develop a crystallization history of the magma(s) that formed these basalts.

  18. A summary of the petrology and geochemistry of pristine highlands rocks

    NASA Technical Reports Server (NTRS)

    Norman, M. D.; Ryder, G.

    1979-01-01

    The petrology and geochemistry of pristine lunar highlands rock samples consisting of ferroan anorthosites, norites, troctolites, spinel troctolites/dunite/lherzolite, and KREEP, are described. In addition, petrographic and chemical evidence is presented which shows that low-siderophile rocks are the result of endogenous igneous activity and not impact melt differentiation. For example, these rocks contain Fe-metal as a late-crystallizing phase, and have W/La ratios higher than polymict breccias.

  19. Mineralogy and petrology of basaltic fragments from the Luna 24 drill core

    NASA Technical Reports Server (NTRS)

    Coish, R. A.; Taylor, L. A.

    1978-01-01

    The petrology of rock fragments and monomineralic grains from Luna 24 samples is described, and a petrogenetic scheme for the derivation of Mare Crisium basalts is presented. Components of the rock fragments include subophitic basalts, metabasalts, late-stage fragments, olivine vitrophyres, and non-mare lithic fragments of possible cumulate origin. Among the monomineralic grains (which are much more abundant than the rock fragments) are pyroxene, plagioclase, olivine, ilmenite and native Fe.

  20. Evidence of a close link between petrology and isotope records: constraints from SEM, EMP, TEM and in situ 40Ar- 39Ar laser analyses on multiple generations of white micas (Lanterman Range, Antarctica)

    NASA Astrophysics Data System (ADS)

    Di Vincenzo, Gianfranco; Ghiribelli, Barbara; Giorgetti, Giovanna; Palmeri, Rosaria

    2001-10-01

    K-Ar ages from white mica are commonly interpreted to record cooling below a certain temperature with the implicit assumption that all the requirements of the volume diffusion theory are fulfilled. Nevertheless, studies on metamorphic white micas have highlighted discrepancies with previously inferred closure temperatures and have evidenced a close link between petrology and argon isotope age records. This study uses the in situ 40Ar- 39Ar laserprobe method in conjunction with scanning electron microscopy, electron microprobe and transmission electron microscopy (TEM) techniques to examine the relations between argon isotope records and microtextural, microchemical and microstructural variations in white mica. Gneisses and micaschists belonging to three different tectono-metamorphic complexes of the Lanterman Range (Antarctica) contain multiple generations of potassic white micas and are well-suited to investigate the relation between petrology and argon dating. Texturally resolvable white mica generations show microchemical and microstructural (TEM scale) variations that suggest development under different P- T deformation regimes, ranging from an eclogite facies stage down to low greenschist facies conditions. In situ 40Ar- 39Ar laserprobe analyses on white mica samples from the three complexes reveal a complex intragrain and intergrain spatial distribution of argon ages which is closely linked to microtextural, microchemical and microstructural variations: texturally, compositionally and microstructurally older generations yield older ages whereas the younger ones yield younger ages. Results show that in the absence of re-crystallisation, white mica preserves argon isotope records pertaining to the high-pressure stage which survived amphibolite retrogression at temperatures of 550-650°C. The texture, petrology and isotope record of white micas in the studied samples preserve a nearly continuous record of P, T and deformation history within the same orogenic

  1. Isotopic Constraints on the Petrology of Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    2005-01-01

    The SNC (martian) meteorites exhibit complex isotopic characteristics that yield information both about the ages of individual meteorites as well as information about the petrogenetic processes that produced both individual samples and about the origins of suites and sub-suites within the SNC clan. Here I review these data, reiterate earlier interpretations, and offer some new conclusions.

  2. The genesis of the northern Kettle Moraine, Wisconsin

    NASA Astrophysics Data System (ADS)

    Carlson, A. E.; Mickelson, D. M.; Principato, S. M.; Chapel, D. M.

    2005-04-01

    Interpreting past glacial dynamics from the glacial record requires that the depositional environments of glacial sediments and landforms be understood. In the case of interlobate deposits, models that incorporate various components of pro, supra and subglacial deposition have been developed and tested in the northern Kettle Moraine (nKM), Wisconsin; a large interlobate deposit that formed between the Green Bay and Lake Michigan lobes of the Laurentide Ice Sheet during the last deglaciation. In this paper, we interpret a new genesis for the nKM using sediment analysis and distribution along with landform distribution. In Sheboygan County, the nKM consists of two steep-sided, high-relief, hummocky ridges separated by a low elevation and low-relief central axis. Gravel in the bounding hummocky ridges is well-sorted and well-rounded. Some bedding is collapsed. Large, isolated moulin kames are restricted to the axis area and composed of relatively poorly sorted, more angular gravel and diamicton. The distribution of these different sediments and landforms are explained by the accumulation of supraglacial debris that insulated the ice below the axis of the nKM, while the melting of cleaner ice on either side formed channels on the ice surface. As deglaciation proceeded, a substantial thickness of well-rounded, stream-deposited sand and gravel accumulated on ice in the bounding channels. Eventual collapse of this sediment formed the two hummocky ridges. Poorly sorted debris along the axis fell and slid into moulins and larger collapse areas in the ice. Thus, differential debris insulation and ice ablation controlled the mainly supraglacial deposition of this part of the nKM.

  3. Project Genesis: Mars in situ propellant technology demonstrator mission

    NASA Technical Reports Server (NTRS)

    Acosta, Francisco Garcia; Anderson, Scott; Andrews, Jason; Deger, Matt; Hedman, Matt; Kipp, Jared; Kobayashi, Takahisa; Marcelo, Mohrli; Mark, Karen; Matheson, Mark

    1994-01-01

    Project Genesis is a low cost, near-term, unmanned Mars mission, whose primary purpose is to demonstrate in situ resource utilization (ISRU) technology. The essence of the mission is to use indigenously produced fuel and oxidizer to propel a ballistic hopper. The Mars Landing Vehicle/Hopper (MLVH) has an Earth launch mass of 625 kg and is launched aboard a Delta 117925 launch vehicle into a conjunction class transfer orbit to Mars. Upon reaching its target, the vehicle performs an aerocapture maneuver and enters an elliptical orbit about Mars. Equipped with a ground penetrating radar, the MLVH searches for subsurface water ice deposits while in orbit for several weeks. A deorbit burn is then performed to bring the MLVH into the Martian atmosphere for landing. Following aerobraking and parachute deployment, the vehicle retrofires to a soft landing on Mars. Once on the surface, the MLVH begins to acquire scientific data and to manufacture methane and oxygen via the Sabatier process. This results in a fuel-rich O2/CH4 mass ratio of 2, which yields a sufficiently high specific impulse (335 sec) that no additional oxygen need be manufactured, thus greatly simplifying the design of the propellant production plant. During a period of 153 days the MLVH produces and stores enough fuel and oxidizer to make a 30 km ballistic hop to a different site of scientific interest. At this new location the MLVH resumes collecting surface and atmospheric data with the onboard instrumentation. Thus, the MLVH is able to provide a wealth of scientific data which would otherwise require two separate missions or separate vehicles, while proving a new and valuable technology that will facilitate future unmanned and manned exploration of Mars. Total mission cost, including the Delta launch vehicle, is estimated to be $200 million.

  4. Metalloproteinase inhibition prevents inhibitory synapse reorganization and seizure genesis.

    PubMed

    Pollock, Emily; Everest, Michelle; Brown, Arthur; Poulter, Michael O

    2014-10-01

    The integrity and stability of interneurons in a cortical network are essential for proper network function. Loss of interneuron synaptic stability and precise organization can lead to disruptions in the excitation/inhibition balance, a characteristic of epilepsy. This study aimed to identify alterations to the GABAergic interneuron network in the piriform cortex (PC: a cortical area believed to be involved in the development of seizures) after kindling-induced seizures. Immunohistochemistry was used to mark perineuronal nets (PNNs: structures in the extracellular matrix that provide synaptic stability and restrict reorganization of inhibitory interneurons) and interneuron nerve terminals in control and kindled tissues. We found that PNNs were significantly decreased around parvalbumin-positive interneurons after the induction of experimental epilepsy. Additionally, we found layer-specific increases in GABA release sites originating from calbindin, calretinin, and parvalbumin interneurons, implying that there is a re-wiring of the interneuronal network. This increase in release sites was matched by an increase in GABAergic post-synaptic densities. We hypothesized that the breakdown of the PNN could be due to the activity of matrix metalloproteinases (MMP) and that the prevention of PNN breakdown may reduce the rewiring of interneuronal circuits and suppress seizures. To test this hypothesis we employed doxycycline, a broad spectrum MMP inhibitor, to stabilize PNNs in kindled rats. We found that doxycycline prevented PNN breakdown, re-organization of the inhibitory innervation, and seizure genesis. Our observations indicate that PNN degradation may be necessary for the development of seizures by facilitating interneuron plasticity and increased GABAergic activity. PMID:24946277

  5. Crystal structure and genesis of the hydrated analog of rastsvetaevite

    NASA Astrophysics Data System (ADS)

    Rastsvetaeva, R. K.; Aksenov, S. M.; Rozenberg, K. A.

    2015-11-01

    The crystal structure of the hydrated analog of the mineral rastsvetaevite (tentatively called "hydrorastsvetaevite"), which was found by A.P. Khomyakov in ultraagpaitic pegmatites at the Rasvumchorr Mountain of the Khibiny alkaline massif (Kola Peninsula), has been determined by single crystal X-ray diffraction. The trigonal unit-cell parameters are as follows: a = 14.2812(2) Å, c = 60.533(5) Å, V = 10691.54(3) Å3, sp. gr. R3 m. The structure was refined to R = 5.9% in the isotropic and anisotropic approximation of atomic displacement parameters based on 2068 ref lections with | F| > 3σ( F). "Hydrorastsvetaevite" is on the whole analogous to other 24-layer representatives of the eudialyte group (called "megaeudialytes"), but is characterized by a high potassium content and is distinguished from other potassium-rich minerals (rastsvetaevite, davinciite, and andrianovite) by low sodium and alkaline-earth metal content, as well as by a high degree of hydration accompanied by the insertion of H3O groups, which partially or completely replace large cations. The idealized formula of "hydrorastsvetaevite" ( Z = 3) is (Na11(H3O)11K6(H2O)1.5Sr)Ca12Fe3Na2MnZr6Si52O144(OH)4.5Cl3.5(H2O)0.5. In alkaline pegmatites, "hydrorastsvetaevite" occurs as a secondary mineral developed from the original rastsvetaevite through decationation and hydration. The characteristic features of the genesis of eudialyte-group minerals containing potassium as a species-forming cation are discussed in terms of the concept of transformational mineral species. an]Mis||Original Russian Text R.K. Rastsvetaeva, S.M. Aksenov, K.A. Rozenberg, 2015, published in Kristallografiya, 2015, Vol. 60, No. 6, pp. 897-905.

  6. Genesis of the Costilla Reservoir sill, New Mexico

    SciTech Connect

    McDuffie, S.; Marsh, B.D. . Dept. of Earth and Planetary Sciences)

    1992-01-01

    The Costilla Reservoir sill is a 220 m-thick, tabular hypabyssal intrusion in the Latir volcanic field of north central New Mexico. This late Oligocene body consists of olivine-bearing basaltic andesite ranging from 53 to 57% SiO[sub 2]. The chemical variations are not due to in-situ crystal settling, for modal and whole rock chemical profiles reveal no such redistribution. Settling calculations predict a cumulate pile in such a large igneous body, so the absence of settling suggests that a single, thick molten sheet never existed. Hence the authors conclude emplacement was episodic, extending over a period commensurate with solidification time (100+ years). The lack of internal chill zones precludes injection over a significantly longer period. Since no crystals were redistributed post-emplacement, the chemical differences within the body result from the injection of initially heterogeneous magma. The first pulse of magma, which is represented by the 10--20 m nearest each contact, differs from the bulk of the sill in FeO[sub total], Sc, and average An content of plagioclase. The subsequent injections are not chemically uniform, but their variations are gradational. The chemical disparities within the Costilla magma cannot be fully explained by preplacement fractionation of the major phases (plag, olivine, cpx, opx). The heterogeneity may have existed from the time and place of magma genesis, which appears to be in the lower crust. The majority of pyroxene and feldspar phenocrysts exhibit features (extensive fracturing, disequilibrium textures) suggesting they did not crystallize directly from this magma. Rather, they may be restitic grains inherited from a partially melted source area. Additionally, some of these crystals have been spawned by the abundant supply of xenoliths, some of which were disaggregating in the magma.

  7. The genesis solar-wind sample return mission

    SciTech Connect

    Wiens, Roger C

    2009-01-01

    , each theory predicting a different solar isotopic composition and each invoking a different early solar-system process to produce the heterogeneity. Other volatiles such as C, N, and H may also have experienced similar effects, but with only two isotopes it is often impossible to distinguish with these elements between mass-dependent fractionation and other effects such as mixing or mass-independent fractionation. Table 1 provides a summary of the major measurement objectives of the Genesis mission. Determining the solar oxygen isotopic composition is at the top of the list. Volatile element and isotope ratios constitute six of the top seven priorities. A number of disciplines stand to gain from information from the Genesis mission, as will be discussed later. Based on the Apollo solar-wind foil experiment, the Genesis mission was designed to capture solar wind over orders of magnitude longer duration and in a potentially much cleaner environment than the lunar surface.

  8. Jovian Dynamics. Part 1: Vortex Stability, Structure, and Genesis.

    NASA Astrophysics Data System (ADS)

    Williams, G. P.

    1996-09-01

    The vertical of Jupiter's atmosphere is probed and isolated by evaluating the stability characteristics of planetary vortices over a wide parameter range. The resulting structures lead to simulating the genesis of single and multiple vortex states in Part I of this paper and the genesis of an equatorial superrotation and midlatitudinal multiple jets in Part II.The stability and genesis of baroclinic Rossby vortices, the vortices associated with long solitary Rossby waves in a stratified fluid, are studied numerically using a primitive equation model with Jovian and oceanic parameters and hypo-thermal structures. Vortex stability, that is, coherence and persistence, depends primarily upon latitude location and vertical structure and is used to deduce possible stratifications for Jupiter's atmosphere. The solutions suggest that Jupiter's large-scale motions are confined to a layer of depth h and are bounded by an abyss with an impermeable interface at a depth H, such that h/H1/20. Consequently, they also extend earlier results derived with the reduced-gravity, shallow-water model, particularly the explanation for the origin, uniqueness, and longevity of the Great Red Spot (GRS).Beginning at the equator, stable anticyclones are seen to exist only when they have the Hermitian latitudinal form, the Korteweg-deVries longitudinal form, the confined exponential vertical structure exp(Nz/H), and the amplitude range as prescribed by the analytical theory of Marshall and Boyd for N=8. Soliton interactions occur between equatorial vortices of similar horizontal and vertical form.In middle and low latitudes, shallow anticyclones with an exponential structure of N=20 exist quasi-stably for a variety of sizes. Such vortices remain coherent but tend to migrate equatorward (where they disperse) at rates that depend upon their size, location, and vertical structure: large and medium anticyclones propagate primarily westward while migrating slowly, whereas small storms just migrate

  9. Interdecadal change in typhoon genesis condition over the western North Pacific

    NASA Astrophysics Data System (ADS)

    Choi, Yumi; Ha, Kyung-Ja; Ho, Chang-Hoi; Chung, Chul Eddy

    2015-12-01

    The interdecadal changes in typhoon (categories 1-3) frequency and its genesis condition over the western North Pacific during the period of 1979-2011 are investigated with consideration for discrepancies among best track datasets. To tide over data uncertainty, a detection-produced dataset is utilized as a homogeneous dataset with five available best track datasets. Typhoon experienced interdecadal changes around the mid-1990s and the mid-2000s in their genesis conditions. Even under the oceanic warm state, typhoon frequency has decreased since the mid-1990s, showing a northwestward movement of its genesis location over the main formation region. The eastward gradient of vertical wind shear is the most significant factor for the change in typhoon genesis condition in recent decades. The vertical wind shear behavior is strongly linked with zonal asymmetry of local SST. We demonstrate that a westward gradient of local SST is the most important modulator of the recent typhoon behavior through the movement of favorable genesis location. The present results indicate that the horizontal distribution, not magnitude, of local SST can be a key factor for prediction of future typhoon activity, thus contributing to natural disaster mitigation and climate change adaptation strategies.

  10. Role of Tropical Waves in Tropical Cyclone Genesis over the Western North Pacific

    NASA Astrophysics Data System (ADS)

    Wu, Liang; Takahashi, Masaaki

    2016-04-01

    The present study investigates the relationship between the tropical waves and the tropical cyclone (TC) genesis over the western North Pacific (WNP) for the period 1979-2011. Five wave types are considered in this study. It is shown that the TC genesis is strongly related to enhanced low-level vorticity and convection of tropical wave in all wave types but with significant difference in the TC modulation between wave dynamic and thermodynamic components. More TCs tend to form in regions of each wave with overlapping cyclonic vorticity and active convection. About 83.2% of TCs form within active phase of tropical waves, mainly in either one or two wave types. Each wave type is accounts for about 30% of all TC geneses except for the Kelvin waves that account for only 25.2% of TC geneses. The number of each wave type-related TC genesis consistently varies seasonally with peak in the TC season (July-November), which is attributed to the combined effect of both active wave probability and intensity change. The interannual variation of the TC genesis is well reproduced by the tropical wave-related TC genesis, especially in the region to east of 150°E. An eastward extension of the enhanced monsoon trough coincides with increased tropical wave activity by accelerated wave-mean flow interaction.

  11. To the soil genesis in tundra-forest ecotone belt in the Northeastern European Russia

    NASA Astrophysics Data System (ADS)

    Shakhtarova, Olga; Rusanova, Galina; Lapteva, Elena

    2013-04-01

    and cryogenic processes. Upper soil has signs of present-day "cryogenic" evolution phase: features of migration of Al-Fe-humus complexes down profile. Middle and lower part of soil profile have features of taiga soil formation occurred during the Middle Holocene. Taiga stage of soil formation could be diagnosed by the presence of fragments of clay cutans and humic pedorelics. Destruction of cutan complex is a result of sharp climatic cooling occurred in Subboreal period when cryomethamorphic horizon was formed. The similar type of profile structure could be explained by specifity of soil evolution in the transition zone impacted by repeated tree line shifts during Holocene. The study was supported by Program of UD RAS, project #12--4-1004 «Soil genesis in Cryolithozone of the European North-East on Abrupt Climate & Human-induced impact».

  12. Sedimentary genesis and lithostratigraphy of Neoproterozoic megabreccia from Mufulira, Copperbelt of Zambia

    NASA Astrophysics Data System (ADS)

    Wendorff, Marek

    2005-07-01

    separated by two intervals of sedimentary breccia composed of allochthonous Roan blocks interpreted as mass-wasting debris redeposited into the basin by high-volume sediment-gravity flows. Sedimentary features are the primary characteristics of the conglomerate interbeds in the Roan succession and of the overlying megabreccia (olistostrome) sequence. Both lithological associations are slightly sheared and brecciated in places, but stratigraphic continuity is retained throughout their succession. The olistostrome is deformed by an open fold, the upper limb of which is truncated by and involved in a shear zone that extends upwards into Mwashya Subgroup strata thrust above. Based on the sedimentary genesis of the megabreccia, local tectonostratigraphic relations and correlation with the succession present in the Kafue anticline to the west, the Mwashya Subgroup, formerly considered as a twofold unit, is redefined here as a three-part succession. The lower Mwashya consists of an olistostrome complex defined as the Mufulira Formation, the middle Mwashya (formerly lower Mwashya) is a mixed succession of siliciclastic and carbonate strata locally containing silicified ooids and tuff interbeds, and the term upper Mwashya is retained for a succession of black shales with varying proportions of siltstone and sandstone interlayers. The sedimentary genesis and stratigraphic relations of the megabreccia at Mufulira imply that the position and tectonostratigraphic context of the Katangan Cu and Cu-Co orebodies hosted in megablocks associated with fragmental rocks, which were in the past interpreted as tectonic friction breccias, need to be critically re-assessed in the whole Lufilian arc.

  13. Petrology, geochemistry and modelling of the granulitic-ultramafic rocks in Beni Bousera (Rif, Morocco): implications for direct crust-mantle interactions and melt-extraction systems

    NASA Astrophysics Data System (ADS)

    Manthei, C. D.; Álvarez-Valero, A.; Jagoutz, O. E.

    2011-12-01

    both key granitic dykes/inclusions around the granulite-ultramafic contact, and zircon/monazite within their microtextural context in the complex metamorphic history of the granulites, for example, the preservation of early high-pressure assemblages (e.g. Grt+Ky+Rt) together with later low-pressure assemblages (e.g. Crd+Bt+Spl). The field-observations and results of the phase diagram modeling -and P-T history- will be compared to thermo-mechanical numerical modeling to ensure that the very rapid ascent of the ultramafic material from the asthenosphere to the upper-crust is in-line with our current understanding of Mediterranean tectonics. We are confident that this multidisciplinary research approach -by combining field geology, petrology, tectonics, physics, thermodynamics and numerical modeling- is the best method to address unanswered questions in Earth Sciences.

  14. Microcracks, micropores, and their petrologic interpretation for 72415 and 15418

    NASA Technical Reports Server (NTRS)

    Richter, D.; Simmons, G.; Siegfried, R.

    1976-01-01

    Lunar samples 72415 and 15418 have complex microstructures that indicate a series of fracturing and healing events. Both samples contain relatively few open microcracks but many sealed and healed microcracks. Dunite 72415 contains abundant healed cracks that formed tectonically, symplectic intergrowths spatially and probably genetically related to microcracks, and a cataclastic matrix that has been extensively sintered. Metamorphosed breccia 15418 contains many post-metamorphic healed cracks, large shock induced cracks that have been sealed with glass, and a few younger, thin, open shock induced cracks.

  15. Rockyhock and Kimbel Carolina Bays: Extraterrestrial Impact or Terrestrial Genesis?

    NASA Astrophysics Data System (ADS)

    Lecompte, M. A.; Branch, B. D.; Barnes, L.; Hall, C.

    2009-12-01

    Evidence for the harsh climate prevalent during the Last Glacial Maximum (LGM) are seen in topographical features visible south of the ice sheet margin in the uplands and coastal regions of the southeastern United States. Among the features attributed to ice age climate are numerous elliptical, shallow depressions called collectively Carolina Bays, hypothesized to have been formed by “blow outs” of loose sediment by the strong, sustained winds and arid, cold climate characteristic of glacial epochs (Raisz, 1934, Johnson, 1942 and Kaczorowski, 1977). This view eclipsed the 1933 proposition by Melton and Schriever, and expanded by Prouty (1934, 1953), that extraterrestrial debris produced by an aerial meteorite or comet explosion in the vicinity of the Great Lakes during the late Pleistocene formed the bays. 12,900 years ago, post-LGM warming was interrupted by a return to a glacial climate that persisted for over 1,000 years. The events precipitating the cooling, known as the Younger Dryas (YD), are the subject of debate. Recently Firestone et. al. (2007) proposed that an impact in the Laurentide ice sheet by a fragmented comet might have simultaneously initiated the YD and formed the Carolina Bays. Carbon 14 dating and pollen analysis of core samples taken from Rockyhock Bay, in Chowan County, NC, by Whitehead (1980) indicate a pre-YD genesis. However, a number of the bays have been found to contain materiel associated with extraterrestrial impacts including carbon and magnetic spherules, glass-like carbon, charcoal and nanodiamonds (Firestone, et. al. 2007). The discoveries reinvigorated the debate over the bay’s origins. Were the bays created by an impact or were they merely receptacles for impact materiel injected into the environment. If created before the YD, the bays would have experienced episodic post-formation modification due to cold, dry, windy periods alternating with warm, moist and calmer climatic conditions. Carolina Bays would thus

  16. Peculiar Moving Magnetic Features Observed With the Flare Genesis Experiment

    NASA Astrophysics Data System (ADS)

    Bernasconi, P. N.; Rust, D. M.; Georgoulis, M. K.; LaBonte, B. J.; Schmieder, B.

    2001-05-01

    With the Flare Genesis Experiment (FGE), a balloon-borne 80-cm solar telescope, we observed the active region NOAA 8844 on January 25, 2000 for several hours. FGE was equipped with a vector polarimeter and a lithium-niobate Fabry-Perot narrow-band filter. It recorded time series of filtergrams, vector magnetograms, and dopplergrams at the CaI 6122.2 Angstroms line, as well as Hα filtergrams, with a cadence between 2.5 and 7.5 minutes. At the time of the observations NOAA 8844 was located at approximately 5 deg N, 30 deg W. It was a new flux emergence that first appeared on the solar disk two days before and was still showing a very dynamic behavior. Its two main polarity parts were rapidly moving away from each other and new magnetic flux was constantly emerging from its center. Here we describe the structure and behavior of peculiar small moving magnetic dipoles (called moving magnetic features MMF's) that we observed near the trailing negative polarity sunspot of NOAA 8844. Presentations by D. M. Rust, and by M. K. Georgoulis at this meeting will focus on other aspects of the same active region. The MMF's took the form of small dipoles that first emerged into the photosphere near the center of a supergranular cell located next to the main trailing flux concentration. They rapidly migrated towards the spot, following the supergranular flow. The two polarities of the little dipoles did not separate; they moved together with same speed and in the same direction. The dipoles were oriented parallel to their motion toward the negative spot, with the positive polarity always leading. MMF's usually move away from sunspots, and their orientation is the reverse of what we see here. In addition, we noted that the dipole structure was not symmetric. The field lines of the trailing part of the MMF's (negative polarity) were always much more perpendicular to the local horizontal than the ones of the leading part. The trailing part looked more compact and circular, while the

  17. Genesis and formation oil and gas fields (Azerbaijan)

    NASA Astrophysics Data System (ADS)

    Poletayev, Alexander

    2010-05-01

    The large amount of material of HC isotope composition of over 330 samples allow to restore the history of oil and gas deposits formation within the South-Caspian Depression. Maps of isotope composition changes according to area extent, as well as graphs of HC distribution depending upon stratigraphic age, including rocks, graphs of isotope composition change on sampling depth were compiled for HC study and oil-gas deposits formation. Comparison of mud volcanoes gases, oil and gas fields, gas-hydrates and bottom sediments were conducted. Gases genesis according to M. Shoelle and A. James methodic were studied. Model of area paleoconstruction was studied. Two stages of formation were distinguished as a result of gases study of various forms of their manifestation (gases of mud volcanoes, oil and gas fields, gas hydrate, bottom sediments) as well as isotope gases composition distribution in area of extent including stratigraphic age of deposits, depth of sampling and application of M. Shoelle and A. James. There were determined basic ways of HC migration as well as estimated oil-gas content prospective. The first stage has begun in the underlying PS deposits and continued up to PS deposits. At this stage one various kind of tectonic fluctuations can observed. The second stage of HC formation has started from PS and characterised with a change of geodynamic conditions in region. Avalanche sedimentation, predominance of descending movements over ascending ones promoted the accumulation of thick sediments in PS age. As a result of sediments accumulation and tectonic processes (down warping) in the deep-seated basin led to the complication of thermobaric conditions in the sedimentary series. The studied chemical and HC gases isotope composition showed that basic source of oil and gas formation is located in the deep areas of central and near-flank parts of depression. HC migration has mainly occurred upward. Study of HC migration trend in time and area as well as areas

  18. Genesis Contingency Planning and Mishap Recovery: The Sample Curation View

    NASA Technical Reports Server (NTRS)

    Stansbery, E. K.; Allton, J. H.; Allen, C. C.; McNamara, K. M.; Calaway, M.; Rodriques, M. C.

    2007-01-01

    Planning for sample preservation and curation was part of mission design from the beginning. One of the scientific objectives for Genesis included collecting samples of three regimes of the solar wind in addition to collecting bulk solar wind during the mission. Collectors were fabricated in different thicknesses for each regime of the solar wind and attached to separate frames exposed to the solar wind during specific periods of solar activity associated with each regime. The original plan to determine the solar regime sampled for specific collectors was to identify to which frame the collector was attached. However, the collectors were dislodged during the hard landing making identification by frame attachment impossible. Because regimes were also identified by thickness of the collector, the regime sampled is identified by measuring fragment thickness. A variety of collector materials and thin films applied to substrates were selected and qualified for flight. This diversity provided elemental measurement in more than one material, mitigating effects of diffusion rates and/or radiation damage. It also mitigated against different material and substrate strengths resulting in differing effects of the hard landing. For example, silicon crystal substrates broke into smaller fragments than sapphire-based substrates and diamond surfaces were more resilient to flying debris damage than gold. The primary responsibility of the curation team for recovery was process documentation. Contingency planning for the recovery phase expanded this responsibility to include not only equipment to document, but also gather, contain and identify samples from the landing area and the recovered spacecraft. The team developed contingency plans for various scenarios as part of mission planning that included topographic maps to aid in site recovery and identification of different modes of transport and purge capability depending on damage. A clean tent, set-up at Utah Test & Training Range

  19. 78 FR 49507 - Genesis Solar, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Genesis Solar, LLC; Supplemental Notice That Initial Market- Based Rate...-referenced proceeding of Genesis Solar, LLC's application for market-based rate authority, with...

  20. 75 FR 69458 - Notice of Availability of the Record of Decision for the Genesis Solar Energy Project and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-12

    ... Bureau of Land Management Notice of Availability of the Record of Decision for the Genesis Solar Energy... Genesis Solar Energy Project (GSEP). The GSEP is a concentrated solar electrical generating facility using... in the Federal Register on August 27, 2010 (75 FR 52736). Publication of the Notice of...

  1. Decontaminating Solar Wind Samples with the Genesis Ultra-Pure Water Megasonic Wafer Spin Cleaner

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Rodriquez, M. C.; Allton, J. H.; Stansbery, E. K.

    2009-01-01

    The Genesis sample return capsule, though broken during the landing impact, contained most of the shattered ultra-pure solar wind collectors comprised of silicon and other semiconductor wafers materials. Post-flight analysis revealed that all wafer fragments were littered with surface particle contamination from spacecraft debris as well as soil from the impact site. This particulate contamination interferes with some analyses of solar wind. In early 2005, the Genesis science team decided to investigate methods for removing the surface particle contamination prior to solar wind analysis.

  2. What is the role of absorption atelectasis in the genesis of perioperative pulmonary collapse?

    PubMed

    Joyce, C J; Baker, A B

    1995-12-01

    During anaesthesia the combination of breathing at low lung volume, the administration of nitrous oxide and high inspired oxygen concentrations produces conditions that favour absorption atelectasis. Measures such as adding nitrogen to the inspired mixture and avoiding high inspired oxygen concentrations would reduce the amount of perioperative atelectasis if gas absorption was important in the genesis of perioperative pulmonary collapse. Experimental results demonstrate that these measures do not protect against atelectasis. This indicates that absorption atelectasis does not play a significant role in the genesis of perioperative pulmonary collapse. Compression atelectasis may be the underlying mechanism. PMID:8669602

  3. Mineralogy of Apollo 15415 ?genesis rock' - Source of anorthosite on moon.

    NASA Technical Reports Server (NTRS)

    Steele, I. M.; Smith, J. V.

    1971-01-01

    Results of electron microprobe analyses of plagioclase points and pyroxene grains of Apollo 15415 ?genesis rock.' It is pointed out that no evidence of cumulate textures has yet appeared to support suggestions of extensive crystal-liquid differentiation producing an anorthositic crust or a lunar crust composed of a mixture of plagioclase-rich rock, basalts and minor ultramafic material, which require that plagioclase crystals float in a basaltic liquid. The plagioclase in 15415 does not show cumulate texture either. It is noted that it remains to be seen whether rock 15415 is correctly named the ?genesis rock.'

  4. Time and metamorphic petrology: Calcite to aragonite experiments

    USGS Publications Warehouse

    Hacker, B.R.; Kirby, S.H.; Bohlen, S.R.

    1992-01-01

    Although the equilibrium phase relations of many mineral systems are generally well established, the rates of transformations, particularly in polycrystalline rocks, are not. The results of experiments on the calcite to aragonite transformation in polycrystalline marble are different from those for earlier experiments on powdered and single-crystal calcite. The transformation in the polycrystalline samples occurs by different mechanisms, with a different temperature dependence, and at a markedly slower rate. This work demonstrates the importance of kinetic studies on fully dense polycrystalline aggregates for understanding mineralogic phase changes in nature. Extrapolation of these results to geological time scales suggests that transformation of calcite to aragonite does not occur in the absence of volatiles at temperatures below 200??C. Kinetic hindrance is likely to extend to higher temperatures in more complex transformations.

  5. UHP metamorphism in Greece: Petrologic data from the Rhodope Mountains

    NASA Astrophysics Data System (ADS)

    Baziotis, I. P.; Mposkos, E.; Krohe, A.; Wawrzenitz, N. H.; Liu, Y.; Taylor, L. A.

    2012-12-01

    Metamorphic rocks contain invaluable information for understanding the orogenic mechanisms of a tectonic regime. It is now well recorded and recognized that subduction of oceanic lithosphere and collision of continental blocks can result in sinking of subducted rocks to deeper levels than normal (>100 km). Further, the discovery of coesite and diamond in apparently regionally metamorphosed rocks provoked issues, for returning these rocks to the surface relatively fast, thereby preserving the UHP conditions. These UHPM terrains have been identified in more than twenty provinces worldwide. In Greece, UHPM rocks occur in the Rhodope area, one of the major tectono-metamorphic units located in NE Greece. This region consists of different metamorphic complexes involved in the Alpine collisional history between the Eurasian and African plates (e.g., Krohe & Mposkos, 2002-Geol Soc London Spec Pub, 204, 151). In Rhodope, a Jurassic UHP metamorphism is confirmed in the uppermost Kimi and the underlying Sidironero complexes (Mposkos & Kostopoulos, 2001- EPSL, 192, 497; Perraki et al., 2004-5th ISEMG, T2-35, 2006- EPSL, 241, 672; Liati, 2005- Con Min Pet, 150, 608; Bauer et al., 2007- Lithos, 99, 207). UHP metamorphism is evidenced by the presence of octahedral microdiamond inclusions (3 to 10 μm) in protective garnets, within the metapelitic gneisses. Microdiamonds probably formed from a supercritical fluid under extreme P-T conditions. The latter is strengthened by the presence of composite inclusions consisting of CO2, calcite, and microdiamonds. Other UHP indicators include: 1) quartz rods and rutile needle exsolutions in metapelitic garnet, suggesting a former titaniferous super-silicic (majoritic) garnet formed at P >4GPa; 2) oriented quartz lamellae in eclogitic clinopyroxene having been exsolved from a former super-silicic UHP precursor; and 3) coesite pseudomorphs in garnet, where radial cracks around multi-crystalline-quartz aggregates are indicative of the former

  6. Minerologic and Petrologic Studies of Meteorites and Lunar Samples

    NASA Technical Reports Server (NTRS)

    Wood, John

    2000-01-01

    In the past year this group continued essentially full time research on extraterrestrial materials, and the question of the origin of the solar system. The continuing scientific staff consists of the P.I. and Visiting Scientist Michael Petaev. Vitae for Wood and Petaev appear in Sec. 6. We benefit from the part time services of a Project Administrator (Judith Terry) and a Secretary (Muazzez Lohmiller). In January 1999 the P.I. assumed the Chairmanship of COMPLEX, the Committee on Planetary and Lunar Exploration of the Space Studies Board, National Research Council. Wood and Petaev were authors or coauthors of 21 publications, new manuscripts, and abstracts in the last year. These are listed above, and referenced by number [n] in the discussion below. Other references to the literature made in this Section are listed in Sec. 3.

  7. Polytopic vector analysis in igneous petrology: Application to lunar petrogenesis

    NASA Astrophysics Data System (ADS)

    Shervais, John W.; Ehrlich, R.

    1993-05-01

    Lunar samples represent a heterogeneous assemblage of rocks with complex inter-relationships that are difficult to decipher using standard petrogenetic approaches. These inter-relationships reflect several distinct petrogenetic trends as well as thermomechanical mixing of distinct components. Additional complications arise from the unequal quality of chemical analyses and from the fact that many samples (e.g., breccia clasts) are too small to be representative of the system from which they derived. Polytopic vector analysis (PVA) is a multi-variate procedure used as a tool for exploratory data analysis. PVA allows the analyst to classify samples and clarifies relationships among heterogenous samples with complex petrogenetic histories. It differs from orthogonal factor analysis in that it uses non-orthogonal multivariate sample vectors to extract sample endmember compositions. The output from a Q-mode (sample based) factor analysis is the initial step in PVA. The Q-mode analysis, using criteria established by Miesch and Klovan and Miesch, is used to determine the number of endmembers in the data system. The second step involves determination of endmembers and mixing proportions with all output expressed in the same geochemical variable as the input. The composition of endmembers is derived by analysis of the variability of the data set. Endmembers need not be present in the data set, nor is it necessary for their composition to be known a priori. A set of any endmembers defines a 'polytope' or classification figure (triangle for a three component system, tetrahedron for a four component system, a 'five-tope' in four dimensions for five component system, et cetera).

  8. Polytopic vector analysis in igneous petrology: Application to lunar petrogenesis

    NASA Technical Reports Server (NTRS)

    Shervais, John W.; Ehrlich, R.

    1993-01-01

    Lunar samples represent a heterogeneous assemblage of rocks with complex inter-relationships that are difficult to decipher using standard petrogenetic approaches. These inter-relationships reflect several distinct petrogenetic trends as well as thermomechanical mixing of distinct components. Additional complications arise from the unequal quality of chemical analyses and from the fact that many samples (e.g., breccia clasts) are too small to be representative of the system from which they derived. Polytopic vector analysis (PVA) is a multi-variate procedure used as a tool for exploratory data analysis. PVA allows the analyst to classify samples and clarifies relationships among heterogenous samples with complex petrogenetic histories. It differs from orthogonal factor analysis in that it uses non-orthogonal multivariate sample vectors to extract sample endmember compositions. The output from a Q-mode (sample based) factor analysis is the initial step in PVA. The Q-mode analysis, using criteria established by Miesch and Klovan and Miesch, is used to determine the number of endmembers in the data system. The second step involves determination of endmembers and mixing proportions with all output expressed in the same geochemical variable as the input. The composition of endmembers is derived by analysis of the variability of the data set. Endmembers need not be present in the data set, nor is it necessary for their composition to be known a priori. A set of any endmembers defines a 'polytope' or classification figure (triangle for a three component system, tetrahedron for a four component system, a 'five-tope' in four dimensions for five component system, et cetera).

  9. Petrology of Aztec Wash pluton, Eldorado Mountains, southern Nevada

    SciTech Connect

    Falkner, C.M.; Miller, C.F. ); Wooden, J.L. )

    1993-04-01

    Aztec Wash pluton, a 50 km[sup 2] intrusive complex in the northern Eldorado Mountains, was emplaced ca. 16 Ma (Faulds et al., 1990) during extension within the Colorado River Corridor. The pluton displays extreme compositional variability, ranging from olivine gabbro (ca. 50 wt% SiO[sub 2]) to highly evolved aplite (76% SiO[sub 2]). Most of the intrusion is medium grained, homogeneous granite (ca. 72% SiO[sub 2]), but 1/3 is highly heterogeneous and dominated by mafic to intermediate rocks; a 6 [times] 3km, N-S mafic zone almost bisects the pluton. Well-displayed magma mingling and late mafic and felsic dikes verify the coexistence of mafic and felsic melts. Hornblende barometry indicates that the entire exposed portion of Aztec Wash pluton was emplaced at very shallow depth (complex pre-pluton deformational history. The authors propose the following emplacement history for Aztec Wash pluton: felsic magma intruded shallow levels of crust; the base of the magma chamber was intruded by basalt; after the upper portion of the initial magma was largely crystallized, basalt ascended into, perhaps remobilized, and mingled with felsic magma; this ascent may have been facilitated by E-W extension of the crystallizing pluton; more discrete syn- to post-pluton, mafic to felsic dikes mark additional intrusive pulses triggered by basalt intrusion and extensional fracturing. Field relations suggest that the mingling led to mixing in both the main units and the late dikes, but geochemical data indicate that mixing, if it occurred, was not a simple 2-end member process.

  10. [Complex decongestive therapy].

    PubMed

    Heinig, B; Wollina, U

    2015-11-01

    The amount of physical pressure plays an important role in complex decongestive therapy (CDT). As a function of pressure, microcirculation takes place between blood vessels and tissue. As part of the total lymphatic system, lymphatic vessels transport the lymphatic load from the interstitial space to the blood stream. The lymphatic vessel system, characterized by specific anatomical conditions like initial lymphatic vessels, precollectors, collectors, and lymphatic strains, is the therapeutic target of complex decongestive therapy. Components of CDT include manual lymphatic drainage, compression therapy, decongestive kinesitherapy, and good skin care, which increase the transport capacity of the lymphatic vessel system. Currently, CDT is acknowledged as the main conservative treatment of lymphedema of primary and secondary genesis, lipolymphedema, and phlebolymphedema. In clinical practice, we are increasingly confronted with edema of multifactorial genesis requiring a critical discussion and stocktaking of comprehensive clinical findings in terms of the indication for CDT. Therapeutic success depends on a joint application of all CDT components and patient compliance. To an increasing extent, medical research tries to combine successfully CDT with adjunct treatment options. PMID:26315101

  11. Petrology and reservoir paragenesis in the Sussex 'B' sandstone of the upper Cretaceous Cody Shale, House Creek and Porcupine Fields, Powder River Basin, Wyoming

    SciTech Connect

    Higley, D.K.

    1991-05-03

    Using petrologic and sedimentologic studies, the paper characterizes the influence of sedimentologic and petrologic variations on reservoir heterogeneity in the Sussex 'B' sandstone in the House Creek and Porcupine fields, Powder River Basin, Wyoming. Effects of authigenic minerals on reservoir properties are described in detail for selected inter-ridge and ridge facies sandstones.

  12. Accretion, metamorphism, and brecciation of ordinary chondrites - Evidence from petrologic studies of meteorites from Roosevelt County, New Mexico

    NASA Technical Reports Server (NTRS)

    Scott, Edward R. D.; Taylor, G. Jeffrey; Keil, Klaus

    1986-01-01

    The olivines and pyroxenes from twenty-nine ordinary chondrites from Roosevelt County, New Mexico are examined. The mineralogical properties of the chondrites studied are described. Correlations between mineral compositions and petrologic type and between petrologic type and bulk chemistry are analyzed. It is observed that mean CaO concentrations in olivine show significant variations among equilibrated chondrites, but these are not correlated with petrologic type; the degree of heterogeneity of FeO concentrations in olivines of types 4-6 is not correlated with the degree of metamorphism; and mean FeO concentrations of silicates show average increases of 3-5 percent from type 4 to type 6 in each group.

  13. Magma plumbing system of the Aso-3 large pyroclastic eruption cycle at Aso volcano, Southwest Japan: Petrological constraint on the formation of a compositionally stratified magma chamber

    NASA Astrophysics Data System (ADS)

    Kaneko, Katsuya; Inoue, Kazuhisa; Koyaguchi, Takehiro; Yoshikawa, Masako; Shibata, Tomoyuki; Takahashi, Toshiro; Furukawa, Kuniyuki

    2015-09-01

    Aso volcano has the largest caldera (18 × 25 km in diameter) in the southwestern Japan Island Arc, and it formed as the result of four large (VEI = 6-7) pyroclastic-eruption cycles. We study the penultimate large eruption cycle, the Aso-3 cycle, which occurred 123 ka with an ejecta volume of more than 150 km3. The processes in the pre-eruptive magma chamber and the magma genesis of the Aso-3 cycle were inferred from geological data, phenocryst chemistry, and whole-rock chemical and Sr-, Nd-, and Pb isotopic analyses of juvenile clasts. The geological and petrological data indicate that the pre-eruptive magma chamber was stratified compositionally into three layers: from top to bottom, silicic, intermediate, and mafic magma layers. The three magma layers had a uniform isotope composition, suggesting that all the magmas were generated from a single source. The silicic and intermediate magmas were not generated from the mafic magma by fractional crystallization. The silicic magma has higher Ni content (compatible element) than the mafic magma. This suggests that these magmas were produced by partial melting of the same mafic crust but with differing amounts of partial melting: the silicic magma was produced by a low degree of partial melting of the source rock without fractional crystallization, and the mafic magma was produced by a large degree of partial melting followed by fractional crystallization. The intermediate magma compositions plot on the tie line between the silicic magma and the melt of the mafic magma in variation diagrams, and the intermediate magma has phenocrysts whose compositions are identical with those in the silicic magma. This observation indicates that, before the Aso-3 eruption cycle, a two-layer stratified magma chamber of the silicic and mafic magmas was formed as a result of melting of the mafic crust, which was followed by formation of the intermediate layer as a result of interfacial mixing between the silicic magma and the melt of

  14. Geochemistry and genesis of behind-arc basaltic lavas from eastern Nicaragua

    NASA Astrophysics Data System (ADS)

    Janoušek, V.; Erban, V.; Holub, F. V.; Magna, T.; Bellon, H.; Mlčoch, B.; Wiechert, U.; Rapprich, V.

    2010-05-01

    The petrology and chemistry of the Behind the Volcanic Front (BVF) lavas from eastern mainland Nicaragua and the adjacent Great Corn Island in the Caribbean Sea illustrate the complex nature of sources and processes operating in such a tectonic setting. The older, Early Miocene (˜ 17 Ma) group of low-Ti (< 1 wt.%) basalts-andesites is characterized by a strong LILE/HFSE depletion. The low-Ti lavas from El Rama and El Bluff areas are interpreted as relics of Early Miocene volcanic arc, largely analogous to the nowadays extinct Coyol arc further west. However, these rocks differ in some parameters from the modern volcanic front lavas, most notably in having lower δ7Li values, Ba/Yb ratios and lower U contents. The younger high-Ti (Ti > 1.5%) lavas, rich in other HFSE as well, are represented both by alkaline (Quaternary trachybasalts: Volcán Azul and Kukra Hill) and subalkaline (basalts-basaltic andesites: Late Miocene, ˜ 11 Ma Great Corn Island and Quaternary, Pearl Lagoon) volcanic rocks. The Late Miocene and Quaternary high-Ti BVF lavas probably represent small-volume decompression melts of a source similar to that of the OIB-like magmas, most likely upwelling asthenosphere having a strong Galápagos mantle imprint. The positive Sr-Nd isotopic correlation indicates an interaction between this OIB component and a depleted lithospheric mantle modified by a subduction-related influx of Sr and, to a lesser extent, other hydrous fluid-mobile elements. However, the rocks show no recognizable influence of the modern subduction. The feeble trace-element (e.g., slightly elevated Ba, K, and Sr at some localities) and a more pronounced Sr-Li isotopic subduction-related signal stems most likely from the Miocene convergence episode. Subduction of the Galápagos hot-spot tracks in Costa Rica produces magmas that can be readily recognized by their elevated Sr isotopic ratios due to seafloor alteration; the Nd isotopic signature remains unaffected. Such a component with

  15. Blending Curriculum with Research in an Undergraduate Petrology Course: A Recipe for Success?

    NASA Astrophysics Data System (ADS)

    Gonzales, D. A.; Semken, S. C.

    2009-12-01

    In this presentation we discuss the design, key curricular elements, and strengths and weaknesses of an undergraduate course in the Department of Geosciences at Fort Lewis College that was recast to focus on petrologic studies in the Southern Rocky Mountains and Colorado Plateau. Redesign of the course retained an additional petrology option in the curriculum and offered undergraduates a richer opportunity to learn and practice science-research skills. This course emphasizes direct engagement and student responsibility for learning: traits valuable in transforming undergraduates into experienced and competent professionals. Previous offerings of this course have been field based, each having a unique context for research. The primary pedagogical strategy was to blend field studies with inquiry to promote authentic, student-driven research. Students applied and tested their prior knowledge, and used observational and interpretative skills, to investigate major regional rock bodies and geologic histories, as opposed to completing a set of activities with predefined outcomes. In 2010, students will work on an NSF-funded project to test hypotheses on the origin and evolution of mafic magmas of the Navajo volcanic field. This research will most involve petrographic and microanalytical techniques on rock specimens with a subordinate amount of field work. Formative and summative assessment data for previous offerings of this course reveal that these classes have an impact on the academic interests and future successes of students. Assessment data collected from students, and other faculty that interacted with them, indicate that students in this research-oriented petrology course have gained a greater understanding of the elements and complications of research. They have also developed geologic skills and a passion for geologic research that have influenced subsequent academic (and later career) paths of the students.

  16. Diffusion Modelling as a Useful Petrological Tool for Near-Real-Time Volcanic Eruption Monitoring

    NASA Astrophysics Data System (ADS)

    Couperthwaite, F.; Morgan, D. J.; Thordarson, T.; Shea, T.; Harvey, J.; Trusdell, F.; Pankhurst, M. J.

    2015-12-01

    Diffusion modelling is a well-established petrological technique for investigating the timescales of sub-surface processes occurring within magma storage bodies and transport systems prior to eruption. The technique typically produces - at best - results some weeks after a volcanic eruption has commenced. This contribution describes progress made on a user-friendly, easy-to-use petrological 'tool' that can be deployed in near-real time at the onset of and during an eruption. This is important for fast timescale retrieval (within days rather than weeks) without compromising the reliability of the timescale retrieved. This has implications for eruption monitoring and hazard mitigation, providing a petrological time-series complementing existing geophysical monitoring techniques. Current methods are constrained by data processing rates and the geometrical corrections required to control for random sectioning, crystal shape uncertainties and mineral anisotropy. Using a set of Piton de la Fournaise (Réunion Island) lava flow samples and a suite of Mauna Loa (HI, US) air fall and lava flow samples, magmatic timescales for Mg-Fe diffusion in olivine have been retrieved. Piton has a monodisperse crystal population, making a near-perfect baseline from which to pick apart the current diffusion modelling method. In so doing, a greater understanding of the sources of scatter and uncertainty in the process of timescale retrieval was obtained. The variety of potential sectioning orientations and their interaction with diffusion processes led to the proposal by Shea et al, 2015, in press, of selection rules to select boundaries, based on numerical models. Combined with evaluations of crystal shape, crystal axial ratios, interfacial angles, U-stage measurements and a statistical approach, such selection rules should allow the orientation of the grain within a sample to be inferred, negating the need for independent EBSD measurements and enabling a faster processing technique.

  17. Petrology of the Plutonic Rocks of west-central Alaska

    USGS Publications Warehouse

    Miller, Thomas P.

    1970-01-01

    A series of plutons in west-central Alaska defines the Hogatza plutonic belt which extends for about 200 miles in an east-west direction from the northeastern Seward Peninsula to the Koyukuk River. The plutonic rocks have an aggregate area of about 1,200 square miles and their composition, distribution, and possible petrogenesis are discussed for the first time in this report. Field, petrographic and chemical data supported by K/Ar age dating indicate the plutonic rocks are divisible into two suites differing in age, location, and composition. The western plutons are mid-Cretaceous (~100 m.y.) in age and consist of a heterogeneous assemblage of monzonite, syenite, quartz monzonite. Associated with these granitic rocks is a group of alkaline sub-silicic rocks that forma belt of intrusive complexes extending for a distance of at least 180 miles from west-central Alaska to the Bering Sea. The complex at Granite Mountain shows a rare example of zoning from an alkaline rim to a quartz-bearing core. The occurrence of a similar complex at Cape Dezhnev on the easternmost tip of Siberia suggests the alkaline province may extend into Siberia. The easternmost plutons are Late Cretaceous (180 m.y.) in age and composed primarily of granodiorite and quartz monzonite similar to calc-alkaline plutons found throughout the North America Cordillera. The plutons are epizonal and intrude deformed but unmetamorphosed Lower Cretaceous andesitic volcanics and volcanic graywacke which constitute the highly mobile Yukon-Koyukuk volcanogenic province of west-central Alaska. No older rocks have been found within the confines of this vast tract; the occurrence of a bounding ophiolite sequence has lead to the suggestion that the province was formed by large-scale rifting and is underlain by oceanic crust. The possibility of no juvenile sialic crust over much of the area suggests that the potassium-rich magma now represented by the alkaline rocks originated in the mantle. The distribution of the

  18. The added value of biomarker analysis to the genesis of Plaggic Anthrosols.

    NASA Astrophysics Data System (ADS)

    van Mourik, Jan; Jansen, Boris

    2015-04-01

    Coversands (chemical poor Late-glacial aeolian sand deposits) dominate the surface geology of an extensive area in northwestern Europe. Plaggic Anthrosols occur in cultural landscapes, developed on coversands. They are the characteristic soils that developed on ancient fertilized arable fields. Plaggic Anthrosols have a complex genesis. They are records of aspects environmental and agricultural history. In previous studies information of the soil records was unlocked by application of pollen analysis, 14C and OSL dating. In this study we applied biomarker analysis to unlock additional information about the applied organic sources in the production of plaggic manure. Radiocarbon dating suggested the start of sedentary agriculture (after a period, characterized by shifting cultivation and Celtic fields) between 3000 and 2000 BP. In previous studies is assumed that farmers applied organic sods, dug on forest soils and heath to produce organic stable manure to fertilize the fields. The mineral fraction of the sods was supposed to be responsible for the development of the plaggic horizon and the raise of the land surface. Optically stimulated Luminescence dating however suggested that plaggic deposition on the fields started relatively late, in the 18th century. The use of ectorganic matter from the forest soils must have been ended in the 10th-12th century, due to commercial forest clear cuttings as recorded in archived documents. These deforestations resulted in the first extension of sand drifting and famers had to protect the valuable heath against this ' environmental catastrophe' . The use of heath for sheep grazing and other purposes as honey production could continue till the 18th century, as recorded in archived documents. In the course of the 18th century, the population growth resulted in increasing demand for food. The deep stable economy was introduced and the booming demand for manure resulted in intensive sod digging on the heath. This caused heath

  19. Petrology and petrogenesis of the Eocene Volcanic rocks in Yildizeli area (Sivas), Central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Doğa Topbay, C.; Karacık, Zekiye; Genç, S. Can; Göçmengil, Gönenç

    2015-04-01

    Yıldızeli region to the south of İzmir Ankara Erzincan suture zone is situated on the large Sivas Tertiary sedimentary basin. After the northern branch of the Neotethyan Ocean was northerly consumed beneath the Sakarya Continent, a continent - continent collision occurred between the Anatolide- Tauride platform and Pontides and followed a severe intermediate magmatism during the Late Cretaceous- Tertiary period. This created an east-west trending volcanic belt along the whole Pontide range. In the previous studies different models are suggested for the Eocene volcanic succession such as post-collisional, delamination and slab-breakoff models as well as the arc model for its westernmost parts. We will present our field and geochemical data obtained from the Yıldızeli and its surroundings for its petrogenesis, and will discuss the tectonic model(s) on the basis of their geochemical/petrological aspects. Cenozoic volcanic sequences of Yıldızeli region which is the main subject of this study, overlie Pre-Mesozoic crustal meta-sedimentary group of Kırşehir Massif, Ophiolitic mélange and Cretaceous- Paleocene? flysch-like sequences. In the northern part of Yıldızeli region, north vergent thrust fault trending E-W seperates the ophiolitic mélange complex from the Upper Cretaceous-Paleocene and Tertiary formations. Volcano-sedimentary units, Eocene in age, of the Yıldızeli (Sivas-Turkey) which are intercalated with sedimentary deposits related to the collision of Anatolide-Tauride and a simultaneous volcanic activity (i.e. the Yıldızeli volcanics), exposed throughout a wide zone along E-W orientation. Yıldızeli volcanics consist of basalts, basaltic-andesites and andesitic lavas intercalated flow breccias and epiclastic, pyroclastic deposits. Basaltic andesite lavas contain Ca-rich plagioclase + clinopyroxene ± olivine with minor amounts of opaque minerals in a matrix comprised of microlites and glass; andesitic lavas are generally contain Ca

  20. Sphene-centered ocellar texture as a petrological tool to unveil the mechanism facilitating magma mixing

    NASA Astrophysics Data System (ADS)

    Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor

    2015-04-01

    The sphene-centered ocellar texture is a unique magma mixing feature characterized by leucocratic ocelli of sphene enclosed in a biotite/hornblende-rich matrix (Hibbard, 1991). The ocelli usually consist of plagioclase, K-feldspar and quartz with sphene crystals at its centre. Although geochemical and isotopic data provide concrete evidence for the interaction between two compositionally distinct magmas, the exact processes by which mixing takes place is yet uncertain. So, textural analysis can be used to decipher the behaviour of two disparate magmas during mixing. Presented work is being carried out on the sphene ocelli, occurring in hybrid rocks of the Nimchak Granite Pluton (NGP), to understand its formation while two compositionally different magmas come in contact and try to equilibrate. The NGP is ca. 1 km2in extent which has been extensively intruded by number of mafic dykes exhibiting well preserved magma mixing and mingling structures and textures in the Bathani Volcano-Sedimentary Sequence (BVSS) located on the northern fringe of the Proterozoic Chotanagpur Granite Gneiss Complex (CGGC) of eastern Indian Shield. From petrographic and mineral chemical studies we infer that when basaltic magma intruded the crystallizing granite magma chamber, initially the two compositionally different magmas existed as separate entities. The first interaction that took place between the two phases is diffusion of heat from the relatively hotter mafic magma to the colder felsic one followed by diffusion of elemental components like K and incompatible elements from the felsic to the mafic domain. Once thermal equilibrium was attained between the mafic and felsic melts, the rheological contrasts between the two phases were greatly reduced. This allowed the felsic magma to back-vein into the mafic magma. The influx of back-veined felsic melt into the mafic system disrupted the equilibrium conditions in the mafic domain wherein minerals like amphibole, plagioclase and biotite

  1. Mercury: Informing Remote Sensing through Petrology in the Absence of Samples from the Innermost Planet

    NASA Astrophysics Data System (ADS)

    McCoy, T. J.; Nittler, L. R.; Stockstill-Cahill, K.; Blewett, D. T.

    2012-12-01

    Remote sensing missions and petrologic studies are complementary methods of understanding airless planetary bodies. For bodies with both orbital missions and samples available for laboratory study, missions provide global chemical, mineralogical, and geologic data sets and context for samples, whereas samples often provide complementary petrogenetic histories in a chronological framework. In contrast, although the wealth of orbital data from MESSENGER is not complemented by samples from Mercury, petrologic and experimental studies remain essential to understanding the innermost planet. Prior to MESSENGER, most models centered on high-temperature events and formation under highly reducing conditions to explain Mercury's high metal to silicate ratio. These models predicted enrichment in refractory elements and depletion in volatile elements. The inference of formation at highly reducing conditions is supported by MESSENGER results. The low FeO concentration in the crust, implied low FeO contents of the mantle, apparent efficient partitioning of iron into the core, and evidence for Ca- and/or Mg-sulfides from X-Ray Spectrometer data are all consistent with reducing conditions. In contrast, the suggestion that Mercury is highly volatile-depleted has been refuted. Direct evidence for a relatively volatile-rich planet come from Na, K, and S abundances measured on the surface with MESSENGER's XRS and Gamma-Ray Spectrometer and the presence of neutral and ionized Na, K, and S species in the exosphere. Indirect evidence for volatile-rich compositions include the suggestion of volcanic vents with associated mantling pyroclastic deposits, hollows inferred to form by geologically recent volatile loss, and an inferred interior structure that includes a solid iron sulfide layer at the top of Mercury's fluid core. Petrologic and experimental studies of meteorites have played a key role in deciphering orbital data from MESSENGER. Partial melts from an enstatite chondrite

  2. Geochemical work of the Geochemistry and Petrology Branch U.S. Geological Survey

    USGS Publications Warehouse

    Ingerson, E.

    1954-01-01

    The current geochemical work of the Geochemistry and Petrology Branch of the U.S. Geological Survey is outlined under the headings of geochemical compilations, laboratory projects, and field-laboratory projects. Some thirty-seven active projects are described. Six others are mentioned which are planned for the near future. The importance and value of cooperative projects and the "team approach" are emphasized. The hope is expressed that more such projects can be undertaken; also, that summaries of geochemical work under way elsewhere will be published soon for the advancement and better coordination of geochemical research. ?? 1954.

  3. "MERAPIDATA": New Petrologic and Geochemical Database of the Merapi Volcano, Central Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Borisova, A. Y.; Martel, C.; Pratomo, I.; Toutain, J.; Sumarti, S.; Surono, S.

    2011-12-01

    Petrologic and geochemical databases of erupted products are critical for monitoring and predicting the evolution of active volcanoes. To monitor the activity of one of the most dangerous volcanoes in the world, Merapi Volcano in Indonesia, in the framework of the new instrumental site VELI (Volcans Explosifs - Laboratoires Indonésiens labelled by INSU in 2009 in France), we generated "MERAPIDATA", a complete database of available petrologic and geochemical data published in the literature on pyroclastic flows, tephra, lavas and xenoliths coupled with the exact ages of historical flows [1] or estimated ages based on 14C geochronology [2]. "MERAPIDATA" permits to access complete petrologic, geochemical, and geochronological information (e.g., major, trace element and Sr-Nd-Pb-O isotopic composition of the bulk volcanic rocks, xenoliths, minerals and glasses; textural information; type of eruption; classification) of a given volcanic product or series. In addition to ~300 published volcanic products, new data on 2 pyroclastic flows, 1 tephra and 4 ash samples collected on northern and western slopes of the volcano in October and November 2010 during subplinian type eruption have been added to "MERAPIDATA". The 2010 ash sample chemistry allows classifying them as high-K basaltic andesite. The ash samples demonstrate major and trace element compositions typical for the high-K series. For the first time, we obtained complete data on the Merapi ash samples which characterized by low L.O.I. ≤ 0.58 wt%, CO2total ≤ 0.05 wt%, H2Ototal = 0.3 - 0.5 wt%, Stotal ≤ 0.13 wt% and moderate Cl (550 - 1120 ppm) contents. The ash-leachates produced by leaching experiments demonstrate constant F/Cl ratios (0.05 ± 0.01) and Ca-Na-K enrichment (Ca/Na= 3 - 7, Na/K = 1 - 5). Sr-Nd-Pb-O isotopic analyses on the 2010 Merapi products are in progress. New petrologic (e.g., melt and fluid inclusion data, T - P - fO2 - aH2O - aCO2) and geochemical (e.g., volatile, major, trace element and

  4. Global petrologic variations of the Moon: A ternary-diagram approach

    NASA Technical Reports Server (NTRS)

    Davis, Philip A.; Spudis, Paul D.

    1987-01-01

    A ternary-diagram approach is used to show on a single map as much detailed geochemical information concerning petrologic variations within the lunar crust as is possible. The classification map shows the global spatial distributions of end-member compositions, the transitional spatial relations between end-member compositions, and quantitative estimates of relative proportions of each end member at each pixel location within the orbital groundtracks. The use of elemental ratios in this analysis, instead of the commonly used elemental bivariate diagrams, shows geologic information that is otherwise hidden in individual elemental databases.

  5. Spinel cataclasites in 15445 and 72435 - Petrology and criteria for equilibrium

    NASA Technical Reports Server (NTRS)

    Baker, M. B.; Herzberg, C. T.

    1980-01-01

    The problem of establishing the existence of equilibrium among the coexisting phases in the rock is addressed by presenting petrographic and mineral chemistry data on a new spinel cataclasite from 15445 (clast H) and data more extensive than those previously available on two clasts in 72435. Criteria useful in reconstructing the original petrology of these and other spinel cataclasites are analyzed by considering equilibrium among the different phases, that is, the mono- or polymict nature of these cataclasized samples. Finally, the role of impact processes in disturbing the equilibria is discussed.

  6. Stratigraphy, petrology, and structure of the Pingston terrane, Mount Hayes C-5 and C-6 quadrangles, eastern Alaska Range, Alaska

    NASA Astrophysics Data System (ADS)

    Nokleberg, W. J.; Schwab, C. E.; Miyaoka, R. T.; Buhrmaster, C. L.

    Recent field, petrologic, and structural studies of the Pingston terrane in the Mount Hayes C-5 and C-6 quandrangles reveal that in this area the terrane: (1) has a highly distinctive stratigraphy, age, petrology (relict textures, relict minerals, and metamorphic facies), and structure; and (2) differs markedly from that described in previous studies. These more recent studies indicate that the major rock types, in order of decreasing abundance, are meta-andesite, metadacite and metarhyodacite flows and (or) tuff, metabasalt, metagabbro, metavolcanic graywacke, metagray-wacke, metasiltstone, metaquartzite or metachert, and very sparse marble. The general petrography of the major rock units in the Pingston terrane is given.

  7. Crustal Genesis and Dynamics in the Jurassic Talkeetna Arc

    NASA Astrophysics Data System (ADS)

    Kelemen, P.; Amato, J.; Behn, M.; Blusztajn, J.; Christensen, N.; Clift, P.; Debari, S.; Draut, A.; Greene, A.; Hacker, B.; Hanghoj, K.; Hart, S.; Hirth, G.; Mattinson, J.; Mehl, L.; Pavlis, T.; Rioux, M.; Trop, J.

    2005-12-01

    We summarize studies of the accreted Talkeetna arc section in Alaska, focusing on the role of arc crust in continental genesis and arc geodynamics. The 200 to 175 Ma section extends from residual mantle peridotite to volcanics, including - in order of decreasing depth - a few 100 m of pyroxenite, rare garnet granulites, cumulate gabbronorites, and felsic plutonic rocks. Lack of inheritance in zircon and relatively constant, high Nd and low Sr isotope ratios indicate that to first order the crustal rocks differentiated from a common parental melt composition and that magmas did not incorporate older crustal material. Amphibolite formed from arc lava. Metasediment had pelagic protoliths, except on the Alaska Peninsula. The arc probably formed new crust during extension, rather than intruding older rocks. South to north younging of zircon and hornblende ages indicates that the arc migrated northward, so the entire section is not a single, tilted vertical column though the Chugach region alone could be. Total crustal thickness was 25 to 35 km, with 6 to 8 km of volcanics. Mid to lower crust is mainly cumulate gabbronorite formed at NNO+2. The thickness of lavas/cumulates is consistent with crystal fractionation to form average lavas from the most primitive observed melt compositions. The bulk composition of the crust and the most primitive melts has ~ 49 wt% SiO2, 19 wt% Al2O3, 8 wt% MgO, and Mg# ~ 60. Derivation of these melts from magmas in equilibrium with residual mantle (melt Mg# > 70) requires more than 25% crystal fractionation of cumulates with cpx Mg# between 85 and 93, found only in primitive pyroxenite along the Moho, ~ 1% of the crustal thickness. This discrepancy is likely due to foundering of dense pyroxenites (and garnet granulites) into underlying mantle. Flat REE patterns, low K, low Th/La, and low Mg# at a given SiO2 distinguish Talkeetna most samples from continental crust, which is Th-enriched, LREE enriched, HREE depleted, K-rich, high Mg# andesite

  8. Genesis of ion-adsorption type REE ores in Thailand

    NASA Astrophysics Data System (ADS)

    Sanematsu, K.; Yoshiaki, K.; Watanabe, Y.

    2012-04-01

    Ion-adsorption type REE deposits, which have been economically mined only in southern China, are predominant supply sources for HREE in the world. The ore bodies consist of weathered granites called ion-adsorption ores. The majority of REE (>50 %) are electrostatically adsorbed onto weathering products in the ores and they can be extracted by ion exchange using an electrolyte solution (e.g., ammonium sulfate solution). Recently the occurrences of ion-adsorption ores have been reported in Indochina, SE Asia. In this study, we discuss geochemical and mineralogical characteristics of parent granites and weathered granites in Thailand in order to reveal the genesis of ion-adsorption ores. Permo-Triassic and Cretaceous-Paleogene granite plutons are distributed from northern Thailand to western Indonesia through eastern Myanmar and Peninsular Malaysia. They are mostly ilmenite-series calcalkaline biotite or hornblende-biotite granites. REE contents of the granites range from 60 to 600 ppm and they are relatively high in Peninsula Thailand. REE-bearing minerals consist mainly of apatite, zircon, allanite, titanite, monazite and xenotime. Some I-type granites contain REE fluorocarbonate (probably synchysite-(Ce)) in cavities and cracks in feldspars and it is the dominant source of REE for ion-adsorption ores because the fluorocarbonate is easily soluble during weathering. In contrast, insoluble monazite and xenotime are not preferable for ion-adsorption ores although they are common ore minerals of placer REE deposits. Weathered granites show REE contents ranging from 60 to 1100 ppm in Thailand because REE are relatively immobile compared with mobile elements (e.g., Na, K, Ca). In the weathered granites, REE are contained in residual minerals and secondary minerals and are adsorbed onto the surface of weathering products. A weathering profile of granite with ion-adsorption type mineralization can be divided into upper and lower parts based on REE enrichment and Ce

  9. Weathering and genesis of Soils from Ellsworth Mountains, East Antarctica

    NASA Astrophysics Data System (ADS)

    Karoline Delpupo Souza, Katia; Schaefer, Carlos Ernesto; Michel, Roberto; Monari, Julia; Machado, Vania

    2015-04-01

    Knowledge on Antarctic soils from the Ellsworth Mountains (EM) are patchy comparatively with Dry Valleys soils from the Transantartic Mountains, and could help understand the genesis of cryogenic soils under extreme dry, cold desert conditions. The EM are a slightly arcuate 350-km-long north-northwest-trending mountain chain is bordered on the west by the polar plateau of West Antarctica and on the east by Ronne Ice Shelf. The range is as much as 90 km wide and constitutes one of the largest areas of exposed bedrock in West Antarctica. The stratigraphic succession in the EM includes strata from Cambriam to Permian in age. The objective of this study is to analyze the properties of soils from EM in order to identify the main factors and processes involved in soil formation under cold desert conditions in Antarctica. The sampling design aimed to represent the different geological substrates (marble-clast conglomerate, graywacke, argillite, conglomerate, black shale, marble and quartzite) as well as altitudinal levels and landforms within the same substrate. We characterized soils from EM regarding their morphological, physics and chemical properties. Soil samples were air dried and passed through 2 mm sieves. After removal of water soluble salts, the samples were submitted to chemical and physical analyses such as: pH in water, potential acidity (H + Al), exchangeable bases, total organic carbon, electric conductivity, soil texture and color. The soils classify, for the most part, in weathering stages 1 to 2. Only in the upper parts of ridges were there traces of soils at weathering stage 3. This indicates that much of the present icefree topography has been overridden by ice within the last few hundred thousand years. Cryoturbation is a widespread phenomenon in this area resulting in intense cryoclastic weathering and patterned ground, forming sorted circles, stripes and gelifluxion lobes. The soil show low horizontation, discrete patches of salt on the surface, and

  10. Lava flow rheology: A comparison of morphological and petrological methods

    NASA Astrophysics Data System (ADS)

    Chevrel, M. O.; Platz, T.; Hauber, E.; Baratoux, D.; Lavallée, Y.; Dingwell, D. B.

    2013-12-01

    In planetary sciences, the emplacement of lava flows is commonly modelled using a single rheological parameter (apparent viscosity or apparent yield strength) calculated from morphological dimensions using Jeffreys' and Hulme's equations. The rheological parameter is then typically further interpreted in terms of the nature and chemical composition of the lava (e.g., mafic or felsic). Without the possibility of direct sampling of the erupted material, the validity of this approach has remained largely untested. In modern volcanology, the complex rheological behaviour of lavas is measured and modelled as a function of chemical composition of the liquid phase, fractions of crystals and bubbles, temperature and strain rate. Here, we test the planetary approach using a terrestrial basaltic lava flow from the Western Volcanic Zone in Iceland. The geometric parameters required to employ Jeffreys' and Hulme's equations are accurately estimated from high-resolution HRSC-AX Digital Elevation Models. Samples collected along the lava flow are used to constrain a detailed model of the transient rheology as a function of cooling, crystallisation, and compositional evolution of the residual melt during emplacement. We observe that the viscosity derived from the morphology corresponds to the value estimated when significant crystallisation inhibits viscous deformation, causing the flow to halt. As a consequence, the inferred viscosity is highly dependent on the details of the crystallisation sequence and crystal shapes, and as such, is neither uniquely nor simply related to the bulk chemical composition of the erupted material. This conclusion, drawn for a mafic lava flow where crystallisation is the primary process responsible for the increase of the viscosity during emplacement, should apply to most of martian, lunar, or mercurian volcanic landforms, which are dominated by basaltic compositions. However, it may not apply to felsic lavas where vitrification resulting from

  11. Analyzing the influences of two types of El Niño on Tropical Cyclone Genesis with a modified genesis potential index

    NASA Astrophysics Data System (ADS)

    Yang, Yuxing; Yang, Lei; Wang, Faming

    2016-05-01

    To understand the impacts of large-scale circulation during the evolution of El Niño cycle on tropical cyclones (TC) is important and useful for TC forecast. Based on best-track data from the Joint Typhoon Warning Center and reanalysis data from National Centers for Environmental Prediction for the period 1975-2014, we investigated the influences of two types of El Niño, the eastern Pacific El Niño (EP-El Niño) and central Pacific El Niño (CP-El Niño), on global TC genesis. We also examined how various environmental factors contribute to these influences using a modified genesis potential index (MGPI). The composites reproduced for two types of El Niño, from their developing to decaying phases, were able to qualitatively replicate observed cyclogenesis in several basins except for the Arabian Sea. Certain factors of MGPI with more influence than others in various regions are identified. Over the western North Pacific, five variables were all important in the two El Niño types during developing summer (July-August-September) and fall (October-November-December), and decaying spring (April-May-June) and summer. In the eastern Pacific, vertical shear and relative vorticity are the crucial factors for the two types of El Niño during developing and decaying summers. In the Atlantic, vertical shear, potential intensity and relative humidity are important for the opposite variation of EP- and CP-El Niños during decaying summers. In the Southern Hemisphere, the five variables have varying contributions to TC genesis variation during peak season (January-February-March) for the two types of El Niño. In the Bay of Bengal, relative vorticity, humidity and omega may be responsible for clearly reduced TC genesis during developing fall for the two types and slightly suppressed TC cyclogenesis during EP-El Niño decaying spring. In the Arabian Sea, the EP-El Niño generates a slightly positive anomaly of TC genesis during developing falls and decaying springs, but the

  12. Depth variation of seismic anisotropy and petrology in central European lithosphere: A tectonothermal synthesis from spinel lherzolite

    NASA Astrophysics Data System (ADS)

    Christensen, N. I.; Medaris, L. G., Jr.; Wang, H. F.; Jelínek, E.

    2001-01-01

    Spinel lherzolite xenoliths from the Neogene Kozákov volcano in central Europe, yielding temperatures from 680°C to 1065°C and estimated to originate from depths of 32 to 70 km, provide an exceptionally continuous record of the depth variation in seismic and petrological properties of subcontinental lithospheric mantle. Extraction depths of the xenoliths and thermal history and rheological properties of the mantle have been evaluated from a tectonothermal model for basaltic underplating associated with Neogene rifting. The chemical depletion of sub-Kozákov mantle decreases with depth, the Mg number in olivine decreasing from ˜91.4 to 90.5 and the Cr number in spinel, decreasing from ˜38.9 to 14.7. Texturally, the sampled mantle consists of an equigranular upper layer (32-43 km), an intermediate protogranular layer (43-67 km), and a lower equigranular layer (below 67 km). Olivine petrofabrics show strong axis concentrations, which change with depth from orthorhombic symmetry in the equigranular upper layer to axial symmetry in the lowermost layer. Calculated compressional and shear wave anisotropies, which average 8% and 6%, respectively, show significant depth trends that correlate with variations in depth of olivine fabric strengths and symmetries. Comparisons of the xenolith anisotropies with field observations of Pn anisotropy and SKS shear wave splitting in the region suggest that foliation is horizontal in the upper layer of the lithospheric mantle and vertical in the middle and lower layers. The depth variation in mantle properties and complexity in central Europe is the result of Devonian to Early Carboniferous convergence, continental accretion, and crustal thickening, followed by Late Carboniferous to Permian extension and gravitational collapse and final modification by Neogene rifting, thinning, and magmatic heating.

  13. Petrological evidence for non-linear increase of magmatic intrusion rates before eruption at open vent mafic volcanoe

    NASA Astrophysics Data System (ADS)

    Ruth, D. C. S.; Costa Rodriguez, F.

    2015-12-01

    The most active volcanoes on earth erupt in a yearly to decadal time scales, typically erupt mafic magmas and are open-vent systems with prominent degassing plumes (e.g. Mayon, Arenal, Llaima, Etna). Here we investigate the plumbing systems, dynamics, and processes that drive eruptions at these systems. These are key questions for improving hazard evaluation, and better understanding the unrest associated with these types of volcanoes. The petrology and geochemistry from six historical eruptions (1947-2006) of Mayon volcano (Philippines) shows that all lavas are basaltic andesite with phenocrysts of plagioclase + orthopyroxene (Opx) + clinopyroxene. Opx crystals show a variety of compositions and zoning patterns (reverse, normal or complex) with Mg# (= 100 *Mg/[Mg+Fe]) varying from 67 to 81. The simplest interpretation is that the low Mg# parts of the crystals resided on an upper crustal and crystal rich reservoir that was intruded by more primitive magmas from which the high Mg# parts of the crystals grew. Modelling Mg-Fe diffusion in Opx shows that times since magma injection and eruption range from a few days up to 3.5 years in all of the investigated eruptions. The longest diffusion times are shorter than the repose times between the eruptions, which implies that crystal recycling between eruptive events is negligible. This is a surprising result that shows that for each eruption a different part of the evolved crystal-rich plumbing system is activated. This can be due to random intrusion location or an irreversibility of the plumbing system that prevents multiple eruptions from the same crystal-rich part. Moreover, we find that the number of intrusions markedly increases before each eruption in a non-linear manner. Such an increased rate of intrusions with time might reflect non-linear rheological properties of the crystal-rich system, of the enclosing rocks, or the non-linear evolution of crystal-melt reaction-dissolution fronts during magma intrusions.

  14. ALTERED RA SIGNALING IN THE GENESIS OF ETHANOL-INDUCED LIMB DEFECTS

    EPA Science Inventory

    Altered RA Signaling in the Genesis of Ethanol-Induced Limb Defects

    Johnson CS(1), Sulik KK(1,2) Hunter, ES III(3)
    (1) Dept of Cell and Developmental Biology, UNC-Chapel Hill (2) Bowles Center for Alcohol Studies, UNC-CH (3) NHEERL, ORD, US EPA, RTP, NC

    Administr...

  15. Simulation of the Genesis of Hurricane Javier (2004) in the Eastern Pacific

    NASA Technical Reports Server (NTRS)

    Braun, Scott

    2005-01-01

    NASA is preparing for the Tropical Cloud Systems and Processes (TCSP) field experiment in July 2005, a joint effort with NOAA to study tropical cloud systems and tropical cyclone genesis in the Eastern Pacific. A major thrust of the TCSP program is the improvement of the understanding and prediction of tropical cyclone genesis, intensity, motion, rainfall potential, and landfall impacts using remote sensing and in-situ data, as well as numerical modeling, particularly as they relate to the three phases of water. The Eastern Pacific has the highest frequency of genesis events per unit area of any region worldwide. African easterly waves, mesoscale convective systems (MCSs), and orographic effects are thought to play roles in the genesis of tropical cyclones there. The general consensus is that tropical depressions form in association with one or more mid-level, mesoscale cyclonic vortices that are generated within the stratiform region of the MCS precursors. To create the warm core tropical depression vortex, however, the midlevel cyclonic circulation must somehow extend down to the surface and the tangential winds must attain sufficient strength (-10 m s- ) to enable the wind-induced surface heat exchange to increase the potential energy of the boundary layer air.

  16. 75 FR 22838 - Notice of Availability of the Draft Environmental Impact Statement for the Genesis Project...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-30

    ... INFORMATION: Newmont Mining Corporation's Genesis- Bluestar mining operations area is located in northeastern... million ounces of gold from numerous mines over the last 30 years. The proposed action is to expand the... necessary haul roads and access roads, and process 60 million tons of gold-bearing ore. The proposed...

  17. Cellulose Acetate Replica Cleaning Study of Genesis Non-Flight Sample 3CZ00327

    NASA Technical Reports Server (NTRS)

    Kuhlman, K. R.; Schmeling, M.; Gonzalez, C. P.; Allton, J. H.; Burnett, D. S.

    2014-01-01

    The Genesis mission collected solar wind and brought it back to Earth in order to provide precise knowledge of solar isotopic and elemental compositions. The ions in the solar wind were stopped in the collectors at depths on the order of 10 to a few hundred nanometers. This shallow implantation layer is critical for scientific analysis of the composition of the solar wind and must be preserved throughout sample handling, cleaning, processing, distribution, preparation and analysis. We are working interactively with the community of scientists analyzing Genesis samples, using our unique laboratory facilities -- and, where needed, our unique cleaning techniques -- to significantly enhance the science return from the Genesis mission. This work is motivated by the need to understand the submicron contamination on the collectors in the Genesis payload as recovered from the crash site in the Utah desert, and -- perhaps more importantly -- how to remove it. That is, we are evaluating the effectiveness of the wet-chemical "cleaning" steps used by various investigators, to enable them to design improved methods of stripping terrestrial contamination from surfaces while still leaving the solar-wind signal intact.

  18. From lepton protoplasm to the genesis of hadrons

    NASA Astrophysics Data System (ADS)

    Eliseev, S. M.; Kosmachev, O. S.

    2016-01-01

    Theory of matter under extreme conditions opens a new stage in particle physics. It is necessary here to combine Dirac's elementary particle physics with Prigogine's dynamics of nonequilibrium systems. In the article we discuss the problem of the hierarchy of complexity. What can be considered as the lowest level of the organization of extreme matter on the basis of which the self-organization of the complex form occur?

  19. Petrological imaging of an active pluton beneath Cerro Uturuncu, Bolivia

    NASA Astrophysics Data System (ADS)

    Muir, Duncan D.; Blundy, Jon D.; Hutchinson, Michael C.; Rust, Alison C.

    2014-03-01

    Uturuncu is a dormant volcano in the Altiplano of SW Bolivia. A present day ~70 km diameter interferometric synthetic aperture radar (InSAR) anomaly roughly centred on Uturuncu's edifice is believed to be a result of magma intrusion into an active crustal pluton. Past activity at the volcano, spanning 0.89 to 0.27 Ma, is exclusively effusive and almost all lavas and domes are dacitic with phenocrysts of plagioclase, orthopyroxene, biotite, ilmenite and Ti-magnetite plus or minus quartz, and microlites of plagioclase and orthopyroxene set in rhyolitic groundmass glass. Plagioclase-hosted melt inclusions (MI) are rhyolitic with major element compositions that are similar to groundmass glasses. H2O concentrations plotted versus incompatible elements for individual samples describe a trend typical of near-isobaric, volatile-saturated crystallisation. At 870 °C, the average magma temperature calculated from Fe-Ti oxides, the average H2O of 3.2 ± 0.7 wt% and CO2 typically <160 ppm equate to MI trapping pressures of 50-120 MPa, approximately 2-4.5 km below surface. Such shallow storage precludes the role of dacite magma emplacement into pre-eruptive storage regions as being the cause of the observed InSAR anomaly. Storage pressures, whole-rock (WR) chemistry and phase assemblage are remarkably consistent across the eruptive history of the volcano, although magmatic temperatures calculated from Fe-Ti oxide geothermometry, zircon saturation thermometry using MI and orthopyroxene-melt thermometry range from 760 to 925 °C at NNO ± 1 log. This large temperature range is similar to that of saturation temperatures of observed phases in experimental data on Uturuncu dacites. The variation in calculated temperatures is attributed to piecemeal construction of the active pluton by successive inputs of new magma into a growing volume of plutonic mush. Fluctuating temperatures within the mush can account for sieve-textured cores and complex zoning in plagioclase phenocrysts

  20. Bedform genesis and evolution in bedrock substrates: a new experimental approach

    NASA Astrophysics Data System (ADS)

    Parsons, D. R.; Yin, N.; Peakall, J.

    2014-12-01

    Most previous studies on the genesis and evolution of bedforms have focused on aggradational bedforms within cohesionless sediments, with very few investigations that concern either erosive bedform genesis and evolution or bedrock channel abrasion processes. The study presented here details experiments that involve the genesis and formation of erosional bedform features within natural (soft clay) cohesive sediment beds and analogue bedrock substrates by modelling clay under the effect of both open-channel plain water flows, and sediment-laden flows. A new approach without using plaster-of-Paris or real bedrock developed provides a feasible method to simulate the genesis and evolution of the erosional bedforms in cohesive sediment beds and sculpted forms in bedrock channels on relatively short time-scales in the laboratory by using a realistic substrate substitute.A series of flume experiments are presented herein where the undrained shear strength of two different kinds of substrate material is systematically varied under constant flow conditions. Experiments using plain water flow indicated that erosive bedforms in cohesive sediment substrate cannot be produced only under the effect of sediment-free flow. Particulate-laden flows do form erosional bedforms in both kinds of clay beds and the shear strength of the bed material plays a key role in determining the diversity of erosional features forming on such substrates. Optimisation of modelling clay beds has enabled us to successfully replicate a suite of bedrock bedforms, including potholes, flutes, longitudinal furrows, etc., that have clear equivalents to those observed in bedrock rivers and contributed to investigate the genesis and evolution process of them and explore the flow structures within and above them in experimental analogue bedrock substrate for the first time.

  1. Interactive computer programs for petrologic modeling with extended Q-mode factor analysis

    USGS Publications Warehouse

    Miesch, A.T.

    1976-01-01

    An extended form of Q-mode factor analysis may be used if the row-sums of the data matrix are constant and can be helpful especially in developing and testing petrologic-mixing models for igneous systems. The first step is to represent the sample compositions as unit vectors in M-dimensional space and then to project them into space of fewer dimensions (m) as determined to be appropriate from a factor-variance diagram. Compositions thought to be those of possible end-members in the petrologic system then are represented as vectors in the M-dimensional space and projected into the same space as the sample vectors. If these vectors remain close to unity in length after projection, the corresponding compositions can serve as end-member compositions for the model. After m suitable end-member compositions have been identified, each sample composition is expressed as a mixture of the end-members by computation of the composition loadings. The interactive computer programs presented are useful in these procedures because of the trial-and-error nature of the modeling procedures. ?? 1976.

  2. Towards Calibrating the Vestan Regolith: Correlating the Petrology, Chemistry and Spectroscopy of Howardites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Ammannito, E.; Hiroi, T.; De Angelis, S.; Di Iorio, T.; Pieters, C. M.; De Sanctis, C.

    2013-01-01

    The Dawn spacecraft carries a visible and infrared mapping spectrometer (VIR) [1] that has acquired spectra for the wavelength range 0.25-5.0 µm at various spatial resolutions covering much of the vestan surface [2]. Through comparison of VIR spectra with laboratory spectra of howardite, eucrite and diogenite meteorites, the distribution of more diogenite-rich and more eucrite-rich terranes on Vesta have been mapped [3], but these maps are qualitative in nature. The available laboratory spectra are not well-integrated with detailed sample petrology or composition limiting their utility for lithologic mapping. Importantly, howardites are now recognized to come in two subtypes, regolithic and fragmental [4]. The former are breccias assembled in part from true regolith, while the latter have had much less exposure to the space environment. We are attempting to develop a more quantitative basis for mapping the distribution of lithologic types on Vesta through acquiring laboratory spectra on splits of howardites that have been petrologically and chemically characterized [5]. Noble gas analyses have been done on some allowing identification of those howardites that have been exposed in the true regolith of Vesta [6].

  3. Petrology and Geochemistry of Unbrecciated Harzburgitic Diogenite MIL 07001: A Window Into Vestan Geological Evolution

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Peng, Z. X.; Mertzman, S. A.; Mertzman, K. R.

    2014-01-01

    There is a strong case that asteroid 4 Vesta is the parent of the howardite, eucrite and diogenite (HED) meteorites. Models developed for the geological evolution of Vesta can satisfy the compositions of basaltic eucrites that dominate in the upper crust. The bulk compositional characteristics of diogenites - cumulate harzburgites and orthopyroxenites from the lower crust - do not fit into global magma ocean models that can describe the compositions of basaltic and cumulate eucrites. Recent more detailed formation models do make provision for a more complicated origin for diogenites, but this model has yet to be completely vetted. Compositional studies of bulk samples has led to the hypothesis that many diogenites were formed late by interaction of their parent melts with a eucritic crust, but those observations may alternatively be explained by subsolidus equilibration of trace elements between orthopyroxene and plagioclase and Ca-phosphate in the rocks. Differences in radiogenic Mg-26 content between diogenites and eucrites favors early formation of the former, not later formation. Understanding the origin of diogenites is crucial for understanding the petrologic evolution of Vesta. We have been doing coordinated studies of a suite of diogenites including petrologic investigations, bulk rock major and trace element studies, and in situ trace element analyses of orthopyroxene. Here we will focus on an especially unusual, and potentially key, diogenite, MIL 07001.

  4. Petrological and seismic precursors of the paroxysmal phase of the last Vesuvius eruption on March 1944

    NASA Astrophysics Data System (ADS)

    Pappalardo, Lucia; D'Auria, Luca; Cavallo, Andrea; Fiore, Stefano

    2014-09-01

    Abrupt transitions in style and intensity are common during volcanic eruptions, with an immediate impact on the surrounding territory and its population. Defining the factors trigger such sudden shifts in the eruptive behavior as well as developing methods to predict such changes during volcanic crises are crucial goals in volcanology. In our research, the combined investigation of both petrological and seismic indicators has been applied for the first time to a Vesuvius eruption, that of March 1944 that caused the present dormant state of the volcano. Our results contribute to elucidate the evolution of the conduit dynamics that generated a drastic increase in the Volcanic Explosivity Index, associated to the ejection of huge amount of volcanic ash. Remarkably, our study shows that the main paroxysm was announced by robust changes in petrology consistent with seismology, thus suggesting that the development of monitoring methods to assess the nature of ejected juvenile material combined with conventional geophysical techniques can represent a powerful tool for forecasting the evolution of an eruption towards violent behavior. This in turn is a major goal in volcanology because this evidence can help decision-makers to implement an efficient safety strategy during the emergency (scale and pace of evacuation).

  5. Petrological and seismic precursors of the paroxysmal phase of the last Vesuvius eruption on March 1944

    PubMed Central

    Pappalardo, Lucia; D'Auria, Luca; Cavallo, Andrea; Fiore, Stefano

    2014-01-01

    Abrupt transitions in style and intensity are common during volcanic eruptions, with an immediate impact on the surrounding territory and its population. Defining the factors trigger such sudden shifts in the eruptive behavior as well as developing methods to predict such changes during volcanic crises are crucial goals in volcanology. In our research, the combined investigation of both petrological and seismic indicators has been applied for the first time to a Vesuvius eruption, that of March 1944 that caused the present dormant state of the volcano. Our results contribute to elucidate the evolution of the conduit dynamics that generated a drastic increase in the Volcanic Explosivity Index, associated to the ejection of huge amount of volcanic ash. Remarkably, our study shows that the main paroxysm was announced by robust changes in petrology consistent with seismology, thus suggesting that the development of monitoring methods to assess the nature of ejected juvenile material combined with conventional geophysical techniques can represent a powerful tool for forecasting the evolution of an eruption towards violent behavior. This in turn is a major goal in volcanology because this evidence can help decision-makers to implement an efficient safety strategy during the emergency (scale and pace of evacuation). PMID:25199537

  6. Petrological and seismic precursors of the paroxysmal phase of the last Vesuvius eruption on March 1944.

    PubMed

    Pappalardo, Lucia; D'Auria, Luca; Cavallo, Andrea; Fiore, Stefano

    2014-01-01

    Abrupt transitions in style and intensity are common during volcanic eruptions, with an immediate impact on the surrounding territory and its population. Defining the factors trigger such sudden shifts in the eruptive behavior as well as developing methods to predict such changes during volcanic crises are crucial goals in volcanology. In our research, the combined investigation of both petrological and seismic indicators has been applied for the first time to a Vesuvius eruption, that of March 1944 that caused the present dormant state of the volcano. Our results contribute to elucidate the evolution of the conduit dynamics that generated a drastic increase in the Volcanic Explosivity Index, associated to the ejection of huge amount of volcanic ash. Remarkably, our study shows that the main paroxysm was announced by robust changes in petrology consistent with seismology, thus suggesting that the development of monitoring methods to assess the nature of ejected juvenile material combined with conventional geophysical techniques can represent a powerful tool for forecasting the evolution of an eruption towards violent behavior. This in turn is a major goal in volcanology because this evidence can help decision-makers to implement an efficient safety strategy during the emergency (scale and pace of evacuation). PMID:25199537

  7. Thermal modeling of the southern Alaska subduction zone: Insight into the petrology of the subducting slab and overlying mantle wedge

    SciTech Connect

    Ponko, S.C.; Peacock, S.M.

    1995-11-10

    This report discusses a two-dimensional thermal model of the southern Alaska subduction zone. This model allows specfic predictions to be made about the pressure-temperature conditions and mineralogy of the subducting oceanic crust and the mantle wedge and assess different petrologic models for the generation of Alaskan arc magmas.

  8. Petrologic insights into basaltic volcanism at historically active Hawaiian volcanoes: Chapter 6 in Characteristics of Hawaiian volcanoes

    USGS Publications Warehouse

    Helz, Rosalind L.; Clague, David A.; Sisson, Thomas W.; Thornber, Carl R.

    2014-01-01

    Contributions to our knowledge of the nature of the mantle source(s) of Hawaiian basalts are reviewed briefly, although this is a topic where debate is ongoing. Finally, our accumulated petrologic observations impose constraints on the nature of the summit reservoirs at Kīlauea and Mauna Loa, specifically whether the summit chamber has been continuous or segmented during past decades.

  9. Origin of New Faculty in Sedimentary Petrology at Ph.D.-Granting Universities in the United States and Canada.

    ERIC Educational Resources Information Center

    Thornton, Scott E.

    1981-01-01

    To aid prospective graduate students in sedimentary petrology who wish to teach at colleges or universities, 121 doctoral graduates in this field are traced to their present appointments in higher education. Only 31 percent of these graduates attained this career goal. (Author/WB)

  10. Restoration and Synthesis of Lunar Geochemical and Petrological Sample Data to Support Future Science (MoonDB)

    NASA Astrophysics Data System (ADS)

    Lehnert, K. A.; Evans, C.; Todd, N.; Zeigler, R.

    2015-06-01

    We will introduce MoonDB, a project that will synthesize geochemical and petrological data of lunar samples from the literature and unpublished data that are at risk of being lost to advance access and utility of these data for future research.

  11. Hydrothermal alteration and tectonic setting of intrusive rocks from East Brawley, Imperial Valley: an application of petrology to geothermal reservoir analysis

    SciTech Connect

    Keskinen, M.; Sternfeld, J.

    1982-01-01

    A geothermal well near East Brawley intersected a series of thin (3 to 35m) diabasic to dioritic intrusives. The petrology and chemistry of these meta-igneous rocks can provide insight into the thermal and fluid chemical characteristics of the reservoir and into the processes of magma generation at depth. A description of the rock types and their hydrothermal alteration is presented in order to increase the petrologic data base relating to this important facet of the geothermal potential of the Salton Trough and to provide a case study illustrating how detailed petrologic examination of well cuttings can provide important input in the construction of a geothermal reservoir model.

  12. Composition and Petrology of HED Polymict Breccias: The Regolith of (4) Vesta

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Cartwright, J. A.; Herrin, J. S.; Mertzman, S. A.; Mertzman, K. R.; Peng, Z. X.; Quinn, J. E.

    2012-01-01

    The polymict breccias of the howardite, eucrite and diogenite (HED) clan of meteorites preserve records of regolith processes that occur on Vesta, their putative home world. These breccias -- howardites, polymict eucrites and polymict diogenites -- are impact-engendered mixtures of diogenites and eucrites. The compositions of polymict breccias can be used to constrain the lithologic diversity of the vestan crust and the excavation depths of these materials. We have done petrological and compositional studies of multiple samples of 5 polymict eucrites and 28 howardites to investigate these issues. Older analyses were done on samples of approx 0.5 gram mass by INAA; newer analyses on samples of approx 5 gram mass by XRF and ICP-MS. We estimate the percentage of eucritic material (POEM) of polymict breccias by comparing their Al and/or Ca contents to those of average basaltic eucrite and diogenite. Our samples have POEM ranging from 28 to 98; adding two polymict diogenites from extends the range to POEM 10. One hypothesis is that ancient, well-mixed vestan regolith has POEM approx 67 and has a higher content of admixed impactor material. Several of our howardites have POEM of 59-74 (Al and/or Ca contents +/- 10% of POEM 67); about a third have Ni contents >300 micro g/g suggesting they contain >2% chondritic material (CM and/or CR). These may be regolithic howardites. Only one (LEW 85313) contains Ne dominated by a solar wind (SW) component. PCA 02066 is dominated by impact-melt material of polymict parentage and petrologically appears to be a mature regolith breccia, yet it does not contain SW-Ne. GRO 95602 falls within the POEM window, contains SW-Ne], yet has a Ni content of 193 micro g/g. Its petrologic characteristics suggest it was formed from immature regolith (no polymict breccia clasts; no glass). Trace element characteristics of the polymict breccias demonstrate the dominance of main-group eucrites as the basaltic component. Mixing diagrams of Zr, Nb, Ba, Hf

  13. Teaching Mineralogy, Petrology and Geochemistry in the 21st Century: Instructional Resources for Geoscience Faculty

    NASA Astrophysics Data System (ADS)

    Mogk, D. W.; Beane, R. J.; Whitney, D. L.; Nicolaysen, K. E.; Panero, W. R.; Peck, W. H.

    2011-12-01

    Mineralogy, petrology and geochemistry (MPG) are pillars of the geoscience curriculum because of their relevance in interpreting Earth history and processes, application to geo-hazards, resources, and environmental issues, and contributions to emerging fields such as geology and human health. To keep faculty current in scientific advances in these fields, and in modern instructional methods, the On the Cutting Edge program convened a workshop at the University of Minnesota in August, 2011. This workshop builds on the previous 15 year's work that has been focused on identifying, aggregating, and developing high-quality collections of teaching activities and related resources, and in building a community of scholars in support of excellence in instruction in MPG courses. The goals of the workshop were to: a) develop an integrated, comprehensive and reviewed curriculum for MPG courses, and to seek ways to make connections with the larger geoscience curriculum; b) to explore emerging topics in MPG such as geobiology and climate change; c) demonstrate effective methods in teaching MPG in the context of Earth system science; d) share effective teaching activities and strategies for the classroom, laboratory and field including advances in pedagogy, assessments and research on learning; e) keep faculty current on recent advances in mineralogy, petrology and geochemistry research and to apply these findings to our teaching; f) explore and utilize current societal and global issues that intersect mineralogy, petrology and geochemistry to heighten the relevancy of course content for students; and h) meet colleagues and foster future teaching and research collaborations. A significant outcome of this workshop is a peer reviewed of collection of 300+ existing teaching activities, and a gap analysis to identify teaching activities needed to make these collections comprehensive and coherent. In addition, a series of thematic collections were developed to assist high priority

  14. Mitochondrial Protein Import and the Genesis of Steroidogenic Mitochondria

    PubMed Central

    Midzak, Andrew; Rone, Malena; Aghazadeh, Yassaman; Culty, Martine; Papadopoulos, Vassilios

    2010-01-01

    The principal site of regulation of steroid hormone biosynthesis is the transfer of cholesterol from the outer to inner mitochondrial membrane. Hormonal stimulation of steroidogenic cells promotes this mitochondrial lipid import through a multi-protein complex, termed the transduceosome, spanning the two membranes. The transduceosome complex is assembled from multiple proteins, such as the steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and requires their targeting to the mitochondria for transduceosome function. The vast majority of mitochondrial proteins, including those participating in cholesterol import, are encoded in the nucleus. Their subsequent mitochondrial incorporation is performed through a series of protein import machineries located in the outer and inner mitochondrial membranes. Here we review our current knowledge of the mitochondrial cholesterol import machinery of the transduceosome. This is complemented with descriptions of mitochondrial protein import machineries and mechanisms by which these machineries assemble the transduceosome in steroidogenic mitochondria. PMID:21147195

  15. Genesis of highland basalt breccias - A view from 66095

    NASA Technical Reports Server (NTRS)

    Garrison, J. R., Jr.; Taylor, L. A.

    1980-01-01

    Electron microprobe and defocused beam analyses of the lunar highland breccia sample 66095 show it consists of a fine-grained subophitic matrix containing a variety of mineral and lithic clasts, such as intergranular and cataclastic ANT, shocked and unshocked plagioclase, and basalts. Consideration of the chemistries of both matrix and clasts provides a basis for a qualitative three-component mixing model consisting of an ANT plutonic complex, a Fra Mauro basalt, and minor meteoric material.

  16. Modular and Manufactured Houses Offer Homeowners the Building America and ENERGY STAR(R) Advantage: Genesis Homes -- Auburn Hills, Michigan

    SciTech Connect

    Not Available

    2002-01-01

    Genesis Homes is headquartered in Auburn, Michigan, and has 11 factories throughout the nation. They build modular and manufactured homes with quality design, construction practice, and building materials that qualify for the Energy Star label.

  17. Cleaning Genesis Mission Payload for Flight with Ultra-Pure Water and Assembly in ISO Class 4 Environment

    NASA Technical Reports Server (NTRS)

    Allton, Judith H.

    2012-01-01

    Genesis mission to capture and return to Earth solar wind samples had very stringent contamination control requirements in order to distinguish the solar atoms from terrestrial ones. Genesis mission goals were to measure solar composition for most of the periodic table, so great care was taken to avoid particulate contamination. Since the number 1 and 2 science goals were to determine the oxygen and nitrogen isotopic composition, organic contamination was minimized by tightly controlling offgassing. The total amount of solar material captured in two years is about 400 micrograms spread across one sq m. The contamination limit requirement for each of C, N, and O was <1015 atoms/sq cm. For carbon, this is equivalent to 10 ng/cm2. Extreme vigilance was used in pre-paring Genesis collectors and cleaning hardware for flight. Surface contamination on polished silicon wafers, measured in Genesis laboratory is approximately 10 ng/sq cm.

  18. Preliminary Quantification of Image Color Gradient on Genesis Concentrator Silicon Carbine Target 60001

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Calaway, M. J.; Rodriquez, M. C.

    2008-01-01

    The Genesis spacecraft concentrator was a device to focus solar wind ions onto a 6-cm diameter target area, thus concentrating the solar wind by 20X [1]. The target area was comprised of 4 quadrants held in place by a gold-coated stainless steel "cross" (Fig. 1). To date, two SiC and one chemical vapor deposited (CVD) quadrants have been imaged at 5X using a Leica DM-6000M in autoscan mode. Complete imaging of SiC sample 60001 required 1036 images. The mosaic of images is shown in Fig. 2 and position of analyzed areas in Fig. 3. This mosaic imaging is part of the curatorial documentation of surface condition and mapping of contamination. Higher magnification (50X) images of selected areas of the target and individual contaminant particles are compiled into reports which may be requested from the Genesis Curator [2].

  19. Cleaning Surface Particle Contamination with Ultrapure Water (UPW) Megasonic Flow on Genesis Array Collectors

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Calaway, Michael J.; Hittle, J. D.; Rodriquez, M. C.; Stansbery, E. K.; McNamara, K. M.

    2006-01-01

    The hard landing experienced by the Genesis sample return capsule breached the science canister containing the solar wind collectors. This impact into the damp lakebed contaminated collector surfaces with pulverized collector and spacecraft materials and Utah sediment and brine residue. The gold foil, polished aluminum, and bulk metallic glass remained intact, but the solar wind bulk and regime-specific array collectors were jarred loose from their frames and fractured into greater than 10,000 specimens. After a year of investigation and cleaning experimentation, the Genesis Science Team determined that array collectors had 4 classes of contaminants: particles, molecular film, submicron inorganic particulate ("aerosol"), and pre-launch surface contamination. We discuss here use of megasonically energized ultrapure water (UPW) for removing particulate debris from array collector fragments.

  20. GENESI-DR: Discovery, Access and on-Demand Processing in Federated Repositories

    NASA Astrophysics Data System (ADS)

    Cossu, Roberto; Pacini, Fabrizio; Parrini, Andrea; Santi, Eliana Li; Fusco, Luigi

    2010-05-01

    GENESI-DR (Ground European Network for Earth Science Interoperations - Digital Repositories) is a European Commission (EC)-funded project, kicked-off early 2008 lead by ESA; partners include Space Agencies (DLR, ASI, CNES), both space and no-space data providers such as ENEA (I), Infoterra (UK), K-SAT (N), NILU (N), JRC (EU) and industry as Elsag Datamat (I), CS (F) and TERRADUE (I). GENESI-DR intends to meet the challenge of facilitating "time to science" from different Earth Science disciplines in discovery, access and use (combining, integrating, processing, …) of historical and recent Earth-related data from space, airborne and in-situ sensors, which are archived in large distributed repositories. In fact, a common dedicated infrastructure such as the GENESI-DR one permits the Earth Science communities to derive objective information and to share knowledge in all environmental sensitive domains over a continuum of time and a variety of geographical scales so addressing urgent challenges such as Global Change. GENESI-DR federates data, information and knowledge for the management of our fragile planet in line with one of the major goals of the many international environmental programmes such as GMES, GEO/GEOSS. As of today, 12 different Digital Repositories hosting more than 60 heterogeneous dataset series are federated in GENESI-DR. Series include satellite data, in situ data, images acquired by airborne sensors, digital elevation models and model outputs. ESA has started providing access to: Category-1 data systematically available on Internet; level 3 data (e.g., GlobCover map, MERIS Global Vegetation Index); ASAR products available in ESA Virtual Archive and related to the Supersites initiatives. In all cases, existing data policies and security constraints are fully respected. GENESI-DR also gives access to Grid and Cloud computing resources allowing authorized users to run a number of different processing services on the available data. The GENESI

  1. Using Image Pro Plus Software to Develop Particle Mapping on Genesis Solar Wind Collector Surfaces

    NASA Technical Reports Server (NTRS)

    Rodriquez, Melissa C.; Allton, J. H.; Burkett, P. J.

    2012-01-01

    The continued success of the Genesis mission science team in analyzing solar wind collector array samples is partially based on close collaboration of the JSC curation team with science team members who develop cleaning techniques and those who assess elemental cleanliness at the levels of detection. The goal of this collaboration is to develop a reservoir of solar wind collectors of known cleanliness to be available to investigators. The heart and driving force behind this effort is Genesis mission PI Don Burnett. While JSC contributes characterization, safe clean storage, and benign collector cleaning with ultrapure water (UPW) and UV ozone, Burnett has coordinated more exotic and rigorous cleaning which is contributed by science team members. He also coordinates cleanliness assessment requiring expertise and instruments not available in curation, such as XPS, TRXRF [1,2] and synchrotron TRXRF. JSC participates by optically documenting the particle distributions as cleaning steps progress. Thus, optical document supplements SEM imaging and analysis, and elemental assessment by TRXRF.

  2. Modeling Ellipsometry Measurements of Molecular Thin-Film Contamination on Genesis Array Samples

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Stansbery, E. K.; McNamara, K. M.

    2006-01-01

    The discovery of a molecular thin-film contamination on Genesis flown array samples changed the course of preliminary assessment strategies. Analytical techniques developed to measure solar wind elemental abundances must now compensate for a thin-film contamination. Currently, this is done either by experimental cleaning before analyses or by depth-profiling techniques that bypass the surface contamination. Inside Johnson Space Center s Genesis dedicated ISO Class 4 (Class 10) cleanroom laboratory, the selection of collector array fragments allocated for solar wind analyses are based on the documentation of overall surface quality, visible surface particle contamination greater than 1 m, and the amount of thin film contamination measured by spectroscopic ellipsometry. Documenting the exact thickness, surface topography, and chemical composition of these contaminates is also critical for developing accurate cleaning methods. However, the first step in characterization of the molecular film is to develop accurate ellipsometry models that will determine an accurate thickness measurement of the contamination film.

  3. Determining Bolide Luminous Efficiency Through Optical Observations of the Genesis Atmospheric Entry

    NASA Astrophysics Data System (ADS)

    Cooke, W. J.; Swift, W. M.; Suggs, R. M.

    2005-08-01

    The Genesis spacecraft reentry presented a unique opportunity for observationally constraining some key parameters in meteor physics, as its speed, mass, composition, and trajectory are all known with great precision - such is not the case for meteors. With this in mind, members of the Space Environments Team at NASA's Marshall Space Flight Center were deployed to northern Nevada, equipped with comparatively simple optical instrumentation to observe Genesis as it made its way through the upper atmosphere in the morning hours of September 8, 2004. This paper describes the video observations and their analysis, compares the results with a simple photometric model, and assesses the science value of using spacecraft atmospheric entries as ``calibrated meteors", particularly in regard to optical luminous efficiency. Implications for the Stardust reentry in January 2006 as well as future Shuttle reentries will be discussed.

  4. Planet Alsioff - A problem set for students of phase equilibria or metamorphic petrology

    NASA Technical Reports Server (NTRS)

    Burt, Donald M.

    1988-01-01

    This paper presents a problem set that contains questions for students of phase equilibria or metamorphic petrology concerning a hypothetical planet Alsioff, for which incomplete data are given. On this panet, the SiF4 is the major volatile and Al, Si, O, and F are the only elements present. Progressive metamorphism on Alsioff mainly involves devolatilization of fluid SiF4. The problem set includes ten questions. Some of these are concerned with possible chemical reactions that should affect water, wollastonite, or Ca-SiO3 exposed to the atmosphere of Alsioff; the mechanism of controls of the O2 and F2 contents of the Alsioffian atmosphere; and the devolatilization reactions involving SiF4 with progressive thermal metamorphism.

  5. Petrology and thermal history of type IA chondrules in the Semarkona (LL3.0) chondrite

    NASA Technical Reports Server (NTRS)

    Jones, R. H.; Scott, E. R. D.

    1989-01-01

    Detailed petrologic studies have been made of 15 type IA, Fe-poor, porphyritic olivine chondrules in Semarkona (LL3.0). Major and minor element concentrations in olivines, pyroxenes, and mesostases, and bulk composition so the chondrules are measured along with zoning profiles in the olivine and pyroxene crystals. The mineral compositions and textures are best interpreted in terms of closed system crystallization in which the olivines and pyroxenes crystallized in situ from a melt corresponding to the bulk composition of the chondrule. Relict olivine grains are not found in the chondrules. Crystallization probably occurred at a cooling rate of the order of 1000 C/hr. Precursor materials of the chondrules were composed of two components, one refractory Ca-, Al-, and Ti-rich, and one less refractory Si-, Fe-, Cr-, and Mn-rich. The evidence is consistent with Semarkona being one of the least metamorphosed ordinary chondrites.

  6. Petrology and geochemistry of lithic fragments separated from the Apollo 15 deep-drill core

    NASA Technical Reports Server (NTRS)

    Lindstrom, M. M.; Nielsen, R. L.; Drake, M. J.

    1977-01-01

    Petrological and geochemical analysis of lithic fragments separated from the Apollo 15 deep-drill core showed these fragments to fall into the essentially the same range of rock types as observed in surface soil samples and large rock samples. Three particles are singled out as being of special interest. One sample is a mare basalt containing extremely evolved phases. The particle may represent small-scale imperfect crystal/liquid separation in a lava flow. A green glass particle is not the ultramafic emerald green glass described from the Apollo 15 site, but rather an ANT-like light green color, and has a quite different chemical composition from the ultramafic variety. One mare basalt displays a positive Eu anomaly and is enriched in plagioclase relative to olivine plus pyroxene.

  7. Magnetic petrology of eastern North America diabases. I - Olivine-normative dikes from western South Carolina

    NASA Technical Reports Server (NTRS)

    Warner, Richard D.; Wasilewski, Peter J.

    1990-01-01

    The oxide mineralogy and the magnetic behavior of 15 olivine-normative samples obtained from South-Caroline diabase dikes were investigated using electron microprobe and SEM analyses and measurements of natural remanence magnetization (NRM), saturation isothermal remanence magnetization (SIRM), and anhysteritic remanence magnetization. It was found that chromite (which for these olivine-normative diabases is a sensitive petrologic indicator) constitutes up to 0.5 vol pct and that its abundance and composition correlate with bulk rock Cr. Microscopic analyses showed that titanomagnetite compositions were mostly between 0.4 and 0.55. The values of NRM and the NRM/SIRM ratios varied between 4 and 0.01 A sq m/kg and 0.0019 and 0.032, respectively. These properties inversely correlate with Cr content and demonstrably contrast Cr-rich and Cr-poor samples.

  8. Petrology and structure of Pwemain to Jurassic rocks near Yreka, Klamath Mountains, California

    NASA Astrophysics Data System (ADS)

    Mortimer, N.

    Rocks of the western Paleozoic and Triasic Belt (TrPz belt) of Irwin (1966) in the north eastern Klamath Mountains of California can be subdivided into the same lithotectonic units (terranes) recognized in the southern and central Klamath Mountains. In descending structural order, these are the Fort Jones, North Fork, Salmon River, Havfork and Marble Mountains terranes of Blake and others (1982). Stratigraphic and petrologic regions are consistent with the North Fork, Salmon River and eastern Hayford terranes evolved in close proximity to each other since their origin in Permian time. Faunal and sedimentological evidence suggest that the North Fork terrane was probably at least hundreds of kilometers distant from North America in Permian time, but was close to the continent by early Jurassic time. The structural and metamorphic history of the terranes is consistent with assembly of the TrPz belt in a single, evolving middle and late Jurassic arc/subduction system.

  9. Tibooburra, a new Australian meteorite find, and other carbonaceous chondrites of high petrologic grade

    NASA Astrophysics Data System (ADS)

    Fitzgerald, M. J.; Jaques, A. L.

    1982-03-01

    Petrological evidence suggests that the Tibooburra meteorite from western New South Wales, like the Allende meteorite, is a CV3 chondrite which has experienced greater metamorphic effects than others of its class. The transitional nature of its bulk composition, which is intermediate between the CO and CV chondrites, is exhibited by several elements and displayed by the multivariate techniques of cluster analysis and principal component analysis. Tibooburra therefore resembles such CV chondrites as Coolidge and Karoonda, which have accreted early in the history of the Vigarano parent body and consequently possess a higher content of high-temperature, Ca-Al-rich inclusions with fewer low-temperature matrix and volatile phases than other CV chondrites. Both the matrix and magnesium silicate phases of these meteorites seem more iron-rich than those in later-accreted meteorites.

  10. Petrology and Geochemistry of Basic Volcanic Rocks from Saveh Region, NW Iran

    NASA Astrophysics Data System (ADS)

    Ghorbani, M.

    2002-05-01

    As part of northwestern Iran volcanic belt, Saveh region, some 130 km southwest of Tehran, is dominated by Eocene volcanic rocks. Geochemical studies on the volcanic rocks from different parts of the region have produced around 256 whole rock analyses during the last 30 years. The rocks were mainly analysed for major elements at the laboratories of the Geological Survey of Iran and Grenoble University of France using wet chemistry, XRF, and mass spectrometry techniques. Geochemical variations of the Saveh basic-intermediate volcanic rocks with 45 to 60 wt.% SiO2 content (89 samples-on an anhydrous basis) bear significant petrological implications. Here, these rocks are referred to as "basic volcanic rocks". On oxides vs. silica diagrams, data points representing the basic volcanic rocks appear as two distinct series. One is richer in Al and Ca, but poorer in Si, Na, Fe, Ti, Mn, and P than the other; these two are called Al-rich and Al-poor series respectively. Containing higher than 18 wt.% Al2O3, the Al-rich series is represented by the data contributed by Caillat et al. (1978) and Khan Nazer (1980). Al-poor series that contains less than 18 wt.% Al2O3, is best represented by the data obtained by Mehdizadeh Tehrani (1991) and Moaf Pourian (1996). It is likely that the Al-poor series has undergone a major low pressure plagioclase ñ olivine fractionation, as compared to the Al-rich series which has been affected by a lesser degree of low pressure differentiation if at all. The two series, also show different spatial disrtibution. The Al-rich series corresponds with the samples collected from the western part of the Saveh region, while the Al-poor series is found in the other parts of Saveh region. It looks that the magma supply to the western part of the region has been faciliated by deep-seated plumbing system, while in other parts of the Saveh region, development of low-level magma chambers caused accumulation of magmas in the crust, where they have undergone low

  11. Global petrologic variations on the moon: a ternary-diagram approach.

    USGS Publications Warehouse

    Davis, P.A.; Spudis, P.D.

    1987-01-01

    A ternary-diagram approach for determination of global petrologic variations on the lunar surface is presented that incorporates valuable improvements in our previous method of using geochemical variation diagrams. Our results are as follows: 1) the highlands contain large areas of relatively pure ferroan anorthosite; 2) the average composition of the upper lunar crust is represented by an 'anorthositic gabbro' composition; 3) KREEP/Mg-suite rocks are a minor fraction of the upper lunar crust; 4) within the farside highlands, areas of KREEP/Mg-suite rocks coincide mostly with areas of crustal thinning; 5) portions of the E limb and farside highlands have considerable amounts of a mafic, chondritic Th/Ti component (like mare basalt) whose occurrences coincide with mapped concentrations of light plains that display dark-halo craters.- from Authors

  12. Petrologic monitoring of 1981 and 1982 eruptive products from mount st. Helens.

    PubMed

    Cashman, K V; Taggart, J E

    1983-09-30

    New material from the dacite lava dome of Mount St. Helens, collected soon after the start of each successive extrusion, is subjected to rapid chemical and petrologic analysis. The crystallinity of the dacite lava produced in 1981 and 1982 is 38 to 42 percent, about 10 percent higher than for products of the explosive 1980 eruptions. This increase in crystallinity accompanies a decrease in the ratio of hornblende to hornblende plus orthopyroxene, which suggests that the volatile-rich, crystal-poor material explosively erupted in 1980 came from the top of a zoned magma chamber and that a lower, volatile-poor and crystal-rich region is now being tapped. The major-element chemistry of the dacite lava has remained essentially constant (62 to 63 percent silica) since August 1980, ending a trend of decreasing silica seen in the products of the explosive eruptions of May through August 1980. PMID:17759011

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  14. Genesis of a zoned granite stock, Seward Peninsula, Alaska

    USGS Publications Warehouse

    Hudson, Travis

    1977-01-01

    A composite epizonal stock of biotite granite has intruded a diverse assemblage of metamorphic rocks in the Serpentine Hot Springs area of north-central Seward Peninsula, Alaska. The metamorphic rocks include amphibolite-facies orthogneiss and paragneiss, greenschist-facies fine-grained siliceous and graphitic metasediments, and a variety of carbonate rocks. Lithologic units within the metamorphic terrane trend generally north-northeast and dip moderately toward the southeast. Thrust faults locally juxtapose lithologic units in the metamorphic assemblage, and normal faults displace both the metamorphic rocks and some parts of the granite stock. The gneisses and graphitic metasediments are believed to be late Precambrian in age, but the carbonate rocks are in part Paleozoic. Dating by the potassium-argon method indicates that the granite stock is Late Cretaceous. The stock has sharp discordant contacts, beyond which is a well-developed thermal aureole with rocks of hornblende hornfels facies. The average mode of the granite is 29 percent plagioclase, 31 percent quartz, 36 percent K-feldspar, and 4 percent biotite. Accessory minerals include apatite, magnetite, sphene, allanite, and zircon. Late-stage or deuteric minerals include muscovite, fluorite, tourmaline, quartz, and albite. The stock is a zoned complex containing rocks with several textural facies that are present in four partly concentric zones. Zone 1 is a discontinuous border unit, containing fine- to coarse-grained biotite granite, that grades inward into zone 2. Zone 2 consists of porphyritic biotite granite with oriented phenocrysts of pinkish-gray microcline in a coarse-grained equigranular groundmass of plagioclase, quartz, and biotite. It is in sharp, concordant to discordant contact with rocks of zone 3. Zone 3 consists of seriate-textured biotite granite that has been intruded by bodies of porphyritic biotite granite containing phenocrysts of plagioclase, K-feldspar, quartz, and biotite in an

  15. Potential contributions of metamorphic petrology studies in an ultra-deep drillhole in the southern Appalachians

    SciTech Connect

    Speer, J.A.

    1985-01-01

    The proposed, ultra-deep hole in the southeast U.S. will penetrate allochthonous, medium- to high-grade metamorphic rocks of the Inner Piedmont and Blue Ridge thrust sheets. It is anticipated that the hole will then encounter autochthonous low-grade, metasedimentary cover rocks before bottoming out in crystalline Precambrian basement rocks. Metamorphic petrology in the recent past has concentrated on unraveling the physical and chemical history (P, T, X/sub fluid/, etc.) of metamorphic rocks. The techniques that have been developed are ideally suited to the study of relatively limited samples from drill core. Detailed studies of the allochthonous and autochthonous rocks from the drillhole, combined with comparable studies of the surface rocks, by metamorphic petrologists experimented with these approaches, would give a 3-dimensional picture of the PTX evolution in the region of the ultra-deep hole, and thus an idea of the geometrical, chemical, and physical changes the rocks experienced. This would place constraints on conditions of the rocks before and after thrusting and thus any tectonic models of thrusting in the southern Appalachians. With limited sampling this could be a problem, with more complete sampling it will be an advantage. The metamorphic petrology of the rocks will provide basic support for the other studies of the drill core and drillhole, most notably geochronology and stable isotopes. It should not be forgotten that in addition to the historical metamorphism, the expected, present-day conditions in the drillhole are those of burial metamorphism. The hole will present an excellent opportunity to study such active metamorphic conditions.

  16. The Distant Morphological and Petrological Features of Shock Melt Veins in the Suizhou L6 Condrite

    SciTech Connect

    X Xie; Z Sun; M Chen

    2011-12-31

    The morphology and petrology of distinct melt veins in the Suizhou L6 chondrite have been investigated using scanning electron microscopy, electron microprobe analyses, and Raman spectroscopy, synchrotron energy-dispersive diffraction, and transmission electron microscopy. It is found that the melt veins in the Suizhou meteorite morphologically are the simplest, straightest, and thinnest among all shock veins known from meteorites. At first glance, these veins look like fine fractures, but petrologically they are solid melt veins of chondritic composition and consist of fully crystalline materials of two distinct lithological assemblages, with no glassy material remaining. The Suizhou melt veins contain the most abundant high-pressure mineral species when compared with all other veins known in chondrites. Thus, these veins in Suizhou are classified as shock veins. All rock-forming and almost all accessory minerals in the Suizhou shock veins have been transformed to their high-pressure polymorphs, and no fragments of the precursor minerals remain in the veins. Among the 11 high-pressure mineral phases identified in the Suizhou veins, three are new high-pressure minerals, namely, tuite after whitlockite, xieite, and the CF phase after chromite. On the basis of transformation of plagioclase into maskelynite, it is estimated that the Suizhou meteorite experienced shock pressures and shock temperatures up to 22 GPa and 1000 C, respectively. Shearing and friction along shock veins raised the temperature up to 1900-2000 C and the pressure up to 24 GPa within the veins. Hence, phase transition and crystallization of high-pressure minerals took place only in the Suizhou shock veins. Fast cooling of the extremely thin shock veins is regarded as the main reason that up to 11 shock-induced high-pressure mineral phases could be preserved in these veins.

  17. Basaltic Magmatism: The Dominant Factor in the Petrologic and Tectonic Evolution of the Earth

    NASA Technical Reports Server (NTRS)

    Lowman, Paul D., Jr.

    2003-01-01

    Silicate bodies such as the Moon, Mars, probably Mercury, and possibly Venus, appear to have evolved in three main stages: a first (felsic) differentiation, a late heavy bombardment, and a second (basaltic) differentiation. It has been proposed that the Earth underwent a similar sequence. This paper argues that the second differentiation, basaltic magmatism, has dominated the petrologic and tectonic evolution of the Earth for four billion years. A global andesitic crust, formed during and after accretion of the planet, was disrupted by major impacts that triggered mantle upwelling and sea-floor spreading about 4 billion years ago. The oceanic crust collectively has since been formed by basaltic volcanism, from spreading centers and mantle plumes. However, the continental crust has also been greatly affected. Basaltic underplating has promoted anatexis and diapiric intrusion of granitoids in granite-greenstone terrains, as well as providing heat for regional metamorphism. Basaltic intrusions, such as the Nipissing diabase of the Sudbury area, have added to the thickness of continental crust. Satellite magnetic surveys suggest that there are more such basaltic intrusions than previously realized; examples include the Bangui anomaly of central Africa and the Kentucky anomaly. Basaltic overplating from mafic dike swarms has repeatedly flooded continents; had it not been for erosion, they would be covered with basalt as Venus is today. The tectonic effects of basaltic volcanism on continents have only recently been realized. The World Stress Map project has discovered that continents are under horizontal compressive stress, caused by push from mid-ocean ridges, i.e., by basaltic volcanism. The stress fields are generally uniform over large intraplate areas, and could contribute to intraplate tectonism. Seafloor spreading has demonstrably been effective for at least 200 million years, and ridge push thus a contributor to tectonic activity for that long. Collectively, the

  18. Tectonic and petrologic evolution of the Western Mediterranean: the double polarity subduction model

    NASA Astrophysics Data System (ADS)

    Melchiorre, Massimiliano; Vergés, Jaume; Fernàndez, Manel; Torné, Montserrat; Casciello, Emilio

    2016-04-01

    The geochemical composition of the mantle beneath the Mediterranean area is extremely heterogeneous. This feature results in volcanic products whose geochemical features in some cases do not correspond to the geodynamic environment in which they are sampled and that is observed at present day. The subduction-related models that have been developed during the last decades to explain the evolution of the Western Mediterranean are mainly based on geologic and seismologic evidences, as well as petrography and age of exhumation of the metamorphic units that compose the inner parts of the different arcs. Except few cases, most of these models are poorly constrained from a petrologic point of view. Usually the volcanic activity that affected the Mediterranean area since Oligocene has been only used as a corollary, and not as a key constrain. This choice is strictly related to the great geochemical variability of the volcanic products erupted in the Western Mediterranean, due to events of long-term recycling affecting the mantle beneath the Mediterranean since the Variscan Orogeny, together with depletion episodes due to partial melting. We consider an evolutionary scenario for the Western Mediterranean based on a double polarity subduction model according to which two opposite slabs separated by a transform fault of the original Jurassic rift operated beneath the Western and Central Mediterranean. Our aim has been to reconstruct the evolution of the Western Mediterranean since the Oligocene considering the volcanic activity that affected this area since ~30 Ma and supporting the double polarity subduction model with the petrology of the erupted rocks.

  19. Testing variations within the Tagish Lake meteorite—I: Mineralogy and petrology of pristine samples

    NASA Astrophysics Data System (ADS)

    Blinova, Alexandra I.; Zega, Thomas J.; Herd, Christopher D. K.; Stroud, Rhonda M.

    2014-04-01

    Four samples (TL5b, TL11h, TL11i, and TL11v) from the pristine collection of the Tagish Lake meteorite, an ungrouped C2 chondrite, were studied to characterize and understand its alteration history using EPMA, XRD, and TEM. We determined that samples TL11h and TL11i have a relatively smaller proportion of amorphous silicate material than sample TL5b, which experienced low-temperature hydrous parent-body alteration conditions to preserve this indigenous material. The data suggest that lithic fragments of TL11i experienced higher degrees of aqueous alteration than the rest of the matrix, based on its low porosity and high abundance of coarse- and fine-grained sheet silicates, suggesting that TL11i was present in an area of the parent body where alteration and brecciation were more extensive. We identified a coronal, "flower"-like, microstructure consisting of a fine-grained serpentine core and coarse-grained saponite-serpentine radial arrays, suggesting varied fluid chemistry and crystallization time scales. We also observed pentlandite with different morphologies: an exsolved morphology formed under nebular conditions; a nonexsolved pentlandite along grain boundaries; a "bulls-eye" sulfide morphology and rims around highly altered chondrules that probably formed by multiple precipitation episodes during low-temperature aqueous alteration (≥100 °C) on the parent body. On the basis of petrologic and mineralogic observations, we conclude that the Tagish Lake parent body initially contained a heterogeneous mixture of anhydrous precursor minerals of nebular and presolar origin. These materials were subjected to secondary, nonpervasive parent-body alteration, and the samples studied herein represent different stages of that hydrous alteration, i.e., TL5b (the least altered) < TL11h < TL11i (the most altered). Sample TL11v encompasses the petrologic characteristics of the other three specimens.

  20. Petrologic considerations for hot dry rock geothermal site selection in the Clear Lake Region, California

    SciTech Connect

    Stimac, J.; Goff, F. ); Hearn, B.C. Jr. )

    1992-01-01

    The Clear Lake area is well known for anomalous heat flow, thermal springs, hydrothermal mineral deposits, and Quaternary volcanism. These factors, along with the apparent lack of a large reservoir of geothermal fluid north of Collayomi fault make the Clear Lake area an attractive target for hot dry rock (HDR) geothermal development. Petrologic considerations provide some constraints on site selection for HDR development. Spatial and temporal trends in volcanism in the Coast Ranges indicate that magmatism has migrated to the north with time, paralleling passage of the Mendocino triple junction and propagation of the San Andreas fault. Volcanism in the region may have resulted from upwelling of hot asthenosphere along the southern margin of the subducted segment of the Gorda plate. Spatial and temporal trends of volcanism within the Clear Lake volcanic field are similar to larger-scale trends of Neogene volcanism in the Cost Ranges. Volcanism (especially for silicic compositions) shows a general migration to the north over the {approximately}2 Ma history of the field, with the youngest two silicic centers located at Mt. Konocti and Borax Lake. The Mt. Konocti system (active from {approximately} 0.6 to 0.3 Ma) was large and long-lived, whereas the Borax Lake system is much smaller but younger (0.09 Ma). Remnants of silicic magma bodies under Mt. Konocti may be in the latter stages of cooling, whereas a magma body centered under Borax Lake may be in the early stages of development. The existence of an upper crustal silicic magma body of under Borax Lake has yet to be demonstrated by passive geophysics, however, subsurface temperatures in the area as high (> 200{degrees}C at 2000 m) as those beneath the Mt. Konocti area. Based on petrologic considerations alone, the Mt. Konocti-Borax Lake area appears to be the most logical choice for HDR geothermal development in the region.

  1. WRF Simulation of the Genesis of Hurricane Javier (2004) in the Eastern Pacific

    NASA Technical Reports Server (NTRS)

    Braun, Scott A.

    2005-01-01

    The Eastern Pacific has the highest frequency of genesis events per unit area of any region worldwide (Elsberry et al 1987). African easterly waves, mesoscale convective systems (MCSs), and topographic effects are thought to play roles in the genesis of tropical cyclones there (Frank and Clark 1980, Velasco and Fritsch 1987, Zehnder 1991, Zehnder and Gall 1991; Farfan and Zehnder 1997). Mozer and Zehnder (1996), using dry, idealized simulations of flow past a large-scale three-dimensional mountain range comparable to the Sierra Madre Mountains of Mexico, showed that upstream flow blocking led to diversion of the flow primarily to the south of the mountains. This flow diversion led to the formation of a low-level, barotropically unstable jet (at a location comparable to the Isthmus of Tehuantepec) and the continuous formation of synoptic-scale vorticity maxima, which they suggested may play a role in tropical cyclogenesis. Farfan and Zehnder (1 997) examined the synoptic-scale circulations that led to the formation of Hurricane Guillermo (1991). Using numerical simulations, they found that flow blocking led to the formation of a low-level easterly jet south of the mountains of Central America and a northeasterly (gap flow) jet over the Gulf of Tehuantepec, which combined with the flow associated with the Intertropical Convergence Zone (ITCZ) to produce a closed cyclonic circulation in the location of Guillermo s formation. As will be discussed in this paper, the evolution of the flow field that was associated with the genesis of Hurricane Javier was similar to that described in Farfan and Zehnder (1997), with well-defined topographic flow features. Here, using a high- resolution simulation with the WRF model, we investigate whether these topographically induced flows played a significant role in the genesis of Javier.

  2. A Genesis breakup and burnup analysis in off-nominal Earth return and atmospheric entry

    NASA Technical Reports Server (NTRS)

    Salama, Ahmed; Ling, Lisa; McRonald, Angus

    2005-01-01

    The Genesis project conducted a detailed breakup/burnup analysis before the Earth return to determine if any spacecraft component could survive and reach the ground intact in case of an off-nominal entry. In addition, an independent JPL team was chartered with the responsibility of analyzing several definitive breakup scenarios to verify the official project analysis. This paper presents the analysis and results of this independent team.

  3. Emerging concepts about prenatal genesis, aberrant metabolism and treatment paradigms in polycystic ovary syndrome.

    PubMed

    Witchel, Selma F; Recabarren, Sergio E; González, Frank; Diamanti-Kandarakis, Evanthia; Cheang, Kai I; Duleba, Antoni J; Legro, Richard S; Homburg, Roy; Pasquali, Renato; Lobo, Rogerio A; Zouboulis, Christos C; Kelestimur, Fahrettin; Fruzzetti, Franca; Futterweit, Walter; Norman, Robert J; Abbott, David H

    2012-12-01

    The interactive nature of the 8th Annual Meeting of the Androgen Excess and PCOS Society Annual Meeting in Munich, Germany (AEPCOS 2010) and subsequent exchanges between speakers led to emerging concepts in PCOS regarding its genesis, metabolic dysfunction, and clinical treatment of inflammation, metabolic dysfunction, anovulation and hirsutism. Transition of care in congenital adrenal hyperplasia from pediatric to adult providers emerged as a potential model for care transition involving PCOS adolescents. PMID:22661293

  4. The influence of absorbed solar radiation by Saharan dust on hurricane genesis

    NASA Astrophysics Data System (ADS)

    Bretl, Sebastian; Reutter, Philipp; Raible, Christoph C.; Ferrachat, Sylvaine; Poberaj, Christina Schnadt; Revell, Laura E.; Lohmann, Ulrike

    2015-03-01

    To date, the radiative impact of dust and the Saharan air layer (SAL) on North Atlantic hurricane activity is not yet known. According to previous studies, dust stabilizes the atmosphere due to absorption of solar radiation but thus shifts convection to regions more conducive for hurricane genesis. Here we analyze differences in hurricane genesis and frequency from ensemble sensitivity simulations with radiatively active and inactive dust in the aerosol-climate model ECHAM6-HAM. We investigate dust burden and other hurricane-related variables and determine their influence on disturbances which develop into hurricanes (developing disturbances, DDs) and those which do not (nondeveloping disturbances, NDDs). Dust and the SAL are found to potentially have both inhibiting and supporting influences on background conditions for hurricane genesis. A slight southward shift of DDs is determined when dust is active as well as a significant warming of the SAL, which leads to a strengthening of the vertical circulation associated with the SAL. The dust burden of DDs is smaller in active dust simulations compared to DDs in simulations with inactive dust, while NDDs contain more dust in active dust simulations. However, no significant influence of radiatively active dust on other variables in DDs and NDDs is found. Furthermore, no substantial change in the DD and NDD frequency due to the radiative effects of dust can be detected.

  5. Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

    DOE PAGESBeta

    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; Burnett, Donald S.; Sakaguchi, Isao; Suzuki, Taku; Itose, Satoru; Ishihara, Morio; Uchino, Kiichiro; Wieler, Rainer; et al

    2015-10-01

    The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile ismore » consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.« less

  6. Molecular Contamination on Anodized Aluminum Components of the Genesis Science Canister

    NASA Technical Reports Server (NTRS)

    Burnett, D. S.; McNamara, K. M.; Jurewicz, A.; Woolum, D.

    2005-01-01

    Inspection of the interior of the Genesis science canister after recovery in Utah, and subsequently at JSC, revealed a darkening on the aluminum canister shield and other canister components. There has been no such observation of film contamination on the collector surfaces, and preliminary spectroscopic ellipsometry measurements support the theory that the films observed on the anodized aluminum components do not appear on the collectors to any significant extent. The Genesis Science Team has made an effort to characterize the thickness and composition of the brown stain and to determine if it is associated with molecular outgassing.Detailed examination of the surfaces within the Genesis science canister reveals that the brown contamination is observed to varying degrees, but only on surfaces exposed in space to the Sun and solar wind hydrogen. In addition, the materials affected are primarily composed of anodized aluminum. A sharp line separating the sun and shaded portion of the thermal closeout panel is shown. This piece was removed from a location near the gold foil collector within the canister. Future plans include a reassembly of the canister components to look for large-scale patterns of contamination within the canister to aid in revealing the root cause.

  7. NR2A contributes to genesis and propagation of cortical spreading depression in rats.

    PubMed

    Bu, Fan; Du, Ruoxing; Li, Yi; Quinn, John P; Wang, Minyan

    2016-01-01

    Cortical spreading depression (CSD) is a transient propagating excitation of synaptic activity followed by depression, which is implicated in migraine. Increasing evidence points to an essential role of NR2A-containing NMDA receptors in CSD propagation in vitro; however, whether these receptors mediate CSD genesis in vivo requires clarification and the role of NR2A on CSD propagation is still under debate. Using in vivo CSD in rats with electrophysiology and in vitro CSD in chick retina with intrinsic optical imaging, we addressed the role of NR2A in CSD. We demonstrated that NVP-AAM077, a potent antagonist for NR2A-containing receptors, perfused through microdialysis probes, markedly reduced cortex susceptibility to CSD, but also reduced magnitude of CSD genesis in rats. Additionally, NVP-AAM077 at 0.3 nmol perfused into the contralateral ventricle, considerably suppressed the magnitude of CSD propagation wave and propagation rate in rats. This reduction in CSD propagation was also observed with TCN-201, a negative allosteric modulator selective for NR2A, at 3 μM, in the chick retina. Our data provides strong evidence that NR2A subunit contributes to CSD genesis and propagation, suggesting drugs selectively antagonizing NR2A-containing receptors might constitute a highly specific strategy treating CSD associated migraine with a likely better safety profile. PMID:27001011

  8. Molecular Substrate Alteration by Solar Wind Radiation Documented on Flown Genesis Mission Array Materials

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Stansbery, Eileen K.

    2006-01-01

    The Genesis spacecraft sampling arrays were exposed to various regimes of solar wind during flight that included: 313.01 days of high-speed wind from coronal holes, 335.19 days of low-speed inter-stream wind, 191.79 days of coronal mass ejections, and 852.83 days of bulk solar wind at Lagrange 1 orbit. Ellipsometry measurements taken at NASA s Johnson Space Center show that all nine flown array materials from the four Genesis regimes have been altered by solar wind exposure during flight. These measurements show significant changes in the optical constant for all nine ultra-pure materials that flew on Genesis when compared with their non-flight material standard. This change in the optical constant (n and k) of the material suggests that the molecular structure of the all nine ultra-pure materials have been altered by solar radiation. In addition, 50 samples of float-zone and czochralski silicon bulk array ellipsometry results were modeled with an effective medium approximation layer (EMA substrate layer) revealing a solar radiation molecular damage zone depth below the SiO2 native oxide layer ranging from 392 to 613 . This bulk solar wind radiation penetration depth is comparable to the depth of solar wind implantation depth of Mg measured by SIMS and SARISA.

  9. NR2A contributes to genesis and propagation of cortical spreading depression in rats

    PubMed Central

    Bu, Fan; Du, Ruoxing; Li, Yi; Quinn, John P; Wang, Minyan

    2016-01-01

    Cortical spreading depression (CSD) is a transient propagating excitation of synaptic activity followed by depression, which is implicated in migraine. Increasing evidence points to an essential role of NR2A-containing NMDA receptors in CSD propagation in vitro; however, whether these receptors mediate CSD genesis in vivo requires clarification and the role of NR2A on CSD propagation is still under debate. Using in vivo CSD in rats with electrophysiology and in vitro CSD in chick retina with intrinsic optical imaging, we addressed the role of NR2A in CSD. We demonstrated that NVP-AAM077, a potent antagonist for NR2A-containing receptors, perfused through microdialysis probes, markedly reduced cortex susceptibility to CSD, but also reduced magnitude of CSD genesis in rats. Additionally, NVP-AAM077 at 0.3 nmol perfused into the contralateral ventricle, considerably suppressed the magnitude of CSD propagation wave and propagation rate in rats. This reduction in CSD propagation was also observed with TCN-201, a negative allosteric modulator selective for NR2A, at 3 μM, in the chick retina. Our data provides strong evidence that NR2A subunit contributes to CSD genesis and propagation, suggesting drugs selectively antagonizing NR2A-containing receptors might constitute a highly specific strategy treating CSD associated migraine with a likely better safety profile. PMID:27001011

  10. Building an outpatient imaging center: a case study at Genesis Healthcare System, part 1.

    PubMed

    Yanci, Jim

    2006-01-01

    In the first of two parts, this article provides an outline of key steps in creating a freestanding diagnostic imaging center (Genesis HealthCare System located in Zanesville, OH) and provides details on a few of the significant processes. The following are highlighted in this article: Overview, market assessment, facility design, and equipment selection. Part 2 will feature operational process improvements. The length of the Genesis project extended to about 18 months due to the added services of urgent care and a community education and meeting facility. The project began in July 2005 and was completed in January 2006 (if the project was focused only on imaging, it could have been complete in about 8 to 10 months, see Figure 1 for a typical summary work task timeline). This multi-service outpatient center, The Genesis Healthplex on Maple, was created in an existing facility that was once a large grocery store. A significant goal that came out of the project was to create the perfect customer experience. The customer is defined as: Patients, patient families, referring physicians and their staff, radiologists, and employees. This was achieved by bringing the 3 entities of people (patient/family, staff, and physicians) working closely together by utilizing well identified processes and employing technology that the market demands. Only when these areas overlap and work together will the perfect customer experience be created. See Figure 2. PMID:17191544

  11. Genesis of the central zone of the Nolans Bore rare earth element deposit, Northern Territory, Australia

    NASA Astrophysics Data System (ADS)

    Schoneveld, Louise; Spandler, Carl; Hussey, Kelvin

    2015-08-01

    The Nolans Bore rare earth element (REE) deposit consists of a network of fluorapatite-bearing veins and breccias hosted within Proterozoic granulites of the Reynolds Range, Central Australia. Mineralisation is divided into three zones (north, central, and south-east), with the north and south-east zones consisting of massive REE-bearing fluorapatite veins, with minor brecciation and carbonate infill. The central zone is distinctively different in mineralogy and structure; it features extensive brecciation, a high allanite content, and a large, epidote-rich enveloping alteration zone. The central zone is a reworking of the original solid apatite veins that formed during the Chewings Orogeny at ca. 1525 Ma. These original apatite veins are thought to derive from phosphate-rich magmatic-hydrothermal fluid exsolved from as-yet unrecognised alkaline magmatic bodies at depth. We define four ore breccia types (BX1-4) in the central zone on the basis of detailed petrological and geochemical analysis of drillcore and thin sections. BX1 ore comprises fluorapatite with minor crackle brecciation with carbonate infill and resembles ore of the north and south-east zones. Breccia types BX2, BX3, and BX4 represent progressive stages of ore brecciation and development of calc-silicate mineral (amphibole, epidote, allanite, calcite) infill. Comparison of bulk ore sample geochemistry between breccia types indicates that REEs were not mobilised more than a few centimetres during hydrothermal alteration and brecciation. Instead, most of the REEs were partitioned from the original REE fluorapatite into newly formed allanite, REE-poor fluorapatite and minor REE carbonate in the breccias. Negative europium (Eu) anomalies in the breccia minerals are accounted for by a large positive Eu anomaly in epidote from the alteration zones surrounding the ore breccias. This observation provides a direct link between ore recrystallisation and brecciation, and the formation of the alteration halo in

  12. The added value of biomarker analysis to the genesis of Plaggic Anthrosols.

    NASA Astrophysics Data System (ADS)

    van Mourik, Jan; Jansen, Boris

    2015-04-01

    Coversands (chemical poor Late-glacial aeolian sand deposits) dominate the surface geology of an extensive area in northwestern Europe. Plaggic Anthrosols occur in cultural landscapes, developed on coversands. They are the characteristic soils that developed on ancient fertilized arable fields. Plaggic Anthrosols have a complex genesis. They are records of aspects environmental and agricultural history. In previous studies information of the soil records was unlocked by application of pollen analysis, 14C and OSL dating. In this study we applied biomarker analysis to unlock additional information about the applied organic sources in the production of plaggic manure. Radiocarbon dating suggested the start of sedentary agriculture (after a period, characterized by shifting cultivation and Celtic fields) between 3000 and 2000 BP. In previous studies is assumed that farmers applied organic sods, dug on forest soils and heath to produce organic stable manure to fertilize the fields. The mineral fraction of the sods was supposed to be responsible for the development of the plaggic horizon and the raise of the land surface. Optically stimulated Luminescence dating however suggested that plaggic deposition on the fields started relatively late, in the 18th century. The use of ectorganic matter from the forest soils must have been ended in the 10th-12th century, due to commercial forest clear cuttings as recorded in archived documents. These deforestations resulted in the first extension of sand drifting and famers had to protect the valuable heath against this ' environmental catastrophe' . The use of heath for sheep grazing and other purposes as honey production could continue till the 18th century, as recorded in archived documents. In the course of the 18th century, the population growth resulted in increasing demand for food. The deep stable economy was introduced and the booming demand for manure resulted in intensive sod digging on the heath. This caused heath

  13. Petrology and geochemistry of Mesozoic granitic rocks from the Nansha micro-block, the South China Sea: Constraints on the basement nature

    NASA Astrophysics Data System (ADS)

    Yan, Quanshu; Shi, Xuefa; Liu, Jihua; Wang, Kunshan; Bu, Wenrui

    2010-01-01

    There are several micro-blocks dispersed in the South China Sea (SCS), e.g., Xisha-Zhongsha block, Nansha block and Reed-Northeastern Palawan block, etc., but detailed petrological constraints on their basement nature were previously lacking. The magmatic ages for granitic rock samples from two dredge stations in the Nansha micro-block vary from 159 to 127 Ma, which are comparable to magmatic activities occurred in the northern margin (Pearl river mouth), HongKong and East China. Petrographic characteristics, major-, trace element and Sr-Nd isotopic data of nine samples from two dredged station performed in the Nansha micro-block, the SCS, are reported. Petrographically, these granitic rocks can be divided into two groups which underwent a complex history of magmatic process, i.e., tonalitic rock (Group I) and monzogranitic rock (Group II). The Rittmann index ( σ) for these rocks (1.9-3.1) suggest that they belong to calc-alkaline rocks. Group I rocks which is of typical I-type, have higher contents of TiO 2, Al 2O 3, FeO, MgO, CaO, Na 2O and P 2O 5, but lower values of SiO 2 and K 2O, when compared with those of Group II with I-type characteristics. Group I rocks are produced by partial melting of older Precambrian basement with the variable influence of mantle-derived magma which results from the interaction of released fluids from the subducted slab and the overlying mantle wedge in a general convergent margin setting, and Group II rocks result from partial melting of lower crustal basic rocks (amphibolite) and/or further partial melting of the Group I rocks associated with the variable influence from the underplating mantle-derived magma resulting from lithospheric extensional regime. Both Groups I and II have undergone assimilation and fractional crystallization (AFC) processes during its petrogenesis. This study therefore demonstrates that there exists a continental basement within micro-blocks in the South China Sea, and further supports the idea that a

  14. Genesis of melilitolite from Colle Fabbri: inferences from melt inclusions

    NASA Astrophysics Data System (ADS)

    Panina, L. I.; Nikolaeva, A. T.; Stoppa, F.

    2013-12-01

    Melilite and wollastonite from the Colle Fabbri stock contain silicate melt and silicate-carbonate inclusions. The homogenization temperatures of silicate inclusions are within the magmatic temperature range of mantle ultrabasic melts: about 1,320 ± 15 °С. Their composition is melilititic and evolves to the composition of leucite tephrite and phonolite. The composition of silicate-carbonate inclusions are high SiO2, Ca-rich, enriched in alkalies and are similar to that of inclusions of carbonatite melts in the minerals of melilitolites of other intrusive ultramafic complexes. They are also similar to the compositions of metasomatized travertine covering the melilitolite stock. The presence of primary silicate and silicate-carbonate inclusions evidences that the melilitite magma from which melilitolites of Colle Fabbri crystallized was associated with carbonatite liquid. This liquid was highly fluidized, mobile and aggressive. Actively interacting with overlying travertine, the liquid enriched them with alkalies, aluminosilicates and incompatible elements, which resulted in the equalization of their compositions. Heterogeneous compositional dominions were formed at the contact between melilitolite and wall pelites. In the minerals of these contact facies high-Si melt inclusions of varying composition have been observed. Their occurrence is related to the local assimilation by the high-temperature melilitite magma of pelitic country rocks. The content of incompatible elements in melilitite melts and melilitolites is higher than the mantle norm and they have peculiar indicator ratios, spectra, Eu/Eu* ratio, which suggest a peculiar mantle source.

  15. Geological setting and genesis of Archean gold deposits of Australia

    SciTech Connect

    Groves, D.I.

    1985-01-01

    Most Archaean gold production from a Australia has come from Greenstone Belts in the Western Australian Shield. On the regional scale, large deposits occur predominantly in younger rift-phase greenstones, whereas younger and older platform-phase greenstones are progressively less well mineralized. Mineralization occurs mainly within mafic volcanic or intrusive rocks, although BIF is also a significant host rock. Ores commonly occur in structural sites, typified by extensive wallrock alteration involving carbonation, K-metasomatism, and pyritization with synchronous Au deposition. Large deposits commonly have great depth extension but lack significant zoning. Sub-amphibolite facies settings are dominant. A metamorphic-replacement model explains the majority of characteristics of many of the deposits. The ore fluid and ore components were derived by devolatilization of dominantly volcanic sequence during high-grade metamorphism at the base of the greenstone pile. Gold was transported as a reduced sulfur complex in reduced, near-neutral, H/sub 2/O-CO/sub 2/ fluids of low salinity. Faults and shear zones provided fluid access to depositional sites where gold deposition occurred at 300-400C and 1-2 kb, largely in response to fluid-wallrock interaction. Pyritization of Fe-rich host rocks resulted in development of several of the larger gold deposits and other less-specific reactions produced the variety of other generally smaller deposits.

  16. U/Pb geochronologic and petrologic studies in the Blue Mountains terrane, northwestern Oregon and westernmost central Idaho: implications for pre-Tertiary tectonic evolution

    SciTech Connect

    Walker, N.W.

    1986-01-01

    This assemblage includes tectonically juxtaposed, variably deformed and metamorphosed Permo-Triassic volcanic-plutonic complexes and related sedimentary rocks, ultramafic-mafic-silicic igneous suites, polymict melange tracts, and thick sequences of Upper Triassic to Upper Cretaceous volcaniclastic sediments. Numerous undeformed mesozonal gabbroic to granodioritic plutons of Late Jurassic to Early Cretaceous age cross-cut these older rocks indicating juxtaposition of the older components took place prior to emplacement of the plutons. Field, petrologic, and U-Pb geochronologic investigation of igneous and metamorphic components of this region demonstrate the Permo-Triassic Seven Devils Group was constructed, at least in part, within and upon a Late Carboniferous basement whose protolith was plutonic. Geochemical data suggest this basement is of oceanic origin. Regional U-Pb geochronologic data from pre-Jurassic igneous and meta-igneous components throughout this region reveal an age range of plutonic activity of 279 Ma to 215 Ma. This fact considered in concern with field evidence, paleomagnetic evidence, and paleontologic data supports the conclusion that although there are distinct structural/stratigraphic blocks within this region, they are vestiges of a single, ensimatic convergent margin system that was magmatically and tectonically active intermittently from Early Permian to Early Cretaceous time.

  17. Genesis of the Silsilah tin deposit, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Kamilli, Robert J.; Criss, R.E.

    1996-01-01

    The Silsilah tin deposit (lat 25 degrees 06' N, long 42 degrees 40' E) consists of a group of pervasively greisenized, flat-topped granite cupolas within a 12-km-diam ring complex. The greisens contain varying amounts of disseminated cassiterite and wolframite. Several types of quartz veins are peripheral to the greisens; some of these contain minor wolframite. The deposit is genetically associated with a highly differentiated, peraluminous alkali-feldspar granite (587 + or - 8 Ma) that is part of a mostly peralkaline, igneous ring complex intruded into Late Proterozoic, immature sandstones of the Murdama Group. We recognize four distinct phases of the peraluminous granite. Only the smallest, most highly differentiated cupolas contain significant tin greisen mineralization. Greisens developed beneath aplitic carapaces that overlie the granite and created impermeable barriers to rising volatiles. The geometry of a cupola correlates strongly with the intensity of alteration; cupolas with the smallest cross sectional areas and steepest marginal contacts have the most intensely greisenized apexes. The paragenetic sequence can be divided into five stages: pegmatite formation, locally pervasive albitization, locally pervasive greisenization and deposition of cassiterite, deposition of quartz-wolframite veins, and deposition of quartz veins with minor base metal sulfides. Pressure-corrected fluid inclusion filling temperatures indicate that the hydrothermal system generally cooled as it evolved and that the delta 18O values of the hydrothermal quartz increased from 10.8 to 15.7 per mil. Calculated delta 18O values of the hydrothermal fluid varied concomitantly from the pegmatite stage (delta 18O fluid approximately 8.6ppm; T [asymp] 550 degrees C) to the greisen stage (5.4 and 5.6[ppm; T [asymp] 360 degrees C), the quartz-wolframite vein stage (6.3 and 7.5ppm; T [asymp] 390 degrees C), and the late vein stage (4.0 and 5.1ppm; T [asymp] 270 degrees C). This evolution

  18. Geochemistry and petrology of Oligocene and Miocene ash-flow tuffs of the southeastern Great Basin, Nevada

    USGS Publications Warehouse

    du Bray, Edward A.

    1995-01-01

    The White River Narrows area of Southeast Nevada contains 18 regionally distributed middle Tertiary dacite to rhyolite ash-flow tuffs. Geochemical data provide an excellent opportunity to study stratigraphic and petrologic relations of these tuffs. Chemical data for each of the tuffs are distinctive and provide a significant addition to other data used to identify and correlate these units. Relatively minor compositional variation within the tuffs is noteworthy.

  19. Containerless high-pressure petrology experiments in the microgravity environment of the Space Station

    NASA Technical Reports Server (NTRS)

    Boynton, W. V.; DRAKE; HILDEBRAND; JONES; LEWIS; TREIMAN; WARK

    1987-01-01

    The genesis of igneous rocks on terrestrial planets can only be understood through experiments at pressures corresponding to those in planetary mantles (10 to 50 kbar). Such experiments typically require a piston-cylinder apparatus, and an apparatus that has the advantage of controllable pressure and temperature, adequate sample volume, rapid sample quench, and minimal danger of catastrophic failure. It is proposed to perform high-pressure and high-temperature piston-cylinder experiments aboard the Space Station. The microgravity environment in the Space Station will minimize settling due to density contrasts and may, thus, allow experiments of moderate duration to be performed without a platinoid capsule and without the sample having to touch the container walls. The ideal pressure medium would have the same temperatures. It is emphasized, however, that this proposed experimental capability requires technological advances and innovations not currently available.

  20. GENESI-DR - A single access point to Earth Science data

    NASA Astrophysics Data System (ADS)

    Cossu, R.; Goncalves, P.; Pacini, F.

    2009-04-01

    The amount of information being generated about our planet is increasing at an exponential rate, but it must be easily accessible in order to apply it to the global needs relating to the state of the Earth. Currently, information about the state of the Earth, relevant services, analysis results, applications and tools are accessible in a very scattered and uncoordinated way, often through individual initiatives from Earth Observation mission operators, scientific institutes dealing with ground measurements, service companies, data catalogues, etc. A dedicated infrastructure providing transparent access to all this will support Earth Science communities by allowing them to easily and quickly derive objective information and share knowledge based on all environmentally sensitive domains. The use of high-speed networks (GÉANT) and the experimentation of new technologies, like BitTorrent, will also contribute to better services for the Earth Science communities. GENESI-DR (Ground European Network for Earth Science Interoperations - Digital Repositories), an ESA-led, European Commission (EC)-funded two-year project, is taking the lead in providing reliable, easy, long-term access to Earth Science data via the Internet. This project will allow scientists from different Earth Science disciplines located across Europe to locate, access, combine and integrate historical and fresh Earth-related data from space, airborne and in-situ sensors archived in large distributed repositories. GENESI-DR builds a federated collection of heterogeneous digital Earth Science repositories to establish a dedicated infrastructure providing transparent access to all this and allowing Earth Science communities to easily and quickly derive objective information and share knowledge based on all environmentally sensitive domains. The federated digital repositories, seen as services and data providers, will share access to their resources (catalogue functions, data access, processing services etc

  1. Petrologic model of the northern Mississippi Embayment based on satellite magnetic and ground-based geophysical data

    NASA Technical Reports Server (NTRS)

    Thomas, H. H.

    1984-01-01

    A petrologic model of the northern Mississippi Embayment, derived from gravity, seismic and rift data, is evaluated by converting the model to a magnetization model which is compared with satellite magnetic anomaly models. A magnetization contrast of approximately -0.54 A/m, determined from the petrologic model of the embayment compares favorably to values of -0.62 A/m and -0.45 A/m from a Magsat United States Apparent Magnetization Contrast Map and a published POGO magnetization contrast model, respectively. The petrologic model suggests that the magnetic anomaly low associated with the Mississippi Embayment may be largely due to the intrusion under non-oxidizing conditions of low Curie temperature gabbroic material at the base of the crust of the embayment. Near-surface mafic plutons, bordering the Mississippi Valley Graben, appear from aeromagnetic data to have higher magnetizations than the deeper gabbroic material; however, it is impossible to ascertain if this is due to compositional differences or similar material at shallower (lower temperature) depths. These results indicate that variations in the Curie temperatures of intrusions accompanying rifting may account for a large part of the wide range of magnetic anomalies associated with presently inactive rifts with normal heat flow.

  2. Semi-empirical Gibbs free energy formulations for minerals and fluids for use in thermodynamic databases of petrological interest

    NASA Astrophysics Data System (ADS)

    Gerya, T. V.; Maresch, W. V.; Podlesskii, K. K.; Perchuk, L. L.

    2004-09-01

    The P T partition function in statistical thermodynamics can be used to derive semi-empirical formulations of the Gibbs free energy G for minerals and fluids. Parameterization of these equations includes simultaneous regression of experimental heat capacity and molar volume data, allowing fitting, appraisal and optimization of various data sources, as required in the construction of internally consistent petrological data bases. This approach can also be extended to minerals with λ-transitions and to fluids by considering the Gibbs free energy as a function of pressure P, temperature T and an ordering parameter Xα, so that accurate modelled representation and extrapolation of the thermodynamic properties of large numbers of petrologically significant minerals and coexisting fluids can be attained. The ordering parameter is chosen to denote the equilibrium mole fraction (thermodynamic probability) of ordered clusters (structural units) in a substance when G(T,P, Xα)=min. The procedure is tested on existing experimental data for the system MgO SiO2 H2O. The proposed Gibbs free energy formulation permits thermodynamic properties of minerals, fluids and phase equilibria to be described and extrapolated over a wide range of pressure (0 800 kbar) and temperature (20 3000 K), thus allowing effective use in thermodynamic data bases of petrological interest.

  3. Application of Automated SEM-EDS Based Mineral Identification Systems to Problems in Metamorphic Petrology

    NASA Astrophysics Data System (ADS)

    Fairhurst, Robert; Barrow, Wendy; Rollinson, Gavyn

    2010-05-01

    Automated scanning electron microscopy-energy dispersive x-ray spectrometer (SEM-EDS) based mineral identification systems such as QEMSCAN have been in development for over 20 years, primarily as a tool to understand mineral liberation and element distribution in metal mining industry. This powerful technique is now being used in non mining applications such as metamorphic petrology where accurate mineral identification and metamorphic fabrics are key to deciphering the metamorphic history of samples. The QEMSCAN was developed by CSIRO for application in the mining industry where it is used to understand mineralogy, texture, mineral associations, the presence of gangue minerals and deleterious elements that may potentially interfere with mineral processing and planning, and the overall impact of mineralogy on grinding and flotation processes. It is capable of identifying most rock-forming minerals in milliseconds from their characteristic x-ray spectra. The collected x-ray spectra are compared to entries in a database containing the species identification profiles (SIPs) and are assigned a label accordingly. QEMSCAN is capable of searching large sample areas at high resolution resulting in the accurate and precise determination of all minerals present. Reports that were originally developed for the mining geologist can be equally useful to the petrologist, e.g. phase/mineral maps, modal mineral abundances and mineral association reports. Identification of key minerals is of great importance to determining the petrologic history of a sample. These key minerals may be few in number and present as small microinclusions (less than 100 μm) making them difficult to identify, if at all, with the petrographic microscope. Therefore, imaging by electron-microprobe or scanning electron microscope are the methods traditionally used. However, because of the small field of view available on these instruments at a magnification necessary to resolve micron sized relicts and

  4. Petrological and geochemical data of volcanic rocks from the southern Afar Depression, Ethiopia.

    NASA Astrophysics Data System (ADS)

    Urbanek, Ch.; Faupl, P.; Richter, W.; Seidler, H.

    2003-04-01

    The geological and petrological investigations (FWF Project P15196) in the southern Afar Depression of Ethiopia support an international palaeoanthropological research-team (PAR) under the leadership of Horst Seidler. Mount Galila is the conspicuous centre of the research area [N 9° 44.101', E 40° 27.368'], situated about 20 km E of the NNE-SSW striking, recently active Hertale Graben, which represents a northernmost segment of the Main Ethiopian Rift (MER). Stratigraphically, the fossiliferous lacustrine and fluvial deposits, as well as the intercalated volcanic layers of the Galila area, belong to the "Upper Stratoid Series" (5-1.4 Ma) and will be named the Mount Galila Formation. They are similar to the Awash Group, from which very famous early hominid fossils have been described. In the Mount Galila Fm., 7 main volcanic horizons serve as marker beds comprising basalts, ignimbrites, tuffs and tuffaceous sands. The basalt horizons in the research area represent basaltic lava flows each consisting of one single flow unit c. 5 meters thick with maximum 5 cooling units. A first set of geochemical data from XRF spectrometry comprising main and trace element analysis shows characteristics for the volcanic marker beds as following: The basalts are clearly tholeiitic in the main elements (FeO/MgO/Alk) and show typical trace element distributions (e.g. Zr/Y-Zr; Ti/100-Yx3-Zr) as Within Plate Tholeiit Basalts. All basalt samples contain access 40Ar which can be explained by specific erruption mechanisms that leads to analytical problems for 40Ar/39Ar dating. In the TAS diagram after LeMaitre 1984 the ignimbrites vary at high alkali levels (7-9%) from trachytic to dacitic and rhyolitic composition, whereas at low alkali contents (<7%) they plot into the andesitic field. Compared to the basalts, the geochemistry of the ignimbrites is much more inhomogenous. Tuffs and tuffaceous sands are relevant as marker beds especially for the palaeoanthropological excavations in the

  5. Petrology and Geochemistry of the Northeast Seamounts of the Galapagos Platform

    NASA Astrophysics Data System (ADS)

    Sinton, C. W.; Harpp, K. S.; Christie, D. M.

    2010-12-01

    One of the best locations to study hotspot-ridge interactions is the Northern Galápagos Province (NGP), the region that lies between the Galapagos Spreading Center (GSC) and the central portion of the Galapagos Archipelago. The Galapagos hotspot is currently located off-axis from the GSC but still has a profound influence on the ridge in terms of axial lava composition and ridge bathymetry. The NGP is characterized by an array of volcanic lineaments that are composed of seamounts and five small islands. The eastern edge of the NGP is defined by a group of at least five seamounts (the Northeast Seamounts), three of which were mapped and dredged in 1990 during Leg 2 of the PLUME expedition of the R/V Thomas Washington. We report petrological and geochemical data from the basalts recovered at six dredge sites. All basalts are tholeiitic with a general MORB-like composition, but with considerable variation within some individual dredge hauls and between seamounts. Previously published isotopic data are limited but 3He/4He ratios (Graham et al. 1993) and Sr-Nd-Pb isotopic data (Harpp and White 2000) are consistent with a depleted mantle source for all three seamounts. Based on geochemistry and petrological observations, the basalts can be divided into at least thirteen distinct groups. The bulk of the analyzed glass samples have compositions more than MORB with MgO content of 8-10% wt., although two of the groups are in the 6-7% range. In addition, the primitive lavas have high CaO and Al2O3 . The mineralogy ranges from aphyric for the more evolved lavas to olivine + plagioclase-phyric or plagioclase ultraphyric for the more primitive basalts. The plagioclase appear to be very calcic (up to An91) xenocrysts that are often hosting aluminous spinel (Al2O3 46-48% wt.) and primitive melt inclusions (Sinton et al., 1993). Initial trace element data show light rare earth (LREE)-depleted signatures, although several samples are slightly enriched in the LREE. Taken together

  6. Core petrology: Implications for the dynamics and evolution of planetary interiors

    NASA Astrophysics Data System (ADS)

    Hauck, S. A.; Van Orman, J. A.

    2011-12-01

    the cores of the smaller terrestrial bodies in the Solar System are readily accessible in the laboratory, and allow systematic study of the petrologic behavior of the wide range of possible core systems. We discuss the potential consequences of core petrologic evolution for magnetic field generation and prospects for future progress in constraining the operation of planetary cores.

  7. Radio-induced alteration in cordierite - Implications for petrology, gemmology and materials science

    NASA Astrophysics Data System (ADS)

    Krickl, R.; Nasdala, L.; Grambole, D.; Kaindl, R.

    2009-04-01

    Cordierite is a common metamorphic and magmatic mineral, which is used as petrologic tool for reconstructing the history of its host rock. Further applications include cordierite gemstones and the use of synthetic analogs in ceramics. Cordierite is stable over a wide temperature and pressure range and relatively resistant to chemical alteration; however, its properties can be significantly changed upon the impact of external irradiation. In the course of a comprehensive study, natural radiohaloes in cordierite (a widespread feature caused by the impact of alpha-particles originating from radioactive inclusions) as well as artificial analogs produced by implantation of 8.8 MeV He2+ ions were investigated using modern micro-techniques. Additional irradiation experiments were performed using O6+ ions, electrons and gamma-rays. Ion irradiation causes yellow colouration that is strongly pleochroic, and fades at higher doses. The possibility of radiation-treatment for enhancing the quality of gem-cordierite is discussed. While samples remain crystalline up to doses of 1016 He2+/cm2, the same material is fully amorphised when irradiated with the same dose of 30 MeV O6+ ions. These different observations may help to estimate the performance assessment of cordierite-ceramics in radiated environments. A very important result concerning the petrological use of cordierite is the radio-induced transformation of channel constituents: Inside the irradiated areas the vibrational bands of CO2 decrease in intensity, whereas two new bands appear at 2135 cm-1 (both IR- and Raman-active; cf. Nasdala et al., 2006) and 1550 cm-1 (only Raman-activ). They are assigned to stretching vibrations of carbon monoxide and molecular oxygen, respectively, thus indicating a radio-chemical transformation 2CO2 → 2CO + O2 in alpha-irradiated cordierite. This study yields the first spectroscopic evidence for the irradiation-induced formation of molecular oxygen in cordierite. Polarised vibrational

  8. Cryogenian alkaline magmatism in the Southern Granulite Terrane, India: Petrology, geochemistry, zircon U-Pb ages and Lu-Hf isotopes

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    The Southern Granulite Terrane (SGT) in India preserves the records of the formation and recycling of continental crust from Mesoarchean through Paleoproterozoic to Neoproterozoic and Cambrian, involving multiple subduction-accretion-collision associated with major orogenic cycles. A chain of unmetamorphosed and undeformed alkaline magmatic intrusions occurs along the northern margin of the SGT aligned along paleo-suture zones. Here we investigate two representative plutons from this suite, the Angadimogar syenite (AM) and the Peralimala alkali granite (PM) through field, petrological, geochemical, zircon U-Pb and Lu-Hf studies. Magma mixing and mingling textures and mineral assemblages typical of alkaline rocks are displayed by these plutons. The whole-rock major and trace element data characterize their alkaline nature. In trace element discrimination diagrams, the AM rocks straddle between the VAG (volcanic-arc granites) and WPG (within plate granites) fields with most of the samples confined to the VAG field, whereas the PM rocks are essentially confined to the WPG field. The diversity in some of the geochemical features between the two plutons is interpreted to be the reflection of source heterogeneities. Most zircon grains from the AM and PM plutons display oscillatory zoning typical of magmatic crystallization although some grains, particularly those from the PM pluton, show core-rim structures with dark patchy zoned cores surrounded by irregular thin rims resulting from fluid alteration. The weighted mean 206Pb/238U ages of the magmatic zircons from three samples of the AM syenite are in the range of 781.8 ± 3.8 Ma to 798 ± 3.6 Ma and those from two samples of the PM alkali granite yield ages of 797.5 ± 3.7 Ma and 799 ± 6.2 Ma. A mafic magmatic enclave from the AM pluton shows weighted mean 206Pb/238U age of 795 ± 3.3 Ma. The AM and PM plutons also carry rare xeneocrystic zircons which define upper intercept concordia ages of 3293 ± 13 Ma and 2530

  9. Petrological insights into the storage conditions, and magmatic processes that yielded the centennial 2010 Merapi explosive eruption

    NASA Astrophysics Data System (ADS)

    Costa, Fidel; Andreastuti, Supriyati; Bouvet de Maisonneuve, Caroline; Pallister, John S.

    2013-07-01

    To understand the processes that made the 2010 eruption of Merapi much larger and more explosive than most dome-forming eruptions of the past century, we investigated the geochemistry, petrology, and pre-eruptive conditions of magmas erupted in 2006 and 2010. The juvenile rocks of 2010 are plagioclase, two-pyroxene basaltic andesites with seriate textures and minor amounts of reaction-free amphibole, Fe-Ti oxides, and rare crystals of olivine and biotite. The bulk-rock composition, mineral paragenesis, and textures are similar to those of juvenile blocks from the much less explosive eruption of 2006. One of the key differences is that most amphiboles in 2010 don't have breakdown reaction rims, whereas those of 2006 are largely reacted. We acquired > 80 X-ray distribution maps of major and minor elements of large areas (> 1 cm2) and single crystals, backscattered electron images, electron microprobe analyse, and compositional traverses across crystals. The data reveal that both the 2006 and 2010 samples are heterogeneous at various spatial scales, with numerous reaction textures between pyroxenes and amphiboles, dissolution textures, and large variations of crystal sizes, morphologies, and compositions. These features record open-system magmatic processes involving the assimilation of carbonate rocks, and interactions between various parts of Merapi's plumbing system, including a degassed shallow magma system and deep hotter and more volatile rich magma intrusions. The petrological complexity of the samples makes unraveling the pre-eruptive conditions of Merapi magmas a petrological puzzle. We applied five different geothermobarometers and performed thermodynamic modeling with the MELTS algorithm, and we propose that there are at least three crystallization zones or environments below Merapi. A deep reservoir at about 30 (+/- 3) km depth is suggested by some amphiboles and high-Al clinopyroxenes. Here is where the high-Al basaltic andesites from Merapi are generated

  10. Laser Post-Ionization Mass Spectrometry Analysis of Genesis Solar Wind Collectors

    NASA Astrophysics Data System (ADS)

    Veryovkin, I. V.; Tripa, C. E.; Zinovev, A. V.; Hiller, J. M.; Pellin, M. J.; Burnett, D. S.

    2008-12-01

    The samples returned to Earth by the NASA's Genesis Mission contain a record of the elemental and isotopic abundances of the Solar Wind (SW). This record is formed by the SW ions implanted in the near-surface regions of the Genesis sample collectors, so that the SW material can be distinguished from a terrestrial contamination, which occurred due to the crash landing of the spacecraft Sample Return Capsule. At Argonne National Laboratory, we are conducting analyzes of the Genesis SW collectors using a specially developed Laser Post-Ionization Secondary Neutral Mass Spectrometer (LPI SNMS), SARISA. This approach, based on ion sputtering of a SW collector surface and laser post-ionization of the neutral atoms sputtered from it, has proved to be sensitive, accurate and well suited for the quantitative analysis of the Genesis samples. We will report in this work the abundances of SW Mg and Ca measured with SARISA in two types of SW collector materials, silicon and diamond-like carbon (DLC). These LPI SNMS measurements were conducted in Resonance-Enhanced Multi-Photon Ionization (REMPI) regime using a sputter depth profiling method. In order to make our analyzes quantitative, we used specially prepared standards, made from exactly the same materials as the flown Genesis SW collectors and implanted with known fluencies of Mg and Ca ions. The REMPI analyzes of these standards allowed us to characterize the actual efficiency and detection limits of the SARISA instrument: for Mg, its useful yield peaked at about 20% and detection limits corresponded to < 50 part-per-trillion. We measured concentration vs depth profiles for Mg and Ca in SW collectors (Si and DLC, respectively) and compared them to the corresponding implant standards. One striking feature of the SW implants (compared to the standards) was that maxima of the SW element concentration vs depth profiles were broad, with apparent diffusion of the implanted atoms towards the surface and into the bulk. Since these

  11. Genesis Hypotheses Concerning Putative Rootless Cone Groups in Isidis Planitia, Mars

    NASA Astrophysics Data System (ADS)

    Pithawala, T. M.; Ghent, R. R.

    2008-09-01

    ABSTRACT Introduction Isidis Planitia is one of the many areas on Mars containing thumbprint terrain (TPT), a term coined to reflect the resemblance in Viking images to fingerprints. Other instances occur in Argyre, Hellas, Arcadia Planitia, and Utopia Planitia. The terrain is found where Greeley and Guest (1987) have defined the Hesperian Ridged Plains (Hvr) unit. However, landforms comprising the TPT in Isidis are markedly different in morphology from those in the northern plains. The purpose of this study is to conduct a systematic examination of the TPT in Isidis Planitia using high-resolution imagery, and to propose a hypothesis for its genesis. Northern Plains TPT Morphology: TPT landforms include branching troughs and medial ridges forming whorled lobes and mounds, most with basal scarps or terraces. TPT has been described as consisting of parallel, en echelon, or nested sets of regularly spaced curvilinear ridges or aligned hills [1]. The ridges were estimated to be 0.5-2.5 km wide and 1-40 km long, with a characteristic spacing of 2-6 km. Whorled lobes of TPT are 75-150 km wide, with heights ranging from 10-200 m. Previous work identified 22 areas of TPT, covering 3000- 420,000 km2 in the Northern Plains at elevations between 0 and -2 km. In Utopia, TPT includes branching troughs and medial ridges [5], and TPT is closely associated with troughs in at least 9 other Northern Plains areas [1]. Northern Plains TPT Origin: MOLA topography supports the hypothesis that TPT and associated trough systems in Utopia and Arcadia Planitae are glacial features [1,2,3]. Possible mechanisms include formation of ridges as moraines and troughs as eskers formed by wet-based continental glaciers. The absence of drumlin fields suggests that the glaciers responsible for forming the topography may have been cold-based and thus did not deform the substrate so as to form drumlins [4]. A puzzling characteristic of Mars alleged glacial landscapes is that they are morphologically

  12. The cytochrome P450 genesis locus: the origin and evolution of animal cytochrome P450s

    PubMed Central

    Nelson, David R.; Goldstone, Jared V.; Stegeman, John J.

    2013-01-01

    The neighbourhoods of cytochrome P450 (CYP) genes in deuterostome genomes, as well as those of the cnidarians Nematostella vectensis and Acropora digitifera and the placozoan Trichoplax adhaerens were examined to find clues concerning the evolution of CYP genes in animals. CYP genes created by the 2R whole genome duplications in chordates have been identified. Both microsynteny and macrosynteny were used to identify genes that coexisted near CYP genes in the animal ancestor. We show that all 11 CYP clans began in a common gene environment. The evidence implies the existence of a single locus, which we term the ‘cytochrome P450 genesis locus’, where one progenitor CYP gene duplicated to create a tandem set of genes that were precursors of the 11 animal CYP clans: CYP Clans 2, 3, 4, 7, 19, 20, 26, 46, 51, 74 and mitochondrial. These early CYP genes existed side by side before the origin of cnidarians, possibly with a few additional genes interspersed. The Hox gene cluster, WNT genes, an NK gene cluster and at least one ARF gene were close neighbours to this original CYP locus. According to this evolutionary scenario, the CYP74 clan originated from animals and not from land plants nor from a common ancestor of plants and animals. The CYP7 and CYP19 families that are chordate-specific belong to CYP clans that seem to have originated in the CYP genesis locus as well, even though this requires many gene losses to explain their current distribution. The approach to uncovering the CYP genesis locus overcomes confounding effects because of gene conversion, sequence divergence, gene birth and death, and opens the way to understanding the biodiversity of CYP genes, families and subfamilies, which in animals has been obscured by more than 600 Myr of evolution. PMID:23297357

  13. Reading the meteoroid impact record of the Stardust and Genesis spacecraft

    NASA Astrophysics Data System (ADS)

    Zolensky, M.

    In 1990 a team of dedicated, hardworking scientists labored long and hard to document the micrometeorite and space debris impact record of the Long Duration Exposure Facility (LDEF) (Zolensky M.E. et al., 1995, Advances in Space Research 16, (11) 53-65). The procedures hammered out and perfected for that spacecraft can now be applied to the next two missions to carry micrometeorite impacted hardware to Earth, the Genesis and Stardust spacecraft. Neither of these missions has as its central goal the collection of micrometeorite impact residues. However, both spacecraft were designed to permit the micrometeorite record to be read. The Genesis spacecraft is now collecting solar wind atoms, but it also carries numerous foil surfaces and polished materials that will serve to record the impact record of interplanetary dust particles and beta meteoroids. In fact, this spacecraft will permit our first look at the composition and mineralogy of the latter materials, whose existence was first established by an analysis of the LDEF impact record by Herb Zook. The Stardust spacecraft was designed to catch comet and interstellar dust grains 10 - 100 microns in diameter in silica aerogel. Smaller cometary dust and interplanetary dust particles will be very difficult to find and extract from the aerogel. Thus, polished aluminu m foil strips are exposed between the aerogel panes, which will better record the microparticle impact record. Plans are for the foils and polished surfaces on these spacecraft to be optically scanned soon after Earth return. The LDEF experience tells us to expect that on the order of 10% of the impact features on the Genesis and Stardust spacecraft should contain impactor residues in the form of vapor or melt deposits, and a few percent of the impact features will contain residues retaining mineralogic information. It will take some considerable time to locate and characterize these particular residues, but of course a principal value of returned samples is

  14. Cleaning Genesis Sample Return Canister for Flight: Lessons for Planetary Sample Return

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Hittle, J. D.; Mickelson, E. T.; Stansbery, Eileen K.

    2016-01-01

    Sample return missions require chemical contamination to be minimized and potential sources of contamination to be documented and preserved for future use. Genesis focused on and successfully accomplished the following: - Early involvement provided input to mission design: a) cleanable materials and cleanable design; b) mission operation parameters to minimize contamination during flight. - Established contamination control authority at a high level and developed knowledge and respect for contamination control across all institutions at the working level. - Provided state-of-the-art spacecraft assembly cleanroom facilities for science canister assembly and function testing. Both particulate and airborne molecular contamination was minimized. - Using ultrapure water, cleaned spacecraft components to a very high level. Stainless steel components were cleaned to carbon monolayer levels (10 (sup 15) carbon atoms per square centimeter). - Established long-term curation facility Lessons learned and areas for improvement, include: - Bare aluminum is not a cleanable surface and should not be used for components requiring extreme levels of cleanliness. The problem is formation of oxides during rigorous cleaning. - Representative coupons of relevant spacecraft components (cut from the same block at the same time with identical surface finish and cleaning history) should be acquired, documented and preserved. Genesis experience suggests that creation of these coupons would be facilitated by specification on the engineering component drawings. - Component handling history is critical for interpretation of analytical results on returned samples. This set of relevant documents is not the same as typical documentation for one-way missions and does include data from several institutions, which need to be unified. Dedicated resources need to be provided for acquiring and archiving appropriate documents in one location with easy access for decades. - Dedicated, knowledgeable

  15. Geochronology and isotopic-geochemical characteristics of magmatic complexes of gold-silver ore-magmatic structures in the Chukotka sector of the Russian Arctic coast