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1
Sheehan, Laura R. "Sedimentary and petrologic analysis of the Mississippian Price Formation at Sherwood Lake, West Virginia." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2544.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains ix, 132 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 106-109).
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Karel, Patrick Robert. "Seismic Analysis of the Tonga Subduction Zone and Implications on the Thermo-Petrologic Evolution of Deep Subduction." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1313773845.
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Cunderla, Brent Joseph. "Stratigraphic and petrologic analysis of trends within the Spencer Formation sandstones : from Corvallis, Benton County, to Henry Hagg Lake, Yamhill and Washington counties, Oregon." PDXScholar, 1986. https://pdxscholar.library.pdx.edu/open_access_etds/3588.
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Within the thesis study area Spencer Formation arkosic/arkosic lithic sandstone lithofacies of Narizian age crop out in a sinuous north-northwesterly band from the Corvallis area into the Henry Hagg Lake vicinity ten kilometers southwest of Forest Grove, Oregon.
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Lindeberg, Tomas. "Indium Analysis and Small-scale Distribution in Sulphides from the Lindbom Prospect, Långban Area, Western Bergslagen Ore Province." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-196479.
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Indium is extensively used in LCD screens and solar cells. It is mainly produced as a byproduct during ore processing. With ever increasing demand for indium and most of the production being restricted to a few countries new sources for indium are needed. In Sweden, the westernmost Bergslagen is the only area, which is known to exhibit minerals with essential indium. The indium mineralisations at Långban, the Linbom prospect, which are studied in this bachelor’s thesis show several trends. The most notable is the copper indium trend seen in sphalerite. A likely substitution based on similar ionic radii and charges is Cu1++ In3+ ↔ 2Zn2+.Usually when cassiterite is associated with similar polymetalic indium bearing mineralisations as at Långban there is also high concentrations in cassiterite. This has previously not observed in Sweden, however during this project concentrations were indeed found in cassiterite.
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Nejedlik, John. "Petrographic image analysis as a tool to quantify porosity and cement distribution." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09SM/09smn417.pdf.
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Includes bibliographical references (leaves 153-157). Petrographic image analysis proved particularly useful in determining the parameters for statistical analysis for the simple mineralogies displayed in the samples from the Hutton Sandstone. Concentrates on establishing techniques for statistical study of data collected by PIA to subdivide the framework grains from the porosity or cement.
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DeBuhr, Christopher Leonard. "Metamorphic petrology and mass balance analysis in the Bugaboo contact aureole." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ49488.pdf.
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Helbing, Heiko. "No suture in the Sardinian Variscides a structural, petrological and geochronological analysis /." Tübingen : Univ, 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10733113.
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Koebli, Danielle. "A Geochemical and Petrological Analysis of the San Rafael Volcanic Field, Utah." Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7417.
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The San Rafael Volcanic Field, Utah, is a 4.6 Ma extinct monogenetic field that is found in the Northern Transition Zone of the Colorado Plateau. The field has been eroded, leaving the dikes, conduits, and sills visible. Within the sills we see evidences of immiscibility in the form of an intermediate syenite (~50 wt% SiO2) enclosed in a mafic shonkinite (~48 wt % SiO2). Field relations indicate that sills were formed due to single events (Richardson et al., 2015), which makes in-situ differentiation the process at the origin of both rock types. Geochemical data supports differentiation of syenite and shonkinite from a single melt. The syenites are more enriched in LREE than shonkinites. The rocks are enriched in LREE compared to an OIB source, indicating melting of a hydrated lithosphere interacting with an asthernospheric garnet peridotite. Olivine with a composition of Fo80-90 further support asthernospheric origin, and pyroxenes indicate that depth of crystallization would have begun around 33 Km, indicating that the melt would have pooled at the base of the crust as it traveled, supporting base of the lithosphere origins. Rhyolite-MELTS modeling further supports differentiation within the sills as the formations of feldspars, biotite and hornblende did not occur until ~800m which would have allowed for fractional crystallization to occur, leading to the immiscibility process and resulting formation of syenite and shonkinite.
9
Khabir, Abdelrahim Mohamed. "Mesolithic and neolithic ceramics in the Central Sudan, 8th-3rd millennium B.C., with special reference to the physico-scientific approach." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389855.
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Clowes, Emma. "A microbiostratigraphical analysis of the Kolbano sequence (Jurassic to Pliocene), West Timor, and its radiolarian faunas." Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265805.
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Zhao, Xianghong. "Automated image analysis for petrographic image assessments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ62444.pdf.
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Carvalho, Cássio Santos de. "Estudo do comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas verde Amazonas, preto Cajugram e bege Ipanema - (ES) /." Rio Claro : [s.n.], 2010. http://hdl.handle.net/11449/92894.
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Orientador: Antonio Carlos ArturBanca: Fabiano Cabañas Navarro
Banca: Tamar Milca Bortolozzo Galembeck
Resumo: As rochas ornamentais Verde Amazonas, Preto Cajugram e Bege Ipanema exploradas no estado do Espírito Santo, respectivamente um charnockito, um hiperstênio monzodiorito e um ortognaisse, foram submetidas a uma bateria de ensaios físico-mecânicos e de resistência ao ataque químico sob ação controlada dos compostos NH4Cl, NaClO, C6H8O7, HCl e KOH presentes na composição de produtos de uso doméstico e de determinadas soluções concentradas dos ácidas HCl, H2SO4 e HNO3 simulando atmosferas agressivas. A avaliação dos efeitos dos agentes químicos foram realizadas à luz das variações da propagação de ondas ultrassônicas, da resistência à flexão 4 pontos e do lustro da superfície polida das rochas testadas, bem como pela caracterização dos produtos de subeflorescências e eflorescências geradas pelas reações com os ácidos. Os resultados dos diferentes testes realizados foram confrontados com as propriedades petrográficas de cada rocha. Os resultados obtidos para os parâmetros físico-mecânicos e de alterabilidade química indicam, com algumas reservas, que as três rochas são detentoras de boas qualidades para utilização como rochas ornamentais e para revestimentos em obras civis. Os estudos revelaram que o comportamento tecnológico e de alterabilidade química dos materiais avaliados é controlado pela inter-relação dos aspectos composicionais, estruturais e texturais das rochas. O charnockito Verde Amazonas, rocha verde escura megaporfirítica gnaissificada com matriz de granulação média a grossa e com elevado grau de microfissuramento transgranulares, apresentou bom desempenho no tocante a resistência mecânica, mas foi o material que mostrou maior sensibilidade aos efeitos da maioria dos agentes químicos com desbotamento, clareamento, amarelamento e ofuscamento das superfícies polidas. O Preto Cajugram com estrutura isotrópica, textura equigranular... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The Amazon Green, Cajugram Black and Ipanema Beige dimension stones explored in the state of Espirito Santo, respectively, a charnockite, a hypersthene monzodiorite and a orthogneiss, underwent a serie of physical-mechanical and resistance to chemical attack tests under controlled action of the chemicals NH4Cl, NaClO, C6H8O7, HCl and KOH, present in the composition of household products and certain concentrated solutions of the acids HCl, H2SO4 and HNO3, simulating aggressive atmospheres. The evaluation of the effects of the chemical agents was performed in the light of changes in the propagation of ultrasonic sound waves, the 4-point flexural strength and gloss of the polished surface of the tested rock samples, as well as the characterization of the products of efflorescences and subefflorescences, generated by reactions with the acids. The results of the different tests were compared with the petrographic properties of each rock. The obtained results for the physic-mechanical parameters and for the chemical alterability indicates, with some reservations, that the three rocks shows good quality for use as dimension stones and coatings in civil works. Studies show that the behavior of technology and chemical alterability of the tested materials is controlled by the interrelation of the compositional, structural and textural aspects of the rocks. The charnockite Verde Amazonas, dark green megaporphyritic gneissic rock, with medium to coarse grained matrix and a high degree of transgranular microcracking, showed good performance regarding mechanical strength, but was the most sensitive material to the effects of most chemical agents as fading, bleaching, yellowing and glare from the polished surfaces. The Preto Cajugram, with isotropic structure, medium equigranular texture, and low degree of microcracking, has the highest mechanical strengths. On the other hand, it displays the highest... (Complete abstract click electronic access below)
Mestre
13
Westby, Elizabeth G. "The Geology and Petrology of Enigmatic Rhyolites at Graveyard and Gordon Buttes, Mount Hood Quadrangle, Oregon." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2063.
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Rhyolite lava flows are found at two dome complexes at Graveyard Butte and Gordon Butte, Mount Hood Quadrangle, Oregon. At Graveyard Butte, the White River has cut a winding canyon 150 m deep, exposing at its base, a 40-meter-thick outcrop of flow-banded rhyolite (73 wt.% SiO2, 3.67±0.01 Ma) that laterally extends along the canyon wall for about 1 km. Stratigraphically above the flow-banded rhyolite is locally-erupted iron-rich andesites (lava flows, agglutinate and other pyroclastic rocks as well as clastic debris), a rhyolitic ash-flow tuff (74 wt.% SiO2), and the 2.77±0.36 Ma tholeiitic basalt lava flows of Juniper Flat (Sherrod and Scott, 1995). Roughly 2 km downstream, a phenocryst-poor, maroon-colored rhyolite (3.65±0.01 Ma) is visible again, forming steep canyon walls for about 1.6 km. A compositionally similar silicic unit is found 18 km to the northwest of Graveyard Butte at Gordon Butte. Exposed units along Gordon Butte's Badger Creek (3.64±0.03 Ma) and the southeastern upper slopes of Gordon Butte include rhyolite flows (69.6-72.1 wt.% SiO 2).
The rhyolite lava flows at Graveyard Butte and Gordon Butte's Badger Creek are nearly chemically indistinguishable and both contrast with the younger rhyolitic ash-flow tuff at Graveyard Butte and lava flows on Gordon Butte's Upper Slopes. The rhyolites of Graveyard Butte and Badger Creek are richer in Nb and Zr (30-40 ppm and 487-530 ppm, respectively) than the younger rhyolitic tuff and Upper Slopes flows (13-19 ppm and 235-364 ppm, respectively) and share characteristics with A-type granitoids. The rhyolite lavas are porphyritic (~7%) with the porphyroclasts comprising primarily individual feldspars (250-500 µm in length) with ragged margins, oscillatory zoning and less commonly, spongy cores. Other phenocrystic phases include fayalitic olivine, Fe-rich clinopyroxene, and Fe-Ti oxides.
A-type-like incompatible trace-element-enriched compositions as well as mineralogical indicators suggest rhyolite lava flows at Graveyard Butte and Gordon Butte's Badger Creek are likely generated in an extensional tectonic setting. A possible geotectonic framework for generation of these rhyolite lavas is the northward propagating intra-arc rift of the Oregon Cascades.
14
Jones, Marilyn Gail 1963. "Clay mineralogy and petrology of the Lower Cretaceous fine-grained clastic rocks, southeastern Arizona." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/558100.
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Hulett, Sam Rw. "Detrital Zircon Analysis of Permian Victoria Group Sandstones, Transantarctic Mountains, Antarctica." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1355867143.
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Cotton, Timothy Brett. "Petrological analysis of mineral scales formed during gas production from permian reservoirs in the Cooper Basin /." Title page, abstract and table of contents only, 2003. http://web4.library.adelaide.edu.au/theses/09SB/09sbc8511.pdf.
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Gillam, Daniel J. "Structural and geomechanical analysis of naturally fractured hydrocarbon provinces of the Bowen and Amadeus Basins: onshore Australia /." Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phg4758.pdf.
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De, Gasperi Patricia Martins Silva. "Estimativa de propriedades petrofisicas atraves da reconstrução 3D do meio poroso a partir da analise de imagens." [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264010.
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Orientadores: Euclides Jose Bonet, Marco Antonio Schreiner MoraesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Este trabalho tem como objetivos o estudo e a aplicação do processo de estimativa de propriedades petrofisicas a partir de informações obtidas em imagens petrográficas bidimensionais. O método assume a hipótese da homogeneidade estatística, e utiliza a simulação estocástica para a reconstrução do modelo tridimensional do meio poroso. A caracterização geométrica do meio simulado permite a elaboração de um modelo de rede para a simulação do fluxo e a estimativa da permeabilidade, fator de formação, pressão capilar por injeção de mercúrio e relação índice de resistividade versus saturação de água. Esta metodologia é aplicada a quatro sistemas porosos com diferentes níveis de heterogeneidade. Os resultados demonstram que estimativas confiáveis dependem da utilização de uma resolução apropriada de aquisição das imagens, que permita a identificação de poros e gargantas que efetivamente controlem as propriedades de fluxo do sistema. As curvas de pressão capilar simuladas sugerem a necessidade da composição de escalas. As propriedades elétricas são afetadas pela porosidade das amostras e sua confiabilidade é restrita a sistemas preferencialmente molháveis pela água
Abstract: The aim of this work is to investigate and apply a method for predicting petrophysical properties ftom bidimensional petrographic image data. Based on the assumption of statistical homogeneity, the method uses stochastic simulation to reconstruct the porous media tridimensional structure. The geometrical characterization of the simulated media allows the construction of a network model to simulate fluid flow and estimate permeability, formation factor, mercury capillary pressure curves and resistivity index as function of water saturation. This method is applied to four porous systems with different heterogeneity levels. The results demonstrate that good predictions depend on the appropriate image aquisition resolution, which identifies pores and throats that effectively control the flow properties of the system. The capillary pressure curves suggest the necessity of scale composition. The electrical properties are affected by samples porosity, with reliable estimates being restricted to water-wet systems
Mestrado
Mestre em Engenharia de Petróleo
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Sales, Hillarie Jaye. "The Wildcat Creek Tuff, Eastern Oregon: Co-eruption of Crystal-poor Rhyolite and Fe-rich Andesite with Implication for Mafic Underpinnings to Voluminous A-type Rhyolites." PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4352.
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The Wildcat Creek Tuff is a thin (~3-12 m), rhyolite to andesitic ash-flow tuff with a minimal extent of 1500 km2 in Malheur county, eastern Oregon. The previously undated tuff yielded a single crystal, anorthoclase 40Ar/39Ar age of 15.49±0.02 Ma and thus is closely related to mafic and silicic volcanism of the Columbia River Province. The tuff texturally stands out by its high proportion of co-mingled mafic inclusions appearing as dark, scoriaceous, and phenocryst-poor fragments, and their proportion dictate bulk tuff compositions ranging from rhyolite (74% SiO2) to andesite (59% SiO2). Glass analyses confirm rhyolite end member at 74-75 wt.% SiO2 and two mafic members, one at 59-60 wt.% SiO2 and the other at 56-57 wt.% SiO2. Rare plagioclase and even rarer pyroxene phenocrysts with compositions clustering at An60-74 and An35-45, and Mg17-19 and Mg80-84, respectively, similarly suggest two andesitic magmas with the 60% member being the dominant mafic composition. It has distinctly lower TiO2 and CaO, slightly lower FeO, and comparable Al2O3, MgO, and alkalis.
Eruption of crystal-poor dacitic to basaltic-andesitic cognate components is also observed in other Miocene ash-flow tuffs from eastern Oregon, like the Rattlesnake, Dinner Creek, and the Devine Canyon Tuffs, as well as other less voluminous tuffs. However, the high proportion of mafic components in the Wildcat Creek tuff seems currently unrivaled. The co-eruption of intermediate magmas with rhyolite implies that mafic magmas were tapped from a common reservoir, and these magmas increased in proportion during the course of the eruption(s). This continued up to the point where nearly all deposited tuff material consisted of andesite. This is consistent with progressively deeper magma withdrawal, in turn implying that mafic magmas resided below the rhyolites as a discrete magma batch. Dacitic components of voluminous rhyolitic tuffs have been recently interpreted as remelted samples of a crystal mush after crystal-poor rhyolites where extracted. Dacitic Wildcat Creek Tuff samples do not bear any evidence of this. To the contrary, small negative Eu anomalies, normal Ba and Sr concentrations, and nearly aphyric nature are consistent with a large portion of mixing between Wildcat Creek Tuff rhyolites and regional mid Miocene, Fe-rich, and crystal poor basaltic andesite magmas that occur ubiquitously as lava flows.
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Vaughan, Sarah J. "A fabric analysis of Late Cypriot Base Ring Ware : studies in ceramic technology, petrology, geochemistry and mineralogy." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281701.
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Base Ring Ware is one of the most distinctive and thereby important archaeological hallmarks of the Late Bronze Age in Cyprus. The technical ceramic standards achieved ·inthis ware coupled with its wide. distribution provided a valuable opportunity to study the technological skills of the ancient Cypriot craftsmen as well as to assess the degree of sophistication of their knowledge, and ability to manipulate the local ceramic material resources. By means of standardised macroscopic studies of a large sherd sample of the ware, the range and patterns of production methods were established. These data were then subjected to s ta tis tical clus tering procedures to discover any chronologi'cal, geographical or technical production patterns for the ware. In addition, geochemical analyses were performed on a representative set of sherds to provide a basis for characterising the ware's general geological composition and to determine whether any local variations in the fabric could be identified. For purposes of material comparisons, forty clay samples of various mineralogical types were collected from Cyprus from deposits near the Late Cypriot sites represented by the Base Ring sherds. These clays were also subjected to geochemical analysis and statistical procedures to determine whether any of them could provide useful compositional parallels to the materials of the archaeological samples. The sherds were then examined petrographically and by scanning electron microscopy, microprobe and X-ray diffraction analysis to provide complementary and corroborative data for the geochemical profiles. The Cypriot clay samples were used for manufacturing and firing experiments to compare with Base Ring production techniques, and were subjected to the same analytical procedures as were the sherds. The combined analytical and technical data were then considered for both sherds and clays to determine the degree to which they contributed to a consistent and overall geoiogical characterisation of Base Ring materials and fabrics, and the degree to which they provided important insights into the relative sophistication and regional nature of the Late Cypriot ceramic industry which produced .this remarkable ware
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Carvalho, Cássio Santos de [UNESP]. "Estudo do comportamento tecnológico e de alterabilidade das rochas ornamentais silicáticas verde Amazonas, preto Cajugram e bege Ipanema - (ES)." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/92894.
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As rochas ornamentais Verde Amazonas, Preto Cajugram e Bege Ipanema exploradas no estado do Espírito Santo, respectivamente um charnockito, um hiperstênio monzodiorito e um ortognaisse, foram submetidas a uma bateria de ensaios físico-mecânicos e de resistência ao ataque químico sob ação controlada dos compostos NH4Cl, NaClO, C6H8O7, HCl e KOH presentes na composição de produtos de uso doméstico e de determinadas soluções concentradas dos ácidas HCl, H2SO4 e HNO3 simulando atmosferas agressivas. A avaliação dos efeitos dos agentes químicos foram realizadas à luz das variações da propagação de ondas ultrassônicas, da resistência à flexão 4 pontos e do lustro da superfície polida das rochas testadas, bem como pela caracterização dos produtos de subeflorescências e eflorescências geradas pelas reações com os ácidos. Os resultados dos diferentes testes realizados foram confrontados com as propriedades petrográficas de cada rocha. Os resultados obtidos para os parâmetros físico-mecânicos e de alterabilidade química indicam, com algumas reservas, que as três rochas são detentoras de boas qualidades para utilização como rochas ornamentais e para revestimentos em obras civis. Os estudos revelaram que o comportamento tecnológico e de alterabilidade química dos materiais avaliados é controlado pela inter-relação dos aspectos composicionais, estruturais e texturais das rochas. O charnockito Verde Amazonas, rocha verde escura megaporfirítica gnaissificada com matriz de granulação média a grossa e com elevado grau de microfissuramento transgranulares, apresentou bom desempenho no tocante a resistência mecânica, mas foi o material que mostrou maior sensibilidade aos efeitos da maioria dos agentes químicos com desbotamento, clareamento, amarelamento e ofuscamento das superfícies polidas. O Preto Cajugram com estrutura isotrópica, textura equigranular...
The Amazon Green, Cajugram Black and Ipanema Beige dimension stones explored in the state of Espirito Santo, respectively, a charnockite, a hypersthene monzodiorite and a orthogneiss, underwent a serie of physical-mechanical and resistance to chemical attack tests under controlled action of the chemicals NH4Cl, NaClO, C6H8O7, HCl and KOH, present in the composition of household products and certain concentrated solutions of the acids HCl, H2SO4 and HNO3, simulating aggressive atmospheres. The evaluation of the effects of the chemical agents was performed in the light of changes in the propagation of ultrasonic sound waves, the 4-point flexural strength and gloss of the polished surface of the tested rock samples, as well as the characterization of the products of efflorescences and subefflorescences, generated by reactions with the acids. The results of the different tests were compared with the petrographic properties of each rock. The obtained results for the physic-mechanical parameters and for the chemical alterability indicates, with some reservations, that the three rocks shows good quality for use as dimension stones and coatings in civil works. Studies show that the behavior of technology and chemical alterability of the tested materials is controlled by the interrelation of the compositional, structural and textural aspects of the rocks. The charnockite Verde Amazonas, dark green megaporphyritic gneissic rock, with medium to coarse grained matrix and a high degree of transgranular microcracking, showed good performance regarding mechanical strength, but was the most sensitive material to the effects of most chemical agents as fading, bleaching, yellowing and glare from the polished surfaces. The Preto Cajugram, with isotropic structure, medium equigranular texture, and low degree of microcracking, has the highest mechanical strengths. On the other hand, it displays the highest... (Complete abstract click electronic access below)
22
McDaniel, Kyle. "Origin of Crystal Rock Cave, Ohio, USA and its record of Lake Erie variation through speleothem analyses." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1530544408347209.
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Ahsan, Abul. "Petrology and facies analysis of the upper sand, Hyland Bay Formation, the Petrol Gas Field, Bonaparte Gulf, Northern Australia /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09S.B/09s.ba2874.pdf.
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Kaya, Egemen Tangut. "Estimation Of Expected Monetary Values Of Selected Turkish Oil Fields Using Two Different Risk Assessment Methods." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/1091495/index.pdf.
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Most investments in the oil and gas industry involve considerable risk with a wide range of potential outcomes for a particular project. However, many economic evaluations are based on the &ldquomost likely&rdquo
results of variables that could be expected without sufficient consideration given to other possible outcomes and it is well known that initial estimates of all these variables have uncertainty. The data is usually obtained during drilling of the initial oil well and the sources are geophysical (seismic surveys) for formation depths and areal extent of the reservoir trap, well logs for formation tops and bottoms, formation porosity, water saturation and possible permeable strata, core analysis for porosity and saturation data and DST (Drill-Stem Test) for possible oil production rates and samples for PVT (Pressure Volume Temperature) analysis to obtain FVF (Formation Volume Factor) and others. The question is how certain are the values of these variables and what is the probability of these values to occur in the reservoir to evaluate the possible risks. One of the most highly appreciable applications of the risk assessment is the estimation of volumetric reserves of hydrocarbon reservoirs. Monte Carlo and moment technique consider entire ranges of the variables of Original Oil in Place (OOIP) formula rather than deterministic figures. In the present work, predictions were made about how statistical distribution and descriptive statistics of porosity, thickness, area, water saturation, recovery factor, and oil formation volume factor affect the simulated OOIP values. The current work presents the case of two different oil fields in Turkey. It was found that both techniques produce similar results for 95%. The difference between estimated values increases as the percentages decrease from 50% and 5% probability.
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MacSween, Ann. "The Neolithic and late Iron Age Pottery from Pool, Sanday, Orkney : an archaeological and technological consideration of coarse pottery manufacture at the Neolithic and late Iron Age site of Pool, Orkney incorporating X-Ray Fluorescence, Inductively Coupled Plasma Spectrometric and Petrological Analyses." Thesis, University of Bradford, 1990. http://hdl.handle.net/10454/3375.
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The Neolithic and late Iron Age pottery from the settlement site of Pool, Sanday, Orkney, was studied on two levels. Firstly, a morphological and technological study was carried out to establish a sequence for the site. Secondly an assessment was made of the usefulness of X-ray Fluorescence Analysis, Inductively Coupled Plasma Spectrometry and Petrological analysis to coarse ware studies, using the Pool assemblage as a case study. Recording of technological and typological attributes allowed three phases of Neolithic pottery to be identified. The earliest phase included sherds of Unstan Ware. This phase was followed by an assemblage characterised by pottery with incised decoration, which was stratified below a traditional Grooved Ware assemblage. The change in pottery styles and manufacturing methods with the Grooved Ware indicated that it evolved elsewhere. Grass tempered and burnished pottery characterised the Iron Age assemblage. Pottery samples from all phases of the site were analysed by XRF and ICPS. In addition, pottery from late Iron Age sites in the area was analysed for comparison with the Pool Iron Age pottery. XRF and ICPS analyses did not distinguish between either different phases at Pool or different Orcadian sites. This was attributed to the similarities in geological deposits over much of Orkney and the variations which can occur within a clay source. A clay survey was carried out in the vicinity of the site, and samples taken for comparison with the Pool pottery. Identification of rocks and minerals in thin section, and grain-size analysis, indicated that the Pool pottery was made locally to the site, and that both primary and secondary clays were used. It was concluded that petrological analysis is more suitable than elemental analysis in the study of coarse wares.
26
Barone, Jessica Lynn. "Petrological and geochemical analysis of coal mine spoil to determine the source of magnesium-rich groundwater, Star Fire Mine, Eastern Kentucky." Virtual Press, 2000. http://liblink.bsu.edu/uhtbin/catkey/1189406.
Full textAbstract:
The Star Fire Coal Mine is a large strip mining operation (10,000 acre permit) that produces mine spoil consisting of sandstones, shales, siltstones, and underclays of the Pennsylvanian Breathitt Formation. Chemical analysis of groundwater from the saturated mine spoil show unusually high magnesium concentrations, with magnesium constituting between 27 and 47 percent of the major cations. Excess magnesium in water is detrimental to plant metabolism, and its content in groundwater may limit its use for irrigation and other uses during a post-mining land use plan. Petrological methods (thin section point count analysis and x-ray diffraction) and geochemical methods (electron microprobe analysis and water extraction experiments) were performed to determine the source of magnesium in sandstone and shale samples of the Breathitt Formation. Based on mineral percents and concentrations of magnesium found in samples used for waterrock interaction samples, magnesium-rich siderite was found as the primary contributor of magnesium to the groundwater.Department of Geology
27
Murgatroyd, Jennifer Leigh. "Ancient mortar production in Ostia, Italy : builders and their choices." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:358de9ea-d89b-4053-84c7-0fdc29340bb2.
Full textAbstract:
The main objective of the research discussed in this thesis was to evaluate the methods and materials used by builders in ancient Ostia to produce mortar for masonry structures. The work was conducted with an eye toward understanding why the ancient builders selected specific materials and employed specific techniques. The research design included scientific investigations of mortar samples from selected structures in Ostia, all dated from brick stamp evidence to the 2nd century CE. The methods employed for this study included thin section petrography, modal analysis via point counting, scanning electron microscopy, X-ray diffraction, and image analysis. Results concluded the samples comprised lime binder and primarily volcanic tuff aggregates derived from the Colli Albani and Monti Sabatini volcanic districts. The selection of these aggregates was integral to mortar performance, as they contained alteration products that would have facilitated pozzolanic reactions during the production phase, greatly improving long term mortar performance and durability. Three distinct types of mortar representing unique mix designs were identified based on the material properties of the mortar samples and the dominant aggregate types. Unique mixes may have been proprietary to specific groups of builders in Ostia, which had been identified by other researchers comparing the architectural features and construction styles of various structures. The results of material analyses showed that the builders from 2nd century Ostia were highly skilled, used sophisticated techniques to produce high quality mortar, and that separate groups of builders employed unique mix designs to achieve similar results.
28
Osborn, Caleb R. "Microfacies Analysis, Sedimentary Petrology, and Reservoir Characterization of the Sinbad Limestone Based Upon Surface Exposures in the San Rafael Swell, Utah." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1414.
Full textAbstract:
The Lower Triassic Sinbad Limestone Member of the Moenkopi Formation has produced minor amounts of oil in the Grassy Trail Creek field near Green River, Utah and is present below much of central Utah including the recently discovered Covenant field. Superb outcrops of this thin (15 m), mixed carbonate-silicilastic unit in the San Rafael Swell permit detailed analysis of its vertical and lateral reservoir heterogeneity. Vertically, the Sinbad Limestone comprises three facies associations: (A) a basal storm-dominated, well-circulated skeletal-oolitic-peloidal limestone association, (B) a storm-dominated, poorly-circulated hummocky cross-stratified siliciclastic/peloidal association, and (C) a capping peritidal cross-bedded oolitic dolograinstone association. Eleven microfacies are present in 14 measured sections within the Sinbad Limestone. Lateral variation is most pronounced in the upper part of the basal limestone where storm-deposited beds pinch out over a lateral distance of one kilometer. Otherwise, individual beds and microfacies display a large degree of lateral homogeneity and regional persistence. Diagenesis is strongly controlled by microfacies. Diagenetic elements include marine fibrous calcite cements, micritized grains, compaction, dissolution and neomorphism of aragonite grains, meteoric cements, pressure dissolution, and dolomitization. The paragenetic sequence progresses from marine to meteoric to burial. Marine and meteoric cements occlude much of the depositional porosity. Hydrocarbon-lined interparticle and separate vug (largely molds) pores (1-5%) characterize the skeletal-oolitic limestones with permeability ranging from 0-100 md. Low permeability/porosity characterizes the middle silicilastic unit. The best reservoir qualities (permeability 400 md) occur in portions of the dolomitized oolitic grainstones that form the upper 2 to 3 m of the Sinbad Limestone. Fracture analysis of the studied area indicates a strong NW-SE trend. Fracture spacing is associated with lithology. Fracturing of limestone possibly displays a higher dependence upon bed thickness and microfacies type. The degree of dolomitization controls and increases fracture spacing while siltstones display more closely spaced fractures. The basal limestone unit is an oil storage unit, medial siltstones are flow baffles/barriers, and the dolostone caprock is an oil flow unit. If good connectivity through fractures can be obtained between the dolostone and limestone units, the Sinbad Limestone has potential to serve as a reservoir. This study will not only aid in future Sinbad exploration, but will serve as a model for parasequence-scale intervals in thicker mixed carbonate-siliciclastic successions.
29
Navarro, Fabiano Cabañas. "Influência da petrografia sobre a anisotropia à tensão de compressão e dilatação térmica de rochas ornamentais /." Rio Claro : [s.n.], 2006. http://hdl.handle.net/11449/103006.
Full textAbstract:
Orientador: Antonio Carlos ArturBanca: Antenor Braga Paraguassú
Banca: José Eduardo Rodrigues
Banca: Maria Heloisa Barros de Oliveira Frascá
Banca: Peter Christian Hackspacher
Resumo: Considerando um conjunto de 21 tipos de rochas utilizadas como revestimento e subdivididas em quatro conjuntos por afinidade da composição mineral (rochas carbonáticas, quartzosas, feldspáticas e quartzo-feldspáticas) foram realizados ensaios tecnológicos para a determinação do coeficiente de dilatação térmica linear e da resistência à compressão uniaxial, bem como a anisotropia dessas propriedades. Os dados tecnológicos obtidos foram correlacionados com informações petrográficas qualitativas e quantitativas referentes à composição mineral, variações texturais e estruturais determinadas em seções ortogonais entre si a partir de um sistema de referência (xyz) baseado na foliação e lineação macroscopicamente visíveis. A análise integrada dos dados utilizando estatística convencional e multivariada procurou apontar as variáveis petrográficas mais relevantes para as duas propriedades tecnológicas enfocadas e suas respectivas anisotropias. A dilatação térmica e sua anisotropia são influenciadas principalmente pela composição mineral e pela orientação preferencial dos minerais embora as microfissuras desempenhem papel importante em alguns casos. A tensão de compressão mostra sua variabilidade e anisotropia influenciadas pela granulação média, tipos de contatos minerais predominantes e padrões de microfissuras mais ou menos definidos por influência da foliação presente. Constatou-se que no conjunto analisado a presença da foliação não implica necessariamente em anisotropia das duas propriedades estudadas.
Abstract: The anisotropy of thermal expansion coefficient and compressive tensile strength were determined for 21 commercially used stones gathered in four set according the main mineral composition named carbonatic, quartz-rich, feldspar-rich and quartz-feldspar-rich rocks. Using a coordinate reference system (xyz) based on the macroscopic visible foliation and lineation the samples were submitted to normalized laboratorial analyses for determination of the both technological properties and the petrographical features such as mineral composition, texture and fabric. Additionally was carried out measurements of weathered area and microcrack quantification by image analysis and texture quantification by U-stage methods. In order to understand the relationship between the anisotropy measured and petrographical data it was applied traditional and multivariate statistical analysis. The results pointed to the great significance of mineral composition and the crystallographic preferred orientation for thermal expansion and respective anisotropy, especially to monomineralic and/or foliated rocks, in spite of some cases microcracks play this role. The compressive strength is mainly controlled by a complex interaction between grain size distribution, grain boundary and microcrack patterns related or not to foliation.
Doutor
30
Gillings, Mark. "Ceramic production in a Roman frontier zone: A comparative Neutron Activation and Petro-Textural analysis of Roman coarse pottery from selected sites on and around the Antonine wall, Scotland." Thesis, University of Bradford, 1991. http://hdl.handle.net/10454/3374.
Full textAbstract:
A series of recent excavations on the 2nd Century
AD Antonine frontier forts of the Midland Scottish
valley, have produced results which suggest that the
army was making its own pottery on an appreciable
scale. This was at a time when pottery production was
thought to have moved almost exclusively into civilian
hands.
The possible local ware groups identified by the
excavations were largely independent of firm source
indicators such as kiln and waster material and the
number of available samples was often-small.
A program of Neutron Activation and Thin Section
petrological analyses was undertaken along with an
investigation into Textural Analysis, a facet of the
Petrological toolkit. The aim was both to define the
site ware groups and a group of specialist vessels
thought to be local to Scotland, the Mortaria, and to
make statements as to their provenance.
Although the Mortaria analysis was limited by
problems of sample group size and availability, by
improving the objectivity of the statistical handling
of the derived data sets and developing methods for the
high level study of textural data, the site ware groups
were defined successfully at both the "intrall and
"inter" site levels. The analyses also furnished
interpretations as to the mode and nature of the site
production schemes.
Through the full analysis of' site Daub samples
linked to more traditional provenancing techniques, in
all but one case the ware groups could be assigned to
the source sites, where contrasting production modes
could be identified with military as opposed to
civilian production.SERC
31
Butland, Caroline. "Coal seam gas associations in the Huntly, Ohai and Greymouth regions, New Zealand." Thesis, University of Canterbury. Geological Sciences, 2006. http://hdl.handle.net/10092/1304.
Full textAbstract:
Coal seam gas has been recognised as a new, potential energy resource in New Zealand. Exploration and assessment programmes carried out by various companies have evaluated the resource and indicated that this unconventional gas may form a part of New Zealand's future energy supply. This study has delineated some of the controls between coal properties and gas content in coal seams in selected New Zealand locations. Four coal cores, one from Huntly (Eocene), two from Ohai (Cretaceous) and one from Greymouth (Cretaceous), have been sampled and analysed in terms of gas content and coal properties. Methods used include proximate, sulphur and calorifc value analyses; ash constituent determination; rank assessment; macroscopic analysis; mineralogical analysis; maceral analysis; and gas analyses (desorption, adsorption, gas quality and gas isotopes). Coal cores varied in rank from sub-bituminous B-A (Huntly); sub-bituminous C-A (Ohai); and high volatile bituminous A (Greymouth). All locations contained high vitrinite content (~85 %) with overall relatively low mineral matter observed in most samples. Mineral matter consisted of both detrital grains (quartz in matrix material) and infilling pores and fractures (clays in fusinite pores; carbonates in fractures). Average gas contents were 1.6 m3/t in the Huntly core, 4.7 m3/t in the Ohai cores, and 2.35 m3/t in the Greymouth core. The Ohai core contained more gas and was more saturated than the other cores. Carbon isotopes indicated that the Ohai gas composition was more mature, containing heavier 13C isotopes than either the Huntly or Greymouth gas samples. This indicates the gas was derived from a mixed biogenic and thermogenic source. The Huntly and Greymouth gases appear to be derived from a biogenic (by CO2 reduction) source. The ash yield proved to be the dominant control on gas volume in all locations when the ash yield was above 10 %. Below 10 % the amount of gas variation is unrelated to ash yield. Although organic content had some influence on gas volume, associations were basin and /or rank dependant. In the Huntly core total gas content and structured vitrinite increased together. Although this relationship did not appear in the other cores, in the Ohai SC3 core lost gas and fusinite are associated with each other, while desmocollinite (unstructured vitrinite) correlated positively with residual gas in the Greymouth core. Although it is generally accepted that higher rank coals will have higher adsorption capacities, this was not seen in this data set. Although the lowest rank coal (Huntly) contains the lowest adsorption capacity, the highest adsorption capacity was not seen in the highest rank coal (Greymouth), but in the Ohai coal instead. The Ohai core acted like a higher rank coal with respect to the Greymouth coal, in terms of adsorption capacity, isotopic signatures and gas volume. Two hypothesis can be used to explain these results: (1) That a thermogenically derived gas migrated from down-dip of the SC3 and SC1 drill holes and saturated the section. (2) Rank measurements (e.g. proximate analyses) have a fairly wide variance in both the Greymouth and Ohai coal cores, thus it maybe feasible that the Ohai cores may be higher rank coal than the Greymouth coal core. Although the second hypothesis may explain the adsorption capacity, isotopic signatures and the gas volume, when the data is plotted on a Suggate rank curve, the Ohai coal core is clearly lower rank than the Greymouth core. Thus, pending additional data, the first hypothesis is favoured.
32
Cassle, Christopher F. "Petrographic Analyses of Late Pennsylvanian Limestones within the Northern Appalachian Basin, USA." Ohio University / OhioLINK, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1121435271.
Full text
33
Dodson, Scott A. "Petrographic and Geochronologic Provenance Analysis of Upper Pennsylvanian Fluvial Sandstones of the Conemaugh and Monongahela Groups, Athens County, Ohio." Ohio : Ohio University, 2008. http://www.ohiolink.edu/etd/view.cgi?ohiou1218658592.
Full text
34
Gillings, Mark. "Ceramic production in a Roman frontier zone : a comparative Neutron Activation and Petro-Textural analysis of Roman coarse pottery from selected sites on and around the Antonine wall, Scotland." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3374.
Full textAbstract:
A series of recent excavations on the 2nd Century AD Antonine frontier forts of the Midland Scottish valley, have produced results which suggest that the army was making its own pottery on an appreciable scale. This was at a time when pottery production was thought to have moved almost exclusively into civilian hands. The possible local ware groups identified by the excavations were largely independent of firm source indicators such as kiln and waster material and the number of available samples was often-small. A program of Neutron Activation and Thin Section petrological analyses was undertaken along with an investigation into Textural Analysis, a facet of the Petrological toolkit. The aim was both to define the site ware groups and a group of specialist vessels thought to be local to Scotland, the Mortaria, and to make statements as to their provenance. Although the Mortaria analysis was limited by problems of sample group size and availability, by improving the objectivity of the statistical handling of the derived data sets and developing methods for the high level study of textural data, the site ware groups were defined successfully at both the "intrall and "inter" site levels. The analyses also furnished interpretations as to the mode and nature of the site production schemes. Through the full analysis of' site Daub samples linked to more traditional provenancing techniques, in all but one case the ware groups could be assigned to the source sites, where contrasting production modes could be identified with military as opposed to civilian production.
35
Ligouis, Bertrand. "La grande couche de bourran du bassin stephanien de decazeville (aveyron) : petrologie et environnements de depot du charbon, genese d'une veine puissante." Orléans, 1988. http://www.theses.fr/1988ORLE2027.
Full textAbstract:
Etude petrographique de la grande couche de charbon de bourran, d'age stephanien b-c, bassin de decazeville. Les variations verticales de la composition du charbon conduisent a un decoupage du profil de couche en intervalles. L'ensemble des caracteres petrographiques d'un intervalle definit un type petrographique. Cinq types sont identifies. L'utilisation des maceraux comme marqueurs botaniques et la confrontation des donnees petrographiques et palynologiques permettent de relier chacun des types petrographiques a un type de vegetation et a un environnement de depot. Ainsi, le depot du charbon a eu lieu dans la partie centrale du bassin, dans une cuvette a subsidence rapide, occupee par une nappe d'eau de niveau moyen a eleve. Le charbon apparait comme un depot allochtone
36
Powell, Kristopher Michael. "Facies Analysis, Sedimentary Petrology, and Reservoir Characterization of the Lower Triassic Sinbad Limestone Member of the Moenkopi Formation, Central Utah: A Synthesis of Surface and Subsurface Data." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6672.
Full textAbstract:
Lower Triassic strata in the Wellington Flat and Tully cores reflect a lateral transition from shallow water strata (Wellington Flats core) to strata that indicate deposition on a relatively more distal, storm-dominated ramp (Tully core). The Sinbad Member, along with the upper part of the underlying Black Dragon Member and the lower part of the overlying Torrey Member (Moenkopi Formation), are composed of ten carbonate, siliciclastic and mixed carbonate/siliciclastic facies deposited on a west-facing ramp/shelf that reached maximum flooding during Smithian time. Individual beds and facies display a large degree of lateral homogeneity and regional persistence in the study area. The Wellington Flats core contains the three units characteristic of outcropping Sinbad Limestone: a basal skeletal unit, a middle peloidal unit, and an upper, oolitic dolomite unit. The more offshore Tully core is composed of skeletal grainstone, with fewer shallow-water carbonate and siliciclastic deposits. Discontinuity surfaces (hardgrounds, firmgrounds, and change surfaces) are common and indicate that sedimentation was punctuated by short-lived hiatuses accompanied by cementation, scour, and/or encrustation of the sediment-water interface. The Black Dragon, Sinbad, and lower Torrey Members represent at least one 3rd-order depositional sequence bounded below by the Tr-1 unconformity and above by lowstand deposits in the middle Torrey Member. Amalgamated fluvial channels in the middle of the Black Dragon Member may represent an additional 3rd-order sequence boundary that separates a Greisbachian sequence (lower Black Dragon Member) from the Smithian sequence (upper Black Dragon through lower Torrey members), but this is unsubstantiated by biostratigraphic data at present. Diagenesis is strongly controlled by facies. Diagenetic elements include marine fibrous calcite cements, micritized grains, compaction, dissolution and neomorphism of aragonite grains, meteoric cements, pressure dissolution, and dolomitization. The paragenetic sequence progresses from marine to meteoric to burial. Marine and meteoric cements occlude much of the depositional porosity, which ranges from 0 to 10 % in the sample interval. The best reservoir qualities in core (1.0 md) occur in grainstones and quartz-siltstones. Although its relative thinness precludes it from being a major producer, the Sinbad Limestone Member of the Moenkopi Formation bears potential for modest future oil production.
37
Erturk, Mehmet Cihan. "Production Performance Analysis Of Coal Bed Methane, Shale Gas, Andtight Gas Reservoirs With Different Well Trajectories And Completiontechniques." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615510/index.pdf.
Full textAbstract:
The large amount of produced oil and gas come from conventional resources all over the world and
these resources are being depleted rapidly. This fact and the increasing oil and gas prices force the
producing countries to find and search for new methods to recover more oil and gas. In order to meet
the demand, the oil and gas industry has been turning towards to unconventional oil and gas reservoirs
which become more popular every passing day. In recent years, they are seriously considered as
supplementary to the conventional resources although these reservoirs cannot be produced at an
economic rate or cannot produce economic volumes of oil and gas without assistance from massive
stimulation treatments, special recovery processes or advanced technologies.
The vast increase in demand for petroleum and gas has encouraged the new technological development
and implementation. A wide range of technologies have been developed and deployed since
1980. With the wellbore technology, it is possible to make use of highly deviated wellbores, extended
reach drilling, horizontal wells, multilateral wells and so on. All of the new technologies and a large
number of new innovations have allowed development of increasingly complex economically
marginal fields where shale gas and coal bed methane are found.
In this study, primary target is to compare different production methods in order to obtain better well
performance and improved production from different types of reservoirs. It is also be given some
technical information regarding the challenges such as hydraulic fracturing and multilateral well
configuration of the unconventional gas reservoir modeling and simulation. With the help of advances
in algorithms, computer power, and integrated software, it is possible to apply and analyze the effect
of the different well trajectories such as vertical, horizontal, and multilateral well on the future
production performance of coal bed methane, shale gas, and tight gas reservoirs. A commercial
simulator will be used to run the simulations and achieve the best-case scenarios. The study will lead
the determination of optimum production methods for three different reservoirs that are explained
above under the various circumstances and the understanding the production characteristic and profile
of unconventional gas systems.
38
Navarro, Fabiano Cabañas [UNESP]. "Influência da petrografia sobre a anisotropia à tensão de compressão e dilatação térmica de rochas ornamentais." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/103006.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Considerando um conjunto de 21 tipos de rochas utilizadas como revestimento e subdivididas em quatro conjuntos por afinidade da composição mineral (rochas carbonáticas, quartzosas, feldspáticas e quartzo-feldspáticas) foram realizados ensaios tecnológicos para a determinação do coeficiente de dilatação térmica linear e da resistência à compressão uniaxial, bem como a anisotropia dessas propriedades. Os dados tecnológicos obtidos foram correlacionados com informações petrográficas qualitativas e quantitativas referentes à composição mineral, variações texturais e estruturais determinadas em seções ortogonais entre si a partir de um sistema de referência (xyz) baseado na foliação e lineação macroscopicamente visíveis. A análise integrada dos dados utilizando estatística convencional e multivariada procurou apontar as variáveis petrográficas mais relevantes para as duas propriedades tecnológicas enfocadas e suas respectivas anisotropias. A dilatação térmica e sua anisotropia são influenciadas principalmente pela composição mineral e pela orientação preferencial dos minerais embora as microfissuras desempenhem papel importante em alguns casos. A tensão de compressão mostra sua variabilidade e anisotropia influenciadas pela granulação média, tipos de contatos minerais predominantes e padrões de microfissuras mais ou menos definidos por influência da foliação presente. Constatou-se que no conjunto analisado a presença da foliação não implica necessariamente em anisotropia das duas propriedades estudadas.
The anisotropy of thermal expansion coefficient and compressive tensile strength were determined for 21 commercially used stones gathered in four set according the main mineral composition named carbonatic, quartz-rich, feldspar-rich and quartz-feldspar-rich rocks. Using a coordinate reference system (xyz) based on the macroscopic visible foliation and lineation the samples were submitted to normalized laboratorial analyses for determination of the both technological properties and the petrographical features such as mineral composition, texture and fabric. Additionally was carried out measurements of weathered area and microcrack quantification by image analysis and texture quantification by U-stage methods. In order to understand the relationship between the anisotropy measured and petrographical data it was applied traditional and multivariate statistical analysis. The results pointed to the great significance of mineral composition and the crystallographic preferred orientation for thermal expansion and respective anisotropy, especially to monomineralic and/or foliated rocks, in spite of some cases microcracks play this role. The compressive strength is mainly controlled by a complex interaction between grain size distribution, grain boundary and microcrack patterns related or not to foliation.
39
Faßmer, Kathrin [Verfasser]. "Petrological analyses and Lu-Hf geochronology of subducted continental and oceanic crust from different locations in the upper and lower plate of the Caledonian Orogen / Kathrin Faßmer." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1207923613/34.
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SILVA, Andrezza Sousa. "Fatores controladores dos aspectos texturais em rochas siliciclásticas deformadas por bandas cataclásticas." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1596.
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A Bacia Rio do Peixe (BRP) apresenta diversas estruturas rúpteis, dentre elas as bandas de deformação, que podem controlar as propriedades petrofísicas e aspectos texturais das rochas. Portanto, o objetivo deste trabalho é identificar os efeitos causados pelos diferentes tipos de bandas de deformação cataclásticas, em função da cinemática, sobre os aspectos texturais, distribuição de tamanho de grãos e poros, bem como porosidade em arenitos conglomeráticos. As propriedades dos grãos e dos poros foram extraídas através da análise de imagens em seções delgadas no Avizo Fire 8.1. No total foram analisadas 23 amostras, 19 com bandas de deformação (CB) com orientação definida (NW, NE, NS e EW), 2 amostras deformadas, porém sem bandas (SB) e 2 amostras da rocha hospedeira (ND). As rochas deformadas (CB e SB), apresentam redução no tamanho de grãos e pequeno acréscimo nos valores dos aspectos texturais em comparação a rocha não deformada (ND). Em relação à porosidade foi encontrada redução de 66% nas amostras CB e acréscimo de 13% nas SB. Ambos agrupamentos possuem maior conexão de grãos, permitindo o surgimento da macroporosidade, que não havia sido detectada nas amostras ND. Dentre as amostras com banda de deformação e cinemática definida, a rochas associadas ao sistema transcorrente dextral, de direção NW, possuem maior redução de diâmetro de grão, e menor redução de porosidade, cerca de 29%. As amostras com bandas de deformação NE e NS, formadas por cinemática transtensiva, são as amostras nas quais houve a menor quebra dos grãos, entretanto caracterizam-se pela presença de porosidade por fraturamento de grãos, gerando altos picos de macroporosidade. As amostras oriundas do sistema distensivo de direção EW possuem segunda maior redução de grãos, maior redução de porosidade e ausência de macroporosidade. Os aspectos texturais (circularidade, convexidade e razão de aspecto) das amostras com banda (NW, NE, NS e EW) é dependente da intensidade de cisalhamento provocado por diferentes sistemas deformacionais, quanto mais intenso mais cominuído será o grão, e consequentemente mais convexo, circular e menos alongado. Logo, é possível observar que a cinemática e a presença de bandas de deformação exercem controle sobre os aspectos texturais e petrofísicos dos arenitos conglomeráticos da Formação Antenor Navarro. E esse controle é definido pela compactação da rocha, rearranjo dos grãos, intensidade da catáclase, presença de fraturamento de grãos e cinemática atuante.
The Rio do Peixe Basin (RPB) presents several rump structures, among them the deformation bands, which can control the petrophysical properties and textured aspects of the rocks. Therefore, the objective of this work is to identify the effects caused by the different types of cataclastic deformation bands, as a function of kinematics, on the textural aspects, grain and pore size distribution, as well as porosity in conglomeratic sandstones. The grain and pore properties were extracted by thin section image analysis in Avizo Fire 8.1. In total, 23 specimens were analyzed, 19 with deformation bands (CB) with defined orientation (NW, NE, NS and EW), 2 deformed samples, but without bands (SB) and 2 samples of host rock (ND). The deformed rocks (CB and SB), present a reduction in grain size and small increase in the values of the textured aspects in comparison to the non-deformed rock (ND). In relation to the porosity, a reduction of 66% was found in the CB samples and a 13% increase in the SB. Both clusters have a larger grain connection, allowing the appearance of macroporosity, which had not been detected in the ND samples. Among the samples with deformation band and defined kinematics, the rocks associated to the dextral transcurrent system, NW direction, have a larger reduction of grain diameter, and a smaller reduction of porosity, about 29%. The samples with NE and NS deformation bands, formed by transtensive kinematics, are the samples with the lowest grain breakage. However, they are characterized by the presence of porosity by grain fracturing, generating high peaks of macroporosity. The samples from the EW steering distance system have the second largest grain reduction, greater reduction of porosity and absence of macroporosity. The textural aspects (roundness, convexity and aspect ratio) of the banded samples (NW, NE, NS and EW) are dependent on the shear strength caused by different deformation systems, the more intense the grain is, the more convex, circular and less elongated. Therefore, it is possible to observe that kinematics and the presence of deformation bands exert control over the texture and petrophysical aspects of the conglomeratic sandstones of the Antenor Navarro Formation. And this control is defined by the rock compaction, rearrangement of the grains, the intensity of the catachase, presence of grain fracture and active kinematics.
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Cruz, Matthew. "Field Mapping Investigation and Geochemical Analysis of Volcanic Units within the Dinner Creek Tuff Eruptive Center, Malheur County, Eastern Oregon." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3837.
Full textAbstract:
The Dinner Creek Tuff is a mid-Miocene rhyolitic to dacitic ignimbrite, consisting of four cooling units with 40Ar/39Ar ages 16--15 Ma. Previous geologists have suspected that the source of the tuff is located in northwestern Malheur County, eastern Oregon. This broad area is called the Dinner Creek Tuff Eruptive Center.
This thesis summarizes field work, XRF/ICP-MS geochemistry, thin section petrography, and SEM feldspar analysis from the summers of 2015 and 2016. The main purpose of this study is to identify sources for the Dinner Creek Tuff units within the Dinner Creek Tuff Eruptive Center. The secondary purpose is to map lava flows that pre-date and post-date the Dinner Creek Tuff, and correlate them with regionally extensive volcanic units.
Two volcanic centers related to the Dinner Creek Tuff were identified. The southern volcanic center, centered at Castle Rock, is a caldera and source of the Dinner Creek Tuff unit 1 (DIT1). Rheomorphic, densely welded DIT1 is over 300 m thick along the east side of Castle Rock. The northwestern margin of the caldera has been uplifted along faults, showing vertically foliated tuff dikes and associated mega-breccia deposits. Up to 200 m of incipiently welded tuffs, and fluvial volcanoclastic sediments were deposited on the caldera floor, which has been uplifted due to resurgence and regional extension, creating the complex structural relationships between the volcanic units.
The northern volcanic center is located at Ironside Mountain, where densely welded rheomorphic Dinner Creek Tuff unit 2 (DIT2) is exposed in outcrops over 600 m thick. The top of the DIT2 consists of glassy, moderately welded tuff. Sources for the DIT2 are tuff dikes along the south and western flanks of Ironside Mountain. The thick deposits of DIT2 at Ironside Mountain indicate that the mountain is an uplifted caldera, herein named the Ironside Mountain caldera. Uplift may have been due to resurgence, but it is most likely due to normal faulting along the Border Fault, a major regional normal fault that strikes across the northern margin of the caldera.
Pre-Dinner Creek Tuff lava flows occur throughout the study area, and can be correlated with the Strawberry Volcanics and the Basalt of Malheur Gorge. A distinct lava flow, herein called the Ring Butte trachy-basalt occurs within the center of the study area, and is distinct from regional lava flows. Following the eruptions of the Dinner Creek Tuff units 1 & 2, aphyric basaltic-andesite and icelandite intrude into, and overlie the intra-caldera tuffs and caldera floor sediments at both calderas. These aphyric lavas are similar in appearance and stratigraphic position with the regionally extensive Hunter Creek basalt. Porphyritic olivine basalt overlies the aphyric Hunter Creek basalt at the Castle Rock caldera. This porphyritic lava is similar in appearance and major/trace element geochemistry to the regional Tim's Peak basalt.
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Pickett, Clarence. "A sedimentary facies analysis of the >2.8 Ga Beniah and Bell Lake formations, Slave Province, Northwest Territories." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2002. http://theses.uqac.ca.
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Isom, Shelby Lee. "Compositional and Physical Gradients in the Magmas of the Devine Canyon Tuff, Eastern Oregon| Constraints for Evolution Models of Voluminous High-silica Rhyolites." Thesis, Portland State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10606618.
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Large-volume silicic ignimbrites erupt from reservoirs that vary in composition, temperature, volatile content and crystallinity. The 9.7 Ma Devine Canyon Tuff (DCT) of eastern Oregon is a large-volume (>250 km3), compositionally zoned and variably welded ignimbrite. The ignimbrite exhibits heterogeneous trace element compositions, variable volatile content and crystallinity. These observations were utilized in the investigation into the generation, accumulation and evolution of the magmas composing the DCT. Building off previous research, pumices were selected from the range of trace element compositions and analyzed with respect to crystallinity, mineral abundances and assemblages. The DCT displays a gradational trace element enrichment and decrease in crystallinity from least evolved, dacite, at ∼22% crystals to most evolved high-silica rhyolite at 3% crystals. Two distinct mineral populations of feldspar and clinopyroxene were identified in previous work, one belonging to the rhyolitic magma and the other to the dacitic magma. Volatile content derived from melt inclusion Fourier Transform Infrared (FTIR) spectrometer analysis revealed an increase in water content from 1.2 to 3.7 wt.% in the most evolved rhyolite. The DCT exhibits low and variable δ18 O signatures, 4.52‰ to 5.76‰, based on δ 18O values measured on quartz and sanidine. Low δ18O signatures of all DCT rhyolites suggest the incorporation of hydrothermally altered crust into the melt. Furthermore, quartz phenocrysts from all high-silica rhyolite groups display dark oscillatory zoned cores and Ti-rich bright rims.
These data provide insight into how these magmas were generated and subsequently stored in the crust. Commonalities of petrographic and compositional features among rhyolites, especially the zoning characteristics of quartz phenocrysts, exclude the possibility of storage and evolution in multiple reservoirs. Envisioning a scenario where all magmas are stored within a single reservoir prior to eruption and assuming rhyolites A and D are the product of partial melting. The mixing of A and D rhyolites produced rhyolite B, and subsequent mixing of intermediate rhyolite B and end-member rhyolite D generated rhyolite C. However, some trace element inconsistencies, between mixing model and observed intermediate rhyolites suggest a secondary process. Post mixing, rhyolites B and C require some modification by fractional crystallization to account for LREE and other inconsistencies between mixed models and observed rhyolites. Finally, the origin of the dacite is likely through mixing of group D rhyolite and an intrusive fractionated basalt, which could have led to the eruption of the Devine Canyon Tuff.
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Grand'homme, Alexis. "Etude de la monazite comme chronomètre et traceur géochimique des minéralisations hydrothermales : Approche expérimentale et analyses de monazites de veines alpines." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAU004/document.
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La monazite est présente comme minéral accessoire dans la plupart des environnements géologiques. Elle est souvent riche en U et Th, n’incorpore pas (ou peu) de Pb initial et son système isotopique (U-Th-Pb) est résistant à la diffusion dans la majorité des conditions crustales, ce qui en fait un chronomètre très attractif. De plus, elle constitue la principale source de Th et une des principales sources de terres rares (REE) contenus dans la croûte terrestre. En présence de fluide, la monazite peut recristalliser par un processus de dissolution-précipitation couplée, avec une composition chimique et/ou isotopique différente de la monazite initiale. Ces recristallisations impliquent alors une redistribution des éléments contenus par la monazite (REE, Th, U, Pb) et la compréhension de la mobilité de ces éléments stratégiques est cruciale pour leurs aspects économiques (ressources en lanthanides et actinides) et environnementaux (contexte de stockage des déchets).Cette thèse vise à étudier le comportement de la monazite lors des interactions fluide-monazite et son potentiel comme traceur chronomètre et traceur géochimique des minéralisations hydrothermales. Pour cela une approche pluridisciplinaire a été adoptée, combinant minéralogie, pétrologie expérimentale, géochronologie, et tectonique. Les travaux présentés s’organisent en deux parties: l’une concernant la datation de monazites hydrothermales de fentes alpines, et l’autre des expériences d’altérations hydrothermales en laboratoire.Une quarantaine de cristaux de monazite et une dizaine de cristaux de xénotime ont été collectés dans des fentes alpines (veines hydrothermales se formant durant l’exhumation) des domaines externes (Argentera, Belledonne et Mont-Blanc) et internes (zone Briançonnaise). La datation U-Th-Pb in-situ par LA-ICP-MS a permis de mieux contraindre l’âge et la durée des circulations hydrothermales pendant les épisodes de déformation tardifs liés à l’exhumation des Alpes occidentales. Les analyses d’inclusions fluides dans la monazite couplées à des âges traces de fission sur zircons ont apporté de nouvelles contraintes sur le gradient géothermique induit par les circulations fluides dans les veines hydrothermales. L’analyse systématique des produits expérimentaux (monazite et fluide) de 18 expériences hydrothermales a permis de confirmer la mobilité des éléments comme l’uranium ou les terres rares lourdes lors des réactions hydrothermales. L’étude à l’échelle nanométrique des domaines de monazite recristallisée a mis en évidence un nouveau mécanisme de remplacement caractérisé par la propagation du front de réaction à l’aide de nano-pores et nano-fractures. Ce mécanisme conduit à un remplacement anisotrope et à un mélange de nano-domaines de monazite primaire et recristallisée. Ces observations ont des implications majeures pour le stockage des déchets radioactifs ou en géochronologie pour expliquer les perturbations des âges monazites ayant réagi avec un fluide dans les milieux hydrothermaux ou métamorphiquesMonazite is commonly found in most of geological environments. Monazite can be rich in uranium and thorium, does not incorporate lead, and its isotopic (U-Th-Pb) system is very robust to diffusion in most of crustal conditions, which makes it a very attractive chronometer. In addition, it represents the main source of thorium and a major source of rare earth elements (REE), in the crust. During fluid-monazite interaction, monazite can recrystallize by a coupled dissolution-precipitation process, with a chemical/isotopic composition different from the initial monazite. These recrystallizations involve a redistribution of the elements contained in monazite (REE, Th, U, Pb) and understanding of the mobility of these strategic elements is crucial for their economic (lanthanides resources and actinides) and environmental (storage of radioactive waste) aspects.The aim of this thesis is to investigate the behaviour of monazite during fluid-monazite interactions and its potential as chronometer and geochemical tracer of fluid mineralization, via a multi-disciplinary approach including mineralogy, experimental petrology, geochronology and tectonic. The work presented here is organized in two parts: one on Alpine hydrothermal monazite dating and the other on the results of hydrothermal alteration experiments in laboratory.About forty monazite and ten xenotime crystals were collected in Alpine clefts (hydrothermal veins formed during exhumation) of the external (Argentera, Belledonne, Mont-Blanc) and the internal (Briançonnais Zone) domains. The LA-ICP-MS in-situ U-Th-Pb dating allowed to better constrain the age and duration of hydrothermal circulation during the late deformation stages related to the exhumation of the western Alps. The fluid inclusion analysis of monazite crystals coupled with zircon fission-track dating have brought new constrains on the geothermal gradient induced by fluid circulations in the hydrothermal veins. Systematic analysis of experimental products (monazite and fluid) of 18 experiments confirmed the mobility of elements such as uranium or heavy REE during hydrothermal reactions. The nanoscale study of monazite recrystallized domains showed a new replacement mechanism characterized by the propagation of the reaction front through nano-pores and nano-fractures. This mechanism leads to anisotropic replacement and a mixture of nano-domains of primary and recrystallized monazite. These observations have major implications for the storage of radioactive waste or in geochronology to explain the disturbances of monazite ages that have reacted with fluid in hydrothermal or metamorphic environments
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Fragomeni, Paulo Roberto Pizarro. "Levantamento e estudo das ocorrências de grafita do Distrito Grafitífero Aracoiába-Baturité, CE." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8824.
Full textAbstract:
O Distrito Grafitífero Aracoiába-Baturité apresenta depósitos do tipo gnaisse grafitoso (minério disseminado) e veio (minério maciço) com diferentes origens genéticas e com características físicas e ambientes geológicos de formação próprios. O minério tipo gnaisse grafitoso é de origem sedimentar, singenético, com teores de 1,5 a 8% de C, que se distribuem ao longo de duas extensas faixas paralelas, hospedadas na Subunidade Baturité, que constitui um importante metalotecto regional. A associação de grafita metamórfica disseminada em metassedimentos da Sequência Acarápe constitui um geoindicador de antiga bacia sedimentar neoproterozóica e, também, pode ser considerado como zona de geosutura resultante do subsequente fechamento de um oceano primitivo. As rochas desta subunidade correspondem na paleogeografia da Sequência Acarápe aos fácies de sopé de talude e de planície abissal. O minério tipo veio (fluido depositado) é epigenético e, com teores entre 20% e 70% de C, forma corpos tabulares e bolsões, controlados em escala local por estruturas de alívio (falhas, fraturas, zonas de contato, eixos de dobras etc.) que permitiram a percolação de soluções penumatolíticas relacionadas ao corpo plutônico de Pedra Aguda. As variações dos valores das relações entre isótopos estáveis de carbono (δ13C) na grafita do minério disseminado são de -26,72 a -23,52 e do minério maciço de -27,03 a -20,83, revelando sinal de atividades biológicas (bioassinaturas) e permitem afirmar que a grafita das amostras acima são derivadas de matéria orgânica. Foram apresentados os principais guias de prospecção para grafita e testados os seguintes métodos geofísicos: Eletro-Resistividade; GPR - Ground Penetrating Radar; Magnetometria; VLF (Very Low Frequency); e Polarização Induzida Espectral (IPS) / Resistividade (ER). A conjugação dos métodos de Polarização Induzida Espectral (IPS) e Eletro Resistividade (ER) foi o que demonstrou a melhor eficiência. Com relação à determinação do teor de carbono por termogravimetria (ATG), que é o método mais utilizado para este elemento. Verificou-se, que as faixas de queima atribuídas ao carbono no minério do Distrito de Aracoiába-Baturité (340 a 570C e de 570 a 1050C) eram diferentes das faixas do minério de Minas Gerais (350C a 650C e 650C a 1.050C). Esta constatação indica a necessidade de se determinar previamente as faixas de temperatura para cada região pesquisada.The Aracoiába-Baturité Graphite-bearing District has graphitic gneiss deposits (disseminated ore) and vein (solid ore) with different genetic origins and their own physical characteristics and geological environments. The graphite gneiss ore is of sedimentary, syngenetic origin, with 1.5% to 8% C content, which is distributed along two long parallel belts, hosted in the Baturité Sub-unit, which consists of a major regional metallotect. The association of metamorphic graphite disseminated in metasediments of the Acarápe Sequence consists of a geoindicator of an old Neo-Proterozoic sedimentary basin and also can be considered a geosuture zone, the result of the subsequent closing of a primitive ocean. The rocks of this subunit correspond in the paleogeography of the Acarápe Sequence to the facies of the bottom of a slope and of an abyssal plain. The vein ore (deposited fluid) is epigenetic and, with C contents of between 20% and 70%, forms tabular bodies and pockets, controlled on a local scale by relief structures (faults, fractures, contact zones, fold axes, etc.), which allowed seepage of pneumatolithic solutions relating to the plutonic body of Pedra Aguda. The variations in the values of the ratios between stable carbon isotopes (δ13C) in the graphite of the disseminated ore are -26.72 to -23.52 and of the solid ore -27.03 to -20.83, showing a sign of biological activities (biosignatures), and it can be said that the graphite of the above samples is derived from organic matter. The main prospecting guides for graphite were presented and the following geophysical methods tested: Electro-resistivity (ER); Ground Penetrating Radar (GPR); Magnetometry; Very Low Frequency (VLF); and Spectral Induced Polarization (SIP) / Electro-resistivity (ER). It was found that the combination of the Spectral Induced Polarization (SIP) and Electro-resistivity (ER) methods proved the most efficient. In relation to determining the carbon content using thermogravimetry (TG), which is the most commonly used method for this element, it was found that the bands of burning attributed to the carbon in the ore in the Aracoiába-Baturité District (340 to 570C and from 570oC to 1050C) were different from the bands of the ore in Minas Gerais (350C to 650C and 650C to 1050C). This finding suggests the need to determine beforehand the temperature ranges for each region studied.
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Yang, Xin-She. "Mathematical modelling of compaction and diagenesis in sedimentary basins." Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:0bdc6c43-4534-4f08-97e2-8a33d6b13e61.
Full textAbstract:
Sedimentary basins form when water-borne sediments in shallow seas are deposited over periods of millions of years. Sediments compact under their own weight, causing the expulsion of pore water. If this expulsion is sufficiently slow, overpressuring can result, a phenomenon which is of concern in oil drilling operations. The competition between pore water expulsion and burial is complicated by a variety of factors, which include diagenesis (clay dewatering), and different modes (elastic or viscous) of rheological deformation via compaction and pressure solution, which may also include hysteresis in the constitutive behaviours. This thesis is concerned with models which can describe the evolution of porosity and pore pressure in sedimentary basins. We begin by analysing the simplest case of poroelastic compaction which in a 1-D case results in a nonlinear diffusion equation, controlled principally by a dimensionless parameter lambda, which is the ratio of the hydraulic conductivity to the sedimentation rate. We provide analytic and numerical results for both large and small lambda in Chapter 3 and Chapter 4. We then put a more realistic rheological relation with hysteresis into the model and investigate its effects during loading and unloading in Chapter 5. A discontinuous porosity profile may occur if the unloaded system is reloaded. We pursue the model further by considering diagenesis as a dehydration model in Chapter 6, then we extend it to a more realistic dissolution-precipitation reaction-transport model in Chapter 7 by including most of the known physics and chemistry derived from experimental studies. We eventually derive a viscous compaction model for pressure solution in sedimentary basins in Chapter 8, and show how the model suggests radically different behaviours in the distinct limits of slow and fast compaction. When lambda << 1, compaction is limited to a basal boundary layer. When lambda >> 1, compaction occurs throughout the basin, and the basic equilibrium solution near the surface is a near parabolic profile of porosity. But it is only valid to a finite depth where the permeability has decreased sufficiently, and a transition occurs, marking a switch from a normally pressured environment to one with high pore pressures.
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Standley, Carl Eldon. "Banda Forearc Metamorphic Rocks Accreted to the Australian Continental Margin: Detailed Analysis of the Lolotoi Complex of East Timor." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1304.
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Petrologic, structural and age investigations of the Lolotoi Complex of East Timor indicate that it is part of a group of thin metamorphic klippen found throughout the region that were detached from the Banda forearc and accreted to the NW Australian continental margin during Late Miocene to Present arc-continent collision. Metamorphic rock types are dominated by (in order of greatest to least abundance), greenschist, graphitic phyllite, quartz-mica schist, amphibolite and pelitic schist. Mineral, whole rock, and trace element geochemical analyses of metabasites indicate that protolith compositions are consistent with tholeiitic basalt and basaltic andesite with mixed MORB and oceanic arc affinities. Metapelitic schist compositions are consistent with mafic to intermediate oceanic to continental arc provenance. Geothermobarometric calculations show peak metamorphic temperatures in pelitic rocks range from 530°C to 610°C for garnet-biotite pairs and peak pressures of 5 to 8 kbar for garnet-aluminosilicate-quartz-plagioclase assemblages. Analyses of amphibole in amphibolites yield temperatures of 550°C to 650°C and pressures of 6 to 7 kbar. Lu-Hf analyses performed on garnet samples from two massifs in East Timor yielded four ages with a mean of 45.36 ± 0.63 Ma, which is interpreted to represent the approximate age of peak metamorphism. Detrital zircons from one amphibolite sample in East Timor yields a bimodal U-Pb age distribution of 560 Ma and 80 Ma, indicating deposition occurred after the 80 Ma closure of the zircon grains. The sequence of deformation as indicated by field measurements is similar to that reported from other klippen throughout the Timor region. Contact relationships with adjacent units indicate that the metamorphic terrane is in thrust contact with underlying Gondwana Sequence rocks. Overlying the metamorphic rocks are Asian affinity volcanic and sedimentary cover units found mostly in normal fault contact on the edges of Lolotoi Complex klippen. Geochemical, age, petrological and structural data imply the Lolotoi Complex formed part of the eastern Great Indonesian arc, which began to collapse in the Eocene, was incorporated into the Banda arc in the Miocene, and accreted to the Austrailian continental margin from Pliocene to Present.
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Bouenitela, Vicky Tendresse Télange. "Le domaine paléoprotérozoïque (éburnéen) de la chaîne du Mayombe (Congo-Brazzaville) : origine et évolution tectono-métamorphique." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1B008/document.
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La chaîne du Mayombe constitue la portion congolaise du système orogénique « Araçuaï-West Congo » qui se répartit entre la marge orientale du Brésil et la marge occidentale de l’Afrique centrale. Elle s’allonge parallèlement au littoral atlantique suivant la direction NW-SE. En tenant compte des données géochronologiques, elle se subdivise en deux domaines lithostratigraphiques : (i) le domaine paléoprotérozoïque et (ii) le domaine néoprotérozoïque. Le domaine paléoprotérozoique de la chaîne du Mayombe correspond à la partie interne de la chaîne et se caractérise par la co-existence des roches d’origine sédimentaire et magmatique déformées et métamorphisées à des degrés variés. Ces roches se répartissent en trois principaux groupes lithologiques : (i) le Groupe de la Loémé, (ii) le Groupe de la Loukoula et (iii) le Groupe de la Bikossi. L’analyse structurale des Groupes de la Loémé et de la Loukoula montre que ceux-ci sont plissés et fracturés. Dans le Groupe de la Loémé les plis présentent des axes qui s’orientent dans les directions NE-SW, NNE-SSW et N-S tandis que dans le Groupe de la Loukoula, le plissement se fait suivant la direction NE-SW. Le Groupe de la Bikossi se caractérise par des plis qui s’orientent dans les directions identifiées dans les précédants Groupes. L’étude géochimique réalisée sur les échantillons provenant du domaine paléoprotérozoïque de la chaîne du Mayombe montre que ce dernier est hétérogénique c’est-à-dire qu’il implique des terrains d’origine et de lithologie variées. La caractérisation pétrologique des ensembles lithologiques des groupes de la Loémé et de la Loukoula montre que ceux-ci sont affectés par au moins deux événements métamorphiques distincts qui se superposent. Le premier événement se traduit par des paragenèses à grenat-biotite-oligoclase dans les métapélites et par le développement de la hornblende brune dans les métabasites permettant ainsi de situer le contexte d’évolution dans le faciès des amphibolites. Le second événement s’enregistre de façon différente dans le Groupe de la Loémé et dans le Groupe de la Loukoula. Il se traduit respectivement par des assemblages à grenat-biotite-oligoclase dans les formtaions du Groupe de la Loémé et par une paragenèse à chlorite-albite-épidote dans le Groupe de la Loukoula. Les échantillons rattachés au Groupe de la Bikossi ne présentent que les traces d’un seul événement métamorphique marqué par les paragenèses à grenat-biotite-muscovite et grenat-chloritoïde-chlorite avec une température oscillant entre 510-568°C pour une pression d’environ 8 kbar. La datation U-Pb sur zircons a permis de : (i) définir les sources des matériaux détritiques ayant constitué les bassins évoluant de l’Archéen au Protérozoïque (3300-1500) ; (ii) de confirmer l’âge paléoprotérozoïque (2070-2040 Ma) du magmatisme éburnéen ainsi que l’âge néoprotérozoïque (925 Ma) des granites de type Mfoubou et Mont Kanda et (iii) mettre en évidence des perturbations du système isotopique U-Pb des zircons à 642 ± 36 Ma et 539 ± 18 Ma. Les analyses 40Ar-39Ar sur biotite, muscovite et amphibole des échantillons du domaine occidental de la chaîne du Mayombe ont fourni des âges qui situent l’événement tectono-thermique pan-africain entre 615 Ma et 496 MaThe Mayombe belt is the congolese part of the Araçuaï-West Congo belt system which extend from eastern margin of Brazil to western margin of central Africa. It runs parallel to the Atlantic coastline with NW-SE trend. Considering geochronological data, it is subdivided into two lithostratigraphic domains : (i) the Paleoproterozoic domain and (ii) the Neoproterozoic domain. The Paleoproterozoic domain of the Mayombe range corresponds to the inner part of the belt and is characterized by the coexistence of para and orthoderived rocks deformed and metamorphosed to varying degrees. These rocks are distributed among the three main lithological Groups : (i) the Loémé Group, (ii) the Loukoula Group and (iii) the Bikossi Group. Structural analysis of Loémé and Loukoula Groups shows folded and fractured stuctures. In the Loémé Group, folds trend NE-SW, NNE-SSW and N-S while in the Loukoula Group, the main shortening trends NE-SW. The Bikossi Group is characterized by folds oriented in the directions identified in the preceding Groups. The geochemical study carried out on samples from the Paleoproterozoic domain of the Mayombe belt shows that the latter is heterogeneous, by involving rocks of various origin and lithology. The petrological characterization of Loémé and Loukoula Groups shows that they are affected by at least two distinct metamorphic events that overlap. The first event is characterized by garnet-biotite-oligoclase parageneses in metapelites and by the development of brown hornblende in metabasites, thus allowing the evolution context to be situated in the amphibolite facies. The second event is recorded differently in Loémé Group and Loukoula Group. It consits respectively in garnet-biotite-oligoclase assemblages in the Loemé Group and in chlorite-albite-epidote paragenesis in the Loukoula Group. Samples from Bikossi Group present only traces of a single metamorphic event marked by garnet-biotite-muscovite and garnet-chloritoid-chlorite parageneses whose temperature is estimated at 510-568°C for 8 kbar of pressure. U-Pb dating of zircons allows to : (i) define the Archean-Paleoproterozoic (3300-1500Ma) sources of metasedimentary rocks (ii) confirm Paleoproterozoic (2070-2040 Ma) age of Eburnean magmatism and Neoproterozoic (925 Ma) Mfoubou and Mont Kanda type magmatism and (iii) to highlight the perturbations of zircons U-Pb isotopic system at 642 ± 36 Ma and 539 ± 18 Ma. The 40Ar-39Ar analyzes on biotite, muscovite and amphibole from samples of the western domain of Mayombe betl provided since the age range of Pan-African tectono-thermal event at 615-496 Ma
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Boulanger, Marine. "Le devenir des liquides au sein de la croûte océanique des dorsales à expansion lente : nouveaux apports de l'étude d'Atlantis Bank (dorsale Sud-Ouest Indienne)." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0030.
Full textAbstract:
Les processus magmatiques qui régissent l'accrétion crustale au niveau des dorsales médio-océaniques à expansion lente restent à l'heure actuelle mal contraints. Parmi les processus potentiellement impliqués dans l'évolution des réservoirs de magma de la croûte inférieure, les réactions associées à des écoulements poreux réactifs au travers de bouillies cristallines - ou mush - tendent à supplanter les processus classiques de cristallisation simple des magmas. La part de ces processus dans la formation des gabbros cumulatifs de base de croûte est dépendante des modes de migration des liquides, qui sont eux-mêmes corrélés à la géométrie des réservoirs considérés. En combinant des études structurales, pétrographiques et géochimiques à haute résolution de sections in situ forées dans un corps complexe océanique de la dorsale Sud-Ouest indienne, j'ai pu apporter de nouvelles contraintes sur les modes de formation et d'évolution des réservoirs magmatiques impliqués lors de l'accrétion crustale. Le modèle de réservoir développé est généralisable, au moins en partie, à d'autres portions de croûte inférieure océanique. Ce modèle, ainsi que les nouvelles contraintes de l'étude expérimentale couplée des processus de cristallisation, ouvre la voie vers de nouvelles quantifications des processus d'interaction liquides-roches dans la différenciation des lithologies gabbroïques, et de manière plus générale dans l'évolution des liquides magmatiques de la croûte océanique. Ces développements vont de pair avec l'évolution au cours des dernières décennies de la vision des systèmes magmatiques crustaux, passant de chambres magmatiques constituées de liquides vers des modèles de réservoirs magmatiques majoritairement constitués de mush cristallinsMagmatic processes that govern crustal accretion at mid-ocean ridges still need to be better constrained. Among the processes potentially involved in the evolution of the lower crust magma reservoirs, reactions associated with reactive porous flow through crystal mushes tend to be considered as one of the predominant processes together with simple crystallization of magmas. The share of these processes during magma differentiation is dependent on the modes of melt migration and is thus correlated to the geometry of the reservoirs considered. By combining high-resolution structural, petrographic and geochemical studies of in situ sections drilled in an oceanic core complex of the Southwest Indian Ridge, I was able to bring new constraints on the formation and evolution of magmatic reservoirs involved in crustal accretion. All or part of the igneous reservoir model developed herein can be applied to other sections of lower oceanic crust. This model, together with additional constraints obtained by the coupled experimental petrology study of crystallization processes, paves the way for new quantifications of the involvement of melt-rock reactions in the differentiation of gabbroic lithologies, and more generally in the evolution of melts within the oceanic crust. Those developments are consistent with the constant evolution in recent decades of the understanding of crustal magmatic systems, which shifted from melt-filled magma chambers to igneous reservoir models mostly composed of crystal mushes
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Coetzee, Grace. "Petrology and geochemistry of the Tjakastad (Barberton) ICDP cores." Thesis, 2014. http://hdl.handle.net/10539/14936.
Full textAbstract:
The Komati Formation of the Barberton Greenstone Belt is the type locality of the rock type known as Komatiites. Komatiites are ultramafic lavas that were generated and erupted mainly during the Archaean. They give insight into volcanism on the early Earth as well as the nature of the mantle and melting processes. During 2010-2011 the International Continental Drilling Programme (ICDP) Barberton Project drilled two cores (BARB 1 and BARB 2) into the Komati Formation to obtain continuous sections of the komatiite strata. These cores were drilled to gain knowledge about the structure, textures, compositions, processes and contact relationships of komatiite flows, which could not be obtained from surface outcrop because of lack of continuity and relatively poor exposure. The drill holes also intersected a volcanic tumulus unit, the first of its type recognized in komatiite lava flows, allowing insight into the processes that created the tumulus and the processes responsible for creating the differentiated komatiite flows.
The core was logged in detail, revealing a variety of rock-types and styles of volcanism. The rock-types encountered range from massive and differentiated ultramafic komatiites, through komatiitic basalts to mafic basalts. Some minor later intrusions of gabbros and dolerite are also present. The komatiites and komatiitic basalts are extrusive lavas and represent continuous eruptive sequences. The gabbros are typically intrusive, but can represent late stage crystallization. Contact relationships are evident in the core, where they have not been eroded by overlying flows, and are used to distinguish 85 individual flows in BARB 1 and 65 in BARB 2. Chill margins are typically between 5 and 50 cm thick and brecciated contacts are usually 5- 15 cm thick where present. Only rare examples of original mineralogy (olivine and pyroxene) are preserved because of pervasive alteration of the rocks. Alteration minerals are serpentine, chlorite, tremolite and magnetite. Early serpentine veining was followed by later stage magnesite veining. The opaque minerals – chromite with secondary magnetite overgrowth – are mostly located at olivine grain boundaries.
The tumulus unit in the BARB 1 core was created by upward doming of the upper skin of a lava tube. The unit is 90 m thick and consists of five textural sections: basal cumulates, harrisite, pyroxene spinifex, gabbro-pyroxenite and a hyaloclastite unit that caps the sequence. The cumulates contain macrocrystic olivine grains that reach 15 mm in length; they are elongated and rounded, aligned in certain horizons and are tightly packed, with a maximum of 20 % matrix. The harrisite is a form of skeletal olivine (with crystals up to 5 cm in length) that grew upwards from the underlying cumulate layer. Between the skeletal olivine crystals are small (< 2 mm) crescent-shaped pyroxenes contained within the melt residue. Pyroxene grains in the spinifex lava reach 20 cm in length and are surrounded by a fine-grained matrix. The gabbro and pyroxenite layers contained within the spinifex layer are interpreted to represent the last stage of crystallization within the structure since they are chemically related to the tumulus and no chill margins are present between the gabbro and surrounding pyroxene spinifex. Both the spinifex and gabbro contain unaltered pyroxene crystals and the gabbro also contains relatively fresh plagioclase. The hyaloclastite breccia consists of fragmented fine-grained chill margin blocks derived from the upper crust of the lava tube. The fragments are surrounded and supported by a glassy shard-like matrix. Inflation processes are evident in the tumulus and gave rise to multiple layers of large elongated olivine cumulates together with the upward and outward bulging of the upper crust to form a hyaloclastite breccia. Chemically the tumulus exhibits a Fo93 olivine control. Fractionation processes are clear in MgO vs. depth, binary diagrams and REE plots. Element concentrations are between 1 and 11 times chondrite with a very small LREE enrichment.
Differentiated komatiite flows are composed of three lithologies: basal cumulates, olivine spinifex and chill margin zones. The cumulus olivines have a crystal size of 0.5-1 mm, are euhedral and enclosed by a 30 to 60 % melt component. The spinifex olivine forms random or parallel sheets on a centimetre scale and is completely altered to serpentine. Between the olivine spinifex are chemically more evolved pyroxene spinifex blades, which are smaller (millimetre to centimetre scale) and altered to a combination of serpentine-chlorite-tremolite. The fine-grained chill margins of the flows are typically 1-10 cm wide and in some cases contain contact breccias or hyaloclastites.
Three packages of differentiated komatiite flows occurring at several stratigraphic intervals where sampled in detail. The lowest package BARB 1 (89-118 m) exhibits chemical trends that are interpreted to indicate a combined crystallization control by olivine and pyroxene. This is evident in the rock compositions and by petrographic studies that reveal the presence of two cumulus phases. The chemical compositions of the other two differentiated packages, BARB1 (378-420 m) and BARB 2 (252-274 m) are controlled by crystallization or accumulation of Fo93 and Fo94, respectively. These packages have olivine cumulates which are surrounded in some cases by pyroxene oikocrysts. In some samples the pyroxenes have unaltered cores. The REE plots are well constrained between 2 and 9 times chondrite values, and have slight LREE enrichment.
The tumulus structure and differentiated flow packages BARB 1 (378-420 m) and BARB 2 (252-274 m) have similar mineralogies and compositions but contain different textures. This is attributed to the size of the tumulus in comparison to the differentiated flows and implies similar magma processes and origins for all three units. The BARB 1 (89-118 m) interval appears to have undergone slightly different processes, as indicated by the presence of the two cumulus phases. This package is also altered to a greater extent than the others and no unaltered pyroxene is present.