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| ocean island basalts from the South Atlantic: Ascension, Bouvet, St. Helena, Gough and Tristan da Cunha...Cunha Barry L. Weaver, David A. Wood, John Tarney and Jean Louis Joron Geological Society, London, Special...ocean island basalts from the South Atlantic: Ascension, Bouvet, St. Helena, Gough and Tristan da Cunha...David A. Wood, John Tarney and Jean Louis Joron S U M M A R Y: Basaltic and hawaiitic lavas from the S...Atlantic Ocean islands of Ascension, Bouvet, St. Helena, Gough and Tristan da Cunha have been analysed for |
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| England Petrology of the Volcanic Rocks of Saint Helena Island, South Atlantic Abstract: Detailed field...of the two deeply eroded shield volcanoes of Saint Helena has permitted a reconstruction of their growth...textural and chemical variations from basic to salic ends of the series. Major oxide contents and a number...of known stratigraphic position. The intermediate and trachytic rocks are believed to be derived from a...processes of crystal fractionation. Volatile transfer and migration of alkali-rich late-crystallizing fluids |
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| ELSEVIER Earth and Planetary Science Letters 171 (1999) 575–589 www.elsevier.com/locate/epsl First...22 July 1999 Abstract Resolving the time–space (and compositional) evolution of volcanism along long-lived...understanding the connection between hotspot volcanism and mantle plumes. 40 Ar=39 Ar ages are reported here...southwest line extending from the vicinity of Saint Helena Island, and also for Circe Seamount. These seamounts...created in a midplate setting and could have formed rapidly (1 Myr). The St. Helena Seamount ages reveal a |
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| Mineralogy and Petrology 9 Springer-Verlag 1990 Geochemistry of highly-undersaturated ocean island basalt...Ocean: Fernando de Noronha and Trindade islands Barry L. Weaver School of Geology and Geophysics, University...de Noronha and Trindade comprise a diverse magmatic series ranging from nephelinites and basanites to...to phonolites and, on Fernando de Noronha, trachytes. All rock types are highly silica undersaturated...Noronha trachytes), and have high abundances of incompatible trace elements and strongly LREE (light |
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| Contributions to Mineralogy and Petrology Contrib. Mineral. Petrol. 66, 9 1 - 104 (1978) 9 by Springer-Verlag...Group Division of igneous rocks into subalkalic and alkalic groups was made first by Iddings (I892)....Harker (1896, 1909). By his thesis, the subalkalic and alkalic groups represent two large branches of igneous...includes rocks ranging from basic to acidic composition and represents a genetic series. The tectonic conditions...subalkalic and alkalic branches were regarded (by mistake) as being characteristic of the Pacific and Atlantic |
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| Earth and Planetary Science Letters, 110 (1992) 121- 131 Elsevier Science Publishers B.V., Amsterdam...rocks from Saint Helena David W. G r a h a m a,b,* Susan E. Humphris a, William J. Jenkins a and Mark D....olivine and clinopyroxene phenocrysts in 7-15 m.y. old basaltic lavas from the island of St. Helena. Magmatic...extraction techniques, including in vacuo crushing, and stepwise heating or fusion of the powders following...following crushing. The inherited 3He/nile ratio at St. Helena is 4.3-5.9 R a. Helium isotope disequilibrium is |
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| 9 by Springer-Verlag 1975 Petrological Aspects and Evolution of the Leucite Bearing Lavas from Bufumbira...Bufumbira, South West Uganda A. K. Ferguson and A. Cundari School of Geology, University of Melbourne, Parkville...by the presence of leucite both as phenocrysts and in the groundmass. Samples studied from the Bufumbira...differentiates through phonolitictephrites to a trachyte and the other differentiates through leucitites to a...are discussed in terms of the coexisting phases and ultramafie inclusions observed in the lavas. Equilibrium |
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| Contributions to Mineralogy and Petrology Contrib Mineral Petrol (1986) 93 :297-311 9 Springer-Verlag...Springer-Verlag 1986 Petrology and evolution of transitional alkalinesub alkaline lavas from Patmos, Dodecanesos...magma mixing and assimilation G. Paul Wyers and Michael Barton Department of Geology and Mineralogy, The...43210, USA Abstract. Petrographic, mineral chemical and whole-rock major oxide data are presented for the...about 7 m.y. ago and range in composition from ne-trachybasalts through hy-trachybasalts and trachyandesites |
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| The Geology of Saint Helena Island Author(s): Reginald A. Daly Source: Proceedings of the American Academy...Academy of Arts and Sciences, Vol. 62, No. 2 (Mar., 1927), pp. 31-92 Published by: American Academy of...that helps scholars, researchers, and students discover, use, and build upon a wide range of content... We use information technology and tools to increase productivity and facilitate new forms of scholarship...digitize, preserve and extend access to Proceedings of the American Academy of Arts and Sciences. http://www |
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| m / l o c a t e / l i t h o s The geochemistry and evolution of Palaeogene phonolites, central Namibia...collectively exhibit a narrow compositional range and represent a single magma system of highly evolved...Na2O, Rb, Th, Zr, Zn, Pb, and REE and very low abundances of MgO, P2O5, Sr and Ba. No mafic rocks are associated...associated with the Aris phonolites and their ultimate petrogenetic origin remains obscure. The more abundant...sanidine (and nepheline) and pyroxene. The behaviour of REE is decoupled from Zr, Nb, and Th in this |
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| Assemblage in a Near-Saturated Hawaiite Janice Knutson and Trevor H. Green School of Earth Sciences, Macquarie...megacrysts and cumulates of olivine, clinopyroxene, orthopyroxene, plagioclase, ilmenite and apatite in...5 15 kb and 0 5% HzO, orthopyroxene was identified in only one run with 2% H20 at 1 040~ C and 6.5 kb...clinopyroxene and Fe-Ti oxide. The early appearance ofplagioclase in the" dry" experimental runs and amphibole...in silica-undersaturated alkali-olivine basalts and these have been interpreted as substantiating experimental |
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| partitioning between olivine and silicate melt: implications for melt structure and calcium content of magmatic...that control calcium partitioning between olivine and melt in a magmatic environment was undertaken using...alumina, alkali and ferrous iron present in the coexisting melt. Oxygen fugacity and temperature are...model describing Ca partitioning between olivine and melt is developed. When applied to natural olivines...melt composition during olivine crystallization and/or to assess whether an olivine is in equilibrium |
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| Contributions to Mineralogy and Petrology Contrib Mineral Petrol (1987) 97:279 291 9 Springer-Verlag1987...fractionation, mixing and assimilation G. Paul Wyers and Michael Barton Department of Geology and Mineralogy, The...OH 43210, USA Abstract. Trace-element and preliminary Sr- and O-isotopic data are reported for a transitional...ne-trachybasalt, hy-trachybasalt, hy-trachyandesite and Q-trachyte. Rb, Sr and Ba contents, as well as K/Rb ratios,...of oceanic islands and those of K-rich alkaline lavas of continental regions and are consistent with |
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| system: mineral chemistry and trace element partitioning between Mg-hastingsite and alkali basaltic melt M...M VICCARO, C FERLITO and R CRISTOFOLINI* Dipartimento di Scienze Geologiche, Università...in the volcanics of the whole Etnean succession and commonly are represented by kaersutites to titanian...been found in lavas and tephra from the 2001 eruption at Mt. Etna. New major (EMPA) and trace element (LAM-ICP/MS)..., AlVI , K and Mg# values, which are higher in Mg-hastingsite than in kaersutite. Ti and Na are lower |
 | Grant, Norman K., Powell, James L., Burkholder, Flora R., Walther, John V., Coleman, Max L. (1976) The isotopic composition of strontium and oxygen in lavas from St. Helena, South Atlantic. Earth and Planetary Science Letters, 31 (2) 209-223 doi:10.1016/0012-821x(76)90213-2 | Journal (article/letter/editorial) |
| Earth and Planetary Science Letters, 31 (1976) 209-223 © Elsevier Scientific Publishing Company, Amsterdam...ISOTOPIC COMPOSITION OF STRONTIUM AND OXYGEN IN LAVAS FROM ST. HELENA, SOUTH ATLANTIC NORMAN K. GRANT,...of Geology and Geophysics, University o f California at Berkeley, Berkeley, Calif. (USA) and MAX L. COLEMAN...Strontium and oxygen isotope measurements on the alkali basalt-trachyte-phonolite suite of St. Helena show...the late-fractionated rocks are enriched in 87Sr and depleted in 180 relative to the older basalts. The |
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| tholeiites (from island arcs), calc-alkali basalts and shoshonites (from volcanic arcs) and within-plate...subdivision of withinplate basalts into ocean island and continental basalts could not however be achieved...with any great success. Gassification of weathered and metamorphosed ocean-floor basalts showed that alteration...numerical and visual methods to lavas of 'unknown' tectonic settings (Archaean greenstones and high-potash...element oxides, SiO2, TiO2, A12O3, FeO, MgO, CaO, Na2O and K2O (the major element 'pattern'), is used extensively |
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| Lineages and Fractionation Trends in Undersaturated Volcanic Rocks from the East Otago Volcanic Province...Province (New Zealand) and Related Rocks by D. s. COOMBS and j . F. G. WILKINSON ABSTRACT The petrology...sodic lavas and shallow intrusives whose compositions range from alkali basalt, basanite, and nephelinite...nephelinite to trachyte and phonolite. A range of relatively potassic volcanic rocks is also developed in the... The degree of undersaturation and ratios such as (FeO+Fe2O3):MgO and K,O:Na,O vary widely in rocks with |
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| mineralogy (chief constituents are sanidine, nepheline and analcime) are recorded from a basanite flow in the...resulting from two immiscible liquids. Petrographic and available experimental data i,tdicate that the globules...(1967) showed experimentally th~lt alkali basalts and even basanites could be derived by fractionation...melting of mantle pyrolite and they cite the frequent occurrence of peridotite and pyroxenite inclusions as...a deep seated origin for the basalts, basanites and nephelinites of the association. Although phonolite |
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| Notes MAZOR E. and ANUERS E. (1967) Primordial gases in the Jodzic howarthto and the origin 1,1 gas-rich...31, 1&l-I&X. MURTHYV. R. and COMPSTOXW. (1965) Rb-Sr ages of chontlrulrs and carbonaceous chontlrikx J...A&on. Inst. Neth. 19, 113. PRICE P. B., RAJAN R. S. and TAMHANEA. S. (1968) The abundance of nuclei heavier...past. Astroph,ys. J. 151, L109L116. REED G. W., JR. and JOVANOV~C S. (1967) Mercury in chondrites. J. Ueophys...Res. 72,2219-%228 RINC+WOODA. E. (1961) Chemical and genetic relationships among meteorites. Geockim. |
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| Carlton Victoria 3053, Australia DISTRIBUTORS USA and Canada Blackwell Scientific Publications Inc PO Box...granted by The Geological Society for libraries and other users registered with the Copyright Clearance...Typeset, printed and bound in Great Britain by William Clowes Limited, Beccles and London Library of...metasomatism--perspective and prospect vii ix 1 MENZIES, M. Alkaline rocks and their inclusions: a window...experimental studies 29 LE Bhs, M. J. Nephelinites and carbonatites 53 TWYMAN, J. D. & GITTINS, J. Alkalic |
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| SYSTEM DIOPSIDE--ALBITE-ANORTHITE SHOHEI BANNO and MASAO YAMASAKI Department of Earth Sciences, Kanazawa...November 18, 1977; revised and accepted June 22, 1978) ABSTRACT Banno, S. and Yamasaki, M., 1979. Behavior...ionic radii capable of substituting for Ca in plagioclase is calculated for the model system diopside--albite--anortbite...assumptions were made on the system. (1) Plagioclase is an ideal solution and diopside has a fixed composition...diopside, albite and anorthite. Trace elements can substitute Ca and Na in the plagioclase "molecule" of |
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| 1975. All ";yhts reserved VOLCANIC ROCK SERIES AND :-:10039 TECTONIC SETTING. Annu. Rev. Earth Planet...CLASSIFICATION OF BASALTS AND THREE MAIN VOLCANIC ROCK SERIES Basalts are the most widespread and abundant type of...of volcanic rock on the earth. Daly (1914) and Bowen (1928) regarded magmas of basaltic composition as...from the same basaltic magma. Andesite, dacite, and rhyolite were regarded as representing residual liquids...alkalic. Thus, Daly and Bowen presumed the uniformity of parental basaltic magmas and the derivation of |
 | Kawabata, Hiroshi, Hanyu, Takeshi, Chang, Qing, Kimura, Jun-Ichi, Nichols, Alexander R. L., Tatsumi, Yoshiyuki (2011) The Petrology and Geochemistry of St. Helena Alkali Basalts: Evaluation of the Oceanic Crust-recycling Model for HIMU OIB. Journal of Petrology, 52 (4) 791-838 doi:10.1093/petrology/egr003 | Journal (article/letter/editorial) |
| 1093/petrology/egr003 The Petrology and Geochemistry of St. Helena Alkali Basalts: Evaluation of the Oceanic...JUN-ICHI KIMURA, ALEXANDER R. L. NICHOLS AND YOSHIYUKI TATSUMI AND TECHNOLOGY (JAMSTEC), YOKOSUKA 237-0061...element, trace element, and petrographic data on alkali basalts from St. Helena, and examine the geochemical...420·5) ocean island basalts. Petrographic and compositional variations in the St. Helena basalts are best...the combined effect of fractional crystallization and accumulation of phenocrysts. Primary melt compositions |
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| Contr. Mineral. and Petrol. 42, 93--108 (1973) 9 by Springer-Verlag 1973 The Primary Geochemistry of...basalts, basanites and nephelinites have undergone only limited crystal fractionation, and that a few may...magmas. Fractionation involves essentially olivine and clinopyroxene; fractionation trends are identified...plotting trace-element abundances against Mg number, and are then extrapolated linearly back into the primary...the three rock types. The nephelinites, basanites and alkali basalts are interpreted as a partial melting |
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| The geology and petrology of Bouvetoya, south Atlantic Ocean PALL IMSLAI~TD, JORGEN G. LARSEN, TORE PRESTVIK...Prestvik, T. & Sigmond, E. M. 1977: The deoiogy and petrology of Bouvet~ya, south Atl;mtic Ocean. Lithos... 213-234, Oslo. ISSN 0024-4937. The Quaternary island Bouvetoya is situated near the triple junction...intermediate and peralkaline silicie rocks ot a transitional rock series are recorded. Major and trace element...element chemistry, model calculations and petrographic observations do not favour a closed sy-~tem fractional |
