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Showing 1 to 20 of 175 for “"biotite"”.
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Factors Influencing Biotite Weathering
Weathering of biotite supplies nutrients such as K+ and weathers into vermiculite/montmorillonite or kaolinite, which have varying influences on soil properties and characteristics. This study was conducted to determine if the weathering mechanisms of biotite are controlled by temperature, or if …
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Ferric/ferrous determinations in synthetic biotite
… conditions of formation were examined for two biotite compositions: annite (K₂Fe₅Al₄Si₅O₂₀(OH)₄) and siderophyllite (K₂Fe₆Al₂Si₆O₂₀(OH)₄). The synthesized phases were annealed at fixed hydrogen fugacities using both the solid oxygen buffering technique of Eugster (1957) and the H₂ buffering …
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Use of biotite for strontium age measurements
Thesis. (Ph.D.) Massachusetts Institute of Technology. Dept. of Geology, 1951.
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Biotite oxidation: an experimental and thermodynamic approach
… generally believed that oxidation of ferruginous biotites proceeds by the oxybiotite substitution: Fe²⁺ + OH = Fe³⁺ + 0²⁻ + ½H₂ The role of this mechanism as an equilibrium process in hydrothermal systems was studied for two compositions, annite, KFe₃,AISi₃O₁₀(OH)₂, and siderophyllite, …
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Recent two-feldspar, Ti-in-biotite, and garnet-biotite geothermometry of the Frontenac terrane and Adirondack Lowlands, Grenville Province, Canada and the United States
… not the BLSZ is a discontinuity, we used garnet-biotite, Ti-in-biotite, and two-feldspar geothermometry and we examined the geochemistry of Adirondack Lowlands and Frontenac terrane pelites. Rare-earth elements and trace element concentrations reveal a shale protolith for the Adirondack Lowlands …
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A powder x-ray diffractometer study of the phlogopite-biotite series
Thesis. (Ph.D.) Massachusetts Institute of Technology. Dept. of Geology and Geophysics, 1955.
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X-Ray Study of Biotite From the Scott Mine, Sterling Lake, New York
Made available in DSpace on 2014-12-04T19:13:40Z (GMT). No. of bitstreams: 1 5805389.pdf: 2293361 bytes, checksum: 0919769ce1615388a8d0f9b4106c5f62 (MD5) Previous issue date: 1958
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A iron-57 Moessbauer study on the thermal oxidation of iron in biotite mica.
… the oxidation in air of a well characterized biotite sample. Large single crystal wafers were annealed at various temperatures up to 875$\sp\circ$C and for various times up to 94 hours. The oxidation proceeds primarily via the oxyannite reaction: $\rm (Fe\sp{2+} + OH\sp-)\sb{mica} \to …
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Major and trace element characteristics of biotite and chlorite as proxies for gold ore mineralization
… Major and trace element characteristics of biotite and chlorite were analyzed from a representative collection of rock types of different degrees of alteration from the Pampalo deposit. The main aim of this study was identifying possible correlation of changes in the elemental composition of …
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Garnet-biotite thermometry, garnet-aluminum silicate-silica-plagioclase barometry, and Emp monazite geochronology of the early Proterozoic Ivanpah Mountains, eastern Mojave Desert, Se California
… barometry and garnet-biotite thermometry, were ∼4.0kb and >700°C, respectively. Peak metamorphic-T's were recorded by the largest garnet studied; Electron Microprobe Analysis on monazite, using U-Th-Pb radioactive decay, suggest metamorphism occurred between 1752 …
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Petrogenesis of a migmatite, Penobscot County, Maine: ultrametamorphism or intrusion?
The Clifton Migmatite crops out between the biotite grade Bucksport Formation (predominantly calcareous pelitic quartzite) on the west, the Lucerne Pluton (biotite granite) on the southeast, and the Parks Pond Pluton (mafic granite to quartz syenite) on the northeast. The Parks Pond crystallized at …
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Sulfidation of synthetic biotites
… to investigate the systematic relation between biotite composition on the join phlogopite-annite and the composition of pyrrhotite. In an attempt to bracket the sulfide-silicate compositional pairs, three layers within a single capsule were used: 1) pyrite + Fe-rich biotite in the top, 2) …
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A chemical study of the silicate minerals of the Great Gossen Lead and surrounding rocks in southwestern Virginia
… system, and Fe⇄Mg distribution in biotite and garnet are approximately 400-460°C. Using the sphalerite geobarometer, metamorphic pressures were found to have been equal to or greater than 4 kbar. Fine- to medium-grained garnet-chlorite-biotite-quartz-muscovite schists and gneisses …
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The Evolution of the Los Negritos Porphyry Copper Deposit, Coquimbo, Chile: Geological, Geochronological, Mineralogical and Geochemical Evidence
… intrusive rock types: plagioclase quartz biotite porphyry (P1b and P1a dated at 109.60± 0.75 Ma and 107.22± 0.40 Ma); plagioclase biotite porphyry (P2: 106.30 ± 0.47 Ma); and quartz plagioclase biotite porphyry (P3: 106.19 ± 0.42 Ma). These units are cut by late‐ to post‐mineral …
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Magmatism, Deformation And Mesothermal Metasomatism: Interpretation Of Aluminosilicate Mineral Assemblages In The Cargo Muchacho Mountains, Southeastern California
… Feldspar Zone, with quartz-oligoclase-K-feldspar-biotite-epidote-magnetite, (b) the Muscovite Zone, with quartz-muscovite-biotite-magnetite-tourmaline-apatite, and (c) the Kyanite Zone, with quartz-kyanite-muscovite-magnetite-rutile-tourmaline-apatite (with or without andalusite, pyrophyllite, …
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Archean metamorphism in northwestern Ontario and southeastern Manitoba
… hypersthene ± clinopyroxene granulites, biotite, biotite-garnet, and biotite-garnet-cordierite paragneisses (Fig. 3). Garnet cordierite geobarometry yielded pressures of 3.8-6.S kb. The metamorphic temperatures increased slightly for the four lithologies: biotite gneisses (<610-650°C), …
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An investigation of a polymetamorphic terrain using <sup>40</sup>Ar-<sup>39</sup>Ar geochronology
… the UV laser has been used to drill into biotite inclusions within garnet to look at the shielding effect of the garnet lattice, and to drill depth profiles into garnet to measure helium diffusion in laboratory experiments. <br></br><br></br>The south-western Montana region of the …
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Geology of the Snip Mine, and its relationship to the magmatic and deformational history of the Johnny Mountain area, northwestern British Columbia
… altered with abundant vein let and pervasive biotite. The deposit, termed the Twin zone, is the largest of numerous shear veins in the mine workings. It contains just under 30 tonnes of gold. The Twin zone is composed of four ore types that are mineralogical end members of two distinctive …
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