Accessibility to consistent subsurface hydrostratigraphic information is crucial for the development of robust groundwater flow and contaminant transport models. However, full three-dimensional understanding of the subsurface geology is often the missing link. Construction of watershed-scale hydrostratigraphic models continues to be limited by the quality and density of borehole data which often lack detailed geologic information. This can become a serious problem where rapid sediment facies changes and intricate sediment architecture occur. This research is motivated by the idea that if we can understand more about the distribution of sediments and structures of complex deposits, we learn more about depositional processes and how they affect the internal geometry of a deposit and the distribution of hydraulic properties. One approach is to study surficial excavations (e.g. sand and gravel pits) that often punctuate shallow aquifers. The purpose of this study is to develop and test a method of integrating high-resolution georeferenced stratigraphic and sedimentologic information from sand and gravel pits as a means to better document sedimentologic data and improve understanding of the depositional environments. The study area is located within the Waterloo Moraine, in southwestern Ontario, and is an unconsolidated shallow aquifer system with a complex internal architecture and sediment heterogeneity. The method involves the integration of high-resolution field data with borehole and geophysical information in a computer-based 3D environment. A total of fourteen virtual sedimentary sections were constructed by georegistering digital photographs within a framework of georeferenced positions collected using a reflectorless total station and GPS. Fourteen sediment facies have been described in the field. These include crudely stratified gravel beds, planar and cross-laminated sandy strata (ripple and dune scales), along with laminated and massive silty and clayey beds. Calculated hydraulic conductivities span over seven orders of magnitude. The analysis of a single excavation has shown contrasting sediment assemblages from one end of the pit to the other, highlighting the complexity of the Waterloo Moraine. The heterogeneous and deformed layers of gravel, sand, and mud may be the product of an ice-contact to ice-proximal environment, whereas the extensive sandy assemblages may reflect an intermediate subaqueous fan region. The results also suggest that the borehole database overestimates the amount of fine-grained material in the study area. Finally, this research demonstrates that it is possible to build in a timely manner a 3D virtual sedimentologic database. New emerging technologies will lead to increased resolution and accuracy, and will help streamline the process even further. The possibility of expanding the 3D geodatabase to other excavations across the region in a timely manner is likely to lead to improved hydrostratigraphic models and, by extension, to more efficient strategies in water resources planning, management and protection.

Studies examining bioevents (e.g., mass extinctions, faunal turnovers, diversification events) usually only scrutinize a short interval prior to such events, however, understanding their actual paleobiological implications requires a thorough understanding of the background conditions. The objective of this study is to document the background biodiversity dynamics in a single lithofacies of the Upper Cretaceous Pierre Shale that was deposited in an offshore setting of the Western Interior Seaway (WIS) and to place these changes into an environmental context. To assess the background biodiversity dynamics, the concretionary faunas of the Baculites eliasi through B. clinolobatus biozones of the Pierre Shale in eastern Wyoming were examined to understand the structure of marine habitats in the WIS through an interval of ~2.5 Ma. Both changes in the taxonomic composition of assemblages and the relative abundance of the various species are interpreted to reflect ecological and environmental change through the study interval. The concretionary faunas are thought to represent relatively short-term, time-averaged accumulations of dead and living animals on the muddy sea floor of the WIS that were concentrated by storm or current activity. They are likely accurate representations of the original skeletonized fauna of the WIS. The samples with lower diversity and abundances show a relationship with intervals when water conditions were deepest and the paleoshoreline was furthest to the west, while higher diversity and abundances match periods when the paleoshoreline was the closest and shallow-water conditions prevailed in that part of the WIS. The decrease in diversity with depth can best be explained by the long-term presence of dysoxic/anoxic conditions that would have precluded benthic faunas. The distribution of taxa and diversity of the assemblages seen in the study interval most likely reflect migrating oxygen-controlled biofacies in the WIS that were responding to changes in depth and the proximity to the western shoreline that was in turn controlled by relative sea-level fluctuations. This analysis shows that significant changes in richness, abundance, and guild structure can arise in response to variations in sea level with no apparent changes in lithology. It is also shown that a lack of environmental context can significantly influence interpretations of paleobiological and paleoecological data and it is recommended that future lines of research should examine faunal, morphological, and ecological change in a time/environmental context.

No description available.

No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2014. / The Karasburg Basin is situated in southern Namibia and preserves a heterogeneous succession of Karoo Supergroup strata up to 1000m thick. The uppermost preserved succession in this basin is the Amibberg Formation which is 250m thick and consists of intervals of sandstone, siltstone and mudstone. This study uses facies analysis, sequence stratigraphy and petrography to determine the palaeogeography and provenance for the Amibberg Formation. This is then used to establish environmental variability across the Karasburg – Aranos – Main Karoo basins and to define an equivalent of the Amibberg Formation in the Main Karoo Basin. Detailed stratigraphic logging of five outcrop localities has led to the identification of seven distinct lithofacies and two dominant ichnofacies (Cruziana and Skolithos). These lithofacies include: 1) Massive, laminated and bioturbated mudstones interpreted as offshore deposits (OS); 2) Bioturbated siltstones and sandstones which are representative of offshore-transitional environments (OST); 3) Interbedded sandstones and siltstones also interpreted as offshore-transitional deposits (OST) and generated by river-fed hyperpycnal plumes; 4) Sharp based, massive sandstones interpreted as being deposited on the distal lower shoreface (dLSF); 5) Non-amalgamated hummocky cross-stratified (HCS) and wave rippled sandstones interpreted as distal lower shoreface deposits (dLSF); 6) Amalgamated HCS and wave rippled sandstones interpreted as proximal lower shoreface deposits (pLSF); and 7) Soft-sediment deformed (SSD) sandstones and siltstones occurring in close juxtaposition with dLSF and pLSF deposits. The vertical arrangement of these lithofacies shows a general coarsening and shallowing upward trend. Overall the rocks of the Amibberg Formation consist of wave-dominated shoreface deposits with significant influence by tidal processes. Petrographically, the sandstone samples fall into the class of quartz and feldspathic wackes and are sourced from craton interior provenances. Geochemical analysis of mudstones and nodules indicate high levels of microbial activity under predominantly oxic conditions during the deposition of the Amibberg Formation. Five poorly defined 4th order T-R cycles are observable within the strata of the Amibberg Formation. Large regressive intervals are capped by thin transgressive tracts and these cycles are interpreted to have formed due to eustatic processes. Overall, the Amibberg Formation represents a regressive shoreline. iii Based on the mean palaeocurrent vectors a NNE-SSW palaeoshoreline orientation is deduced and the shoreface must have occupied a palaeohigh on the northern side of the western Cargonian Highlands. This emergent highland acted as an extensive headland and assisted in the connectivity of the Karasburg and Aranos basins, with partial connectivity with the Main Karoo Basin during the Early Permian. Based on this study, the Amibberg Formation is considered an equivalent of the Waterford Formation in the Main Karoo Basin based on similar: stratigraphic position; thickness; sedimentary structures; trace fossil assemblages and stacking patterns.

The Boacica Member of the Batinga Formation, in the Sergipe-Alagoas basin, occurs on the high structural Japoatã (SE), Penedo and Palmeira Alta (AL), characterized by rhythmic intercalation of laminated siltstones, shales and very fine sandstones, assigned to a system depositional deltaics fronts and prodeltas. Despite very poor fossiliferous content, some analyzes recovered palynomorphs characteristic from the Eo Mesopennsylvanian (Neocarboniferous), and some levels are locally abundant ichnofossils. Ichnological associations are poorly diversified, represented by traces of rest or locomotion. The discovery of trace fossils associated with the emergence of new outcrops, allowed the new studies lithostratigraphic and paleontological detailed in this unit. This study had to perform the characterization lithostratigraphic and paleontological in two outcrops of this unit, Batinga 5 and Pescocinho 3. The sections are characterized by rhythmic intercalations of shales, siltstones laminated and massives of whitish gray color, with very fine sandstones cream colored, sometimes showing cyclical patterns of coarsening upward prays fining upward reflecting changes in the depositional process. The sandstones generally show structures climbing-ripples. According to the stratigraphic succession raised in these outcrops, eight sedimentary facies were observed, confirming that the deposits of facies suggest prodelta, delta front, turbidite lobes, lake bottom, fluvial, crevasses and the debris englaciais. The ichnofossils were observed along some facies and analyzed in different lithologies (shales, siltstones and sandstones) but are not as abundant in Batinga 5. The ichnofossils presented themselves as bioturbation structures, featuring brands resting, locomotion and pasture. Traces are reduced sizes and present as bilobates thrails, straight or curved, oval, in a "coffee beans" form and other tracks irregular with random crossing. The traces were classified as belonging to the ichnospecie Isopodichnus problematica Schindewolf, 1921 and ichnogenus Rusophycus Hall, 1852, Helminthoidichnites Fitch, 1850, Aulichnites Fenton & Fenton, 1937, are more common in siltstones and shales. The ichnospecie Paganzichnus carboniferus Pazos, 2000 together with ichnogenus Gordia Emmons, 1844 and Scoyenia White, 1929, are more common in sandy prodeltaic facies, although also found in siltstones-shale facies. Probably these traces were generated by activities of the arthropods, branchiopods crustaceans and organisms nematomorph. It was also verified that one morphotype was named as Morphotype A . This morphotype displays small short lines with elongated shapes, with a straight path to curve slightly, with differents directions and is preserved in convex hyporelief or concave epirelief both being frequent in muddy facies prodeltaics as in sandy facies of deltaic front. The association of the traces studied here features a subaqueous environment, muddy, shallow and relatively calm may represent the ichnofacies Mermia (lake) and Scoyenia (transitional). / O Membro Boacica da Formação Batinga, da bacia de Sergipe-Alagoas, ocorre entre os altos estruturais de Japoatã (SE), Penedo e Palmeira Alta (AL), sendo caracterizado pela intercalação rítmica de siltitos laminados, folhelhos e arenitos muito finos, atribuídos a um sistema deposicional de frentes deltaicas e prodeltas. Apesar do conteúdo fossilífero ser muito pobre, algumas análises recuperaram palinomorfos característicos do Eo a Mesopensilvaniano (Neocarbonífero), e alguns níveis são localmente abundantes em icnofósseis. As associações icnológicas são pouco diversificadas, representadas por icnitos de repouso ou locomoção. A descoberta de icnofósseis, associada ao surgimento de novos afloramentos, favoreceu a realização de novos estudos litoestratigráficos e paleontológicos mais detalhados nesta unidade. Esse estudo teve como principal objetivo realizar a caracterização litoestratigráfica e paleontológica em dois afloramentos desta unidade, Batinga 5 e Pescocinho 3. As seções caracterizam-se por intercalações rítmicas de folhelhos, siltitos laminados e maciços de coloração cinza esbranquiçada, com arenitos muito finos de coloração creme, exibindo padrões cíclicos ora de coarsening upward ora de fining upward refletindo mudanças no processo deposicional. Os arenitos de maneira geral apresentam estruturas de climbing-ripples. De acordo com sucessões estratigráficas levantadas nestes afloramentos, oito fácies sedimentares foram observadas, constatando-se que os depósitos sugerem fácies de prodelta, frente deltaica, lobos turbidíticos, fundo de lago, crevasses, fluviais e detritos englaciais. Os icnofósseis foram observados ao longo de algumas fácies analisadas e em diferentes litotipos (folhelhos, siltitos e arenitos), porém não são tão abundantes em Batinga 5. Os icnofósseis apresentaram-se como estruturas de bioturbação, caracterizando icnitos de repouso, locomoção e pastagem. As pistas são de tamanhos reduzidos apresentando-se como pistas bilobadas, retas ou curvas, ovaladas, impressões em forma de grãos de café e outras pistas irregulares com cruzamentos aleatórios. Os traços que foram classificados como pertencentes à icnoespécie Isopodichnus problematicus Schindewolf, 1921 e aos icnogêneros Rusophycus Hall, 1852, Helminthoidichnites Fitch, 1850 e Aulichnites Fenton & Fenton, 1937 são mais frequentes nos siltitos e folhelhos. A icnoespécie Paganzichnus carboniferus Pazos, 2000 juntamente com os icnogêneros Gordia Emmons, 1844 e Scoyenia White, 1929 são mais frequentes nas fácies arenosas do prodelta, embora também sejam encontrados em fácies sílticosargilosas. Provavelmente, esses traços foram gerados por atividades de artrópodes, crustáceos branquiópodos e organismos nematomorfos. Também foi verificado um morfotipo não identificado nomeado Morfotipo A que exibe pequenos traços curtos com formas alongadas, com uma trajetória reta a pouco curva, com direções variadas e estão preservados em hiporrelevo convexo ou epirrelevo côncavo estando frequentes tanto em fácies lamosas prodeltaicas quanto em fácies arenosas da frente deltaica. A associação dos traços aqui estudados caracteriza um ambiente subaquoso, lamoso, relativamente calmo e raso podendo representar as icnofácies Mermia (lacustre) e Scoyenia (transicional).

Les carbonates de sources hydrothermales (ou Geothermal Spring Carbonate, GSC) sont des systèmes carbonatés qui se développent autour de sources dont les eaux ont circulé en profondeur et sont remontées le long de failles perméables. Leur développement est contrôlé en tout premier lieu par la nature des eaux souterraines auxquelles ils sont liés. La formation de ces carbonates dépend d’interactions complexes entre les processus hydrologiques, tectoniques et structuraux se produisant avant l’émergence. Par la suite, la sédimentation est régie par de nombreux processus résultant des variations hydrologiques et chimiques de l’eau ainsi que par l’activité biologique. Du fait des interactions complexes entre ces facteurs, la sédimentation est sensible à de faible variations environnementales et il en résulte ainsi un grand nombre d’environnement de dépôts et de lithofacies.Le but de cette étude est d’améliorer les connaissances et les concepts fondamentaux propres au développement des carbonates de sources hydrothermales (GSC). Pour cela, elle s’appuie principalement sur l’examen des faciès que ce soit à petite échelle, comme l’observation des microstructures (microfabrics), ou à grande échelle, comme leur agencement en trois dimensions. De tels examens ont été effectués dans des sites hydrothermaux où ces carbonates se sont développés au cours du Quaternaire (région de Rapolano en Italie, bassin de Denizli en Turquie ou encore le Parc du Yellowstone dans le Wyoming, USA). / Geothermal spring carbonate (GSC) corresponds to a complex carbonate system formed around carbonate-rich springs fed by rising groundwaters along permeable fault zones. Their development is mainly controlled by the nature of springwaters emerging above water table. Therefore carbonate deposition is, in this setting, intimately related to complex interactions between hydrological, tectonic and structural processes occurring prior to water emergence. Moreover, carbonate sedimentation from springwater results from sedimentary processes controlled by complex interactions between hydrological, chemical characteristics and biological activity. Such processes are sensitive to slight environmental variations and thus lead to a large spectrum of lithofacies and ecosystems.The aim of this study is to improve knowledge and fundamental concepts regarding development of geothermal spring carbonates. For that purpose, lithofacies investigation, from microfabrics at micro-scale to 3-dimensional configuration at field-scale, is considered as an essential tool. Such investigations had been carried out in sites where Quaternary and actively forming GSCs were abundant (e.g. Rapolano region, Italy, Denizli Basin, Turkey and Yellowstone National Park, Wyoming, USA).

In South Central Cut Bank Sand Unit (SCCBSU) of Cut Bank field, primary production and waterflood projects have resulted in recovery of only 29 % of the original oil in place from heterogeneous, fluvial sandstone deposits. Using highresolution sequence stratigraphy and geostatistical analysis, I developed a geologic model that may improve the ultimate recovery of oil from this field. In this study, I assessed sequence stratigraphic concepts for continental settings and extended the techniques to analyze low-accommodation alluvial systems of the Cut Bank and Sunburst members of the lower Kootenai formation (Cretaceous) in Cut Bank field. Identification and delineation of five sequences and their bounding surfaces led to a better understanding of the reservoir distribution and variability. Recognition of stacking patterns allowed for the prediction of reservoir rock quality. Within each systems tract, the best quality reservoir rocks are strongly concentrated in the lowstand systems tract. Erosional events associated with falling baselevel resulted in stacked, communicated (multistory) reservoirs. The lowermost Cut Bank sandstone has the highest reservoir quality and is a braided stream parasequence. Average net-to-gross ratio value (0.6) is greater than in other reservoir intervals. Little additional stratigraphically untapped oil is expected in the lowermost Cut Bank sandstone. Over most of the SCCBSU, the Sunburst and the upper Cut Bank strata are valley-fill complexes with interfluves that may laterally compartmentalize reservoir sands. Basal Sunburst sand (Sunburst 1, average net-to-gross ratio ~0.3) has better reservoir quality than other Sunburst or upper Cut Bank sands, but its reservoir quality is significantly less than that of lower Cut Bank sand. Geostatistical analysis provided equiprobable representations of the heterogeneity of reservoirs. Simulated reservoir geometries resulted in an improved description of reservoir distribution and connectivity, as well as occurrences of flow barriers. The models resulting from this study can be used to improve reservoir management and well placement and to predict reservoir performance in Cut Bank field. The technical approaches and tools from this study can be used to improve descriptions of other oil and gas reservoirs in similar depositional systems.

No description available.

Ce manuscrit de thèse propose la première étude sédimentologique exhaustive de l’escarpement du Dur At Talah (150 km de long sur 120 m de hauteur). Ce dernier affleure dans la dépression d’Abu Tumayam, dans la partie méridionale du Bassin de Syrte (Libye). La Formation du Dur At Talah offre une séquence sédimentaire régressive (au 2nd ordre), allant de faciès marins peu profonds à des faciès fluviatiles, datée de l’Eocène supérieur. Les exceptionnelles conditions d'affleurement ont permis une analyse sédimentologique approfondie (lithofaciès, ichnofaciès, géométries et découpage séquentiel) conduisant à une caractérisation multiscalaire d'un système margino-littoral dominé par la dynamique tidale. Parmi les résultats saillants de cette étude figure l'identification de deux processus sédimentaires : la progradation signée par des structures clinoformes et l’accrétion latérale caractérisée par des stratifications hétérolithiques inclinées (IHS). Dès lors, plusieurs corps sédimentaires se distinguent sans ambiguïté tel que les barres d’embouchure hétérolithiques et les barres de méandres de chenaux tidaux. L'auscultation de ces grands corps sédimentaires permet alors d'en définir les critères de reconnaissance et le contexte séquentiel de mise en place, mais aussi d'en contraindre le potentiel réservoir. / This manuscript provides the first exhaustive sedimentological study of the Dur At Talah escarpment (≈120 m high and ≈150 km length). This latter is exposed in the Abu Tumayam Trough, in the southern Sirt Basin (Libya). The Dur At Talah Formation forms a 2nd order regressive sequence, from shallow marine to fluviatile deposits, dated as upper Eocene. This exceptional outcrop allows an extensive and detailed sedimentological analysis (lithofaciès, ichnofaciès, geometries and sequence stratigraphy) leading to a multi-scale characterization of nearshore to paralic environments dominated by tidal dynamic. Among outstanding results, two sedimentary processes have been recognized and characterized: the progradation is expressed by large-scale clinoform structures and the lateral accretion is characterized by inclined heterolithic stratifications (IHS). Several sedimentary bodies are, thus, unequivocally distinguishable such as heterolithic mouth-bars and tidal channel point-bars. Thorough analysis of these sedimentary bodies allows to define diagnostic criteria to recognize them. They can be replaced in a consistent stratigraphic framework explaining their architecture and their vertical evolution in order to be used as reservoir analog.