Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Bibliography: leaves 179-187. Also available online.

Σκοπός της παρούσας εργασίας είναι ο προσδιορισμός των μηχανικών παραμέτρων του βραχώδους υλικού μέσα από εργαστηριακές δοκιμές Βραχομηχανικής ώστε να διεξαχθούν συμπεράσματα για την συμπεριφορά του. Στο τέλος παρουσιάζονται συνολικά τα αποτελέσματα εργαστηριακών δοκιμών και εξάγονται συμπεράσματα για τα πετρώματα διαφόρων περιοχών. / The purpose of this study is to determine the mechanical parameters vrachodous material through laboratory tests conducted to Rock conclusions about the behavior. At the end shown at the results of laboratory tests and conclusions are drawn on rocks of different areas.

Made available in DSpace on 2014-06-11T19:23:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-20Bitstream added on 2014-06-13T18:09:40Z : No. of bitstreams: 1 souza_ae_me_bauru.pdf: 2026557 bytes, checksum: 7c154df4043c97f750918f33c97e250f (MD5) / Foi estudada a influência de cinza de bagaço de cana e rocha sedimentar, adicionadas a um material argiloso, durante o processo de sinterização. O material argiloso e os aditivos foram caracterizados utilizando Difratometria de Raio X, Espectrometria de flurescência de Raio X e Análise Térmica. As amostras de cinza e rocha foram moídas, peneiradas a 0,088 mm e 0,125 mm, respectivamente, e incorporadas nos teores de 0, 20, 40, 60 e 80% em massa ao material argiloso. Foram preparados corpos de prova, prensados uniaxialmente a 19 Mpa, para cada corpo de prova, em uma prensa manual. As peças foram sinterizadas nas temperaturas de 500, 800, 900, 1000, 1100 e 1200º C, usando um forno tipo mufla e, posteriormente, submetidos a análise difratométrica e a ensaios físicos e mecânicos de absorção de água, retração linear de queima, massa específica aparente, perda de massa ao fogo, porosidade aparente e módulo de ruptura à flexão. A difratometria de raios X mostrou que a cinza é composta de material cristalino, predominantemente quartzo; a rocha sedimentar apresentou, além de quartzo, argilominerais micáceos e o material argiloso teve como fase principal a caulinita, contendo ainda hidróxido de alumínio e óxidos de ferro em menores concentrações. A análise química mostrou que, além do silício, a cinza e a rocha sedimentar apresentaram concentrações de óxidos de alumínio, potássio, cálcio, ferro e magnésio, enquanto que no material, os óxidos de silício, alumínio, ferro e titânio foram predominantes. As análises térmicas das diferentes misturas mostraram algumas reações que indicam transformação (inversão do quartzo), decomposição (perda de hidróxidos) e formação de fase (mulita) durante o aquecimento das amostras. Difração de raios X sustentou as hipóteses levantadas nos termograms das amostras... / The influence of sugar cane bagasse ash and sedimentary rock, added to clay material, in the sintering process was studied. The clay material and the additives were characterized by X-ray diffraction, X-ray spectroscopy and thermal analysis. The ash and rock samples were triturated, sieved to 0.088 mm and 0.125 mm, respectively, and incorporated at 0, 20, 40, 60, and 80% in the clay material. Prismatic probes were prepared, each pressed at 19 Mpa in a manual press. The pieces were sintered at 500, 800, 900, 1000, 1100 ans 1200ºC, and then characterized by X-ray diffraction and tests for water absorption, linear shrinkage, apparent specific mass, loss on ignition, apparent porosity and flexural strength. X-ray diffraction showed that the ash was composed of crystalline material, predominantly quartz; the sedimentary rock contained, besides quartz, mica; and the main phase of the clay material was kaolinite, but also contained aluminum hydroxide and iron oxides in lower concentrations. Chemical analysis showed that, besides silicon, the ash and the sedimentary rock also contained concentrations of oxides of aluminum, potassium, calcium, iron and magnesium, while in the clay material, silicon oxide, aluminum, iron and titanium were predominant. Thermal analyses of the different of the mixtures showed some reactions that indicated transformation (inversion of the quartz), decomposition (loss of hydroxides) and phase formation (mullite) during the heating of the samples. X-ray diffraction supported the findings in the thermal analysis of the analyzed samples. The tests showed that both the ash and sedimentary rock worsened the mechanical properties of the clay material, although they contributed to the improvement of other attributes. The presence of quartz in the ash and rock hindered the formation of the mullite phase formed during the sintering process... (Complete abstract click electronic acess below)

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Orientador: Mario Luis Assine / Banca: Rosemarie Rohn Davies / Banca: Almério Barros França / Resumo: A Formação Rio Bonito é a unidade inferior do Grupo Guatá, Eopermiana da Bacia do Paraná. Compreende, da base para o topo, os membros Triunfo, Paraguaçu e Siderópolis. No Estado do Paraná, a espessura da Formação Rio Bonito diminui para norte, principalmente em conseqüência do adelgaçamento e acunhamento do Membro Triunfo, que desaparece no sul do Estado de São Paulo. Para investigar estas variações de espessura e de fácies na Formação Rio Bonito, foi escolhida uma área no nordeste do Estado do Paraná onde a unidade apresenta bons afloramentos e poços para correlação, além de existirem importantes ocorrências de carvão. Para atingir os objetivos propostos, foram levantados perfis estratigráficos verticais e confeccionadas seções estratigráficas, levantados dados de paleocorrentes, caracterizadas associações de fácies sedimentares, correlacionados dados de superfície com os de perfis de poços, interpretados os paleoambientes de sedimentação e comparado o empilhamento estratigráfico da área estudada com o de áreas adjacentes. Cinco associações de fácies foram caracterizadas, permitindo constatar que a parte inferior da Formação Rio Bonito no nordeste do Estado do Paraná apresenta espessuras variáveis por ser o produto de preenchimento sedimentar uma sobre superfície deposicional irregular. Devido à existência de paleovales na superfície do topo do Grupo Itararé, de estruturas sedimentares produzidas por correntes de maré e de paleocorrentes bipolares para norte e sul, a parte inferior da Formação Rio Bonito foi interpretada como produto de preenchimento de vales incisos por depósitos aluviais e de canais de maré (associações de fácies 1 e 2, Membro Triunfo), sobrepostos retrogradacionalmente por lamitos e arenitos de canais de maré da zona central do estuário (associação de fácies 3)...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Rio Bonito Formation is the lowermost unit of the Guatá Group, Early Permian of the Paraná Basin. It comprises from the bottom to the top, the Triunfo, Paraguaçu and Siderópolis Members. In the State of Paraná, the thickness of the Rio Bonito Formation decreases northwards, mainly because of the thinning and wedging out of the Triunfo Member, which disappears in the south of the State of São Paulo. To investigate thickness and facies variations in the Rio Bonito Formation, an area in the northeast of the State of Paraná was chosen wherein the unit presents good outcrops and wells for correlation, besides the existence of important coal beds. To reach the proposed objectives, vertical stratigraphic profiles and stratigraphic sections were made, paleocurrents data were obtainded, sedimentary facies were characterized, correlation between surface and well profile data were performed, sedimentation paleoenvironments were interpreted and the local stratigraphic succession correlated with adjacent areas. Five facies associations were characterized, being possible to observe that the thickness variations of the Rio Bonito Formation in the northeast of the State of Paraná resulted from sedimentation on an irregular depositional surface. Due to the existence of paleovalleys and the sedimentary structures produced by tide currents and bipolar paleocurrents towards the north and south, the lower portion of the Rio Bonito Formation was interpreted as a product of incised-valleys filled-up by estuarine alluvial and tidal channels deposits (facies associations 1 and 2, Triunfo Member). The succession is retrogradational and the basal section is overlayed by mudstones and sandstones of tidal-channels from the innermost portion of the estuary (facies association 3)...(Complete abstract click electronic access below) / Mestre

Orientadores: Frésia Soledad Ricardi Torres Branco, Ismar de Souza Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-18T21:34:34Z (GMT). No. of bitstreams: 1 Tavares_SandraAparecidaSimionato_M.pdf: 8529535 bytes, checksum: 81caa7b6648edbc9a42d10c5ee967375 (MD5) Previous issue date: 2011 / Resumo: O Afloramento Santa Irene tem sido considerado um dos mais significativos da Bacia Bauru, na Formação Adamantina, pela abundancia e boa conservação de fósseis associados ali encontrados, como dentes isolados de arcossauros carnívoros associados a fósseis de um dinossauro saurópode herbívoro. Os fósseis foram coletados nos anos de 1997 e 1998, na área rural do Município de Monte Alto - SP, e hoje compõem parte do acervo do Museu de Paleontologia de Monte Alto. Os dentes isolados de tal afloramento são o principal material de estudo deste trabalho, que, acrescidos a outros dados obtidos através da análise das feições bioestratinômicas e geológicas da região, permitiram tecer uma interpretação paleoecológica para o Afloramento Santa Irene. Foram analisados vinte e seis exemplares de dentes de arcossauros carnívoros, sendo dezoito deles enquadrados como Theropoda e oito como elementos dentários pertencentes aos Crocodyliformes. Os dentes de Theropoda se distinguem daqueles de Crocodyliformes por serem os primeiros mais achatados lateralmente, além de apresentarem serrilhas. Foi possível constatar que quatorze dos dezoito exemplares classificados dentro da Subordem Theropoda apresentam características pertencentes à Ceratosauria, família Abelisauridae, e Maniraptora, família Dromaeosauridae. A coleção de dentes de Crocodyliformes coletados no afloramento Santa Irene consiste de oito exemplares em geral cônicos, com estriamento ao longo da carena, podendo ou não apresentar bordos serrilhados e seção basal arredondada, sendo possível classificá-los dentro da família Trematochampsidae. Os fósseis articulados e com pouco desgaste do Aeolosaurus indicam um soterramento parcial logo após a morte ou ainda na fase de destruição de seus elementos não esqueléticos. A observação do afloramento e do seu entorno permitiu deduzir que a região apresentava rios, possivelmente, entrelaçados com deposição sazonal de sedimentos e períodos de estabilidade com a formação de solos incipientes. Durante os períodos interdeposicionais e de formação do solo, nota-se a ocorrência da precipitação de minerais, dando origem à formação de calcretes, resultado de períodos secos marcantes. O afloramento Santa Irene representa a deposição de rios que formavam barras arenosas, nas quais diversos grupos de animais buscavam água e alimento. Conclui-se que estes animais habitavam ou transitavam por aquele ambiente, pois não há sinais de que os fósseis tenham sido transportados até o local no qual foram coletados, mas sim que a carcaça do Aeolosaurus serviu de alimentação para outros animais no local de sua morte. Desta forma, o material analisado permitiu a reconstituição de um retrato impar de um ecossistema a muito extinto / Abstract: The Santa Irene outcrop has been considered one of the most significant of the Bauru Basin, in the Adamantina formation, because of abundance and good preservation of associated fossils found there, as isolated teeth of carnivorous archosaurs associated with fossils of a herbivorous sauropod dinosaur. The fossils were found in 1997 and 1998, in rural areas of the city of Monte Alto - SP, and today compose the collection of the Museum of Paleontology of Monte Alto. The isolated teeth from this outcrop is the main material of this paper, which, together with other data obtained by analysis of biostratonomic and geological features of the region, allowed to make a paleoecological interpretation of the outcrop Santa Irene. Twenty-six copies of teeth of carnivorous archosaurs were analyzed, eighteen of them being classified as Theropodomorpho and eight teeth as belonging to Crocodyliformes. The teeth of Theropodomorpho can be distinguished from those to be the first Crocodyliformes as they are more flattened laterally, besides having serrations. It was found that fourteen of the eighteen specimens classified within the suborder Theropoda fit the characteristics belonging to Ceratosauria, family Abelisauridae and Maniraptora, family Dromaeosauridae. The collection of Crocodyliformes teeth collected from the outcrop Santa Irene consists of eight copies generally conical, with streaking along the keel, presenting or not serrated edges and rounded basal section, being possible to classify them within the family Trematochampsidae. The articulated and with little wear fossils of Aeolosaurus indicate a burial soon after death or during the destruction of its non-skeletal elements. The observation of the outcrop and its surroundings allow deducing that the region had braided rivers with seasonal sediment deposition and periods of stability with the formation of incipient soils. During no deposicional intervals periods and soil formation, can be noted the occurrence of precipitation of minerals, giving rise to the formation of calcrete, result of striking dry periods. The outcrop of St. Irene was formed by rivers that formed sand bars, in which various groups of animals tried to find food and water. It can be deduced that these animals lived or transited through that environment, because there is no evidence that the fossils were transported to the location in which they were collected, but that the Aeolosaurus remains served as food for other animals at his death location. Thus, the analyzed material allowed the reconstitution of an unique portrait of an ecosystem to long extinct / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

No description available.

The Seychelles Microcontinent (SMc) is a fragment of continental lithosphere that experienced multiple phases of rifting and thermal subsidence during its isolation and submergence within the Indian Ocean. Originally part of central Gondwana, along with India and Madagascar, the SMc first emerged during Mesozoic fragmentation of Gondwana (ca. 220 – 180 Ma) along a complex rifted margin. Fragmentation involved three major rift phases, viz.: 1) Middle Triassic – Middle Jurassic (Rift I), associated with the “Karoo rifts” and break-up between [India-Madagascar-Seychelles] and East Africa; 2) Middle Jurassic – Early Cretaceous (Rift II), associated with the rifting and break-up of Madagascar from [India-Seychelles]; 3) Late Cretaceous (Rift III), associated with the rifting and final break-away of the SMc from India. In this study, the tectonic and sedimentary history of the SMc is analysed using 2D seismic reflection datasets and three exploration wells. Seismic to well-log correlations provide a chrono-stratigraphic framework that identifies seven sequences from the Middle Triassic to the Paleogene. This also identified horst and graben structures related to the extensional tectonics and thermal subsidence of this continental fragment. The latter is reflected also in changes of its litho-facies preserved on the SMc, from terrestrial to marine. The oldest sedimentary rocks identified on the SMc are Middle Triassic organic rich claystones (Sequence 7, Rift I), which grade upwards into alternating Upper Triassic sandstones and mudstones (Sequence 6, Rift I) followed by upward coarsening Lower Jurassic mudstones to sandstone units (Sequence 5, Rift I). These sequences are interpreted as lacustrine facies that evolved into fluvial channel migration facies and finally into progradational delta front facies. Sequence 5 is overlain by Middle Jurassic oolitic limestones that grade upwards into organic rich mudstones (Sequence 4, thermal subsidence after Rift I); the latter are interpreted as restricted-marginal marine deposits. Following Sequence 4, separated by a major break-up unconformity (BU), are the Upper Cretaceous open marine deposits comprising limestones, claystones and sandstones, and terminated with basaltic volcanics (ca. 66 Ma) prior to the separation of the SMc from India (Sequence 3, Rift III). This is overlain by the post-rift – thermal subsidence sequences comprising open marine claystones and shelf limestones (Sequence 2) followed by a sequence of shelf limestones (Sequence 1) that form the present carbonate platform, the Seychelles Plateau that lies approximately 200 m below the present sea-level. Backstripping and subsidence analysis quantifies 3 stages of subsidence; Phase A: Slow subsidence (ca. 5-20 m/Ma), from the Middle Jurassic to the Upper Cretaceous that terminated during a major marine transgression during ingression of the Tethys Sea between East Africa and [Madagascar-Seychelles-India]. This created marine conditions and the subsequent deposition of Sequences 4 and 3; Phase B: Accelerated subsidence (ca. 35-60 m/Ma) recorded throughout the Paleocene to the middle Eocene leading to deeper marine conditions and the subsequent deposition of Sequence 2; and Phase C: Reduced subsidence (ca. 10-30 m/Ma) following the interaction between the Carlsberg Ridge and the Reunion hotspot (ca. 55 Ma) that possibly introduced a reduction in subsidence and the subsequent deposition of Sequence 1 as the SMc drifted and thermally subsided to its submerged present location, and is now dominated mainly by marine carbonates. The effects of the Madagascar and Seychelles/India separation (ca. 84 Ma) are not observed in the subsidence analysis, possibly because it involved transcurrent-rotational movement between the two plates over a short period of time.

Lake sediment cores collected from four lakes (Upper Fly Lake 61.04°N, 138.09°W, 1326 m a.s.l.; Jenny Lake 61.04°N, 138.36°W, 817 m. a.s.l.; Donjek Kettle 61.69°N, 139.76°W, 732 m a.s.l.; Lake WP02 61.48°N, 139.97°W, 1463 m a.s.l.) in the southwest Yukon provide records of postglacial climatic variability in the region. A 13,000 year pollen record from Upper Fly Lake indicated that herbaceous tundra existed on the landscape from 13.6 to 11 ka, followed by birch shrub tundra until 10 ka, when Picea forests were established in the region. Pollen-, chironomid-, and ostracode-inferred paleoclimate reconstructions showed a long-term cooling with increasing moisture from the late glacial through the Holocene. The early and mid-Holocene were warm and dry, with cool, wet conditions after 4 ka, and warm, dry conditions over the last 100 years. Chironomid accumulation rates provided evidence of millennial-scale climate variability, and the chironomid community responded to rapid climate changes. Late Holocene environmental variability was investigated through the analysis of paleoproduction indices (sediment loss-on-ignition, biogenic silica) and chironomid and ostracode communities. Coherent trends were revealed among the four lakes and pairs of sites located closer together showed more similarities than more distant sites located in similar environments (alpine tundra or boreal forest). Chironomid-inferred paleotemperature estimates are inconsistent with other data from the region, however certain fluctuations in paleoproduction indices and changes in abundance and composition of the chironomid and ostracode communities compare well with interpretations based on independent paleoclimate records. The White River Ash event (1147 cal yrs BP and 1953 cal yrs BP) impacted three of the four aquatic ecosystems studied, with a greater impact occurring at sites with greater ash thickness. Interannual variability in the lake environment is of lesser concern when deriving inference models relating organisms to environmental variables, and the results presented here provide guarded optimism that the sampling methodology applied in paleolimnological studies is appropriate in this region.

This study is part of a project aiming for the long-term burying of nuclear wastes in Kincardine, Ontario. Bedrock formations as well as their associated waters were analyzed in drill cores from the Michigan sedimentary basin, southwest Ontario. This research utilizes geochemistry combined to strontium and rubidium isotope ratios in order to determine the origin of porewaters from Ordovician shales and limestones. It is demonstrated that these waters are the result of a mixing line between the Silurian (Guelph) and Cambrian groundwaters. This last end-member was also mixed with Precambrian brines to some extent. Strontium and rubidium isotopes also demonstrated rubidium in clays were leached by porewaters over time. Once in solution, radioactive rubidium decayed into strontium over time. This process explains the accumulation of radiogenic strontium observed in porewaters. An age estimate for the deposition of carbonates and other evaporates was calculated with the Rb-Sr isotope system. The calculated age is 453.7 million years before present for dolomites, which is consistent with the history of the site. It was possible to gen an approximate age of 339.7 million years for the formation of illites. This corresponds to the illitization process that occurred after the deposition of rocks, when the Silurian brines infiltrated the deeper Ordovician shale. It was also possible to estimate of porewaters ages.