Uma série de pesquisas realizadas em depósitos de sistemas fluviais, desenvolvidos anterior e concomitantemente à colonização dos continentes por vegetação, são aqui apresentadas com o intuito de investigar as principais características deposicionais destes sistemas, particularmente suas assembléias de fácies e elementos arquitetônicos preservados. Esta pesquisa busca, desta maneira, propor modelos deposicionais para sucessões fluviais pré-vegetação e contribuir para o avanço do conhecimento sobre as mudanças seculares em padrões de sedimentação, principalmente em relação à evolução dos rios através do tempo geológico. Estudos sedimentológicos foram realizados em depósitos fluviais da Formação Applecross do Grupo Torridon (Toniano, Escócia), Formação Guarda Velha do Grupo Guaritas (Cambriano, Brasil) e no Old Red Sandstone do Midland Valley (Siluriano-Carbonífero, Escócia). Foram empregadas análises de associações de fácies e arquitetura deposicional por meio de estudos de alto detalhe em afloramentos, combinadas a análises de paleocorrentes, de proveniência, e de estruturas de deformação sinsedimentar. Depósitos de canais fluviais meandrantes pré-vegetação com espessos depósitos de planícies de inundação ricos em sedimentos de granulação fina são pela primeira vez descritos em detalhe nos estudos aqui apresentados sobre depósitos da Formação Applecross. Diversas estruturas de deformação sinsedimentar encontradas na unidade acima referida são analisadas, revelando que seus estilos podem ser relacionados a diferentes regiões de uma planície fluvial. Nos depósitos da Formação Guarda Velha, é registrada a inter-relação entre dois sistemas fluviais coevos, cuja arquitetura deposicional contrastante resultou da diferente localização destes sistemas em relação à estrutura da bacia, assim como de diferentes áreas de captação. São relatados os efeitos de distintos controles deposicionais, como ambiente tectônico e regimes hidráulicos, sobre a arquitetura deposicional preservada em sistemas fluviais pré-vegetação. Esses dados demonstram que o estilo entrelaçado-em-lençol, apontado como o estilo pré-vegetação predominante, engloba na verdade uma variedade de diferentes estilos fluviais. Estudos em depósitos do Siluriano ao Carbonífero do Old Red Sandstone revelam o crescente impacto da vegetação sobre depósitos fluviais, particularmente o aumento exponencial de formação de paleosolos, além de mostrar semelhanças entre alguns destes sistemas com os sistemas pré-silurianos. A integração desses estudos revela que sistemas fluviais pré-vegetação são relativamente mais complexos do que previsto pelos modelos atualmente disponíveis. Importantemente, sugere que a escassez de sedimentos de granulção fina, preservados em depósitos fluviais pré-silurianos, está mais relacionada à baixa competência destes sistemas em preservar tais sedimentos do que à sua suposta ausência em ambientes pré-vegetação. Foi também desenvolvida uma metodologia específica para o uso de estruturas de deformação em sedimentos inconsolidados como ferramentas na reconstrução de paleoambientes, através das relações entre diferentes estilos deformacionais e ambientes deposicionais, possibilitando a indicação de regimes hidráulicos em depósitos fluviais e a informação indireta de taxas de atividades tectônicas em bacias. A integração de dados de sedimentologia com estudos específicos de deformação sinsedimentar é uma ferramenta útil na reconstrução paleoambiental de sistemas fluviais. / A series of studies were undertaken on fluvial systems deposits which developed prior to land-plant colonization, in order to investigate the main depositional characteristics of those systems, particularly their main facies assemblages and preserved depositional architecture. Main objectives are the proposal of depositional models for pre-vegetation fluvial systems, and the understanding of main secular changes in sedimentation processes and its influence on the evolution of rivers through geological times. Sedimentologic studies were undertaken in fluvial deposits from the Applecoss Formation of the Torridon Group (Tonian, NW Scotland), the Guarda Velha Formation (Cambrian, southern Brazil), and the Old Red Sandstone in the Midland Valley (Silurian-Carboniferous, NE Scotland). Highly-detailed sedimentary facies and depositional architecture analyses in outcrop scale were integrated with palaeocurrent and provenance studies, and soft-sediment deformation analysis. Pre-vegetation meandering channel deposits with relatively thick, fine-grained floodplain deposits from the Applecross Formation and here described for the first time. Analyses on sinsedimentary deformation structures preserved in the Applecross Formation reveal different styles which can be related to different parts of the fluvial plain. Studies on the Guarda Velha Formation revealed the inter-relationship between two coeval fluvial systems with markedly contrasting preserved depositional architecture, which developed as a result of the different location of the systems in relation to basin structure and different caption areas. The effects of different depositional controls on preserved pre-vegetation fluvial system architecture, such as tectonic environment and hydraulic regime, are recorded and interpreted. The present data demonstrate that the sheet-braided style, which is regarded as the prevailing fluvial style before the Silurian, in fact encompasses a varied number of different pre-vegetation fluvial styles. Studies on the Silurian to Early Carboniferous Old Red Sandstones in the Midland Valley of Scotland reveal the progressive impact of land plants on fluvial sedimentation, particularly the exponential increasing rates of soil production. Integration of the here presented data reveal that pre-vegetation fluvial styles. Studies on the Silurian to Early Carboniferous Old Red Sandstone in the Midland Valley of Scotland reveal the progressive impact of land plants on fluvial sedimentation, particularly the exponential increasing rates of soil production. Integration of the here presented data reveal that pre-vegetation fluvial systems are relatively more complex than previously described in the literature. Importantly, it suggests that the paucity of fine-grained sediments in pre-Silurian fluvial deposits is most likely related to various preservation issues than to the lack of such sediments. A particular methodology for the use of soft-sediment deformation structures as palaeoenvironmental tool was developed, allowing the interpretation of hydraulic regimes in fluvial deposits, indication of the basin\'s tectonic activity, and the relationship between different deformation styles and distinct depositional environments. The combined analyses of soft-sediment deformation structures and sedimentologic data is a powerful tool with which fluvial systems palaeoenvironmental can be reconstructed.

En Languedoc oriental, durant la fin du Néolithique final, on assiste à un accroissement important des occupations préhistoriques, en particulier au Néolithique final 3 (culture de Fontbouisse). Ce territoire a fait l’objet d’un découpage en faciès culturels, essentiellement sur la base des productions céramiques (Gutherz, 1975 ; 1990). La recherche s’est majoritairement concentrée sur les villages en pierre sèche des garrigues depuis les années 1950 jusqu’au début des années 1990. En effet, à partir de ces années-là, les investigations archéologiques se concentrèrent en plaine, sur des occupations à systèmes de fossés s’étendant sur plusieurs hectares. Le mobilier céramique, abondant, méritait une analyse plus poussée. Le travail présenté se penchera sur plusieurs séries céramiques des plaines datées du Néolithique final 3. La quantité massive de mobilier servira à vérifier si des régularités dans les productions céramiques peuvent être observées ou non. L’intérêt de ce travail est double : préciser les tendances stylistiques se dégageant des ensembles étudiés ; utiliser le contexte des successions de comblements stratigraphiques en vue d’affiner la chronologie de la production céramique et son évolution durant le Néolithique final 3. / In eastern Languedoc, during the late Neolithic, there has been a significant increase in prehistoric settlements, especially in the late Neolithic 3 (Fontbouisse culture). This area has been divided in cultural facies, mainly on the basis of ceramic production (Gutherz, 1975; 1990). Research has mostly focused on the garrigue’s dry stone villages from the 1950s to the early 1990s. Indeed, from those years, archaeological surveys have focused in plain, on ditch system settlements over several hectares. The abundant ceramicware deserved further analysis. This work will focus on several plain ceramic series dated to late Neolithic 3. The massive amount of ceramicware will make it possible to assess whether patterns in ceramic production can be observed. The value of this work is twofold: outline stylistic trends emerging from the sets studied, use the context of stratigraphic successions of fillings to refine the chronology of ceramic production and its evolution during late Neolithic 3.

The Frontier Formation in the Green River Basin of southwestern Wyoming consists of Late Cretaceous (Cenomanian-Turonian) marine and non-marine sandstones, siltstones, mudstones and coals deposited on the western margin of the Cretaceous Interior Seaway. Tight gas reservoirs exist in subsurface fluviodeltaic sandstones in the upper Frontier Formation (Dry Hollow Member) on the north-south trending Moxa Arch within the basin. These strata crop out in hogback ridges of the Utah-Idaho-Wyoming Thrust Belt approximately 40 km west of the crest of the Moxa Arch. Detailed, quantitative outcrop descriptions were constructed using emerging photogrammetric techniques along with field observations and measured sections at five key outcrop localities along the thrust belt. Understanding the architectural style of this low net-to-gross fluvial system allows for improved reservoir prediction in this and other comparable basins. The architectural style of the Dry Hollow Member fluvial deposits varies vertically as the result of a relative shoreline transgression during Dry Hollow deposition. Amalgamated conglomerates and associated fine to coarse sandstones near the base of the section and much thinner, isolated sandstones near the top of the Dry Hollow occur in laterally extensive units that can be identified over tens of kilometers. These units also provide means to relate outcrop and subsurface stratigraphic architecture. Combined with available subsurface data, fully-realized 3D static reservoir models for use as analogs in subsurface reservoir characterization may be constructed. Grain size, reservoir thickness and connectivity of fluvial sandstones is generally greatest near the base of this member and decreases upward overall. Despite relative isolation of some channel bodies, geocellular facies modeling indicates good lateral and vertical connectivity of most channel sandstones. The Kemmerer Coal Zone, with little sandstone, divides lower and upper well-connected sandy units.

At head of title: National Centre for Petroleum Geology and Geophysics. / CD-ROM contains Appendices (1-10) in PDF. / Includes copies of papers co-authored by the author. / Includes bibliographical references (leaves [471]-499 in vol. 2) / System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader. / 2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

If mitigation measures are not made to prevent global warming the consequences of a continued global climate change, caused by the use of fossil fuels, may be severe. Carbon Capture and Storage (CCS) has been suggested as a way of decreasing the global atmospheric emission of CO2. In the realms of MUSTANG, a four year (2009-2013) large-scale integrating European project funded by the EU FP7, the objective is to gain understanding of the performance as well as to develop improved methods and models for characterizing so- called saline aquifers for geological storage of CO2. In this context a number of sites of different geological settings and geographical locations in Europe are also analyzed and modeled in order to gain a wide understanding of CO2 storage relevant site characteristics. The south Scania site is included into the study as one example site with data coming from previous geothermal and other investigations. The objective of the Master's thesis work presented herein was to construct a 3D model for the south Scania site by using modeling/simulation software Petrel, evaluate well log data as well as carry out stochastic simulations by using different geostatistical algorithms and evaluate the benefits in this. The aim was to produce a 3D model to be used for CO2 injection simulation purposes in the continuing work of the MUSTANG project. The sequential Gaussian simulation algorithm was used in the porosity modeling process of the Arnager greensand aquifer with porosity data determined from neutron and gamma ray measurements. Five hundred realizations were averaged and an increasing porosity with depth was observed.   Two different algorithms were used for the facies modeling of the alternative multilayered trap, the truncated Gaussian simulation algorithm and the sequential indicator simulation algorithm. It was seen that realistic geological models were given when the truncated Gaussian simulation algorithm was used with a low-nugget variogram and a relatively large range. / Den antropogena globala uppvärmningen orsakad av användandet av fossila bränslen kan få förödande konsekvenser om ingenting görs. Koldioxidavskiljning och lagring är en åtgärd som föreslagits för att minska de globala CO2-utsläppen. Inom ramarna för MUSTANG, ett fyra år långt (2009-2013) integrerande projekt finansierat av EU FP7 (www.co2mustang.eu), utvecklas metoder, modeller och förståelse angående så kallade saltvattenakviferers lämplighet för geologisk koldioxidlagring. En del av projektet är att analysera ett antal representativa formationer i olika delar av Europa för att få kunskap angående förekommande koldioxidlagringsspecifika egenskaper hos saltvattenakviferer. Ett av områdena som har inkluderats är i sydvästra Skåne. Syftet med detta examensarbete var att konstruera en 3D modell över detta område med hjälp av modellerings/simuleringsprogrammet Petrel, utvärdera borrhålsdata samt genomföra stokastiska simuleringar med olika geostatistiska algoritmer och utvärdera dem. Målsättningen var att konstruera en modell för CO2 injiceringssimuleringar i det forstsatta arbetet inom MUSTANG-projektet. En algoritm av sekventiell Gaussisk typ användes vid porositetsmodelleringen av Arnager Grönsandsakviferen med porositetsdata erhållen från neutron- och gammastrålningsmätningar. Ett genomsnitt av femhundra realisationer gjordes och en porositetstrend som visade en ökning med djupet kunde åskådligöras. Två olika algoritmer användes vid faciesmodelleringen av den alternativa flerlagrade fällan: en algoritm av trunkerade Gaussisk typ och en sekventiell indikatorsimuleringsalgoritm. Resultaten tyder på att en realistisk geologisk modell kan erhållas vid användandet av den trunkerande algoritmen med ett låg-nugget variogram samt en förhållandevis lång range.

At head of title: National Centre for Petroleum Geology and Geophysics. / CD-ROM contains Appendices (1-10) in PDF. / Includes copies of papers co-authored by the author. / Includes bibliographical references (leaves [471]-499 in vol. 2) / System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader. / 2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

During the Late Pliocene and early Pleistocene, when the paleo-Orinoco delta system transited over the Amacuro Shelf and reached the paleo-shelf-break along the southeastern shoreline of Trinidad. At this time onwards, the shelf-edge delta clinoforms developed further eastward. These deltaic clastic wedges serve as the unique analog in the geological record for an accommodation-driven inner-shelf and shelf-edge delta, developed at an oblique foreland tectonic setting situated at a tropical-equatorial paleogeographic setting. These deposits were influenced by strong Atlantic longshore current, tropical storms, and phytodetrital pulses, and with an exceptionally high sediment accumulation rates. These four aspects make the clastic wedges unique candidates for sedimentological, ichnological, and stratigraphic investigation. The primary objectives of this thesis are to: (a) collect, analyze, and integrate outcrop data on lithofacies, trace fossils, and discontinuity surfaces into a comprehensive depositional and ichnological model for the first growth-fault-guided shelf-marginal pulse of the paleo-Orinoco delta, as recorded in the Mayaro Formation outcrops in southeast Trinidad; and (b) deduce the dominant sedimentary processes during the across shelf transit and their impacts on the benthic infauna as preserved in the Morne L’Enfer Formation outcrops of southwest Trinidad, which are possibly slightly older than the Mayaro Formation. The basal interval of the Morne L’Enfer Formation has specifically been investigated for this purpose, where the deltaic clastic wedges are preserved directly above shelf deposits. The entire Mayaro Formation megasequence is categorized into deposits belonging to twelve different subenvironments based on lithofacies associations and ichnological characteristics. Ichnological evidence indicates that the shelf-edge deltas are one of the most extreme marine environments for benthic metazoans to colonize. However, the combinations and ranking of stress factors affecting the colonizing fauna are diverse and distinct in every individual subenvironment indicating the relative dominances of river-influence, waves, and/or sediment-gravity-flows vis-à-vis slope instability. Due to variations in stress factors, the megasequence also displays dual ichnologic and sedimentologic properties of both the shelf-edge delta lobe(s) and the outer shelf delta lobe(s). A minor transient tidal influence can only be observed in the architectural elements, e.g. elongated interbar embayment and interlobe prodeltaic depocentres, which control topography and enhance tidal effect. Discovery of an unusual monospecific Glossifungites Ichnofacies along an incision surface in the midst of the Mayaro Formation succession enabled a substantial overhaul of the earlier understanding of the formation in terms of its depositional model and stacking pattern. The surface has been re-identified as a canyon/gully cut at the shelf-edge, which possibly acted as a conduit for (a) the mass movements and for (b) the coarse clastic (mostly silt to medium-grained sand) sediment transfer to deep marine settings. The monospecific nature of the Glossifungites Ichnofacies suite indicates that the incision surface was under substantial ecological stresses for the colonizing infauna. The stresses might have arisen from slope instability of the steep canyon/gully walls, mass movements above the incision surface, elevated water turbulence, and lowered salinity from river influx. Five different facies tracts have been identified within the canyon/gully-fill, which crosscuts the shelf-edge delta-front. The facies tracts are dominated by different types of sediment-gravity flow deposits, which are systematically stacked and are almost devoid of trace fossils due to rapid sedimentation rates and slope instability. They are also strikingly different from the surrounding deltaic facies. A high-frequency sequence stratigraphic model involving the influence of growth-fault tectonics on the relative sea-level curve has been invoked to explain the incision of the canyon/gully and its sequential filling processes. On the other hand, the transition from the open shelf to inner-shelf deltaic condition as displayed by the basal members of the Morne L’Enfer Formation is strongly dominated by evidences of river influence with the transient background action of fair-weather waves and storm waves. A peculiar pattern of disappearance of trace fossils produced by irregular sea-urchins highlight that the river influence was quite strong not only at the sediment-water interface but also in the water-column, which affected invertebrate larvae. The initial progradation of the clastic wedge on the shelf was dominated by hyperpycnal flows and waves in contrast to tidal domination in the younger members of the formation.

Cette recherche vise à proposer une synthèse de la céramique chez les Bituriges Cubes aux deux derniers siècles avant notre ère. Elle est fondée sur l'analyse détaillée du matériel inédit de deux agglomérations bituriges, Châteaumeillant/Medio/anum et Bourges/Avaricum (Cher), qui sont par ailleurs mis en perspective avec les ensembles publiés de Levroux (Indre). À travers l'établissement d'une typologie régionale et l'analyse technique et fonctionnelle du mobilier céramique, l'objectif poursuivi est double. Il s'agit, en premier lieu, d'appréhender la dynamique chronologique de l'habitat groupé biturige, c'est-à-dire les différents rythmes et processus de création, d'évolution ou d'abandon qu'ont pu enregistrer les agglomérations depuis leur émergence jusqu'à l'intégration de la cité biturige à l'empire romain. En second lieu, différents aspects socio-économiques et culturels perceptibles par le biais des données céramologiques sont examinés. Cette approche multiple apporte ainsi un éclairage nouveau sur la société biturige pendant cette période charnière où la Gaule du centre est soumise aux contacts et à l'influence du monde méditerranéen / This research offers an overview of the Bituriges Cubi's ceramic during the two centuries before AD. It is based on the detailed analysis of new material originate from Chateaumeillant/Medio/anum and Bourges/Avaricum (Cher). These two urban sites have also been put into perspective in published sets of Levroux (lndre). A dual objective is pursued through the establishment of a regional typology and the functional and technical analysis of ceramics material. On one hand, it is about comprehending the chronological dynamic of the bituriges grouped settlements, since the emergence of the opened urban area to the creation of oppida and their evolution to the Biturige's city integration to the Roman Empire. On the other hand, it broaches the different socio-economic and cultural aspects perceptible through ceramological data. Thus, this multi-faceted approach sheds a new light on the Biturige society during this transitional period where central Gaul is subject on contacts and influence of the Mediterranean world

Made available in DSpace on 2015-03-13T17:08:38Z (GMT). No. of bitstreams: 1 FilipeSL_DISSERT.pdf: 18861623 bytes, checksum: dec06565f69ab3657111750b25f78441 (MD5) Previous issue date: 2013-06-27 / The Camorim Oilfield, discovered in 1970 in the shallow water domain of the Sergipe Sub-basin, produces hydrocarbons from the Carm?polis Member of the Muribeca Formation, the main reservoir interval, interpreted as siliciclastics deposited in an alluvial-fluvial-deltaic context during a late rifting phase of Neoaptian age, in the Sergipe-Alagoas Basin. The structural setting of the field defines different production blocks, being associated to the evolution of the Atalaia High during the rift stage and subsequent reactivations, encompassing NE-SW trending major normal faults and NWEW trending secondary faults. The complexity of this field is related to the strong facies variation due to the interaction between continental and coastal depositional environments, coupled with strata juxtaposition along fault blocks. This study aims to geologically characterize its reservoirs, to provide new insights to well drilling locations in order to increase the recovery factor of the field. Facies analysis based on drill cores and geophysical logs and the 3D interpretation of a seismic volume, provide a high resolution stratigraphic analysis approach to be applied in this geodynamic transitional context between the rift and drift evolutionary stages of the basin. The objective was to define spatial and time relations between production zones and the preferential directions of fluid flow, using isochore maps that represent the external geometry of the deposits and facies distribution maps to characterize the internal heterogeneities of these intervals, identified in a 4th order stratigraphic zoning. This work methodology, integrated in a 3D geological modelling process, will help to optimize well drilling and hydrocarbons production. This methodology may be applied in other reservoirs in tectonic and depositional contexts similar to the one observed at Camorim, for example, the oil fields in the Aracaju High, Sergipe Sub-basin, which together represent the largest volume of oil in place in onshore Brazilian basins / O Campo de Camorim, descoberto em 1970 na por??o de ?guas rasas da Subbacia de Sergipe, produz hidrocarbonetos do Membro Carm?polis/Forma??o Muribeca, principal intervalo reservat?rio, interpretado como silicicl?sticos depositados em um contexto al?vio-fl?vio-deltaico na fase tardia do rifteamento da Bacia Sergipe-Alagoas, Neoaptiano. O arcabou?o estrutural, que subdivide o campo em blocos produtores, est? associado ? evolu??o do Alto de Atalaia durante a fase rifte e reativa??es posteriores, apresentando falhas normais principais de dire??o NE-SW e falhas secund?rias de dire??es NW-SE e E-W. A complexidade do campo est? ligada ? intensa varia??o faciol?gica, resultante da intera??o entre os ambientes deposicionais continentais e costeiros, e a justaposi??o dos estratos associada ? evolu??o estrutural. Este trabalho tem como objetivo a caracteriza??o geol?gica dos reservat?rios para dar subs?dios ?s novas perfura??es de po?os destinados a aumentar o fator de recupera??o do campo. Deste modo, a partir da an?lise faciol?gica realizada em testemunhos e perfis geof?sicos, em conjunto com a interpreta??o do volume s?smico 3D, prop?e-se uma metodologia que se baseia na an?lise estratigr?fica de alta resolu??o, aplicada em um contexto geodin?mico transicional entre os est?gios rifte e drifte de evolu??o da bacia, capaz de determinar as rela??es espaciais e temporais das zonas produtoras e as dire??es preferenciais do fluxo de fluidos, empregando para este fim, mapas de is?coras que representam a geometria externa, e mapas de distribui??o de f?cies para as heterogeneidades internas destes intervalos identificados em um zoneamento estratigr?fico de 4? ordem. Esta metodologia de trabalho, integrada em um processo de modelagem geol?gica 3D, vai ser utilizada para estabelecer a geometria da malha de po?os injetores/produtores do intervalo de interesse e pode ser aplicada em outros reservat?rios cujo contexto tect?nico-deposicional seja semelhante ao observado em Camorim, caso dos campos localizados no Alto de Aracaju, Sub-bacia de Sergipe, que juntos comp?em o maior volume de ?leo in place na por??o terrestre das bacias brasileiras

Uma série de pesquisas realizadas em depósitos de sistemas fluviais, desenvolvidos anterior e concomitantemente à colonização dos continentes por vegetação, são aqui apresentadas com o intuito de investigar as principais características deposicionais destes sistemas, particularmente suas assembléias de fácies e elementos arquitetônicos preservados. Esta pesquisa busca, desta maneira, propor modelos deposicionais para sucessões fluviais pré-vegetação e contribuir para o avanço do conhecimento sobre as mudanças seculares em padrões de sedimentação, principalmente em relação à evolução dos rios através do tempo geológico. Estudos sedimentológicos foram realizados em depósitos fluviais da Formação Applecross do Grupo Torridon (Toniano, Escócia), Formação Guarda Velha do Grupo Guaritas (Cambriano, Brasil) e no Old Red Sandstone do Midland Valley (Siluriano-Carbonífero, Escócia). Foram empregadas análises de associações de fácies e arquitetura deposicional por meio de estudos de alto detalhe em afloramentos, combinadas a análises de paleocorrentes, de proveniência, e de estruturas de deformação sinsedimentar. Depósitos de canais fluviais meandrantes pré-vegetação com espessos depósitos de planícies de inundação ricos em sedimentos de granulação fina são pela primeira vez descritos em detalhe nos estudos aqui apresentados sobre depósitos da Formação Applecross. Diversas estruturas de deformação sinsedimentar encontradas na unidade acima referida são analisadas, revelando que seus estilos podem ser relacionados a diferentes regiões de uma planície fluvial. Nos depósitos da Formação Guarda Velha, é registrada a inter-relação entre dois sistemas fluviais coevos, cuja arquitetura deposicional contrastante resultou da diferente localização destes sistemas em relação à estrutura da bacia, assim como de diferentes áreas de captação. São relatados os efeitos de distintos controles deposicionais, como ambiente tectônico e regimes hidráulicos, sobre a arquitetura deposicional preservada em sistemas fluviais pré-vegetação. Esses dados demonstram que o estilo entrelaçado-em-lençol, apontado como o estilo pré-vegetação predominante, engloba na verdade uma variedade de diferentes estilos fluviais. Estudos em depósitos do Siluriano ao Carbonífero do Old Red Sandstone revelam o crescente impacto da vegetação sobre depósitos fluviais, particularmente o aumento exponencial de formação de paleosolos, além de mostrar semelhanças entre alguns destes sistemas com os sistemas pré-silurianos. A integração desses estudos revela que sistemas fluviais pré-vegetação são relativamente mais complexos do que previsto pelos modelos atualmente disponíveis. Importantemente, sugere que a escassez de sedimentos de granulção fina, preservados em depósitos fluviais pré-silurianos, está mais relacionada à baixa competência destes sistemas em preservar tais sedimentos do que à sua suposta ausência em ambientes pré-vegetação. Foi também desenvolvida uma metodologia específica para o uso de estruturas de deformação em sedimentos inconsolidados como ferramentas na reconstrução de paleoambientes, através das relações entre diferentes estilos deformacionais e ambientes deposicionais, possibilitando a indicação de regimes hidráulicos em depósitos fluviais e a informação indireta de taxas de atividades tectônicas em bacias. A integração de dados de sedimentologia com estudos específicos de deformação sinsedimentar é uma ferramenta útil na reconstrução paleoambiental de sistemas fluviais. / A series of studies were undertaken on fluvial systems deposits which developed prior to land-plant colonization, in order to investigate the main depositional characteristics of those systems, particularly their main facies assemblages and preserved depositional architecture. Main objectives are the proposal of depositional models for pre-vegetation fluvial systems, and the understanding of main secular changes in sedimentation processes and its influence on the evolution of rivers through geological times. Sedimentologic studies were undertaken in fluvial deposits from the Applecoss Formation of the Torridon Group (Tonian, NW Scotland), the Guarda Velha Formation (Cambrian, southern Brazil), and the Old Red Sandstone in the Midland Valley (Silurian-Carboniferous, NE Scotland). Highly-detailed sedimentary facies and depositional architecture analyses in outcrop scale were integrated with palaeocurrent and provenance studies, and soft-sediment deformation analysis. Pre-vegetation meandering channel deposits with relatively thick, fine-grained floodplain deposits from the Applecross Formation and here described for the first time. Analyses on sinsedimentary deformation structures preserved in the Applecross Formation reveal different styles which can be related to different parts of the fluvial plain. Studies on the Guarda Velha Formation revealed the inter-relationship between two coeval fluvial systems with markedly contrasting preserved depositional architecture, which developed as a result of the different location of the systems in relation to basin structure and different caption areas. The effects of different depositional controls on preserved pre-vegetation fluvial system architecture, such as tectonic environment and hydraulic regime, are recorded and interpreted. The present data demonstrate that the sheet-braided style, which is regarded as the prevailing fluvial style before the Silurian, in fact encompasses a varied number of different pre-vegetation fluvial styles. Studies on the Silurian to Early Carboniferous Old Red Sandstones in the Midland Valley of Scotland reveal the progressive impact of land plants on fluvial sedimentation, particularly the exponential increasing rates of soil production. Integration of the here presented data reveal that pre-vegetation fluvial styles. Studies on the Silurian to Early Carboniferous Old Red Sandstone in the Midland Valley of Scotland reveal the progressive impact of land plants on fluvial sedimentation, particularly the exponential increasing rates of soil production. Integration of the here presented data reveal that pre-vegetation fluvial systems are relatively more complex than previously described in the literature. Importantly, it suggests that the paucity of fine-grained sediments in pre-Silurian fluvial deposits is most likely related to various preservation issues than to the lack of such sediments. A particular methodology for the use of soft-sediment deformation structures as palaeoenvironmental tool was developed, allowing the interpretation of hydraulic regimes in fluvial deposits, indication of the basin\'s tectonic activity, and the relationship between different deformation styles and distinct depositional environments. The combined analyses of soft-sediment deformation structures and sedimentologic data is a powerful tool with which fluvial systems palaeoenvironmental can be reconstructed.