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Showing 1 to 20 of 98 for “"Clinopyroxene"”.
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Paleocene Turbidite Deposition in the Central American Seaway (NW Costa Rica): Geochemical Analysis and Provenance of Detrital Spinel and Clinopyroxene
… spectrometry for major elements of detrital clinopyroxene and spinel grains, (iii) trace element analysis through laser ablation of single detrital clinopyroxene grains, and (iv) comparative analysis of the different potential source rocks to clearly identify the most likely sediment sources. …
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Timing and Source of Alkali Enrichment at Mt. Etna, Sicily: Constraints from Clinopyroxene Geobarometry and In Situ SR Isotope Data
… as the timing and source of alkali-enrichment, clinopyroxene from ten samples erupted between 1329 and 2004 was targeted for <em>in situ</em> textural, major element and Sr isotope analysis. Clinopyroxene disequilibrium textures paired with increased Mg# values imply recharge/mixing at work …
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An ion microprobe study of trace element partitioning between clinopyroxene and liquid in the diopside (CaMgSi2O6) - albite (NaAlSi3O8) - anorthite (CaAl2Si2O8) system
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1981.
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Studies of Magmatism by Trace Element Partitioning Between Clinopyroxene and Silicate Melt, Uranium-Series Disequilibria in Lavas From Subduction Zones, and Non-Traditional Stable Isotopes
Finally, in chapter 5, I report results of Fe-Mg isotopic analyses of a thermal migration experiment. Significant mass-dependent Fe-Mg isotopic fractionations occur in the melt-present portion of the experiment. I conclude that the positive co-variation of Fe-Mg isotopes could be an important …
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The geochemistry of a suite of eclogite xenoliths from the Rietfontein Kimberlite, South Africa
… and other off-craton localities. Garnet, clinopyroxene, accessory and secondary minerals were analysed for major element compositions using electron microprobe techniques and garnet and clinopyroxene trace element compositions were determined by Laser Ablation Inductively-Coupled-Plasma …
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An experimental approach to thermal and solar weathering of Mercury's crust
… feldspar, enstatite orthopyroxene, and diopside clinopyroxene. Our results indicate that sodium rich feldspars have the potential to contribute sodium to the exosphere, but in order to to produce potassium from the surface, more potassium rich felspars may be necessary. Calcium and magnesium are …
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Petrology and structure of the Glen Quadrangle, southeastern Adirondacks, NY
… which were deformed and recrystallized under clinopyroxene-garnet granulite facies conditions during late Precambrian time. Metasedimentary rocks include calcic and dolomitic marble, metapelites, and metaquartzites. Rocks of known igneous origin include metagabbros, a …
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Geobarometry, phase relations and elasticity of eclogite under conditions of Earth’s upper mantle
Eclogite rocks, composed mainly of garnet and clinopyroxene, form principally as a metamorphic product of oceanic crust as it undergoes subduction. The equilibrium between garnet and clinopyroxene is sensitive to temperature and pressure, therefore eclogitic outcrops and xenoliths can reveal …
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Magmatic processes recorded in crystals from intraplate basalt volcanoes, Kaikohe-Bay of Islands volcanic field, New Zealand
… monogenetic volcanic field. The plagioclase, clinopyroxene and olivine phenocrysts all represent a diverse crystal cargo. Plagioclase have relic cores that are more sodic and more calcic than the equilibrium groundmass crystals. They have 87Sr/86Sr ratios that are either mantlelike (~0.7030) …
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Some aspects of the geochemistry of high-temperature peridotites and megacrysts from the Jagersfontein kimberlite pipe, South Africa
… suite is represented by olivine, orthopyroxene, clinopyroxene and garnet. The megacrysts show features which are unique to Jagersfontein, a particularly notable feature being the absence of ilmenite and ilmenite-silicate intergrowths. Major element and REE compositions of the Cr-poor megacryst …
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The geochemistry and petrology of the Rodrigues Ridge (Western Indian Ocean)
… the most western site contained any phenocryst clinopyroxene. Phenocryst olivine was in the range Fo88-79 and plagioclase was in the range An79-60. Where present the clinopyroxene was titaniferous (2.0-3.7% TiO2) in the range Ca4852Mg30-19Fe 19.33. The Rodrigues Ridge lavas are transitional …
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Geochemistry and petrogenesis of the Tsirub nephelinite-basanite intrusions, Aus, southern Namibia
… comprising alkali feldspar (orthoclase) and clinopyroxene (diopside and aegerine-augite) occur in the two major intrusive bodies.
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Isotopic systematics and mass transfer in amphibolite-grade mylonites
… mafic layer composed largely of clinopyroxene and albitic plagioclase (An₃). The final product of these reactions was a K-feldspar/plagioclase (An₉)-rich amphibolite. Mass balance relations show that the amphibolite-forming reactions required an influx of Fe²⁺ and Mg²⁺ cations, …
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A detailed geochemical investigation of diamond-bearing eclogite xenoliths from the Kaalvallei kimberlite, South Africa
… bimeneralic assemblages of garnet and clinopyroxene. Thirteen xenoliths contain accessory diamond with graphite on diamond surfaces. One has accessory ilmenite. The rocks are well equilibrated and are classified as Group 1 eclogites, based on their mineral textures and compositions. The …
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Megacryst suite from the Salpeterkop carbonatite complex, Sutherland, Northern Cape, South Africa: an in-depth geochemical study
… from the Salpeterkop complex, South Africa. The clinopyroxene, amphibole, phlogopite and ilmenite megacrysts all appear to be cogenetic, and based on known mineral relationships and intergrowths from xenoliths in the complex, the apparent order of mineral crystallisation is as follows: phlogopite …
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Water solubility in diopside
… Due to the low solubility of aluminum in clinopyroxene at high pressure, the data on pure diopside are probably a good guide for the water solubility in clinopyroxenes under the conditions of the deeper upper mantle. Since water solubility in diopside under those conditions is order of …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 2)
… porphyritic, containing phenocrysts of olivine, clinopyroxene, amphibole, feldspar, Fe-Ti oxide and in one sample nepheline and garnet, which are typically set in a fine-grained groundmass of clinopyroxene, feldspar or nepheline, Fe-Ti oxide, lesser olivine and accessory apatite and titanite …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 1)
… porphyritic, containing phenocrysts of olivine, clinopyroxene, amphibole, feldspar, Fe-Ti oxide and in one sample nepheline and garnet, which are typically set in a fine-grained groundmass of clinopyroxene, feldspar or nepheline, Fe-Ti oxide, lesser olivine and accessory apatite and titanite …
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Carbon systematics of the Icelandic crust and mantle
… apparatus. The experiments have shown that clinopyroxene- liquid barometry is more reliable than multi-reaction barometry. However, knowledge of equilibrium clinopyroxene compositions is crucial for accurately determining pressure using the clinopyroxene-liquid barometer. More experiments …
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A comparison of melt depletion, thermal structure and metasomatism of proterozoic mantle lithosphere in the Namaqua-Natal and Rehoboth Provinces of Southern Africa
… MREE - HREE abundances and patterns, while most clinopyroxenes have negatively sloping REE patterns with maximum enrichments in Nd and Sm. The average extents of melting beneath both Proterozoic provinces are moderate, and the samples are more fertile, on average, than cratonic lithospheric …
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