Our understanding of fine-grained sediment regarding the processes in which they are transported and deposited is rapidly evolving. However, developing a depositional model and characterizing the vertical variability within mud-dominated deposits has seldom been done. A 103m Upper Mancos Shale core retrieved from the San Juan Basin, New Mexico was analysed with detailed thin-bedded facies analysis to observe vertical variability in lithology, sedimentary structures, bioturbation intensity, and depositional processes. Lithological variation suggests there are 3 full sequences, 9 system tracts, and 92 parasequences. Facies observed revealed multiple facies successions indicating depositional processes including ignitive turbidite, storms (tempestite), wave enhanced sediment gravity flows (WESGFs), tidal, biogenic reworking, fluid mud, suspension settling, and general bedload transport. Relationships between lithology, bioturbation intensity, sedimentary structures and depositional processes were observed to be interrelated in that energetic processes (i.e., storms, ignitive turbidite) were associated with coarser deposits and low bioturbation intensity; whereas lower energy processes (i.e., biogenic reworking, suspension settling, WESGFs) were associated with finer deposits and relatively higher bioturbation intensities. Furthermore, lithological variability integrated with depositional models indicated temporal changes in environment of deposition across shelf. / Thesis / Master of Science (MSc)

[pt] Atrelado à densa ocupação dessas áreas, identifica-se que parte de suas feições naturalmente protetoras da linha de costa são recorrentemente suprimidas da paisagem, dando lugar a obras de engenharia rígidas que passam a ocupar o perfil dinâmico das praias. Com isso, em casos de eventos de tempestades, as praias tornam-se susceptíveis a ação das ondas, bem como a população que habita a beira mar. Nesse sentido, o presente trabalho tem como objetivo caracterizar sazonalmente o comportamento morfodinâmico e sedimentar do arco praial localizado entre o Leblon e Arpoador e sua suspectibilidade aos efeitos das ressacas, fornecendo subsídios para a gestão do litoral. Para a obtenção dos dados foram aquisitados 32 perfis topográficos de praia entre 2018-2021, com o método das balizas de Emery; análises nas areias das praias (granulometria e morfoscopia); análises morfoscópicas; cálculos do volume emerso dos sedimentos e levantamento de alertas de ressacas emitidos pela Marinha do Brasil e demais veículos midiáticos. As extremidades do arco praial (pontos LB01 e AR01) apresentaram maior variabilidade morfológica e na largura da praia variação da largura da praia.; o ponto LB02 (próximo ao canal de Jardim de Alah) apresenta-se como o mais susceptível às ondas de tempestades; e o ponto IP01 (localizado no meio do arco), é considerado o mais estável devido à presença de ilhas em sua frente. Os sedimentos emersos do arco praial exibiram uma sazonalidade marcada por acúmulo no verão e perda subsequente dos mesmos no inverno. O papel das ondas é essencial na dinâmica do arco praial, com incidência predomiante de Sudoeste (tempestade) e Sudeste (tempo bom), o que possibilita a formação de correntes de deriva litorânea importantes na distribuição Leste-Oeste rotacional de sedimentos no arco praial. Conclui-se que o arco praial apresenta certo equilibrio dinâmico, uma vez que os perfis topográficos mostram grande variabilidade de largura e tal dinâmica pode ser corroborada pela relação de ganha e perda do volume de sedimentos do arco. A areia média é predominante porém percebe-se uma distinta distribuição dos grãos no arco praial: observou areias médias a grossas na porção oeste (Leblon) e areias médias a finas na porção leste (Arpoador). A distribuição sedimentar se mostra diferente também em termos de grau de arredondamento (no pós-praia os grãos são subarredondados e na face de praia são subangulares), seleção do grão e maturidade. / [en] Linked to the dense occupation of these areas, it is identified that part of its features that naturally protect the coastline are recurrently suppressed from the landscape, giving way to rigid engineering works that begin to occupy the dynamic profile of the beaches. With that, in cases of storm events, the beaches become susceptible to wave action, as well as the population that inhabits the seaside. In this sense, the present work aims to seasonally characterize the morphodynamic and sedimentary behavior of the coast located between Leblon and Arpoador and its susceptibility to the effects of storm surges, providing subsidies for the management of the coast. To obtain the data, 32 topographic beach profiles were acquired between 2018- 2021, using the Emery method; beach sand analyzes (granulometry and morphoscopy); morphoscopic analysis; calculations of the emerged volume of sediments and survey of storm surge alerts issued by the Brazilian Navy and other media outlets. The ends of the beach (points LB01 and AR01) showed greater morphological variability and variation in beach width in beach width.; point LB02 (close to the Jardim de Alah channel) is the most susceptible to storm waves; and point IP01 (located in the middle of the arc), is considered the most stable due to the presence of islands in front of it. Emerged sediments from the coast exhibited a seasonality marked by accumulation in summer and subsequent loss in winter. The role of waves is essential in the dynamics of the beach arc, with predominant incidence from the Southwest (storm) and Southeast (clear weather), which enables the formation of longshore drift currents that are important in the rotational East-West distribution of sediments in the beach arc. It is concluded that the Leblon-Arpoador coast presents a certain dynamic balance, since the topographic profiles show great variability in width and such dynamics can be corroborated by the relationship between gain and loss in the volume of sediments in the arch. Medium sand is predominant, but a distinct distribution of grains can be seen in the coast: medium to coarse sand was observed in the western portion (Leblon) and medium to fine sand in the eastern portion (Arpoador). The sedimentary distribution is also different in terms of degree of roundness (in the backshore the grains are subrounded and in the beach face they are subangular), grain selection and maturity.

Deep-marine channels are conduits for turbidity currents that transport sediment from the continental shelf to the deep ocean floor. Along the way, some of the sediment suspended in the current is deposited within the channel whereas the rest of the sediment makes its way to deeper water to construct basin-floor lobes. Slope channel deposits provide information about past climates and other perturbations to Earth systems; the transfer of nutrients, pollutants, and organic carbon; and can be important subsurface reservoirs (hydrocarbon, groundwater, etc.). However, studying the processes associated with deep-marine channels is challenging and difficult to monitor directly. The Cretaceous Tres Pasos Formation in southern Chile is exposed in an extensive and well-documented outcrop belt where preserved slope channels and their sedimentary fill can be studied. Previous work has focused on these channels at a macroscopic scale (meters to kilometers) but very few studies have been conducted on the microscopic scale. For example, little is known about how the sedimentary texture, specifically grain size and sorting, of channel-fill sandstones vary across the width and along the length of a channel. Here, we quantify grain size and sorting by hand using petrographic analysis of 57 sandstone samples from eight channel-fill transects. Our results show that there are no systematic relationships of deep-water sandstone size and sorting within channel architectural transects (e.g., from axis to margin). We also show that there are no textural trends throughout the entire study area of the Figueroa unit (~25 km length of the slope system). We also find that these sandstones are poorly to very poorly sorted, which has implications to understanding the depositional processes. Finally, we also identify that these rocks should be classified as silty sandstones rather than sandstones according to Folk (1954). Based on our results we can predict that these flows were probably well fit to the channels as well as having similar velocities, concentrations, carrying capacity for grain size in suspension, etc. across multiple flows. We can also make predictions about these samples having a detrital vs. diagenetic matrix based on their volcanic lithic rich composition and looking at hybrid event beds (HEBs) to see if similar processes could be going on at this location. We hope that this human measured dataset can be used as a baseline and for the improvement of automative measuring processes that have started to develop. / Master of Science / Sediments that come from land get transported to the ocean by way of turbidity currents which travel through submarine channels bringing those sediments with them. Along the way, sediments will get deposited in the channel before the current reaches the ocean floor giving us channel-fill sandstones. The sediments that get deposited in these channels can provide us with information on things such as past climates; transfer of nutrients, pollutants, and organic carbon; and can be important subsurface reservoirs. Studying these channels directly in the ocean can be hard to do so we study outcrops which allow us to study sediments that have been buried, lithified, and uplifted onto land. This study looks at the Cretaceous Tres Pasos Formation in southern Chile where we have lots of exposure to these antient submarine channels. Lots of previous work in this area has focused on large scale dynamics (macroscale) but there has been very little study looking at these small-scale dynamics (microscale). For example, little is known about how sedimentary texture, grain size and sorting, of channel-fill sandstones might change across the width and along the length of a channel. In this study we measure the grain size and sorting by hand using petrographic analysis of 57 sandstone samples from eight channel-fill transects. Our results show no trends in deep-water sandstone size and sorting within different transects (e.g., from the middle to outside) or across the whole study area (~25 km). We also find that these sandstones are poorly to very poorly sorted and that the classification of these rocks according to Folk (1954) is silty sandstones rather than sandstones. Based on these results we can make predictions about the flow of turbidity currents in relation to submarine channels such as flows having similar velocities, concentrations, carrying capacity for grain size in suspension, etc. across multiple flows. We can also make predictions about where the matrix of these rocks might have originated based on the composition of the rocks and by looking at another type of flow, hybrid event beds (HEBs), to see if similar processes could be going on at this location. We hope that this human measured dataset can be used as a baseline and for the improvement of automative measuring processes that have started to develop.

This thesis presents stratigraphic, sedimentological and geochronological results from valley fill and glacial moraines of the Hope-Waiau Valleys in North Canterbury, New Zealand. The findings demonstrate that a substantial portion of the modern valley fill comprises in-situ sedimentary sequences that were deposited during the penultimate glaciation (OIS 6), the last interglacial (OIS 5) and during the mid-late last glacial cycle (OIS 3/2). The sediments survived at low elevations in the valley floor despite overriding by later glacial advances. Sedimentologically, the fill indicates deposition in an ice marginal zone and consists of paraglacial/distal-proglacial aggradation gravels and ice-proximal/marginal-subglacial sediments. Deposition during glacial advance phases was characterized by the sedimentation of outwash gravels and small push moraines while glacial retreat phases are dominated by glaciolacustrine deposits which are frequently interbedded with debris flow diamictons. The overall depositional arrangement indicates that glacial retreat from the lower valley portion occurred via large scale ice stagnation. Results from infra-red stimulated luminescence (IRSL) dating gives evidence for five large aggradation and degradation phases in the Hope-Waiau Valleys over the last 200 ka. Combined with surface exposure dating (SED) of moraines the geochronological results indicate that glacial advances during OIS 6 were substantially larger in both ice extent and ice volume than during OIS 4-2. The last glacial maximum (LGM) ice advance occurred prior to 20.5 ka and glacial retreat from extended ice positions began by ~18 ka BP. A late glacial re-advance (Lewis Pass advance) occurred at ~13 ka BP and is probably associated with a regional cooling event correlated to the Antarctic Cold Reversal (ACR). The findings from the Hope-Waiau Valleys were integrated into a model for glaciations in the Southern Alps which uses data from a snow mass balance model to analyse the sensitivity of glacial accumulation to temperature forcing. Model results indicate that in the central hyperhumid sector of the Southern Alps ice would expand rapidly with minor cooling (2-4℃) suggesting that full glaciation could be generated with little thermal forcing. Some Quaternary glacial advances in the Southern Alps may have been triggered by regional climate phenomena (e.g. changes in ENSO mode) rather than requiring a thermal trigger from the Northern Hemisphere.

La démarche d’intégration des hétérogénéités dans les modèles réservoirs en est à ses prémices dans le domaine du stockage géologique de CO2. C’est dans ce contexte que s’inscrivent ces travaux de thèse. Un protocole d’analyse depuis l’étude de terrain jusqu’aux simulations réservoirs a été établi. La caractérisation du Minjur Sandstone (formation Triasique d’Arabie Centrale) met en avant le caractère crucial de la connectivité des corps dans l’architecture du réservoir, notamment en liant génétiquement leur nature, leur connectivité et leur position dans la séquence de dépôt. S’appuyant sur la connaissance de cette formation, un modèle conceptuel est construit, puis reproduit stochastiquement par un algorithme permettant l’élaboration de modèles conditionnés par une histoire sédimentaire. Le protocole prévoit la création de 50 scénarios illustrant divers degrés de connectivité ; chaque scénario étant composé de deux modèles de même architecture mais à remplissage sédimentaire différent. Cette approche permet d’appréhender (a) l’impact de la connectivité et (b) des hétérogénéités sédimentaires sur les performances réservoirs. L’estimation de capacité par l’approche statique des volumes disponibles estime une capacité moyenne d’environ 13Mt (aquifère semi-infini de 25 km par 25 km et 60m d’épaisseur à 1000 m de profondeur). Les hétérogénéités internes (sédiments argileux appelés oxbow lakes) entraînent une différence de capacité de 30%. Les simulations dynamiques confirment ces résultats et révèle une variabilité de capacité de 23% liée la connectivité des corps. De plus les hétérogénéités réduisent la migration verticale du gaz ce qui peut augmenter l’intégrité du stockage. / In the CO2 storage context, heterogeneity has only been rarely considered in reservoir models to date. To address this key issue, the project aims at developing a workflow that manages the heterogeneity from the field observations up to the reservoir simulation. The characterisation of the Minjur Sandstone (a Triassic formation from Central Saudi Arabia) shows the crucial role of connectivity in the reservoir architecture, and the genetic link between the nature, location and connectivity of the sedimentary bodies in the sequence. Stemming from this study, a conceptual model was established and stochastically reproduced through an algorithm simulating models conditioned to a sedimentary history. Fifty scenarios were simulated, representing various connectivity degrees. Each of these scenarios is composed of two models, identical by their architecture but different in their internal sedimentary fill. This approach allows the study of the impact of the (a) reservoir bodies’ connectivity and (b) their internal sedimentary heterogeneity on the reservoir’s performances. The capacity estimates using a static calculation based on the available pore volumes reveals a mean capacity of 13 Mt (for a 25 x 25 km x 60 m semi finite aquifer at 1000m deep). The sedimentary heterogeneity (shaly deposits called oxbow lakes) is responsible for a 30% difference of capacity. The flow simulations confirm these results and show that the connectivity of the reservoir bodies creates a 23% capacity variation. Moreover, the heterogeneities tend to reduce the amount of CO2 able to reach the uppermost reservoir which may enhance the storage integrity.

M.Sc. (Geology) / Please refer to full text to view abstract

M.Sc. (Geology) / Please refer to full text to view abstract

Using an integrated dataset comprising outcrop, core, GPR and LiDAR data, this study targets a high-quality outcrop "window" of the upper Cretaceous Blackhawk Formation in the eastern Wasatch Plateau in central Utah, spanning a fairly large spatial (~30 km2 area comprising eight contiguous, and vertical cliff faces) and temporal (~4 my) range. This research provides field-validation and -calibration of a wider range of fluvial heterogeneity: 1) large-scale heterogeneity (10’s of m vertically and 100’s of m laterally), 2) intermediate-scale heterogeneity (1’s of m vertically and 10’s of m laterally), and 3) small-scale heterogeneity (10’s of cm vertically and 1’s of m laterally). These sandbody- to facies-scale heterogeneities generate potential for stratigraphic compartmentalization for analogous fluvial reservoirs and prospects. Moreover, these results specifically constitute an outcrop analog to the producing tight-gas fluvial reservoirs of the adjacent hydrocarbon-prolific Uinta and Piceance Basins of Utah and Colorado, including the giant Jonah Field of Wyoming. 3D virtual outcrop model generated from LiDAR-integration has helped in avulsion-scale (~1's-10's kyr) to basin-fill scale (~100's kyr-1's myr) fluvial sandbody organization analysis down to channel-storey level. This high-resolution analysis has brought several intriguing insights. single-storey sandbodies are preferentially attendant to clustering organization, whereas multi-lateral sandbodies (i.e. channel-belt) show compensational-prone behavior. Sandbody organization is broadly compensational for the lower Blackhawk Formation, where the floodplain facies diversity is the highest. In contrast, floodplain diversity decreases stratigraphically upward such that the upper Blackhawk Formation shows the least heterogeneous floodplain with clustering-prone sandbody organization. In the quest of differentiating autogenic from allogenic signal in dynamic systems where their interplay is complexly intertwined, this study presents two incised-valley examples, where resultant fluvial organization has been interpreted, contrary to conventional wisdom, to be preferentially modulated by a dominant controlling mechanism of autogenic forcing. In filling these incised valley deposits, each of which is up to ~15-20 m thick, the dominating behavior of substrate coal compaction as an autogenic mechanism supplanted allogenic forcing (i.e. sea-level fluctuation).

The town of Grand Isle, Louisiana, and its rich geographic history, can offer insight into the early history of the State of Louisiana and the establishment of the United States as a country, as well as the study of the formation of barrier islands and methods of land use with such areas. The following thesis presents a geographic, as well as a historical, analysis of Grand Isle’s history. It attempts to answer the following questions: What is the shape, form, and origin of the physical landscape of Grand Isle? How have humans interacted with the land and surrounding areas of Grand Isle? And what impacts, if any, have these interactions had on the island and its landscape? These questions include research into both the built environment and the natural environment.

En tant qu'un des plus grands bassins sédimentaires du bloc de Chine du Sud, le bassin de Nanpanjiang a attiré une grande attention de la communauté géologique depuis de longtemps. Après plusieurs années de recherche, il reste encore de grand débats sur i) la provenance du bassin, ii) l'âge du changement de régime extension à compression, iii) le type de bassin et son contexte géodynamique. Dans cette thèse, nous avons conduit une étude pluri-disciplinaire incluant l'analyse des faciès sédimentaires et leur distribution géographique, paléocourants, spectres des minéraux lourds et leur geochimie, la géochronologie U-Pb sur zircon et baddeléyite, et le magnétisme des roches pour reconstrurier l'evolution de ce bassin. Les résultats indiquent un trois-étapes évolution. i) durant la période du Permien supérieur au début du Trias, la diabase mise en place 269Ma annonce l'ouverture du bassin, l'environnement sédimentaire est devenu plus profond. ii) durant la période du stade tardif du Trias inférieur (~ 245 Ma) au Trias moyen, à cause des influences de l'orogène Xuefengshan et de l'orogène d'Indochine situées à l'est et au sud du bassin, le bassin a évolué en bassin d'avant-pays. La diabase arrête sa mise en place durant cette période. Les analyses de détritus et de paléo-courants indiquent que durant cette période, les provenances de la partie est et de la partie sud du bassin étaient respectivement l'orogène Xuefengshan et l'orogène Indochinois. iii) la fin du Tirassique, la profondeur de l'environnement sédimentaire a fortement diminué, indiquant que le bassin a commencé à se rétrécir sous l'effet de la compression de l'orogène Xuefengshan et de l'orogène d'Indochine. / Ranks as the largest sedimentary basin in the South China during the Triassic, The Nanpanjiang basin attracts a large attention of the geology community for a long time. After many years study, there still exist several debates on i) the provenance of the sedimentary detritus, ii) the time of the change of the tectonic regime from extension to compression, iii) the type of the basin and its geodynamic background. In this thesis, a multidisciplinary study including analysis of sedimentary facies, paleo-current, frame work detritus mode, heavy mineral combinations and their geochemistry feature, rock magnetism and Zircon-baddeleyite isotopic dating on diabase was conducted to rebuild the evolution of the basin.The results show a three-stage evolution, i) during the Late Permian to the Early Triassic, the 269Ma diabase intruding into the basin announces the opening of the basin, the sedimentary environment became deeper. ii) During the late stage of the Early Triassic (~245 Ma) to the Middle Triassic, owing to the influences of the Xuefengshan orogen and the Indochina orogen which are located to the east and south of the basin, the basin evolved into a foreland basin. The diabase ceased emplacement in this period. The detritus and paleo-current analysis indicate that during this stage, the provenances of the East part and the South part of the basin were Xuefengshan Orogen and Indochina Orogen respectively. iii) During the Late Tirassic, the depth of the sedimentary environment decrease drasticly, indicating that the basin began to shrink owing to the compression of the Xuefengshan Orogen and the Indochina Orogen.