Despite the elevated heat flow known in the Western part of the South Slave Region (Northwest Territories, Canada), a continuous and equilibrium geothermal gradient was never measured in boreholes below the communities where geothermal energy could be developed. This paper aims to predict the geothermal gradient and assess the Earth’s natural heat flow below the communities of Fort Providence, Kakisa, Hay River, and Enterprise. Temperatures from drill-stem tests and bottom well logs were corrected for drilling disturbance and paleoclimate. The thermal conductivity and heat generation rate of the geological formations were determined from the literature and with new laboratory measurements. Original 1D models were developed to evaluate subsurface temperature through the sedimentary formations based on a thermostratigraphic assessment. The results indicate a geothermal gradient that varies from 44.1 ± 10.6 °C km−1 to 59.1 ± 14.9 °C km−1 and heat flow that varies from 105.5 mW m−2 to 160.2 mW m−2 below the communities. These estimates were in agreement with the equilibrium geothermal gradients measured in Cameron Hills, south of the four communities, and were used to verify our predictions. The highest geothermal gradient (59.1 ± 14.9 °C km−1) was estimated at Hay River, which, therefore, has the most favorable geological conditions for geothermal development.

Flooded mines constitute groundwater reservoirs that can be exploited with geothermal heat pump systems. Modelling such a reservoir is challenging because groundwater flow and heat transport equations need to be solved within the complex geometry of mine workings. To address this challenge, we developed a tridimensional numerical model to estimate the geothermal heat pump and underground energy storage potential, using the Con Mine near Yellowknife, Northwest Territories, Canada as an example. We used the finite element method to simulate the transient 3D temperature field within the water and in the rock mass. The shafts and tunnels of the mine are represented with 1D elements embedded in a tridimensional matrix. Hydraulic and thermal properties were evaluated at the mine site and in the laboratory with samples from outcrops and cores. The numerical model was calibrated to reproduce hydraulic head and temperature measured while pumping one of the shafts. Then, the long-term temperature of the water under different cases of geothermal heat pump operation was simulated for 25 years. The total energy delivered to buildings per year for a flow rate of 0.06 m3 s−1 was 953 MWh vs. 18,048 MWh when the pump depth was 0.3 vs 1 km. We also simulated heat production using solar thermal collectors to provide additional energy storage. The results suggest that it would be easier to increase energy production by augmenting the flow rate or by placing the pump at a greater depth than by adding solar collectors.

The Middle to Late Devonian was characterized by the widespread deposition of organic-rich mudstone units and successive biotic crises and anoxic events in the marine realm, the cause of which remains debated and requires constraints from associated marine conditions. This study provides an example of the marine nitrogen cycle throughout the late Eifelian to middle Frasnian anoxic pulses. We present new and previously published organic whole-rock N (δ15Nbulk) and carbon (δ13Corg) isotopic datasets from organic-rich mudstone units of the Horn River Group (Canol and Hare Indian Formations) and overlying Imperial Formation in the Central Mackenzie Valley, Northwest Territories, Canada. In the ConocoPhillips Mirror Lake N-20 core, δ13Corg ranges from −31.0 ‰ to −24.3 ‰ with δ15Nbulk from −3.8 ‰ to +1.9 ‰, whereas the Husky Little Bear N-09 core is characterized by δ13Corg from −31.0 ‰ to −27.2 ‰ and δ15Nbulk from −2.0 ‰ to +5.9 ‰. The N isotopic signatures near 0 ‰ and a lack of δ15Nbulk – δ13Corg relationship are characteristic of N2 fixation by primary producers. Regular oscillations in δ15Nbulk are interpreted as the product of episodic, mild oxygenation events. Together, our δ13Corg and δ15Nbulk results suggest that locally, N2 fixation was the dominant source of N for primary producers in the late Eifelian to middle Frasnian, despite fluctuations in δ13Corg and global marine paleoredox. These findings contribute to our understanding of the nitrogen speciation and bioavailability associated with anoxic events, biotic crises, and widespread organic carbon burial in the Eifelian to Frasnian oceans.

After the closure of an underground mine, tunnels commonly become flooded and can be potentially exploited for its geothermal resource. Developing new methods for quantifying the energy content of this reservoir with a complex geometry is important to assess the economic value of its heat resource. The objective of this paper is to provide a first-order assessment of the geothermal potential of an underground mine using the Con Mine near Yellowknife, Northwest Territories, Canada, as an example. Field data allowed the development of an improved analytical approach to evaluate the geothermal potential of the Con Mine based on a thermal power budget. The sources considered in the thermal power budget are the thermal inertia of the water in the mine and the surrounding host rock, and the water that infiltrates the mine from nearby lakes. Analytical calculations are based on the finite linear heat source equation, considering cooled or heated water in the mine tunnels as heat sources or sinks. The geometry of the underground mine is consequently simplified to a linear heat source of equivalent length and fixed radius. The Thiem equation is used to calculate the water seeping into the mine. Results obtained with this approach and considering the operation of a geothermal heat pump system indicate a total energy of 17,520 MWh y −1 and 8234 MWh y −1 that can be delivered to buildings for heating and cooling purposes, respectively. This new approach provides an improvement to the volumetric method commonly used to assess geothermal resources.

ABSTRACT Deep-water channel and levee deposits are common depositional elements on modern and ancient continental slopes. Unlike their channel counterparts, the spatial and temporal evolution of levee stratigraphy is much less well understood, in part because of the typically more recessive nature of levee deposits in the ancient sedimentary record, and sparse, widely spaced core control or seismic images of insufficient resolution in the modern. Moreover, it is generally inferred that levee development, at least in part, precedes the main phase of channel filling, the reasons for which remain largely unknown. In the Isaac Formation of the Windermere Supergroup (Neoproterozoic) of east-central British Columbia, Canada, well-exposed levee deposits are divided vertically into packages, each consisting of a sand-rich lower part overlain sharply by a mud-rich upper part. The lower part (3–10 m thick) consists mostly of medium- to thick-bedded, upper medium- to coarse-grained, lower-division turbidites intercalated with thin-bedded, fine-grained, upper-division turbidites. Along depositional strike away from channel-fill margins, the thickness of lower-division turbidites exhibit a distinctive thickening and then thinning over a few hundreds of meters that results in a similar thickening and thinning of the entire lower part of a package. The upper part (3–16 m thick) consists mostly of thin-bedded, fine-grained, upper-division turbidites intercalated with uncommon medium- to thick-bedded, medium-grained, lower-division turbidites. Significantly, the thickness of very thin- and thin-bedded turbidites in the upper part generally decreases stratigraphically upward whereas the thickness of intercalated medium- and thick-bedded turbidites changes little. The lateral and vertical changes in these deposits suggest that channelized flows were initially coarse grained and moderately well-sorted, causing them to exhibit negligible density stratification, and therefore high flow efficiency. We interpret that the velocity maximum occurred above the height of the incipient channel margins, thereby allowing the lower, coarse-grained, dense part of flows to easily overspill and deposit thick-bedded, coarse-grained turbidites in the lower part of each package. The sharp contact with the upper part of each package marks the point when relief from channel floor to levee crest exceeded the height of the velocity maximum in average throughgoing turbidity currents. Above this height, density of the flow decreased abruptly and consisted of significantly finer-grained sediment that overspilled to form the upper, finer-grained part of each package. Later the makeup of the sediment supply changed to a more polydispersed grain-size distribution, which caused the throughgoing currents to be more density stratified. This enhanced near-bed stratification and concentration effects, which in addition to intense interfacial mixing, resulted in rapid kinetic energy loss, and promoted deposition in the channel.

The characterization of porosity is an essential step in the evaluation of resource-bearing porous media. Here, we focus on the Devonian Hare Indian and Canol Formations, two potential unconventional mudstone reservoirs, in a core from the Horn River Group of the Central Mackenzie Valley, Northwest Territories, Canada. By combining bulk porosity, low-pressure N2 adsorption, and scanning electron microscopy (SEM) results with composition and lithofacies datasets, we assess the porosity in these successions to understand pore types, size, distribution, degree of connectivity, and controls and predictors of porosity. Mineral matrix pores (interparticle and intraparticle), organic matter pores, and lithofacies-dependant natural fractures are present. All pore types display limited connectivity in two dimensions. Mineralogy is the most significant control on porosity with trends in porosity present among lithofacies. No relationship is observed between porosity and total organic carbon (TOC), suggesting that mineral matrix pores, rather than organic matter pores, are dominant in this unit. We compare these results to other mudstone reservoirs in North America and show that the Bluefish Member (Hare Indian Formation) and the Canol Formation are characterized by comparable bulk porosity, lower N2 mesopore volume, and higher quartz content relative to the other units considered. In contrast, compared to the other unconventional reservoir examples, the Bell Creek Member of the Hare Indian Formation exhibits lower quartz and higher clay content, average bulk porosity, and lower N2 pore volume. The results collectively suggest that high quartz and low clay content are the best predictors of porosity in the Horn River Group. Natural fractures may serve as flow pathways to induced fractures; however, these units lack the network of interconnected organic matter pores that can be present in other successions.

The Hare Indian and Canol Formations, which are part of the Horn River Group in the Northwest Territories, Canada, primarily consist of organic-rich mudstones deposited during the Middle to Late Devonian. The formations were previously considered to represent marine basin fill accumulated in an oxygen-starved distal shelf setting, evidenced by the organic-rich character, pyrite content, and lack of macro-scale bioturbation. The depositional model, paleo‑oxygenation interpretations, and methods of organic carbon preservation presented in this study are in contrast to previous assumptions of the Horn River Group mudstones. Detailed petrographic, sedimentological, and ichnological analyses were carried out on thin sections taken from several cored Horn River Group intervals. These organic-rich mudstone units contain eight distinct microfacies, representing four main sedimentation processes acting on an interpreted distal shelf setting: (1) pelagic suspension settling, (2) plug-like sediment-gravity flows, (3) surge and surge-like low-density turbidity currents, and (4) debrites. Pelagic suspension-settling dominated in distal, quiet waters out of the reach of persistent storm influence. Debrites, plug-like flows, and low-density turbidite processes represent a continuum, wherein storm influence was the dominant driver in sediment delivery. Several morphologically distinct, microscopic biogenic-sedimentary structures (i.e. ichnofossils) have been identified throughout the mudstone intervals, indicative of sediment pore waters that were at least periodically partially oxygenated. Evaluation of total organic carbon content against bioturbation and microfacies interpretation suggest that persistent anoxia was not the dominant factor in organic carbon preservation, but rather a result of a combination of heightened sedimentation and burial rates and possible amplified rates of primary productivity. The results of this study may be applied to evaluations of other organic rich mudstones to enhance paleo-depositional interpretations.

Sandy sedimentary rocks rich in detrital matrix (>10% silt/clay) have long been recognized in the ancient sedimentary record, and nowhere more commonly than in deep-marine turbidite systems. Despite this, their depositional mechanisms remain poorly understood, in part because these rocks, which are enriched in fine-grained sediment, are often poorly exposed in outcrop or are confined to observation in core. Matrix-rich strata in the Neoproterozoic Windermere Supergroup, in contrast, are very well-exposed and show systematic changes in lithofacies over distances of several tens to a few hundreds of metres along-strike. Notably, these strata are observed in both basin floor and continental slope deposits, suggesting that their occurrence and systematic lithological arrangement is related to mechanistic, rather than palaeogeographic, controls. Specifically, the facies transect consists of structureless, clayey sandstone that transforms along-strike to a two-layer deposit with the development of an upper, planar-based, markedly more matrix-rich layer. Further along-strike, the basal clayey sandstone thins and eventually pinches out, leaving only the (upper) sandy claystone layer, which in turn thins along-strike and then pinches out. These systematic changes in lithology, but more specifically the distribution of clay, is interpreted to form a depositional continuum related to particle settling in a horizontally advecting, high concentration particle suspension formed along the margins of an avulsion-related high-energy turbulent suspension.

Despite a globally growing seismic and outcrop analogue data set, the detailed (centimetre to decametre) internal stratal make up of deep‐marine basin‐floor ‘channelized‐lobe’ strata remain poorly known. An ancient analogue for modern, mixed‐sediment, passive margin, deep‐marine basin‐floor fans is the well‐preserved Neoproterozoic Upper and Middle Kaza groups in the southern Canadian Cordillera. This succession is a few kilometres thick and comprises six sedimentary facies representing deposition from different kinds of sediment‐gravity flows. Representative lateral and vertical assemblages of one or more of these facies comprise six stratal elements, including: isolated scours, avulsion splays, feeder channels, distributary channels, terminal splays, and distal and off‐axis fine‐grained turbidite units. The internal characteristics of the various stratal elements do not differ from more distal to more proximal settings, but the relative abundance of the various stratal elements does. The difference in relative abundance of stratal elements in the kilometre‐scale stratigraphy of the Kaza Group results in a systematic upward change in architecture. The systematic arrangement of the stratal elements within the interpreted larger bodies, or lobes, and then lobes within the basin‐floor fan, suggests a hierarchical organization. In this article a hierarchy is proposed that is based on avulsion but, also importantly, the location of avulsion. The proposed avulsion‐based hierarchical scheme will be a useful tool to bridge the scalar gap between outcrop and seismic studies by providing a single stratigraphic framework and terminology for basin‐floor stratal elements.

Recent improvements in seismic resolution and more detailed outcrop mapping of basin-floor fans has shown that they are made up of a hierarchy of discrete building blocks. The most fundamental building block, made up of one or several event beds, is termed a stratal element. These elements stack to form lobes, which in turn stack to form lobe complexes and ultimately the fan. The arrangement of the building blocks on the fan is driven by channel avulsion, and the location of the avulsion defines the hierarchy.Basin-floor deposits of the Upper Kaza Group at Castle Creek comprise five stratal elements: scours fills, avulsion splays (interpreted to be genetically related with scours, and here combined into "avulsion complexes''), distributary channels, terminal splays, and fine-grained deposits. Using a Markov-chain statistical analysis the vertical stacking pattern of these elements was found to be non-random, which suggests an internal control or forcing on the system. Most notably, the results show that in spite of their thicker nature and high abundance in the studied section, sand-rich terminal splays are superimposed less frequently than expected in a random distribution of stratal elements. This reluctance of terminal splays to stack vertically suggests that it is not only deposition in the splay, but also the temporal stability of that deposition that drives upflow avulsions, and accordingly the observed stacking of the other associated stratal elements. This may be the result of the accumulated thickness of previous deposits forcing the system to episodically shift its depositional axis into bathymetrically lower areas. The consequence is that although the overall sedimentary pile contains abundant terminal splays with their characteristic high sandstone-to-mudstone ratio (similar to 75%), amalgamated terminal-splay deposits are thinner and the overall stratigraphic architecture more complex and heterogeneous than would otherwise be predicted in a random distribution of elements.

................................................................................................................................... I RÉSUMÉ ...................................................................................................................................... II DEDICATION............................................................................................................................. III ACKNOWLEDGEMENTS ....................................................................................................... IV TABLE OF CONTENTS ........................................................................................................... VI LIST OF FIGURES .................................................................................................................... XI LIST OF TABLES ................................................................................................................ XXVI CHAPTER 1: THESIS INTRODUCTION ............................................................................. 1 1.1 THESIS RATIONALE .......................................................................................................... 1 1.2 GEOLOGICAL SETTING AND REGIONAL STRATIGRAPHY .................................................... 3 1.2.1 Overview ..................................................................................................................................3 1.2.2 Stratigraphic framework and depositional interpretation of the WSG in the southern Canadian Cordillera .................................................................................................................................8 1.3 STUDY AREAS AND PREVIOUS WORK .............................................................................. 12 1.3.1 Previous work by the Windermere Consortium .....................................................................16 1.4 TERMINOLOGY ............................................................................................................... 19 1.5 THESIS OBJECTIVES AND STRUCTURE ............................................................................. 20 1.6 STATEMENT OF CONTRIBUTIONS .................................................................................... 22 CHAPTER 2: SEDIMENTARY FACIES IN THE MIDDLE AND UPPER KAZA

A common facies observed in deep‐water slope and especially basin‐floor rocks of the Neoproterozoic Windermere Supergroup (British Columbia, Canada) is structureless, coarse‐tail graded, medium‐grained to coarse‐grained sandstone with from 30% to >50% mud matrix content (i.e. matrix‐rich). Bed contacts are commonly sharp, flat and loaded. Matrix‐rich sandstone beds typically form laterally continuous units that are up to several metres thick and several tens to hundreds of metres wide, and commonly adjacent to units of comparatively matrix‐poor, scour‐based sandstone beds with large tabular mudstone and sandstone clasts. Matrix‐rich units are common in proximal basin‐floor (Upper Kaza Group) deposits, but occur also in more distal basin‐floor (Middle Kaza Group) and slope (Isaac Formation) deposits. Regardless of stratigraphic setting, matrix‐rich units typically are directly and abruptly overlain by architectural elements comprising matrix‐poor coarse sandstone (i.e. channels and splays). Despite a number of similarities with previously described matrix‐rich beds in the literature, for example slurry beds, linked debrites and co‐genetic turbidites, a number of important differences exist, including the stratal make‐up of individual beds (for example, the lack of a clean sandstone turbidite base) and their stratigraphic occurrence (present throughout base of slope and basin‐floor strata, but most common in proximal lobe deposits) and accordingly suggest a different mode of emplacement. The matrix‐rich, poorly sorted nature of the beds and the abundance and size of tabular clasts in laterally equivalent sandstones imply intense upstream scouring, most probably related to significant erosion by an energetic plane‐wall jet or within a submerged hydraulic jump. Rapid energy loss coupled with rapid charging of the flow with fine‐grained sediment probably changed the rheology of the flow and promoted deposition along the margins of the jet. Moreover, these distinctive matrix‐rich strata are interpreted to represent the energetic initiation of the local sedimentary system, most probably caused by a local upflow avulsion.

A common facies observed in deep-water slope and especially basin-floor rocks of the Neoproterozoic Windermere Supergroup (British Columbia, Canada) is structureless, coarse-tail graded, medium to coarse sandstone with 30 to up to >50% mud matrix content (i.e. matrix rich). Bed contacts are commonly sharp, flat and loaded. End-member facies include massive beds, beds in which matrix content increases abruptly in the upper part of bed, beds with traction structures, and beds with abundant mudstone clasts. Matrix-rich sandstone beds typically form laterally continuous bedsets that are up to several meters thick and several 10s to 100s meters wide, and commonly adjacent to units of comparatively matrix-poor, scour-based sandstone beds with large tabular sandstone clasts. Matrix-rich units are common in proximal basin-floor (Upper Kaza Group) deposits, but occur also in more distal basin-floor (Middle Kaza Group) and slope (Isaac Formation) deposits. Regardless of stratigraphic setting, units typically are directly and abruptly overlain by architectural elements comprising matrix-poor coarse-sandstone (i.e. channels and splays). Despite a number of similarities with previously described matrix-rich beds in the literature, for example slurry beds, linked debrites and co-genetic turbidites, a number of important differences exist, including the stratal make-up of individual beds and their stratigraphic occurrence, and accordingly suggest a different mode of emplacement. The matrixrich, poorly-sorted nature of the beds and the abundance and size of tabular clasts in laterally equivalent sandstones implies intense upstream scouring, most probably related to significant erosion by an energetic plane-wall jet or within a submerged hydraulic jump. Rapid energy loss coupled with rapid charging of the flow with fine-grained sediment likely changed the rheology of the flow and promoted deposition adjacent to the jet. Moreover, these distinctive matrix-rich

High-resolution aerial photography was captured covering a geological outcrop at Castle Creek, British Columbia, Canada. Here, for the purposes of hydrocarbon analog modeling, the outcrop was required to be accurately surveyed, so that key stratigraphic surfaces could be mapped in three dimensions. Because the outcrop strata were vertically orientated, these surfaces could be tracked over a wide area; however, to provide a true reconstruction of the geology, it was necessary to also model localized vertical cliffs providing a cross-section through the stratigraphy. Terrestrial lidar was utilized to cover these cliff sections which were poorly represented in the 2.5D aerial data. The integrated outcrop surface was textured with metric aerial and terrestrial imagery providing a photorealistic model that could be used for interpretation by geologists. This formed the basis for building a geocellular model of the geological volume, which was used to assist in the understanding of subsurface reservoirs where data are often limited.

The integration of 3D modelling techniques is often advantageous for obtaining the most complete and useful object coverage for many application areas. In this paper, terrestrial laser scanning and digital photogrammetry were combined for the purposes of modelling a geological outcrop at Castle Creek, British Columbia, Canada. The outcrop, covering approximately 2.5 km 2 , comprised a smooth, scoured surface where recent glacial retreat had left the underlying sedimentary rocks exposed. The outcrop was of geological interest as an analogue to existing hydrocarbon reservoirs, and detailed spatial data were required to be able to map stratigraphic surfaces in 3D over the extent of the exposure. Aerial photogrammetry was used to provide a 2.5D digital elevation model of the overall outcrop surface. However, because the sedimentary strata were vertically orientated, local vertical cliffs acted as cross-sections through the geology, and these were surveyed using a terrestrial laser scanner and calibrated digital camera. Digital elevation models (DEMs) created from both methods were registered and merged, with the fused model showing a higher fidelity to the true topographic surface than either input technique. The final model was texture mapped using both the aerial and terrestrial photographs, using a local triangle reassignment to ensure that the most suitable images were chosen for each facet. This photorealistic model formed the basis for digitising the geological surfaces in 3D and building up a full 3D geocellular volume using these surfaces as input constraints. Because of the high resolution and accuracy of the input datasets, and the efficacy of the merging method, it was possible to interpret and track subtle surface separations over the larger extents of the outcrop.

There are numerous examples of sheet sand deposits in the literature, but our knowledge is limited by restricted outcrop exposure or by the resolution of seismic data. Even in areas where exposure of deep-sea or basin-floor sediment is deemed good, such as the Tanqua Fan (Wickens and Bouma, 2000) or the Jackfork Formation (Coleman et al. 1994), work is often limited to correlation between widely spaced stratigraphic logs or to continuous exposures well below the size architectural elements of modern fans.

Introduction. Southern Ontario is underlain by an eroded Paleozoic bedrock surface dissected by numerous bedrock valleys. These valleys are infilled with variable thicknesses of Quaternary sediment that record paleoenvironmental change during the Late Quaternary and also host productive aquifers. The Dundas Valley of the Hamilton-Wentworth region forms a prominent west-east re-entrant in the Niagara Escarpment extending from Copetown in the west to Lake Ontario in the east. The modern valley is underlain by a buried bedrock valley estimated to be infilled with up to 180m of Quaternary sediment including glacial, lacustrine, and fluvial deposits. There are few exposures through these valley infill deposits and their subsurface characteristics and distribution are poorly understood.