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231	Deep fluid characteristics in the subduction zone: A window from metamorphic quartz veins / 変成石英脈を用いた沈み込み帯深部流体組成の研究 Yoshida, Kenta 23 March 2015 (has links) 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18806号 / 理博第4064号 / 新制\|\|理\|\|1585(附属図書館) / 31757 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授平島崇男, 教授大沢信二, 准教授河上哲生 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM fluid inclusion aqueous fluid B-Li-Cl composition crush-leach method Sanbagawa metamorphic belt focused ion beam X-ray CT 400
232	The effects of magmatic evolution, crystallinity, and microtexture on the visible/near-infrared and thermal-infrared spectra of volcanic rocks Noel A Scudder (16649295) 01 August 2023 (has links) <p>The natural chemical and physical variations that occur within volcanic rocks (petrology) provide critical insights into mantle and crust conditions on terrestrial bodies. Visible/near-infrared (VNIR; 0.3-2.5 µm) and thermal infrared (TIR; 5-50 µm) spectroscopy are the main tools available to remotely characterize these materials from satellites in orbit. However, the accuracy of petrologic information that can be gained from spectra when rocks exhibit complex variations in mineralogy, crystallinity, microtexture, and oxidation state occurring together in natural settings is not well constrained. Here, we compare the spectra of a suite of volcanic planetary analog rocks from the Three Sisters, OR to their mineralogy, chemistry, and microtexture from X-ray diffraction, X-ray fluorescence, and electron microprobe analysis. Our results indicate that TIR spectroscopy is an effective petrologic tool in such rocks for modeling bulk mineralogy, crystallinity, and mineral chemistry. Given a library with appropriate glass endmembers, TIR modeling can derive glass abundance with similar accuracy as other major mineral groups and provide first-order estimates of glass wt.% SiO2 in glass-rich samples, but cannot effectively detect variations in microtexture and minor oxide minerals. In contrast, VNIR spectra often yield non-unique mineralogic interpretations due to overlapping absorption bands from olivine, glass, and Fe-bearing plagioclase. In addition, we find that sub-micron oxides hosted in transparent matrix material that are common in fine-grained extrusive rocks can lower albedo and partially to fully suppress mafic absorption bands, leading to very different VNIR spectra in rocks with the same mineralogy and chemistry. Mineralogical interpretations from VNIR spectra should not be treated as rigorous petrologic indicators, but can supplement TIR-based petrology by providing unique constraints on oxide minerals, microtexture, and alteration processes.</p> Igneous and metamorphic petrology Mineralogy and crystallography Planetary geology Volcanology spectroscopy petrology thermal infrared visible/near-infrared crystallinity microtexture remote sensing linear deconvolution
233	Developing a Useful Set of Proxy Elements for the Targeting and Exploration of Gold Deposits, Black Hills, South Dakota Harp, Michael T. 13 December 2010 (has links) No description available. Geographic Information Science Geological Geology Mineralogy Mining Petrology Black Hills gold proxy elements metamorphic rocks
234	Epitaxy and Characterization of Metamorphic Semiconductorsfor III-V/Si Multijunction Photovoltaics Boyer, Jacob Tyler January 2020 (has links) No description available. Materials Science Heteroepitaxy metamorphic semiconductors III-V on Si dislocations epitaxial growth electron channeling contrast imaging photovoltaics MOCVD GaP on Si GaAsP on Si TDD
235	Petrology and Geochemistry of the Tuffaceous Footwall Rocks of the Williams Ore Zone, Hemlo Area, Ontario McIlveen, Douglas G. 04 1900 (has links) <p> The recent discovery of ore grade gold in the Hemlo area of Northern Ontario has provided the initiative for extensive exploration in that region. This study concentrates on rocks from the footwall to the ore zone on the Williams property of Long Lac Mineral Exploration. </p> <p> The footwall rocks consist of fine grained, finely laminated tuffs. The suite has undergone low grade regional metamorphism. Retrograde metamorphic effects are also present but appear to be confined to certain bands. Some of the minerals may have been introduced by the action of metasomatic fluids. </p> <p> The tuffs are quite felsic and many have the composition of a rhyolite. Samples tested for gold have up to 200 times the background concentration of a rhyolite . The gold is associated with high Sio2 and K20 and low Al2O3, CaO, Na2O, Fe2O3 and MgO contents. </p> <p> The ore deposit is similar in many respects to the Bousquet deposit of Northern Quebec. The Bousquet deposit has been interpreted as syngenetic by some authors and therefore it is quite possible that the Hemlo deposit is syngenetic as well. However the metamorphism and possible metasomatism that these rocks have undergone suggests that it may be an epigenetic deposit. Due to the limited number of samples in this study it could not conclusively be determined which hypothesis is correct. </p> / Thesis / Bachelor of Science (BSc) Petrology Geochemisty Tuffaceous Foot-wall rocks ore grade gold Hemlo Area, Ontario Bousquet deposit metasomatic fluids Retrograde metamorphic effects
236	Deformation and Fluid History of Late Proterozoic and Early Cambrian Rocks of the Central Appalachian Blue Ridge Chandonais, Daniel 23 July 2012 (has links) No description available. Geology Fluid History Appalachian Geology Blue Ridge Fluid Inclusions Quartz veins Kinematic Evolution Cambrian Geology Metamorphic Petrology tectonites anticlinorium Blue Ridge Anticlinorium Grambrill State Park western Maryland Geology.
237	Eclogites and eclogites: Oxygen isotope evidence of a shared subduction origin for Franciscan eclogites and Moses Rock eclogite xenoliths Hoover, William F. 03 June 2014 (has links) No description available. Petrology Geochemistry Geology Geological eclogite Franciscan Colorado Plateau Navajo Volcanic Field xenolith Moses Rock oxygen isotope metamorphic petrology garnet zoning diatreme subduction accretionary wedge California Four Corners
238	Different Approaches to Improve Metamorphic Buffer Layers Grown on a GaAs Substrate SAHA, SUDIP K. 10 1900 (has links) <p>Metamorphic buffer (MB) layers were studied as a means to grow epilayers on top of a GaAs substrate which have different lattice constant than the GaAs. Growths were done by molecular beam epitaxy on a GaAs (001) substrate. The growths of step-graded InGaAs and InGaAsP MBs have been investigated using both linear and logarithmic grading profiles. The logarithmic grading profile shows slight improvement in the crystal quality over the linear grading profiles. This is an indication that instead of increasing the strain with the same grading rate, it may be helpful to have higher grading rate at the beginning and lower grading rate at the end of the buffer. InGaAsP graded buffers were grown where group III ratio was kept fixed. However due to the existence of phase separation and lower relaxation the quaternary growths exhibited no performance improvement as might have been expected from growths with only group V grading. Also, the effects of using an InGaP layer grown at low temperature before the MB were determined. Quantum wells (QW), which were grown on top of the MBs, were used to probe the optical emission properties. No significant difference was observed in photoluminescence between the samples with a low temperature layer and without a low temperature layer. Annealing enhanced the PL intensity but the crystal quality degraded due to the appearance of surface defects. Surface undulations, known as “cross-hatch” (CH), were observed in the top MB layers. Atomic force microscopy (AFM) was used to analyze the surface morphology and degree of polarization (DOP) measurement was used to analyze the strain features in the final MB layer. Similar patterns of both surface morphology and strain field indicate a correlation between these two. From analysis of the periodicity of strain field and the CH, evidence was found in the support of one of the existing models of CH evolution which implies that the CH appears before the formation of MDs and subsequently MDs form at some troughs in the undulation.</p> / Master of Applied Science (MASc) Metamorphic Buffer Layers Pseudo-substrate GaAs Cross-hatch Low temperature layer InGaAs InGaAsP Semiconductor and Optical Materials
239	Magma, Mass Spectrometry, and Models: Insights into Sub-Volcanic Reservoirs and the Processes that Form Them Disha Chandrakan Okhai (18403560) 19 April 2024 (has links) <p dir="ltr">To better predict volcanic behavior, we must understand the processes that occur in the underlying magma reservoirs. This thesis contains three chapters that work together to better understand processes that occur in sub-volcanic reservoirs. Chapter 2 is a study of an ancient, coupled volcanic-plutonic system to determine the link between the volcanic and plutonic parts of the system. The IXL-Job Canyon magmatic system is an ~28-29 Ma system, which shows a rapid transition between eruption of tuffs and lava flows to construction of an upper-crustal pluton, via incremental emplacement. The system experienced an eruptive hiatus during and after pluton construction, until the eruption of a newly identified, younger, rhyolitic tuff. This work suggests that the absence of volcanic activity at the surface does not mean that the underlying magmatic plumbing system is also inactive. Chapter 3 compiles existing U-Pb zircon ID-TIMS data for upper-crustal, silicic magmatic systems, to determine the size and frequency of magmatic increments that accumulate to build up these systems. A Monte Carlo-based model is used to investigate the underlying distributions of the increment size and time between increments, and results in sizes and inter-event times that follow an exponential distribution. This work helps guide how we can try to introduce broadly generalizable complexities into thermal models of such systems. Chapter 4 focuses on organic interferences, a common issue that impacts the speed and quality of U-Pb and Pb-Pb data collected on TIMS instruments. We share two techniques used at the Purdue Radiogenic Isotope Geology Lab to first reduce and then avoid any residual organic interferences. These techniques help shorten analytical times, increasing throughput, and provide a means to reduce uncertainties on our measurements, since the presence of organic interferences can bias and increase the uncertainties on U-Pb dates.</p> Geochronology Igneous and metamorphic petrology Volcanology TIMS geochronology Volcanic-plutonic connection Emplacement of plutons IXL-Job Canyon magmatic system
240	Interaction entre fluides de différents réservoirs lors de l'évolution d'un prisme orogénique en contexte de déformation partitionnée : les Cordillères bétiques internes (Espagne) : Implications sur le transfert de métaux dans la croute / Interaction between fluids of different reservoirs in the evolution of an orogenic wedge into a context of partitioned deformation : Internal Betic Cordilleras (Spain) : Implications for the transfer of metals in the crust Dyja, Vanessa 10 March 2014 (has links) La thèse cherche à caractériser les types de fluides à différents niveaux structuraux et types de déformation. Les résultats de la Sierra Bédar indiquent le rôle d'une saumure enrichie en métaux lors des derniers stades de circulation au sein de la croûte ductile dans un domaine encore isolé des fluides de surface. Cette saumure est plus diluée à l'est dans la Sierra Almagrera et où l'impact du système décrochant va devenir de plus en plus important avec du volcanisme et de nombreux gisements. Dans le domaine fragile, des veines de quartz enregistrent des fluides de surface. Suivent des veines de quartz indiquant la réapparition des fluides métamorphiques sous-jacent. La formation de veines de sidérite-pyrite-galène-barytine montre de plus forte salinité et des rapports Cl/Br indiquant la contribution d'une autre source de saumures secondaires issues cette fois des évaporites messiniennes. Le décrochement a modifié le compartimentage de part et d'autre de la transition fragile-ductile / This thesis aim at characterizing the types of fluids concerned structural levels and style of deformation. Results from Sierra Bedar point out the role played by metal-rich brines during late stages of fluid flows within the ductile crust within a domain was still isolated from surficial fluids. Brine concentration drop in the eastern Sierra Almagrera which was progressively more impacted by the major transcurrent system with volcanism and metal ore deposits. At reaching the brittle domain, quartz veins trapped surficial fluids. Soon after, quartz veins indicating the return of metamorphic fluids. Following siderite-pyrite-galena-barite veins display higher salinities and Cl/Br ratios indicate the contribution of another secondary brine coming from early Messinian evaporites. This major transcurrent tectonics clearly modified the partitioning on both sides of the brittle-ductile transition Bétiques Trans-Alboran Metamorphic Core Complex Inclusions fluides Minéralisations Fe Minéralisations Fe-S-Pb-Ba Sources des fluides Saumures Evaporites Compartimentage Transition fragile-ductile Betic Trans-Alboran Metamorphic Core Complex Fluid inclusions Iron deposits Fe-S-Pb-Ba deposits Fluids sources Brines Evaporites Partitioning Brittle-ductile transition 549.11

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