Geophysics and Seismology Commons^™

The Study Of Titan's Surface Using Impact Craters And Analogues, Jahnavi Shah

Electronic Thesis and Dissertation Repository

Titan, Saturn’s largest moon, is an icy world harbouring a subsurface water ocean, a substantial atmosphere, and a flowing liquid on its surface. These distinctive characteristics give rise to complex chemical reactions on Titan, and also render it akin to Earth in terms of its landforms and processes. This positions Titan as a key target for studying prebiotic chemistry. NASA's fourth New Frontiers mission, Dragonfly, is poised to explore Titan’s surface in the 2030s. Dragonfly’s primary study site will be Selk crater, a relatively fresh impact crater located in Titan’s equatorial sand seas. Impact craters serve as valuable markers for …

A Periglacial Landsystem Analysis In The Canadian High Arctic: A Tool For Planetary Geomorphology, Chimira Nicole Andres

Electronic Thesis and Dissertation Repository

Permafrost underlies 50% of Canada’s terrain and underlies 24% of the Earth’s total land area. It is a major driving force in the generation and evolution of patterned ground landforms such as polygons, stone circles, mud boils, and stripes, etc. that are seen on both the surface of the Earth and Mars, specifically in periglacial domains. The distribution of subsurface ice in these landforms (i.e. polygonal terrain) on Earth is a key constraint on past climate and process-form relationships in high arctic and periglacial regions. These landforms also have the potential of storing ice in the subsurface meaning that the …

Numerical Simulations Of Complex Crater Formation In Layered And Mixed Targets, Ryan Hopkins

Electronic Thesis and Dissertation Repository

Numerical simulations of hypervelocity impact events provide a unique method of analyzing the mechanics that govern impact crater formation. This thesis describes modifications that were made to the impact Simplified Arbitrary Lagrangian Eulerian (iSALE) shock-physics code in order to more accurately simulate meteorite impacts into layered target sequences and details several applications that were investigated using this improved strength model.

Meteorite impacts occur frequently in layered targets but resolving thin layers in the target sequence is computationally expensive and therefore not often considered in numerical simulations. To address this limitation iSALE was modified to include an anisotropic yield criterion and …

Impact Craters On Titan: Finalizing Titan's Crater Population, Joshua E. Hedgepeth

Electronic Thesis and Dissertation Repository

Titan is one of the most dynamic moons in the solar system. It is smaller than Earth and much colder, yet Titan is eerily similar to Earth, with rivers, rain, and seas, as well as sand seas that wrap around the equator. However, the rivers are made of hydrocarbons rather than water and the sand made of organics rather rock. We can use Titan’s impact craters to study how these processes modify the surface by comparing the craters depths, diameters and rim heights of Titan’s craters with fresh craters. Therefore, we have used the complete data set from NASA’s Cassini …

Petrophysical Investigations Of The Marathon Cu-Pge Deposit, Marathon, On, Hiruni Gunawardana

Electronic Thesis and Dissertation Repository

Drill core samples obtained from four mineralized zones of the Marathon Cu-PGE deposit in the Coldwell igneous complex have been investigated for their petrophysical characteristics. Remanent magnetization was used as a possible tool to reorient core samples but a drilling induced overprint magnetization dominated the record. Anisotropy of magnetic susceptibility was measured to provide a proxy for the petrofabric of samples obtained from oriented drill cores; a well-defined planar fabric was found to strike 177 and dip 25°W, with down-dip lineation, in excellent agreement with inferred magmatic flow direction based on 3D modeling of mineralized footwall troughs. Magnetite rich lithologies …

The Application Of Geophysical Inversion Techniques To The Nechalacho Rare Earth Element Deposit, Nt, Derek W. Kouhi

Electronic Thesis and Dissertation Repository

The Nechalacho deposit is a world-class rare earth element deposit located in the Thor Lake region approximately 100 kilometers southwest of Yellowknife, NT, Canada. Located within the Blatchford Lake Intrusion Complex, this deposit has the potential to be a large-scale economic asset due to its relatively shallow and sub-horizontal geometry. In this study, geophysical inversion techniques are used to model subsurface magnetic susceptibility and density in order to delineate the deposit. Isolated and joint inversion of both magnetic and gravity data provides similar models. Each inversion procedure delineates a shallow, sub-horizontal layer of high susceptibility and density in approximately the …

Climatic Cycles Recorded In Glacially Influenced Rhythmites Of The Gowganda Formation, Huronian Supergroup, Tim S. Howe, Patricia L. Corcoran, Fred Longstaffe, Elizabeth A. Webb, R Gerhard Pratt

Earth Sciences Publications

The Gowganda Formation of the 2.45–2.2 Ga Huronian Supergroup contains glacially-induced, varve-like rhythmites that potentially preserve a detailed record of climatic conditions during the Paleoproterozoic Era. Four rhythmic couplet thickness records were measured at two outcrops near Wharncliffe, Ontario for the purpose of time-series analysis. The couplets, which range from 1 to 32 mm thick, are composed of alternating layers of siltstone and claystone. Time-series analysis of the couplet thickness records using the MTM Toolkit of Mann and Lees (1996) consistently revealed periodicities in the range of 2.2–2.9 couplets per cycle, which is consistent with climatic cycles such as the …

Strength Study Of Zircon Under High Pressure, Ievgeniia Morozova

Electronic Thesis and Dissertation Repository

Zircon (ZrSiO₄) is a strong accessory mineral that can retain U, Th and Hf within its structure. This makes zircon an important material in geochemical and geochronological studies. In addition, the strong thermal shock resistance of zircon allows for dating the formations of melt and impact events and to separate shocked and potentially shocked country rocks. However, the deformation mechanism and microstructure behavior of zircon at high pressure is poorly understood. Therefore, this work aims to study the deformation and texture of zircon in situ at high pressure and room temperature, and also to examine the microstructure of …

Hydrogeological And Thermal Sustainability Of Geothermal Borehole Heat Exchangers, S. Emad Dehkordi

Electronic Thesis and Dissertation Repository

Assessment of the current approach taken by guidelines and design methods of vertical closed loop heat exchangers shows that often groundwater flow is either disregarded or is not methodically incorporated. The state of scientific research in this arena reveals that overlooking the groundwater flow in the design procedure may not always be a correct assumption. The significance of advective heat transport compared to conduction is defined by the groundwater flux or Darcy velocity which heavily depends on the hydraulic conductivity of the ground, followed by the hydraulic gradient which has a relatively limited range. A sensitivity analysis on ground and …