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Articles 31 - 60 of 178

Full-Text Articles in Geology

Organic Geochemistry, Organic Petrography And Basin Modelling Of The Upper Cretaceous Second White Specks And Upper Belle Fourche Alloformations In The Western Canada Foreland Basin, Mailyng Angelica Aviles Jun 2021

Organic Geochemistry, Organic Petrography And Basin Modelling Of The Upper Cretaceous Second White Specks And Upper Belle Fourche Alloformations In The Western Canada Foreland Basin, Mailyng Angelica Aviles

Electronic Thesis and Dissertation Repository

The Second White Specks is an unconventional shale play in the Western Canada Foreland Basin, endowed with over 450 billion barrels of light oil in place. Inconsistent production performance, however, has hindered its economic viability as a resource play. One potential explanation for erratic production behavior, on local and regional scales, is heterogeneous distribution of retained oil charge in the source rock. This study focuses on the analysis of geochemical properties and thermal history of the organic matter to assess lateral variability in generated hydrocarbon in the Second White Specks.

The methodology comprised characterization of the organic matter integrating organic …


An Assessment Of The Spatial And Temporal Distribution Of Microplastics In Surface And Subsurface Sediment Of Lake Huron, North America, Sara L. Belontz Apr 2021

An Assessment Of The Spatial And Temporal Distribution Of Microplastics In Surface And Subsurface Sediment Of Lake Huron, North America, Sara L. Belontz

Electronic Thesis and Dissertation Repository

The awareness of and the data on the prevalence of microplastic (plastic particles <5mm) pollution in freshwater environments is rapidly increasing, as low-degrading polymers are being detected in various environmental matrices of the Laurentian Great Lakes. However, the accumulation, distribution and deposition of microplastics in offshore depositional environments of the Great Lakes, and particularly Lake Huron, is relatively unknown. In this study, benthic sediment from various Lake Huron waterbodies (main basin, Georgian Bay, the North Channel, and Saginaw Bay) was quantified for microplastic particles (fibres, fragments, films, and beads). The North Channel contained the greatest microplastic abundances, averaging 47,398 particles per kg-1 dry weight sediment (p kg-1 dw), followed by Georgian Bay (21,390 p kg-1 dw), the main basin (15,910 p kg-1 dw) and Saginaw Bay (1,592 p kg-1 dw). The results suggest that microplastic abundances in offshore settings are positively correlated with increasing water depth (p=0.004) and are controlled by lake bottom geomorphology. Hydrodynamic processes are a prevailing force driving microplastic dispersion and deposition into the offshore, in contrast to source-based drivers closer to the shoreline. Sediment cores were examined from …


Geological, Mineralogical And Geochemical Process Controls On Ni Tenor Variations In The Metasedimentary-Hosted Thompson 1d Orebody At Vale’S Thompson Mine (T3), Northern Manitoba, Canada, Povilas G. Grigutis Apr 2021

Geological, Mineralogical And Geochemical Process Controls On Ni Tenor Variations In The Metasedimentary-Hosted Thompson 1d Orebody At Vale’S Thompson Mine (T3), Northern Manitoba, Canada, Povilas G. Grigutis

Electronic Thesis and Dissertation Repository

The Proterozoic Thompson Nickel Belt (TNB) contains rift-related mafic-ultramafic igneous rocks, in a collisional belt at the NW margin of the Archean Superior province in Northern Manitoba, Canada. The TNB hosts world class Ni-Cu-(PGE) mineralization, that has undergone polyphase deformation (D1 – D4) and upper amphibolite to lower granulite facies metamorphism, up to ~750ºC and 7.5 kbars (Lightfoot et al., 2017). Komatiitic magmas (1880 ± 5 Ma; Hulbert et al., 2005) fertile in Ni & PGE elements intruded Ospwagan Group metasedimentary sequences and through sulfur assimilation and segregation produced primary magmatic sulfides (Lesher and Burnham, 2001).

The …


An Investigation On Flow Field Partitioning Related To The Rheological Heterogeneities And Its Application To Geological Examples, Ankit Bhandari Mar 2021

An Investigation On Flow Field Partitioning Related To The Rheological Heterogeneities And Its Application To Geological Examples, Ankit Bhandari

Electronic Thesis and Dissertation Repository

Earth’s lithosphere is heterogeneous and composed of rheologically distinct elements at various scales of observations. This causes the flow of rocks to vary with space and time, which may influence the formation of various kinds of geological rock records. This thesis provides quantitative solutions to some first-order problems in structural geology regarding this heterogeneous flow variation and thereby the development of various geological rock records at different scales of observations.

Pressure in a rheologically heterogeneous element may deviate from its ambient value and if significant, may influence the metamorphic assemblages. This might cause problems in the routine use of geothermobarometry-based …


Plastic Debris In The Laurentian Great Lakes System, North America: Analysis Of Types, Abundances, And Sources, Ian A. Arturo Feb 2021

Plastic Debris In The Laurentian Great Lakes System, North America: Analysis Of Types, Abundances, And Sources, Ian A. Arturo

Electronic Thesis and Dissertation Repository

Understanding plastic pollution in the Laurentian Great Lakes system requires investigation of all plastic debris sizes and categories. Visible polymeric debris (VPD) mainly characterize shorelines, and microplastics (MPs;mm) are found in benthic and beach sediment. Field sampling of VPD from all five Great Lakes, visual and chemical identification of VPD types, and implementation of a matrix scoring technique (MST) indicate that plastic industries, urban areas, and shoreline recreation are major sources of VPD. Sampling for MPs in the St. Clair system, followed by preliminary density separation, and microscopy, suggest that wastewater treatment plants are a major source. This work is …


Hydrothermal Alteration Footprint Of The Monument Bay Project, Manitoba, Canada, Juliana Casali Dec 2020

Hydrothermal Alteration Footprint Of The Monument Bay Project, Manitoba, Canada, Juliana Casali

Electronic Thesis and Dissertation Repository

The Monument Bay (MB) project is a greenstone hosted gold deposit, located in NE Manitoba. Previous studies show significant gold grades in the area. This research aims to characterize and delineate the mineralogical and geochemical characteristics of the hydrothermal footprint and mineralization of MB. Combined synchrotron X-ray fluorescence, synchrotron X-ray diffraction, petrography, and electron microprobe techniques were used to support this study. Results indicate sericite and carbonate are the main hydrothermal alteration minerals with homogeneity in their mineralogical, textural, and geochemical characteristics across the deposit. Also, a strong relationship between Au, sericite alteration, and arsenopyrite grains is observed associating the …


Geometallurgy And Gold Mineralization Of The Monument Bay Project, Stull Lake Greenstone Belt, Manitoba, Canada, Chunyi Hao Dec 2020

Geometallurgy And Gold Mineralization Of The Monument Bay Project, Stull Lake Greenstone Belt, Manitoba, Canada, Chunyi Hao

Electronic Thesis and Dissertation Repository

The Monument Bay Project is located in the Archean Stull Lake Greenstone Belt, in Northern Manitoba, Canada. This thesis focuses on the geometallurgy and gold mineralization of the Monument Bay Deposit in order to better understand the multiple gold mineralizing events and provide a pathfinder to gold mineralization. Traditional microscopy is used in combination with geochemical and mineralogical analytical techniques (Electron Probe Microanalysis (EPMA) and Energy-dispersive X-ray Spectroscopy (EDS)/(WDS) element map) and synchrotron geochemical techniques (synchrotron X-ray Diffraction (SR-XRD), synchrotron micro X-ray fluorescence (SR-µXRF) mapping, X-ray Absorption Near-edge Structure (XANES) Spectroscopy). Metallic gold (Au0) exists as free gold …


Impact Of Interlayer Cation Composition And Strongly Bound Water On Smectite ẟ²H, As Determined By A Modified Tcea Method, Nadine J. Kanik Nov 2020

Impact Of Interlayer Cation Composition And Strongly Bound Water On Smectite ẟ²H, As Determined By A Modified Tcea Method, Nadine J. Kanik

Electronic Thesis and Dissertation Repository

Interlayer cation composition and cation hydration enthalpy can potentially affect the excess hydrogen-yield and δ2H of smectitic clays. Complexities arise from condensed atmospheric water adsorbed on the clay, as it constitutes a potential additional source of hydrogen when attempting to measure the δ2H of structural OH groups. To approach this problem, the δ2H of different cation-saturated, dried forms of six Clay Minerals Society Source Clay smectites were measured. A modified sample drying and on-line High-Temperature-Conversion-Elemental-Analysis (TCEA) Continuous-Flow-Isotope-Ratio-Mass-Spectrometry protocol, facilitated isotopic measurements. A stronger interlayer cation hydration enthalpy (Ca2+>Na+>K+), …


Clay Mineral Characterization And Production In Impact Settings: A Case Study On The Chicxulub Impact Structure, Mexico, Sarah L. Simpson Oct 2020

Clay Mineral Characterization And Production In Impact Settings: A Case Study On The Chicxulub Impact Structure, Mexico, Sarah L. Simpson

Electronic Thesis and Dissertation Repository

Impact cratering is the most ubiquitous geologic process shaping the surface of solid bodies in our Solar System. Despite their deleterious effects, impacts have the potential to initiate transient hydrothermal systems, making them attractive targets in the search for water and extraterrestrial life. The relatively low temperature nature of these environments and poor preservation state of craters on Earth leads to difficulties in determining the provenance of many alteration phases, particularly clay minerals. This becomes especially problematic on other clay-rich planetary bodies (e.g., Mars) where limited geologic information can lead to ambiguous and/or inaccurate interpretations. This thesis presents a case …


Hargraves Crater Ejecta And Implications For Impact Processes, Leah E. Sacks Oct 2020

Hargraves Crater Ejecta And Implications For Impact Processes, Leah E. Sacks

Electronic Thesis and Dissertation Repository

Impact craters and their ejecta deposits offer insights into the structure and composition of planet crusts. Hargraves Crater, Mars, demonstrates an unusual balance of exposure and preservation in its ejecta. Analysing its morphologic, morphometric, thermophysical, and stratigraphic characteristics, we interpret two predominant units: an underlying ballistic lithic breccia and an overlying impact melt-bearing deposit. The lower unit is a lithic breccia composed of sub-angular, unsorted clasts (~10-12 m mean diameter), while the overlying unit is a smooth, dark toned, smaller clast-bearing (~1 m diameter at image resolution) impact melt-bearing unit with polygonal fracturing. There appears to be a sharp contact …


A Periglacial Landsystem Analysis In The Canadian High Arctic: A Tool For Planetary Geomorphology, Chimira Nicole Andres Oct 2020

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 …


Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak Oct 2020

Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak

Earth Sciences Publications

The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a …


Stable Carbon And Oxygen Isotope Investigation Of Pleistocene Growing-Season Paleoclimate Using Tree-Ring Cellulose From The Missinaibi Formation, Adam Creek, James Bay Lowland, Canada, Jumin Lee Aug 2020

Stable Carbon And Oxygen Isotope Investigation Of Pleistocene Growing-Season Paleoclimate Using Tree-Ring Cellulose From The Missinaibi Formation, Adam Creek, James Bay Lowland, Canada, Jumin Lee

Electronic Thesis and Dissertation Repository

The isotopic compositions of cellulose in tree rings provide a record of seasonal and annual climatic conditions such as precipitation and temperature. We analyzed stable isotopes of carbon (δ13Ccellulose) and oxygen (δ18Ocellulose) in early-wood and late-wood of five conifer sub-fossil wood samples from the Missinaibi Formation, which likely grew during the peak of Marine Isotope Substage (MIS) 5a (~82 kya) at Adam Creek, Ontario. There was no systematic difference between early-wood and late-wood for either δ13Ccellulose or δ18Ocellulose, suggesting similar climatic conditions throughout …


Impact Melt-Bearing Deposits Around Martian Craters, William A. Yingling Aug 2020

Impact Melt-Bearing Deposits Around Martian Craters, William A. Yingling

Electronic Thesis and Dissertation Repository

In this work, we investigate impact melt emplacement around Martian craters. We compare our results to melt emplacement processes found on Venus, the Moon, and Mercury. We tentatively find Martian melt emplacement more closely resembles Venusian emplacement, rather than lunar emplacement. This suggests Martian melt emplacement likely takes place during the excavation stage where impactor momentum is imparted to the melt. Mercury and Mars have amongst the highest and lowest average impact velocities, respectively, of terrestrial bodies in the Solar System, but a significant difference in emplacement is not observed. This suggests impact velocity may not have as large an …


Determining Geological Controls On Nutrient Availability At Different Depths In The Soils Of The Pelee Island Winery, Lindsay M. Blythe Jun 2020

Determining Geological Controls On Nutrient Availability At Different Depths In The Soils Of The Pelee Island Winery, Lindsay M. Blythe

Electronic Thesis and Dissertation Repository

Terroir describes a sense of place that can give a unique flavour to wines grown in different environments. We explored the role of soil in the terroir at Canada’s most southern vineyard, Pelee Island Winery. This study examined the abundance of major nutrients, trace and rare earth elements of minerals and plant extractable nutrients from 19 soils across the vineyard to a depth of 2 m. We found that bedrock does not influence the element content of Pelee Island soils, the parent materials of the soils are tills and there are geochemical, mineralogical and grain size differences between the two …


The Relationship Between Visible Gold And Arsenopyrite At The Orenada Zone 4 Deposit, Val D'Or, Quebec, Cassandra Powell Jun 2020

The Relationship Between Visible Gold And Arsenopyrite At The Orenada Zone 4 Deposit, Val D'Or, Quebec, Cassandra Powell

Electronic Thesis and Dissertation Repository

The Orenada Zone 4 deposit is an Archean orogenic gold deposit situated southeast of Val d’Or, Québec in the southeastern Abitibi Greenstone Belt. It is located directly within the Cadillac-Larder-Lake Deformation Zone. Mineralization is hosted within a volcanoclastic horizon of the Cadillac Group where two distinct facies were defined. Both facies underwent a pervasive sericite-chlorite-carbonate±albite alteration assemblage that predates gold mineralization. Gold is associated with two generation of auriferous quartz-carbonate-tourmaline veins and within fractures of corroded arsenopyrite grains, located proximal to the vein walls. A LA-ICP-MS study determined that neither textural type of arsenopyrite displayed refractory gold. Therefore, gold was …


Impact-Generated Dykes And Shocked Carbonates From The Tunnunik And Haughton Impact Structures, Canadian High Arctic, Jennifer D. Newman Apr 2020

Impact-Generated Dykes And Shocked Carbonates From The Tunnunik And Haughton Impact Structures, Canadian High Arctic, Jennifer D. Newman

Electronic Thesis and Dissertation Repository

The Canadian High Arctic contains two impact structures created by hypervelocity impact events in carbonate-rich target rocks. The remote locations of the Tunnunik and Haughton impact structures means that there are aspects of these impact structures which have yet to be fully investigated. This study characterizes the range of impact-generated dykes exposed from both impact structures which include lithic breccias, impact melt-bearing breccias, and impact melt rocks. Breccias may include silicate impact glass fragments and evidence for carbonate melt. Impact melt rocks from the Haughton impact structure contain the rare terrestrial mineral moissanite. This is only the third reported occurrence …


Characterization Of Impact Melt Rocks And Hydrothermal Mineralization At The Haughton Impact Structure, Devon Island, Canada: An Investigation Of Impacts Into Carbonate Targets, Cassandra L. Marion Apr 2020

Characterization Of Impact Melt Rocks And Hydrothermal Mineralization At The Haughton Impact Structure, Devon Island, Canada: An Investigation Of Impacts Into Carbonate Targets, Cassandra L. Marion

Electronic Thesis and Dissertation Repository

Impact cratering is a fundamental and ubiquitous geological process on all solid planetary bodies in our solar system. Impacts into carbonate-rich sedimentary target rocks on Earth are still poorly understood. The fate of carbonates during impact, in particular whether they undergo melting or decomposition, is actively debated. The dominant process is significant as decomposition would cause severe climatic effects due to release of large amounts of carbon dioxide into the atmosphere. At the root of the problem is the difficulty to distinguish and characterize the genesis of the variety of impactite carbonates produced. The Haughton impact structure in the Canadian …


Characterization Of Impactite Clay Minerals With Implications For Mars Geologic Context And Mars Sample Return, Christy M. Caudill Apr 2020

Characterization Of Impactite Clay Minerals With Implications For Mars Geologic Context And Mars Sample Return, Christy M. Caudill

Electronic Thesis and Dissertation Repository

Geological processes, including impact cratering, are fundamental throughout rocky bodies in the solar system. Studies of terrestrial impact structures, like the Ries impact structure, Germany, have informed on impact cratering processes – e.g., early hot, hydrous degassing, autometamorphism, and recrystallization/devitrification of impact glass – and products – e.g., impact melt rocks and breccias comprised of clay minerals. Yet, clay minerals of authigenic impact origin remain understudied and their formation processes poorly-understood. This thesis details the characterization of impact-generated clay minerals at Ries, showing that compositionally diverse, abundant Al/Fe/Mg smectite clays formed through these processes in thin melt-bearing breccia deposits of …


Paleoproductivity Of Late Holocene Lake Huron, Jamal Khaled Nigim Mar 2020

Paleoproductivity Of Late Holocene Lake Huron, Jamal Khaled Nigim

Electronic Thesis and Dissertation Repository

The paleolimnology of North America’s Lake Huron is described using lead-210 dating, mineralogy, magnetic susceptibility, total organic carbon (TOC), total nitrogen (TN), carbon:nitrogen (C/N) ratio, grain size, and the δ13COM and δ15NTN of organic matter. Sediment cores from Lake Huron’s 6 depositional basins and Georgian Bay span the Medieval Warm Period, Little Ice Age, and Canadian-European settlement. The main organic matter source is lacustrine algae, as indicated by δ13COM, δ15NTN and C/N. Prior to the 19th century, primary production changes are reflected only by small variations in …


A Micromechanics-Based Multiscale Approach Toward Continental Deformation, With Application To Ductile High-Strain Zones And Quartz Flow Laws, Xi Lu Feb 2020

A Micromechanics-Based Multiscale Approach Toward Continental Deformation, With Application To Ductile High-Strain Zones And Quartz Flow Laws, Xi Lu

Electronic Thesis and Dissertation Repository

Earth’s lithosphere may be regarded as a composite material made of rheologically heterogeneous elements. The presence of these heterogeneous elements causes flow partitioning, making the deformation of Earth’s lithosphere heterogeneous on all observation scales. Understanding the multiscale heterogeneous deformation and the overall rheology of the lithosphere is very important in structural geology and tectonics. The overall rheology of Earth’s lithosphere on a given observation scale must be obtained from the properties of all constituents and may evolve during the deformation due to the fabric development. Both the problem of flow partitioning and characterization of the overall rheology are closely related …


Rare-Metal Alkaline Granite From The Arabian Shield, Saudi Arabia, Abdullah A. Aseri Feb 2020

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 …


Stratigraphic Studies Of Late Albian Strata, North-Eastern Alberta., Arwa Zourob Jan 2020

Stratigraphic Studies Of Late Albian Strata, North-Eastern Alberta., Arwa Zourob

Electronic Thesis and Dissertation Repository

Late Albian rocks of the Upper Viking, Westgate and lower Fish Scales alloformations were deposited about 101-100 Ma in the Western Canada Foreland Basin. Sediments in the study area span the forebulge, and are dominated by mudstone which forms 5-15 m thick, siltier-or sandier-upward sucessions bounded by marine flooding surfaces. Stratification is on a mm scale and represents storm deposits and fluid muds. Viking allomember VD and Westgate allomembers WA, WB and WC all thin towards the E and S and progressively onlap the forebulge. They record relative sea-level rise and gradual drowning and subsidence of the forebulge. In contrast, …


Quantification Of Surface Roughness Of Lava Flows On Mars, Carolina Rodriguez Sanchez-Vahamonde Dec 2019

Quantification Of Surface Roughness Of Lava Flows On Mars, Carolina Rodriguez Sanchez-Vahamonde

Electronic Thesis and Dissertation Repository

Volcanism has played a significant role throughout Mars’ geologic history. Extensive lava flows are widely spread across Mars’ equatorial region, shaping the surface in a very distinct way. In radar images (at the decimeter scale), these flows are bright, which is a typical characteristic of extremely rough, blocky lavas flows seen on Earth. Although the source of the extreme roughness of Martian lava flows is unknown, their surface roughness parameters can be constrained to 1) gain information about Mars’ interior processes, 2) find appropriate analogues on other planetary bodies, and 3) ideally infer the emplacement style of such lavas. Here, …


Numerical Simulations Of Complex Crater Formation In Layered And Mixed Targets, Ryan Hopkins Dec 2019

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 …


Shock Effects Recorded By The U-Pb Radiometric System In Zircons Of Apollo 17 Impact Breccias And By Raman Spectroscopy In Enstatite Meteorites, Bidong Zhang Sep 2019

Shock Effects Recorded By The U-Pb Radiometric System In Zircons Of Apollo 17 Impact Breccias And By Raman Spectroscopy In Enstatite Meteorites, Bidong Zhang

Electronic Thesis and Dissertation Repository

Impact cratering processes and formations are ubiquitous on the rocky planets within the Solar System. The Earth-Moon system was formed by a massive planetary impact, and numerous impacts afterwards significantly reshaped the topography and lithology of the Moon surface. This dissertation focuses on studying some specific geochemical, geochronological, and geophysical signatures of impact processes preserved in lunar rocks and asteroidal meteorites.

The zircon U-Pb radiometric system is one of the most reliable geochronometers in measuring geological time. Recently, unsupported radiogenic Pb enrichment has been reported to compromise the accuracy and precision of zircon U-Pb geochronometer in terrestrial rocks. In Chapter …


Ni And Fe Isotope Fractionation During Weathering And The Formation Of Ni Laterite Ore Deposits In The Philippines, Congxi Zhu Sep 2019

Ni And Fe Isotope Fractionation During Weathering And The Formation Of Ni Laterite Ore Deposits In The Philippines, Congxi Zhu

Electronic Thesis and Dissertation Repository

Weathering processes on Ni-rich ultramafic rocks in tropical areas produce laterites that become exploitable for Ni mining. To better understand these processes, samples were collected stratigraphically with water samples from several Ni mines in the Philippines and studied for Ni and Fe isotope compositions. This study found that Ni isotope fractionation takes place during the formation of Ni-enriched minerals (goethite), when light Ni isotopes are preferentially incorporated into new minerals formed, leaving heavy Ni isotopes in groundwater. The Δ60NiLimonite-Bedrock is up to -0.19 ± 0.32‰. Even though Fe is partitioned with redox state change during these reactions, …


Creating Calibration Curves Using In Situ X-Ray Diffraction To Determine The Shock Pressure Experienced By Clinopyroxene, Laura Jenkins Aug 2019

Creating Calibration Curves Using In Situ X-Ray Diffraction To Determine The Shock Pressure Experienced By Clinopyroxene, Laura Jenkins

Electronic Thesis and Dissertation Repository

This work extends on two quantitative methods for evaluating shock metamorphism to include clinopyroxene using X-ray diffraction (XRD). Clinopyroxene samples experimentally shocked to known shock pressures were studied with XRD. Lattice strain (ε) and strain-related mosaicity (SRM) were measured for each sample and plotted against their known shock pressures, creating a ε versus shock pressure calibration curve and an SRM versus shock pressure calibration curve. These calibration curves were applied to three meteorites: Nakhla, Zagami, and ALHA 77005. The SRM calibration curve gave peak shock pressures of 12±8 GPa for Nakhla, 44±8 GPa for Zagami, and 68±8 GPa for ALHA …


Calcium Isotopes In The Saint Agatha Kettle Lake Deposits Of Southern Ontario, Emma-Dawn Ferguson Jul 2019

Calcium Isotopes In The Saint Agatha Kettle Lake Deposits Of Southern Ontario, Emma-Dawn Ferguson

Electronic Thesis and Dissertation Repository

The St. Agatha kettle lake deposits, ON, Canada, contain a thick section of endogenic marl and coeval shelly fauna. Marl accumulation occurred from ~13,500 to ~8,200 cal yrs BP. This study examines controls on marl and shell δ44/42Ca, element ratios (Mg, Fe, and Ba), δ18O, δ13C, and 87Sr/86Sr ratios of marl calcite, shell aragonite, groundwater, and bedrock as proxies for paleolacustrine conditions. Results for Interval A (532.0 to 475.0cm) indicates a cooler, wetter climate, lower primary lake productivity and higher lake levels. Interval B (475.0 to 345.0cm) marks the onset of …


Detrital Zircon Geochronology Of Paleoproterozoic Sedimentary Rocks From The Upper Huronian Supergroup, Canada, Carolyn M. Hill, Don W. Davis, Patricia L. Corcoran Jun 2019

Detrital Zircon Geochronology Of Paleoproterozoic Sedimentary Rocks From The Upper Huronian Supergroup, Canada, Carolyn M. Hill, Don W. Davis, Patricia L. Corcoran

Western Research Forum

The Huronian Supergroup is a well-known succession of primarily sedimentary rocks exposed north of Lake Huron. Deposition of the succession is constrained between 2450 and 2220 Ma (million years), which corresponds with Earth’s rise of atmospheric oxygen, however the depositional timing of the uppermost formations cannot be refined further due to a lack of interbedded volcanic rocks. A geochronological study of detrital zircon grains from sandstone and claystone beds from the two youngest Huronian formations, the Gordon Lake and Bar River formations, was completed in order to confine the maximum age of deposition.

Zircon is a mineral that commonly forms …