Other Earth Sciences Commons^™

The Fate Of Carbonate Rocks During Hypervelocity Impacts: Case Studies From Three Impact Structures On Earth, Nicolas D. Garroni

Electronic Thesis and Dissertation Repository

Approximately 28% of all hypervelocity impact structures discovered on Earth exist in a carbonate-dominated target sequence. Despite decades of research, how carbonate rocks and minerals react to shock metamorphism is still poorly understood. In this contribution, three impact structures on Earth were studied to determine the effects of shock metamorphism on carbonate minerals: Chicxulub, Crooked Creek and Jebel Waqf as Suwwan.

At Chicxulub, carbonates from the impact-melt bearing breccia of drill core, M0077A were characterized petrographically and geochemically. Calcite was the only carbonate mineral present and is abundant throughout the impact breccia in five distinct varieties: limestone clasts …

Oxygen Speciation In Potassium Silicate And Potassium Aluminosilicate Glasses: Insights From X-Ray Photoelectron Spectroscopy, Ryan Sawyer

Electronic Thesis and Dissertation Repository

In a geological context, glasses are useful analogues for silicate melts as they are more readily studied in the laboratory using a wide range of techniques that are impractical for molten liquids. Understanding the structure of binary silicate glasses can help us understand more about the magmatic processes that affect terrestrial planetary bodies.

Potassium silicate glasses ranging in composition from 10 mol% to 35 mol% K₂O were studied using X-ray Photoelectron Spectroscopy (XPS). From high resolution O 1s XPS spectra, Bridging Oxygen (BO) mole fractions were calculated and compared with those of previous ²⁹Si MAS NMR studies. …

Investigation Of Sulphide-Poor Gold Mineralization At The Deep A Zone, Kiena Complex, Québec, Stephanie A. Kobylinski

Electronic Thesis and Dissertation Repository

The Kiena Complex is located halfway between Malartic and Val d’Or in Québec, within the Abitibi Greenstone belt in the Superior Province. This study examined mineralization at the Kiena Complex using detailed core logging, geochemical analysis of wall rock, petrography, EPMA, and gold deportment studies. The analysis and interpretations indicate that the unique sulphide-poor gold-rich quartz veins of the Deep A Zone at the Kiena Complex contain 500 μm²) are located at the contact of quartz and corroded albite grains, and fine gold grains (5-500 μm²) are hosted within the corroded albite.

Developing A Bytownite Calibration Curve As A Lunar Analogue, Trevor W. Matterson

Undergraduate Student Research Internships Conference

Planetary analogue materials are useful to help interpret and predict planetary processes on other planetary bodies that we cannot observe directly. Lunar analogue materials include terrestrial rocks and minerals with compositions and textures like those on the moon. This project investigates the lunar analogue mineral bytownite to quantify shock effects on the moon using strain related mosaicity determined through micro x-ray diffraction (µXRD). Calibrating strain information as a function of shock pressure for these minerals will enable us to extract peak shock pressures (in GPa) from naturally shocked materials, such as lunar meteorites and Apollo samples, using µXRD

Rare-Metal Alkaline Granite From The Arabian Shield, Saudi Arabia, Abdullah A. Aseri

Electronic Thesis and Dissertation Repository

Mineral deposits of high field strength elements (HFSE) and rare earth elements (REE) are commonly within granites that have experienced strong post-magmatic alterations. There has been a long debate on whether the mineralization is due to magmatic and/or hydrothermal processes. The Arabian Shield hosts several economical rare-metal alkaline granites that are poorly understood. This work aims to evaluate the nature of the mineralization in three rare-metal granites from the Arabian Shield, showing distinct mineralization styles ranging between disseminated mineralization at Al-Ghurayyah, pegmatite and hematized granite at Jabal Sayid, and quartz veins at Dyaheen.

The granites from all three areas are …

Tree-Ring Isotopes Adjacent To Lake Superior Reveal Cold Winter Anomalies For The Great Lakes Region Of North America, Steven L. Voelker, Simon S.-Y Wang, Todd E. Dawson, John S. Roden, Christopher J. Still, Fred J. Longstaffe, Avner Ayalon

Earth Sciences Publications

Tree-ring carbon isotope discrimination (Δ¹³C) and oxygen isotopes (δ¹⁸O) collected from white pine (Pinus strobus) trees adjacent to Lake Superior show potential to produce the first winter-specific paleoclimate reconstruction with inter-annual resolution for this region. Isotopic signatures from 1976 to 2015 were strongly linked to antecedent winter minimum temperatures (T_min), Lake Superior peak ice cover, and regional to continental-scale atmospheric winter pressure variability including the North American Dipole. The immense thermal inertia of Lake Superior underlies the unique connection between winter conditions and tree-ring Δ¹³C and δ¹⁸O …

Stable Isotopes Of Clay Minerals From Autoclave Tests Of Oil Sands: Implications For Clay Formation During Steaming Of Alberta Clearwater Oil Sands, Shaoneng He, Fred J. Longstaffe, Zhihong Zhou

Earth Sciences Publications

In an effort to evaluate mineral-water isotopic exchange during cyclic steam stimulation (CSS), solutions and<2 μm berthierine-dominated solids from the Clearwater Formation oil sands of Alberta, Canada were analyzed for stable isotope compositions before and after reaction in autoclaves for 1008 h at 250 °C. There was no significant change in solution δ¹⁸O and δ²H, which is consistent with the high water/mineral ratio used in the experiments. The solids showed a marked decrease in both δ¹⁸O and δ²H following the experiments. Pre-run solids have δ¹⁸O of +9.5 to +12.9‰and …

Understanding New Trends On Gold Mineralization At The Yellowknife City Gold Project, Northwest Territories, Using Synchrotron X-Ray Spectroscopy, Ramjay Jude L. Botor

Electronic Thesis and Dissertation Repository

The Yellowknife City Gold Project (YCGP) currently encompasses 780 sq. km of contiguous land north, south and east of the city of Yellowknife. The project lies in the prolific Archean north-south trending Yellowknife Greenstone Belt, a suite of mafic and felsic volcanics and greywacke turbidites overlying a gneissic basement. Exploration and drilling efforts have been focused along 70 km of strike length on the southern and northern extensions of the mineralized shear zones and quartz veins associated with the past-producing high-grade Con (6.1 Moz @ 16.1 g/t Au) and Giant (8.1 Moz @ 16.0 g/t Au) gold mines.

Synchrotron X-ray …

Characterization Of Kelyphite Rims: Relevance To Diamond Exploration, Mallory N.G. Metcalf

Electronic Thesis and Dissertation Repository

A detailed investigation into the mineralogy and chemistry of kelyphitic rims/veins on garnets was conducted using µXRD, EPMA and Raman spectroscopy for a suite of samples from economic and non-economic kimberlites in Canada and South Africa. Mineralogy demonstrates the influence of metasomatic fluids during the reactions which produced kelyphite in all localities and was used to propose P-T regions where kelyphite could have formed. Using chemical analyses of host garnets and the mineralogy obtained for kelyphite, modified chemical reactions representing Types 1 and 2 kelyphite are provided to describe kelyphite reactions in open systems. Elastically-strained secondary garnet is common in …

Emplacement Of The Foy, Hess And Pele Offset Dykes At The Sudbury Impact Structure, Canada, Eric A. Pilles

Electronic Thesis and Dissertation Repository

The 1.85 Ga Sudbury impact structure is the remnant of what is generally considered to have been an ~150–200 km diameter impact basin in central Ontario, Canada. The so-called Offset Dykes are impact melt dykes that are found concentrically around – and extending radially outward from – the Sudbury Igneous Complex (SIC), a ~3 km thick differentiated impact melt sheet. The dykes are typically composed of two main phases of granodiorite: an inclusion- and sulfide-rich granodiorite in the centre of the dyke, and an inclusion- and sulfide-poor granodiorite along the margins of the dyke. This study uses a combination of …

Inter- And Intra-Annual C And N Isotopic Variability Of C3 And C4 Grasses In A Temperate-Humid Dune Environment, Roshni R. Patel

Electronic Thesis and Dissertation Repository

Seasonal and annual variations in foliar δ¹³C and δ¹⁵N of a C₃ grass Ammophila breviligulata and a C₄ grass Calamovilfa longifolia from the sand dunes of Pinery Provincial Park in southern Ontario, Canada were investigated to assess isotopic variability at a single site within a temperate-humid climatic zone. This work quantifies seasonal δ¹³C and δ¹⁵N variation, tests for correlation of δ¹³C and δ¹⁵N with weather parameters, and evaluates the isotopic responses of these grasses to location within the dune system. Throughout the 2014 growing season, there …

Metallogenic Setting Of High-Grade Iron Ores, Mary River District, North Baffin Island, Nunavut, Meghan E. Macleod

Electronic Thesis and Dissertation Repository

Supracrustals of the 2.76-2.71 Ga Mary River Group form the northeastern segment of the Committee Bay Belt. Field mapping has determined that this succession is preserved in structural keels marginal to high-grade gneiss domes and is characterized by lower metasedimentary rocks and an upper BIF-komatiite-quartzite succession. Algoma-type BIF sited at the dome/keel boundary is host to bodies of high-grade iron ore, the largest being Deposit 1 which has an estimated reserve of 500 mt averaging 64 wt % Fe.

Field mapping, petrography, and EMPA indicates 3 main stages of ore formation. Stage 1 was characterized by the formation of the …