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Understanding physical property : mineralogy relationships in the context of geologic processes in the… Sterritt, Victoria Athena 2006

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UNDERSTANDING PHYSICAL PROPERTY -MINERALOGY RELATIONSHIPS IN THE CONTEXT OF GEOLOGIC PROCESSES IN THE ULTRAMAFIC ROCK-HOSTED MINERAL DEPOSIT ENVIRONMENT: AIDING INTERPRETATION OF GEOPHYSICAL D A T A by VICTORIA A T H E N A STERRITT B.ScE. , Queen's University, 2004 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF M A S T E R OF SCIENCE in THE F A C U L T Y OF G R A D U A T E STUDIES (Geological Sciences) THE UNIVERSITY OF BRITISH C O L U M B I A October 2006 © Victoria Athena Sterritt, 2006 ABSTRACT Inversion of potential field geophysical data to generate physical property models is becoming increasingly common in the exploration industry. This study aimed to develop relationships between physical properties and mineralogy in ultramafic rock-hosted mineral deposits, based on an analysis of the crater facies-dominated Anuri kimberlite (Canada) and the intrusive magmatic sulfide deposit at Kabanga (Tanzania). Physical property distributions for rock types and minerals that contribute to density and magnetic susceptibility were characterized in both deposits. Magnetic susceptibility is directly related to magnetite abundance, which is an igneous phase and is produced by serpentinization of ultramafic rocks of both deposits. Magnetite in kimberlite also occurs in crustal xenoliths, which dilute the diamond content. Consequently, susceptibility in the Anuri kimberlite is inversely related to diamond grade. In the Kabanga magmatic sulfide deposit, susceptibility is unrelated to ore content, but does indicate the degree of serpentinization. Density is a function of dense minerals concentrated with ore during primary sorting and settling processes in both deposits. As such, density is directly correlated with ore in both volcaniclastic kimberlite breccia of the Anuri kimberlite and ultramafic rocks at Kabanga. However, serpentinization decreases the density of ultramafic rocks significantly, masking any density anomalies associated with sulfide minerals. Modeling demonstrates that a pervasively serpentinized rock with up to 50% sulfide minerals can have a density equal to that of a barren ultramafic rock. A combination of susceptibility and density can be used to identify high-grade rocks in both deposits. In the Anuri kimberlite, rocks with high diamond contents have susceptibilities less -than 10 x 10" SI and densities of 2.42 - 2.51 g/cm . In magmatic sulfide deposits, susceptibility and density can be used to accurately calculate ore mineral abundances. Relationships developed between physical properties and mineralogy for these deposits can not only be applied to other crater facies-dominated kimberlites and both intrusive and extrusive magmatic sulfide deposits, but also to other ultramafic rock-hosted mineral deposits with comparable geologic processes. Consequently, both magnetic and gravity surveys can be interpreted in combination to give a powerful remote tool in predicting grade. i i Table of Contents ABSTRACT .. ii TABLE OF CONTENTS iii LIST OF TABLES ..viii LIST OF FIGURES x ACKNOWLEDGEMENTS xii CHAPTER 1: UNDERSTANDING PRIMARY AND SECONDARY GEOLOGIC PROCESSES IN ULTRAMAFIC ENVIRONMENTS: EFFECTS ON PHYSICAL PROPERTIES AND IMPLICATIONS FOR POTENTIAL FIELD INVERSIONS 1 1.1 Geophysical Inversions 2 1.2 Physical Properties and Their Relationship to Rock Mineralogy 3 1.3 Mineral Deposit Environments 4 1.4 Objectives 6 CHAPTER 2: UNDERSTANDING THE RELATIONSHIP BETWEEN PHYSICAL PROPERTIES AND MINERALOGY WITHIN DIAMONDIFEROUS KIMBERLITE THROUGH GEOLOGIC PROCESSES..... 8 2.1 INTRODUCTION 8 2.1.1 Objectives 10 2.2 GEOPHYSICAL CHARACTERISTICS OF KIMBERLITE 10 2.2.1 Magnetism 11 2.2.1.1 Magnetic Mineralogy 12 2.2.1.2 Volcanic Facies and Magnetism 13 2.2.1.3 Alteration , 15 2.2.1.4 Remanence : 15 i i i 2.2.2 Density 16 2.3 GEOLOGY 17 2.3.1 Regional Geology 17 2.3.2 Geology of the Anuri Kimberlite 17 2.3.2.1 Volcanic Kimberlite Facies 19 2.3.2.2 Formation of the Anuri Kimberlite 21 2.4 INTEGRATING PHYSICAL PROPERTIES, MINERALOGY AND GRADE: PRELIMINARY WORK 22 2.5 ANALYSIS OF MAGNETIC MINERAL PHASES 24 2.5.1 Quantification of the Magnetic Mineral Phases 27 2.5.1.1 Method 27 2.5.1.2 Results 28 2.5.2 Composition of Magnetic Oxide Minerals and Application to Origins 29 2.5.2.1 Ilmenite .29 2.5.2.2 Spinel : 30 2.6 THE RELATIONSHIPS BETWEEN PHYSICAL PROPERTIES AND DIAMOND GRADE 31 2.6.1 Physical Properties and Lithology 32 2.6.2 Physical Properties and Grade 33 2.6.3 Correlation Analysis 37 2.6.3.1 Fine-Scale Variations : 37 2.6.3.2 Coarse-Scale Variations 38 2.6.4 Principal Component Analysis 41 2.7 DISCUSSION 43 2.7.1 Characterization of Dense and Magnetic Minerals 44 2.7.2 Linking Rock Type and Physical Properties through Primary and Secondary Physical Properties 44 2.7.3 Estimation of Diamond Grade from Physical Properties 48 2.8 CONCLUSIONS 48 iv CHAPTER 3: QUANTIFYING THE EFFECTS OF PRIMARY AND SECONDARY GEOLOGIC PROCESSES ON PHYSICAL PROPERTIES IN THE MAGMATIC SULFIDE ENVIRONMENT 50 3.1 INTRODUCTION 50 3.1.1 Objectives 54 3.2 GEOPHYSICAL CHARACTERISTICS OF MAGMATIC SULFIDE DEPOSITS 54 3.2.1 Magnetism 56 3.2.2 Gravity 56 3.3 GEOLOGY OF THE KABANGA DEPOSITS 56 3.3.1 Regional Geology ; 56 3.3.2 Local Geology 59 3.4 PHYSICAL PROPERTIES OF THE KABANGA ULTRAMAFIC COMPLEX LITHOLOGIES 64 3.4.1 Magnetic Susceptibility . 67 3.4.2 Density 69 3.4.3 Quantitative Relationships Between Serpentinization and Physical Properties 72 3.4.3.1 Remobilization of Metals and Sulfide Minerals during Serpentinization 74 3.4.4 Statistical Correlation Analysis of Geological and Geophysical Properties 77 3.5 MINERAL PREDICTION FILTER 79 3.5.1. Modeling of Serpentinization and Mineralization 82 3.6 DISCUSSION 83 3.6.1 Density 84 3.6.2 Magnetic Susceptibility 84 3.7 CONCLUSIONS AND IMPLICATIONS FOR OTHER MAGMATIC SULFIDE DEPOSITS 85 CHAPTER 4: IMPLICATIONS OF PHYSICAL PROPERTY - MINERALOGY RELATIONSHIPS FOR INTERPRETATION OF INVERSIONS 90 4.1 Physical Property - Mineralogy Relationships for Kimberlite and Magmatic Sulfide Deposits 90 4.2 Implications for Geophysical Inversions 98 4.2.1 Kimberlite: Anuri Case Study... 98 4.2.3 Magmatic Sulfide Deposits: Kabanga Case Study 100 CHAPTER 5: CONCLUSIONS 104 5.1 Limitations of Study 104 5.2 Conclusions 104 5.3 Recommendations for Future Work 109 REFERENCES I l l APPENDIX A: MAGNETIC SUSCEPTIBILITY AND DIAMOND GRADE DATA FOR A L L DRILLHOLES 117 APPENDIX B: COMPOSITIONAL ANALYSIS OF ILMENITE GRAINS WITHIN THE ANURI KIMBERLITE 119 APPENDIX C: COMPOSITIONAL ANALYSIS OF MAGNETITE GRAINS FROM THE ANURI KIMBERLITE 126 APPENDIX D: COMPOSITIONAL ANALYSIS OF CHROMITE GRAINS WITHIN THE ANURI KIMBERLITE 129 APPENDIX E: METHODOLOGY FOR MEASUREMENT OF PHYSICAL PROPERTIES 131 APPENDIX F: PHYSICAL PROPERTY AND GRADE DATA FOR THE LT508-1 DRILLHOLE 132 APPENDIX G: PHYSICAL PROPERTY AND GRADE DATA FOR THE HYPABYSSAL KIMBERLITE OF LT508-4 DRILLHOLE 133 VI APPENDIX H: PHYSICAL PROPERTY DISTRIBUTIONS OF ANURI KIMBERLITE LITHOLOGIES 134 APPENDIX I: GEOLOGIC AND GEOPHYSICAL PROPERTIES USED FOR COVARIANCE AND PRINCIPLE COMPONENT ANALYSIS 136 APPENDIX J: DESCRIPTIONS OF THE MAIN ROCK TYPES AT KABANGA 142 Quartzite : 142 Schist 142 Metapelite 142 Diabase.. 143 Gabbro 144 Pyroxenite 145 Peridotite 147 Semi-Massive Sulfide 150 Massive Sulfide 153 APPENDIX K: PHYSICAL PROPERTY HISTOGRAMS . 155 APPENDIX L: PHYSICAL PROPERTY AND GEOCHEMICAL DATA FOR THE KABANGA SAMPLES 157 APPENDIX M : DATA FOR QUANTITATIVE ESTIMATION OF SERPENTINIZATION AND PHYSICAL PROPERTIES.... 165 APPENDIX N: CORRELATION ANALYSIS RESULTS FOR KABANGA SAMPLES. 167 APPENDIX O: RESULTS OF MINERAL PREDICTION FILTER CALCULATIONS FOR KABANGA SAMPLES 168 vii List of Tables Table 1.1: Comparison of average density and susceptibility 1 of major rock types and oxide, sulfide, and silicate minerals 4 Table 2.1: Comparison of the facies, magnetic susceptibility and density of kimberlite pipes throughout the world 2 .„ 12 Table 2.2: Density characteristics of the different kimberlite facies, as measured from Siberian kimberlite pipes (Arnott and Kostlin, 2003) 17 Table 2.3: Description of rock types identified in the Anuri kimberlite (Masun et al., 2004)3 19 Table 2.4: Hydrous/alteration minerals identified based on PIMA spectra in the Anuri LT508-01 drillhole as a function of depth, magnetic susceptibility and kimberlite facies 4 22 Table 2.5: Summary of the occurrences of magnetic mineral phases5 25 Table 2.6: Magnetic susceptibility, volcanic facies, stones/100 kg and macrocryst:microcryst ratios (mac:mic) for the intervals studied from the LT508-1 drill core 6 ..27 Table 2.7: Summary of the number of grains analyzed from each lithology that were chromite, ilmenite and magnetite7 28 Table 2.8: Summary of physical property and grade statistics 8 (average and standard deviation (st dev)) for lithologies of the Anuri kimberlite 32 Table 2.9: Matrix of correlation coefficients between the various grade, geologic features and physical properties measured on a fine-scale 9 ; 39 Table 2.10: Correlation coefficients between the various grade, geologic and physical properties measured on a coarse-scale 1 0 ; ; < .40 Table 2.11: Tables indicating the eigenvalues, variability explained by each component and the cumulative variability of the data explained by the three components determined to be significant using the scree test, for fine-scale data (left) and coarse-scale data (right). ......42 Table 2.12: Factor loadings for the significant components (FI, F2, F3) created by the Principal Component Analysis of both the fine (left) and coarse (right) scale data...... ...43 Table 3.1: Characteristics of select economic stratiform Ni-Cu-(PGE) sulfides (from Naldrett, 2004) 51 Table 3.2: Comparison of magnetic susceptibility and density of minerals common in mafic-ultramafic intrusions and associated sulfide deposits 1 1 55 Table 3.3: Summary of metamorphic and deformation events within the metasedimentary country rocks and mafic-ultramafic intrusions, in approximate chronological order (Holman, 1999) .....59 Table 3.4: Summary of the main rock types at Kabanga, including country rocks (metasedimentary), mafic-ultramafic host rocks and mineralized host rocks (semi-massive to massive sulfide)12 .......60 Table 3.5: Average physical properties 1 3 , with standard deviations (st dev), of the rock types at Kabanga....64 Table 3.6: Comparison of magnetic susceptibility and density distributions (Dist.)14 for the samples collected for this thesis ("samples") and drillhole database ("database") assembled by Kabanga Nickel Company 67 Table 3.7: Table displaying the loadings 1 5 for the factors (F#) calculated by the principal component analysis. ....79 Table 3.8: Results from modeling of densities for mineralized and serpentinized samples, showing the calculated amount of pyrrhotite that can occur in a serpentinized rock to produce the same density as a barren diabase, gabbro or peridotite/pyroxenite host rock. .83 Table 4.1: Comparison of the geological and geophysical properties of kimberlite and magmatic sulfide deposits, using the Anuri kimberlite and the Kabanga massive sulfide deposit as respective examples ....91 vm Table 4.2: Comparison of geological and geophysical properties of different mafic-ultramafic rock-hosted mineral deposits where the ore mineral is syngenetic 95 Table 4.3: Summary of magnetic susceptibility statistics for the country rock and kimberlite lithologies of the Anuri kimberlite 99 Table A . l : Magnetic susceptibility and diamond content measurements for LT508-05 drillhole 117 Table A.2: Magnetic susceptibility and diamond content measurements for LT508-03 drillhole 117 Table A.3: Magnetic susceptibility and diamond content measurements for LT508-01 drillhole 118 Table A.4: Magnetic susceptibility and diamond content measurements for LT508-08 drillhole 118 Table B. l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for ilmenite grains separated from samples of the Anuri kimberlite 1 6 119 Table C . l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for magnetite grains separated from the Anuri kimberlite 126 Table D. l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for chromite grains separated from the Anuri kimberlite 129 Table F . l : Summary of physical properties and diamond content indicators for the LT508-1 drill core studied in this thesis 132 Table G. l : Summary of physical properties and diamond content indicators for the LT508-4 drillcore that sampled the hypabyssal kimberlite of the eastern lobe. Data provided by Kennecott Exploration 133 Table J . l : Table detailing the modal percent estimates of silicate and opaque mineralogy of the diabase samples from the North and Main bodies at Kabanga, as estimated from optical petrography 144 Table J.2: Summary of the modal percent estimates of mineralogy for the gabbro samples from the Kabanga North and Main ore bodies, t is for trace amounts (less than 1 vol.%) 145 Table J.3: Summary of the main textures of the pyroxenite samples from the Kabanga North (N) and Main (M) bodies 146 Table J.4: Summary of the modal mineralogy of the pyroxenite samples from the Kabanga North (N) and Main (M) bodies 147 Table J.5: Summary of the main textures of the peridotite samples from the Kabanga North and Main bodies 149 Table J.6: Modal mineralogy estimates for peridotite samples from Kabanga Main and North 150 Table J.7: Summary of some main textural characteristics of the semi massive sulfide samples from the Kabanga North and Main samples 152 Table J.8: Table summarizing model mineralogy estimates for semi-massive sulfide samples from Kabanga Main and North ore bodies 153 Table J.9: Summary of the modal mineralogy (as a percent, t for trace amounts) for the massive sulfide samples gathered from both the Kabanga Main and North bodies 154 Table L . l : Physical Properties and Major Element Geochemistry for Kabanga Samples 157 Table L.2: Metal contents of the Kabanga samples, measured as ppm unless otherwise specified 160 Table L.3: Additional geochemical analyses for the Kabanga rock samples, focusing on parameters that may indicate alteration 163 Table M . l : Data used for testing quantitative relationships between physical properties and degree of serpentinization using the Kabanga samples 165 Table N.l: Correlations between various geological and geophysical properties for Kabanga 167 Table O. l : Chart comparing the ore mineral contents estimated modally during petrographical analysis for the Kabanga samples to the mineral abundances calculated for the minimized and maximized sulfide versions of the Mineral Prediction Filter. 168 List of Figures Figure 1.1: Exploration workflow, illustrating how physical property models produced from geophysical data, gravity and magnetics, can be quantitatively linked to geologic features including mineralogy 2 Figure 2.1: Location of the Anuri kimberlite 9 Figure 2.2: Range of densities and susceptibilities characteristic of the main minerals of altered kimberlite..l 1 Figure 2.3: Chart illustrating the two trends identified in kimberlite spinels, as defined by Mitchell (1995)... 13 Figure 2.4: Schematic diagram of facies within an idealized kimberlite 14 Figure 2.5: Schematic cross section of the Anuri kimberlite 18 Figure 2.6: Results from geophysical surveys conducted over the Anuri area 20 Figure 2.7: Sequential steps in the formation model of the Anuri kimberlite............. 21 Figure 2.8: Plot of macrocryst:microcryst diamond ratios versus magnetic susceptibility 23 Figure 2.9: Macrocryst (>1 mm): microcryst (<1 mm) ratio versus stones/100 kg for the LT508-1 drillhole through the Anuri kimberlite 24 Figure 2.10: Photomicrograph of kimberlite showing textural characteristics of magnetic minerals in the Anuri pipe 26 Figure 2.11: Schematic flow diagram illustrating sample preparation for mineral phase analysis 27 Figure 2.12: Plot of the T i 0 2 wt% vs. MgO wt% of ilmenite 30 Figure 2.13: Ternary diagram illustrating the composition of spinels from Anuri, with respect to genetic fields defined from study of other kimberlite spinels (Barnes and Roeder, 2001) 31 Figure 2.14: Plot of magnetic susceptibility and density characteristics of kimberlite lithologies 33 Figure 2.15: Plot illustrating diamond grade characteristics of kimberlite lithologies 34 Figure 2.16: Schematic plot illustrating qualitative relationships between the grade indicators (stones/100 kg and macrocryst: microcryst) and physical properties (magnetic susceptibility and density) with depth 35 Figure 2.17: Physical property characteristics of samples with diamond content.. 36 Figure 2.18: Macrocryst: microcryst ratio plotted in susceptibility-density 36 Figure 2.19: "Scree" plot for the Principal Component Analysis 42 Figure 2.20: Schematic diagram showing the effects of serpentinization (black arrows) on physical properties of kimberlite 46 Figure 2.21: Schematic diagrams of a simplified kimberlite pipe 47 Figure 3.1: Simplified cross-sections of an extrusive (A) and intrusive (B) magmatic sulfide deposit 52 Figure 3.2: Location map of the Kabanga deposit in northwestern Tanzania .....53 Figure 3.3: Comparison of density and susceptibility of main mineral constituents of magmatic sulfide deposits 55 Figure 3.4: Schematic geological cross-section of the Kabanga North and Main bodies 58 Figure 3.5: A) Reduced to the Pole Aeromagnetic Map of the East African Nickel Belt. B) Enlarged magnetic map of the Kabanga area based on ground magnetic surveys 62 Figure 3.6: Gravity data covering the Kabanga area, adjusted using a complete Bouguer anomaly 63 Figure 3.7: Histograms of magnetic susceptibility and density distributions of each rock type 66 Figure 3.8: A) Relationship between modal % magnetite and magnetic susceptibility for the Kabanga rock types. B) Relationship between magnetic susceptibility and the amount of monoclinic pyrrhotite for the massive sulfide samples 68 Figure 3.9 Plot illustrating relationships between ferric, ferrous and total iron and magnetic susceptibility ..69 Figure 3.10: Chart illustrating the relationship between density and pyrrhotite 70 Figure 3.11: A) Plot illustrating the relationship between density and H 2 0 . B) Relationship between density and magnetite 71 Figure 3.12: Charts showing misfits between measured and calculated density (A) and magnetic susceptibility (B) 73 Figure 3.13: Microphotograph of pyrrhotite (Po) being replaced by magnetite (Mgt) and intergrown with serpentine .74 Figure 3.14: A) Relationship between base metals (nickel and copper) and magnetite. B) Relationship between precious metals (platinum and palladium) and magnetite 75 Figure 3.15: Plot of magnetic susceptibility and the pyrrhotite/magnetite ratio 76 Figure 3.16: Eigenvalues for the factors calculated by the Factor Analysis 78 Figure 3.17: Misfit between mineral abundances predicted by the Mineral Prediction Filter (Williams and Dipple, 2005) and mineral abundances estimated optically during petrographic analysis. A) Results from the Minimized Sulfides Program. B) Results from the Maximized Sulfides Program 81 Figure 3.18: Comparison of the amount of each pyrrhotite polytype estimated by the Mineral Prediction Filter (Williams and Dipple, 2005) (y-axis) and measured using methods described by Graham (1969) and Arnold (1966) from x-ray diffraction patterns (x-axis) for the massive sulfide samples 82 Figure 3.19: Schematic diagram illustrating relative physical properties of fresh mafic and ultramafic rocks and how physical properties are altered by mineralization (black arrows) and serpentinization (dark grey arrows) : 87 Figure 3.20: Schematic diagrams illustrating relative density (A) and magnetic susceptibility (B) of ore, host rocks and country rocks ....87 Figure 4.1: Density model using a cutoff of -0.15 g/cc density contrast 100 Figure 4.2: Isosurfaces of the high and low density bodies at Kabanga of the density contrast model 101 Figure 4.3: Isosurfaces of high and low regions of density contrast model in the vicinity of the Kabanga Main (A) and Kabanga North (B) ore 103 Figure H. l : Histograms of physical property characteristics for the autolithic volcaniclastic kimberlite breccia (top row), heterolithic volcaniclastic kimberlite breccia (middle row) and lithic breccia (bottom row). 135 Acknowledgements I would like to thank my supervisor Richard Tosdal for his support and suggestions. I would also like to acknowledge the rest of the Mineral Deposit Research Unit for their assistance. Specifically, I would like to thank my committee members, James Scoates and Kelly Russell, both of whom helped me with different aspects of my research. Kelly also provided much of the initial inspiration for my work with the Anuri kimberlite. Nigel Phillips was instrumental in helping me understand physical properties and inversions, especially the MDRU-GIF inversion code. Thanks to Ken Hickey for providing feedback on many presentations. Special thanks to Claire Chamberlain for providing me with direction, endlessly editing my work and making it more punchy, and showing me around Tanzania. This thesis would not have been completed, or comprehensible, without her help. Thanks to Mati Raudsepp for teaching me how to use the S E M and Microprobe. Sasha Wilson was kind enough to teach me to carbon coat and how to use the X R D . Thanks to Arne Toma for helping me with all my computer/printer/presentation issues, and always being calm every time I jammed the printer. I must thank many of my peers for all of their support. Particularly, Nick Williams deserves a lot of credit for answering all of my absurd questions, always being up for a discussion of the project and for developing the Mineral Prediction Filter. Emma Gofton and Erik Scheel provided a lot of valuable feedback on my work with kimberlites and magmatic sulfide deposits, respectively. I also need to thank Dianne Mitchinson and Kirsten Rasmussen for tolerating me as an officemate and providing much needed distractions. I would like to thank Tashia Dzikowski for enduring my complaints and rejoicing in my successes. I am grateful to my parents, for supporting me always. Lastly, I would like to thank Craig Crooks for supporting me through this thesis. I would not have maintained my sanity without him. This project was funded by the Mineral Deposit Research Unit - Geophysical Inversion Facility joint project, which is sponsored by a consortium of ten companies with funds matched by NSERC. The ten mining companies are AngloGold Ashanti Ltd, Barrick, Geoinformatics Exploration, Inco, Kennecott Exploration, Noranda/ Falconbridge, Placer Dome Inc., Teck Cominco Ltd., and W M C Resources Ltd. xiii Chapter 1: Understanding primary and secondary geologic processes in ultramafic environments: effects on physical properties and implications for potential field inversions Major economic mineral discoveries in the future will likely be under cover rocks or at depth, as a large majority of profitable mineral deposits exposed at surface have already been found in well-explored regions. To assist in the discovery of these future economic deposits, the exploration process needs to move its focus to further developing geophysical techniques that remotely sample rocks in the subsurface. Geophysical methods record physical properties of rocks within the Earth's crust, allowing for interpretation of geologic features at depth (Clark, 1997; Phillips, 2002; Williams et al., 2004). Furthermore, some geophysical surveys, such as potential field geophysical surveys, are a cost-effective reconnaissance topi, which permit large areas to be covered as a rapid method for identifying anomalous zones in the subsurface (Corbett, 1992; West, 1992; Clark, 1997; Williams et al., 2004). Geophysics, where the data is appropriate, can also identify small-scale features, thereby highlighting particular areas of economic interest in large regions (Phillips, 2002). Interpretations of geophysical and physical property data have largely been qualitative (Gingerich, 2003). Three-dimensional physical property modeling via recently developed inversion codes, however, provides a quantitative method of viewing geophysical data (Oldenburg et al., 1998). These physical property models provide the link between geology and geophysical data, allowing for straightforward interpretation of physical property data in terms of geological features. Nonetheless, to date, there has been limited effort to fully integrate physical properties, mineralogy, and geologic processes into general or specific deposit models (Gingerich, 2003; Clark, 1997), largely because of a lack of understanding of interrelations between geological processes, mineralogy and physical properties. Bridging this knowledge gap will improve the accuracy of quantitative interpretations of geophysical inversion models with respect to mineralogy. This study contributes to building this link by developing qualitative and quantitative relationships between mineralogy and physical properties, through an improved understanding of the effects of primary and secondary geological processes on these inter-related geologic characteristics. Ultramafic rock-hosted mineral deposits, notably a kimberlite and layered mafic-ultramafic magmatic sulfide deposit, are the focus of this thesis. These deposits share similar gross-scale rock compositions, although they represent very different primary geologic environments and can be of significant economic value. 1 1.1 Geophysical Inversions Geophysical surveys provide a wealth of information about geological features, including rock type and mineralogy. However, efforts to quantitatively interpret geophysical surveys with respect to mineralogy have been limited due to technical difficulties in manipulating geophysical data into a geologically meaningful form (Gingerich, 2003). Advances in computing power have allowed for development of algorithms that can invert geophysical data to produce one-, two- or three-dimensional physical properties models that link geophysical data to geologic properties (Figure 1.1) (Oldenburg et al., 1998). Consequently, physical property models can now be interrogated for information regarding mineralization (Figure 1.1), associated structures or lithological units (Oldenburg et al., 1998), given a good understanding of the effects of geologic processes on physical properties. As such, these models are valuable aids to mineral exploration, as either mapping techniques or to facilitate testing of conceptual geologic models. Gravity Data Data Grav3D Inversion Mag3D Inversion Inversion Density Model Mineral Prediction Filter Inversion Susceptibility Model Figure 1.1: Exploration workflow, illustrating how physical property models produced from geophysical data, gravity and magnetics, can be quantitatively linked to geologic features including mineralogy. The quantitative link between physical properties and mineralogy developed for magmatic sulfide deposits is the Mineral Prediction Filter (Williams and Dipple, 2005), which assumes that physical properties of samples represent linear combinations of physical properties of the constituents. Modified after Williams (2006). Inversions conducted using The University of British Columbia - Geophysical Inversion Facility (UBC-GIF) codes employ data measured in geophysical surveys (e.g. magnetic, gravity, resistivity, induced polarization data) to solve for the three-dimensional spatial distribution of the according physical property (e.g. magnetic susceptibility, density, electrical conductivity, or chargeability, respectively). To do this, the earth is discretized into constant-property cuboidal cells (Oldenburg et al., 1998; Phillips, 2002). A solution is acquired by minimizing a model objective function, which contains one term that forces the constructed model to converge to a reference model, and terms that penalize roughness in each spatial direction. Solutions are required to reproduce the original data within a given error (Oldenburg et al., 1998; Phillips, 2002). Physical property models generated by inversion are inherently non-unique; an infinite number of solutions are equally valid (Oldenburg et al., 1998; Phillips, 2002). Solutions can be constrained to resemble geological models through input parameters such as smoothness, physical property ranges, reference models, and errors. A good understanding of the relationship between physical properties and mineralogy not only assists in meaningful interpretation of inversion models, but can be extremely useful in setting initial inversion parameters which will guide the inversion towards a more realistic geologic model. 1.2 Physical Properties and Their Relationship to Rock Mineralogy Of the many geophysical methods available, magnetic and gravity surveys are the most common geophysical tools used in the exploration industry (Clark, 1997). Gravity data are the simplest to interpret, because its corresponding physical property, density, is derived from a linear combination of densities of each mineral phase. Interpreting the results of magnetic surveys is more complex, as magnetic susceptibility is not only a function of the susceptibility of each mineral component, but also the grain size of the components. Additional factors, including grain size, may play a role in influencing density and susceptibility, but abundance and distribution of key minerals, such as sulfide and oxide minerals, is the primary control. The physical property analysis for this study focuses on density and magnetic susceptibility. In understanding the relationships between these physical properties, mineralogy and geology, there is potential to gain insight into the effects of primary and secondary processes occurring within a specific geological environment on physical properties. Physical properties of silicate minerals typically vary over a small range; densities of common silicate minerals can vary from low (< 2.7 g/cm ) for quartzo-feldspathic and common alteration minerals (serpentine, clay) to moderate (> 3 g/cm3) for ferromagnesian minerals (Table 1.1). The magnetic susceptibility of most silicate minerals tends to be insignificant (< 0.2 x 10"3 SI generally). Conversely, sulfide and oxide minerals have drastically different physical properties relative to silicate minerals. Sulfide and oxide phases tend to be dense (> 3 g/cm3) and have higher susceptibilities (roughly 0.4 - 60003 SI). Common phases with high magnetic susceptibilities include magnetite, pyrrhotite, ilmenite, chromite and spinel (Telford et al., 1990; Hunt et al., 1995, Gunn and Dentith, 1997). Magnetite is a primary component within mafic-ultramafic rocks and can also be a product of serpentinization (O'Hanley, 1996). Monoclinic pyrrhotite occurs in trace amounts in many common rocks but is abundant in massive sulfide. It is one of ten polytypes of pyrrhotite (Chung and Lee, 2003) and is the second most abundant pyrrhotite polytype (Karpenov et al., 1979). Ilmenite and spinel are common primary minerals 3 within mafic-ultramafic rocks. Although these phases may not be the ore minerals in question in many deposits, their presence in appreciable quantities may signify geological processes that have concentrated ore minerals. The distinct physical property ranges of these components make them easy to detect using geophysical methods, in contrast with silicate phases. Table 1.1: Comparison of average density and susceptibility of major rock types and oxide, sulfide, and silicate minerals. (Telford et al., 1990). Average susceptibilities appear in brackets. Rock/Mineral Density (g/cm3) Magnetic Susceptibility (10'3 SI) Clay 1.63-2.6 0.2 Sandstone 1.61 -2.76 0-20 (0.4) Limestone 1.93-2.90 0-3 (0.3) Granite 2.50-2.81 0-50 (2.5) Diabase 2.50 - 3.20 1 -160(55) Gabbro 2.70 - 3.50 1 - 90 (70) Peridotite 2.78 - 3.37 90-200(150) Chromite 4.3-4.6 3-110 (7) Ilmenite 4.3-5.0 1200-3500(1800) Magnetite 4.9-5.2 1200-19200 (6000) Hematite 4.9-5.3 0.5-35(6.5) Chalcopyrite 4.1 -4.3 0.4 Pyrrhotite 4.5-4.8 1-6000(1500) Pyrite 4.9-5.2 0.05-5(1.5) Quartz 2.5-2.7 -0.01 Orthoclase 2.5-2.6 Calcite 2.6-2.7 -0.001--0.01 Biotite 2.7-3.2 Serpentine 2.4-3.10 3-17 1.3 Mineral Deposit Environments Some mineral deposit types are large and readily characterized by their consistent and distinct physical properties. Examples include magmatic sulfide deposits (e.g. Noril'sk, Russia; Kambalda; Australia; Naldrett, 2004), iron oxide-copper-gold deposits (e.g. Olympic Dam, Australia; Porter, 2000), and iron formations (e.g. Paraburdoo, Australia; Beukes, 2003) (Gunn and Dentith, 1997). Other deposit types can have small footprints and be more variable in their physical properties, thus making them difficult to detect. Examples include kimberlite pipes (e.g. Ekati, Canada; Kimberly, South Africa), carbonatites (e.g. Palabora, South Africa), and podiform chromite (e.g. Troodos ophiolite complex, Cyprus) (Gunn and Dentith, 1997). Two ultramafic rock-hosted deposits were chosen for study and represent both large and small deposit types with characteristic and variable physical properties, respectively. Characterizing the physical properties of ultramafic rocks and associated mineralization relative to country rocks is relatively straightforward as physical properties of ultramafic rocks are distinct from those of typical quartzo-feldspathic country rocks, due to their mineralogy. Assessing physical properties of deposits hosted by quartzo-feldspathic rocks, such as porphyry-associated deposits, is inherently more difficult as the ore-associated units have properties similar to those of the country lithologies. Furthermore, ore is syngenetic in ultramafic-hosted deposits, so the relationship between ore mineralogy and physical properties related to particular geologic processes is simpler to understand and quantify. The deposit types chosen for this study, the Anuri kimberlite, Canada, and the magmatic sulfide deposit at Kabanga, Tanzania, are significant sources of diamonds and nickel-copper-platinum group elements (PGE), respectively (Dowsett, 1970). Kimberlite pipes generally have small footprints of less than 2 km in diameter (Mitchell, 1986; Keating, 1996). Their geophysical expressions and physical property characteristics can differ drastically from one pipe to another, depending on host rock and kimberlite facies. An improved understanding of the range of physical properties associated with kimberlite could make interpretations of geophysical anomalies related to these pipes more geologically meaningful. In contrast, magmatic sulfide deposits are associated with large ultramafic flows or intrusions of relatively consistent mineral composition and physical properties. These rocks are commonly emplaced into more felsic country rocks characterized by markedly different densities and magnetic susceptibilities. Because of the physical property contrasts, magmatic sulfide deposits lend themselves to a study of the quantitative connection between physical properties and mineralogy. Despite differences in ore minerals and emplacement mechanisms, both ultramafic rock-hosted deposit types share several common features. Physical property anomalies in both kimberlite and magmatic sulfide deposits are not produced by the ore minerals, which are diamond concentrations within kimberlite and Fe-Ni-Cu sulfide minerals in massive sulfide. Rather, physical property anomalies are caused by minerals spatially associated with the ore minerals through primary geologic processes, including pyroclastic eruption and crater-fill, and gravitational settling of a segregated sulfide melt, respectively. Such minerals include dense magnetic oxide minerals in kimberlite and magnetic pyrrhotite in massive sulfide. As kimberlite and magmatic sulfide deposits are both hosted by ultramafic rocks, they are susceptible to similar secondary processes, such as serpentinization that can significantly modify the primary physical properties of the rock. 1.4 Objectives Inversion codes now make production of quantitative three-dimensional physical property models from geophysical data possible. However, the ability of the exploration industry to 5 interpret physical properties in a geologically meaningful manner is still limited. A better understanding of the influence of geology, specifically mineralogy, on physical properties is required. This research project aims to develop an understanding of relationships between physical properties and mineralogy related to the primary and secondary geological processes in ultramafic rock-hosted mineral deposits. Specifically, the objectives of this study are to: 1) Characterize dense and magnetic phases present in rock types associated with two ultramafic rock-hosted mineral deposit environments, a kimberlite and a magmatic sulfide deposit; 2) Understand how dense and magnetic minerals in both kimberlite pipes and magmatic sulfide deposits relate to the ore minerals of both deposits at the time of formation and throughout the history of the deposits; 3) Characterize physical property distributions of significant rock types for each deposit and explain variations and anomalous physical properties through differences in geologic processes; 4) Develop a method of identifying high-grade samples based on physical properties, by establishing how geological processes concentrate ore minerals with dense and magnetic minerals; 5) Apply physical property - mineralogy relationships to the improvement of inversions and interpretation of physical property models; 6) Synthesize learnings from both deposits studied in this thesis and extrapolate to other ultramafic-hosted mineral deposits. The first two objectives are addressed by petrographically identifying dense and magnetic minerals and using textures to determine modes of occurrence of each phase. Objectives three and four are achieved using graphical and statistical techniques to characterize distributions and assess the strength of correlations between geologic variables. These issues may allow for development of quantitative relationships between physical properties and mineralogy for fresh and altered ultramafic rocks. Subsequently, physical property data produced by inversion of geophysical data can be interpreted with respect to rock type and ore content for various degrees of alteration in different ultramafic-hosted mineral deposits. The outcomes of this study have implications for the interpretation of physical properties with respect to geological features: 6 1) Physical property - mineralogy relationships developed for the Anuri kimberlite can be applied to other crater facies-dominated kimberlite pipes, especially of the Slave Craton, due to similarities in primary eruptive processes and secondary alteration processes. 2) Qualitative and quantitative relationships between physical properties and mineralogy discussed in this study for Kabanga, an intrusive magmatic sulfide deposit, are applicable for both intrusive and extrusive magmatic sulfide deposits, based on similar primary geologic processes and secondary serpentinization. 3) Geologic processes typical of crater facies-dominated kimberlite and magmatic sulfide deposits, including serpentinization and concentration of dense magnetic minerals with ore during emplacement, are also common to other ultramafic rock-hosted mineral deposits, such as mafic-ultramafic rock-hosted sapphire and ruby, chromite deposits, magmatic oxide deposits, Alaskan-type intrusions, etc. As such, qualitative physical property - mineralogy relationships resulting from primary and secondary geologic processes are likely applicable to other ultramafic rock-hosted mineral deposits: 4) The resolution of original geophysical surveys defines the maximum scale at which physical properties can be interpreted. This study will assess what level of detail can be gained from the analysis of mineralogy and physical properties, which in turn can be fed back into geophysical survey design. The quality of geophysical data available for a given deposit has a significant effect on the ability to detect physical property variations related to changes in mineralogy, and the ability to produce meaningful physical property models. Results of the work performed to accomplish these objectives are discussed for the kimberlite environment in Chapter 2 and the magmatic sulfide environment in Chapter 3, based on case studies of the Anuri kimberlite and the Kabanga magmatic sulfide deposit, respectively. Chapter 4 summarizes general conclusions of both ultramafic rock-hosted deposits and discusses implications towards interpretation of geophysical inversions. Chapter 5 discusses limitations of this study, addresses how this study resolved the objectives outlines above, and makes recommendations for further work. 7 Chapter 2; Understanding the Relationship between Physical Properties and Mineralogy within Diamondiferous Kimberlite through Geologic Processes 2.1 Introduction Exploration for kimberlite pipes is challenging because of their small footprint and recessive weathering characteristics (Leahy, 2001). Nonetheless, there are established techniques used during exploration for kimberlite pipes. Regional exploration for kimberlite pipes is focused along large-scale fault structures within Archean cratons. Indicator mineral mapping further identifies prospective areas, possibly locating individual kimberlite pipes or clusters of pipes (Gerryts, 1967; Pell, 1999). Once potential areas are identified, geophysical techniques aid the search by locating and defining spatial extents of individual pipes (Leahy, 2001). Geophysical data can be processed using inversion techniques to produce three-dimensional physical property models. These models can be interpreted with respect to rock type and mineralogy, given an understanding of relationships between physical properties and mineralogy. These relationships, however, are currently poorly developed and previous published work addressing this issue is scarce, making interpretation of physical properties with respect to mineralogy significantly more difficult. There is thus a need to understand the causes of physical properties in kimberlite pipes and how they relate to mineralogy, rock type, and potentially to diamond content, because of geologic processes. As diamonds occur in low concentrations in kimberlite, they do not contribute directly to physical properties of kimberlite pipes (Gerryts, 1970). The presence of diamonds in a kimberlite can be inferred from the presence of mantle xenocrysts, such as dense magnetic oxide minerals, due to sorting during kimberlite emplacement. Therefore, the relationship between physical properties and grade can be more complicated for kimberlite than for other mineral deposits where the ore minerals (e.g. sulfides) contribute directly to physical properties. The crater facies-dominated Anuri pipe (Figure 2.1), jointly owned by Kennecott Canada Exploration Inc. and Tahera Diamond Corporation, was chosen for study because it is characteristic of Slave craton kimberlite pipes in terms of morphology, country rock, and kimberlite facies (Power et al., 2004). It also has multiple intrusive kimberlite phases, a variety of bedded volcaniclastic kimberlite and country rock breccia, like many other Slave craton kimberlites. The findings of this study may be applied to other kimberlite pipes, as any causative dynamic processes involved in the distribution of magnetic oxide minerals and diamonds that 8 occurred in the Anuri kimberlite likely operated to some degree in other crater facies kimberlite pipes. Shallowly-eroded kimberlite pipes dominated by pyroclastic and volcaniclastic kimberlite, such as those of Saskatchewan and Alberta (Field and Scott Smith, 1999; Skinner and Marsh, 2004; Boyer, 2005), or kimberlite pipes that have predominantly been eroded to the deeper diatreme and hypabyssal facies, such as those of the Kaapvaal Craton (South African) kimberlite pipes, may differ from the Anuri kimberlite in morphology and dominant kimberlite facies, respectively, but physical property-grade relationships will still apply in the context of the geological processes that dominate these kimberlite pipes. Lastly, data is available for the Anuri kimberlite, including physical property measurements and diamond grades for all drillholes, and a cored drillhole through the western lobe that transects three subunits of the crater-facies volcaniclastic kimberlite breccia. Anuri H a c k e ^ ^ V 1 \r"rr 7 < dCShnmy^ River Y X i-J>-/-/ Lake A X Y v. v v rfi X X X ^ X x x %•{ X X X x ) X X x^x jx X X ^  X X ~ X X iffp / / / j x x x_^< x x x-x.1:)' / Anton' ' I xj if 'Terrene ' / / / / / / /////, / / "/ /j :<> f t /, Lac x x x x >V ' / / / / ' « x x x y / / ' ' ' ' /v f l f Sx x U/ / / ' ^/_l_iWGras xfk x xx! / / / / xi*-x-xUf...s.' • domain | \—Contwoyto Terrane I X X f.X X X X J< X X x •#"x,'*--x-| K X X X X X X X X Jx x Proterozoic | mobile belt i ' J HacT<eit\ | .x x x x x x x XYellowknifti v River H ' X X X X " X - X - X . . X " i x x x x x K X X X J _ X Great Slave Lake kilometres Figure 2.1: Location of the Anuri kimberlite with respect to the geological terranes of the Slave craton (location indicated in inset) and other kimberlite fields including the Lac de Gras field (Masun et al., 2004). 9 2.1.1 Objectives In order to meaningfully interpret geophysical data and three-dimensional physical property models with respect to rock type and diamond grade, this study aims to develop an understanding of the relationships between physical properties and mineralogy in the context of primary and secondary geologic processes. Accordingly, this study aims to: 1) Determine the nature of magnetic and dense mineral phases contributing to the susceptibility and density of the various kimberlitic lithologies; 2) Identify the origins of different dense magnetic phases based on composition and modes of occurrence, to determine how the minerals contributing to physical properties relate to concentrations of diamonds within a kimberlite pipe, due to geologic processes; 3) Characterize physical properties and grade characteristics of kimberlitic rock types, explaining variations in these features through differences in primary and secondary geologic processes. 2.2 Geophysical Characteristics of Kimberlite The geophysical characteristics of an unaltered kimberlite are a function of the amount and type of xenoliths that have been entrained during ascent from the mantle; the density and magnetic characteristics of the country rock (Power et al., 2004); the chemistry of the kimberlite magma; and the facies of kimberlite generated by different eruptive phases of kimberlite (Lecheminant, 1996; Mwenifumbo et al., 1996). Superimposed on the primary characteristics, post-emplacement processes, such as serpentinization and weathering, cause mineralogical changes (Leahy, 2001) that in turn affect physical properties and their distribution within a pipe (Arnott and Kostlin, 2003). To meaningfully interpret geophysical data in the form of physical property models with respect to mineralogy and rock type within kimberlite pipes, it is crucial to understand the interplay between primary and secondary influences on physical properties. Physical properties considered in this study are magnetic susceptibility (MS) and density, as magnetic and gravity surveys are commonly employed in exploration for kimberlite. Furthermore, susceptibility and density are most directly and simply related to mineralogy (Figure 2.2), increasing the potential of quantitatively estimating mineral abundances from these physical properties. 10 Diamond Chromite Magnetite Ilmenite Garnet Clay Serpentine 0.01 0.1 1 10 100 Magnetic Susceptibility (10~3SI) 1000 10000 100000 Figure 2.2: Range of densities and susceptibilities characteristic of the main minerals of altered kimberlite, as measured from minerals spanning a variety of geological occurrences. The constituent minerals of the Anuri kimberlite are expected to have the same characteristics. Data sourced from Telford et al (1990), Schon (2004), Dortman (1976), Parasnis (1979), Hunt et al. (1995), Clark (1997), and Bathelmy (2005). 2.2.1 Magnetism Magnetic methods, especially airborne surveys, are commonly used during kimberlite exploration (Leahy, 2001; Macnae, 1995a). Kimberlite pipes typically generate roughly circular magnetic anomalies due to their eruptive dynamics (MacNae, 1995a). This anomaly is represented either as a magnetic high or low depending upon the magnetic contrast between the kimberlite pipe and surrounding country rock (Power et al., 2004). A kimberlite may not be associated with a magnetic anomaly if there is no magnetic contrast between the country rock and kimberlite. Furthermore, anomalies associated with a single pipe might consist of complex magnetic subdomains, relating to different eruptive phases of the kimberlite (Lecheminant, 1996), each potentially with different diamond content (MacNae, 1995a). Magnetic anomalies related to kimberlite pipes can be described by two factors, spatial size and amplitude, which are in turn controlled by characteristics that are specific to each pipe. The spatial size of an anomaly is proportional to pipe diameter (Lecheminant, 1996). Kimberlite pipe 11 dimensions vary from 100 to 1600 m (Keating, 1996), thereby creating distinctly different anomaly sizes. The amplitude of a magnetic anomaly is proportional to magnetic susceptibility of the kimberlite (Lecheminant, 1996), which itself is highly variable (Table 2.1). Magnetic variations between pipes result from differences in magnetic mineral textures (Hunt et al., 1995), compositional and evolutionary differences in the kimberlite magma that affect the magnetic oxide minerals, and different mantle-to-surface transport conditions that may change the magnetic oxide mineralogy (Arnott and Kostlin, 2003). Identifying these magnetic oxide minerals and understanding the processes affecting them is crucial to understanding the magnetic properties of kimberlite. Table 2.1: Comparison of the fades, magnetic susceptibility and density of kimberlite pipes throughout the world. Location of Facies Susceptibility (KT5 SI) Density (g/cmJ) Kimberlite Kirkland Lake Hypabyssal 2.5 - 31 A1 3.111 2.1 -2.6 1 Sturgeon Lake Hypabyssal 0.8-3.72 Fort a la Come Crater 0.6-401 Northwest Territories Crater <7.52 Somerset Island Diatreme 2.5-36 2 Yakutia 0.13-75.42 Africa All 0.5-4 4 Lesotho 0.63 - 75.42 Sierra Leone 2.47-3.123 South Africa 2.64-2.983 1 Richardson et al., 1995; 2 Katsube et al., 1992; 3 Gerryts, 1967; 4 Arnott and Kostlin, 2003. 2.2.1.1 Magnetic Mineralogy Magnetization of kimberlite varies with the degree of magmatic differentiation (Arnott and Kostlin, 2003), due to the crystallization of fine-grained spinel in the groundmass. With increased crystallization, spinel evolves from aluminous magnesian chromite through titaniferous magnesian chromite (termed "magmatic trend 2", Figure 2.3), to strongly magnetic magnesian ulvospinel-ulvospinel-magnetite series (termed "magmatic trend 1", Figure 2.3) (Mitchell, 1995). Thus, kimberlite becomes more magnetic as the magma progressively crystallizes, due to the production of magnetic spinel in magmatic trend 1. The last magnetic mineral of significance is ilmenite. Ilmenite in kimberlite occurs as mega/macrocrysts, at least some of which as xenocrysts liberated from disaggregated mantle xenocrysts. It typically has 50-90 mol% MgTiCh, 5-10 mol % hematite (FeaCu), elevated Cr203 (1 - 7 wt%), and low M n (< 1 wt%) (Mitchell, 1986; Mitchell, 1995). The magnetic 12 susceptibility of ilmenite depends on the titanium (Ti) content relative to iron (Fe), as high titanium contents in ilmenite lower susceptibility (Macnae, 1995b). 0 0.2 0.4 0.6 0.8 1 Fe^Mg+Fe 2*) 2.2.1.2 Volcanic Facies and Magnetism An idealized kimberlite pipe consists of three facies that reflect large-scale differences in eruptive processes (Clement and Skinner, 1985; Power et al., 2004). These are broadly known as hypabyssal, diatreme and crater facies (Figure 2.4). Intrusive crystallization of kimberlite magma leads to hypabyssal kimberlite (HK) facies, whereas pyroclastic eruption of the magma creates crater facies volcaniclastic kimberlite (VK) (Mitchell, 1986; Skinner and Marsh, 2004). The diatreme facies represents lower temperature, non-violent emplacement involving extensive mixing of magmatic clasts, country rock fragments, and mantle-derived xenoliths (Mitchell, 1986) by fluidization and potential resettling (Skinner and Marsh, 2004; Field and Scott Smith, 1999). The diatreme facies separates the intrusive hypabyssal from the extrusive crater facies. 13 Crater Facies (volcaniclastic kimberlite) Diatreme Facies (tuffisitic kimberlite breccia) Hypabyssal Facies Figure 2.4: Schematic diagram of facies within an idealized kimberlite. Modified after Hawthorne (1975). The primary eruptive and resedimentation processes forming the three kimberlite facies can result in different mineral assemblages and textures (Mitchell, 1986). As such, magnetic susceptibility might be expected to vary between kimberlite facies in a single pipe. However, there is no compelling information that indicates whether or not susceptibility correlates with volcanic facies. For example, Mwenifumbo et al. (1996) show that susceptibility is lower in diatreme facies kimberlite than hypabyssal kimberlite in Kirkland Lake kimberlite pipes. Conversely, other studies (Lecheminant, 1996; Katsube and Kjarsgaard; 1996) find that susceptibility does not vary with kimberlite volcanic facies, based on a compilation of 41 Canadian kimberlite pipes. Variations in susceptibility are considered in some circumstances to be indicative of differences in diamond grade. Katsube and Kjarsgaard (1996) argue that primary magnetite, the main contributor to high susceptibility, crystallized from the magma under relatively high 14 oxygen fugacity.conditions, which promotes diamond corrosion (McCammon et al., 2001; Fedortchouk, 2004). High susceptibility may then be related to low diamond content if magnetite is a primary phase. Conversely, if magnetite results from a secondary process, such as serpentinization, there is no reason to predict low diamond content. Identifying dense and magnetic minerals and how they relate to diamond content through geological processes in each kimberlite facies can therefore lead to more meaningful interpretations of physical properties with respect to mineralogy. 2.2.1.3 Alteration Post-emplacement alteration is ubiquitous in kimberlite pipes, although variable in degree. Alteration occurs because kimberlite is porous and its mineralogy is unstable under surface conditions (Macnae, 1995a). Alteration results in production of secondary oxide minerals and alteration of primary oxide minerals to phases with different susceptibilities (e.g. non-magnetic iron oxides) (Macnae, 1995b). In particular, serpentinization, a pervasive and intrinsic process in kimberlite, creates serpentine and magnetite upon destruction of ferromagnesian minerals, drastically increasing susceptibility (Clark, 1997; Measday, 2004). Although some fine-grained serpentine is produced during ascent of the magma to surface (Mitchell, 1995; Norton and McCandless, 1995), pervasive serpentinization can occur immediately after eruption as meteoric water and groundwater permeate the kimberlite pipe (Leahy, 2001). The consequences of alteration processes, particularly serpentinization, on physical properties of kimberlite are undeniable and further study is required to fully understand and potentially quantify these effects. 2.2.1.4 Remanence Remanent magnetism is common in kimberlite pipes and significantly complicates the interpretation of magnetic anomalies (Clark, 1987; Hargraves, 1989; Thurston, 2001; Arnott and Kostlin, 2003; Power et ah, 2004). For kimberlite, large degrees of magnetic remanence can be attributable to the presence of titanomagnetite, hematite (Thurston, 2001) and fine-grained magnetite (Clark, 1995). Remanence can result in a kimberlite appearing as either a magnetic low or high. Where remanent magnetism dominates, the induced magnetization and remanence polarities are both 15 normal, and the net result is a strong and normal magnetization. In contrast, where remanent magnetism is strong and has a reversed polarity to the induced magnetization, the net result is a strong negative magnetic anomaly. In the unusual case where the magnitude of remanent magnetism is approximately equal to the induced magnetization but opposite in direction, the resulting magnetization is almost zero. A kimberlite may then be "invisible" in magnetic data (Lockhart, 2004). Thus, remanent magnetism can significantly change the geophysical expression of a kimberlite pipe, making the interpretation of physical properties in a kimberlite difficult, if not impossible, in certain cases. 2.2.2 Density The expression of kimberlite pipes in gravity data depends both on the degree of alteration of the kimberlite, the dominant facies of the kimberlite, and the density of the country rocks. Pervasive alteration of kimberlite mineral constituents (e.g. olivine and pyroxene) to serpentine and clay reduces density. (Gerryts, 1970), causing altered kimberlite pipes to occur as gravity lows within higher density granitoid and metasedimentary host rocks (Paterson et al., 1977; Lock, 1985; MacNae, 1995a; Power et al., 2004). Conversely, small gravity highs have locally been reported over unweathered kimberlite occurring in sedimentary rocks (Paterson et al., 1977), such as those at Fort a la Corne, Saskatchewan (Richardson et al., 1995), and Kirkland Lake, Ontario (Mwenifumbo et al., 1996). Different kimberlite volcanic facies tend to have characteristic densities and porosities (Arnott and Kostlin, 2003) (Table 2.2). The lowest densities are associated with crater facies volcaniclastic material, which consists of porous tuffaceous and brecciated material that is more susceptible to alteration (MacNae, 1995a; Katsube et al., 1992). As such, distinct gravity lows have been recorded over crater facies kimberlite pipes, such as the Mwadui pipes in Tanzania (Gerryts, 1970), while much smaller gravity lows have been measured over diatreme facies kimberlite (Burley and Greenwood, 1972). In contrast, intrusive crystallization causes hypabyssal facies kimberlite to have higher bulk density and lower porosity than crater facies kimberlite (Arnott and Kostlin, 2004; Richardson et al., 1995). Thus, gravity signatures and density anomalies are directly related to the dominant kimberlite facies. 16 Table 2.2: Density characteristics of the different kimberlite facies, as measured from Siberian kimberlite pipes (Arnott and Kostlin, 2003). Kimberlite Facies Density (g/cm3) Hypabyssal 2.4-2.9 Crater 1.4 Breccia 2.2-2.4 Weathered breccia 1.8 2.3 Geology 2.3.1 Regional Geology The Anuri kimberlite (Figure 2.1) intrudes the northwestern edge of the 200,000 km 2 Archean Slave craton (Masun et al., 2004). The Slave craton is predominantly a granite-greenstone terrane comprised of numerous greenstone belts of metavolcanic and metasedimentary rocks, intruded by syn- and post-volcanic granitoid plutons (Fyson and Helmstaedt, 1988; Padgham, 1992). Volcanic rocks include tholeiitic mafic to felsic packages, which are increasingly common towards the western edge of the Slave craton, and calc-alkaline intermediate series packages that are more abundant towards the east (Fyson and Helmstaedt, 1988; Percival, 1996; Davis et al., 2003). These volcanic rocks are overlain by turbiditic greywacke with minor conglomerate and sandstone derived from the volcanic terranes (Fyson and Helmstaedt, 1988; Hoffman, 1989; Lecheminant, 1996). Several Archean deformation episodes, evidenced by thrust faults, polyphase folds and late faults, have created a north-trending structural architecture (Fyson and Helmstaedt, 1988; Hoffman, 1989; Lecheminant et al., 1996; Percival, 1996). Proterozoic dyke swarms have intruded the Archean rocks (Lecheminant et al., 1996; Percival, 1996). Phanerozoic sedimentary rocks were deposited oyer the Precambrian rocks. The entire tectonostratigraphic sequence was present when the Anuri kimberlite erupted. The Phanerozoic sedimentary rocks have subsequently been eroded (Pell, 1997) and are preserved as xenoliths within the volcaniclastic kimberlite pile. 2.3.2 Geology of the Anuri Kimberlite The Anuri kimberlite is hosted by metamorphosed dioritic to granitic rocks, minor gneiss and migmatite, rare pegmatite dykes, and numerous mafic dykes. Presently, the felsic crystalline 17 rocks are overlain by approximately 30 m of sedimentary rock shattered by glaciation and by Pleistocene boulder till. As the kimberlite is recessive, it lies beneath a lake (Masun et al., 2004). The 613 ± 6 Ma (Rb-Sr on macrocrystal phlogopite (Masun et al., 2004)) Anuri pipe has an ovoid surface area of 4-5 ha that is elongated in an easterly direction, based on drilling and geophysics. Definition drilling has shown that the Anuri kimberlite is an inverted cone-shaped volcanic edifice with sides dipping inward at 75-85°. The pipe is filled with fragmental volcaniclastic kimberlite breccia (VKB) to a known depth of at least 175 m (Masun et al., 2004). The Anuri kimberlite is considered to comprise two separate pipes that coalesce approximately 150 m beneath the present surface (Figure 2.5). Separate kimberlite eruptions are believed to have formed the two lobes, based on different proportions, types, and alteration of crustal-derived xenoliths in each lobe. Furthermore, kimberlite facies, character of mantle xenocrysts, groundmass spinel compositional trends, susceptibility and diamond distributions vary between lobes. The western lobe has lower magnetic susceptibility, more restricted macrocryst:microcryst ratios and more diamonds per 100 kg, suggesting that it is sedimentologically well-sorted in terms of diamonds (Masun et al., 2004). Higher diamond contents within the western lobe, based on the current state of exploration (2006), make it more interesting economically than the eastern lobe (Masun et al., 2004). W E 400m N Figure 2.5: Schematic cross section of the Anuri kimberlite, showing the western lobe infilled with volcaniclastic kimberlite breccia (VKB) and the dominantly hypabyssal facies eastern lobe. Black lines indicate the path of drillholes. The drillhole studied (LT508-1) is outlined by a black box. Modified after Masun et al. (2004). 18 2.3.2.1 Volcanic Kimberlite Facies Hypabyssal facies rock, classified as a macrocrystic hypabyssal phlogopite spinel kimberlite (Table 2.3), dominates the eastern lobe (Figure 2.5) to a depth of at least 240 m. Macrocrystal and phenocrystal groundmass olivine populations within the hypabyssal rocks have been entirely replaced by serpentine and carbonate minerals (Masun et al., 2004). The western lobe (Figure 2.5) is filled with crater-facies volcaniclastic kimberlite breccia (Table 2.3), composed of a variety of xenoliths and xenocrysts (crustal or mantle-derived garnet, chrome diopside, and spinel) and macrocrystal olivine set in a fine-grained matrix. Variations in the proportion and size of xenoliths, xenocrysts and macrocrysts, and proportion of matrix suggest the presence of poorly-graded units within the pipes. The rocks are poorly bedded, although elongated constituents are imbricated in several narrow (< 1 cm) intersections of drill core. Alteration mineral phases include serpentine, carbonate, clay, and iron oxide minerals. Most primary mineralogy and textural features have been obliterated (Masun et al., 2004). Table 2.3: Description of rock types identified in the Anuri kimberlite (Masun et al., 2004)5. Facies Texture Mantle Macrocrysts/ Magma- Crustal xeno- Phenocrysts clasts Xenoliths liths Hypabyssal kimberlite Fine grained, crystalline Olivine, phlogopite, oxide minerals Phlogopite, spinel, minor calcite, serpentine, apatite Granitoids, mafic dykes, Protero-zoic seds. <5% 0) 0) JO E '2 o "•S3 in w o "c CO o o > (Heterolithic) volcaniclastic kimberlite breccia Normal graded beds, undulating bedding contacts, crude sorting 1-5% 20-35% macrocrysts 5-10% magma-clasts 10-50% crustal xenoliths (Autolithic) magmaclastic volcaniclastic kimberlite breccia Massive 5-7% Up to 40% magma-clasts <10% xenoliths Finer grained volcaniclastic kimberlite breccia Massive <2% 10-25% macrocrysts 5-10% magma-clasts 15% xenoliths Lithic Breccia Closely packed, angular fragments 5% magma-clasts 95% xenoliths Mantle xenoliths include garnet, chrome diopside, and spinel. Crustal xenoliths are locally derived from granitoid basement rocks and Proterozoic sediment cover rocks, with less common clasts of mafic dyke that are 1-10 cm in size in the volcaniclastic lithology. Pyroclastic juvenile lapilli magmaclasts range in size from 0.1-1 cm, though the size and abundance of these clasts decreases with depth. 19 Within the crater facies kimberlite, four subtypes of kimberlite have been identified (Figure 2.6, Table 2.3). Heterolithic volcaniclastic kimberlite breccia (HVKB or V K B ) is the most abundant lithology, as it is present in both lobes of the Anuri kimberlite. It consists predominantly of olivine macrocrysts and a variety of autoliths (magmaclasts), mantle xenocrysts and crustal xenoliths, crudely sorted into horizons. Autolithic volcaniclastic kimberlite breccia (AVKB) is limited to the upper portion of the western lobe. It is dominated by magmaclasts, has a greater amount of mantle xenoliths than the other volcaniclastic kimberlite breccias and lacks evidence of sedimentation, such as grading and bedding. Fine-grained volcaniclastic kimberlite breccia (FVKB) is restricted to the upper portions of the eastern lobe, where it is intercalated with and grading into V K B . It is finer grained than the other volcaniclastic kimberlite breccias. Lithic breccia (LB) occurs as laterally discontinuous lenses where the two lobes join, and is proposed to have formed by pipe-wall collapse (Masun et al., 2004). The drillhole available for this study (LT508-1) transected autolithic and heterolithic volcaniclastic kimberlite breccia and lithic breccia within the western lobe. Diamond grade and susceptibility data was available for other drillholes throughout both lobes. Because the Anuri kimberlite consists predominantly of altered volcaniclastic crater-facies kimberlite and it is hosted by higher density granitoid and metasedimentary host rocks, it occurs as a low-density anomaly within gravity data (Figure 2.6A). In magnetic data, the Anuri kimberlite appears as a break in a magnetic diabase dyke (Figure 2.6B). Figure 2.6: Results from geophysical surveys conducted over the Anuri area (unpublished data, Masun et al., 2004). A) Bouguer Gravity, density = 2.67 g/cm3. B) Airborne total field magnetics. The Anuri kimberlite is projected to surface (black line). 20 2.3.2.2 Formation of the Anuri Kimberlite The Anuri kimberlite is interpreted to have formed by an initial magma intrusion during the Neoproterozoic that did not breach the surface. As such, the magma crystallized as hypabyssal kimberlite of the eastern lobe (Figure 2.7). A second kimberlitic magma subsequently intruded, explosively breached the surface, and excavated the main pipe. The pipe was filled with pyroclastic material. Crater rim deposits formed and were later resedimented into the pipe. Lastly, the top of the pipe was gradually eroded to its current level (Masun et al., 2004). a Neoproterozoic b Water & Overburden J Prolerozoic Sediment Cap • Archean KZ^flExtra C r a t e r B r e c c l a t e d i ; ^ IFragnwitiof Basement Deposits [<if&3 Country Rock LfjJ Country Rock Figure 2.7: Sequential steps in the formation model of the Anuri kimberlite, as proposed by Masun et al., 2004. A) Intrusion of an initial kimberlite magma that does not breach the surface, thus forms hypabyssal kimberlite (HK). B) Intrusion of a second batch of kimberlite magma. C) The second kimberlite magma explosively breaches the surface and excavates the crater of the western lobe, creating crater rim deposits that are later resedimented back into the excavated crater as volcaniclastic kimberlite (VK) breccia. D) Subsequent erosion of the kimberlite and deposition of overburden. 21 2.4 Integrating Physical Properties, Mineralogy and Grade: Preliminary Work Preliminary analysis of the relationship between physical properties and mineralogy with respect to primary and secondary mineral phases was conducted by Pretorius (2003). Alteration phases, quantified by Rietveld analysis and a Portable Infra-red Mineral Analyzer (PIMA) for a small data set, showed no discernable correlation with magnetic susceptibility or kimberlite facies (Table 2.3). Pretorius (2004) suggests that the lack of relationship between alteration mineralogy and magnetic response indicates that susceptibility is controlled by modal abundance and chemistry of primary magnetic oxide minerals (Table 2.4), such as the ubiquitous kimberlitic spinel-series oxide minerals. Table 2.4: Hydrous/alteration minerals identified based on PIMA spectra in the Anuri LT508-01 drillhole as a function of depth, magnetic susceptibility and kimberlite facies6. Depth Mont- Talc Anti- Horn- Other Susceptibility (10* SI) Density Kimberlite (m) morillonite gorite blende (g/cm3) Facies 108 Present Present Present 12.2 2.39 AVKB 130.9 48% 22% 30% 5.89 2.49 AVKB 149 8% 32% Water 3.29 2.46 HVKB 169.5 Present Present Present 3.78 2.46 HVKB 175.9 68% 32% 5.5 2.42 HVKB 190.9 60% 24% 14% 3.16 2.38 HVKB 201.7 56% 18% 25% 3.62 2.40 HVKB 206 53% 31% 16% 12.2 2.43 HVKB 220.9 53% 26% 21% 8.19 2.41 HVKB 224 Present 24.4 2.44 HVKB 242 Present Present Present 6.97 2.53 LB 258.9 Present Present 3.95 2.52 LB 6 A V K B is autolithic volcaniclastic kimberlite breccia, H V K B is heterolithic volcaniclastic kimberlite breccia, and L B is lithic breccia dominantly composed of crustal xenoliths. "Present" means that P I M A identified the mineral in the sample but its abundance was not quantified. Initial work with diamond grade and magnetic susceptibility data provided by Kennecott Canada Exploration Inc (Appendix A) shows consistent positive correlations between macrocryst ( > 1 mm in diameter) :microcryst (< 1 mm in diameter) diamond ratios and magnetic susceptibility within individual volcaniclastic kimberlite breccia beds in both lobes of the Anuri kimberlite (Figure 2.8). This correlation implies that the larger stones were sorted together with the dense magnetic oxide minerals by sedimentary processes (Pretorius, 2004). Furthermore, normal grading is suggested by increasing macrocryst: microcryst ratio with depth within individual beds of the western lobe (LT508-1). Normal grading commonly results from sediment deposited by density settling, such as from suspension in water or airfall from a 22 pyroclastic column. By contrast, reverse grading, typical of mud/debris flows, is indicated by decreasing macrocryst:microcryst ratio with depth within individual volcaniclastic kimberlite breccia beds of the eastern lobe (LT508-8). Given that the macrocryst:microcryst ratio reflects a geological process, different modes of grading suggests that different processes formed the western and eastern lobes of the Anuri kimberlite. * in £• u 2 o 2 a 0.1 n u 2 o a 0.01 • LT508-01 XLT508-08 > 82.5 128 VKB 123.15 y 1 0 7 2 101.75 X 76.6 42.1 91 X9 6 4 FVKB " X 8 1 2 5 212 86.1 VKB 97.5 178.5 " X X"l33 X V K B ^ ^ ^ " LVKBB m 113 227 i 146 208 102.5 231 117.5 Direction of grain size fining 14! • 131 ^ Depth within * 108 drillhole 10 Magnetic Susceptibility (10 SI) 204 12 Figure 2.8: Plot of macrocryst:microcryst diamond ratios versus magnetic susceptibility, in drillholes LT508-01 and LT508-08. Individual graded beds can be distinguished, exhibiting either reverse (high macrocryst:microcryst diamond ratios at the top of a bed) or normal grading (high macrocryst:microcryst diamond ratios at the bottom of a bed) due to different sedimentary processes. Macrocryst:microcryst ratios and stones/100 kg for the LT508-1 samples (Figure 2.9) appear to be inversely related, with slight variations in slope. The portion of this trend with the shallowest slope is dominated by low susceptibility ((2 - 4.5) x 10"3 SI) samples. In contrast, 3 * i steeper portions of the main trend consist predominantly of moderate ((4.5 - 7) x 10" SI) to high (> 7 x 10"3 SI) susceptibility samples. The significant change in slope corresponds to a change in kimberlite facies from autolithic V K B (shallow) to heterolithic V K B (deep). Hence, in the LT508-01 drill hole, there is very good correspondence between susceptibility, diamond distribution and kimberlite facies. 23 0.3 • 0.25 O • 4) Average susceptibility = 8-11 • Average susceptibility = 4.5-7 X Average susceptibility = 2-4.5 .4 AVKB 0 50 100 150 200 250 300 350 Stones per 100 kg Figure 2.9: Macrocryst (>1 mm): microcryst (<1 mm) ratio versus stones/100 kg for the LT508-1 drillhole through the Anuri kimberlite, with the average magnetic susceptibility of each depth interval (in metres) expressed in colour (as 10'3 SI). The black arrows refer to the steep and shallow trends within the macrocryst:microcryst - stones/100 kg data, and the break in slope between the two, as discussed in the text. 2.5 Analysis of Magnetic Mineral Phases To determine the relationship between physical properties and diamond content, it is essential to understand which dense and/or magnetic minerals controlling physical properties within the Anuri kimberlite were produced or emplaced by primary and secondary geological events. Dense minerals, such as magnetic oxide minerals, present during primary geological processes should be spatially related to diamonds since they underwent the same physical processes of entrainment, eruption and sedimentation. In contrast, minerals resulting from secondary processes are likely unrelated to diamonds. Dense and magnetic minerals occurring within the Anuri kimberlite predominantly include ilmenite and spinel, which ranges in composition from chromite to magnetite. Ilmenite occurs as mega/macrocrysts in the kimberlite (Table 2.5 and Figure 2.10). Spinel occurs as: 1) mantle xenocrystic chromite; and 2) Fe-Al-Ti-rich spinel evolving towards magnetite that crystallized from the kimberlite magma. Both xenocrystic ilmenite and chromite can be used as direct 24 proxies for diamond, since they originated from the mantle and underwent similar magmatic disaggregation and eruptive processes. Magnetite also occurs within crustal xenoliths and as a secondary mineral formed during serpentinization, making its relationship with diamonds complex. Susceptibility of magnetite is orders of magnitude larger than that of ilmenite or chromite/spinel, so the abundance of magnetite likely controls susceptibility. Table 2.5: Summary of the occurrences of magnetic mineral phases 7 . Oxide Form Size (pm) Habit Alteration Occurrence Magnetite Anhedral to subhedral 75-150 Lensoid to equant to worm-like None Intergrowths with silicates Anhedral Very fine Irregular Mantling olivine macrocrysts Anhedral to subhedral Fine to 50 Equant or lensoid Within crustal xenoliths Titano-magnetite Subhedral Anhedral Up to 300 Rufile along rims and cleavage Outer rim of rutile Macrocrysts Innermost alteration rim on ilmenite Chromite Subhedral Anhedral 100-250 Very fine Locally broken Irregular, worm-like Titano-magnetite then rutile Macrocrysts Cutting silicate cleavage Within altered olivine Ilmenite Anhedral 100-1000 Equant to irregular Atoll of Ti-magnetite, locally then rutile Macrocryst Subhedral Up to 500 Irregular grain or aggregate nidentified, on rims and cleavage Macrocryst Textures as observed during the scanning electron microscope study prior to the microprobe work. t 25 Figure 2.10: Photomicrograph of kimberlite showing textural characteristics of magnetic minerals in the Anuri pipe. A) Magnetite commonly occurs as lenses along the cleavage of silicates, whereas chromite occurs as worm-like intergrowths within the silicates and cutting cleavage. Ilmenite occurs as irregular coarse atoll grains. Large black dots are pen marks used during SEM work. B) Ilmenite core grain (light grey) with inner (dark) rim of rutile and outer (white) rim of titanomagnetite. 26 2.5.1 Quantification of the Magnetic Mineral Phases 2.5.1.1 Method For the three kimberlite facies transected by the available drillcore ( A V K B , H V K B , and LB) samples of both low and high magnetic susceptibility zones from each lithology were crushed (Table 2.6). Heavy minerals were then concentrated on a Wilfley table, and sieved into three size fractions. A hand magnet was used to separate highly magnetic grains from each size fraction of each sample. A Frantz Isodynamic Magnetic Separator further separated the heavy minerals into semi-magnetic and non-magnetic portions (Figure 2.11). Table 2.6: Magnetic susceptibility, volcanic facies, stones/100 kg and macrocryst:microcryst ratios (mac:mic) for the intervals studied from the LT508-1 drill core8. Susceptibility (10 J SI) Density (g/cmJ) Depth (m) Average Standard Deviation Average Standard Deviation Stones/ 100kg Macrocryst: microcryst Lithology 108 39.03 1.30 2.46 0.02 230.00 0.05 AVKB 130.9 5.06 0.20 2.52 0.05 183.67 0.06 AVKB 203 11.15 0.25 2.35 0.20 95.24 0.11 HVKB 248 0.33 0.14 2.58 0.09 104.76 0.10 HVKB/LB 251 12.75 0.37 2.48 0.02 68.63 0.17 LB 258.9 6.17 0.21 2.45 0.02 110.00 0.10 LB These sections were chosen in the pilot study (Pretorius, 2004). A V K B is autolithic volcaniclastic kimberlite breccia, H V K B is heterolithic volcaniclastic kimberlite breccia, and L B is lithic breccia dominantly composed of crustal xenoliths. Lithology _L 1 Low Magnetic Susceptibility ! Wilfley Concentrate Fine Grained Medium Grained Coarse Grained Magnet Frantz Non-magnetic Probed Figure 2.11: Schematic flow diagram illustrating sample preparation for mineral phase analysis of the three lithologies: autolithic VKB, heterolithic VKB and lithic breccia. A high and low susceptibility section was chosen from each lithology to be processed and analysed. The magnet subdivision refers to the grains removed using a hand magnet. The Frantz subdivision refers to the grains removed using the Magnetic Frantz Separator at 0.3 A. The non-magnetic subdivision refers to all of the remaining grains. 27 Both the magnet and Frantz separates of the middle size fraction of each sample were then chosen for further work, because the grains were sufficiently large to give accurate microprobe data, while still being small enough to obtain a sufficient sample size. On the electron microprobe, 50 grains from the hand magnet and Frantz separates of the six samples were compositionally analyzed using the electron microprobe (Figure 2.11; Appendix B, C and D). Resulting compositional data were processed to identify ilmenite, chromite or magnetite, based on titanium and chromium contents (Table 2.7). Table 2.7: Summary of the number of grains analyzed from each lithology that were chromite, ilmenite and magnetite9. Sample Facies Susceptibility Separate # Chromite # Magnetite # llmentite % (10 3 SI) AN 108 AVKB 39.03 Magnet 4 1 45 0.6 AN 108 AVKB 39.03 Frantz 3 0 47 0.6 AN130.9 AVKB 5.06 Magnet 2 10 38 1.2 AN130.9 AVKB 5.06 Frantz 3 0 47 1.2 AN203 HVKB 11.15 Magnet 13 0 37 0.1 AN203 HVKB 11.15 Frantz 1 6 43 0.1 AN248 HVKB 0.33 Magnet 11 13 26 0.7 AN248 HVKB 0.33 Frantz . 1 0 49 0.7 AN251 LB 12.75 Magnet 5 38 7 1.5 AN251 LB 12.75 Frantz 5 36 9 1.5 AN258.9 LB 6.17 Magnet 5 39 4 1.6 AN258.9 LB 6.17 Frantz 7 16 25 1.6 A V K B is autolithic volcaniclastic kimberlite breccia, H V K B is heterolithic volcaniclastic kimberlite breccia, and L B is lithic breccia. The % column was calculated from the weight of the magnetic heavy fraction to the weight of the remaining grains, multiplied by 100, thus representing the approximate amount of these magnetic oxide minerals within the kimberlite. Samples with high susceptibility appear in black, and those with low susceptibilities are in grey. 2.5.1.2 Results The abundance of magnetic minerals within each lithology likely has a significant effect on the susceptibility and density between lithologies. Relative proportions of magnetic minerals for the low and high susceptibility samples of each rock type were quantified (last column in Table 2.6) after the compositional analysis was performed using the electron microprobe. The volume of magnetic minerals differs drastically between samples, and between susceptibility regions of the samples (Table 2.7). However, there are large uncertainties on the proportions since unknown volumes of material were removed from each sample during processing and for the compositional analysis. Magnetic mineral contents also differed between size fractions, with the finest size fractions typically having considerably more grains. Most grains analyzed from the heterolithic and autolithic volcaniclastic kimberlite breccia (VKB) lithologies are ilmenite (Table 2.7). High susceptibility regions of each volcaniclastic 28 kimberlite breccia lithology have more chromite and ilmenite than the low susceptibility regions. Unexpectedly, high susceptibility regions of the VKB lithologies have fewer magnetite grains than the low susceptibility regions. Magnetite primarily occur as fine grains, which was also observed during petrographical analysis, thus they are likely more abundant in the fine size fraction. This may explain why magnetite is not the dominant phase within the high susceptibility regions of the volcaniclastic kimberlite breccia. Magnetic oxides of the lithic breccia are predominantly magnetite, with more magnetite being present in the high susceptibility sample. 2.5.2 Composition of Magnetic Oxide Minerals and Application to Origins Several studies (Mitchell and Meyer, 1987; Mitchell, 1995; Barnes and Roeder, 2001; Wyatt et al., 2004) have defined criteria for identifying whether ilmenite and spinel are kimberlitic in origin based on composition (Appendix B, C and D). These criteria were applied to the magnetic oxide analyses collected for Anuri to determine the proportion of oxide minerals originating from kimberlitic sources, as opposed to occurring within crustal xenoliths or resulting from secondary processes. The origins of these magnetic oxide minerals will dictate how they, and the physical properties resulting from concentrations of these minerals, relate to concentrations of diamonds. 2.5.2.1 Ilmenite Based on the experimental kimberlitic ilmenite line defined with respect to Ti02 and MgO concentrations (Wyatt et al., 2004), ilmenite in the Anuri pipe is predominantly kimberlitic (Figure 2.12). Analyses from a few grains lie within non-kimberlitic fields. These non-kimberlitic ilmenite grains are largely within the magnet fractions of the low susceptibility region of the autolithic VKB, suggesting that they are more magnetic than the kimberlitic ilmenite. The non-kimberlitic ilmenite likely originated from crustal xenoliths. Local compositional clustering might imply that either an individual ilmenite grain was crushed into many grains or several grains of similar composition originated from one xenolith. 29 MgO vvt% Figure 2.12: Plot of the T i 0 2 wt% vs. MgO wt% of the ilmenite sampled from three of the lithologies available in the Anuri kimberlite. The vast majority of ilmenites fall within the kimberlite range. Modified after Wyatt et al. (2004) 2.5.2.2 Spinel The composition of Anuri spinel are plotted relative to trends defined by Mitchell (1986) and fields determined by Barnes and Roeder (2001) (Figure 2.3 and 2.13). Many of the grains defined as chromite fall along "magmatic trend 2" (Mitchell, 1986), the Ti-magnetite trend that is not unique to kimberlite (Figure 2.3). However, these chromite grains also plot within the primary kimberlite chromite field (Figure 2.13), and thus they are likely kimberlitic in origin. Relatively few grains defined as magnetite plot along "magmatic trend 1" (Figure 2.3), the magnesian-ulvospinel-magnetite trend that is characteristic of kimberlite. Most magnetite analyses plot within the late stage serpentinization-related magnetite field (Figure 2.13), with the composition of some magnetite grains trending towards the chromite macrocryst field along the kimberlite trend. 30 A l 3 + Primary kimberlite Cr chromite Figure 2.13: Ternary diagram illustrating the composition of spinels from Anuri, with respect to genetic fields defined from study of other kimberlite spinels (Barnes and Roeder, 2001). 2.6 The Relationships between Physical Properties and Diamond Grade Correlations between physical properties, rock type and grade were studied to assess whether quantitative relationships can be established between physical properties and mineralogy (Appendix F and G). Grade and physical property distributions were characterized for each lithology and explained using the primary and secondary processes that formed the different rock types. Lastly, physical properties were characterized for high-grade rocks, potentially allowing for assessment of ore content from physical properties. Magnetic susceptibility was measured at 1 m intervals along the LT508-1 drillhole. Density of the LT508-1 core was measured for small (< 1 m) homogenous intervals (typically three to four petrologically similar samples) for the entire length of the core. Magnetic susceptibility and density were then averaged over the same depth intervals that the samples were crushed over for stones/100 kg and macrocryst:microcryst assessment. 2.6.1 Physical Properties and Lithology The relationship between physical properties and rock type, as a manifestation of various primary and secondary physical properties, is straightforward. Each lithology studied has a distinct range of susceptibility and density values (Table 2.8; Figure 2.14). Hypabyssal kimberlite within the Anuri kimberlite has low susceptibility and a wide range of densities. Lithic breccia has high density and moderate susceptibility. No data are available for the fine-grained VKB. Heterolithic VKB samples show a large range of densities and susceptibilities, but tend to have low densities and high susceptibilities. Autolithic VKB tends to have low susceptibility and moderate density. There is some potential for the rock type to be inferred directly from three-dimensional physical property models produced by inversions. However, limited data was available for this study, thus the level of confidence associated with these physical property characteristics is relatively low. Table 2.8: Summary of physical property and grade statistics 1 0 (average and standard deviation (st dev)) for lithologies of the Anuri kimberlite. Magnetic Susceptibility . (10-3SI) D e n s l Average D e , n s i £ Stones/100 kg "JgZSE (g/cm ) a microcryst St Dev AVKB 6.2 +9.76 -3.91 2.46 0.02 177 63.58 0.07 0.07 HVKB 9.9 +12.83 -7.66 2.42 0.02 153 46.34 0.08 0.08 Lithic Breccia 13.2 +22.08 -7.84 2.55 0.07 94 22.53 0.07 0.07 Hypabyssal 15.2 +34.75 -6.63 2.32 0.02 84 22.44 0.04 0.06 1 0 Statistics for magnetic susceptibility were calculated for a lognormal distribution. Statistics for density, stones/ 100kg and macrocryst:microcryst were calculated for normally distributed data. 32 100 V) f o 10 Q. 0) u • 3 to u 5 c • S 2.25 / A A* • Autolithic VKB • Heterolithic VKB O Lithic Breccia AHypabyssal Kimberlite ? • • 2.3 2.35 2.4 2.45 Density (g/cm3) 2.5 2.55 2.6 Figure 2.14: Plot of magnetic susceptibility and density characteristics of many lithologies of the Anuri kimberlite. Ovals are used to identify the general range of physical properties for each lithology and serve to illustrate that the different lithologies studied have characteristic physical property ranges. 2.6.2 Physical Properties and Grade Each kimberlite lithology appears to have a characteristic combination of physical properties resulting from variations in primary and secondary geologic processes. Because of these geologic processes, each lithology may also have different diamond contents, which can then be related to physical properties. If strong correlations exist between diamond grade and physical properties because of the effects of geologic processes, tentative high-grade regions of a pipe may be detected from three-dimensional physical property models. Diamond grade does differ slightly between lithologies that have experienced rather different formational processes (Figure 2.15), although significant overlap does exist. Heterolithic and autolithic V K B have very similar diamond contents. Lithic breccia samples tend to have fewer diamonds per given volume than the volcaniclastic kimberlite breccias. Hypabyssal kimberlite is lowest grade, both with respect to number and size of diamonds. 33 000 0.05 0.10 015 0.20 0.25 0.30 Macrocryst: Microcryst Figure 2.15: Plot illustrating diamond grade characteristics of autolithic VKB (black diamond), heterolithic VKB (grey square), lithic breccia (black star), and hypabyssal kimberlite (grey triangles) lithologies, with the number of diamonds per 100 kg on the vertical axis and the ratio of macrocryst-sized stones (> 1 mm) to microcryst-sized stones (< 1 mm) on the horizontal axis. The dashed line emphasizes the inverse relationship between grade indicators. Volcaniclastic samples off of this trend are highlighted by the arrow. A plot of grade indicators and physical properties with depth along the LT508-1 drillhole highlights some interpreted relationships (Figure 2.16). Magnetic susceptibility roughly increases with depth, due to increasing magnetite content within crustal xenoliths that are increasingly common at depth. Susceptibility is inversely related to stones/100 kg within given intervals but directly related to macrocryst:microcryst ratio in some samples. Density appears to be inversely related to susceptibility in the V K B lithologies (above 251 m), and directly related in the lithic breccia. Density is directly related to diamond grade in the V K B lithologies, but inversely related to stones/100 kg in the lithic breccia. Autolithic Volcaniclastic Kimberlite Breccia Heterolithic Volcaniclastic Kimberlite Breccia Lithic Breccia 95 100 105 111 115 120 129 134 139 144 148 172 176 180 190 202 206 210 215 229 233 239 251 256 Depth (m) Figure 2.16: Schematic plot illustrating qualitative relationships between the grade indicators (stones/100 kg and macrocryst: microcryst) and physical properties (magnetic susceptibility and density) with depth. Values of each property have been normalized to a range between 0-1, so as to illustrate the variability of each property with depth. High diamond contents appear to be limited to rocks with a specific combination of magnetic susceptibility and density, such that all samples with more than 150 stones/100 kg (arbitrarily defining high grade) have susceptibilities less than 10x10" SI and densities between 2.44 and 2.51 g/cm3 (Figure 2.17). This combination of susceptibility and density is 100% effective at identifying high-grade samples, but only 60% effective at excluding low-grade samples. These high-grade rocks tend to have low macrocryst:microcryst ratios, suggesting that these rocks tend to have many small stones as well as larger stones. Conversely, rocks with low diamond contents have relatively few small diamonds. Limited data was used to make these observations, therefore they must be considered with caution. A much larger database with more samples of all lithologies and more physical property measurements would be required to define relationships with confidence. 35 25 20 M «? o « 15 5" a 5 o g 10 CO o a> c O) (0 S 5 X • X X X X A X A X • • Stones/ 100 kg • <100 X100-150 • 150-200 A 200-250 • 250-300 • >300 2.35 2.4 2.45 2.5 Density (g/cm3) 2.55 2.6 2.65 Figure 2.17: Physical property characteristics of samples with diamond content indicated by symbol. The black box identifies a range of susceptibility and density characteristic of high-grade samples (arbitrarily defined as > 150 stones/100 kg). 25 20 CO •? o ^15 Q. 0) u « 10 CO u at TO X X X X .-. • * X • X • * X • Macrocryst: Microcryst • <0.05 X 0.05-0.1 • 0.1-0.15 • 0.15-0.2 • >0.2 0 2.35 2.4 2.45 2.5 Density (g/cm3) 2.55 2.6 2.65 Figure 2.18: Macrocryst:microcryst ratio is plotted in susceptibility-density space to illustrate the relationship between diamond size and physical properties. The black box was defined in Figure 2.19. 36 2.6.3 Correlation Analysis Correlations were calculated between a variety of physical properties, diamond grade indicators, and geologic properties to assess whether quantitative relationships can be confidently established for the Anuri kimberlite. Correlation coefficients measure the strength of the connection between two variables, accounting for variance in each variable. They were calculated for a fine-scale data set, consisting of all properties measured on a 1 m scale (Table 2.8), and a coarse-scale data set (Table 2.9), with all physical properties averaged over the crushing intervals for the grade indicators (stones/100 kg and macrocryst:microcrysf ratio). Both data sets were assembled from the LT508-1 drillhole (data can be found in Appendix 1). Comparing correlations for all properties on the two scales may provide insight into whether the observation interval has a significant effect on correlations between physical properties and geological features. 2.6.3.1 Fine-Scale Variations Significant correlations between physical properties, grade data and geologic parameters in the fine-scale data are numerous (Table 2.9 and 2.10). Susceptibility correlates with alteration, crustal xenolith content, and grains larger than 10 cm, indicating that susceptibility is a function of magnetite produced during serpentinization and occurring in large crustal xenoliths. This was also observed during the magnetic phase analysis (Section 2.5.1). Density is inversely correlated with the amount of matrix and fine grains (< 1 cm) and directly related to xenolith frequency and coarse grains (>10 cm). This suggests that the densest rocks have abundant large grains, which are predominantly xenoliths. Density is also directly related to depth, facies, and susceptibility, suggesting that dense crustal xenoliths within the heterolithic VKB and lithic breccia facies contribute significantly to density. Diamond abundance (stones/100 kg) is directly related to autolith and mantle xenocryst content, suggesting that diamonds are sorted together with other kimberlitic and mantle-derived material. Furthermore, diamond abundance is inversely related to crustal xenolith content, because the addition of crustal material dilutes the diamond grade. Diamond content is inversely related to depth and facies, indicating that grades are highest in the autolithic VKB, which is the shallowest lithology, and lowest in the lithic breccia at the base of the drill hole. Macrocryst:microcryst ratio is directly related to depth, crustal xenolith content 37 and facies, suggesting that the rocks rich in crustal xenoliths (lithic breccia and heterolithic VKB) have higher proportions of large diamonds to small diamonds. Perhaps this is because they have fewer diamonds overall and fewer small diamonds. 2.6.3.2 Coarse-Scale Variations Significant correlations between the physical properties, grade indicators and the geologic properties are much less common in the coarse-scale data than in the fine-scale data. Susceptibility correlates solely with stones/100 kg, in a negative sense. Thus, susceptibility is inversely related to diamond grade on the scale that the diamond indicators were measured. Density is directly related to bedding, as an indicator of sedimentation, and inversely related to veining, as a measure of alteration. Therefore, density appears to be a function of sedimentary processes that cause sorting of diamonds with dense and magnetic oxide minerals. Conversely, density is also appears to be decreased by alteration, including serpentinization and weathering. Although relationships between physical properties, grade and geologic properties are different in coarse-scale data than fine-scale data, they are nonetheless significant and indicative of geologic processes. Effects of Scaling on Correlations Obviously, the observation scale of physical properties, grade indicators and geologic properties is crucial for determining whether and how physical properties will relate to mineralogy and grade due to the effects of primary and secondary geologic processes. Several correlations were significant in the fine-scale data, many of which are not present in the coarse-scale data. Although the coarse-scale data produced less significant relationships, it is typically at this scale that geological and geophysical data are collected in the field or from core. Furthermore, geophysical inversions produce coarse-scale data. Correlations in coarse-scale data are thus more realistic for the exploration processes. 38 Table 2.9: Matrix of correlation coefficients between the various grade, geologic features and physical properties measured on a fine-scale9. j. Bed. Sort. Matrix <2mm <1cm 2-5 cm 5-10 cm >10 cm * e n o Autolith Crustal Mantle Alt. Freq. Variables Depth (m) Sus Density Stones /"lOOka Mac :Mic Facies Depth (m) Sus 0.234 Density 0.258 0.189 Stones /100kg -0.337 -0.003 0.105 Mac :Mic 0.313 -0.094 -0.219 -0.363 Facies 0.830 0.159 0.213 -0.316 0.192 Frag /Bedded -0.184 0.100 -0.090 0.206 -0.094 -0.248 Bedding 0.049 -0.081 -0.092 0.190 0.104 -0.108 Sorting -0.362 -0.164 -0.236 -0.008 -0.023 -0.204 Matrix -0.029 -0.091 -0.247 0.008 0.121 0.077 <2mm 0.296 -0.061 -0.405 -0.160 0.256 0.261 <1cm -0.416 -0.180 -0.175 0.149 0.005 -0.276 2 to 5 cm -0.426 -0.227 0.133 0.059 -0.163 -0.372 5 to 10 cm 0.104 -0.015 0.180 -0.002 -0.124 0.123 >10 cm 0.294 0.404 0.435 0.001 -0.111 0.140 Xeno Freq 0.423 0.182 0.245 -0.140 0.073 0.218 Autoliths -0.560 -0.181 0.035 0.198 -0.175 -0.430 Crustal 0.739 0.222 -0.018 -0.227 0.249 0.603 Mantle -0.693 -0.182 0.000 0.200 -0.245 -0.586 Alteration 0.734 0.229 0.072 -0.148 0.356 0.635 Velnlng 0^.247 0.060 0.029 0.036 -0.154 -0.241 0.482 0.266 0.417 0.336 -0.019 -0.073 -0.111 -0.419 -0.540 0.118 -0.517 -0.623 -0.217 -0.211 0.130 0.290 0.424 -0.257 0.138 0.416 -0.353 -0.584 -0.103 0.263 0.108 0.239 -0.791 0.272 0.473 -0.912 0.337 -0.434 0.618 -0.600 0.073 0.207 -0.242 0.212 9 Significant correlations are shown in bold. Facies represents the lithologies (autolithic VKB, heterolithic VKB, lithic breccia); fragmental (frag) represents the degree of fragmentation of the core; bedding (bed.) and sorting (sort.) were measured on relative scales (poor to good); < 2 mm to > 10 cm represent the proportions of material that falls into each grain size; xenolith frequency was quantified as proportion (%) of core that consists of autoliths, crustal and mantle xenoliths (each quantified as percent of xenoliths that are each type); alteration and veining were quantified relatively (fresh to highly altered, no veins to several). Table 2.10: Correlation coefficients between the various grade, geologic and physical properties measured on a coarse-scale 1 0 . Variables Depth (m) Sus Density Stones /100kg Mac: Mic Facies Frag. Bed. Sort. Matrix <2 mm <1 cm 2-5 cm 5-10 cm >10 cm Xeno Frea Autolith Crustal Depth (m) Sus 0.422 Density 0.073 0.045 Stones /100kg -0.321 -0.471 -0.028 Mac :Mic 0.183 0.243 0.131 -0.336 Facies 0.797 0.334 0.029 -0.222 0.083 Frag /Bedded -0.440 0.112 -0.037 0.195 -0.166 -0.467 Bedding 0.511 0.247 0.512 0.038 0.061 0.355 -0.085 Sorting 0.586 0.148 6.140 0.028 0.147 0.309 -0.173 0.277 Matrix 0.237 0.201 -0.184 0.282 -0.263 0.172 0.001 0.147 -0.105 <2mm 0.405 -0.001 -0.063 -0.183 0.371 0.238 -0.392 -0.233 0.577 -0.121 <1cm 0.329 0.029 0.342 0.230 -0.087 0.381 0.137 0.321 0.630 -0.218 0.079 2-5 cm •0.524 -0.144 -0.169 -0.047 -0.019 -0.528 0.148 -0.113 -0.767 0.043 -0.621 -0.732 5-10 cm -0.270 0.076 0.060 0.062 -0.509 -0.107 0.232 0.218 -0.612 0.275 -0.731 -0.298 0.459 >10 cm 0.315 0.126 0.092 -0.298 0.027 0.570 -0.280 -0.166 -0.010 0.064 0.319 0.109 -0.467 0.042 Xeno Freq 0.071 0.083 0.003 -0.119 -0.225 0.312 -0.039 0.285 -0.087 -0.154 -0.567 0.175 0.075 0.483 0.214 Autoliths -0.459 -0.222 0.322 -0.107 -0.114 -0.138 0.086 -0.036 -0.505 -0.602 -0.463 0.015 0.293 0.435 0.101 0.410 Crustal 0.646 0.279 -0.123 0.063 0.166 0.365 -0.117 0.357 0.846 0.117 0.408 0.552 -0.611 -0.584 -0.195 -0.099 -0.677 Mantle -0.515 -0.213 -0.089 -0.013 -0.134 -0.352 0.087 -0.481 -0.754 0.284 -0.181 -0.730 0.565 0.445 0.237 -0.160 0.169 -0.838 Alteration -0.424 0.061 -0.211 0.016 -0.364 -0.275 0.276 0.008 -0.456 0.058 -0.831 -0.242 0.595 0.541 -0.365 0.614 0.322 -0.275 Veining -0.284 -0.138 -0.606 0.153 0.203 -0.176 0.085 -0.605 -0.055 0.068 0.350 -0.239 -0.030 -0.391 0.053 -0.304 -0.394 0.067 1 0 Significant correlations are shown in bold. Properties as described for Table 2.8. o 2.6.4 Principal Component Analysis Principal Component Analysis was performed to detect structure in relationships between different physical, grade and geologic properties, by extracting components that may represent different geologic processes or features. Principal Component Analysis revealed that 51% of variability in the fine-scale data and 58% of variability in the coarse-scale data could be represented by three components, determined to be significant using the scree test (Cattell, 1966) (Figure 2.19, Table 2.11). The first significant component of the fine-scale data (Table 2.12) correlates most significantly with depth, facies, crustal xenoliths, and alteration in a positive sense. This suggests that component one represents lithologies, which progress from autolithic VKB to heterolithic VKB to lithic breccia with depth. The deeper lithologies contain more crustal xenoliths and tend to appear more altered with depth. Component one also correlates in a negative sense with autoliths and mantle xenoliths, reaffirming that these components decrease in abundance at depth. Component two correlates positively with fine-grained material (matrix and grains less than 2 mm in size) and negatively with xenoliths and coarse-grained material (grains over 2 cm in size). Therefore, this component appears to represent sorting, measured as grain size homogeneity, and the amount of kimberlitic groundmass. Component two correlates inversely with density, suggesting that density is a function of coarse-grained material within the kimberlite. Component three correlates in a weak positive sense with magnetic susceptibility, stones/100 kg, and very coarse grains (> 10 cm) and inversely with macrocryst:microcryst ratio. It may indicate sorting of large magnetic grains together with diamonds. Principal Component Analysis of the coarse-scale data (Table 2.12) yielded similar components. Component one correlates similarly with all the same variables as in the fine-scale data. Additionally, it correlates with sorting, fine grain sizes and negatively with coarse grain sizes. Component two correlates directly with density, xenolith frequency and coarse grains and inversely with fine grains, unlike in the fine-scale data. The third component derived from the coarse-scale data correlates inversely with stones/100 kg, unlike in the fine-scale data, and directly with coarse grains (>10 cm). The first component appears to represent lithological characteristics in both the fine and coarse-scale data. Conversely, components two and three appear to represent sorting, though in inverse senses for the fine and coarse data. This is 41 potentially because there is too little data from which to draw definite conclusions and highlight significant trends. Additional physical property, grade, and geologic data for different lithologies in both lobes of the kimberlite pipe could potentially allow for quantitative relationships to be established, as statistically significant correlations do appear to exist. 5 g 3 CO Lu F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 Figure 2.19: "Scree" plot for the Principal Component Analysis. The scree test identifies significant variables as those with eigenvalues that fall within the smooth decrease before the eigenvalues level off (at about F3 in this case) (Cattell, 1966). Table 2.11: Tables indicating the eigenvalues, variability explained by each component and the cumulative variability of the data explained by the three components determined to be significant using the scree test, for fine-scale data (left) and coarse-scale data (right). Fine-scale data Coarse-scale data F1 F2 F3 F1 F2 F3 Eigenvalue 5.669 Variability (%) 26.996 Cumulative % 26.996 3.535 16.831 43.827 1.661 7.909 51.736 Eigenvalue 6.189 Variability (%) 29.472 Cumulative % 29.472 3.525 16.786 46.258 2.470 11.761 58.019 42 Table 2.12: Factor loadings for the significant components (FI, F2, F3) created by the Principal Component Analysis of both the fine (left) and coarse (right) scale data. Fine-scale data Coarse-scale data fi F2 F3 FI F2 F3 Depth (m) 0.91 -0.08 -0.16 Depth (m) 0.79 -0.30 0.30 Susceptibility 0.31 -0.25 0.48 Susceptibility 0.27 -0.27 0.25 Density 0.12 -0.56 0.14 Density 0.12 -0.47 0.08 Stones/100kg -0.33 -0.10 0.50 Stones/100kg -0.11 0.09 -0.64 Macrocryst: Macrocryst: Microcryst 0.34 0.29 -0.49 Microcryst 0.32 0.26 0.25 Facies 0.77 0.02 -0.20 Facies 0.60 -0.38 0.47 Fragmental/ Fragmental/ Bedded -0.13 -0.14 0.44 Bedded -0.34 -0.02 -0.49 Bedding -0.01 0.14 -0.03 Bedding 0.30 -0.73 -0.13 Sorting -0.38 0.65 0.05 Sorting 0.88 -0.05 -0.30 Matrix 0.04 0.77 0.25 Matrix -0.01 0.05 0.01 <2mm 0.37 0.74 -0.01 <2mm 0.71 0.58 0.24 <1cm -0.50 0.27 -0.20 <1cm 0.59 -0.42 -0.37 2 to 5 cm -0.57 -0.44 -0.40 2-5 cm -0.83 0.05 0.00 5 to 10 cm 0.01 -0.56 -0.26 5-10 cm -0.68 -0.52 0.15 >10 cm 0.39 -0.62 0.41 >10 cm 0.23 -0.04 0.76 Xenolith Xenolith Frequency 0.39 -0.63 -0.26 Frequency -0.19 -0.71 0.12 Autoliths -0.71 -0.20 -0.18 Autoliths -0.54 -0.41 0.20 Crustal 0.90 0.16 0.13 Crustal 0.84 -0.05 -0.41 Mantle -0.83 -0.10 -0.06 Mantle -0.71 0.38 0.43 Alteration 0.78 -0.05 -0.15 Alteration -0.66 -0.40 -0.24 Veining -0.32 -0.14 0.11 Veining 0.00 0.79 -0.07 2.7 Discussion The results presented in this chapter suggest that both qualitative and quantitative relationships can be established between physical properties, lithology and diamond grade due to geologic processes that formed the Anuri kimberlite. These relationships could allow for interpretation of physical property models produced by inversions with respect to mineralogy. In order to establish relationships between mineralogy, magnetic susceptibility and density, the compositions and origins of dense and magnetic minerals occurring within the different kimberlite lithologies were determined. Subsequently, correlations between dense magnetic phases, resulting physical properties, lithology, and diamond grade were determined and are discussed in the context of primary and secondary processes. Potential for ore estimation based on susceptibility and density is assessed based on relationships presented in Section 2.6.2. 43 2.7.1 Characterization of Dense and Magnetic Minerals Physical properties are primarily a function of dense and magnetic mineral phases occurring within the kimberlite, both at the time of its formation and produced post-emplacement by alteration processes. In general, magnetic phases occurring in the Anuri are ilmenite, spinel-series chromite and magnetite, and end-member magnetite. Magnetite is the most abundant magnetic phase in the lithic breccia, and its abundance appears to control susceptibility in this lithology. In contrast, the predominant magnetic mineral within the volcaniclastic kimberlite breccia lithologies is ilmenite. Magnetite is relatively rare in the VKB lithologies, likely because it is too fine-grained to occur within the medium size fraction used for the analysis. Despite the relative abundance of ilmenite and chromite in the volcaniclastic kimberlite breccias, magnetite likely controls the susceptibility of these kimberlitic rocks because of its susceptibility can be orders of magnitude greater than that of ilmenite or chromite (Figure 2.2). Compositional data and modes of occurrence determined from petrographical work were used to identify the origins of the dense and magnetic phases. Ilmenite and chromite both tend to occur as macrocrysts within the kimberlite. These phases would be concentrated with diamonds because they underwent similar entrainment, disaggregation and eruption processes within the kimberlite. Magnetite predominantly occurs in crustal xenoliths, which are most abundant within the lithic breccia and in deeper portion of the heterolithic VKB. Addition of crustal xenoliths to the volcaniclastic pile causes dilution of the diamond grade. Therefore, magnetite, and consequently magnetic susceptibility, should be inversely related to diamond grade. 2.7.2 Linking Rock Type and Physical Properties through Primary and Secondary Physical Properties Primary and secondary geological processes that formed the various kimberlitic units have created different physical property and grade characteristics within and between geological units (Figure 2.20). In the Anuri kimberlite, lithic breccia is characterized by high density, due to the abundance of crustal xenoliths whose silicate components are denser than the alteration products that dominate the kimberlite (clay and serpentine), and moderate susceptibilities, due to magnetite occurring within crustal xenoliths. The lithic breccia is relatively low grade. Significant addition of magnetite-bearing crustal xenoliths to kimberlite comprising the lithic breccia has caused dilution of the diamond grade. Hence, there is an inverse relationship between physical properties, including both susceptibility and density, and grade for this unit. 44 Overall low densities of heterolithic volcaniclastic kimberlite breccia in the Anuri pipe are likely due to replacement of primary ferromagnesian minerals with serpentine and clay minerals, and low concentrations of mantle-derived material. HVKB has moderately high susceptibility that could result from magnetite produced during serpentinization or from magnetite within crustal xenoliths. Diamond grade within the heterolithic volcaniclastic kimberlite breccia is inversely related to susceptibility but directly related to density. The direct relationship between diamond grade and density likely results from concentrations of mantle xenocrysts, including diamonds, in specific HVKB beds due to sorting. These diamondiferous mantle xenocryst-rich beds would contain fewer magnetite-bearing crustal xenoliths and less kimberlitic material susceptible to serpentinization, perhaps causing the inverse relationship between diamond grade and susceptibility. Heterolithic VKB in the eastern lobe has fewer diamonds than heterolithic VKB of the western lobe, though macrocryst:microcryst ratios are higher in the eastern lobe than in the western lobe. Physical properties of the heterolithic VKB in the western and eastern lobes are comparable, so low grade HVKB cannot be differentiated from high grade HVKB using physical properties. Autolithic volcaniclastic kimberlite breccia in the Anuri kimberlite is characterized by moderate density and low susceptibility. Abundant mantle xenocrysts cause the AVKB to be moderately dense. Low susceptibility likely results from the relative lack of magnetite, determined by the magnetic oxide mineral analysis. Furthermore, AVKB has the highest diamond grade, supporting the conclusion that susceptibility is inversely related to diamond grade. Density may be loosely related to grade within this unit due to common sorting of heavy mineral grains during pyroclastic eruption and resedimentation, as was also observed for the HVKB. Although fine-grained volcaniclastic kimberlite breccia (FVKB) was not studied directly, database measurements of susceptibility and grade indicate that it has a wide range of susceptibilities, spanning that of the heterolithic VKB. Fine-grained kimberlite is low grade, as diamonds were likely not sorted together with fine-grained material. The range of susceptibilities typical of the FVKB mean that identification of this low-grade unit using magnetic susceptibility is not feasible. Density data was unavailable. Hypabyssal kimberlite was also not available for first-hand study, but physical property data provided by Kennecott Exploration Inc. indicates that it generally has high susceptibilities and moderate densities. Hypabyssal kimberlite within the Anuri kimberlite is lower grade than the volcaniclastic kimberlite breccias. 45 PJ o CO Heterolithic VKB Granite Hypabyssal Kimberlite Lithic Breccia Autolithic VKB Mud-rich VKB \ Serpentinization I Density (g/cm3) Figure 2.20: Schematic diagram showing the effects of serpentinization (black arrows) on physical properties of the various kimberlite lithologies that occur within Anuri kimberlite and the host granite (black). The grade of the kimberlitic lithologies is indicated by the shade of grey (e.g. black = high grade, light grey = low grade). In summary, kimberlite lithologies within the Anuri kimberlite can be characterized with respect to physical properties and grade content, which represent the interplay of eruptive processes and secondary alteration (Figure 2.21). Eruptive processes include deposition of kimberlitic material into the pipe by airfall and resedimentation, resulting in sorting of mantle-derived minerals with diamonds, and incorporation of crustal xenoliths during eruption and pipe-wall collapse. Consequently, density and susceptibility should be directly related to diamond grade in the crustal xenolith-poor V K B . In the lithic breccia, however, density and susceptibility should be inversely related to diamond grade. Secondary processes include serpentinization, which produced magnetite, and weathering. Neither secondary process affected diamond content but did cause susceptibility to increase and density to decrease, thus changing the physical property - mineralogy relationships. 4 6 A) Magnetic Susceptibility B) Density Figure 2.21: Schematic diagrams of a simplified kimberlite pipe with crater facies volcaniclastic kimberlite overlying hypabyssal facies kimberlite, hosted by granite. White stars schematically signify that diamonds are concentrated at the base of normally graded units throughout the volcaniclastic kimberlite pile. Shades of grey indicates relative susceptibilities and densities of the various lithologies (black for high, white for low). 2.7.3 Estimation of Diamond Grade from Physical Properties As clear qualitative relationships exist between physical properties and diamond grade for each kimberlite lithology, quantitative relationships could be developed for estimating diamond grade or identifying regions of high diamond potential within kimberlite pipes from three-dimensional physical property models produced by inversions. Determining what constitutes "high-grade" is more difficult for diamond deposits than for base metal deposits, for example, since diamond value relies on so many factors (e.g. colour, clarity). Diamond abundance (stones/100 kg) and diamond size ratio (macrocryst:microcryst) data were available for this study, and "high-grade" samples were arbitrarily defined as those with high diamond abundances (>150 stones/100 kg). Physical properties can be directly related to diamond abundance, as high-grade samples characteristically have susceptibilities less than 10 x 10"3 SI and densities of 2.42 -2.51 g/cm3 (Figure 2.17). High-grade samples appear to have lower microcryst: macrocryst ratios, but this is because there are more diamonds within these rocks and thus more small diamonds as well as large diamonds (Figure 2.18). The range of physical properties conducive to higher diamond grades appears to be similar to the physical properties characteristic of the AVKB lithology, which has abundant mantle xenocrysts likely sorted together with diamond. Therefore, a clear relationship exists between physical properties, diamond grade and rock type, as a result of primary and secondary geologic processes that have formed the Anuri kimberlite. A larger dataset would allow for these relationships to be established quantitatively with statistical confidence. 2.8 Conclusions The aim of this study was to develop an understanding of minerals contributing to physical properties in kimberlite and how these phases relate to the presence of diamonds through primary and secondary geologic processes. Consequently, quantitative relationships may be defined between physical properties, rock type, and grade. Magnetic phases that occur within kimberlite are predominantly ilmenite, chromite and magnetite. Ilmenite and chromite typically occur as macrocrysts, and are most abundant within the volcaniclastic kimberlite breccias. Magnetite predominantly occurs within crustal xenoliths and as fine grains produced by serpentinization. Magnetite's susceptibility is typically orders of magnitude greater than that of any other magnetic oxide mineral, thus the abundance of 48 magnetite is likely the primary control on susceptibility. Relative proportions of magnetic minerals within the various kimberlitic lithologies could be determined more accurately by using a large number of samples from all kimberlite lithologies. Kimberlite lithologies within the Anuri kimberlite have distinct combinations of susceptibility and density due to primary and secondary processes that were active in each rock type (Figure 2.2 i). Concentrations of mantle xenocrysts (ilmenite and chromite) formed by resedimentation processes during eruption cause the autolithic volcaniclastic kimberlite breccia to have high densities but low susceptibilities. Conversely, concentrations of magnetite-bearing crustal xenoliths formed during eruption and resedimentation of the pipe causes the lithic breccia to have high densities and susceptibilities. Moderate susceptibilities and low densities of the heterolithic VKB appear to be caused by the presence of crustal xenoliths and serpentinization. Thus, geologic processes, including primary sedimentation and secondary serpentinization, are manifested in the various rock types and have greatly affected the physical properties of the kimberlite. Physical property - grade relationships could not be quantitatively established with statistical confidence, due to the limited amount of data, but were qualitatively assessed. Diamond abundance tends to be directly related to density, because sorting during pyroclastic fall and resedimentation has concentrated diamonds with dense mantle-derived minerals. Diamond abundance is inversely related to susceptibility, due to dilution of diamond grade with the addition of crustal xenoliths. Therefore, a combination of physical properties can tentatively be used to highlight high-grade regions within the kimberlite pipe. A significantly larger database is needed, however, to make statistically confident relationships now that the geologic relationships between physical properties and mineralogy are understood. Relationships between physical properties, lithology, and grade established in this study can likely be extended to many of the Slave craton kimberlite pipes, especially within the Lac de Gras field, because of similarities in host rocks and geological processes (Kolebaba, 2003). This could greatly assist the kimberlite exploration process in northern Canada, by using geophysical data to estimate rock type and diamond potential. 49 Chapter 3: Quantifying the Effects of Primary and Secondary Geologic Processes on Physical Properties in the Magmatic Sulfide Environment 3.1 Introduction Magmatic sulfide deposits are highly desirable due to their diversity of metals (Ni, Cu, Co, PGE, Au) and economic value (Dowsett, 1970); about 60% of the world's nickel is produced from Fe-Ni-Cu sulfide minerals found in association with mafic or ultramafic intrusions or flows (Barnes and Lightfoot, 2005). Despite these attractions, their rarity and the small size of the massive sulfides makes them a challenging exploration target (Thompson, 2004; Peck, 2005). Consequently, new exploration techniques are required to improve success rates. In more recent years, mineral exploration has used a combination of geological, geochemical and geophysical techniques to focus on deposits buried beneath extensive weathered or transported cover. Geological methods entail selecting regional targets based on a geological understanding of genetic requirements for economic magmatic sulfide deposits, including geologic terrane, country rocks as a source of sulfur, and magmatic affinities (Table 3. i) (Lesher, 2004; Thompson, 2004; Lesher, 2005). Geochemical techniques focus in on prospective areas by recognizing nickel and pathfinder element (Pt, Ir) dispersion patterns (Arndt et al., 2005), or contamination and sulfide segregation signatures in comagmatic volcanic rocks or host sedimentary rocks (Thompson, 2004). Geophysical techniques, commonly magnetic and gravity methods (Foose et al., 1995), are valuable tools for locating the sulfide ores and mafic-ultramafic host rocks of magmatic sulfide deposits (Dowsett, 1967; West, 1992; McCall et al., 1995; Gunn and Dentith, 1997; Lesher, 2004). 50 Table 3.1: Characteristics of select economic stratiform Ni-Cu-(PGE) sulfides (from Naldrett, 2004). Deposit Kabanga Noril'sk Jinchuan Pechenga Thompson Mt Keith Voisey's Bay Kambalda Perseverance Raglan Resource (Mt) 26.4 1309.3 515 339 150.3 478 136.7 67 52 24.7 Ni wt% 2.6 1.77 1.06 1.18 2.32 0.6 1.59 2.9 1.9 2.72 Cu wt% 0.27 3.57 0.75 0.63 0.16 0.01 0.85 0.21 0.1 0.7 Co wt% 0.16 0.061 0.019 0.045 0.046 0.014 0.09 0.207 0.054 Pt(g/t) 1.84 0.13 0.12 0.1 0.07 0.3 0.82 Pd (g/t) 7.31 0.1 0.17 0.54 0.1 0.42 2.27 Age Middle Phanerozoic Early Early Early Proterozoic Late Archean Middle Late Archean Late Archean Early Proterozoic Proterozoic Proterozoic Proterozoic Proterozoic Tectonic Environment Related Magmatism Lithospheric rifting Misc. Picrite- Flood Basalt Tholeiite Host Rocks Metapelite Sedimentary Rift Misc. Picrite- Ferropicrite Tholeiite Marbles and gneisses Rifting on downdrop margin of Superior plate Komatiite Meta-sedimentary (black shales) Within fault-bounded rift zone greenstone belt Komatiite Graphitic sulfide facies iron formation or pelitic schists Spinifex-textured komatiite and concordant olivine adcumulate Anorthosite-Granite Troctolite Orthogneiss Within fault-bounded Within fault-rift zone greenstone bounded rift zone belt greenstone belt Komatiite Komatiite Ultramafic (peridotite) unit overtop of pillowed basalts and overlain by komatiitic basalts Mesocumulate dunitic flows in contact with and deformed by adcumulate dunite Continental rift Komatiite Conformably underlain by metapelites, overlain by basalts Intrusive sequence Type of sulfides Peridotite to Picritic to Dunite to Gabbro-Gabbro olivine gabbro- olivine wehrlite dolerite pyroxenite Metamorphosed peridotite Disseminated Disseminated to massive sulfide (pyrrhotite with pn, cpy) Dominant ore Stratiform occurrence Disseminate sulfide to d to net massive sulfide textured (po with pn, (PGE-rich) cpy, cubanite sulfides (po, and mgt) with pn, cpy, halo of Cu-ore pyrite) Stratiform Stratiform Massive, breccia, disseminated pyrrhotite, pentlandite, chalcopyrite with minor pyrite, magnetite Ni-poor sedimentary sulfides and Ni-enriched sedimentary sulfides (po, cpy, py), Ni-bearing magmatic sulfides (po, pn, cpy) N/A Olivine gabbro to troctolite, with ore hosted by magmatic breccia Disseminated Disseminated, sulfides blotchy and N/A N/A Layers in meta-sediment upgraded during serpent-inization (liberation of Ni in olivine) massive sulfide (po, pn, cpy, cubanite, mgt) Finely Feeder disseminated conduits Contact ore at base of lowermost unit, hanging wall ore (at base of overlying units or as zones of blebby sulfide), offset ore as po, pn, pyrite, oxides, cpy Stratiform Massive sulfide horizon at base of ultramafic flow, disseminated sulfides within adcumulate dunite Peridotite-pyroxenite and gabbro Massive to net textured ore within ultramafic lavas and ultramafic rocks of the basaltic/ magnesian basaltic Finely disseminated Stratiform channelized sheet flows Magnetic and gravity data can be inverted to three-dimensional magnetic susceptibility and density models using new inversion algorithms. These models can be meaningfully interpreted with respect to geological features, given a good understanding of how susceptibility and density relate to mineralogy and rock type. Physical properties of rocks associated with magmatic sulfide occurrences are relatively straightforward, due to the limited number of rock types that typically occur in this deposit environment. Massive sulfide ore bodies occur in well-defined zones as footwall embayments and veins, and as disseminated sulfides (Foose et al., 1995; Naldrett, 1999; Naldrett, 2004, Lesher, 2005). Massive sulfide bodies typically display distinct geophysical signatures due to concentrations of dense and magnetic sulfide and oxide minerals (Harman, 2004; Lesher, 2004). Ore occurs in association with or hosted by mafic and ultramafic volcanic flows (Figure 3.1 A) and intrusions (Figure 3.IB) comprising dunite, peridotite, norite and gabbro (Table 3.1). These mafic-ultramafic rocks all have characteristic physical properties based on their mineral assemblages. However, these rocks are commonly serpentinized. Serpentinization is the process by which primary olivine and pyroxene minerals are hydrated to form serpentine-group minerals, brucite and magnetite (Coleman, 1971; Moody, 1976). Mineralogical changes resulting from serpentinization drastically change the physical properties of ultramafic rocks and consequently the contrast between ultramafic rocks and the massive sulfide ore they host (Measday, 2004). In order to meaningfully interpret physical property models with respect to rock type or ore content in a variety of magmatic sulfide systems, a better understanding is required of how geological processes involved in magmatic sulfide deposits affect physical properties of mafic-ultramafic and massive sulfide rocks. Figure 3.1: Simplified cross-sections of an extrusive (A) and intrusive (B) magmatic sulfide deposit. A) Diagrammatic cross-section illustrating the location of sulfide mineralization and the relationship between channel and sheet flow facies (modified after Sipa Resources, 2006). B) ESE-WNW section through the Eastern Deeps at Voisey's Bay (Naldrett, 1999). 52 Despite differences in morphology and textures between extrusive and intrusive magmatic sulfide deposits (Table 3.1; Figure 3.1), physical property characteristics of rock types in both intrusive and extrusive bodies are similar and are expected to be affected by alteration in a comparable manner. As such, in this study only an intrusive deposit was examined, and the findings can be applied to extrusive magmatic sulfide deposits. The Kabanga Ni-Cu deposit, a joint venture project between Barrick Gold Corporation and Falconbridge Limited, is an intrusive magmatic sulfide deposit located in northwestern Tanzania, Africa (Figure 3.2). Exploration to date has defined inferred resources of 26.4 million tonnes grading 2.6% N i (Falconbridge, 2005). Kabanga was chosen for this study because it has a wide range of rock types in a relatively coherent sequence, with distinct physical properties. Furthermore, several ore bodies occurring in close proximity have experienced slightly different emplacement and alteration histories despite being within the same magmatic system. Lastly, rock samples and an extensive drillhole database are available. / ^ Overturned Bedding / J • Drill hole location Figure 3.2: Location map of the Kabanga deposit in northwestern Tanzania, near to the Burundi border. The inset map shows the location of the Kabanga deposits, North and Main, with respect to the main geological units and geophysical anomalies. (Modified after Livesey and Murgatroyd, 2003, and Evans et al., 2000). 53 3.1.1 Objectives Susceptibilities and densities of rocks are averages of the physical properties of the mineral constituents. Hence, physical properties can be quantitatively linked to mineralogy. Because physical properties of magmatic sulfide deposits are relatively straightforward, there is potential for ore mineral estimation from susceptibility and density in these deposits, once the effects of primary and secondary geologic processes are understood. The principle objective of this study is to gain an understanding of how physical properties relate to mineralogy because of the effects of primary and secondary geologic processes. This was accomplished by the following tactical objectives: 1) Identify dense and magnetic phases occurring within rock type characteristically associated with magmatic sulfide deposits; 2) Determine the origin of these minerals through petrographical analysis; 3) Characterize physical properties of the various lithologies at Kabanga and explain differences between and within rock types using variations in mineralogy resulting from differences in primary and secondary geologic processes; 4) Attempt to quantify relationships between mineralogy and physical properties using graphical and statistical techniques. 5) Verify the accuracy of the Mineral Prediction Filter (Williams and Dipple, 2005) by comparing predicted ore mineralogy to observed mineral abundances. Mineral abundances were quantified by visual estimates, which can be associated with large errors (a few percent). Diagrams of modal abundance were used to maintain consistency between model abundance estimates. 3.2 Geophysical Characteristics of Magmatic Sulfide Deposits Physical properties, and thus geophysical expressions, of magmatic sulfide mineralization and ultramafic host rocks are primarily a function of mineralogy (Table 3.2, Figure 3.3). In turn, mineralogy is controlled by magma composition; metal content of the sulfide melt that segregates upon sulfide saturation; position within the intrusion chamber; and degree of alteration (serpentinization and weathering) of both mineralized and mafic-ultramafic rocks (Naldrett, 2004; Lesher, 2005). 54 Table 3.2: Comparison of magnetic susceptibility and density of minerals common in mafic-ultramafic intrusions and associated sulfide deposits 1 3 . Mineral Magnetic Susceptibility (10 SI) Density (g/cm ) Amphibole 0.63-5.00(1) 2.50-2.90 (6) Chlorite 2.42 (6) - 3.30 (6) Clinopyroxene (CPX) 0.25-4.80(1) 3.10-3.63 (6) Olivine -0.013-5.5 (unknown) 3.20-4.39 (6) Orthopyroxene (OPX) 0.380-5.000(1) 3.10 (6)-3.59 (4) Phlogopite 0.200 -0.300(5). 2.70 - 2.90 (6) Plagioclase 2.61 - 2.76 (6) Quartz -0.017 (4)-(-0.01) (2) 2.50 - 2.70 (2) Serpentine 3-17(2) 2.50-2.65 (6) Talc 2.70 - 2.80 (6) Chalcocite 5.50 - 5.80 (6) Chalcopyrite 0.023-0.400(2) 4.10-4.30 (6) Ilmenite 1.9-4000 (3) 4.30-5.00 (6) Magnetite 70 (3)-25000(1) 4.90 - 5.20 (6) Pentlandite 4.6 - 5.0 (6) Pyrite 0.035 - 5.00 (3) 4.90 - 5.20 (6) Pyrrhotite 1.68-3390(4) 4.50 -4.80 (4) Rutile 4.18-4.30 (2) Spinel 0.0505-0.0178 (5) 3.57 (7) - 4.00 (6) Physical properties of minerals Schon, 2004 and Dortman, 1976; (6) WebMineral. within the Kabanga deposits should fall within these ranges. Compiled from: (1) (2) Telford et al., 1990; (3) Parasnis, 1979; (4) Hunt et al., 1995; (5) Clark, 1997; 100000 10000 c 1000 CO Q. CP u w 100 10 CO o <u c (0 0.1 0.01 Serpentine Monoclinic Olivine Amphibole Pyroxene Pyrrhotite Magnetite Hexagonal Pyrrhotite • Chalcopyrite 2.5 3.5 4 Density (g/cm3) 4.5 5.5 Figure 3.3: Comparison of density and susceptibility of main mineral constituents of magmatic sulfide deposits (ranges identified by black box). Compiled from: Schon, 2004; Dortman, 1976; Telford et al., 1990; Parasnis, 1979; Hunt et al., 1995; Clark, 1997; WebMineral. 55 3.2.1 Magnetism Magnetism within magmatic sulfide deposits results from the presence of magnetic minerals, predominantly magnetite and monoclinic pyrrhotite (Dowsett, 1970) (Table 3.2, Figure 3.3). Pyrrhotite, the monoclinic form of which is magnetic, is the dominant constituent of the massive and disseminated sulfide. Magnetite is predominantly a secondary mineral produced by serpentinization of ferromagnesian minerals in mafic-ultramafic rocks. Consequently, airborne magnetic surveys typically identify massive sulfide and associated ultramafic intrusions (Dowsett, 1967; McCall et al., 1995; Gunn and Dentith, 1997; Lesher, 2004), though the associated anomalies may be either magnetic highs or lows, due to remanence (Clark, 1997). 3.2.2 Gravity Development of airborne gravity techniques has led to gravity surveys becoming increasingly popular in the exploration community (Harman, 2004). Moreover, gravity anomalies are relatively simple to interpret, once the data has been properly corrected for elevation, topography, the Earth's nonspherical shape, and tidal effects (West, 1992). The density of rocks typically occurring in magmatic sulfide complexes is primarily a function of the sulfide and ferromagnesian mineral content. Unaltered ultramafic rocks tend to be dense, because they contain high proportions of ferromagnesian minerals. Therefore, fresh ultramafic complexes tend to be associated with positive gravity anomalies (West, 1992; Foose etal., 1995). However, ultramafic rocks are commonly serpentinized. Pervasive serpentinization may reduce the density of the ultramafic rocks below that of the country rocks, causing ultramafic rocks to be associated with negative gravity anomalies. Consequently, serpentinization may enhance the density contrast between sulfide mineralization and the ultramafic complex (Measday, 2004). 3.3 Geology of the Kabanga Deposits 3.3.1 Regional Geology The Kabanga magmatic sulfide deposits occur within the East African Nickel Belt, which is defined as an alignment of ultramafic intrusions along the eastern margin of the Mesoproterozoic (1330-1260 Ma) Kibaran Orogenic belt of East-Central Africa (Wolfgram and Golden, 2001). This belt has been divided into two domains separated by a boundary zone up to 35 km wide, 56 consisting of thrust faults and folds (Deblonde and Tack, 1999) and plutons aligned subparallel to the northeast-southwest trend of the belt (Evans et al., 2000). The Western Internal Domain is characterized by intense deformation, high-temperature metamorphism and abundant Kibaran peraluminous, anatectic crustal granitic intrusions. The Eastern External Domain marginal facies comprises multiply deformed, steeply westward-dipping pelitic and quartzitic metasediments of the Karagwe-Ankolean system, dated at 1370 - 2050 Ma (Wolfgram and Golden, 2001). Sedimentary rocks of the Eastern External Domain experienced low-to-medium grade metamorphism and isoclinical folding during the Kibaran Orogeny at 1370 - 1310 Ma (Evans et al., 2000). Contemporaneous pipe- and sill-like mafic-ultramafic bodies (Figure 3.2; Figure 3.4), which host the Ni-Cu-Co deposits, were emplaced into the Eastern External Domain, due to extensional tectonics and rifting followed by late stage folding and thrust faulting (Evans et al., 1999; Wolfgram and Golden, 2001). A contact metamorphism aureole in the metasedimentary rocks surrounds the ultramafic bodies and thin mafic sills (Gosse, 1992), reaching sillimanite and cordierite - potassium feldspar conditions within 5 m of the intrusions. Quartz and mica have recrystallized to equigranular, non-schistose textures within about 80 m of the main intrusion. Metasedimentary rocks were perhaps subject to brittle fracturing and dilational opening that provided natural pathways for sulfide-rich hydrothermal fluids (Holman, 1999). A major episode of upright folding, observed in most lithologies at all scales, overturned the ultramafic bodies post-emplacement, and they are currently eastward-dipping (Table 3.3). The ultramafic rocks have undergone varying degrees of metamorphism up to low - medium grades (Klerkx et al., 1987; Tack et al., 1994), but large volumes only underwent minor deuteric alteration of olivine and partial serpentinization (Evans et al., 2000). Alteration of the ultramafic rocks is considered to be contemporaneous with emplacement of the granitoid intrusions (Holman, 1999; Maier, 2001). 57 Mica schist KABANGA MAIN wwwwi Coarse-grained pendotite • # Mica schist w ^ >i A X / J Gabbronorite KABANGA NORTH MSSX Sills Fin™rained peridotite Sills SAG schist marker Muscovite-andalusite schist < Quartzite Figure 3.4: Schematic geological cross-section of the Kabanga North and Main bodies, indicating the types of sulfide concentrations and their locations relative to the ultramafic host rocks. F.g. (fine grained) peridotite and eg (coarse grained) peridotite likely represent pyroxenite and peridotite, respectively. Sills typically consist of diabase. The SAG schist marker is characterized by a staurolite-andalusite-garnet (SAG) assemblage. Sulfides occur as disseminated (DSSX) and massive (MSSX). Modified after Evans et al. (2000). 58 Table 3.3: Summary of metamorphic and deformation events within the metasedimentary country rocks and mafic-ultramafic intrusions, in approximate chronological order (Holman, 1999). Timing Lithology Event Effects on Physical Properties 1 Unknown Sedimentary country rocks Sedimentary country rocks Mafic-ultramafic bodies Mafic-ultramafic bodies Sedimentary country rocks and mafic-ultramafic bodies Mafic-ultramafic bodies Low-to-medium grade metamorphism during Kibaran orogeny Intrusion of mafic-ultramafic bodies developed aureole of thermal metamorphism in surrounding metasedimentary rocks Deuteric alteration during emplacement Serpentinization and low-to-medium grade metamorphism upon intrusion of granitic plutons. Upright folding arid overturning during metamorphism Serpentinization and remobilization of sulfide ores Likely slightly increased density, through production of metamorphic minerals, and susceptibility, due to the conversion of pyrite to pyrrhotite at high temperatures. Insignificant effects on susceptibility, minor increases in density Reduction in density due to destruction of olivine. Reduction in density due to replacement of olivine. Likely affected the texture of the dense magnetic minerals, but no change in mineralogy. Therefore, the only changes in physical properties would likely be related to anisotropy. Reduction in density due to replacement of olivine with serpentine. Increased susceptibility because of magnetite produced 3.3.2 Local Geology The Kabanga deposits are located within the 350 km long Kabanga-Musongati mafic-ultramafic alignment (Deblonde and Tack, 1999). Sulfide deposits are associated with mafic-ultramafic intrusions hosted by muscovite-andalusite and biotite-staurolite schists on the eastern flank of the Rubona quartzite ridge (Evans et al., 2000) (Figure 3.2). These metasedimentary rocks consist predominantly of quartz, with minor amounts of muscovite. Magnetite, pyrrhotite and pyrite occur in small amounts (Table 3.4). 59 Table 3.4: Summary of the main rock types at Kabanga, including country rocks (metasedimentary), mafic-ultramafic host rocks and mineralized host rocks (semi-massive to massive sulfide)1 . Rock Type Diabase Gabbro Pyroxenite Peridotite Semi Massive Sulfide Massive Sulfide Meta sedimentary Sample (2.5 inches tall unless otherwise indicated) Thin Section Description Cumulus px, plag, amph Cumulus px Fine-medium ol, spinel, Cumulus fine ol, fine Intercumulus phlog, qtz, rutile, spinel, ilm and sulfides (py, po with blebs of cpy and pn) Intercumulus CPX, plag, amph, phlog, spinel, and sulfides (po with blebs of cpy and pn). fine CPX, coarse poikilitic OPX cumulates. Interstitial phlog, ilm, CPX, plag, and sulfides. CPX, coarse OPX, and spinel. Interstitial px, phlog (with laths of ilm) and sulfides (po with blebs of cpy and pn) Cumulus ol, CPX, and OPX. Sulfides (po with exsolution blebs of pn and cpy), phlog, and OPX as interstitial phases. Po with exsolution blebs of pn and cpy (with basketweave bornite) and py. Spinel/mgt as cumulates Bedding of qtz, muscovite, biotite, plag, amph, and py. Mgt occurs as very fine disseminated grains. Alteration Saussurization of plag and replaced by amph during greenschist metamorphism. Mgt replaced ilm and px. Px replaced with amph then talc. Plag altered to chl, biotite and amph. Serpentinization Replacement and remobilization of sulfides Ol pseudomorphed by serp, mgt and sulfides. Alteration of px to amph and serp. Mgt replacing sulfides and ilm. Ol pseudomorphed by serp and mgt, with lesser amph. Px altered to amph, serp and mgt. Remobilization of sulfides into silicates Sulfides as fine, angular grains replacing fenomagnesian minerals with serp, amph and mgt Mgt replacing sulfides. Mgt occurs filling fractures in sulfides and replacing spinel. Late veins of py Development of porphyroblasts during metamorphism that have been retrogradely altered to qtz and muscovite. Hematite alteration of mgt Abbreviations are as follows: amph = amphibole, Cpx = clinopyroxene, cpy = chalcopyrite, ilm = ilmenite, mgt = magnetite, ol = olivine, Opx = orthopyroxene, phlog = phlogopite, plag = plagioclase, pn = pentlandite, po = pyrrhotite, px = pyroxene, py = pyrite, qtz = quartz, serp = serpentine. Detailed rock descriptions can be found in Appendix J. © The two main massive sulfide deposits, Kabanga Main and Kabanga North (Figure 3.2), are hosted by discontinuous ultramafic pods joined by marginal gabbroic rocks with finer-grained diabase dykes (Figure 3.4). Ultramafic to mafic layered intrusion complexes consist of cyclically layered peridotite to pyroxenite cumulate rocks. Kabanga Main is a thin (~5 m) massive sulfide horizon grading 2.3% Ni, wrapped around the western margin of a NNE-trending, 200 - 400 m thick ultramafic sill. The poorly-defined ore zone has a strike length of 650 m and vertical extent of 150 - 200 m (Wolfgram and Golden, 2001). The Kabanga North body is a large (laterally ~420 m), thick (>25 m), steeply westward-dipping (-70°) tabular body grading approximately 2.7% Ni, increasing to 3.21% Ni at depth with local intersections of 10 g/t Pt, Pd and Au (Wolfgram and Golden, 2001). The massive sulfide ore body mantles the western and southern margins (Evans et al., 2000) of a small, pipe-like, sub-vertical ultramafic body (Wolfgram and Golden, 2001). Mineralized zones within both Kabanga North and Main are composed of net-textured sulfide minerals in peridotite and less commonly pyroxenite, or as massive sulfide lenses (Table 3.4). Pyrrhotite is the dominant sulfide mineral. Pentlandite and chalcopyrite are present in varying amounts as exsolution blebs in pyrrhotite. Spinel occurs as cumulus grains. Magnetite occurs in minor amounts filling fractures and veinlets within the sulfide minerals. Semi-massive sulfide consists of cumulus olivine and pyroxene with interstitial sulfides and lesser spinel. Serpentinization is pervasive and resulted in significant production of secondary magnetite at the expense of ferromagesian and sulfide minerals and spinel. Despite the abundance of magnetic pyrrhotite and magnetite within the massive sulfide lenses of Kabanga Main and North, these deposits occur as elongate lows in magnetic data (Figure 3.5), due to the prevalence of remanence. The Kabanga deposits form dense gravity anomalies (Figure 3.6), as expected, due to the presence of dense massive sulfide bodies within low-density metasedimentary and serpentinized ultramafic rocks. 61 Figure 3.5: A) Reduced to the Pole Aeromagnetic Map of the East African Nickel Belt. The areas outlined in black represent known nickel occurrences, names in yellow. B) Enlarged magnetic map of the Kabanga area based on ground magnetic surveys. Kabanga Main and North occur as magnetic lows due to the presence of remanent magnetism (Modified after Livesey and Murgatroyd, 2003, courtesy of the Kabanga Nickel Company, 2003). 62 Figure 3.6: Gravity data covering the Kabanga area, adjusted using a complete Bouguer anomaly. White circles indicate approximate locations of the Kabanga Main (to the south) and North (to the north) deposits. Black dotted lines show where gravity data was collected. Ultramafic (pyroxenite to peridotite) rocks consist of cumulus olivine, spinel and clinopyroxene within poikilitic clino- and orthopyroxene and interstitial sulfide minerals (pyrrhotite with exsolution blebs of pentlandite and chalcopyrite). Olivine, and partially pyroxene, has been replaced by serpentine, magnetite and lesser amphibole. Gabbro consists of cumulus pyroxene with interstitial clinopyroxene, phlogopite, plagioclase, spinel and sulfide minerals (pyrrhotite with exsolution blebs of pentlandite and chalcopyrite). Pyroxene minerals have been weakly to moderately altered to serpentine and amphibole. Diabase consists of saussurized plagioclase, pyroxene and amphibole with interstitial phlogopite, ilmenite, and sulfide minerals (pyrrhotite, pentlandite, and chalcopyrite). The mineralized mafic-ultramafic complexes are interpreted to have formed as feeder conduits to overlying large layered bodies, which have been removed by subsequent tectonic events and erosion (Holman, 1999). Fractional crystallization of an initial pulse of picritic basalt has proposed for the formation of the ultramafic cumulates, and differentiation of secondary injections of olivine tholeiitic basalt formed the gabbro subzone. Sulfides then either segregated up-stream and were entrained and upgraded by the flowing magma, or were formed broadly in situ and were stirred up by later surges of magma (Maier, 2001). A Ni-rich sulfide fluid phase developed at some stage of igneous and tectonic activity. It was sufficiently mobile to be extruded and emplaced some distance away from the parental basaltic magma body in structural traps and at contact zones with the metapelite (Holman, 1999). Massive sulfide lenses are 63 detached from associated mafic-ultramafic layered complexes to varying degrees at both Kabanga North and Main (Figure 3.4). 3.4 Physical Properties of the Kabanga Ultramafic Complex Lithologies Physical property characteristics were determined for the ore, mafic-ultramafic and sedimentary rocks. Density and magnetic susceptibility were measured from 137 hand samples collected from drill core (herein referred to as "the samples"), representing the different rock types and degrees of alteration. Magnetic susceptibility (MS) was measured at five random points along the length of each hand sample, typically around 10 cm long, and the measurements were then averaged. Physical property histograms and statistics were produced for the Kabanga rock types from the samples (Table 3.5; Figure 3.7) and a database (herein termed "the database") of over 23,000 physical properly measurements (courtesy of Barrick Gold Corporation) (Appendix K) . Differences between physical property statistics for the samples and the database (Table 3.7) can be attributed to the larger, thus perhaps more representative, sample size of the database. However, the size of the database also increases the chance for misidentification of samples, use of different measurement techniques throughout time, and errors in measurement. Physical property distributions of the ultramafic rocks from the database appear to be skewed, potentially as a result of more thorough sampling of lower density serpentinized ultramafic rocks. Table 3.5: Average physical properties , 5 , with standard deviations (st dev), of the rock types at Kabanga. Magnetic Susceptibility (10'3 SI) Density (g/cm3) Average St Dev Average St Dev Diabase 2.1 +14.7 -0.3 3.14 0.51 Gabbro 2.7 +9.9 -0.7 3.12 0.36 Pyroxenite 44.3 +291.4 -6.7 2.94 0.16 Peridotite 67.6 +172.0 -26.6 2.95 0.21 Semi-massive Sulfide 53.9 +735.4 -4.0 3.26 0.40 Massive Sulfide 53.9 +133.6 -28.9 4.47 0.28 Metasedimentary rock 1.5 +7.8 -0.3 2.81 0.08 The magnetic susceptibility mean and standard deviation were calculated for a lognormal distribution, as described by Davis (2002). Density statistics were calculated for a normal distribution. 64 D I A B A S E N=12 mean=11.8085 std dev=19.88644 N=12 mean=0.3133591 Sid dev=0.8533875 N=12 mean=3.1415 std dev= ~ \ — r 0 7 14 21 28 35 42 49 56 63 70 "1 ° -0-5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 MS Log MS Density GABBRO N=10 mean=6 055001 std dev=9.326525 N=10 mean=0 4237561 std dev=0 5702889 N = I O mean=3 1244 std dev=0 3563392 9 I 1 1 1 1 1 1 1 1 1 1 4 I — r i 1 1 r 12 16 20 24 28 32 36 40 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 MS Log MS P Y R O X E N I T E N=19mean=95.68001 std dev=92.15456 II— I I I ICUI I— I . / I 53UJ aiu UOV-U.UiJO lot 12 11 N=19mean=1.719905 std dev=0.6256184 - | — r — r — r -3.0 3.5 Density N=19 mean=2.981631 std dev=0.1723424 T — I — I — r 0 40 80 120 160 200 240 280 320 360 400 -1 MS Log MS P E R I D O T I T E I mean=85.63 std dev=55.20382 T -N=31 mean=1.750439 std dev=0.5889166 N=32 mean=2 937062 std dev=0.2027555 r 300 -1.5-1.0-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 2 .5 Log MS 3.0 3.5 Density 65 SEMI MASSIVE SULFIDE N=21 mean=199.1376stddev=205.5338 N=21 mean=1.930119 std dev=0.783902 N=21 mean=3.354048 std dev=0.3573205 MASSIVE SULFIDE Log MS Density Figure 3.7: Histograms of magnetic susceptibility and density distributions of each rock type, as measured from hand samples. Magnetic susceptibility (MS) has units of 10 ' SI, density is measured in g/cm3. The vertical axis for all of the plots represents the frequency of samples occurring in each range. Black lines are normal distributions calculated by Igpet (Carr, 2005) for each distribution. N is the number of samples for each rock type, mean and standard deviation (std dev) were presumably calculated for normal distributions. 66 Table 3.6: Comparison of magnetic susceptibility and density distributions (Dist.) for the samples collected for this thesis ("samples") and drillhole database ("database") assembled by Kabanga Nickel Company. Magnetic Susceptibility (10 3 SI) Density (g/cm3) Dist. of Dist. of Difference Dist. of Dist. of Difference in Samples Database in Means Samples Database Means Diabase Lognormal or bimodal Skewed lognormal 0.39 Skewed normal Normal to skewed to bimodal 0.046 Gabbro Lognormal Undetermined -11.78 Normal or bimodal Skewed normal 0.055 Pyroxenite Lognormal Lognormal 35.95 Normal or bimodal Skewed normal -0.058 Peridotite Lognormal Skewed lognormal 55.22 Normal Skewed normal -0.064 Semi-massive Sulfide Lognormal Lognormal 47.65 Normal to skewed Skewed normal 0.188 Massive Sulfide Lognormal Skewed lognormal 47.69 Normal Skewed normal 0.052 The natures of the distributions were assessed visually, and means were calculated for the suitable distributions (normal or lognormal). Differences between means for the collected samples and whole database were calculated as mean(sanipies) minus mean( d a t a b a s e ). 3.4.1 Magnetic Susceptibility Metasedimentary rocks, diabase and gabbro are generally characterized by low susceptibilities (Table 3.5). Massive sulfide has moderately high susceptibility. Ultramafic rocks (peridotite, pyroxenite) that tend to contain magnetite are highly susceptible; the ultramafic rocks with higher sulfide contents (e.g. semi-massive sulfide) have the highest susceptibilities. Thus, samples with high susceptibilities tend to have more abundant sulfide (pyrrhotite) and oxide (magnetite, ilmenite, chromite) minerals. Pyrrhotite is a primary sulfide mineral whereas magnetite was produced during serpentinization at the expense of ferromagnesian and sulfide minerals. Magnetic susceptibility characteristics of the Kabanga lithologies therefore appear to be a function of both primary and secondary processes. Quantifying the relationship between the abundance of magnetite and pyrrhotite and susceptibility may provide insight into the relative importance of the effects that serpentinization and mineralization have on magnetic susceptibility. The abundance of magnetite is statistically related to magnetic susceptibility in the Kabanga mafic-ultramafic rocks (Figure 3.8A). In massive sulfide samples, magnetic susceptibility is a function of monoclinic pyrrhotite content (Figure 3.8B). Because susceptibility is controlled by the abundance of two 67 different iron-bearing minerals, the relationships between susceptibility and ferric, ferrous or total iron are not statistically significant (Figure 3.9). 1000 - Diabase * Gabbro * Pyroxenite 8 Peridotite • Semi-Massive Sulfide • Massive Sulfide 8 10 12 14 Modal % Magnetite 16 18 20 wt% Monoclinic Pyrrhotite Figure 3.8: A) Relationship between modal % magnetite (estimated visually during petrographic work) and magnetic susceptibility for the Kabanga rock types. Errors on magnetite estimates vary from 1-5%. B) Relationship between magnetic susceptibility and the amount of monoclinic pyrrhotite, as quantified from X-ray diffraction patterns using the methods of Arnold (1966) and Graham (1969), for the massive sulfide samples. 68 1000 05 Q. U o o c O) i Fe 2 0 3 0.01 XTotal Fe A Fe203 • FeO 10 20 30 40 50 wt % Iron 60 70 80 90 100 Figure 3.9 Plot illustrating relationships between ferric, ferrous and total iron and magnetic susceptibility, for all rock types comprising the Kabanga ultramafic intrusions and associated mineralization. Geochemical analyses used to produce this plot can be found in Appendix L. Total Fe represents the iron content reported as Fe 20 3. 3.4.2 Density Mineralized, mafic-ultramafic and country rocks of the Kabanga intrusion tend to have relatively distinct densities (Table 3.5). Metasedimentary rocks typically have low densities, as do the ultramafic rocks (pyroxenite, peridotite). Diabase and gabbro have moderate densities. Semi-massive and massive sulfide are characteristically most dense. Differences in density characteristics between rock types are driven by differences in mineral assemblages, which result from variable effects of primary and secondary geologic processes. The effects of primary sulfide mineralization on density can be represented by pyrrhotite content, the dominant sulfide mineral. A statistically valid relationship exists between density and pyrrhotite content (Figure 3.10), indicating that density is significantly influenced by the addition of sulfides. Serpentinization tends to cause density to decrease (Komor et. al., 1985; Toft et al., 1990; and Measday, 2004). This secondary alteration process may be quantified by H20 + , which 69 quantifies the amount of water within mineral structures including serpentine (Appendix L). However, amphibole, resulting from metamorphism, and phlogopite, a primary igneous mineral, also contribute to H 2 0 + . As such, H 2 0 + in these samples represents more than the degree of serpentinization. A direct relationship is expected between serpentinization and density, and density does decrease with increased H2<D+, but H 2 0 + is statistically uncorrelated with density (Figure 3.11 A). Density does relate to magnetite content (Figure 3.1 IB), which can also be used as a proxy for the degree of serpentinization as it only occurs in the Kabanga rocks as a product of serpentinization. 4.5 o c Q 3.5 • X X _ IK 2.5 • •• -Diabase xGabbro i Pyroxenite Peridotite • Semi Massive Sulfide • Massive sulfide 10 20 30 40 50 60 Modal % Pyrrhotite 70 80 90 100 Figure 3.10: Chart illustrating the relationship between density and pyrrhotite, the main sulfide mineral, which acts as a proxy for the degree of sulfide mineralization. 7 0 4.3 4.1 3.9 3.7 u O) 3.5 w c 33 0) Q 3.1 2.9 2.7 2.5 • • - Diabase x Gabbro * Pyroxenite • Peridotite • Semi-Massive Sulfide • Massive Sulfide X • • A X 5 H2O+ 10 B \ 4.5 1 Massive Sulfide I / -Diabase x Gabbro Pyroxenite • Peridotite •Semi-Massive Sulfide •Massive Sulfide '5 X • X £ it A-•Fx * f i • i i 11 *; • . 2.5 X 8 10 12 Modal % Magnetite 14 16 18 20 Figure 3.11: A) Plot illustrating the relationship between density and H 2 0 + , which quantifies the amount of water within minerals like serpentine, amphibole and phlogopite. B) Relationship between density and magnetite as an indicator of the degree of serpentinization. Geochemical data used in this plot can be found in Appendix L. 71 3.4.3 Quantitative Relationships Between Serpentinization and Physical Properties Studies have quantified the strong relationship between density, magnetic susceptibility and serpentinization in various barren ultramafic bodies, including the North Arm Mountain massif (Newfoundland, Canada), Burro Mountain (California, USA), Red Mountain (California, USA), Josephine Peridotite (Oregon, USA) and Dun Mountain (New Zealand) (Saad, 1969; Komor et. al., 1985; Toft et al., 1990; and Measday, 2004). Density (D, kg/m3 xlO3) can be predicted based on the degree of serpentinization (%S): D = 3.264 - 0.00748(%5') (Komor et al., 1985) (3.1). Likewise, an exponential relationship appears to exist between magnetic susceptibility (K, SI) and density: log10(#) = -1.95(D) + 3.28 (Toft et al., 1990) (3.2). The applicability of these equations to rocks with variable sulfide mineral contents was tested in this study (Appendix M). These equations were used to predict density using the optically estimated modal amount of serpentine at Kabanga. Magnetic susceptibility was then calculated from the calculated density. Comparing calculated physical properties to measured values for each sample illustrates that density is relatively well-predicted for barren mafic-ultramafic rocks, which are similar to those used to establish these correlations. Therefore, these relationships accurately calculate density from serpentine, and vice versa, in barren mafic-ultramafic rocks at Kabanga. However, density is drastically underestimated for semi-massive sulfide rocks (Figure 3.12A). This quantitative relationship between density and serpentine is obviously invalid for rocks with significant amounts of sulfide minerals. Magnetic susceptibility calculated from calculated density was orders of magnitude less than measured values for both barren mafic-ultramafic rocks and sulfide mineral-bearing rocks (Figure 3.12B). Calculated susceptibilities of mineralized samples are likely complicated by errors in the calculated density, and by the presence of magnetic pyrrhotite. Consequently, these quantitative physical property-mineralogy relationships are not expected to hold true for any mineralized ultramafic complexes. Furthermore, underestimation of susceptibility in the barren mafic-ultramafic rocks illustrates that the density - susceptibility relationship observed in other ultramafic rocks is not applicable at Kabanga. 72 A) Density 40 -30 B) Magnetic Susceptibility . . 100 "O O m,B o i_ 50 a. T3 o 3 0 (0 (0 Q) -50 ibil Q. o . -100 (0 3 </> -150 T Gabbro Pyroxenite r A . V Peridotite Semi Massive Figure 3.12: Charts showing misfits between measured and calculated density (A) and magnetic susceptibility (B), calculated as (measured - predicted)/measured value x 100%. Values greater than zero indicate where density and magnetic susceptibility has been underestimated. 73 3.4.3.1 Remobilization of Metals and Sulfide Minerals during Serpentinization Sulfide minerals in magmatic sulfide deposits around the world have been remobilized on the scale of millimetres to kilometres during a variety of post-emplacement processes, including serpentinization (Marshall and Mancini, 1994) and low- to high-grade metamorphism (Willett et al., 1978). Examples include the Bushveld Complex (Li et al., 2004); the Worthington offset of the Sudbury Igneous Complex (Stewart, 2002); Kambalda (Heath et al., 2001); and the Agnew (Perseverance) Nickel deposit (Barnes et al., 1988). Massive sulfide bodies of the Kabanga Main and North deposits are slightly detached from the ultramafic complexes, suggesting that the ore has already experienced remobilization. Textures observed during petrographic analysis indicate that sulfide minerals within the Kabanga ore bodies have been remobilized during serpentinization, as sulfide minerals are commonly intergrown with secondary serpentine and amphibole (Figure 3.13). It is essential to know if sulfide ore has been significantly remobilized due to serpentinization, as mineralization could then be concentrated outside of the deposits currently being explored. A negative correlation between metal content and degree of serpentinization may suggest that serpentinization has caused metals to be mobilized beyond the hand sample scale (e.g. Marshall and Mancini, 1994; L i et al., 2004). The degree of serpentinization, quantified by magnetite abundance, does not appear to correlate to ore content in the Kabanga samples (Figure 3.14 A and B), suggesting that remobilization has not occurred on significant scales. Figure 3.13: Microphotograph of pyrrhotite (Po) being replaced by magnetite (Mgt) and intergrown with serpentine ("shards" intergrown with brown gangue). Pn is pentlandite, Cpy is chalcopyrite. 74 10000 9000 8000 E 7000 Q. 0) 6000 o c ra c 5000 < «- 4000 UJ * ; • • Ni C u » 3000 2000 1000 • • • • • • • • • • • • ul M 11 • • ' B 8 10 12 Modal % Magnetite 14 16 18 20 0.7 0.6 0 5 04 E a 5 (A 8 S B (0 T3 C 3 < 0.3 c 4) I 02 t t t Point at 1.93 ppm Pt and 4.12 ppm Pd Point at 1.055 ppm Pt and 2.26 ppm Pd Point at 1.615 ppm Pd • • • i •R • Pd • • • 8 10 12 Modal % Magnetite 16 18 20 Figure 3.14: A) Relationship between base metals (nickel and copper) and magnetite, as a proxy for the degree of serpentinization. The maximum metal abundance measurable by the chosen technique is 10000 ppm. Geochemical analyses used in these plots are available in Appendix K. B) Relationship between precious metals (platinum and palladium) and magnetite, as a proxy for serpentinization. 75 Although remobilization has not resulted in removal of metals, serpentinization has altered the original sulfides. O'Hanley (1996) states that magmatic sulfides have sulfide:magnetite ratios of 8:1 for disseminated ore and 50:1 for massive ore. Ratios less than these suggest partial replacement of pyrrhotite with magnetite. Pyrrhotite to magnetite ratios in the disseminated sulfide samples at Kabanga are mostly less than 8:1 (Figure 3.15), suggesting that pyrrhotite has been commonly replaced by magnetite. Few massive sulfide samples have ratios less than 50:1 pyrrhotite to magnetite, suggesting that massive sulfide has been locally been replaced by magnetite. Petrographic analysis confirms this conclusion (Figure 3.13). Although this replacement has not significantly altered the ore content of the sulfide mineral-bearing rocks at Kabanga, replacement of moderately high susceptibility pyrrhotite with high susceptibility magnetite would have an effect on susceptibility. 7C0 Pyrrhotite/Magnetite A Pyroxenite • Peridotite • Semi Massive Sulfide • Massive Sulfide 1000 Figure 3.15: Plot of magnetic susceptibility and the pyrrhotite/magnetite ratio. The solid black line represents the 8:1 ratio of sulfides to magnetite that is typical of disseminated sulfides that have not been altered. The dashed line represents the 50:1 ratio of pyrrhotite to magnetite, under which massive sulfide ore has been replaced by magnetite (O'Hanley, 1996). This plot illustrates that many samples have experienced replacement of pyrrhotite with magnetite during serpentinization. 7 6 3.4.4 Statistical Correlation Analysis of Geological and Geophysical Properties Correlations between different geological and geophysical parameters were calculated for a subset of the Kabanga data to assess whether mineralogy can be statistically related to and therefore predicted from physical properties for the Kabanga ore bodies. Consequently, Principal Component Analysis was performed to establish whether a set of factors, representing geological processes, could be extracted to explain the aforementioned correlations between geologic variables, including mineralogy and physical properties. Linear combinations of these factors (i.e. geologic process) can then be used to represent each variable (e.g. physical properties of mineralogy). Correlations between variables were calculated, and significant correlations at the 95% confidence level were identified (Appendix N). Magnetic susceptibility was determined to correlate most strongly with magnetite content, but also correlates directly with the intrusive body (higher in North body), rock type, loss-on-ignition (LOI), platinum (Pt), palladium (Pd), and serpentine content and inversely with weight percent SiC>2 (silica content). LOI represents the amount of volatiles removed from the rocks upon heating and is generally used to quantify the amount of hydrous minerals, including serpentine but also includes any sulfur lost upon heating. Density correlates most strongly with Fe203, but also correlates significantly in a positive sense with rock type, LOI, all metals (base and precious), pyrrhotite, and chalcopyrite. Density correlates significantly in an inverse sense with silica, magnesium, clinopyroxene, and serpentine. Six factors out of 27 were determined to be meaningful (Figure 3.16) using Kaiser's criterion (1958). They describe 76.9% of the variance in the data. These factors appear to represent certain geological processes or characteristics. The potential meaning of these factors as geological features was interpreted based on the geologic variables that correlate with each factor, and factor loadings for each variable as a measure of correlation strength (Table 3.7): Factor one (FI) represents sulfide mineralization, in that it correlates with metal contents and rock type. Furthermore, density correlates most strongly with factor one, reaffirming that density is primarily controlled by the abundance of sulfide minerals. Factor two (F2) represents serpentinization, as it correlates with intrusive body, magnetic susceptibility, serpentine and magnetite content. Therefore, magnetic susceptibility is primarily a function of magnetite produced during serpentinization. The degree of serpentinization, and susceptibility accordingly, varies between intrusive bodies, as was observed during the petrographic study. Furthermore, factor two also correlates weakly with PGE (Au, Pd, Pt) 77 content, suggesting that the precious metals have been remobilized and concentrated in the serpentinized rocks. Factor three (F3) also seems to represent alteration, as it is correlated with LOI and the PGE. It may indicate hydration of the ferromagnesian minerals and concentration of PGE by a mechanism like chromatographic separation (Boudreau and Meurer, 1999). Factor four (F4) correlates with intrusive body, amphibole, clinopyroxene and olivine contents. It likely represents the primary mineralogy of the ultramafic intrusions. It does not relate significantly to either susceptibility or density, suggesting that the original mineral assemblage of the intrusive bodies no longer influences physical properties due to the effects of mineralization and alteration. Factor five (F5) relates inversely to depth and directly to sulfide content (pentlandite, chalcopyrite, pyrrhotite). This factor may represent concentration of massive sulfide at the original base of the intrusions, which have now been overturned. Factor six (F6) relates to magnetic susceptibility and magnetite, and may not be significant, as it appears to repeat factor two. 11 10 F1 > Kaiser's Criterion: Significant correlations have eigenvalues > 1 F2 F16 F17 F18 F19 F 2 0 F21 F22 F23 F24 F25 F26 F27 Figure 3.16: Eigenvalues (vertical axis) for the factors (F#) calculated by XLSTAT. The Kaiser criterion (Kaiser, 1958) was applied to determine that factors 1-6 are significant, since they have eigenvalues greater than one. 78 Table 3.7: Table displaying the loadings 1 7 for the factors (F#) calculated by the principal component analysis. F1 F2 F3 F4 F5 F6 Interpreted geologic process Sulfide mineralization Serpentinization Alteration Primary mineralogy Depth Repeat of F2 Depth (m) 0.139 -0.192 0.166 0.056 -0.568 -0.383 Ore Body 0.039 0.606 0.096 -0.546 0.006 -0.046 Rock Type 0.638 0.206 -0.297 0.301 0.206 -0.142 Susceptibility . 0.174 0.642 -0.375 0.060 -0.217 -0.363 Density 0.887 -0.227 -0.017 -0.052 -0.142 0.044 S i0 2 -0.883 -0.072 0.267 -0.060 0.168 -0.180 Fe 2 0 3 0.937 -0.124 -0.173 -0.050 -0.148 0.006 MgO -0.738 0.420 -0.149 0.270 0.010 0.114 Loss-on-lgnition 0.439 0.392 -0.539 0.075 -0.061 0.444 Cobalt 0.894 0.046 0.209 0.085 -0.053 0.195 Copper 0.766 -0.119 0.193 -0.041 0.085 0.186 Iron 0.959 -0.062 -0.195 -0.010 -0.129 -0.005 Nickel 0.863 -0.023 -0.125 -0.006 -0.096 -0.061 Sulfur 0.809 -0.181 -0.219 0.098 -0.104 -0.188 Gold 0.477 0.511 0.610 0.175 -0.079 0.098 Platinum 0.485 0.569 0.551 0.209 -0.186 0.006 Palladium 0.486 0.575 0.582 0.202 -0.085 0.034 Amphibole -0.311 -0.012 0.146 -0.674 -0.263 0.117 Clinopyroxene -0.411 -0.021 -0.002 0.202 -0.268 -0.121 Orthopyroxene -0.296 -0.388 0.144 0.646 -0.028 -0.250 Olivine -0.212 -0.156 -0.067 0.691 -0.063 0.238 Serpentine -0.342 0.639 -0.383 0.186 -0.026 0.144 Pyrrhotite 0.824 -0.146 -0.051 0.031 0.336 0.020 Pentlandite 0.344 0.215 0.245 0.043 0.685 -0.191 Chalcopyrite 0.494 -0.014 -0.032 -0.080 0.434 -0.211 Magnetite -0.025 0.724 -0.325 -0.058 0.024 -0.347 Values in bold indicate the properties that correlate with each factor. Non-quantifiable variables were assigned numerical values, such as Ore body: Main = 0, North = 1; Rock Type: Metasedimentary = 0, Diabase = 1, Gabbro = 2, Pyroxenite = 3, Peridotite =4, Semi-massive sulfide = 5, Massive Sulfide = 7. 3.5 Mineral Prediction Filter As geological and geophysical properties of the Kabanga mineralized and mafic-ultramafic rocks are statistically correlated, estimation of mineralogy based on susceptibility and density is feasible with a reasonable degree of confidence. The Mineral Prediction Filter developed by Williams and Dipple (2005) calculates ore mineralogy (pentlandite, pyrrhotite, pyrite, magnetite) from susceptibility and density according to the equations: 79 kmgt f mgt + kpyfpy ^pnfpn + ^pofpo + ^ host fhost ~ ^ Pmgt fmgt Ppyfpy Ppnf pn Ppofpo ~^ Phost f host = ^ (3-3) fmgt ~f ^ / 7 n f po f host ^ where k is the susceptibility of each individual component (magnetite (mgt), pyrite (py), pentlandite (pn), pyrrhotite (po), host rock (host)), p is density (in g/cc) of each component, f is the volume fraction of the component (from 0 to 1), K is susceptibility of the rock sample, and D is density of the rock sample. Ore mineral abundances were calculated with two different objectives, to minimize or maximize the sulfide content. Calculated ore mineral abundances were compared to optically estimated modal mineral abundances (Figures 3.17) to establish the validity of the Mineral Prediction Filter for Kabanga rocks. Pentlandite and pyrite abundances are generally overestimated by both the maximized and minimized sulfide programs (Figure 3.17). Magnetite is typically also underpredicted by both programs. The minimized sulfides program generally underestimates the pyrrhotite content while the maximized sulfides program typically overestimates the abundance of pyrrhotite in the mafic-ultramafic rocks. However, both the minimized and maximized programs underestimate the abundance of pyrrhotite in massive sulfide and many semi-massive sulfide samples. Hexagonal pyrrhotite is both over- and underestimated. The amount of monoclinic pyrrhotite is greatly underestimated in both the minimized and maximized sulfide versions (Figure 3.18). Consistent underestimation of magnetite and pyrrhotite abundance may reflect demagnetization effects, described as when the susceptibility of rocks with abundant pyrrhotite or magnetite is no longer linearly related to the magnetic mineral content (Telford et al., 1990; Clark, 1997). Additionally, physical property averages of the host rock or minerals (e.g.pyrrhotite) could be inaccurate; the relationship between monoclinic pyrrhotite and magnetic susceptibility indicates that the susceptibility of pyrrhotite may be different than the value used by the Mineral Prediction Filter. Underestimation of pyrrhotite may also occur because the program attempts to maximize the amount of pentlandite, which is subsequently overestimated. The Mineral Prediction Filter identifies all massive sulfide samples and 11 of 17 semi-massive sulfide samples as containing anomalous amounts of sulfide minerals or magnetite. Several semi-massive sulfide samples are not identified as ore despite having the same amount of sulfide minerals as the other semi-massive sulfide samples likely because serpentinization has decreased the density of these samples below that which is expected for ore. The filter correctly recognized diabase, gabbro, pyroxenite and peridotite samples that have anomalous sulfide and 80 oxide mineral contents, but misidentified some mafic-ultramafic samples that only have anomalous amounts of ferromagnesian minerals. 0.8 B Diabase Gabbro Massive Sulfide Semi-Massive Sulfide -0.8 —•—Pyrrhotite —•—Pentlandite —A—Pyrite - • - Magnetite Figure 3.17: Misfit between mineral abundances predicted by the Mineral Prediction Filter (Williams and Dipple, 2005) and mineral abundances estimated optically during petrographic analysis. These misfits were calculated such that overpredictions by the Mineral Prediction Filter are shown as greater than zero. A) Results from the Minimized Sulfides Program. B) Results from the Maximized Sulfides Program. Data involved in these calculations is available in Appendix O. 81 100 0 10 20 30 40 50 60 70 80 90 100 Measured % of Pyrrhotite Polytype Figure 3.18: Comparison of the amount of each pyrrhotite polytype estimated by the Mineral Prediction Filter (Williams and Dipple, 2005) (y-axis) and measured using methods described by Graham (1969) and Arnold (1966) from x-ray diffraction patterns (x-axis) for the massive sulfide samples. The vertical error bars represent the range calculated from the maximized and minimized sulfides versions of the program, while the horizontal axis represents the range of pyrrhotite polytypes calculated from the two x-ray diffraction pattern using the two different methods. The dashed line represents the path along which the estimated amount is equal to the measured amount of each pyrrhotite structure. 3 .5 . 1 . Modeling of Serpentinization and Mineralization Effects of serpentinization on physical properties limit the accuracy of the Mineral Prediction Filter, as low-density anomalies associated with serpentine and associated alteration minerals mask positive density anomalies associated with concentrations of sulfide minerals. To understand the consequences for interpretation of density models of opposing effects of mineralization and serpentinization on density, estimations were made of the percentage of sulfide minerals that could occur in a completely serpentinized rock to produce a density equivalent to a barren host rock. This modeling was performed for diabase (pban-en - 2.8-3.0 g/cm ), gabbro (Pbarren = 2.7-3.3 g/cm ), and peridotite/pyroxenite (Pban-en = 2.78-3.37 g/cm ) barren host rocks. Pervasively serpentinized rock was assumed to consist solely of sulfide minerals (represented by pyrrhotite), serpentine, and magnetite, quantified as 10% of the 82 serpentine content. The following equation was rearranged to calculate the amount of pyrrhotite (x) for an average, a maximized and a minimized sulfide scenario (Table 16): Pbarren = {l ~ X - y)x Pserpenline + {x)x p ^ + {y)x p m a g n e t U e (2) where v = 0.1x(l-x-v). The average scenario employed average densities for all constituents. The minimized sulfide scenario used the minimum density for each barren host rock with maximum densities for serpentine (2.65 g/cm ), magnetite (5.2 g/cm ) and pyrrhotite (4.8 g/cm ). The maximized sulfide scenario involved the maximum barren host rock density and minimum densities for serpentine (2.5 g/cm3), magnetite (4.9 g/cm3) and pyrrhotite (4.5 g/cm3). The maximum amount of sulfide minerals that could occur within a serpentinized rock without causing a density anomaly is almost 50%, which is obviously very significant (Table 3.8). However, the susceptibility of barren host rocks would be significantly less than that of serpentinized semi-massive sulfide, illustrating that it is crucial to use a combination of physical properties to identify mineralized samples. Electromagnetic methods may also be valuable for detecting conductivity anomalies associated with sulfide-rich rocks. Magnetic susceptibilities or conductivities were not considered in this basic modeling exercise, despite their usefulness, because the relationship between these physical properties and mineral abundance are much more complex. Table 3.8: Results from modeling of densities for mineralized and serpentinized samples, showing the calculated amount of pyrrhotite that can occur in a serpentinized rock to produce the same density as a barren diabase, gabbro or peridotite/pyroxenite host rock. Host Rocks Average Case Minimum Case Maximum Case Diabase 7.2 -5.7 21.2 Gabbro 14.5 -12.7 43.8 Peridotite 19.9 -7.1 49.1 3.6 Discussion This chapter presented qualitative and quantitative relationships between physical properties, rock type and mineralogy resulting from the effects of primary and secondary geologic processes common in magmatic sulfide deposits. Density and magnetic susceptibility characteristics of different Kabanga rock types are discussed in the context of primary and secondary mineral assemblages characteristic of each rock type. Consequently, implications of physical property -83 mineralogy relationships for prediction of ore mineral abundance based on physical properties are considered. 3.6.1 Density Density of mafic-ultramafic and sulfide mineral-bearing rocks at Kabanga is a function of two opposing processes, mineralization and serpentinization. The least dense rocks are pervasively altered ultramafic rocks (pyroxenite and peridotite), in which ferromagnesian minerals have been mostly replaced by serpentine and amphibole, and metasedimentary rocks, which consist primarily of low-density minerals, such as quartz, mica, feldspar, etc. Mafic rocks (gabbro and diabase) that are relatively fresh have moderate densities, due to the presence of preserved ferromagnesian minerals. The densest samples are those with high sulfide mineral contents (semi-massive and massive sulfide). Sulfide mineralization is the primary controlling factor on density of the Kabanga rock types, as demonstrated by the statistically significant correlation between density, sulfide mineral abundances and metal contents (Figure 3.10). Principal Component Analysis also revealed that most of the variability in density can be explained by one factor interpreted to represent mineralization as it correlates strongly with metal contents. Density is thus the best individual indicator of sulfide mineral contents. However, serpentinization causes a drastic reduction in density of ultramafic samples and even semi-massive sulfide hosted by ultramafic rocks, as demonstrated by the inverse relationship between magnetite and density (Figure 3.1 IB), with magnetite being used as a proxy for serpentinization. Although serpentinization has a clear effect on density, quantifying this effect was difficult in sulfide-bearing samples, because of the opposing effects of mineralization and serpentinization on density create an inherent ambiguity (i.e. a rock with a given density can have many different of serpentine - sulfide mineral contents). Because of the effects of serpentinization on density, estimations of sulfide and oxide mineral abundances from physical properties tend to be inaccurate in serpentinized rocks. Physical properties other than, or in addition, to density are thus required to quantitatively identify sulfide mineralization in serpentinized samples. 3.6.2 Magnetic Susceptibility Magnetic susceptibility of the Kabanga rock types appears to be highest in samples with abundant magnetite and/or pyrrhotite. Rocks with the most pyrrhotite (massive sulfide), 84 magnetite (peridotite, pyroxenite) or a combination of pyrrhotite and magnetite (semi-massive sulfide) are the most magnetic, in ascending order. The statistically significant relationship between susceptibility and magnetite for the mafic-ultramafic lithologies implies that susceptibility is predominantly controlled by the degree of serpentinization (Figures 3.8A). Furthermore, Principal Component Analysis revealed that much of the variability in magnetic susceptibility can be explained by one factor, interpreted to represent serpentinization as it correlates with both serpentine and magnetite content. In massive sulfide, susceptibility is directly related to the monoclinic pyrrhotite content (Figure 3.8B), since pyrrhotite is the dominant constituent of these samples and magnetite is scarce. Susceptibility is a function of magnetite produced by a secondary process that has little effect on the ore minerals, as sulfide minerals were determined not to have been remobilized. Consequently, susceptibility cannot be directly related to nickel and copper content; it is statistically unrelated to base metal contents for all rock types. Magnetic susceptibility is very useful, however, for identifying serpentinized rocks in which density may have been reduced sufficiently to mask any anomalies associated with accumulations of sulfide minerals. Conversely, susceptibility does correlate with platinum group elements and gold, which occur in minor amounts, suggesting that these elements have been remobilized and concentrated in highly serpentinized rocks. 3.7 Conclusions and Implications for Other Magmatic Sulfide Deposits This study aimed to understand the relationship between physical properties and mineralogy within the context of primary and secondary geological processes. Minerals contributing to physical property anomalies were categorized petrographically, focusing on the dense and magnetic minerals occurring in each rock type and their paragenesis based on texture. The dominant magnetic minerals were determined to be magnetite and monoclinic pyrrhotite. Dense minerals include sulfide minerals, predominantly pyrrhotite but also pentlandite and chalcopyrite; oxide minerals, including magnetite, ilmenite and spinel; and ferromagnesian minerals within the mafic-ultramafic rocks, predominantly pyroxene and olivine. Ferromagnesian minerals were variably replaced by serpentine and magnetite. Similarly, primary sulfide and oxide (ilmenite and spinel) minerals were partially replaced by magnetite. Secondary processes, namely serpentinization, have caused significant mineralogical changes, which consequently modified susceptibility and density. 85 Kabanga rock types were characterized with respect to magnetic susceptibility and density. The different lithological groups (metasedimentary, mafic, ultramafic, semi-massive sulfide and massive sulfide) exhibit relatively distinct physical properties due to significant differences in geologic processes. Metapelite country rocks are distinctively low density and high susceptibility, due to the abundance of quartz and relative lack of magnetite or pyrrhotite. Mafic rocks (diabase and gabbro) typically have low susceptibilities and moderately high densities because they also have small amounts of magnetic minerals but have moderate amounts of ferromagnesian minerals and small degrees of alteration. Ultramafic rocks (pyroxenite, peridotite) at Kabanga generally have low densities and high susceptibilities as they have been variably serpentinized. Semi-massive sulfide samples are dense and highly susceptible because they contain primary sulfide minerals, predominantly pyrrhotite, and magnetite produced by serpentinization. Massive sulfide is most dense and has moderate susceptibilities due to the preponderance of pyrrhotite but relative lack of magnetite. Lithologies composing the Kabanga mafic-ultramafic intrusion appear to have undergone at least two processes that affected magnetic susceptibility and density (Figures 3.19 and 3.20). The original magmatic event controlled the ferromagnesian and sulfide mineral content of the mafic-ultramafic rocks that grade into massive sulfide at the original base of the intrusion. Density is primarily controlled by the abundance of sulfide minerals, but is also significantly influenced by the ferromagnesian mineral content of fresh mafic and ultramafic rocks, which is a function of magma composition and fractional crystallization processes. Therefore, the gravity expression and corresponding physical property anomalies of an unaltered mafic-ultramafic intrusion reflect both sulfide mineralization and primary mineral assemblage. Susceptibility of fresh mineralized ultramafic complexes is predominantly a function of magnetic pyrrhotite content. As such, the magnetic expression of unaltered ultramafic complexes is dominated by anomalies associated with the massive sulfide bodies. 86 100 • o §" 10 o C/) 13 CO o "•+-> CD c CO Massive Sulfide Semi Massive Sulfide Ultramafic o Metasedimentary Mineralization ^^Serpentinization 2.5 3.5 4 Density (g/cm3) 4.5 Figure 3.19: Schematic diagram illustrating relative physical properties of fresh mafic and ultramafic rocks and how physical properties are altered by mineralization (black arrows) and serpentinization (dark grey arrows). F R E S H S E R P E N T I N I Z E D A) Density / - ) ( jHr ( ~* I B) Magnetic Susceptibility Figure 3.20: Schematic diagrams illustrating relative density (A) and magnetic susceptibility (B) of ore, host rocks and country rocks, in a simplified model of a layered igneous intrusion with basal mineralization. Diagrams on the left are for unaltered complexes, while diagrams on the right illustrate physical properties for serpentinized complexes. 8 7 Serpentinization reduces the density of ultramafic rocks, potentially masking density anomalies associated with sulfide mineral concentrations in rocks that have been pervasively serpentinized. Conversely, serpentinization makes density anomalies associated with massive sulfide much more apparent. Therefore, gravity surveys can be very useful when exploring for magmatic sulfides associated with altered mafic-ultramafic intrusions. Addition of magnetite during serpentinization dramatically increases the susceptibility of ultramafic rocks, producing a magnetic expression that overshadows magnetic anomalies associated with massive sulfide. Therefore, the most susceptible unit in altered mafic-ultramafic complexes is likely not the massive sulfide ore dominated by pyrrhotite, but rather the adjacent serpentinized ultramafic complex and semi-massive sulfide occurring with the ultramafic rocks. Thus, interpretation of magnetic susceptibility models must proceed with caution and a good understanding of the effects of secondary geological processes on susceptibilities of rocks associated with magmatic sulfide deposits. Remanent magnetism also poses a serious problem for meaningful interpretation of magnetic data. Resolving the issues that remanent magnetism produce for meaningful interpretation of magnetic susceptibility models was the scope of this study. Calculating sulfide mineral abundances in serpentinized rocks or, conversely, quantifying the degree of serpentinization in mineralized samples was demonstrated to be difficult due to the inherently ambiguous sulfide and serpentine contents in a rock that produce a given density. Therefore, quantitative modeling of geophysical expressions or estimation of ore contents at varying degrees of serpentinization cannot be reliably conducted for serpentinized rocks with appreciable sulfide contents. Quantitative analysis of geophysical data and physical properties can proceed with caution using the Mineral Prediction Filter (Williams and Dipple, 2005) and on a deposit-specific basis, once sufficient data has demonstrated the relationships between physical properties, rock type and ore content with variable alteration. Otherwise, the Mineral Prediction Filter was demonstrated to calculate ore mineral abundances in unaltered mafic-ultramafic rocks and massive sulfide. Magmatic processes, including formation and serpentinization of ultramafic complexes and sulfide ore, invariably occur within magmatic sulfide deposits, and consistently have the same effects on physical properties (Figure 3.18 and 3.19), as described here for the Kabanga deposit. Kabanga can be considered representative of other magmatic sulfide deposits, including extrusive magmatic sulfide occurrences such as komatiites, due to similarities in country rock, mafic-ultramafic units, and mineralization. Therefore, relationships between physical properties and mineralogy, both qualitative with respect to geologic processes and quantitative, as 88 established by the Mineral Prediction Filter (Williams and Dipple, 2005), can be established for all magmatic sulfide deposits, improving the interpretation of geophysical data with respect to rock type and ore content. 89 Chapter 4: Implications of Physical Property - Mineralogy Relationships for Interpretation of Inversions 4.1 Physical Property - Mineralogy Relationships for Kimberlite and Magmatic Sulfide Deposits Geophysical inversion programs have been developed that are capable of calculating three-dimensional physical property models. These models can then be interpreted with respect to geological features (e.g. rock type or ore content) based on physical property distribution of those features, which relate to inferred mineralogical relationships. Building the data necessary to infer these relationships between physical properties and mineralogy for ultramafic rock-hosted mineral deposits is the purpose of this thesis. Of particular importance is the analysis of how various primary and secondary geologic processes affect ore and physical property distributions that might be seen in a three dimensional inversion of magnetic and gravity data. To reach this goal, physical properties were analyzed to gain an understanding of quantitative correlations between mineralogy, magnetic susceptibility and density throughout the history of a deposit. Physical property - mineralogy relationships were studied for two ultramafic rock-hosted deposit types; magmatic sulfide deposits and kimberlite, both of which sought after by the exploration industry for the economic value of their particular commodities (Ni, Cu, Co, PGE and diamond, respectively). Though the two deposit types differ significantly in many aspects, including ore minerals, morphology, magma chemistry, rock types, and primary geologic processes, they share a number of similarities (Table 4.1). Specifically, in both kimberlite and ultramafic-hosted magmatic sulfide deposits, physical properties and their relationship to ore minerals reflect the interplay of primary and secondary processes. 90 Table 4.1: Comparison of the geological and geophysical properties of kimberlite and magmatic sulfide deposits, using the Anuri kimberlite and the Kabanga massive sulfide deposit as respective examples. Geologic feature Kimberlite e.g. Anuri Magmatic Sulfide e.g. Kabanga Ore Diamond Nickel in pentlandite, copper in chalcopyrite, platinum group elements. Geological environment Cratons Variable but typically rift zones Formational processes Intrusion, typically with extrusive component (Anuri) Intrusion, either crystallizes intrusively (Kabanga) or extrusively Host rock Ultramafic kimberlite Layered ultramafic-mafic complex Country rock Variable but commonly metagranite or sedimentary rocks Variable, but typically sedimentary rocks that provide sulfur for immiscible sulfide melt Secondary processes Serpentinization, surficial weathering (producing clay), typically pervasive Serpentinization, surficial weathering Magnetic expression Variable, dependent on host rock and kimberlite facies. Complicated by remanence. Mineralization typically occurs as magnetic highs. Ultramafic complex also occur as magnetic highs once altered. Complicated by remanence Gravity expression Typically occurs as gravity low due to alteration Fresh ultramafic rocks and mineralization occur as dense bodies. Altered ultramafic rocks can occur as lows Primary geological processes are very different for kimberlite and magmatic sulfides, principally due to differences in magma chemistry, geologic environment, volatile content, and magma volumes. Both deposit types can be predominantly intrusive or extrusive, and the deposits chosen for study represent one of each of these emplacement styles; the Anuri kimberlite is an extrusive crater facies-dominated kimberlite whereas Kabanga is an intrusive magmatic sulfide deposit. Despite differences in emplacement styles, the geologic processes occurring in both extrusive kimberlite pipes and intrusive magmatic sulfide complexes have similar effects on physical property - mineralogy relationships, though different physical properties ranges may exist for the individual deposit types. Eruption dynamics in the extrusive kimberlite environment cause sorting of dense and magnetic oxide minerals together with diamonds. In the intrusive magmatic environment, dense ore minerals sink to the base of the magma conduit, forming massive sulfide dominated by magnetic pyrrhotite. Both primary , 91 processes tend to concentrate ore minerals with dense magnetic minerals, causing common physical property - mineralogy relationships for unaltered occurrences of both deposit types. Ultramafic rocks, comprising both kimberlite and layered complexes hosting magmatic sulfide deposits, are commonly subject to secondary alteration processes including serpentinization. Serpentinization produces magnetite, which dramatically increases the susceptibility of ultramafic rocks. Susceptibility anomalies associated with serpentinized ultramafic rocks tend to overshadow those associated with ilmenite/chromite concentrations in sorted kimberlite pipes or massive pyrrhotite in magmatic sulfide deposits. Therefore, anomalies associated with ore become significantly less evident in susceptibility models. High susceptibility anomalies are consequently not necessarily suggestive of mineralization but instead may indicate serpentinized ultramafic rocks. Furthermore, high susceptibilities in kimberlite, resulting from secondary magnetite, may signify resorption of diamonds, as the oxidizing environment required to produce magnetite are corrosive towards diamonds (Fedortchuk et al., 2004). High susceptibility may also falsely indicate ore in magmatic sulfide environments, as magnetite may replace sulfide minerals. Serpentinization decreases density by replacing ferromagnesian minerals in the ultramafic rocks with less dense serpentine. As density of the host kimberlite or ultramafic complex is reduced during serpentinization, anomalies associated with concentrations of ore minerals (diamond and associated oxide minerals or sulfide minerals) hosted by these ultramafic rocks become more obvious. However, disseminated ore (both sulfide minerals and diamonds) can potentially be masked within highly serpentinized rocks, as opposing density effects of dense ore mineral concentrations and serpentinization cancel to eliminate any density anomalies. In order to locate ore zones within pervasively serpentinized rocks, density models need to be interpreted in conjunction with other physical property models, such as susceptibility, conductivity or chargeability models. Based on the analysis of the effects of primary and secondary geological processes on physical properties in both kimberlite and magmatic sulfide environments, relationships can be established between mineralogy and physical properties. In the Anuri kimberlite, magnetic susceptibility is primarily a function of magnetite produced during serpentinization or contained within crustal xenoliths. The addition of magnetite-bearing crustal xenoliths to a kimberlite causes dilution of the diamond grade. As such, susceptibility is inversely related to diamond grade. Upper susceptibility cutoffs can be characterized for high-grade rocks, on a deposit-specific basis. For the Anuri kimberlite, high-grade rocks (> 150 stones/100 kg) appear to have 92 susceptibilities less than 10 x 10"3 SI. Similarly, density can be directly related to ore in crater facies kimberlite pipes. Sedimentary processes, including airfall and resedimentation, concentrate diamonds with other dense minerals, such that volcaniclastic kimberlite breccia rocks rich in diamonds tend to be denser. High-grade rocks within the Anuri kimberlite consequently have a characteristic range of densities (2.42-2.51 g/cm3). In summary, relationships between density, susceptibility and diamond grade occur as a result of primary and secondary processes. These relationships potentially allow for high-grade rocks to be identified based on a combination of density and susceptibility values. Because of commonalities in primary and secondary geological processes in all crater facies kimberlite pipes, relationships between mineralogy and physical properties discussed in this thesis are likely applicable to other crater facies-dominated kimberlite pipes. In magmatic sulfide deposits, the relationship between physical properties and ore minerals is more straightforward. Not only do dense sulfide ore minerals (particularly pentlandite and chalcopyrite) contribute directly to density anomalies, they also occur with significant quantities of dense pyrrhotite that may also be magnetic depending on the polytype. Therefore, in this deposit environment, physical properties can be quantifiably related to sulfide mineral abundances. Mineral contents were accurately calculated for mafic-ultramafic and mineralized rocks at Kabanga, using the Mineral Prediction Filter (Williams and Dipple, 2005). Although this program was developed for the Perseverance extrusive magmatic sulfide deposit, it was demonstrated to accurately calculate pre mineral abundances for the Kabanga intrusive magmatic sulfide deposit. As such, the Mineral Prediction Filter in specific, and quantitative relationships between physical properties and ore mineralogy in general, are widely applicable for a range magmatic sulfide deposits, due to similarities in rock type and mineralization. Primary and secondary geologic processes occurring in both kimberlite and magmatic sulfide deposits, and their effects on both physical properties and mineralogy, are likely common to other ultramafic rock-hosted mineral deposits (Table 4.2), because of similarities in host rock mineralogy. Host rocks and geologic processes of diamondiferous kimberlite/lamproites, and sapphire and ruby-bearing alkali basalts/lamprophyres are relatively comparable (Table 4.2). Therefore, relationships between physical properties and mineralogy resulting from primary and secondary processes established in this thesis should be consistent for extrusive forms of these deposit types. Similarly, magmatic sulfide, magmatic oxide, Alaskan-type intrusions, and chromite deposits are commonly hosted by mafic (anorthosite, diabase, gabbro/basalt) to ultramafic (komatiite, peridotite, dunite, pyroxenite) rocks. Not only do these host rocks have 93 similar physical properties (high densities, moderate susceptibilities), but relationships between physical properties and ore minerals created by primary geological processes are similar (i.e. accumulation of dense minerals at the base of intrusion upon crystallization and settling under density). Ultramafic host rocks for magmatic sulfide, magmatic oxide, Alaskan-type intrusions, and chromite deposits are also prone to serpentinization. In summary, physical property -mineralogy correlations discussed in this thesis are likely applicable to other ultramafic rock-hosted mineral deposits. 94 Table 4.2: Comparison of geological and geophysical properties of different mafic-ultramafic rock-hosted mineral deposits where the ore mineral is syngenetic. Mineral Deposit Example Host rock Ore Form of Alteration Gravity Magnetics minerals mineralization Diamondiferous Anuri, Kimberlite Diamond Discrete grains Serpentinization Gravity lows Magnetic Kimberlites Ekati and (ultramafic, randomly due to expressions Diavik ultrabasic) distributed within Weathering to weathering and are highly (Canada) grading from kimberlite clays (Gerryts, serpentinization variable, hypabyssal diatremes and 1967; Pell, (Hoover et al., depending on Orapa intrusions to potentially 1999a) 1992, da kimberlite (Botswana) diatreme enriched in Costa, 1989; chemistry, breccias near crater-facies due Gerryts, 1967; facies, host Kimberley surface and to winnowing of Macnae, 1979) rock Premier pyroclastic fines (Pell, or highs from magnetism (South rocks in the 1999a) fresh kimberlite (Pell, 1999a; Africa) crater facies at surface (Pell, Gerryts, 1967). 1999a) Diamondiferous Argyle (Aus.) Lamproite Diamond, Discrete grains Alteration to talc, Gravity low due Magnetic Lamproite (ultrapotassic restricted to that are sparsely carbonate and to weathering expressions mafic rocks pyroclastic and randomly sulfide or and vary from characterized rocks and distributed in serpentine, serpentinization magnetic lows by olivine, dikes matrix of chlorite and (Hoover etal., in crater facies leucite, (Pell, lamproite and magnetite (Pell, 1992) lamproite (Pell, richterite, 1999b) some mantle 1999b; Jacques 1999b) to weak diopside or xenoliths (Pell, etal., 1986) magnetic highs sanidine) 1999b) (Astro Diamond (Pell, 1999b) Weathering to Mines, 2005) clay (Pell, 1999b) Mineral Deposit Example Host rock Ore minerals Form of mineralization Alteration Gravity Magnetics Mafic- Mark Alkali basalts Sapphire Xenocrysts in Clay altered and Intrusions Delimit host ultramafic- diatreme and lamprophyre and ruby hypabyssal (highest ferruginized due likely occur as rocks assuming hosted (BC) as lava flows, grade) or eruptive to weathering gravity highs if good contrast sapphire hypabyssal rocks (Simandl and (most altered fresh and with and ruby Yogo intrusions and Paradis, 1999) are highest gravity lows if surrounding (Montana) volcaniclastic grade) (Simandl pervasively lithologies rocks (Simandl and Paradis, altered. (Simandl and Braemer and Paradis, 1999) Paradis, 1999) (Aus.) 1999) Magmatic Kabanga Layered mafic- Ni, Cu, Massive sulfide at Serpentinization Gravity data Magnetic data sulfides (Tanzania), ultramafic within base of and surficial highlights detects layered Voisey's intrusion or flood sulfide intrusion/flow, and weathering. dense sulfide mafic-Bay and basalt/komatiite minerals, disseminated bodies ultramafic Thompson PGM sulfide in basal (Paterson, intrusion and (Canada) ultramafic rocks 1970; mineralization Noril'sk Dowsett, (Gunn and (Russia), 1970) Dentith, 1997; Kambalda Dowsett, 1967) (Aus.) Alaskan- Tulameen Ultramafic Pt, (Os, Cumulus and Serpentinization May be Primarily used type (BC), intrusive Rh, Ir, intercumulus during regional important (Nixon, 1996) Red complexes, magnetite) chromite within 1) metamorphism, (Nixon, 1996) for identification Mountain commonly zoned as PGM disrupted chromitite (Nixon, 1996) for identifying of chromite and (Alaska), (dunite, wehrlite, (Nixon, layers in dunite, 2) fresh magnetite-rich Ural clinopyroxenite, 1996) thick magnetite ultramafic layers Mountains gabbro) (Nixon, beds, 3) lenses and complexes or (Russia) 1996) , veins in accumulations clinopyroxenite of chromite (Nixon, 1996) as Mineral Example Host rock Deposit Ore Form of Alteration minerals mineralization Gravity Magnetics Magmatic Methuen Massive, Fe-Ti-V Massive, Not typically Massive and Magnetic response, oxide (Ontario), Lac- layered, zoned within disseminated, altered (Gross et disseminated may be subdued or deposits du-Pin-Rouge mafic intrusion ilmenite, Ti- locally in layers al., 1999) oxide minerals strongly negative if (Quebec), (anorthosite, magnetite, occur as dense deposit is ilmenite-felines norite, gabbro, magnetite. anomalies in rich (Gross et al., (Norway) etc.; Gross et Associated gravity data. 1999) al., 1999) with Hosting intrusion sulfides likely also (Gross et positive gravity al., 1999) anomaly. Stratiform Bushveld Layered Chromite, Chromite-rich Layered intrusion Magnetic data can chromite (South Africa), intrusions PGE, layers potentially Gravity data highlight orientation Great Dyke magnetite serpentinized or required to assist of lithological (Zimbabwe) weathered due to magnetic data layering and mafic-ultramafic (Guhn and locates intrusive mineral content Dentith, 1997; pipes (Buchanan, Ash,1996)and 1988) can accurately Podiform Josephine Variably Chromite Chromite-rich Variable predict chromite Chromite not chromite ophiolite serpentinized pods, lenses, serpentinization, content (Yungal, directly detectable, (Oregon), peridotite layers no noticeable 1956) for both but associated Coto intrusions (e.g. affects from stratiform and serpentinite is (Philipines), ophiolite; Ash, surface oxidation podiform noticeable Elazig 1996) (Ash, 1996) chromite (Klichnikov and (Turkey) Segalovich, 1967) 4.2 Implications for Geophysical Inversions This thesis aimed to understand the relationship between physical properties and primary and secondary mineralogy of ultramafic rock-hosted mineral deposits. These relationships must be clearly understood in order for physical property volumes produced by inversions to be meaningfully interpreted. Physical property - mineralogy relationships developed in this thesis are discussed in the following section with respect to interpretation of geophysical data and physical property models for rock types, alteration and potential ore content. 4.2.1 Kimberlite: Anuri Case Study Three-dimensional physical property models produced by inversion of geophysical data greatly assist exploration for kimberlite. These models can be used to define the location and spatial extent of kimberlite pipes, identify rock types within the pipe and assess diamond potential, based on relationships between physical properties and diamond established previously in this thesis. An optimal scenario would involve inverting geophysical data from the Anuri kimberlite to produce physical property models that could be interpreted with respect to rock type or diamond grade, effectively testing relationships developed in Chapter 2. Unfortunately, raw geophysical data over the Anuri kimberlite was unavailable, precluding creation and interpretation of three dimensional physical property models of the kimberlite. However, conjectural statements can be made based on physical property contrasts between the country rock and kimberlite. The Anuri kimberlite manifests in magnetic data as a break in a magnetic diabase dyke but the kimberlite itself lacks a magnetic signature relative to the granitic host rocks (Figure 2.3 A). The lack of magnetic signature for the kimberlite reflects that there is little susceptibility contrast between the granite and volcaniclastic kimberlite breccia, the dominant kimberlite lithology, whereas the diabase is much more magnetic (Table 4.3). Hypabyssal kimberlite is moderately magnetic, but because of its small volume and depth in the pipe (-290 m), it does not contribute significantly to the magnetic signature of the Anuri kimberlite. Clearly, magnetic susceptibility of the country rock relative to the predominant kimberlitic material is key in defining whether the kimberlite will form a magnetic anomaly. As non-magnetic kimberlite pipes, like Anuri, do not form susceptibility anomalies relative to the host rock, such kimberlites can only be located in three-dimensional magnetic susceptibility volumes as interruptions in high-susceptibility bodies. Conversely, kimberlite pipes that occur as either magnetic highs or lows could be located and spatially delineated in 98 magnetic susceptibility models. Furthermore, with sufficient data density, in-pipe variations in susceptibility models obtained from inversion of high-resolution magnetic data could be used to identify regions within the pipe with appropriate physical properties that may signify high diamond contents. Table 4.3: Summary of magnetic susceptibility statistics for the country rock and kimberlite lithologies of the Anuri kimberlite. Magnetic Susceptibility (10~3 SI) Average Standard Deviation Diabase 25.85 +78.31 -8.53 Overburden 0.50 +2.06 -0.12 Shale 0.28 +0.41 -0.18 Gneiss 1.18 +9.31 -0.15 Hypabyssal Kimberlite 11.90 +34.26 -4.14 Volcaniclastic Kimberlite Breccia 3.22 +6.53 -1.59 The density contrast between the Anuri kimberlite and granitic host rock (Figure 2.3B) implies that three-dimensional density models should resolve the spatial extents of the kimberlite. Furthermore, density variations within the pipe can be used to estimate the location of dense rocks that may contain higher diamond contents. A density model was produced from inversion of gravity data over Anuri, but the only records of this inversion are diagrams of a density model cut off at -0.15 g/cm3 density contrast (Masun et al., 2003) (Figure 4.1). The low-density contrast body likely represents the Anuri crater filled with relatively low-density volcaniclastic kimberlite breccia. Therefore, it may be possible to accurately delineate spatial extents of the kimberlite pipe by interpreting the density model. Density variations within the pipe have not been resolved, perhaps because the mesh size used in the inversion was too large (25 m) or because the gravity data was sampled on a coarse grid. In summary, there is potential within the Anuri project for establishing quantitative relationships between physical properties and mineralogy, and testing these relationships with magnetic and gravity inversions. At this stage, however, the data required to do this is not available. 99 500 625 750 875 1000 Figure 4.1: Density model using a cutoff of -0.15 g/cc density contrast. This cross-section of the density model is located along A-A' on the inset diagram of the gravity data. 4.2.3 Magmatic Sulfide Deposits: Kabanga Case Study Magnetic data for Kabanga was inverted but was difficult to interpret due to the effects of remanent magnetism. However, manifestations of massive sulfide and ultramafic rocks in magnetic data and susceptibility volumes can be discussed theoretically for fresh to pervasively serpentinized massive sulfide deposits. For unaltered ultramafic rock-hosted magmatic sulfides, the magnetic expression is dominated by anomalies associated with monoclinic pyrrhotite in the massive to disseminated sulfide. Serpentinization causes high susceptibilities in mafic-ultramafic host rocks that commonly overshadow any anomalies associated with ore. Thus, magnetic highs in these environments are not necessarily related to mineralization, and instead may signify replacement of sulfide minerals with magnetite. Similarly, gravity expressions of mineralized and ultramafic rocks can change drastically throughout the alteration history of the complex. Massive sulfide tends to occur as positive density anomalies, due to the dense ultramafic host rocks and sulfide minerals. Serpentinization replaces dense ferromagnesian minerals with low density serpentine, considerably decreasing the density of ultramafic rocks. As such, gravity expressions of altered magmatic sulfide deposits 100 tend to be dominated by dense anomalies representing mineralization with adjacent low-density bodies, representing the ultramafic complexes. To test the applicability of these predictions, gravity data was inverted and interpreted during this study. Gravity data currently available for Kabanga covers a relatively small area over the deposits, and data density is relatively sparse (Figure 3.6). Therefore, it will be difficult to resolve physical property anomalies in the subsurface with any confidence using this data. Nonetheless, several gravity inversions were performed with variable input parameters, to ascertain which features in the model do not change and therefore are required to explain the observed data. The inversion results consistently resolved a large high-density body located at the southern end of the survey, with an adjacent low-density body, which was determined to be the Kabanga Main body (Figure 4.2). Furthermore, there was a small high-density body associated with a large low-density body to the northwest, roughly at the location of the Kabanga North body. Figure 4.2: Isosurfaces of the high (greater than 0.2 g/cm3 density contrast, green to red) and low (less than -0.15 g/cm3 density contrast, blue) density bodies at Kabanga occurring in the accepted density contrast model produced by inversion of the available gravity data (Figure 3.5) using the UBC-GIF code. Exact shapes and depth extents of the dense Kabanga Main and North ore bodies and associated low-density bodies changed between individual inversions, but the location and density contrast values remained essentially constant. A comparison of high- and low-density anomalies to locations of sulfide mineralization and serpentinized ultramafic rocks from 101 drillhole, respectively, illustrates that the density anomalies discussed above roughly match up with ore bodies (Figure 4.3). Increased density of data over the ore bodies would help to additionally constrain the model. Increased data coverage might also help to resolve density variations resulting from rock type, ore content or degree of serpentinization. These density variations are not resolved in this density model, because of the gravity data's limited resolution. 102 Figure 4.3: Isosurfaces of high (red, greater than 0.2 g/cm3 density contrast) and low (blue, less than -0.15 g/cm3 density contrast) regions of density contrast model in the vicinity of Kabanga Main (A) and Kabanga North (B) ore bodies viewed from the southwest and south, respectively. Earth's surface occurs where the drilling rigs (in yellow) are displayed and the isosurfaces are cut off. Samples collected from drillholes (red lines) are overlain on the isosurfaces, as coloured disks (numbers beside disks indicates depth of sample), where colour represents the rock type: massive sulfide is red, semi-massive sulfide is orange, peridotite is dark green, pyroxenite is light green, gabbro is dark blue, diabase is light blue, metapelite is grey. 103 Chapter 5: Conclusions Interpretations of data collected during this study allowed key relationships between physical properties and mineralogy to be identified for ultramafic rock-hosted mineral deposits. Throughout the course of this study, data limitations serve to illustrate what kind of data is required for future studies, particularly with respect to proper geophysical survey design and thorough physical properly sampling of all lithologies. These lessons about data collection are put forth as recommendations to assist with future studies. Although interpretations were constrained by a lack of critical physical property and geophysical data, the objectives of this study were resolved. Additional projects required to expand on and test physical property -mineralogy relationships developed in this thesis are also recommended as further avenues of work. 5.1 Limitations of Study Extrapolation of physical property - mineralogy relationships developed in this thesis to the interpretation of geophysical inversion models was hampered by the lack of physical property and geophysical data. Large quantities of physical property data are required to confidently characterize physical properties of different rock type. For the Anuri kimberlite, physical property data was limited to magnetic susceptibility measurements for the few existing drillholes and susceptibility and density measurements made as part of this study from the one drillhole available for direct study. This precluded the formation of statistically significant relationships between physical properties, rock type and mineralogy, particularly diamond grade. However, these data limitations did serve to illustrate the amount of physical property data required to obtain meaningful results from this type of study. Geophysical data available for this study was minimal; no raw data was available for the Anuri kimberlite, and existing gravity data for the Kabanga deposit is sparse. This precluded testing of qualitative and quantitative relationships between mineralogy and physical properties developed in this study. However, these data restrictions highlighted the necessity of 1) proper survey design, in order to acquire data that will provide the required resolution of geologic features; and 2) making all raw geophysical data available for study. 5.2 Conclusions This study aimed to develop relationships between mineralogy and physical properties, particularly susceptibility and density, for ultramafic rock-hosted mineral deposits, specifically 104 crater facies-dominated kimberlites and intrusive magmatic sulfide deposits, in the context of geologic processes. The following key points illustrate how the original objectives of this study, reiterated below, were resolved using these two deposit types: 1) Characterize dense and magnetic phases present in rock types associated with two ultramafic rock-hosted mineral deposit environments. The dense and magnetic minerals within the Anuri kimberlite were determined to be predominantly ilmenite, and solid solution spinel varying in composition from chromite to magnetite. Within the Rabanga magmatic sulfide complex, dense phases were predominantly sulfide (pyrrhotite, pentlandite, chalcopyrite) and oxide minerals (magnetite, chromite). Of these, monoclinic pyrrhotite and magnetite are magnetic. 2) Understand how dense and magnetic minerals in both kimberlite and magmatic sulfide deposits relate to ore minerals of both deposits at the time offormation and throughout the history of these deposits. In the Anuri kimberlite, chromite and ilmenite predominantly occur as macrocrysts and mantle xenocrysts, which undergo the same eruptive processes as diamond. Therefore, these dense and magnetic minerals should be sorted together with diamonds. Magnetite is present as phenocrysts within the kimberlite groundmass, in crustal xenoliths and as fine grains produced by serpentinization. As magnetite is formed in relation to both primary and secondary processes, the relationship between magnetite, hence magnetism, and diamond is complex. Generally, magnetite is inversely related to diamond through resorption of diamonds in oxidizing magmatic environments and dilution of diamond content with crustal xenoliths. In the Kabanga magmatic sulfide deposit, ore minerals, including chalcopyrite and pentlandite, occur with large quantities of dense and magnetic pyrrhotite as disseminated to massive sulfide at the original base of the intrusion. Chromite occurs in insignificant amounts as cumulus grains together with olivine and pyroxene. Magnetite, produced by serpentinization, replaces ferromagnesian minerals, and chromite and sulfide minerals to a lesser extent. Magnetite is unrelated to ore content, as ore has not been remobilized on large scales during serpentinization despite replacement of sulfide minerals with magnetite. 105 3) Characterize physical property distributions of significant rock types for each deposit and explain variations and anomalous physical properties through differences in geologic processes Physical property distributions were statistically characterized for the volcaniclastic kimberlite breccia lithologies at Anuri and the mafic-ultramafic and sulfide mineral-bearing rocks at Kabanga. Density distributions tend to be normally distributed, whereas magnetic susceptibility distributions are commonly lognormally distributed. For the Anuri kimberlite, density is highest in the lithic breccia, due to the abundance of crustal xenoliths, which are denser than the altered kimberlite material. Addition of crustal xenoliths dilutes the diamond content. As such, density and diamond content are inversely related for the lithic breccia. Heterolithic volcaniclastic kimberlite breccia is the least dense, perhaps due to pervasive serpentinization and small amounts of mantle xenocrysts. Autolithic volcaniclastic kimberlite breccia is moderately dense because of large amounts of mantle-derived constituents. Consequently, density tends to be directly related to diamond content for the volcaniclastic kimberlite breccias. Susceptibility is highest in the lithic breccia and heterolithic volcaniclastic kimberlite breccia, in which magnetite-bearing crustal xenoliths are most abundant. As such, susceptibility is inversely related to diamond content. For the Kabanga magmatic sulfide deposit, density is highest in the sulfide mineral-bearing rocks (disseminated to massive sulfide) and lowest in ultramafic rocks, due to serpentinization. Mafic rocks have moderate densities because they are not strongly altered. Therefore, density is a function of two opposing processes, sulfide mineralization, which increases density and serpentinization, which decreases density. Susceptibility is lowest in metasedimentary and mafic rocks, as these rocks lack significant amounts of sulfide and oxide minerals. Massive sulfide has moderately high susceptibilities due to the presence of abundant magnetic monoclinic pyrrhotite. Ultramafic rocks are highly susceptible because they contain magnetite produced by serpentinization. Semi-massive sulfide has.the highest susceptibilities , because of abundant monoclinic pyrrhotite and magnetite. Consequently, susceptibility also appears to be a function of both sulfide mineralization and serpentinization. 4) Develop a method of identifying high-grade samples based on physical properties, by establishing how geological processes concentrate ore minerals with dense and magnetic minerals. 106 Rocks within the Anuri kimberlite with high diamond contents tend to have a restricted range of susceptibilities and densities; rocks with greater than 150 stones/100 kg have susceptibilities less than 10 x 10"3 SI and densities of 2.42-2.51 g/cm3 (Figure 2.17). Though these physical property values may not signify rocks with high diamond contents in all kimberlite pipes, the general principles will apply: kimberlite with abundant diamonds would have moderately high densities, due to accumulation of mantle material, and low susceptibilities, implying low abundances of crustal xenoliths to dilute the diamond grade and non-oxidizing conditions during emplacement. Ore mineral abundances can be accurately quantified for mafic-ultramafic rocks at Kabanga, and other magmatic sulfide deposits, using the Mineral Prediction Filter (Williams and Dipple, 2005). However, caution must be exercised when using this program to calculate sulfide mineral abundances in highly serpentinized samples. Preliminary modeling indicates that pervasively serpentinized rocks can contain up to 50% sulfide minerals and have a density equivalent to that of a barren mafic or ultramafic rock. In order to identify mineralized serpentinized rocks, density data must be interpreted in conjunction with other physical property data, including susceptibility or conductivity, which would have anomalous values associated with sulfide mineral-rich rocks. 5) Apply physical property — mineralogy relationships to the improvement of inversions and interpretation of physical property models; Physical property models can be interpreted with respect to ore mineralogy by applying relationships developed in this study. Physical property - mineralogy relationships developed in this study could not be tested due to limited data, but can be discussed theoretically. Generally, kimberlite pipes occur in density models as low-density bodies, as they are commonly serpentinized and weathered. Density models thus can be used to delineate the spatial extent of a kimberlite pipe. Density variations within a crater facies-dominated pipe may be further interpreted to represent graded units, with moderate- to high-density beds being those with the greatest amount of mantle-derived material, including diamonds. Magnetic expressions of kimberlite pipes are highly variable, depending on a kimberlite's magnetism relative to that of the country rocks. As such, kimberlite pipes may occur as positive or negative anomalies in susceptibility volumes, or may not appear at all if there is no susceptibility contrast with the country rock. Moreover, susceptibility models of kimberlite pipes may be complicated by remanent magnetism. If there is a susceptibility contrast between a kimberlite and the country 107 rocks and remanence is not a problem, then susceptibility variations within the pipe may be used to infer potential diamond content. Susceptibility is inversely related to diamond content, due to grade dilution with magnetite-bearing crustal xenoliths and potentially because of resorption of diamond in oxidizing magmas that crystallize magnetite. As the Mineral Prediction Filter was demonstrated to accurately calculate ore mineral abundances for magmatic sulfide deposits, density and susceptibility models could be used to calculate three-dimensional models of ore mineral abundances. Qualitatively, physical property models can be used to infer rock type. In unaltered deposits, density anomalies will be associated with both mafic-ultramafic host rocks and accumulations of sulfide minerals, whereas susceptibility anomalies will be solely related to concentrations of monoclinic pyrrhotite in massive sulfide. Serpentinization causes mafic-ultramafic rocks to occur as low density and high susceptibility anomalies. High-density anomalies associated with sulfide mineralization become more obvious but moderate susceptibility anomalies related to massive sulfide may be masked by high susceptibilities of the serpentinized mafic-ultramafic complex. Furthermore, remanent magnetism can present serious complications for meaningful interpretation of magnetic data and susceptibility models. 6) Synthesize learnings from both deposits studied in this thesis and extrapolate to other ultramafic-hosted mineral deposits. Primary and secondary geologic processes appear to have a similar effect on physical property - mineralogy relationships in both the Anuri kimberlite and the Kabanga magmatic sulfide deposits. These deposits can be considered representative of crater facies-dominated kimberlite and intrusive/extrusive magmatic sulfide deposits, due to commonalities in country rock and geologic processes. Primary processes, either pyroclastic eruption or segregation, gravity settling and crystallization of a sulfide melt, tend to concentrate ore minerals with dense and magnetic minerals at the base of graded beds or intrusion conduits for kimberlite pipes and magmatic sulfide deposits, respectively. Secondary serpentinization causes density of ultramafic rocks to decrease, due to replacement of dense ferromagnesian minerals with serpentine, and susceptibility to increase, as magnetite is produced during serpentinization. Serpentinization in both deposit types does not have a significant effect on ore. Effects of geologic processes on physical properties are thus similar for crater facies-dominated kimberlite pipes and intrusive magmatic sulfide deposits. Similarly, physical property - mineralogy relationships resulting from primary and secondary geologic processes observed in these deposits may be applicable for 108 other ultramafic-rock hosted mineral deposits ranging from diamondiferous lamproites and gemstones hosted by mafic-ultramafic rocks to magmatic oxide and chromite deposits (Table 4.2). 5.3 'Recommendations for Future Work There are still many avenues of research that would greatly assist the exploration industry's understanding of physical property - mineralogy relationships related to the effects of primary and secondary geologic processes. This study has highlighted some key issues that should be considered for future work: • Both magnetic and gravity data should be consistently acquired over ultramafic rock-hosted mineral deposits. This has been recently made easier with the advent of effective airborne gravity methods. Combined interpretation of susceptibility and density models allows for more comprehensive and accurate interpretation of physical properties with respect to geologic features, including mineralogy. • Geophysical surveys should be designed to provide adequate coverage of both the deposits of interest and the surrounding country rocks, in case more mineral showings in the nearby vicinity are discovered. Surveys should also be designed to provide the resolution desired for physical property models; data needs to be collected on scales less than or equal to the scale of geological features (e.g. thicknesses of rock units and alteration halos), in order to resolve features of interest, including rock unit contacts, graded units and lenses of ore minerals. • Physical property data should be collected for all lithologies and degrees of alteration of those lithologies, in order to determine the statistically significant physical property characteristics of each lithology. As such, physical property data could be interpreted confidently with respect to rock type. • The relationship between dense and magnetic minerals and diamonds in kimberlite requires further defining. The process used to quantify dense and magnetic mineral phases in the Anuri pipe may have been biased as 1) only medium size grains were analyzed, while most magnetite may be fine grained, and 2) proportions of magnetic oxide phases were quantified after the magnetic oxide phase analysis, so material may have been lost. 109 In the magmatic sulfide environment, discrepancies between mineral abundances calculated by the Mineral Prediction Filter and observed in the petrographic analysis have yet to be fully resolved. Underestimation of pyrrhotite and magnetite content may be related to demagnetization effects, but further work is required to ascertain whether demagnetization is truly the cause and if its effects can be accounted for. Furthermore, pentlandite is consistently overestimated for the Kabanga samples; this must be accommodated for when assessing the results. Lastly, there are unresolved issues of accurately predicting sulfide mineral abundance in serpentinized rocks. Incorporation of susceptibility data should resolve this problem, as serpentinized samples will be highly susceptible despite having densities typical of barren rocks. Nonetheless, the effectiveness of susceptibility and density for identifying sulfide mineral-bearing serpentinized rocks needs to thoroughly tested for several deposits that exhibit variable degrees of serpentinization to ensure that the Mineral Prediction Filter can accurately predict sulfide contents in serpentinized rocks. Physical property - mineralogy relationships for diatreme and hypabyssal facies-dominated kimberlite pipes need to be characterized using a similar methodology as the one developed in this study. 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Identifying sulfide mineralization from physical property measurements and its application to mineral exploration inversions. Geological Society of America Abstracts with Programs, v. 37, i . 7, p. 23. Williams, N.C. (2006). A new exploration framework for mapping and refining exploration targets using inversions. MDRU-GIF Annual Meeting, Toronto, March 9, 2006. Wolfgram, P. and Golden, H . (2001). Airborne E M applied to sulfide nickel-examples and analysis. Exploration Geophysics, v. 32, p. 136-140. Wyatt, B.A. , Baumgartner, M . , Anckar, E., and Grutter, H . (2004). Compositional classification of "kimberlitic" and "non-kimberlitic" ilmenite. Lithos, v. 77, p. 819-840. Yungal, S. (1956). Prospecting for chromite with gravimeter and magnetometer over rugged topography in east Turkey. Geophysics, v. 21, i . 2, p. 433-454. 116 Appendix A; Magnetic Susceptibility and Diamond Grade Data for All Drillholes Data displayed in the following tables were provided by Kennecott Exploration. Lithological abbreviations are as follows: V K B = (heterolithic) volcaniclastic kimberlite breccia; M V K B = autolithic (magmaclast-rich) volcaniclastic kimberlite breccia; F V K B = fine-grained volcaniclastic kimberlite breccia; L V K B B = lithic (volcaniclastic kimberlite breccia) breccia. Table A . l : Magnetic susceptibility and diamond content measurements for LT508-05 drillhole. Drillhole Average Depth (m) Average Susceptibility (10"3 SI) Stones/ 100kg Macrocryst: mic rocryst Lithology 02LT508-05 42.30 2.59 341.5 0.03 MVKB 02LT508-05 55.15 3.24 210.8 0.05 MVKB 02LT508-05 59.75 3.26 297.2 0.04 MVKB 02LT508-05 75.50 4.55 116.6 0.10 FVKBA/KB 02LT508-05 91.20 3.37 212.3 0.11 FVKB/VKB 02LT508-05 95.25 3.95 144.2 0.07 FVKBA/KB 02LT508-05 103.90 7.76 214.9 0.11 FVKBA/KB 02LT508-05 108.30 6.16 87.3 0.29 VKB 02LT508-05 117.40 3.01 57.2 0.20 VKB 02LT508-05 122.20 4.59 132.4 0.18 VKB 02LT508-05 126.35 3.55 74.8 0.17 VKB 02LT508-05 148.35 5.60 175.1 0.12 VKB 02LT508-05 196.50 4.45 46.7 0.25 VKB 02LT508-05 201.35 4.24 136.3 0.14 VKB Table A.2: Magnetic susceptibility and diamond content measurements for LT508-03 drillhole. Drillhole Average Average Stones/ Macrocryst:mic Lithology Depth (m) Susceptibility 100kg rocryst (10 3 SI) 01LT508-03 211.00 2.80 180.0 0.13 VKB 01LT508-03 215.65 3.03 157.9 0.07 VKB 01LT508-03 220.30 3.94 210.0 0.11 VKB 01LT508-03 224.80 2.73 230.0 0.10 VKB 01LT508-03 229.15 2.49 179.0 0.13 VKB 01LT508-03 233.65 1.97 205.9 0.05 VKB 01LT508-03 242.98 2.53 126.3 0.09 VKB 01LT508-03 247.88 3.62 240.0 0.26 VKB 01LT508-03 252.68 3.32 305.3 0.04 VKB 01LT508-03 261.86 2.67 160.0 0.14 VKB 01LT508-03 271.40 4.63 200.0 0.05 VKB 01LT508-03 285.00 4.38 81.6 0.13 VKB 01LT508-03 289.65 5.50 160.0 0.07 VKB 01LT508-03 322.51 1.92 80.8 0.33 VKB 117 Table A.3: Magnetic susceptibility and diamond content measurements for LT508-01 drillhole. Drillhole Average Depth (m) Average Susceptibility (103 SI) Stones/ 100kg Macrocryst:mic rocryst Lithology LT508-01 253.50 5.75 110.0 0.10 MVKB LT508-01 248.50 6.11 68.6 0.17 MVKB LT508-01 236.00 6.12 104.8 0.10 MVKB LT508-01 231.00 4.04 215.7 0.05 MVKB LT508-01 227.00 6.17 250.0 0.04 MVKB LT508-01 212.50 10.22 137.2 0.27 MVKB LT508-01 208.00 9.77 126.2 0.08 MVKB LT508-01 204.00 11.32 120.0 0.09 MVKB LT508-01 199.00 4.94 95.2 0.11 MVKB LT508-01 188.00 3.78 160.4 0.13 MVKB LT508-01 178.50 4.43 140.0 0.17 VKB LT508-01 174.00 4.79 147.1 0.07 VKB LT508-01 169.50 4.15 134.6 0.08 VKB LT508-01 146.00 9.31 84.2 0.14 VKB LT508-01 141.50 8.80 157.4 0.21 VKB LT508-01 136.50 5.82 303.9 0.15 VKB LT508-01 131.50 6.15 165.0 0.14 VKB LT508-01 127.00 3.75 183.7 0.06 VKB LT508-01 117.50 4.44 226.8 0.05 VKB LT508-01 113.00 5.51 173.9 0.07 VKB LT508-01 108.00 5.91 92.8 0.13 VKB LT508-01 102.50 3.10 230.0 0.05 VKB LT508-01 97.50 2.47 130.0 0.08 VKB LT508-01 92.50 2.28 200.0 0.05 VKB LT508-01 87.50 2.93 170.0 0.06 LVKBB LT508-01 82.50 2.95 172.0 0.60 LVKBB LT508-01 77.50 2.52 228.3 0.05 LVKBB Table A.4: Magnetic susceptibility and diamond content measurements for LT508-08 drillhole. Drillhole Average Depth (m) Average Susceptibility (10'3 SI) Stones/ 100kg Macrocryst:mic rocryst Lithology 02LT508-08 143.05 4.84 40.3 1.00 FVKB 02LT508-08 133.80 6.19 61.5 0.20 FVKB 02LT508-08 128.70 3.65 50.2 0.25 FVKB 02LT508-08 123.15 5.33 41.6 0.33 FVKB 02LT508-08 117.70 5.34 81.7 0.14 FVKB 02LT508-08 107.20 5.54 41.3 0.33 FVKB 02LT508-08 101.75 6.29 69.2 0.50 FVKB 02LT508-08 96.40 5.84 81.0 0.25 VKB 02LT508-08 91.10 5.03 59.9 0.20 VKB 02LT508-08 86.10 6.90 60.1 0.20 VKB 02LT508-08 81.25 8.70 56.7 0.29 VKB 02LT508-08 76.65 10.30 60.0 0.50 VKB 02LT508-08 58.25 4.54 66.7 0.17 VKB 118 Appendix B: Compositional analysis of ilmenite grains within the Anuri kimberlite Samples from six intervals along the LT508-1 drillhole of the Anuri kimberlite were chosen for magnetic phases analysis, including a high and low susceptibility region from the autolithic volcaniclastic kimberlite breccia, heterolithic volcaniclastic kimberlite breccia, and lithic breccia. These six samples were crushed and dense separates were removed using a Wilfley Table. Magnetic grains were removed from the separates, and a Franz separator was used to remove moderately magnetic grains. Grains separated from the six samples using a magnet (M) and the Franz separator (F) were analyzed on the electron microprobe, using a chromite standard (Table B . l ) . 50 grains from each separate of each of the six samples was analyzed and classified as ilmenite i f they contained over 40% Ti02. Analyses were discarded i f they yielded totals less than 97%. Table B. l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for ilmenite grains separated from samples of the Anuri kimberlite l 8 . Sample MgO A l 2 O s Si0 2 CaO T i 0 2 MnO Fe2Oj NiO Nb 2 O s Totals 108F 8.35 0.36 0.06 0.02 46.28 0.30 0.24 41.85 0.10 0.06 0.00 97.63 108F 8.37 0.32 0.01 0.00 46.53 0.27 0.11 41.99 0.11 0.00 0.00 97.69 108F 9.00 0.51 0.05 0.00 46.32 1.35 0.18 40.24 0.07 0.00 0.00 97.73 108F 8.12 0.33 0.04 0.01 46.06 0.36 0.21 42.61 0.06 0.01 0.00 97.81 108F 8.11 0.44 0.04 0.01 45.94 0.54 0.20 42.45 0.10 0.00 0.00 97.83 108F 8.72 0.33 0.02 0.04 47.40 0.28 0.26 40.70 0.07 0.03 0.00 97.87 108F 8.77 0.41 0.03 0.01 47.09 0.50 0.17 40.82 0.11 0.02 0.00 97.93 108F 8.74 0.41 0.03 0.03 47.08 0.79 0.17 40.74 0.01 0.00 0.02 98.02 108F 8.85 0.40 0.04 0.01 .47.47 0.30 0.25 40.71 0.00 0.00 0.00 98.03 108F 8.39 0.37 0.02 0.00 46.32 0.19 0.22 .42.54 0.08 0.00 0.00 98.13 108F 8.64 0.48 0.07 0.01 46.72 1.18 0.20 40.76 0.10 0.10 0.00 98.27 108F 8.35 0.33 0.03 0.02 46.75 0.18 0.21 42.39 0.06 0.00 0.00 98.33 108F 9.61 0.36 0.05 0.00 47.98 1.10 0.17 38.88 0.13 0.05 0.01 98.36 108F 8.74 0.37 0.07 0.03 46.90 0.21 0.26 41.67 0.06 0.06 0.00 98.36 108F 10.00 0.36 0.03 0.03 47.97 0.27 0.27 39.23 0.13 0.09 0.00 98.38 108F 8.98 0.38 0.06 0.04 47.15 0.44 0.22 41.00 0.12 0.00 0.00 98.38 108F 8.65 0.34 0.04 0.01 46.86 0.40 0.20 41.61 0.12 0.12 0.02 98.38 108F 8.63 0.29 0.03 0.01 46.65 0.29 0.19 42.17 0.04 0.19 0.00 98.48 108F 8.80 0.37 0.07 0.01 47.25 0.73 0.29 40.84 0.10 0.06 0.00 98.51 108F 8.49 0.43 0.05 0.00 46.53 0.48 0.23 42.32 0.01 0.00 0.00 98.54 108F 8.98 0.40 0.06 0.02 47.31 1.19 0.21 40.20 0.15 0.03 0.00 98.55 108F 9.35 0.48 0.03 0.01 47.21 1.11 0.24 39.96 0.18 0.00 0.00 98.57 108F 8.96 0.42 0.05 0.00 47.10 0.40 0.17 41.52 0.02 0.00 0.00 98.65 108F 9.50 0.43 0.06 0.02 48.10 0.26 0.31 39.93 0.07 0.00 0.00 98.68 108F 8.56 0.36 0.02 0.01 46.27 0.30 0.26 42.66 0.05 0.20 0.00 98.68 108F 8.52 0.36 0.04 0.04 46.53 0.22 0.20 42.70 0.11 0.00 0.00 98.72 108F 8.88 0.40 0.04 0.00 47.57 0.64 0.22 40.72 0.10 0.15 0.00 98.72 108F 9.22 0.32 0.08 0.01 47.39 0.67 0.24 40.57 0.15 0.08 0.00 98.73 108F 8.55 0.46 0.02 0.04 46.62 0.42 0.11 42.52 0.02 0.00 0.00 98.75 108F 8.44 0.43 0.09 0.01 46.40 0.64 0.18 42.38 0.08 0.11 0.00 98.77 108F 8.48 0.38 0.03 0.00 47.11 0.22 0.26 42.08 0.08 0.10 0.06 98.80 108F 9.12 0.35 0.05 0.02 47.21 0.31 0.16 41.41 0.07 . 0.08 0.02 98.80 108F 9.18 0.36 0.04 0.02 47.15 0.48 0.19 41.12 0.12 0.18 0.04 98.87 ' 108F 8.93 0.38 0.02 0.02 46.80 0.48 0.25 41.72 0.08 0.22 0.01 98.92 108F 8.38 0.39 0.03 0.04 46.94 0.36 0.19 42.51 0.06 0.06 0.00 98.96 108F 8.37 0.42 0.06 0.00 46.49 0.69 0.21 42.55 0.19 0.00 0.00 98.98 119 Sample MgO Si0 2 CaO T i 0 2 C r 2 0 ? MnO Fe 20, NiO Nb 2 O s T a 2 O s Totals 108F 8.70 0.40 0.01 0.00 46.08 0.38 0.28 43.09 0.04 0.00 0.00 98.99 108F 9.21 0.41 0.06 0.00 47.69 0.29 0.21 41.05 0.07 0.03 0.00 99.02 108F 9.03 0.37 0.06 0.02 47.37 1.34 0.21 40.50 0.10 0.06 0.00 99.05 108F 9.07 0.47 0.04 0.00 47.25 0.44 0.13 41.60 0.16 0.00 0.00 99.17 108F 11.00 0.50 0.06 0.03 50.41 2.05 0.22 34.70 0.18 0.00 0.02 99.17 108F 10.18 0.21 0.03 0.03 51.09 0.24 0.32 36.96 0.12 0.00 0.01 99.18 108F 8.79 0.37 0.09 0.03 47.25 0.51 0.20 41.74 0.12 0.10 0.01 99.20 108F 9.45 0.47 0.07 0.02 48.11 0.35 0.17 40.58 0.03 0.00 0.00 99.24 108F 9.27 0.40 0.04 0.00 48.66 0.29 0.20 40.37 0.07 0.00 0.00 99.31 108F 9.68 0.46 0.06 0.03 49.08 0.34 0.20 39.52 0.11 0.04 0.00 99.53 108F 0.12 0.00 0.01 0.02 49.93 0.00 1.73 48.17 0.03 0.00 0.00 100.00 108M 8.36 0.45 0.10 0.04 45.07 0.43 0.21 41.42 0.05 0.18 0.00 96.30 108M 6.90 0.42 0.05 0.00 43.45 0.10 0.18 45.31 0.08 0.00 0.00 96.49 108M 8.09 0.40 0.03 0.07 45.10 0.40 0.18 42.12 0.13 0.00 0.07 96.58 108M 8.97 0.36 0.04 0.04 46.80 0.30 0.20 39.74 0.07 0.10 0.00 96.63 108M 8.00 0.36 0.02 0.00 45.30 0.36 0.20 42.28 0.15 0.06 0.00 96.72 108M 9.17 0.44 0.04 0.04 46.27 1.08 0.16 39.45 0.16 0.03 0.00 96.84 108M 8.52 0.37 0.05 0.02 46.46 0.44 0.23 40.90 0.18 0.10 0.00 97.28 108M 9.30 0.40 0.04 0.00 47.20 0.58 0.17 39.40 0.12 0.08 0.00 97.29 108M 8.69 0.36 0.01 0.06 46.28 0.39 0.18 41.28 0.11 0.00 0.01 97.36 108M 8.04 0.39 0.06 0.05 45.18 0.27 0.19 42.99 0.10 0.10 0.00 97.37 108M 9.10 0.45 0.02 0.00 46.61 0.49 0.25 40.35 0.10 0.00 0.00 97.37 108M 8.39 0.47 0.08 0.07 45.74 0.49 0.22 41.86 0.06 0.04 0.00 97.42 108M 10.29 0.21 0.04 0.05 50.15 0.64 0.33 35.57 0.16 0.01 0.00 97.45 108M 8.83 0.55 0.03 0.00 45.01 1.47 0.21 41.04 0.20 0.11 0.00 97.45 108M 0.25 0.00 0.03 0.00 49.05 0.02 1.27 46.84 0.00 0.00 0.03 97.48 108M 8.42 0.32 0.06 0.02 46.12 0.25 0.19 42.03. 0.05 0.09 0.00 97.54 108M 7.97 0.49 0.03 0.03 44.32 1.31 0.16 43.06 0.13 0.00 0.03 97.55 108M 8.38 0.41 0.08 0.03 46.26 0.53 0.15 41.61 0.10 0.00 0.00 97.56 108M 8.97 0.46 0.04 0.02 46.84 0.75 0.18 40.26 0.06 0.00 0.01 97.60 108M 10.54 0.59 0.06 0.05 48.60 0.54 0.41 36.67 0.18 0.00 0.00 97.63 108M 8.45 0.34 0.08 0.01 46.18 0.35 0.21 41.89 0.12 0.00 0.00 97.63 108M 9.50 0.57 0.03 0.03 47.12 0.68 0.25 39.25 0.10 0.13 0.00 97.66 108M 8.27 0.36 0.00 0.03 46.11 0.17 0.22 42.34 0.11 0.06 0.00 97.67 108M 8.45 0.43 0.07 0.04 46.02 0.37 0.19 41.89 0.09 0.16 0.00 97.72 108M 9.13 0.36 0.04 0.03 47.20 0.23 0.20 40.40 0.05 0.10 0.00 97.72 108M 6.96 0.34 0.05 0.03 43.54 0.06 0.22 46.40 0.06 0.07 0.01 97.75 108M 9.78 0.43 0.06 0.06 47.02 0.49 0.38 39.39 0.09 0.07 0.00 97.78 108M 8.35 0.34 0.06 0.01 46.24 0.18 0.25 42.15 0.12 0.12 0.00 97.82 108M 8.36 0.40 0.08 0.02 46.00 0.46 0.22 42.13 0.13 0.03 0.00 97.84 108M 8.09 0.36 0.02 0.04 45.10 0.33 0.15 43.59 0.10 0.08 0.00 97.86 108M 8.48 0.43 0.03 0.00 46.08 0.56 0.17 41.92 0.08 0.13 0.00 97.89 108M 7.93 0.51 0.05 0.05 44.35 1.33 0.17 43.53 0.05 0.01 0.00 97.97 108M 9.05 0.36 0.04 0.01 45.94 0.38 0.29 41.84 0.06 0.00 • 0.03 98.00 108M 8.08 0.39 0.09 0.03 45.86 0.32 0.11 43.03 0.07 0.03 0.00 98.01 108M 10.49 0.60 0.06 0.00 48.61 0.54 0.35 37.24 0.16 0.13 0.01 98.18 108M 8.96 0.47 0.06 0.03 46.76 0.52 0.16 41.09 0.06 0.09 0.00 98.20 108M 9.74 0.61 0.03 0.02 46.87 1.89 0.38 38.39 0.21 0.09 0.00 98.23 108M 9.86 0.48 0.07 0.06 47.51 1.12 0.32 38.69 0.10 0.04 0.00 98.25 108M 9.76 0.52 0.02 0.01 47.52 0.44 0.22 39.67 0.06 0.03 0.00 98.25 108M 10.51 0.06 0.02 0.07 50.78 0.62 0.45 35.42 0.18 0.23 0.00 98.34 108M 9.39 0.42 0.04 0.03 46.60 0.28 0.28 41.11 0.13 0.06 0.00 98.35 108M 0.06 0.00 0.03 0.05 49.04 0.04 1.86 47.25 0.00 0.02 0.05 98.41 108M 10.14 0.04 0.02 0.06 50.47 0.16 0.41 37.09 0.04 0.03 0.01 98.47 108M 10.82 0.25 0.04 0.02 49.43 2.84 0.44 34.63 0.11 0.00 0.00 98.58 108M 0.16 0.00 0.03 0.02 49.04 0.01 1.40 48.30 0.09 0.00 0.00 99.06 130F 8.35 0.36 0.06 0.02 46.28 0.30 0.24 41.85 0.10 0.06 0.00 97.63 130F 8.37 0.32 0.01 0.00 46.53 0.27 0.11 41.99 0.11 0.00 0.00 97.69 120 Sample MgO A1 2Q 3 SiQ 2 CaO TiQ 2 C r 2 Q 3 MnO Fe 2Q 3 NiO Nb 2 O s Ta 2Q ; Totals 130F 9.00 0.51 0.05 0.00 46.32 1.35 0.18 40.24 0.07 0.00 0.00 97.73 130F 8.12 0.33 0.04 0.01 46.06 0.36 0.21 42.61 0.06 0.01 0.00 97.81 130F 8.11 0.44 0.04 0.01 45.94 0.54 0.20 42.45 0.10 0.00 0.00 97.83 130F 8.72 0.33 0.02 0.04 47.40 0.28 0.26 40.70 0.07 0.03 0.00 97.87 130F 8.77 0.41 0.03 0.01 47.09 0.50 0.17 40.82 0.11 0.02 0.00 97.93 130F 8.74 0.41 0.03 0.03 47.08 0.79 0.17 40.74 0.01 0.00 0.02 98.02 OOF 8.85 0.40 0.04 0.01 47.47 0.30 0.25 40.71 0.00 0.00 0.00 98.03 130F 8.39 0.37 0.02 0.00 46.32 0.19 0.22 42.54 0.08 0.00 0.00 98.13 130F 8.64 0.48 0.07 0.01 46.72 1.18 0.20 40.76 0.10 0.10 0.00 98.27 130F 8.35 0.33 0.03 0.02 46.75 0.18 0.21 42.39 0.06 0.00 0.00 98.33 130F 9.61 0.36 0.05 0.00 47.98 1.10 0.17 38.88 0.13 0.05 0.01 98.36 130F 8.74 0.37 0.07 0.03 46.90 0.21 0.26 41.67 0.06 0.06 0.00 98.36 130F 10.00 0.36 0.03 0.03 47.97 0.27 0.27 39.23 0.13 0.09 0.00 98.38 130F 8.98 0.38 0.06 0.04 47.15 0.44 0.22 41.00 0.12 0.00 0.00 98.38 130F 8.65 0.34 0.04 0.01 46.86 0.40 0.20 41.61 0.12 0.12 0.02 98.38 130F 8.63 0.29 0.03 0.01 46.65 0.29 0.19 42.17 0.04 0.19 0.00 98.48 130F 8.80 0.37 0.07 0.01 47.25 0.73 0.29 40.84 0.10 0.06 0.00 98.51 130F 8.49 0.43 0.05. 0.00 46.53 0.48 0.23 42.32 0.01 0.00 0.00 98.54 130F 8.98 0.40 0.06 0.02 47.31 1.19 0.21 40.20 0.15 0.03 0.00 98.55 130F 9.35 0.48 0.03 0.01 47.21 1.11 0.24 39.96 0.18 0.00 0.00 98.57 130F 8.96 0.42 0.05 0.00 47.10 0.40 0.17 41.52 0.02 0.00 0.00 98.65 130F 9.50 0.43 0.06 0.02 48.10 0.26 0.31 39.93 0.07 0.00 0.00 98.68 130F 8.56 0.36 0.02 0.01 46.27 0.30 0.26 42.66 0.05 0.20 0.00 98.68 130F 8.52 0.36 0.04 0.04 46.53 0.22 0.20 42.70 0.11 0.00 0.00 98.72 130F 8.88 0.40 0.04 0.00 47.57 0.64 0.22 40.72 0.10 0.15 0.00 98.72 130F 9.22 0.32 0.08 0.01 47.39 0.67 0.24 40.57 0.15 0.08 0.00 98.73 130F 8.55 0.46 0.02 0.04 46.62 0.42 0.11 42.52 0.02 0.00 0.00 98.75 130F 8.44 0.43 0.09 0.01 46.40 0.64 0.18 42.38 0.08 0.11 0.00 98.77 130F 8.48 0.38 0.03 0.00 47.11 0.22 0.26 42.08 0.08 0.10 0.06 98.80 130F 9.12 0.35 0.05 0.02 47.21 0.31 0.16 41.41 0.07 0.08 0.02 98.80 130F 9.18 0.36 0.04 0.02 47.15 0.48 0.19 41.12 0.12 0.18 0.04 98.87 130F 8.93 0.38 0.02 0.02 46.80 0.48 0.25 41.72 0.08 0.22 0.01 98.92 130F 8.38 0.39 0.03 0.04 46.94 0.36 0.19 42.51 0.06 0.06 0.00 98.96 130F 8.37 0.42 0.06 0.00 46.49 0.69 0.21 42.55 0.19 0.00 0.00 98.98 130F 8.70 0.40 0.01 0.00 46.08 0.38 0.28 43.09 0.04 0.00 0.00 98.99 130F 9.21 0.41 0.06 0.00 47.69 0.29 0.21 41.05 0.07 0.03 0.00 99.02 130F 9.03 0.37 0.06 0.02 47.37 1.34 0.21 40.50 0.10 0.06 0.00 99.05 130F 9.07 0.47 0.04 0.00 47.25 0.44 0.13 41.60 0.16 0.00 0.00 99.17 130F 11.00 0.50 0.06 0.03 50.41 2.05 0.22 34.70 0.18 0.00 0.02 99.17 130F 10.18 0.21 0.03 0.03 51.09 0.24 0.32 36.96 0.12 0.00 0.01 99.18 130F 8.79 0.37 • 0.09 0.03 47.25 0.51 0.20 41.74 0.12 0.10 0.01 99.20 130F 9.45 0.47 0.07 0.02 48.11 0.35 0.17 40.58 0.03 0.00 0.00 99.24 130F 9.27 0.40 0.04 0.00 48.66 0.29 0.20 40.37 0.07 0.00 0.00 99.31 130F 9.68 0.46 0.06 0.03 49.08 0.34 0.20 39.52 0.11 0.04 0.00 99.53 130F 0.12 0.00 0.01 0.02 49.93 0.00 1.73 48.17 0.03 0.00 0.00 100.00 B O M 8.43 0.36 0.06 0.00 46.32 0.41 0.20 40.92 0.14 0.09 0.00 96.93 130M 8.02 0.35 0.07 0.02 45.53 0.38 0.17 42.53 0.08 0.00 0.00 97.15 130M 6.81 0.27 0.03 0.01 43.83 0.18 0.21 45.82 0.00 0.00 0.03 97.19 130M 8.70 0.33 0.06 0.04 46.70 0.40 0.27 40.62 0.06 0.03 0.00 97.20 130M 6.79 0.31 0.03 0.00 43.31 0.08 0.22 46.69 0.07 0.07 0.02 97.60 130M 9.07 0.36 0.06 0.02 46.18 0.34 0.21 41.06 0.07 0.23 0.01 97.60 130M 6.69 0.37 0.02 0.01 43.20 0.06 0.18 46.83 0.06 0.22 0.00 97.63 130M 9.04 0.51 0.06 0.00 45.97 0.85 0.16 41.04 0.04 0.00 0.00 97.67 130M 9.73 0.38 0.08 0.01 48.35 1.04 0.30 37.83 0.11 0.02 0.00 97.85 130M 8.69 0.41 0.04 0.03 46.73 0.68 0.25 40.88 0.07 0.14 0.00 97.92 130M 8.21 0.34 0.06 0.00 45.56 0.22 0.19 43.30 0.10 0.03 0.00 98.01 130M 8.74 0.30 0.02 0.02 47.69 0.28 0.22 40.57 0.09 0.11 0.00 98.04 130M 7.87 0.28 0.03 0.02 46.34 0.24 0.16 43.11 0.03 0.00 0.00 98.08 121 Sample MgO AI 2 Q 3 SiQ2 CaO TiQ 2 C r 2 Q 3 MnO Fe 2Q 3 NiO Nb 2 Q 5 Ta 2 Q 5 Totals 130M 9.53 0.36 0.08 0.02 47.94 0.32 0.24 39.51 0.09 0.01 0.00 98.09 130M 9.80 0.31 0.05 0.03 49.50 0.38 0.25 37.64 0.10 0.00 0.04 98.10 130M 0.70 0.00 0.00 0.00 48.85 0.03 1.28 47.29 0.00 0.00 0.00 98.14 130M 9.53 0.32 0.03 0.02 47.69 0.41 0.26 39.69 0.14 0.11 0.00 98.19 130M 8.83 0.49 0.01 0.01 46.66 0.99 0.23 40.80 0.19 0.05 0.00 98.25 130M 8.76 0.40 0.05 0.03 46.30 0.85 0.24 41.45 0.10 0.00 0.07 98.25 B O M 0.76 0.00 0.01 0.07 49.13 0.00 0.64 47.62 0.00 0.03 0.06 98.33 B O M 8.64 0.35 0.03 0.03 47.19 0.33 0.23 41.47 0.07 0.00 0.00 98.35 B O M 0.76 0.00 0.02 0.00 48.48 0.01 0.54 48.53 0.01 0.00 0.00 98.35 B O M 8.45 0.41 0.08 0.00 46.23 0.59 0.17 42.35 0.10 0.00 0.00 98.39 B O M 9.11 0.42 0.07 0.01 47.02 0.96 0.19 40.51 0.13 0.05 0.00 98.47 B O M 0.77 0.00 0.02 0.00 48.05 0.02 0.51 49.17 0.00 0.00 0.00 98.56 B O M 9.32 0.48 0.07 0.01 46.76 1.37 0.19 40.14 0.08 0.14 0.00 98.56 B O M 8.15 0.48 0.10 0.00 45.19 1.32 0.18 43.03 0.12 0.00 0.00 98.56 B O M 0.76 0.00 0.00 0.01 48.84 0.03 0.53 48.67 0.00 0.00 0.00 98.84 B O M 0.74 0.00 0.00 0.01 49.67 0.03 0.51 48.33 0.03 0.00 0.00 99.32 B O M 0.75 0.00 0.02 0.01 49.81 0.01 0.56 48.15 0.06 0.00 0.00 99.38 B O M 0.76 0.00 0.04 0.04 50.21 0.00 0.65 47.81 0.02 0.00 0.00 99.52 B O M 0.71 0.00 0.01 0.03 48.88 0.07 0.60 49.18 0.00 0.04 0.00 99.53 B O M 0.75 0.00 0.00 0.01 48.84 0.01 0.53 49.35 0.07 0.00 0.00 99.55 B O M 0.82 0.00 0.03 0.01 49.26 0.02 0.59 48.79 0.00 0.03 0.00 99.56 B O M 0.76 0.00 0.00 0.04 48.84 0.01 0.56 49.32 0.08 0.00 0.00 99.62 B O M 0.72 0.00 0.00 0.02 49.39 0.01 0.55 49.01 0.00 0.00 0.00 99.69 B O M 0.78 0.00 0.03 0.01 49.18 0.01 0.52 49.10 0.07 0.00 0.01 99.72 B O M 0.73 0.00 0.02 0.02 49.89 0.00 0.56 48.62 0.00 0.06 0.00 99.90 203F-1 9.11 0.40 0.11 0.01 47.27 0.46 0.22 40.68 0.11 0.01 0.00 98.38 203F-10 8.69 0.42 0.02 0.01 47.18 0.89 0.21 41.02 0.12 0.02 0.00 98.60 203F-12 8.84 0.35 0.07 0.02 47.02 0.54 0.16 40.78 0.10 0.17 0.00 98.05 203F-B 9.45 0.44 0.07 0.00 47.37 1.95 0.21 38.48 0.17 0.06 0.00 98.19 203F-14 8.74 0.36 0.03 0.04 47.13 0.43 0.19 41.55 0.11 0.12 0.01 98.71 203F-15 8.79 0.34 0.05 0.05 45.99 0.49 0.20 41.96 0.07 0.03 0.00 97.97 203F-16 8.08 0.29 0.02 0.03 46.34 0.18 0.21 42.78 0.05 0.00 0.02 98.01 203F-17 8.97 0.28 0.05 0.00 47.66 0.19 0.19 41.24 0.02 0.18 0.00 98.77 203F-19 8.83 0.30 0.13 0.02 47.02 0.27 0.28 41.71 0.15 0.00 0.00 98.71 203F-2 7.75 0.23 0.03 0.01 45.33 0.18 0.24 43.98 0.06 0.25 0.02 98.08 203F-20 8.90 0.39 0.03 0.00 46.72 1.19 0.21 40.99 0.14 0.00 0.00 98.57 203F-22 7.02 0.42 0.10 0.16 46.46 0.33 0.46 42.84 0.10 0.00 0.00 97.87 203F-23 8.90 0.42 0.08 0.00 47.21 0.40 0.19 41.44 0.08 0.14 0.00 98.88 203F-24 8.80 0.42 0.06 0.01 46.43 1.25 0.19 40.84 0.13 0.05 0.00 98.18 203F-26 9.51 0.34 0.04 0.02 48.19 0.96 0.19 39.28 0.15 0.05 0.00 98.73 203F-28 8.84 0.44 0.20 0.03 47.26 0.35 0.20 40.95 0.05 0.00 0.00 98.30 203F-29 8.77 0.31 0.02 0.02 47.50 0.68 0.26 40.94 0.10 0.01 0.01 98.63 203F-30 8.88 0.33 0.04 0.00 46.71 1.24 0.21 41.16 0.15 0.21 0.04 98.97 203F-31 8.78 0.34 0.03 0.04 47.56 0.39 0.25 40.68 0.02 0.09 0.00 98.18 203F-32 8.79 0.36 0.05 0.03 47.00 0.38 0.28 41.62 0.12 0.07 0.00 98.69 203F-33 8.23 0.32 0.05 0.02 46.22 0.49 0.17 42.51 0.10 0.00 0.00 98.12 203F-35 8.67 0.29 0.03 0.00 46.71 0.36 0.20 41.07 0.08 0.00 0.03 97.44 203F-36 9.02 0.38 0.04 0.03 47.46 0.56 0.28 40.84 0.00 0.02 0.00 98.63 203F-37 8.73 0.28 0.02 0.02 47.33 0.30 0.17 40.42 0.10 0.02 0.04 97.44 203F-38 8.96 0.29 0.04 0.01 47.03 0.63 0.22 40.66 0.04 0.01 0.00 97.89 203F-39 8.32 0.39 0.02 0.01 46.97 0.54 0.21 42.63 0.13 0.00 0.00 99.23 203F-4 8.67 0.30 0.01 0.01 46.61 0.28 0.22 41.84 0.08 0.00 0.07 98.10 203F-40 8.21 0.33 0.04 0.00 46.36 0.19 0.24 42.45 0.03 0.08 0.00 97.94 203F-41 8.85 0.37 0.12 0.01 47.33 0.47 0.29 41.08 0.07 0.00 0.00 98.58 203F-42 8.88 0.34 0.03 0.03 47.43 0.66 0.17 40.82 0.11 0.00 0.00 98.47 203F-43 9.41 0.24 0.03 0.01 49.09 0.60 0.22 38.67 0.09 0.11 0.00 98.48 203F-44 8.32 0.37 0.07 0.01 46.59 0.60 0.20 41.75 0.06 0.14 0.00 98.11 203F-45 8.87 0.38 • 0.05 0.00 46.13 1.15 0.19 40.79 0.12 0.12 0.00 97.80 122 Sample MgO A1 20, Si0 2 CaO T i 0 2 MnO Fe 2 0, NiO Nb 2 O s T a 2 O s Totals 203F-46 8.90 0.26 0.04 0.02 47.81 0.71 0.21 40.45 0.12 0.00 0.00 98.53 203F-47 9.02 0.36 0.14 0.00 47.41 0.64 0.17 41.27 0.11 0.07 0.00 99.18 203F-48 9.99 0.29 0.01 0.00 48.57 4.23 0.24 35.70 0.11 0.01 0.00 99.15 203F-49 8.81 0.38 0.06 0:02 46.09 1.26 0.20 41.12 0.12 0.03 0.00 98.10 203F-5 9.53 0.39 0.14 0.05 48.05 0.96 0.21 38.94 0.11 0.06 0.00 98.44 203F-50 8.63 0.34 0.01 0.00 46.83 0.39 0.19 41.74 0.09 0.16 0.00 98.39 203F-6 9.03 0.43 0.01 0.00 " 47.53 0.38 0.24 40.99 0.14 0.06 0.00 98.82 203F-7 8.71 0.32 0.06 0.02 46.62 0.32 0.22 41.89 . 0.15 0.01 0.00 98.32 203F-8 9.62 0.30 0.19 0.02 47.07 0.93 0:22 38.79 0.12 0.01 0.00 97.28 203F-9 9.46 0.34 0.03 0.00 47.45 1.05 0.17 39.42 0.14 0.15 0.00 98.22 203M-13 9.13 0.33 0.05 0.00 46.95 0.33 0.24 40.35 0.04 0.06 0.00 97.48 203M-14 8.92 0.40 0.03 0.00 46.25 1.25 0.16 40.29 0.10 0.10 0.02 97.53 203M-17 8.42 0.24 0.05 0.00 46.36 0.22 0.18 42.05 0.12 0.00 0.00 97.65 203M-2 8.58 0.47 0.09 0.02 45.44 1.22 0.17 41.59 0.09 0.04 0.00 97.70 203M-23 8.29 0.37 0.07 0.00 46.14 0.85 0.14 41.26 0.07 0.16 0.00 97.35 203M-27 8.23 0.26 0.05 0.01 45.96 0.29 0.23 42.45 0.04 0.00 0.01 97.54 203M-29 9.85 0.27 0.02 0.02 48.03 4.59 0.21 35.52 0.12 0.00 0.00 98.62 203M-30 9.06 0.22 0.05 0.11 48.44 4.05 0.43 36.44 0.16 0.05 0.00 99.00 203M-33 8.71 0.42 0.05 0.02 47.21 0.35 0.20 40.93 0.10 0.04 0.00 98.02 203M-36 9.10 0.45 0.04 0.02 46.71 0.88 0.19 40.95 0.11 0.10 0.00 98.55 203M-38 10.12 0.36 0.00 0.00 48.01 4.14 0.22 35.26 0.14 0.00 0.00 98.26 203M-4 8.61 0.41 0.06 0.02 46.99 0.37 0.22 41.37 0.04 0.10 0.00 98.20 203M-40 9.74 0.35 0.06 0.02 47.83 0.29 0.21 39.85 0.15 0.00 0.00 98.51 203M-44 9.93 0.33 0.08 0.10 47.14 0.36 0.48 38.51 0.17 0.11 0.00 97.21 203M-45 9.96 0.32 0.03 0.01 48.05 4.17 0.23 35.48 0.13 0.14 0.03 98.54 203M-46 9.04 0.45 0.12 0.03 46.21 1.16 0.17 40.61 0.18 0.13 0.00 98.11 203M-48 8.19 0.47 0.04 0.01. 44.88 1.54 0.25 42.45 0.15 0.15 0.02 98.15 203M-49 10.06 0.29 0.02 0.03 47.80 4.10 0.22 35.45 0.15 0.06 0.00 98.16 203M-6 8.85 0.28 0.03 0.02 47.01 0.49 0.25 40.95 0.11 0.00 0.00 97.99 203M-7 8.83 0.41 0.03 0.05 45.85 0.69 0.15 41.06 0.09 0.06 0.00 97.22 248F-1 8.60 0.43 0.07 0.01 46.37 1.00 0.19 41.12 0.15 0.03 0.00 97.97 248F-10 8.40 0.45 0.13 0.04 46.22 0.80 0.17 41.31 0.14 0.14 0.01 97.81 248F-11 9.42 0.48 0.06 0.01 48.40 0.54 0.20 39.10 0.13 0.02 0.00 98.37 248F-12 8.81 0.49 0.12 0.01 46.40 1.33 0.18 40.29 0.12 0.00 0.05 97.81 248F-13 9.14 0.35 0.04 0.04 47.23 0.48 0.23 39.58 0.09 0.00 0.00 97.20 248F-14 8.11 0.32 0.03 0.02 45.43 0.23 0.17 42.92 0.09 0.07 0.00 97.40 248F-15 8.41 0.31 0.05 0.04 46.90 0.40 0.21 41.11 0.05 0.06 0.00 97.54 248F-16 8.13 0.31 0.03 0.02 46.12 0.53 0.19 42.26 0.09 0.13 0.00 97.80 248F-17 9.75 0.24 0.02 0.10 49.14 0.78 0.25 37.92 0.14 0.14 0.00 98.48 248F-18 8.50 0.41 0.04 0.08 45.74 1.29 0.17 41.35 0.13 0.15 0.00 97.86 248F-19 8.03 0.31 0.04 0.02 46.34 0.58 0.19 42.36 0.08 0.00 0.00 97.94 248F-2 8.38 0.49 0.20 0.02 45.86 0.92 0.20 41.08 0.03 0.00 . 0.00 97.18 248F-20 8.40 0.40 0.04 0.00 46.00 1.22 ' 0.21 41.74 0.09 0.11 0.00 98.22 248F-21 7.95 0.27 0.05 0.01 46.47 0.35 0.23 42.46 0.04 0.00 0.00 97.82 248F-22 7.12 0.30 0.05 0.08 44.71 0.22 0.22 44.10 0.03 0.11 0.00 96.95 248F-23 8.69 0.26 0.02 0.02 46.79 0.35 0.24 40.77 0.09 0.00 0.00 97.24 248F-24 8.73 0.42 0.05 0.03 46.15 1.01 0.22 41.09 0.08 0.00 0.00 97.78 248F-25 8.78 0.44 0.06 0.02 46.19 1.31 0.17 40.41 0.17 0.05 0.00 97.58 248F-26 8.08 0.37 0.04 0.09 46.02 0.54 0.20 41.79 0.07 0.01 0.00 97.21 248F-27 8.80 0.43 0.03 0.01 46.79 0.72 0.20 40.78 0.06 0.00 0.00 97.84 248F-28 8.36 0.30 0.05 0.01 46.74 0.47 0.25 41.31 0.12 0.17 0.01 97.79 248F-29 8.10 0.44 0.03 0.03 44.80 1.69 0.17 42.14 0.07 0.09 0.00 97.56 248F-30 8.87 0.45 0.02 0.00 46.34 1.35 0.22 40.80 0.13 0.01 0.03 98.21 248F-31 8.15 0.35 0.04 0.02 46.24 0.21 0.28 42.14 0.02 0.00 0.00 97.47 248F-32 8.40 0.45 0.06 0.02 46.43 1.03 0.17 41.26 0.12 0.11 0.00 98.06 248F-33 9.15 0.39 0.09 0.02 47.26 1.17 0.19 39.50 0.05 0.10 0.00 97.92 248F-34 8.54 0.36 0.04 0.00 46.50 0.92 0.22 40.44 0.19 0.02 0.00 97.24 248F-35 8.99 0.55 0.14 0.04 46.28 1.31 0.17 40.09 0.16 0.09 0.00 97.81 123 Sample MgO A1 20, SiOj CaO T i 0 2 Cr203 MnO Fe 2 0 3 NiO Nb 2 O s T a 2 O s Totals 248F-36 8.51 0.40 0.04 0.00 46.44 1.01 0.18 41.31 0.12 0.19 0.00 98.20 248F-37 8.22 0.48 0.02 0.03 46.17 1.12 0.13 42.16 0.10 0.08 0.00 98.50 248F-38 9.43 0.38 0.06 0.00 47.41 1.37 0.18 38.72 0.14 0.00 0.00 97.69 248F-39 9.56 0.23 0.03 0.02 49.23 1.13 0.35 37.45 0.15 0.09 0.00 98.24 248F-4 8.45 0.37 0.00 0.00 46.11 0.96 0.18 41.19 0.11 .0.00 0.00 97.40 248F-40 8.33 0.42 0.02 0.02 45.45 1.15 0.18 41.69 0.09 0.15 0.00 97.51 248F-41 8.81 0.31 0.05 0.01 47.34 0.29 0.26 41.04 0.08 0.10 0.00 98.30 248F-42 8.16 0.28 0.03 0.04 46.84 0.23 0.23 41.61 0.04 0.00 0.00 97.46 248F-43 8.50 0.43 0.06 0.01 45.79 , 1.22 0.16 41.10 0.12 0.14 0.00 97.53 248F-45 8.78 0.48 0.04 0.01 46.33 1.33 0.20 40.77 0.15 0.00 0.03 98.12 248F-46 9.60 0.48 0.06 0.00 47.78 2.00 0.23 38.12 0.14 0.09 0.00 98.48 248F-47 8.39 0.50 0.16 0.09 46.15 0.89 0.15 40.78 0.09 0.04 0.00 97.23 248F-48 8.44 0.46 0.11 0.03 45.19 1.18 0.13 41.93 0.15 0.11 0.00 97.74 248F-49 8.24 0.34 0.06 0.00 46.24 0.52 0.19 41.90 0.10 0.06 0.00 97.67 248F-5 8.16 0.43 0.06 0.03 45.58 0.85 0.21 42.03 0.08 0.13 0.00 97.56 248F-50 9.13 0.46 0.05 0.08 48.18 0.30 0.22 39.41 0.12 0.05 0.01 98.01 248F-6 8.12 0.31 0.06 0.03 46.14 0.23 0.20 42.45 0.10 0.11 0.00 97.75 248F-7 8.54 0.45 0.05 0.01 46.32 0.99 0.10 41.13 0.08 0.15 0.00 97.82 248F-8 8.18 0.38 0.06 0.01 45.81 0.61 0.23 41.89 0.11 0.09 0.00 97.37 248F-9 8.04 0.39 0.04 0.03 46.27 0.36 0.26 41.53 0.09 0.05 0.00 97.05 248M-1 7.98 0.54 0.04 0.06 44.02 1.43 0.17 42.91 0.05 0.00 0.02 97.22 248M-10 9.03 0.46 0.04 0.02 46.30 1.03 0.25 40.44 0.08 0.13 0.00 97.77 248M-12 9.67 0.31 0.02 0.07 47.84 0.35 0.32 38.69 0.10 0.06 0.00 97.43 248M-13 9.75 0.47 0.06 0.00 48.11 1.85 0.16 37.13 0.18 0.07 0.00 97.79 248M-16 6.64 0.36 0.02 0.01 43.26 0.08 0.17 45.91 0.07 0.09 0.00 96.61 248M-18 9.65 0.38 0.03 0.10 47.74 1.24 0.29 38.03 0.07 0.12 0.02 97.67 248M-19 8.85 0.43 0.05 0.01 46.64 0.84 0.16 40.28 0.10 0.00 0.00 97.36 248M-20 8.27 0.45 0.08 0.00 45.00 1.17 0.18 41.46 0.05 0.00 0.00 96.66 248M-21 8.26 0.41 0.03 0.02 46.02 0.49 0.15 41.34 0.11 0.21 0.00 97.03 248M-22 8.90 0.45 0.07 0.02 46.61 0.76 0.19 40.59 0.11 0.06 0.00 97.76 248M-28 8.65 0.33 0.05 0.00 46.86 0.37 0.23 40.61 0.08 0.00 0.06 97.25 248M-31 8.76 0.45 0.09 0.02 46.36 0.99 0.17 40.23 0.14 0.02 0.00 97.23 248M-32 9.55 0.34 0.03 0.04 48.58 1.02 0.25 37.70 0.20 0.08 0.00 97.80 248M-33 8.75 0.43 0.01 0.01 46.46 0.94 0.22 40.30 0.14 0.06 0.03 97.34 248M-36 8.59 0.42 0.04 0.02 46.13 1.00 0.17 41.18 0.08 0.05 0.00 97.68 248M-37 8.94 0.40 0.07 0.04 46.74 1.30 0.22 39.51 0.11 0.00 0.00 97.33 248M-38 9.16 0.33 0.05 0.21 47.62 0.33 0.20 39.69 0.13 0.18 0.00 97.89 248M-40 9.18 0.30 0.03 0.03 47.38 0.31 0.19 40.13 0.06 0.20 0.00 97.82 248M-43 10.05 0.13 0.04 0.03 50.69 1.03 0.29 35.72 0.18 0.06 0.03 98.26 248M-44 8.51 0.42 0.06 0.02 45.46 1.22 0.18 41.16 0.10 0.03 0.00 97.15 248M-45 8.38 0.44 0.06 0.03 45.79 1.19 0.19 41.30 0.10 0.00 0.07 97.54 248M-47 8.80 0.48 0.04 0.03 46.36 0.99 0.23 40.80 0.12 0.17 0.00 98.02 248M-48 8.96 0.47 0.04 0.02 46.43 0.96 0.17 40.59 0.09 0.00 0.00 97.74 248M-49 8.51 0.43 0.02 0.01 46.27 0.99 0.18 41.26 0.12 0.00 0.00 97.79 248M-50 8.64 0.56 0.05 0.02 45.11 1.43 0.18 41.05 0.14 0.06 0.00 97.25 248M-8 9.08 0.32 0.06 0.07 48.43 0.42 0.19 39.38 0.12 0.01 0.00 98.09 251F-10 9.93 0.43 0.02 0.03 48.67 0.41 0.19 39.21 0.06 0.00 0.00 98.94 251F-2 9.17 0.41 0.00 0.02 47.81 0.36 0.25 40.45 0.11 0.19 0.00 98.77 251F-20 9.30 0.43 0.02 0.00 47.60 0.41 0.27 40.41 0.09 0.00 0.00 98.54 251F-23 9.36 0.46 0.01 6.03 48.00 0.43 0.21 40.66 0.08 0.03 0.05 99.32 251F-28 8.95 0.34 0.01 0.02 48.16 0.47 0.16 41.23 0.17 0.11 0.00 99.62 251F-33 8.75 0.53 0.24 0.06 47.06 0.42 0.25 41.63 0.13 0.00 0.00 99.07 251F-35 9.94 0.08 0.00 0.03 49.94 0.97 0.27 37.28 0.08 0.00 0.02 98.60 251F-37 9.57 0.46 0.06 0.03 48.10 0.41 0.24 39.48 0.12 0.09 0.00 98.56 251F-50 7.81 0.37 0.01 0.02 45.96 0.36 0.12 43.76 0.06 0.11 0.00 98.56 251M-2 8.34 0.46 0.04 0.01 46.54 0.62 0.20 42.01 0.16 0.15 0.00 98.53 251M-30 8.65 0.34 0.01 0.01 47.06 0.47 0.24 40.84 0.05 0.16 0.03 97.85 251M-34 8.40 0.35 0.00 0.03 46.52 0.19 0.19 42.62 0.00 0.00 0.00 98.31 124 Sample MgO A12Q3 SiQ 2 CaO TiQ 2 C r 2 Q 3 MnO Fe 2 Q 3 NiO Nb 2 Q 5 T a 2 0 5 Totals 251M-46 9.29 0.46 0.28 0.04 47.62 0.32 0.25 39.81 0.14 0.05 0.00 98.27 251M-48 8.11 0.38 0.03 0.03 45.98 0.47 0.19 42.53 0.12 0.12 0.00 97.94 251M-6 7.90 0.39 0.06 0.00 45.67 0.36 0.25 43.34 0.08 0.05 0.01 98.12 251M-9 8.87 0.43 0.02 0.05 45.81 0.43 0.24 42.50 0.07 0.05 0.02 98.47 259F-1 8.69 0.48 0.04 0.02 46.67 0.72 0.24 41.86 0.11 0.01 0.00 98.84 259F-12 8.69 0.44 0.05 0.04 46.63 0.72 0.18 41.04 0.16 0.00 0.00 97.94 259F-16 8.26 0.44 0.03 0.07 45.89 0.71 0.24 41.81 0.08 0.00 0.00 97.54 259F-17 8.28 0.37 0.05 0.02 46.85 0.23 0.18 41.85 0.03 0.00 0.00 97.85 259F-18 8.38 0.40 0.04 0.01 47.01 0.39 0.19 41.62 0.14 0.02 0.00 98.18 259F-19 8.84 0.53 0.05 0.04 46.58 0.90 0.21 41.14 0.05 0.07 0.00 98.41 259F-2 8.84 0.45 0.02 0.01 47.09 0.75 0.28 41.03 0.12 0.04 0.00 98.63 259F-26 8.89 0.46 0.04 0.05 46.14 1.33 0.24 40.15 0.09 0.00 0.00 97.40 259F-27 7.78 0.32 0.04 0.00 46.01 0.14 0.22 43.47 0.06 0.15 0.00 98.19 259F-29 8.76 0.44 0.03 0.01 46.65 0.63 0.19 41.18 0.08 0.10 0.00 98.08 259F-32 8.45 0.47 0.25 0.02 46.67 0.25 0.20 41.25 0.10 0.12 0.00 97.78 259F-35 8.77 0.41 0.03 0.01 46.81 0.79 0.20 41.36 0.08 0.05 0.00 98.51 259F-36 9.00 0.38 0.05 0.01 47.99 0.50 0.23 39.76 0.00 0.00 0.00 97.93 259F-38 7.76 0.30 0.05 0.14 45.80 0.14 0.25 42.64 0.00 0.08 0.00 97.17 259F-4 8.37 0.35 0.01 0.04 46.88 0.20 0.27 42.11 0.04 0.06 0.00 98.33 259F-42 9.23 0.43 0.07 0.06 48.51 0.49 0.20 39.47 0.05 0.00 0.00 98.50 259F-46 8.73 0.44 0.03 0.03 46.99 0.81 0.22 40.56 0.04 0.10 0.00 97.95 259F-47 8.52 0.34 0.05 0.01 47.05 0.40 0.24 41.56 0.09 0.16 0.00 98.42 259F-5 8.92 0.53 0.08 0.06 46.95 0.96 0.18 40.91 0.13 0.14 0.00 98.85 259F-50 8.88 0.58 0.36 0.05 46.80 0.46 0.24 40.60 0.07 0.00 0.00 98.04 259F-6 7.79 0.46 0.06 0.06 44.74 1.78 0.18 43.61 0.20 0.00 0.00 98.88 259F-7 8.32 0.40 0.04 0.02 47.20 0.32 0.20 42.16 0.00 0.00 0.00 98.64 259F-8 8.51 0.38 0.04 0.03 46.73 1.29 0.18 41.04 0.06 0.00 0.00 98.25 259F-9 9.89 0.65 0.03 0.49 47.45 1.84 0.28 37.97 0.12 0.06 0.01 98.78 259M-13 0.04 0.00 0.04 0.34 48.85 0.05 5.43 43.49 0.05 0.02 0.00 98.31 259M-38 8.93 0.36 0.03 0.03 47.90 0.33 0.17 40.16 0.06 0.00 0.00 97.98 259M-42 8.69 0.44 0.10 0.01 46.53 0.73 0.14 41.03 0.13 0.00 0.00 97.81 259M-43 8.69 0.43 0.04 0.01 46.49 0.78 0.23 41.21 0.06 0.11 0.06 98.11 Sample number indicates the depth of the sample. Samples at 108 and 130 m are autolithic volcaniclastic . kimberlite breccia. Samples at 203 and 248 m are heterolithic volcaniclastic kimberlite breccia. Samples at 251 and 259 m are lithic breccia. F means that the grains were from the Frantz separate, and M means the grain were separated using a magnet. 125 Appendix C: Compositional analysis of magnetite grains from the Anuri kimberlite Table C . l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for magnetite grains separated from the Anuri kimberlite Sample MgO A1 20, SiOj CaO C r 2 0 , MnO Fe 2 0, NiO Nb 2 O s T a 2 O s Totals 108M 0.11 0.96 6.81 6.18 18.97 0.28 0.40 58.88 0.06 0.00 0.00 92.66 130M 0.42 0.49 8.81 7.05 21.87 0.02 3.45 52.89 0.05 0.00 0.00 95.06 130M 0.24 0.66 10.51 9.42 18.36 0.14 1.64 53.61 0.00 0.02 0.00 94.61 130M 0.11 0.68 6.05 5.23 18.38 0.05 2.12 62.32 0.00 0.00 0.00 94.93 130M 0.12 0.31 0.00 0.02 0.05 1.49 0.03 90.77 0.08 0.00 0.00 92.87 130M 0.11 0.22 0.02 0.00 0.04 0.17 0.04 91.51 0.09 0.00 0.00 92.19 130M 0.10 0.26 0.03 0.01 0.04 0.47 0.00 92.01 0.07 0.00 0.00 92.99 130M 0.06 0.01 0.03 0.01 0.00 0.00 0.06 92.05 0.00 0.00 0.00 92.21 130M 0.16 0.46 0.01 0.01 0.08 0.30 0.00 92.13 0.03 0.00 0.01 93.17 130M 0.14 0.45 0.03 0.00 0.05 0.33 0.00 92.14 0.04 0.00 0.02 93.20 130M 0.14 0.47 0.09 0.02 0.11 0.21 0.04 92.73 0.01 0.00 0.00 93.81 203F-11 0.10 0.20 0.33 0.01 1.19 0.00 0.05 88.89 0.10 0.00 0.00 90.86 203F-18 0.21 0.19 0.48 0.03 1.04 0.00 0.01 88.97 0.00 0.00 0.00 90.93 203F-21 0.09 0.14 0.37 0.04 7.73 0.01 0.05 83.48 0.03 0.00 0.00 91.94 203F-27 21.84 5.52 34.24 0.68 0.34 0.04 0.09 31.16 0.08 0.00 0.00 93.99 203F-3 0.93 0.88 1.67 0.04 0.19 0.00 0.04 86.72 0.00 0.00 0.00 90.47 203F-34 0.49 0.12 0.75 0.08 2.56 0.03 0.02 85.20 0.00 0.06 0.00 89.32 248M-14 0.96 0.63 0.79 0.50 8.21 2.34 1.42 77.79 0.11 0.00 0.00 92.75 248M-17 1.57 0.96 0.21 0.16 9.47 17.29 2.03 61.30 0.15 0.00 0.00 93.14 248M-24 4.28 0.92 0.07 0.00 0.97 24.13 0.56 63.69 0.25 0.04 0.00 94.91 248M-25 4.67 1.41 0.95 0.10 8.08 26.17 1.85 50.30 0.18 0.06 0.00 93.77 248M-26 0.17 0.14 0.13 0.26 0.63 0.01 0.06 91.68 0.00 0.00 0.00 93.06 248M-3 2.65 1.10 0.44 0.10 9.29 20.04 2.04 58.22 0.15 0.00 0.00 94.02 248M-35 5.24 1.22 0.05 0.00 0.78 29.14 0.43 56.43 0.20 0.00 0.03 93.52 248M-39 0.13 0.01 0.06 0.04 0.00 0.00 0.06 92.69 0.02 0.00 0.00 93.01 248M-46 0.51 1.25 0.61 0.07 14.83 2.15 2.63 70.45 0.00 0.00 0.00 92.51 248M-7 0.45 0.69 0.48 0.08 9.54 5.16 1.72 75.23 0.10 0.00 0.00 93.45 251F-13 1.99 1.48 4.06 0.18 9.47 0.12 1.95 72.56 0.08 0.00 0.00 91.89 251F-14 0.12 0.00 0.25 0.00 0.04 0.00 0.03 90.10 0.05 0.00 0.00 90.59 251F-16 0.12 0.07 1.66 0.05 0.19 0.00 0.02 87.29 0.00 0.02 0.00 89.43 251F-18 1.42 0.79 2.32 0.02 0.22 0.01 0.02 86.45 0.01 0.00 0.00 91.25 251F-19 0.59 0.34 1.32 0.07 0.61 0.00 0.21 87.50 0.00 0.00 0.00 90.62 251F-22 0.09 1.79 0.06 0.00 14.60 5.99 3.03 68.78 0.06 0.00 0.00 94.40 251F-24 1.26 1.04 2.66 0.09 0.32 0.00 0.04 85.28 0.05 0.00 0.00 90.75 251F-25 0.08 0.02 0.06 0.00 0.04 0.40 0.00 92.45 0.04 0.00 0.00 93.09 251F-26 0.14 0.10 0.89 0.00 0.04 0.00 0.03 89.71 0.00 0.00 0.00 90.91 251F-27 0.16 0.15 1.01 0.03 0.10 0.02 0.02 89.23 0.09 0.00 0.00 90.81 251F-29 0.15 0.01 0.06 0.02 0.00 0.00 0.02 94.45 0.01 0.00 0.00 94.72 251F-3 1.35 0.31 1.67 0.03 . 0.30 0.04 0.16 89.67 0.01 0.00 0.00 93.53 251F-32 0.26 0.16 1.16 0.06 0.11 0.05 0.02 88.76 0.01 0.00 0.00 90.60 251F-36 0.36 0.35 1.13 0.03 0.12 0.00 0.00 88.92 0.05 0.00 0.00 90.96 251F-38 0.11 0.00 0.12 0.01 0.05 0.00 0.00 90.19 0.01 0.00 0.00 90.50 251F-39 0.34 0.22 0.72 0.01 0.06 0.03 0.01 88.02 0.06 0.00 0.00 89.47 251F-42 0.41 0.30 1.10 0.06 0.08 0.03 0.02 88.37 0.03 0.00 0.00 90.40 251F-43 11.41 12.83 31.38 0.08 2.28 0.02 0.27 31.63 0.01 0.00 0.00 89!92 251F-44 15.74 13.74 31.84 0.09 0.93 0.07 0.23 24.91 0.00 0.00 0.00 87.54 126 Sample MgO A12Q, SiQ2 CaO TiQ 2 Cr 2Q,, MnQ Fe 2 0 3 NiO Nb 2 Q 5 T a 2 O s Totals 251F-45 0.36 0.19 0.86 0.03 0.18 0.00 0.00 88.63 0.06 0.01 0.00 90.34 251F-48 0.19 0.24 1.56 0.09 0.12 0.00 0.00 88.29 0.00 0.00 0.00 90.47 251F-49 0.11 0.03 0.55 0.02 0.02 0 ;00 0.01 89.71 0.01 0.00 0.00 90.45 251F-7 0.41 0.22 2.52 0.51 5.46 0.43 0.74 80.61 0.05 0.00 0.00 90.96 251F-8 0.39 0.31 0.82 0.02 0.11 0.00 0.05 89.12 0.00 0.00 0.00 90.82 251F-9 0.59 0.46 1.67 0.05 0.14 0.00 0.04 88.01 0.00 0.00 0.00 90.96 251M-1 10.55 3.02 0.07 0.01 11.97 29.31 0.39 42.14 0.24 0.00 0.00 97.69 251M-10 0.14 0.07 0.34 0.28 0.55 0.00 0.00 92.25 0.03 0.00 0.00 . 93.66 251M-12 2.97 0.99 5.84 0.60 3.83 0.36 0.65 75:91 0.05 0.00 0.00 91.20 251M-14 0.33 0.87 8.55 7.26 14.01 0.00 0.69 62.26 0.06 0.00 0.00 94.03 251M-15 0.11 0.02 0.03 0.01 0.00 0.04 0.13 93.56 0.05 0.00 0.00 93.94 251M-16 0.22 0.12 0.76 0.02 0.06 0.01 0.04 89.44 0.00 0.00 0.00 90.67 251M-17 0.28 0.19 0.84 0.01 0.10 0.00 0.02 89.66 0.05 0.00 0.00 91.15 251M-18 0.30 0.68 .1.41 0.23 4.41 0.39 0.47 84.41 0.06 0.00 0.00 92.35 251M-20 0.19 0.09 0.35 0.01 0.03 0.05 0.00 89.34 0.00 0.00 0.00 90.06 251M-22 0.17 0.06 0.66 0.06 0.04 0.00 0.05 89.57 0.01 0.00 0.00 90.62 251M-23 0.38 0.16 1.20 0.01 3.04 0.05 0.02 86.45 0.04 0.03 0.00 91.38 251M-24 7.65 22.09 45.08 0.27 0.39 0.02 0.00 7.69 0.15 0.10 0.00 83.45 251M-25 0.09 0.02 0.04 0.05 0.10 0.08 0.08 93.50 0.00 0.00 0.00 93.96 251M-26 0.59 0.32 1.22 0.04 0.19 0.04 0.04 88.57 0.04 0.00 0.00 91.05 251M-29 0.69 0.56 5.03 3.00 9.27 0.09 0.48 75.54 0.00 0.00 0.00 94.65 251M-3 0.18 0.37 ' 2.70 2.25 13.58 0.03 0.29 74.50 0.07 0.03 0.00 94.00 251M-31 0.23 0.11 0.79 0.04 0.02 0.03 0.00 89.31 0.00 0.00 0.00 90.52 251M-32 0.08 0.04 0.01 0.00 0.01 0.05 0.14 94.42 0.00 0.00 0.04 94.80 251M-33 0.18 0.18 0.66 0.02 0.13 0.02 0.00 89.32 0.02 0.00 0.00 90.53 251M-35 11.66 3.91 0.08 0.03 12.33 27.03 0.32 42.09 0.21 0.00 0.00 97.67 251M-36 1.94 0.70 1.19 0.04 0.01 0.00 0.10 89.22 0.01 0.00 0.00 93.21 251M-37 0.67 0.71 1.48 0.05 0.30 0.00 0.02 83.50 0.01 0.00 0.00 86.74 251M-39 0.09 0.06 0.99 0.03 0.09 0.01 0.03 90.11 0.00 0.00 0.00 91.40 251M-40 0.35 0.24 1.06 0.06 0.09 0.00 0.04 88.85 0.00 0.00 0.00 90.69 251M-41 4.32 4.33 0.33 0.07 10.18 0.03 0.86 73.71 0.12 0.01 0.00 93.96 251M-42 0.13 0.01 0.04 0.04 0.03 0.01 0.05 92.90 0.03 0.00 0.00 93.24 251M-43 0.01 0.19 85.74 0.01 0.05 0.01 0.02 0.04 0.00 0.08 0.00 86.15 251M-45 0.06 1.80 0.05 0.05 14.24 5.42 2.57 70.26 0.10 0.00 0.00 94.54 251M-47 12.65 15.27 37.59 0.02 2.45 0.00 0.25 19.49 0.03 0.01 0.00 87.76 251M-49 0.55 0.41 0.99 0.04 0.07 0.03 0.01 88.52 0.03 0.01 0.00 90.67 251M-5 12.25 5.18 0.07 0.03 13.25 0.04 0.66 63.71 0.03 0.00 0.00 95.22 251M-50 0.07 0.30 0.38 0.16 11.81 0.02 1.20 79.06 0.00 0.00 0.00 93.02 251M-7 0.21 0.19 1.35 0.04 0.37 0.00 0.02 87.77 0.00 0.00 0.00 89.94 251M-8 0.22 0.35 1.75 0.35 7.69 0.47 0.56 80.32 0.04 0.00 0.00 91.75 259F-10 0.12 0.11 0.22 0.03 1.88 0.03 0.00 88.10 0.00 0.00 0.00 90.48 259F-11 0.18 1.01 0.08 0.10 10.40 16.52 2.41 63.14 0.14 0.03 0.00 94.01 259F-14 0.07 0.65 0.04 0.13 12.83 8.16 2.27 68.63 0.14 0.00 0.00 92.91 259F-22 0.06 0.05 0.38 , 0.02 10.87 0.05 0.07 79.36 0.00 0.00 0.00 90.87 259F-24 0.15 0.57 0.19 0.17 10.55 1.63 1.60 79.09 0.16 0.00 0.00 94.12 259F-25 0.09 0.07 0.03 0.03 3.36 0.00 0.00 85.43 0.00 0.00 0.00 89.02 259F-28 0.14 0.14 1.19 0.07 0.21 0.00 0.02 86.89 0.04 0.00 0.00 88.70 259F-3 0.06 0.12 0.19 0.10 1.35 0.09 0.00 87.67 0.01 0.00 0.00 89.59 259F-30 0.56 0.62 3.42 2.26 15.06 0.02 1.01 71.10 0.00 0.00 0.00 94.05 259F-33 0.06 0.03 0.07 0.21 0.04 0.42 0.02 91.38 0.06 0.08 0.00 92.36 259F-37 0.45 0.04 0.10 0.03 0.03 0.02 0.15 92.05 0.03 0.00 0.00 92.91 259F-40 0.14 1.17 0.04 0.16 11.74 16.29 2.68 62.10 0.26 0.09 0.00 94.67 259F-41 0.29 0.23 0.35 0.03 0.07 0.02 0.04 91.25 0.00 0.01 0.00 92.28 259F-44 4.65 2.38 8.10 0.18 8.84 0.10 1.09 64.73 0.00 0.00 0.00 90.07 127 Sample MgO A12Q3 SiQ 2 CaO TiQ 2 C r 2 Q 3 MnO Fe 2 Q 3 NiO Nb 2 Q 5 T a 2 O s Totals 259F-48 0.05 0.52 0.09 0.08 13.33 3.70 2.02 71.63 0.20 0.00 0.00 91.63 259M-10 ,0.09 0.55 0.06 0.10 13.26 3.54 1.71 73.05 0.09 0.00 0.00 92.45 259M-11 0.08 0.01 0.03 0.01 0.00 0.00 0.04 92.74 0.03 0.00 0.01 92.95 259M-12 1.23 0.77 1.43 0.11 11.39 4.13 1.76 72.38 0.04 0.00 0.00 93.24 259M-15 0.21 1.93 0.25 0.05 12.70 8.58 2.41 68.37 0.15 0.00 0.00 94.65 259M-16 0.06 0.69 1.54 1.45 19.95 0.05 1.30 68.62 0.03 0.00 0.00 93.70 259M-17 3.33 1.05 0.06 0.07 8.75 25.18 2.00 54.06 0.15 0.02 0.00 94.66 259M-18 3.07 1.02 0.27 0.05 7.23 26.55 1.62 54.15 0.17 0.00 0.00 94.13 259M-2 0.09 0.86 0.09 0.07 12.12 12.15 2.07 65.36 0.19 0.00 0.00 92.99 259M-20 0.01 1.40 12.27 11.37 13.96 0.15 0.10 55.12 0.04 0.00 0.00 94.42 259M-21 1.63 0.86 1.81 0.12 13.01 2.05 2.39 71.85 0.08 0.00 0.00 93.80 259M-22 0.47 0.24 1.19 0.11 0.15 0.03 0.01 87.00 0.00 0.00 0.00 89.21 259M-23 0.09 0.66 0.10 0.12 13.26 16.44 1.97 70.08 0.21 0.00 0.00 102.94 259M-24 0.04 0.53 0.21 0.13 15.19 0.00 3.46 72.08 0.08 0.00 0.00 91.72 259M-25 0.04 0.66 1.56 1.41 16.31 0.04 0.21 73.05 0.05 0.00 0.00 93.32 259M-26 4.61 6.43 0.41 0.07 9.66 0.09 0.76 70.93 0.00 0.00 0.00 92.96 259M-27 0.77 2.42 5.33 4.21 8.25 0.08 0.33 72.78 0.07 0.00 0.00 94.24 259M-3 3.07 2.20 0.09 0.17 13.52 . 1.68 0.85 71.07 0.15 0.00 0.00 92.80 259M-30 0.21 0.89 0.05. 0.22 10.70 17.54 2.73 61.61 0.24 0.00 0.00 94.19 259M-33 0.13 0.10 0.28 0.02 1.57 0.01 0.00 87.97 0.00 0.00 0.00 90.08 259M-34 0.09 0.05 0.02 0.02 0.07 0.00 0.01 93.37 0.00 0.00 0.00 93.63 259M-35 0.54 0.19 1.58 0.09 0.08 0.00 0.05 87.56 0.00 0.00 0.00 90.10 259M-36 0.07 0.02 0.00 .0.04 0.03 0.01 0.00 92.64 0.02 0.00 0.00 92.84 259M-37 0.07 0.90 0.39 0.18 6.06 0.00 0.46 85.55 0.02 0.00 0.00 93.62 259M-39 0.99 0.76 7.67 5.34 8.04 0.04 0.18 70.63 0.03 0.05 0.00 93.73 259M-4 0.55 0.76 1.18 0.43 14.28 0.00 2.87 68.67 0.00 0.00 0.00 88.74 259M-40 10.27 4.41 0.63 0.06 14.64 0.02 0.81 62.36 0.07 0.00 0.00 93.26 259M-41 0.34 0.16 1.35 0,07 0.06 0.08 0.00 88.27 0.00 0.00 0.00 90.33 259M-44 0.08 0.58 5.65 5.06 8.72 0.01 0.29 72.18 0.07 0.00 0.00 92.65 259M-45 0.17 1.71 0.49 0.14 16.97 0.12 1.86 72.93 0.00 0.00 0.00 94.38 259M-46 0.06 0.01 0.02 0.02 0.02 0.01 0.05 92.71 0.00 0.00 0.01 92.91 259M-47 0.46 1.03 0.28 0.12 10.00 20.23 2.92 58.74 0.15 0.00 0.00 93.93 259M-48 0.46 1.01 2.59 1.57 12.26 0.39 1.24 73.67 0.08 0.00 0.00 93.27 259M-49 0.12 0.53 0.17 0.26 9.45 1.16 1.70 79.11 0.10 0.00 0.00 92.60 259M-6 0.07 0.03 0.08 0.04 0.01 0.00' 0.00 87.83 0.00 0.00 0.00 88.07 259M-7 0.09 0.01 0.02 0.00 0.02 0.05 0.01 93.46 0.00 0.00 0.02 93.66 259M-8 0.33 0.84 0.22 0.22 12.66 15.79 2.83 61.66 0.21 0.00 0.00 94.77 1 9 Grains were determined to be magnetite i f they contained less than 30% T i 0 2 and less than 30% C r 2 0 3 . Thus, analyses in this table include those for titanomagnetite and spinel. Sample number indicates the depth of the sample. Samples at 108 and 130 m are autolithic volcaniclastic kimberlite breccia. Samples at 203 and 248 m are heterolithic volcaniclastic kimberlite breccia. Samples at 251 and 259 m are lithic breccia. F means that the grains were from the Frantz separate, and M means the grain were separated using a magnet. 128 Appendix D: Compositional analysis of chromite grains within the Anuri kimberlite Table D. l : Compositional analyses obtained using the Electron Microprobe at the University of British Columbia, for chromite grains separated from the Anuri kimberlite 20. Sample MgO Al203 Si02 CaO Ti02 V205 Cr203 MnO Fe203 NiO Nb205 Total 108F 6.966 2.378 0.019 0.000 1.140 0.248 45.599 0.446 40.487 0.198 0.000 97.482 108F 10.049 8.982 0.009 0.032 0.028 0.289 57.448 0.244 22.296 0.069 0.006 99.500 108F 10.757 6.373 0.060 0.011 0.296 0.283 62.216 0.116 19.429 0.076 0.000 99.618 108M 9.575 6.812 0.036 0.053 0.144 0.267 52.898 0.215 27.871 0.130 0.000 98.001 108M 9.292 6.475 0.026 0.010 0.132 0.210 57.083 0.225 25.580 0.067 0.000 99.101. 108M 10.362 9.152 0.000 0.005 0.088 0.272 56.804 0.139 21.857 0.123 0.000 98.824 108M 7.854 5.196 0.001 0.008 0.475 0.167 48.456 0.281 34.127 0.239 0.035 96.839 130F 6.966 2.378 0.019 0.000 1140 0.248 45.599 0.446 40.487 0.198 0.000 97.482 130F 10.049 8.982 0.009 0.032 0.028 0.289 57.448 0.244 22.296 0.069 0.006 99.500 130F 10.757 6.373 0.060 0.011 0.296 0.283 62.216 0.116 19.429 0.076 0.000 99.618 130M 7.020 1.778 0.040 0.000 0.784 0.178 51.801 0.340 35.682 0.101 0.000 97.724 130M 10.024 4.886 0.070 0.015 3.257 0.000 52.265 0.242 27.159 0.203 0.000 98.156 203F-25 10.178 9.625 0.000 0.009 0.249 0.154 55.743 0.210 23.697 0.032 0.000 99.896 203M-11 7.577 2.547 0.027 0.007 0.688 0.185 48.274 0.338 38.726 0.139 0.000 98.508 203M-12 10.197 9.750 0.025 0.020 0.056 0.278 58.690 0.099 21.325 0.068 0.100 100.624 203M-18 10.101 9.150 0.031 0.021 0.075 0.237 58.865 0.214 21.781 0.046 0.000 100.519 203M-19 9.986 7.220 0.004 0.000 0.060 0.245 59.840 0.140 21.970 0.009 0.000 99.488 203M-20 12.601 18.084 0.015 0.019 0.176 0.190 50.255 0.106 18.662 0.094 0.000 100.216 203M-21 9.683 8.312 0.000 0.000 0.060 0.264 57.660 0.178 22.932 0.066 0.059 99.220 203M-31 9.295 6.729 0.016 0.000 0.143 0.295 57.357 0.215 25.823 0.050 0.000 99.925 203M-32 10.241 9.108 0.061 0.008 0.023 0.349 58.419 0.092 22.382 0.101 0.000 100.785 203M-37 8.096 1.066 0.005 0.020 0.463 0.099 63.127 0.270 26.048 0.052 0.081 99.342 203M-41 8.832 3.361 0.027 0.000 0.290 0.189 61.566 0.308 25.966 0.064 0.046 100.700 203M-43 9.497 7.314 0.051 0.000 0.149 0.193 57.799 0.206 23.617 0.072 0.000 98.899 203IVM7 7.029 2.349 0.023 0.010 0.905 0.229 46.309 0.305 40.761 0.215 0.000 98.176 203M-50 9.866 7.294 0.000 0.001 0.080 0.247 59.367 0.162 22.063 0.002 0.006 99.088 248F-3 10.058 9.831 0.012 0.002 0.103 0.249 56.784 0.216 21.881 0.043 0.000 99.183 248M-11 10.815 7.701 0.047 0.002 0.590 0.110 . 57.708 0.139 21.536 0.063 0.000 98.711 248M-15 10.697 13.104 0.036 0.020 0.185 0.214 49.706 0.170 23.963 0.131 0.000 98.227 248M-2 6.285 1.586 0.017 0.020 1.398 0.073 43.638 0.280 43.633 0.174 0.000 97.187 248M-23 9.478 7.639 0.027 0.017 0.057 0.346 56.890 0.205 23.582 0.052 0.000 98.293 248M-29 11.580 11.819 0.045 0.013 0.021 0.060 58.440 0.161 16.717 0.056 0.000 98.911 248M-30 8.828 5.393 0.000 0.023 0.276 0.134 57.293 0.219 25.798 0.113 0.000 98.079 248M-34 8.680 2.915 0.004 0.000 0.316 0.239 61.298 0.211 25.269 0.080 0.012 99.024 248M-4 9.466 7.852 0.030 0.016 0.081 0.269 57.270 0.136 23.986 0.124 0.000 99.230 248M-41 9.982 9.134 0.039 0.003 0.113 0.283 55.793 0.127 22.635 0.112 0.041 98.289 248M-42 11.662 11.668 0.000 0.000 0.003 0.058 59.214 0.145 16.765 0.033 0.000 99.548 248M-5 11.135 15.531 0.000 0.000 0.072 0.214 53.422 0.165 19.089 0.056 0.054 99.737 251F-17 10.798 4.788 0.043 0.046 5.863 0.000 47.202 0.286 30.142 0.198 0.058 99.423 251F-21 10.568 3.623 0.049 0.014 5.750 0.000 48.053 0.239 31.068 0.219 0.111 99.694 251F-30 10.228 12.262 0.078 0.014 0.262 0.175 44.420 0.214 31.242 0.153 0.000 99.048 251F-5 10.650 4.219 0.036 0.024 5.541 0.000 45.555 0.208 32.406. 0.105 0.000 98.757 251F-6 10.372 2.834 0.036 0.023 9.821 0.000 34.691 0.348 39.042 0.149 0.000 97.315 251M-13 12.020 13.714 0.035 0.030 0.367 0.302 55.095 0.263 18.927 0.089 0.136 100.977 129 Sample MgO A l 2 0 3 S i 0 2 CaO T i0 2 V 2 0 5 C r 2 0 3 MnO F e 2 0 3 NiO N b 2 0 5 Total 251M-19 8.516 3.263 0 107 0 053 7 292 0 000 38 267 0 925 38 736 0 078 0 000 97.238 251M-27 12.516 18.058 0 114 0 004 0 103 0 139 42 211 0 205 26 319 0 178 0 000 99.847 251M-28 10.945 8.799 0 000 0 004 0 178 0 248 61 848 0 109 17 718 0 055 0 082 99.998 251M-4 11.161 9.387 0 017 0 028 0 184 0 223 60 959 0 108 17 640 0 081 0 006 99.791 259F-13 9.924 4.915 0 276 3 076 5 494 0 000 42 684 0 292 27 980 0 194 0 000 94.836 259F-15 10.102 14.493 0 023 0 000 0 201 0 155 45 106 0 246 28 421 0 079 0 054 98.880 259F-21 9.875 7.758 0 021 0 001 0 132 0 186 57 865 0 237 24 276 0 126 0 059 100.542 259F-23 7.489 1.444 0 024 0 000 0 299 0 182 59 601 0 407 29 315 0 087 0 012 98.858 259F-34 11.091 5.911 0 067 0 040 4 240 0 000 49 519 0 211 27 709 0 183 0 000 98.970 259F-45 7.573 1.438 0 026 0 620 0 433 0 249 57 846 0 283 29 564 0 081 0 029 98.142 259F-49 11.234 5.849 0 058 0 263 6 256 0 000 40 398 0 428 31 955 0 153 0 041 96.635 259M-19 8.655 3.194 0 043 0 039 0 092 0 287 60 467 0 128 26 122 0 060 0 035 99.122 259M-28 11.749 3.153 0 037 0 153 3 578 0 000 52 174 0 255 26 800 0 258 0 082 98.239 259M-29 10.324 10.821 0 002 0 004 0 098 0 296 56 838 0 181 20 680 0 046 0 000 99.291 259M-31 9.794 9.358 0 023 0 000 0 082 0 320 57 092 0 146 23 044 0 114 0 053 100.028 259M-9 8.142 3.807 0 060 0 121 4 542 0 000 43 276 0 577 36 409 0 106 0 000 97.041 Grains were classified as chromite i f their analyses indicated C r 2 0 3 contents greater than 40%. Sample number indicates the depth of the sample. Samples at 108 and 130 m are autolithic volcaniclastic kimberlite breccia. Samples at 203 and 248 m are heterolithic volcaniclastic kimberlite breccia. Samples at 251 and 259 m are lithic breccia. F means that the grains were from the Frantz separate, and M means the grain were separated using a magnet. 130 Appendix E; Methodology for Measurement of Physical Properties Magnetic susceptibility was measured using a KT-9 Kappameter instrument from Exploranium Radiation Detection Systems. Density was measured by weighing core pieces dry and then suspended in water. Density was calculated using equation 2.1. w J — w Where Wdry is the mass of the dry sample [g], w w e t is the mass of the sample emerged in water [g], and p is the density of the sample [g/cm3]. 131 Appendix F: Physical Property and Grade Data for the LT508-1 Drillhole Table F . l : Summary of physical properties and diamond content indicators for the LT508-1 drill core studied in this thesis. Lithological abbreviations are: AVKB = autolithic volcaniclastic kimberlite breccia; HVKB = heterolithic volcaniclastic kimberlite breccia; LB = lithic breccia. Depth (m) Magnetic Susceptibility (1Cr3 SI) Average Standard Deviation Density (g/cm3) Stones/ 100kg Macrocryst : microcryst Lithology 95 3.7 0.6 2.46 200 0.05 AVKB 100 3.9 0.6 2.49 130 0.08 AVKB 105 4.6 0.7 2.46 230 0.05 AVKB 111 22.0 1.3 2.43 93 0.13 AVKB 115 7.6 0.9 2.48 174 0.07 AVKB 120 8.4 0.9 2.46 227 0.05 AVKB 129 4.6 0.7 2.46 184 0.06 AVKB 134 4.6 0.7 2.48 165 0.14 AVKB 139 4.0 0.6 2.50 304 0.15 AVKB 144 6.5 0.8 2.50 157 0.21 AVKB 148 8.1 0.9 2.46 84 0.14 AVKB 172 8.0 0.9 2.44 135 0.08 HVKB 176 8.0 0.9 2.43 147 0.07 HVKB 180 11.2 1.0 2.42 140 0.17 HVKB 190 7.5 0.9 2.42 160 0.13 HVKB 202 11.0 1.0 2.39 95 0.11 HVKB 206 9.5 1.0 2.40 120 0.09 HVKB 210 16.2 1.2 2.40 126 0.08 HVKB 215 17.4 1.2 2.43 137 0.27 HVKB 229 8.6 0.9 2.44 250 0.04 HVKB 233 10.1 1.0 2.46 216 0.05 HVKB 239 24.0 1.4 2.60 105 0.10 HVKB 251 8.5 1.0 2.58 69 0.17 LB 256 9.2 1.0 2.47 110 0.10 LB 132 Appendix G: Physical property and grade data for the hypabyssal kimberlite ofLT508-4 drillhole Table C . l : Summary of physical properties and diamond content indicators for the LT508-4 drillcore that sampled the hypabyssal kimberlite of the eastern lobe. Data provided by Kennecott Exploration. Depth (m) Magnetic Susceptibility (10"3SI) Density (g/cm3) Stones/ 100kg Macrocryst Microcryst Lithology 294 44.1 2.33 52 0.00 HK 298 31.2 2.33 6 0.00 HK 301 33.0 2.28 121 0.13 HK 304 30.3 2.31 110 0.07 HK 307 4.4 2.29 87 0.00 HK 310 16.2 2.30 62 0.00 HK 313 12.4 2.29 109 0.08 HK 316 10.1 2.34 101 0.00 HK 319 3.6 2.34 82 0.00 HK 322 14.2 2.31 88 0.00 HK 325 7.6 2.32 62 0.17 HK 133 Appendix H: Physical Property Distributions of Anuri Kimberlite Lithologies Physical property measurements from the LT508-1 drillhole for the three kimberlite lithologies were characterized statistically using histograms (Figure H. 1). Differences in physical properly characteristics between lithologies likely reflect variations in both primary and secondary geological processes that formed the different rock types and perhaps concentrated diamonds. Density distributions of autolithic and heterolithic volcaniclastic kimberlite breccia samples are best described by normal distributions. Both lithologies have slightly different averages that overlap considerably when considering the one-sigma standard deviation. The two lithologies are mineralogically and texturally similar, hence they have comparable physical properties. The susceptibility distribution of the autolithic volcaniclastic kimberlite breccia samples does not appear to be in accordance with either a normal or lognormal distribution. Conversely, the susceptibility distribution of the heterolithic volcaniclastic kimberlite breccia samples appears to follow a skewed lognormal distribution. Susceptibility distributions of both the heterolithic and autolithic volcaniclastic kimberlite breccia lithologies are potentially lognormally distributed, as are most susceptibility distributions, and this study's relatively small data set is not sufficiently representative. The nature of the physical property distributions of the lithic breccia similarly cannot be assessed, due to the limited data. 134 A U T O L I T H I C V O L C A N I C L A S T I C KIMBERLITE BRECCIA N=16 mean=6 951 std dev=4 402243 N=16 mean=0.7906525 std dev=0.1988328 N=16 mean=2 463687 std dev=2 293096E-O2 10 20 MS 3 2.4 2.5 2.6 2.7 Log MS Density HETEROLITHIC VOLCANICLASTIC KIMBERLITE BRECCIA N=14 mean=10.25478 std dev=3 027081 N=14mean=0 9963104 std dev=0 1118779 - 1 1 1 I | 1 1 1 N=14 mean=2.424857 std dev=2.403798E-02 1 r LITHIC BRECCIA N=5 mean=14.6726 std dev=7 747674 4 i i r 5 0.7 0.9 1.1 1.3 Log MS N=5 mean=1 118917std dev=02243707 4 i 1 1 1 1 1 1 r 3 2.4 2.5 2.6 2.7 Density N=5 mean=2 5498 std dev=6.564831 E-02 2.5 2.6 2.7 Density Figure H. l : Histograms (frequency along vertical axis) for the autolithic volcaniclastic kimberlite breccia (top row), heterolithic volcaniclastic kimberlite breccia (middle row) and lithic breccia (bottom row), with the magnetic suceptibility distribution on the far left (10 ' SI), the logarithm of susceptibility in the middle column, and density in the far right column. The black lines are the normal distributions calculated by Igpet for the data, with the number of data points (N), the mean and standard deviation (std dev) showing along the top of each diagram, as calculated for normally distributed data. 135 Appendix I; Geologic and Geophysical Properties used for Covariance and Principle Component Analysis Physical, geologic and grade properties were assessed on a 1 m scale, which was the scale of data used for the "fine-scale" analysis. The "coarse-scale" data was this data averaged over the crushing intervals of the grade indicators, represented in this table as depth intervals over which stones/100 kg and macrocrystmicrocryst (mac:mic) do not vary. Lithologies are represented as such: 1 for autolithic volcaniclastic kimberlite breccia, 2 for heterolithic volcaniclastic kimberlite breccia, 3 for lithic breccia. Qualitative geologic properties in this table were quantified on a relative scale, including degree of fragmentation of core (fragmental), bedding, sorting, alteration and veining. Grain Size -Xenolith content Depth (m) Mag. Sus. (103SI) Density (g/cm3) Stones/ 100kg "a . C : Lith Mic Frag-mental Bedding Sorting Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 92 4.07 2.46 170 0.06 1 2 0 5 20 25 35 20 0 0 70 10 70 20 3 2 93 3.65 2.46 170 0.06 1 4 0 3 10 10 45 25 5 0 70 30 60 10 3 0 94 3.50 2.46 170 0.06 1 2 0 3 15 20 30 25 5 0 70 20 55 25 3 2 95 3.69 2.49 200 0.05 1 2 1 3 20 20 25 30 5 0 60 10 60 30 3 0 96 4.03 2.46 200 0.05 1 2 0 2 25 15 25 30 5 0 60 5 55 40 3 0 97 3.89 2.52 200 0.05 1 3 0 2 15 15 25 35 10 0 70 30 45 25 3 2 98 4.61 2.47 200 0.05 1 3 0 3 20 20 35 25 0 0 60 10 55 35 3 2 99 2.57 2.50 200 0.05 1 3 0 4 20 15 35 25 5 0 60 5 60 35 1 2 100 3.37 2.52 130 0.08 1 2 1 3 17 20 25 30 8 0 70 10 55 35 1 0 101 6.57 2.42 130 0.08 1 4 0 3 15 30 30 25 0 0 55 10 70 20 1 2 102 5.61 2.45 130 .0.08 1 3 0 4 15 25 35 25 0 0 60 20 70 10 1 2 103 4.24 2.45 130 0.08 1 2 0 5 20 30 40 10 0 0 55 20 60 20 1 0 104 5.05 2.47 130 0.08 1 3 0 3 15 20 25 25 5 0 60 10 60 30 1 2 105 3.24 2.41 230 0.05 1 4 0 3 15 30 30 25 0 0 50 10 65 25 1 2 106 3.92 2.44 230 0.05 1 3 0 5 20 25 30 20 5 0 60 10 60 30 1 2 107 4.34 2.38 230 0.05 1 3 0 3 20 25 30 20 5 0 65 10 60 30 1 0 108 39.03 2.46 230 0.05 1 4 0 3 15 25 30 20 5 5 70 25 55 20 1 2 109 2.80. 2:47 230 0.05 1 2 0 3 18 25 30 15 7 5 65 10 50 40 1 2 110 82.08 2.44 230 0.05 1 3 0 4 20 25 35 20 0 0 65 5 70 30 2 111 4.27 2.47 93 0.13 1 3 0 3 15 20 35 30 0 0 60 15 65 20 1 2 112 3.38 2.44 93 0.13 1 3 0 4 20 20 40 20 0 0 60 10 70 20 1 2 u> Grain Size Xenolith content Depth (m) Mag. Sus. (103SI) Density (g/cm3) Stones/ 100kg "a c : Lith Mic Frag-mental Bedding Sorting Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 113 2.90 2.46 93 0.13 1 2 0 4 20 20 30 30 0 0 60 10 80 10 1 0 114 3.01 2.52 93 0.13 1 3 0 3 15 25 30 20 10 0 65 10 55 35 3 0 115 23.10 2.45 174 0.07 1 3 0 . 3 15 25 25 30 5 0 65 10 50 . 40 1 2 116 3.68 2.49 174 0.07 1 2 0 5 20 25 30 25 0 0 60 5 80 15 3 2 117 9.30 2.46 174 0.07 1 2 1 4 20 20 25 25 0 0 70 5 85 10 3 2 118 2.18 2.47 174 0.07 1 3 0 4 20 20 40 20 0 0 65 10 80 10 3 2 119 3.57 2.46 174 0.07 1 3 1 3 15 20 40 20 5 0 70 10 80 10 1 2 120 3.46 2.46 227 0.05 1 3 0 3 20 20 40 15 5 0 60 5 85 10 3 2 121 3.39 2.46 227 0.05 1 1 0 4 20 30 35 15 0 0 50 10 80 10 1 0 122 2.19 2.46 227 0.05 1 2 1 5 20 15 40 20 5 0 70 5 75 20 1 0 123 5.20 2.46 227 0.05 1 3 1 5 15 25 30 25 5 0 75 25 50 25 1 0 124 3.94 2.47 227 0.05 1 2 0 3 15 25 40 15 0 5 60 10 60 30 1 0 125 5.43 2.47 227 0.05 1 3 0 2 15 20 25 30 10 0 60 20 65 15 3 0 126 2.96 2.45 227 0.05 1 3 1 3 20 15 35 30 0 0 75 20 60 20 3 0 127 3.81 2.47 227 0.05 1 2 0 3 20 20 30 25 5 0 65 20 65 15 1 2 128 6.16 2.45 227 0.05 1 3 0 3 20 15 45 20 0 0 50 20 65 15 3 2 129 6.33 2.47 184 0.06 1 3 0 4 20 20 30 30 0 0 60 10 65 25 2 0 130 3.71 2.48 184 0.06 1 3 0 3 15 20 35 30 0 0 60 15 60 25 1 2 131 5.06 2.52 184 0.06 1 2 0 3 15 30 30 15 10 0 55 25 55 20 2 2 132 3.69 2.46 184 0.06 1 2 0 2 20 10 30 15 0 15 60 20 60 20 1 2 133 2.94 2.49 184 0.06 1 2 0 3 20 20 40 20 0 0 60 10 70 20 1 2 134 5.47 2.49 165 0.14 1 3 0 5 20 20 35 20 5 0 60 15 60 25 1 0 135 4.68 2.51 165 0.14 1 1 0 3 20 20 30 30 0 0 50 10 70 20 2 0 136 4.08 2.49 165 0.14 1 3 0 4 . 20 20 35 25 0 0 50 10 60 30 1 0 137 3.05 2.50 165 0.14 1 3 0 4 25 20 30 25 0 0 70 15 70 15 2 0 138 3.35 2.53 165 0.14 1 2 1 4 25 15 25 20 15 0 60 30 55 15 2 0 139 3.68 2.46 304 0.15 1 3 1 4 20 30 40 10 0 0 50 10 60 30 3 2 140 9.16 2.51 304 0.15 1 2 1 3 15 15 35 30 5 0 65 10 60 30 3 0 141 4.67 2.50 304 0.15 1 2 2 3 . 15 20 35 30 0 0 60 10 70 20 3 3 142 8.20 2.53 304 0.15 1 2 0 3 20 15 35 30 0 0 70 20 55 25 3 0 143 4.67 2.50 304 0.15 1 3 0 3 20 20 35 25 0 0 70 10 75 15 3 2 144 4.13 2.45 157 0.21 1 2 1 4 20 25 35 20 0 0 70 10 65 25 3 2 145 21.98 2.48 157 0.21 1 2 0 3 20 20 30 25 0 5 75 20 60 20 3 2 146 3.32 2.46 157 0.21 1 3 0 3 15 20 25 30 10 0 80 25 60 15 3 2 147 5.21 2.45 157 0.21 1 3 1 3 15 25 35 25 0 0 80 10 60 30 3 2 148 6.44 2.48 84 0.14 1 3 1 3 20 20 40 20 0 0 65 10 70 20 3 2 Grain Size Xenolith content Depth (m) Mag. Sus. (lO^SI) Density (g/cm3) Stones/ 100kg Mac: Mic Lith Frag-mental Bedding Sorting Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 149 6.30 2.46 84 0.14 . 1 2 1 3 20 20 40 20 0 0 70 15 65 20 1 1 150 4.45 2.46 84 0.14 1 2 0 3 15 15 35 35 0 0 70 10 50 40 2 0 151 4.33 2.44 84 0.14 1 3 0 3 15 30 30 25 0 0 65 5 55 40 1 2 152 5.27 2.45 84 0.14 1 2 0 3 20 25 25 15 15 0 60 10 60 30 2 2 153 6.25 2.45 84 0.14 1 3 1 3 15 20 30 30 5 0 70 15 70 15 1 2 154 5.36 2.43 84 0.14 1 2 0 3 20 30 30 20 0 0 70 10 70 20 2 2 155 5.01 2.44 84 0.14 1 2 0 3 15 20 35 30 0 0 75 5 .80 15 1 0 156 14.27 2.44 84 0.14 1 2 0 3 20 25 30 25 0 0 75 5 85 10 2 0 157 6.00 2.44 84 0.14 1 3 0 3 15 25 30 30 0 0 75 5 75 20 2 2 158 6.69 2.44 84 0.14 1 2 0 3 10 25 35 25 5 0 75 10 65 25 1 0 159 5.83 2.46 84 0.14 1 2 1 3 20 20 30 30 0 0 75 5 70 25 2 2 160 2.76 2.45 84 0.14 1 3 1 3 20 25 35 20 0 0 65 10 65 25 1 0 161 14.76 2.46 84 0.14 1 3 1 4 25 30 25 20 0 0 70 5 80 15 1 2 162 6.09 2.47 84 0.14 1 2 0 4 20 35 25 20 0 0 75 10 60 30 2 0 163 8.93 2.46 84 0.14 1 2 0 5 25 35 25 15 0 0 60 10 65 25 3 0 164 5.46 2.45 84 0.14 1 3 0 5 20 30 35 15 0 0 60 5 75 20 3 0 165 8.01 2.37 84 0.14 1 3 0 5 20 35 30 15 0 0 70 15 65 20 3 2 166 7.86 2.40 84 0.14 1 2 0 5 25 30 30 15 0 0 75 15 70 15 3 0 167 9.38 2.45 84 0.14 1 3 1 4 20 30 35 15 0 0 70 10 70 20 2 2 168 8.97 2.44 84 0.14 1 2 1 4 15 30 35 20 0 0 75 20 65 15 2 2 169 5.69 2.45 84 0.14 2 1 0 4 15 30 40 15 0 0 70 20 70 10 2 2 170 11.60 2.44 84 0.14 2 2 0 4 25 35 30 15 0 0 70 15 75 10 2 2 171 8.49 2.42 135 0.08 2 2 0 4 25 30 35 15 0 0 75 10 80 10 1 0 172 7.87 2.42 135 0.08 2 2 0 3 20 35 30 15 0 0' 70 10 80 10 2 2 173 10.73 2.42 135 0.08 2 3 0 3 30 30 30 10 0 0 60 2 88 10 3 0 174 7.53 2.44 135 0.08 2 2 0 4 30 35 28 7 0 0 55 3 92 5 3 2 175 8.04 2.44 135 0.08 2 2 1 4 30 30 30 10 0 0 55 3 87 10 3 2 176 5.37 2.45 147 0.07 2 3 0 3 25 30 35 10 0 0 65 3 90 7 3 2 177 18.68 2.47 147 0.07 2 3 0 3 25 30 25 13 7 0 55 3 87 10 3 0 178 10.00 2.41 147 0.07 2 3 0 4 30 35 30 5 0 0 40 1 95 4 3 0 179 7.20 2.39 147 0.07 2 3 0 3 20 35 25 20 0 0 65 1 92 7 3 0 180 7.60 2.41 140 0.17 2 3 0 3 30. 35 20 15 . 0 0 60 2 88 10 3 0 181 6.07 2.40 140 0.17 2 3 0 4 35 30 25 10 0 0 50 0 97 3 3 0 182 7.00 2.42 140 0.17 2 3 0 5 40 30 20 10 0 0 30 5 85 10 3 0 183 8.13 2.44 140 0.17 2 3 0 3 30 35 25 10 0 0 60 1 95 4 3 0 184 8.48 2.31 140 0.17 2 2 0 4 35 35 23 7 0 0 55 0 95 5 3 0 0 0 Depth (m) Mag. Sus. (103 SI) Density (g/cm3) Stones/ 100kg Mac: Mic Lith Frag-mental Bedding Sort 185 9.47 2.408 2.41 140 2 2 0 4 186 6.87 2.403 2.40 140 2 3 0 4 187 9.11 2.432 2.43 140 2 3 0 3 188 7.48 2.437 2.44 140 2 2 0 3 189 8.62 2.441 2.44 140 2 2 0 3 190 6.02 2.41 2.41 150 2 2 1 4 191 7.55 2.459 2.46 160 1 3 1 3 192 6.25 2.403 2.40 160 1 3 1 2 193 14.62 2.426 2.43 160 1 2 1 3 194 6.90 2.487 2.49 160 1 2 1 3 195 11.33 2.339 2.34 160 1 2 1 2 196 8.07 2.407 2.41 160 1 3 0 3 197 17.73 2.453 2.45 160 1 2 0 3 198 8.72 2.399 2.40 160 1 3 0 2 199 8.04 2.394 2.39 160 1 3 1 3 200 6.87 2.352 2.35 160 1 3 0 3 201 6.87 2.407 2.41 160 2 2 1 3 202 11.15 2.349 2.35 95 2 2 1 3 203 9.93 2.409 2.41 95 2 2 0 3 204 8.91 2.442 2.44 95 2 2 0 3 205 8.78 2.421 2.42 95 2 2 0 3 206 5.71 2.387 2.39 120 2 3 1 3 207 7.51 2.433 2.43 120 2 3 0 3 208 53.64 2.349 2.35 120 2 2 1 3 209 11.82 2.397 2.40 120 2 2 0 3 210 5.38 2.402 2.40 126 2 2 0 2 211 18.76 2.412 2.41 126 2 2 0 3 212 8.31 2.514 2.51 126 2 3 0 3 213 34.11 2.454 2.45 126 2 2 0 5 214 9.35 2.448 2.45 126 2 2 0 3 215 9.78 2.432 2.43 137 2 3 0 2 216 8.96 2.450 2.45 137 2 3 1 2 217 7.63 2.424 2.42 137 2 2 0 2 218 6.70 2.478 2.48 137 2 2 0 3 219 7.42 2.419 2.42 137 2 2 1 2 220 8.58 2.440 2.44 137 2 3 1 3 Grain Size Xenolith content Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 25 35 30 10 0 0 70 3 90 7 3 0 20 35 35 10 0 0 75 2 95 3 3 0 20 35 35 10 0 0 75 5 90 5 3 0 15 35 40 10 0 0 75 2 95 3 3 0 20 35 30 15 0 0 70 2 95 3 3 0 20 37 28 15 0 0 70 1 90 9 3 0 20 40 25 15 0 0 70 1 90 9 4 0 20 30 20 10 0 20 75 2 93 5 4 0 20 30 35 15 0 0 75 2 95 3 4 2 23 32 30 15 0 0 70 2 93 5 4 0 20 35 20 15 0 10 70 0 97 3 4 0 20 50 20 10 0 0 70 2 95 5 4 0 20 50 20 10 0 0 70 3 94 5 4 0 15 35 25 15 0 10 80 2 88 10 4 0 15 30 30 15 0 0 80 2 95 3 4 0 15 35 30 10 0 0 75 2 95 3 4 2 20 40 30 10 0 0 60 0 95 5 5 0 25 40 20 15 0 0 70 5 90 5 5 0 25 40 20 15 0 0 70 2 95 3 4 0 15 45 25 15 0 0 70 2 93 5 5 0 15 40 30 15 0 0 70 5 90 5 5 2 15 40 30 15 0 0 70 2 93 5 4 0 20 40 30 10 0 0 50 3 92 5 5 2 15 .25 40 12 8 0 70 2 93 5 5 2 15 35 35 15 0 0 80 5 85 10 4 0 15 35 35 15 10 0 80 5 87 8 4 0 20 35 30 15 0 0 70 2 95 3 4 0 20 35 25 20 0 0 80 3 92 5 4 0 20 40 30 10 0 0 60 2 95 3 3 0 18 25 30 15 12 0 65 2 95 3 3 2 15 30 35 15 5 0 65 1 95 4 4 2 15 30 35 20 0 0 75 2 93 5 4 0 20 30 30 15 5 0 70 0 97 3 4 0 20 35 22 13 0 10 75 5 90 5 4 0 20 30 25 10 0 15 75 10 85 5 5 0 20 35 30 15 0 0 70 5 90 5 5 0 Grain Size Xenolith content Depth (m) Mag. Sus. (10"3SI) Density (g/cm3) Stones/ 100kg Mac: Mic Lith Frag-mental Bedding Sorting Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 221 12.90 2.46 137 0.27 2 3 0 3 20 30 35 15 0 0 70 5 93 2 5 2 222 11.23 2.47 137 0.27 2 3 0 2 15 35 25 20 5 0 80 5 90 5 5 0 223 10.33 2.44 137 0.27 2 2 1 3 20 35 25 20 0 0 75 5 92 3 5 0 224 12.00 2.45 137 0.27 2 3 0 2 20 30 30 10 10 0 80 5 90 5 5 0 225 6.76 2.43 137 0.27 2 3 0 3 20 35 35 . 10 0 0 80 3 94 3 5 0 226 8.93 2.45 137 0.27 2 2 0 3 20 40 30 10 0 0 65 5 90 5 5 2 227 8.01 2.43 137 0.27 2 3 1 3 30 30 35 5 0 0 60 5 90 5 5 0 228 7.32 2.44 137 0.27 2 2 1 5 25 30 30 10 5 0 50 0 97 3 5 0 229 10.53 2.46 250 0.04 2 3 1 3 25 35 25 15 0 0 60 5 90 5 5 0 230 21.10 2.47 250 0.04 2 3 1 3 25 40 20 15 0 0 65 5 85 10 3 0 231 7.73 2.48 250 0.04 2 3 1 3 20 40 25 15 0 0 70 5 85 10 3 0 232 7.18 2.53 250 0.04 2 3 1 3 20 40 30 10 0 0 85 5 85 10 . 3 0 233 0.31 2.50 216 0.05 2 3 1 3 15 25 25 15 20 0 85 3 90 7 3- 2 234 6.54 2.56 216 0.05 2 3 1 3 25 30 30 15 0 0 85 5 80 15 3 2 235 49.85 2.67 216 0.05 2 2 0 3 20 40 35 15 0 0 80 3 90 7 3 2 236 5.45 2.68 216 0.05 2 2 0 2 8 7 5 5 0 75 90 0 100 0 5 0 237 56.27 2.65 216 0.05 2 2 0 2 15 10 25 10 15 25 85 10 90 0 4 0 238 7,18 2.69 216 0.05 2 3 0 2 10 15 25 15 0 35 90 10 87 3 4 0 239 83.68 2.59 105 0.10 2 4 0 1 3 3 8 9 0 77 97 0 100 0 4 0 240 0.19 2.60 105 0.10 2 3 0 1 15 10 25 20 10 20 85 2 95 3 4 2 241 14.33 2.59 105 0.10 2 2 0 1 10 15 15 25 5 30 90 0 97 3 5 0 242 73.10 2.65 105 0.10 2 3 0 2 20 15 25 10 0 30 70 0 95 5 5 2 243 1.35 2.48 105 0.10 2 2 0 2 10 15 20 20 10 25 95 0 100 0 3 2 244 33.20 2.59 • 105 0.10 2 3 0 2 15 15 15 10 10 35 85 5 85 10 5 2 245 11.50 2.56 105 0.10 2 3 0 2 25 25 25 15 0 10 70 0 95 5 4 2 246 13.27 2.66 105 0.10 2 2 0 3 28 30 27 15 0 0 60 0 95 5 4 2 247 0.33 2.58 105 0.10 2 4 0 1 5 15 10 35 25 10 95 0 100 0 2 0 248 9.39 2.53 105 0.10 2 2 0 1 5 15 20 25 20 15 90 5 90 5 .4 2 249 20.03 2.50 105 0.10 2 2 0 3 15 20 25 30 0 0 80 5 85 10 5 2 250 12.75 2.48 105 0.10 2 2 1 3 30 35 20 15 0 0 50 5 80 15 3 0 251 7.42 2.47 69 0.17 3 2 0 5 30 40 20 10 0 0 40 10 80 10 3 2 252 8.32 2.49 69 0.17 3 1 0 4 25 40 20 15 0 0 40 5 85 10 4 0 253 9.83 2.43 69 0.17 3 2 0 3 15 15 30 20 20 0 85 10 75 15 5 2 254 6.76 2.46 69 0.17 3 1 0 3 15 20 25 30 0 0 85 10 80 10 6 0 255 7.76 2.47 69 0.17 3 1 0 3 10 30 35 25 0 0 90 10 80 10 6 0 256 7.57 2.55 110 0.10 3 2 0 3 15 20 30 25 10 0 80 10 80 10 6 0 © Grain Size Xenolith content Depth (m) Mag. Sus. (10"3SI) Density (g/cm3) Stones/ 100kg Mac: Mic Lith Frag-mental Bedding Sorting Matrix < 2mm <1 cm 2-5 cm 5-10 cm >10 cm Xenolith Freq. (%) Auto-liths Crus-tal Mantle Alter-ation Vein 257 13.46 2.50 110 0.10 3 2 0 2 15 20 35 20 10 0 75 10 75 15 5 0 258 6.17 2.45 110 0.10 3 2 0 2 10 20 30 25 15 0 85 10 75 15 5 0 259 6.49 2.64 110 0.10 3 2 1 3 15 25 30 30 0 0 80 5 85 10 4 0 260 2.14 2.93 110 0.10 3 1 0 4 20 30 35 15 0 0 65 5 80 15 3 0 Appendix J: Descriptions of the main rock types at Kabanga A total of 137 samples was collected from drillcore and thin sections were produced from each hand specimen. The results of the petrographic analysis are summarized below each rock type. Modal analysis was visual. Ouartzite The sole quartzite sample consists of coarse grains of quartz (96 vol.%) that has undergone deformation (sutured boundaries, sweeping extinction), fine-grained subhedral muscovite (1 vol.%), anhedral pyroxene (1 vol.%), and very fine-grained subhedral pyrite and magnetite (1 vol.% each). Schist The only schist sample is well foliated with plagioclase (7 vol.%) porphyroblasts with leucoxene stippling. It consists of muscovite (25 vol.%) and very fine to coarse-grained quartz (60 vol.%). Opaque minerals (8 vol.%) occur in layers with muscovite and medium grained quartz. They are rounded, elongate grains of magnetite (1 vol.%) at the margins of pyrrhotite and in silicates, and highly irregular pyrrhotite (7 vol.%), with exsolution patches of chalcopyrite. Metapelite The Banded Pelitic Unit is a metasedimentary rock with parallel bedding, varying in thickness from 1mm to ~7 cm, and common foliation in the regions surrounding the Kabanga North body. Light-coloured beds consists of medium-to-coarse grained quartz, with minor muscovite, biotite, feldspar and opaques. Dark-coloured beds are fine-grained and tend to be richer in biotite, zoisite and zeolite. These beds tend to host the majority of square to elongate, up to 3 mm long, parallel oriented porphyroblasts that have been retrogradely altered to coarse grained quartz and opaques, with zeolite, biotite, plagioclase, and chlorite. Opaque minerals occur in low abundances (5-7 vol.%, trace-5 vol.% pyrite, 2-5 vol.% magnetite, trace chalcopyrite) and tend to be disseminated very fine-grained magnetite with hematite alteration, with trace irregularly shaped chalcopyrite and pyrite. Coarser sulfide minerals tend to be medium to fine-grained, feathery pyrite occurring with biotite laths, mantled by chalcopyrite. 142 The Lower Pelitic Unit tends to be foliated, as defined by sulfide mineral-bearing layers and parallel alignment of elongate grains. Local bedding consists of alternating light coloured layers up to 4 cm thick and dark coloured layers from 1 mm to 1 cm thick. The metasediments consist of very fine to medium grained quartz (8-91 vol.%), irregular muscovite (0-20 vol.%), irregular to lath shaped biotite (1-15 vol.%), dumortierite/ sillimanite (0-65 vol.%), plagioclase (0-35 vol.%), amphibole (0-10 vol.%), cordierite (0-10 vol.%) with trace-5 vol.% iron hydroxide staining around the opaques and 2-15 vol.% opaques (trace-9 vol.% pyrr, trace-5 vol.% py, trace-1 vol.% cpy, trace-2.5 vol.% pent, trace-1 vol.% ilm, trace-2 vol.% mag). Pyrrhotite occurs as roundish to elongate, irregular, very fine to coarse grains locally mantled by pyrite and magnetite, with exsolution blebs of chalcopyrite and lesser pentlandite. Pyrite occurs as very fine disseminated grains and filling fractures. Ilmenite occurs as lath-shaped grains with variable degrees of magnetite replacement, within biotite clusters, mantled by chalcopyrite and pyrrhotite. Dark coloured layers tend to be richer in clay/cordierite/sillimanite, amphibole and biotite, with elongate trails of sulfides, whereas the light coloured layers tend to be richer in quartz. Local porphyroblasts have been retrogradely altered to quartz and biotite Metasedimentary rocks are locally cut by veins consisting of coarse quartz, biotite and muscovite, or muscovite, or clay, or sulfides (pyrite and pyrrhotite). Diabase Diabase samples (Table J.l) are typically medium grey and competent. They consist of fine to coarse, anhedral to subhedral plagioclase, with leucoxene stippling indicating saussuritization occurred during greenschist-facies retrograde metamorphism (Evans et al., 2000), local fine grained quartz, phlogopite occurring in patches crystallized around subhedral pyroxene (clino-and orthopyroxene), coarse amphibole laths also resulting from retrograde metamorphism (Evans et al, 2000), and local rutile and spinel, which is occurring in clusters with opaques. Opaque minerals are commonly anhedral to subhedral laths of ilmenite variably altered to magnetite, mantled by silicates and sulfides. There is also very fine-grained magnetite and ilmenite replacing the ferromagnesian minerals and lesser disseminated, very fine, irregular sulfides (chalcopyrite and pyrite). Sulfides, when in high abundance, occur as net-textured, interstitial phase predominantly consisting of pyrrhotite with exsolution blebs of chalcopyrite and pentlandite. Spinel occurs in samples with abundant sulfides as an interstitial phase associated with phlogopite. 143 Samples from the North body differ from those of the Main body by having generally more amphibole, chlorite, leucoxene and quartz while having fewer sulfides and oxides, pyroxene, and plagioclase. The samples are also locally foliated, nearest to the ultramafic and massive sulfide sections of the body. The North body appears to be more pervasively altered than the Main body, thus replacing the ferromagnesian minerals with amphibole, which is subsequently altered to chlorite. Furthermore, the North body may originally have had lower sulfide contents or sulfides have been remobilized out of the body during metamorphism. Drillhole Depth 128.5 KN03-33 152.4 161.9 165.35 KN97-08B 612 166.55 209.3 KN98-56 225.65 309.95 506.6 461.4 Body North North North North North Main Main Main Main Main Main Foliation No No No Yes Yes No No No No No No Amphibole 75 50 70 0 4 0 50 32 2 30 87 Chlorite 0 0 3 3 0 0 0 0 0 0 0 Clinopyroxene 0 0 0 0 0 25 0 0 3 0 0 Leucoxene 3 5 0 0 0 0 3 t t 0 0 Orthopyroxene 0 0 0 0 0 0 0 0 65 0 0 Phlogopite 0 t 0 0 75 0 0 0 5 0 1 Plagioclase 0 30 5 10 15 35 40 22 15 60 5 Quartz 15 7 7 50 0 t 4 5 0 8 5 Pyrite 3 0 t 0 0 t 0 0 t 1 t Pyrrhotite 0 t t 3 0 0 t 37 7 0 t Pentlandite 0 0 0 2 0 0 t 1 1 0 t Chalcopyrite 0 t t 25 0 t t 2 1 0 t Magnetite 4 2 5 0 0 6 0 0 t 2 1 Ilmenite 0 t t 0 0 2 3 0 0 t 1 Spinel 0 0 0 t 0 0 0 0 1 0 0 Rutile 0 1 0 0 0 7 0 0 0 0 0 Table J . l : Table detailing the modal percent estimates of silicate and opaque mineralogy of the diabase samples from the North and Main bodies at Kabanga, as estimated from optical petrography. T is for trace amounts (less than lvol.%). Gabbro Gabbro samples (Table J.2) consist of medium to coarse (up to 1 cm x 1 mm), subhedral pyroxene (ortho and clinopyroxene), phlogopite, serpentine and locally sulfides. The interstitial material consists of clinopyroxene, plagioclase, sulfides, serpentine, amphibole, and phlogopite. The pyroxenes are typically being altered along rims and fractures to amphibole, which is locally further altered to talc. Plagioclase is locally replaced by talc or chlorite, biotite, and amphibole. The fine-grained net textured sulfides are dominantly pyrrhotite with exsolution blebs of pentlandite and chalcopyrite (locally with bornite "basketweave" textured exsolution). Pyrrhotite and chalcopyrite appear to have been also remobilized into the silicates, occurring along cleavage and as tiny disseminated grains throughout the silicates. Spinel occur as irregular, elongate, coarse grains at the margins of the net textured pyrrhotite, with alteration 144 rims of magnetite. Magnetite occurs as disseminated grains, as alteration of ilmenite lenses within phlogopite, mantling pyrrhotite, and filling fractures in pentlandite. Samples from the North body differ from those of the Main body in that they typically have a weak foliation defined by parallel alignment of elongate minerals. The North body gabbro typically has more amphibole, while having less pyroxene, suggesting that they are more altered, less plagioclase, suggesting that they are potentially more mafic and less evolved, and less sulfides. These characteristics are consistent with those observed in the diabase samples. Drillhole Depth 293.4 KN03-33 309.4 305.8 374.05 380.05 KN98-56 392.03 407 511.3 538.3 KN05-07 351.2 Body North North North Main Main Main Main Main Main Main Foliation No Yes Yes No No No No No No No Amphibole 0 60 56 15 30 5 45 40 40 20 Chlorite 25 0 0 0 3 0 0 0 0 0 Clinopyroxene 0 0 10 5 1 5 5 0 5 0 Orthopyroxene 0 0 0 32 20 25 10 5 10 0 Phlogopite 35 5 15 0 1 5 5 27 2 15 Plagioclase 25 15 15 33 0 20 25 25 30 43 Serpentine 0 . 0 0 0 5 0 0 0 0 5 Talc 0 9 0 0 0 0 0 0 5 15 Pyrrhotite 5 t 2 13 34 36 7 2 1 t Pentlandite 1 0 t 1 2 3 1 t t 0 Chalcopyrite 2 t t t 2 t 1 t 0 t Pyrite 1 0 0 t t t t 0 0 0 Magnetite 1 0 0 t 1 t 1 t 1 2 Ilmenite 0 0 0 0 0 0 t 1 1 t Spinel 0 0 0 1 1 1 0 0 0 0 Rutile 0 1 2 0 0 0 0 0 0 1 Table J.2: Summary of the modal percent estimates of mineralogy for the gabbro samples from the Kabanga North and Main ore bodies, t is for trace amounts (less than 1 vol.%). Pyroxenite Pyroxenite samples (Table J.3, Table J.4) consist of fine to medium grained olivine cumulus grains being replaced by serpentine and magnetite with lesser sulfides, fine grained clinopyroxene cumulate grains and coarse poikilitic orthopyroxene. Pyroxene is altered to amphibole, with serpentine along rims and fractures. Interstitial phases include pyroxene (both clino- and orthopyroxene), phlogopite and local plagioclase. Sulfide minerals hosted within pyroxenite are disseminated to net-texutred pyrrhotite occurring as an interstitial phase. Pentlandite and chalcopyrite occur as exsolution phases within the pyrrhotite, and pentlandite appears to be more abundant relative to pyrrhotite than in peridotite. Magnetite occurs mantling the interstitial sulfides and as very fine grains replacing the silicate minerals. Ilmenite occurs as lenses within phlogopite, and is locally being replaced 145 by magnetite. Magnetite and ilmenite appear to be more abundant in the pyroxenite than peridotite samples, indicating more pervasive alteration of ferromagnesian minerals and crystallization from a more evolved magma, respectively. Spinel, as a cumulus phase typically occurring with the sulfides, is less abundant in the pyroxenite than peridotite samples. Chalcoeite is present in the pyroxenites of the North body, and is absent in those from the Main body. Samples from the North body are locally foliated, while those of the Main body are not. The North body pyroxenites are also more pervasively serpentinized (far less olivine preserved) and host fewer sulfides than those from the Main body. Drillhole D e p ? h (m) Textures c >, .2 o to Veins C D 3 Cumulus Textures Grain Size > a> c 0) a >i a. o c Interstitial Material >> a a-I 1 o o ta m © :)£ £ B) in 0 c o = 01 <» o 2* ° S- o> S. JC a » o o. co a. a o ja a. E < Alteration 8 S • a s i g- i a | s- ° = I a a) -<= o -3 o CO Q . — ^ KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 231.2 233.4 241.2 251.6 257.8 265.5 269.4 272.1 282.7 289.05 299.4 237.55 254.8 299.35 309 337 339.45 432.3 serp, op mag serp py, chl N op, serp N N serp, op N N N N N py mag, serp N N N carb N N Y N fine fine-coarse med-coarse fine-med fine-coarse N fine-coarse N fine-coarse fine-coarse fine-med med-coarse N fine N med-coarse N fine fine- coarse fine-coarse fine-coarse fine-coarse fine-coarse N N N N Y Y N Y Y Y Y Y N N N N N N Y Y Y Y Y Y Y Y Y Y Y Y Y Y N Y Y Y N Y N N N N N Y N N N N N N N N N N N N N N N N N N Y Y N N Table J.3: Summary of the main textures of the pyroxenite samples from the Kabanga North (N) and Main (M) bodies. Cumulus textures described the size and minerals occurring as cumulus grains. Interstitial material describes the minerals filling the space between cumulus grains. Alteration describes which phases are occurring as alteration phases of either the cumulus grains or interstitial material. Pseudomorphed indicates if any cumulus grains have been completely pseudomorphed, opaques are opaque minerals (including both oxides and sulfides). 146 Drillhole Depth (m) Silicate Modal Mineralogy o> a a I '5. ™ Q. O -g E c ra < a o 0) 41 c c a) o) x >< S S >• 2> a. a I i o o o c c 0) a. u 0) (0 a> a u «> ra • C o " O O CO J= '5> O ra Q . Sulfide Modal Mineralogy <D 2 £ S V >> Js a> £ ra O E fc fc S o o ^ Q . i> J : S e c ra CO £ s -5 ° o © KN03-33 231.2 3 5 5 3 2 0 66 1 0 0 3 4 t 0 t 8 t 0 0 t KN03-33 233.4 15 5 0 5 5 0 65 0 0 0 1 1 t 0 t 3 t 0 0 0 KN03-33 241.2 12 1 0 3 5 0 65 0 1 0 . 4 2 t. t t 5 0 0 0 KN03-33 251.6 15 2 0 2 1 0 65 1 0 3 2 t t t 7 1 0 0 t KN03-33 257.8 10 4 0 6 5 t 68 0 0 0 t 1 t 0 0 4 0 0 t KN03-33 265.5 10 5 0 5 5 0 70 0 0 0 t 1 t 0 0 2 1 1 0 t KN03-33 269.4 5 3 0 9 13 0 65 5 0 3 t t t t 0 3 1 0 0 t KN03-33 272.1 25 0 0 0 0 0 65 0 0 0 t 1 t 0 0 8 t 1 0 t KN03-33 282.7 40 0 0 20 5 0 25 0 0 5 2 2 t 0 0 6 t t 0 t KN03-33 289.05 60 10 0 3 2 0 18 0 0 0 2 2 t 0 0 1 1 1 0 0 KN03-33 299.4 30 5 0 10 0 0 35 0 0 0 3 1 t 0 0 4 t 2 0 0 KN98-56 237.55 5 5 26 7 t 0 35 5 0 0 4 t t 0 0 2 1 t 0 0 KN98-56 254.8 50 5 0 0 0 0 32 0 0 0 5 3 t 0 2 t t 2 0 0 KN98-56 299.35 3 7 0 2 55 7 6 2 10 0 6 t t 0 0 1 t t 0 0 KN98-56 309 0 1 0 3 40 7 10 2 0 0 12 2 2 t t 2 2 0 0 0 KN98-56 337 20 1 0 0 20 10 24 5 0 0 12 2 2 0 t 2 2 t 0 0 KN98-56 339.45 4 1 0 3 50 7 5 2 3 0 17 3 2 t t 1 2 0 0 0 KN98-56 432.3 40 3 2 0 12 10 30 0 0 0 1 t t 0 t 1 1 t 0 0 Table J.4: Summary of the modal mineralogy of the pyroxenite samples from the Kabanga North (N) and Main (M) bodies. T is for trace amounts (less than lvol.%). Peridotite Peridotite samples (Table J.5, Table J.6) generally exhibit a cumulus texture with typically three generations of cumulus grains, starting with fine to medium grained, subhedral to euhedral olivine, then fine grained clinopyroxene (CPX) which also forms as an interstitial phase to the olivine cumulates, then coarse grained orthopyroxene (OPX) poikilitically including CPX cumulus grains. Many samples lack CPX and OPX cumulates, and pyroxene occurs solely as an interstitial phase. The spatial distribution of these samples containing and lacking pyroxene cumulates suggests the presence of several flows. Olivine cumulates have then been completely pseudomorphed by serpentine, with opaques along fractures and as coarse grains within the cores of grains, with lesser amounts of amphibole. Pyroxene is typically altered along rims and fractures to very fine-grained amphibole (uralite) and cut by serpentine and opaque veinlets. 147 Late interstitial phases include phlogopite, with boxwork oxides, disseminated to net textured sulfides, and patches of serpentine and lesser amphibole as an alteration phase. Peridotite samples are locally foliated, as defined by elongation of cumulus grains and parallel alignment of serpentinized veinlets. Interstitial sulfides are predominantly pyrrhotite with exsolution blebs of pentlandite, which are highly fractured and infilled with magnetite, and chalcopyrite, locally with basketweave textured exsolution of bornite. Chalcocite is associated with chalcopyrite or pentlandite. Sulfide minerals also occur as angular grains intergrown with the alteration silicates (amphibole and serpentine) and as very fine grains pseudomorphing and in the fractures silicates, suggesting that they have been remobilized during the alteration of the silicates. Pyrite occurs locally as very fine grains within the pseudomorphed silicates, filling veinlets, and as very fine exsolved grains in pyrrhotite. Magnetite occurs as very fine grains pseudomorphing ferromagnesian minerals, in fractures of pseudomorphed silicate minerals, in veinlets with serpentine, and mantling the interstitial sulfide minerals, suggesting that it is a late phase associated with serpentinization. Ilmenite occurs as laths within the cleavage of phlogopite and as subhedral elongate grains, locally being altered to magnetite. Subhedral to euhedral spinel cumulus grains are common, occurring in clusters within OPX and mantling the interstitial sulfides, also with thick alteration rims of magnetite. Peridotite of the Kabanga Main body differs from that from the North body in that there are remnant olivine cores within the cumulus grains, suggesting that serpentinization has been less pervasive, and the olivine cumulates are instead being altered to a variety of minerals (biotite, chlorite, iddingsite, carbonate). Also, plagioclase occurs as an interstitial phase, whereas in the Kabanga North peridotites it was either non-existent or completely replaced. Sulfides, on average, occur in higher abundances, though there appears to be less magnetite, likely due to the lesser degree of serpentinization. However, the Kabanga Main peridotites appear to lack chalcocite. 148 Drillhole Depth >. .2 o .2 Cumulus Minerals a c 0) X s >» a. o c o X O •a o o c -c o a o H £ » O 0. Interstitial Minerals c <D X s > a o _c O CD c o 2 & "§• g 1 2 8 .E co c o 3. ET 21 « a! i S Q . CO Q. O KN03-33 211.45 N N N N Y Y Y N Y Y N Y Y N Y Y N N N Y KN03-33 212.9 N N N Y Y Y Y Y Y Y N Y N N Y Y N N N Y KN03-33 218.2 N N N Y Y Y Y Y Y Y N Y N N Y Y. N N N Y KN03-33 224.45 N N N Y Y Y Y Y Y N N Y N N Y Y N N N Y KN03-33 240.5 N Y N Y Y Y Y Y Y Y N Y N N Y Y Y N N Y KN03-33 246.9 N Y N N Y Y Y Y Y Y N Y N N Y Y N N N Y KN03-33 249.05 N Y N N N Y Y Y Y Y N Y N N Y Y N N N Y KN03-33 250.9 N N N N N Y Y N Y Y N Y N N Y Y N N N Y KN03-33 263.05 N N N Y Y Y Y Y Y Y N Y N N Y Y N N N Y KN05-03 177.3 M Y Y N Y N Y Y Y Y Y Y N N Y Y N Y N Y KN05-05 165 M Y N Y Y Y N N Y N Y Y N Y Y Y Y N Y Y KN05-30 270.2 M Y Y N Y N N N N N Y Y N N Y Y N N Y Y KN98-56 208.7 M N N Y Y Y Y Y Y Y N Y N N Y Y N N . N Y KN98-56 262.8 M N Y Y Y Y Y Y Y Y N Y N N Y Y N Y N Y KN98-56 271.3 M Y Y N Y N Y Y Y Y Y Y N N Y Y N N N Y KN98-56 289.4 M N Y Y N N Y Y Y Y Y Y N N Y Y N Y N Y KN98-56 292.95 M Y Y Y N N Y Y Y Y Y Y N N N Y N N N Y KN98-56 296.05 M Y Y Y N N N Y Y Y Y Y N N N Y Y Y N Y KN98-56 313.45 M Y N N N Y N N Y Y N Y N N Y Y N Y N Y KN98-56 321.7 M Y Y N N N N Y Y Y N Y N N Y Y N Y N Y KN98-56 343.05 M Y Y N Y N Y Y Y Y Y Y N N Y Y N Y Y Y KN98-56 346.8 M Y Y N N N N Y N Y N Y N N Y Y N Y Y Y KN98-56 351.45 M Y Y N N N Y Y Y Y Y Y N N N Y N Y N Y KN98-56 352.05 M Y Y N Y N Y N Y N Y Y N N Y Y N N N Y KN98-56 371.8 M Y Y Y Y N N Y Y Y N Y N N Y Y N Y Y Y KN98-56 417.6 M N Y Y N N Y Y Y Y N Y N N Y Y N N N Y KN98-56 485.56 M Y N Y N Y N N Y Y N Y N Y Y Y N N N Y KN98-56 495.65 M N N Y Y Y N N Y N N N N N Y Y N N N Y KN98-56 541.6 M Y Y Y Y Y N N Y Y Y Y N N Y Y N N Y Y Alteration Minerals c o XI (0 u o to a. 0) CO 0} 1 2 2 ° x: x o. o 2 0) c .2 E to « c fj — CO 2 °-2 O Table J.5: Summary of the main textures of the peridotite samples from the Kabanga North and Main bodies. Interstitial material describes the minerals filling the space between cumulus grains. Alteration describes which phases are occurring as alteration phases of either the cumulus grains or interstitial material. Y is for yes and N is for no. 149 Drillhole Depth Silicate Modal Mineralogy 0) CU <D .ti *< 2 5. ra £ o = a o £ E £ « < £ o c 2 a. o :i * O O & 1 2 O •= <= fe o — a a> CO o "5i ra Q . Sulfide Modal Mineralogy & 2 0 C x ro 1 I o I I S | S 8 8 m o KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN03-33 KN05-03 KN05-05 KN05-30 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 KN98-56 211.45 212.9 218.2 224.45 240.5 246.9 249.05 250.9 263.05 177.3 165 270.2 208.7 262.8 271.3 289.4 292.95 296.05 313.45 321.7 343.05 346.8 351.45 352.05 371.8 417.6 485.56 495.65 541.6 23 20 10 13 10 10 11 27 10 3 5 4 17 7 2 2 0 0 1 1 2 1 0 1 1 10 40 2 7 7 7 2 7 1 2 5 5 . 10 0 5 5 8 7 5 1 3 2 2 1 5 1 1 5 1 45 10 2 3 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 t 20 0 0 3 5 5 3 5 5 1 1 10 5 2 0 3 5 5 2 7 8 7 3 5 1 0 5 25 40 55 15 20 30 40 56 55 60 65 60 70 0 60 0 60 30 30 0 2 2 50 50 32 13 15 13 20 15 35 15 35 34 0 2 30 41 27 40 25 30 0 5 50 34 70 65 33 15 25 15 32 8 25 10 35 0 23 25 7 0 0 0 0 0 0 0 0 0 2 35 27 0 0 4 1 5 1 0 0 3 0 2 20 0 0 0 0 20 10 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 t 60 0 9 1 1 1 3 t 4 t t 6 1 7 5 2 4 6 3 10 14 16 9 9 5 11 11 2 5 5 4 10 3 8 6 4 10 6 6 8 1 0 1 4 4 2 3 2 3 4 3 2 2 2 1 2 2 5 3 1 0 t t t 2 2 1 2 1 t t t 0 t 3 1 1 2 3 1 t 2 3 2 10 t t 1 t Table J.6: Modal mineralogy estimates for peridotite samples from Kabanga Main and North. T is for trace amounts (< lvol.%). Semi-Massive Sulfide Semi massive sulfide samples (Table J.7, Table J.8), as defined by those with more than 30vol.% opaques, from the North ore body are all peridotitic in origin. By contrast, the semi massive sulfide samples from the Main body are both peridotites and pyroxenites. Semi massive sulfide samples typically have the same cumulate textures observed in the peridotites and pyroxenites, but with a higher abundance of opaques (>30vol.% opaques) as an interstitial phase and also as replacement of the ferromagnesian silicates, associated with serpentinization. Olivine, orthopyroxene and clinopyroxene occur as cumulus grains, though 150 olivine is typically pseudomorphed by serpentine, with opaques along fractures and pyroxene is altered to serpentine and opaques to varying degrees, as well as amphibole, chlorite, and phlogopite. The interstitial phases are predominantly opaques with lesser serpentine, fibrous amphibole, phlogopite, and OPX, as an interstitial phase to CPX. Sulfides of the semi massive sulfide samples are predominantly net textured pyrrhotite with exsolution blebs of highly fractured pentlandite and chalcopyrite, with local basketweave exsolution of bornite, all typically occurring as angular intergrowths with serpentine and amphibole at their margins. The sulfides also occur as very fine grains on and in the fractures of altered silicate minerals. Magnetite occurs mantling the interstitial sulfides, as very fine grains and filling fractures in silicates. Spinel occurs as fine to medium sized, subhedral, poikilitic grains with magnetite alteration around the rims. Ilmenite locally occurs in the Kabanga Main body as highly irregular grains intergrown with phlogopite, mantling sulfides and being mantled by magnetite. Semi massive sulfide samples of the North body tend to be pervasively altered to serpentine and amphibole, with more magnetite, whereas relict pyroxene and olivine commonly occur in the semi massive sulfide samples from the Main body. The Kabanga Main semi massive sulfide samples tend to be more spinel and sulfide rich though with relatively less pentlandite. The samples from the KN98-56 drillhole from the Main body are less altered than those of the North body but more altered than the remaining samples from the Main body, with alteration increasing with depth in the hole. 151 Drillhole Depth Body Foliation Veins Grain Size Cumulates Interstitial minerals Texture Alteration minerals KN03-33 181.4 N N Y fine pseudo. sulf, amph 3 chl, phlog, serp, amph KN03-33 183.8 N Y Y fine pseudo. sulf, serp, amph 4 serp, op, phlog, amph KN03-33 185.45 N N Y fine pseudo. serp, op, amph, phlog 3 op, serp KN03-33 188.9 N Y Y fine pseudo. serp, amph, sulfides 4 op, serp KN03-33 196.85 N N N fine pseudo. serp 4 op, serp KN03-33 206.25 N Y N fine pseudo. serp 4 serp, op, amph , KN03-33 206.8 N N N fine-med. pseudo. serp, phlog, op 4 op, serp KN03-33 208.2 N N Y fine pseudo. sulf, phlog 3 serp KN05-02 771.9 N N N medium pseudo. sulf, chl, amph 1 amph, chl, op, serp KN05-23 245.8 M N N medium cpx, opx, plag plag, phlog, sulf 2 amph, chl KN05-26 237.85 M N N fine-med. opx, ol op, phlog serp, plag 1 amph, serp, op, biotite KN05-26 249.31 M N N fine plag, phlog sulf 1 serp KN05-30 126.8 M N N fine pseudo. sulf 3 carb, serp, phlog, amph KN05-33 381.5 N N N fine-med. pseudo. serp, op 4 serp, op, amph KN97-08B 592 N N Y medium opx, cpx sulf, serp 3 op, serp, amph, op KN97-08B 595 N Y N fine opx, pseudo. sulfides 4 serpentine, amph KN98-56 297.8 M N N fine opx, cpx sulf, phlog, plag 0 serp, phlog KN98-56 317.35 M N Y fine opx, op, serp, spinel, opx 0 serp, op KN98-56 325.45 M N N med-coarse opx, cpx sulf, plag, serp, op, phlog 0 serp, op, phlog Table J.7: Summary of some main textural characteristics of the semi massive sulfide samples from the Kabanga North (N) and Main (M) samples, including grain size (fine, medium, coarse) and mineral comprising the cumulus grains, the nature of the interstitial phases and the minerals occurring as alteration of either the cumulate grains or the interstitial phases. Texture refers to the degree of texturally destructive alteration (0 for preserved, 1 for mostly preserved, 2 for partially preserved, 3 for partially destroyed, and 4 for destroyed). Y is yes, N is no. Mineral abbreviations are as follows: cpx = clinopyroxene, opx = orthopyroxene, plag = plagioclase, sulf = sulfides, amph = amphibole, op = opaque minerals, serp = serpentine, phlog = phlogopite, chl = chlorite, pseudo = pseudomorphed. 152 Drillhole Depth KN05-23 245.8 15 1 3 15 0 0 1' 15 44 3 1 t 0 2 t KN05-26 237.85 1 7 0 25 1 8 7 18 25 3 2 0 t t t KN05-26 249.31 0 7 0 0 0 t t 10 60 3 1 0 0 0 5 KN05-30 126.8 7 1 0 0 0 7 0 0 35 1 1 0 t 10 1 KN98-56 297.8 0 t 15 15 0 10 0 5 25 5 t t t 3 2 KN98-56 317.35 0 0 0 5 0 55 0 0 27 3 t 0 3 5 2 KN98-56 325.45 1 4 1 3 0 50 1 5 29 2 t 0 0 2 2 KN03-33 181.4 10 7 0 0 0 10 25 0 25 3 1 t 0 t 6 KN03-33 183.8 25 5 0 0 0 25 0 0 15 5 5 0 2 8 2 KN03-33 185.45 5 5 0 0 0 55 0 0 15 8 3 0 t 9 1 KN03-33 188.9 8 2 0 0 0 55 0 0 10 5 1 0 1 18 0 KN03-33 196.85 0 0 0 0 0 49 0 0 23 5 1 0 1 20 0 KN03-33 , 206.25 0 3 0 0 0 45 0 0 27 5 2 0 15 0 KN03-33 206.8 0 0 0 0 0 44 0 0 35 5 1 0 1 13 0 KN03-33 208.2 15 3 0 0 0 40 0 0 10 10 t t. t 20 2 KN05-02 771.9 35 0 0 0 0 10 15 0 20 4 1 0 t 5 t KN05-33 381.5 1 0 0 0 0 56 0 1 35 2 3 0 t 0 KN97-08B 592 25 0 10 15 0 20 0 0 7 1 1 t 1 9 0 KN97-08B 595 42 0 0 3 0 10 0 0 42 1 1 0 t 1 0 Table J.8: Table summarizing model mineralogy estimates for semi-massive sulfide samples from Kabanga Main and North ore bodies. T is for trace amounts (<1%). Massive Sulfide Massive sulfide (Table J.9) predominantly consists of pyrrhotite with exsolution blebs of pentlandite, anhedral chalcopyrite (locally with "basketweave" textured exsolution of bornite), and anhedral to subhedral pyrite. Samples locally have chalcocite, typically occurring spatially associated with chalcopyrite, arsenopyrite (in the samples from the Kabanga Main body), or very fine irregular grains of cobaltite (in the samples from the Kabanga North body). Spinel occurs as anhedral to euhedral grains mantled by and hosting poikilitic inclusions of sulfides and being replaced around the rims by magnetite, to varying degrees. Magnetite also occurs filling fractures in pyrrhotite and pentlandite. Massive sulfide samples typically host inclusions of silicates consisting of serpentine, phlogopite, pyroxene, amphibole, with pyrrhotite and spinel. There are also commonly veins filled with numerous layers of colloform serpentine, hematite and magnetite, with pyrite veins occurring in the samples of the Main body. 153 KN03-33 178.8 North 0 1 67 30 1 t 0 t 2 0 KN03-33 179.2 North 0 1 90 7 1 t 0 t 1 t KN05-03 294.3 Main 1 0 84 5 3 t 0 0 2 1 KN05-12 390.1 1 1 94 2 1 t 0 0 2 1 KN05-26 242.8 Main 0 1 87 6 1 5 t 0 1 t KN05-26 254.2 Main 1 1 85 3 1 10 t 0 1 t KN05-30 298.6 Main 0 1 92 3 1 1 t 2 1 t KN05-33 369 North 0 0 80 14 1 t 0 1 2 KN05-33 401 North 1 1 96 2 2 t 0 0 t t KN98-56 295.05 Main 0 1 91 3 1 2 t 1 2 1 KN98-56 312.03 Main 1 1 89 8 1 t t 1 1 1 Table J.9: Summary of the modal mineralogy (as a percent, t for trace amounts) for the massive sulfide samples gathered from both the Kabanga Main and North bodies. T is for trace amounts (< 1%). 154 Appendix K: Physical property histograms Figure K . 1: Physical property histograms for the various rock types at Kabanga constructed using measurements from a database assembled by Barrick Corp ("the database), with magnetic susceptibility (left column) and density (right column). Diabase Log(Susceptibility) [log(10"3 SI)] Density (g/cc) 155 Peridotite Log(Magnetic Susceptibility) [log(10"3SI)] Density (g/cc) Table K . l : Physical property statistics of the mafic-ultramafic and mineralized rock types at Kabanga calculated from the database assembled by Barrick Corp ("the database"). Rock Type Susceptibility (103 ST) Density (g/cm3) Diabase 1.67 ±4.00 3.099 ±0.508 Gabbro 14.44 ±2.66 3.069 ±0.296 Pyroxenite 8.38 ±2.80 3.040 ±0.254 Peridotite 12.43 ±2.72 3.001 ±0.244 Semi-massive Sulfide 6.24 ±10.12 3.166 ±0.456 Massive Sulfide 6.20 ±3.91 4.279 ±0.493 156 Appendix L: Physical Property and Geochemical Data for the Kabanga Samples Geochemical analyses were performed by A L S Chemex in Vancouver, B.C. Whole rock analyses displayed here were obtained using the X R F method (Table L . l ) . Values are percentages, valid from 0.01-100%. Trace elements (columns 4-16 of Table L.2) were obtained using ICP-MS and ICP-AES techniques on acid regia leaches of each sample. Precious metals (Au, Pt, and Pd) were analysed by fire assay and ICP-AES finish (Table L.2). Concentrations of the precious metals are valid between 0.005-10 ppm for Pt and 0.001-10 ppm for Au and Pd. H20 + was quantified using the Leco method, as was C, and values are valid between 0.01-100% (Table L.3). H2O" was quantified using a gravimetric procedure after drying at 105°C, and also ranges from 0.01-100%. FeO was quantified using HC1-HF acid digestion and titrimetric finish, with values ranging from 0.01-100 %. CO2 (inorganic carbon) was obtained by HC1 leach and Leco-gasometric finish (Table L.3). Values are valid from 0.2-50%. Physical properties were obtained using the techniques outlined in Appendix E. Table L . l : Physical Properties and Major Element Geochemistry for Kabanga Samples Sample Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) Si02 Al203 Fe203 CaO MgO Na20 K20 Cr203 Ti02 MnO P205 LOI Total Averaae s t a n d a r d r g  D e v j a t i o n % % % % % % % % % % % % % K1B-06 395.26 Sedimentary 13.7 2.860 63.66 16.02 8.28 0.19 1.52 0.53 3.68 0.01 0.69 0.02 0.07 5.15 99.89 KN03-33 128.5 Diabase 0.5 0.0 2.802 50.99 13.05 10.42 3.47 13.45 0.13 0.06 0.22 0.66 0.24 0.07 6.86 99.63 KN03-33 150.8 Sedimentary 0.6 2.820 69.38 11.18 11.31 0.40 0.93 0.26 1.55 0.01 0.42 0.06 0.23 3.97 99.73 KN03-33 152.4 Diabase 29.4 4.600 0.38 0 86.50 0.04 0 0 0 0.11 0 0.01 0.05 12.90 100 KN03-33 161.9 Diabase 0.6 0.0 2.784 52.83 13.45 11.23 2.13 11.94 1.14 0.11 0.14 0.7 0.19 0.06 5.86 99.78 KN03-33 165.35A Diabase 0.4 0.0 3.051 32.00 3.68 18.01 1.03 32.46 0.15 0.17 0.63 0.16 0.12 0.03 11.00 99.43 KN03-33 165.35B Diabase 0.4 3.051 54.38 13.89 14.64 3.58 2.15 0.31 0.62 0.01 0.76 0.08 0.29 7.41 98.15 KN03-33 168.2 Sedimentary 0.3 2.720 70.51. 15.61 5.30 0.27 1.12 0.43 3.02 0.01 0.59 0.04 0.10 2.86 99.93 KN03-33 177.4 Sedimentary 0.3 0.0 2.821 55.04 15.71 14.81 0.13 4.65 0.26 2.40 0.03 0.67 0.10 0.06 5.89 99.82 KN03-33 178.0 Massive Sulfide 0.6 2.800 52.85 14.21 10.17 4.95 11.46 0.54 0.06 0.14 0.55 0.11 0.04 4.62 99.72 KN03-33 179.2 Massive Sulfide 31.7 3.8 4.671 1.30 0.51 78.5 0.05 0.24 0.01 0.07 0.47 0.04 0.03 0.04 12.05 93.30 KN03-33 181.4 Semi Massive Sulfide 46.0 3.100 26.47 4.33 37.94 2.51 18.01 0.21 0.19 1.75 0.25 0.49 0.03 7.91 100.1 KN03-33 183.8 Semi Massive Sulfide 27.4 2.980 34.24 4.24 20.84 2.46 26.42 0.18 0.22 1.24 0.19 0.49 0.04 9.44 99.99 KN03-33 196.85 Semi Massive Sulfide 612.6 51.8 3.311 24.00 1.55 41.32 0.03 21.73 0.12 0.08 0.05 0.06 0.08 0.01 10.65 99.67 KN03-33 206.25 Semi Massive Sulfide 346.6 30.9 3.193 23.46 1.27 41.86 0.05 23.02 0.10 0.03 0.01 0.08 0.05 0.04 9.95 99.93 KN03-33 206.8 Semi Massive Sulfide 542.7 3.350 20.13 .0.63 49.09 0.02 19.11 0.05 0.07 0.01 0.13 0.05 0.02 10.45 99.77 KN03-33 208.2 Semi Massive Sulfide 125.0 2.870 30.92 2.05 28.94 0.21 27.15 0.19 0.15 0.08 0.24 0.16 0.01 9.59 99.69 KN03-33 211.45 Peridotite 90.4 16.7 2.841 34.88 4.00 18.16 1.29 29.98 0.21 0.30 0.14 0.22 0.10 0.01 10.40 99.70 KN03-33 212.9 Peridotite 87.1 5.0 2.812 37.72 4.35 12.94 2.28 31.75 0.18 0.46 0.18 0.26 0.13 0.03 9.60 99.89 KN03-33 224.45 Peridotite 104.8 2.790 40.72 4.33 8.48 2.71 32.59 0.16 0.44 0.19 0.22 0.14 0.03 9.89 99.90 KN03-33 233.4 Pyroxenite 84.2 3.5 2.980 37.62 3.96 11.87 1.94 32.93 0.19 0.43 0.18 0.20 0.09 0.03 10.40 99.84 —1 Sample Rock Type Magnetic Susceptibility (1<T SI) Density (g/cm3) Si02 AI203 Fe203 CaO MgO Na20 K20 Cr203 Ti02 MnO P205 LOI Total Average Standard Deviation % % % % % % % % % % % % % KN03-33 240.5 Peridotite 141.0 18.6 2.858 KN03-33 246.9 Peridotite 175.4 2.800 38.08 4.27 10.65 2.53 33.16 0.21 0.34 0.46 0.21 0.14 0.02 9.81 99.89 KN03-33 249.05 Peridotite 251.8 51.6 2.872 33.13 3.9 18.59 0.99 31.45 0.22 0.18 0.36 0.15 0.12 0.02 10.70 99.8 KN03-33 250.9 Peridotite 135.0 12.6 2.797 36.57 4.34 12.44 1.60 32.97 0.23 0.27 0.45 0.18 0.13 0.03 10.60 99.81 KN03-33 251.6 Pyroxenite 326.0 2.860 34.97 3.94 15.05 1.69 32.84 0.30 0.17 0.41 0.16 0.12 0.02 10.35 100 KN03-33 263.05 Peridotite 102.4 2.810 37.61 3.74 10.43 2.16 35.05 0.26 0.25 0.50 0.17 0.16 0.03 9.60 99.96 KN03-33 265.5 Pyroxenite 37.5 5.4 3.106 45.07 4.85 8.99 6.27 23.48 0.17 0.04 0.36 0.22 0.15 0.01 10.10 99.72 KN03-33 269.4 Pyroxenite 99.0 2.830 37.49 3.60 10.75 1.90 36.10 0.26 0.24 0.55 0.16 0.16 0.02 8.76 100 KN03-33 289.05 Pyroxenite 0.7 0.2 3.270 39.8 3.84 12.08 1.53 35.71 0.16 0.12 0.43 0.24 0.12 0.03 5.80 99.88 KN03-33 299.4 Pyroxenite 88.5 2.830 41.22 5.44 10.61 3.42 29.80 0.17 0.04 0.57 0.27 0.15 0.04 8.22 99.93 KN03-33 305.8 Gabbro 2.3 0.3 2.938 48.39 9.67 10.58 5.48 18.33 0.84 1.76 0.27 0.45 0.15 0.03 3.78 99.75 KN03-33 309.4 Gabbro 0.6 2.900 49.95 10.67 9.83 7.01 16.15 1.00 0.78 0.26 0.5 0.16 0.04 3.61 99.98 KN03-33 323.35 Sedimentary 4.6 0.7 2.880 65.74 16.84 5.55 1.27 1.67 1.21 2.89 0.02 0.72 0.04 0.12 3.64 99.78 KN03-33 401 Massive Sulfide 45.2 3.0 4.553 1.50 0.22 83.10 0.06 0.10 0.05 0.02 0.16 0.01 0.03 0.01 13.15 98.40 KN05-02 767.7 Massive Sulfide 43.6 7.0 4.598 0.61 . 0.18 78.50 0.03 0.02 0.02 0.00 0.08 0.01 0.01 0.08 11.4 90.90 KN05-02 771.9 Semi Massive Sulfide 143.4 4.3 3.648 21.20 2.00 61.20 0.30 8.34 0.04 0.03 0.32 0.08 0.19 0.06 5.53 99.30 KN05-03 177.3 Peridotite 56.6 2.5 2.858 35.52 4.98 19.21 2.62 27.64 0.54 0.41 0.18 0.22 0.13 0.04 8.18 99.65 KN05-03 294.3 Massive Sulfide 20.1 2.2 4.585 0.82 0.20 76.50 0.03 0.29 0.02 0.01 0.13 0.02 0.02 0.04 12.55 90.60 KN05-05 165 Peridotite 3.3 0.4 3.033 50.13 6.96 14.30 2.83 20.38 0.63 0.81 0.36 0.41 0.13 0.03 2.87 99.87 KN05-07 351.2 Gabbro 0.5 0.1 2.690 53.52 10.74 8.83 5.06 15.74 0.99 1.34 0.27 0.58 0.12 0.04 2.61 99.88 KN05-07 387.3 Sedimentary 5.8 0.9 2.837 61.31 17.36 7.57 1.20 3.85 0.67 2.98 0.07 0.85 0.04 0.06 3.28 99.29 KN05-11 390 Sedimentary 2.4 0.8 2.846 78.57 5.23 8.72 1.63 2.91 0.20 0.29 0.07 0.29 0.06 0.02 1.84 99.84 KN05-12 390.1 Massive Sulfide 166.0 79.8 4.528 1.96 0.37 80.40 0.06 0.50 0.06 0.16 0.20 0.04 0.01 0.08 13.95 97.80 KN05-21 393.4A Quartzite 14.4 5.9 2.655 97.98 0.29 1.03 0.03 0.07 0.13 0.06 0.07 0.03 0.00 0.01 0.10 99.81 KN05-21 393.4B Schist 0.0 0.0 2.655 65.78 13.23 11.70 0.17 0.75 0.35 2.10 0.02 0.51 0.01 0.04 4.87 99.57 KN05-23 245.8 Semi Massive Sulfide 19.2 2.2 3.813 21.00 1.51 59.40 2.22 6.25 0.36 0.18 0.18 0.11 0.11 0.07 8.40 99.80 KN05-26 237.85 Semi Massive Sulfide 1.0 0.0 3.603 29.30 2.24 46.40 0.38 14.40 0.10 0.29 0.26 0.12 0.14 0.2 6.65 100.5 KN05-26 242.8 Massive Sulfide 16.8 1.8 4.653 0.46 0.09 84.90 0.05 0.07 0.06 0.01 0.32 0.01 0.01 0.14 13.05 99.20 KN05-26 249.31 Semi Massive Sulfide 0.9 0.1 3.305 18.05 5.16 49.00 0.15 0.33 0.23 0.93 0.69 0.19 0.16 0.15 7.49 82.50 KN05-26 254.2 Massive Sulfide 111.4 4.7 4.585 3.60 0.42 78.00 0.07 0.55 0.04 0.07 0.36 0.02 0.03 0.26 15.55 99.00 KN05-30 126.8 Semi Massive Sulfide 463.8 25.6 3.713 13.05 0.38 58.30 0.23 3.86 0.08 0.03 0.10 0.06 0.04 0.01 21.50 97.60 KN05-30 270.2 Peridotite 18.4 6.9 3.713 44.49 6.20 16.68 2.88 25.00 0.55 0.17 0.48 0.14 0.17 0.02 3.11 99.89 KN05-30 298.6 Massive Sulfide 108.4 9.4 4.646 3.56 0.25 67.20 0.04 2.70 0.01 0.01 0.37 0.02 0.05 0.01 9.02 83.20 KN05-33 369 Massive Sulfide 83.8 18.4 4.711 0.54 0.07 70.80 0.02 0.15 0.01 0.00 0.01 0.00 0.01 0.09 11.35 83.10 KN05-33 381.5A Semi Massive Sulfide 60.8 15.4 4.107 20.50 6.49 58.80 0.33 1.72 0.06 0.03 0.02 0.15 0.12 0.13 9.81 98.20 0 0 Sample Rock Type Average KN05-33 401 Massive Sulfide 60.8 KN97-08B 591.9 Semi Massive Sulfide 587.8 KN97-08B 594.6 Semi Massive Sulfide 59.5 KN97-08B 595 Semi Massive Sulfide 59.5 KN97-08B612 Diabase 0.6 KN98-56 166.55 Diabase 53.7 KN98-56 201.8 Sedimentary 0.1 KN98-56 209.3 Diabase 0.5 KN98-56 237.55 Pyroxenite 100.0 KN98-56 262.8 Peridotite 60.4 KN98-56 277.6 Peridotite 80.3 KN98-56 292.95 Peridotite 108.4 KN98-56 295.05 Massive Sulfide 64.7 KN98-56 299.35 Pyroxenite 18.1 KN98-56 309.95 Diabase 6.6 KN98-56 312.03 Massive Sulfide 114.0 KN98-56 313.45 Peridotite 109.2 KN98-56 321.7 Peridotite 79.2 KN98-56 337 Pyroxenite 12.6 KN98-56 343.05 Peridotite 53.5 KN98-56 346.8 Peridotite 38.4 KN98-56 352.05 Peridotite 7.2 KN98-56 374.05 Gabbro 30.5 KN98-56 392.03 Gabbro 1.6 KN98-56 417.6 Peridotite 90.7 KN98-56 447.45 Sedimentary 2.0 KN98-56 468.5 Sedimentary 5.7 KN98-56 485.56 Peridotite 171.7 KN98-56 497.6 Sedimentary 2.2 KN98-56 506.6 Diabase 0.9 KN98-56 507 Sedimentary 2.5 KN98-56 526.6 Sedimentary 0.3 KN98-56 541.6 Peridotite 0.2 KN98-56 561.1 Sedimentary 23.9 KN98-56 594.75 Sedimentary 2.1 Magnetic Susceptibility (10* SI) Standard Density (g/cm3) Si02 AI203 Fe203 CaO MgO Na20 K20 Cr203 Ti02 MnO P205 LOI Total % % % % % % % % % % % % % 28.50 24.30 6.88 1.74 50.8 49.5 0.34 0.49 1.67 16.4 0.06 0.08 0.02 0.05 0.02 0.32 0.19 0.06 0.12 0.21 0.26 0.1 8.82 7.35 97.7 100.5 15.4 91.4 5.6 5.6 0.2 0.0 0.0 4.9 5.9 6.2 2.9 9.9 27.4 3.9 2.0 6.3 0.2 0.3 1.6 0.3 0.1 0.1 0.0 0.5 4.107 3.813 3.478 3.805 2.868 2.900 2.842 2.925 2.980 2.922 2.833 2.870 2.927 2.888 3.210 3.810 2.870 2.888 3.270 2.957 2.848 3.400 3.554 3.723 2.960 2.782 2.772 2.920 2.825 3.010 2.740 2.928 2.740 2.880 2.795 21.30 36.64 48.94 61.18 51.69 38.73 39.74 36.49 32.57 35.31 44.71 50.98 5.13 26.96 29.96 30.71 34.29 29.81 38.51 33.20 30.40 39.36 69.85 60.13 38.81 40.51 47.81 61.03 64.24 57.68 61.47 60.63 1.78 16.40 13.45 20.20 9.90 6.38 4.32 3.73 3.07 2.77 5.57 4.56 0.71 1.02 1.79 2.97 2.95 2.63 4.04 3.68 4.00 4.60 15.17 17.12 3.61 31.66 10.24 18.18 17.56 20.01 18.19 21.01 56.10 15.40 15.59 3.91 9.51 17.53 12.75 15.30 19.56 19.39 14.84 11.82 75.29 29.62 25.19 34.55 16.92 23.00 25.44 33.90 40.50 13.24 6.01 9.61 17.46 15.40 13.24 4.97 6.46 7.35 10.44 7.11 1.44 0.22 8.23 0.92 6.67 2.68 1.71 1.85 1.24 1.39 2.84 2.14 0.19 0.10 0.70 1.69 1.56 1.24 2.69 2.77 2.67 3.39 0.61 1.42 2.11 0.14 5.16 3.50 0.28 0.46 0.29 0.23 9.62 17.17 4.03 2.59 16.16 25.08 32.29 30.85 30.87 29.98 24.53 27.03 4.14 27.92 29.79 21.27 30.44 29.61 22.91 17.50 14.00 30.58 1.40 1.70 28.06 1.12 15.80 2.76 1.59 3.17 1.50 1.41 0.08 0.27 2.40 1.80 0.55 0.28 0.3 0.21 0.38 0.29 0.74 0.57 0.09 0.17 0.17 0.28 0.32 0.35 0.35 0.26 0.33 0.34 0.71 1.58 0.19 3.31 0.41 5.44 1.00 1.21 0.97 0.98 0.04 8.45 1.47 3.69 0.14 0.23 0.44 0.22 0.27 0.13 0.62 0.50 0.05 0.08 0.21 0.15 0.17 0.11 0.13 0.05 0.19 0.23 2.67 3.13 0.03 2.49 0.17 0.38 3.70 4.06 2.76 3.41 0.13 0.12 0.01 0.04 0.29 0.30 0.22 0.27 0.37 0.45 0.34 0.58 0.25 0.38 0.37 0.29 0.18 0.38 0.71 0.43 0.46 0.27 0.02 0.02 0.34 0.03 0.26 0.04 0.01 0.05 0.01 0.01 0.10 0.75 3.74 0.90 0.54 0.27 0.19 0.15 0.17 0.10 0.78 0.30 0.04 0.07 0.13 0.12 0.12 0.09 0.15 0.12 0.15 0.23 0.79 0.81 0.18 0.71 0.54 0.90 0.71 0.92 0.82 0.91 0.12 0.06 0.18 0.03 0.16 0.08 0.12 0.14 0.15 0.18 0.15 0.14 0.04 0.16 0.21 0.18 0.14 0.15 0.14 0.19 0.13 0.14 0.02 0.03 0.15 0.01 0.19 0.04 0.03 0.03 0.03 0.04 0.10 0.01 0.56 0.08 0.03 0.04 0.02 0.03 0.02 0.01 0.10 0.03 0.00 0.01 0.02 0.01 0.01 0.02 0.01 0.12 0.13 0.03 0.08 0.04 0.03 0.03 0.04 0.05 0.04 0.05 0.04 0.06 9.58 4.24 I. 25 4.47 4.33 8.16 7.82 10.35 II. 15 9.99 4.57 I. 23 7.55 13.40 II. 40 7.69 12.25 12.15 4.76 5.37 6.08 7.44 2.49 3.87 8.92 4.45 6.02 2.50 4.16 4.80 3.15 4.05 100.5 99.89 99.95 99.92 99.99 99.78 99.93 99.59 99.82 99.98 99.81 99.88 93.48 99.88 99.94 99.91 99.35 99.56 99.84 97.60 99.10 99.84 99.86 99.55 99.89 99.9 99.87 99.85 99.86 99.87 99.72 99.93 Table L.2: Metal contents of the Kabanga samples, measured as ppm unless otherwise specified. SAMPLE Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) Ag As Co Cr Cu Fe % Mo Ni Pb S % V Zn Au Pt Pd K1B-06 395.26 Sedimentary 13.736 2.860 0.2 0 70 36 46 5.51 6 61 20 3.3 19 106 0.008 0 0.005 KN03-33 128.5 Diabase 0.482 2.802 0.3 0 39 1145 22 5.52 0 127 17 1.02 122 100 0.001 0 0.001 KN03-33 150.8 Sedimentary 0.560 2.820 0.3 12 63 37 105 6.89 1 61 5 3.13 35 49 0.008 0.005 0.001 KN03-33 152.4 Diabase 29.400 4.600 0.9 106 1430 67 3930 44.8 16 10000 30 6.28 14 46 0.004 0.071 0.048 KN03-33 161.9 Diabase 0.554 2.784 0.2 9 34 779 23 6.45 0 71 63 0.05 147 108 0.001 0 0 KN03-33 165.35A Diabase 0.448 3.051 2.7 104 554 1390 1285 10.1 1 10000 112 3.44 37 40 0.495 0.149 0.24 KN03-33 165.35B Diabase 0.448 3.051 22.9 19 81 83 10000 9.16 1 10000 19 5.52 69 218 0.077 0 0.002 KN03-33 168.2 Sedimentary 0.336 2.720 0 25 13 36 33 3.17 1 34 6 0.05 17 28 0.001 0 0.001 KN03-33 177.4 Sedimentary 0.316 2.821 0.3 4 43 107 116 10.1 1 942 10 0.35 39 21 0.009 0.009 0.014 KN03-33 178.0 Massive Sulfide 0.600 2.800 0 0 40 638 58 4.82 1 251 11 0.33 102 89 0.006 0 0 KN03-33 179.2 Massive Sulfide 31.680 4.671 1.4 41 2380 47 4930 50 13 10000 24 7.9 13 35 0.006 0.01 0.049 KN03-33 181.4 Semi Massive Sulfide 46.000 3.100 1.6 280 493 1170 572 23.3 5 5670 93 9.19 134 136 0.133 0.341 0.38 KN03-33 183.8 Semi Massive Sulfide 27.428 2.980 3.2 77 250 2110 493 12.85 1 2970 10000 4.65 161 333 0.035 0.185 0.165 KN03-33 196.85 Semi Massive Sulfide 612.600 3.311 1 218 773 242 1475 29.8 3 9310 86 6.91 34 50 0.218 0.273 0.631 KN03-33 206.25 Semi Massive Sulfide 346.600 3.193 0.9 461 701 113 1275 30 3 8080 100 6.39 20 25 0.414 0.473 1.615 KN03-33 206.8 Semi Massive Sulfide 542.691 3.350 1.6 836 1095 81 2450 36 4 10000 127 7.63 32 32 0.37 1.055 2.26 KN03-33 208.2 Semi Massive Sulfide 125.000 2.870 1 100 366 465 474 17.4 2 4470 45 3.28 . 48 430 0.044 0.134 0.157 KN03-33 211.45 Peridotite 90.420 2.841 0.4 98 269 620 442 10.7 0 3430 69 2.52 40 51 0.055 0.102 0.142 KN03-33 212.9 Peridotite 87.120 2.812 0.5 17 126 687 249 7.54 0 2840 92 0.97 43 50 0.033 0.065 0.103 KN03-33 224.45 Peridotite 104.773 2.790 0.3 4 53 520 38 4.51 0 1280 53 0.17 39 23 0:002 0.006 0.007 KN03-33 233.4 Pyroxenite 84.220 2.980 1.5 68 215 597 979 6.7 0 5360 62 1.12 26 52 0.042 0.172 0.249 KN03-33 240.5 Peridotite 141.000 2.858 KN03-33 246.9 Peridotite 175.357 2.800 0.2 6 93 640 86 6.12 0 1365 46 0.34 31 24 0.006 0.025 0.027 KN03-33 249.05 Peridotite 251.800 2.872 0.8 118 263 837 636 10.4 1 5780 60 2.13 34 25 0.041 0.142 0.213 KN03-33 250.9 Peridotite 135.000 2.797 0.5 12 100 1120 220 6.9 0 2490 30 0.32 43 18 0.016 0.018 0.029 KN03-33 251.6 Pyroxenite 326.000 2.860 1 36 241 856 477 8.68 1 5290 41 1.5 43 29 0.025 0.04 0.1 KN03-33 263.05 Peridotite 102.392 2.810 0 0 88 640 71 6 0 1415 45 0.19 33 21 0.005 0.018 0.005 KN03-33 265.5 Pyroxenite 37.500 3.106 0 4 114 679 105 6.32 1 2360 6 0.28 35 12 0.013 0.015 0.012 KN03-33 269.4 Pyroxenite 99.000 2.830 0 0 109 631 112 6.08 1 2100 51 0.34 32 32 0.005 0.01 0.013 KN03-33 289.05 Pyroxenite 0.660 3.270 0 2 37 1250 83 1.91 0 833 23 0.13 38 33 0.005 0.023 0.014 KN03-33 299.4 Pyroxenite 88.488 2.830 0 5 70 2280 59 4.6 0 1130 3 0.4 65 25 0.003 0.03 0.026 KN03-33 305.8 Gabbro 2.282 2.938 0.8 0 54 883 714 3.31 0 538 43 0.64 50 41 0.002 0 0.002 KN03-33 309.4 Gabbro 0.600 2.900 0 0 24 737 32 2.59 . 1 179 7 0.02 42 32 0.005 0 0.001 KN03-33 323.35 Sedimentary 4.558 2.880 0 0 9 96 39 3.45 1 61 10 1.62 21 13 0.002 0 0.001 O N o SAMPLE Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) Ag As Co Cr Cu Fe Mo Ni Pb S V Zn Au Pt Pd KN03-33 401 Massive Sulfide 45.240 4.553 0.8 79 1155 35 1650 50 17 10000 0 5.85 18 10 0.011 0.022 0.056 KN05-02 767.7 Massive Sulfide 43.633 4.598 1.5 260 1760 302 3820 50 17 10000 49 6.42 41 15 0.064 0.669 0.293 KN05-02 771.9 Semi Massive Sulfide 143.400 3.648 0.7 122 703 2080 1505 27.7 6 10000 84 6.67 193 39 0.167 0.11 0.29 KN05-03 177.3 Peridotite 56.633 2.858 0.4 41 221 270 474 10.65 1 3160 71 2.4 17 68 0.035 0.075 0.064 KN05-03 294.3 Massive Sulfide 20.140 4.585 2.2 88 1910 166 5530 50 12 10000 0 6.7 36 12 0.02 0.039 0.168 KN05-05 165 Peridotite 3.306 3.033 0 11 155 646 376 5.41 2 2480 14 2.49 57 17 0.007 0.024 0.016 KN05-07 351.2 Gabbro 0.533 2.690 0 0 33 1115 64 2.56 1 361 3 0.3 83 24 0.002 0 0.002 KN05-07 387.3 Sedimentary 5.757 2.837 0 4 22 229 93 4.44 1 212 8 1.3 28 28 0.008 0 0.001 KN05-11 390 Sedimentary 2.365 2.846 0 4 102 287 195 5.09 1 1230 16 1.88 45 23 0.009 0.008 0.016 KN05-12 390.1 Massive Sulfide 165.987 4.528 1.1 68 2370 149 5410 50 21 10000 0 9.57 36 7 0.009 0 0.154 KN05-21 393.4A Quartzite 14.370 2.655 0.2 0 7 228 14 0.74 1 94 2 0.13 2 2 0.002 0 0.001 KN05-21 393.4B Schist 0.017 2.655 0 3 68 70 179 8.28 3 888 3 4.59 12 34 0 0 0.006 KN05-23 245.8 Semi Massive Sulfide 19.217 3.813 0.4 24 792 156 946 41.3 16 8770 15 10 25 4 0.007 0 0.011 KN05-26 237.85 Semi Massive Sulfide 0.988 3.603 3 134 774 252 4570 28 7 9660 82 10 26 18 0.026 0.101 0.165 KN05-26 242.8 Massive Sulfide 16.780 4.653 0.9 61 1650 55 2840 50 25 10000 0 6.16 15 11 0.005 0.023 0.05 KN05-26 249.31 Semi Massive Sulfide 0.880 3.305 4.5 106 1605 358 10000 41.2 34 10000 38 10 51 45 0.013 0.018 0.092 KN05-26 254.2 Massive Sulfide 111.400 4.585 1.1 83 1515 95 3320 50 21 10000 0 10 21 11 0.009 0 0.093 KN05-30 126.8 Semi Massive Sulfide 463.800 3.713 0.7 202 1255 225 783 44.6 4 4140 13 10 46 0 0.008 0 0.006 KN05-30 270.2 Peridotite 18.372 3.713 0.4 50 158 400 766 6.34 1 1985 73 2.82 25 22 0.011 0.009 0.039 KN05-30 298.6 Massive Sulfide 108.400 4.646 3.1 89 3700 94 10000 50 44 10000 0 9.71 24 16 0.022 0.022 0.037 KN05-33 369 Massive Sulfide 83.840 4,711 8 1535 5140 3 9880 50 5 10000 1495 6.3 12 13 1.46 1.93 4.72 KN05-33 381.5A Semi Massive Sulfide 60.840 4.107 1.9 21 986 29 4240 48.1 4 10000 0 7.34 32 ' 80 0.207 0.061 0.175 KN05-33 401 Massive Sulfide 60.840 4.107 2.8 34 1110 39 3690 40 3 10000 23 7.27 35 87 0.122 0.065 0.205 KN97-08B 591.9 Semi Massive Sulfide 587.800 3.813 0.4 176 659 406 1400 38.2 5 7900 275 8.87 47 68 0.072 0.311 0.228 KN97-08B 595 Semi Massive Sulfide 59.540 3.805 1 146 995 557 2120 37.1 8 10000 180 10 78 0 0.336 0.139 0.357 KN97-08B612 Diabase 0.584 2.868 0 5 102 1050 54 10.5 0 1845 11 0.31 258 115 0.004 0.01 0.005 KN98-56 166.55 Diabase 53.653 2.900 0 0 18 28 367 5.49 1 29 3 0.05 199 263 0.007 0.006 0.02 KN98-56 201.8 Sedimentary 0.116 2.842 0 2 24 131 53 2.35 2 439 6 0.41 23 360 0.004 0.005 0.006 KN98-56 209.3 Diabase 0.514 2.925 0 0 26 1030 19 2.94 0 166 7 0.11 50 277 0.002 0 0 KN98-56 237.55 Pyroxenite 99.991 2.980 0.2 20 222 1065 268 10.1 2 2660 8 3.18 84 46 0.007 0.02 0.015 KN98-56 262.8 Peridotite 60.360 2.922 0.2 6 129 434 158 6.81 1 2020 27 1.12 25 39 0.008 0.022 0.014 KN98-56 277.6 Peridotite 80.280 2.833 0.4 16 165 359 429 9.08 1 2150 35 2.01 20 68 0.013 0.035 0.016 KN98-56 292.95 Peridotite 108.430 2.870 0.3 9 261 510 461 12.45 3 2950 25 3.54 34 77 0.008 0.006 0.011 KN98-56 295.05 Massive Sulfide 64.680 2.927 0.6 46 246 456 328 11.4 1 2630 96 3.14 35 82 0.114 0.072 0.079 KN98-56 299.35 Pyroxenite 18.120 2.888 0.4 26 133 490 332 6.82 2 1815 91 2.15 58 135 0.029 0.046 0.034 KN98-56 309.95 Diabase 6.629 3.210 0.2 10 81 502 238 2.98 1 1355 18 1.46 28 38 0.002 0.025 0.013 KN98-56 312.03 Massive Sulfide 114.000 3.810 1.2 89 2160 73 3460 40.1 14 10000 47 6.49 18 103 0.016 0.012 0.06 KN98-56 313.45 Peridotite 109.180 2.870 1.1 102 445 343 1445 21.4 5 5360 117 5.6 36 96 0.038 0.012 0.04 ON SAMPLE Rock Type Magnetic Susceptibility (10 SI) Density (g/cm3) Ag As Co Cr Cu Fe Mo Ni Pb S V Zn Au Pt Pd KN98-56 321.7 Peridotite 79.240 2.888 3.5 69 298 356 658 17.5 4 3760 1010 4.42 28 80 0.2 0.174 0.148 KN98-56 337 Pyroxenite 12.562 3.270 0.7 49 522 366 1760 22.1 5 6800 26 7.24 32 44 0.009 0.013 0.021 KN98-56 343.05 Peridotite 53.500 2.957 0.7 63 187 559 265 10.8 1 2220 139 2.45 42 77 0.019 0.093 0.039 KN98-56 346.8 Peridotite 38.380 2.848 0.2 18 269 336 366 16.2 3 3140 62 3.99 27 88 0.015 0.017 0.04 KN98-56 352.05 Peridotite 7.212 3.400 0.4 44 393 372 472 13.9 5 5030 52 6.75 21 33 0.003 0.051 0.028 KN98-56 374.05 Gabbro 30.520 3.554 1.2 68 756 301 870 21.9 8 10000 187 9.52 24 30 0.027 0.066 0.053 KN98-56 392.03 Gabbro 1.564 3.723 0.5 63 756 297 740 25.6 26 10000 42 10 25 9 0.013 0 0.031 KN98-56 417.6 Peridotite 90.736 2.960 2.3 24 130 323 310 6.83 1 2810 536 1.12 27 25 0.076 0.166 0.136 KN98-56 447.45 Sedimentary 2.020 2.782 0.2 4 35 56 73 3.68 1 383 14 1.15 23 47 0.003 0 0.002 KN98-56 468.5 Sedimentary 5.682 2.772 0.2 4 43 40 159 6.46 3 357 15 3.2 36 82 0.006 0 0.001 KN98-56 485.56 Peridotite . 171.696 2.920 0.2 0 141 1265 213 10.05 1 1165 10 2.57 91 50 0 0 0.004 KN98-56 497.6 Sedimentary 2.212 2.825 0.3 3 102 48 245 10.95 2 638 13 4.66 48 62 0.004 0 0.004 KN98-56 506.6 Diabase 0.922 3.010 0 0 44 1120 37 6.06 1 241 4 0.93 95. 402 0.002 0 0.001 KN98-56 507 Sedimentary 2.500 2.740 0.2 0 13 205 50 3.38 0 98 30 0.76 97 61 0.002 0 0.002 KN98-56 526.6 Sedimentary 0.260 2.928 0 0 21 33 49 4.44 1 71 6 1.74 21 155 0.003 0 0.001 KN98-56 541.6 Peridotite 0.240 2.740 0.2 3 34 87 93 4.78 2 317 20 2.44 22 149 0.004 0 0.004 KN98-56 561.1 Sedimentary 23.891 2.880 0.2 4 32 52 56 7.53 1 91 21 3.15 28 118 0.002 0 0 KN98-56 594.75 Sedimentary 2.132 2.795 0 0 52 36 25 4.55 1 40 6 1.6 38 296 0.004 0 0.001 Table L.3: Additional geochemical analyses for the Kabanga rock samples, focusing on parameters that may indicate alteration. SAMPLE Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) H20* % H20-% FeO % C % co 2 % KN03-33 152.4 Diabase 29.400 4.600 3.4 5.22 <0.05 <0.2 KN03-33 165.35A Diabase 0.448 3.051 9.05 0.32 6.58 <0.05 0.2 KN03-33 178.0 Massive Sulfide 0.600 2.800 4.79 0.33 <0.05 <0.2 KN03-33 179.2 Massive Sulfide 31.680 4.671 3.27 4.45 <0.05 <0.2 KN03-33 183.8 Semi Massive Sulfide 27.428 2.980 7.48 0.17 16.85 <0.05 <0.2 KN03-33 196.85 Semi Massive Sulfide 612.600 3.311 7.14 1.22 19.95 <0.05 <0.2 KN03-33 212.9 Peridotite 87.120 2.812 8.9 0.44 6.2 <0.05 <0.2 KN03-33 249.05 Peridotite 251.800 2.872 9.45 0.37 7.38 <0.05 <0.2 KN03-33 251.6 Pyroxenite 326.000 2.860 9.74 0.33 6.13 <0.05 <0.2 KN03-33 263.05 Peridotite 102.392 2.810 8.18 0.32 5.39 <0.05 <0.2 KN03-33 269.4 Pyroxenite 99.000 2.830 8.18 0.32 5.39 <0.05 <0.2 KN03-33 289.05 Pyroxenite 0.660 3.270 5 0.23 6.91 <0.05 <0.2 KN03-33 305.8 Gabbro 2.282 2.938 3.75 0.17 7.71 <0.05 <0.2 KN03-33 309.4 Gabbro 0.600 2.900 3.72 0.21 7.67 <0.05 <0.2 KN05-02 771.9 Semi Massive Sulfide 143.400 3.648 2.87 0.6 39.5 <0.05 <0.2 KN05-05 165 Peridotite 3.306 3.033 1.02 0.7 10.75 O.05 <0.2 KN05-07 351,2 Gabbro 0.533 2.690 2.79 0.18 7.06 <0.05 <0.2 KN05-12 390.1 Massive Sulfide 165.987 4.528 2.5 5.84 48.2 O.05 <0.2 KN05-26 237.85 Semi Massive Sulfide 0.988 3.603 5.38 2.93 20.1 <0.05 ' <0.2 KN05-26 249.31 Semi Massive Sulfide 0.880 3.305 2.72 3.32 24.4 <0.05 <0.2 KN05-26 254.2 Massive Sulfide 111.400 4.585 4.63 4.97 22.3 <0.05 <0.2 KN05-30 126.8 Semi Massive Sulfide 463.800 3.713 2.52 2 0.29 1.1 KN05-30 270.2 Peridotite 18.372 3.713 1.76 0.59 12.5 <0.05 <0.2 KN05-33 381 5A Semi Massive Sulfide 60.840 4.107 4.5 2.16 23.4 O.05 <0.2 KN05-33 401 Massive Sulfide 60.840 4.107 5.11 3.39 22.2 <0.05 <0.2 KN97-08B 612 Diabase 0.584 2.868 3.38 0.23 12.95 <0.05 <0.2 KN98-56 166.55 Diabase 53.653 2.900 0.91 1.02 9.2 <0.05 <0.2 KN98-56 262.8 Peridotite 60.360 2.922 6.79 0.5 9.45 <0.05 <0.2 KN98-56 299.35 Pyroxenite 18.120 2.888 3.12 0.71 9.72 <0.05 <0.2 KN98-56 309.95 Diabase 6.629 3.210 0.86 0.25 9.6 <0.05 <0.2 KN98-56 312.03 Massive Sulfide 114.000 3.810 1.4 0.36 59.4 <0.05 <0.2 KN98-56 313.45 Peridotite 109.180 2.870 9.11 0.77 8.42 <0.05 <0.2 KN98-56 321.7 Peridotite 79.240 2.888 7.92 0.35 7.18 0.06 0.2 KN98-56 337 Pyroxenite 12.562 3.270 3.87 0.5 27.7 <0.05 <0.2 KN98-56 343.05 Peridotite 53.500 2.957 9.39 0.53 8.03 0.09 0.3 SAMPLE Rock Type Magnetic Susceptibility (10* Si) Density (g/cm3) H20* % H20-% FeO % c % co 2 % KN98-56 352.05 Peridotite 7.212 3.400 1.22 0.13 29 <0.05 <0.2 KN98-56 374.05 Gabbro 30.520 3.554 1.19 0.09 33.1 <0.05 <0.2 KN98-56 506.6 Diabase 0.922 3.010 5.53 0.57 9.48 <0.05 <0.2 KN98-56 541.6 Peridotite 0.240 2.740 3.07 0.35 3.46 <0.05 <0.2 O S Appendix M; Data for Quantitative Estimation of Serpentinization and Physical Properties Table M . l : Data used for testing quantitative relationships between physical properties and degree of serpentinization using the Kabanga samples. % serpentine was quantified petrographically. Serpentine content was estimated from density (% serpentine estimated) and density was estimated from serpentine content (% S). The misfit on density was calculated as Density(estimated) - Density (measured), and was divided by the measured density to calculate the misfit as a percent. Susceptibility was calculated from density and misfits were calculated similarly. SAMPLE Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) % Serpentine %S estimated from density Density estimated from %S Misfit on Density Density Misfit as % Susceptibility estimated from Density (10"3SI) Misfit on Sus. Misfit Sus. as % KN03-33 183.8 Semi Massive Sulfide 27.428 2.980 25 38 3.08 -0.10 -3.26 1.90 25.52 93.06 KN03-33 196.85 Semi Massive Sulfide 612.600 3.311 49 -6 2.90 0.41 12.48 4.26 608.34 99.30 KN03-33 206.25 Semi Massive Sulfide 346.600 3.193 45 10 2.93 0.27 8.31 3.73 342.87 98.92 KN03-33 206.8 Semi Massive Sulfide 542.691 3.350 44 -11 2.93 0.42 12.39 3.61 539.09 99.34 KN03-33 208.2 Semi Massive Sulfide 125.000 2.870 40 53 2.96 -0.09 -3.30 3.15 121.85 97.48 KN03-33 211.45 Peridotite 90.420 2.841 40 53 2.96 -0.12 -4.36 3.15 87.27 96.51 KN03-33 212.9 Peridotite 87.120 2.812 56 57 2.85 -0.03 -1.18 5.40 81.72 93.81 KN03-33 224.45 Peridotite 104.773 2.790 60 60 2.82 -0.03 -0.90 6.17 98.60 94.11 KN03-33 233.4 Pyroxenite 84.220 2.980 65 38 2.78 0.20 6.79 7.30 76.92 91.33 KN03-33 240.5 Peridotite 141.000 2.858 65 38 2.78 0.08 2.81 7.30 133.70 94.82 KN03-33 246.9 Peridotite 175.357 2.800 60 54 2.82 -0.02 -0.54 6.17 169.19 96.48 KN03-33 249.05 Peridotite 251.800 2.872 70 62 2.74 0.13 4.58 8.63 243.17 96.57 KN03-33 250.9 Peridotite 135.000 2.797 60 52 2.82 -0.02 -0.64 6.17 128.83 95.43 KN03-33 251.6 Pyroxenite 326.000 2.860 65 54 2.78 0.08 2.87 7.30 318.70 97.76 KN03-33 263.05 Peridotite 102.392 2.810 60 54 2.82 -0.01 -0.19 6.17 96.22 93.97 KN03-33 265.5 Pyroxenite 37.500 3.106 70 21 2.74 0.37 11.78 8.63 28.87 76.98 KN03-33 269.4 Pyroxenite 99.000 2.830 65 58 2.78 0.05 1.84 7.30 91.70 92.63 KN03-33 289.05 Pyroxenite 0.660 3.270 18 -1 3.13 0.14 4.30 1.51 -0.85 -128.14 KN03-33 299.4 Pyroxenite 88.488 2.830 35 58 3.00 -0.17 -6.08 2.67 85.82 96.99 KN03-33 305.8 Gabbro 2.282 2.938 0 44 3.26 -0.33 -11.11 0.82 1.46 63.95 KN03-33 309.4 Gabbro 0.600 2.900 0 49 3.26 -0.36 -12.55 0.82 -0.22 -37.10 KN05-02 771.9 Semi Massive Sulfide 143.400 3.648 10 -51 3.19 0.46 12.58 1.15 142.25 99.20 KN05-03 177.3 Peridotite 56.633 2.858 30 -51 3.04 -0.18 -6.34 2.25 54.38 96.02 KN05-05 165 Peridotite 3.306 3.033 2 54 3.25 -0.22 -7.14 0.88 2.43 73.39 KN05-07 351.2 Gabbro 0.533 2.690 5 77 3.23 -0.54 -19.93 0.97 -0.44 -82.44 KN05-23 245.8 Semi Massive Sulfide 19.217 3.813 0 -73 3.26 0.55 14.39 0.82 18.39 95.72 KN05-26 237.85 Semi Massive Sulfide 0.988 3.603 8 -45 3.20 0.40 11.07 1.08 -0.09 -8.93 KN05-26 249.31 Semi Massive Sulfide 0.880 3.305 0 -6 3.26 0.04 1.28 0.83 0.05 6.21 OS SAMPLE Rock Type Magnetic Susceptibility (10* SI) Density (g/cm3) % Serpentine %S estimated from density . Density estimated from %S Misfit on Density Density Misfit as % Susceptibility estimated from Density (10°SI) Misfit on Sus. Misfit Sus. as % KN05-30 126.8 Semi Massive Sulfide 463.800 3.713 7 -60 3.21 0.50 13.50 1.04 462.76 99.78 KN05-30 270.2 Peridotite 18.372 3.713 2 -60 3.25 0.46 12.50 0.88 17.49 95.21 KN05-33 381.5A Semi Massive Sulfide 60.840 4.107 56 -113 2.85 1.26 30.72 5.40 55.44 91.13 KN97-08B 594.6 Semi Massive Sulfide 59.540 3.478 10 -29 3.19 0.29 8.31 1.15 58.39 98.07 KN97-08B 595 Semi Massive Sulfide 59.540 3.805 29 -72 3.05 0.76 19.90 2.17 57.37 96.35 KN98-56 237.55 Pyroxenite 99.991 2.980 35 38 3.00 -0.02 -0.74 2.67 97.33 97.33 KN98-56 262.8 Peridotite 60.360 2.922 50 38 2.89 0.03 1.10 4.41 55.95 92.69 KN98-56 292.95 Peridotite 108.430 2.870 35 46 3.00 -0.13 -4.61 2.67 105.77 97.54 KN98-56 299.35 Pyroxenite 18.120 2.888 6 50 3.22 -0.33 -11.48 1.01 17.11 94.45 KN98-56 313.45 Peridotite 109.180 2.870 70 50 2.74 0.13 4.52 8.63 100.55 92.09 KN98-56 321.7 Peridotite 79.240 2.888 65 53 2.78 0.11 3.83 7.30 71.94 90.79 KN98-56 337 Pyroxenite 12.562 3.270 24 -1 3.08 0.19 5.67 1.84 10.72 85.34 KN98-56 343.05 Peridotite 53.500 2.957 33 -1 3.02 -0.06 -2.02 2.49 51.01 95.34 KN98-56 346.8 Peridotite 38.380 2.848 25 41 3.08 -0.23 -8.03 1.90 36.48 95.04 KN98-56 352.05 Peridotite 7.212 3.400 8 56 3.20 0.20 5.76 1.08 6.14 85.08 KN98-56 374.05 Gabbro 30.520 3.554 0 -39 3.26 0.29 8.15 0.82 29.70 97.30 KN98-56 392.03 Gabbro 1.564 3.723 0 -61 3.26 0.46 12.32 0.82 0.74 47.40 KN98-56 417.6 Peridotite 90.736 2.960 35 -61 3.00 -0.04 -1.43 2.67 88.07 97.06 KN98-56 485.56 Peridotite 171.696 2.920 23 41 3.09 -0.17 -5.89 1.78 169.92 98.96 KN98-56 541.6 Peridotite 0.240 2.740 7 46 3.21 -0.47 -17.21 1.04 -0.80 -333.60 0 \ ON Appendix N: Correlation Analysis Results for Kabanga Samples. Table N.l: Correlations between various geological and geophysical properties for Kabanga. Significant correlations appear in bold. Depth Ore Body Rock Type MS Density Si02 Fe203 MgO Mg# LOI Co Cu Fe Ni S Au Pt Pd Amph CPX OPX Ol Serp Pyrr Pent Cpy Depth (m) 1 Ore Body -0.034 1 Rock Type 0.117 0.022 1 Magsus -0.039 0.267 0.312 1 Density 0.203 -0.034 0.484 0.012 1 S02 -0.127 -0.026 -0.633 -0.237 -0.834 1 Fe203 0.183 -0.025 0.578 0.158 0.921 -0.932 1 MgO -0.178 0.090 -0.248 0.131 -0.731 0.495 -0.730 1 Mg# -0.191 0.075 -0.448 -0.068 -0.830 0.732 -0.897 0.912 1 LOI -0.169 0.124 0.452 0.380 0.323 -0.634 0.449 -0.039 -0.253 1 Co 0.100 -0.009 0.528 0.077 0.819 -0.809 0.797 -0.619 -0.724 0.357 1' Cu 0.016 0.013 0.338 -0.062 0.647 -0.571 0.618 -0.645 -0.710 0.199 0.778 1 Fe 0.170 -0.013 0.623 0.224 0.895 -0.922 0.973 -0.723 -0.902 0.501 0.814 0.663 1 Ni 0.149 0.093 0.454 0.194 0.762 -0.783 0.836 -0.559 -0.792 0.367 0.678 0.688 0.845 1 S 0.147 -0.165 0.502 0.204 0.698 -0.706 0.798 -0.588 -0.813 0.337 0.599 0.564 0.839 0.846 1 Au 0.086 0.265 0.211 0.164 0.280 •0.316 0.269 -0.155 -0.251 0.175 0.584 0.393 0.312 0.361 0.213 1 Ft 0.132 0.284 0.303 0.296 0.307 -0.370 0.314 -0.155 -0.259 0.178 0.582 0.360 0.351 0.332 0.220 0.874 1 Pd 0.033 0.246 0.273 0.278 0.286 -0.336 0.290 -0.167 -0.257 0.161 0.599 0.384 0.332 0.319 0.206 0.923 0.954 1 Amph 0.023 0.302 -0.443 -0.136 -0.174 0.277 -0.204 0.061 0.220 -0.205 -0.258 -0.268 -0.266 -0.319 4.282 -0.149 -0.161 -0.153 1 CPX -0.029 -0.099 4.264 -0.003 -0.282 0.310 -0.343 0.249 0.281 -0.266 -0.295 -0.303 -0.350 •0.359 -0.313 -0.180 -0.146 -0.157 -0.025 1 OPX 0.111 -0.502 -0.132 -0.227 -0.140 0.323 •0.263 0.220 0.233 -0.383 -0.237 -0.240 •0.280 -0.219 -0.051 -0.161 -0.145 -0.151 -0.246 0.172 1 Ol -0.004 -0.388 0.011 -0.120 -0.203 0.096 -0.171 0.262 0.198 0.014 -0.158 -0.159 -0.167 -0.171 -0.084 -0.075 -0.074 -0.090 -0.186 0.169 0.452 1 Serp -0.135 0.282 0.073 0.332 4.426 0.130 -0.350 0.649 0.513 0.324 -0.314 -0.313 -0.289 -0.204 -0.325 -0.026 0.002 0.004 -0.095 0.183 -0.110 0.105 1 Pyrr -0.016 -0.106 0.663 -0.003 0.731 -0.684 0.743 -0.653 -0.724 0.292 0.760 0.614 0.768 0.623 0.614 0.259 0.201 0.280 -0.325 -0.326 -0.239 -0.163 -0.342 1 Pent -0.149 0.172 0.400 0.004 0.176 -0.165 0.199 -0.215 -0.205 0.015 0.319 0.221 0.192 0.171 0.103 0.318 0.291 0.340 -0.245 •0.253 -0.128 -O.130 -0.111 0.501 1 Cpy -0.083 0.110 0.342 0.011 0.372 -0.309 0.380 -0.338 -0.432 0.134 0.288 0.411 0.424 0.471 0.462 0.221 0.128 0.164 -0.193 •0.331 -0.126 -0.135 -0.167 0.437 0.280 1 Mag -0.200 0.344 0.180 0.674 -0.198 -0.050 -0.041 0.254 0.108 0.275 -0.090 -0.199 0.002 -0.014 -0.021 0.109 0.198 0.219 0.030 0.046 -0.240 -0.144 0.474 -0.113 0.140 0.039 Os - J Appendix O: Results of Mineral Prediction Filter calculations for Kabanga Samples Table O. l : Chart comparing the ore mineral contents estimated modally during petrographical analysis for the Kabanga samples to the mineral abundances calculated for the minimized and maximized sulfide versions of the Mineral Prediction Filter. The ore column refers to the samples identified by the program as having anomalous amounts of sulfide or oxide minerals. Abbreviations are as follows: Po = pyrrhotite, (H) = hexagonal pyrrhotite, (M) = monoclinic pyrrhotite, pn = pentlandite, py = pyrite, mgt = magnetite, host = host rock. Modal Abundances Mineral Abundances Calculated: Mineral Abundances Calculated: Drillhole Depth (m) Rock Type Minimized Sulfides Maximized Sulfides ORE? Po Pn Py Mgt Mgt Po Po (H) Po (M) Po Py Host Mgt Pn Po(H) Po (M) Po Py Host KN03-33 128.5 Diabase 0 0 0.035 0.035 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.02 0.04 0.00 0.04 0.00 0.93 KN03-33 152.4 Diabase 0 0 0 0.015 0.01 0.15 0.57 0.00 0.57 0.15 0.11 0.00 0.15 0.77 0.01 0.78 0.00 0.07 YES KN03-33 161.9 Diabase 0 0 0 0.05 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.02 0.04 0.00 0.04 0.00 0.94 KN03-33 165.35 Diabase 0.03 0.02 0 0 0.00 0.00 0.00 0.00 0.00 0.01 0.99 0.00 0.07 0.13 0.00 0.13 0.00 0.80 KN97-08B 612 Diabase 0 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.03 0.07 0.00 0.07 0.00 0.90 KN98-56 225.65 Diabase 0.37 0.01 0 0 0.00 0.00 0.00 0.00 0.00 0.09 0.91 0.00 0.09 0.19 0.00 0.19 0.00 0.72 YES KN98-56 309.95 Diabase 0.07 0.01 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.09 0.00 0.09 0.00 0.87 KN98-56 461.4 Diabase 0.002 0 0 0.005 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.06 0.12 0.00 0.12 0.00 0.82 KN98-56 506.6 Diabase 0 0 0.015 0.015 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.05 0.03 0.08 0.00 0.88 KN98-56 166.55 Diabase 0 0 0 0.06 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 . 0.09 0.00 0.09 0.00 0.86 KN98-56 209.3 Diabase 0 0 0 0 0.02 0.03 0.06 0.00 0.06 0.15 0.73 0.00 0.15 0.28 0.02 0.30 0.00 0.55 YES KN03-33 293.4 Gabbro 0.05 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.09 0.00 0.09 0.00 0.87 KN03-33 305.8 Gabbro 0.02 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.03 0.05 0.00 0.05 0.00 0.92 KN03-33 309.4 Gabbro 0 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.05 0.09 0.00 0.09 0.00 0.86 KN05-07 351.2 Gabbro 0.005 0 0 0.015 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.99 KN98-56 374.05 Gabbro 0.13 0.01 0 0 0.02 0.04 0.07 0.00 0.07 0.15 0.73 0.00 0.15 0.29 0.01 0.30 0.00 0.55 YES KN98-56 380.05 Gabbro 0.34 0.02 0 0.01 0.00 0.05 0.09 0.00 0.09 0.15 0.71 0.00 0.15 0.30 0.00 0.30 0.00 0.55 YES KN98-56 392.03 Gabbro 0.36 0.03 0 0 0.00 0.07 0.15 0.00 0.15 0.15 0.63 0.00 0.15 0.30 0.00 0.30 0.00 0.55 YES KN98-56 407 Gabbro 0.07 0.01 0 0.005 0.00 0.00 0.00 0.00 0.00 0.02 0.97 0.00 0.07 0.14 0.00 0.14 0.00 0.79 KN98-56 511.3 Gabbro 0.02 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.05 0.10 0.00 0.10 0.00 0.84 KN98-56 538.3 Gabbro 0.01 0 0 0.01 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.05 0.10 0.00 0.10 0.00 0.85 KN03-33 178.8 Massive Sulfide 0.67 0.3 0 0.02 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.02 0.05 0.00 0.05 0.00 0.93 0 0 Drillhole Depth (m) Rock Type Modal Abundances Observed During Petrography Mineral Abundances Calculated using Minimized Sulfides version of the Mineral Prediction Filter Mineral Abundances Calculated using Maximized Sulfides version of the Mineral Prediction Filter ORE? Po Pn Py Mgt Mgt Po Po (H) Po (M) Po Py Host Mgt Pn Po(H) Po (M) Po Py Host KN03-33 179.2 Massive Sulfide 0.9 0.07 0 0.01 0.02 0.15 0.60 0.00 0.60 0.15 0.08 0.00 0.15 0.80 0.01 0.81 0.00 0.04 YES KN05-03 294.3 Massive Sulfide 0.84 0.05 0 0.02 0.01 0.15 0.56 0.00 0.56 0.15 0.13 0.00 0.15 0.75 0.01 0.76 0.00 0.09 YES KN05-12 390.1 Massive Sulfide 0.94 0.02 0 0.015 0.05 0.15 0.00 0.47 0.47 0.15 0.18 0.00 0.15 0.64 0.08 0.73 0.00 0.12 YES KN05-26 242.8 Massive Sulfide 0.86 0.06 0.05 0.01 0.01 0.15 0.60 0.00 0.60 0.15 0.09 0.00 0.15 0.79 0.01 0.80 0.00 0.05 YES KN05-26 254.2 Massive Sulfide 0.84 0.03 0.1 0.01 0.05 0.15 0.38 0.13 0.51 0.15 0.14 0.00 0.15 0.71 0.06 0.76 0.00 0.09 YES KN05-30 298.6 Massive Sulfide 0.92 0.03 0.01 0.01 0.05 0.15 0.45 0.09 0.55 0.15 0.11 0.00 0.15 0.74 0.05 0.80 0.00 0.05 YES KN05-33 369 Massive Sulfide 0.8 0.14 0 0.02 0.04 0.15 0.59 0.00 0.59 0.15 0.07 0.00 0.15 0.79 0.04 0.83 0.00 0.01 YES KN05-33 401 Massive Sulfide 0.96 0.02 0 0 0.03 0.13 0.27 0.00 0.27 0.15 0.42 0.00 0.15 0.45 0.03 0.47 0.00 0.37 YES KN98-56 295.05 Massive Sulfide 0.915 0.03 0.02 0.015 0.05 0.14 0.29 0.00 0.29 0.15 0.37 0.00 0.15 0.48 0.05 0.53 0.00 0.32 YES KN98-56 312.03 Massive Sulfide 0.89 0.08 0 0.01 0.05 0.08 0.00 0.16 0.16 0.15 0.56 0.00 0.15 0.28 0.06 0.33 0.00 0.52 YES KN03-33 211.45 Peridotite 0.09 0.01 0 0.1 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.03 0.01 0.04 0.06 0.00 0.91 KN03-33 212.9 Peridotite 0.01 0.01 0 0.03 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.02 0.00 0.04 0.05 0.00 0.93 KN03-33 218.2 Peridotite 0.01 0.06 0 0.08 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.02 0.00 0.05 0.05 0.00 0.92 KN03-33 224.45 Peridotite 0.01 0.03 0 0.06 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.02 0.00 0.04 0.04 0.00 0.94 KN03-33 240.5 Peridotite 0.03 0.03 0 0.04 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.03 0.00 0.06 0.06 0.00 0.90 KN03-33 246.9 Peridotite 0 0.01 0 0.1 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.01 0.02 0.00 0.04 0.04 0.00 0.94 KN03-33 249.05 Peridotite 0.04 0.04 0 0.06 0.02 0.00 0.00 0.00 0.00 0.00 0.98 0.01 0.03 0.00 0.06 0.06 0.00 0.90 KN03-33 250.9 Peridotite 0 0.02 0 0.06 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.02 0.00 0.04 0.04 0.00 0.94 KN03-33 263.05 Peridotite 0.005 0.005 0 0.08 0.01 0.00 0.00 0.00 0.00 o:oo 0.99 0.00 0.02 0.00 0.05 0.05 0.00 0.93 KN05-03 177.3 Peridotite 0.06 0.01 0 0.01 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.03 0.04 0.03 0.06 0.00 0.90 KN05-05 165 Peridotite 0.01 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.06 0.13 0.00 0.13 0.00 0.81 KN05-30 270.2 Peridotite 0.07 0.01 0 0.01 0.01 0.07 0.14 0.00 0.14 0.15 0.64 0.00 0.15 0.29 0.01 0.30 0.00 0.55 YES KN98-56 262.8 Peridotite 0.02 0.01 0 0.04 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.06 0.03 0.09 0.00 0.87 KN98-56 271.3 Peridotite 0.04 0.01 0 0.02 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.05 0.07 0.02 0.09 0.00 0.86 KN98-56 289.4 Peridotite 0.06 0.01 0 0.03 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.07 0.01 0.08 0.00 0.87 KN98-56 292.95 Peridotite 0.03 0.01 0 0.02 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.03 0.01 0.05 0.07 0.00 0.90 KN98-56 296.05 Peridotite 0.1 0.02 0 0.03 0.01 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.04 0.06 0.03 0.09 o:oo 0.86 ON Drillhole Depth (m) Rock Type Modal Abundances Observed During Petrography Po Pn Py Mgt Mineral Abundances Calculated using Minimized Sulfides version of the Mineral Prediction Filter Mgt Po Po (H) Po (M) Po Py Host Mineral Abundances Calculated using Maximized Sulfides version of the Mineral Prediction Filter Mgt Pn Po (H) Po (M) Po Py Host 0.07 0.00 0.90 0.08 0.00 0.89 0.10 0.00 0.85 0.11 0.00 0.83 0.06 0.00 0.91 0.09 0.00 0.86 0.26 0.00 0.61 0.26 0.00 0.60 0.10 0.00 0.85 0.09 0.00 0.87 0.05 0.00 0.92 0.02 0.00 0.97 0.05 0.00 0.92 0.11 0.00 0.84 0.07 0.00 0.90 0.05 0.00 0.91 0.05 0.00 0.91 0.05 0.00 0.92 0.15 0.00 0.77 0.06 0.00 0.91 0.04 0.00 0.94 0.08 0.00 0.89 0.11 0.00 0.84 0.16 0.00 0.76 0.21 0.00 0.68 0.08 0.00 0.89 0.05 0.00 0.92 0.16 0.00 0.75 0.21 0.00 0.68 KN98-56 313.45 Peridotite 0.14 0.03 0 0.04 0 01 0.00 0.00 KN98-56 321.7 Peridotite 0.16 0.02 0 0.03 0 01 0.00 0.00 KN98-56 343.05 Peridotite 0.09 0.01 0.01 0.02 0 00 0.00 0.00 KN98-56 345.3 Peridotite 0 0 0 0 0 01 0.00 0.00 KN98-56 346.8 Peridotite 0.09 0.02 0 0.02 0 00 0.00 0.00 KN98-56 351.45 Peridotite 0.05 0.01 0 0.02 0 00 0.00 0.00 KN98-56 352.05 Peridotite 0.11 0.01 0 0.01 0 00 0.01 0.02 KN98-56 371.8 Peridotite 0.11 0.02 0 .0.02 0 05 0.00 0.00 KN98-56 417.6 Peridotite 0.02 0 0 0.02 0 01 0.00 0.00 KN98-56 485.56 peridotite 0.05 0 0 0.05 0 01 0.00 0.00 KN98-56 495.65 peridotite 0.05 0.01 0 0.03 0 00 0.00 0.00 KN98-56 541.6 peridotite 0.04 0.01 0 0.01 0 00 0.00 0.00 KN03-33 231.2 Pyroxenite 0.03 0.02 0 0.05 0 01 0.00 0.00 KN03-33 233.4 Pyroxenite 0.03 0.02 0 0.07 0 01 0.00 0.00 KN03-33 241.2 pyroxenite 0 0 0 0.07 0 01 0.00 0.00 KN03-33 251.6 Pyroxenite 0.005 0.005 0 0 0 03 0.00 0.00 KN03-33 251.6 Pyroxenite 0 0 0 0 0 03 0.00 0.00 KN03-33 257.8 Pyroxenite 0 0 0 0.03 0 01 0.00 0.00 KN03-33 265.5 Pyroxenite 0.02 0.02 0 0 0 02 0.00 0.00 KN03-33 269.4 Pyroxenite 0.02 0.02 0 0.06 0 01 0.00 0.00 KN03-33 272.1 Pyroxenite 0.03 0.01 0 0.01 0 01 0.00 0.00 KN03-33 282.7 Pyroxenite 0.04 0 0 0.04 0 01 0.00 0.00 KN98-56 237.55 Pyroxenite 0.12 0.02 0 0.01 0 01 0.00 0.00 KN98-56 254.8 Pyroxenite 0.12 0.02 0 0.02 0 01 0.00 0.00 KN98-56 289.05 Pyroxenite 0.05 0.03 0 0.02 0 00 0.00 0.00 KN98-56 299.35 Pyroxenite 0.17 0.03 0 0.02 0 00 0.00 0.00 KN98-56 299.4 Pyroxenite 0.06 0.005 0.02 0 0 01 0.00 0,00 KN98-56 309 Pyroxenite 0.01 0.005 0 0.01 0 04 0.00 0.00 KN98-56 337 Pyroxenite 0.25 0.03 0 0.01 0 01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.15 0.14 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.04 0.12 0.00 0.00 0.01 0.11 0.99 0.99 1.00 0.99 1.00 1.00 0.81 0.81 0.99 0.99 1.00 1.00 0.99 0.99 0.99 0.97 0.97 0.99 0.96 0.99 0.99 0.99 0.99 0.96 0.88 1.00 0.99 0.95 0.88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.04 0.05 0.06 0.03 0.05 0.13 0.13 0.05 0.04 0.03 0.01 0.02 0.05 0.03 0.02 0.03 0.03 0.08 0.03 0.02 0.04 0.05 0.08 0.11 0.04 0.03 0.08. 0.11 0.01 0.04 0.08 0.06 0.04 0.07 0.25 0.20 0.06 0.00 0.02 0.02 0.00 0.07 0.01 0.00 0.00 0.00 0.14 0.01 0.00 0.02 0.06 0.15 0.21 0.07 0.01 0.12 0.21 0.05 0.04 0.03 0.05 0.02 0.03 0.00 0.07 0.04 0.09 0.03 0.00 0.05 0.04 0.06 0.05 0.05 0.05 0.02 0.05 0.04 0.05 0.05 0.01 0.00 0.01 0.04 0.04 0.00 o Drillhole Depth (m) Rock Type Modal Abundances Observed During Petrography Mineral Abundances Calculated using Minimized Sulfides version of the Mineral Prediction Filter Mineral Abundances Calculated using Maximized Sulfides version of the Mineral Prediction Filter ORE? Po Pn Py Mgt Mgt Po Po(H) Po (M) Po Py Host Mgt Pn Po (H) Po (M) Po Py Host KN03-33 181.4 Semi Massive Sulfide 0.25 0.03 0 0.001 0.02 0.00 0.00 0.00 0.00 0.03 0.95 0.00 0.08 0.14 0.02 0.16 0.00 0.76 YES KN03-33 183.8 Semi Massive Sulfide 0.15 0.05 0.02 0.08 0.00 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.05 0.10 0.01 0.11 0.00 0.84 KN03-33 185.45 Semi Massive Sulfide 0.15 0.08 0 0.09 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.05 0.04 0.05 0.10 0.00 0.85 KN03-33 188.9 Semi Massive Sulfide 0.1 0.05 0.01 0.18 0.04 0.00 0.00 0.00 0.00 0.00 0.96 0.00 0.08 0.05 0.10 0.16 0.00 0.76 YES KN03-33 196.85 Semi Massive Sulfide 0.23 0.05 0.01 0.2 0.05 0.00 0.00 0.00 0.00 0.08 0.86 0.02 0.11 0.00 0.21 0.21 0.00 0.67 YES KN03-33 206.25 Semi Massive Sulfide 0.27 0.05 0 0.15 0.05 0.00 0.00 0.00 0.00 0.03 0.92 0.00 0.09 0.01 0.18 0.18 0.00 0.73 YES KN03-33 206.8 Semi Massive Sulfide 0.35 0.05 0.01 0.13 0.05 0.00 0.00 0.00 0.00 0.11 0.84 0.01 0.12 0.00 0.23 0.23 0.00 0.64 YES KN05-02 771.9 Semi Massive Sulfide 0.2 0.04 0 0.05 0.05 0.04 0.00 0.08 0.08 0.15 0.68 0.00 0.15 0.23 0.07 0.30 0.00 0.55 YES KN05-23 245.8 Semi Massive Sulfide 0.44 0.03 0 0.02 0.01 0.09 0.17 0.00 0.17 0.15 0.58 0.00 0.15 0.29 0.01 0.30 0.00 0.55 YES KN05-26 237.85 Semi Massive Sulfide 0.25 0.03 0 0.001 0.00 0.05 0.10 0.00 0.10 0.15 0.70 0.00 0.15 0.30 0.00 0.30 0.00 0.55 YES KN05-26 249.31 Semi Massive Sulfide 0.6 0.03 0 0 0.00 0.00 0.00 0.00 0.00 0.14 0.86 0.00 0.11 0.22 0.00 0.22 0.00 0.66 KN05-30 126.8 Semi Massive Sulfide 0.35 0.01 0 0.1 0.05 0.05 0.00 0.10 0.10 0.15 0.65 0.00 0.15 0.06 0.24 0.30 0.00 0.55 YES KN97-08B 592 Semi Massive Sulfide 0.07 0.01 0.01 0.09 0.05 0.07 0.00 0.14 0.14 0.15 0.59 0.00 0.15 0.00 0.30 0.30 0.00 0.55 YES KN98-56 297.8 Semi Massive Sulfide 0.25 0.05 0 0.03 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.00 0.06 0.07 0.06 0.12 0.00 0.81 Drillhole D . e p . t h Rock Type (m) Modal Abundances Observed During Petrography Po Pn Py Mgt Mineral Abundances Calculated using Minimized Sulfides version of the Mineral Prediction Filter Mgt Po Po(H) ^ Po Py Host Mineral Abundances Calculated using Maximized Sulfides version of the Mineral Prediction Filter Mgt Pn Po(H) ^ Po Py Host ORE? Semi KN98-56 317.35 Massive Sulfide Semi KN98-56 325.45 Massive Sulfide Semi KN03-33 208.2 Massive Sulfide 0.27 0.03 0.03 0.05 0.29 0.02 0 0.02 0.1 0.1 0 0.2 0.01 0.00 0.00 0.00 0.00 0.00 0.99 0.04 0.00 0.00 0.00 0.00 0.07 0.89 0.04 0.00 0.00 0.00 0.00 0.00 0.97 0.00 0.05 0.02 0.07 0.10 0.00 0.86 0.00 0.10 0.16 0.04 0.20 0.00 0.69 0.02 0.05 0.00 0.11 0.11 0.00 0.82 YES 

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