Increased nitrogen (N) deposition onto boreal peatlands and forests is anticipated with further expansion of Alberta's oil sands industry and consequently, an increase in sources of nitrogen oxide emissions. Increased N deposition has the potential to affect peatland flora and alter N cycling patterns in peatlands, therefore it is imperative to investigate at what level of excess N deposition these effects take place. This thesis discusses results from the first two years of a five year N fertilization study being conducted at a peatland complex near the hamlet of Mariana Lake in northeastern Alberta, Canada aimed at quantifying the N "critical load" for these peatland ecosystems. At the study site there are forty-two experimental plots - half in an ombrotrophic bog, the other half in the poor fen - with varying N fertilization treatments ranging from 0 kg/ha/year to 25 kg/ha/year. To investigate nitrogen uptake by plants at the Mariana Lake study site, I measured nitrogen (N) and carbon (C) concentrations of Sphagnum capitulum tissue and vascular plant foliar tissue. For Sphagnum species, I also analyzed C:N ratios and capitulum N storage. To investigate potential growth response of the target Sphagnum species, measurements were taken for linear growth (the vertical elongation of the Sphagnum shoots), stem mass density (the weight of Sphagnum stems occupying a volume after capitula were removed), and ultimately, net primary production (the product of the prior two measurements). Capitulum mass density (biomass) was measured as well to investigate possible changes in Sphagnum capitulum growth. Also, during the height of the growing season (mid-July, 2011 and 2012), the plant communities in each treatment plot were sampled to provide "baseline" data necessary for documenting any shifts in plant distribution or community composition that may occur after N additions.

During the Cretaceous, the CO2 content of the global atmosphere increased in response to the volcanism associated with the disintegration of the former continents. This led to a considerable rise in global temperatures, leading to a significant rise in the global sea level and the landward movement of coastlines. Cretaceous marine strata transgressed directly on the underlying basement or much older sedimentary strata. Extreme environmental conditions in the Cretaceous involved a possibly more acidic and chemically destructive atmosphere than at present, which favoured widespread deep weathering at that time. The extensive Cretaceous palaeo-seaways played a vital role in transporting and depositing the huge volume of sediments generated during the weathering events, which included economically important placer deposits (e.g., gold, diamond and platinum). A direct consequence of the extreme Cretaceous global warmth was the widespread development of Cretaceous silcretes. Much of the world's heavy oil occurs in Cretaceous reservoir sands. The geological processes responsible for the widespread occurrence of the Cretaceous oil sands can also be traced back to the unique Cretaceous greenhouse climatic condition. The warm climatic conditions imply a higher heat flow regime in the subsurface, which contributed to the thermal maturation of the organic rich sediments that are closely associated with the Cretaceous transgressive sands. The oils were generated as conventional light oil, which later degraded into heavy oils, rather than thermally cracked oils from over-matured source rocks. Oils migrated into shallow warm reservoir sands that were favourable for microbial activities. All the studied Cretaceous oil sands show evidence of hopane degradation without the formation of 25-norhopanes despite diasterane degradation in some of the samples. This strongly implies that biodegradation in these studied Cretaceous oil sands occurred at shallow depths. Pyrite precipitated from an open system by means of microbial sulfate reduction as part of the biodegradation process.

In arid lands, a major contribution to water loss is by soil water evaporation. Desert sand dunes in arid regions are devoid of runoff and have high rates of infiltration. Rainwater is commonly stored within them because of the low permeability soils in the underlying desert pavement. In such cases, moisture is confined in the sand dune below a depth, termed as the “extinction depth”, where it is protected from evaporation during long dry periods. Moreover, desert sand dunes have sparse vegetation, which results in low transpiration losses from the stored water. The water accumulated below the extinction depth of the sand dunes can be utilized for various purposes such as in irrigation to support desert agriculture. In this study, field experiments were conducted in Western Saudi Arabia to monitor the soil moisture gradients and determine the diffusive extinction depth of dune sand. The dune sand was saturated with water and was exposed to natural conditions (evaporation and precipitation). The decline of the water level in the sand column was continuously recorded using transducers and sensors installed at different depths monitored the temporal variation of temperature and moisture content within the sand. The hydrological simulator HYDRUS-1D was used to construct the vertical profiles of soil water content and temperature and the results obtained from HYDRUS-1D were compared to the gradients monitored by the sensors.

Technological advances are required to reduce the environmental impact of the Canadian oil sands. Oxy-direct contact steam generation (DCSG) is one such way to move toward this goal, by producing steam for oil sands operations with a higher efficiency, lower fresh water consumption, and lower CO₂ emissions than traditional once-through steam generators. For DCSG, untreated process water, which may contain a variety of inorganics, is injected directly into the combustor to produce steam. The inorganic material that may deposit in the combustor as a result of that process water was studied for two applications of DCSG in the Canadian oil sands: (1) steam assisted gravity drainage (SAGD), and (2) mining, in order to inform refractory material selection for the combustor. For SAGD, free water knockout tank discharge was used as the process water and resulting deposits in the combustor were predicted to be high in silica and sodium oxide, and enriched with sodium sulfate as the potential operating temperature of the combustor was lowered. At the lowest combustor temperature studied (1075 °C), a low viscosity molten salt phase rich in sodium sulfate was also expected to form. It is recommended that the operating temperature of the combustor be as low as possible while still remaining above the formation temperature of this potentially corrosive salt phase, thus in the range of 1200-1250 °C in the regions of the wall where solids are expected to impact it. A number of candidate refractory materials were assessed through corrosion models and corrosion tests. Aluminosilicate based refractory materials should be avoided due to their potential reaction with the sodium oxide in the slag. This can result in formation of low density solid phases such as nepheline, which can damage the refractory material through volume expansion. Of the three refractories tested, mullite zirconia yielded the worst corrosion resistance, with dissolution of the binder phase and full penetration by sodium oxide. Chromia corundum yielded the greatest resistance to penetration of the materials tested, though some dissolution of the chromia in the slag was still evident. Further investigation into high chrome refractory materials is recommended for this application. For mining applications, mature fine tailings water (MFT) combined with an oil sands processing water (OPW) was used as the process water for injection. Due to the high liquidus of the resulting inorganic deposits, co-injection of a fluxant is recommended to reduce the liquidus and viscosity of the resulting slag solution, thereby maximizing the combustor efficiency by reducing the required operating temperature. Dolomite was identified as the optimal fluxant, at a concentration of 20 wt % CaMgO₂ in the fluxed slag. This mixture was found to have a viscosity of just under 25 Pa·s at 1300 °C, making this a good operating point for the DCSG combustor, as the slag should flow freely and not cause plugging. The corrosion resistance of several candidate refractory materials was assessed through modelling and laboratory scale testing for both the fluxed and non-fluxed slag. Similar to the results for SAGD, of the refractories tested, chromia corundum offered the greatest resistance to penetration, while mullite zirconia was most deeply penetrated by sodium oxide. Again, a chromia-containing refractory is recommended for further investigation for use in the DCSG combustor. Other candidate refractories investigated in the models that warrant testing are chromia spinel and magnesium aluminate spinel. For future work, further corrosion tests at multiple durations are recommended, as well as characterization of refractory samples from CanmetENERGY’s DCSG pilot plant and quantification of the effects of slag exposure on the mechanical strength of the refractory materials.

The Old Hickory mine is a world class placer titanium deposit located at the boundary of the Coastal Plain and the Piedmont in Virginia, astride the Sussex-Dinwiddie county line (77°34' W Long, 36°55'N Lat., Cherry Hill Quad). The Old Hickory deposit, discovered in 1987 by C. R. Berquist, was opened as a commercial mine in 1997, and is presently operated by Iluka Resources. Heavy minerals constitute an average of 8% of the sediment, but locally reach concentrations as rich as 60%. The ore minerals, in order of decreasing concentrations, are ilmenite, rutile, and zircon, which are believed to have been derived from weathering of Piedmont and Blue Ridge sources. After fluvial transport to the coast, the ore minerals were redistributed laterally along the coast by longshore currents, and ultimately concentrated by intense wave action, probably generated by large storms. The ores occur over an area of 8 km x 3 km, with ore minerals being found from the surface to up to depths of 12 meters, and appear to occur in at least two distinct ore horizons. This study examines the general ore mineralogy and differences in the mineralogy, grain sizes, secondary textures, and geochemistry of the ore minerals in the two distinct ore zones. Distinguishable differences between the two zones include a slightly coarser grain size, more angular grains of rutile, and a higher percentage of accessory minerals (epidote, garnet, etc) in the younger zone. Approximately 40% of all the ilmenite grains contain exsolution lamellae of hematite, a residual texture from the time of original ilmenite crystallization. Weathering of these ilmenite grains has preferentially dissolved out the hematite while preserving the original texture; thus the weathering increases the titanium content of the ore by removing some of the iron. The weathering also affects the distribution of minor elements such as aluminum, manganese, and chromium. At Old Hickory, the zircon population can be divided into two main types (thin, elongate rounded pink prisms, and short, thicker white to clear prisms) that may represent either multiple source regions or multiple generations of heavy mineral deposition. The variations in grain size, angularity, and rutile content are likely to be mappable and may prove useful in continuing stratigraphic studies, and in distinguishing separate ore zones. / Master of Science

Wetland reclamation efforts in the Athabasca Oil Sands Region seek to restore important ecosystem services that were lost consequent of disturbance from oil sands mining development in northern Alberta, Canada. Constructed on the Syncrude Canada Ltd. mineral surface lease, the Sandhill Watershed is the first attempt to engineer a landscape capable of supporting a self-sustaining wetland above a backfilled open-pit mine. In the chapters below, through characterization of porewater chemistry patterns, plant community structure, physical characteristics of soil and nutrient availability the overall performance of the wetland area (the Sandhill Wetland) is evaluated. Further, observations at the reclaimed site are compared to 12 reference wetlands (10 fens and 2 marshes) to evaluate the type of wetland to which the Sandhill Wetland is most analogous. After six growing seasons, although water table position management has occurred annually, the Sandhill Wetland exhibits many attributes similar to those of the natural sites monitored. In terms of porewater chemistry, the dominant anions and cations present in near-surface water (bicarbonate, sulfate, chloride, sodium, calcium, and magnesium) have increased annually since the first growing season. If trends continue, the chemical conditions at the reclamation site could be analogous to saline fens in about 7-8 years based on projections for increasing sodium and chloride concentrations. The Sandhill Wetland currently exhibits porewater chemistry attributes most similar to saline fens and slightly brackish marshes. Total plant cover across the reclaimed wetland was quite high averaging 95% in the sixth growing season. Using multivariate approaches (NMDS), results show that plant community structure across high and intermediate water table position areas are most comparable to marshes, with Typha latifolia and Carex aquatilis exhibiting the highest cover. Across the periphery of the site, where water table position is several centimeters below the soil surface, plant communities are quite dissimilar from the reference sites and dominated by the grass Calamagrostis canadensis. While sodium-tolerant species are present at the site, albeit at low abundance, it is unclear whether long-term exposure to sodium-dominated porewaters currently present at the Sandhill Wetland will affect performance of wetland plants that established under low-sodium conditions. In terms of soil characteristics, clear differences were apparent, namely, for soil bulk density patterns. Bulk density observations across all areas at the Sandhill Wetland were higher than the reference sites and total soil carbon concentrations were also low. These observations were expected, and as the Sandhill Wetland matures, I predict annual production and (or) deposition of plant litter/ roots and increased biological activity will restore near-surface soil properties in the wetland area, thereby increasing TC concentrations and reducing soil compaction. For functional processes, using plant root simulator (PRS) probe ion exchange membranes, results demonstrate nutrient supply across the Sandhill Wetland was most similar to the moderate-rich and saline fens except for sulfur supply, which was considerably elevated. Based on PRS probe and porewater observations, the Sandhill Wetland is not a eutrophic system in the sixth growing season, and supply for most nutrients are within the ranges of natural systems. However, effects from local atmospheric nitrogen deposition (reported up to 12 kg N ha-1 yr-1) could alter structure and function over subsequent growing seasons. Currently, ecosystem health and functionality of the belowground environment appears to be adequately restored at the reclamation site. Lastly, as no officially recognized protocols exist for evaluating performance of recently reclaimed wetlands constructed above open-pit mines, using the Sandhill Wetland as a test site I propose a framework for evaluating reclamation site performance. Although the proposed evaluation protocol does not rely on multivariate techniques, the performance evaluation results support the previous findings (that were based on multivariate analysis) that a marsh-like analogue is the most realistic reclamation outcome for the reclaimed Sandhill Wetland. While the reclamation has been highly successful in terms of creating a wetland that has persisted, future monitoring of water chemistry and plant community structure should continue at the Sandhill Wetland, to capture important successional changes that may occur as the site matures.

Peatlands comprise of approximately half of the Athabasca oil sands region, many of which overlay some of the world’s largest bitumen deposits where surface mining for this resource has permanently altered the landscape. By law, companies must reclaim disturbed landscapes into functioning ecosystems including integrated upland-wetland systems with the objective of forming sustainable peat-forming wetlands. This thesis presents six years (2013 – 2018) of water balance and associated salinity data from one of the two existing constructed upland-wetland systems, the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland built on soft tailings to evaluate the hydrological and hydrochemical performance and its potential to be self-sustaining. Following a considerable decrease in hydrological management, the dominant water balance components changed from primarily horizontal (inflow and outflow) to vertical fluxes (precipitation and evapotranspiration) which increased inundation, encouraged salt accumulation and changed plant communities. Results suggest that current conditions are not favourable for fen-peatland development as marsh-like conditions have developed, limiting water conserving functions and the ability to persist long-term in a changing climate. In terms of winter processes, topography currently controls snow accumulation, redistribution and melt at SFW while the role of vegetation in these processes is expected to increase as it continues to develop. Runoff ratios of snowmelt from hillslopes were drastically different than those previously reported for reclaimed peatland watersheds highlighting the influence of different soil materials used during construction. Under various climate change scenarios of a warmer and wetter climate, results from the Cold Regions Hydrological Model indicate that the influence of winter processes will decrease, potentially putting reclaimed systems at greater risk of moisture stress. Substantial hydrochemical changes have occurred as salinity was relatively low at the study onset as high volumes of inflow and outflow prevented ion accumulation. Over time, salinity continued to increase year-over-year throughout SFW from 2013 to 2018 in the wetland and margin areas. This increase in site-wide salinity was attributed to the shift in dominant water balance fluxes, changes in water table position and increased mixing of SFW waters with deeper saline groundwater that underlies the system. Based on its current conditions, it is unlikely that SFW will support peat-forming vegetation. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. / Thesis / Doctor of Philosophy (PhD) / A better understanding of the hydrological functioning of reconstructed peatlands in the Athabasca oil sands region is required as it is a novel approach in this region and there is potential for thousands of hectares of land that will require this reclamation in the future. Due to their recent establishment potential trajectories of constructed peatlands have yet to be fully analyzed as only recently has sufficient data been collected to evaluate the hydrological and hydrochemical functioning and provide insight on its overall success. While design strategies may seem sound, these constructed systems are completely human-made and it is unclear how they will develop and function in a highly disturbed landscape. Thesis results suggest that current conditions are not favourable to sustain a peatland as marsh-like conditions have developed which will limit its ability to persist long-term in a dry and changing climate. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Due to the many challenges associated with reclamation in this region, lessons learned from this pilot project will help guide future peatland construction.

As oil production increases in Alberta’s Athabasca Oil Sands Region (AOSR), optimization of tailings management processes will be integral to the successful reclamation of tailings-based environments. Syncrude Canada Ltd. has established an innovative dry-storage method for their wastes known as composite tailings (CT) that supports mine closure objectives by providing a base for terrestrial reclamation landscapes. Syncrude’s Sandhill Reclamation Fen is the first instrumented research wetland of its kind to be developed in the AOSR and it overlays a sand-capped composite tailings deposit in a retired open-pit mine site. This stratified sulfur-rich environment is highly anthropogenically altered and consists of three distinct zones: a constructed wetland, a 10m layer of sand, and 40m of CT. As oil sands tailings systems are becoming globally significant sulfur reservoirs due to their size, sulfur content, and diverse microbial communities, understanding the mechanisms behind H2S generation in novel tailings structures will help inform our understanding of sulfur-rich environments. This study is the first to characterize the sulfur biogeochemistry in each zone of the Sandhill Reclamation Fen deposit in an effort to establish the potential for microbial sulfur cycling and explore the mechanisms controlling H2S generation. Porewater ΣH2S(aq) was detected at all depths, increasing with depth from the surface of the wetland (<1.1 μM) and peaking in the sand cap (549 μM). Across all sampling trips, ΣH2S(aq) concentrations were consistently highest in the sand cap, with sampling-associated H2S gas concentrations in the wells reaching 104-180 ppm. Abundance of dissolved sulfate (0.14-6.97 mM) did not correlate to the distribution of ΣH2S, and dissolved organic carbon (21.47-127.72 mg/L) only positively correlated with the observed maxima of ΣH2S in the sand-cap. Identical sodium and chloride distributions in the sand and CT supported the model of upward migration of CT-derived porewater and fines into the sand cap. Functional metabolic enrichments established the ability of endemic microbial communities from all depths of the deposit to oxidize and reduce sulfur. Experimental microcosms demonstrated 1) the dependence of ΣH2S generation on the presence of fine particles; 2) stimulation of endemic microbial sulfur reduction through amendment with labile carbon and 3) increased generation of ΣH2S in the presence of thiosulfate over sulfate. Field and experimental results indicated that the bioaccessibility of recalcitrant organic carbon in the deposit likely controls rates of ΣH2S generation at depth. While the mechanisms relating CT-derived fines to ΣH2S in the sand cap are still unconstrained, the sand layer is clearly a bioreactive mixing-zone supporting optimal conditions for ΣH2S accumulation. These findings inform our understanding of biogeochemical sulfur cycling in novel oil sands reclamation deposits and will advise on-going optimization of tailings-based landscape management practices. / Thesis / Master of Science (MSc)

In this study, phospholipid fatty acids (PLFA) and carbon isotopes were used to characterize the response of in situ microbial communities to a pilot-scale wetland reclamation project in the Alberta oil sands, and to investigate their role in carbon cycling at the reclamation site. The Sandhill Fen reclamation project in the Athabasca oil sands region (Fort McMurray, Alberta, Canada) has created an artificial freshwater fen typical of the boreal forest region in which the oil sands occur. At this site, composite tailings (CT) residue was overlain with a thick sand cap and a freshwater fen constructed on top. Biomass in the peat material of the fen was comparable to that found in natural fens, and a comparison of PLFA profiles in peat, CT from a nearby site, and undisturbed wetlands in the area showed that microbial communities in Sandhill fen were more similar to those in the CT than those in undisturbed wetlands. Bacteria dominated the biomass, including a small percentage of sulphate reducing bacteria that are of particular interest in the reclamation project. Fungi and other eukaryotes were also present. Analyses of radiocarbon in total organic carbon (TOC) and residue from solvent extraction suggest that there was petroleum present in the peat layer of the fen. A small amount of young carbon from the fen surface has been transported into the CT layer in the form of dissolved organic carbon. Radiocarbon also showed that microbes preferentially metabolized more modern carbon within the carbon sources available to them. Biomass was more related to the age of carbon in the samples than to the TOC concentration, with younger carbon in the peat associated with higher PLFA concentration. / Thesis / Master of Science (MSc)

No / The paper presents patterns and mechanisms of light non-aqueous phase liquid (LNAPL) migration in an unsaturated/saturated sand, based on a detailed experimental investigation using a fully instrumented two-dimensional model with dimensions of 120 x 120 x 10 cm. Suction head and degree of saturation were monitored simultaneously using tensiometers and time domain reflectometry (TDR) transducers respectively. LNAPL spills into the unsaturated zone were simulated to investigate the influence of new variables of practical importance, including the spill area, volume of spill and fluctuations of groundwater table, on the patterns of LNAPL migration. The patterns are explained in terms of the relationship between matric suction and degree of saturation. Fluctuations of water level are found to have a major influence on the distribution of LNAPLs in the unsaturated/saturated sand for large volumes of LNAPL spill. Measurements of degree of saturation of water at different levels are used to explain the LNAPL migration. It was found that water suction head was not affected by migrating LNAPL if the degree of saturation of water was above the residual saturation. Results of LNAPL suction head were found to be consistent with the migration patterns. Additionally, the average suction head difference between different levels indicated accurately the direction of LNAPL migration, which was in good agreement with the patterns observed using electronic imaging.