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Paleobiogeographic Analyses of Late Ordovician Faunal Migrations: Assessing Regional and Continental Pathways and MechanismsLam, Adriane R. 25 August 2015 (has links)
No description available.
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Reconstructing the Great Ordovician Biodiversification Event through brachiopods of OklahomaTrubovitz, Sarah, 23 September 2016 (has links)
No description available.
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Analyzing Niche Stability in Late Ordovician Articulated Brachiopod Species during the Richmondian InvasionMalizia, Richard Walter 26 July 2011 (has links)
No description available.
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ROTEIRO GEOLÓGICO NOS MUNICÍPIOS DE CASTRO E TIBAGI, PR – BRASIL.Matsumura, Willian Mikio Kurita 19 April 2010 (has links)
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Previous issue date: 2010-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Campos Gerais region, Paraná, Brazil, holds unique geological, geomorphological e paleontological sets, which are target of numerous works and scientific researcher. This research present a geological and paleontological route using the outcrops occurring along existing roads in the municipalities of Castro and Tibagi, Parana State, Brazil. This roadmap is proposed as a tool to aid teaching and scientific support for fieldworks (classes or applied basic research) developed by teachers and researchers. Fieldwork carried out aimed to the regional recognition and description of stratigraphic
sections of the surface, according to the geological context of the Castro and Paraná basins. For each outcrop were built columnar sections showing the following items: 1) lithological description, 2) sedimentary structures and 3) fossil content occurring. All
outcrops were correlated with stratigraphic frameworks pre-existing. A total of 20 raised and described outcrops then organized in the form of stopping points along the road PR- 151, PR-340, BR-153 and secondary roads. Stratigraphically the roadmap begins in the volcanic and volcaniclastic rocks Ordovician of Castro Basin. Then cover the glacial rocks of Neo-Ordovician from Iapó Formation and the fluvial-marine rocks Siluro-
Devonian from Formation Furnas, and pelitic rocks of the Devonian from Ponta Grossa Formation, ending with the glaciogenic rocks Neo-Carboniferous from Itararé Group
(belonging to the Paraná Basin). This roadmap allows the monitoring of succession lithological, stratigraphic, sedimentological and paleobiological in the interval Lower
Ordovician and Upper Carboniferous in the Campos Gerais region of Paraná, facilitating public access to new target areas of outcrops and providing a history of
research and discoveries each point.. / A região fisiográfica dos Campos Gerais do Paraná é detentora de um conjunto singular de feições geológicas, geomorfológicas e paleontológicas que são alvos de inúmeros trabalhos e pesquisas científicas. Apresenta-se aqui um roteiro geológico e paleontológico utilizando-se de afloramentos rochosos ocorrentes ao longo de rodovias existentes nos municípios de Castro e Tibagi, Estado do Paraná, Brasil. Este roteiro é proposto como um instrumento de auxílio didático e apoio científico para atividades práticas de campo (aulas ou pesquisa básica aplicada) desenvolvidas por professores e
pesquisadores. Trabalhos de campo realizados objetivaram o reconhecimento regional e a descrição das seções estratigráficas de superfície, segundo o contexto geológico das bacias de Castro e do Paraná. Para cada afloramento foram construídas seções colunares
apresentando os seguintes ítens: 1) descrição litológica, 2) estruturas sedimentares e 3) conteúdo fossilífero ocorrente. Todos os afloramentos foram correlacionados a
arcabouços estratigráficos pré-existentes. No total foram levantados e descritos 20 afloramentos rochosos organizados então sob a forma de pontos de parada ao longo das rodovias PR-151, PR-340, BR-153 e estradas secundárias. Estratigraficamente inicia-se nas rochas vulcânicas e vulcanoclásticas ordovicianas da Bacia de Castro. Em seguida abrange as rochas glaciais neo-ordovicianas da Formação Iapó e as rochas flúviomarinhas siluro-devonianas da Formação Furnas e pelíticas devonianas da Formação Ponta Grossa, encerrando com as rochas glaciogênicas neo-carboníderas do Grupo Itararé (pertencentes à Bacia do Paraná). O presente roteiro permite o acompanhamento
das sucessões litológicas, estratigráficas, sedimentológicas e paleobiológicas no intervalo Ordoviciano Inferior e o Carbonífero Superior na região dos Campos Gerais do Paraná, facilitando o acesso do público alvo a novas regiões de afloramentos e
fornecendo um histórico das pesquisas e descobertas de cada ponto.
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Ordovician (Billingen and Volkhov stages) Brachiopod Faunas of the East BalticEgerquist, Eva January 2004 (has links)
<p>Lower-Middle Ordovician (Arenig) successions in the East Baltic have been investigated for more than one hundred and fifty years. Nevertheless detailed sampling still yields new species and better knowledge of the environment in which these organisms lived. The successions are well suited for bed by bed sampling because of the lack of tectonic disturbance and because the sequences are well documented. </p><p>This study analyses collections of Billingen-Volkhov age mainly from the St. Petersburg region, but also from Estonia. A great deal of the material was obtained from the marly to clayey, soft sediment that intercalates the compact packstones and wackestones in the succession. Twenty-nine of these clay horizons were used for diversity estimates on the fauna through the succession. The most thoroughly investigated groups for this investigation were rhynchonelliformean brachiopods, conodonts and ostracodes. The results indicate that variances in diversity and abundance levels for these groups were not correlated, either to each other or to the small-scale sea level fluctuations that have been suggested for the region. However, diversity dynamics of brachiopods and ostracodes confirm the large-scale upward shallowing of the basin into the Upper Volkhov. Comparison with fossils from the limestones did not reveal any differences in faunal composition between the two preservation modes. </p><p>The detailed sampling, coupled with sampling of the recently described mud mounds that occur in several outcrops, yielded large numbers of specimens. This enabled revision of earlier poorly known rhynchonelliformean genera such as <i>Ujukella</i> Andreev, as well as better known genera such as <i>Porambonites</i> Pander. In total the examined faunas include 31 genera assigned to 53 species of rhynchonelliformean brachiopods. Of these <i>Leoniorthis </i>and <i>Eoporambonites</i> are defined as new genera, and the following new species are described: <i>Neumania paucicostata, Ranorthis rotunda, Orthidium gambolovensis, Orthidium lavensis, Skenidioides minutus, Tetralobula peregrina, Idiostrophia prima</i> and <i>Idiostrophia tenuicostata</i>.</p>
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Characterization of Bacterial Community Structure in Deep Subsurface Sedimentary Core Samples from Michigan Basin, OntarioIlin, Dimitri 10 January 2012 (has links)
Deep subsurface rock samples from Upper Ordovician strata in the Michigan Basin were analyzed for the presence of microbial communities. High concentrations of biogenic methane were observed in the Upper and Middle Ordovician formations. Total porosity values for the shale, shale hard bed and limestone samples were 7.4%, 2.5% and 1.9%, respectively. Hydrocarbon presence ranged from petroliferous shale, to bituminous layering in shale hard beds, to hydrocarbon odour in limestone. Organic carbon content ranged from 0.5 to 2.5%, highest amount being present in the shale. Environmental DNA was extracted from core samples and PCR amplified using 16S rDNA bacterial primers. PCR performed with archaeal 16S rDNA and methanogen-specific (mcrA) primers did not yield DNA amplification. Gene analysis indicated that bacterial sequences similar to Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were present. Most sequences were not related to known cultivated species. Proteobacteria was the most dominant phyla at all depths and included heterotrophic, lithotrophic, acidophilic, radiotolerant, and sulphate-reducing species of bacteria. This study concludes that the observed biogenic methane is a product of ancient methanogenesis.
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Characterization of Bacterial Community Structure in Deep Subsurface Sedimentary Core Samples from Michigan Basin, OntarioIlin, Dimitri 10 January 2012 (has links)
Deep subsurface rock samples from Upper Ordovician strata in the Michigan Basin were analyzed for the presence of microbial communities. High concentrations of biogenic methane were observed in the Upper and Middle Ordovician formations. Total porosity values for the shale, shale hard bed and limestone samples were 7.4%, 2.5% and 1.9%, respectively. Hydrocarbon presence ranged from petroliferous shale, to bituminous layering in shale hard beds, to hydrocarbon odour in limestone. Organic carbon content ranged from 0.5 to 2.5%, highest amount being present in the shale. Environmental DNA was extracted from core samples and PCR amplified using 16S rDNA bacterial primers. PCR performed with archaeal 16S rDNA and methanogen-specific (mcrA) primers did not yield DNA amplification. Gene analysis indicated that bacterial sequences similar to Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were present. Most sequences were not related to known cultivated species. Proteobacteria was the most dominant phyla at all depths and included heterotrophic, lithotrophic, acidophilic, radiotolerant, and sulphate-reducing species of bacteria. This study concludes that the observed biogenic methane is a product of ancient methanogenesis.
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Diagenesis of middle Ordovician rocks from the Lake Simcoe area, south-central OntarioMancini, Laura January 2011 (has links)
Middle Ordovician carbonates in the Lake Simcoe area, south-central Ontario were examined to determine if: (1) The δ18O values of early-stage calcite cement in hardgrounds are useful proxies for Ordovician seawater δ18O values; (2) a regional hydrothermal event affected middle Ordovician strata in the Lake Simcoe area. Whole rock samples of middle Ordovician hardgrounds and immediately overlying limestones containing early calcite cement have δ13C values ranging from -1.7 to +2.9‰ (PDB) and δ18O values ranging from -6.9 to -2.9‰ (PDB). Hardground δ18O values and the similarity of the isotopic composition between the hardgrounds and overlying limestones are consistent with diagenetic alteration during shallow burial, which indicates the hardgrounds are not useful proxies. Late-stage calcite cements have δ13C values from -8.4 to +2.9‰ (PDB) and δ18O values from -11.4 to -6.0‰ (PDB). Late-stage microcrystalline dolomites have δ13C values from -3.9 to +0.4‰ and δ18O values from -10.7 to -7.6‰. Late-stage saddle dolomites have δ13C values from -1.7 to 1.9‰ and δ18O values from -13.8 to -8.5‰. The late-stage carbonate δ18O values are more negative than the early-stage carbonate δ18O values and are interpreted to reflect progressively deeper burial diagenesis.
Four types of fluid inclusions were identified in late-stage calcite, saddle dolomite, barite, and quartz. Type 1 inclusions are aqueous liquid-rich with very consistent low to very low vapour-liquid ratios and are of primary, secondary pseudosecondary and indeterminate origins. Type 2 inclusions are aqueous liquid-only and are of primary and secondary origins. Type 3 inclusions are oil-bearing, liquid-rich with low to medium vapor-liquid ratios and are of secondary origin. Type 4 inclusions are vapour-only and are of indeterminate origin. The type 4 inclusions analyzed did not yield any microthermometric data suggesting they are empty cavities that have lost all their fluid.
Fluid inclusions of primary, secondary and pseudosecondary origins in calcite, dolomite and quartz have overlapping homogenization temperatures ranging from 43 to 188°C. Fluid inclusions of indeterminate origin in calcite and barite have homogenization temperatures from 80 to greater than 200°C. Petrographic and microthermometric evidence indicates that fluid inclusion homogenization temperatures greater than 150°C most likely are caused by stretching or leaking; therefore, are discounted. Fluid inclusion types 1 and 2 represent two fluid inclusion assemblages (FIA) based on final ice melting temperatures. The high salinity (10 to 30 wt%CaCl2) inclusions in FIA 1 are of primary, secondary, pseudosecondary and indeterminate origin in calcite, dolomite, barite and quartz. Fluid inclusions in FIA 1 are interpreted as reflecting saline basin brines from which the host minerals precipitated during burial diagenesis. The low salinity (0 to 2.7 wt%CaCl2) inclusions in FIA 2 are of secondary and indeterminate origin in calcite. Fluid inclusions in FIA 2 may reflect a meteoric origin such as in a vadose or phreatic environment based on inclusions containing different phases and variable vapor-liquid ratios. Alternatively the low salinity inclusions may reflect alteration from an influx of meteoric fluids that migrated through basement faults and fractures during periods of uplift and erosion.
Early and late-stage carbonates from this study precipitated from 18O-depleted pore fluids and/or at progressively higher temperatures accompanying deeper burial. The FIA 1 homogenization temperatures support burial diagenesis at 66 to 80°C if it is assumed the rocks were buried 2 km, the surface temperature was 20°C and the geothermal gradient was between 23 to 30°C/km.
An alternative interpretation is mineral precipitation during a regional hydrothermal event. Burial diagenesis does not explain the fluid inclusion homogenization temperatures of 90°C and greater unless geothermal gradients are higher than 35°C/km or burial depth is increased to 3 km or more. However, thermal maturity of organic matter in the Michigan Basin suggests Ordovician strata were never buried more than 2 km. Four models for regional hydrothermal fluid migration are: (1) gravity-driven flow; (2) ‘squeegee-type’ fluid flow; (3) convection cell fluid flow; and (4) structurally-controlled fluid flow. The gravity-driven model relies on continental heat flow and an influx of meteoric water from basin catchment areas. For the ‘squeegee, convection cell and structurally controlled models, hot fluids could have entered the region from several conduits concurrently during episodic reactivation of basement faults and fracture systems in response to intracratonic stresses created by the continuous interaction of tectonic plates. Determining which of the models best explains regional hydrothermal fluid flow in the Michigan Basin is difficult for several reasons; (1) surface temperatures and maximum burial temperatures at the time of mineral precipitation in the Michigan Basin during the Ordovician are unknown; (2) the timing of mineral precipitation in relation to tectonic pulses is undetermined; (3) there is as yet no known deep-seated heat sources in the Michigan Basin for convection to occur; and (4) it is unknown whether advection is a major process in the Michigan Basin. A collaborative multi-disciplinary research project covering geology, geophysics and hydrogeology would provide much more integrated data than is currently available from stable isotopes, fluid inclusions and organic matter.
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Ordovician (Billingen and Volkhov stages) Brachiopod Faunas of the East BalticEgerquist, Eva January 2004 (has links)
Lower-Middle Ordovician (Arenig) successions in the East Baltic have been investigated for more than one hundred and fifty years. Nevertheless detailed sampling still yields new species and better knowledge of the environment in which these organisms lived. The successions are well suited for bed by bed sampling because of the lack of tectonic disturbance and because the sequences are well documented. This study analyses collections of Billingen-Volkhov age mainly from the St. Petersburg region, but also from Estonia. A great deal of the material was obtained from the marly to clayey, soft sediment that intercalates the compact packstones and wackestones in the succession. Twenty-nine of these clay horizons were used for diversity estimates on the fauna through the succession. The most thoroughly investigated groups for this investigation were rhynchonelliformean brachiopods, conodonts and ostracodes. The results indicate that variances in diversity and abundance levels for these groups were not correlated, either to each other or to the small-scale sea level fluctuations that have been suggested for the region. However, diversity dynamics of brachiopods and ostracodes confirm the large-scale upward shallowing of the basin into the Upper Volkhov. Comparison with fossils from the limestones did not reveal any differences in faunal composition between the two preservation modes. The detailed sampling, coupled with sampling of the recently described mud mounds that occur in several outcrops, yielded large numbers of specimens. This enabled revision of earlier poorly known rhynchonelliformean genera such as Ujukella Andreev, as well as better known genera such as Porambonites Pander. In total the examined faunas include 31 genera assigned to 53 species of rhynchonelliformean brachiopods. Of these Leoniorthis and Eoporambonites are defined as new genera, and the following new species are described: Neumania paucicostata, Ranorthis rotunda, Orthidium gambolovensis, Orthidium lavensis, Skenidioides minutus, Tetralobula peregrina, Idiostrophia prima and Idiostrophia tenuicostata.
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Characterization of Bacterial Community Structure in Deep Subsurface Sedimentary Core Samples from Michigan Basin, OntarioIlin, Dimitri 10 January 2012 (has links)
Deep subsurface rock samples from Upper Ordovician strata in the Michigan Basin were analyzed for the presence of microbial communities. High concentrations of biogenic methane were observed in the Upper and Middle Ordovician formations. Total porosity values for the shale, shale hard bed and limestone samples were 7.4%, 2.5% and 1.9%, respectively. Hydrocarbon presence ranged from petroliferous shale, to bituminous layering in shale hard beds, to hydrocarbon odour in limestone. Organic carbon content ranged from 0.5 to 2.5%, highest amount being present in the shale. Environmental DNA was extracted from core samples and PCR amplified using 16S rDNA bacterial primers. PCR performed with archaeal 16S rDNA and methanogen-specific (mcrA) primers did not yield DNA amplification. Gene analysis indicated that bacterial sequences similar to Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were present. Most sequences were not related to known cultivated species. Proteobacteria was the most dominant phyla at all depths and included heterotrophic, lithotrophic, acidophilic, radiotolerant, and sulphate-reducing species of bacteria. This study concludes that the observed biogenic methane is a product of ancient methanogenesis.
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