Honours Thesis Interim Presentations

Gabriela Fuentes Waye

'Timing of Mafic Magmatism and Nature of Iron-Alkali-Calcic Metasomatism at Clarke Head, Nova Scotia'

Abstract: The main objective of this project is to constrain the timing of mafic magmatism at Clarke Head, Nova Scotia, and to discern its relationship to metasomatism along the Cobequid Chedabucto Fault Zone (CCFZ). Clarke Head is located within the CCFZ, a 300 km E-W striking, terrane bounding fault system that hosts numerous metasomatic iron ± copper, gold, and cobalt deposits. These occur within breccias with sodic and potassic alteration, suggesting a Metasomatic Iron Alkali Calcic (MIAC) mineralization model is relevant. The source of metasomatism along the CCFZ is speculated to be from the melting of Viséan-aged Windsor Group salts via magmatism. Field evidence and radiometric dates from mafic rocks north of the CCFZ indicate syn to post Viséan magmatism occurred. Undated mafic blocks at Clarke Head may be related to this magmatic pulse.

Clarke Head exposes mélange, bounded to the north along an E-W striking fault splay of the CCFZ, that incorporates blocks of varying size, lithology, age, and deformation history. Field observations show that Na-rich scapolite veins with alteration haloes are constrained within mafic blocks in the mélange. Drone imagery was collected to create 3D models of the mineralization relationships observed in these mafic blocks and to reach inaccessible outcrop in cliff face.  Future work will include micro-X-Ray Fluorescence (µXRF) mapping of host block lithologies and later mineralization to characterize alteration styles and build a paragenesis. Petrography of mafic blocks and scapolite veins will also be done to identify mineral geochronometers (e.g. apatite or rutile) to date magmatism and metasomatism using in-situ U-Pb Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). These results will be compared to similar mineralization and alteration styles along the CCFZ to evaluate the timing of mafic magmatism in the area and its relationship to metasomatic deposits.

Tamirira MBeri

'High temperature phase behaviour in environmental waste combustion furnaces'

Abstract: This study explores the behavior of sodium bentonite (an absorbent, swelling clay composed of mainly montmorillonite) in high temperature furnaces and its effect on the compositional and physical properties of hard ash, in particular its ability to weaken ash structure.  The objective of the study is to better understand how sodium bentonite additives mitigate “fouling” (adhesion of molten material to furnace surfaces) in furnaces that are utilized to burn environmental waste material, with the goal of maximizing furnace efficiency, and reducing operational costs. Using a high-temperature muffle furnace, pure samples of sodium bentonite, combusted fuel (e.g., hardwood ash), and varying mixtures of fuel and bentonite are being heated and held at T from 800 to 1500 ^oC. Final melting points for pure bentonites, pure fuels, and mixtures are being determined, followed by run product imaging under a binocular microscope for visual analysis, looking out for partial melting at lower temperatures and ensuring complete melting has occurred at the determined melting points. The composition of glass melt products are being analyzed by scanning electron microscope (SEM-EDS). Compositional data will be used to calculate various engineering parameters (e.g., slagging factor) and melt viscosity, all of which are related to fouling tendencies. Future work will utilize these data in increasing our ability to understand how the chemical composition of the ashes will need to be altered, as well as determine the ideal sodium bentonite composition, within an ideal temperature range that would allow for the generation of more viscous and friable ashes.

Jacob White

'Understanding elemental distributions in variably altered limestones of the Pleistocene Ironshore Formation, Grand Cayman, BWI'

Abstract: The objective of the current project is to map the elemental distribution of the altered and unaltered units of the Pleistocene (80-500 ka) Ironshore Formation on Grand Cayman, Cayman Islands, British West Indies, north Caribbean Sea. Addressing this objective will provide a better understanding of how pore fluids modify an isolated carbonate platform that has undergone varying degrees of meteoric diagenesis. This goal will be met using two methods: petrographic/microfacies analysis and micro–X-ray Fluorescence (µXRF) analysis. The first stage of study will involve a comprehensive petrographic analysis of  ~32 thin sections from each of the six units of the Ironshore Formation. In this stage representative thin sections will be chosen for detailed microfacies analysis where lithology, allochem abundance, porosity, and diagenetic features will be identified. The microfacies analysis will act as a guide for µXRF analysis. µXRF will be utilized to map major and trace element distribution to help determine the relationship between diagenesis and the elemental distribution of the allochems and their associated matrix material. Preliminary results show that the current understanding for diagenetic alteration and allochem identification in the study area are consistent with samples examined in this project in terms of microfacies characteristics. Units E-F are visually pristine and chemically unaltered units, whereas units A, C, and D are minimally altered with cementation, but chemically altered, and unit B is visually and chemically altered. Ongoing work will characterize chemical alteration within the units of the Ironshore Formation to study pore fluid movement throughout this isolated carbonate platform, a process which may have significant applications for petroleum reservoirs.

Isaac MacDonald

'Characterization of fluid in bitumen-carbonate-quartz veins in the Albert Formation'

Abstract: This research will evaluate whether the fluid inclusion record preserved  in carbonate and quartz within bitumen-carbonate-quartz veins cutting through the hydrocarbon-bearing (e.g., bitumen, kerogen, oil and gas) rocks of the Albert Formation, Moncton Subbasin, southern New Brunswick, can be used to constrain the physicochemical conditions of  hydrothermal activity that pervaded this subbasin. Detailed fluid inclusion work has not been performed in this setting, and will thus strengthen our understanding of the hydrothermal history affecting the subbasin. This work will be applied to elucidating, the hydrocarbon fertility and fossil fuel potential of southern New Brunswick.

Raman spectroscopic analysis of the vein-hosted bitumen, as well as fragments of accidentally entrapped bitumen in petroleum-rich fluid inclusions, is done to determine maximum temperatures of vein formation. Microthermometric analysis of fluid inclusions is done to determine the minimum pressure and temperature of fluid entrapment. In-line, rock-crushing gas chromatography will be done on individual quartz crystals containing hydrocarbon fluid inclusions to determine the composition of volatile species in the fluid (up to C8 hydrocarbons).

Preliminary results from microthermometry show a minimum temperature of entrapment between 70°C and 120°C. The preliminary results from analysis of the Raman spectra show the maximum temperature of the vein to be 170°C with a standard deviation of 20°C. Raman spectroscopy, microthermometry, and GC-FID/TCD will continue being done on samples from the Albert Formation to get a more robust dataset.