Paramagnetic Defects in Detrital Quartz Along the Sandstone-Basement Unconformity of the Athabasca Basin: Evidence for Basin-Wide Uranium-Bearing Fluids A Thesis Submitted to the College of Graduate and Postdoctoral Studies In Partial Fulfillment of the Requirements For the Degree of Master of Science In the Department of Geological Sciences University of Saskatchewan Saskatoon By Eli Wiens © Copyright Eli Wiens, April 2022. All rights reserved. Unless otherwise noted, copyright of the material in this thesis belongs to the author i Permission to Use In presenting this thesis/dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis/dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis/dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis/dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis/dissertation. Disclaimer Requests for permission to copy or to make other uses of materials in this thesis/dissertation in whole or part should be addressed to: Head of the Department of Geological Sciences 114 Science Place University of Saskatchewan Saskatoon, Saskatchewan S7N 5E2 Canada OR Dean College of Graduate and Postdoctoral Studies University of Saskatchewan 116 Thorvaldson Building, 110 Science Place Saskatoon, Saskatchewan S7N 5C9 Canadaii Abstract Radiation-induced defects in quartz have been studied at select localities throughout the Athabasca Basin, which hosts world-class unconformity-associated uranium deposits, and revealed various silicon-vacancy defects associated with cathodoluminescent rims formed by α-radiation. In this thesis, paramagnetic defects in detrital quartz were quantified using electron paramagnetic resonance (EPR) spectroscopy, with samples taken near the sandstone-basement unconformity from 48 diamond drill holes spread throughout the Athabasca Basin. Radiation-induced defects were observed in all samples in concentrations similar to those previously measured in the Athabasca Basin, including detrital quartz near the Arrow and McArthur River deposits. Partial dissolution experiments indicate that the core of detrital quartz grains contain minimal paramagnetic defect concentrations, with high concentrations of silicon-vacancy defects limited to the exterior of the detrital grains. This is consistent with α-particle irradiation, which has limited penetration in quartz, originating from a source external to the grains. As the paramagnetic defects are concentrated in the exterior of the quartz grains, they are expected to be contained within secondary overgrowths and therefore less affected by differences in the underlying detrital quartz. Modelled dose rates calculated from sample U and Th concentrations are not well correlated with the concentration of paramagnetic defects, suggesting that the defects are not formed primarily due to radionuclides present in the sample. These features support a temporary source of radiation as partially responsible for forming these defects, such as a uranium-bearing fluid, that was present throughout the basin at the sandstone-basement unconformity. Detrital quartz samples from the Athabasca Basin generally feature H′3, peaks at g = 2.035 and g = 2.017, #3 and E′1 along with lesser amounts of other hole centers including H′1, H′2 and H′7(III). Powder EPR simulations were unable to fit the g = 2.035 and g = 2.017 signals, which are not observed in previously published drusy quartz powder EPR spectra. Attempts to differentiate the signals at g = 2.035 and g = 2.017 as individual defects were inconclusive. Further single-crystal EPR studies of detrital quartz from the Athabasca Basin to characterize these unknown signals at g = 2.035 and g = 2.017 are warranted. iii Acknowledgements Many thanks for the continued patience and support of my supervisor, Dr. Pan, and for the opportunity of learning and applying spectroscopy in general. The staff of the Saskatchewan Structural Sciences Center, in particular Dr. Sammynaiken, are thanked for their assistance with EPR. Thank you to Sean Bosman and the staff at the Subsurface Geological Laboratory for access and assistance with sampling at the Saskatchewan Geological Survey core collection, to Blaine Novakovski for thin section preparation, and Nasreen Mosa at the Saskatchewan Isotope Laboratory for assistance with HF related lab work. I would also like to acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) for funding provided through a Canada Graduate Scholarship – Master’s (CGS M), and a Discovery Grant to Dr. Pan which covered all analytical and other costs.iv Table of Contents Permission to Use ........................................................................................................................... i Abstract .......................................................................................................................................... ii Acknowledgements ...................................................................................................................... iii Chapter 1: Introduction and Objectives ..................................................................................... 1 1.1. Research Objectives ............................................................................................................. 2 1.2. Chapter Description.............................................................................................................. 2 Chapter 2: Geological Background ............................................................................................. 3 2.1. Basal Stratigraphy ................................................................................................................ 5 2.2. Unconformity ....................................................................................................................... 6 2.3. Overgrowths of quartz .......................................................................................................... 8 2.4. Uranium Mineralization and Fluids ..................................................................................... 8 Chapter 3: Electron Paramagnetic Resonance and Radiation Induced Defects in Quartz . 10 3.1. Background ........................................................................................................................ 10 3.1.1. Zeeman Splitting.......................................................................................................... 10 3.1.2. Nuclear Hyperfine Splitting......................................................................................... 11 3.1.3. Power Response ........................................................................................................... 11 3.1.4. EPR Spectra ................................................................................................................. 12 3.2. Radiation-induced Defects in Quartz ................................................................................. 13 3.2.1. Silicon-Vacancy Defects ............................................................................................. 16 3.2.2. Oxygen-Vacancy Defects ............................................................................................ 17 3.2.3. Aluminum-related Defects .......................................................................................... 18 3.3. Distribution of Paramagnetic Defects in Quartz from the Athabasca Basin ...................... 18 Chapter 4: Sampling, Analytical Methods and Petrography ................................................. 21 v 4.1. Sample Selection ................................................................................................................ 21 4.1.1. Single Crystal Selection............................................................................................... 24 4.1.2. Reference Samples ...................................................................................................... 24 4.2. Procedure ............................................................................................................................ 25 4.2.1. Sample Preparation and EPR Analysis ........................................................................ 25 4.2.2. Powder EPR Data Processing ...................................................................................... 26 4.2.3. Single Crystal EPR Data Processing ........................................................................... 27 4.2.4. Powder EPR Simulations............................................................................................. 28 4.2.5. Isochronal Annealing ................................................................................................... 28 4.2.6. Microwave Power Response ....................................................................................... 28 4.2.7. Low Temperature ........................................................................................................ 29 4.2.8. Geochemistry ............................................................................................................... 29 4.2.9. Partial Dissolution ....................................................................................................... 29 4.3. Core Description and Petrography ..................................................................................... 30 Chapter 5: Powder EPR Spectra ............................................................................................... 34 5.1. Introduction ........................................................................................................................ 34 5.2. Powder EPR Simulations ................................................................................................... 34 5.3. Defect Properties and Associations .................................................................................... 36 5.3.1. Power Saturation and Low Temperature Analyses ..................................................... 36 5.3.2. Thermal Annealing ...................................................................................................... 40 5.3.3. Single Crystal Analyses ............................................................................................... 42 5.3.4. Defect Associations ..................................................................................................... 45 5.3.5. Summary ...................................................................................................................... 49 Chapter 6: Distribution of RID and Evidence for Basin-Wide Uranium-Bearing Fluids ... 50 6.1. Overview ............................................................................................................................ 50 vi 6.2. Geochemistry ..................................................................................................................... 54 6.3. Partial Dissolution .............................................................................................................. 56 6.3.1. Overgrowths ................................................................................................................ 58 6.4. Evidence for basin-wide uranium-bearing fluids ............................................................... 62 Chapter 7: Summary and Future Outlook ............................................................................... 63 References .................................................................................................................................... 65 Appendices ................................................................................................................................... 73 Appendix A. Comparison of Quartz and Clay EPR Signal Intensity.................................... 73 Appendix B. Geochemistry Data .......................................................................................... 74 Appendix C. EPR Data ......................................................................................................... 77 Appendix D. Sampling Data ................................................................................................. 80 List of Figures Figure 2.1 – Location map of the Athabasca Basin. ...................................................................... 4 Figure 2.2 – Athabasca supergroup stratigraphy ........................................................................... 6 Figure 3.1 – Simulation of H′1 powder EPR spectrum. ............................................................... 13 Figure 3.2 – Schematic structure of defects in quartz. ................................................................. 14 Figure 4.1 – Sampling flow chart................................................................................................. 22 Figure 4.2 – Drillhole location map ............................................................................................. 23 Figure 4.3 – Line Position Roadmap ........................................................................................... 28 Figure 4.4 – Core photographs ..................................................................................................... 31 Figure 4.5 – Thin section photomicrographs and core photograph. ............................................ 33 Figure 5.1 – Experimental and simulated powder EPR spectrum of sample DV10-001 (I)........ 35 Figure 5.2 –Experimental and simulated powder EPR spectrum of sample CLC13-066 (II). .... 36 Figure 5.3 – Power response of 003 (I). ....................................................................................... 37 Figure 5.4 – Low temperature powder EPR spectra of sample HAR-05 (I) ................................ 38 Figure 5.5 – Expansion of low temperature powder EPR spectra of sample HAR-05 (I) ........... 39 Figure 5.6 – Power response of LA0-5 (I). .................................................................................. 40 vii Figure 5.7 – Summary of HAR-05 (I) isochronal annealing ....................................................... 41 Figure 5.8 – Isochronal annealing of sample HAR-05 (I). .......................................................... 42 Figure 5.9 – Experimental and simulated single crystal spectrum from sample 003 (I) ............. 43 Figure 5.10 - Simulated roadmap of H′3 (II) overlain on the single crystal spectra. ................... 44 Figure 5.11 - Simulated roadmap of H′1 overlain upon the experimental single crystal spectra . 44 Figure 5.12 – Powder spectra from sample 003 and single crystal .............................................. 45 Figure 5.13 – Height of g = 2.049 peak vs. the peak to peak amplitude of the gint .................... 46 Figure 5.14 - Peak to peak amplitude of the signal at g = 2.017 vs. the peak height at 2.035 ..... 47 Figure 5.15 - The height of the peak at g = 2.035 vs. the peak to peak amplitude of the gint ..... 47 Figure 5.16 - Height of g = 2.049 peak attributable vs. the height of the peak at 2.035.............. 48 Figure 5.17 - The peak to peak amplitude of the gint vs. the peak height at 2.035....................... 48 Figure 6.1 – Comparison of the gint amplitude ............................................................................. 51 Figure 6.2 - Height of g = 2.049 peak attributable to H′3 ............................................................ 52 Figure 6.3 - Unconformity depth vs. gint amplitude. .................................................................... 53 Figure 6.4 – Unconformity depth vs. the ratio of the peak heights at g = 2.035 and 2.049 ......... 53 Figure 6.5 – Amplitude of the signal at g = 2.007 vs. the uranium concentration. ...................... 54 Figure 6.6 – Amplitude of the signal at g = 2.007 vs. the thorium concentration. ...................... 55 Figure 6.7 – Amplitude of the signal at g = 2.007 vs. the modelled dose rate............................. 55 Figure 6.8 – Partial dissolution of P9-81-02 (II). ......................................................................... 57 Figure 6.9 - Partial dissolution of HAR-05. ................................................................................. 58 Figure 6.10 – Powder EPR spectra of low concentration dissolved samples. ............................. 60 Figure 6.11 – Overgrowth photographs ....................................................................................... 61 Figure 6.12 – EPR spectra of LA0-5 (I) before and after partial dissolution .............................. 61 List of Tables Table 3.1 – Defects in α-quartz .................................................................................................... 15 Table 3.2 – Activation energy of select silicon-vacancy defects. ................................................ 17 Table 6.1 - Change in gint intensity with partial dissolution. ........................................................ 56 List of Equations viii Equation 3.1 – Zeeman splitting. ................................................................................................. 10 Equation 3.2 – Boltzmann distribution. ....................................................................................... 11 Equation 3.3 – Second order decay ............................................................................................. 17 Equation 3.4 – Decay constant. ................................................................................................... 17 Equation 4.1 – Modelled radius change of sphere as a function of mass .................................... 30 Equation 4.2 – Relative defect concentration in dissolved material............................................ 30 1 Chapter 1: Introduction and Objectives The Paleoproterozoic Athabasca Basin in northern Saskatchewan hosts world-class unconformity-associated uranium deposits, formed in part by extensive fluid flow throughout the basin. The contrast in permeability between the relatively permeable Athabasca Supergroup sandstones and the underlying crystalline basement forms a regional boundary for fluid circulation in the basin along the unconformity (Hoeve and Quirt 1984, Jefferson et al. 2007; Wang et al. 2021), and radiogenic lead isotope ratios indicate preferential fluid flow along the unconformity (Holk et al. 2003). The unconformity also separates the saline, oxidizing basinal brines from the relatively reduced fluid present in the basement, making the unconformity a potential location of fluid mixing and reduction of soluble U6+ complexes to precipitated U4+. However, this is dependant upon the presence of uranium in the fluids. Uranium-rich fluid inclusions in minerals such as quartz are present throughout the basin, ranging from up to 600 ppm near mineralization (Richard et al. 2010, 2012) to an average of 7 ppm in areas away from known mineralization (Chi et al. 2019). Inclusions at the boundary between detrital quartz and overgrowths also indicate the diagenetic fluids contain elevated uranium concentrations (e.g. compared to typical compositions of formation waters or sea water), however these detailed measurements are limited to 4 drill holes spread throughout the basin (Chi et al. 2019). Electron paramagnetic resonance (EPR) and cathodoluminescence (CL) measurements of radiation-induced defects (RID) in quartz from the Athabasca Basin have identified defects formed by α-particle irradiation, providing direct evidence of exposure to radiation emitted by the decay of uranium, thorium and their radioactive daughter isotopes (Botis et al. 2005, Hu et al. 2008). High concentrations of RID are also observed in various clay minerals from the Athabasca Basin using EPR (Morichon et al. 2010, Allard et al. 2018). The occurrence of elevated α-particle-induced defects where U and Th are not present likely records exposure to uranium-bearing fluids or temporary mineralization (Pan et al. 2010). Conversely, relatively low concentrations of RID in locations with extensive hydrothermal alteration, as observed in the 2 Maw Zone (Pan et al. 2013), may indicate an absence of uranium in the fluid. 1.1. Research Objectives This thesis is a basin wide study of radiation-induced defects in quartz from sandstone samples directly overlying the unconformity using EPR. The main purpose is to quantify radiation-induced defects across the basin and compare with radionuclide contents of the samples. The defect concentrations of select samples are also measured after partial dissolution, which is expected to preferentially remove α-radiation-induced defects due to their limited penetration in solids, and remove overgrowth material from the core of the detrital quartz grains. Defect concentrations are also compared to previous EPR studies of samples from mineralized areas. Finally, the types of defects are discussed and trends relating to sample location are considered. 1.2. Chapter Description Chapters 2 and 3 review and discuss the background geology, EPR methodology and details of relevant radiation-induced defects in quartz. Details of the sampling method, preparation procedure and EPR analyses are presented in Chapter 4. In Chapter 5 the powder EPR measurements and simulations are discussed, as well as experiments intended to identify the individual defects present. Chapter 6 discusses and compares the defect concentrations as well as their relationship to radionuclide concentrations and sample location. Finally, Chapter 7 provides a summary and potential implications of the results. 3 Chapter 2: Geological Background The Athabasca Basin of northern Saskatchewan and Alberta (figure 2.1) is a Paleoproterozoic intracratonic sedimentary basin located above the boundary of the Rae and Hearne provinces, and is composed of three stacked sub-basins with depositional ages from an estimated ca. 1.76 Ga to 1.5 Ga (Ramaekers et al. 2007, Bosman and Ramaekers 2015). These three sub-basins separate three of the four primary depositional sequences bounded by unconformities. Sediments are sourced from a variety of directions, and the range of proximal sediments, such as was mainly deposited in the first two sequences, is estimated to be less than 150 km (Ramaekers et al. 2007). The total stratotype thickness is 3.8 km, in contrast to the maximum vertical thickness preserved around 1.5 km, indicating extensive reworking and erosion (Ramaekers et al. 2007). Most of the preserved basin is composed of unmetamorphosed quartzose, fluvial sandstone overlying Archean to Paleoproterozoic igneous and metamorphic basement rocks. The Athabasca Basin is host to high grade unconformity related uranium deposits, which occur throughout the basin. Dating of uraninite and associated alteration minerals indicates a primary mineralization age of ~1.59 Ga, with a protracted history of uranium remobilization and deposition due to fluid circulation induced by far-field orogenic and tectonic events (e.g. Alexandre et al. 2007). 4 Figure 2.1 – Location map of Athabasca Basin in Canada (Statistics Canada 2016) with Precambrian domains labelled in expansion (Alberta Energy Regulator 2021, Saskatchewan Ministry of Energy and Resources 2022). Uranium mines are labelled, with triangles indicating deposits (i.e. developed prospects). 5 2.1. Basal Stratigraphy The Fair Point Group defines the northeast-trending trough of the Jackfish Subbasin on the western side of the current basin, and is the only unit in the first depositional sequence (Fig. 2.2). The Fair Point Group has a maximum thickness of about 380m with fining upwards trend in general, and had an arkosic composition before diagenesis, which transformed the feldspars into clay mineral pseudomorphs (Ramaekers 1981, Ramaekers et al. 2007). Paleocurrent directions and sedimentology indicate transportation mostly in hyper-concentrated, sheet and debris flows as well as minor braided streams from a nearby sources ranging from the north to southeast, categorized as the Fiddler deposystem (Ramaekers et al. 2007, Bosman 2014). A bimodal zircon age distribution of 2.61- 2.52 Ga and ca. 1.9 Ga suggests possible source terrains such as the western Rae Province (e.g. the Taltson-Thelon magmatic zone and Snowbird Tectonic Zone), Sask Craton, and Trans Hudson Orogen (Rainbird et al. 2007). The second sequence was deposited in the extensive Cree Subbasin and forms the sandstone-basement unconformity in most of the Athabasca Basin. The earliest unit, the Smart Formation, is composed of interbedded eolian and fluvial sediments with a maximum thickness of 120 m (figure 2.2). The Smart Formation is mostly restricted to the western side of the basin, and may be partially composed of reworked sediment from the Fair Point Group (Ramaekers et al. 2007). The Read Formation overlies the Smart, but is interpreted as its eastern lateral equivalent separated by the Clearwater Domain, and also deposited in arid conditions (Bosman et al. 2013). The Read Formation is dominated by sheet-flood and braided fluvial deposits derived from a proximal source from the southeast, with a maximum observed thickness of 170 m (Ramaekers et al. 2007). The relatively small amount of thorium in the Read Formation is attributed to intense weathering of heavy minerals and further alteration during early diagenesis (Ramaekers et al. 2007). The Bird Formation is characterized by thin quartz pebble conglomerate beds with anomalously high gamma emission due to thorium, which occurs in crandallite-group minerals on the eastern side of the basin. The crandallite-group minerals are coeval with quartz cementation and interpreted to be hydrothermal in origin, and are concentrated in conglomeratic layers due to presence of precursor minerals such as monazite (Mwenifumbo and Bernius 2007). The Bird Formation is dominated by proximal braided stream and sheetflow deposits, and was deposited in a number of interfingering deposystems along with the younger units of the Manitou 6 Falls Formation (Ramaekers et al. 2007). This stratigraphy, including the Bird, Collins, Warnes, Hodge and Clampitt-Dunlop formations, is interpreted as a megafan complex migrating towards the Snowbird Tectonic Zone in a more humid climate, with a variable thickness to a maximum of more than 1 km. Detrital zircon ages from the Bird and Dunlop Formations are varied but are dominantly around ca. 2.58 Ga and ca. 1.85 – 1.83 Ga, consistent with influx from the Hearne province and Trans-Hudson Orogen respectively (Rainbird et al. 2007). Figure 2.2 – Athabasca supergroup stratigraphy, including sections from two drillholes. The Collins formation grades into the overlying Warnes formation and is undifferentiated and labelled as Warnes in this figure. The Beartooth (FPb) and Lobstick Island (FPI) formations of the Fair Point group and the Brule (Wb) and Claussen (Wc) formations of the Wolverine Point group are also undifferentiated. Data published in DF39 by Bosman and Ramaekers (2015) 2.2. Unconformity 7 The unconformity between the generally permeable, oxidized Athabasca Supergroup sandstones with the relatively impermeable reduced basement underlying (figure 2.2) is an important hydraulic barrier. The influence of the unconformity on fluid flow has been demonstrated in fluid modelling (e.g. Chi et al. 2013, Li 2016; Wang et al. 2021), and has been suggested to serve as a pathway for uranium-bearing fluids (Holk et al. 2003, Botis et al. 2006). The topography and slope of the unconformity surface are primarily controlled by paleotopography and syn- to post-depositional faulting, which can both be related to earlier deformational events such as reactivated faults (Ramaekers et al. 2007, Li et al. 2015). Resistive quartzite units form paleotopographic ridges, in contrast to pelitic units which tend to develop deep weathering profiles (Macdonald 1980). These quartzite ridges may be fault bounded compressional pop-up structures (Jefferson et al. 2007) or alternatively, hydrothermal in origin, and form in zones of higher permeability enhanced by nearby faulting (Card 2012, 2013). Quartzite units are spatially associated with some large deposits such as McArthur River and Phoenix, and have also been proposed as a possible barrier to uranium-bearing fluids in the Maw Zone (Hu et al. 2008). Paleotopography was sufficiently varied to commonly produce significant variability in paleocurrent directions in the basal sandstone units, such as the Bird Formation (Ramaekers et al. 2007). Paleovalleys channelized sediments, produced onlapping relationships between basal Athabasca stratigraphy and basement e.g. Deilmann pit of the Key Lake deposit and the Sue C pit at McClean Lake (Harvey 1999, Long 2007). If a permeability contrast is present, such as mudstone layers inhibiting upward flow, these structures could channelize fluid flow along the unconformity (Harvey and Bethune 2007). Conglomeratic basal lag is commonly situated directly above the unconformity, and is composed of reworked paleosol and coarse material that has remained in situ (Ramaekers et al. 2007). These basal lag deposits are inconsistent in thickness and are intercalated with overlying units in some locations (Ramaekers et al. 2007). Beneath the unconformity, the basement has characteristic hematite and chlorite alteration, commonly referred to as the red and green zones respectively, or a mixture of both in the transitional red-green zone. The transition from hematitic to chloritic alteration reflects the transition of the dominant oxidation state of iron from oxidized near the unconformity to reduced in the basement (Hoeve and Quirt 1984). The dominant alteration process has been interpreted as either paleoweathering or diagenetic 8 alteration. The deep, oxidized weathering profile developed is consistent with lateritic weathering, which is typically formed in humid climates but can also be found in arid and temperate climates (Macdonald 1980, Yeo et al. 2001). However, paleosol related textures are very rarely observed (Jefferson et al. 2007). The red and green zones are overprinted in some locations by clay alteration in the bleached zone, formed due to hydrothermal alteration (MacDonald, 1985). 2.3. Overgrowths of quartz The earliest overgrowth generation, Qa, has been identified on the eastern side of the Athabasca Basin, and formed at shallow depths before compaction (Hiatt et al. 2007) and temperatures < 70°C (Hiatt and Kyser 2007). Qa commonly forms a meniscal bridge between grains, is syntaxial, and contains hematite inclusions. Early quartz cement is typically located below paleoweathering surfaces, which are accompanied by intense hematization, vugs, and infiltrated clays (Hiatt et al. 2007). Q1 has pressure solution textures such as convex-concave contacts (Hiatt et al. 2007), is clear, euhedral and contains fluid inclusions with salinities of 10 – 25% and homogenization temperatures of 150 – 170°C (Kotzer and Kyser 1995). Hematite coatings are also commonly present on the surfaces of detrital quartz grains that are later overgrown by Q1 (Jefferson et al. 2007). Early overgrowths (Qa + Q1) are thick, up to 250μm (Hiatt et al. 2007), making them generally thicker than the penetration distance of α-radiation. Quartz dissolution can occur in sandstones due to reaction with silica-undersaturated fluid. Silica-undersaturated fluids in the Athabasca Basin are likely derived from the basement, and extensive quartz dissolution is expected to be localized to areas of basement fluid egress such as faults (Jefferson et al. 2007). Dissolution may also create voids for the growth of subsequent quartz generations (Q2 & Q3), which tend to form as druses in fractures and vugs. Quartz dissolution can also occur in minor amounts due to replacement by dickite (Hiatt and Kyser 2007). 2.4. Uranium Mineralization and Fluids 9 The Athabasca Basin has a protracted and complex fluid history, with primary uranium mineralization at ca. 1.59 Ga, and several remobilization events associated with fluid circulation potentially restarting during far field tectonic events (Alexandre et al. 2007). Brines with very high concentrations of uranium (up to 600 ppm) are found near uranium mineralization (Richard et al. 2010), and the uranium concentrations in diagenetic fluids at locations far from known mineralization are high relative to typical basinal fluids, suggesting uranium-rich fluids circulated extensively in the basin (Chi et al. 2019). The high permeability of the unmetamorphosed clastic basin fill relative to the basement, combined with the oxidized conditions present in the basin, provide conditions suitable for the widespread circulation of U6+ in solution in the form of the uranyl ion UO22+ (Cuney 2010) or uranyl chloride complexes. NaCl and CaCl2-rich brines have been identified at major deposits as well as in regional drill cores, and are consistent with seawater derived brines from a single parent and differentiated along distinct flow path through fluid-rock interaction and mixing (Richard et al. 2011, 2015). The NaCl-rich and CaCl2-rich brines have temperatures of around 180°C and 120°C respectively (Richard et al. 2015), and the high concentrations of uranium in solution suggest an acidic pH between 2.5 – 4.5 (Richard et al. 2012), likely controlled by the kaolinite-illite buffer (Cuney et al. 2003). Uraninite UO2 can be precipitated by reduction to the U4+ oxidation state, possibly by interaction with reducing basement fluids (e.g. Hoeve and Quirt 1987, Fayek and Kyser 1997). 10 Chapter 3: Electron Paramagnetic Resonance and Radiation Induced Defects in Quartz 3.1. Background Electron paramagnetic resonance (EPR) spectroscopy, also known as electron spin resonance (ESR), is a technique used to study materials containing unpaired electrons such as radicals and transition elements. Irradiation can be used to produce paramagnetic point defects in many diamagnetic materials, making them EPR-active. Continuous-wave (CW) EPR can be used to rapidly identify and quantify paramagnetic defects using a powder, or characterize the local structural environment in greater detail using a single crystal. The high sensitivity of EPR spectrometers allows the measurement of low concentrations of paramagnetic radiation-induced defects relative to alternative techniques such as cathodoluminescence (CL) imaging and Raman spectroscopy, although the results are not necessarily directly comparable. 3.1.1. Zeeman Splitting EPR spectroscopy is dependant upon the Zeeman effect, which describes the splitting of degenerate electron spin states in the presence of a magnetic field. This splitting is due to the magnetic dipole moment of the unpaired electron interacting with the magnetic field for both possible values of the magnetic spin quantum number (𝑀𝑠 = ±1/2), which aligns parallel or anti-parallel to the field. When the energy difference between the spin states is matched by the photon energy (at microwave frequencies), absorption occurs. For the free electron, the resonance condition is described by the following equation: ℎ𝜈 = 𝑔𝑒𝛽𝑒𝐵 (3.1) Equation 3.1 – Where ℎ is Planck’s constant, 𝜈 is frequency, 𝑔𝑒 = 2.00232 is the g-factor of the free electron, 𝛽𝑒 is the Bohr magneton and 𝐵 is the magnetic field. The local magnetic field at the unpaired electron must also be considered in addition to the external field to describe the effective magnetic field, but in practice B is taken as the applied external field, and g is used to describe the deviation from ge due to spin-orbit coupling. The g-11 value, which is dimensionless, can therefore be used to refer to transitions rather than stating both field and frequency values (for systems dominated by Zeeman splitting). Some paramagnetic centers do not require orientation information relative to the magnetic field direction. These systems are characterized by isotropic g-matrices, whereas anisotropic g-matrices describe systems with axial or rhombic symmetry. Anisotropic g-matrices can be diagonalized and expressed in terms of principal values (eigenvalues) and directions (often in spherical coordinates relative to the crystal symmetry) of the defect center. 3.1.2. Nuclear Hyperfine Splitting The interaction between unpaired electrons and nuclei with non-zero nuclear spin (I≠0) gives rise to hyperfine splitting. Hyperfine splitting may be isotropic due to Fermi contact interaction, where the magnitude is related to the electron-spin density at the nuclei, and anisotropic due to dipolar interaction, which is dependant upon the distance of the nucleus relative to the unpaired electron. This leads to a splitting of the EPR signals into 2I + 1 hyperfine lines, where I is again the nuclear spin quantum number. In general, nuclei with even numbers of protons and neutrons will have no nuclear spin, the remaining nuclei with even mass numbers will have integer spin, and conversely odd mass number nuclei will have half integer spin. The prevalence of the hyperfine peaks correlates with the natural abundance of the isotope and the number of nuclei, and the presence of multiple isotopes may lead to multiple sets of hyperfine lines, for example 29Si (I = ½ and 4.7%) weak satellite lines around a strong central transition not split by 28Si and 30Si (92.2% and 3.1%, respectively, and I = 0). 3.1.3. Power Response In absence of saturation, the signal strength of EPR resonance is directly proportionally to number of paramagnetic centers present. The ratio of the two spin states is described by the Boltzmann distribution: 𝑁𝑢𝑁𝑙= 𝑒𝑥𝑝 (−∆𝑈𝑘𝑏𝑇𝑠) (3.2) Equation 3.2 – Boltzmann distribution: where 𝑢 and 𝑙 are the upper and lower energy level spin states, respectively. ∆𝑈 is the energy difference between spin states, 𝑘𝑏 is the Boltzmann constant and 𝑇𝑠 is the spin temperature. 12 The spin temperature describes the energy of the system, which reaches a steady-state with the microwave power via loss of energy through relaxation processes. The spin-system may dissipate energy through spin-lattice relaxation, which is temperature dependant, and spin-spin relaxation, which is concentration dependant, as well as many other potential relaxation processes. At high spin temperatures, there may not be a large enough population in the lower spin state to absorb microwave radiation, resulting in power saturation. In absence of saturation, the signal amplitude is proportional to the square root of power, however with increasing saturation there is a diminished response to power and peak broadening. The signal may become undetectable when exposed to higher microwave powers (e.g. E′1 is not observed at 63 mW in the spectrometer configuration used in this thesis). 3.1.4. EPR Spectra In single crystals, a paramagnetic center is in a number of sites with different orientations, rotated relative to one another according to the symmetry of the Laue class of the host crystal. Line position ‘roadmaps’ can be produced by measuring the line position of the sites throughout rotation of the crystal, which can be used to determine the g matrix of the paramagnetic center if the crystal orientation is known, or determine the crystal orientation by fitting to the g matrix of an already known center. In contrast, powder analyses are orientation independent, as infinite numbers of crystal orientations are measured simultaneously. EPR spectrometers measure the first derivative of absorption due to the use of field modulation, and therefore the powder spectra contain signals at the principal g-values (figure 3.1), corresponding to changes in the slope of the powder absorption curve. 13 Figure 3.1 – Simulation of H′1 powder EPR spectrum (left panel) and its first integral (right panel), which is an absorption curve (X-band frequencies, 1 G line width). 3.2. Radiation-induced Defects in Quartz A variety of paramagnetic defects have been reported in both detrital and drusy quartz from the Athabasca Basin, and those detectable at room temperature are listed in table 3.1. Oxygen and silicon vacancy defects (e.g. figure 3.2) are called E (electron-like) and H (hole-like) defects respectively, grouped with numbers according to their structure, and primes indicate the number of unpaired electrons. Although Si and O vacancies are intrinsic defects, many of these defects are also accompanied by the presence of extrinsic impurities such as the substitution of Al3+ for Si4+ with additional charge balancing cations, which can result in superhyperfine splitting (Götze et al. 2021). Aluminum occurs naturally as the 27Al isotope, which has a nuclear spin of I = 5/2 that forms a six peak multiplet or sextet. The gmax and magnitude of 27Al hyperfine splitting are the primary distinguishing characteristics of silicon vacancy defects in X-band powder EPR spectra. The common electron-like center, E′1, has relatively little Zeeman splitting with g factors close to the free electron value (Mashkovtsev et al. 2013), a narrow linewidth and is in passage at low microwave power relative to silicon vacancy defects. 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valuegmaxgmingint1.992.002.012.022.032.042.052.06Absorbance (a.u.)g-valuegmaxgmingint14 Figure 3.2 – Schematic structure of quartz illustrating common types of defects. Modified from Götze (2012). 15 Table 3.1 – Select paramagnetic defects in α-quartz. References: 1 Weeks and Nelson (1960), 2 Mashkovtsev et al. (1978), 3 Maschmeyer et al. (1980), 4 Maschmeyer and Lehmann (1983), 5 Botis et al. (2008), 6 Nilges et al. (2008), 7 Pan et al. (2008), 8 Nilges et al. (2009), 9 Pan et al. (2009), 10 Mashkovtsev and Pan (2013) Center (Label) Electron Zeeman Splitting Hyperfine Coupling Reference Current Original gk θ (°) ϕ (°) Nucleus Ak (mT) θ (°) ϕ (°) H′1 #1 2.02945 26 266.2 Al27 0.024 79 352 2, 8 2.00765 64 91.2 -0.025 63 87 2.0021 88.1 0.2 -0.027 29 242 H′2(I) B 2.03505 22.1 172.6 Al27 -0.222 65 156 3, 7 2.00773 71.1 319.3 -0.292 42 36 2.00234 78.6 53.2 -0.3 58 263 H′2(II) B′ 2.03555 22.5 165.5 Al27 -0.27 62 156 3, 7 2.00771 69.5 319.5 -0.35 107 237 2.00231 80.9 52.9 -0.36 33 300 H′3(I) #4, D 2.04953 73.6 248.9 Al27 -0.038 73 28 2, 4, 9 2.00701 50.1 353 -0.14 77 122 2.00206 44.4 141.5 -0.146 20 248 H′3(II) #4, E 2.05175 76.4 244.1 Al27 0.02 51 302 2, 4, 9 2.00682 51.7 345.1 -0.092 38 128 2.00213 41.5 138.2 -0.101 92 214 H′4(I) G 2.031028 46.6 1 Al27 -0.305 120 121 4, 6 2.008095 84.1 265.4 -0.399 43 173 2.002355 43.9 169.3 -0.431 61 49 H′4(II) G′ 2.02925 46.8 0.7 Al27 -0.41 52 307 4, 7 2.00809 84.2 265.2 -0.51 39 146 2.00238 43.7 169.2 -0.54 80 44 H′7(I) C 2.0183 26.7 270 Al27 0.15 33 90 4 2.009 90 0 0.12 Axial 2.0033 63.3 90 0.12 H′7(II) C′ 2.01698 30.7 274.9 Al27 -0.1 53 309 7 2.00823 75.2 158.6 -0.21 57 191 2.00248 63.7 61.1 -0.22 52 72 H′7(III) X 2.0177 39.6 269.8 5 2.0076 89.5 0.4 2.0029 50.3 90.8 E′1 2.0017 65.8 47.6 Si29 45.277 65.96 49.76 1, 10 2.00044 47 162 39.068 58 156 2.00021 52 297 39.044 42 290 #3 2.0044 54 90 2 2.0008 36 270 2.0056 90 0 16 3.2.1. Silicon-Vacancy Defects Silicon vacancy in quartz leads to deficiency in positive charges and can result in hole trapping by the neighboring oxygen atoms in the form of O2- (superoxide), O22- (peroxide), O23-, and O3- (ozonide) radicals (Alessi et al. 2014). The O2- centers include H′1, H′2(I), H′2(II), H′3(I) (tentative), H′3(II), H′4(I) and H′4(II), formerly known as #1, B, B′, D, E, G and G′ respectively (Pan et al. 2008; Pan et al. 2009; Nilges et al. 2009). Centers commonly referred to as peroxy radicals include O2- centers formed from precursor peroxy linkages, which likely includes H′1, H′2(I), H′2(II) H′4(I) and H′4(II) (Nilges et al. 2009). The gmax of O2- centers is predicted to be along to the O-O pπ functionals and inversely proportional to the crystal field splitting of pπg* antibonding orbitals (Känzig and Cohen 1959). Experimental gmax values of H′1-4 are consistent with O2- bound to trivalent and tetravalent cations (Lunsford 1974, Alessi et al. 2014), and there is 27Al superhyperfine splitting present for all these superoxide defects, although not well resolved for H′1 at X-band frequencies. The diversity of peroxy radicals is likely due to the variation in the symmetry of the O-O pairs and the linkage to compensating Al3+ substitution at different sites (Pan et al. 2009). All of these superoxide/peroxy radicals are detectable at room temperature, increase in intensity up to 280°C and decay with second order kinetics before annealing at various temperatures. Superoxide radicals have also been shown to regenerate with gamma irradiation after annealing up to 800°C, indicating stability of their diamagnetic precursors (Pan and Hu 2009). Similar to E′1, the increase in intensity with heating is thought to be due to transfer from other less stable traps, rather than formation of new defects (Pan et al. 2009). The ozonide O3- radicals include H′7(I), H′7(II) and H′7(III), formerly known as C, C′ and X respectively. The ozonide radical is expected to have its gmax along an O-O direction with gmin≈ge perpendicular to the plane of the oxygen atoms (Schlick 1972). H′7(I) and H′7(II) centers have significant 27Al superhyperfine splitting, whereas H′7(III) has relatively small 27Al superhyperfine splitting that is not well resolved at X-band frequencies (Botis et al. 2008). The ozonide defects are observable at room temperature, and H′7(II) has been shown to regenerate with gamma irradiation after annealing to 800°. Additionally centers are notably absent from the former labelling schemes, such as those reported by Mashkovtsev et al. (1978), Maschmeyer et al. (1980) and Maschmeyer and Lehmann (1983), and have not been recognized in quartz from the Athabasca Basin (with the exception of 17 #3 in Pan and Hu, 2009), while others have been determined as misinterpretations in follow-up studies, e.g. #4 as a combination of H′3 (I) and H′3 (II) (Pan et al. 2009). H′5 and H′6 (formerly #6 and #7 respectively) are thought to be the O23- type centers and are only detectable at low temperatures (Pan et al. 2008). Silicon vacancy defects in quartz decay with second order kinetics (Pan et al. 2009, Pan and Hu 2009), which is concentration dependant and consistent with a paramagnetic defect combining with another approximately equally numerous defect (Toyoda and Ikeya 1991). Second order decay follows equation 3.3 and equation 3.4. 1𝑁= 𝜆𝑡 +1𝑁0(3.3) Equation 3.3 – Second order decay (integrated rate law for second order reactions): where N0 is the original quantity, N is the modified quantity, t is time and λ is the decay constant. 𝜆 = 𝜆0 ∗ 𝑒𝑥𝑝 (−𝐸𝑎𝑘𝑇) (3.4) Equation 3.4 – Decay constant (same form as integrated rate law for first order reactions): Where λ0 is the pre-exponential term, Ea is the activation energy, T is temperature and k is the Boltzmann constant. Table 3.2 – Activation energy of select silicon-vacancy defects. Center Activation Energy (eV) Reference H′1 0.37 Nilges et al. 2009 H′2 0.84 Pan et al. 2008 H′3 (I) 0.9 Pan et al. 2009 H′3 (II) 1.9 Pan et al. 2009 H′7 (III) 1.25 Nilges et al. 2008 3.2.2. Oxygen-Vacancy Defects Oxygen vacancies can trap electrons, forming a variety of E defects (Alessi et al. 2014). Of these defects, E′1 is by far the most prevalent, appearing in all quartz EPR spectra from the Athabasca Basin with a relatively small linewidth and Zeeman splitting, leading to an intense signal. E′1 is more easily power saturated than the silicon-vacancy defects, allowing it to be detected at low powers (e.g. 0.02 mW) with minimal interference from silicon-vacancy defects. The g-values of E′1 are close to the free electron value (ge = 2.00232) with relatively little Zeeman splitting, which also reduces interference from other centers which are prominent at low powers. These characteristics along with well established g-matrices make it useful for 18 determining crystal alignment in single-crystal EPR experiments (Nilges et al. 2008, 2009; Pan et al. 2008, 2009). The configuration of E′1 is still controversial, as discussed in the review paper by Alessi et al. (2014). The most widely accepted model involves a positively charged oxygen vacancy, V(O)+, in which the longer bond length Si, Si-O(>), is significantly relaxed and forms a puckered configuration shifted along a plane parallel to its basal oxygen, where it bonds to another oxygen (now a threefold coordinated oxygen). The shorter bond, Si-O(<), shifts towards the vacancy and the spin is localized on this Si atom (Feigl et al. 1974). A tri-vacancy model featuring vacancies for two O and one Si with a nearby Al impurity has also been proposed, which best reproduces all hyperfine and superhyperfine structures measured by EPR experiments (Mashkovtsev et al. 2013) and accounts for the correlation between Al and E′1 centers (Li and Pan 2012). 3.2.3. Aluminum-related Defects Aluminum commonly substitutes for Si, and is often accompanied by a charge balancing monovalent cation such as H+, Li+ or Na+, forming diamagnetic [AlO4/M+]0 defects (Botis and Pan 2009, (Botis and Pan 2009)). Irradiation at temperatures greater than 200K mobilizes the charge-compensating alkali-metal cations, allowing them to diffuse along the channels in the quartz lattice (parallel to the c-axis), and the paramagnetic [AlO4]0 centers are formed once an electron is removed during irradiation (Markes and Halliburton 1979). The [AlO4]0 center, which is detectable only at below 120 K, involves relaxation line broadening at higher temperatures and becomes undetectable at room temperature, is annealed at 300°C. 3.3. Distribution of Paramagnetic Defects in Quartz from the Athabasca Basin The spatial distribution of paramagnetic defects within quartz crystals have been linked to growth and fluid history as well as radiation type. Radiation induced defects in Athabasca Basin sandstones have been observed using cathodoluminescence (CL) imaging to be concentrated at the margins of grains, along fractures and surrounding uranium-bearing mineral inclusions (Botis et al. 2006; Cerin et al. 2017). Areas with high CL intensity were distributed similarly to EPR-active silicon-vacancy defects, despite the greater thermal stability of CL-active defects (Botis et al. 2005, Hu et al. 2008). The 30 – 50 μm thickness (35-45μm Botis et al. 2005, 30-50μm by 19 Cerin 2017) of CL-active rims and halos around inclusions is consistent with modelled penetration distances of α-radiation from the 238U and 232Th decay chains in quartz (Owen 1988), and experiments confirm the development of CL-active halos using He+ implantation (Komuro et al. 2002; Krickl et al. 2008). Partial hydrofluoric acid digestion experiments indicate that the CL-active halos also contain highly elevated concentrations of EPR-active silicon vacancy defects, suggesting they are also primarily formed by α-irradiation. The limited penetration distance of α-radiation can constrain α-induced defects to the exterior of the quartz crystal if exposed to an external radiation source, such as uranium-bearing fluid. However, drusy quartz with uniformly high concentrations of silicon-vacancy defects and low uranium concentrations in the host rocks have also been found in the Athabasca Basin, suggesting radiation exposure throughout growth (Hu et al. 2008, Botis et al. 2008, Cerin et al. 2017). In contrast, the oxygen-vacancy defect E′1 was found to be uniformly distributed (Botis et al. 2006, Hu et al. 2008) suggesting formation due to γ-irradiation, which is more penetrative. E′1 was also found to be correlated with silicon vacancy defects (Cerin et al. 2017), consistent with the main γ-source also emitting α-particles (e.g. 238U). Calculated dose rates from clay samples in the Shea Creek area indicated the dosage from radionuclides present in the sample was mainly controlled by uranium contents (Allard et al. 2018), and in general the contribution of γ-radiation from 40K is expected to be minimal due to the low dose rate, in addition to the relatively low clay content (< 3%) of most sandstones units (Jefferson et al. 2007). The dose rate of γ-radiation from potassium is only 0.202 Gy/ka per 1 wt% K2O (Nambi and Aitken 1986), compared to that of uranium (0.1136 Gy/ka per ppm) and thorium (0.0521 Gy/ka per ppm), and therefore is expected to make minor contributions to γ-dosage given the geochemistry of samples taken near the unconformity, and are very minor relative to α-particle dose rates. The timing of overgrowths determines which generations of quartz are exposed to α-radiation from external sources, and the type of quartz may partially control which defects develop from irradiation. Detrital quartz was derived from many different source terrains, but is expected to be mostly metamorphic or high-temperature igneous in origin, and contain more intrinsic defects than hydrothermal overgrowths formed at low temperatures (Botis et al. 2006). Detrital quartz grains from Athabasca Basin sandstones consistently contain H′3 centers (Cerin et al. 2017) and the spectra typically feature a broad unknown peak at g = 2.035 (Hu et al. 2008). Subsequent generations of quartz overgrowths (e.g. Q2, Q3 etc.) tend to form drusy crystals in 20 voids created by dissolution (Jefferson et al. 2007), and do not contain H′3 centers in some localities such as the Arrow Deposit (Cerin et al. 2017) or a broad peak at 2.035 (e.g. Hu et al. 2008, Cerin 2017). The H′3 center was found to regenerate with neutron irradiation after annealing in detrital but not drusy quartz, suggesting precursor defects are necessary for the development of this defect (Cerin et al. 2017). The main mineralizing events occurred after the development of Q1 (e.g. Kotzer and Kyser 1995, Jefferson et al. 2007), however uranium-bearing minerals commonly occur between detrital grains and Q1 overgrowths suggesting earlier exposure (Botis et al. 2006). CL-active halos have been observed on detrital grains as well as Q1 and Q2 overgrowths (Botis et al. 2006), which suggests all generations of quartz have potentially been exposed to uranium-bearing fluids. Dissolution of the exterior of quartz grains by desilicification is expected to remove most of the α-RID, and can create voids for the growth of subsequent quartz generations (Q2 & Q3), which tend to form as druses in fractures and vugs.21 Chapter 4: Sampling, Analytical Methods and Petrography 4.1. Sample SelectionTwo sandstone samples per core were selected from 48 diamond drill holes (figure 4.2), taken as close to the unconformity as possible without sampling the basal conglomerate. All available drill cores stored at the Saskatchewan Geological Survey Core Lab which contain the sandstone-basement unconformity were sampled. Samples were photographed and dose rates were measured using a γ-spectrometer to ensure the sample location did not contain high concentrations of radionuclides. Dose rates varied from 113 – 184 nSv/h, with the exception of sample 003 (I) which was selected as a special sample for being distinctly radioactive at 250 nSv/h. Twenty samples suitable for creation of thin sections were selected, generally avoiding making two from a single drill core (appendix D). General sampling procedure is summarized in figure 4.1. 22 Figure 4.1 – Sampling flow chart summarizing the sampling and analysis procedureDrill core sampling: 2 -3 samples per core with unconformity present, all cores available from SGS subsurface lab (48 total)Thin section preparation: from 20 samples with enough rock from first DDH sampling (not originally intended)Process all samples: Disaggregate, sieve 0.5 -1 mm fraction, hand pick pure quartz separates for all samples (100 samples)Initial single crystal selection: >1 mm sieve size for high defect concentration samples. Preliminary EPR analysesFinal selection: monocrystalline, without twinning, high defect concentration in crystal. Measure rotation plane. (2 crystals)Powder EPR analysis: powder all samples, measure EPR, reprocess contaminated samples (100 samples total) Isochronal annealing on high concentration sample HAR-05 (I)Low temperature EPR: on select high concentration sample and a reference (HAR-05 (I) and MN-07 606.2m))Partial dissolution and EPR, samples with thin section preferentially selected + 2 high concentration samplesGeochemistry: 1 sample per drill core, only sampling rock fragments (47 samples) 23 Figure 4.2 – Drillhole location map. Legend: MC = McFarlane Group (c = Carswell, d = Douglas, o = Otherside formations with od = Davy, ob = Birkbeck, oa = Archibald members, ll = Locker Lake formation with llm = Marsin, llb = Brundell, lls = Snare members, W = Wolverine Point Group, LL = Lazenby Lake group (l = Larter, s = Shiels), MF = Manitou Falls Group with cl-d = Clampitt-Dunlop, h = Hodge, w = Warnes, b = Bird and r = Read formations, FP = Fair Point Group, dd = Diabase dykes and sills, cb = crystalline basement. (Saskatchewan Ministry of Energy and Resources 2022) 4.1.1. Single Crystal Selection Single crystals were selected from sample 003 (I) based on the powder spectrum containing the same paramagnetic defects as most detrital samples, but in much greater concentrations. Notably, sample 003 (I) was the only sample that was distinctly radioactive, and γ-spectrometer assays indicate Th enrichment in the sample. The largest inclusion free detrital grains were selected for preliminary single crystal EPR analysis to eliminate grains of twinned or composite intergrowth, insufficient defect concentrations, or a spectrum with an irregular baseline suggesting contamination. The large single crystal discussed in the results section was powdered for comparison with other powder samples, but using a greater field modulation amplitude of 2.0 G to acquire enough signal from the small amount of material. 4.1.2. Reference Samples A set of sandstone samples with published spectra were reanalyzed to provide reference to defect concentrations in previous studies (Botis et al. 2016; Pan et al. 2013; Cerin et al. 2017). To facilitate direct comparison, the samples were prepared again from the original rock samples using the same procedure as other samples in this thesis. Reference Sample Descriptions: 2502096 (or AR-14-25 – 96m): Sandstone sample from the Arrow Deposit project with the greatest intensity measured, published in Cerin et al. 2017 (peak amplitude ~101 *103 a.u.) 4002098 (or AR-15-40 – 98m): Sandstone sample from the Arrow Deposit (Cerin 2017) with a previously measured spectra that displayed low intensity (peak amplitude of ~12*103 a.u., one of the lowest concentration sandstone samples analyzed from the Arrow Deposit) MAC135 – 416m: Mineralized sandstone sample from McArthur River, described as displaying abundant radiation-induced defects by Botis et al. 2006. 25 MAC135 – 386m: Sandstone sample from clay alteration zone at McArthur River described as low intensity by Botis et al. 2006. The published spectrum was approximately one order of magnitude lower in intensity than the 416m spectra. WR-194 – 344m: Sandstone sample from Wheeler River core measured along with the Maw Zone study by Pan et al. 2013. The defect concentration is slightly greater than in nearby drill cores (e.g. ZQ-15 and 85-02), and samples collected at greater depths near the unconformity are noted to contain elevated defect concentrations. The two core samples from MAC135, 386m and 416m, were found to have very similar spectra despite previous measurements indicating low defect concentrations in the 386m sample (the gint amplitude of 386m was 14% greater than 416m rather than an order of magnitude less). Similarly, sample 4002098 was expected to have a gint amplitude slightly more than an order of magnitude less than the highest concentration sample, 2502096, but was instead found to have only 52% less. In both cases, the high signal/noise ratio of the expected low concentration samples suggests that these reprocessed samples have greater concentrations than the original measurements. This may be a consequence of the sample heterogeneity or due to differences in sample preparation technique, such as greater preservation of overgrowths. 4.2. Procedure 4.2.1. Sample Preparation and EPR Analysis All measurements were taken at X-band frequencies on a Bruker EMX EPR spectrometer with an ER 4119 HS cavity. A standard of quartz powder containing similar defects (MN-07 606.2m from Hu et al. 2008) was run before measurement to correct for changes in the signal intensity due to spectrometer configuration, and the stability of the measurements was verified afterwards when needed. The standard was prepared twice to ensure changes in the powder volume due to settling did not change the intensity. Rock samples were disaggregated by tapping them with a hammer, and the pieces were then placed in an ultrasonic bath to disaggregate them more completely and remove clay and iron-oxides/hydroxides. The ultrasonic bath was used for approximately an hour on average and 26 rarely longer than 2 hours to avoid rounding the quartz grains or otherwise damaging overgrowths (e.g. Savage 1969). A duplicate preparation of sample LA0-5 (I), which contains thin, fragile euhedral overgrowths projecting from some quartz grains, was performed using a 15 minute duration in the ultrasonic bath vs. 55 minutes, and did not result in substantially different powder EPR spectra. This suggests that short periods in the ultrasonic bath are not problematic when combined with hand picking, as defects were shown to be concentrated externally in this sample using partial HF digestion. The samples were passed through 1000 – 500μm sieves to select the coarse sand fraction, and then picked under a binocular microscope to avoid fragments, grains with visible inclusions and as much remaining clay contamination as possible. Radiation-induced defects in relatively small amounts of clay minerals can dominate the EPR spectrum if present (e.g. from CLU-30-80 in appendix A). Approximately 150 – 200 mg of quartz separates was powdered per sample and ~100 mg was used per analysis. Powdered quartz samples were measured at microwave attenuations of 5 and 10 dB (63 and 20 mW respectively) to record H′ defects, and 20 dB microwave attenuation (2 mW) to include E′1. The scan range was centered to include the gmax of H′3 defects around g = 2.052 and the baseline following the common gmin of the H′ defects at g ~ 2.002. A relatively low field modulation amplitude of 0.8 G with 100 kHz modulation frequency and high spectral resolution (e.g. 0.08 G) was used, although increasing the modulation amplitude at high microwave powers was not observed to result in a loss of resolution or significant distortion of the EPR signals of the H′ defects. A time constant of 40.96 ms was used with a conversion time of 57.51 ms (i.e. very little analog filtering). Single crystals were measured at a field modulation amplitude of 0.10 G for the E′1 signal and 0.80 G for the H′ centers. Spectral resolutions varied but are high in general (e.g. 1/10 of modulation amplitude), with a time constant lower than the conversion time (i.e. minor analog filtering) and no digital filtering. A microwave power of 0.02 mW (40 dB power attenuation) was used for E′1 measurements, and 2 mW (20 dB) for silicon-vacancy defects. A goniometer was used for rotation of the crystal, at a constant angle interval of 5° per step. 4.2.2. Powder EPR Data Processing 27 The silicon vacancy defects were measured using the height of the gmax peaks, and the peak to peak amplitude of the gint ~ 2.007 was taken as a sum of the silicon-vacancy defects. H′2 was taken as the local baseline under the peak at g = 2.035, and the peak at g = 2.035 was measured at 20 mW to subtract H′2. The signal at 2.017 was taken as a peak to peak amplitude, and a local baseline was not used for the data displayed in figures as it had relatively little influence overall. The gint amplitude, g = 2.017 amplitude and 2.049 height were measured at 63 mW, and 20 mW measurements of 2.049 were used for comparison with 2.035. E′1 was measured as the depth of the signal taken from the 2 mW measurement, as a lower power measurement (e.g. 0.02 mW) was not recorded for all samples to measure the height of the first integral or the double integral. Integrals were not used in general due to their high sensitivity to the choice of baseline, which is often non-linear and requires interpretation to model. 4.2.3. Single Crystal EPR Data Processing The orientation of two single crystals from sample 003 (I) was determined by comparison of the angular variation in the line position of E′1 sites to roadmaps simulated using the spin Hamiltonian from Mashkovtsev and Pan (2013). This allowed the site assignments to be determined, and the line position of the sites fit using the angular correction function in the EPR-NMR v. 6.51 computer program (Weil 2003) to determine the crystallographic orientation. The angular correction function fits Euler angles to determine the initial direction and rotation axis. The E′1 angular correction of the crystal displayed in this thesis had uncertainties of 0.20°, 0.15° and 0.15° for the α, β and γ Euler angles respectively, with a line position root mean squared deviation (RMSD) of 0.04(4)G. The rotation axis was fit to θ = 87.5°, ϕ = 50.9°, and the approximately c-axis aligned was simulated using a direction of θ = 2.9°, ϕ = 260.6° (figure 4.3). The field correction was first estimated by comparison and then adjusted by minimization of the line position deviation. The spectra measuring silicon-vacancy defects were normalized to a particular microwave frequency, and site line position roadmaps of known defects were simulated using the data in table 3.1 and overlain upon experimental spectra to identify individual defects. 28 Figure 4.3 – Comparison of experimental E′1 line positions with roadmaps simulated using the orientation from the angular correction fit. The magnetic field is approximately parallel to the crystallographic c-axis at 95°. 4.2.4. Powder EPR Simulations Powder simulations were completed using the program EPR-NMR program (v. 6.51) using the defects in table 3.1. Linewidths were estimated based on visual comparison of powder simulations to experimental powder spectra, and the default Lorentzian line-shape was used for all simulations. Nuclear quadrupole matrices were entered as 0 when not available for defects with known nuclear quadrupolar hyperfine interactions. 4.2.5. Isochronal Annealing Isochronal annealing was performed on a powder from sample HAR-05 (I) from 0 – 600 °C at 100 °C temperature intervals with temperatures maintained for 30 minutes. Each annealing step was performed using a different fraction of powder for ease of measurement. 4.2.6. Microwave Power Response 34753476347734780 20 40 60 80 100 120 140 160 180Line Position (G)Angle of Rotation (°) 29 Samples were measured at 63, 20, 2 and in some cases 0.2 mW, corresponding to 5, 10, 20 and 30 dB of microwave attenuation respectively (200 mW unattenuated source). 4.2.7. Low Temperature Low temperature spectra were acquired from powder samples MN-07 606.2m and HAR-05 (I) using liquid He2 and N2 respectively. MN-07 606.2m is not displayed as the spectra have a lower signal to noise ratio, and responded to temperature the same way as HAR-05 (I). 4.2.8. Geochemistry Whole rock analyses by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectroscopy (ICP-OES) were provided by the Saskatchewan Research Council (SRC) Geoanalytical Laboratory using HF:HNO3:HClO4 total digestion and lithium metaborate fusion for trace and major elements respectively. The lower limits of detection for U, Th and K2O were 0.01 ppm, 0.01 ppm and 0.002% respectively, with a relative standard deviation (RSD) of ≤ 1.0%. Rock fragments were sampled to ensure the clay matrix was included, and a single rock sample was selected from all drill cores excluding HAR-01, which only had loose sediment available and was therefore unrepresentative. 4.2.9. Partial Dissolution Selected samples of hand picked quartz sands were partially dissolved by submersion in 20M HF solution for 2 – 8 hours. Partially dissolved samples were inspected under a binocular microscope, and these observations were combined with the number of grains and appearance of the sample to qualitatively estimate the amount of fragmentation, which could cause the interior to be dissolved before the exterior. Samples with insufficient dissolution were submerged again in fresh HF. Samples were prepared using the same procedure as all other powder EPR samples (i.e. 100 mg powder, intensity normalized to a standard). 30 The radius removed by dissolution was modelled by approximating the grains (which are typically rounded to well rounded) as spherical and calculating the radius loss for both the maximum and minimum sizes separated by the sieve (1000μm – 500μm diameter). The equation for modelling this is: ∆𝑟 = 𝑟0 − √𝑟03 (1 −𝑚0 − 𝑚1𝑚0)3(4.1) Equation 4.1 – Where ∆𝑟 is change in radius, 𝑟0 is the initial radius (estimated as 500μm to 1000μm corresponding to the sieve size) and 𝑚0 and 𝑚1 are the initial and final masses respectively. The ratio of the gint amplitude of the dissolved portion over the remaining material is calculated using: 𝐴𝑜𝑢𝑡𝑒𝑟𝐴1=𝐴0 − 𝐴1 ∗ (𝑚1𝑚0)(1 −𝑚1𝑚0) ∗ 𝐴1(4.2) Equation 4.2 – Where 𝐴0 and 𝐴1 are the measured initial and final 𝑔 ≅ 2.007 amplitudes respectively, 𝐴𝑜𝑢𝑡𝑒𝑟 is the calculated amplitude of the dissolved portion and 𝑚0 and 𝑚1 are the initial and final masses respectively. 4.3. Core Description and Petrography Sandstones samples were generally medium to coarse grained and well sorted, but very coarse sand and minor amounts of granules were common in some locations (Error! Reference source not found.4). The colour of the core varies from buff to bleached, red, yellow and purple, and is mainly determined by the presence of iron oxides/hydroxides. In hematized drill cores, spotted bleaching and bleaching along fractures was commonly observed, and Liesegang banding (Error! Reference source not found.4c) was also rarely present near the unconformity. Other features such as heavy mineral laminae, thin conglomeratic beds, clay intraclasts and mudstone/siltstone layers were present but not intentionally sampled, and cross bedding was commonly observed. The basal conglomerate occurs directly above the unconformity with variable thickness, ranging from typically less than a meter to absent or unknown due to partial core loss near the unconformity. Crystalline basement rock underlying the unconformity is 31 altered, and often appears hematized, characteristic of the red zone, or bleached by late hydrothermal alteration. Figure 4.4 – Core photographs, downward direction is downhole. a Basal conglomerate and unconformity in AS-001. b Preserved unconformity contact in CLDD-2. c Liesegang banding and spotted bleaching in CR-04. Sandstone near the unconformity varies from well cemented to friable and occasionally completely disaggregated (e.g. figure 4.5d). In thin section the amount of quartz overgrowths and pressure solution at point-to-point contacts between quartz grains varies, and a combination of both results in an interlocked texture in some samples. Two types of syntaxial quartz overgrowths were commonly observed: a thin layer with a dusty appearance from abundant hematite inclusions, and a clear, commonly euhedral generation consistent with Q1. The thickness of the inclusion-rich overgrowths is consistently very thin, often making it difficult to determine whether it is the earlier hematite inclusion rich generation Qa, or hematite inclusions at the interface between the detrital grain and Q1. The clear euhedral overgrowths are typically thicker than the hematite rich overgrowths in the thin sections examined, however they are still 32 somewhat thin other than along the c-axis of euhedral crystals, which can be > 100 μm. The combined overgrowth thickness is highly variable even within individual sections, and overgrowths were not observed in two sections. Measurements were taken at approximately representative locations throughout the thin sections, and the average overgrowth thickness in any section did not exceed 40 μm, thinner than reports of thick early overgrowths up to 250 μm (e.g. Hiatt et al. 2007). Pressure solution textures such as sutured or convex-concave contacts were commonly observed. Minor amounts of quartz dissolution was also observed in most thin sections, resulting in highly irregular, pitted grain surfaces filled with fine grained clay, consistent with descriptions of dickite replacement of quartz (Hiatt and Kyser 2007). Sand grains consist almost entirely of detrital quartz, with minor amounts of lithic fragments and clay pseudomorphs, likely from the alteration of detrital feldspars. Both monocrystalline and polycrystalline quartz grains are common, and polycrystalline grains appear to become more common with increasing grain size. Strain and recrystallization textures such as undulose extinction, subgrain rotation, bulging and sutured boundaries were common in all sections, and inclusions of rutile, zircon and biotite were also common. Accessory minerals include zircon and muscovite, which are expected to be detrital, as well as coarse grained chlorite and tourmaline (tourmaline was noted in eleven sections). Pore spaces are filled almost exclusively with interstitial clays and were not examined in detail. 33 Figure 4.5 – a) Syntaxial overgrowths on detrital quartz from DDH 2 (Ensign), XPL. b) Pressure solution textures in DDH 2 (Ensign), XPL. c) Irregular grain boundaries from quartz dissolution in SHE3-3, PPL. d) Example of friable sandstone from CLU-30-80, sandstone ends slightly below 320’ marker. a. b. c. d. 34 Chapter 5: Powder EPR Spectra 5.1. Introduction Powder EPR spectra of detrital quartz contain combinations of silicon and oxygen vacancy defects similar to those previously found in detrital quartz in the Athabasca Basin (e.g. Botis et al. 2006, Hu et al. 2008, Cerin et al. 2017). H′3 and E′1 were found in all analyses, and prominent peaks at 2.035 and 2.017 with a low intensity H′2 signal were very common also. It is expected that H′2 would be prominent in many of the spectra if the defect had less 27Al hyperfine splitting (~15 G wide multiplet). H′4 also has relatively strong hyperfine splitting (> 20 G wide multiplet in powder simulations), but it was not clearly observed despite being reported as a common signal in detrital quartz by Cerin (2017). In contrast, H′1 and H′7 (III) have relatively little hyperfine splitting (~ 2 G peak width) but are not prominent, and generally appear as small peaks only distinct at lower microwave powers (e.g. 2 mW), due to being in passage at greater microwave powers. 5.2. Powder EPR Simulations Some combinations of defects appear to be simulated well (e.g. figure 5.1), however there are some discrepancies even in the range of silicon vacancy gmax values. Two overlapped peaks are often present at g ≅ 2.049 (e.g. figure 5.3), and although simulations of H′3(I) were consistent with the peak position, simulations of H′3(II) were not (e.g. figure 5.2). However, at low temperature 27Al hyperfine splitting becomes resolved at the expected g-values, confirming a combination of H′3(I) and H′3(II), which is also consistent with single crystal analyses. 35 Figure 5.1 – Comparison of experimental and simulated powder EPR spectrum of sample DV10-001 (I) at low microwave power. Defects are simulated from data in table 3.1, including E′1, H′1, H′2, H′3, H′7 (II), H′7(III) and #3. Powder EPR simulations of known defects did not reproduce the prominent peak which is characteristic of detrital quartz at g = 2.035 (Hu et al. 2008). This g-value is very similar to the gmax of H′2, but it lacks prominent hyperfine splitting and appears as a single peak (Pan et al. 2013). The signal around g ≅ 2.017 is also very common and prominent in sandstone samples from the Athabasca Basin, but was also not reproduced by simulations of H′7(I) and (II), which both have similar gmax values and significant hyperfine splitting (e.g. H′7(II) has a ~ 7 G wide multiplet in simulations), unlike H′7(III). The peak appears to drop below the baseline at g = 2.017 in samples with high concentrations of this defect, and resembles the first derivative of a peak rather than that of the gmax of an anisotropic defect. In low concentration samples, the negative portion on the high field side of the peak is reduced by the common gint at approximately 2.007. Simulation of a single rhombic defect with hypothetical g-factors approximated as gmax = 2.035, gint = 2.017 and gmin = 2.003 match both the features at g = 2.035 and g ≅ 2.017 (figure 5.2). To evaluate the possibility of these two peaks being attributable to a single defect, the 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueExperimentalSimulatedP = 2 mW H′3H′2H′7E′1#3H′1 36 power response, thermal stability, behaviour at low temperature and correlations between defects were evaluated to attempt to differentiate the two peaks as two separate defects. A single crystal was also analyzed to attempt to isolate individual defects and thereby better interpret the powder spectrum of the analyzed crystal. Figure 5.2 – Comparison of experimental and simulated powder EPR spectrum of sample CLC13-066 (II), including a hypothetical rhombic defect to simulate the features at both g = 2.035 and g = 2.017. 5.3. Defect Properties and Associations 5.3.1. Power Saturation and Low Temperature Analyses Differences in power saturation behaviour between defects can differentiate them, and the power response also indicates the appropriate power for measuring individual centers. The peaks 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueExperimentalSimulatedP = 2 mW 37 at g = 2.035 and g ≅ 2.017 have a similar power response at room temperature, and do not begin to noticeably broaden even at high power (figure 5.3). Figure 5.3 – Power response of 003 (I). At low temperatures the peaks become increasingly broadened with reduction in temperature. Linewidth broadening of the peaks at g = 2.035 and g ≅ 2.017 occurs below 150 K (figure 5.4), shown at a microwave power of 2 mW. At 90 K for the peak at g = 2.035 is unrecognizable, and the signal at g ≅ 2.017 is obscured at 90 K by the appearance of [AlO4]0. [AlO4]0 with strong linewidth broadening contributes to the 110 K spectra at the g ≅ 2.017 range; linewidth broadening and disappearance of the [AlO4]0 signal at greater temperature is expected, potentially due to electron hole hopping (Walsby et al. 2003). The temperature response was replicated with sample MN-07 606.2m, a low defect concentration detrital quartz sample from Hu et al. (2008), which was measured using liquid He2 and behaved the same as sample 003 (I). 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-value2 mW20 mW63 mW0.2 mW 38 Figure 5.4 – Low temperature powder EPR spectra of sample HAR-05 (I) showing the [AlO4]0 center. In measurements by Pan et al. (2008), H′2 and H′7(II) were in passage with microwave power ≥ 6.3 mW at X-band frequencies, and the peaks were not broad with 2 mW at 110 K. H′1 has also been measured at temperatures as low as 77 K (Nilges et al. 2009). However, microwave power response is not directly comparable between different experimental configurations and samples (e.g. dependence on cavity Q factor, concentration dependence on relaxation kinetics), however it is notable that strong linewidth broadening was observed even with a microwave power of 0.2 mW in this study. The low temperature measurements also indicate that the peaks have the same response to low temperature, and are not able to be differentiated by their power response. The hyperfine splitting of H′3 is resolved at low temperature, but the signal does not change notably over the 150 – 90 K temperature range, and similarly, the amplitude and structure of the gint at g ≅ 2.007 also does not change significantly over this temperature range. Three peaks centered around g ≅ 2.060 increase in intensity over the 150 – 110 K range, possibly 1.9922.012.022.032.042.052.062.07Intensity (a.u.)g-valueP = 2 mW 150 K130 K120 K110 K90 K 39 attributable to H′6 (#7) (Pan et al. 2008), another silicon vacancy defect only detectable at low temperature, however this defect is not expected to display hyperfine splitting. The lack of change at g ≅ 2.007 despite the much more prominent peaks at g = 2.035 and g ≅ 2.017 broadening and disappearing was not expected, as both these peaks are expected to arise from defects with gint near this position, and therefore make large contributions to this signal. Figure 5.5 – Expansion of figure 5.4, highlighting the g = 2.01 – 2.04 region (a) and H′3 (b). Additionally, the two signals at g = 2.008 and 2.006 in figure 5.3 are still present at low microwave power, and may belong the center #3 (Götze et al. 2015b), but with slightly different effective g-values than originally reported in Mashkovtsev et al. 1978. This center may also be included in the measurement of the common gint of the silicon vacancy centers at low microwave power, and there is notable similarity in the peak shape between low and high power measurements, possibly indicating only partial saturation at high microwave power. Partial saturation also occurs at high microwave power (figure 5.6) for centers H′1 and H′7(III), as well as H′2 to a lesser extent, causing other common centers such as H′3 and the main features at g = 2.035 and g ≅ 2.017 in powder spectra to become relatively more prominent at high microwave power and therefore overrepresented in measurements. a. b. 40 Figure 5.6 – Power response of LA0-5 (I). 5.3.2. Thermal Annealing Differences in thermal stability between defects can also be used to distinguish different defects by their response, as well as isolate the more thermally stable defects. The concentration dependence of second order decay prevents comparison to previous studies without a common standard, however the activation energy is a constant (table 3.1). The low temperature annealing steps at 100 – 200 °C did not increase the signal intensity (figure 5.7), in contrast to the results of Botis (2005). The peaks at g = 2.035 and g ≅ 2.017 both began annealing at 400 °C, and annealed at similar rates at the 500°C step, and were completely annealed at 600 °C, therefore not differentiating the two peaks (figure 5.8). H′3 began annealing distinctly at 500 °C, and was completely annealed at 600 °C. As the peaks at g = 2.035 and g ≅ 2.017 began annealing before H′3, they cannot be isolated by annealing H′3, which is the main source of interference in single crystal EPR analyses. 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-value2 mW20 mW63 mWH′1H′3H′2H′7 (III) 41 Figure 5.7 – Summary of relative intensities of EPR signals in sample HAR-05 (I) as a function of isochronal annealing temperature, normalized to the room temperature measurement. 42 Figure 5.8 – Isochronal annealing of sample HAR-05 (I). 5.3.3. Single Crystal Analyses Two detrital quartz crystals from sample 003 (I) were selected due to their high defect concentrations and analyzed to identify the defects present. Simulations at the approximately c-axis aligned orientation are consistent with the presence of H′1, H′2, H′3, #3, E′1 and low concentrations of H′7(II) (figure 5.9). Roadmaps of the line position variation of prominent silicon-vacancy defects are consistent with H′3(I) and H′3(II), and due to their relatively high concentration the H′3 defects overlap with other silicon-vacancy defects at most orientations. Simulated line position roadmaps of H′1 did not distinctly match the experimental data, and attempts to fit H′1 using the expected site assignments did not produce a meaningful fit. 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueOriginal300 °C400 °C500 °C600 °CP = 20 mW 43 Figure 5.9 – Comparison of experimental and simulated single crystal spectrum from sample 003 (I), with the magnetic field approximately parallel to the crystallographic c-axis (95° in Figure 5.10). Simulated centers are labelled, and square brackets indicate the width of hyperfine splitting. 1.981.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueExperimentalSimulatedP = 2 mWE′1#3H′3H′7H′1H′2 44 Figure 5.10 - Simulated roadmap of H′3 (II) overlain upon the experimental single crystal spectra. Figure 5.11 - Simulated roadmap of H′1 overlain upon the experimental single crystal spectra. -1001020304050607080901001101201301401501601701801903350 3360 3370 3380 3390 3400 3410 3420 3430 3440Angle (°)Magnetic Field (G)Experimental spectra Simulated line position roadmaps-1001020304050607080901001101201301401501601701801903350 3360 3370 3380 3390 3400 3410 3420 3430 3440Angle (°)Magnetic Field (G)Experimental spectra Simulated line position roadmaps 45 High power (63 mW) EPR spectra of the single crystal powder contain the same signals as the rock sample powder analysis in different proportions (figure 5.12). H′1 is not observed despite appearing to be one of the most prominent silicon vacancy defects in the single crystal analysis. The absence of H′1 in the powder analysis and presence of an unknown peak at g = 2.035 may suggest that the peak assumed to be H′1 in this single crystal analysis is a different center. H′2 is not apparent in the powder spectra despite its presence in the single crystal analyses, which is likely due to its low concentration, relatively large 27Al hyperfine splitting and partial power saturation, as a relatively high power (63 mW) was required to acquire enough signal. Figure 5.12 – Powder spectra from sample 003 (I) of a the single crystal and b the entire sample (greater sample mass). 5.3.4. Defect Associations The H′3 center is correlated (R2 = 0.85) to the common measure of silicon-vacancy defects at g = 2.007 (figure 5.13), unlike the other prominent peaks at g = 2.035 and 2.017 (figure 5.15, figure 5.16), which are not correlated in samples with high concentrations of these defects. However, the intensity of the g = 2.035 and g ≅ 2.017 peaks are correlated (R2 = 0.95) to each other (figure 5.14). H′3 and the peaks at g ≅ 2.017 and g = 2.035 are commonly the most 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueP = 63 mW 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueP = 63 mW a b 46 prominent gmax peaks, making the correlations consistent with H′3 frequently making the greatest contribution to the amplitude of the gint = 2.007, and the peaks at g = 2.035 and 2.017 being correlated with each other but independent to H′3. A positive correlation between g = 2.035 or 2.017 with the gint amplitude was not observed despite their high proportion in many spectra. Spectra with high proportions of g = 2.035 and 2.017, for example samples 003 (I) (figure 5.12b) and HAR-05 (figure 5.3), have unexceptional gint amplitudes and plot in similar locations on graphs of 2.007 vs 2.035 and 2.049 vs. 2.035, despite the expectation of large contributions to the gint ≅ 2.007 amplitude from the high proportions of peaks at g = 2.035 and g = 2.017. E′1 is positively correlated to with H′ defects throughout the Athabasca Basin (figure 5.17), similar to the correlation found surrounding the Arrow Deposit (Cerin et al. 2017), although the exponential fit is not displayed here for the sake of consistency. Figure 5.13 – Height of g = 2.049 peak attributable to H′3 vs. the peak to peak amplitude of the gint common to silicon vacancy defects. R² = 0.84790246810120 0.2 0.4 0.6 0.8 1g= 2.007 Amplitude (a.u.)g = 2.049 Height (a.u.) 47 Figure 5.14 - The peak to peak amplitude of the signal at g = 2.017 vs. the peak height at 2.035. Figure 5.15 - The height of the peak at g = 2.035 vs. the peak to peak amplitude of the gint common to silicon-vacancy defects. Notable samples with relatively high concentrations of g = 2.035 are labelled. R² = 0.947200.20.40.60.811.21.41.61.820 0.1 0.2 0.3 0.4 0.5 0.6 0.7g= 2.017 Amplitude (a.u.) g = 2.035 Height (a.u.)HAR-05 (I)HAR-05 (II)003 (I)0246810120 0.2 0.4 0.6 0.8 1g = 2.007 Amplitude (a.u.)g = 2.035 Height (a.u.) 48 Figure 5.16 - Height of g = 2.049 peak attributable to H′3 vs. the height of the peak at 2.035, both measured at 10 dB. Notable samples with relatively high concentrations of g = 2.035 are labelled. Figure 5.17 - The peak to peak amplitude of the signal at g = 2.007, attributed to the common gint of silicon vacancy defects vs. the peak height at 2.035. HAR-05 (I)HAR-05 (II)003 (I)00.10.20.30.40.50.60.70 0.2 0.4 0.6 0.8 1g= 2.049 Height (a.u.)g = 2.035 Height (a.u.) 12345678910110 1 2 3 4 5 6 7g= 2.007 Amplitude (a.u.)g = 2.0002 Depth (a.u.) 49 5.3.5. Summary Power saturation, temperature response and thermal annealing experiments showed a similar response for the peaks at g = 2.017 and g = 2.035. These two peaks occur together in a relatively consistent ratio (figure 5.14), and this ratio is expected to be more consistent if the influence of underlying peaks could be more effectively removed, particularly around g = 2.017. High proportions of both g = 2.035 and g = 2.017 relative to the other common silicon-vacancy defect, H′3, do not correlate well with the g = 2.007 amplitude, which is the common gint amongst silicon vacancy defects (figure 5.15, figure 5.16). Additionally, the g = 2.007 signal does not change distinctly with the broadening of the signals at both g = 2.035 and g = 2.017 at low temperature, despite a relatively large proportion of these defects in the samples analyzed. Analyses of a single crystal containing these two signals are inconclusive due to the high proportion of H′3 which was observed in all samples, and the signals of interest cannot be isolated by annealing due to the greater thermal stability of H′3. The same peaks are observed in the absence of H′3 in other locations, e.g. samples AStE in Götze et al. (2015) and StE1 in Götze et al. (2015a) from St. Egidien, Germany. All properties and associations are consistent with both peaks being attributed to a single defect, and powder simulations of a single defect match experimental spectra, however without single crystal data this cannot be substantiated, especially considering the substantial deviation from known gint values for oxygen radicals. The peak at g = 2.035 has previously been noted to commonly occur in detrital quartz, and consistently cooccurs with the signal at g = 2.017 in published data (e.g. Botis 2005, Hu et al. 2008, Pan et al. 2013, Cerin 2017), which is also not well simulated in powder spectra by known defects with similar gmax values. Neither of these peaks are observed in powder spectra from drusy quartz in Hu et al. (2008) or the various types of drusy quartz including clear, milky, smoky, pink varieties data from supplemental data from Cerin (2017) (n = 76, including some contaminated spectra). This suggests that these peaks may be absent in drusy quartz from the Athabasca Basin, but very common in detrital quartz of sandstones. 50 Chapter 6: Distribution of RID and Evidence for Basin-Wide Uranium-Bearing Fluids 6.1. Overview Radiation-induced defects were detected in all sandstone samples taken at the unconformity, with more than an order of magnitude of variation in the gint amplitude representative of “all” silicon vacancy defects (figure 6.1, appendix C). For comparison, a selection of reference sandstone samples from the Arrow, McArthur River and the Maw Zone area were analyzed. These references included the sandstone sample with the greatest defect concentration measured from the Arrow deposit area (2502096) by Cerin (2017), a sample near mineralization at McArthur River (MAC135 - 416m) from Botis (2005), as well as lower concentration samples from these areas and near the Maw Zone. Reference samples contained defect concentrations within the range of unconformity samples, and were lower than many of the high concentration samples. The original rock samples were processed using the same procedure as all other samples in this project, and the defect concentrations in the powder samples may therefore differ from those used in the original measurements (as described in 4.1.2). 51 Figure 6.1 – Comparison of the gint amplitude of unconformity samples from this project with references and measurements before and after partial dissolution of select samples. Data on the stratigraphy directly overlying the unconformity were available for 32 drill cores through the Saskatchewan Geological Survey GeoAtlas, and include the Fair Point, Read, Smart and Bird (formerly MFb) formations. Sandstone samples from all the basal formations developed similar combinations of paramagnetic defects, and there were no prominent differences in gint intensity between stratigraphic groups (figure 6.2), although the number of samples is relatively small. Samples from the Th-rich Bird formation did not display greater defect concentrations, which is expected as samples were not selected from the conglomeratic layers which are known to contain elevated Th concentrations (Mwenifumbo and Bernius 2007). 52 Figure 6.2 - Height of g = 2.049 peak attributable to H′3 vs. the peak to peak amplitude of the gint common to silicon vacancy defects, plotted with stratigraphic group indicated. Samples were collected from depths ranging from near surface to about 1.5 km, with deeper samples possibly exposed to greater temperatures, but not exceeding their maximum temperature of thermal stabilities. The radiation-induced defects observed in quartz are expected to be stable up to 280°C (Pan and Hu 2009) and therefore preserved in the Athabasca Basin (Pan et al. 2013). The gint amplitude and defect ratios were plotted against unconformity depth data, and no trend between was observed, consistent with the defects being thermally stable (figure 6.3). 0246810120 0.2 0.4 0.6 0.8 1g= 2.007 Amplitude (a.u.)g = 2.049 Height (a.u.) Fair PointManitou Falls BReadSmart 53 Figure 6.3 - Unconformity depth vs. gint amplitude. Figure 6.4 – Unconformity depth vs. the ratio of the peak heights at g = 2.035 and 2.049. Samples with a high ratio are labelled and correspond to samples with the highest g = 2.035 peak heights highlighted in figure 5.16. 020040060080010001200140016000 2 4 6 8 10 12Unconformity Depth (m)g = 2.007 Amplitude 003HAR-05HAR-05020040060080010001200140016000 0.5 1 1.5 2 2.5 3Unconformity Depth (m)g = 2.035/2.049 Peak Height Ratio 54 6.2. Geochemistry Geochemical analyses were performed on a single sample per core for 47 of 48 drill core samples analyzed in this project (appendix B). Sandstone samples were dominantly quartz with an average of 92.6% SiO2, therefore no correction was made for the clay content of the sample. No correlation between U or Th with the g = 2.007 amplitude was observed (figure 6.5, figure 6.6), and both samples with high defect concentrations but low concentrations of radiogenic elements as well as samples with relatively high concentrations of radiogenic elements but low defect concentrations were present. Modelled α-particle dose rates from U and Th contents were also calculated using constant modern dose rates of 2.781 and 0.739 Gy/ka per ppm for U and Th respectively with no Rn loss (Nambi and Aitken 1986). A correlation between silicon-vacancy defect concentrations and dose rate is not observed, consistent with exposure to other sources of radiation. Figure 6.5 – Amplitude of the signal at g = 2.007, attributed to the common gint of silicon vacancy defects vs. the uranium concentration. 01234560 10 20 30 40 50g= 2.007 Amplitude (a.u.)Uranium (ppm) 55 Figure 6.6 – Amplitude of the signal at g = 2.007, attributed to the common gint of silicon vacancy defects vs. the thorium concentration. Figure 6.7 – Amplitude of the signal at g = 2.007, attributed to the common gint of silicon vacancy defects vs. the modelled dose rate. 01234560 0.5 1 1.5 2 2.5g= 2.007 Amplitude (a.u.)Thorium (ppm)01234560 10 20 30 40 50g= 2.007 Amplitude (a.u.)Dose Rate (Gy/ka) 56 6.3. Partial Dissolution Quartz sands from a selection of samples were partially dissolved in HF acid to determine the distribution of silicon vacancy defects in the underlying detrital grains and secondary overgrowths where present. The interior of the sand grains was expected to preserve background concentrations of silicon vacancy defects due to the limited ~30 – 50 μm penetration distance of α-radiation in quartz. The radius removed by dissolution was modelled based on mass reduction (table 6.1) and is predicted to exceed the α-particle penetration distances from the current exterior of the crystal. Samples with typical defect concentrations, including CAR-114 (I), P9-81-02 (II) and 2 (I), were reduced to the lowest concentrations measured in this project after partial dissolution. Only one undissolved sample contained greater defect concentrations than DGS-07 (I) after partial dissolution. The minimal concentrations of defects present in the interior suggest that the defect concentrations present in the original detrital material are low, and therefore do not contain most of the defects despite forming a large portion of the sample mass. However, the high concentration samples (HAR-05 (I) and LA0-5 (I)) still contained defect concentrations similar to many undissolved samples, despite a large decrease in concentration. Previous cathodoluminescence imaging of sandstones from the McArthur River area by Botis et al. (2005; 2006) revealed irradiation along fractures extending into the grains and along the contacts between detrital grains and secondary overgrowths, providing a potential explanation for the greater than expected concentrations in the interior. Table 6.1 - Change in gint intensity with partial dissolution. ID gint Amplitude (a.u.) Mass Reduction Modelled Radius Reduction (µm) Disintegration Initial Final Concentration Reduction Intensity Ratio Minimum Maximum CAR-114 (I) 1.37 0.51 63% 5.4 39.0% 76 152 Minor HAR-05 (I) 2.84 1.78 37% 5.6 13.0% 23 45 Minor 1.05 63% 4.7 45.6% 92 184 Minor DGS-07 (I) 1.77 0.70 60% 3.8 54.7% 116 232 Major LA0-5 (I) 10.40 1.67 84% 11.9 48.0% 98 196 Minor P9-81-02 (II) 1.28 0.67 48% 6.2 17.6% 31 62 Minor 0.41 68% 5.6 45.6% 92 184 Moderate 2 (I) 1.59 0.43 73% 7.6 40.3% 79 158 Moderate 57 The large reduction in defect concentration with dissolution indicates high concentrations of silicon-vacancy defects in the exterior of the sand grains. Calculations based on mass reduction indicate that the exterior contains 3.8 to 11.9 times the concentration of silicon vacancy defects as the interior, consistent with defects formed by α-radiation from an external source. Two samples were divided for a short and long duration digestion, intended to dissolve the zone of α-radiation penetration in the short dissolution, and extend further into the sand grain with the longer dissolution. The longer digestions removed material expected to be out of the range of α-radiation and caused fragmentation resulting in dissolution of the interior, but despite this the relative defect concentration of the dissolved material remained elevated. This elevated defect concentration extending into the sand grains is also consistent with previous CL observations by Botis et al. 2006 of defects concentrated along fractures and contacts, earlier overgrowths and detrital material, and consistent with the observation of elevated defect concentrations remaining in samples HAR-05 (I) and LA0-5 (I). Figure 6.8 – Partial dissolution of P9-81-02 (II). 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueP = 63 mW Original 8 hours2 hours 58 Figure 6.9 - Partial dissolution of HAR-05. In contrast to previous analyses by Botis et al. (2006) and Hu et al. (2008), E′1 is also concentrated in the exterior in all samples (e.g. figure 6.9), possibly indicating a significant proportion formed from α-radiation, or that E′1 develops at a greater rate in the overgrowths. E′1 has been found to be uniformly distributed and formed by beta and gamma radiation in natural samples (Toyoda et al. 2005), and not by internal α-radiation from U and Th impurities (Rink and Odom 1991, Toyoda et al. 2001). 6.3.1. Overgrowths The limited penetration distance of α-radiation is also expected to concentrate defects in the regional overgrowth generations which predate the main mineralizing events (e.g. Kotzer and Kyser 1995, Jefferson et al. 2007). Two types of overgrowths were commonly observed in thin sections: the first type appearing as a thin layer with a dusty appearance from abundant 1.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueP = 2 mW Original8 hours2 hours 59 inclusions, and clear commonly euhedral overgrowths. Thin, syntaxial overgrowths with many small inclusions are consistent with descriptions of Qa, however Qa has only been reported as being present on the eastern side of the basin in the Manitou Falls group (Hiatt et al. 2007). The limited thickness of the inclusion-rich overgrowths makes it difficult to distinguish between the earlier hematite inclusion rich generation Qa, and hematite inclusions at the interface between the detrital grain and Q1. Clear, euhedral overgrowths are consistent with the Q1 generation which occurs throughout the basin, but other later generations may also have a similar appearance. The thickness of overgrowths varies from absent to hundreds of micrometers, with most sections containing inconsistent thicknesses less than 40 μm, with the inclusion rich overgrows thin relative to Q1. Overgrowths were observed in thin sections of samples CAR-114 (I), DGS-07 (I) and 2 (I) (e.g. figure 6.11), as well as minor and inconsistent overgrowths on samples P9-81-02 (II) and HAR-05 (I) (from a thin section of a sample taken 1.2m away). All these samples (with the exception of sample 2 (I), which appears to have clay contamination) have EPR spectra typical of detrital quartz, and contain the same defects in similar ratios before and after dissolution, suggesting that the overgrowths contain similar types of defects to the detrital core of the crystals in these samples (figure 6.10). However, sample DV10-001 (I) (figure 5.1) does not have significant overgrowths, and the spectra from this location and 1.5 m away have unusual powder EPR spectra featuring H′2 more prominently with a minor amount of the broad peak at g = 2.035, suggesting some differences in the development of defects between detrital grains. 60 Figure 6.10 – Powder EPR spectra of low concentration dissolved samples. In contrast, sample LA0-5 (I) has small drusy overgrowths (figure 6.11b) and contains an uncommon combination of defects, with high concentrations of H′1 and H′7(III) (figure 6.12a) and lacking the features commonly present at g = 2.035 and g = 2.017. This combination of defects is similar to previous analyses of drusy quartz by Hu et al. (2008). Larger drusy quartz crystals are also found in vugs in this sample (figure 6.11 a). Dissolution of the drusy overgrowths leaves the remaining material with a spectrum similar to most detrital quartz (figure 6.12b), possibly indicating that μm-scale overgrowths can control which defects develop from irradiation. -3-2-101234561.981.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueOriginalPartially dissolvedP = 63 mWCAR-114 (I)DGS-07 (I)P9-81-02 (II)2 (I) 61 Figure 6.11 – a Drusy quartz in vug from DDH LA0-5, taken about 3.6m from sample LA0-5 (I). b Euhedral overgrowths from sample LA0-5 (I) (scale bar = 1 mm) Figure 6.12 – EPR spectra of LA0-5 (I) a before and after partial dissolution measured at low microwave power and b after partial dissolution, measured at high microwave power. -4-3-2-10121.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueOriginal6 hr partial dissolutionP = 2 mW ′2 ′3E′1 ′1 ′7 (III)-2-1.5-1-0.500.51.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueP = 63 mW b a b a 62 6.4. Evidence for basin-wide uranium-bearing fluids All samples measured in this thesis contain radiation-induced defects in concentrations similar to those previously measured in the Athabasca Basin, including detrital quartz near the Arrow and McArthur River deposits. The lack of correlation between modelled dose rates calculated from sample U and Th contents and the concentration of defects suggests that the defects are not formed primarily due to radionuclides present in the sample. Partial dissolution experiments also indicate that the core of the detrital grains contain relatively low defect concentrations, consistent with α-particle irradiation of the exterior of the grains rather than from internal inclusions or prior exposure during crystal growth of detrital quartz. These features support a temporary source of radiation as responsible for forming these defects, such as a uranium-bearing fluid, which would indicate extensive flow of uranium-rich brines throughout the basin. Basin-wide brine circulation is supported by similar brine compositions at deposits and throughout in the Athabasca Basin (Richard et al. 2015), as well as patterns of quartz dissolution and cementation suggesting basin scale thermal convection (Wang et al. 2021). Uranium concentrations of up to ~600 ppm have been observed in fluid inclusions surrounding uranium deposits (Richard et al. 2010, 2012) indicating high uranium concentrations in the ore forming fluids. Elevated uranium concentrations (0.6 to 26.8 ppm U) relative to typical formation waters are also observed in fluid inclusions entrapped in regional quartz overgrowths (Chi et al. 2019). These inclusion measurements are limited to four drill cores located away from known uranium mineralization, but suggest uranium-rich fluids circulated throughout the basin. However, the concentration of radiation-induced defects in the exterior of the grains, including the overgrowths, and may indicate irradiation continued after the formation of the overgrowths given the limited penetration of α-particles in quartz. The timing of porosity closure by cementation and compaction can reduce permeability and create aquitards that are isolated from later fluid flow (Holk et al. 2003, Hiatt and Kyser 2007). This may partially explain the variation in paramagnetic defect concentrations between nearby samples. 63 Chapter 7: Summary and Future Outlook Radiation-induced defects in diamagnetic host minerals, such as quartz and clay, can be detected and quantified using EPR. This technique has already been applied to select localities throughout the uranium-rich Athabasca Basin, and has revealed various silicon-vacancy defects in quartz correlated with continuous cathodoluminescent halos formed from α-radiation. In this thesis, detrital quartz samples were taken from sandstones directly overlying the sandstone-basement unconformity from 48 diamond drill holes spread throughout the Athabasca Basin. Radiation-induced defects were observed in all samples in similar concentrations to those previously measured in the Athabasca Basin, including sandstone at the Arrow and McArthur River deposits. Partial dissolution experiments indicate that high concentrations of silicon-vacancy defects are limited to the exterior of the detrital grains, while the core contains low paramagnetic defect concentrations. This is consistent with α-particle irradiation, which has limited penetration in quartz, originating from a source external to the grains rather than from internal inclusions. Sample geochemistry was measured to quantify radionuclide concentrations in the sample, and a lack of correlation between modelled dose rates and the concentration of paramagnetic defects suggests that the defects are not formed primarily due to the radionuclides present in the sample. These features support the defects forming from exposure to a temporary source of radiation such as a uranium-bearing fluid. This is consistent with previous reports of extensive flow of uranium-rich brines throughout the basin. As the paramagnetic defects are concentrated in the exterior of the quartz grains, they are expected to be contained within secondary overgrowths and less affected by differences in the underlying detrital quartz. This is supported by the lack of correlations between defect type or concentration with stratigraphic units (known for a limited number of samples). The consistency of defect types also contributes to the comparability of the results and allows defect concentrations to be approximated using the gint amplitude rather than double integration, which is unaffected by defect specific properties such as the magnitude of the hyperfine splitting. The EPR spectra of detrital quartz from the Athabasca Basin is typically dominated by 64 H′3, peaks at g = 2.035 and g = 2.017, #3 and E′1 along with variable amounts of other defects including H′1, H′2 and H′7(III), usually appearing as relatively small peaks. Powder EPR simulations were unable to fit the g = 2.035 and g = 2.017 signals, which are not observed in previously published drusy quartz powder EPR spectra. Attempts to differentiate the signals at g = 2.035 and g = 2.017 as individual defects were inconclusive using low temperature, partial annealing and in single crystal analyses. A single crystal with greater concentrations of these defects (and perhaps lower H′3 concentrations) would be required to determine the source. Given the similarity in the gmax = 2.035 to H′2, this may represent a version of the defect with relatively minor hyperfine splitting. The g = 2.035 and g = 2.017 peak heights are relatively well correlated, and in some samples large peaks at both these g-factors are not accompanied by a large gint amplitude, which may be consistent with the two peaks belonging to a single defect. The lack of correlation with the peaks at g = 2.035 and g = 2.017 with the gint is also seen at low temperature, and similar broadening is observed in both peaks in contrast to H′3. 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Large-scale thermal convection in sedimentary basins revealed by coupled quartz cementation-dissolution distribution pattern and reactive transport modeling – a case study of the Proterozoic Athabasca Basin (Canada). Earth and Planetary Science Letters, 574: 117168. doi:10.1016/j.epsl.2021.117168. Weeks, R.A., and Nelson, C.M. 1960. Trapped electrons in irradiated quartz and silica: II, electron spin resonance. Journal of the American Ceramic Society, 43: 399–404. Weil, J.A. 2003. EPR-NMR. Department of Chemistry, University of Saskatchewan. Yeo, G., Collier, B., Ramaekers, P., Koning, E., Robbins, J., and Jiricka, D. 2001. Stratigraphy of the Athabasca Group in the Southwestern Athabasca Basin, Saskatchewan. Saskatchewan Geological Survey. 73 Appendices Appendix A. Comparison of Quartz and Clay EPR Signal Intensity EPR spectra of equal masses of quartz and clay separates from sample CLU-30-80 (I) -8-6-4-20241.992.002.012.022.032.042.052.06Intensity (a.u.)g-valueClayQuartzP = 2 mW 74 Appendix B. Geochemistry Data ICP-MS Total Digestion (ppm) DDH # Ag As Be Bi Cd Co Cs Cu Dy Er Eu Ga Gd Hf Ho Mo Nb Nd Ni 001 (Canex) 2 0.15 10.7 0.5 <0.1 0.1 0.23 0.4 2.0 0.86 0.53 0.14 5.6 0.9 9.3 0.16 0.24 6.0 16.6 1.3 001 (Ranger) 1 0.09 10.8 0.7 0.1 <0.1 2.25 0.4 2.2 0.92 0.50 0.33 10.6 1.9 5.0 0.16 0.28 4.7 28.4 34.2 002 (Canex) 2 0.04 5.32 0.4 <0.1 <0.1 0.13 0.4 0.8 0.55 0.27 0.21 3.1 1.6 1.0 0.09 0.12 1.3 20.5 1.6 002 (Ranger) 2 0.20 9.02 0.6 0.1 0.1 0.63 0.4 2.8 2.70 1.46 0.48 8.7 2.6 13.1 0.48 0.37 14.5 21.0 19.6 003 (Canex) 2 0.11 8.36 0.5 <0.1 <0.1 0.18 0.5 2.3 0.54 0.32 0.12 5.3 0.7 3.7 0.10 0.55 3.8 13.1 1.0 047 2 0.14 6.79 1.0 <0.1 <0.1 3.26 0.6 1.5 1.67 0.94 0.21 4.6 1.1 1.8 0.31 0.15 2.3 6.4 37.6 2 (Ensign) 1 0.04 4.58 0.4 <0.1 <0.1 0.11 0.4 4.2 0.60 0.32 0.22 5.5 1.0 1.4 0.10 0.07 1.4 10.7 1.5 4-69 1 0.12 9.02 0.6 0.2 0.1 0.10 0.4 1.6 3.22 1.83 0.66 6.5 3.6 13.1 0.58 0.30 5.5 35.8 0.9 5 (Ensign) 1 0.05 8.81 0.6 <0.1 <0.1 0.32 0.3 2.2 1.01 0.50 0.40 8.8 2.2 2.1 0.16 0.14 1.4 23.0 3.6 6 (Ensign) 1 0.08 9.66 0.9 0.7 <0.1 0.39 0.4 2.0 2.31 1.09 0.60 7.8 3.7 8.9 0.37 0.26 3.4 35.5 6.7 78-A 2 0.19 8.07 0.4 <0.1 <0.1 0.22 0.4 1.4 0.97 0.59 0.32 7.2 1.5 5.4 0.18 0.18 14.0 18.6 1.2 AS-001 2 0.10 5.40 0.4 <0.1 <0.1 0.48 0.4 1.6 1.21 0.69 0.40 5.8 1.6 3.8 0.23 0.06 2.6 14.6 2.1 BL-08-01 2 0.06 6.00 0.2 <0.1 <0.1 0.12 0.5 6.9 1.10 0.68 0.21 2.7 1.0 3.0 0.21 0.07 2.1 6.8 1.1 BM-2 1 0.07 8.43 0.7 <0.1 <0.1 3.41 0.4 0.9 0.61 0.30 0.14 9.3 0.7 1.4 0.10 0.12 2.4 5.5 53.2 BR4-4A 1 0.06 4.43 0.2 <0.1 <0.1 0.13 0.6 1.6 0.88 0.47 0.14 3.5 0.7 1.8 0.16 0.08 1.9 4.7 0.9 CAR-114 1 0.05 5.29 0.3 <0.1 <0.1 0.16 0.4 1.5 0.52 0.28 0.25 3.5 1.0 1.5 0.09 0.24 1.9 12.1 1.0 CLC13-066 2 0.48 15.5 3.8 <0.1 0.1 26.5 0.4 2.1 5.44 3.10 0.70 12.1 5.7 15.4 1.00 0.52 21.0 53.1 137.0 CLDD-1 2 0.06 4.34 0.2 0.7 <0.1 0.61 0.4 2.2 0.59 0.30 0.18 5.3 0.8 1.7 0.10 0.11 1.8 6.4 1.0 CLDD-2 2 0.08 5.54 0.3 <0.1 <0.1 1.01 0.4 7.0 0.58 0.28 0.24 4.8 1.2 1.9 0.09 0.08 1.8 14.9 1.2 CLDD-3A 2 0.06 10.5 0.4 0.1 <0.1 0.39 0.2 2.8 0.56 0.26 0.24 10.1 1.0 1.7 0.09 0.12 2.0 9.5 2.5 CLDD-4 1 0.08 5.62 0.3 <0.1 <0.1 0.58 0.3 4.1 0.41 0.19 0.24 5.7 1.2 0.8 0.06 0.10 1.2 13.7 1.4 CLGD003 1 0.06 13.0 1.3 <0.1 <0.1 0.42 0.4 1.4 0.63 0.35 0.21 5.7 0.9 3.1 0.12 0.19 3.1 11.9 19.3 CLU-09-79 2 0.13 7.96 0.5 0.1 <0.1 0.42 0.4 4.0 1.55 0.82 0.50 4.9 3.2 5.7 0.26 0.20 10.4 51.0 1.1 CLU-1805 2 0.09 6.38 0.3 <0.1 <0.1 0.69 0.3 1.3 1.62 0.80 0.41 7.3 1.9 2.8 0.28 0.08 4.0 15.3 1.9 CLU-18-79 1 0.06 4.72 0.2 <0.1 <0.1 0.09 0.3 2.0 0.55 0.32 0.18 2.8 0.7 1.1 0.10 0.14 1.3 7.6 0.9 CLU-2303 1 0.05 4.22 0.3 <0.1 <0.1 0.96 0.3 0.9 1.79 0.95 0.30 4.0 1.4 3.3 0.34 0.18 1.7 10.0 10.6 CLU-30-80 1 0.14 8.03 0.6 0.6 <0.1 1.92 0.4 9.8 1.46 0.74 0.55 8.8 2.2 4.0 0.26 4.16 9.8 22.3 5.2 CR-04 2 0.30 9.39 2.4 0.2 <0.1 22.2 0.4 2.5 3.47 1.55 0.86 7.1 3.7 5.6 0.57 0.32 9.2 24.4 27.0 CSP-06-001 2 0.20 5.50 0.4 0.1 0.1 0.35 0.4 2.9 1.16 0.74 0.43 5.5 1.8 11.4 0.22 0.12 15.4 19.5 6.4 DGS-07 2 0.20 5.36 0.7 <0.1 <0.1 1.12 0.4 3.8 1.06 0.72 0.40 6.3 1.8 10.0 0.22 0.18 13.7 21.4 29.6 DV10-001 2 0.23 7.79 1.8 <0.1 0.1 16.3 0.6 6.1 2.82 1.64 1.38 14.7 4.9 12.2 0.53 0.55 18.1 49.5 65.4 FDL-N474.5E25 2 0.18 10.60 0.6 <0.1 <0.1 0.86 0.5 2.6 1.08 0.66 0.59 7.2 1.7 6.0 0.20 0.20 14.7 17.2 3.5 FDL-S205E700 2 0.09 8.43 0.5 <0.1 <0.1 0.21 0.4 1.8 0.59 0.35 0.34 6.8 1.1 2.1 0.10 0.07 4.8 12.8 1.2 HAR-04 3 0.04 6.38 0.2 <0.1 <0.1 0.10 0.4 2.8 0.49 0.28 0.17 4.0 0.7 1.0 0.09 0.54 1.6 9.1 0.9 HAR-05 2 0.38 11.7 1.0 0.1 0.2 1.26 0.5 8.1 2.38 1.36 0.61 8.1 4.5 29.3 0.41 0.46 25.3 88.4 1.2 HWRG-D11 2 0.05 6.52 0.4 <0.1 <0.1 0.45 0.4 1.5 0.49 0.27 0.13 4.8 0.6 1.8 0.09 0.17 1.8 7.6 3.3 J98-2 1 0.08 8.20 0.3 0.1 <0.1 1.47 0.4 0.8 0.55 0.26 0.12 2.9 0.7 1.0 0.09 0.18 1.9 7.5 8.4 J98-5 2 0.06 4.92 0.3 <0.1 <0.1 0.69 0.4 2.0 0.34 0.19 0.10 4.1 0.4 1.1 0.06 0.04 1.4 4.4 10.7 LA0-5 1 0.16 289 0.3 1.1 <0.1 24.1 0.5 6.4 3.30 1.76 0.37 4.2 2.1 6.5 0.61 0.68 3.0 6.4 85.0 RUMPEL_LAKE 1 0.10 6.47 0.4 <0.1 <0.1 0.23 0.4 2.3 0.60 0.36 0.18 6.7 1.4 4.3 0.10 0.23 7.2 28.4 1.0 SHE3-3 1 0.06 7.26 0.7 <0.1 <0.1 1.00 0.5 1.6 0.67 0.37 0.22 10.1 1.0 2.9 0.12 0.08 3.0 7.8 65.3 TUE0606 2 0.11 4.82 0.3 <0.1 <0.1 0.69 0.4 2.6 1.35 0.78 0.17 3.7 1.0 2.9 0.27 0.23 2.7 5.1 11.8 TUE0606 2 0.06 4.14 0.5 <0.1 <0.1 12.8 0.4 1.6 0.42 0.25 0.15 5.0 0.6 1.9 0.08 0.13 2.3 6.4 47.0 VT-09-01 1 0.11 5.35 1.0 <0.1 <0.1 13.1 0.5 2.8 2.17 1.18 0.54 9.4 2.6 8.7 0.40 0.10 7.1 24.3 48.0 W-1 1 0.10 12.0 0.4 <0.1 <0.1 0.41 0.5 1.2 2.22 1.12 0.61 6.8 3.4 1.2 0.38 0.38 2.8 16.2 3.9 WC-79-1 1 0.06 5.49 0.3 <0.1 <0.1 0.21 0.4 0.7 0.46 0.25 0.16 3.0 0.9 0.9 0.08 0.08 1.5 6.3 0.9 WF-29 2 0.26 7.73 3.7 1.1 <0.1 31.5 0.4 2.0 1.05 0.56 0.25 9.6 1.3 2.0 0.19 1.30 2.2 11.9 73.8 75 ICP-MS Total Digestion (ppm) DDH # 204Pb 206Pb 207Pb 208Pb PbSum Pr Rb Sc Sm Sn Ta Tb Th U W Y Yb Zn 001 (Canex) 2 0.037 1.46 0.683 4.60 6.79 6.2 6.3 1.2 1.4 0.80 0.64 0.13 92.4 5.82 0.9 4.2 0.73 2 001 (Ranger) 1 0.095 2.71 1.60 6.34 10.8 9.0 7.2 2.8 3.4 1.04 0.49 0.17 61.0 2.90 0.5 4.3 0.53 6 002 (Canex) 2 0.026 0.695 0.424 1.08 2.23 5.0 6.7 0.7 3.4 0.36 0.12 0.12 3.02 0.96 1.0 2.3 0.24 1 002 (Ranger) 2 0.043 1.14 0.692 3.83 5.70 7.0 6.6 5.2 3.1 1.59 2.06 0.46 97.8 3.26 0.8 13.8 1.52 4 003 (Canex) 2 0.034 1.50 0.597 3.89 6.02 4.6 7.5 0.8 1.2 0.76 0.43 0.09 68.2 4.12 0.6 2.7 0.38 2 047 2 0.038 1.39 0.633 1.48 3.54 1.7 9.1 0.8 1.2 0.65 0.21 0.26 3.28 6.58 0.9 9.2 1.00 10 2 (Ensign) 1 0.049 0.995 0.778 1.96 3.79 3.1 6.6 0.7 1.4 0.47 0.14 0.12 6.08 2.25 0.2 2.9 0.31 2 4-69 1 0.231 6.11 3.79 11.6 21.7 11.2 6.6 2.5 5.1 0.75 0.45 0.56 38.1 8.85 0.7 16.4 2.05 3 5 1 0.075 1.71 1.20 3.47 6.45 6.8 5.7 0.8 3.3 0.62 0.15 0.23 15.0 2.37 0.4 4.8 0.45 2 6 1 0.073 1.76 1.20 4.99 8.02 10.5 6.9 1.8 5.3 0.75 0.31 0.47 64.8 6.17 0.5 10.5 1.09 2 78-A 2 0.068 1.62 1.11 3.67 6.46 5.8 13.0 1.8 2.4 1.86 1.35 0.18 24.4 4.18 3.7 5.2 0.75 3 AS-001 2 0.060 1.20 0.901 2.48 4.64 4.2 13.0 1.8 2.2 0.68 0.21 0.22 12.3 1.06 0.4 6.5 0.70 2 BL-08-01 2 0.030 0.660 0.509 1.26 2.46 1.8 8.3 1.0 1.3 0.43 0.18 0.18 4.54 0.74 0.3 6.0 0.76 2 BM-2 1 0.029 1.13 0.502 1.82 3.49 1.6 6.6 1.7 0.8 0.45 0.30 0.11 16.6 2.88 1.0 2.8 0.30 2 BR4-4A 1 0.058 1.29 0.937 2.33 4.61 1.3 10.1 1.0 0.8 0.59 0.16 0.14 3.50 0.75 0.4 4.9 0.42 4 CAR-114 1 0.039 0.792 0.628 1.61 3.07 3.4 9.6 0.8 1.7 0.51 0.19 0.10 6.78 0.82 0.3 2.4 0.32 2 CLC13-066 2 0.038 2.77 0.796 3.94 7.54 15.6 8.5 5.8 8.2 4.01 1.91 0.93 105 71.80 1.8 30.0 3.48 13 CLDD-1 2 0.074 1.64 1.22 3.08 6.02 1.8 6.0 0.8 1.0 0.81 0.20 0.11 4.37 1.76 0.3 2.8 0.32 2 CLDD-2 2 0.084 1.97 1.39 3.85 7.30 4.5 6.6 0.8 2.1 1.69 0.17 0.13 8.36 1.18 0.3 2.4 0.28 2 CLDD-3A 2 0.075 1.80 1.23 3.48 6.59 2.9 4.5 1.3 1.3 0.48 0.16 0.12 7.03 1.07 0.3 2.4 0.25 2 CLDD-4 1 0.058 1.35 0.949 2.44 4.79 3.8 5.3 0.7 2.1 3.97 0.10 0.10 2.60 0.80 7.3 1.6 0.18 2 CLGD003 1 0.024 2.70 0.558 1.38 4.67 3.8 6.0 2.4 1.4 0.42 0.50 0.11 19.0 1.53 0.4 3.3 0.42 2 CLU-09-79 2 0.060 1.68 1.01 3.19 5.94 14.2 6.8 1.4 5.8 0.58 0.79 0.29 19.6 2.30 2.7 7.7 0.79 6 CLU-1805 2 0.025 0.567 0.396 1.12 2.11 4.2 16.7 2.1 2.4 0.69 0.32 0.29 9.18 1.02 0.5 9.3 0.73 3 CLU-18-79 1 0.046 1.11 0.769 2.01 3.94 2.1 4.9 0.8 1.1 0.40 0.11 0.09 2.65 0.69 0.2 2.9 0.32 6 CLU-2303 1 0.020 0.592 0.337 0.878 1.83 2.9 6.9 1.6 1.6 0.46 0.15 0.28 3.87 6.60 0.4 10.3 0.86 3 CLU-30-80 1 0.071 1.82 1.16 3.22 6.27 6.0 7.2 3.8 3.2 0.71 0.62 0.28 10.8 2.46 1.5 7.8 0.72 7 CR-04 2 0.053 1.70 0.897 2.40 5.05 6.6 6.8 6.0 4.6 1.42 0.64 0.62 14.2 17.40 1.6 16.3 1.46 8 CSP-06-001 2 0.047 1.16 0.800 2.20 4.20 5.4 8.3 3.3 2.8 1.21 0.82 0.21 13.4 2.05 0.4 6.9 0.87 4 DGS-07 2 0.026 0.790 0.461 2.19 3.47 6.1 6.3 3.7 3.3 2.57 1.15 0.19 56.0 3.43 1.4 6.4 0.95 4 DV10-001 2 0.046 1.59 0.799 2.54 4.98 12.8 15.5 10.8 8.1 1.61 1.29 0.52 27.9 5.55 1.2 15.2 1.73 23 FDL-N474.5E25 2 0.042 1.03 0.691 1.95 3.71 4.8 19.9 2.7 2.6 0.88 1.64 0.21 11.9 2.91 2.0 5.6 0.85 3 FDL-S205E700 2 0.033 0.760 0.547 1.67 3.01 3.8 12.4 1.6 1.8 0.71 0.54 0.12 12.6 0.85 1.2 2.9 0.42 2 HAR-04 3 0.062 1.51 1.00 2.66 5.24 2.6 6.9 0.6 1.3 0.43 0.15 0.09 3.16 0.69 0.3 2.6 0.27 2 HAR-05 2 0.052 1.77 0.905 8.50 11.2 31.5 7.3 3.2 7.4 1.42 2.71 0.41 234 4.22 1.2 12.5 1.48 5 HWRG-D11 2 0.045 0.951 0.712 2.12 3.83 2.5 7.0 0.6 0.9 0.56 0.16 0.08 23.5 1.23 1.7 2.5 0.28 2 J98-2 1 0.025 0.627 0.420 1.50 2.57 2.4 8.0 0.6 1.0 0.53 0.25 0.10 22.0 1.72 0.7 2.5 0.26 1 J98-5 2 0.023 0.542 0.382 1.04 1.99 1.3 9.0 0.9 0.6 0.45 0.14 0.06 5.42 0.68 0.5 1.8 0.22 2 LA0-5 1 0.046 1.09 0.728 1.81 3.67 1.5 15.4 2.9 1.7 1.34 0.35 0.54 5.96 8.02 1.2 20.0 1.68 5 RUMPEL_LAKE 1 0.033 0.910 0.568 2.36 3.87 10.4 7.4 1.4 2.5 1.63 1.13 0.10 55.7 2.18 0.6 2.7 0.42 3 SHE3-3 1 0.040 0.780 0.628 1.78 3.22 2.3 16.2 2.3 1.3 0.63 0.27 0.13 18.3 0.88 0.3 3.8 0.38 3 TUE0606 2 0.028 0.637 0.442 1.06 2.17 1.3 5.5 3.7 0.9 0.47 0.16 0.22 2.29 1.20 1.0 7.8 0.77 3 TUE0606 2 0.030 0.605 0.473 1.27 2.38 1.8 7.2 1.9 1.0 0.56 0.20 0.08 6.66 0.69 0.5 2.2 0.27 6 VT-09-01 1 0.025 0.807 0.440 1.74 3.01 6.8 7.8 3.8 3.7 1.12 0.58 0.38 30.9 9.67 5.7 12.1 1.16 9 W-1 1 0.050 1.74 0.899 2.28 4.97 3.8 9.1 1.9 3.8 1.31 0.24 0.49 4.99 3.10 1.0 11.4 1.12 2 WC-79-1 1 0.031 0.659 0.506 1.37 2.57 1.7 7.5 0.6 1.1 0.43 0.13 0.10 5.47 0.68 0.4 2.5 0.25 4 WF-29 2 0.054 6.44 1.05 2.69 10.2 3.2 6.2 3.6 2.1 0.98 0.19 0.18 4.53 42.30 1.5 5.1 0.56 17 76 ICP Total Digestion (ppm) ICP Whole Rock Assay (wt%) DDH # Ba Ce La Li S Sr V Zr Cr Al2O3 CaO Fe2O3 MgO MnO P2O5 K2O Na2O TiO2 SiO2 Sum 001 (Canex) 2 19 63 44 64 56 83 17.5 474 10 4.82 0.03 3.30 <0.01 <0.01 0.02 0.14 0.07 0.17 91.2 99.75 001 (Ranger) 1 19 93 52 50 125 106 45.8 267 33 5.02 <0.01 3.29 1.13 <0.01 0.05 0.21 0.04 0.26 89.4 99.40 002 (Canex) 2 13 37 14 82 25 55 3.6 44 4 2.89 0.06 1.35 0.07 <0.01 <0.01 0.12 0.27 0.04 95.2 100.00 002 (Ranger) 2 18 66 45 36 35 105 62.3 715 31 4.42 0.01 4.25 0.85 <0.01 0.03 0.17 0.05 0.90 88.1 98.78 003 (Canex) 2 20 44 29 82 60 79 21.9 180 6 4.78 0.03 1.58 <0.01 <0.01 0.03 0.16 0.19 0.07 92.1 98.94 047 2 19 13 7 22 12 26 6.2 96 10 3.52 0.01 0.95 0.63 <0.01 <0.01 0.20 0.11 0.06 93.5 98.98 2 (Ensign) 1 19 31 14 63 26 49 3.8 66 <2 6.41 <0.01 0.08 <0.01 <0.01 0.02 0.12 0.04 0.04 93.0 99.71 4-69 1 81 116 60 23 78 140 13.5 658 8 4.93 0.03 0.12 <0.01 <0.01 0.05 0.12 0.06 0.35 94.4 100.06 5 1 26 75 35 87 86 141 8.8 102 10 8.96 0.05 0.32 0.03 <0.01 0.07 0.11 0.24 0.04 90.3 100.12 6 1 32 120 55 90 65 227 7.6 458 10 6.39 0.03 0.24 0.05 <0.01 0.07 0.19 0.23 0.19 92.2 99.59 78-A 2 19 54 28 19 27 75 17.9 284 18 4.56 0.04 0.19 0.04 <0.01 0.06 0.82 0.20 0.46 93.8 100.17 AS-001 2 26 43 22 9 55 77 10.7 207 5 5.05 <0.01 0.28 0.08 <0.01 0.03 0.90 0.04 0.14 93.3 99.82 BL-08-01 2 13 15 7 4 17 24 3.9 158 <2 3.09 <0.01 0.13 0.07 <0.01 0.02 0.32 0.05 0.08 95.6 99.36 BM-2 1 12 16 10 35 53 33 13.8 70 7 4.47 <0.01 1.11 0.94 <0.01 0.02 0.13 0.06 0.05 93.1 99.88 BR4-4A 1 29 11 5 5 89 18 2.8 87 <2 3.66 <0.01 0.05 0.02 <0.01 0.02 0.21 0.05 0.07 95.6 99.68 CAR-114 1 11 31 14 5 30 51 6.8 68 4 3.57 0.02 0.27 0.04 <0.01 0.04 0.58 0.04 0.06 95.1 99.72 CLC13-066 2 22 149 81 56 263 169 104 771 86 6.54 <0.01 0.80 2.34 <0.01 0.06 0.19 0.03 0.80 89.0 99.76 CLDD-1 2 14 18 9 17 28 30 7.8 83 <2 5.64 <0.01 0.06 <0.01 <0.01 0.02 0.09 0.03 0.05 93.2 99.09 CLDD-2 2 27 47 21 16 47 105 3.7 89 5 4.91 <0.01 0.08 <0.01 <0.01 0.02 0.09 0.05 0.10 94.5 99.75 CLDD-3A 2 19 29 15 107 39 76 8.3 78 6 11.60 0.04 0.09 <0.01 <0.01 0.07 0.08 0.02 0.08 88.4 100.38 CLDD-4 1 25 34 15 47 50 88 4.5 38 <2 5.80 0.04 0.07 0.02 <0.01 0.04 0.11 0.20 0.04 93.5 99.82 CLGD003 1 16 38 24 40 31 68 11.1 160 2 4.74 0.03 3.95 1.07 <0.01 0.01 0.13 0.06 0.15 90.0 100.14 CLU-09-79 2 37 143 61 4 291 184 14.8 306 7 2.69 <0.01 0.13 0.07 <0.01 0.07 0.12 0.05 0.80 95.9 99.83 CLU-1805 2 17 39 22 6 53 80 15.9 141 9 6.29 0.03 1.19 0.14 <0.01 0.09 1.35 0.05 0.22 90.3 99.66 CLU-18-79 1 9 20 9 5 36 35 2.7 53 4 2.70 <0.01 0.16 <0.01 <0.01 0.04 0.09 0.04 0.05 96.9 99.98 CLU-2303 1 10 28 15 10 77 41 7.1 176 2 3.26 0.02 0.15 0.50 <0.01 0.02 0.38 0.05 0.08 95.2 99.66 CLU-30-80 1 69 55 25 8 237 124 57.0 212 32 5.33 <0.01 0.18 0.09 <0.01 0.04 0.16 0.05 0.53 93.5 99.88 CR-04 2 23 58 29 42 69 105 76.6 292 50 6.67 0.04 2.48 2.16 <0.01 0.04 0.17 0.04 0.38 88.2 100.18 CSP-06-001 2 20 48 26 23 57 130 22.4 663 8 3.12 0.02 1.26 0.24 <0.01 0.04 0.35 0.03 1.12 93.6 99.78 DGS-07 2 12 56 32 34 81 91 32.1 533 32 4.77 <0.01 0.75 1.29 <0.01 0.04 0.16 0.05 0.72 92.2 99.98 DV10-001 2 53 84 54 80 103 115 86.5 665 40 12.10 0.03 3.68 3.96 <0.01 0.06 0.72 0.03 1.68 77.7 99.96 FDL-N474.5E25 2 27 50 23 149 40 73 10.8 288 7 7.29 0.02 0.20 0.16 <0.01 0.02 1.28 0.30 0.55 90.3 100.12 FDL-S205E700 2 20 36 18 106 98 67 6.1 99 5 7.50 0.02 0.27 0.06 <0.01 0.04 0.62 0.05 0.13 90.6 99.29 HAR-04 3 11 25 12 10 47 31 2.5 47 3 2.97 <0.01 0.06 <0.01 <0.01 0.03 0.16 0.06 0.05 96.6 99.93 HAR-05 2 47 372 204 3 238 381 18.3 1670 12 2.42 0.02 0.11 <0.01 <0.01 0.16 0.14 0.04 3.03 94.2 100.12 HWRG-D11 2 19 28 15 37 40 43 8.1 85 3 4.75 <0.01 0.10 0.02 <0.01 0.02 0.13 0.21 0.05 94.2 99.48 J98-2 1 16 24 12 14 135 33 3.6 43 <2 2.34 0.04 0.08 0.05 <0.01 0.02 0.32 0.19 0.03 97.1 100.17 J98-5 2 11 14 6 18 38 19 3.3 49 4 3.07 0.07 0.09 0.24 <0.01 <0.01 0.41 0.08 0.03 95.3 99.29 LA0-5 1 52 12 6 15 74 23 24.8 338 11 3.40 0.02 0.14 0.17 <0.01 0.02 0.60 0.07 0.10 95.5 100.02 RUMPEL_LAKE 1 14 107 64 15 44 132 14.5 206 14 5.32 <0.01 0.28 0.04 <0.01 0.06 0.31 0.03 0.46 93.1 99.60 SHE3-3 1 18 22 13 26 45 55 22.8 150 3 6.82 0.01 0.39 0.95 <0.01 0.02 1.04 0.06 0.17 89.9 99.36 TUE0606 2 15 11 5 15 30 34 8.1 151 <2 2.18 <0.01 0.12 0.33 <0.01 0.02 0.11 0.20 0.15 96.6 99.71 TUE0606 2 10 17 8 17 50 29 7.2 91 4 3.37 <0.01 0.12 0.65 <0.01 <0.01 0.20 0.26 0.10 95.0 99.70 VT-09-01 1 13 63 33 35 48 130 18.8 461 16 6.25 0.04 0.26 1.90 <0.01 0.06 0.25 0.22 0.29 90.6 99.87 W-1 1 20 49 15 61 79 225 16.7 63 2 4.60 0.45 1.86 0.08 <0.01 0.38 0.37 0.06 0.06 92.2 100.06 WC-79-1 1 22 15 7 29 41 33 3.6 42 <2 2.82 0.05 0.42 0.04 <0.01 <0.01 0.25 0.08 0.04 95.5 99.20 WF-29 2 15 20 13 54 51 40 83.5 100 19 5.85 0.01 4.01 2.57 <0.01 0.02 0.14 0.09 0.07 87.0 99.76 77 Appendix C. EPR Data DDH # g=2.049 Height (5dB) g=2.049 Height (10dB) g=2.035 (10dB) B/B′ Height (10dB) g=2.017 (5dB) g=2.007 Amplitude (5dB) E′1 Depth (20dB) Basal Formation 001 (Canex) 2 0.20 0.14 0.20 - 0.40 3.03 2.18 - 001 (Ranger) 1 0.27 0.19 0.20 - 0.42 3.08 1.67 - 001 (Ranger) 2 0.28 0.21 0.37 0.06 0.96 3.36 1.71 - 002 (Canex) 1 0.07 0.05 0.02 0.02 0.05 2.00 0.52 - 002 (Ranger) 1 0.09 0.06 0.03 0.03 0.03 1.17 0.36 - 002 (Ranger) 2 0.26 0.20 0.15 0.01 0.41 2.65 1.42 - 003 (Canex) 1 0.39 0.29 0.92 - 2.66 6.09 6.13 - 047 1 0.39 0.28 0.17 0.05 0.34 3.98 1.67 Bird 047 2 0.24 0.16 0.14 - 0.30 2.79 1.32 Bird 2 (Ensign) 2 0.14 0.10 0.02 0.04 0.01 2.10 0.78 - 4-69 2 0.16 0.12 0.09 0.04 0.14 2.13 0.48 Bird 6 (Ensign) 1 0.50 0.25 0.16 - 0.35 3.81 2.12 - 78-A 1 0.10 0.07 - 0.02 0.08 1.32 0.56 Bird AS-001 1 0.21 0.13 0.12 - 0.34 2.15 0.66 Smart AS-001 2 0.13 0.08 0.04 - 0.09 1.20 0.22 Smart BL-08-01 1 0.08 0.07 0.03 0.01 0.09 1.05 0.29 Read BL-08-01 3 0.06 0.04 0.05 - 0.06 0.79 0.31 Read BM-2 1 0.17 0.12 0.13 0.03 0.23 2.01 1.12 Bird BM-2 2 0.24 0.19 0.11 0.08 0.16 2.35 1.90 Bird BR4-4A 1 0.11 0.08 0.03 0.02 0.10 0.98 0.22 Smart BR4-4A 2 0.15 0.10 0.02 0.02 0.04 1.24 0.23 Smart CAR-114 1 0.13 0.09 0.03 0.03 0.06 1.37 0.38 Read CAR-114 2 0.06 0.04 0.02 0.01 0.03 0.74 0.30 Read CLC13-066 1 0.38 0.28 0.22 0.07 0.64 3.36 1.10 Read CLC13-066 2 0.44 0.32 0.44 - 1.29 4.28 2.04 Read 78 DDH # g=2.049 Height (5dB) g=2.049 Height (10dB) g=2.035 (10dB) B/B′ Height (10dB) g=2.017 (5dB) g=2.007 Amplitude (5dB) E′1 Depth (20dB) Basal Formation CLDD-1 1 0.09 0.06 - 0.02 - 1.83 0.45 - CLDD-1 2 0.22 0.15 0.05 0.04 0.02 2.41 1.00 - CLDD-2 2 0.09 0.06 - 0.03 - 1.52 0.64 - CLDD-3A 1 0.12 0.08 0.01 0.03 - 1.65 0.43 - CLDD-4 1 0.06 0.04 - - - 1.17 0.43 - CLDD-4 2 0.07 0.05 - 0.04 - 1.27 0.39 - CLGD003 1 0.29 0.20 0.49 - 1.28 4.04 3.45 Bird CLGD003 2 0.19 0.15 0.09 0.02 0.22 2.35 0.49 Bird CLU-09-79 2 0.21 0.16 0.17 - 0.51 2.22 0.47 Read CLU-1805 1 0.38 0.30 0.09 0.06 0.08 3.99 0.51 - CLU-1805 2 0.33 0.24 0.07 0.06 0.06 3.47 0.71 - CLU-18-79 1 0.13 0.10 0.03 0.04 0.04 1.44 0.37 Bird CLU-18-79 2 0.13 0.09 0.03 0.88 0.05 1.76 0.32 Bird CLU-2303 2 0.07 0.04 0.02 - 0.02 0.76 0.36 Bird CLU-30-80 2 0.12 0.08 0.05 0.00 0.14 1.17 0.36 - CR-04 1 0.06 0.04 0.04 0.03 0.12 0.85 0.33 Read CR-04 2 0.16 0.13 0.19 0.04 0.50 1.97 1.14 Read CSP-06-001 1 0.09 0.07 - 0.05 0.03 1.08 0.72 Read CSP-06-001 2 0.20 0.15 0.08 0.05 0.15 2.27 0.77 Read DGS-07 1 0.13 0.08 0.04 0.05 0.08 1.77 0.51 Fair Point DV10-001 1 0.09 0.06 - 0.16 - 2.95 0.70 Read DV10-001 2 0.18 0.14 0.09 0.13 0.07 5.81 0.98 Read FDL-S205E700 2 0.17 0.14 0.06 0.03 0.12 1.98 0.25 Bird HAR-01 1 0.17 0.12 0.07 0.04 0.14 1.54 0.29 Smart HAR-01 2 0.12 0.07 0.02 0.02 0.10 1.09 0.71 Smart HAR-04 1 0.29 0.20 0.15 0.03 0.43 2.58 0.75 Smart HAR-04 2 0.17 0.13 0.05 0.02 0.14 1.65 0.37 Smart 79 DDH # g=2.049 Height (5dB) g=2.049 Height (10dB) g=2.035 (10dB) B/B′ Height (10dB) g=2.017 (5dB) g=2.007 Amplitude (5dB) E′1 Depth (20dB) Basal Formation HAR-04 3 0.13 0.09 0.05 0.03 0.07 1.35 0.30 Smart HAR-05 1 0.19 0.16 0.44 - 1.30 2.84 1.63 Smart HAR-05 2 0.26 0.20 0.70 - 1.88 3.58 1.94 Smart HWRG-D11 2 0.15 0.12 0.05 0.09 0.07 2.19 1.20 Bird J98-2 1 0.11 0.08 0.06 0.05 0.03 1.92 1.19 Bird J98-2 2 0.10 0.07 0.04 0.08 0.11 1.68 1.00 Bird J98-5 1 0.15 0.11 0.05 0.02 0.09 1.60 0.85 Bird J98-5 2 0.04 0.04 0.01 0.02 0.01 0.81 0.41 Bird LA0-5 1 0.82 0.61 0.19 0.22 - 10.40 2.75 Fair Point P9-81-02 1 0.12 0.09 0.01 0.03 0.41 1.21 0.39 Read P9-81-02 2 0.11 0.09 0.04 0.02 0.06 1.28 0.45 Read RUMPEL_LAKE 1 0.19 0.13 0.09 - 0.02 2.22 1.15 Read RUMPEL_LAKE 2 0.07 0.05 0.04 0.03 0.05 1.29 0.39 Read SHE3-3 1 0.28 0.21 0.17 - 0.32 2.75 1.15 Fair Point SHE3-3 2 0.10 0.07 0.05 - 0.12 0.96 0.87 Fair Point TUE0606 1 0.21 0.15 0.08 0.04 0.14 2.31 0.67 Smart TUE0606 2 0.17 0.12 0.08 0.05 0.14 1.92 0.58 Smart VT-09-01 1 0.21 0.14 0.07 0.04 0.11 2.02 1.30 - VT-09-01 2 0.12 0.09 0.06 0.03 0.06 1.31 0.43 - W-1 1 0.15 0.12 0.05 0.02 0.09 1.73 0.59 Bird W-1 2 0.10 0.07 0.04 - 0.09 1.41 0.42 Bird WC-79-1 1 0.09 0.07 - 0.04 - 1.89 0.30 Read WF-29 1 0.79 0.63 0.34 - 0.55 8.58 3.47 Bird WF-29 2 0.61 0.51 0.27 - 0.40 6.88 2.07 Bird 80 Appendix D. Sampling Data Note: depth values may be shifted due to rounding errors after unit conversion. DDH Company Unconformity Depth (m) # Sample Depth (m) Thin Section Dose Rate (nSv/h) K (%) U (ppm) Th (ppm) 001 Ranger Oil 125.27 1 125.3 X 137 2.8 4.1 20.3 2 123.7 146 2.6 6.4 19.3 001 Canex Arial Exploration Ltd. 257.9 1 257.1 171 2.5 8.4 23.3 2 256.5 158 3.1 6.7 20.0 3 257.7 137 3.1 5.5 15.7 002 Ranger Oil 117.35 1 117.4 133 2.7 5.5 16.8 2 116.1 X 125 2.3 6.0 15.0 002 Canex Arial Exploration Ltd. 356.1 1 354.5 128 3.1 3.0 18.1 2 354.0 126 2.9 4.9 14.8 003 Canex Arial Exploration Ltd. 171.9 1 172.9 250 3.1 4.6 52.5 2 170.5 168 3.0 5.8 25.2 047 Urangesellschaft Canada Ltd. 212.1 1 212 154 2.6 5.8 22.7 2 210.5 137 2.9 5.0 18.0 2 Ensign Oil Ltd. and Fort Reliance Minerals Ltd. 39.3 1 40.6 X 120 2.9 4.5 13.9 2 39.9 133 2.6 6.4 15.3 5 Ensign Oil Ltd. and Fort Reliance Minerals Ltd. 41.8 1 41.9 X 140 2.8 4.5 20.1 2 41.5 131 2.5 4.8 18.5 6 Ensign Oil Ltd. and Fort Reliance Minerals Ltd. 23.8 1 24 150 3.0 5.6 20.2 2 24 139 3.0 5.7 16.8 4-69 Ensign Oil Ltd. and Fort Reliance Minerals Ltd. 46.64 1 46.5 131 2.6 7.0 13.4 2 45.7 122 2.5 7.6 10.0 78-A Numac Oil and Gas Ltd. 212.4 1 212.8 134 2.2 6.6 17.1 2 211.7 147 3.0 4.6 21.4 AS-001 Marline Oil Corporation 487 1 488.4 141 3.3 3.5 20.4 2 486.5 X 130 2.9 5.1 15.5 BL-08-01 Bayswater 965.2 1 965 121 2.8 3.3 16.9 2 964.2 114 2.7 3.3 15.0 3 963.1 X 121 2.5 7.3 10.0 BM-2 SMDC 666.5 1 666.1 144 0.7 7.5 16.0 2 666.5 178 3.5 8.1 21.3 BR4-4A Amok Ltd. 517.4 1 515 128 2.9 5.6 14.2 2 512 81 DDH Company Unconformity Depth (m) # Sample Depth (m) Thin Section Dose Rate (nSv/h) K (%) U (ppm) Th (ppm) CAR-114 Amok Ltd. 1222 1 1222.5 X 142 3.2 5.3 17.6 2 1220.8 113 2.6 2.0 18.0 CLC13-066 Cogema 650.8 1 650.1 X 143 2.0 7.9 18.2 2 649.4 152 1.7 10.9 16.2 CLDD-1 Urangesellschaft Canada Ltd. 52 1 51.3 118 2.5 3.4 17.3 2 49.8 X 120 2.7 4.0 15.6 CLDD-2 Urangesellschaft Canada Ltd. 75.1 1 75.1 133 2.6 3.3 21.4 2 74.4 X 128 2.6 4.0 18.9 CLDD-3A Urangesellschaft Canada Ltd. 72.8 1 72.5 123 2.4 5.5 15.1 2 71.9 129 2.6 4.6 17.4 CLDD-4 Urangesellschaft Canada Ltd. 75.6 1 72.1 115 2.8 4.8 13.8 2 71.6 X 118 2.4 4.5 15.3 CLGD003 D.F. Exploration Uranium Ltd. 911.65 1 911.1 175 2.9 7.0 25.5 2 910.3 141 3.1 5.3 17.5 CLU-09-79 Canadian Occidental Petroleum Ltd. 218.2 1 217.5 X 144 2.9 3.8 22.6 2 216.3 124 2.8 4.6 15.1 CLU-1805 Amok Ltd. 116.3 1 116.1 148 3.3 2.2 25.0 2 115.1 161 3.2 5.5 22.6 CLU-18-79 Canadian Occidental Petroleum Ltd. 111.3 1 111.4 142 2.6 6.4 18.3 2 110.3 151 3.2 6.8 17.3 CLU-2303 Amok Ltd. 211.1 1 211.1 153 3.0 5.0 22.4 2 210.5 163 2.8 7.7 20.7 CLU-30-80 Canadian Occidental Petroleum Ltd. 99.36 1 99 179 3.2 9.7 19.9 2 98 180 3.2 4.5 30.9 CR-04 Uranerz Exploration and Mining Ltd. 1001.1 1 997 136 2.6 6.5 16.2 2 1000.5 X 134 2.5 4.0 20.7 CSP-06-001 Canada Southern Petroleum Ltd. 373.65 1 374.6 169 2.7 6.7 25.3 2 372.2 145 2.9 3.3 23.8 DGS-07 Cogema 747.5 1 746 X 131 2.7 4.6 18.1 2 744.5 133 2.7 5.8 16.0 DV10-001 Fission Energy 1045.25 1 1044.9 143 2.7 2.6 25.8 2 1043.4 X 151 3.1 3.4 24.3 FDL-N474.5E25 Camok Ltd 82.3 1 82.0 149 2.9 6.7 18.0 2 81.4 153 2.7 5.4 22.8 FDL-S205E700 Famok/Camok 319.9 1 320.9 149 3.2 6.3 17.6 2 319.4 148 3.4 3.7 21.5 HAR-01 SMDC 224.3 1 225 127 2.7 6.6 12.9 2 218 82 DDH Company Unconformity Depth (m) # Sample Depth (m) Thin Section Dose Rate (nSv/h) K (%) U (ppm) Th (ppm) HAR-04 SMDC 273.5 1 273.5 138 2.6 6.7 16.2 2 270.5 3 271 125 2.8 5.0 14.8 HAR-05 SMDC 270.7 1 268.7 137 2.6 4.4 20.8 2 269.9 X 167 2.5 3.2 32.7 HWRG-D11 D.F. Exploration Uranium Ltd. 163.57 1 163.4 138 2.7 7.0 14.8 2 162.3 135 2.7 7.0 14.4 J98-2 JNR Resources Ltd. 212.44 1 212.2 148 3.3 5.5 18.3 2 211.5 136 2.9 5.0 17.6 J98-5 JNR Resources Ltd. 260.68 1 260.25 154 2.9 6.4 20.4 2 259.9 144 3.3 4.2 19.6 LA0-5 SMDC 126 1 121.7 136 2.7 3.7 21.2 2 117.7 X 3 118.1 143 3.0 3.6 22.3 P9-81-02 Scurry-Rainbow Oil Ltd. 617.88 1 617.2 120 2.4 3.6 18.1 2 615.8 X 126 2.7 2.9 19.6 RUMPEL_LAKE Gulf Minerals 1457.55 1 1453.7 X 133 2.7 3.8 19.6 2 1453.3 143 3.1 3.3 22.1 SHE3-3 Amok Ltd. 782.9 1 780.3 X 2 780.7 114 2.2 4.8 14.6 TUE0606 Titan Uranium Incorporated 1211.7 1 1121.1 133 3.2 4.1 16.7 2 1209.8 VT-09-01 Titan Uranium Incorporated 1237.55 1 1237.5 157 2.8 6.5 21.4 2 1237 151 2.9 6.2 19.9 W-1 Dejour Mines Ltd. 767.5 1 767 144 3.0 4.4 20.8 2 766 150 2.9 6.0 19.9 WC-79-1 E & B Explorations Ltd. 939.35 1 940 150 3.1 5.0 20.9 2 938 137 2.8 5.6 17.0 WF-29 Cogema 461.7 1 461.2 180 2.9 10.6 20.0 2 461.7 184 2.5 13.2 17.8

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