Search Results - (Author, Cooperation:S. Foley)

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  1. 1
    R. Preece ; J. M. Burgess ; A. von Kienlin ; P. N. Bhat ; M. S. Briggs ; D. Byrne ; V. Chaplin ; W. Cleveland ; A. C. Collazzi ; V. Connaughton ; A. Diekmann ; G. Fitzpatrick ; S. Foley ; M. Gibby ; M. Giles ; A. Goldstein ; J. Greiner ; D. Gruber ; P. Jenke ; R. M. Kippen ; C. Kouveliotou ; S. McBreen ; C. Meegan ; W. S. Paciesas ; V. Pelassa ; D. Tierney ; A. J. van der Horst ; C. Wilson-Hodge ; S. Xiong ; G. Younes ; H. F. Yu ; M. Ackermann ; M. Ajello ; M. Axelsson ; L. Baldini ; G. Barbiellini ; M. G. Baring ; D. Bastieri ; R. Bellazzini ; E. Bissaldi ; E. Bonamente ; J. Bregeon ; M. Brigida ; P. Bruel ; R. Buehler ; S. Buson ; G. A. Caliandro ; R. A. Cameron ; P. A. Caraveo ; C. Cecchi ; E. Charles ; A. Chekhtman ; J. Chiang ; G. Chiaro ; S. Ciprini ; R. Claus ; J. Cohen-Tanugi ; L. R. Cominsky ; J. Conrad ; F. D'Ammando ; A. de Angelis ; F. de Palma ; C. D. Dermer ; R. Desiante ; S. W. Digel ; L. Di Venere ; P. S. Drell ; A. Drlica-Wagner ; C. Favuzzi ; A. Franckowiak ; Y. Fukazawa ; P. Fusco ; F. Gargano ; N. Gehrels ; S. Germani ; N. Giglietto ; F. Giordano ; M. Giroletti ; G. Godfrey ; J. Granot ; I. A. Grenier ; S. Guiriec ; D. Hadasch ; Y. Hanabata ; A. K. Harding ; M. Hayashida ; S. Iyyani ; T. Jogler ; G. Johannesson ; T. Kawano ; J. Knodlseder ; D. Kocevski ; M. Kuss ; J. Lande ; J. Larsson ; S. Larsson ; L. Latronico ; F. Longo ; F. Loparco ; M. N. Lovellette ; P. Lubrano ; M. Mayer ; M. N. Mazziotta ; P. F. Michelson ; T. Mizuno ; M. E. Monzani ; E. Moretti ; A. Morselli ; S. Murgia ; R. Nemmen ; E. Nuss ; T. Nymark ; M. Ohno ; T. Ohsugi ; A. Okumura ; N. Omodei ; M. Orienti ; D. Paneque ; J. S. Perkins ; M. Pesce-Rollins ; F. Piron ; G. Pivato ; T. A. Porter ; J. L. Racusin ; S. Raino ; R. Rando ; M. Razzano ; S. Razzaque ; A. Reimer ; O. Reimer ; S. Ritz ; M. Roth ; F. Ryde ; A. Sartori ; J. D. Scargle ; A. Schulz ; C. Sgro ; E. J. Siskind ; G. Spandre ; P. Spinelli ; D. J. Suson ; H. Tajima ; H. Takahashi ; J. G. Thayer ; J. B. Thayer ; L. Tibaldo ; M. Tinivella ; D. F. Torres ; G. Tosti ; E. Troja ; T. L. Usher ; J. Vandenbroucke ; V. Vasileiou ; G. Vianello ; V. Vitale ; M. Werner ; B. L. Winer ; K. S. Wood ; S. Zhu
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-11-23
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    E. Harris ; B. Sinha ; D. van Pinxteren ; A. Tilgner ; K. W. Fomba ; J. Schneider ; A. Roth ; T. Gnauk ; B. Fahlbusch ; S. Mertes ; T. Lee ; J. Collett ; S. Foley ; S. Borrmann ; P. Hoppe ; H. Herrmann
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-05-11
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Aerosols ; Atmosphere/*chemistry ; Catalysis ; *Climate ; *Dust ; Minerals/chemistry ; Oxidation-Reduction ; Sulfur Dioxide/*chemistry ; Transition Elements
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    M. Ackermann ; M. Ajello ; K. Asano ; W. B. Atwood ; M. Axelsson ; L. Baldini ; J. Ballet ; G. Barbiellini ; M. G. Baring ; D. Bastieri ; K. Bechtol ; R. Bellazzini ; E. Bissaldi ; E. Bonamente ; J. Bregeon ; M. Brigida ; P. Bruel ; R. Buehler ; J. M. Burgess ; S. Buson ; G. A. Caliandro ; R. A. Cameron ; P. A. Caraveo ; C. Cecchi ; V. Chaplin ; E. Charles ; A. Chekhtman ; C. C. Cheung ; J. Chiang ; G. Chiaro ; S. Ciprini ; R. Claus ; W. Cleveland ; J. Cohen-Tanugi ; A. Collazzi ; L. R. Cominsky ; V. Connaughton ; J. Conrad ; S. Cutini ; F. D'Ammando ; A. de Angelis ; M. DeKlotz ; F. de Palma ; C. D. Dermer ; R. Desiante ; A. Diekmann ; L. Di Venere ; P. S. Drell ; A. Drlica-Wagner ; C. Favuzzi ; S. J. Fegan ; E. C. Ferrara ; J. Finke ; G. Fitzpatrick ; W. B. Focke ; A. Franckowiak ; Y. Fukazawa ; S. Funk ; P. Fusco ; F. Gargano ; N. Gehrels ; S. Germani ; M. Gibby ; N. Giglietto ; M. Giles ; F. Giordano ; M. Giroletti ; G. Godfrey ; J. Granot ; I. A. Grenier ; J. E. Grove ; D. Gruber ; S. Guiriec ; D. Hadasch ; Y. Hanabata ; A. K. Harding ; M. Hayashida ; E. Hays ; D. Horan ; R. E. Hughes ; Y. Inoue ; T. Jogler ; G. Johannesson ; W. N. Johnson ; T. Kawano ; J. Knodlseder ; D. Kocevski ; M. Kuss ; J. Lande ; S. Larsson ; L. Latronico ; F. Longo ; F. Loparco ; M. N. Lovellette ; P. Lubrano ; M. Mayer ; M. N. Mazziotta ; J. E. McEnery ; P. F. Michelson ; T. Mizuno ; A. A. Moiseev ; M. E. Monzani ; E. Moretti ; A. Morselli ; I. V. Moskalenko ; S. Murgia ; R. Nemmen ; E. Nuss ; M. Ohno ; T. Ohsugi ; A. Okumura ; N. Omodei ; M. Orienti ; D. Paneque ; V. Pelassa ; J. S. Perkins ; M. Pesce-Rollins ; V. Petrosian ; F. Piron ; G. Pivato ; T. A. Porter ; J. L. Racusin ; S. Raino ; R. Rando ; M. Razzano ; S. Razzaque ; A. Reimer ; O. Reimer ; S. Ritz ; M. Roth ; F. Ryde ; A. Sartori ; P. M. Parkinson ; J. D. Scargle ; A. Schulz ; C. Sgro ; E. J. Siskind ; E. Sonbas ; G. Spandre ; P. Spinelli ; H. Tajima ; H. Takahashi ; J. G. Thayer ; J. B. Thayer ; D. J. Thompson ; L. Tibaldo ; M. Tinivella ; D. F. Torres ; G. Tosti ; E. Troja ; T. L. Usher ; J. Vandenbroucke ; V. Vasileiou ; G. Vianello ; V. Vitale ; B. L. Winer ; K. S. Wood ; R. Yamazaki ; G. Younes ; H. F. Yu ; S. J. Zhu ; P. N. Bhat ; M. S. Briggs ; D. Byrne ; S. Foley ; A. Goldstein ; P. Jenke ; R. M. Kippen ; C. Kouveliotou ; S. McBreen ; C. Meegan ; W. S. Paciesas ; R. Preece ; A. Rau ; D. Tierney ; A. J. van der Horst ; A. von Kienlin ; C. Wilson-Hodge ; S. Xiong ; G. Cusumano ; V. La Parola ; J. R. Cummings
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-11-23
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Staff View
    Publication Date:
    2018-08-02
    Publisher:
    Cold Spring Harbor Laboratory Press
    Print ISSN:
    0890-9369
    Topics:
    Biology
    Published by:
    http://www.cshlpress.com/

    Latest Papers from Table of Contents or Articles in Press
  5. 5
    DePaola, P. F. ; Soparkar, P. ; Foley, S. ; Bookstein, F. ; Bakhos, Y.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1977
    Staff View
    ISSN:
    1600-0528
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    abstract A double-blind clinical trial was conducted in a non-fluoridated community to determine the effect on enamel fluoride and caries experience of daily rinsing in school with 1,000 parts/106 solutions of ammonium fluoride or sodium fluoride at pH 4.4. Subjects were 10- to 12-year-old children (n ≅ 200/group at baseline), about one-half of whom reported the usage of fluoride supplements. Dental caries (DFS index) and enamel fluoride (in vivo biopsy) were evaluated at baseline, 12 months, and 24 months. Supplement users had higher enamel fluoride levels and less caries experience initially, as well as generally lower caries increments over the study. In year 1, the overall caries reductions (supplement users and non-users combined) were 23% (ammonium fluoride) and 33% (sodium fluoride), P 〈 0.01. For year 2, treatment effects were significantly greater: 54 % (ammonium fluoride) and 47 % (sodium fluoride). In newly erupted teeth, the effects of the ammonium fluoride (70 % DFS reduction) was significantly greater (P = 0.013) than that of the sodium fluoride (48 % DFS reduction). Enamel fluoride levels at the end of 2 years were 3,124 parts/106 (ammonium fluoride), 2,771 parts/106 (sodium fluoride), and 2,603 parts/106 (placebo), P= 0.025.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1600-0528.1977.tb01611.x

    Articles: DFG German National Licenses
  6. 6
    Foley, S. F. ; Petibon, C. M. ; Jenner, G. A. ; Kjarsgaard, B. A.

    Oxford UK : Blackwell Publishing Ltd
    Published 2001
    Staff View
    ISSN:
    1365-3121
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Geosciences
    Notes:
    Clinopyroxene/melt pairs in strongly potassic silicate and carbonatite melts exhibit unusually high U/Th partitioning ratios of ˜ 3 and ˜ 2, respectively. These values are much higher than those found for aluminous clinopyroxenes in peridotite, and have the potential to cause significant (230Th)/(238U) isotope enrichment in volcanics. The potassic silicate (lamproite) and carbonatite melts correspond closely to the main agents of mantle metasomatism, indicating that clinopyroxene in metasomatized regions of the mantle may greatly affect U/Th disequilibria. Recycling of alkali pyroxenite veins in the oceanic lithosphere formed by solidification of melt in the extremities of the MORB melting region presents an alternative to eclogite recycling in MORB and OIB genesis.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1046/j.1365-3121.2001.00323.x

    Articles: DFG German National Licenses
  7. 7
    Super, M. ; Gillies, S. D. ; Foley, S. ; Sastry, K. ; Schweinle, J.-E. ; Silverman, V. J. ; Ezekowitz, R. A. B.

    [s.l.] : Nature Publishing Group
    Published 1992
    Staff View
    ISSN:
    1546-1718
    Source:
    Nature Archives 1869 - 2009
    Topics:
    Biology
    Medicine
    Notes:
    [Auszug] Human mannose binding protein (MBP) is a C–type serum lectin involved in first–line host defense against a variety of bacterial, fungal and viral pathogens. Recently an association was found between low levels of serum MBP and an increased frequency of recurrent infections in infants. A ...
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1038/ng0992-50

    Articles: DFG German National Licenses
  8. 8
    Foley, S.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0308-521X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0308-521X(87)90042-4

    Articles: DFG German National Licenses
  9. 9
    Andronikov, A. V. ; Foley, S. F. ; Beliatsky, B. V.
    Springer
    Published 1998
    Staff View
    ISSN:
    1438-1168
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geosciences
    Description / Table of Contents:
    Zusammenfassung Sm-Nd- und Rb-Sr-Isotope wurden in einer Abfolge von K-reichen OlivinTrachybasalten im Manning Massiv in den nördlichen Prince Charles Mountains, Ost-Antarktis, untersucht. Proben wurden systematisch von mehreren sich überlagernden Lavaströmen genommen, die Mächtigkeiten von 3,5 bis 6,5 m erreichen und dem Lambert-Amery Rift zugeordnet werden. Nd-Sr Isotopenzusammensetzung der Vulkanite sind ähnlich wie in Iherzolithischen Mantelxenolithen aus alkalischen Ultramafiten der Jetty Halbinsel. Allerdings deuten die Spurenelementgehalte sowie die Spurenelementverteilungen auf die Anwesenheit von Apatit, Amphibol, Ilmenit und Perowskit in der Quellenregionhin. Nd-Sr Isotope der Trachybasalte (143Nd/144Nd= 0.512026–0.512269;87Sr/86Sr = 0.707765–0.708046) weisen auf eine angereicherte Mantelzusammensetzung hin. Für die hier gefundenen Werte wird ein Mischungsmodell zwischen einem Peridotit-Nebengestein ähnlich wie in den Jetty Halbinsel Xenolithen und einer Schmelze vorgeschlagen, die aus ultramafischen Gängen innerhalb der Lithosphäre stammte. Die Kombination aus Isochronenalter und Modellalter der Vulkanite und der Xenolithe zeigt, daß nach der Bildung vor 1.2 Ga die Lithosphäre zwei Anreicherungsereignisse vor 0.9-1.0 Ga und 0.6 Ga erfahren hatte. Trotz der hohen Variation der143Nd/144Nd Verhältnisse ergeben sich für die unteren Lavaströme höhere Werte, während die oberen Bereiche an143Nd verarmt sind. Dies kann auf eine stetige Abnahme des Gang/Peridotit Verhältnisses von 35% auf 10% zurückgeführt werden, das auf eine fortschreitende Aufheizung der Quellenregion hinweist. Die Variation im143Nd/144Nd System wird aber nicht von einem Anstieg des87Sr/86Sr Verhältnisses begleitet, was mit ähnlichen Werten sowohl für die Gänge als auch für den angrenzenden Peridotit erklärt werden kann: das Nebengestein bestand aus einem angereicherten Peridotit, während die Gänge hauptsächlich aus Klinopyroxen und Amphibol zusammengesetzt waren. SEE-reiche Phasen wie Apatit und Perowskit kamen in so geringen Mengen vor, daß die Gesamtzusammensetzung der Gänge hohe Sr/Nd-Verhältnisse hatte. Rb-Sr Altersbestimmungen an Gesamtgesteinen der Manning Massiv-Vulkanite ergeben eine scheinbare Isochrone von 40±1.2 Ma (ISr = 0.70762), obwohl diese Altersinformation vermutlich durch die Mischungsprozesse während des partiellen Schmelzens verfälscht ist.
    Notes:
    Summary Rb-Sr and Sm-Nd isotopic investigations have been carried out on samples forming a sequence from the bottom to the top of a suite of K-rich olivine trachybasalts from the Manning Massif in the northern Prince Charles Mountains, East Antarctica. Several separate flows, each 3.5-6.5 m thick, occur as individual small outcrops and are related to the Lambert-Amery rift. Nd-Sr isotopic features of the volcanics are similar to those for lherzolite xenoliths from the Mesozoic alkaline ultramafic rocks of the adjacent Jetty Peninsula area, but the trace element abundances and patterns are consistent with the occurrence of minor phases such as apatite, amphibole, ilmenite and perovskite in the source region. According to Nd-Sr isotopic characteristics (143Nd/144Nd = 0.512026-0.512269;87Sr/86Sr = 0.707765-0.708046), the trachybasalts were generated from an enriched mantle source. These features are suggested here to result from isotopic mixing between peridotite wall-rocks similar to the Jetty Peninsula xenolith samples and melts derived from ultramafic veins in the lithosphere. A synthesis from isochron and model ages on volcanics and xenoliths indicates formation of the lithosphere at about 1.2 Ga, followed by two episodes of subsequent enrichment at 0.91.0 Ga and ca. 0.6 Ga. The143Nd/144Nd values for the volcanics show a wide range, but are more enriched for the bottom part of the suite, becoming more depleted towards the top. This may be explained by a steadily decreasing vein/wall-rock ratio from 35% to 10% due to progressive heating of the source region. This variation in ENd is not accompanied by a corresponding increase in87Sr/86Sr, which constrains both vein and wall-rock characteristics quite closely: the wall-rock was an enriched peridotite, whereas the vein assemblage comprised dominantly clinopyroxene and amphibole with a lesser, but essential, amount of phlogopite. REE-rich accessory phases such as apatite and perovskite were present in the vein, but were rare, so that the vein as a whole had high Sr/Nd. Rb-Sr age determination on Manning Massif bulk rocks gives an apparent isochron age of 40±1.2 Ma (ISr = 0.70762), although the age is probably falsified by the mixing processes during melting.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01164153

    Articles: DFG German National Licenses
  10. 10
    Foley, S. F.
    Springer
    Published 1985
    Staff View
    ISSN:
    1438-1168
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geosciences
    Description / Table of Contents:
    Zusammenfassung Die Olivin-Leuzitite vom Gaussberg Vulkan, Antarktis, gehören zu den primären Gliedern der Lamproit-Gruppe der ultra-kalireichen Gesteine. Sie sind reich an Glas, weisen Mg-Werte um 70 auf, und führen Spinell-Lherzolith Xenolithe. Die Liquidus-Phasengleichgewichte bei Atmosphärendruck unter kontrollierten Sauerstoff-Partialdruckbedingungen wurden untersucht. Um Chromit als Liquidusphase zu stabilisieren, war es erforderlich, Cr2O3 zu den experimentellen Zusammensetzungen hinzuzufügen, obwohl Chromspinell als Einschluß in Olivin in den Ausgangsgesteinen auftritt; dies deutet eine Spinell-Franktionierung an. Die Resultate zeigten, daß diefO2-Bedingungen bei der Kristallisation durch das Fe3+-Verhältnis (100 Fe3+/(Fe3++Fe2+)) im Spinell, durch den Fe3+-Gehalt im Leuzit, und durch den Mg-Wert (100 mg/(Mg+Fe2+)) im Olivin charakterisiert sind. Die Liquidusphasen der Gaussberg Gesteine kristallisierten beifO2-Bedingungen etwas unterhalb NNO. Die Anwendung der Resultate auf andere Lamproite zeigt, daß diese unter Sauerstoff-Partialdruckbedingungen kristallisierten, die von oberhalb NNO (Leucite Hills) bis etwa MW (West Kimberley und die Spanish Fortunites) variierten. Der Gaussberg Olivin-Leuzitit enthält Leuzitkristalle mit deutlicher Zonierung; die Kernbereiche sind arm an dreiwertigem Eisen, während die Randzonen deutlich an Fe3+ angereichert sind. Dies weist auf eine Oxidation des Magmas während der Platznahme hin. Das Fe3+-Verhältnis der Spinelle ist sehr empfindlich gegenüber Änderungen des Sauerstoff-Partialdruckes; da einige lamproitische Magmen Diamanten führen, könnte sich dieses als ein sinnvoller Indikator für eine mögliche Diamantführung erweisen. Die Überlebensfähigkeit von Diamanten in lamproitischen Gesteinen wird sehr stark abhängig sein vonfO2: Magmen, die die Oberfläche unterfO2-Bedingungen entsprechend NNO oder darüber erreichten, werden keine Diamanten mehr erhalten.
    Notes:
    Summary Olivine leucitites from the Gaussberg volcano, Antarctica are primitive members of the lamproite group of ultrapotassic rocks. They are glass rich, have an Mg number of around 70, and carry spinel lherzolite xenoliths. Liquidus phase fields and compositions were studied experimentally at atmospheric pressure with controlled oxygen fugacities. Chrome-spinels occur as inclusions in olivines in the natural rock, but it was necessary to add Cr2O3 to the experiments to stabilize spinels at the liquidus, indicating that some fractionation of spinel has almost certainly occurred. Experimental results show thatfO2 conditions of crystallization can be characterized by ferric value (100 Fe3+/(Fe3++Fe2+)) of spinel, ferric iron content of leucite, and Mg-number (100 Mg/(Mg+Fe2+)) of olivine. The results demonstrate that the liquidus phases of the Gaussberg rocks crystallized atfO2 slightly below that of the NNO buffer. Application of the results to other lamproites indicates that they began to crystallize at oxygen fugacities varying from well above NNO (Leucite Hills) to around MW (West Kimberley and the Spanish fortunites). The Gaussberg olivine leucitite contains leucite cores poor in ferric iron with rims richer in ferric iron, indicating oxidation during emplacement. The ferric value of spinel is very sensitive to changes in oxygen fugacity and recognizing that some lamproitic magmas are known to contain diamonds, it may prove to be useful as a ‘diamond survival indicator’. The preservation of diamonds in lamproitic rocks will depend critically onfO2: diamonds are not likely to be preserved in rocks which reach the surface as liquids atfO2 near NNO or above.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01082963

    Articles: DFG German National Licenses
  11. 11
    Zinngrebe, E. ; Foley, S. F.
    Springer
    Published 1995
    Staff View
    ISSN:
    1432-0967
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geosciences
    Notes:
    Abstract  We have investigated new samples from the Gees mantle xenolith suite (West Eifel), for which metasomatism by carbonatite melt has been suggested. The major metasomatic change is transformation of harzburgites into phlogopite-rich wehrlites. Silicate glasses are associated with all stages of transformation, and can be resolved into two major groups: a strongly undersaturated alkaline basanite similar to the host magma which infiltrated the xenoliths during ascent, and Si-Al-enriched, variably alkaline glass present exclusively within the xenoliths. Si-Al-rich glasses (up to 72 wt% SiO2 when associated with orthopyroxene (Opx) are usually interpreted in mantle xenoliths as products of decompressional breakdown of hydrous phases like amphibole. In the Gees suite, however, amphibole is not present, nor can the glass be related to phlogopite breakdown. The Si-Al-rich glass is compositionally similar to glasses occurring in many other xenolith suites including those related to carbonatite metasomatism. Petrographically the silicate glass is intimately associated with the metasomatic reactions in Gees, mainly conversion of harzburgite orthopyroxene to olivine + clinopyroxene. Both phases crystallize as microlites from the glass. The chemical composition of the Si-Al-enriched glass shows that it cannot be derived from decompressional melting of the Gees xenoliths, but must have been present prior to their entrainment in the host magma. Simple mass-balance calculations, based on modal analyses, yield a possible composition of the melt prior to ascent of the xenoliths, during which glass + microlite patches were modified by dissolution of olivine, orthopyroxene and spinel. This parental melt is a calc-alkaline andesite (55–60 wt% SiO2), characterized by high Al2O3 (ca. 18 wt%). The obtained composition is very similar to high-alumina, calc-alkaline melts that should form by AFC-type reactions between basalt and harzburgite wall rock according to the model of Kelemen (1990). Thus, we suggest that the Si-Al-enriched glasses of Gees, and possibly of other suites as well, are remnants of upper mantle hybrid melts, and that the Gees suite was metasomatized by silicate and not carbonatite melts. High-Mg, high-Ca composition of metasomatic olivine and clinopyroxene in mantle xenoliths have been explained by carbonatite metasomatism. As these features are also present in the Gees suite, we have calculated the equilibrium Ca contents of olivine and clinopyroxene using the QUI1F thermodynamical model, to show that they are a simple function of silica activity. High-Ca compositions are attained at low a SiO2 and can thus be produced during metasomatism by any melt that is Opx-undersaturated, irrespective of whether it is a carbonatite or a silicate melt. Such low a SiO2 is recorded by the microlites in the Gees Si-Al-rich glasses. Our results imply that xenolith suites cannot confidently be related to carbonatite metasomatism if the significance of silicate glasses, when present, is not investigated.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s004100050114

    Articles: DFG German National Licenses
  12. 12
    Staff View
    ISSN:
    1432-0967
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Geosciences
    Notes:
    Abstract New experimental amphibole/melt partition coefficients from a variety of geologically relevant amphibole (pargasite, kaersutite, and K-richterite) and melt compositions obtained under conditions of interest to upper-mantle studies are combined with the results of X-ray single-crystal structure refinement. The ideal cation radii (r0), calculated using the lattice-site elastic-strain model of Blundy and Wood (1994) under the hypothesis of complete REE (rare earth elements) ordering at [8]M4, mostly differ significantly from those obtained from both the structure refinement and the ionic radius of [8]Ca2+. Heavier REE may also strongly deviate from the parabolic trends defined by the other REE. On the basis of the crystal-chemical knowledge of major-element site-preference in amphibole and the occurrence of two sites with different co-ordination within the M4 cavity (M4 for Ca and Na, M4′ for Fe2+ and Mg), we propose a new model for REE incorporation. LREE order at the [8]M4 site, whereas HREE prefer the M4′ site with lower co-ordination in amphiboles with a significant cummingtonite component, and may also enter the M2 octahedron, at least in richterite. This more complex model is consistent with the observed Amph/LD, and drops the usual assumption that REE behave as a homogeneous group and order at the M4 site. The availability of multiple crystal-chemical mechanisms for REE3+ incorporation explains why measured and estimated Amph/LDHREE may differ by up to one order of magnitude. When REE enter two different sites within the same cavity, a fit performed on the basis of a single curve may appear correct, but the values obtained for r0 are biased towards those of the dominant site, and the Young's modulus is underestimated. When REE are incorporated in multiple sites in different cavities, the observed pattern cannot be reduced to a single curve, and the partition coefficients of heavy REE would be strongly underestimated by a single-site fit. The simplistic assumption that REE occupy a single site within the amphibole structure can thus substantially bias predictive models based on the elastic-strain theory. Our combined approach allows linkage between fine-scale site preference and the macroscopic properties of minerals and provides more reliable predictive models for mineral/melt partitioning. After the possible site-assignments have been identified, the shape of the Onuma curves constructed from accurately determined Amph/LDREE now allows the active mechanisms for REE incorporation in amphiboles to be recognised even where site populations are not available. The REE preference for polyhedra with smaller size and lower co-ordination than those occupied by Ca invalidates the general idea that Ca acts as a “carrier” for REE.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s004100050580

    Articles: DFG German National Licenses
  13. 13
    Daniel Patrick Foley, S. J.
    Springer
    Published 1967
    Staff View
    ISSN:
    1573-6571
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Theology and Religious Studies
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01533392

    Articles: DFG German National Licenses