Integrated sequence stratigraphy and geochemistry has significantly improved our knowledge of the formation and distribution of early and late diagenetic products in North American Mississippian carbonates. Deposition of the Madison Limestone occurred in concert with a major perturbation to the global C-pool, the timing of which was constrained by comparing secular variations in the delta13C values from the Madison Limestone with limited biostratigraphy. These early constraints were then improved by peak matching of 87Sr/86Sr values from this study with European brachiopod 87Sr/86Sr. The secular variations in the delta13C values were then applied as a chronostratigraphic tool to outcrops and subsurface core. As a result, our sequence stratigraphic interpretations and knowledge regarding lateral facies variability in carbonate rocks is significantly improved. Geographic variability in the magnitude of the delta13C values is also documented along the dip-transects which suggests that marine waters experienced increasing restriction in a landward direction. These results show how local changes to the C-pool are controlled by the morphology of the depositional system which can significantly affect the original signal of the global carbon pool. The geographic variability in the delta13C and delta18O values from reservoir quality dolomites along the mid-to-upper Madison ramp suggest they also precipitated from a restricted water mass with increased salinity, temperature and alkalinity which in turn, were responsible for the distribution of massive quantities of strataform dolomite deposited during the continental transgression at the beginning of the Mississippian. Trace element and 87Sr/86Sr values from strataform dolomite suggest initial formation from Mississippian seawater and slight resetting during shallow burial diagenesis. Petrography indicates that the formation of this dolomite ceased in the shallow burial environment, between the Mississippian and Permian. These dolomites are cross-cut by comparatively small volumes of geothermal-hydrothermal dolomite associated with Laramide-age breccias and fractures. Tectonic-hydrothermal activity associated with the Laramide Orogeny was responsible for late stage calcite cemented fractures and breccias which cross-cut all carbonate rocks discussed in this thesis. Radiogenic 87Sr/86Sr, depleted delta18O and enriched delta13C values and the hottest fluid inclusions measured in this study suggest the late stage calcite formed in the hydrothermal environment and under the most open-system and water-dominated conditions. Tectonic-diagenesis is ultimately responsible for establishing vertical barriers in the otherwise porous and permeable strataform dolomites.

The Tamengo Formation holds important and well preserved sedimentological and paleontological records of Upper Ediacaran Period. Previous works had centred on Corcal Mine, Saladeiro (now Sobramil Port) and Laginha Sections. However, there is no reports of detailed sedimentological and geochemical surveys on those and other outcrops of the Tamengo Formation at Corumbá-Ladário escarpment located at Paraguay River margins where the paleontological occurrences are concentrated. In the aim of contribute to the understanding of the paleo-environmental conditions, paleontological occurrences and its relationship at Tamengo Formation, detailed stratigraphic columns, description and interpretation of sedimentary facies, sampling, petrography, C and O isotope analysis along with other geochemical analysis were carried out on Corcal Mine, Sobramil Port and six new sections located along the Escarpment. From the obtained data, eight different facies and its C isotope signature were recognized: Wavy Bedding Mudstone (mean \'delta 13C, PDB\' =3.83%o PDB), Hummocky/Cross-Stratified Wackestone (mean \'delta 13C, PDB\' =3.98%o PDB), Cloudina Grainstone (mean \'delta 13C, PDB\' =4.36%o PDB), Intraclastic Packstone-Grainstone (mean \'delta 13C, PDB\' =4.19%o PDB), Low-Angle Cross-Laminated/Laminated Wackestone (mean \'delta 13C, PDB\'=4.93%o PDB), Cloudina Packstone (mean \'delta 13C, PDB\' =4.74%o PDB), Pelite, and Reworked Volcanic Tuff Facies, in which the Formation was dated by other authors, yielding an approximated age of 542 Ma. Also, very well-preserved C and O isotopic signatures were recognized. The carbon isotope data reveal more positive \'delta 13C, PDB\' values on coarser facies (Grainstone, Wackestone, Packstone) and in the calcareous beds overlying the Pelite facies, conforming six main distinctive patterns for carbonate facies that match with coarsening upwards cycles composing the Tamengo Formation. A ramp context of sedimentation has been interpreted for the Tamengo Formation, under strong storms influence, with a progressive tendency towards more positive \'delta 13C, PDB\' values from the deepest to shallower facies. A mid to outer ramp context was inferred for the Ladário-Corumbá, Goldfish, Sobramil and lower part of the Corcal Mine sections, with a mean \'delta 13C, PDB\' value of 3.97%o. For the mid part of the ramp two settings were interpreted; bioclastic lens represented by the Cloudina Grainstone and Intraclastic Packstone-Grainstone Facies and subcoastal setting, represented by the Low-Angle Cross-Laminated/Laminated Wackestone and Cloudina Packstone Facies with mean \'delta 13C, PDB\' values of \'delta 13C, PDB\' =4.33%o and \'delta 13C, PDB\' =4.87%o respectively, represented in the middle and upper part of the Corcal Mine Section. Also, the commonly addressed distribution of Cloudina and Corumbella on different facies could be the reflex of the oscillation between storms and fair-weather conditions; periodic influence of storm-waves or even typhoons in the ramp could avoid Cloudina fixation promoting constantly reworking and accumulating the shells on carbonate facies, while Corumbellas, probably restricted to deepest part of the ramp, expanded to the shallow parts of the ramp on fair weather conditions between storms, as settling by decantation of the Pelite Facies take place at the ramp, explaining the typic distribution of Cloudina restricted to carbonate facies and Corumbella to the interbedded Pelite Facies. / A Formação Tamengo possui importantes e bem preservados registros sedimentológicos e paleontológicos da parte superior do período Ediacarano. Trabalhos anteriores centraram-se nas secções das minas Corcal, Saladeiro (atual Porto Sobramil) e Laginha. No entanto, não há descrições de levantamentos sedimentológicos e geoquímicos detalhados sobre esses e outros afloramentos da Formação Tamengo na escarpa de Corumbá- Ladário, as margens do Rio Paraguai, onde as ocorrências paleontológicas estão concentradas. Com o objetivo de contribuir para o entendimento das condições paleoambientais, ocorrências paleontológicas e sua relação com a Formação Tamengo, perfis estratigráficos, amostragem, petrografia, análises de isótopos C e O e outras investigações geoquímicas foram realizadas na mina Corcal e Porto Sobramil e seis novas seções localizadas ao longo da referida escarpa. A partir dos dados obtidos, oito diferentes facies foram reconhecidas com suas respectivas assinaturas de isótopos de C: Wavy Bedding Mudstone (média \'delta 13C, PDB\'=3.83%o PDB), Hummocky/Cross-Stratified Wackestone (média \'delta 13C, PDB\' =3.98%o PDB), Cloudina Grainstone (média \'delta 13C, PDB\' =4.36%o PDB), Intraclastic Packstone-Grainstone (média \'delta 13C, PDB\' =4.19%o PDB), Low-Angle Cross-Laminated/Laminated Wackestone (média \'delta 13C, PDB\' =4.93%o PDB), Cloudina Packstone (média \'delta 13C, PDB\' =4.74%o PDB),Pelite e Reworked Volcanic Tuff Facies, na qual o topo da Formação Tamengo foi datada por outros autores, com idade aproximada de 542 Ma . Os valores de isótopos revelam valores de \'delta 13C, PDB\' mais positivos nas facies carbonáticas sobrepostas às Facies Pelito e nas de granulação mais grossa (Grainstone, Packstone, Wackstone), configurando seis padrões distintos para as fácies carbonáticas que coincidem, por sua vez, com os ciclos de raseamento ascendentes que compõem a Formação Tamengo. A Formação Tamengo tem sido interpretada como depositada em rampa carbonática sob ação de tempestades, onde se observa uma tendência para valores mais positivos do \'delta 13C, PDB\' das partes mais profundas para as partes rasas da rampa. Um contexto de rampa média para externa foi inferido para as seções Ladário-Corumbá, Goldfish, Sobramil e parte inferior da Mina Corcal, com um valor médio de \'delta 13C, PDB\' = 3,97 %o. Para a parte media da rampa, duas configurações foram interpretadas; lentes bioclásticos marcada pela presença das facies Cloudina Grainstone e Intraclastic Packstone-Grainstone e sublitoraneo marcada pela presença das facies Low-Angle Cross-Laminated/Laminated Wackestone e Cloudina Packstone, as duas configurações com valores médios de \'delta 13C, PDB\' = 4,33 e \'delta 13C, PDB\' = 4,87%o, respectivamente, representados na parte média e superior da Seção Mina Corcal. Além disso, a distribuição comumente observada de Cloudina e Corumbella em diferentes fácies poderia ser o reflexo da oscilação entre tempestades e condições de bom tempo; a influência periódica das ondas de tempestades ou possível tufões na rampa, teriam evitado a fixação das Cloudinas e promovido o constante retrabalhamento de suas caparaças, acumuladas nas fácies carbonáticas. Enquanto os Corumbellas provavelmente restritas às partes profundas da rampa, avançavam para as partes mais rasas durantes os intervalos das tempestades, quando se estabeleciam também, as condições de decantação de argila na rampa (Fácies Pelito), o que explicaria a típica distribuição de Cloudinas, apenas nas fácies carbonáticas, e Corumbella restritas às intercalações de pelitos.