Honours Thesis Defense

Gracie Avery Gracie is a fourth-year student studying geology at Saint Mary’s University. Her interest in the oil and gas industry was sparked during her time at SIFT, where she had the opportunity to meet fascinating people and examine interesting rocks. After returning from the mountains in September, she began working on uranium geochemistry. When not at school, she enjoys hiking or climbing with friends.

'The Source of Uranium for the Lac Cinquante Uranium Deposit, Nunavut, Canada'

Abstract: The Lac Cinquante uranium deposit is hosted in an Archean greenstone belt below the Paleoproterozoic Baker Lake Basin, Nunavut, and is currently characterized as a vein-type uranium deposit. Vein-type uranium deposits are usually spatially associated with granitoids and consist of uranium mineralization concentrated in fractures, shear zones, and stockworks. The source of uranium in the Lac Cinquante is unknown and is determined in this study through petrographic work and trace element analysis of uranium minerals. We hypothesize that the uranium was sourced in one of two ways: either uranium was leached from apatite, zircon, or monazite, from nearby c. 1.84 Ga Hudsonian granites or the uranium was sourced from glass of the potassic volcanic rocks (Christopher Island Formation; CIF) of the Baker Lake Group. Petrographic work including micro-XRF mapping and scanning electron microscopy confirm the complete paragenesis: i) primary minerals of the host rock including plagioclase and quartz, ii) albitization of plagioclase, iii) formation of uraninite, brannerite, hydrothermal zircon, apatite, (± barite, pyrite, chalcopyrite, molybdenite, sphalerite, and galena) in calcite and albite veins, and iv) hematite, carbonate, and chlorite alteration. Pervasive albitization of the host rocks, the complex mineralogy (brannerite, hydrothermal zircon, apatite), and the distinct geochemistry (high Ti, Ba, Zr) indicate reclassification of this deposit as Na-metasomatic uranium deposit is warranted. Furthermore, trace element data of uraninite and brannerite reveals four distinct chondrites normalized REE patterns with flat (i.e. none) to positive Eu anomalies and enrichments in LREE/HREE. These profiles are inconsistent with a granite source but are similar to the CIF. The ore minerals are also high in Ti, Ba, Zr, and Sr, also consistent with CIF geochemistry that is more enriched in these components than the Hudson granites.

Macy Giles Macy is a fourth-year honors student working toward completing a double major in Environmental Science and Geology. She is passionate about protecting coastal environments and enjoys studying the intersection of human activity and the natural environment. With plans to pursue a master’s degree after graduating in the spring of 2024, she is dedicated to furthering her education. In her free time, she enjoys beekeeping, hiking, gardening, and reading.

'Examining Drivers of Ecomorphodynamic Change in the Avon River Estuary'

Abstract: The Avon River Estuary is a hypertidal, muddy estuary in the upper Bay of Fundy. The system has been in dynamic equilibrium since construction of the causeway in 1970, but recent construction activities and changes in tide gate management have caused an observable shift to disequilibrium. To assess the environmental consequences of these activities, we will examine the relative influence of natural and anthropogenic drivers of ecomorphodynamic change within the Avon River, downstream of the Highway 101 causeway by comparing data from 2019-2023 to baseline conditions, 2007-2019. We hypothesize that anthropogenic activities will hold strong influence over the system ecomorphodynamics. To evaluate shift occurring in the system we examined changes in channel cross sectional profiles, cross sectional area, changes in surface elevation, volumetric changes, sediment grain size, and vegetated area. We then compared these changes to tide gate manipulation information, construction activities, tidal cycles, and precipitation data to infer what may be influencing the change. Results indicate that there has been a quantifiable change in ecomorphodynamics between the baseline period and the study period. Additionally, most of the notable changes that occurred were concentrated around the Windsor Marsh and the Newport Bar, near the causeway. Based on patterns in natural and anthropogenic influences as well as the locations of changes, we believe that construction has had strong influence on the Avon River Estuary while the St. Croix River is mostly unaffected by anthropogenic interference and precipitation may hold primary influence. While future studies need to be conducted and should be based closer to the causeway, these results provide insight into how estuaries experiencing significant anthropogenic interference may respond and adjust.

Youssef Yammine

Youssef is a fourth-year geology student currently writing his honours on lithium pegmatites and set to graduate in April. When not studying or working, he enjoys movies, reading books, and playing soccer. Youssef plans to work after graduating and pursue a master’s degree soon after.

'Developing mineralogical and geochemical discrimination methods to classify Li-barren and Li-prospective pegmatites in southwestern Nova Scotia'

Abstract: The parental magma composition that produces a plutonic rock is what gives the lithium bearing pegmatite its distinct elemental composition. These magmas have very high concentrations of specific incompatible trace elements that differentiate them from other types of pegmatitic magma. A sought-after incompatible element, lithium, is challenging to detect through most routine analytical techniques. It occurs in abundance most commonly bonded within aluminosilicate minerals; for example, as the lithium aluminium silicate mineral spodumene (LiAlSi2O6). The current research is focusing on the detection of this element in prospective terranes aided geological and geochemical data. The practical goal of the study is to be able to predict the occurrence of lithium-rich pegmatites that may not contain the spodumene at a site of pegmatite dyke exposure but that contain hidden spodumene inventory. In other words, the goal is to find a “fingerprint” that can indicate the presence of geologically lithium-rich minerals. The main objective is to investigate if we can use the chemical composition and mineralogy of chemically developed rocks to differentiate between economic and sub-economic lithium rocks in the absence of spodumene. The first step is to follow the classification system based on the paper by White and Müller (2022). Granitic pegmatites can be classified into three different sections, into which the samples are grouped in by running a thin section analysis to determine the main and accessory minerals, using the SEM to confirm some of the data. The second step is discrimination; running a principal component analysis using the data acquired to further find out where lithium is occurring. The third step is to look at the larger picture and run soil analyses in the study area, namely Brazil Lake in southwestern Nova Scotia. Soil analysis in remote areas will help locate lithium-rich outcrops by studying soil dispersion, but to ensure reliability, the marker first needs to be identified. This research is meant to find a way to facilitate lithium detection and to more reliably uncover lithium prospective deposits.