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  • SPACE SCIENCES  (3)
  • Geomagnetics  (2)
  • LEIS  (2)
  • Rodinia  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International journal of earth sciences 85 (1996), S. 800-821 
    ISSN: 1437-3262
    Keywords: East Antarctica ; Greenville ; Pan-African ; Rodinia ; Heimefrontfjella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The Heimefrontfjella mountains, Western Dronning Maud Land (East Antarctica), are dominantly composed of Grenville-aged (≈ 1.1 Ga) rocks, which were reworked during the Pan -African orogeny at ≈500 Ma. Three discontinuity-bounded Grenville-aged terranes have been recognized namely (from north to south) the Kottas, Sivorg and Vardeklettane terranes. The terranes contain their own characteristic lithological assemblages, although each is made up of an early supracrustal sequence of metavolcanic and/or metasedimentary gneisses, intruded by various (predominantly granitoid) suites. No older basement upon which the protoliths of these older gneisses were deposited has been recognized. In each terrane the older layered gneisses were intruded by various plutonic suites ranging in age from ≈ 1150 to ≈1000 Ma. The Vardeklettane terrane is characterized by abundant charnockites and two-pyroxene granulite facies parageneses in metabasites, whereas the Sivorg and Kottas terranes were metamorphosed to amphibolite facies grade. P-T estimates show that peak metamorphic conditions changed from ≈600°C at 8 kbar in the south, to ≈700 °C at 4 kbar in the northern Sivorg terrane. Regional greenschist retrogression of high-grade assemblages may be of Pan-African age. The Heimefrontfjella terranes were juxtaposed and pervasively deformed during a complex and protracted period of E-W collision orogenesis in a transpressive regime at ≈ 1.1 Ga. This is manifest as early, gently dipping thrust-related shear fabrics (D1), succeeded by the initiation of an important (D2) steep dextral shear zone (Heimefront shear zone, HSZ), during which the early fabrics and structures were steepened and rotated in an anticlockwise sense. The HSZ is a curvilinear structure which changes from a dextral oblique strike-slip lateral ramp in the north to a steep dip-slip frontal ramp in the south, where it forms the boundary between the Sivorg and Vardeklettane terranes. The Pan-African event is manifested as discrete, low- to medium-temperature ductile to brittle shears (D3) and numerous K/Ar cooling ages.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-879X
    Keywords: Ni/Al2O3 catalysts ; growth mechanism ; hydrogenation of toluene ; surface characterization ; ALE ; LEIS ; ISS ; XPS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A series of Ni/Al2O3 catalysts prepared from vapor phase by the atomic layer epitaxy (ALE) technique have been studied. A model is proposed for the growth mechanism of nickel in its oxidic form on alumina, from sequences of treatments with Ni(acac)2 and air. In the study activity measurements were combined with surface analysis by LEIS and XPS. During the first preparation sequence (〈 5 wt% Ni) atomically dispersed nickel is obtained on the alumina support. The nickel atoms are catalytically inactive, but act as nuclei for the growth of the catalytically active Ni-species during the subsequent preparation sequences. The highest utilization of nickel atoms in the hydrogenation of toluene was obtained when the nickel nuclei were covered with one layer of active nickel species.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-879X
    Keywords: Pt-Pd/alumina ; combustion catalyst ; hydrothermal treatment ; xylene oxidation ; light-off temperature ; TEM/STEM/EDS ; LEIS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two Pt/Pd catalysts on cordierite monoliths were prepared by impregnating two differently treated alumina washcoats with 10 μmol [Pt+Pd] per gram catalyst in the atomic ratio Pt/Pd=4.0. Both washcoats were first thermally treated, calcined, for 2 h at 550 °C in air and one of them was additionally treated, hydrothermally, in 100% steam for 2 h at 814 °C. The hydrothermally treated catalyst was more active for complete oxidation of xylene in air: its light-off temperature was 232 °C, compared to 259 °C for the sample calcined only. To explain this higher activity, both catalysts were characterized by BET surface area, pore-size distribution, hydrogen chemisorption, X-ray diffraction, TEM/STEM/EDS and low-energy ion scattering spectroscopy (LEIS). The catalyst with a hydrothermally treated washcoat had 30% lower surface area, larger alumina crystal size, higher degree of crystallization of alumina and larger average catalyst pore size (11 nm vs. 6 nm), than the one with the washcoat, treated only thermally. The LEIS results indicated a surface enrichment of Pd on both catalysts. The Pt signal in LEIS was higher for the hydrothermally treated sample.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0016-7835
    Keywords: Key words East Antarctica ; Greenville ; Pan-African ; Rodinia ; Heimefrontfjella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The Heimefrontfjella mountains, Western Dronning Maud Land (East Antarctica), are dominantly composed of Grenville-aged (∼1.1 Ga) rocks, which were reworked during the Pan -African orogeny at ∼500 Ma. Three discontinuity-bounded Grenville-aged terranes have been recognized namely (from north to south) the Kottas, Sivorg and Vardeklettane terranes. The terranes contain their own characteristic lithological assemblages, although each is made up of an early supracrustal sequence of metavolcanic and/or metasedimentary gneisses, intruded by various (predominantly granitoid) suites. No older basement upon which the protoliths of these older gneisses were deposited has been recognized. In each terrane the older layered gneisses were intruded by various plutonic suites ranging in age from ∼1150 to ∼1000 Ma. The Vardeklettane terrane is characterized by abundant charnockites and two-pyroxene granulite facies parageneses in metabasites, whereas the Sivorg and Kottas terranes were metamorphosed to amphibolite facies grade. P–T estimates show that peak metamorphic conditions changed from ∼600  °C at 8 kbar in the south, to ∼700  °C at 4 kbar in the northern Sivorg terrane. Regional greenschist retrogression of high-grade assemblages may be of Pan-African age. The Heimefrontfjella terranes were juxtaposed and pervasively deformed during a complex and protracted period of E–W collision orogenesis in a transpressive regime at ∼1.1 Ga. This is manifest as early, gently dipping thrust-related shear fabrics (D1), succeeded by the initiation of an important (D2) steep dextral shear zone (Heimefront shear zone, HSZ), during which the early fabrics and structures were steepened and rotated in an anticlockwise sense. The HSZ is a curvilinear structure which changes from a dextral oblique strike-slip lateral ramp in the north to a steep dip-slip frontal ramp in the south, where it forms the boundary between the Sivorg and Vardeklettane terranes. The Pan-African event is manifested as discrete, low- to medium-temperature ductile to brittle shears (D3) and numerous K/Ar cooling ages.
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  • 5
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    Unknown
    Academic Press
    In:  London, Academic Press, vol. 558, no. XVI:, pp. 1-14, (ISBN 3-9808493-1-7)
    Publication Date: 1987
    Keywords: Textbook of geophysics ; Geomagnetics ; Applied geophysics
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  • 6
    facet.materialart.
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    Academic
    In:  San Diego, Calif., Academic, vol. 558, no. XVI:, pp. 1-14, (ISBN 3-9808493-1-7)
    Publication Date: 1991
    Keywords: Geomagnetics ; Textbook of geophysics
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  • 7
    Publication Date: 2011-08-16
    Description: Analytical data have been obtained for Co, Sc, Hf, Zn, Cr, Ga, Rb, Cs, Ni, major elements, and rare earth elements in eight samples from boulder 1. The data for trace elements were obtained by radiochemical neutron activation analysis. Major elements, except Na and Mn, were obtained by atomic absorption spectral photometry. Values for Na and Mn were obtained by neutron activation analysis of the same powder that was later dissolved to provide the atomic absorption analyses.
    Keywords: SPACE SCIENCES
    Type: Smithsonian Astrophys. Obs. Interdisciplinary Studies of Samples from Boulder 1, Sta. 2, Apollo 17, Vol. 1; p 121-129
    Format: text
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  • 8
    Publication Date: 2019-06-27
    Description: The results of the analysis by neutron activation of six samples from the Luna 20 mission and one sample of less than 1 mm fines from Apollo 16 are reported. The concentrations of the rare-earth elements (REE) in the samples of fines from Luna 20 and Apollo 16 are less than those found for corresponding materials from the mare areas but a negative Eu anomaly is still present. The concentrations of the REE in fines from Luna 20 are only about two-thirds as great as in the sample of Apollo 16 fines, but the concentration of Co, Sc and Cr are greater by factors ranging from 1.5 to 2.3.
    Keywords: SPACE SCIENCES
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  • 9
    Publication Date: 2019-07-13
    Description: Analyses for major elements, REE, Co, Cr, Cs, Ga, Hf, Ni, Rb, Sc, and Zn have been done on samples of Apollo 16 rocks 60025, 60335, 64455, 65015, 67075, and 67629 and on fines 60601, 61221, 61241, 64501, 65701, 67601, and 69941. FeO, Na2O, REE, Co, Cr, Hf, and Sc have been determined in four 4-5 mg chips from 65015 and 20 individual, 2.5-9.5 mg fragments from 65702. It appears that trace element characteristics of small fragments are similar to those of larger rocks. No simple mixing relationship was found among KREEP basalts, VHA basalts, anorthosites, fines, and meteorites. Balances could not be simultaneously achieved for Al2O3 and LIL elements, using analyzed samples as end members for mixing models. Most samples analyzed have negative Eu anomalies, in contrast to the positive anomalies expected for plagioclase cumulates. Most samples may be derived from LIL-rich liquids that flowed into highland valleys.
    Keywords: SPACE SCIENCES
    Type: Lunar Science Conference; Mar 05, 1973 - Mar 08, 1973; Houston, TX
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