Earth and Environmental Sciences Undergraduate Honours Theses

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Open Access
Edge Influence on Tree Regeneration After Fire in the Acadian Forest Region
(2025-04) Elizabeth Faye Little
As climate change intensifies, fire regimes are shifting in regions historically considered low risk, such as Nova Scotia and New Brunswick. The 2023 wildfire season saw record breaking fires in both of these provinces, highlighting the need to understand post fire regeneration dynamics and creating an expansive study area. This study examined patterns of tree regeneration across fire edges in the Acadian Forest, a region characterized by a mix of temperate and boreal species. I hypothesized that regeneration would be higher near fire edges due to increased seed dispersal and light availability. To assess these patterns, data were collected at two major fire sites, one in Nova Scotia and one in New Brunswick, establishing six transects that spanned from 200 m into the burned area to 200 m into the interior forest. Sapling data, including species, height, and regeneration origin, were collected at various distances along each transect and analyzed using randomization tests. Key response variables included total sapling density, species diversity, and richness, as well as individual sapling species. Contrary to my hypotheses, results indicated minimal edge influence on regeneration, with sapling density generally greater further from the fire edge. Species-specific responses varied; Abies balsamea exhibited greater regeneration deeper into the forest, while Acer rubrum saplings were more abundant closer to the edge. Seed-origin saplings displayed inconsistent distribution patterns, while root and stump-origin saplings exhibited more localized regeneration trends. These findings suggest that fire-created edges in the Acadian Forest do not follow regeneration trends observed in other Canadian forest ecosystems. The study highlights the importance of species-specific and mechanism-specific analyses in post-fire recovery research. Understanding these dynamics is critical for refining forest management strategies and developing conservation practices tailored to the unique ecological conditions of the Acadian Forest. Keywords: Tree Regeneration, Forest Fire, Acadian Forest, Edge Influence, Fire Edges
Open Access
Bioaccumulation of Heavy Metals by Leach’s Storm-Petrels (Hydrobates leucorhous) in the North and South Atlantic Ocean during the Non-breeding Period
(2025-04) Catherine Potvin
Leach’s storm-petrels (Hydrobates leucorhous) have experienced a significant decline in Atlantic Canada and are currently listed as “Threatened” by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Many factors may underlie this decline, including exposure to heavy metals. While mercury (Hg) levels have been measured in blood and eggs of breeding storm-petrels, these short-term indicators have not been associated with impacts on hatching or fledging success. However, longer-term Hg intake and the extent of exposure to other heavy metals during the non-breeding period remain unknown. In this study, secondary feathers were assayed to assess variation in heavy metals concentration among five overwintering regions in the Atlantic Ocean. Using geolocation data, centroid locations for each overwintering region were calculated for February, when feathers are grown. Overwintering region was a significant predictor of Hg concentrations, whereas other heavy metal varied without a clear regional effect. Foraging indicators were also strong predictors of Hg concentrations, whereas colony of origin had no influence, likely due to high individual plasticity in non-breeding migration behavior. Hg concentrations were negatively correlated with δ¹⁵N values, emphasizing the role of diazotrophic organisms in reducing baseline nitrogen levels in oligotrophic ecosystems such as the mid-Atlantic, while sulfate-reducing bacteria simultaneously enhance methylmercury bioavailability. In contrast, Hg concentrations were significantly lower in more productive upwelling regions like the Benguela system, where rapid export to deep sediments through decaying phytoplankton biomass and sinking particles drive Hg biodilution. Given their extensive migration across the Atlantic Ocean, Leach’s storm-petrels serve as valuable bioindicators of heavy metal pollution. This study provides the first insight into exposure and bioaccumulation of heavy metals during the non-breeding period of Leach’s storm-petrels. My results can serve as a baseline for assessing migration-to-breeding carry-over effects on adult survival and fledgling survival to maturity in the Atlantic population, as these factors remain unexamined. Furthermore, combining these findings with sulfate-isotope analysis could help future studies to better understand Hg biogeochemistry and contaminant dynamics within Leach’s storm-petrel preys during the overwintering period. Keywords: Mercury biodilution effect; upwelling; oligotrophic region; sulfate reducing bacteria; diazotrophs; detoxification
Open Access
Analyzing Calcites With In-Situ LA-ICP-MS to Obtain an Age for the McArras Brook Formation
(2025-04) Ben Thompson
The McArras Brook Formation is located on the Northwest coast of Nova Scotia, Canada, consists of interlayered red-bed sedimentary rocks, and amygdaloidal basalt. This formation plays a part in Dalhousie University’s intermediate field school course each Summer, however other than this it has not been often studied. The formation has been placed stratigraphically in the early Devonian period, but no absolute (numerical) age is known, nor are there absolute ages known for surrounding units. The amygdaloidal basalts in the unit contain calcite, forming the amygdules, which has been dating using U-Pb techniques previously for both eruption/volcanism and tectonic events for basalt. The basalts in this unit have also been characterized previously in a Dalhousie project, and this project aims to continue work done on this unit. This project uses Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) to analyze over thirty isotopes in-situ on calcite samples taken from the McArras Brook basalt. Data acquired from analysis is used to image isotopic distribution on sampled locations, to create temperature maps of sampled locations, and ultimately to plot U and Pb ratios to obtain an absolute age for the unit. Keywords: Calcite dating; Carbonate dating; LA-ICP-MS; U-Pb geochronology; McArras Brook Formation
Open Access
Carboniferous Sarcopterygian Fossils and the Marine Paleoenvironment of the Joggins Formation, Nova Scotia, Canada
(2025-04) Brooke T. Reid
Joggins Fossil Cliffs, a UNESCO World Heritage Site in Nova Scotia, Canada, is known for its Late Carboniferous (Pennsylvanian) coal seams and remarkably preserved ecosystems that represent terrestrial tropical Pangea. Of the five formations present, the most significant is the Joggins Formation (Fm) which is divided into approximately 15 sedimentary cycles based on the alternation of flooding plains, coals, and channel bodies. While the site records cyclic terrestrial and marine deposits, the marine influence of the Joggins Fm has rarely been studied. As a result, many fish fossils in the Joggins Fm collection remain unidentified, and there are ongoing debates about the source of the marine influence. I aim to (1) identify five unidentified sarcopterygian fish fossils from the Joggins Fm, and (2) determine their habitat and depositional environment. I have selected seven sarcopterygian fish fossils, most of which are scales, and I identified them to the family level using relevant literature. To learn more about the marine influence at a specific location within the formation, a carbonaceous limestone was chosen as a representative specimen for the marine depositional environment based on its thickness and history of producing determinate fish fossils. Thin sections were made for a vertical representation of the limestone band as well as a sedimentary log for greater marine influence context. Both thin section and microfossil analysis shows extensive bivalve and ostracod fossils layered in organic matter. Phosphate and bone fragments can also be seen in thin sections. The fossil assemblage for this location within the Joggins Fm suggests a paleoenvironment with moderate marine influence, likely a brackish or estuarine environment. Lastly, this work contributes to our complete understanding of both the terrestrial and marine environments of this important site and the animals that lived within it.
Open Access
Using Short-Transported Tills as a Method of Increasing Mineral Exploration Efficiency in Southwestern Nova Scotia
(2025-04) Bailey R. Grondin
Till is subglacially-derived sediment deposited metres to hundreds of kilometres downflow from its source. In Canada and other glaciated regions, exploration for bedrock ore is challenging due to till coverage, explorationists seek ore-associated minerals or geochemical signatures in tills. However, there is limited exploration procedures optimizing the knowledge that if a mineral or geochemical anomaly occurs in a short-transport till, there is a greater probability of discovering its source. This research focuses on determining how short-transported tills can be identified. Here, I determine if short-transported tills can be distinguished from long-transported tills in southwestern Nova Scotia, improving dispersal tracing in regions with multiple glaciations. Field methods included analyzing clast lithologies, macrofabrics, and bulk densities. Laboratory methods included using radioactive terrestrial cosmogenic nuclides (TCNs) to date surface till in East Kemptville and determine the duration of time that the Salmon River sands were buried. Three boulder samples from East Kemptville yielded a mean age of 15.2 ± 0.4 ka, representing the first use of TCNs to date the deglaciation of southwestern Nova Scotia. A burial sample from the Salmon River Sands contained a relatively high 10Be concentration (1.68x 106 ± 3.74 x 104 atoms/g in quartz), indicating an age can be calculated once 26Al data is available. Future work will process ten additional burial samples from Salmon River and Mavillette to constrain the age of these deposits. Previous surface mapping identified both stony tills and matrix-supported tills in the region. Stratigraphy, geochemistry, and geochronology confirm at least five tills, most are longtransport tills from the north and west. The uppermost till at the Salmon River section (i.e. Beaver River Till) is a short-transported till, another exists above an angular unconformity at the base of the Mavillette section, possibly derived from pre-glacial fluvial or beach gravel deformed by glaciation. By using sedimentology, stratigraphy, geochemistry, and chronology, I evaluate regional tills, assign relative and numerical ages, linking them to paleo-ice flow dynamics and classify them as a short- or long-transport till. I conclude with a discussion of a field strategy for explorationists to establish if they are sampling short-transport tills.
Open Access
Increasing Evergreen Trees Reduces Soil Nitrogen and Aboveground Biomass Accumulation in Canadian Forest Plots
(2025-04) Alexandra Pell
Forests mitigate global warming by sequestering 45% of the world’s terrestrial carbon (C), keeping it out of the atmosphere where it amplifies global warming as a greenhouse gas. Carbon is stored in forests within woody tissues and soil organic matter (SOM). Nitrogen availability can limit plant growth and SOM stocks. Understanding which variables increase soil C, N, and ecosystem productivity is of interest in climate change mitigation efforts. Using data from the Canadian National Forest Inventory, we built Linear Mixed Effect Models to investigate the effects of symbiont affiliation, wood carbon: nitrogen ratio (C:N), and evergreen/ deciduous status on changes in soil C and N and aboveground biomass over a 10-year period. We found that decadal change in plot biomass decreased with evergreen dominance and increased with higher mean annual temperature. In the organic and mineral soil horizon, soil N decreased in plots with higher initial soil C: N ratios. C accrual in the mineral horizon decreased in plots with higher initial soil N stocks. N accrual in the organic horizon decreased with evergreen dominance as well (p <= 0.1). Interestingly, symbiont affiliation or wood C:N did not have a significant effect on soil C or N accumulation in either soil horizon. Forest stands with higher proportions of evergreen trees were associated with less biomass and soil N accrual over a decadal timeframe, possibly due to litter quality and microbial decomposition dynamics. In the face of a rapidly changing climate, maintaining forest productivity and C storage is highly pertinent. Understanding the factors that impact aboveground biomass and soil C and N accrual can help inform proper forest management, build accurate terrestrial biosphere models, and ensure that Canadian forests can continue to sustain growth and sequester C. Keywords: Canadian Forests, Soil Carbon Stocks, Soil Nitrogen, Symbionts, Evergreen and Deciduous Trees, Wood Nutrients
Open Access
Drone-Based Optical and Thermal Remote Sensing for Salmonid Habitat and Hydrological Applications in Eastern Canada
(2025-04) Alex Bevilacqua
Remote sensing has long been a valuable tool in environmental monitoring, with applications spanning hydrology, aquatic ecosystem management, and watershed research. Habitat degradation, including river warming, poses a significant threat to cold-water anadromous fish populations. Mapping of river habitats with satellite imagery is often limited by coarse spatial resolutions especially in the thermal band. Advancements in high-resolution drone-based optical and thermal surveying presents an efficient approach for mapping and monitoring salmonid habitat, particularly cold-water refugia in thermally stressed rivers, as well as groundwater-surface water interactions. This study surveyed two rivers in Prince Edward Island using photogrammetry and GIS workflows for image processing and analysis. By integrating optical and thermal datasets, the developed workflows provide a comprehensive approach to modelling riverine environments. Applications include watershed monitoring, habitat conservation, and telemetry research, such as analyzing habitat selection and fish behavior in thermally stressed rivers. Surveys were conducted in fall 2024 using a DJI Mavic 3T Enterprise drone equipped with RGB (12 MP and 48 MP) and thermal infrared (640 × 612 px) sensors. Photogrammetric ortho-mosaics, digital surface models, and GIS-derived data layers were generated to assess in-stream and riparian habitat. Data processing involved RStudio and ArcGIS Pro for spatial analysis (e.g., supervised classification, point sampling, zonal statistics), while initial photogrammetric reconstructions were performed using Agisoft Metashape. Results demonstrated how drone-based thermal imaging effectively captures fine-scale thermal heterogeneity, supporting habitat assessment and hydrological modeling. Generalized additive models were used to analyze temperature variations in relation to key environmental variables. Discussions include best practices for reporting uncertainty, mitigating methodological pitfalls, and integrating drone-based remote sensing into ecological and hydrological research. These findings highlight the potential of drone-based approaches to support movement ecology, watershed management, and conservation planning.
Open Access
Defining the phenology of early breeding behaviours of Leach’s storm petrels in the northwest Atlantic (Hydrobates leucorhous)
(2025-04) Sasha S. Chilibeck
Laying date is one of the most important reproductive fitness metrics in birds, as timing it well optimizes food availability and ensures the best chance at reproductive success. This is especially pertinent for Leach’s Storm Petrel, a declining seabird species in Atlantic Canada, , as they have low reproductive capacity. At present, our understanding of the timing of early reproductive behaviours for Leach’s Storm Petrels in the northwest Atlantic is minimal, limited to rough estimates of hatch date based on chick measurements. This study’s goal was to determine the timing of early breeding phenology for Storm Petrels from a dataset of geolocation sensor data (GLS) for six long-term study colonies: Kent, Bon Portage, Country, Middle Lawn, Gull, and Baccalieu islands. GLS data describes location and activity of tagged individuals through recording environmental light levels; as Storm Petrels are burrow nesting seabirds, GLS light data can determine when they occupy their burrow during the day. I aimed to characterize the timing of first burrow re-occupancy, differences in pre-laying activity between the sexes, and the lay-dates or start of incubation behaviour across the study colonies. Linear and generalized linear mixed models were run to determine if sex, colony, or year had a significant effect on breeding phenology. We found that colony significantly impacted the timing of first burrow re-occupancy and lay-date/start of incubation, with Kent Island, New Brunswick, having the earliest first burrow arrival and lay-date, and Middle Lawn, Newfoundland, having the latest of both phenologies. Year significantly impacted the timing of first burrow re-occupancy, as 2015 had the earliest arrival date. These findings indicate that when Storm Petrels return to their breeding colony, they may be influenced by global ocean climatic conditions (annual differences), but that lay-date/start of incubation is mainly influenced by localized conditions at the colony. Sex significantly impacted pre-laying burrow activity, with males visiting the burrow considerably more often and for longer periods than females, but females had a longer pre-laying exodus. Our findings may aid future research on Leach’s Storm-Petrel reproductive success by informing conservation management regarding the timing of key breeding activities. Keywords: Pre-laying exodus, timing of breeding, Procellariforms, reproductive strategies, geolocator, light sensor
Open Access
Chemically Characterizing Native Nova Scotian Freshwater Turtle Nest Scents for Olfactory Misinformation Applications
(2025-04) Robyn V. Hirsch
All native freshwater turtle species in Canada are currently in decline, including four species found in Nova Scotia. One major threat they face is high rates of nest predation, particularly by mammalian predators, which limits successful population recruitment. This problem is exacerbated by habitat loss, forcing turtles to nest in areas that are easily accessible to human-subsidized predators. Current nest protection methods (e.g., nest cages) are costly and inefficient, creating the need for improved methods of predation prevention to meet government mandates to protect turtles. This study proposes a conservation approach known as olfactory misinformation, which targets predators’ reliance on scent to locate nests. Conditioning predators to ignore unrewarded scents mimicking those of vulnerable prey, the method aims to camouflage real nests within the environment. The objective was to identify volatile organic compounds (VOCs) characterizing nest scents of freshwater turtle species native to Nova Scotia to guide the development of artificial scent solutions for use in olfactory misinformation strategies. This study combined field and lab work; swab samples were collected from adult female turtles and hatchlings during the 2024 nesting season, then analyzed using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry. Across all (n=49) samples, a diverse array (n=160) of volatiles were detected. Focusing on the most frequently observed VOCs found in the highest concentrations across samples revealed linalool oxide and 2-ethylhexanol as key volatiles characterizing nest scents for all species of Nova Scotian freshwater turtles. These VOCs, emitted by both adult turtles and hatchlings, enable the development of a single, generalized scent solution that can be applied to protect all turtle populations during both spring and fall predation seasons. Other volatiles were specifically characteristic of either cloacal fluids (e.g.,2-pentylfuran and 2-butoxyethanol), epidermal secretions (e.g., 3-methylcyclopentyl acetate and 5-hepten-3-yn-2-ol, 6-methyl-5-(1-methylethyl)), or hatchlings (e.g., mesitylene and limonene), their identification allowing for the creation of more complex scent solutions. Future steps of this project will involve testing the solution’s ability to attract mammalian predators in field trials and eventually condition them to ignore the unrewarded scent, making it the first olfactory misinformation approach to utilize artificial scents. Keywords: olfactory misinformation; turtle nest predation; freshwater turtle conservation; volatile analysis.
Open Access
Exploring the terrestrial carbon sink at a global scale: the effects of nitrogen fixation, nitrogen deposition and CO2 fertilization
(2025-04) Paige MacCarthy
Rising atmospheric CO2 concentrations have reached 51% above the pre-industrial level. The terrestrial carbon sink performs a critical role in sequestering atmospheric CO2, thereby mitigating the rate of climate change. The terrestrial carbon sink is primarily driven by CO2 fertilization, but the extent of this driver is constrained by nitrogen limitation. However, biological nitrogen fixation can fuel CO2 sequestration and relieve nitrogen limitation. Exploring global change drivers, CO2 fertilization, and nitrogen deposition, provides crucial insight into how biological nitrogen fixation will respond to future climate scenarios. Therefore, we conducted an analysis of terrestrial biosphere model outputs was also conducted to compare the influence of CO2 fertilization and nitrogen deposition on biological nitrogen fixation rates at a global scale. We found a significant increase in biological nitrogen fixation rates from elevated CO2 concentrations. A global meta-analysis of terrestrial biological nitrogen fixation in response to elevated CO2 concentrations across various ecosystems was also conducted to evaluate the model. We found that the empirical effect of elevated CO2 (0.00393 ppm-1) closely aligns with the modelled effect of elevated CO2 on the rate of biological nitrogen fixation (0.00156 ppm-1). In addition, our study found that global biological nitrogen fixation mean attribution to CO2 concentrations was 19.7 Tg N yr-1, and -1.63 Tg N yr-1 for nitrogen deposition. Overall, insights from this study contribute to our understanding of how the terrestrial carbon sink and nitrogen cycling processes may respond to future environmental variability, particularly in the context of rising atmospheric CO₂ concentrations.
Open Access
Investigating the effects of forestry road crossings on stream habitat health and benthic macroinvertebrate communities in Napu’saqnuk (the St. Mary’s River watershed) in Mi’kma’ki (Nova Scotia)
(2025-04) Mary Legorburu
Napu’saqnuk (the St. Mary’s River) is a culturally, economically, and recreationally significant watershed in Mi’kma’ki (Nova Scotia). Napu’saqnuk provides habitat got the endangered Southern Upland Designatable Unit of Atlantic salmon (Salmo salar) and other species protected under the Endangered Species Act and Species at Risk Act. Historical and current forestry activities (harvesting and roads) are expected to be degrading stream habitat health and contributing to the decline of the Atlantic salmon population in Napu’saqnuk. Under the Fisheries Act, fish and fish habitat are protected, emphasizing the importance of understanding how forestry affects stream health. Benthic macroinvertebrates (BMI) are biological indicators of freshwater ecosystem health. BMI community structures are compared between disturbed and undisturbed habitats to assess whether disturbance has reduced habitat quality. BMI Orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are sensitive to disturbance and tend to decline in degraded habitats. To assess stream health, BMIs and stream habitats were sampled upstream and downstream of road crossings in 12 streams. BMIs were subsampled and identified at the family level. Community structure was analyzed using community metrics, diversity indices, and multiple linear regression (MLR). T-tests were used to compare stream habitats and community structures between upstream and downstream of crossings, and between streams with culverts and bridges. Findings showed road crossings steepened stream gradient downstream, possibly due to improper road crossing design. However, this did not negatively impact stream health. Community structures and other habitat characteristics were similar between upstream and downstream of crossings. Streams with culverts and bridges reflected two distinct stream types, likely due to their location in the watershed- culverted streams were closer to headwaters and bridge streams were near the West River (main river in West Branch). Differences in habitat and community structures reflect natural habitat variation across a watershed, not differences in stream health. Most streams met habitat requirements for juvenile Atlantic salmon, suggesting the presence of healthy habitat in the West Branch. Ongoing monitoring and a greater focus on harvesting impacts are recommended. Findings can inform forestry management and Atlantic salmon habitat conservation in Mi’kma’ki. Keywords: Stream health; benthic macroinvertebrates; Atlantic salmon habitat; St. Mary’s River watershed; road crossings; culverts
Open Access
Fighting Future Flames: Modelling Forest Fire Vulnerability in Nova Scotia, Canada
(2025-04) Grace C. Kasouf
Historically, fire has been, and continues to be, a natural driver of forest renewal and regrowth, shaping Earth's landscapes into what we see today. The complex relationship between changing climate patterns, fuel types, and human activity has contributed to an increase in the frequency of forest fires. An effective method to quantify and monitor the changes to a forest ecosystem is the use of integrated remote sensing and spatial analysis techniques. In the summer of 2023, Nova Scotia experienced their most devastating fire season with 220 fires burning 25,093 hectares of land, highlighting the growing importance of monitoring forest fire vulnerability. The goal of this study is to develop a suite of indicators that, when considered together, identify areas at potential high-risk of forest fires in Nova Scotia. Two study areas were considered: Upper Tantallon and Barrington fire locations from the summer of 2023 in Nova Scotia, Canada. An ISODATA unsupervised classification was performed to identify patterns of similar spectral characteristics among biophysical variables that was used to create a map of forest fire vulnerability using an ordinal scale. The input variables include spectral indices like Normalized Difference Vegetation Index, Normalized Difference Moisture Index, slope and proximity to human-built areas, as identified across several previous studies. The vulnerability scale was tested against a high accuracy burned area classification that was generated through band differencing Sentinel-2 derived NBR (kappa 0.905). In this validation there was a high level of agreement between burned and vulnerable areas in both the reference and the map at both locations. Therefore, a significant number of areas classified as vulnerable did burn in the resulting fire. There was low agreement between the not burned and not vulnerable areas in both the reference and the map at both locations; however, this could have been caused by fire control efforts in those areas. The results of this study will help improve future wildfire science towards forest fire prediction to increase disaster preparedness and decrease the damage of forest fires. Keywords: Forest fire; Remote sensing; Vulnerability; Unsupervised classification; Nova Scotia
Open Access
Examination of the unique preservation and identification of enigmatic fossil tree specimens from Nova Scotia
(2025-04) Wednesday Gillespie
The geological and paleobotanical history of Nova Scotia is rich and diverse. Sites such as the Joggins Fossil Cliffs and the Sydney Coal Mines have been studied extensively, but studies on fossil tree specimens from other localities are lacking. This study examines two mineralized tree specimens from the Carboniferous Period, one preserved in marine gypsum from Miller Creek (Gypsum Tree - NSM022GF16.1) and one preserved in fluvial deposits from Cheticamp (Cheticamp Tree - NSM024GF22.1). Both specimens share a similar external morphology, which this study aims to examine with the following questions: 1) identify the specimens based on their vascular anatomy, 2) determine if they are taxonomically related, and 3) conduct a mineral analysis to determine the process of mineralization. An extensive literature review was conducted to determine applicable taxonomic groups and modes of preservations. Transverse and longitudinal thin sections were taken of both specimens, and were examined using optical microscopy and scanning electron microscopy (SEM). The Gypsum Tree has well preserved cell structures with pycnoxylic cell bands showing signs of soft tissue, mineralogical, and structural deformation. The Cheticamp Tree has poorly preserved cells in pycnoxylic cell bands and extensive mineralogical deformation, resulting in nodular growth around fragmented permineralized nuclei. Scanning electron microscopy results show that the Gypsum Tree is composed primarily of CaCO3 with pyrite inclusions. The Gypsum Tree is composed primarily of iron-rich dolomite with a small pocket of exquisitely preserved cells in a SiO2 inclusion. Based on the pycnoxylic arrangement of the secondary xylem, both specimens have been identified as belonging to the order Cordaitales. The Gypsum Tree was likely transported from a near-shore environment to a shallow marine depositional system before being buried and mineralized in marine gypsum. The Cheticamp Tree likely underwent moderate decomposition before being buried in an anoxic brackish environment, which facilitated the mineralization of dolomite nodules. In conclusion, this study found that the two fossilized tree specimens were taxonomically related, both belonging to the order Cordaitales. They were deposited in two different paleoenvironments, and underwent different levels of soft tissue, mineralogical, and structural deformation as they were mineralized. Keywords: fossil wood, Carboniferous, Nova Scotia, taphonomy, cordaites.
Open Access
Provenance and Depositional History of the McAras Brook Formation, Antigonish County, Nova Scotia
(1977-03-15) Fralick, Philip W.
The McAras Brook Formation was deposited in the Merigomish Structural Basin during the upper Mississippian. The lower conglomeratic member was deposited by alluvial fans. The detritus accumulated along both sides of the fault-bounded basin. Periods of basement instability are reflected by basalt flows present in the lower member. Movement of the Hollow Fault caused a major change in the drainage pattern. A fluvial system advanced over the alluvial fan at the type section. The fault movement causing this may have been the southern Antigonish Massif rising while the northern section sank. The fluvial system flowed over this sunken area. During deposition of the lower member at the type section, the Knoydart Formation was exposed to the south of the Hollow Fault. The Browns Mountain Group became exposed during deposition of the Knoydart Brook section. The upper strata of the Browns Mountain Group was predominantly green quartzite during the Mississippian. These units have been completely eroded since Mississippian time. Browns Mountain lithologies present during the Carboniferous at the tip of Cape George were of the same lithologies as those outcropping today. Keywords: Pages: 80 Supervisor: Paul Schenk
Open Access
Paleoenvironment of a Small Portion of the Gay's River Carbonate Complex (Carboniferous), Gay's River, Nova Scotia
(1977-03-15) Hartling, Affred A.
In the past, the Gay's River Carbonate Complex, Gay's River, Nova Scotia, has been largely described as an ecologic reefal buildup. This now appears to be a false use of terminology, as the carbonate complex is found to comply favourably with typical lime mud mound development in modern and ancient environments. The detailed study of three diamond drill cores, provided by Imperial Oil Ltd., has outlined four distinct stratigraphic units, identified by faunal assemblage, lithology, and/or textural criteria: (1) Basal Siliceous Unit, (2) Algal-Skeletal Unit; (3) Fenestral Unit; and (4) Cap Unit. The thin, basal unit is found overlying an erosional contact which offers approximately 35 feet of relief. This unit has been isolated on the basis of a higher content (greater than 15%) of siliceous material. The Basal Siliceous Unit grades abruptly into the thick Algal-Skeletal Unit. The Algal-Skeletal Unit is dominantly composed of algal-skeletal wackestones and algal boundstones. The skeletal grains, found floating in a carbonate mud, are mostly thin shelled brachiopods and bryzoa, with gastropods, corals, and ostracods often associated. Gradationally overlying the Algal-Skeletal Unit is the thick Fenestral Unit, dominated by fenestral-algal boundstones. Fenestral fabrics are abundant throughout the unit, with skeletal grains, similar to those of the underlying unit, occasionally present. The upper Fenestral Unit has been eroded by Pleistocene glacial activity over most of the study area. A thin Cap Unit is found gradationally overlying the Fenestral Unit at one locality. The Cap Unit is dominated by skeletal wackestones. Thin shelled, generally fragmented gastropods and brachiopods form the bulk of the skeletal grains found. The succession of stratigraphic units is interpreted as a transgressive mud mound buildup. As Windsorian sea level rose, a paleotopographic ridge system, with associated talus debris, was flooded. The physiographic nature of the ridge system resulted in the formation of a small, semi-restricted bay. Thus, the talus slope, inside the bay, was reworked by tidal currents and infrequent storm activity. The reworked talus material combined with carbonate deposition in formation of the Basal Siliceous Unit. The colonization of the sea floor by corals, brachiopods, bryzoa, and Porostomata baffled the tidal currents active within the bay. The accumulation of carbonate mud around the initial baffles lead to the formation or small, localized mounds. As these small mounds grew and were colonized by an increasing number of baffling organisms, current restriction increased. Mounds began to merge, and eventually a large bank-like structure was formed. This bank is defined as the Algal-Skeletal Unit in the stratigraphic succession. As sediment continued to accumulate, the bank began to shoal, and a tidal flat developed. An increase in salinity nearshore restricted the occurrence of grazing organisms, and algal mats grew relatively unhampered. These algal mats aided the formation of fenestral fabrics in the intertidal-supratidal zone. This intertidal-supratidal zone is present in the stratigraphic section, and is defined as the Fenestral Unit. As sea level continued to rise, the bay became subjected to increasing wave activity. The baffling organic communities were destroyed, and salinity decreased nearshore. wave activity piled up beach ridges, rimming the supratidal flat. These supratidal beach ridges are found within the Cap Unit. Keywords: Pages: 134 Supervisor: Paul Schenk
Open Access
A Sedimentological Study of the Shoreline Deposits of the Lawrencetown Beach Area
(1977-03-15) Hattie, Stirling Stewart
The two main types of transportation media of sand grains are wind and water. They lead to deposition of postula which may or may not be distinguished as aeolian or water-laid. This project will deal with the existing techniques in analysis of sand samples with emphasis on the process of distinguishing between beach and dune sands from laboratory procedures. The study location chosen is the Lawrencetown Beach area. Mention will also be made of the existing conditions which are playing a part in shaping the face of Lawrencetown Beach~ Field work for the project was undertaken in February and March of 1971, and due to the weather, as complete a field study program as would have been liked, was impossible to carry out. Nevertheless, a number of samples and photographs were taken to be later analysed in the laboratory and the geology of the area was mapped. I would like to express my thanks to Bob Wilson who helped me set up and carry out the micro-sieving experiment, to Dr~ [.Milligan who showed me the correct procedures for making the maps, and to Dr. Fl.A.Gees who aided me with suggestions and advise throughout the project.
Open Access
The Spatial and Temporal Distribution of Foraminiferal Populations within Inner Miramichi Bay, New Brunswick
(1977-03-15) LaBerge, Michael
The stratigraphic distribution of Foraminifera in the Inner Miramichi Bay is described and compared to surficial paleontologic data reported by Bartlett (1966), Tapley (1969) and Scott et al (in press) from the same estuary. Three major assemblage zones presently occupy the stratigraphy of Inner Miramichi Bay: the transitional, marginal marine, and marsh foraminiferal assemblage zones. A marginal marine assemblage existed in surficial sediments during the field investigations conducted by Bartlett (1966) and Tapley (1969). These sediments have since been covered by 20 em. of mud supporting a transitional faunal assemblage. The vertical distribution of Foraminifera in the Inner Miramichi Bay was studied by means of statistical analyses of data extracted from 11 short gravity cores. A comparison of cluster analyses yield minor gradations existing within the limits of distinct assemblage zones. These gradations were resolved through an intuitive interpretation of the original data.
Open Access
Characterization of Calcite Amygdules in Devonian Basalts, in the McArras Brook Formation, Nova Scotia
(2024-04) Helmke, Ingrid
Along the North Shore of Nova Scotia, Canada vesicular basalts in the McArras Brook Formation are host to carbonate amygdules and veins. These basalts are interbedded within a well characterized Devonian strata but have not been directly dated. Through previous studies with U-Pb dating, the ages for calcite amygdules have been shown to form shortly after the eruption of the host basaltic lava. Secondary processes lead to the formation of overgrowths on existing calcite amygdules and low-T veins. These may form during tectonic emplacement and thus, multiple generations of calcite can also be found in the same suite of basaltic rocks. Before the U-Pb ages of both volcanism (amygdule formation) and later tectonic activity (secondary calcite) can be accurately measured and used as a proxy for the age of the basalt flows, the growth history of the calcite amygdules and viens must be carefully characterized. In this study we have used basic textural relationships and UV fluorescence to examine calcite growth history, both in the field and in collected samples. In-situ UV-fluorescence shows the growth of several generations of calcite amygdules and veins in the basalts from McArras Brook. We will use the UV characterization to help target analysis of different generations of calcite using a scanning electron microscope (SEM) to analyse the relationships between the fluorescence and the major elements. The results are expected to identify activator elements in the calcite which correspond to the differences in fluorescence colour, and correlate element compositions to the growth history. This will allow us to target the best areas for subsequent U-Pb dating of calcite to determine the absolute (volcanic) ages of these basalts, and the ages of secondary processes.
Open Access
Quantifying the Impacts of Nova Scotia Forest Management Practices on Forest Stand Albedo and Surface Temperatures
(2024-04) Rusnak, Evelyn
In an effort to mitigate climate change, the Canadian government has increased focus on natural carbon sequestration through afforestation (i.e., the planting of forests where there were previously no forests) and reforestation (i.e., the planting of forests to replace a forest than was removed or disturbed). Traditionally, these forest management practices have preferred coniferous (softwood) tree species, which has led to wide scale species conversion across Europe and North America, increasing coniferous forest cover. Recent studies have linked these forestation practices to increased surface temperatures in managed forests. Coniferous forests have lower albedo than deciduous forests, absorbing a greater ratio of solar energy, which is re-emitted as heat and raises surrounding temperatures. This thesis tested the hypothesis that forest management practices in Nova Scotia increase coniferous tree cover, which in turn reduces canopy albedo and raises surface temperatures. Remote sensing methods were used to test the relationship between forest treatments and stand biophysical characteristics. Albedo, surface temperature, and Normalized Difference Water Index outputs for Nova Scotia were derived from multispectral and thermal satellite imagery collected by Landsat 8 over July and August 2022. Forest stand data shared by the Nova Scotia department of Natural Resources and Renewables identify 216,235 forest stands, classified into two groups: 89,171 treated forest stands, and 127,064 natural forest stands. Analysis successfully demonstrated relationships between forest management practices and forest stand biophysical characteristics using remote sensing derived measurements. Contradicting the original hypothesis, treated stands exhibited higher mean albedo than natural stands, a process partially explained by the scarce canopy cover of young replanted forests. Further, mean surface temperatures in treated stands were 0.4-1.2 °C warmer than comparable natural stands. This relationship indicates current forestry policies may, in fact, be increased surface temperatures in managed forests. While further discriminant analyses failed to meet confidence thresholds, classification accuracies of ~70% suggest some discriminant ability within the predictor variables (albedo, surface temperature, and NDWI). The overall results of this thesis indicated that forest management is creating higher forest surface temperatures, but this phenomena is not related to decreased albedo in treated stands, and is likely caused by underlying processes not addressed in this study. The outcomes of this work call into question the efficacy and validity of using forests as climate change mitigators. Specifically, whether Canada should continue to implement climate change policies that promote reforestation and afforestation if these methods may warm surface temperatures. In-depth analysis assessing the value forestation as a climate mitigation strategy should be conducting; contrasting the cost of increased surface temperatures caused by forest management against the considerable carbon sequestration ability of forests.
Open Access
The impact of precipitation phase and aquifer type on changing groundwater levels in mountain regions of Canada and the United States
(2024-04) Salehi, Sana
Groundwater in alpine regions plays an essential role in downstream water supply. As the climate warms, mountain water resources are under threat with reduced snowpack, glacier recession, and precipitation phase change that can negatively impact summer streamflow. However, the extent to which such global changes can impact the mechanisms that contribute to groundwater recharge remains poorly understood. This project aims to address the limited spatial and temporal extents of observational studies and enhance our understanding of long-term trends across various geographical boundaries of groundwater in mountainous regions. We analysed a dataset of 171 observation wells from mountain regions across Canada and the US, categorizing wells as snow-dominated, rain-dominated, and high-temperature rain-dominated hydrological regimes based on temperature thresholds. Additionally, we considered three aquifer types (confined, unconfined, and mixed) and the well depth as the potential explanatory variables. We conducted Kruskal- Wallis and Spearman correlation analysis on the above against the groundwater level trends, respectively. Our results indicated a non-significant difference (p = 0.1687) between the three hydrological regimes, a statistically significant difference (p = 0.0182 < 0.05) in the trends observed between the three-aquifer type, and lastly a weak negative Spearman correlation of ρ = -0.01089 between trend and well depth, which is not statistically significant (p<0.05). This study emphasizes the value of extending research on mountain groundwater to a larger spatial extent and offers significant insights into how various factors can influence groundwater recharge in mountains.