Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Trace element analysis of native gold by laser ablation ICP-MS : a case study in greenstone-hosted quartz-carbonate… Velasquez, Alejandro 2014

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
24-ubc_2014_spring_velasquez_alejandro.pdf.pdf [ 1.32MB ]
Metadata
JSON: 24-1.0074329.json
JSON-LD: 24-1.0074329-ld.json
RDF/XML (Pretty): 24-1.0074329-rdf.xml
RDF/JSON: 24-1.0074329-rdf.json
Turtle: 24-1.0074329-turtle.txt
N-Triples: 24-1.0074329-rdf-ntriples.txt
Original Record: 24-1.0074329-source.json
Full Text
24-1.0074329-fulltext.txt
Citation
24-1.0074329.ris

Full Text

     Trace element analysis of native gold by laser ablation ICP-MS: A case study in greenstone-hosted quartz-carbonate vein ore deposits, Timmins, Ontario   by  Alejandro Velasquez  BSc, National University of Colombia, Colombia 2006  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF  MASTER OF SCIENCE  in  THE COLLEGE OF GRADUATE STUDIES  (Environmental Sciences)   THE UNIVERSITY OF BRITISH COLUMBIA  (Okanagan)  April 2014  © Alejandro Velasquez, 2014    ii  Abstract  Native gold contains trace amounts of other elements and from the relative abundance of these a geochemical signature can be obtained. The trace element composition provides a “fingerprint” that is unique to the gold deposit it comes from. This fingerprint can be used to distinguish gold sources and potentially provide insight into the geochemical processes operating in the formation of Au deposits. Native gold grains were acquired from 3 gold ore deposits; Hollinger, McIntyre, and Aunor. These ore deposits are located near Timmins, Ontario, in the western end of the Porcupine gold camp, the south-western part of the Abitibi greenstone belt. Respectively, Scanning Electron Microscope analysis/Energy Dispersive Spectrometry (SEM/EDS) was used to determine major elements in gold grains. Ag concentrations from the SEM/EDS analyses were used as the internal standard for the laser ablation inductively coupled plasma mass spectrometry technique (LA-ICP-MS) that yielded trace element concentrations. A new reference material (AuRM2) served as the external standard for 22 elemental analytes for the LA-ICP-MS analyses. Trace elements in native Au associate according to Goldschmidt’s classification of elements demonstrating that element behavior in native Au is not random. Such element behavior suggests that samples from each deposit formed under similar geological conditions. Chalcophile and siderophile elements provide the most compelling fingerprints of the three ore deposits and they appear to be in solid solution in Au whereas lithophile elements are not very advantageous for distinguishing deposits and element concentrations appear to be controlled by micro inclusions such as tourmaline. The deposits show low Ag contents, which is consistent with mesothermal Au. Hollinger and McIntyre deposits have similar trace element abundances with high Ag, Pb, Bi, Sb and Pd and low Cu; however Cu concentrations in McIntyre are higher than in Hollinger. In contrast, Aunor has high Cu abundances and low Ag, Bi, Sb, Pb and Pd. Gold grain signatures reflect the chemical characteristics of the host rock superimposed on the chemical signature of the mineralizing fluid. The association of Pb-Bi-Cu bearing phases such as galena and chalcopyrite with gold supports hydrothermal fluids with high concentrations of these elements.    iii   Table of Contents  Abstract .............................................................................................................. ii Table of Contents ............................................................................................... iii List of Tables ....................................................................................................... v List of Figures ..................................................................................................... vi List of abbreviations ......................................................................................... vii Acknowledgments ........................................................................................... viii Dedication ......................................................................................................... ix Chapter 1.0 Introduction ..................................................................................... 1 Chapter 2.0 Literature Review ............................................................................ 3 2.1 Greenstone Hosted Quartz –Carbonate Vein ore deposits ................................................................ 3 2.2 Geological Characteristics of Greenstone-Hosted Quartz-Carbonate Vein Deposits. ........................ 4 2.2.1 Mineralogy ................................................................................................................................... 4 2.2.2 Host Rocks .................................................................................................................................... 4 2.2.3 Ore Chemistry .............................................................................................................................. 5 2.2.4 Alteration Mineralogy .................................................................................................................. 5 2.3 Distribution of Canadian Greenstone Hosted Quartz-Carbonate Vein Districts ................................ 5 2.4 Study Area ........................................................................................................................................... 6 2.4.1 Geological overview of the Porcupine Mining Camp ................................................................... 7 2.4.2 Gold mineralization in the Porcupine gold camp....................................................................... 10 2.5 Trace element composition of native gold and fingerprinting ore deposits .................................... 11 2.6 History of the study of trace elements in native gold ...................................................................... 12 Chapter 3.0 Sample Description and Petrography ............................................. 16 3.1 Sample Description ........................................................................................................................... 16 3.2 Petrographic analysis ........................................................................................................................ 16    iv  Chapter 4.0 Methods ........................................................................................ 20 4.1 Sample preparation .......................................................................................................................... 20 4.2 Scanning Electron Microscope (SEM/EDS) analysis .......................................................................... 20 4.3 Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analyses ................... 21 4.3.1 LA-ICP-MS Instrumentation and Operating Parameters ............................................................ 21 4.3.2 Gold Grain Ablation Strategy ..................................................................................................... 22 4.3.3 Reference Material, Analytes, and Internal Standards .............................................................. 23 4.3.4 Precision, accuracy and detection limits .................................................................................... 25 4.4 Data Processing by Glitter ................................................................................................................. 28 4.5 Multidimensional Scaling and Bivariate plots ................................................................................... 28 Chapter 5.0 Results ........................................................................................... 29 5.2 Gold analyses using chalcophile and lithophile elements ................................................................ 31 5.3 Bivariate plots and Au/Ag ratios ....................................................................................................... 31 5.4 Gold analyses from individual deposits. ........................................................................................... 33 5.5 Gold analyses from an individual sample. ........................................................................................ 36 Chapter 6.0 Discussion ...................................................................................... 37 6.1 Geochemical data comparison with previous studies. ..................................................................... 37 6.2 Chemical variation at a regional, ore deposit, and sample scale...................................................... 37 6.3 Patterns in element behaviour. ........................................................................................................ 38 6.4 Occurrence of trace elements in native gold. ................................................................................... 39 6.5 Variations in Au/Ag ratio. .................................................................................................................. 41 6.6 Chemical variations related to the local environment. .................................................................... 41 Chapter 7.0 Conclusions and Recommendations ............................................... 43 Bibliography ..................................................................................................... 47 Appendices ....................................................................................................... 53 Appendix A: SEM/EDX Results ................................................................................................................ 53 Appendix B: List of gold grains analyzed ................................................................................................. 57       v  List of Tables Table 2.1  Summary of mineralization features of Hollinger, McIntyre and Aunor                   Deposits ............................................................................................................. 14                                                                                                                                                                                                                             Table 3.1  Mossman’s descriptions for the ore samples .................................................. 17                                                                                                                  Table 3.2  Sample petrography ......................................................................................... 18   Table 4.1  Number of thin sections-grain mounts used for SEM and LA-ICPMS                   analyses, number of SEM-LA-ICP-MS analyses performed in slides ................. 21   Table 4.2  The operating parameters of the Laser ablation and ICP-MS instrument ....... 22   Table 4.3  Element concentration of reference materials ................................................ 24  Table 4.4  Trace element composition of gold ................................................................. 26   Table 5.1  Average of Au/Ag ratios and fineness for each ore deposit ............................ 33         vi  List of Figures  Figure 2.1  Inferred crustal levels of gold deposition showing the different types                      of lode gold deposits ......................................................................................... 4   Figure 2.2  Location of Canadian greenstone-hosted quartz-carbonate                     vein districts ...................................................................................................... 6   Figure 2.3  Generalised geological map of the Timmins area ............................................ 7   Figure 2.4  Stratigraphic column of the Porcupine gold camp ........................................... 9                Figure 3.1  Typical sulphide minerals and gold textures ................................................... 19   Figure 5.1  Elemental MDS plot produced with the data from the 64 analyses .............. 30   Figure 5.2  MDS plots labeled by ore and samples ........................................................... 30                         Figure 5.3  MDS plots using chalcophile and lithophile elements .................................... 31  Figure 5.4  Bivariate plots ................................................................................................. 32   Figure 5.5  Elemental-sample MDS plots from Hollinger ................................................. 34   Figure 5.6  Elemental-sample MDS plots from McIntyre ................................................. 35  Figure 5.7  Elemental-sample MDS plots from Aunor ...................................................... 35   Figure 5.8  Elemental MDS plot of Sample Au-27-1 ......................................................... 36      vii    List of abbreviations  Ppm= Parts per million Ppb= Parts per billion EMP= Electron microprobe EDS= Energy dispersive spectrometry  LA-ICP-MS= Laser ablation inductively coupled plasma mass spectrometer Ma= Million years RL= Reflected light PPL= Plane polarized light XPL= Cross polarized light MDS= Multi-dimensional scaling SEM= Scanning electron microscope MDLm =mean detection limit  Std devt= standard deviation         viii  Acknowledgments I would like to thank all of the people that made this project possible. I would like to thank Dr. David Mossman for providing the ore samples. Dr. John Greenough’s expertise, time, guidance, and infinite patience were fundamental throughout this process. I also thank Dr. Robert Kerrich who funded this project during the first year and whose insight and knowledge was invaluable. I offer my gratitude to the faculty and staff of the Earth and Environmental Sciences department who provided a great deal of support. I thank my committee members Dr. Yuan Chen and Dr. Kyle Larson for their continued support and insight. I also want to thank Dr. Paul Shipley for his valuable comments on my thesis.  Several other people were helpful and deserve mention as well: Dr.Bryan Fryer and his post-doc student Mohamed Shaheen for their knowledge and assistance on operating the “laser” and associated software, David Arkinstall for his wonderful job on the SEM/EDX analysis, and the graduate students Chantal Venturi and Mikkel Tetland for their valuable input. Finally, I would like to thank my mother for her moral and financial support, which without, this study would have not been possible.                  ix   Dedication  I dedicate this project to my mother, Margoth, my sisters, Cristina and Sandra.  They have always being there for me when I needed them the most.      1  Chapter 1.0 Introduction  Gold in nature is never 100% pure as it contains various other elements in major, minor and trace amounts. The concentrations of elements in gold can be very low (parts per billion) and, therefore, sensitive analytical techniques are required for analysis (Schlosser et al. 2009). Major (>1%) and minor elements (0.1-1%) (often Ag, Cu, and Hg) measured in gold have been detected using instruments such as the electron microprobe (EMP). In general, however instruments do not have the sensitivity or detection limits to measure trace element (<0.1%) concentrations. The laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) has the high sensitivity and low detection required to measure trace elements to less than parts per billion (e.g. Fryer et al. 1995). The analytical method of LA-ICP-MS for the determination of trace element composition in solid samples has been well established in the Earth sciences since its introduction 25 years ago (Gray 1985). Standard reference materials are essential in this analytical method for two major functions: calibration of the changing mass response of the ICP-MS and correction for the difference in ablation yield between the sample and calibration standard. According to Kogan et al. (1994) a major problem with solid sampling analysis is obtaining homogeneous standards that match the samples in chemical and physical characteristics, known as matrix matching. A matrix matched standard requires preparation and certification of element concentrations (Jackson et al. 2008). In this study, a certified gold standard (AuRM2) served as the external standard for 23 element analytes (Au, Ag, Al, As, Bi, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Si, Sn, Te, Ti, Zn).  The LA-ICP-MS’s ability to detect trace elements with high sensitivity and low detection limits makes it suitable for gold fingerprinting. It is the relative abundance, and ratios of various trace elements in individual gold grains that can provide a geochemical signature or “fingerprint”. This fingerprint can be used to distinguish gold sources (e.g. Outridge et al. 1998; Penney, G. 2001; Rasmussen et al. 2006; McInnes et al. 2008), track the origin of gold (e.g. Brown et al. 2003; Chapman and Mortensen, 2006), and potentially contribute to the understanding on how gold deposits form. A review of trace element composition of native gold from various deposits suggests that (1) a large number of trace elements have been    2  detected in native gold, (2) each deposit has its own suite of detectable elements, and (3) absolute concentrations of detected elements can vary considerably between both ore deposits and within the same deposit (e.g. McCandless et al. 1997; Penney, 2001). Gold from different occurrences should have different signatures as the geochemical conditions during the formation of each deposit may be dissimilar.   The native gold grains examined in this study are derived from greenstone hosted quartz-carbonate vein ore deposits (Hollinger, McIntyre, and Aunor). These ore deposits are located near Timmins, Ontario, the western end of the Porcupine gold camp. The Porcupine gold camp is one of the richest and most prolific gold mining camps in the world (Marmont and Corfu 1989; Robert and Paulsen 1997; Kerrich et al. 2000; Bateman et al. 2008). Having produced over 60 million ounces of gold since its discovery in 1909, the Porcupine gold camp’s mineralization is classified as structurally controlled quartz vein lode gold hosted within tholeitic mafic volcanic rocks, siliciclastic sedimentary rocks and quartz-feldspar porphyritic intrusions (Ferguson 1968; Burrows and Spooner 1986; Wood et al. 1986; Brisbin et al. 1997; Kerrich et al. 2000). In addition to the Hollinger, McIntyre and Aunor ore deposits, there are numerous other deposits along a > 35 strike length.       The primary focus of this study is to determine quantitative information on trace element concentrations in native Au to explore the relationships between trace elements and obtain geochemical signatures for the ore deposits. The thesis discusses the potential role of geological settings (host rock-associated minerals, etc.) to explain the distribution and abundances of trace elements in Au. This study differs somewhat from most trace-elements in native Au studies in that actual concentrations of trace elements are reported utilizing a new certified reference material (AuRM2) as an external standard for the LA-ICP-MS analyses.       3  Chapter 2.0 Literature Review    2.1 Greenstone Hosted Quartz –Carbonate Vein ore deposits Greenstone-hosted quartz-carbonate vein deposits are a subtype of lode gold deposits. They typically occur in deformed greenstone belts, especially those with variolitic tholeiitic basalts and ultramafic komatiitic flows intruded by intermediate to felsic porphyry intrusions, and sometimes with swarms of lamprophyre dykes (Gebre-Mariam et al. 1995). These types of deposits are most abundant and significant, in terms of total gold content, in Archean terranes. However, a significant number of world-class deposits are also found in Proterozoic and Paleozoic terranes (McCuaig et al. 1993). In Canada, they represent the main source of gold and are mainly located in the Archean greenstone belts of the Superior and Slave provinces. They also occur in the Paleozoic greenstone terranes of the Appalachian orogen and in the oceanic terranes of the Cordillera (Groves et al. 1998). Greenstone hosted quartz-carbonate vein ore deposits are distributed along major compressional to trans-tensional crustal-scale fault zones commonly marking convergent margins between major lithological boundaries, such as volcano-plutonic and sedimentary domains (Poulsen et al. 2000; Fig. 2.1). The greenstone-hosted quartz-carbonate vein deposits are structurally controlled, complex, epigenetic deposits characterized by simple to intricate networks of gold-bearing, laminated quartz-carbonate fault-fill veins (Poulsen et al. 2000). Veins are hosted by moderately to steeply dipping, compressional brittle-ductile shear zones and faults with locally associated shallow-dipping extensional veins and hydrothermal breccias. The deposits are hosted by greenschist to locally amphibolite-facies metamorphic rocks of dominantly mafic composition and formed at intermediate depth (5-10 km). The mineralization is syn- to late-deformation and typically post-peak greenschist -facies or syn-peak amphibolite-facies metamorphism. They tend to be associated with iron-carbonate alteration. Gold is largely confined to the quartz-carbonate vein network but may also be present in significant amounts within iron-rich sulphidized wall-rock selvages or within silicified and arsenopyrite-rich replacement zones (Dube and Gosselin, 2007).    4   Figure 2. 1.Inferred crustal levels of gold deposition showing the different types of lode gold deposits (Modified from Dube and Gosselin, 2007).    2.2 Geological Characteristics of Greenstone-Hosted Quartz-Carbonate Vein Deposits.      2.2.1 Mineralogy  The main gangue minerals in greenstone-hosted quartz-carbonate vein deposits are quartz and carbonate (calcite, dolomite, ankerite, and siderite), with variable amounts of white mica, chlorite, tourmaline, and locally sheelite. Sulphide minerals typically constitute less than 5 to 10% of the volume of the orebodies (Le Guen et al. 1992). The main ore minerals are native gold with, in decreasing amounts, pyrite, pyrrhotite, and chalcopyrite; there is no significant vertical mineral zoning. Arsenopyrite commonly represents the main sulphide in amphibolite- facies rocks and in deposits hosted by clastic sediments. Trace amounts of molybdenite and tellurides are also present in some deposits (Dube and Gosselin, 2007).      2.2.2 Host Rocks The veins in greenstone-hosted quartz-carbonate deposits have a wide variety of host rocks, but mafic and ultramafic volcanic rocks and competent iron-rich differentiated tholeiitic gabbroic and granitoid intrusions are common hosts. However, there are commonly district-specific lithological associations, acting as chemical and/or structural traps for the mineralizing    5  fluids. For example, veins occur in tholeiitic basalts within the Tisdale Assemblage in Timmins (Hodgson and MacGeehan, 1982; Brisbin, 1997).     2.2.3 Ore Chemistry The geochemical signature of greenstone-hosted quartz-carbonate vein ore bodies is controlled by the concentrations of Au, Ag, As, W, B, Sb, Te, and Mo, with background or only slightly anomalous concentrations of base metals (Cu, Pb, and Zn). The Au/Ag ratio in native gold typically varies from 5 to 10. Contrary to epithermal deposits, there is no vertical metal zoning (Groves et al. 1998; Dube and Gosselin, 2007).     2.2.4 Alteration Mineralogy At a district scale, greenstone-hosted quartz-carbonate vein deposits are associated with large-scale carbonate alteration commonly distributed along major fault zones and associated subsidiary structures. At a deposit scale, the nature, distribution, and intensity of the wall rock alteration is controlled mainly by the composition and competence of the host rocks and their metamorphic grade (Groves et al. 1998). Typically, the proximal alteration haloes are zoned and characterized, in rocks at greenschist facies, by iron carbonatization and sericitization, with sulphidation of the immediate vein selvages (mainly pyrite, less commonly arsenopyrite) (Goldfarb et al. 2001).    2.3 Distribution of Canadian Greenstone Hosted Quartz-Carbonate Vein Districts The most productive Canadian metallogenic districts for greenstone-hosted quartz-carbonate vein deposits occur in Late Archean greenstone belts of the Superior, Churchill, and Slave provinces (See Fig. 2.2). The Abitibi greenstone belt contains the majority of the productive districts, including the very large Timmins, Kirkland Lake, Larder Lake, Rouyn-Noranda, and Val d’ Or districts (Joyce 2006). Other younger greenstone belts of the Appalachian and Cordillera orogens are also favourable terranes for quartz-carbonate vein-type gold deposits (Dube et al. 2007).     6   Figure 2.2.  Location of Canadian greenstone-hosted quartz-carbonate vein districts within major lithotectonic provinces (modified from Dube and Gosselin, 2007).    2.4 Study Area The McIntyre, Hollinger, and Aunor mines are located near Timmins, Ontario, in the western end of the Porcupine gold camp. The Porcupine gold camp is located in the south-western part of the Abitibi greenstone belt, an elongated belt of metamorphosed volcanic, sedimentary and intrusive rocks of Archean age (see Fig. 2.3).        7    Figure 2.3. Generalised geological map of the Timmins area, showing major gold mines and the mines studied (Hollinger, McIntyre, and Aunor). (Modified from Fryer et al. 1978).  2.4.1 Geological overview of the Porcupine Mining Camp The Porcupine mining camp is the most productive lode district in North America and also lies within the world’s largest and most prolific gold-producing greenstone belt, the Abitibi a subdivision of the Archean Superior Province (Gray et al. 2001). The gold deposits of the    8  Porcupine camp are spatially related to the Destor-Porcupine fault, a major structural feature which can be traced eastward to the Quebec border (Smith et al. 1984). In the Timmins-Porcupine gold camp, historic plus modern gold production and resources total 2150 metric tons (Gosselin and Dube, 2005). In addition to the Hollinger, McIntyre and Aunor there are numerous other deposits along a > 35 Km strike length.  The district has been of economic and academic interest since its discovery in 1909, and hundreds of papers discuss various aspects of its geology. Excellent overviews of the district’s geology are comprehensive reports of Ferguson (1968) and Pyke (1982). Other important publications include; discussions of structural and geologic settings by Dunbar (1948), Davies (1976) and Brisbin (1977); stratigraphic descriptions by Lorsong (1975), Ayer et al. (1998) and Thurston et al. (2008) ; petrologic, geochemical, and alteration studies by Davies et al. (1990) and Duff (1982); fluid inclusion data of Smith et al. (1984).  Pyke (1980) divided the metavolcanic rocks of the Porcupine camp into the Deloro and Tisdale Groups, each representing a compositional cycle of komatiitic to tholeiitic to calc-alkaline volcanism. Fig. 2.4 shows the stratigraphic column of the Porcupine gold camp. Major accumulations of clastic sedimentary rocks form the Porcupine Group (Lorsong 1975), the lower part of which is interpreted to be a facies equivalent of the Tisdale Group. Nunes and Pyke (1981) dated a tuff from the upper portion of the Deloro Group and a rhyolite from the top of the Tisdale Group at 2725 ± 2 Ma and 2703 ± 3 Ma., respectively. The Deloro assemblage is overlain by the volcanic Tisdale Assemblage (2710-2703 Ma) which hosts the majority of gold deposits in the Porcupine camp. The Tisdale Assemblage volcanic rocks are intruded by numerous porphyritic felsic bodies (2687-2691 Ma) (Ayer et al. 2002). Further intrusive magmatism occurred at 2672 ± 1.1 Ma with the emplacement of late albitite dykes; coarse grained rocks consisting essentially of albite (Ayer et al. 2005). These albitite dykes represent the last magmatic event prior to gold mineralization, are volumetrically minor, and are only present locally within the Porcupine gold camp.     9   Figure 2.4. Stratigraphic column of the Porcupine gold camp, Abitibi greenstone belt. (Modified from Pyke 1982; Ayer et al. 2002)10     2.4.2 Gold mineralization in the Porcupine gold camp  The Abitibi subprovince hosts diverse styles of gold deposits showing various chronological relationships with deformation, formed at different times and at different crustal levels along the Porcupine-Destor zone (Poulsen et al. 2000). Features common to such deposits (e.g. Hutchinson, 1993; Robert and Paulsen, 1997; Gray and Hutchinson, 2001) include: Archean age of host rocks and mineralization; host greenstone terranes that include ultramafic to felsic volcanic rocks, their subvolcanic and/or plutonic equivalents, and clastic and chemical sedimentary rocks; association with major structural zones; great vertical extent (1-2 km) of mineralization, commonly lacking appreciable mineralogical and/or geochemical zoning; associated carbonate alteration at both deposit and district scale; non-specificity of host rocks within the greenstone terrane; common spatial association with felsic intrusive rocks; and common occurrence at or near a volcanic-sedimentary rock interface. Gold mineralization at the McIntyre and Hollinger mines is hosted by metamorphosed, pillowed, and variolitic mafic lavas and felsic flows and pyroclastic rocks of the Tisdale group (Ferguson et al. 1968; Pyke, 1980). Tabular bodies of porphyritic quartz-albite-sericite schist occur within the flows and are interpreted to be altered felsic tuffs erupted from high level intrusions with associated volcanic domes. One such unit, the Pearl Lake Porphyry, crops out on the McIntyre property and hosts a disseminated Cu-Au-Mo deposit (Davies and Lutha, 1978). The copper deposit displays some features characteristic of porphyry copper occurrences, such as volcanic host rock, and Cu-Mo sulphides (Davies, 1976). Gold mineralization at the McIntyre and Hollinger mines mainly consists of quartz-ankerite veins, stockworks, and sinuous lodes and stringers which crosscut the wall rocks (Smith et al. 1984). Native gold occurs along fractures in vein quartz and as blebs on the surface of the pyrite cubes and enclosed entirely within them. The gold with very minor pyrrhotite, galena, sphalerite, various tellurides, and abundant quartz, was precipitated late in the sequence of mineralization, following the deposition of quartz-ankerite-tourmaline and quartz-pyrite-arsenopyrite assemblages (Keys 1940). The Cu-Au-Mo mineralization is crosscut by narrow ankerite-quartz veins that are in turn crosscut by quartz-ankerite-albite-scheelite-tourmaline-sulphide-telluride-native gold veins (Wood et al. 1986). Bateman et al. (2008) suggest that disseminated copper ores within the porphyry at McIntyre    11  and the gold-bearing quartz veins in the surrounding volcanic rocks are genetically related to each other. The Aunor deposit is contained within a series of interbedded-pillowed, massive and tuffaceous basalts (andesite in mine terminology) sandwiched between talc-chlorite schist rocks of the Hersey Lake Formation. Hersey Lake Formation is the lower-most unit of the Tisdale Group which disconformably overlies the Deloro Assemblage (Bateman et al. 2008). The Aunor mine has quartz-ankerite-pyrite-gold veins (5 mm to 5 m wide) that are crosscut and offset by younger quartz-tourmaline-pyrite-gold veins. Table 2.1 summarizes the geological features of the Hollinger, McIntyre and Aunor ore deposits.    2.5 Trace element composition of native gold and fingerprinting ore deposits There are a wide variety of types of gold mineralization, reflecting differences in geological setting, the chemistry of ore fluids, and nature of reactions with wall rocks. Characterization and classification of ore deposits has long been based on assessment of the geological environment of formation as inferred from structures, mineralogy and chemical data (Chapman et al. 2002). More recently, genetic models of major deposit types have been formulated by combining descriptive information with physics and chemistry information on mineralization processes from experimental and theoretical work.  Hedenquist (1996) suggests that chemical variations, both in the environment of ore fluid generation and ore precipitation, result in a considerable array in the mineralogy of gold-bearing ores. This manifests itself both in the composition of the native gold alloy and the associated minerals. This variation may also be seen in comparisons of gold deposits of the same type. In most types of mineralization, such as hydrothermal veins, the gold grain signature reflects the chemical characteristics of the host rock superimposed on the chemical signature of the mineralizing fluid (Hedenquist et al. 1996; Chapman et al. 2002).  Commonly, minerals which co-exist with native gold in the source mineralization also occur as microscopic inclusions within the gold (Chapman et al. 2002). The record of the mineral inclusion assemblages helps to generate classifications of gold grain chemistry which combine this information with that of the gold alloy composition. Mineral inclusions are of two    12  types: opaque minerals, such as sulphides and sulphoarsenides, and silicate minerals, most commonly quartz and carbonates. In the case of greenstone hosted quartz carbonate vein deposits the consistency in the depositional environment of mesothermal gold described by Morrison et al. (1991) also results in relatively simple inclusion assemblages, typically dominated by sulphides and arsenides. In general, the opaque mineral assemblage is more useful in characterizing the type of source of mineralization. Characterization of the silicate inclusion suite is rarely important in the study of mesothermal gold mineralization (Chapman et al. 2006). The opaque microinclusions are sometimes difficult to observe because of their small size (<5um to 0.5um) which are generally represented in chemical analysis as metals dissolved in the Au.    2.6 History of the study of trace elements in native gold The influence of variation in the concentration of alloying elements on the color of native gold was apparent even in antiquity, but the quantitative study of the chemical composition of individual gold grains only became possible with the development of electron microprobe analysis in the 1960s. Several studies of placer gold grains using this technique (e.g., Stumpfl and Clark, 1965; Desborough, 1970) demonstrated that the Ag content of gold can vary considerably within individual grains and also between grains collected from different localities. Subsequently there have been many studies of Ag, Cu and Hg concentrations in gold using the electron microprobe. Morrison et al. (1991) provided comprehensive data outlining differences in gold fineness between major classes of gold mineralization. There are broad compositional differences between deposit types, e.g., gold from epithermal deposits is usually much richer in Ag than gold from Archean and slate belt vein deposits. Antweiler and Campbell (1977, 1982) augmented electron microprobe analyses with semiquantitative optical emission spectroscopy analyses to extend the range of elements considered. They detected differences in such elements as As, Bi, Ni, and Sb between gold from different deposits but were not able to establish whether these elements occurred in solid solution or in mineral inclusions.  More recently the technique of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has been utilized to extend the range of elements detectable within    13  gold (Outridge et al. 1998; Penny, G.2001; Rasmusen et al. 2006; McInnes et al. 2008). The potential use of LA-ICP-MS for the determination of trace, and ultra-trace element concentrations in gold has been apparent since the instrument’s introduction 25 years ago (Gray 1985). Its ability to detect trace elements at low concentrations makes it suitable for gold fingerprinting.          14  Table 2.1. Summary of geological and mineralization features of the three deposits studied. Ore deposit Hollinger McIntyre Aunor Deposit Classification Mesothermal Mesothermal Mesothermal Deposit characteristic Vein-strata bound Vein-strata bound Vein-strata bound Tectonic/Stratigraphic assemblage Tisdale Group Tisdale Group Hersey Lake formation (Tisdale Group)  Geological age The ages of the tops of the Deloro and Tisdale Groups are 2725 ± 2 Ma and 2703 ± 2 Ma respectively (Nunes and Pyke, 1980). The ages of the tops of the Deloro and Tisdale Groups are 2725 ± 2 Ma and 2703 ± 2 Ma respectively (Nunes and Pyke, 1980).  NeoArchean  Host Rocks Ore deposit hosted by metamorphosed, pillowed, and variolitic mafic lavas felsic flows and pyroclastic rocks, locally derived clastic and chemical sedimentary rocks. Mineralization is hosted by metamorphosed, pillowed, and variolitic mafic lavas and felsic flows and pyroclastic rocks. Deposit interbedded with pillowed, massive and tuffaceous basalts sandwiched between units of talc-chlorite schist.    Description of Mineralization Most gold occurs in a quartz-ankerite-pyrite type of ore body and was introduced later than the major period of quartz mineralization. Vein gold appears genetically related to a pale green sericite and was localized around and in inclusions of such minerals as pyrite, sheelite, arsenopyrite and ankerite. The deposit includes the Cu-Au-Ag-Mo orebody and main stage quartz-carbonate-Au veins. Several stages of sulphide mineralization have been described. Mineralization occurs as a series of lenses over 1200 vertical meters, subparallel to east-plunging lineations. The ore occurs in a series of parallel and branching veins which do not extend into the hanging-wall or footwall talc-chlorite schists. Veins strike about parallel to the ore zone, though they tend to traverse east to west from the hanging-wall to the footwall. The veins average 1.0 m wide and dip about 50 degrees N. The height of the veins, measured along the dip is about 106 m.      15  Table 2.1. Summary of geological and mineralization features of the three deposits studied.  Ore deposit Hollinger McIntyre Aunor  Alteration style Wall-rock alteration consists of carbonatization and sericitization. Closer to mineralization, the rocks are altered sequentially to quartz-albite-chlorite-calcite-epidote and quartz-albite-chlorite-ankerite assemblages. Wall-rock alteration consists of carbonatization and sericitization. The wallrock to the veins is weakly sheared, brecciated, and altered by carbonate, brown tourmaline, scheelite, pyrite and minor chalcopyrite. Mineralogy Native gold, pyrite, pyrrhotite, galena, sphalerite, various tellurides, and abundant quartz. Native gold, galena, sphalerite, tellurides, chalcopyrite, pyrite, pyrrhotite and abundant quartz-carbonate. Native gold, pyrite, chalcopyrite, tourmaline, carbonate, sheelite. Other types of  mineralization Associated porphyry bodies, located principally at contacts with the sediments or greenstones. Disseminated Cu-Au-Mo deposit in Pearl Lake Porphyry Formation. Other types of mineralization are not reported in the literature. Fluid inclusions Mineralization occurred at temperatures of 400°C to 470°C , at pressures of 1,300 to 2,900 bars, and at depths of 5 to 12 Km. Same fluid inclusion results were obtained for the McIntyre ore deposit as for Hollinger. No fluid inclusion studies were found in the literature for the Aunor ore deposit.   References Keys (1940); Davies (1976); Fryer et al. (1978); Smith et al. (1984); Cameron and Hattori (1987); Bell et al. (1989);  Gray et al. (2001); Bateman et al. (2008); McDonald (2010). Keys (1940); Davies (1976); Fryer et al. (1978); Smith et al. (1984); Cameron and Hattori (1987); Bell et al. (1989); Gray et al. (2001); Bateman et al. (2008); McDonald (2010). Smith et al. 1984; Bateman et al. 2008.         16  Chapter 3.0 Sample Description and Petrography    3.1 Sample Description  Native gold grains from 8 ore samples were chemically analyzed by Energy Dispersive Spectrometry (EDS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Samples were donated by David Mossman and his brief descriptions are summarized in Table 3.1. Three specimens come from the Hollinger ore deposit, two from McIntyre and three are from the Aunor deposit.  A total of 8 grain mount slides were prepared from the hand specimens. A total of 4 standard 22 x 44mm petrographic thin sections were acquired from representative hand specimens (1 slide comes from the Hollinger mine, 2 slides from the McIntyre mine and one from the Aunor mine) for petrographic analyses of minerals associated with gold. The number of gold grains available in grain mounts and thin sections from the three ore deposits varies from one ore deposit to another.    3.2 Petrographic analysis  Petrographic analysis was completed to identify minerals and help determine their relationships with native gold grains in order to select the gold grains for the EDS and LA-ICP-MS analysis. The polished thin sections were examined using a petrographic microscope under plane polarized light (PPL), cross polarized light (XPL), and reflected light (RL). Table 3.2 summarizes the sample petrography and Fig. 3.1 shows typical sulphide minerals, alteration minerals and gold textures.  The four petrographic thin sections come from quartz-carbonate vein samples. Major phases include quartz and carbonates with accessory tourmaline and sericite. Alteration minerals include; sericite and chlorite. Some of the samples have only sericite as an alteration mineral (e.g Figs. 3.1a-3.1b) and sample Au6-1 has both chlorite and sericite occurring together.  The chlorite-sericite alteration is patchy, occurring as veinlets that crosscut quart-carbonate veins. Some veinlets are mineralized with gold and sulphides. The major opaque phases are pyrite, magnetite, chalcopyrite, galena, sphalerite and arsenopyrite with pyrite the dominant sulphide. Pyrite is disseminated throughout in fine-grained matrix and contains gold inclusions. Galena and arsenopyrite are disseminated in quartz-carbonate veinlets. Gold is hosted mainly in carbonate-chlorite microveinlets and as a replacement in carbonates; moreover, it can also replace pyrite (Fig. 3.1c).      17  Table 3.1. Brief notes on samples by D. Mossman Sample Mine Description Au4-16 Hollinger Grey glassy quartz in porphyry with pyrite and visible gold- 5300’ level Au4-18 Hollinger Quartz with free gold and chrome mica in fracture- 5300’ level Au4-19 Hollinger Quartz banded mineralization, free gold with galena- 5300’ level Au6-1 McIntyre # 25 vein ore-quartz with tourmaline, sericite, carbonates, pyrite and visible gold- 3178- stope #2 Au6-13 McIntyre # 22 vein ore-quartz tourmaline, pyrite, gold- 4370- stope#2 Au27-1 Aunor Gold ore (display piece). Quartz vein material with wall rock inclusions. Much visible gold, some brown tourmaline and ankerite Au27-2 Aunor Gold ore. Quartz vein material. Coarse visible gold. Much brown tourmaline, some ankerite and fine disseminated sulphides. 2900 level-29-29S stope Au27-3 Aunor Gold ore. Quartz vein material. Coarse visible gold. Much brown tourmaline, some ankerite and fine disseminated           18  Table 3.2. Summary of sample petrography Sample Major Phases Opaque Minerals Gangue Minerals Alteration Comments  Au4-18 Carbonates Quartz  Pyrite, magnetite, pyrrhotite, galena Tourmaline, Sericite, chrome mica,   Sericite Gold is mainly hosted in quartz micro-veinlets. Pyrite replaces carbonate grains. Chalcopyrite is associated with gold. Carbonates exhibit twinning.  Au6-1 Carbonates Quartz Pyrite, magnetite, sphalerite Chlorite, sericite, brown tourmaline  Chlorite, sericite Pyrite, galena and gold are disseminated in chlorite-sericite micro-veinlets. Gold also occurs disseminated in quartz. There are a few pyrite grains replaced by gold in micro-fractures. Course gold grain (approx. 1000um) hosted in carbonate crystals.  Au6-13 Carbonates Quartz Pyrite, magnetite, chalcopyrite Brown tourmaline, sericite Sericite Course brown tourmaline. Gold occurs filling fractures in pyrite grains. Magnetite disseminated throughout fine quartz carbonate matrix. Chlorite is associated with sericite in microveinlets.    Au27-1 Carbonates Quartz Chalcopyrite, pyrite, magnetite, arsenopyrite Tourmaline, sericite  Sericite Magnetite is disseminated in quartz-carbonate fine grained matrix. Arsenopyrite is associated with gold. Pale pyrite crystals associated with gold.        19   Figure 3.1. a) Photograph of Au6-1 (PPL) showing opaque minerals in sericite alteration. b) Photograph of sample Au6-1 (PPL) showing sericite alteration on carbonates. c) Gold inclusions in pyrite (Py). Gold disseminated in carbonates (RL). d) Gold grains hosted in carbonates (RL). e) Gold hosted in chlorite veinlets (RL). f) Gold disseminated in quartz fine matrix (RL). g)  High resolution image (back-scatter mode) of Au6-1 displaying microveinlets of gold hosted in quartz-carbonate fine matrix. h) Photograph of Au4-18 showing sulphides associated with gold (RL). i) Laser track on gold grain. Note, the width of the laser track is approximately 25 um and the length 50 um.    20  Chapter 4.0 Methods    4.1 Sample preparation Visible gold grains were removed from the ore hand specimens using a circulating pointed diamond bit. The gold grains were set in epoxy as an array and then polished flat. In preparation for SEM and LA-ICP-MS analysis gold grains were circled and photographed on both the thin sections and grain mounts. Photographs were taken of each circled spot in plane polarized light (ppl), under crossed polars (xpl) and using reflected light (rl) for reference during analysis. Prior to the SEM analyses grain mount slides and petrographic thin sections were carbon coated at C.F. Mineral Research Ltd (CFM) in Kelowna, BC. Thickness of the coating is ~200Å. Table 4.1 summarises the number of thin sections, grain mounts, and SEM-LA-ICP-MS analyses performed for each ore deposit.   4.2 Scanning Electron Microscope (SEM/EDS) analysis A Tescan Mira3 XMU Scanning Electron Microscope (SEM) with an Oxford Aztec X-max Energy Dispersive Spectrometry (EDS) system and 80 mm2 silicon drift detector were used for the major element analysis of gold grains. Processing of the SEM data was completed using Oxford Aztec software. The SEM is part of the Fipke lab for trace element research (FILTER) located in the Fipke building, at UBC Okanagan in Kelowna, B.C. A total of 150 SEM/EDS analyses were carried out on thin sections and grain mounts (see Table 4.1). Only three major elements were detected in the SEM/EDS analyses (Au, Ag, and Fe) and Fe was rarely detected (e.g. Au6-1, Au27-1). Over half of the gold grains were analyzed more than once to obtain representative average compositions. SEM/EDX Au analyses appear in Appendix A.  SEM/EDS analysis was carried out in preparation for LA-ICP-MS analyses. LA-ICP-MS requires an internal standard to correct for differing ablation yields between the samples (Fryer et al. 1995). A naturally occurring internal standard must be used for the analysis of solid materials in their natural state. When using an internal standard, a major element is chosen and its concentration must be determined first from independent analysis (e.g. SEM) (McCandless et al. 1997). In this study, Ag concentrations were used as an internal standard.        21  Table 4.1. Number of thin sections-grain mounts used for SEM and LA-ICPMS analyses and number of SEM-LA-ICP-MS analyses acquired. Sample Mine Thin sections Grain mounts Thin Sections Grain mounts LA-ICP-MS analyses     SEM analyses  Au4-16 Hollinger  1  3 2 Au4-18 Hollinger 1 1 15 9 9 Au4-19 Hollinger  1  10 8 Au6-1 McIntyre 1 1 46 14 14 Au6-13 McIntyre 1 1 14 4 4 Au27-1 Aunor 1 1 8 8 8 Au27-2 Aunor  1  7 7 Au27-3 Aunor  1  12 12 Totals   4 8 83 67 64     4.3 Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analyses Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of Au were conducted at the Great Lakes Institute for Environmental Research (GLIER) at the University of Windsor in Windsor, ON. A total of 64 LA-ICPM-MS analyses were carried out (19 Hollinger, 18 McIntyre and 27 Aunor). All analyses were completed in one session in March 2013. Attempts to analyze gold grains in the thin sections were made but results were compromised by burn-through.      4.3.1 LA-ICP-MS Instrumentation and Operating Parameters GLIER’s LA-ICP-MS instrument is a non-homogenised, femtosecond, 266 nm Nd-doped Y-Al garnet (Nd: YAG) laser connected to a Thermo-Elemental X-7 ICP-MS. The laser and ICP-MS operating parameters are listed in Table 4.2. Details of the laser ablation, ICPMS system and operating conditions are as Shaheen et al. (2013).     22    Table 4.2. Operating parameters of the Laser and ICP-MS instrument used in the study. Parameter Setting Laser   Laser spot size 20-25 um Laser frequency (energy) 100 Hz Pinhole diameter 2.5 mm Ablation track traverse length 300 um Ablation width 20-25 um Laser scan speed 5 um/s ICPMS   Manufacture Thermoelectron Model X7-II Coolant gas flow rate 13 L/min Auxiliary gas flow rate 1 L/min Nebulizer gas 1.05 L/min ICPMS forward RF power 1300 W      4.3.2 Gold Grain Ablation Strategy The gold grains were ablated by rastoring along a line rather than using stationary spot drilling; this maximized instrument sensitivity (Mank and Mason 1999). Gold grains were traversed with the laser at a rate of 5 um/s with a maximum 60 s acquisition time. Each data acquisition time was preceded by a 60 s gas blank to determine background. The laser spot size was between 20-25 um with an average ablation track traverse of 300 um (speed of 5 um/s* 60    23  s acquisition). Gold was analyzed in high resolution mode to lower detector counts. The other elements were analyzed in standard resolution mode.      4.3.3 Reference Material, Analytes, and Internal Standards Two reference materials were used in the experiment; AuRM2 and NIST610. AuRM2 served as the external standard for 22 elemental analytes (Ag, Al, As, Bi, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Si, Sn, Te, Ti, Zn). AuRM2 has been tested for homogeneity at a macroscopic level (Murray 2009). The element concentrations list of each reference material is summarized in Table 4.3. The elemental concentrations of the NIST610 glass and AuRM2 were obtained from Jochum et al. (2007) and Murray (2009) respectively. The NIST610 glass and AuRM2 were ablated using the same parameters as for the gold grain analyses. A total of 5 replicate analyses of AuRM2 and NIST610 glass were performed per run. The run sequence was; two AuRM2 analyses followed by one NIST610 before the gold analyses and two AuRM2 afterwards. The analyte list consisted of 26 isotopes (197Au, 107Ag, 109Ag, 27Al, 75As, 209Bi, 43Ca, 52Cr, 63Cu, 56Fe, 57Fe, 25Mg, 55Mn, 60Ni, 62Ni, 208Pb, 105Pd, 195Pt, 103Rh, 121Sb, 78Se, 29Si, 118Sn, 125Te, 46Ti, 66Zn.) for all the Au analyses. Silver (109Ag) was used as the internal standard. 109Ag was chosen based on its better accuracy and precision over 107Ag. Also, the 109Ag standard deviation on the AuRM2 analyses was 5.6 ppm; almost three times lower than the 107Ag which was 16.0 ppm. An internal standard was used to account for the differing ablation yield between the sample and reference material (Mokgalaka and Gardea-Torresdey 2006).                24    Table 4.3. Element concentration of reference materials.        Reference material AuRM2 NIST610Reference  Murray (2009) Jochum et al.,(2007)Element ppm ppmAg 99.6 251Al 28.3 10320.2As 47.1 325Bi 9.7 384Ca 28 81475Cr 27.7 408Cu 31.6 441Fe 30.1 458Mg 9.9 432Mn 28.2 444Ni 29.2 458.7Pb 28.9 426Pd 29.2 1.21Pt 30.2 3.12Rh 39.6 1.29Sb 11.3 396Se 37.4 138Si 28 325798.7Sn 29.4 430Te 12 302Ti 31.6 452Zn 31.4 460Au 99321.6 23.6   25     4.3.4 Precision, accuracy and detection limits The detection limits and precision of LA-ICP-MS analyses are functions of a number of variables with the mass of material ablated (pit volume) and the counting time per element during ablation being the most important (Jackson et al. 1992). The size of the ablation pit is controlled by ablation time, laser intensity, and mineral type. Higher count rates and improved detection limits and precision are generated by larger pit sizes. Longer ablation times can also improve detection limits and precision, however, the spatial resolution of the analysis is lowered. The counting time per element is a function of the number of elements that are determined during an analysis. Detection limits and precision are inversely proportional to the number of elements determined, (i.e., the greater the number of elements analyzed the lower the detection and precision) (Longerich et al. 1993). Table 4.4 summarizes the gold analyte concentrations obtained by LA-ICP-MS along with estimates of accuracy, precision, and detection limits. Appendix B gives analysis numbers and their corresponding ore sample plus deposit.  A total of 48 analyses were carried out on the AuRM2 standard throughout all the gold analyses. Two replicate analyses were taken before ablating the unknown gold grains and two after each run. Standard deviation, precision, accuracy and detection limits were determined for all the elements in the analyte list. The original analyte list has 22 elements, three of which have two isotopes: 56Fe, 57Fe; 60Ni, 62Ni; and 107Ag, 109Ag. 57Fe, 60Ni and 109Ag were chosen based on their isotopes’ precision and accuracy. 78Se was generally (90% of the analyses) below detection limits and is not reported in data tables.  Precision values (see Table 4.4) of most of the elements analyzed are better than 10% and typical of LA-ICP-MS trace element analyses. Au is the most precise element followed by Pt, the second most precise element. Si has the worst precision value followed by Te, Ca and Al. Generally, lithophile elements appear to have poor precision values. The most accurate elements are Au, Ag and Pb. Accuracy values for the rest of the elements vary from 0.5 to 1.5%. Trace element composition of the 64 gold analyses is shown in Table 4.4. The number of analyses for individual samples reflects the availability of grains large enough for analysis (e.g. sample H4-16 only has two analyses). Blanks in the dataset correspond to the analyses that fell below the detection limits.  Au, Ag, Cu, Al, Sb were detected in all the analyses. In contrast, almost half of the analyses for Pd and Ni fell below the detection limits. Arsenic was detected in 60% of analyses. 18 elements out of 22 were detected in 80% of the analyses.             26  Table 4.4. Trace element composition of gold. Notes: 1) Analysis gives abbreviated spectrum/analysis number preceded by ore deposit symbol (H=Hollinger, M=McIntyre, A=Aunor). 2) All elements in ppm.3) Numbers before the elements (top row) represent the isotope selected for detection. 4) Blanks cells correspond to values below detection limits. At the bottom of table values for MDLm, Average Standard deviation, Precision, and Accuracy are calculated from 48 replicate analyses of AuRM2. 5) MDLm =mean detection limit. 6) Std devt= standard deviation. 7) Precision (Precision= (Std/mean)*100). 8) Accuracy is in % [(absolute value (mean Std. –Lab Std.))/Lab Std.] x 100%.    Analysis25Mg27Al29Si43Ca46Ti52Cr55Mn57Fe60Ni63Cu66Zn75As103Rh105Pd109Ag118Sn121Sb125Te195Pt197Au208Pb209BiH4-16-1 19.8 361 153 3.57 0.12 0.082 446 0.24 129 0.271 0.006 138196 0.051 1.61 0.263 0.019 900987 0.38 1.39H4-16-2 46.3 12.8 525 79.0 0.8 0.196 48.6 0.2 95.4 4.71 1.96 0.017 0.076 152520 0.095 0.815 2.78 895788 1.57 11.8H4-18-1 47.5 17.0 22.3 80.0 1.69 0.36 2.6 80.1 3.93 30.2 2.56 0.23 0.003 0.076 210302 0.037 0.483 0.497 0.022 843386 1.13 0.64H4-18-2 25.5 1.5 4.57 6.91 25.3 0.141 0.081 205653 0.025 0.19 0.024 845693H4-18-3 426 250 101 756 1.73 10.1 22.2 732 4.92 20.2 0.276 1.23 0.005 0.046 211640 0.041 0.238 1.17 842493 5.49 1.26H4-18-4 19.6 298 96.4 18.6 1.32 14.5 0.317 206 137 21.7 0.192 0.13 0.002 204849 0.042 0.211 0.313 0.022 842887 1.95 0.433H4-18-5 161 220 1408 98.5 22.5 1.47 509 11 19.3 0.284 1.09 0.003 0.044 222641 0.099 0.212 0.92 843386 5.03 0.340H4-18-6 189 354 239 38.3 6.7 25.9 0.761 506 8.49 23.1 0.45 0.96 220103 0.083 0.236 0.4 0.020 845693 2.93 0.424H4-18-7 359 727 404 61.8 1.21 46.6 11.3 1473 402 19.7 0.277 169 0.007 0.098 238139 0.084 0.803 2.75 0.021 842493 9.83 2.20H4-18-8 90.8 107 63.2 10.2 0.31 4.52 0.215 195 1.37 27.8 0.374 0.004 229222 0.021 0.236 0.313 0.016 844693 0.025 0.26H4-18-9 15.1 19.5 16 15.4 1.08 1.27 0.124 45.8 1.18 28.3 0.122 0.004 0.082 234361 0.014 0.278 0.607 0.019 838188 0.867 0.30H4-19-1 0.43 0.365 1.99 0.044 0.12 32.5 0.108 0.004 0.099 228157 0.027 0.438 0.307 0.010 845164 120 4.66H4-19-2 1.06 6.6 1.14 0.019 56.9 0.104 0.024 0.103 212319 0.016 0.511 0.656 0.013 839994 1067 3.06H4-19-3 0.66 2.18 0.80 0.048 0.44 84.3 0.088 0.003 0.037 211642 0.031 0.291 0.103 0.016 842829 4.02 0.092H4-19-4 1.03 8.27 0.39 0.08 103 0.109 0.013 203846 0.035 0.545 0.28 0.015 849191 667 10.9H4-19-5 7.77 1.22 34.3 14.2 1.63 1.006 72.1 11.3 26.2 0.117 0.006 198460 0.055 1.122 5.66 0.012 840388 39.0 5.87H4-19-6 1.52 1.47 31.2 8.35 2.87 0.15 0.079 4.88 63.4 0.109 0.007 0.106 212441 0.026 0.615 0.75 0.018 845491 40.0 4.47H4-19-7 0.34 1.29 5.33 6.37 1.48 0.06 40.8 0.104 0.006 0.125 209413 0.056 0.851 0.101 0.017 844790 2.29 0.278H4-19-8 1.54 4.6 2.46 121 0.099 0.008 0.041 198107 0.014 1.5 0.343 0.026 853496 2.53 0.292M6-1-1 112 89.3 375 378 0.45 1.79 155 0.48 50.3 0.6 4.6 0.009 0.017 203308 0.028 1.08 14.1 880288 11.7 8.13M6-1-2 17.8 51.8 20.4 38.5 6.5 0.12 0.322 134 0.16 77 0.756 0.09 178922 0.143 1.55 1.15 0.052 875992 1.79 0.890M6-1-3 34.1 20.7 3880 1621 10.4 1.38 23.6 1328 0.88 187 1.37 0.64 0.008 178967 0.248 1.37 0.92 0.022 877491 22.3 1.73M6-1-4 9.64 4.06 405 617 1.74 0.25 7.86 61.7 53.5 0.198 0.2 0.003 170699 0.135 0.112 3.76 877491 1.91 4.63M6-1-5 10 157 369 169 34.3 0.47 0.615 19.0 0.08 146 1.32 4.02 175335 0.280 0.78 0.25 0.316 880288 1.82 0.158M6-1-6 14.4 6.43 290 279 0.66 0.26 2.64 44.8 0.33 177 0.181 0.42 0.01 168399 0.060 0.74 873792 11.2 0.201M6-1-7 0.830 11.5 17 1.92 0.13 0.058 211 0.591 0.1 0.004 167412 0.085 1.64 0.020 873792 0.016 0.017M6-1-8 34.6 15.2 740 626 81.6 1.45 7.45 87.1 167 0.547 2.72 191465 0.144 1.08 2.94 0.041 875992 2.79 2.55M6-1-9 21.1 5.66 90.4 1287 3.63 0.26 6.96 25.8 59.1 0.27 0.56 0.007 185262 0.083 0.65 0.035 880288 1.76 0.600M6-1-10 0.370 66.9 21.6 2.03 0.22 254 0.269 0.003 175400 0.303 877491 0.068 0.026M6-1-11 33.9 13.3 1491 2567 4.66 0.56 23.1 282 69.5 0.41 1.49 190493 0.261 1.2 0.015 877491 4.2 3.60   27  Table 4.4. Trace element composition of gold Analysis25Mg27Al29Si43Ca46Ti52Cr55Mn57Fe60Ni63Cu66Zn75As103Rh105Pd109Ag118Sn121Sb125Te195Pt197Au208Pb209BiM6-1-12 570 1720 318 39.1 3.61 0.44 5.89 5497 2.12 104 4.56 0.07 0.003 188901 0.037 0.206 0.97 0.017 878491 0.783 0.730M6-1-13 1.45 3.96 0.96 0.042 365 0.033 0.086 199364 3.36 0.030 873695M6-13-1 1.48 3.52 235 176 3.32 2.37 56.3 187 0.139 0.006 176228 0.035 0.753 0.33 0.030 876194 0.082M6-13-2 0.5 1.58 178 1.21 0.07 0.93 141 291 0.125 0.008 4 122467 0.035 0.172 0.171 0.021 909194 0.178 0.031M6-13-3 1.17 3.83 2.01 0.014 304 0.103 0.008 3.95 119765 0.014 0.225 0.123 0.035 906695 0.011 0.013M6-13-4 0.22 4.48 1.77 8.73 1.98 0.3 0.533 57.8 218 0.274 0.003 3.36 117344 0.056 0.055 0.373 0.133 908588 0.363 0.607M6-13-5 1.29 1.52 21.1 14.6 1.11 0.31 0.052 243 0.315 0.004 3.63 125755 0.048 0.058 0.319 908156 0.195 0.508A27-1-1 545 2.65 46.0 1180 1.83 0.41 12.8 232 0.70 117 0.234 0.2 0.007 0.018 106690 0.037 0.073 0.117 924588 0.089 0.034A27-1-2 1.53 0.934 7.05 3.33 2.87 0.085 5.67 166 0.12 0.004 0.017 97958 0.020 0.008 0.04 0.016 932094 0.817A27-1-3 0.52 0.388 1.1 15.6 1.81 108 0.533 0.07 0.006 102898 0.042 0.031 0.029 924588 0.02A27-1-4 744 2.5 22.9 1018 3.17 0.27 15.7 272 2.07 159 0.722 0.25 0.004 0.025 110142 0.050 0.023 0.316 0.263 932094 0.257 0.128A27-1-5 115 13.2 723.5 167 4.13 0.92 1.9 98 9.23 262 0.759 1.64 0.015 0.038 112518 0.079 0.099 0.356 0.030 929893 1.67 0.337A27-1-6 74.7 158 20.9 59.2 4.63 1.99 0.649 37.1 0.05 163 0.3 0.005 0.029 104522 0.026 0.226 0.181 0.011 924588 0.075 0.034A27-1-7 0.36 0.264 1.69 94.3 0.062 0.01 104704 0.011 0.032 929893 0.002A27-1-8 171 19.1 256 250 3 2.89 2.12 44.8 0.41 222 1.16 3.2 0.013 138481 0.080 0.188 0.83 0.017 924588 0.271 0.146A27-2-1 40 34.3 106 92.2 7.99 0.6 2.24 73.4 0.31 480 4.45 0.79 0.013 114182 0.430 0.109 0.152 0.801 926693 0.72 0.036A27-2-2 7.64 2.98 24.2 25.5 1.55 0.27 0.024 460 0.086 0.33 0.01 0.028 110941 0.023 0.004 0.012 924992 0.126 0.011A27-2-3 2.34 1.97 29.8 9.17 2.54 0.05 0.045 127 0.13 0.07 0.007 0.023 115042 0.028 0.022 0.057 0.007 923272 0.004 0.003A27-2-4 233 821 224 33.7 8.24 2.73 0.229 165 0.7 467 0.488 0.57 0.01 0.023 111001 0.054 0.033 0.63 0.020 924492 0.155 0.314A27-2-5 18.6 10.7 66.5 31.3 6.43 0.49 0.412 19.8 0.44 143 0.626 0.5 0.008 122481 0.288 0.172 0.362 0.066 926453 0.271 0.028A27-2-6 14.8 5.15 87.6 34 1.42 0.33 0.034 0.13 112 0.114 0.53 0.005 0.022 116126 0.027 0.035 0.166 0.023 918092 0.068 0.013A27-2-7 8.44 3.78 34.4 19.3 0.85 0.24 0.018 6.21 109 0.147 0.27 0.007 0.035 116596 0.047 0.011 0.165 0.020 922388 0.112 0.044A27-3-1 110 380 745 2.4 0.22 101 351 0.284 0.08 0.004 128515 0.039 0.81 916228 0.035A27-3-2 389 1414 1676 91.1 10.9 3.81 3.16 543 0.33 146 0.944 0.1 0.006 133861 0.095 2 0.031 917391 0.401 0.34A27-3-3 6.89 3.07 72.1 15.2 1.97 0.42 152 155 0.177 0.68 133811 0.018 0.43 0.135 0.016 921792 0.034 0.32A27-3-4 0.765 8.5 2.24 144 0.101 0.006 126502 0.015 0.142 0.018 914191 0.044 0.013A27-3-5 64.3 431 759 47.8 2.14 1.2 0.754 58 158 0.938 0.75 0.004 140860 0.023 0.10 1.95 916094 0.554 0.24A27-3-6 86.8 263 1881 38.2 4.37 1.67 0.093 94.2 165 0.27 0.57 0.012 136953 0.021 0.102 0.29 0.010 915286 0.064 0.014A27-3-7 23.1 80 25.7 9.61 0.94 1.39 0.046 6.12 144 0.137 0.006 128367 0.028 0.369 0.435 0.009 913691 0.057 0.31A27-3-8 35.3 72 432 37.1 17.3 0.93 0.618 174 168 0.277 0.46 0.009 144413 0.157 0.274 0.038 911587 0.174 0.078A27-3-9 11.5 8.45 52 21.2 0.87 0.43 0.043 147 0.219 0.26 0.005 134322 0.016 0.121 0.273 0.013 915286 0.082 0.146A27-3-10 32.1 13.7 134 52.9 1.37 1.13 0.144 17 159 0.46 0.99 0.016 0.032 142519 0.106 0.43 0.014 916094 0.208 0.071A27-3-11 15.3 85.5 1453 35.3 1.5 1.58 0.248 26.5 141 0.454 0.52 0.01 136943 0.116 0.358 0.016 914191 0.187 0.139A27-3-12 27.5 15.3 139 73.7 1.22 1.98 161 0.88 1.62 0.007 160104 0.160 0.093 0.74 921792 0.219 0.0825)MDLm 0.32 0.087 3.37 5.00 0.35 0.04 0.016 1.95 0.05 0.03 0.014 0.04 0.002 0.014 0.09 0.02 0.004 0.037 0.004 55.8 0.03 0.0026)Std devt 0.68 3.31 21.2 4.12 2.48 2.39 2.17 4.15 2.07 2.16 2.19 3.85 2.26 1.75 5.68 1.65 0.73 2.23 1.25 0.16 2.02 0.8527)Precision 6.79 11.5 65.9 14.5 7.74 8.5 7.59 13.6 7.02 6.76 6.90 8.08 5.67 5.95 5.69 5.59 6.41 18.1 4.11 0.00 6.96 8.738)Accuracy 1.05 1.26 14.8 1.43 1.3 1.45 1.26 1.35 1.07 1.02 1.07 1.24 0.79 0.90 0.18 0.63 0.64 2.5 0.38 0.02 0.31 0.588   28     4.4 Data Processing by Glitter LA-ICP-MS counts per second data for each analyte were converted to concentrations using GLITTER 4.4.2 software. Data reduction was performed with the SEM-analysed Ag concentrations as the internal standard and AuRM2 as the external standard. By default, GLITTER automatically selects an interval where analyte signals reach peak steady-state (during laser firing) in order to calculate concentrations. The graphical output in GLITTER shows that certain groups of elements in certain samples reach peak steady-state at different time intervals. For each LA-ICP-MS gold analysis, analyte concentrations were calculated using peak steady-state signal intervals selected by GLITTER. All spectra were visibly inspected to confirm that the selected intervals were reasonable/optimal.    4.5 Multidimensional Scaling and Bivariate plots Previous work indicates that of numerous exploratory statistical methods, multidimensional scaling (MDS) is particularly useful for uncovering patterns in geochemical data sets (Greenough et al., 2007). Thus, it is used here to find relationships in the processed geochemical data by determining similarities or dissimilarities between the samples from the three ore deposits.  MDS uses the processed gold analyses to generate plots that show the overall relationships between gold grains or relationships between samples.  Samples, and elements in the samples, were compared using MDS in SYSTAT software (Wilkinson et al. 1992). MDS creates “maps” showing relationships between “objects” (Borg and Groenen, 1997). Either samples, or the chemical data describing them, can be compared (used as “objects”). Samples or chemical elements that plot close together on a MDS diagram are “similar”. Points that plot on opposite sides of the diagram are most dissimilar. The MDS procedure is detailed in Greenough et al. (2007).  Bivariate plots were also used to investigate relationships between element pairs. All bivariate plots were created using Excel 2010.            29  Chapter 5.0 Results  One goal of this study is to determine whether the three gold deposits have distinct trace element signatures and to assess the extent of chemical variation within one deposit and one sample. A second objective is to use element relationships in individual deposits to infer what elements may be distinguishing deposits, and ultimately infer what processes impact the composition of native gold. The results are presented in five sections as follows: 1) Gold analyses from all deposits (using chemical data from Table 4.4) are compared using MDS; 2) Gold analyses from all deposits (using only chalcophile and lithophile elements) are compared using MDS; 3) Bivariate plots are created to help identify elements that led to the appearance of the deposit and sample groupings on the MDS diagrams and average values of Au-Ag ratios are calculated for each deposit; 4) MDS diagrams are created using chemical data from individual deposits to look for chemical variation in gold between the deposits; 5) A MDS diagram is created using chemical data from one particular sample to search for chemical variation.    5.1 Gold analysis from all deposits  Figure 5.1 uses MDS to compare element behavior using all analyses in the data set. The diagram was prepared by Z-scoring (standardizing) all elements to put them on the same scale, and an element-versus-element matrix of Pearson correlation coefficients was calculated and used by MDS to create the plot. Fields on the diagram have no statistical significance but surround elements with geochemical characteristics that may reflect the geology of the ore deposit or hydrothermal processes that impact the composition of gold. Elements that plot close to one another behave similarly. Hand-drawn fields emphasize that they form five groups that reflect geochemical characteristics including one lithophile, two chalcophile and two siderophile. From the Figure 5.1 it is observed that Au and Ag plot on opposite sides of the diagram; but, Au and Cu neighbor each other.     30   Figure 5.1. Multidimensional scaling plot of elements using all 64 Au analyses.  To compare samples, the z-scored data set (all elements) was inverted and a matrix of sample-versus-sample Pearson correlation coefficients calculated and processed in MDS to create Figure 5.2. Analyses tend to group according to ore deposit (Fig. 5.2a), but when data are labeled by sample number, analyses from individual samples are associated (Fig. 5.2b).   Figure 5.2. Multidimensional scaling plot of samples using all 64 analyses. a)  Labeled by ore deposits. b) Labeled by samples.       31      5.2 Gold analyses using chalcophile and lithophile elements  Additional MDS plots investigate which geochemical element groups are most effective for separating ore deposits. Chalcophile elements (Cu, Zn, As, Sn, Sb, Te, Pb and Bi) yield similar groupings to those using all the elements from the analyte list (Fig. 5.3a). However, Hollinger and McIntyre show considerable overlap, while Aunor is more distinct. Lithophile elements (Mg, Al, Si, Ca, and Ti) show little ability to distinguish deposits (Fig. 5.3b).   Figure 5.3. a) Multidimensional scaling plot comparing analyses based on chalcophile elements b) Multidimensional scaling plot comparing analyses based on lithophile elements.    5.3 Bivariate plots and Au/Ag ratios  Bivariate plots help investigate which elements are most useful for separating ore deposits. A total of 14 bivariate plots are shown in Fig. 5.4. The 64 Au analyses were used to generate the plots with two exceptions (Ag-As and Ag-Pd). As and Pd have concentrations below the detection limits in some of the samples. The samples that were used to make the Ag-As and Ag-Pd diagrams are listed on their respective plots. Correlation coefficients and probability values were calculated and are displayed on each bivariate plot. Note that for some elements, the y axis is on a Log scale due the large range in concentrations observed.          32      Figure 5.4. Bivariate plots using the 64 Au analyses. Correlation coefficients(r) and probability values (p) were calculated for all the plots.    33  Elements that exhibit positive correlations with Au include Cu (Fig. 5.4). In contrast, elements that show negative correlation with Au are; Ag, Bi, and Pb. The six elements that are most useful for distinguishing ore deposits are: Ag, Cu, Pb, Bi, Sb, and Pd. Ag is generally higher in Hollinger, followed by McIntyre, and Aunor has the lowest Ag concentrations. The Au-Ag bivariate plot exhibits a strong negative correlation (r= -0.95, Fig. 5.4a). Both elements separate the deposits. Aunor has low Ag, whereas Hollinger has high Ag concentrations. Unlike Au-Ag, Au and Cu show a positive correlation, which shows a strong correlation (r= 0.58 Fig. 5.4b). Ag-Cr and Ag-Sb have moderate positive correlation coefficients (r= 0.40, 0.65 respectively). The deposits are distinguished along the Bi, Sb axes with Hollinger showing the highest Sb and Bi concentrations and Aunor showing the lowest concentrations. The two lithophile elements Al and Mg exhibit a strong positive correlation. Possible reasons for this correlation are discussed in the following chapter.   Average Au/Ag ratios were calculated for each deposit to investigate whether the ratio values correspond to mesothermal or epithermal ore deposits and results of these are shown in Table 5.1.  Aunor shows the highest Au/Ag ratio and highest fineness (Fineness= (Au/(Au+Ag)*1000)), followed by McIntyre and Hollinger exhibits the lowest.    Table 5.1. Average Au/Ag ratios and fineness for each deposit. Stdev= standard deviation.   5.4 Gold analyses from individual deposits.  MDS plots were created for each deposit to compare element relationships as well as compare samples within each deposit. Procedures are the same as for creation of Figs. 5.1-5.2 which used all 64 analyses.   A MDS diagram comparing element relationships in Hollinger samples (Au4-16, Au4-18, and Au 4-19) shows chalcophile, lithophile and siderophile element groupings. (Fig. 5.5). Au falls close to Cu and Zn and on the opposite side of the plot from Ag, reflecting relationships consistent with the bivariate plots (Fig 5.4a). It can be seen from Figure 5.5b that individual samples in Hollinger have distinct signatures. Deposit Average Au/Ag number of analyses Stdev Average Fineness Stdev n (Au/(Au+Ag))*1000Hollinger 4.18 19 0.75 803.94 22McIntyre 5.42 18 1.17 840.13 24.6Aunor 7.59 27 0.99 882.06 13.6   34   Figure 5.5.  Multidimensional scaling plots of gold grains from Hollinger. a) relationships between elements in the native gold samples. b) relationships between samples.   Gold analyses for the two samples from McIntyre (Au6-1 and Au6-13) were utilized to produce elemental and sample MDS plots (Fig. 5.6). Similar groups of elements to those obtained for Hollinger (Fig. 5.5) are seen in Figure 5.6a; there are two siderophile, one lithophile and one chalcophile. A few observations can be drawn from Fig. 5.6.: 1) Au and Cu are closely associated as the one in Hollinger; 2) Au and Ag plot on the opposite sides of the diagram; 3) Mg and Al overlap and Fe falls close to Mg and Al; 4) The two McIntyre samples have distinct signatures (Fig. 5.6b).    35  Figure 5.6. Multidimensional scaling plots of gold grains from McIntyre. a) relationships between elements in the native gold samples. b) relationships between samples  Gold analyses for the three Aunor samples (Au27-1, Au27-2 and Au27-3) were employed to generate the elemental and sample MDS plots in (Fig. 5.7). There are four groupings of elements: two siderophile, one chalcophile and one lithophile. Au falls close to Pt and on the opposite side of the diagram from Ag, reflecting relationships that are consistent with Hollinger and McIntyre (Fig. 5.5a and Fig. 5.6a). Gold analyses for samples Au27-1 and Au27-2 fall close to one another and on the opposite side of the plot from Au27-3 (Fig. 5.7b).     Figure 5.7. Multidimensional scaling plots of gold grains from Aunor. a) relationships between elements in the native gold samples. b) relationships between samples    36     5.5 Gold analyses from an individual sample.  Chemical variation manifested in groupings of chalcophile, siderophile, and lithophile elements in individual deposits (Figs. 5.5a-5.6a-5.7a) is replicated by variation within an individual sample that lead to analogous groupings (e.g. Aunor sample Au27-1; Fig. 5.8).  Figure 5.8. Elemental MDS plot showing relationships between elements in gold analyses from Au27-1 (Aunor deposit).            37  Chapter 6.0 Discussion This section begins with a brief comparison of the data presented here with analyses in the literature. Next, chemical variation in native Au at a regional, deposit, and sample scale is discussed. Patterns in element behaviour are also examined. In addition, the occurrence of trace elements in native Au (solution versus inclusions) is discussed. The significance of variations in Au/Ag ratios and fineness are then evaluated. Additionally, variations in composition related to the local environment are addressed.    6.1 Geochemical data comparison with previous studies. Researchers such as Townley et al. (1995); Knight et al.( 1999); Hauptmann et al. (1995); Grigorova et al. (1998); Chapman et al.( 2000, 2001, and 2006); Miller et al. (2001) and Palacios et al. (1999) have detected six elements in native Au using the electron microprobe technique (EMP). Three of these (Ag, Cu, and Hg) were commonly reported. Six studies (Watling et al.1994; McCandless et al. 1997; Outridge et al.1998; Penney 2001; Brown et al. 2003; McInnes et al. 2008) have detected forty three elements using solution and laser ablation ICP-MS. Elements that were commonly detected include Cu, Bi, Ag, and Pd. Elements that have never been reported in the previous studies, such as Rh, Ca, and Al, but have acceptable values of precision and accuracy, are reported in this study (e.g. precision and accuracy of Rh are 5.57, and 0.79% respectively, see Table 4.4). Sb, Sn, and Ni are significant in the three deposits; however, these elements were not frequently noted in previous studies. Further, Se was reported by Outridge et al. (1998) and Penney (2001), but it was not detected in this study, confirming that Hollinger, McIntyre, and Aunor have their own regional geochemical signature.     6.2 Chemical variation at a regional, ore deposit, and sample scale. Overall, the gold grains analyzed from the ore deposits of this study show differences in the composition of trace elements amongst themselves. The groups of elements that best fingerprint deposits are the chalcophile (Cu, Zn, Bi, Sb, Pb, As and Sn) and the siderophile elements (Ag, Pd). Lithophile elements (Mg, Al, Ca, Si, Ti and Fe) are not very advantageous for separating ore deposits. Lithophile elements plot together on the MDS elemental diagrams (e.g. Fig. 5.7), but they do not characterize deposits (Fig. 5.3b). One reason for this result could be that some lithophile elements have poor precision values (e.g. precision of Si is ± 65% see Table 4.4). Another possible reason for this result is that lithophile element concentrations may reflect the occurrence of mineral micro inclusions. The issue of micro inclusions in native gold is discussed in the section 6.4. Other elements that appear of limited use for characterizing deposits are Pt, Rh and Te. Penney (2001) found that Te was one of the elements that showed regional chemical differences. It can only be speculated as to why Pt, Rh and Te are not important characteristics of the gold signature, but these elements are normally associated with mafic rocks. Possibly chemical variation (Pt, Rh, and Te) between deposits was not observed because the three deposits are all hosted in similar rock units (metamorphosed mafic-   38  ultramafic rocks). The importance of host rocks and local geology reflected in native gold is discussed later (section 6.6).  Hollinger and McIntyre have similar trace element abundances exhibiting high Ag, Pb, Bi, Sb and Pd and low Cu; however, Cu concentrations in McIntyre are higher than in Hollinger. In contrast, Aunor has high Cu relative to McIntyre but has low Ag, Bi, Sb, Pb and Pd relative to both Hollinger and McIntyre. Some elements that display no average chemical variations between the three deposits do display distinction between samples from one deposit, including Cr, As, and Ni. For example, analyses of As in samples Au4-19, Au6-13 fell below detection limits (see Table 4.4). Elements that display chemical variation within an individual sample (Au27-1), include As, Pb and Bi. Pb and Bi plot together on the elemental MDS plots (Figs. 5.5-5.6, and 5.7), including the elemental MDS plot of sample Au27-1 (Fig. 5.8).     6.3 Patterns in element behaviour. Important patterns in element behavior are:  Ag behaves indirectly proportional to Au; as Ag goes up, Au goes down. This pattern is explained by simple dilution: analyses must sum to 100% and Ag is the most abundant element next to Au. As suggested by the regional and individual deposit MDS diagrams and as shown by bivariate plots, Au exhibits a positive correlation with Cu and Zn which is the opposite of a dilution effect. Direct correlations between Au and Cu and Au and Zn have not been established previously, however, Penney (2001) and Brown et al. (2003) observed that Cu and Zn correlate positively in native Au analyses. Possible causes are discussed in subsequent sections.   Hand-drawn fields around elements according to geochemical character (MDS diagrams, Figs. 5.5-5.6-5.7 and 5.8) demonstrate that element behavior in the native Au is not random. Such element behavior indicates that samples from each deposit formed under similar geological conditions. Elements in native gold associate according to Goldschmidt’s classification of elements (Goldschmidt 1937). Similar results were obtained by McInnis et al. (2008); they found that elements plot coherently as chalcophiles, siderophiles and lithophiles. It is important to note that some elements behave differently based on the character of the chemical system being examined. Anomalies in element behaviour suggest that a small number of geochemical processes operating to varying degrees between deposits, between samples in a deposit and even within a deposit, can affect the distribution of trace elements in gold. Samples in any geochemical data set that have been affected by different geochemical processes and/or partially overprinted by multiple processes will have elements that tend to show random behaviour. For example, only one chalcophile group was found in the MDS diagrams of each deposit; in contrast, two chalcophile groups where obtained when the MDS was done using all 64 analyses in Fig. 5.1.    39  Two groups of siderophiles were observed on all elemental MDS plots (Figs. 5.1-5.5a-5.6a-5.7a-5.8) One group of elements correlates positively with Au (Pd, Pt, and Rh) and the other group correlates positively with Ag (Fe, Ni and Cr). The Platinum group of elements (PGEs) behave most like Au. A possible explanation is that PGEs are normally associated with mafic rocks. The deposits studied here are hosted in mafic to ultramafic rocks. The association could be explained by hydrothermal solutions passing through the host rock and picking up these siderophilic elements for later deposition in/with Au. Lithophile elements are not very useful for distinguishing deposits. However, they tend to correlate better with one another than with chalcophile and siderophile elements causing them to plot together on MDS.    6.4 Occurrence of trace elements in native gold.   Concentrations of trace elements in native gold may reflect mineral micro inclusions but there are also arguments supporting the idea that trace elements occur in solution. However, there is no conclusive evidence regarding how trace elements occur in native Au. Micro inclusions of both opaque and transparent minerals within native gold grains have been noted by various scholars (e.g. Desborough et al. 1970; Loen, 1993; Lange and Gignoux, 1999). Opaque micro inclusions usually exhibit maximum dimensions of between 3 and 20um and may be manifested either as irregular blebs or euhedral particles. Inclusions may be monomineralic or contain complex associations of several phases.  Typically, the most common group of mineral inclusions found in mesothermal gold are sulphides, tellurides, arsenides, and selenides (Chapman et al. 2000). An association of Fe and As was found by McInnis et al. (2008) suggesting that the behaviour of some elements is controlled by micro inclusions such as arsenopyrite. They also found that Fe is closely associated with Pt, Pd and Ag which, based on laser-probe ICP-MS studies of native gold appear to be dissolved in Au (Miller et al. 2001; Penney, 2001). Further, the concentrations of these elements fall within the range reported from laser ablation ICP-MS studies of native gold (e.g. native gold from prospects in central Newfoundland; Penney, 2001). Figure 5.4m shows a positive linear correlation between Sb and Te similar to that found by McCandless et al. (1997). They concluded that it is unlikely that linear correlations found between trace elements are due to fortuitous analysis of micro inclusions in the gold suggesting that Te, Sb, Cu and Hg occur in solution in Au. The strong correlations observed in this study (e.g. Figs. 5.4a-5.4b-5.4c-5.4d-5.4e-5.4f) support previous speculations that trace elements can occur in solution (Boyle 1979 and Watling et al.1994) rather than being present as isolated microinclusions of sulphide or telluride minerals.  Lithophile elements occur in gold as contaminants in the form of lattice impurities or discrete mineral inclusions, which are not usually an intrinsic part of the alloy (Chapman et al. 2000a). Lithophile elements do not correlate with Au or Ag and do not characterize deposits or    40  samples, but they do correlate with one another. Perhaps the strongest case for inclusions in native gold is with these elements. This can be explained by the fact that the presence of micro inclusion minerals bearing these elements reflects localized kinetic processes (e.g. nucleation).  Close association of Al-Mg (and in some cases Ca) on MDS diagrams indicates a mineral or minerals where these are important elements. The ratio of Al2O3 to MgO in Au from each deposit was calculated and compared with tourmaline analyses from Deer et al. (1974). A typical ratio for tourmaline is 2.25 which resembles the ratios found for the three deposits (3.2, 2.6 and 1.5 for Hollinger, McIntyre and Aunor respectively). Tourmaline is a widespread and commonly abundant constituent of the quartz-carbonate veins where gold occurs (see summary of sample petrography Table 3.2). It is interpreted therefore, that tourmaline may occur as micro inclusions in the three deposits. Sulphides such as sphalerite, galena, chalcopyrite, and arsenopyrite occur in whole rock samples from all of the deposits but vary in abundance between deposits. As mentioned above, sulphide inclusions in native Au were not observed. Chalcopyrite is a common mineral in the area and a sulphide with both Fe and Cu stoichiometric components. Fe and Cu do not associate (refer to MDS diagrams) suggesting that chalcopyrite inclusions hosting Cu do not control Cu. The possibility that some other mineral hosting Fe dominates Fe concentrations can be ruled out because Fe concentrations are far below those of Cu. Because the Fe-Cu relationship provides no evidence for chalcopyrite, the most likely Cu-bearing mineral, and the positive relationship with Au indicates the element is dissolved in Au. Further, Ag and Cu are routinely detected in native gold using the electron microprobe and known to be in solid solution (Chapman et al 2000). If there is a significant mineral inclusion (arsenopyrite) controlling Fe and As, these two elements should associate on MDS diagrams. This is possible with Hollinger (Fig. 5.5a), but for McIntyre and Aunor Fe and As plot apart on MDS diagrams (Figs. 5.6a-5.7a), which argues against arsenopyrite controlling Fe and As and supports the hypothesis that As is also dissolved in the Au structure.  The second most common group of micro inclusions in mesothermal gold is the telluride group (Chapman et al 2001). However, no geological reports on telluride minerals occurring in the mines of the Porcupine Mining District were found. Ag-tellurides or Ag-bearing sulphide (argentite) are more typical in epithermal gold deposits and a direct association between argentite and native Au does not seem to be common (Schwartz, 1944). Concentration of Te does not vary within the ore deposits. Hollinger and McIntyre display similar ranges of Te values and Aunor has the lowest Te concentrations. Te correlates positively with Ag (e.g. Figs 5.8-5.7) which appears to be in solution with concentrations antithetic to Au due to dilution. The consistency in Te contents within the three mines and a positive association with Ag strongly suggests that Te occurs in solid solution within the gold. The selenides group is the least likely group of minerals to occur as microinclusions in the gold grains analyzed because 90% of the Se    41  concentrations were below detection limits. Se data were not used for the fingerprinting analysis.    6.5 Variations in Au/Ag ratio. Mesothermal Au deposits typically have Au/Ag ratios from 10(normal) to 1(less common) whereas epithermal Au deposits exhibit a higher Au/Ag ratio from 0.02 to 1 (Groves et al. 1998). Ratios obtained for the three ore deposits fall into the mesothermal range. Aunor exhibits the highest Au/Ag ratio followed by McIntyre and then Hollinger (7.59, 5.42, 4.18 respectively). The three deposits have chemical characteristics consistent with a mesothermal origin. As reviewed in Chapman and Mortensen (2006), compared to epithermal Au, mesothermal Au generally shows a low range of Ag contents and high fineness. Fineness values of 775-905 were obtained for the three deposits (compare Table 5.1) which are consistent with the values of fineness obtained by McInnes et al. (1998) for mesothermal Au. Studies of mesothermal gold from Malaysia (Henney et al. 1994), Great Britain and Ireland (Chapman et al. 2000) and the Klondike District (Dumula and Mortensen, 2002) all show that gold derived from a single mesothermal mineralizing event exhibits a relatively narrow range of alloy compositions. In contrast, ore formation in epithermal environments commonly results from cooling, boiling and/or mixing of ore fluids either individually or in combination, which can result in the precipitation of precious metals from both bisulphide and chloride complexes. Consequently the fineness of gold precipitated in these environments can show a large range range of values from 0 to 1000. Morrison et al. (1991) confirmed that the range in alloy composition of gold grains from an individual epithermal mineralizing events is also very large. The temperature of the hydrothermal fluid is reflected in the Ag and Cu concentrations in native gold. At higher temperatures of ore formation, gold has low Ag and high Cu but at lower temperatures of ore formation, Ag is high and Cu is low (Chapman and Mortensen 2006). Variations of Ag and Cu within the three deposits may reflect the differing conditions of Au-Ag-Cu deposition within hydrothermal systems. Low concentrations of Ag, high fineness and high concentration of Cu for Aunor may indicate that the hydrothermal fluid that formed the Aunor ore deposit had a higher temperature than the McIntyre and Hollinger deposits. This study indicates that elements correlating with either Ag or Cu such as Sb, Pb, Bi and Zn may also be controlled by the temperature of the hydrothermal fluid.    6.6 Chemical variations related to the local environment.   The deposits show significant variation in native gold composition. In most types of mineralization, such as hydrothermal veins, the gold grain signature reflects the chemical characteristics of the host rock superimposed on the chemical signature of the mineralizing fluid (Chapman et al. 2000). This can result in subtle differences in grain chemistry within the same mineralized area, such as observed here between samples from the same ore deposit.    42  One example of these differences is the sample Au4-18 has the highest Cr concentrations among the Hollinger samples. Chrome mica occurs in fracture planes of Au4-18 (see Table 3.1). Cr is found as a major constituent in chromium-rich micas (fuchsite), a very common accessory mineral in Archean greenstone belts. A second example of these chemical differences is the McIntyre Au6-13 sample exhibits the highest concentrations of Cu out of all samples analyzed. McIntyre is in close proximity to the Pearl Lake Porphyry unit which hosts a disseminated Cu-Au-Mo deposit (Davies 1976). Penney (2001) found high Cu concentrations in Au samples close to a gold occurrence that is adjacent to a Cyprus style (Cu-Zn) volcanogenic massive sulphide (VMS) occurrence indicating a local input of Cu. Thus, Cu enrichment in Au samples from McIntyre may be due to the local input of Cu from the nearby Cu-Au-Mo occurrence. Hollinger and McIntyre exhibit higher concentrations of Pb and Bi relative to Aunor. Hollinger and McIntyre mineralization is hosted in metamorphosed volcanic-sedimentary rocks. These rocks may be enriched in Pb and Bi and the enrichment of Pb-Bi in native gold may reflect that moreover Bi can occur in variable amounts in Pb-bearing minerals such as galena which is associated with Au grains in Hollinger and McIntyre. In many Archean gold deposits, galena is a late mineral. Since gold is usually the last mineral in the paragenetic series, the two minerals often occur together (Schwartz, 1944). The presence of Pb-Bi-Cu bearing sulphides such as galena+chalcopyrite is consistent with hydrothermal fluids with high concentrations of these elements. Any Pb-Bi-Cu or trace element in the ore forming fluid may partition into the native gold phase, thus leading to high Pb, Bi, and Cu concentrations in the gold.                 43  Chapter 7.0 Conclusions and Recommendations This study reports the first quantitative analyses for Rh, Ca, and Al in native Au. Concentrations of Rh were not helpful to distinguish the three ore deposits studied in this project, however, they may be used to characterize ore deposits hosted in felsic rocks.  Similarly, although lithophile elements such as Ca and Al do not appear useful for fingerprinting, they may provide clues to the identification or presence of mico-inclusion minerals. In general, most of the 22 elements analyzed have acceptable/useful values of precision, accuracy for trace element analysis. The most accurate and precise elements are Au, Ag, Pd and Pb with lithophile elements having the least precise and accuracy values.  Overall, the gold grains from the three Timmins deposits show differences in trace element composition. The groups of elements that best fingerprint deposits are the chalcophile (Cu, Zn, Bi, Sb, Pb, As and Sn) and the siderophile elements (Ag, Pd). Lithophile elements (Mg, Al, Ca, Si, Ti and Fe) are not very advantageous for separating ore deposits. Chalcophile and siderophile elements appear to be in solid solution in Au whereas lithophile elements concentrations may reflect micro inclusions in Au such as tourmaline.  Hollinger and McIntyre have similar trace element fingerprints with high Ag, Pb, Bi, Sb and Pd and low Cu; however Cu concentrations in McIntyre are high relative to Hollinger. In contrast, Aunor has high Cu relative to McIntyre and low Ag, Bi, Sb, Pb and Pd relative to Hollinger and McIntyre. Trace elements in native Au associate according to Goldschmidt’s classification of elements demonstrating that element behavior in the native Au is not random. Such element behavior suggests that samples from each deposit formed under similar geological conditions. Anomalies in element behaviour between deposits imply that samples were affected by different geochemical processes and/or partially overprinted by multiple processes. The deposits have chemical characteristics (Au/Ag ratios) consistent with a mesothermal origin. In most types of mineralization, such as hydrothermal veins, the gold grain signature reflects the chemical characteristics of the host rock superimposed on the chemical signature of the mineralizing fluid. The association of Pb-Bi-Cu bearing phases such as galena and chalcopyrite with gold supports hydrothermal fluids with high concentrations of these elements. Recommendations for future work include: A certified Au standard including more chalcophile and siderophile elements may be useful for more detailed fingerprinting gold. Thus, chalcophile elements, such as Cd, Ga, Ge, Hg, In, Po, S, Tl, Mo, and siderophilic elements, including Co, Ir, Os, Ru, would be helpful to have in an Au standard.     44  It would be worthwhile to compare the data obtained here to epithermal Au to look at whether trace elements in epithermal Au differ from those commonly found in mesothermal Au and also search for relationships between trace elements in epithermal Au.  Although mineral inclusions were not seen and no attempt was made to study them, it is recommended that this type of research occur because Chapman et al. (2000) and Chapman and Mortensen (2006) showed that, like the composition of the Au itself, they can fingerprint individual deposits.                       45     Bibliography Antweiler, J.C. and Campbell, W.L. 1977. Application of gold compositional analyses to mineral exploration in the United States. Journal Geochemistry Exploration, 8: 17-29. Antweiler, J.C. and Campbell, W.L. 1982. Gold in exploration geochemistry. In: A.L. Levinson (Editor), Precious Metals in the Northern Cordillera. Association of Exploration Geochemestry. Calgary. pp. 33-44. Ayer, J.A., Trowell, N.F., Amelin, Y., and Corfu, F. 1998. Geological compilation of the Abitibi greenstone belt: Toward a revised stratigraphy based on compilation and new geochronology results: Ontario Geological Survey Miscellaneous Paper 169. pp. 4-1–4-14. Ayer, J.A., Ketchum, J., and Trowell, N.F. 2002. New geochronological and neodymium isotopic results from the Abitibi greenstone belt, with emphasis on the timing and the tectonic implications of Neoarchean sedimentation and volcanism: Ontario Geological Survey Open File Report 6100. pp. 5-1–5-16. Ayer, J.A., Thurston, P. C., Bateman, R., Dubé, B., Gibson, H. L., Hamilton, M. A., Hathway, B., Hocker, S.M., Houlé, M., Hudak, G.J., Ispolatov, V., Lafrance, B., Lesher, C.M., MacDonald, P.J., Péloquin, A.S., Piercey, S.J., Reed, L.E., and Thompson, P.H. 2005. Overview of results from the Greenstone Architecture Project: Discover Abitibi Initiative. Ontario Geological Survey Open File Report 6154, 125 p. Bateman, R., Ayer, J.A., and Dube, B. 2008. The Timmins-Porcupine gold camp, Ontario: Anatomy of an Archean greenstone belt and ontogeny of gold mineralization. Economic Geology, 103: 1285-1308.  Bell, K., Anglin, C.D., Franklin, J.M. 1989. Sm-Nd and Rb-Sr isotope systematics of scheelites: possible implications for the age and genesis of vein hosted gold deposits. Geology, 17: 500-504. Borg, I., Groenen, P. 1997. Modern Multi-dimensional Scaling. Springer, Berlin. Brisbin, D.I.1997. Geological setting of gold deposits in the Porcupine Gold Camp, Timmins, Ontario: Ph.D. Thesis, Queen’s University, Kingston, Ontario, 523p. Brown, S.M., Johnson, C.A., Watling, R.J., and Premo, W.R. 2003. Trace element fingerprinting of ancient Chinese gold with femtosecond laser ablation-inductively coupled mass spectrometry. Journal of Archaeological Science, 36: 461-466.     46  Burrows, D.R and Spooner, E.T.C. 1986. The McIntyre Cu-Au Deposit, Timmins, Ontario, Canada; An International Symposium on the Geology of Gold; edited by A.J. Macdonald. Toronto. pp. 23-39. Cameron, E.M., and Hattori, K. 1987. Archean gold mineralization and oxidized hydrothermal fluids. Economic Geology, 82: 1177-1191.  Chapman, R.J., Leake, R.C., Moles, N.R., Earls, G., Cooper, C., Harrington, K., and Berzins, R. 2000. The application of microchemical analysis of alluvial gold grains to the understanding of complex local and regional gold mineralization: A case study in the Irish and Scottish Caledonides. Economic Geology, 95: 1753-1773.  Chapman, R.J., Leake, R.C., and Moles, N.R. 2001. The use of microchemical analysis of alluvial gold grains in mineral exploration: experiences in Britain and Ireland. Journal of Geochemical Exploration, 71(3): 241-268. Chapman, R.J., Leake, R.C., Styles, M. 2002. Microchemical characterization of alluvial gold grains as an exploration tool. Gold Bulletin, 35(2): 53-66.  Chapman, R.J., and Mortensen, J.K. 2006. Application of microchemical characterization of placer gold grains to exploration for epithermal mineralization in regions of poor exposure. Journal of Geochemical Exploration, 91: 1-26.  Davies, J.F. 1976. Structural interpretation of the Timmins Mining area, Ontario. Canadian Journal of Earth Sciences, 14: 1046-1053.  Davies, J.F and Lutha, L.E. 1978. An Archean “Porphyry-type” disseminated Copper Deposit, Timmins, Ontario: Economic Geology, 74: 383-396.  Davies, J.F., Whitehead, R.E., Huang, J., and Nawaratne, S. 1990. A comparison of progressive hydrothermal carbonate alteration in Archean metabasalts and metaperidotites. Mineral Deposita, 25: 65-72.  Deer, W.A., Howie, R.A., Zussman, J. 1966. An introduction to the rock forming minerals. London, Longman Group Limited.  Desborough, G.A., Raymond, W.H., Lagmin, P.J. 1970. Distribution of silver and copper in placer gold derived from the northeastern part of the Colorado Mineral Belt. Economic Geology, 65: 937-944.  Dube, B., and Gosselin, P. 2007. Greenstone-hosted quartz-carbonate vein deposits. Geological Association of Canada, Mineral deposits Division, Special Publication, 5: 49-73.     47  Duff, D. 1982. The petrology and geochemistry of rocks associated with gold deposits, Timmins area, Ontario, Canada: Unpub. M.Sc. Thesis, Sudbury, Laurentian University. 124 p.  Dunbar, W.R. 1948. Structural relations of the Porcupine ore deposits. Canadian Institute of Mining and Metallurgy JubileeVol. pp. 442-446.   Ferguson, S. 1968. Geology and ore deposits of Tisdale Township. Ontario Department of Mines. Geological Report 58.  Fryer, B.J., Kerrich, R., Hutchinson, W., Peirce, M.G., and Rogers, D.S. 1978.  Archaean precious-metal hydrothermal systems, Dome Mine, Abitibi Greenstone Belt. I. Patterns of alteration and metal distribution. Canadian Journal of Earth Sciences, 16: 421-439.  Fryer, B.J., Jackson, S.E., and Longerich, H.P. 1995. The design, operation and role of the laser ablation microprobe coupled with an inductively coupled plasma; mass spectrometer (LA-ICP-MS) in the earth sciences. Canadian Mineralogist, 33(2): 303-312.  Gebre-Mariam, M., Hagemann, S.G., Groves, D.I. 1995. A classification scheme for epigenetic Archaean lode-gold deposits. Mineral Deposit Letters, 30: 408-410.  Goldfarb, R.J., Groves, D.I., and Gardoll, D. 2001. Orogenic gold and geologic time: A global synthesis: Ore Geology Reviews, 18: 1-75.  Gosselin, P., and Dube, B. 2005. Gold deposits of the world: distribution, geological parameters and gold content: Geological Survey of Canada, Open File 4895, (CD-ROM).  Goldschmidt, V. 1937. The principles of distribution of chemical elements in minerals and rocks. The seventh Hugo Müller Lecture, delivered before the Chemical Society. Journal of the Chemical Society. pp. 655–673.  Gray, A.L. 1985. Solid sample introduction by laser ablation-inductively coupled plasma-source mass spectrometry. Analyst, 110: 551-556.  Gray, M.D., and Hutchinson, R.W. 2001. New evidence for multiple periods of gold emplacement in the Porcupine miming district, Timmins area, Ontario, Canada. Economic Geology, 96: 453-475.  Greenough, J.D., Dostal, J., and Greenough, L.M. 2007. Incompatible element ratios in French Polynesia basalts: describing mantle component fingerprints. Australian Journal of Earth Sciences, 54: 947-958.     48  Grigorova, B., Smith, W., Stulpner, K., Tumilty, J.A., and Miller, D. 1998. Fingerprinting of gold artifacts from Mapungubwe, Bosutswe and Thulamela. Gold Bulletin, 31: 99-102.  Groves, D.I., Goldfarb, R.J., Gebre-Mariam, M., Hagemann, S.G., and Robert, F. 1998. Orogenic gold deposits: A proposed classification in the context of their crustal distribution and relationship to other gold deposit types. Ore Geology Reviews, 13: 7-27.  Hauptmann, A., Rehren, T.H., and Pernicka, E.1995. The composition of gold from the mining district of Verespatak/rosia Montana, Romania. In Prehistoric gold in Europe. Edited by G. Morteani and J.P.Northover. Kluwer Academic Publishers, Netherlands. pp 369-381.  Hedenquist, J.W., Ezawa, A., Arribas A., and White, N.C. 1996. Epithermal gold styles: characteristics and exploration. Resource Geology. Especial Publication, Number 1. Society of resource geology.  Henney, P.J., Styles, M.T., Bland, D.J., and Wetton, P.D. 1994. Characterization of gold from the Lubuk Mandi area, Terengganu, Malaysia: British Geological Survey Technical Report WC/94/21. 28p.  Hodgson, C.J., and MacGeehan, P.J. 1982. Geological characteristics of gold deposits in the Superior Province of the Canadian Shield. Canadian Institute of Mining and Metallurgy, Special Volume, 24: 211-229.  Hutchinson, R.W. 1993. A multi-stage, multi-process genetic hypothesis for greenstone-hosted gold lodes: Ore Geology Reviews, 7: 349-382.  Jackson, S.E., Longerich, H.P., Dunning, G.R., and Fyrer, B.J. 1992. The application of laser ablation-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) to in situ trace-element determinations in minerals. Canadian Mineralogist, 30: 1049-1064.  Jackson, S.E. 2008. Calibration strategies for elemental analysis by LA-ICP-MS. Paul Sylvestor, editor. Mineralogical Association of Canada. Short course Volume 40. 356p.  Jochum, K.P., Stoll, B., Herwig, K., Willbold, M. 2007. Validation of LA-ICP-MS trace element analysis of geological glasses using a new solid-state 193 nm Nd:YAG laser and matrix-matched calibration. Journal of Analytical Atomic Spectrometry, 22: 112–121.  Joyce, K.D. 2006 . Gold in the Canadian Shield. Rocks and Minerals, 2: 100-113.  Kerrich, R., Goldfarb, R., Groves, D., and Garwin, S. 2000. The geodynamic of world-class gold deposits: characteristics, space-time distribution and origins. Reviews in Economic Geology, 13: 501-551.    49         Keys, M.R. 1940. Paragenesis in the Hollinger veins. Economic Geology, 35: 611-628.  Kogan, V.V., Hinds, M.W., Ramendik, G.I. 1994. The direct determination of trace metals in gold and silver materials by laser ablation inductively coupled plasma mass spectrometry. Analytical Chemistry, 61: 1243-1248.   Knight, J.B., Mortensen, J.K., and Morrison S.R. 1999. Lode and placer composition in the Klondike District, Yukon Territory, Canada: Implications for the nature and genesis of Klondike placer and lode gold deposits. Economic Geology, 94: 649-664.  Lange, I.M., and Gignoux, T. 1999. Distribution, characteristics, and genesis of high fineness gold placers, Ninemile Valley, Central -Western Montana. Economic Geology, 94: 375-386.  Le Guen, M., Lescuyer, J.L., Marcoux, E. 1992. Lead isotope evidence for a Hercynian origin of the Salsigne gold deposit (Sothern massif central France). Mineral Depositia. 27: 129-136.  Loen, J.S., 1993. Implications of changes in placer gold morphology, Pioneer District, Montana. Northwest Geology, 22: 29–41.  Longerich, H.P., Jackson, S.E., Fryer, B.J., and Stron, D.F. 1993. The laser ablation microprobe-inductively coupled plasma-mass spectrometer. Geoscience Canada, 20: 21-27.  Lorsong, J. 1975. Stratigraphy and sedimentology of the Porcupine Group (Early Precambrian) Northeastern Ontario: Unpublished. B.Sc. Thesis, University of Toronto, 42p.  MaCDonald, P.J. 2010. The geology, lithogeochemestry and petrogenesis of intrusion associated with gold mineralization in the Porcupine Gold Camp, Timmins, Canada. Un published Master’s Thesis. Laurentian Universty. Sudbury, On, 188p.   Mank, A.J.G., and Mason, P.R.D. 1999. A critical assessment of laser ablation ICP-MS as an analytical tool for depth analysis in silica-based glass samples.  Journal of Analytical Atomic Spectrometry, 14: 1143–1153.  Marmont, S., and Corfue, P. 1989. Timing of gold introduction in the late Archean tectonic framework of the Canadian Shield: evidence from U-Pb zircon geochronology of the Abitibi Sub province. Economic Geology, 6: 101-111.     50  McCandless, T.E., Baker, M.E., and Ruiz, J. 1997. Trace element analysis of natural gold by laser ablation ICP-MS; a combined external/internal standardization approach. Geostandards Newsletter, 21: 271-278.   McCuaig, T.C., Kerrich, R., Groves, D.I., and Archer, N. 1993. The nature and dimensions of regional and local gold-related hydrothermal alteration in tholeiitic metabasalts in the Norseman goldfields: The missing link in a crustal continuum of gold deposits?. Mineral Deposita, 28: 420-435.  McInnes, M., Greenough, J.D., Fryer, B.J., and Wells, R. 2008. Trace element in native gold by solution ICP-MS and their use in mineral exploration: A British Columbia example. Applied Geochemistry, 23: 1076-1085.  Miller, D., Desai, N., Grigorova, D., and Smith, W. 2001. Trace-element study of gold from southern African archaeological sites. South Africa Journal of Science, 97: 297-300.  Mokgalaka, N.S., and Gardea-Torresday, J.L. 2006. Laser ablation inductively coupled plasma mass spectrometry: principles and applications. Applied Spectroscopy Reviews, 41: 131-150.  Morrison, G.W., Rose, W.J., and Jaireth, S. 1991. Geological and geochemical controls on the silver content (fineness) of gold in gold-silver deposits. Ore Geology Reviews, 4: 333-364.  Murray, S. 2009. LBMA certified reference materials-Gold project final update. Alchemist, 55: 11-12.  Nunes, P. D., and Pyke, D. R. 1981. Time-stratigraphic correlation of the Kidd Creek orebody with volcanic rocks south of Timmins, Ontario, as inferred from zircon U-Pb ages. Economic Geology, 76: 944-951.  Outridge, P.M., Doherty, W., and Gregorie, D.C. 1998. Determination of trace elemental signatures in place gold by laser ablation-inductively coupled plasma-mass spectrometry as a potential aid for gold exploration. Journal of Geochemical Exploration, 60: 229-240.  Penney, G. 2001. Fingerprinting gold using laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS): an exploration tool. Unplublished. Honors Thesis, Memorial University. Newfoundland, 65p.  Palacios, C., Ulloa, C., Sepulveda, F., Maksaev, V., Herail, G., Townley, B., Lahsen, A., and Parada, M. 1999. Morphologic and chemical characteristics of gold grains: Methodological improvements for gold-bearing deposit exploration. In: Active Continental Margins. Comunicaciones, 50: 97-100.     51   Poulsen, K.H., Robert, F., and Dube, B. 2000. Geological classification of Canadian gold deposits. Geological Survey of Canada. Bulletin 540, 106p.  Pyke, D.R. 1980. Relationship of gold mineralization to stratigraphy and structure in Timmins and surrounding area. Ontario Geological Survey, Miscellaneous Paper, 97: 1-15.  Pyke, D.R. 1982. Geology of the Timmins area, District of Cochrane: Ontario Department of Mines. Geological Report, 219. 141p.  Rasmussen, K.L., Mortensen, J.K., and Falck, H. 2006. Morphological and compositional analysis of placer gold in the South Nahanni River drainage, Northwest Territories. Yukon Exploration and Geology, pp. 237-250.  Robert, F., and Poulsen, K.H. 1997. World-class Archaean gold deposits in Canada: An overview. Australian Journal of Earth Sciences, 44: 329-351.  Schlosser, S., Kovacs, R., Pernicka, E., Gunther, D., and Tellenbach, M.  2009. Fingerprints in Gold.  Schwartz, G. 1944. The host minerals of native gold. Economic Geology, 39: 371-411.  Smith, T.J., Cloke, P.L., and Kesler, S.E. 1984. Geochemistry of fluid inclusions from the McIntyre-Hollinger gold deposit, Timmins, Ontario, Canada. Economic Geology, 79:   1265-1285.  Shaheen, M.E., Gagnon , J.E., Fryer, B.J. 2013. Laser ablation of Iron. A comparison between femtosecond and picosecond laser pulses. Journal of Applied Physics. 114, 083110.  Stumpfl, E. F., and Clark, A.M. 1965. Electron-probe microanalysis of gold-platinoid concentrates from Southeast Borneo. Mining and Metallurgy Bulletin, 708: 933-946.  Townley B.K., Herail, G., Maksaev, V., Palacios, C., de Parseval, P., Sepulveda, F., Orellana, R., Rivas, P., and Ulloa, C. 1995. Gold grain morphology and composition as an exploration tool: application to gold exploration in covered areas. Geochemistry: Exploration and Environmental Analysis, 3: 29-38.  Thurston, P.C., Ayer. J.A., Goutier, J., and Hamilton, M.A. 2008. Depositional Gaps in Abitibi Greenstone Belt Stratigraphy: A Key to Exploration for Syngenetic Mineralization. Economic Geology, 103: 1097–1134.     52  Watling, R.J., Herbert, H.K., and Abell, I.D. 1995. The application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to the analysis of selected minerals. Chemical Geology, 124: 67-81.  Wilkinson, L., M. Hill, and E. Vang. 1992. SYSTAT: statistics. Version 5.2 edition. Systat, Evanston, Illinois, USA.  Wood, P.C., Burrows, D.R., Thomas, A.C., and Spooner, T.C. 1986. The Hollinger-McIntyre Au–quartz vein system, Timmins. Ontario Canada; geological characteristics, fluid properties and light stable isotope geochemistry.  Congress 8th, Melbourne1 965. 1: 71-79.                       53     Appendices Appendix A: SEM/EDX Results     54   Ore deposit Sample M.G/Thin sect Analysis Au(weight%) Ag(weight %) Fe(weight%)170 89.58 10.42Au4-16 Mounted grain 171 89.47 10.53173 90.1 9.9174 84.34 15.66175 84.57 15.43176 84.29 15.71Mounted grain 177 84.25 15.7525 84.47 15.5326 83.82 16.18Au4-18 27 84.55 15.4530 84.21 15.7933 84.36 15.6434 84.55 15.45HOLLINGER 35 84.66 15.3436 83.32 16.6837 84.28 15.72Thin section 38 83.84 16.1639 83.65 16.3540 83.93 16.0741 82.43 15.3742 84.02 15.9843 82.13 16.0344 80.99 16.8145 80.49 16.9246 80.78 16.8228 84 1629 84.04 15.9630 84.67 15.3332 84.43 15.57Au4-19 Mounted grain 33 85.35 14.6534 83.96 16.0435 84.8 15.236 84.09 15.9137 84.92 15.0838 84.48 15.52181 88.03 11.97182 87.38 12.62183 87.6 12.4Mounted grain 184 87.75 12.25McINTYRE Au6-1 49 87.85 12.1550 87.73 12.2751 87.37 12.6352 87.62 12.38   55   Ore deposit Sample M.G/Thin sect Analysis Au Ag Fe68 87.95 12.0569 87.99 12.0170 88.07 11.9371 87.72 11.54 0.7472 87.04 12.37 0.5973 88.05 11.95Mounted grain 74 87.78 12.2275 87.8 12.276 88.07 11.9377 88.12 11.8878 88.3 11.779 87.55 12.4580 87.97 12.0381 87.96 12.0482 87.8 12.283 87.37 12.63Au6-1 84 87.81 12.19McINTYRE Thin section 85 87.95 12.0586 87.93 12.0787 87.93 12.0788 87.73 12.2789 88.04 11.9690 88.01 11.9991 87.74 12.2692 87.87 12.1393 88.22 11.7894 88.17 11.8395 87.72 11.42 0.8596 87.93 12.0797 87.59 12.4198 87.93 12.0799 87.18 11.79 1.02100 87.5 11.99 0.51101 86.12 12.5 1.39104 88.16 11.84106 87.85 12.14107 87.86 12.14108 88.27 11.73109 87.86 12.14110 88.15 11.85111 87.46 12.54112 88.09 11.91113 87.94 12.06   56    Ore deposit Sample M.G/Thin sect Analysis Au Ag Fe114 87.57 12.43115 87.67 12.33116 87.51 12.49Au6-1 117 88.05 11.95Thin section 118 87.67 12.33119 87.42 12.58120 87.9 12.1121 88.32 11.68122 88.13 11.87123 88.2 11.841 90.67 9.33Mounted grain 42 90.92 9.0843 90.69 9.3144 91.03 8.97124 91.09 8.91McINTYRE 125 91.22 8.78126 91.09 8.91127 91.34 8.66Au6-13 128 91.14 8.86Thin section 129 90.65 9.35130 91.49 8.51131 91.08 8.92132 91.2 8.8137 91.09 8.91138 91.24 8.76139 90.99 9.01140 91.3 8.7141 90.84 9.161 92.46 7.54Mounted grain 2 93.21 6.793 92.99 7.01143 93.22 6.78144 92.64 7.36Au27-1 145 91.51 7.22 0.58AUNOR Thin section 146 92.7 7.3147 93.11 6.89148 92.95 7.05149 92.45 7.55150 92.26 7.22 0.52   57                    Ore deposit Sample M.G/Thin sect Analysis Au Ag Fe12 91.81 8.1913 92.24 7.76Au27-2 Mounted grain 14 92.3 7.715 92.45 7.5516 92.5 7.5AUNOR 17 92.67 7.3318 91.16 8.8418 91.37 8.6318 91.53 8.47Au27-3 Mounted grain 18 91.61 8.3918 91.42 8.5818 91.74 8.2618 92.18 7.82   58  Appendix B: List of gold grains analyzed      Ore deposit Sample Analysis Ore deposit Sample AnalysisAu 4-16 H4-16-1 Au 6-1 M6-13-1Au 4-16 H4-16-2 Au 6-13 M6-13-2Au 4-18 H4-18-1 McIntyre Au 6-13 M6-13-3Au 4-18 H4-18-2 Au 6-13 M6-13-4Au 4-18 H4-18-3 Au 6-13 M6-13-5Au 4-18 H4-18-4 Au 27-1 A27-1-1Au 4-18 H4-18-5 Au 27-1 A27-1-2Hollinger Au 4-18 H4-18-6 Au 27-1 A27-1-3Au 4-18 H4-18-7 Au 27-1 A27-1-4Au 4-18 H4-18-8 Au 27-1 A27-1-5Au 4-18 H4-18-9 Au 27-1 A27-1-6Au 4-19 H4-19-1 Au 27-1 A27-1-7Au 4-19 H4-19-2 Au 27-1 A27-1-8Au 4-19 H4-19-3 Aunor Au 27-2 A27-2-1Au 4-19 H4-19-4 Au 27-2 A27-2-2Au 4-19 H4-19-5 Au 27-2 A27-2-3Au 4-19 H4-19-6 Au 27-2 A27-2-4Au 4-19 H4-19-7 Au 27-2 A27-2-5Au 4-19 H4-19-8 Au 27-2 A27-2-6Au 6-1 M6-1-1 Au 27-2 A27-2-7Au 6-1 M6-1-2 Au 27-3 A27-3-1Au 6-1 M6-1-3 Au 27-3 A27-3-2Au 6-1 M6-1-4 Au 27-3 A27-3-3Au 6-1 M6-1-5 Au 27-3 A27-3-4Au 6-1 M6-1-6 Au 27-3 A27-3-5McIntyre Au 6-1 M6-1-7 Au 27-3 A27-3-6Au 6-1 M6-1-8 Au 27-3 A27-3-7Au 6-1 M6-1-9 Au 27-3 A27-3-8Au 6-1 M6-1-10 Au 27-3 A27-3-9Au 6-1 M6-1-11 Au 27-3 A27-3-10Au 6-1 M6-1-12 Au 27-3 A27-3-11Au 6-1 M6-1-13 Au 27-3 A27-3-12

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.24.1-0074329/manifest

Comment

Related Items