Thesis (Ph. D.)--University of Wisconsin. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [82]-84).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Six maps and diagrams on folded leaves in pocket. Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 380-389).

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Restricted until May 2005. Bibliography: leaves 145-153. Also available online.

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 88-99)

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 101-108)

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979. / Supervised by Elazar Uchupi. Vita. Includes bibliographical references (leaves 163-184).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 74-82).

Made available in DSpace on 2015-09-17T15:24:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-06-17. Added 1 bitstream(s) on 2015-09-17T15:47:49Z : No. of bitstreams: 1 000845972.pdf: 10093285 bytes, checksum: 4b3f81cedfdb7f2e6f2f0eabaf1a1822 (MD5) / A área de estudo se localiza nos Andes Centrais, ao sul da Deflexão de Abancay, Peru, inserida na província metalogenética (Andahuaylas-Yauri) relacionada ao Batólito de Abancay, que hospeda depósitos do tipo pórfiro-skarn de Fe-(Cu-Au) e depósitos filoneanos de Au. É constituída por sequências clásticas e carbonatadas de idades mesozóicas, intrudidas por plutons e stocks de monzonito e granodiorito que, por sua vez, são sobrepostos por rochas vulcânicas oligomiocênicas relacionadas com mineralização auroargentífera na porção sudeste da região. Neste trabalho apresenta-se um estudo do quadro geológico regional aliado à análise do padrão estrutural da região entre Sabaino e Santo Domingo, com a caracterização da cinemática de sistemas de falhas de cinco setores dessa área, onde ocorrem mineralizações, abrangendo medidas de 119 falhas mesoscópicas com estrias, a partir das quais obteve-se os tensores de esforços relacionados com o estágio sin-mineralização. Três dos setores estudados (Chama, Cocorpiña, Huaychulo) estão associados a falhas reversas de direção NNE, enquanto no setor Santo Domingo os veios mineralizados estão condicionados por falhas normais NE, indicando processos tectônicos diversificados para o controle estrutural destes depósitos. Para as mineralizações nos Setores Chama, Cocorpiña e Huaychulo assume-se o período de 40 a 32 Ma, pois estão associadas ao segundo estágio de intrusão do Batólito de Abancay. No setor Mollebamba a mineralização está associada a pórfiro de Cu-Au, (Ponto Trapiche) cuja idade deve corresponder a 29.17 Ma. No setor Santo Domingo os veios auríferos provavelmente são contemporâneos aos veios da jazida Selene datada em 14.62 Ma. O estudo ao longo da área permite identificar, como principais estruturas um Sistema de Dobras NS, que indica uma fase compressiva envolvendo encurtamento aproximadamente E-W, e duas grandes dobras registradas na área... / The study area is located in the Central Andes, south of the Abancay deflection, Peru, is inserted in the (Andahuaylas-Yauri) metallogenic province related to this Abancay batholith, which hosts porphyry-type deposits of skarn Fe-(Cu-Au) and load Au Deposits. It is constituted by clastic and carbonate sequences of Mesozoic age, intruded by granodiorite monzonite plutons and stocks that are overlain by oligomiocenic volcanic rocks related with epithermal gold and silver mineralization in the southeastern part of the region. This paper presents a study of the regional geological setting combined with the analysis of structural pattern in the region between Sabaino and Santo Domingo, with the kinematics characterization of five sectors in the area, where mineralization occurs controlled by fault systems. The analysis includes measures of 119 mesoscopic faults with striations, from which was obtained the stress tensor associated with the sin-mineralization stage. Three of the studied sectors (Chama Cocorpiña, Huaychulo) are associated with reverse faults of NNE, while in Santo Domingo sector the mineralized veins are conditioned by normal faults NE, pointing to diverse tectonic processes for the structural control of these deposits. For mineralization in the sectors Chama, Cocorpiña and Huaychulo is assumed the period 40-32 Ma, as they are associated with the second stage intrusion of Abancay batholith. In Mollebamba sector, the mineralization is associated with porphyry Cu-Au (Trapiche Point) whose age corresponds to 29.17 Ma. In the Santo Domingo sector, the auriferous veins are probably contemporary with the veins of the Selene deposit of age 14.62 Ma. The main large structures identified in the area are a NS fold system, which indicates a compressive phase involving shortening approximately EW, and another system represented by two large folds, the Chapi Chapi Anticline and Huillullu Syncline, which have axial planes parallel to the...

This thesis work was directed at aspects of two related problems: (1) sediment compaction and fluid expulsion processes in a subduction margin accretionary prism, and (2) the nature and concentration of gas hydrates that form bottom-simulating reflectors (BSRs) observed in the accretionary prism sediments of the northern Cascadia margin. The formation of the gas hydrate and the occurrence of BSRs in the study area are believed to be mainly a consequence of upward fluid expulsion in the accretionary prism. Therefore, the two study objectives are closely correlated. Most of this thesis work was carried out analyzing multichannel seismic data and incorporating available information including downhole and other geophysical measurements. Seismic techniques, such as velocity analysis, forward modelling, and waveform velocity inversion, were used in analyzing the data to advance our understanding of the tectonic and geophysical processes in a dynamic accretionary prism environment. The velocity structure and the inferred porosity variations across the frontal region of the accretionary prism have been quantitatively assessed by a detailed seismic velocity analysis. Within the Cascadia basin sediments approaching the deformation front, and within the frontal thrust zone of the accretionary prism, seismic velocities increase landward as a result of sediment consolidation. An important conclusion is that more than one third of the pore fluid content of the incoming sediment is lost by the time they are incorporated into the accretionary prism. In the lower slope region of the deformation front, a pronounced velocity decrease is evident. This low-velocity zone is explained by underconsolidation resulting from rapid horizontal shortening and vertical thickening of the sediment column, accommodated by displacements along thrust faults or by distributed deformation. A prominent BSR becomes visible immediately landward of the deformation front in the accreted sediment, and is developed over much of the low-to-mid continental slope. The upward pore-fluid migration is believed to play an important role in the formation of a gas hydrate BSR. From the estimated fluid loss of 35% over the 3-km-thick Cascadia Basin sediments with an average sediment porosity of 30%, the quantity of the expelled fluid reaches 315 m3/m2 over a distance of 12 km before the basin sediments are incorporated into the accretionary prism. Assuming that 100 mmol/L of methane is removed from the expelled fluid as it moves into the hydrate stability field, a 90-m-thick layer with an average hydrate saturation of 10% of the pore space can be formed by the rising fluids. A velocity-depth function in the lower slope region, representing a no-hydrate/no-gas reference profile, has been established from the detailed semblance velocity analyses and the ODP log data. The observed and measured sediment velocities near the ODP drill sites increase downward more rapidly than the reference profile above the BSR. Based on the reference profile, the velocity inversion results imply that the velocity increase due to hydrate above the BSR accounts for ~2/3 of the impedance contrast required to produce the BSR reflection amplitudes. The remainder of the impedance contrast appears to come from the velocity decrease associated with small concentrations of free gas below the BSR. The integrated analysis of the multichannel seismic and ODP downhole velocity data has allowed the velocity enhancement associated with the formation and concentration of gas hydrate to be estimated. If the BSR is overlain by a 100 m zone of sediment with a mean porosity of 50% in which the hydrate saturation increases linearly from zero at the top of the zone to 20% at the BSR, the estimated hydrate concentration-depth profiles indicate a total hydrate amount of about 5 m3/m2 of ocean floor or methane amount of 820 m3/m2 at STP. Throughout the Vancouver Island continental margin, where the clear BSR have been observed in an area of 30x200 km, the total methane gas estimated can amount to about 175 Tcf (trillion cubic feet) or 2.6 Gt of carbon. / Graduate

Orientador: Luiz Sérgio Amarante Simões / Banca: Carlos Humberto da Silva / Banca: George Luiz Luvizotto / Resumo: A área de estudo se localiza nos Andes Centrais, ao sul da Deflexão de Abancay, Peru, inserida na província metalogenética (Andahuaylas-Yauri) relacionada ao Batólito de Abancay, que hospeda depósitos do tipo pórfiro-skarn de Fe-(Cu-Au) e depósitos filoneanos de Au. É constituída por sequências clásticas e carbonatadas de idades mesozóicas, intrudidas por plutons e stocks de monzonito e granodiorito que, por sua vez, são sobrepostos por rochas vulcânicas oligomiocênicas relacionadas com mineralização auroargentífera na porção sudeste da região. Neste trabalho apresenta-se um estudo do quadro geológico regional aliado à análise do padrão estrutural da região entre Sabaino e Santo Domingo, com a caracterização da cinemática de sistemas de falhas de cinco setores dessa área, onde ocorrem mineralizações, abrangendo medidas de 119 falhas mesoscópicas com estrias, a partir das quais obteve-se os tensores de esforços relacionados com o estágio sin-mineralização. Três dos setores estudados (Chama, Cocorpiña, Huaychulo) estão associados a falhas reversas de direção NNE, enquanto no setor Santo Domingo os veios mineralizados estão condicionados por falhas normais NE, indicando processos tectônicos diversificados para o controle estrutural destes depósitos. Para as mineralizações nos Setores Chama, Cocorpiña e Huaychulo assume-se o período de 40 a 32 Ma, pois estão associadas ao segundo estágio de intrusão do Batólito de Abancay. No setor Mollebamba a mineralização está associada a pórfiro de Cu-Au, (Ponto Trapiche) cuja idade deve corresponder a 29.17 Ma. No setor Santo Domingo os veios auríferos provavelmente são contemporâneos aos veios da jazida Selene datada em 14.62 Ma. O estudo ao longo da área permite identificar, como principais estruturas um Sistema de Dobras NS, que indica uma fase compressiva envolvendo encurtamento aproximadamente E-W, e duas grandes dobras registradas na área... / Abstract: The study area is located in the Central Andes, south of the Abancay deflection, Peru, is inserted in the (Andahuaylas-Yauri) metallogenic province related to this Abancay batholith, which hosts porphyry-type deposits of skarn Fe-(Cu-Au) and load Au Deposits. It is constituted by clastic and carbonate sequences of Mesozoic age, intruded by granodiorite monzonite plutons and stocks that are overlain by oligomiocenic volcanic rocks related with epithermal gold and silver mineralization in the southeastern part of the region. This paper presents a study of the regional geological setting combined with the analysis of structural pattern in the region between Sabaino and Santo Domingo, with the kinematics characterization of five sectors in the area, where mineralization occurs controlled by fault systems. The analysis includes measures of 119 mesoscopic faults with striations, from which was obtained the stress tensor associated with the sin-mineralization stage. Three of the studied sectors (Chama Cocorpiña, Huaychulo) are associated with reverse faults of NNE, while in Santo Domingo sector the mineralized veins are conditioned by normal faults NE, pointing to diverse tectonic processes for the structural control of these deposits. For mineralization in the sectors Chama, Cocorpiña and Huaychulo is assumed the period 40-32 Ma, as they are associated with the second stage intrusion of Abancay batholith. In Mollebamba sector, the mineralization is associated with porphyry Cu-Au (Trapiche Point) whose age corresponds to 29.17 Ma. In the Santo Domingo sector, the auriferous veins are probably contemporary with the veins of the Selene deposit of age 14.62 Ma. The main large structures identified in the area are a NS fold system, which indicates a compressive phase involving shortening approximately EW, and another system represented by two large folds, the Chapi Chapi Anticline and Huillullu Syncline, which have axial planes parallel to the... / Mestre