Physical Sciences and Mathematics Commons^™

Estimating Subsurface Anisotropy: Combining Waveform Tomography And Simulated Annealing, Michael Victor Afanasiev

Electronic Thesis and Dissertation Repository

Crosshole seismic tomography has been used by Vale to provide geophysical images of mineralized massive sulphides in the Eastern Deeps deposit at Voisey's Bay. High resolution seismic images are presented by applying acoustic waveform tomography to these data. In waveform tomography, an initial model is required which predicts the first arrival traveltimes to within a half-cycle of the lowest frequency in the data. Because seismic velocity anisotropy can be significant, the initial model must quantify the anisotropy, as well as the velocity, in order to meet the half-cycle criterion.

In our case study, difficulties were encountered in generating an accurate …

Stable Isotopes And Xrd Investigation Of Gold Mineralization At The Syenite-Hosted Young-Davidson Deposit, Matachewan, Ontario, Niloufar Naderi

Electronic Thesis and Dissertation Repository

The Young-Davidson mine is a syenite-hosted orogenic gold deposit at the western end of the Cadillac-Larder-Lake deformation zone in the southern Abitibi greenstone belt, Canada. This study utilized oxygen isotopes to assess the sources of the fluids and evaluate the role of magmatic and metamorphic fluids in gold mineralization. XRD analyses completed on whole-rock powder samples combined with petrography provides a better understanding of the distribution, timing, and nature of alteration patterns and their relationship to gold mineralization.

Temperatures calculated from mineral separates oxygen isotope thermometry indicate the fluids ranged from approximately 322 ± 25° to 431 ± 30°C. The …

Crystal Structure And Al/Si Cation Ordering In "Fassaite": A Combined Single Crystal, 27al And 29si Nmr Study, Monika M. Haring

Electronic Thesis and Dissertation Repository

Al-,Ti-rich diopside, referred to herein as fassaite, occurs in both terrestrial and extraterrestrial environments. The composition of fassaite, Ca(Mg,Al)(Si,Al)₂O₆, makes it ideal for Al/Si cation ordering studies. In this study, crystal XRD, ²⁷Al and 29Si MAS NMR as well as ²⁷Al 3QMAS NMR is used to study cation ordering in extraterrestrial fassaite from Allende CAIs and a terrestrial analogue from Fassa Valley Italy. From ²⁷Al and ²⁹Si spectroscopy, fassaite from Allende CAIs is found to have more local Al/Si cation ordering than terrestrial Fassaite. Both terrestrial and extraterrestrial have C2/c …

Arctic Cold Spring Mineralogy As An Indicator Of Spring Deposits, Water, And Habitable Environments On Mars, Melissa M. Battler

Electronic Thesis and Dissertation Repository

Springs exist in many terrestrial settings and have supported microbial communities throughout Earth’s history. There is mounting evidence for spring deposits on Mars from Noachian age to present, implying that water may be circulating in Mars’ subsurface despite current cold, arid conditions. Current datasets for most of Mars are limited to mineralogy via orbital spectroscopy and geomorphology from visual imagery and laser altimetry. Much is known about terrestrial spring morphology, but few springs exist in Mars analogue settings, and of those, few have been investigated for mineralogy. This study reports on two sets of cold spring sites in the Canadian …

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu

Electronic Thesis and Dissertation Repository

This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and …

Strength, Elasticity And Phase Transition Study On Nacl And Mgo-Nacl Mixture To Mantle Pressures, Zhongying Mi

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Rheological properties of the Earth control most of the important geological processes, such as mantle convection, plate tectonics, earthquakes and nature of thermal evolution. Most parts of the Earth consist of multi-phase polycrystalline aggregates with various composition and compressibility. Therefore, deformation studies on multi-phase materials are important to understand the rheological properties and convection of the Earth. NaCl and MgO with large contrast in elastic properties are excellent analogue materials for modelling the Earth that is generally made of both strong and weak materials. In addition, NaCl and MgO are widely used as pressure transmitting medium and pressure calibration standard …

Characterization Of Novel Ichnofossils In Meteorite Impact Glass From The Ries Impact Structure, Germany, Haley M. Sapers

Electronic Thesis and Dissertation Repository

The initial catastrophic biological effects of hypervelocity impacts are well established. However, a growing body of evidence suggests that meteorite impact events have beneficial effects for microbial life. This, in turn, has led many to suggest that impact craters may have been important habitats for life on early Earth. Any large meteorite impact into a water-rich target on a solid planetary body has the potential to generate hydrothermal systems. Impact-generated hydrothermal systems expand the potential environments for microbial colonization to environments without endogenous volcanic heat sources to drive hydrothermal activity. Examination of impact glass from the Ries impact structure, Germany, …

Strategies For Visco-Acoustic Waveform Inversion In The Laplace-Fourier Domain, With Application To The Nankai Subduction Zone, Rie Kamei

Electronic Thesis and Dissertation Repository

Waveform inversion is a non-linear and ill-posed inverse problem, with the objective of utilizing the full information content of recorded seismic waveforms. A Laplace-Fourier domain implementation allows a natural `multiscale' approach that mitigates the non-linearity and ill-posedness by inverting low-frequency, early arrival data in the initial stages of inversion. High-frequency components, and late arrivals are incorporated at a later stage. This allows the development of robust inversion strategies capable of handling large wide-angle crustal surveys, leading to reliable, high-resolution velocity and attenuation models of crustal structures. I apply waveform inversion to extract a P-wave velocity model of the active megasplay …

Evaluation Of Jarosite As A Biosignature: A Comparison Of Biogenic And Synthetic Jarosites, Liane Loiselle

Electronic Thesis and Dissertation Repository

The detection of jarosite (K)Fe₃(SO₄)₂OH₆ on Mars has been interpreted as mineralogical evidence of acid-sulfate aqueous processes, including putative evidence of biological activity. Terrestrial habitats where acidic conditions occur are environments where microbiota thrive and generate biological signatures. A biotic and synthetic jarosite were produced to evaluate the ability and effectiveness of existing analytical methods to identify biosignatures in targeted geological materials. Using a comprehensive suite of microscopic (light microscopy, SEM and TEM), mineralogical (XRD), spectroscopic (IR, LIBS, Mössbauer, UV-Vis-NIR, and Raman) and mass spectrometry (ToF-SIMS) techniques, the two jarosites were found to …

Evolution Of The Late Ordovician Plaesiomyid Brachiopod Lineage In Laurentia, Colin D. Sproat

Electronic Thesis and Dissertation Repository

During the Late Ordovician, a transgression flooded much of Laurentia. The fauna of these intracratonic basins became differentiated from the fauna of the pericratonic shelves and platforms, typically displaying gigantism and coarser shell ornamentation. In this study, 509 specimens from 11 species of the Plaesiomyidae brachiopod family from the Katian and Hirnantian were measured, of which 198 included in principal component analysis to quantify morphological changes over this interval. Three trends were revealed: 1) increasing globosity and dorsal convexity from the early to late Katian, 2) coarser, but fewer ribs on species from the paleoequatorial intracratonic seas compared to species …

Stratigraphy And Sedimentology Of The Late Cretaceous (Coniacian) Muskiki And Marshybank Members, Southern Alberta And Northwestern Montana, Meriem Grifi

Electronic Thesis and Dissertation Repository

A high-resolution allostratigraphic study of the Coniacian Muskiki and Marshybank members of the Wapiabi Formation in southern Alberta revealed a southwest thickening wedge of mudstone-dominated strata that was deposited on a shallow storm-dominated shelf. Well-log correlations and biostratigraphy show that the Muskiki Member forms the bulk of the succession; the Marshybank Member is thin or absent in the subsurface. The lower and middle units of the Muskiki Member display regional subsidence patterns consistent with thrust sheet loading in the Cordillera. The upper unit comprises a linear trough filled by southeastward-accreting clinothems. The northeast boundary of the clinoform package corresponds with …

Investigation Of Hydrothermal Alteration Processes In The Troodos Ophiolite And The Abitibi Greenstone Belt, Tamara P. Sredojevic

Electronic Thesis and Dissertation Repository

Hydrothermal alteration is an important and ubiquitous process between rocks in the Earth’s crust and seawater. To gain more understanding of such processes, two localities are investigated here: the Troodos Ophiolite Complex of Cyprus and the syenitic rocks associated with gold mineralization at the Upper Canada property, Kirkland Lake, Ontario. This thesis reports unique effects of hydrothermal activity. The Troodos Ophiolite samples consist of sheeted diabase dykes, gabbroic and ultramafic rocks in the CY-4 drill hole. The oxygen isotopic signature of these rocks indicates that alteration temperatures increased downhole and channeling of low-temperature fluids occurs at the dyke – gabbro …

Technique Design To Increase In-Situ Electrical Connections In A Cubic Anvil Press, Marie April Burford

Electronic Thesis and Dissertation Repository

An experimental technique designed to increase in-situ electrical connections in a cubic anvil press has been developed. Two encompassing cell designs (extruded gasket and pre-formed gasket) were tested with several electrical barrier methods: PVD coatings, G-10/FR-4 and Canvas Electrical (C. E.) phenolic, Teflon and Al ceramic tubing.

Many variations of techniques were attempted and each (n)^th attempt was founded on the experience from/observation of the results obtained with the (n-1)^thtechnique variation. Eighteen pressure cell configurations were designed and tested. The cells with self-extruded gaskets were unsuccessful due to the destructive nature of the extruding gaskets on the …

An Investigation Into Earthquake Ground Motion Characteristics In Japan With Emphasis On The 2011 M9.0 Tohoku Earthquake, Hadi Ghofrani

Electronic Thesis and Dissertation Repository

In this integrated study, ground-motion characteristics of one of the most devastating earthquakes in history, the 11^th March 2011 Tohoku-oki earthquake (moment magnitude (M) 9.0), are investigated. The investigation centers on developing empirical and simulated-based ground-motion prediction models for this earthquake. These models allow prediction of expected ground motions from large interface (mega-thrust) earthquakes and estimation of their variability due to variability in input parameters, specifically source characteristics (e.g. slip distributions), propagation path, and site effects.

This research work can be divided into two main parts. In the first part, the influence of regional geologic structure, in …

Late Archean Oceans: A Laboratory Model Of Oxygen Oases, Maija J. Raudsepp

Electronic Thesis and Dissertation Repository

A cyanobacterial mat, including associated aerobic and anaerobic heterotrophs, was grown in an airtight chamber to simulate the formation of an oxygen oasis in two different Archean-like environments. In the first experiment, methane added to the ecosystem was rapidly oxidized and then O_2(g) increased to 10%. Photosynthesis resulted in a pH of 9.5 and the precipitation of magnesium-manganese carbonates within the mat. In the second experiment, daily additions of ferrous iron were rapidly oxidized, resulting in ferric hydroxide encrusted mat. The growth of cyanobacteria and iron reducing bacteria resulted in an active redox cycle between ferrous and ferric iron. …

Planetary Materials Science And Astrobiology, Matthew R. M. Izawa

Electronic Thesis and Dissertation Repository

Planetary materials contain signatures of diverse processes in their mineralogy, chemistry, textures and assemblages. The record contained in planetary materials reflects the complex and commonly overprinting relationships between many processes. Discerning what mechanisms have operated to produce the rocks we observe requires first a careful characterization of various properties. These include the chemical and structural makeup of the rocks (that is, the mineralogy and mineral chemistry), the textural relations within and between rocks (petrology) Therefore, the key to how the studies here hold together is also in the methodology and guiding philosophy: understanding what is there (what atoms and how …

Architecture And Stratigraphy Of The Lower Silurian Guelph Formation, Lockport Group, Southern Ontario And Michigan, Candace Brintnell

Electronic Thesis and Dissertation Repository

The Lower Silurian Lockport Group in Ontario and Michigan comprises, in ascending order: Gasport, Goat Island, Eramosa, and Guelph formations. Guelph facies architecture reveals deposition on an underlying carbonate ramp of Eramosa and/or Goat Island carbonates that dipped towards the Appalachian Basin. Temporally, Guelph facies reflect initial open marine transgressive phases that become increasingly restricted marine and karstic upward. Spatially, the facies display the most restricted marine and karstic fabrics in the central portion of the ‘Michigan Basin’ and are most open marine to the east. Newly acquired regional data supports the re-interpretation of the classic Guelph-pinnacle reef models as …

Deep Crustal Evolution Of The Western Churchill Province, Nunavut, Canada: Isotopic (U-Pb, O), Trace Element And Micro-Structural Analysis Of Zircon From Lower Crustal Xenoliths, Duane C. Petts

Electronic Thesis and Dissertation Repository

Zircon from lower crustal xenoliths can preserve unique crustal formation records of unexplored levels of the lithosphere. The first such records for the western Churchill province (Nunavut, Canada) are presented here. Zircon SIMS U-Pb geochronology and oxygen isotope analysis were conducted on kimberlite-hosted granulite-facies xenoliths: four metabasites (#9864; #9865; #9866; #9870) from the Rankin Inlet region, and five metabasites (#10162; #10163; #10167; #10169; #10179) and three metatonalite/anorthosites (#10158; #10164; #10168) from the Repulse Bay region. For the Rankin Inlet suite, oscillatory planar zoned, igneous cores from metabolite xenolith #9865 record dates between ca. 2.9–2.6 Ga, whereas complex to radial-sector zoned …

Sedimentology And Allostratigraphy Of The Cardium Formation (Turonian-Coniacian) In Southern Alberta, And Equivalent Strata In Northern Montana, Joel Shank

Electronic Thesis and Dissertation Repository

The Turonian-Coniacian Cardium Formation of southern Alberta consists of marine sandstone and mudstone, deposited in a foreland basin over ~2.3 m.y. The formation thins from 150 m in the western foredeep to 50 m 350 km to the east. Correlation of 10 regional flooding surfaces in >1200 well logs and 25 outcrops provides an allostratigraphic framework. Mapping of two previously-unrecognized erosion surfaces (E5.2 and E5.5) reveals additional complexity within sandstone of the Raven River Member.

Facies successions coarsen upwards from thinly-bedded and bioturbated mudstone, to heterolithic facies (either bioturbated or bedded), to clean sandstone. Where conglomerate unconformably overlies this succession, …

Bacterial Communities And Their Influence On The Formation And Development Of Potholes In Sandstone Surfaces Of The Semi-Arid Colorado Plateau, Kebbi A. Hughes

Electronic Thesis and Dissertation Repository

Potholes are weathering features, of various sizes and shapes, which are found in exposed rock surfaces that lack vegetative and soil cover. Biofilms associated with the ephemeral aquatic pothole environments of the Colorado Plateau were examined as initial and intermediate stages of colonisation of arid, oligotrophic rock surfaces.

Imaging of the interface between pothole biofilms and their host rock revealed features of biological weathering; chiefly, the breakdown of silicate minerals and precipitation of clay and carbonate minerals. High pH measured in pothole water reflected deposition of secondary carbonate minerals at some locations and indicated the development of high pH microenvironments …

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 …

The Weathering Of Platinum From Nuggets And Platinum Immobilisation By Cupriavidus Metallidurans, Sean Gordon Campbell

Electronic Thesis and Dissertation Repository

Two studies were conducted to investigate the biogeochemistry of platinum. In the first project, platinum nuggets were examined to evaluate mineral dissolution-precipitation processes occurring at the nugget-‘soil solution’ interface. The presence of dissolution ‘pits’, cavities, and striations as well as acicular, iron oxides coating the grain surface evidence that this interface is an important site of mechanical and chemical weathering. Element mapping revealed that structural and chemical signatures can be linked to morphological features on the grain surface. In the second study, the soil bacterium Cupriavidus metallidurans was reacted with aqueous platinum chloride and rapidly immobilised platinum. XANES/EXAFS analysis of …

Applicability Of The Eshelby Formalism To Viscous Power-Law Materials: A Numerical Validation, Zhenyu Zhong

Electronic Thesis and Dissertation Repository

Fabric is important for the interpretation of tectonic evolutions. In the process of extrapolating small-scale fabric to tectonics, modeling frameworks are needed. Neither the early kinematic models nor the contemporary computational geodynamics are able to capture the complexities of the fabric development in natural deformation systems. Eshelby proposed a formalism in micro-mechanics, and it is now well understood that this formalism works well for the linear viscous deformations. However, given that most of the natural rocks are power-law materials, the Eshelby Formalism cannot be directly applied to geological problems. This problem was largely solved when Lebensohn and Tom (1993, Acta …

An Investigation Of Deformation Structures And Their Tectonic Significance Across The Grenville Front Tectonic Zone In The Vicinity Of Sudbury, Ontario, Canada, Changcheng Li

Electronic Thesis and Dissertation Repository

The Grenville Front Tectonic Zone (GFTZ) is a polyphase deformation belt in the northwest of the Grenville Province which was shaped in the continent-continent-collision-induced Grenvillian Orogeny.

This thesis focuses on the evolution of deformation fabrics in the GFTZ between the Sudbury Basin and French River in Ontario, Canada. Geological mapping using a new digital mapping system was conducted within this segment of the GFTZ, in its northwest vicinity in the Southern Province, and in its southeast vicinity in the Grenville Province. The new digital mapping system includes a personal digital assistant equipped with an internal GPS and a mobile GIS …

Late Quaternary Histories Of Lakes Huron And Michigan: A Stable Isotope Investigation Of Sediment Cores And Modern Biogenic Carbonates, Rebecca A. Macdonald

Electronic Thesis and Dissertation Repository

Late Quaternary histories are investigated here for sediment cores from Lakes Huron and Michigan, using the oxygen- and carbon-isotope compositions of biogenic carbonates and the oxygen- and hydrogen-isotope compositions of porewater. Age models for these cores are based on sedimentological information, and where possible, radiocarbon and pollen dates. The Michigan Basin cores provide a thick record of the late Pleistocene, whereas the Huron Basin cores primarily record Holocene deposition. Taken together, the histories recorded in biogenic carbonates from these sediments provide a clear account of lakewater isotopic changes – and their significance – over much of the history of the …

Reconstructing Fire Severity From The Oxygen-Isotope Compositions Of Plant Char, Michael W. Hamilton

Electronic Thesis and Dissertation Repository

This study assessed whether variations in the oxygen-isotope compositions of char formed from biomass burning could be related to burning severity. Ground samples of oak (Quercus alba), pine (Pinus resinosa), and grass (Andropogon gerardii) were charred for 5 and 30 minutes at constant temperatures between 200 and 900°C under oxygenated versus anaerobic conditions. Char oxygen-isotope values became progressively depleted of ¹⁸O by up to 25.8‰ for wood and 16.5‰ for grass as temperature, duration of burning, and amount of oxygen increased. The primary reason for the decrease in oxygen-isotope values is the loss …

Studies Of Aftershock Sequences Of Large Subduction Zone Earthquakes, Armick Ivanian

Electronic Thesis and Dissertation Repository

Amongst the different types of earthquakes, it is observed that the mega-thrust earthquakes, which occur in subduction zones, are the most devastating. The aftershock sequences following the mega-thrust earthquakes can also increase the level of seismic hazard, even in remote areas away from the mainshock fault zone. This thesis examines the statistical parameters of aftershock sequences of large subduction zone earthquakes that have occurred in the western and eastern Pacific Ocean. These parameters are vital for seismic hazard assessment of regions located near subduction zones. The results show that, on average, the Gutenberg-Richter exponent—the b-value—is markedly higher in the …

A Geobiological Investigation Of The Mazon Creek Concretions Of Northeastern Illinois, Mechanisms Of Formation And Diagenesis, Andrea S. Fernandes

Electronic Thesis and Dissertation Repository

Siderite concretions from the mid-Pennsylvanian Francis Creek Shale of the Mazon Creek area, in northeastern Illinois, contain exceptionally preserved soft-tissue fossils. Scanning electron microscopy, energy dispersive spectroscopy, time of flight-secondary ion mass spectrometry and micro-x-ray diffraction on polychaete worm, jellyfish and holothurian samples highlighted detrital clay and quartz grains in siderite cement. The worm and jellyfish are pyritised and surrounded by pyrite halos, whereas the holothurian is preserved as a weathered impression. Specimens possessed either microbial textures or framboidal pyrite, in carbon-enriched zones. The carbon-enriched zones contained organic compounds, indicating that extensive degradation associated with high temperature diagenesis did not …

Relationships Between Earthquake Ground Motions And Modified Mercalli Intensity, Andrea Sweny

Electronic Thesis and Dissertation Repository

With widespread Internet use, web-based earthquake reports are a valuable source of felt intensitydata with broad geographical coverage. Paired with ground motion data, Internet surveys like theUSGS Did You Feel It? (DYFI) website can be used to derive relationships between ground motionparameters and Modified Mercalli Intensity (MMI). These are particularly important for regionswith sparse seismographic coverage where the quality and density of intensity data may be superiorto ground motion data. MMI-ground motion relationships are also needed to infer ground motionsof historical earthquakes.

Using well-documented earthquakes in across North America, we analyze correlations betweenfelt intensity and ground motions, including peak ground …