A Deep Geologic Repository is proposed for a site on the eastern margin of the Michigan Basin at a depth of 680 metres in the Cobourg Formation. A study of the paleo-hydrogeolgical conditions for the area was conducted using numerical simulation of the distribution of natural tracers and the observed hydraulic head. To conduct the study, simulations of the groundwater flow systems were developed for hydraulic head generated from glacial loading cycles to study its effects on advective solute transport. The hydro-mechanical loading during the glacial cycles is assessed using numerical analysis of coupled stress and porewater pressure. The effect of density-dependent flow was assessed in a second study to estimate the degree of penetration of glacially-derived water driven into the basin during periods of glacial loading. Numerical simulations were used to explore the potential freshwater invasion pathways under a variety of conditions. Finally, profiles of 18O and 2H measured in porewater were combined with our understanding of the paleo-hydrogeological conditions derived from the studies above to test the hypothesis that solute transport was diffusion-dominated in this setting. A series of pure diffusion and advection-diffusion models were developed and the results were compared with profiles of natural water isotopes obtained from the study area. The results of the hydro-mechanical study of glacial impact show the development of significant underpressure during the interstadial periods, especially in the lowest permeability formations. The results also show that the formations have not reached hydrostatic conditions at the present time. These results were verified by comparison to measured environmental heads obtained from the study site. The density-dependent modeling showed that freshwater is capable of reaching the location of the study site through several permeable features. The transport simulations showed that the evolution time starting from a uniform initial condition, and using boundary conditions that are defined by freshwater invasion at several depths agrees with the hydro-geological history of this part of the Basin. The results also show the importance of advection on solute transport from the upper and lower boundaries even in rock of extremely low permeability. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2014-05-30 10:18:01.286

This thesis presents the findings of a combined geomorphological, sedimentological and geochronological investigation into the glacial history of the Clearwater Basin, Mid Canterbury, New Zealand. The study demonstrates that a thick wedge of glacial and paraglacial sediments are preserved in the valley. These are >100m thick and preserve evidence of at least 3 glacial phases (>180ka). The study presents a new and detailed geomorphology map for the Clearwater valley and adjacent areas and has added 17 new recessional positions to the local glacial record. Surface Exposure Dating (SED) has been used to directly date the moraines of the Clearwater Basin providing the first detailed chronology for glacial moraine in this area. In total 31 cosmogenic ages from 9 separate moraines are presented. The results demonstrate that the LGM advance is the Trinity moraine of Mabin (1980) and not the Hakatere moraine as previously assumed and that the LGM was achieved at or about 23ka. The Clearwater glacier receded up valley between 23 and 13ka with some indication of accelerated retreat after c.16ka. The correlation to the adjacent Lake Heron Valley is also revised.

Ecologically, the hyporheic zone (HZ) performs numerous roles within stream ecosystems (e.g. habitat, refugia from floods and droughts, nutrient cycling, pollution attenuation) with the dominant control on these various roles sediment composition. Recently, the body of literature on the role of sediment in the HZ has grown, though these studies rarely extend beyond the reach scale with little regional scale research undertaken in England and Wales. In this thesis, meio- and macrofaunal hyporheic assemblages at two depths (20cm and 50cm) across four geological regions (chalk – fine sediment, sandstone - fine to medium sediment and limestone – coarse sediment) two seasons (summer (n = 396) and winter (n = 192)) are described. The influence of recent glaciations (Devensian) on the distribution of stygobite fauna (summer (n = 192) and winter (n = 98)) is also considered. A reach scale experimental manipulation of sediment composition in the HZ of a highly dynamic, species rich and diverse study site (limestone) was also undertaken. I found the influence of glaciation on stygobite fauna still apparent in the two limestone areas with macrofaunal sized stygobite species rare or absent in both limestone areas. Meiofaunal sized stygobite fauna Antrobathynella stammeri (Crustacea: Syncarida) were recorded from the glaciated limestone site. These results suggest large stygobite fauna are rare or absent in the limestone areas of Northern England with meiofaunal stygobites possibly surviving in sub-glacial refugia. Stygobite fauna were abundant in southern England with alternative migratory routes north discussed (e.g. River Severn catchment and chalk aquifers). Geological regions had characteristic fauna with species richness and abundance of meio- and macrofauna high in the HZ of both limestone areas. Conversely, species richness and abundance was low in the chalk and sandstone HZ. The chalk HZ had a high abundance of macrofaunal sized Crustacea (Gammarus pulex) and low abundance of meiofaunal sized Crustacea (Copepoda). This suggested mechanical properties (burrowing) rather than morphology (body size and shape) was important in fine sediments, whereas in the limestone HZ morphology rather than mechanical properties was important. In the experimental study results were more intuitive with meiofauna abundant across all sediment treatments (fine, mixed, coarse and natural) with macrofauna abundant in sediment treatments containing a high proportion of coarse material. These results suggest Copepoda assume a greater role in ecological processes in fine sediment patches within a dynamic HZ, whereas when fine sediment dominates a system (e.g. chalk HZ) then the role of Copepoda is reduced. One implication could be the use of Copepoda as indicators of colmation and hydrologic exchange in the assessment of ecosystem health and give an indication of the refugial capacity of the HZ from projected high and low flow events in light of UK climate change forecasts.

The Carboniferous-Permian Grant Group of the Canning Basin, Western Australia, was deposited during the Late Palaeozoic Ice Age. This study utilises extensive seismic and well data to improve understanding of the controls on depositional style and architecture of the Grant Group. The study is based on 12 2D seismic surveys acquired between 1981 and 1990 on the Crossland Platform, Barbwire Terrace and Fitzroy Trough, and a newly acquired 3D seismic data on the Lennard Shelf, integrated with data from 66 exploration/appraisal wells. Particular focus has been on the structural evolution of the Canning Basin and its influence on Grant group deposition, the complex morphology of the Base Grant unconformity, and recognition of evidence for glacial environments from seismic and well data. Previous workers subdivided the Grant Group into the lower Reeves Formation and upper Grant Group. In this study the Reeves Formation is interpreted to be clearly a separate stratigraphic unit, defined as a syn-rift sequence restricted to the Fitzroy Trough. It records a growth of more than 1870 m toward the Fenton Fault. Movement along the Devonian-Carboniferous extensional faults is interpreted to have ceased prior to the deposition of the Grant Group. An angular unconformity observed at the base of the Reeves Formation is interpreted to be evidence for the middle Carboniferous Meda Transpressional Movement. Two large compressional anticlines underlying the Reeves Formation can be associated with a left-lateral bend in the Fenton Fault. The transpressional movement is interpreted to be characterised by a dominant dextral strike-slip movement. The event separates two major extensional phases of the Devonian-Carboniferous faults, the Devonian-Lower Carboniferous Pillara Extension and the Upper Carboniferous Point Moody Extension. The overlying Grant Group was deposited during a post-rift sag phase. Minor displacement of the Grant Group, associated with some faults, is the result of the later reactivation caused by the Triassic-Jurassic Transpressional Movement. The cessation of faulting prior to the Grant Group deposition supports the interpretation that the extensive diamictites observed throughout the Canning Basin are most-likely glacial in origin and not related to faulting. The base Grant Group Unconformity is observed to be a complex surface that develops as a result of a variety of processes, including faulting, salt dissolution and glacial erosion. Localised thickening of the older Worral Formation produces discrete topographic highs that dominate the Broome-Crossland Platform. They are interpreted to have formed initially as local depressions associated with subsurface dissolution of underlying Mallowa Salt. This resulted in deposition of a thickened Worral at these locations. Later partial dissolution of salt at the margins of these structures occurred prior to the Grant Group deposition, evident from reflector onlap onto these so called “Worral Sombreros” within the lower most part of the Grant Group. Later complete removal of salt, resulted in post depositional deformation of the Grant. The Grant Group can be divided into a number of formations, that have been correlated and mapped throughout the study area and their seismic facies interpreted to improve understanding of the depositional environments and evolution. The basal Betty Formation (≈80-500 m) consists predominantly of sandstone with thick intervals of diamictite and conglomerate and minor mudstone. Seismic interpretation in this study, together with integrated well analysis, supports previous studies that suggest it was deposited during repeated cycles of glacial advance and retreat. At least four cycles can be defined from this study, based on recognition of major erosional surfaces on the Lennard Shelf. The Winifred Formation (≈25-110 m) is mudstone dominated interval with minor sandstones, deposited during a major deglaciation. The Carolyn Formation (≈60-450 m) consists of massive and cross-bedded sandstones with thin intervals of mudstone. This study has recognised for the first time two probable glacial intervals restricted to the Lennard Shelf and Fitzroy Trough during deposition of Carolyn Formation. Detailed mapping has identified NW-SE to N-S oriented channels and palaeo-valleys systems, interpreted based on their character, to be formed sub-glacially by melt water. This extends the glacial influence in the basin to the end of the Grant group and these results provide valuable data on the influence of structural evolution and ice sheet dynamic and distribution within the Canning Basin. New information on the depositional architecture of the Grant Group also improves understanding of the potential for reservoir development with a section that has proven hydrocarbon potential.

No description available.

<p>Sulphur Creek, which occupies a basin to the north and west of Ancaster, Ontario, is fed by approximately 100 springs. This is the first detailed investigation of these springs. The results of this study are presented and a number of interesting conclusions have been drawn from them.Several directions for further research are also indicated.</p> <p> Physical analysis of the springs has revealed that they are on a planar, lacustrine blue clay aquiclude, which was formed as a result of meltwater ponding against an ice lobe, during the late Wisconsin glaciation. The meltwater lake covered most of the Sulphur Creek Basin, as indicated by the fact that blue clay was found all along the Creek's course. However, further research is required to determine the exact extent of this proglacial lake. </p> <p> A preliminary study of six springs was also undertaken in hope of determining the residence time of the groundwaters feeding the springs. It was found that there are significant short term trends in spring temperature, solute abundancies and 180 composition with season, suggesting that the residence times are surprisingly short. Also, the trends in the above variables suggest that groundwater residence time tends to vary from spring to spring. However, there are contradictions in trend when different variables are compared, which again suggests that further research is warranted. </p> / Thesis / Bachelor of Science (BSc)

No description available.

No description available.

Le climat continental et froid de la Béringie lors de la glaciation du Wisconsinien a conduit à la formation d’une forme relique de pergélisol syngénétique nommé yedoma. Ces dépôts ont permis la préservation d’indicateurs environnementaux très diversifiés qui peuvent être employés pour reconstituer la dynamique climatique et écologique de la Béringie avant le dernier maximum glaciaire. À ce jour, peu d’études ont été réalisées au nord de la chaîne de montagnes Brooks (Alaska) et l’hétérogénéité écologique régionale de la Béringie Est lors de la glaciation du Wisonsinien reste mal définie. Ce mémoire porte sur une reconstitution paléoenvironnementale de plus de 39 ka du nord de l’Alaska réalisée à partir de sédiments provenant du Yedoma de la rivière Itkillik. Les objectifs sont (1) de reconstituer l’histoire de la végétation avec l’analyse pollinique; (2) de reconstituer les températures de juillet, le contraste de température saisonnier et l’ensoleillement de juillet avec la technique des analogues modernes et (3) de mettre les données biogéochimiques et glaciologiques du site en lien avec le climat reconstitué. L’étude montre que vers 35 ka BP (Interstade du Wisconsinien Moyen), des conditions climatiques semblables à l’actuel ont favorisé l’accumulation de tourbe riche en carbone organique. À partir de 29,7 ka BP, les températures de juillet reconstituées diminuent, alors que la continentalité du climat semble augmenter. Le contenu en glace des sédiments est plus alors plus faible et la pluie pollinique devient dominée par Poaceae, Artemisia et autres herbacés non graminoïdes. Ces indicateurs suggèrent des conditions environnementales plus xériques qu’aujourd’hui. Les anomalies isotopiques de 18O, 2H et l’excès de deutérium confirment un épisode d’avancée glaciaire (Wisconsinien Tardif). Après 17,9 ka BP (Tardiglaciaire), les températures de juillet et le contraste saisonnier augmentent. Les valeurs de contenu en carbone organique des sédiments sont plus élevées et la plus grande disponibilité en eau favorise l’établissement d’un couvert herbacé moderne dominé par les Cyperaceae. / The cold-arid climate associated with the Wisconsinan glaciation in Beringia has led to the formation of a relict form of syngenetic permafrost, termed yedoma. These deposits contain various environmental proxies that can be used to reconstruct the climatic and ecological dynamics across Beringia prior to the Last Glacial Maximum (LGM). To date, only a few studies have attempted to reconstruct LGM climate north of the Brooks Range and the regional ecological heterogeneity of eastern Beringia is still poorly understood. The present thesis focuses on paleoenvironmental reconstructions of northern Alaska spanning about 39 ka, based on sediments from the Itkillik river Yedoma. The objectives are (1) to reconstruct the regional vegetation history from pollen analysis; (2) to reconstruct the July temperatures, seasonal temperature contrast and July sunshine based on the modern analogue technique applied to pollen and (3) to link the biogeochemical and glaciological records to the reconstructed climate. The study shows that around 35 ka BP (Middle Wisconsinan), climate conditions were similar than modern and favored the accumulation of peat and organic carbon. From 29.7 ka BP, July temperature decreased as continentality increased. Ice content was low and the vegetation was dominated by Poaceae, Artemisia and other non-graminoid indicators of xeric environmental conditions. Isotopic anomalies of 18O, 2H and deuterium excess indicate a glacial advance (Late Wisconsinan). Improving climate and ecological conditions is recorded after 17.9 ka BP (Late Glacial). Overall, the results are more similar to reconstructions of other sites located in northern and interior Alaska than those from interior Yukon or western Beringia.

Dans le Supergroupe Ouest-Congolais du bassin du Niari-Nyanga (Afrique centrale), les marqueurs des Glaciations Globales Sturtienne et Marinoenne sont représentés par les formations des «Diamictite inférieure» et «Diamictite supérieure».Ce travail de thèse présente une étude à haute résolution du Cap Carbonate associé à la Diamictite supérieure (6 coupes dans le bassin et 2 coupes dans la zone externe de la Chaîne du Mayombe). Les études pétrographiques révèlent la préservation des structures sédimentaires primaires et permettent de définir six microfaciès (MF0 à MF5) caractéristiques des paléoenvironnements de types inter- à supratidaux ou subtidaux. Dans le Cap Carbonate étudié, les indices de Kübler montrent une évolution croissante depuis la diagenèse profonde dans le bassin jusqu'à l'épimétamorphisme dans la zone externe de la Chaîne du Mayombe. Le signal isotopique ([delta]13C et [delta]18O) des Cap Carbonate échantillonnés est généralement reproductible dans le synclinal comme dans la chaîne, avec les valeurs du [delta]13C montrant une excursion négative variant de -2.6 [pour mille] à -5.6 [pour mille]. Les valeurs de d18O oscillent entre -6 [pour mille] et -12 [pour mille]. Par ailleurs, la confrontation des données minéralogiques, chimiques et isotopiques indique une influence négligeable des transformations post-sédimentaires sur la signature isotopique du Cap Carbonate indiquant la préservation des valeurs du [delta]13C de l'océan néoprotérozoïque. Enfin, l'ensemble des données de cette thèse et les résultats préliminaires des « Projets GLANEC» replacés dans un contexte régional permettent de définir le Membre SCIa du synclinal du Niari-Nyanga comme un Cap Carbonate lié à la Glaciation Marinoenne. / Within West-Congolian Supergroup of Niari-Nyanga Basin (Central Africa), the markers of Sturtian and Marinoan Global Glaciations are documented by the so-called «Lower Diamictite» and «Upper Diamictite». This work is based on 6 and 2 lithological sections from the basin and the external zone of the Mayombe fold belt. It corresponds to a high-resolution study of the Cap Carbonate lying unconformably on the Upper Diamictite. Petrographic analyses show preservation of primary sedimentary structures and lead to define six microfacies (MF0 to MF5). These microfacies caracterize paleoenvironments such as inter- to supratidal or subtidal types. Kübler index values of the studied Cap Carbonate display an increasing evolution from East to West, ie from a deep diagenesis in the basin to an epimetamorphism in the Mayombe external zone. Stable isotope signature ([delta]13C, [delta]18O) of the various components of this Cap Carbonate is reproducible throughout the basin as in the Mayombe external zone, with [delta]13C values displaying a negative excursion, decreasing from -2.6 ? to -5.6 ?. [delta]18O values of these components vary between -6 ? and -12 ?. Moreover, comparison between mineralogic, chemical and isotopic data indicates that post-sedimentary transformations had a very negligible influence on the isotopic signature of the Cap Carbonate, indicating preservation of d13C values of the Neoproterozoic ocean. Finally, when they are compared with other regional studies, all data of the present work and the preliminary results of the GLANEC Projects lead to the conclusion that the SCIa Member of the Niari-Nyanga Basin must be considered as a Cap Carbonate related to the Marinoan Global Glaciation.