Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 80 for “"Amphibole"”.
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The genesis of the blue amphibole asbestos of the Union of South Africa.
The blue amphibole asbestos, crocidolite, which occurs as interbedded seams in banded ironstones of the Lower Griquatown stage of the Transvaal System in the Northern Cape Province, is the finely fibrous form of the soda-amphibole riebeckite. Despite the widespread occurrence of the Precambrian …
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Iron-magnesium amphiboles: synthesis and stability with respect to temperature, pressure, oxygen fugacity, and sulfur frugacity
… to synthesize and investigate phase relations of amphiboles on the join Mg₇Si₈O₂₂(OH)₂-Fe₇Si₈O₂₂(OH)₂. Synthesized amphiboles from Mg₆Fe₁Si₈O₂₂(OH)₂ to Mg₁Fe₆Si₈O₂₂(OH)₂ are optically orthorhombic. Variation of unit cell parameters with composition suggests that they are members of a single, …
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The Effects of Amphibole- and Sulfide-Producing Melts on Crustal Strength in Gabbros of Lower Oceanic Crust in Oceanic Core Complexes, Mid-Atlantic and Southwest Indian Ridges
… present in the dikelets. LA-ICP-MS is used on amphibole to determine if its origin is igneous or metamorphic. The temperature of formation was calculated for amphibole and estimated for sulfides. Ferro-hornblende is the dominant amphibole observed in dikelets from the MAR. Pyrite is the common …
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Sodium metasomatism and magnesio-riebeckite mineralization in the Wilson Ridge pluton
… contains a rare occurrence of hydrothermal sodic amphibole. hydrothermal amphibole occurs as fracture coatings, veinlets, dense stockwork-type networks, and diffusive alteration fronts. Electron microprobe analyses of the hydrothermal amphibole reveal a range of Na-rich compositions, most notably …
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THE ROLE OF THE MACROPHAGE IN ASBESTOS INDUCED AUTOANTIBODY PRODUCTION
… However, the exact mechanism by which Libby amphibole asbestos generates autoimmune responses is unclear. To elucidate a possible mechanism for asbestos induced autoimmunity, the cellular effects of Libby amphibole asbestos were characterized in vitro using a phagocytic murine macrophage cell …
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THE ROLE OF THE MACROPHAGE IN ASBESTOS INDUCED AUTOANTIBODY PRODUCTION
… However, the exact mechanism by which Libby amphibole asbestos generates autoimmune responses is unclear. To elucidate a possible mechanism for asbestos induced autoimmunity, the cellular effects of Libby amphibole asbestos were characterized in vitro using a phagocytic murine macrophage cell …
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Aspects of the geology, geochemistry and metamorphism of the lower orebody, Broken Hill deposit, Aggeneys
… proportions of (Fe,Mn)-rich silicates (garnet, amphibole, olivine, orthopyroxene, pyroxenoid), quartz and Cu-Pb-Zn-sulphides. These minerals occur in mm- to 5 cm-thick bands and are often traceable over tens of metres. The well preserved banding is considered to represent bedding. Five different …
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Deformation Mechanisms and Strain Localization in the Mafic Continental Lower Crust
… a compositionally-layered mafic complex made of amphibole-rich and amphibole-poor metagabbros. Findings of case-study 2 show that during prograde metamorphism (T > 800 °C), the presence of amphibole undergoing dehydration melting reactions is key to weakening and strain localization. Dehydration …
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The interaction between chemical and mechanical processes during metamorphism: a microstructural and petrologic study of amphibolite shear zones, Cheyenne Belt, Southeastern Wyoming
… strain transition is marked by the rotation of amphibole and plagioclase aggregates into parallelism with the shear zone boundary and progressive grain size reduction. These observations indicate that strain magnitude increases across the shear zone. Detailed petrologic and microstructural …
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The structure and metamorphism of the Santa Marta area, Colombia, South America
… which account for the general absence of Ca-amphibole and the abundance of chlorite + carbonate assemblages. Local occurrences of coarse grained amphibole schists radiometrically determined to be Cretaceous in age apparently survived the high PCO2 conditions.</p> <p>The Gaira Group is …
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Megacryst suite from the Salpeterkop carbonatite complex, Sutherland, Northern Cape, South Africa: an in-depth geochemical study
… 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 → ilmenite → …
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Documenting multiple metasomatic events within the Finero phlogopite peridotite using chlorine isotopes, Ivrea zone, Italy
… in pervasive development of phlogopite and amphibole throughout much of the body, as well as the formation of phlogopite-rich segregations. Previous trace element and isotopic data have been interpreted by different authors to reflect metasomatism induced by slab-derived, rift-related …
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Characterization of the mineralized albitite bodies at Biggejavri, Kautokeino Greenstone Belt, Finnmark, Northern Norway
… mineralogy observed in the Biggejavri area. Amphibole from all units of the Biggejavri U-REE occurrence as well as the Bidjovagge Cu-Au deposit were analyzed using FE-SEM, automated mineralogy, EPMA, and LA-ICP-MS. Trace elements such as Ni and Cr are highest in amphibole in the high Mg …
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Controls of Melt Genesis and Evolution at Buldir Volcano in the Western Aleutian Island Arc
… to fractional crystallization and the removal of amphibole from mafic melts in crustal magma chambers. For this study, geochemical data were collected for 50 lavas from Buldir Volcano, the westernmost emergent volcano in the Aleutian island arc, to investigate the role of amphibole fractionation …
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Melanges and Glaucophanic Schists of the Mona Complex (Precambrian), Southeast Anglesey, North Wales
Amphibole distribution and zoning patterns suggest metamorphism in a subduction complex above a northwesterly dipping subduction zone. These rocks were among the earliest accreted material and not exposed to the thermal conditions of the mature subduction complex.
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 2)
… 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 (sphene). With the …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 1)
… 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 (sphene). With the …
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The metamorphic evolution of an ancient accretionary prism in the southern zone of the Damara Belt in Namibia
… an inferred peak mineral assemblage of zoned amphibole, epidote, rutile, quartz, biotite and in some cases, chlorite and sphene. The amphibole and micaceous minerals define a distinct fabric. None of the minerals occur as porphyroblasts that overprint this fabric.
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The Lithology of Herman and Campbell Beach of Glacial Lake Agassiz in the Area of Larimore and Arvilla, North Dakota
… both beaches are: magnetite, ilmenite, biotite, amphibole, tourmaline, and hyalophane.</p>
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Relationships between crystal structure, bonding and thermal stability of amphiboles
… in structure and chemical composition of the amphiboles and the wide range of their occurrence suggest that the amphiboles are potential index minerals for the physical conditions of their formation. Hydrothermal stability studies of several amphibole endmembers have demonstrated that the …
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