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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Caractéristiques, chronologie et typologie des minéralisations aurifères de la région du Lac Shortt (Québec), sous-province archéenne de l'Abitibi /

Brisson, Harold, January 1998 (has links)
Thèse (D.R.M.)--Université du Québec à Chicoutimi, 1998. / Document électronique également accessible en format PDF. CaQCU
132

Geochemistry of the sediment-hosted disseminated gold deposits in Southwestern Guizhou Province, China /

Bao, Zhiwei, January 2001 (has links)
Thèse (D.Ress.Min.)--Université du Québec à Chicoutimi. / Bibliogr.: pp. 220-242. Document électronique également accessible en format PDF. CaQCU
133

Geology, geochemistry, geochronology and genesis of granitoid clasts in breccia-conglomerates, MacLean extension orebody, Buchans, Newfoundland /

Stewart, Peter William, January 1985 (has links)
Thesis (M.Sc.) -- Memorial University of Newfoundland. / Typescript. Bibliography : leaves 266-289. Also available online.
134

The tectono-metallogenesis during the irumide and pan-African events in South West Africa/Namibia

Tregoning, Trevor Denzil 05 March 2013 (has links)
A large portion of South west Africa/Namibia is underlain by 2 great orogens. They are the Irumide (Sinclair/Rehoboth) and Damara Orogenies. The L-shaped Irumide Province forms part of a belt which extends over the subcontinent from Namaqualand to as far as Zambia. The volcano-sedimentary sequences of the Irumide are believed to have formed in intracratonic rifts and pull-apart basins during the period 1400 to 900 Ma. The evolution of the NW trending Sinclair Group proceeded by means of 3 major cycles each beginning with the emplacement of basic to intermediate magmas followed by felsic ones. The cycle ended off with subsidence, deposition of immature clastic debris and final tilting of the volcano-clastic sequence. It was suggested that the extensive calc-alkaline lavas present, developed within a magmatic arc above a subduction zone, but this proposal has not been generally accepted. The NE trending Klein Aub-Witvlei Basins consist essentially of red bed alluvial fans and lacustrine sediments with minor volcanics near the base. The red beds and aeolian sediments were deposited in an arid climatic condition. The regional greenschist facies metamorphism and deformation is attributed to a major tectono-thermal event at 1100 Ma. The Damara Orogen (900 - 550 Ma) forms part of the Pan-African mobile belt system of global proportions. The NE trending intracontinental branch (aulacogen) and 2 coastal branches constitute a triple junction with its focal point near Swakopmund. The NE extension of the intracontinental belt has been linked with the Lufilian Arc hosting the renown Zambian Copper Belt deposits. In South West Africa/Namibia this belt hosts many different mineral occurrences which can be grouped into rift and collision related deposits. The tectonic history of the Damara Orogen supports a geodynamic-evolution-with-time hypothesis and represents a transitional phase in which limited Wilson Cycle Tectonics was active. The Theory of Mantle Advection is invoked to explain rifting, thinning and subsidence. Extensive ensialic rifting resulted in a relatively stable Northern Carbonate Platform and several deep troughs hosting turbiditic sequences. Crustal rupture in the Khomas Trough allowed for the emplacement of ocean floor tholeiites known as the Matchless Amphibolite Belt. Subsequent ocean closure and collision resulted in deformation, metamorphism and generation of predominantly S-type granites. The southern continental plate was partially overridden by the northern plate during final collision at 550 Ma. These low angle thrust faults allowed for the emplacement of the Naukluft Nappe Complex on top of younger Nama sediments. The break up of Gondwanaland during the Mesozoic with the splitting of the Atlantic Ocean was responsible for the intrusion of anorogenic alkaline ring complexes along the extension of the NE trending transform faults within the intracontinental branch of the Damara Orogen. A close relationship between the tectonic setting and mineral deposits has been recognized in both the Irumide and Damara Orogenies. In the Irumide, stratiform syngenetic copper deposits are hosted by alluvial fan, playa and lacustrine sediments. The uninterrupted sedimentation from the Irumide to Damara Orogen resulted in similar stratiform copper deposits during the early stages of rifting. In the Damara Orogen the rifting (extensional) phase is characterized by 4 main mineralizing systems: diagenetic/syngenetic (Kupferschiefer-type), epigenetic/hydrothermal Cu-Pb-Zn (Mississippi Valley-type), volcanogenic cupriferous pyrite (Besshi-type) and volcano-exhalative Pb-Zn (Red Sea-type). The collision (compressional) phase was accompanied by 4 main mineralizing processes: epigenetic/hydrothermal Cu-Pb-Zn, hydrotheral/metasomatic Sn-W-rare earth, metamorphogenic Au and U-bearing anatectic melts. The key to the selection of viable exploration targets lies in the understanding of the field evidence and the geodynamics modelling to explain the evolution of the orogen and its associated mineral deposits.
135

Tectônica e proveniência do grupo Santa Bárbara, região de Minas do Camaquã - RS

Bicca, Marcos Muller January 2013 (has links)
A região de estudo localiza-se na porção da Bacia do Camaquã, sendo classicamente conhecida com “Janela Bom Jardim”. Esta área já foi intensamente estudada, principalmente em decorrência dos depósitos minerais amplamente distribuídos. Apesar disso ainda não existe um consenso com relação à evolução tectônica da região, desde processos formadores da bacia até eventos pósdeposicionais, como também com relação ao seu posicionamento estratigráfico dentro da sequência deposicional da Bacia do Camaquã. Dessa forma, este trabalho vem contribuir e acrescentar aos modelos anteriores com dados geocronológicos e termocronológicos, aplicados diretamente às rochas sedimentares da região, bem como, novos dados de estrutural. Para tanto, submetemos seis amostras de rochas sedimentares da região de Minas do Camaquã à análise pelo método U-Pb com LA-ICP-MS e SHRIMP, aplicado a zircões detríticos, no intuito de mapear possíveis áreas fonte dos sedimentos como também, propor uma idade máxima de deposição para a sequência. Estas mesmas amostras foram utilizadas para separação de apatitas para análise termocronológicas (traços de fissão em apatitas), com o objetivo de caracterizar eventos de soerguimento e denudação relacionados à tectônica que afetou a área. O estudo de proveniência possibilitou identificar uma grande contribuição de zircões de idade Brasiliana, principalmente do final do Neoproterozóico e secundariamente populações de zircões de idade Paleoproterozóica, principalmente relacionadas ao Ciclo Transamazônico. A população principal foi correlacionada às intrusões graníticas do Terreno Taquarembó, e possivelmente contribuições do Batólito Pelotas, como também, das sequências vulcano-sedimentares mais antigas da própria Bacia do Camaquã. As idades Paleoproterozóicas foram atribuídas á rochas do Complexo Granulítico Santa Maria Chico e Complexo Encantadas, como também, zircões retrabalhados das rochas metassedimentares do Complexo Metamórfico Porongos. Ainda foi possível estimarmos a idade máxima de deposição da sequência em 554 Ma a partir do grão de zircão mais jovem datado posicionando estas rochas dentro do intervalo deposicional do Grupo Santa Bárbara. A análise por traços de fissão em apatitas permitiu identificar quatro populações de idades principais. Estas populações foram atribuídas à influência de dois eventos orogênicos na margem sul – ocidental do Gondwana: Famatiniana e Gondwanides. O primeiro evento é bem documentado pelas populações de 407-362 Ma e o segundo pelas populações de 302 Ma e 242-211 Ma. A quarta população (133 Ma) foi registrada em uma única amostra indicando um evento térmico ocasionado por intrusões vulcânicas associadas ao vulcanismo Paraná-Etendeka (Cretáceo inferior). Por fim, dados estruturais permitiram identificar uma evolução tectônica complexa, marcada por processos relacionados formação da bacia até reativações pósdeposicionais. Os eventos D1 e D2 foram associados a esforços gerados durante os estágios finais do Ciclo Brasiliano, com campos de tensão S10E-N10W e SE-NW, respectivamente. Um evento D3 com campo de tensão W-L registra reativações causadas pela Orogenia Famatiniana. O evento D4 marcado por uma compressão NNE-SSW e uma extensão NE-SW são relacionados aos processos tectônicos Triássicos (Orogenia Gondwanides). Um último evento D5 extensional (L-W) foi correlacionado aos processos de separação do Gondwana. / The study area is located in the southern portion of the Camaquã Basin, being classically known as "Bom Jardim Window". This area has been intensely studied, mainly due to the ore deposits widely distributed. Yet there is still no consensus regarding the tectonic evolution of the region, since basin inception processes until postdepositional events, but also regarding its stratigraphic position within the depositional sequence Basin Camaquã. Thus, this work contributes to previous models with geochronological and thermochronological data, applied directly to the sedimentary rocks of the region, as well as new structural data. Therefore, we submitted six samples of sedimentary rocks from the Camaquã Mines region to U-Pb method with LA-ICP-MS e SHRIMP applied to detrital zircons in order to map possible source areas of the sediments, as well as, proposing a maximum depositional age for the sequence. These same samples were used for apatite separation for thermochronological analysis (apatite fission tracks), with the aim of characterizing uplift and denudation events related to tectonics process that affected the area. Provenance study enabled us to identify a large contribution of Brasiliano zircon ages, especially from Late-Neoproterozoic and secondarily, zircons populations of Paleoproterozoic age, mainly related to Trans-Amazonian Cycle. The main population was correlated with granitic intrusions from Taquarembó Terrene and possibly contributions from Pelotas Batholith, as well as, from older volcano-sedimentary sequences of the Camaquã Basin. Paleoproterozoic ages were assigned to rocks of Santa Maria Chico Granulitic Complex and Encantadas Complex, as well as, reworked zircons from metasedimentary rocks of Porongos Metamorphic Complex. Still it was possible to estimate the maximum deposition age of the sequence on 554 Ma from the youngest zircon grain dated. Previous isotopic data allow positioning these rocks within the depositional range of Santa Bárbara Group. Apatite fission track analysis identified four main ages populations. These populations were attributed to the influence of two orogenic events on the Southwestern margin of Gondwana: Famatinian and Gondwanides. The first event is well documented by the 407-362 Ma age populations and the second by the 302 Ma and 242-211 Ma. The fourth population (133 Ma) was recorded in only one sample indicating a thermal event caused by volcanic intrusions associated with volcanism Paraná-Etendeka (Lower Cretaceous). Finally, structural data allowed identifying a complex tectonic evolution, characterized by basin inception processes until post-depositional reactivations. The events D1 and D2 were associated with stresses generated during the final stages of the Brazilian Cycle with stress fields of S10E-SE-NW and SE-NW, respectively. A third event (D3) with W-L stress field records the reactivation Famatinian Orogeny. The D4 event marked by a NNE-SSW compression and a NE-SW extension related to Triassic tectonic processes (Gondwanides Orogeny). One last extensional (W-L) event (D5) was correlated to the processes of separation of Gondwana.
136

Tectônica e proveniência do grupo Santa Bárbara, região de Minas do Camaquã - RS

Bicca, Marcos Muller January 2013 (has links)
A região de estudo localiza-se na porção da Bacia do Camaquã, sendo classicamente conhecida com “Janela Bom Jardim”. Esta área já foi intensamente estudada, principalmente em decorrência dos depósitos minerais amplamente distribuídos. Apesar disso ainda não existe um consenso com relação à evolução tectônica da região, desde processos formadores da bacia até eventos pósdeposicionais, como também com relação ao seu posicionamento estratigráfico dentro da sequência deposicional da Bacia do Camaquã. Dessa forma, este trabalho vem contribuir e acrescentar aos modelos anteriores com dados geocronológicos e termocronológicos, aplicados diretamente às rochas sedimentares da região, bem como, novos dados de estrutural. Para tanto, submetemos seis amostras de rochas sedimentares da região de Minas do Camaquã à análise pelo método U-Pb com LA-ICP-MS e SHRIMP, aplicado a zircões detríticos, no intuito de mapear possíveis áreas fonte dos sedimentos como também, propor uma idade máxima de deposição para a sequência. Estas mesmas amostras foram utilizadas para separação de apatitas para análise termocronológicas (traços de fissão em apatitas), com o objetivo de caracterizar eventos de soerguimento e denudação relacionados à tectônica que afetou a área. O estudo de proveniência possibilitou identificar uma grande contribuição de zircões de idade Brasiliana, principalmente do final do Neoproterozóico e secundariamente populações de zircões de idade Paleoproterozóica, principalmente relacionadas ao Ciclo Transamazônico. A população principal foi correlacionada às intrusões graníticas do Terreno Taquarembó, e possivelmente contribuições do Batólito Pelotas, como também, das sequências vulcano-sedimentares mais antigas da própria Bacia do Camaquã. As idades Paleoproterozóicas foram atribuídas á rochas do Complexo Granulítico Santa Maria Chico e Complexo Encantadas, como também, zircões retrabalhados das rochas metassedimentares do Complexo Metamórfico Porongos. Ainda foi possível estimarmos a idade máxima de deposição da sequência em 554 Ma a partir do grão de zircão mais jovem datado posicionando estas rochas dentro do intervalo deposicional do Grupo Santa Bárbara. A análise por traços de fissão em apatitas permitiu identificar quatro populações de idades principais. Estas populações foram atribuídas à influência de dois eventos orogênicos na margem sul – ocidental do Gondwana: Famatiniana e Gondwanides. O primeiro evento é bem documentado pelas populações de 407-362 Ma e o segundo pelas populações de 302 Ma e 242-211 Ma. A quarta população (133 Ma) foi registrada em uma única amostra indicando um evento térmico ocasionado por intrusões vulcânicas associadas ao vulcanismo Paraná-Etendeka (Cretáceo inferior). Por fim, dados estruturais permitiram identificar uma evolução tectônica complexa, marcada por processos relacionados formação da bacia até reativações pósdeposicionais. Os eventos D1 e D2 foram associados a esforços gerados durante os estágios finais do Ciclo Brasiliano, com campos de tensão S10E-N10W e SE-NW, respectivamente. Um evento D3 com campo de tensão W-L registra reativações causadas pela Orogenia Famatiniana. O evento D4 marcado por uma compressão NNE-SSW e uma extensão NE-SW são relacionados aos processos tectônicos Triássicos (Orogenia Gondwanides). Um último evento D5 extensional (L-W) foi correlacionado aos processos de separação do Gondwana. / The study area is located in the southern portion of the Camaquã Basin, being classically known as "Bom Jardim Window". This area has been intensely studied, mainly due to the ore deposits widely distributed. Yet there is still no consensus regarding the tectonic evolution of the region, since basin inception processes until postdepositional events, but also regarding its stratigraphic position within the depositional sequence Basin Camaquã. Thus, this work contributes to previous models with geochronological and thermochronological data, applied directly to the sedimentary rocks of the region, as well as new structural data. Therefore, we submitted six samples of sedimentary rocks from the Camaquã Mines region to U-Pb method with LA-ICP-MS e SHRIMP applied to detrital zircons in order to map possible source areas of the sediments, as well as, proposing a maximum depositional age for the sequence. These same samples were used for apatite separation for thermochronological analysis (apatite fission tracks), with the aim of characterizing uplift and denudation events related to tectonics process that affected the area. Provenance study enabled us to identify a large contribution of Brasiliano zircon ages, especially from Late-Neoproterozoic and secondarily, zircons populations of Paleoproterozoic age, mainly related to Trans-Amazonian Cycle. The main population was correlated with granitic intrusions from Taquarembó Terrene and possibly contributions from Pelotas Batholith, as well as, from older volcano-sedimentary sequences of the Camaquã Basin. Paleoproterozoic ages were assigned to rocks of Santa Maria Chico Granulitic Complex and Encantadas Complex, as well as, reworked zircons from metasedimentary rocks of Porongos Metamorphic Complex. Still it was possible to estimate the maximum deposition age of the sequence on 554 Ma from the youngest zircon grain dated. Previous isotopic data allow positioning these rocks within the depositional range of Santa Bárbara Group. Apatite fission track analysis identified four main ages populations. These populations were attributed to the influence of two orogenic events on the Southwestern margin of Gondwana: Famatinian and Gondwanides. The first event is well documented by the 407-362 Ma age populations and the second by the 302 Ma and 242-211 Ma. The fourth population (133 Ma) was recorded in only one sample indicating a thermal event caused by volcanic intrusions associated with volcanism Paraná-Etendeka (Lower Cretaceous). Finally, structural data allowed identifying a complex tectonic evolution, characterized by basin inception processes until post-depositional reactivations. The events D1 and D2 were associated with stresses generated during the final stages of the Brazilian Cycle with stress fields of S10E-SE-NW and SE-NW, respectively. A third event (D3) with W-L stress field records the reactivation Famatinian Orogeny. The D4 event marked by a NNE-SSW compression and a NE-SW extension related to Triassic tectonic processes (Gondwanides Orogeny). One last extensional (W-L) event (D5) was correlated to the processes of separation of Gondwana.
137

The factors affecting the interpretation of geochemical surveys in mineral exploration

Fletcher, B A January 1982 (has links)
[From introduction] Exploration geochemistry is an indirect method of detecting mineral deposits by measuring the abundance and distribution of ore elements and elements closely associated with ore in natural materials at or near the earth's surface. The method relies on the assumption that a mineral deposit is reflected by unusual element abundances or distribution patterns (geochemical halos), and that these indications of mineralization can be detected by geochemical surveys involving the collection and analysis of natural materials. The interpretation of geochemical surveys in mineral exploration involves: 1) The use of geological and statistical inference, based on a knowledge of the normal behaviour and distribution of indicator elements in the exploration area, to recognize apparent geochemical anomalies in field and analytical data and to predict the type of geochemical halo reflected by the anomalies. 11) The use of geological inference, based on a knowledge of the characteristics of geochemical halos and their relationship to mineral deposits, to predict the presence and probable location of an ore body. The interpretation process is, however, complicated by the absence of a simple universal formula that relates the abundance and distribution of elements in natural materials to the presence or absence of a mineral deposit. The interpretation of a geochemical survey must, thus, be based on an empirical approach which avaluates each survey as an individual problem. The objective of this dissertation is to illustrate the factors affecting the "nuts and bolts" approach to the interpretation of geochemical surveys in mineral exploration. The discussion is aimed at providing field geologists responsible -for the planning and execution of geochemical surveys with some basic guidelines for interpreting the surveys. I hope that the contents of this dissertation will help field geologists to "look in the last place first".
138

The geology and ore deposits of the Mountain Queen area, northern Swisshelm Mountains, Arizona

Loring, William Bacheller, 1915-, Loring, William Bacheller, 1915- January 1947 (has links)
No description available.
139

Structural geologic controls at the San Luis Mines, Tayoltita, Durango, Mexico

Ballard, Stanton Neal, Ballard, Stanton Neal January 1980 (has links)
No description available.
140

Geology and ore deposits of the eastern portion of Hilltop Mine area, Cochise County, Arizona

Papke, Keith G., Papke, Keith G. January 1952 (has links)
No description available.

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