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Diamonds in an Archean greenstone belt : a study of diamonds and host meta-conglomerate from Wawa (northern… Bruce, Loryn Frances 2011

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DIAMONDS IN AN ARCHEAN GREENSTONE BELT: A STUDY OF DIAMONDS AND HOST META-CONGLOMERATE FROM WAWA (NORTHERN ONTARIO)  by  Loryn Frances Bruce  B.Sc., The University of Massachusetts, 2008  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF  MASTER OF SCIENCE  in  The Faculty of Graduate Studies  (Geological Sciences)  THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  July 2011  © Loryn Frances Bruce, 2011  Abstract I studied a diamondiferous Archean meta-conglomerate from Wawa (North Ontario), part of the Michipicoten Greenstone Belt (MGB) of the Superior Craton. Field observations determined the 170 m thick meta-conglomerate displays poorly sorted, matrix to clast supported and massive to bedded textures. Petrographic and SEM analyses determined it was metamorphosed in the greenschist facies. Twenty-four clast types were identified and classified into groups: igneous with subophitic texture; coarse-grained felsic; vesicular igneous; porphyritic mafic; porphyritic felsic; untextured volcanic; chert-like, unidentifiable clasts rich in chlorite, and opaques. The pebble - cobble sized clasts are derived from nearby meta-volcanic and meta-sedimentary rocks. Predominance of local volcanic clasts confirms the metaconglomerate formed as a Timiskaming type deposit, between 2700.4±1.0 Ma and 2697.2±1.8 Ma. 383 diamonds (<2 mm) extracted from the meta-conglomerate were characterized using morphology, Fourier Transform Infrared (FTIR), and luminescence analyses. These diamonds show octahedral, cuboid, cubo-octahedral, and twinned growth habits; most are unresorbed. These diamonds are classified as Type IaA, Type IaAB, Type II, and Type IaB based on nitrogen contents and aggregation. Their calculated mantle residence temperature is 1000-1200˚C. Characterization of meta-conglomerate diamonds indicates they are cratonic in nature. A primary source is still unknown, speculated to be of mafic to ultramafic composition. Proximal diamondiferous meta-breccia may not be the source of metaconglomerate diamonds, based on comparisons of morphological properties, nitrogen content and aggregation, and host rock mineralogy for meta-breccia and metaconglomerate diamonds. Meta-conglomerate diamonds display a coarser size distribution, more diamond colours, and larger proportion of unresorbed crystals. Both suites are comparable in terms of growth habits and calculated mantle residence temperatures. Despite contrasting traits, meta-breccia and meta-conglomerate diamonds both display green, yellow, orange, pink, and red-orange cathodoluminescence (CL) colours ii  with emittance at 520, 576 nm, and 586 - 664 nm, dissimilar to diamonds in unmetamorphosed rocks that show blue CL colour with emittance at 415 - 440 and 480 490 nm. This shift of CL results from presence of optical centers with zero-phonon lines at 575 and 637 nm detected via photoluminescence (PL) spectroscopy. The centers may have formed due to irradiation of diamonds in the upper crust and annealing.  iii  Preface  Part of the research contained in this thesis has been published in the form of the following manuscript: Bruce, L.F., Kopylova, M.G., Long, M., Ryder, J., and Dobrzhinetskaya, L.F., 2011, Luminescence of diamonds from metamorphic rocks: American Mineralogist, v. 96, p. 14-22. J. Ryder of Dianor Resources, Inc. contributed samples (meta-conglomerate diamonds) and indicator minerals for this study. Additionally, he acted as Leadbetter Property field guide, contributing suggestions and insight regarding field samples and field geology related to this study. M. Longo was responsible for optical and spectral cathodoluminescence (CL) data collection on a portion of the Wawa meta-conglomerate diamonds. L. F. Dobrzhinetskaya also contributed samples (metamorphic diamonds from Kokchetav and Erzgebirge) for analysis. I collected addition optical and spectral CL collection of Wawa meta-conglomerate diamonds as well as of the metamorphic samples. I also wrote the majority of the manuscript with Dr. M. G. Kopylova, who also authored the discussion section in addition to providing editorial comments throughout manuscript preparation.  iv  Table of Contents Abstract...............................................................................................................................ii Preface ............................................................................................................................... iv Table of Contents................................................................................................................ v List of Tables ....................................................................................................................vii List of Figures..................................................................................................................viii Acknowledgements ........................................................................................................... xi Dedication.........................................................................................................................xii Chapter 1: Introduction....................................................................................................... 1 1.1 Introduction .............................................................................................................. 1 1.2 Geologic setting ........................................................................................................ 2 Chapter 2: Unconventional diamond host rocks of Wawa ................................................. 6 2.1 Meta-conglomerate host rocks.................................................................................. 6 2.1.1 Field observations.............................................................................................. 6 2.1.1.1 Meta-conglomerate ..................................................................................... 6 2.1.1.2 Other rocks ............................................................................................... 16 2.1.2 Petrography: optical and SEM......................................................................... 25 2.1.2.1 Meta-conglomerate ................................................................................... 25 2.1.2.2 Other rocks ............................................................................................... 39 2.1.3 Geochronology ................................................................................................ 60 2.1.3.1 Analytical methods ................................................................................... 60 2.1.3.2 Geochronology of the meta-conglomerate ............................................... 61 2.1.4 Interpretation ................................................................................................... 61 2.2 Meta-breccia host rocks.......................................................................................... 66 2.2.1 Field observations............................................................................................ 66 2.2.2 Petrography...................................................................................................... 67 2.2.3 Geochronology ................................................................................................ 67 2.2.4 Interpretation ................................................................................................... 67 Chapter 3: Physical characteristics of diamonds .............................................................. 69 3.1 Morphology and colour of natural diamonds ......................................................... 69 3.1.1 Growth form .................................................................................................... 69 3.1.2 Diamond colour ............................................................................................... 73 3.1.3 Diamond resorption ......................................................................................... 75 3.2 Physical characteristics of meta-Conglomerate hosted diamonds.......................... 79 3.2.1 Size .................................................................................................................. 81 3.2.2 Crystal morphology and growth habits ........................................................... 81 3.2.3 Surface features ............................................................................................... 85 3.2.4 Body colour ..................................................................................................... 86 3.2.5 Degree of resorption ........................................................................................ 86 v  3.2.6 Inclusions......................................................................................................... 86 3.3 Physical characteristics of meta-breccia hosted diamonds..................................... 90 Chapter 4: Infrared absorption properties of diamonds.................................................... 91 4.1 Nitrogen systematics............................................................................................... 91 4.2 Analytical methods ................................................................................................. 96 4.3 Infrared spectroscopy of meta-conglomerate hosted diamonds ............................. 96 4.4 Infrared spectroscopy of meta-breccia hosted diamonds...................................... 100 Chapter 5: Luminescence of diamonds .......................................................................... 101 5.1 Introduction .......................................................................................................... 101 5.2 Analytical methods ............................................................................................... 105 5.3 Luminescence of meta-conglomerate hosted diamonds ....................................... 106 5.3.1 Cathodoluminescence of meta-conglomerate hosted diamonds.................... 106 5.3.2 Photoluminescence of meta-conglomerate hosted diamonds ........................ 106 5.4 Luminescence of meta-breccia hosted diamonds ................................................. 110 5.4.1 Cathodoluminescence of meta-breccia hosted diamonds .............................. 110 5.4.2 Photoluminescence of meta-breccia diamonds.............................................. 110 5.5 Interpretation ........................................................................................................ 113 Chapter 6: Discussion and conclusions .......................................................................... 116 6.1 Meta-conglomerate origin .................................................................................... 116 6.2 Diamond origin..................................................................................................... 119 6.2.1 Cratonic vs. orogenic origin .......................................................................... 119 6.2.2 Did meta-conglomerate hosted diamonds originate from meta-breccia? ...... 121 6.2.2.1 Constraints based on size and crystal growth forms............................... 121 6.2.2.2 Constraints based on colour and cathodoluminescence.......................... 122 6.2.2.3 Constraints based on resorption.............................................................. 122 6.2.2.4 Constraints based on nitrogen systematics ............................................. 124 6.2.2.5 Constraints based on mineralogy and ages of host rocks ....................... 124 6.2.3 Interpretation ................................................................................................. 126 6.3 Origin of unusual cathodoluminescence............................................................... 127 6.4 Conclusions .......................................................................................................... 128 Bibliography ................................................................................................................... 130 Appendices ..................................................................................................................... 141 Appendix A: Field descriptions .................................................................................. 141 Appendix B: Petrographic descriptions ...................................................................... 161 Appendix C: Diamond morphology ........................................................................... 232	
    vi  List of Tables Table 2-1 Description of clasts found within meta-conglomerate ................................... 29  Table 3-1 Explanations for colouration in diamond ......................................................... 74 Table 3-2 Various surface features common in diamond................................................. 78  Table 4-1 Nitrogen analysis results for diamonds in meta-conglomerate ........................ 97 Table 5-1 Cathodoluminescence and photoluminescence results for meta-conglomerate diamonds......................................................................................................................... 108  vii  List of Figures Figure 1-1 Geologic map of Superior Craton ..................................................................... 3 Figure 1-2 Stratigraphic column of Michipicoten greenstone belt (MGB) ........................ 4 Figure 2-1 Overall geologic map of field area.................................................................... 7 Figure 2-2 Geologic map of occurrence of diamondiferous meta-conglomerate............... 8 Figure 2-3 Contact between meta-conglomerate and meta-basalt...................................... 9 Figure 2-4Texture of S1C meta-conglomerate ................................................................. 10 Figure 2-5 Texture of S1CO meta-conglomerate ............................................................. 11 Figure 2-6 Contact between meta-conglomerate and meta-argillite................................. 13 Figure 2-7 Contact between meta-conglomerate and meta-sandstone ............................. 14 Figure 2-8 Photographs of barren meta-conglomerate ..................................................... 15 Figure 2-9 Photographs of meta-conglomerate east of Mildred Lake Fault..................... 17 Figure 2-10 Photographs of intercalated meta-sandstone and meta-argillite ................... 18 Figure 2-11 Photographs of metamorphosed pillow basalt flows .................................... 20 Figure 2-12 Photograph of mafic dyke cross cutting meta-conglomerate........................ 22 Figure 2-13 Photographs of meta-volcanics ..................................................................... 23 Figure 2-14 Photographs of transition between meta-breccia, meta-sandstone, and metavolcanics ........................................................................................................................... 24 Figure 2-15 Photomicrographs of meta-conglomerate textures ....................................... 26 Figure 2-16 Photomicrographs of metamorphic features in meta-conglomerate ............. 28 Figure 2-17 Photomicrographs of clasts in thin section ................................................... 33 Figure 2-18 Photomicrographs of clasts in thin section ................................................... 34 Figure 2-19 Photomicrographs of clasts in thin section ................................................... 35 Figure 2-20 Photomicrographs of clasts in thin section ................................................... 36 Figure 2-21 Photomicrographs of clasts in thin section ................................................... 37 Figure 2-22 Photomicrographs of clasts in thin section ................................................... 38 Figure 2-23 SEM micrograph of clast 1 in meta-conglomerate ....................................... 40 Figure 2-24 SEM micrographs of clast 19 in matrix within meta-conglomerate ............ 41 Figure 2-25 SEM micrographs of clast 5 in meta-conglomerate...................................... 42 Figure 2-26 SEM micrographs of clast 8 in matrix within meta-conglomerate ............... 43 viii  Figure 2-27 SEM micrographs of clast 12 in matrix within meta-conglomerate ............. 44 Figure 2-28 SEM micrographs of clasts in meta-conglomerate ....................................... 45 Figure 2-29 Photomicrographs of clasts in thin section ................................................... 46 Figure 2-30 Thin section and SEM micrographs of meta-argillite................................... 47 Figure 2-31 Photomicrographs of meta-sandstone texture............................................... 49 Figure 2-32 Photomicrographs of meta-gabbro texture ................................................... 50 Figure 2-33 Photomicrographs of meta-peridotite texture ............................................... 52 Figure 2-34 Photomicrographs of meta-andesite texture ................................................. 53 Figure 2-35 SEM micrograph of meta-andesite texture ................................................... 54 Figure 2-36 Photomicrographs of meta-basalt texture ..................................................... 56 Figure 2-37 SEM micrographs of meta-basalt texture ..................................................... 57 Figure 2-38 Photomicrographs of plagioclase poor mafic subvolcanic rock ................... 58 Figure 2-39 Photomicrographs of plagioclase rich subvolcanic rock .............................. 59 Figure 2-40 U-Pb ratios of zircon grain plots from Pts 29, 229 ....................................... 62 Figure 2-41 Weighted averages of 207/206 Pb for Pts 29, 229........................................ 63 Figure 2-42 U-Pb ratios of zircon grain plots from Pts 4, Doré 13 .................................. 64 Figure 3-1 Schematics for atomic structure of diamond and diamond growth ................ 70 Figure 3-2 Schematics for common diamond growth forms ............................................ 72 Figure 3-3 Resorption classification scheme for diamond ............................................... 77 Figure 3-4 Diagram of common surface features on diamonds ....................................... 80 Figure 3-5 Photographs of diamond from meta-conglomerate I ...................................... 82 Figure 3-6 Pie charts of meta-conglomerate diamond growth form ................................ 83 Figure 3-7 Photographs of diamond from meta-conglomerate II..................................... 84 Figure 3-8 Photographs of diamond from meta-conglomerate III ................................... 87 Figure 3-9 Histogram of meta-conglomerate diamond resorption ................................... 88 Figure 3-10 Photographs of diamond from meta-conglomerate IV ................................. 89 Figure 4-1 Diamond classification scheme, based on nitrogen contents.......................... 92 Figure 4-2 Explanation of diamond infrared spectra........................................................ 94 Figure 4-3 Infrared spectra showing degradation of B’ defects ....................................... 95 Figure 4-4 Histogram and plot of meta-conglomerate diamond nitrogen content and aggregation states ............................................................................................................. 99 ix  Figure 5-1 Schematic explaining the nature of luminescence ........................................ 102 Figure 5-2 Photoplates of optical cathodoluminescence of diamonds ........................... 107 Figure 5-3 Cathodoluminescence spectra of metamorphosed diamonds ....................... 109 Figure 5-4 Photoluminescence spectra of metamorphosed diamonds............................ 111 Figure 5-5 Photoluminescence spectra of diamonds in ummetamorphosed rocks......... 112 Figure 5-6 Optical, spectral cathodoluminescence of unmetamorphosed diamonds ..... 114 Figure 6-1 Schematic of depositional facies for meta-conglomerate ............................. 118 Figure 6-2 Comparative histograms of diamond resorption and nitrogen content ........ 123  x  Acknowledgements This thesis would not have been possible without the essential support of my supervisor, Maya Kopylova. I thank her for the hours of leadership she contributed to my progress. The support, availability, and intellect contributed by the other members of my committee, Ken Hickey and Stuart Sutherland, also deserves thanks, as well as the external committee member, Lee Groat. In addition, I thank others who have also contributed insight to my research by way of discussion and suggestions: John Ryder, Kevin Kivi, Thomas Stachel. And I thank Evan Smith for his tireless patience in editing my thesis. Those present in my personal life that helped keep me sane and provide mental breaks from my academic life also merit thanks. I want to thank Kirsten, Heather, Amelia, and Chanone for providing me with all the womanly support I could ever want and introducing me to a variety of things that have enriched my life (i.e. rock climbing, dubstep, etc). I also want to thank my mother, father, and sister for their unending enthusiasm for my thesis and my time at UBC. Although they know little about my research, they also have earned much of my thanks.  xi  Dedication  To my grandmother, Kwak Kwang-Soon.  xii  Chapter 1: Introduction 1.1 Introduction Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites (Scott-Smith, 1995). Erosion of their primary host kimberlite rocks leads to diamonds being deposited into secondary sources such as placers. Later they may form diamondiferous sedimentary rocks, or when metamorphosed, diamondiferous metamorphics. The purpose of this study was to determine the origin of diamonds found within a meta-conglomerate outcropping ~12 km north of Wawa, northern Ontario. These diamonds are unusual because they are hosted in Archean-age meta-sedimentary rocks. The meta-conglomerate unit is of great interest to the mineral exploration company, Dianor Resources, Inc., because 6868 of mostly near-gem or gem quality diamonds have been recovered from initial drilling and subsequent auditing of tailings (Verley et al, 2007). Also, the presence of gold, sapphires, and rubies add to the allure (Press release 18 January 2007, Dianor Resources, Inc.). One possible source for the meta-conglomerate diamonds is nearby Archean diamondiferous calc-alkaline lamprophyres and volcaniclastic breccias (Lefebvre et al, 2005) (both referred to as meta-breccia in this study). This meta-breccia is located ~8 km to the north west of the meta-conglomerate occurrence and also represents an unconventional diamondiferous source. The meta-breccia diamonds are brought up by non-kimberlitic volcanic rocks that formed simultaneously with the mafic and sedimentary rocks of the Michipicoten Greenstone Belt (MGB). To solve this problem, several different types of geological, petrological and mineralogical data were collected. Field observations were used to determine field relationships between meta-conglomerate and meta-breccia. Petrographic examination of thin sections was utilized to compare petrography and mineralogy of meta-conglomerate to meta-breccia. Petrographic studies of meta-conglomerate clasts determined their provenance and possible contribution from lamprophyre. Geochronology was needed in order to determine if ages of the meta-conglomerate allow for inclusion of meta-breccia clasts. Conventional studies of diamond fingerprinting were applied to metaconglomerate diamonds. The first is morphology studies to classify growth habits and resorption features. The second is Fourier Transform Infrared spectroscopy (FTIR) that quantifies nitrogen content and aggregation of diamond in order to classify the diamonds 1  into types and estimate their mantle residence time. Cathodoluminescence (CL) analyses, both optical and spectral, were implemented as well. The study of Wawa meta-conglomerate contributes to our understanding of Michipicoten Greenstone Belt (MGB) formation and possible occurrence of Archean kimberlites or other diamond-bearing volcanics. 1.2 Geologic setting Wawa is located ~230 km north of the large city of Sault St. Marie in the Michipicoten Greenstone Belt (MGB), within the Wawa subprovince of (Figure 1-1). This subprovince makes up some of the Superior Craton’s southwest portion. The Superior Craton is formed by the accretion of a variety of island arcs, oceanic plateaus, and continental fragments (i.e. Polat, 2001). As documented by Condie (1981), the Superior Craton is characterized by supracrustal successions comprised dominantly of mafic volcanic rocks surrounded by granitic rocks, in addition to sedimentary stratigraphic units consisting of mostly greywacke-argillite. The Michipicoten Greenstone Belt (MGB) is approximately 140 km long and 38 km at its widest point, making it the largest of the greenstone belts within the Wawa subprovince (Rice et al, 1992). Three volcanic cycles make up the geology of the belt (e.g. Goodwin, 1962; Sage, 1994; Sage et al, 1996), ages 2900, 2750, and 2700 Ma (Turek, 1982) (Figure 1-2) All cycles consist of intermediate to mafic metavolcanics, capped by intermediate to felsic meta-volcanics that display similar textures and compositions to each other. Cycle 3 is unique in its interfingering relationship with a meta-sedimentary unit to the southwest, the Doré Formation. In addition to the volcanic cycles, intrusive rocks are also present throughout the stratigraphy, mostly sill-like in form and range in compositions from gabbro to quartz diorite. According to U-Pb dating, intermediate to felsic granitic intrusion ages coincide with Cycles 1 and 2 in the supracrustal rocks of Wawa, indicating these intrusions are sources of the subsequent meta-volcanic rocks deposited within each cycles (Sage, 1994). These intrusions surrounded by contact zones. The Michipicoten Greenstone Belt (MGB) is speculated to have a continental origin, with rifting of older continent and its reassembly during the Kenoran orogeny  2  N ba  to ni  a  6210141 mN  M  North Caribou Superterrane English R.  Bird R.  East  Opatica  Wabigoon  Winnipeg R. Quetico  Wawa  Quebec  Wabigoon  Quetico Wawa  Lake Superior Abitibi  igan Mich Lake  La  0  4876249 mN  town of Wawa  rio  nta ke O  n  Michipicoten Greenstone Belt  uro  Subprovince boundaries  eH  Superior Craton  Lak  LEGEND  200  kilometers Scale: 1:5,000,000 312929 mE Figure 1-1 Regional geologic map of Ontario, showing locations of tectonic domains within the Superior Craton. Black area denotes the Michipicoten Greenstone Belt (MGB). Modified after Percival et al (2006).  3  upper volcanics sediments middle volcanics lower volcanics  Apparent thickness (km)  greywacke argillite quartzite arkose shale conglomerate chert, iron formation breccia tuff  flows and sills mafic volcanics ultramafic volcanics  carbonates  Figure 1-2 Generalized stratigraphic column of the Michipicoten Greenstone Belt (MGB) displaying the 3 volcanic cycles making up the belt, ages 2900, 2750, and 2700 Ma, respectively. All cycles consist of intermediate to mafic meta-volcanics, capped by intermediate to felsic meta-volcanics.  4  (e.g. Ketchum et al., 2008; Sage et al., 1996; Thurston, 2002; Ayer et al., 2002). This data is supported by the composition of Cr-garnets indicating a continental setting (Verley et al, 2007 and references therein) and recent studies of U-Pb dating on zircon whereby samples displayed similar ages to underlying assemblages (Ayer et al, 2002). The convergent plate setting model is consistent with the anticlinal structures imposed on early monoclinal north facing stratigraphy seen in the Wawa supracrustal rocks (McGill, 1992; Sage, 1994). While the area displays a general younging direction to the south, individual and local areas have variances of younging direction because of overturned rock packages due to metamorphism (McGill, 1992). Literature data on geology of the meta-conglomerate is reported by Verley et al (2007). This diamondiferous unit occurs as a ~170 m thick bed that is thickest at the center of its outcropping and pinches out towards the northwest (Verley et al, 2007). The meta-conglomerate strikes northwest with a dip of ~45˚ to the northeast (Verley et al, 2007; McGill, 1991).  5  Chapter 2: Unconventional diamond host rocks of Wawa 2.1 Meta-conglomerate host rocks 2.1.1 Field observations 2.1.1.1 Meta-conglomerate As mentioned above, Wawa contains a diamondiferous meta-conglomerate unit (located at the center of the field area, Figure 2-1) and a barren meta-conglomerate unit to the southwest (part of a unit also known as the Doré Formation; Rice et al, 1992). These units are discussed separately in detail below. In the field, they cannot be distinguished. Please refer to Figures 2-1 and 2-2 for reference of all field points described. The lower contact of the main Wawa meta-conglomerate is visible (Pt 5), abutting older meta-basalts of an unknown thickness, though suggested to be at least 1,000 m at an unconformable contact (more details described in the next section). The contact (Pt 5) is occasionally diffuse over ~4-8 cm (Figure 2-3a) or sharp, with a ~5 cm black contact surface between the units (Figure 2-3b). The contact is visible by the change in colour between the meta-basalt and meta-conglomerate and the absence of clasts within the meta-basalt. This main meta-conglomeratic unit is further divided into two sub-units, referred to as S1C and S1CO (“other”) meta-conglomerates (Verley et al, 2007). The S1C meta-conglomerate ranges from matrix to clast supported (Figure 2-4a, b; Pt 2, 153), sorted to unsorted (Figure 2-4c, d; Points 153, 101), and massive to bedded at various intervals throughout the unit. Clasts are subrounded to rounded (Figure 2-4) and 1-20 cm in size, although boulders up to 40 cm in size are present as well (Figure 24). Some bedding is visible, but rarely seen and any grading observed is reversed (indicating overturned beds; Figure 2-4c; Pt 153). All clasts are stretched (Figure 2-4e; Pt 156), but their degree of stretching varies depending on location. These clasts are made of basalt, rhyolite, gabbro, sand- and siltstone, and granite (Figure 2-4g, h; Points 101, 2) set in a finer-grained matrix, tan to brown to reddish brown in colour. The unit is approximately 110 m in thickness (Verley et al, 2007). The S1CO (“other”) metaconglomerate is quite similar regarding clast sizes and matrix to clast ratios, but there are less mafic volcanic clasts present (Figure 2-5a, b; Points 06-74, 05-237). The 6  5337000 mN  15-2 15-115-3 15-4 15-5 Wren 14 15-6 41  41  16-2  t  l Fau  17  5327000 mN  89  34 33  55  38  37  31 30  25  19  22 23 21 20  27  24  35  LEGEND  28  lt  Intermediate-felsic metavolcanics  au F a aw W  4.0  kilometers Scale: 1:102,700  Fault Sample collection point  Mafic-intermediate meta-volcanics Intrusive rocks  87  0  55  Meta-sedimentary rocks  29  Figure 2-2  33-3 32  65  61  58  33-4  18  16-1  ake  39  36  Doré 13  52  dL  gin  un  yo  t  ec  ir gd  Breccia 52  ion  N  E1 BR-1  24  dre Mil  5332000 mN  40  5322000 mN  670000 mE  664000 mE  Main field area 45  strike and dip of bedding  45  trend and plunge of foliation  Figure 2-1 Geologic map showing sampling points of meta-conglomerate within the 2700 Ma volcanic cycle of the Michipicoten Greenstone Belt (MGB). The diamondiferous metaconglomerate is located within the box and shown at a larger scale in Figure 2-2. The barren meta-conglomerate occurs to the southwest (point Doré 13). 7  671000 mE  670750 mE  671250 mE  671500 mE  671750 mE  672250 mE  672000 mE  42  5326000mN 5325750 mN  105  101  t  43  Pit 9  44  LEGEND meta-basalts  SC1 meta-conglomerate  SC1O “other” meta-conglomerate  5325500mN  intrusive rocks  inferred meta-sediments inferred contact  CHAB 06-32  aul  38  119  110  F ke  5326250 mN  44  N  La  7  10  ed ldr  157 4 6 5 156 1 3  138  Mi  05-210  191 05-237 61  06-74  229  Sample collection point 45  strike and dip of bedding  45  trend and plunge of foliation  0  400  meters Scale: 1:2,500  Figure 2-2 Geologic map showing field points found within the diamondiferous meta-conglomerate and its associated contacts. Modifed from Leadbetter Resources, Inc, in house map.  8  a  meta-conglomerate  meta-basalt  b  meta-basalt  meta-conglomerate Figure 2-3 Field photographs of a contact between the diamondiferous meta-conglomerate and meta-basalts; Point 5. The contact can be a) diffuse over ~4-8 cm or b) sharp with a ~3 cm contact zone between the units. The units are distinguished by colour and lack of clasts within the meta-basalts.  9  a  b  c  d  e  f  g  granitic  rhyolite  granitic  h  basalt  gabbro granitic rhyolite  basalt  Figure 2-4 Photographs of S1C meta-conglomerate displaying a) clast supported (Pt 2), b) matrix supported (Pt 153), c) sorted and reverse graded (Pt 153), d) unsorted textures (Pt 101), e) stretched clasts (Pt 156) and containing f-h) gabbro, basalt, rhyolite, granitic clasts (Pt 229, 101, and 2). 10  a  b  c  Figure 2-5 Photographs of S1CO (”other”) meta-conglomerate displaying a) mostly felsic clasts (Pt 06-74), b) rare localized areas where mafic clasts are present (Pt 05-237), and c) felsic veins ~5 cm in thickness (Pt 06-74). 11  predominantly felsic clasts are ~2-15 cm in length set in a light grey to white matrix made up of fine sand-sized to coarse sand-sized clasts. Occasionally, felsic veins ~5 cm in thickness run through the unit (Figure 2-5c; Pt 06-74). This subunit is estimated to be ~60 m in thickness (Verley et al, 2007). The main meta-conglomerate units strike southwesterly and dip on average 43˚ to the north-northwest. Foliations trend south and plunge ~40˚ to the west. Along its southern edge, the main meta-conglomerate unit grades into metasandstone and meta-argillites. At field Point Pit 9, the S1C meta-conglomerate subunit grades into meta-argillite (Figure 2-6a). The pale tan meta-conglomerate is in a conformable contact with the meta-argillite. In some areas (within this outcrop), the contact is sharp and distinct, while in other places more diffuse over ~10 cm (Figure 26b). A zone of rusty alteration, mostly likely due to weathering, exists at the contact, more noticeable on the meta-conglomerate side (Figure 2-6). Another conformable contact is visible along the southern edges of the S1CO (“other”) meta-conglomerate subunit. At field Point 05-237, the meta-conglomerate grades into meta-sandstone (Figure 2-7; Pt 05-237). The transition is visible by the distinct colour difference; the meta-conglomerate is dark brown and the meta-sandstone is light tan in colour with smaller clasts (more details in the next section). The contact is weakly diffuse over ~3 cm. Further southwest ~5 km (Figure 2-2), the main meta-conglomerate interfingers with the southwesterly striking secondary meta-conglomerate, which is part of the Doré Formation. Dips of these beds are steep, ~60˚ to the northwest. A contact between these two was not observed in the field, but is inferred by data supported by literature (i.e. Rice and Donaldson, 1992; McGill, 1992). While the diamondiferous meta-conglomerate contains smaller felsic clasts, irregular degrees of elongation to its clasts, and displays less well-defined bedding planes, this barren meta-conglomerate unit is grey, matrix supported (Figure 2-8a-c; Pt Doré 13), and contains large rounded boulders (up to 40 cm in size) of mostly granitic composition, which are all stretched at approximately the same degree (Figure 2-8). There are very few mafic clasts present, but clasts of schist, gneiss, rhyolite, granite, and tuffs are visible (Figure 2-8c; Pt 15). Bedding (2-10 cm thick beds) 12  a  meta-conglomerate  meta-argillite  b  meta-conglomerate  meta-argillite Figure 2-6 Field photographs displaying the a) transition of the diamondiferous of meta-conglomerate into bedded meta-argillite and b) the contact between the two (Pt 9).  13  meta-sandstone  meta-conglomerate Figure 2-7 Field photograph of the SC1 meta-conglomerate grading into metasandstone (Pt 05-237).  14  a granite`  S  b  c gneiss  N tuff rhyolite`  Figure 2-8 Field photographs of the barren meta-conglomerate found southwest in relation to the diamondiferous meta-conglomerate displaying a) matrix supported texture (Pt Doré 13), b) protruding mostly felsic clasts with similar degrees of stretching (Pt Doré 13) and c) different clast types such as gneiss, rhyolite, etc (Point 15-1). 15  is observable by visible sharp contacts between planar bedding (Figure 2-8a-c). The clasts protrude out of the beds. A northern occurrence of a meta-conglomerate was observed in the field, as well, but is also barren. All meta-conglomerate units described above are located to the west of the Mildred Lake Fault that trends northwest to southeast. Meta-sedimentary units are found to the east to this fault. Although a few meta-conglomerate boulders are visible, displaying small clasts (~1-2 cm in size), no corresponding outcrop was found nearby since only igneous rocks were present in the immediate area. Thus these boulders were not considered to be evidence of a continuation of main meta-conglomerate from the west. Outcrops of a meta-breccia or meta-conglomerate were seen; these outcrops were unusual as both contain subrounded and angular clasts (Figure 2-9a, b; Pt 30). These outcrops were dark brown, clast to matrix supported (Figure 2-9c), with clasts ~2-8 cm in size of varying compositions. Felsic and mafic clasts were both present, but felsic clasts dominate. A boulder of pillow basalt was noted as well, indicating a relationship with similar meta-basalts found to the west of the fault (Figure 2-9d). Other than angular clasts present, this eastern meta-conglomerate is analogous to the main metaconglomerate found to the west of the fault. 2.1.1.2 Other rocks Non-conglomeritic rocks are also seen in the field, including meta-sedimentary rocks (e.g. meta-argillites, meta-sandstones) and meta-volcanic rocks (e.g. meta-gabbro, meta-peridotite, meta-andesite, and meta-basalt). With the exception of the meta-basalt, all other volcanic rocks listed above are found as clasts within the meta-conglomerate. Several cross cutting dykes are present as well. As described above, the main meta-conglomerate occasionally grades into metaargillite. The meta-argillite consists of deformed and alternating black and grey finegrained beds (~1-5 cm in thickness) (Figure 2-10a; Pt 2). The meta-argillite shows no cross bedding, but deformation is occasionally manifested as bent planar bedding (Figure 2-10b). The meta-argillite beds range from 1-5 cm in thickness and are planar. In other areas, the meta-conglomerate grades in meta-sandstone, which can contain large (~10-40 cm in size) lenses of meta-conglomerate and meta-argillite (Figure 2-10c; Pt 05-37).  16  a  b granitic mafic  c  Figure 2-9 Photographs of the diamondiferous meta-conglomerate found east of the Mildred Lake Fault (offset by ~2 km): a) outcrop displaying both angular (pointed by blue pen) and rounded (pointed by black pen) clasts, and b) an outcrop displaying rounded granitic and mafic volcanic clasts, c) float boulder of pillow basalts. 17  a  b  c  d  Figure 2-10 Field photographs of intercalated meta-sandstones and meta-argillites. a) The meta-sandstone is cross-bedded (Pt 2). The meta-argillite displays thinly black and grey planar bedding which are b) sometimes deformed (Pt 2). Lenses of meta-argillite c) are entrained within a gradation zone between the meta-conglomerate and metasandstones/argillites (Pt 05-237). Reverse grading d) is visible in meta-sandstone beds (Pt 2).  18  Meta-argillites are sometimes intercalated with meta-sandstones as observed at Point 3. The meta-sandstones are 5-10 cm in thickness and display cross bedding (Figure 2-10a, b). Beds are observed to display reverse grading, over 5-10 cm (Figure 2-10d; Pt 05237). Verley et al (2007) estimates the package of meta-argillite/sandstone beds is at least 100 m in thickness. These beds have a southerly strike and dip on average 30˚ to the west. The meta-gabbro sample was taken from Point 229 (Figure 2-4f), extracted from an outcrop of S1C meta-conglomerate. The gabbro clasts were boulders ~10x15 cm in size (and up to 25 cm in length), subrounded and set within the tan finer grained matrix amongst other clasts (e.g. mafic and felsic volcanic). The clasts were light green and white in colour with small dark green/black (~5x2 mm) porphyroblasts of evenly distributed throughout. Underlying the main meta-conglomerate is a meta-basaltic unit. This unit actually consists of mostly volcanic sequences with occasional meta-sedimentary units, but collectively referred to as meta-basalts by this author. The meta-basalt is pale green to pale grey to tan, occasionally pillowed and fine-grained (Figures 2-3, 2-11a; Pt 6). The pillows observed are large (~100x50 cm) and elongate, with a thin ~2-4 cm rind surrounding each pillow. A contact of the meta-conglomerate with an occasional metasedimentary bed within the meta-basalts is observed as well. The dark grey metasediments grade into meta-conglomerate over a diffuse contact. The meta-sandstone contains large (~20 cm in size) irregular boudinages composed of meta-argillite, distinguished by their visible alternating light and dark bedding (Figure 2-11b; Pt 10). This older meta-volcanic (with occasional meta-sediments) is of unknown thickness, but is estimated to be at least 66 m (Verley et al, 2007). The meta-peridotite sample is ~10x10 cm in size, coarse grained, and dark green with a vitreous texture due to large flakes of biotite visible in occasional patches along the surface (no photograph available). This sample was collected as a clast and not seen in outcrops. Meta-andesite was collected as part of a drill core and thus not seen in situ. Its classification was derived by petrographic analysis. 19  a  b  Figure 2-11 Field photographs of a) meta-basalts displaying pillowed texture (Pt 6) and b) irregular meta-argillite boudinages present within a transition between meta-conglomerate and an occasional meta-sedimentary bed occurring within the meta-basaltic unit (Pt 10).  20  Three dykes are observed in the field. The first is a post-metamorphic diabase mafic dyke that crosscut the main meta-conglomerate (Figure 2-12a; Pt 110) at Point MBP 110. This dyke is dark grey, fine-grained, and ~5 m in thickness. Its texture (Figure 2-12b) is visible along a fresh surface: small white laths (~2 mm in length) are evenly distributed within and form a crisscrossing pattern set in the surrounding grey green minerals. This dyke is speculated to be part of either the Matachewan diabase dyke swarm (2454 Ma) or the Keewenawan dyke swarm (1142 Ma; Verley, 2006 and references therein). The other dykes are pre-metamorphic, indicated by replaced phenocrysts and foliation present. Two of these crosscut the main meta-conglomerate unit. One is referred to as plagioclase rich subvolcanic dyke, which is dark grey in colour, with vitreous euhedral porphyroblasts ~1x1 mm in size (located at 5326175N 671309E). The dyke is ~15 cm wide and seems to be sheared by metamorphism (no photograph available of this dyke in situ). A plagioclase-poor mafic subvolcanic dyke crosscuts meta-sedimentary units to the north of the main meta-conglomerate. It is coarse grained and dark grey with a green sheen along its surface. Intermediate-felsic meta-volcanics are found in proximity to the barren metaconglomerate. No contact was seen in the field. The northern outcrops (Pt 33) are light grey to brown ash tuffs (Figure 2-13a). Clasts are 2-3 cm in size (up to ~40-50 cm in length), elongated, and are felsic with fine grained textures (Figure 2-13a, b). In addition, flattened infilled vesicles and lapilli are present (Figure 2-13c-e). As outcrops continue southward (Pts 33-4, 32), the ash tuff transitions into tuff breccia, displaying darker brown matrix and larger clasts ~6-7 cm in length (Figure 2-13f; Pt 33-4). The colour of clasts is usually grey, with lesser amounts of pink clasts compared the previous ash tuff. Clasts also exhibit quartz porphyritic textures (Figure 2-13g; Pt 33-4). Foliation trends to the east and plunges 55˚ to the north. Mafic-intermediate meta-volcanics are visible further south, Point 32. This outcrop displays a transition from meta-sandstone to metabreccia to metamorphosed mafic flow (Figure 2-14a; Pt 32). The meta-sandstone is grey brown and massive (Figure 2-14b). Its transition into meta-breccia is diffuse and shows a change of texture into a grey and tan matrix-supported mafic meta-breccia, containing intermediate clasts (Figure 2-14c) that are elongated, ~5-10 cm in length. The matrix of this meta-breccia is dark grey with sand sized particles. Another diffuse contact is seen  21  a  b  Figure 2-12 Mafic dyke that a) crosscuts the diamondiferous meta-conglomerate, displaying its b) dark grey, fine grained, unfoliated texture (Pt 110).  22  a  b  c  d  e  f  g  Figure 2-13 Field photographs of meta-volcanics observed in the field. Pt 33 shows an outcrop of a felsic ash tuff displaying a-b) elongated felsic clasts with fine grained textures and c) flattened infilled vesicles and d-e) flattened lapilli.Pt 34-4 displays f) darker matrix with larger clasts and g) felsic clasts (examination with magnifier reveals quartz porphyritic textures). 23  a  MB MF  MS  b  c  d  NE  Figure 2-14 Field photographs of Pt 32 that displays a) transitions from meta-sandstone (MS) to meta-breccia (MB) to meta-volcanics (mafic flow; MF). The meta-sandstone is b) grey-brown and massive. The meta-breccia c) contains cobble sized clasts of intermediate composition. The mafic flow is d) massive with occasional intermediate clasts.  24  between the meta-breccia into a dark grey fine-grained mafic flow. This flow is massive with occasional intermediate clasts (Figure 2-14d). No sample taken. Detailed field descriptions along with coordinates, structural orientations, and reference photographs are presented in Appendix A. 2.1.2 Petrography: optical and SEM All petrography was performed at the Department of Earth and Ocean Sciences, University of British Columbia, Canada. Optical petrography was performed on a research grade Mecatron Precision Leica polarizing microscope mounted with a Nikon camera attachment. Scanning electron microscope (SEM) petrography was performed with a Philips XL 30 electron microscope with a Bruker Quanta 200 energy-dispersion X-ray microanalysis system and an Xflash 4010 SDD detector. All images are backscatter electron images set with an accelerating voltage of 15 kV and a beam spot size 6.0 µm. 2.1.2.1 Meta-conglomerate The Wawa meta-conglomerate ranges from being massive to bedded and sorted and the entire unit has undergone metamorphism in the greenschist facies. This polymictic meta-conglomerate comprises of 20-70% matrix and 30-80% clasts of varying compositions. These clasts, with sizes ranging from <1 cm up to 10-15 cm in length, are contained within an inequigranular matrix consisting of fine grained minerals with albite, calcite, and chlorite dominating, ± quartz, ± muscovite, ± rutile, ± epidote, ± Fe-sulfide. None of the minerals that make up the matrix exceed ~0.3 mm, but the majority of the matrix appears as finer (≤ 0.1mm) grains of the minerals listed above. The unit varies from clast supported to matrix supported throughout the entire sequence. Sedimentary features observed within the meta-conglomerate thin sections include bedding (Figure 2-15a) and juxtapositions of domains with distinct matrix compositions (Figure 2-15b). Thin section (TS) 4 contains a mafic bed ~10 mm in thickness with a clastic texture. The clasts are composed of fine-grained aggregates of plagioclase and quartz and aggregates of calcite with occasional single crystals of plagioclase contained in a bedding matrix of aligned muscovite with more calcite and 25  b  a  c  3.5 cm  17.4 mm  d  3.5 cm  8.7 mm  Figure 2-15 Plain (and one cross) polarized light photographs of thin sections displaying a) bedding, distinguishable by different modal mineralogy. Opaque minerals are oriented paralled to bedding; b) distinct matrix compositions within the same thin section (crossed polars). The more mafic composition seen along the upper portion of the field of view with the more felsic composition along the bottom; and c) soft deformation visible on a darker clast within the meta-conglomerate with a less resilient composition than those around it. FOV length is indicated.  26  chlorite. Thin section 43 displays a distinct boundary where one side of the thin section is more mafic in composition, being oxide-rich and darker in colour, while the other is distinctly more felsic (Figure 2-15b). The interfingering relationship of these sides together suggests this is a syn-depositional occurrence. In addition, soft deformation of some clasts is visible where other clasts of hardier compositions are seen impinging onto the boundaries of the others of lesser strength (Figure 2-15c). Metamorphic features observed in the meta-conglomerate thin sections include foliation (Figure 2-16a), elongate shapes and pressure shadows (Figure 2-16b, c) replacement textures and/or pseudomorphs (Figure 2-16d). Soft deformation is also observed amongst the clasts, but it is unclear if the cause is metamorphic in nature. All meta-conglomerates show hypidioblastic texture that is controlled by foliation of the euhedral platy minerals chlorite and muscovite, interspersed with anhedral quartz and plagioclase (Figure 2-16a). Metamorphic features of the meta-conglomerate are visible in field outcrops as well, such as elongate and stretched clasts. Fine-grained quartz veins (~0.4-2 mm in thickness) with infrequent crystals of calcite occur in several thin sections. Their relationship to the deformation of the meta-conglomerate has yet to be determined as either synmetamorphic or post-metamorphic. The meta-conglomerate contains clasts of varying compositions and origins from intrusive igneous (granite) to extrusive igneous (basalt) to cherts. Using optical microscopy, different polymineralic clast types in thin section were classified into the following groups: igneous with subophitic texture; coarse-grained felsic; vesicular igneous; porphyritic mafic; porphyritic felsic; untextured volcanic; chert-like; unidentifiable clasts rich in chlorite and opaques; (Table 2-1). These groups consist of 24 clast types arbitrarily numbered 1-24 (Figure 2-17 to 2-22). Gneissic clasts are not seen in thin section. As listed before, the clasts exhibit hallmarks of metamorphism including rounded elongate shapes, stretching, pressure shadows, replacement textures and/or pseudomorphs (Figure 2-16a-d). Sizes of clasts in thin section range from 1 x 0.75 mm up to 17+ mm, with an average of size of ~6 x 3 mm. There is no group of clasts that is consistently small or large; each group spans the range of sizes. All clasts display hypidioblastic textures. Metamorphic mineralogy of the clasts is typical of the 27  b  a  c  d  4.35 mm  4.35 mm  3.5 cm  4.35 mm  Figure 2-16 Thin section micrographs of a) foliation visible in the meta-conglomerate in cross polarized light. Note the aligning of platy minerals; b) elongate mafic clasts within the meta-conglomerate in plane polarized light; c) a rounded quartz grain within the metaconglomerate displaying pressure shadows; and d) a porphyritic mafic clast within the meta-conglomerate in plane (left) and cross (right) polarized light. The former phenocrysts have been replaced, displayed best in the cross polarized photo. FOV length indicated.  28  Table 2-1 Reference table with description of clasts present in the meta-conglomerate with regards to type, abundance, its reconstructed rock type, photograph reference, and evidence for its reconstruction. Reconstructed rock Abundance type Group: Igneous with subophitic texture  1  +  mafic hypabyssal clast with subophitic texture  Plate 1a  mafic effusive clast with subophitic texture  Plate 1b  2 Group: Coarse-grained felsic  3  -  4 -Group: Vesicular igneous  5  --  Reference Figure 2-17  Evidence for reconstruction  The subophitic texture indicates an igneous origin for this clast. The hypabyssal nature is manifested in the size of the plagioclase crystals ( ~0.8x0.3 mm in size); the euhedral plagioclase laths are positioned 60/120˚ to each other. Presence of epidote indicates metamorphism of a mafic mineral (most likely pyroxene) coupled with the presence of plagioclase indicates its mafic composition. Ubiquitous ultra-fine black opaque minerals (e.g. titanite) causes clast to look very dark and is possibly an alteration mineral of olivine. The subophitic texture indicates an igneous origin for this clast. The hypabyssal nature is manifested in the size of the plagioclase crystals ( ~0.2x0.01 mm in size); the euhedral plagioclase laths are positioned 60/120˚ to each other. Presence of epidote indicates metamorphism of a mafic mineral (most likely pyroxene) coupled with the presence of plagioclase indicates its mafic composition. Ubiquitous ultra-fine black opaques (e.g. titanite) causes clast to look very dark and is possibly an alteration mineral of olivine.  granite clast  Plate 1c  hypabyssal felsic clast  Plate 1d  The phaneritic texture of this clast indicates its igneous origin; the plutonic nature is evident by the size of the crystals (~2-3 mm). The clast is made up of some quartz, but mostly orthoclase, andesine, and albite, illustrating its felsic composition. This clast displays porphyritic texture, indicating its origin is igneous. The hypabyssal nature of the clast is displayed by the large resorbed phenocrysts of plagioclase ranging from 0.2 -1.0 mm in length. The plagioclase phenocrysts display both simple and polysythetic twinning. The phenocrysts make up ~10% of the clast, while the rest is fine-grained plagioclase or quartz (i.e. most minerals in this clast are felsic). A small (~1%) of fibrous chlorite is present in anhedral masses and assumed to be an alteration of an unidentifiable mineral.  Plate 2a  The porphyritic texture indicates this clast was igneous in origin. The presence of fine-grained oxides and vesicles indicates its volcanic nature. The phenocrysts (~0.4-0.8 mm in length) occur as subhedral laths while the vesicles are completely infilled by finer-grained plagioclase/quartz. The matrix is also composed of fine-grained plagioclase/quartz. The few enclaves (~4-6 mm) are anhedral with curvilinear forms and are distinguished from the host vesicular volcanic rock by the presence of fine-grained chlorite indicating its original mafic mineralogy and the smaller percentage of oxides. The enclaves also contain twinned plagioclase phenocrysts which occasionally protrude out from the confines of the mafic enclave.  vesicular clast with mafic enclaves  29  Reconstructed rock Abundance type Group: Porphyritic mafic  Reference Figure 2-17  6  --  porphyritic mafic clast  Plate 2b  7  --  porphyritic mafic intrusive clast  Plate 2c  porphyritic mafic 8 -extrusive clast Group: Porphyritic felsic  Plate 2d  9  -  10  -  porphyritic felsic hypabyssal clast porphyritic clast with plagioclase displaying perthitic texture  11  -  porphyritic felsic volcanic clast  Plate 3b  12  ++  felsic volcaniclastic clast  Plate 3d  Plate 3a  Plate 3c  Evidence for reconstruction  The porphyritic texture indicates an igneous origin for this clast. Preservation of original porphyritic texture and original phenocrysts pseudomorphed by muscovite (?). The original mafic composition is only evident by the alteration of most likely olivine or pyroxene or amphibole due to the replacement by muscovite. The clast also appears dark because of the amount of fine-grained opaques present. The coarse-grained texture of this clast indicates an igneous intrusive source. There are large elongated plagioclase crystals (~0.2x0.05 mm) with broken and rounded anhedral shapes set in a matrix now completely replaced by chlorite. The rounded anhedral shapes could be evidence of magma resorption. The replacement of the original mineral by the chlorite suggests it was originally mafic. The porphyritic texture is indicative of an igneous origin. The phenocrysts are difficult to distinguish, but have been replaced by calcite in a groundmass of albite, apatite, and Fe-sulfide. This clast is extremely dark due to the amount of fine-grained opaques present, also indicating a extrusive nature. Its porphyritic texture indicates an igneous origin. The composition of the clast is felsic with large irregularly-shaped and poikilitic plagioclase phenocrysts (~1-2 mm in length) set in a matrix of more smaller grained plagioclase showing simple twins. There is no evidence of original mafic minerals, although there are fine-grained oxides present indicating a volcanic origin, possibly hypabyssal due to the large crystal sizes of the phenocrysts. The porphyritic texture indicates an igneous origin for the clast. There are resorbed plagioclase and quartz phenocrysts, (~2-3 mm) some plagioclase crystals display perthitic textures. The matrix is made up of fine-grained plagioclase or quartz with some carbonate. The carbonate could have replaced microphenocrysts. The interlocking texture and microporphyritic texture of this clast indicates its igneous origin. The powder-like appearance of the opaques shows a typical texture associated with volcanic rocks. Its clastic texture with the presence of Ti-rich minerals (e.g. rutile) indicates its igneous origin. The mostly felsic composition of the groundmass is irregularly distributed and it is difficult to distinguish different minerals. The quartz and albite crystals are ~0.4 mm in size and rounded. Fine-grained opaques form euhedral shapes and are speculated to be former biotite crystals.  30  Reconstructed rock Abundance type  13  --  porphyritic granitoid clast  14 ++ porphyritic rhyolite Group: Untextured volcanic  Plate 4a  Plate 4b  Evidence for reconstruction  The coarse-grained and interlocking texture of this clast indicates its igneous origin. Large crystals of simply twinned subhedral laths of plagioclase and rounded quartz grains at random orientations make up ~10% of the clast, while fine-grained plagioclase or quartz makes up the rest of the clast. The porphyritic texture indicates this clast was igneous in origin. All minerals are of felsic mineralogy (quartz and plagioclase). Phenocrysts are made of subhedral quartz grains, displaying slightly rounded resorbed shapes. Its fine-grained texture and composition indicate it is a rhyolite.  -  mafic extrusive clast aphanitic mafic volcanic clast with aggregates of oxides  Plate 4d  ++  aphanitic extrusive felsic clast  Plate 5a  cryptocrystalline felsic volcanic clast  Plate 5b  The dark oxide-rich texture indicates an igneous origin for the clast. A few larger crystals of plagioclase crystals occur in laths and equant shapes (~0.2 mm in length) set in a now completely replaced matrix of chlorite. The presence of plagioclase and now replaced magnesium silicate mineral indicates its mafic composition.The dark colour of the clast is attributed to the large amount of oxides present, indicating it is extrusive. The amount of oxides present indicate a volcanic origin. There is no distinguishable texture, except for the random aggregates of oxide minerals, possibly hematite (?) due to the amorphous form and slight red birefringence. It displays soft deformation from other clasts nearby, but whether it is primary or secondary deformation is undetemined. The oxide-rich and aphanitic texture indicates an igneous origin for this clast, more specifically an effusive origin. The clasts are large (average size 8x3 mm) and elongate, with a concentration of opaque minerals at the edges distinguishing its boundaries. The presence of chlorite replacing some of the original mineralogy indicates its original mafic composition. This clast also displays soft deformation at edges possibly implying it was deposited while still heated. Clast (~4x2 mm in size) made up mostly of fine grained plagioclase/quartz and ~5% chlorite flakes. A grey mineral occurring in masses and lenses is present and completely dark in XPL. SEM microscopy indicates it is quartz. The entire clast is mostly quartz and calcite, with a small amount of chlorite, presumed to be metamorphic in origin. Its felsic mineralogy, dark appearance, and fine-grained texture indicates its igneous origin.  Plate 5c  This clast is clearly sedimentary due to the interlocking quartz/plagioclase microcrystals (~0.100.25 mm in size). In this category, there are several types of chert distinguished from each other by grain size. There are fine-grained chert clasts, medium-grained chert clasts, and coarsegrained chert clasts within these samples. The grain size refers to the size relative to other chert samples in this study. These cherts are unlikely to have an organic origin as no distinguishing replacement textures are seen.  15  --  16  17  18 -Group: Chert-like  19  Reference Figure 2-17  +  chert  Plate 4c  31  Reconstructed rock Abundance type  Reference Figure 2-17  20 carbonate-rich chert Plate 5d Group: Unidentifiable clasts rich in chlorite, and opaques 21  ++  globular ultramafic clast encompassing plagioclase laths  22  --  oxide-rich volcanic clast  Plate 6b  23  -  ultramafic clast with globular epidote  Plate 6c  Plate 6a  microporphyritic 24 -ultramafic clast Group: Monominerallic clast types mmC 1 -mafic mineral? mmC 2 -former garnet?  mmC 3  +  plagioclase and quartz grains  Plate 6d Plate 7a Plate 7b  Plate 7c  Evidence for reconstruction  This is clast is sedimentary because of its texture of interlocking quartz microcrystals (~0.8 mm in size). There are also single carbonate crystals (~0.2 mm in size) up to 20% of clast. Carbonate is unknown in regards to primary or secondary mineralogy. Complete replacement of clast by fibrous chlorite indicating replacement of a magnesium silciate (i.e. olivine, pyroxene, amphibole). The presence of plagioclase laths indicate an igneous origin. The amount of oxides present indicate an extrusive origin. This small (~0.08 mm in length) lenticular oxide-rich clast displays soft deformation from other clasts in the conglomerate. The oxide-rich texture of the clast makes mineralogical classification difficult. Elongate and lenticular forms of clast, completely replaced by chlorite. This alteration suggests replacement of a magnesium silciate (i.e. olivine, pyroxene, amphibole). A few opaques are present (1%). No other distinguishing features visible. This clast displays weak porphyritic texture, indicating an igneous origin. The ultramafic composition is implied by the complete replacement of the original groundmass of the clast by fibrous chlorite. The presence of rutile also supports the ultramafic composition. No remnant texture of the groundmass can be distinguished, making its original mineralogy unknown. The microphenocrysts are now aggregates of muscovite and retain broken shapes with a jigsaw fit texture. There are occasional laths of pleiochroic green/brown biotite as well. These chloritized clasts are stretched and almost disaggregated; they also display some soft deformation at the boundaries of the clast. This replaced clast is now completely an aggregate of muscovite(?). The replaced garnet(?) is now completely replaced of amphibole laths in a radiating structure. Because of their resilience to weathering (in comparison with more mafic minerals), these grains are not replacements and are primary occurences. The plagioclase grains sometimes display polysynthetic twinning, but are mostly simply twinned or untwinned. The quartz grains are confirmed uniaxial and occur less frequently than the grains of untwinned plagioclase. All the grains are presumed to be disaggregated from other rock types seen in this sample set. The rounded (resorbed) plagioclase and quartz grains are disaggregated from porphyritic clasts (ex: the porphyritic rhyolite) and the anhedral plagioclase and quartz with jig-saw fit outlines have disaggregated from the granites in the area. This clast is composed entirely of opaque minerals and accessory rutile. There are tails that extend out in opposite directions of the clast indicating its syn-metamorphic growth. Its original mineralogy is unknown.  mmC 4 -ultramafic clast (?) Plate 7d -- : lowest abundance; - : low abundance; + : relative abundance; ++ : very abundant; n/a : not applicable  32  a  b c d  4.35 mm  8.7 mm  8.7 mm  8.7 mm  Figure 2-17 Photographs displaying meta-conglomerate clasts. Plane polarized light to the left and cross polarized light to the right. a) mafic hypabyssal clast with subophitic texture; b) mafic effusive clast with subophitic texture; c) granite clast; d) hypabyssal felsic clast. FOV length is indicated. 33  a  b c d  8.7 mm  4.35 mm  8.7 mm  4.35 mm  Figure 2-18 Meta-conglomerate clasts. Plane polarized light left and cross polarized light right. a) vesicular clast with mafic enclaves; b) porphyritic mafic clast; c) porphyritic mafic intrusive clast; d) porphyritic mafic extrusive clast. FOV length indicated. 34  a  b c d  4.35 mm  8.7 mm  4.35 mm  4.35 mm  Figure 2-19 Meta-conglomerate clasts. Plane polarized light left and cross polarized light right. a) porphyritic felsic hypabyssal clast; b) porphyritic clast with plagioclase displaying perthitic texture; c) porphyritic felsic volcanic clast; d) felsic volcaniclastic clast. FOV length is indicated.  35  a  b c d  8.7 mm  8.7 mm  8.7 mm  4.35 mm  Figure 2-20 Meta-conglomerate clasts. Plane polarized light left and cross polarized light right. a) porphyritic granitoid clast; b) porphyritic rhyolite; c) mafic extrusive clast; d) aphanitic mafic volcanic clast with aggregates of oxides. FOV length is indicated.  36  a  b c d  8.7 mm  8.7 mm  8.7 mm  4.35 mm  Figure 2-21 Meta-conglomerate clasts. Plane polarized light left and cross polarized light right. a) aphanitic extrusive mafic clast; b) chert; c) carbonate-rich chert; d) globular ultramafic clast encompassing plagioclase laths. FOV length is indicated. 37  a  b c d  4.35 mm  4.35 mm  4.35 mm  8.7 mm  Figure 2-22 Meta-conglomerate clasts. Plane polarized light left and cross polarized light right. a) globular ultra-mafic clast encompassing plagioclase laths; b) oxide-rich volcanic clast; c) ultra-mafic clast with globular epidote; d) microporphyritic ultra-mafic clast. FOV length is indicated. 38  greenschist facies (Klein and Dutrow, 2007): albite, chlorite, ± quartz, ± calcite, ± apatite, ± rutile, ± muscovite, ± Fe-sulfide, and ± titanite (confirmed by SEM microscopy, Figures 2-23 to 2-28). In addition, four different monomineralic clasts are identified as well (Figure 229). Monomineralic clast (mmC) types 1, 2, and 4 are made up of flakes of mica (type 1), a radiating structure of amphibole laths (type 2), and a dark replaced mafic clast of opaques and rutile (type 4), correspondingly. Monomineralic clast type 3 is subdivided into two minerals: untwinned or twinned plagioclase (3a) and quartz (3b), as they commonly occur together in the same thin section, but not necessarily in contact with each other. Monomineralic clast type 3 appears consistently in the thin sections while the other three have only appeared once. All four types of mmC are sub-angular to rounded, ~1 x 1 mm in size, and display oscillatory extinction and occasionally bent twinning (when applicable). All single mmC types are interpreted to be replacements of former single grains of minerals (of which the original mineralogy is unknown), with the exception of mmC type 3. It is speculated to be disaggregated from either nearby granite clasts because of the angular shapes of plagioclase and quartz with jigsaw fit texture, lack of rounding, and unweathered character of the plagioclase or nearby rhyolite clasts (which contain rounded quartz phenocrysts), depending on their shape. 2.1.2.2 Other rocks Other non-conglomerate rocks associated with the meta-conglomerate include meta-sedimentary rocks (meta-argillites, meta-siltstones, meta-sandstones) and metaigneous rocks (meta-gabbro, meta-peridotite, meta-pillow basalt, meta-andesite, and metamorphosed mafic hypabyssal dykes). These are all described below in detail. The meta-argillites are thinly bedded (6-8 mm in thickness) which can be discerned by features such as thin black opaque lines that traverse the thin section or compositional changes between the beds (i.e. TS 50; Figure 2-30a, b). Cross bedding is visible as well (TS 2) in addition to grading within a single bed. Idioblastic foliation is observed in the argillites due to metamorphism and manifested as alignment of the platy minerals muscovite and chlorite. The foliation is observed to be at a ~45-60˚ angle in regards to original bedding. Two different bedding types are observed in thin section  39  albite chlorite calcite sphene  albite chlorite  Fe-sulfide and apatite  500 µm  Figure 2-23 SEM photomicrograph (BSE image) of clast type 1 (mafic hypabyssal clast with subophitic texture) found within the meta-conglomerate. Black and dark areas are epoxy filled pits within thin section or marker.  40  a  clast 4  500 µm  b  chlorite quartz  100 µm  Figure 2-24 SEM photomicrograph (BSE image) of clast type 19 (chert). a) Overall texture photo and b) the same clast at higher magnification. Black and dark areas are epoxy filled pits within the thin section and marker.  41  a  albite  vesicle  quartz  enclave  quartz  calcite albite  calcite Fe-sulfide  b  500 µm  apatite chlorite  albite  albite chlorite  quartz  100 µm  Figure 2-25 SEM photomicrograph (BSE image) of a) texture within clast type 5 (vesicular clast with mafic enclaves) and b) a close-up of the enclave mineralogy.Vesicles are infilled with mostly quartz with some calcite at the outer edges.  42  a calcite  albite 500 µm  b  albite  Fe-sulfide calcite  calcite  albite  apatite 100 µm  Figure 2-26 SEM photomicrographs (BSE image) of texture of clast type 8 (porphyritic mafic intrusive clast) found within the meta-conglomerate. a) Texture of clast; b) Higher magnification of the same clast. Black and dark areas are epoxy filled pits within thin section or marker.  43  a rutile muscovite calcite  chlorite albite 500 µm  b  quartz  rutile  albite  chlorite apatite matrix  500 µm  Figure 2-27 SEM photomicrographs (BSE image) of texture seen in meta-conglomerate a) matrix and b) clast type 12: felsic volcaniclastic clast in thin section. Black irregular shapes are epoxy filled pits within the thin section.  44  a  clast type 20  matrix  chlorite  calcite  muscovite chlorite  quartz  rutile  apatite  Fe- sulfide clast type 17  b  quartz  chlorite  clast type 4  calcite albite  quartz  500 µm  quartz  calcite apatite  chlorite  chlorite  quartz phenocryst quartz  quartz phenocryst  calcite 500 µm  Figure 2-28 SEM photomicrographs (BSE image) of meta-conglomerate displaying four different clasts and their boundaries with matrix. The clast names are as follows: a) clast type 4 (hypabyssal felsic clast), clast type 17 (aphanitic extrusive felsic clast), and clast 20 (carbonate-rich chert) and b) clast type14 (rhyolite). Black areas are epoxy filled pits within the thin section.  45  a  b c d  4.35 mm  4.35 mm  2.17 mm  4.35 mm  Figure 2-29 Monominerallic clast types in meta-conglomerate. Plane polarized light left and cross polarized light right. a) Type 1; b) Type 2; c) Type 3; d) Type 4. FOV length is indicated. 46  b  a  c  3.5 cm  8.7 mm  bed type 1  bed type 2  500 µm  d  bed type 1 chlorite apatite  e  bed type 2 muscovite  apatite quartz  albite  100 µm  100 µm  Figure 2-30 Photomicrographs of textures of meta-argillites displaying a) thin bedding and b) cross bedding (both in plane polarized light). FOV length is indicated. SEM photomicrographs (BSE images) display c) two different types of beds with close-ups (d, e) of each type. Black areas are epoxy filled pits or marker, within the thin section.  47  (Figure 2-30c, d, e), type 1 and type 2. Type 1 bedding is cross-bedded, darker, and all minerals are homogeneously dispersed (albite, chlorite, and apatite) throughout. Type 2 bedding is horizontally planar and contains thinner beds of varying mineralogy, with calcite or muscovite dominating a bed, with quartz and apatite in lesser quantities. Mineralogy confirmed by SEM microscopy. In exposed field outcrops, a gradual transition from meta-conglomerate into metasandstones is observed. These meta-sandstones can be massive (Figure 2-31a), but are occasionally bedded (Figure 2-31b), distinguished by dark oxide-rich or organic-rich lines that cross the thin section and sometimes by varying compositions. Stylolites are observed in one sample (TS 49; Figure 2-31c), identified by its typical zig-zag saw tooth form, which could possibly indicate relative depth of metamorphism. Lithic clasts that are also present in the meta-conglomerate thin sections are seen in the meta-sandstones. Like the meta-conglomerate, the clasts make up ~40-60% of the rock, but are usually smaller (~0.1-0.8 mm) in size. The meta-sandstones also display hypidioblastic texture, foliation observed by alignment of chlorite and muscovite, and minor folding (TS 49). The metamorphic minerals that comprise the matrix include calcite, epidote, and an unknown prismatic mineral (with 1st order interference colours and straight extinction; TS 29) contained in felsic lithic clasts (i.e. granite, chert). It is evident the original sandstone used to contain larger (0.1-2 mm) lithic clasts of felsic compositions, but now all that remains are rounded aggregates of metamorphic minerals such as fine-grained quartz and chlorite. Quartz and calcite veins are sometimes present and do not exceed 0.5 mm in thickness. Meta-siltstones are similar in all aspects to the meta-sandstones except for grain size. The meta-gabbro sample analyzed displays coarse-grained equigranular idioblastic massive texture (Figure 2-32a) with metamorphic mineralogy consisting of chlorite, an unknown dark cryptocrystalline mineral (TS 45), calcite, plagioclase and quartz, muscovite, and epidote. This reconstruction of the original igneous rock type is made based on shapes and compositions of metamorphic mineral aggregates replacing original minerals. It is inferred the original rock was made of a mafic mineral and plagioclase. Fine-grained fibrous chlorite with patches of calcite (a ratio of ~9:1) has 48  a  b c  3.2 cm  3.2 cm  8.7 mm  Figure 2-31 Photomicrographs of meta-sandstones displaying both a) massive and b) bedded textures, beds distinguishable by mafic mineralogy (both in crossed polarized light). One sample displayed c) stylolites. FOV length is indicated.  49  a 3.5 cm  b  d  8.7 mm  8.7 mm  Figure 2-32 Photomicrograhs of a) the coarse-grained idioblastic texture (in plane polarized light) of the meta-gabbro in addition to dark minerals that were replaced by a cryptocrystalline mineral aggregate. Its 60/120˚ outer angles and blocky shape suggest it was once hornblende or biotite; b) a replaced elongate crystal. Due to the lath-like shape of the original crystal, most likely plagioclase which is now completely replaced by fibrous chlorite (plane polarized photo left and cross polarized light right). FOV length indicated.  50  replaced large (~3x1 mm) prismatic grains, assumed to once been plagioclase, making up ~35% of the sample (Figure 2-32a). A dark cryptocrystalline unidentified brown mineral aggregate that occurs in masses has replaced another euhedral mineral with ~60/120˚ outer angles (Figure 2-32b). Olivine and pyroxene are not likely candidates, as their mineral habits do not correspond with the remnant texture seen now, therefore it is inferred that mafic mineral could be either hornblende or biotite. This evidence, coupled with the coarse-grained nature of the rock points toward gabbro as the protolith. The meta-peridotite exhibits inequigranular porphyroblastic texture, also with pseudomorphs replacing original mineralogy (Figure 2-33a). Aggregates of fibrous chlorite has replaced the large (~2-3 mm) crystals along with some opaque minerals at a ratio of ~9:1. Despite of this replacement, distinctive cracks, elongate shapes, and ~120˚ outer angles leads to the conclusion olivine was the original mineral (Figure 2-33b). The groundmass is made up of clinopyroxene in anhedral block and elongate shapes with a variety of sizes (from 0.05x0.13 – 1.70x1.30 mm), displaying replacement by biotite and fibrous chlorite at the outer edges. Biotite also occurs interstitially in larger pleochroic brown crystals. Muscovite is also present as anhedral interstitial crystals and fine-grained aggregates associated with the chlorite. No remnant textures of plagioclase are seen, inferring only pyroxene and olivine were the original minerals and therefore this rock was a peridotite before metamorphism. The meta-andesite exhibits porphyroblastic massive texture (Figure 2-34a). No foliation is present and thus the rock is presumed to be post-deformation. Former phenocrysts are replaced by chlorite with distinctive blue/violet colours (in crossed polarized light) and spherulitic textures, retaining the shape of two large (~4x2 mm) euhedral plagioclase laths (Figure 2-34b). The former microphenocrysts are replaced by fibrous biotite and chlorite (Figure 2-34c), hosted in a groundmass consisting of more fibrous biotite, quartz, calcite, quartz, epidote, titanite, and Fe-sulfide (confirmed by SEM microscopy, Figure 2-35). The replaced micro-phenocrysts have indistinct boundaries, but are generally lath-shaped and inferred to be replaced plagioclase. Due to the large amount of replaced felsic minerals and size of the original minerals (i.e. finer grained and therefore extrusive), andesite was most likely the protolith. 51  a  b  3.0 cm  3.0 cm  8.7 mm  8.7 mm  Figure 2-33 Photomicrographs of a thin section of meta-peridotite a) displaying its inequigranular and porphyroblastic texture and b) replaced crystals. The crystal habit and distinctive cracks running through the mineral in addition to its replacement by chlorite point towards olivine as the original mineral. Plane polarized light photo left and cross polarized light photo right. FOV length indicated.  52  a  b  c  3.0 cm  3.0 cm  8.7 mm  8.7 mm  3.0 cm  3.0 cm  Figure 2-34 Photomicrographs of a thin section of meta-andesite a) displaying the general porphyroblastic texture with no foliation. The porphyroblasts are b) euhedral laths of former plagioclase now replaced by chlorite with distinctive blue anomalous interference colours and c) microphenocrysts present are also replaced by fibrous biotite and chlorite. Like the larger phenocrysts, these are generally lath shaped and presumed to once been plagioclase. Plane polarized light photo left and cross polarized photo right. FOV length indicated.  53  Fe - sulfide, epidote, and sphene biotite chlorite  biotite  calcite  quartz 1 mm  Figure 2-35 SEM photomicrograph (BSE image) of texture of meta-andesite displaying phenocrysts replaced with aggregates of chlorite and biotite (a ratio of 3:2) set in a groundmass. Black areas are epoxy filled pits within the thin section and marker.  54  The metamorphosed pillow basalt displays equigranular porphyroblastic massive texture rich in oxides (Figure 2-36a). Two types of metamorphic aggregates replace two distinct magmatic phenocrysts (confirmed by SEM microscopy; Figure 2-37a, b). Type 1 phenocrysts are observed to be fine-grained muscovite aggregates ~0.8x0.4 mm in size, elongate, and euhedral, presumed to once be plagioclase (Figure 2-36b). Type 2 phenocrysts are small prismatic aggregates of biotite and chlorite that replaced an unknown mineral (possibly olivine) (Figure 2-36c). As for the fine-grained matrix, muscovite, quartz, albite, chlorite, rutile and Fe-sulfide are present. The typical oxiderich appearance of mafic extrusive rocks coupled with the mineralogy points towards pillow basalt as the protolith. Three types of mafic hypabyssal rock are present amongst the samples, two of which are metamorphosed and one that is post-metamorphic. Field observations determine the rocks comprise dykes. Both metamorphosed dykes are comprised of subvolcanic rock with one being plagioclase-poor while the other is plagioclase-rich. The third dyke present is a diabase. The diabase dyke is the only post-metamorphic dyke because of a lack of foliation and the presence of primary mineralogy, which consists of approximately equal parts andesine and clinopyroxene (Figure 2-38a). Euhedral to subhedral opaques in blocky shapes are evenly dispersed through the thin section and small biotite laths ~0.23 mm in length have replaced ~5-10% of the clinopyroxene volume. The metamorphosed plagioclase-poor mafic subvolcanic rock is foliated and porphyroblastic (Figure 2-38b). Actinolite has mostly replaced the clinopyroxene porphyroblasts (Figure 2-38c), reconstructed by the euhedral shape and ~120˚ outer angles of the pseudomorphed crystal. In addition, small crystals of biotite, calcite, and chlorite occur with the actinolite. The groundmass consists of finer-grained (not exceeding 0.2 mm) crystals of the above minerals and rare chlorite grains. An odd aggregate of a high relief mineral showing lower interference colours (Figure 2-39a) exists in only one area of the thin section ~3.5x2 mm in size within the fine-grained matrix. This aggregate could be an altered phenocrysts or an altered xenolith. The reconstructed igneous texture of the rock is pyroxene-phyric, inequigranular, and  55  a  b  c  3.4 cm  3.4 cm  4.35 mm  4.35 mm  8.7 mm  Figure 2-36 Photomicrographs of meta-basalt with pillowed texture displaying a) equigranular massive texture with phenocrysts of b) small lath shaped replaced crystals in pillow basalt, partially replaced by fibrous mica and c) small anhedral replaced crystals (olivine?) (plane polarized light only). Plane polarized light photographs left and cross polarized light photographs right. The FOV length is indicated.  56  a  phenocryst type 1 phenocryst type 2  phenocryst type 2  chlorite  biotite  groundmass  b  chlorite albite  muscovite  200 µm  Fe-sulfide  rutile  chlorite phenocryst type 1 groundmass  quartz 100 µm  Figure 2-37 SEM photomicrograph (BSE image) of meta-basalt replaced phenocrysts set in a groundmass. a) Overall texture of both types of replaced phenocrysts, type 2 being more easily visible at that magnification. b) Close-up of replaced phenocryst type 1 and groundmass mineralogy. Black areas are epoxy filled pits within the thin section or marker.  57  a  8.7 cm  b  c  3.0 cm  3.0 cm  8.7 mm  8.7 mm  Figure 2-38 Photomicrographs of a) texture and mineralogy of a post-deformation dyke containing equal parts of andesine and clinopyroxene (only in cross polarized light) and of metamorphosed plagioclase-poor mafic subvolcanic rock displaying b) porphyroblasts made up of actinolite, most likely replacing pyroxene judging by c) outer angles showing 60/120˚ blocky shapes. Plane polarized light photos left and cross polarized photo right. FOV length indicated.  58  a  b  c  8.7 mm  8.7 mm  3.0 cm  3.0 cm  8.7 mm  8.7 mm  Figure 2-39 Photomicrographs of a) an odd aggregate of a high relief mineral showing low interference colours existing in only one area of the thin section ~3.5x2 mm in size within the fine-grained matrix. Metamorphosed plagioclase-rich subvolcanic rock displays b) inequigranular and porphyroblastic texture with c) euhedral shapes and prismatic angles indicate it could be hornblende or biotite. Plane polarized light photographs left and cross polarized light photographs right. The FOV length is indicated.  59  hypidiomorphic with large euhedral phenocrysts in a massive fine-grained matrix consisting of laths and anhedral minerals. The metamorphosed plagioclase-rich subvolcanic rock displays inequigranular, porphyroblastic and idioblastic texture (Figure 2-39b). As in another subvolcanic rock, the porphyroblasts are not monomineralic and are observed as aggregates ranging from ~0.2-0.8 mm up to 2.0x1.0 mm in size consisting of biotite, chlorite, and epidote (Figure 2-39c). The aggregates retain the euhedral shape of the original mineral, which is most likely plagioclase, but could be hornblende or biotite. The fine-grained matrix consists of biotite, plagioclase and quartz, epidote, chlorite, calcite, and opaque minerals. Judging by the amount of plagioclase and epidote (presumed to be a common alteration mineral of mafic minerals), this rock was once a diabase dyke. No samples of intermediate-felsic meta-volcanics were taken for petrographic analysis. A detailed optical and SEM petrographic description is presented in Appendix B. 2.1.3 Geochronology 2.1.3.1 Analytical methods Four samples were collected at field points 4, Doré 13, 29, and 229 and dated using TIMS U-Pb techniques on zircons. Samples were prepared at the Pacific Centre for Isotopic and Geochemical Research (PCIGR) in the department of Earth and Ocean Sciences, University of British Columbia by Richard Friedman (PCIGR Research Scientist) and lab technicians Corey Wall, Yeena Feng, and Hai Lin. Zircon grains were extracted using conventional crushing, grinding, and Wilfley table techniques followed by final concentration using heavy liquids and magnetic separations. Grain selection was based on characteristics including grain quality, size, magnetic susceptibility and morphology. Using techniques from Scoates and Friedman (2008), zircon grains were dissolved in ~75mL of 48% HF and 14 M HNO3 (ratio of ~10:1, respectively) in the presence of a mixed 233-235U-205Pb tracer. Grains were then contained in PFA or PTFE teflon microcapsules inside high pressure Parr™ acid digestion vessels with 125 mL PTFE liners for 40 hours at 240˚C. Sample solutions were then dried to salts at ~130°C. Residues were redissolved into ~50 mL of sub-boiled 6.2 M HCl for 12 hours at 210˚C. 60  After an addition of 2 mL of 0.5 N H3PO, solutions were dried into droplets, then loaded onto single, degassed zone refined Re filaments in 5 mL of a silicic acid - phosphoric acid emitter (Gerstenberger and Haase, 1997). Using a modified single collector VG-54R thermal ionization mass spectrometer (TIMS) equipped with an analogue Daly photomultiplier, isotopic ratios were measured in peak-switching mode on the Daly detector. Analytical blanks were 0.2 pg for U and up to 5 pg for Pb. U fractionation was determined using the 233-235U tracer and a corrected fractionation of 0.23%/amu was used for Pb isotopic ratios, based on replicate analyses of the NBS-982 Pb standard and recommended values (Thirlwall, 2000). Reported precisions for Pb/U and Pb/Pb dates were determined by numerically propagating all analytical uncertainties through the entire age calculation using the technique of Roddick (1987). Standard concordia diagrams were constructed and regression intercepts calculated with Isoplot 3.00 (Ludwig, 2003). Unless otherwise noted, all errors are quoted at the 2σlevel. 2.1.3.2 Geochronology of the meta-conglomerate Ages determined from TIMS U-Pb dating on zircons from collected field samples constrains the age of the diamondiferous meta-conglomerate between 2700.4±1.0 Ma and 2697.2±1.8 Ma, much older than the typical occurrences of diamond hosted in Phanerozoic-age kimberlites (e.g. Gurney et al, 2010). Granite (Pt 29) and gabbro clasts (Pt 229) in the meta-conglomerate are dated at 2700.4 ± 1.0 and 2701.0 ± 1.2 Ma, correspondingly (Figures 2-40, 2-41). The minimum limit on the meta-conglomerate age is that of a crosscutting felsic dyke (Pt 4), 2697.2 ± 1.8 Ma (Figure 2-42a). The diamondiferous meta-conglomerate thus formed between 2700 and 2697 Ma. And though it forms an interfingering relationship with barren meta-conglomerate to the southwest, a granitic clast dated from this area (Pt Doré 13) places this unit at 2693.7 ± 1.5 Ma (Figure 2-42b). The barren meta-conglomerate may be younger in age or may represent a different source. Meta-conglomerate younging direction parallels the southwestern younging direction of lamprophyric debris flows located to the north (De Stefano et al, 2006). 2.1.4 Interpretation As discussed in the previous section, the following groups of clasts were found  61  a  0.523  206  Pb/ 238U  0.522 2704  0.521  2702 2700  0.520  2698  2696  0.519  granitic clasts: 2700.4 ± 1.0 Ma  0.518 13.22  206  Pb/ 238U  b  2706  13.26  207  13.30  Pb/  MSWD = 0.86  235  U  13.38  13.34  0.525 0.523 0.521 0.519  2696  0.517 13.20  2698  2700  2702  2704  2706  2708  gabbro clasts: 2701.4 ± 1.2 Ma 13.24  13.28  207  13.32  Pb/  235  U  13.36  MSWD = 0.39  13.40  Figure 2-40 U-Pb ratios for zircon grains extracted from a) Pt 29 (granitic clasts) and b) Pt 229 (gabbro clasts). All errors are quoted at the 2σ level. Standard concordia diagrams were constructed with Isoplot 3.00 (Ludwig, 2003).  62  206  Pb/207Pb Age (Ma)  a  206  Pb/207Pb Age (Ma)  b  2704  granitic clasts: 2700.4 ± 1.0 Ma  2702  2700  2698  2696  2705  MSWD = 0.86, probability = 0.46  gabbro clasts: 2701.0 ± 1.2 Ma  2703 2701 2699 2697 2695 2693  MSWD = 0.39, probability = 0.81  Figure 2-41 Weighted averages of 207/206 Pb ratios based on zircon dating results for diamondiferous meta-conglomerate field samples a) Pts 29 (granitic clasts) and b) Pt 229 (gabbro clasts). All errors are quoted at the 2σ level. Standard concordia diagrams were constructed with Isoplot 3.00 (Ludwig, 2003). 63  a  0.52  2630  2650  2640  2660  2680  A E  B  0.50  206  Pb/ 238U  0.51  2670  2690  0.49  C  felsic dyke: 2697.2 ± 1.8 Ma 0.48 12.2  b  12.4  12.6 207  Pb/  0.53  12.8  235  U  13.0  13.2  2700  0.52  2690 2670  0.51  2630  0.50  D  0.49 0.48 12.1  E  2650  206  Pb/ 238U  MSWD = 0.027  B  12.3  12.5  granitic clast: 2693.7 ± 1.5 Ma 12.7  207  12.9  Pb/ 235U  13.1  MSWD = 1.3  13.3  13.5  Figure 2-42 U-Pb dating on zircon results for meta-conglomerate field samples for a) Pt 4 (cross cutting felsic dyke; grain B excluded because off trend) and b) Pt Doré 13 (granitic clast). All errors are quoted at the 2σ level. Standard concordia diagrams were constructed with Isoplot 3.00 (Ludwig, 2003). 64  within the meta-conglomerate: igneous with subophitic texture, coarse-grained felsic, vesicular igneous, porphyritic mafic, porphyritic felsic, untextured mafic volcanic, chertlike, and unidentifiable clasts rich in chlorite, and opaques. The three cycles that make up the Michipicoten Greenstone Belt (MGB) are named the Hawk, Wawa, and Catfish assemblages corresponding with the oldest to youngest cycles. For simplicity, these assemblages will be called Cycles 1, 2, and 3 to avoid confusion regarding their relative ages. The youngest felsic volcanics of each cycle is conjectured to be the source of most of the sedimentary rocks found within the respective cycle (Williams et al, 1991). The Wawa meta-conglomerate is within close proximity (~10 km) to several different rock types: Cycle 1 granitic stock and komatiite (2890 Ma) to the east; Cycle 2 mafic, intermediate, and felsic meta-volcanics and the synvolcanic granitoid pluton (2750 Ma) to the south; Cycle 3 mafic, intermediate, and felsic meta-volcanics to the north (2700 Ma). Although U-Pb zircon age constraints for the meta-conglomerate places its age between 2700 and 2690 Ma, it is assumed there is some contribution to the meta-conglomerate from Cycles 1 and 2, but the majority of the clasts are derived from within Cycle 3 itself. Because there are no chert units within Cycle 3, the base of Cycle 2, which contains bedded chert-magnetite-wacke (Williams et al, 1991) underlying the iron formation at the uppermost part of the unit, may have sourced the chert-like clasts seen in thin section. Cycle 3 is actually made up of an upper and a lower meta-volcanic unit. The lower portion is made up of tholeiitic flows, overlain by sediments and intermediate to felsic meta-volcanics (Williams et al, 1991). The upper meta-volcanics are mostly made up of crystals tuffs and clasts derived from these are seen in abundance (felsic tuffisitic clasts). The tholeiitic flows of the lower portion could account for the mafic effusive clasts with subophitic texture, vesicular clasts with mafic enclaves, porphyritic mafic and porphyritic mafic extrusive clasts, and possibly any of the untextured mafic volcanic rocks. In addition, Sage (1994) documents pillowed flows that are frequently vesicular, indicating another possible source for the vesicular clasts with mafic enclaves. As for any ultra-mafic rocks, presumed to be the source for the chloritized clasts, no rock units within Cycle 3 correspond. Several small peridotitic stocks intrude into Cycle 2 and 65  Cycle 1 contains units of peridotitic komatiite, which cannot be completely discounted as possible sources. The Jubilee stock, 2745 Ma, is the subvolcanic equivalent of many of the rock types making up the Cycle 2 assemblage (mostly intermediate and felsic volcanic rocks) (Williams et al, 1991; Sage, 1994). This stock is possibly the source for several types of clasts found in the meta-conglomerate: hypabyssal felsic clast, porphyritic felsic hypabyssal clast, and porphyritic granitoid clast. Granitic boulders (2696 and 2698 Ma (Williams et al and references therein, 1991) of the Cycle 3 assemblage have corresponding ages to the intermediate and felsic meta-volcanics of Cycle 2, indicating possible source rocks for any of these clasts as well. Intrusive rocks displaying porphyritic textures are found in the northern region of the MGB, ranging from trondhjemite to syenite in composition (Sage, 1994). Their ages, 2670 – 2700 Ma, encompass the meta-conglomerate’s formation and could be sources of any of the felsic porphyritic clasts found in the meta-conglomerate: porphyritic clast with plagioclase displaying perthitic texture, porphyritic felsic hypabyssal clast, and porphyritic granitoid clast.  2.2 Meta-breccia host rocks Characterization of the meta-breccia host rocks was not part of this study and all data, unless otherwise noted, is reported from literature. 2.2.1 Field observations The polymictic volcaniclastic breccia (PVB) consists of several beds that occur over several stratigraphic levels (Lefebvre et al, 2005). These units are poorly sorted and mostly massive, with angular sand to boulder-sized clasts (of mostly igneous origin) set in a greenish-grey fine grained matrix. They are occasionally bedded, rarely graded with normal grading observed and ranges between clast- and matrix-supported (Lefebvre et al, 2005). Lefebvre et al (2005) identified up to 11 different clast types present within the unit including mafic/felsic meta-volcanic rocks, intermediate/mafic intrusive rocks, clasts 66  of autoclastic clast-supported and matrix-supported breccia, juvenile magmatic material, and lithic fragments. Lamprophyre dykes that also make up the meta-breccia units are inequigranular, fine grained, and grey to black in colour. These dykes are 0.5-3 m thick in which eight different types of cobble-sized fragments are present (Lefebvre et al, 2005). Unlike the breccias, the dykes contain fewer fragments, fewer lithological clast types, and an absence of juvenile magmatic material. In addition, there is also a reduced fabric development. They are younger than the PVB as evidenced by their crosscutting relationship (Lefebvre et al, 2005). 2.2.2 Petrography Lefebvre et al (2005) reports the clasts of PVB are contained within a matrix consisting of actinolite, chlorite, albite, ±titanite, ±epidote, and ±biotite with coarse hornblende present as well. They also confirm the lamprophyre is made up of hornblende, actinolite, epidote, biotite, ±chlorite; unlike the PVB, the lamprophyres do not contain oscillatory-zoned hornblende, but does contain more biotite. This author confirms this mineralogy with her own SEM microscopy of PVB. The only discrepancy is the presence of apatite in thin section 53 and albite in thin section 54 (Appendix B). 2.2.3 Geochronology Dating of several breccia beds showed younging of their ages from 2724± 24 Ma in the northeast to 2680±1 Ma in the southwest (De Stefano et al., 2006), while dykes crosscutting the meta-breccia display ages between 2715 and 2664 Ma (Lefebvre et al, 2005). This author had a sample of lamprophyric breccia dated for comparative analyses (Pt 15-2 on Figure 2-1). This sample is even younger, 2619.1±1.8 Ma, and supports the southwestern younging trend.  2.2.4 Interpretation Calc-alkaline lamprophyre is suggested to be the primary magma of the metabreccia unit based on meta-breccia matrix, juvenile magmatic material, and lamprophyre 67  mineralogical assemblages (Lefebvre et al, 2005). This conclusion is derived from geochemistry data on various minerals in addition to whole-rock geochemistry. Mantle origin for the lamprophyres is supported by presence of diamond, mantle-derived ultramafic xenoliths, and a high contents of mantle elements (e.g. MgO, Ni, Cr, and Co) in the meta-breccia (Lefebvre et al, 2005). As reported by Lefebvre et al (2005), the polymictic volcaniclastic breccia (PVB) represents a mass-flow lahar deposit as evidenced by poor sorting, presence of pyroclastic material, preservation of delicate volcanic fragments that would normally disaggregate during reworking, and presence of several beds displaying older metabreccia fragments found within younger meta-breccia units. Calc-alkaline magmatism is coeval with cycle 3 of the Michipicoten Greenstone Belt (MGB) and suggested to be emplaced episodically in grabens in an Archean subduction zone (Lefebvre et al, 2005).  68  Chapter 3: Physical characteristics of diamonds 3.1 Morphology and colour of natural diamonds Other than a small amount of impurities present within the lattice, diamond is composed entirely of carbon atoms. Diamond is isometric. Each unit cell consists of four sets of five carbon atoms arranged in a tetrahedron, and every atom is covalently bonded to four other carbon atoms, forming a face centered cube (Figure 3-1a; Perkins, 2002). 3.1.1 Growth form The habit of diamond growth is dependent on the relationship between supersaturation of carbon in the liquid from which diamond is crystallizing and growth rate (Sunagawa, 1984b; Gurney, 1989; Figure 3-1b). Smooth faced octahedral crystals grow at a low saturation of carbon (below σ*) (Figure 3-1b). Carbon atoms have difficulty bonding to the smooth surface, lowering the rate of growth and thus the crystal grows by either spiral or layer-by-layer growth (Sunagawa, 1984a). In contrast, rough faced cuboid diamonds grow in unstable conditions, with a higher carbon supersaturation (above σ**). The growth rate is quite fast as carbon atoms are able to nucleate anywhere on the surface, resulting in fibrous textures (Sunagawa, 1984a, 1984b; Boyd et al, 1994). Cubo-octahedral “hopper” crystals with inverted faces (called “skeletal” crystals in petrography) occur at saturations between σ* and σ** (Boyd and Gurney, 1986; Sunagawa, 1984b). Morphology can reflect not only the growth conditions (Sunagawa, 1984a, 1984b), but also its subsequent post-growth history (Robinson, 1978). A diamond’s current shape can be very different from the initial growth habit, due to the variety of processes that can alter the primary form such as dissolution or mechanical abrasion (Orlov, 1977; Robinson, 1978; Sunagawa, 1984b). Below are descriptions of the basic growth habits of diamond. According to Harris (1992), most mines report that octahedral crystals make up ~20-40% of their diamond production, macles comprise of 10-20%, and polycrystalline aggregates make up ~5-10% with cubic diamonds being rare, ~1%. 69  a  b growth rate (R)  smooth faces  spiral growth  rough faces  fibrous growth  skeletal growth  0  σ** σ* supersaturation (σ)  Figure 3-1 a) Atomic structure of diamonds; arrangement of carbon atoms in unit cell. b) Schematic diagram of supersaturation vs growth rate of diamond. Below σ*, spiral growth results in smooth crystals. Between σ* and σ**, slow smooth growth also dominates, but results in skeletal texture. Above σ**, fast growth results in rough faces with fibrous and dendritic textures (modified after Sunagawa, 1984a).  70  Octahedral diamond crystals display a characteristic symmetric “diamond” outline, with pointed corners and flat faces (Figure 3-2a). Octahedral crystals grow along {111} faces, which can be smooth or exhibit other features. A common feature is a stacking of triangular plates outward from the face; these plates are a lamellar growth, forming layers where later plates are smaller than the previous one (Figure 3-2b). Stacks can grow out from the center or be displaced towards any edge or corner (Orlov, 1977). A diamond with these stacks present on the faces is referred to as having stepped faces or displaying polycentric growth. As is frequent in nature, “perfect” crystals are rare thus many octahedral crystals display some sort of distortion of the axes (Orlov, 1977; Robinson, 1978). Usually, octahedral crystals display some sort of distortion such as flattening along the (110) direction or the (010) direction (Figure 3-2c). This distortion is merely a manifestation of non-uniform development of the octahedral faces (Orlov, 1977). In this study, such crystals are classified as a flat-faced octahedron. Twinning in diamond obeys the spinel twin law; preferential growth along a shared plane of atoms results in twinned forms that are mirrors of each other. The most common is a macle that is flat and triangular, due to preferential growth along re-entrant corners (Figure 3-2d; Orlov, 1977; Robinson, 1978). According to Kitamura et al (1979), dislocations along the twinned plane act as growth sites for the twinning. Macle twins always display smooth crystal faces because their growth occurs in supersaturation conditions below σ*; same as octahedra. Otherwise, macles would display fibrous growth (Kitamura et al, 1979). Twinning can be observed in cuboids as well, but result in interpenetrating cuboid shapes. Cube shaped diamond crystals (Figure 3-2e) are less common that octahedral crystals (Robinson, 1978) and like octahedral diamonds, in nature are rarely “perfect”. The {100} faces are never smooth, due to their fibrous growth and can even be undulatory, concave, or convex and are therefore referred to as cuboid (Robinson, 1978). Cuboid diamonds also tend to trap a large amount of fluid and/or mineral microinclusions (Boyd et al, 1994). 71  (a)  (b) (111)  (d)  (c)  )a 11 (1 1)b 1 1 (  (e) (100)  (f)  (g)  (h )  Figure 3-2 Schematic diagrams of diamond primary growth forms: a) octahedron, b) octahedron with stepped faces, c) flat-faced octahedron, d) macle twin, e) cuboid, f-g) coated diamonds, and h) a bort aggregate. Twinnning growth direction is indicated by arrow. Coated diamond fibrous growth is indicated by grey hatching.  72  The occurrence of coated diamonds is not uncommon (Harris, 1992 and references therein); coated diamonds grow within an unstable and changing environment, usually resulting in a crystal with a smooth octahedral core (showing a slow stable growth rate) with a fibrous cubic-shaped coating (indicating a change into a higher carbon supersaturation and faster ‘abnormal’ growth) (Figure 3-2f) Sunagawa, 1984b). The opposite does occur, with a fibrous cuboid core and a smooth octahedral coating, but it is rare (Figure 3-2g); Rondeau, 2007). Because of their combination habits, these diamonds are labeled as displaying cubo-octahedral growth. In addition to single crystals, diamonds can form polycrystalline aggregates. These aggregates are classified separately from single crystalline diamonds and can be further subdivided by their textures (Orlov, 1977). The main polycrystalline classifications are as follows: bort: granular to cryptocrystalline aggregates of diamond (Figure 3-2h); ballas: made up of radiating structures of diamond fibrous growths; and carbonado: massive and granular aggregation in an irregular opaque lump. 3.1.2 Diamond colour A “perfect” diamond crystal will have no colour, because the energy of visible light is not enough to excite electrons across the band gap and thus no light is absorbed. Once the symmetry of the lattice is compromised by either interstitial impurities or mineral inclusions, visible light is absorbed and diamonds will display a colour depending on what type of impurity is present (Orlov, 1977; Fritsch, 1998). The most common colours in diamond are yellow and brown (Harris et al, 1975; Robinson, 1978; Harris, 1992). Although some diamond deposits are well known for their “fancy” diamond colours, such as the Argyle mine producing most of the world’s red and pink diamonds (Fritsch et al, 1998), a variety of colours can be seen within a single diamond suite. Table 3-1 is a simplified chart of the different colours in diamond and their respective causes. Colourless diamonds are a result of a crystal with very few lattice impurities (e.g. Robinson, 1978; Harris, 1987) or the presence of platelets, a displaced plane of carbon atoms created by migrating nitrogen impurities (Bruton, 1970; Clark et al, 1992). Yellow 73  Table 3-1 Explanations for colouration in diamond (after Orlov, 1977; Robinson, 1978; Fritsch, 1998; Titkov et al, 2003; Titkov et al, 2008). Colour Reason for colouration yellow  interstitial nitrogen, or more commonly, N3 centres  brown  vacancy-related defects induced by plastic deformation  black/grey opaque blue pink/mauve/red purple green  orange  micro-inclusions of graphite, magnetite, or hematite defects in the structure interstitial boron (sometimes grey as well) unknown, possibly due to lattice defects or plastic deformation concentration of inclusions along deformation induced lamellae or mechanical twinning -surface coatings: caused by irradiation -body colour: resulting from a combination of defects resulting in green reflection or 2 nitrogen + a vacancy (H3) defects unknown, possibly due to interstitial nitrogen  74  colour results from interstitial nitrogen substituting for carbon atoms in amounts as low as 30 ppm (Harris, 1987). Depending on the type of nitrogen impurity, the yellow colour can vary: three nitrogen atoms surrounding a vacancy (N3 center) causes the common straw yellow colouration, while rare single nitrogen substitutions manifests as pale yellow to amber (Orlov, 1977; Robinson, 1978). Brown colouration is due to plastic deformation of the crystal lattice most likely caused at depth, creating vacancy clusters (Harris, 1987; Smith et al, 2010). These vacancy clusters are an aggregate of perhaps ~60 vacancies (Hounsome et al, 2007; Fujita et al, 2009) along which impurities lie, such as amorphous carbon or graphite. Occasionally, brown or green spots along surface of a diamond are observed. This is a result of α-irradiation, most likely due to the occurrence of diamond next to a radioactive mineral (e.g. uranium or thorium) present in the mantle or kimberlite magma (Harris, 1987). Coloured diamonds, undergoing artificial treatment such as annealing, can have their colour changed or even removed (Fritsch et al, 1998). In brown diamonds, the colour can be removed by breaking up vacancy clusters into monovacancies by annealing (Fisher, 2009; Smith et al, 2010), while red diamonds under high pressure high temperature annealing and radiation can develop a purple hue (Wang et al, 2005). Aquamarine colour can be induced by electron bombardment (β-irradiation) of a diamond, while yellow, orange, and pink colours are induced by heating diamonds after irradiation (Fritsch et al, 1998). 3.1.3 Diamond resorption Most diamonds undergo dissolution after growth resulting in rounding of the crystal edges (Orlov, 1977; Sunagawa, 1984b; Gurney, 2004). Dissolution, or resorption, is caused by chemical reactions between the diamond surface and volatile fluids within its transporting magma (Arima and Kozai, 2008; Fedortchouk et al, 2010) and can lead to complete dissolution of a crystal. Many crystals exhibit up to 45% loss of original mass (Robinson, 1979); oxidizing agents and temperature are the contributing factors in diamond resorption (Robinson, 1978; Gurney et al, 1993; Arima and Kozai, 2008). These 75  studies provide information about the host magma as the diamond is making its way to the surface, but as indicated by Fedortchouk et al (2007 and references therein), resorption features are only indicative of the last oxidizing event of the diamond and cannot be used to infer anything about the magma before this. The theory that rounding of diamond crystals is not a primary growth form was proven by Seal (1965) in a study where polished cross-sections of diamonds showed rounding that truncated the octahedral growth faces indicating a decrease in size of the original shape. In addition, samples of partially embedded diamond in mantle xenoliths displayed resorption on its exposed surfaces, but none on its embedded surface (Gurney, 1989) indicating the rounding was a post growth process altering original diamond morphology. Resorption affects the edges of octahedra and cuboids creating a rounded (110) surface (Sunagawa, 1984b). The degree to which diamonds are resorbed varies between locality, between diamond crystals within the same suite, and sometimes within the same crystal (Sunagawa, 1984b). As reported by Sunagawa (1984b), pointed faces and edges are the first to be resorbed and as resorption continues, octahedral crystals gradually become rounder. McCallum et al (1994) divided resorbed crystals into 6 progressive classes (Figure 3-3). Class 6 encompasses crystals displaying no resorption. Each subsequent class represents a crystal’s transitional form before reaching Class 1, in which all octahedral faces are resorbed out of existence into a dodecahedron. In addition to rounding, surface features that are relevant and observed within this study are described in detail, while other types are presented in Table 3-2. A common surface feature associated with dissolution is the presence of trigons. Trigons are triangular depressions on the {111} faces of an octahedral crystal while tetragons (the cuboid equivalent) appear on the {100} cuboid faces. The trigons or tetragons have a positive or negative orientation, depending if their outlines are parallel or inverted compared to their host crystal face (Figure 3-4; Robinson, 1978; Field, 1992). The orientation of trigons is dependent on the type of volatiles present within the magma; H2O-induced etching produces negatively oriented trigons and fewer are present on the {111} face, while CO2 –induced etching produces mostly negatively oriented trigons and  76  6  95-99%  Class 1  1-55% preserved  5  4  85-95%  75-85%  2  55-62%  3  62-75%  Figure 3-3 Resorption classification scheme modified from McCallum et al (1994). Percentages are of amount of crystal preservation as the diamond transforms from a complete octahedron (Class 6) into transitions forms (Class 5-2) into a rounded dodecahedron (Class 1).  77  Table 3-2: Chart of surface features seen on diamonds, descriptions, and their respective causes. Using data from Pandeya and Tolansky, 1961; Orlov, 1977; Evans, 1976; Sunagawa, 1984b; Fedortchouk et al, 2007. Please reference Figure 3.1-4 for visual aide. Surface feature Description Reason for appearance Dissolution features -positive (aligned with edges of {111}): dissolution by CO2  trigons  -triangular pits along {111} plane of octahedon; three enclosed sides with either a flat (F type) or point (P type) bottom; cuboid equivalent = tetragons -(hexagonal depressions are seen as well, due to truncation of corners of trigons resulting in hexagonal shapes)  frosting  “cloudy” or roughened look to the diamond  manifests as a series of etch pits due to oxidizing agents due to plastic deformation  deformation lines parallel sets of raised lines along resorbed surfaces 2-D circular elevated shapes on resorbed microdisk patterns diamond surfaces; can be in singles or overlapping groups thin raised lines along planes of diamond laminations  -negative (inverted in relation to {111}): dissolution by H2O, CO2  due to gas bubbles adhering to surface and protecting a small round area from dissolution results from dissolution of {111} face along layers of diamond growth, thus appears to “outline” shape of diamond hillocks elongated raised shapes along surface; found due to preferential dissolution on both resorbed octahedral and cuboid diamonds corrosion sculptures irregularly shaped depressions on a surface due to oxidizing agents attacking surface rapidly; possibly post emplacement of diamonds  Transportation features abrasions  worn down sharp corners or “scrapes” along both features occur post-emplacement of surfaces diamonds and are caused by physical force of transportation from primary to secondary source  percussion marks dents along surfaces or edges  mechanical transport of crystal  78  some positively oriented trigons (Fedortchouk et al, 2007 and references therein). Carbon dioxide induced etching usually results in a larger number of trigons present on the {111} faces (Fedortchouk et al, 2007). Trigons can be further subdivided into P type (point bottomed) and F type (flat bottomed), depending on the morphology of the interior. P type trigons (associated with CO2 –induced etching) are formed at dislocation outcrops, while F types (associated with H2O –induced etching) are formed at point defects (Sunagawa, 1984b; Fedortchouk et al, 2007). Hexagonal depressions are also observed on diamond surfaces, a result from truncation of the points of the triangle in a trigon. An octahedral face can contain none, a few, or many trigons and their appearance is usually not uniform on a single diamond (Orlov, 1977). Frosting is a common surface feature usually occurring on resorbed diamonds (Robinson, 1979), exhibited by a “brushed” texture on the surface (Figure 3-4). Experimental data reported by Robinson (1979) indicate this roughening of the diamond’s surface can result in either coarse frosting or fine frosting. Temperature and oxidizing agents define the difference between the two: coarse frosting occurs between 950 and 1000˚C, with wet carbon dioxide etching the surface, while fine frosting occurs ≤ 950˚C where oxygen gas is the cause. Upon magnification, frosting is manifested as a concentration of pits along the diamond surface. These pits can be prismatic, negatively oriented trigons (with flat bottoms), or hexagonal depressions (Robinson, 1979).  3.2 Physical characteristics of meta-Conglomerate hosted diamonds The diamonds in this study are classified using a combination of Orlov (1977) and Sunagawa (1984b) classification schemes. They are divided into four classes: octahedra (and macles), cuboids, cubo-octahedra, and polycrystalline. Resorption classes are modeled after McCallum et al (1994) and surface features such as etching are described using the scheme of Robinson (1978). Because of the paucity of polycrystalline diamond found within the population of meta-conglomerate hosted diamonds, unless otherwise stated, descriptions are of single diamond crystals only. See  79  positive trigons  hexagons  negative trigons  steps  microdisk patterns abraded edge  hillocks  corrosion sculptures  frosting percussion marks  abraded surface  Figure 3-4 Schematic drawings of different types of surface features found on diamond. Top most figure displays dissolution related features on octahedral crystals. Middle figure displays dissolution related features seen on resorbed diamond surfaces. Bottom most figure displays non-dissolution mechanical related features observed on diamonds. Modified after Stachel, 2007.  80  Figure 3-5, 3-7 to 3-8, and 3-10 for photographs of Wawa meta-conglomerate hosted diamonds. A detailed chart of each diamond’s characteristics is presented in Appendix C. 3.2.1 Size The meta-conglomerate hosted diamonds (383 crystals) range from 0.1-2.0 mm in size, with an average size of 1x1-1x1.5 mm (at the longest and widest dimensions). The largest crystal measures 3.25x1 mm. Macrodiamonds (>0.5 mm in one dimension) and microdiamonds (<0.5 mm in one direction) were taken for morphology studies (Figure 35). Macrodiamonds consist of 352 diamonds ranging in sizes on average from 1-2 mm and microdiamonds are comprised of 31 crystals, on average 0.3-0.5 mm. Of the 383 diamonds studied, most (55%) are fragments while the rest (39%) are whole crystals. Fragments are, defined by this author, those missing more than 1/3 of their crystal. Whole crystals include those that are chipped or fractured slightly but display at least 2/3 of their original crystal form. The general shape of each crystal at the time of observation is described as ‘morphology’, while primary growth form is described as ‘growth habit’. Unless otherwise stated, all characteristics described below are of both macro- and microdiamonds. 3.2.2 Crystal morphology and growth habits In macrodiamonds, the most common crystal morphologies are octahedra and its various forms including octahedra with flat faces, octahedra with polycentric growth (i.e. stepped faces), and distorted octahedra that are elongated or flattened (Figure 3-5b-d; Figure 3-6). Cuboids and various forms only represent 12% of the total macrodiamonds. Various forms of the cuboids include cuboids with polycentric growth, re-entrant angledgrowth cuboids, and crystals that are distorted (Figure 3-5e). Of the entire population, only 11 polycrystalline crystals are present. Severe resorption of a diamond displays shapes described as dodecahedra. Dodecahedra are 12-face resorbed diamond crystals, displaying a rounded or flattened lemon shape (Figure 3-7a, b). Within the Wawa meta-conglomerate hosted population, dodecahedra shapes make up 15%. Crystals with a combined morphology of cuboid and 81  a  b  c  d  e  Figure 3-5 Photographs of Wawa meta-conglomerate hosted diamonds. a) Overall morphology of diamonds (scale is 3 cm); b) octahedral shapes; c) octahedral shapes with polycentric and stepped growth; d) distorted and stepped octahedra; e) various cuboid shapes. Note interpenetrating twinned cuboid in second row. Millimeter scale for b-e.  82  a  macrodiamond (>0.5 mm in one dimension) 3%  7%  40%  octahedra and related forms unknown  15%  cuboids and related forms dodecahedra  12%  cubo-octahedral forms macles 22%  b  n=352  microdiamond (<0.5 mm in one dimension) 23%  40%  octahedra and related forms cuboids and related forms dodecahedra cubo-octahedral forms  10%  unknown 18%  8%  n=31  Figure 3-6 Distribution of morphology within the meta-conglomerate hosted diamond suite for a) macrodiamonds and a) microdiamonds. Microdiamonds do not display macle forms. These distributions are for single crystal diamonds only and does not account for polycrystalline crystals or fragments.  83  a  b  c  d  e  f  Figure 3-7 Photographs of Wawa meta-conglomerate hosted diamonds (with millimeter scale). a) Dodecahedral shapes, a flattened dodecahedral shape is seen at left; b) dodecahedrals with distorted shapes; c) macle; d) macle displaying resorption; e) microdiamond octahedra with normal and polycentric morphologies; f) examples of diamond aggregates.  84  octahedral (such as a cuboid with octahedral growth at its apexes) make up 7%, while twinned crystals (macles; Figure 3-7c, d) constitute only 3% of the population. The remaining diamonds (22%) were classified as unknown, due to severe fragmentation or the occurrence of bizarre shapes. Like the macrodiamonds, microdiamonds (<0.5 mm in one direction) contain mostly octahedra and its various forms (Figure 3-7e), followed by dodecahedra, cubo-octahedral crystals, and cuboids. Unknown morphologies make up 23%. Seventy-six percent of diamonds originally possessed a primary octahedral growth habit and 13% experienced cuboid growth. Coated diamonds are observed within this population (6%). All of these diamonds displayed a small octahedral crystal surrounded by a fibrous cubic coat. None of the reverse was seen. Five percent of diamonds observed had undetermined primary growth habit. A few diamond crystals display interesting traits. One cuboid diamond contains an inverted cuboid void the center of one face, indicating a cuboid mineral or possibly another diamond had grown simultaneously with it. A most interesting case of twinning is observed, where a diamond was made up of three interpenetrating cuboid shapes. One polycentric octahedrally grown diamond had a smaller secondary diamond growth on one of its sides and only the smaller diamond contained inclusions. Such a small amount of polycrystalline diamonds within this population is attributed to the fact they are not as resilient as whole crystals, resulting in a biased plot. Single crystals are much more likely to survive emplacement, erosion into a secondary deposit, as well as the mining extraction process as compared to polycrystalline diamonds. Single crystals dominate, constituting 93% of meta-conglomerate diamonds and only 1% was recognized as displaying polycrystallinity and classified as bort (granular aggregates; Figure 3-7f). Six percent were of undetermined polycrystallinity (due to severe fragmentation). 3.2.3 Surface features No mechanical abrasion features are observed on any diamonds. Resorbed diamonds do not display many features other than frosting, since any original surface 85  features have since been oxidized away. Negative trigons are observed on almost all octahedra. Many microdiamonds were contaminated with an unknown dark brown/black adhesive substance, attributed to be part of the extraction process. This adhesive was very difficult to remove and thus obscured most surface features. Several diamonds had pits present on the surface, but none contained deformation lines. 3.2.4 Body colour Macrodiamonds display a wide variety of colours (Figure 3-8a, b) and are broken down into the following categories: colourless or opaque white (64%), yellow (24%), green (4%), grey (4%), brown (2%), pink (1%), and black (1%). Only cuboid forms are grey, green, brown, or black. Octahedra and their various forms are mostly colourless or opaque, but are never black. 3.2.5 Degree of resorption There was almost an even split between diamonds displaying resorption (51%) and those displaying none (43%) (Figure 3-8c-f). A minority of diamonds (6%) had undetermined resorption. A further and more specific breakdown of the resorption category reveals the diamonds fall into each category of a slightly modified classification scheme of McCallum et al (1994); most diamonds displayed mostly no resorption, followed by slight resorption, moderate resorption, and high resorption (Figure 3-9). Resorption statistics are for both macro- and microdiamonds. 3.2.6 Inclusions Fifty-three percent of diamonds contained visible inclusions while 45% did not. Inclusion-containing diamonds were divided into the following subcategories: containing black and flat inclusions assumed to be graphite (17%), containing nongraphite inclusions (17%), and containing a combination of both types of inclusions (6%). Non-graphite inclusions (Figure 3-10a, b) are observed to be dark or clear inclusions with observable volume (i.e. non-planar), as opposed to graphite that usually occurs as flat two-dimensional impurities. Fifteen percent of crystals had undetermined amounts of inclusions. These observations are biased against crystals that are too opaque 86  a  b  c  d  e  f  Figure 3-8 Photographs of Wawa meta-conglomerate hosted diamonds (with millimeter scale). a-b) The variety of colours and shapes observed in this population.; c) magnified photograph of resorbed steps on an octahedral surface; d) resorbed cuboid diamonds; e) various stages of resorption as seen on octahedrally grown diamonds; f) comparison between an unresorbed octahedron and a frosted dodecahedron  87  Degree of Resorption  Class 1 (high)  9% 15%  Class 2-3 (medium)  28%  Class 4-5 (slight)  Class 6  42%  (none)  Undetermined  7% 20  40  Frequency (%)  n=383  Figure 3-9 Distribution of meta-conglomerate hosted diamonds within resorption classes. This encompasses both macro- and microdiamonds. Classification based on modifed scheme of McCallum et al (1994).  88  a  b  Figure 3-10 Photographs of Wawa meta-conglomerate hosted diamonds. a-b) octahedra with visible mineral inclusions. Due to the purple colour, it is inferred these inclusions consist of garnet. Scale for (a) is 0.5 mm, (b) is 1 mm.  89  for visibility or very small crystals. More detailed studies on the meta-conglomerate hosted diamonds reveal these mineral inclusions are Cr-rich garnet, chromite, Mg-rich olivine, orthopyroxene, sulfide, and one occurrence of secondary carbonate, indicating a peridotitic paragenesis (C. Miller, pers. comm.).  3.3 Physical characteristics of meta-breccia hosted diamonds The meta-breccia hosted diamonds were characterized by Lefebvre (2004), unless otherwise noted. All 80 diamonds analyzed were ~0.5-1.4 mm in at least two dimensions, of mainly octahedral forms and their associated aggregates (69%), cubic forms and associated aggregates (23%), cubo-octahedral forms and associated aggregates (7%), macles (9%), and those of unknown morphologies (4%). Forty-two percent of diamonds are whole crystals and 58% are broken. These diamonds display the following colours: colourless (49%), heterogeneous (24%), yellow (11%), brown (10%), black (3%), and grey (3%) (De Stefano et al, 2006). The 80 meta-breccia hosted diamonds (both aggregates and single crystals) are separated into the 6 different resorption classes (of McCallum et al, 1994): None (class 6): 70%, slight resorption (class 4-5): 66%, medium resorption (class 2-3): 9%, high resorption (class 1): 7.5%, undetermined: 6%. Resorption specific surface features such as trigonal and/or hexagonal pits are found on 57% of the diamonds, but high resorption features such as terraces and elongate hillocks are seen on only 4% and 1% of the Wawa diamonds respectively (Lefebvre, 2004). A preliminary inclusion analysis by Lefebvre (2004) reports 58% of meta-breccia hosted diamonds contained either colourless or graphite inclusions. According to further mineral inclusion studies by De Stefano et al (2006), diamonds of peridotitic, eclogitic and unknown parageneses were found. Four diamonds contained both eclogitic and peridotitic paragenesis inclusions. De Stefano et al (2006) also found plagioclase present as inclusions as well. 90  Chapter 4: Infrared absorption properties of diamonds 4.1 Nitrogen systematics Nitrogen (N) is the most common diamond impurity (Kaiser and Bond, 1959), being present in ~98% of natural occurring diamonds worldwide (Evans, 1992). Nitrogen infiltrates the diamond’s lattice during growth as single substitutional atoms (C-centers). At mantle temperatures, nitrogen atoms present in the lattice migrate together to form pairs of nitrogen atoms (A-centers). As time increases, the pairs migrate into four nitrogen atoms arranged in a tetrahedron surrounding a vacancy (B-centers) (Woods, 1986). Byproducts of nitrogen aggregation are platelets, which are planar defects within the crystal, termed B’ defects (Woods, 1986; Clark et al, 1992). Their exact nature is still under investigation, but it is known they do not consist solely of N (Fallon et al, 1995) and perhaps are caused by carbon-carbon bonds stretching (Clark et al, 1992). The relationship between B’ defects and B-centers is proportional in ‘regular’ type diamonds, which indicate a continual aggregation of A-centers into B-centers while ‘irregular’ type diamonds contain little to no correlating B’ defects due to degradation of the planar defects (Woods, 1986). Speculations have been made for the cause of platelet degradation including catastrophic thermal events (i.e. extreme temperatures), or shear stress of the diamond lattice (Woods, 1986). Diamonds with detectable N (>10 ppm) are classified as Type I and those with N concentration below the minimum detection limit of infrared spectroscopy (< 10 ppm N) are classified as Type II (e.g. Evans, 1992; Zaitsev, 2001). Type I diamonds can be subdivided into Type Ia and Ib, depending on the aggregation state of N. Rare Type Ib diamonds contain single N atoms (C-centers), while Type Ia diamonds contain aggregated N atoms that are present as A-centers (Type IaA) or B-centers (Type IaB). Diamonds with both A and B centers present are classified as Type IaAB and are the most common aggregation type (Woods, 1986). Type II diamonds can also be further subdivided into a, b, or c depending on the type of other impurities present such as hydrogen or boron (e.g. Fritsch, 1998), but these types are not emphasized in this study. See Figure 4-1 for a simplified diamond classification scheme. 91  Diamond Type I  Type II  >10 ppm  Type Ia nitrogen in pairs  nitrogen in fours  Type IaA  Type IaB  <10 ppm  Type Ib  Type IIa  Type IIb  Type IIc  single nitrogen atoms  boron and hydrogen impurities  boron impurities  hydrogen impurities  disproportional proportional platelet quantity platelet quantity Type IaB' regular  Type IaB' irregular  Figure 4-1 Classification of diamond pertaining to nitrogen content and aggregation, modified after Evans, 1992.  92  Fourier Transform Infrared (FTIR) spectroscopy is a non-destructive technique by which infrared radiation is passed through a sample and the frequencies of molecular vibrations are recorded in an absorption spectrum. Peaks reflecting nitrogen defects within the diamond lattice are represented in the one-phonon region, <1333 cm-1 (Figure 4-2a; Titus et al, 2006). The absorption of the diamond itself is observed within the twophonon region, 1333-2666 cm-1 (Figure 4-2a; Titus et al, 2006). The three-phonon region (2667-3100 cm-1) displays hydrogen defects present within the diamond, but these defects are not addressed here (Figure 4-2a). Least square techniques was applied for quantitative analyses. Single N substitution results in a peak at 1130 cm-1 and smaller auxiliary peak at 1344 cm-1 (Figure 4-2b; Clark et al, 1992; Evans, 1992). A-centers (N pairs) display a prominent peak at 1282 cm-1, followed by a slight drop at 1242cm-1, with a secondary broad band at ~1150-1215 cm-1 (Mendelssohn and Milledge, 1992; Taylor et al, 1990). Bcenters (a tetrahedron of N) have a main peak at 1175 cm-1 with a subsequent dip, followed by a smaller peak at 1100 cm-1. A steeper dip and a low intensity peak at 1010 cm-1 follows this smaller peak (Taylor et al, 1990). The B’ defect (platelets) is displayed as a peak at 1372 cm-1 (Woods, 1986; Titus, 2006). As mentioned above, the B’ peak is proportional with B-center aggregation until its degradation occurs (Figure 4-3). Factors responsible for nitrogen aggregation are mantle residence time, mantle residence temperature, and initial N content within the diamond (Evans, 1976; Woods, 1986;). Nitrogen present as C-centers are rather transitory and begin to aggregate quickly, thus N content regarding C-centers is not taken into account for residence analyses (Taylor et al, 1990). Experimental and theoretical results show the extent of aggregation from A-centers to B-centers increases for longer mantle residence times or higher mantle storage temperatures (Taylor et al, 1990). This theory is supported by data presented in Evans (1992 and references therein), where experimentally annealed diamonds resulted in a decrease of concentration of single substitutions of nitrogen, into more multipart N aggregated states. The equations presented in Taylor et al (1990) determine the relationship between N aggregation, expressed as %B, and total N present, for different temperatures at a given time. This progression of aggregation ceases to 93  a  three phonon  Absorbance  H region  3000  3500  two phonon  one phonon  diamond region  impurity region  2000 2500 Wavenumbers/cm -1  1000  1500  b A-centers  B-centers with B’ peak  -1  Absorbance  1150-1215 cm  B’ peak -1 1372 cm  -1  1100 cm  1300  -1 -1  drop  1500  -1  1175 cm  1282 cm  drop  1100  900 1500  Wavenumbers/cm-1  1300  1100  1010 cm  900  Figure 4-2 a) Infrared spectrum of a theoretical diamond displaying the various peaks associated with the one, two, and three phonon ranges of wavelengths. Diamond only displays peaks within the two phonon range, nitrogen is visible within the one phonon range, and hydrogen impurities are seen within the three phonon range. Modified after McNamara et al, 1994. b) The impurity region (one phonon range) on infrared spectra of theoretical diamonds containing different types of N aggregation. Note the location of peaks in regards to A-centers and B-centers. In accordance with Woods (1986), B’ peaks are only seen associated with B-centers 94  a  d  b  f  absorption  B’ peak  c  g B’ peak no longer proprortional  d  1650  h  900 1650  wavenumber/cm -1  900  Figure 4-3 Infrared absorption spectra of a) regular Type IaA diamond and the change in shape of spectra (b-d) as pairs of N aggregates into the more complex aggregation. The platelet concentration increases as A-centers aggregate into B-centers, resulting in a Type IaB diamond with corresponding platelet concentration (e). Irregular diamonds display platelet degradation (f-h) as the N aggregation moves into a pure Type IaB without platelets present (h). Modified after Woods, 1986.  95  continue once the diamonds are entrained and brought up to the surface in host magmas (Evans et al, 1981).  4.2 Analytical methods Twenty-four diamonds were analyzed for nitrogen content and aggregation state studies using a Nicolet 710 Fourier transform infrared (FTIR) spectrometer with a nicPlan IR microscope attachment and a liquid nitrogen reservoir, at the Department of EOS (UBC). 256 scans. Forty-eight diamonds were subsequently analyzed on a Fourier transform infrared (FTIR) microscope fitted with a Thermo Nicolet Nexus 470 FTIR spectrometer and a liquid nitrogen reservoir at the (Department of Earth and Atmospheric Sciences, the University of Alberta). Duplicate samples were used to ensure compatibility of analyses from both labs. Absorption spectra were measured in the range of 4000–650 cm–1 at a resolution of 8 cm-1 with a signal of 200 scans. Diamonds were mounted on the edge of a glass slide and spectra were recorded at the point of maximum light transmission through the sample. A Type II diamond of known thickness was used as a reference to correct for varying diamond sample thicknesses in the mounted samples. Baseline spectra corrections were performed using Omnic version 6.0a software and deconvoluted using least square techniques into spectra of C, A, and B-centre components single N, paired N, tetrahedral N, and platelets as described in De Stefano et al (2006). Thermometry of diamonds is calculated using equations presented in Taylor et al (1990), using a mantle residence time of 300 Ma.  4.3 Infrared spectroscopy of meta-conglomerate hosted diamonds Out of 72 meta-conglomerate hosted diamonds, 34 diamonds are Type IaA, four diamonds are Type IaB, eight diamonds are Type II, and the remaining 26 diamonds are Type IaAB with 5-85% of totally aggregated N (Table 4-1; Figure 4-4a). There are no Type Ib diamonds (i.e. all N is aggregated and significant concentrations of singlesubstitution N are not present). Specific breakdowns of N ppm in the diamonds are presented in Figure 4-4. There are no consistent differences with respect to the N systematics between macro- (>0.5 mm in one dimension) and microdiamonds (<0.5 96  Table 4-1 Nitrogen related characteristics of 72 meta-conglomerate diamonds. Three meta-breccia hosted diamond fragments were analyzed for comparison purposes. Sample # Size (mm Wawa meta-conglomerate 16388B 0.6x0.5 16406 0.7x0.5 16407 0.5x0.8 16417 0.5x0.5x0.5 16418 0.5x0.8 16421 0.5x0.5 16429B 0.5x0.5 16431B 0.5x0.5 16431E 0.1x0.1 16442 0.5x0.2 16448 1x0.75 16449B 0.6x0.6x0.5 16459 0.8x0.8 101AF1-1 1x1 101AL-1, 1-9 1.25x0.75 101AL-1, 2-1 1x0.5 101AL-1, 2-10 2x1.25 101AL-1, 3-4 1.75x1 101AL-1, 3-6 1x1 101AL-1, 3-10 1.5x1 101AL-2, 1-5 1.25x0.5 101BF-1, 1-7 1x1x1 101BF2-1 1x1 101BL-1, 1-3 2.25x0.5 101BL-1, 1-6 1.25x1 101BL-1, 1-10 1.5x1.75 101BL-1, 2-2 1x0.75 101BL-1, 2-8 1.5x1 101BL1-2 101BL-2, 1-10 1x1x1 101BL-2, 2-1 2x0.5 101BL-2, 2-2 1x1 136AL-1, 1-10 1x1x1 136AL-1, 2-6 1.5x1x1 136AL-1, 3-2 1.5x1 136AL-2, 1-2 1x1 136AL2-1 1x1x0.5 136BL-2, 1-1 1x1 136BL-2, 1-3 2x1 136BL-2, 1-6 1x1 184AF1 1x1 184BL 1x2 "401AL-1, 1-3" 1x1 401AL-1, 3-3 1x0.5 401AL-1, 3-6 1.5x1.75 401AL-1, 3-7 1.25x1 401AL-2, 1-7 1.25x0.75 401AL2-1 0.5x1 401BF1-1 1x1 401BL 1x1x1 401BL-1, 1-4 1.25x1.25  A-centers (ppm) 518 268 667 689 113 819 99 518 102 19 192 81 255 232 42 139 128 41 532 75 453 103 118 40 253 244 <MDL 22 100 239 71 17 352 281 20 231 205 188 45 174 <MDL <MDL 206 39 309 238 60 19 35 318 52  N systematics B-centers N Aggregation (ppm) % B-centers Total N (ppm) 246 <MDL 66 30 77 <MDL 16 <MDL 88 <MDL 21 35 <MDL <MDL <MDL <MDL <MDL <MDL <MDL 110 <MDL <MDL <MDL <MDL <MDL <MDL 232 174 <MDL 35 28 80 331 <MDL 14 108 48 <MDL 15 148 <MDL <MDL 69 106 281 <MDL 89 34 <MDL 19 11  32 0 9 4 40 0 14 0 47 0 10 30 0 0 0 0 0 5 0 59 0 0 0 0 0 0 99 89 0 13 28 82 49 0 40 32 23 0 25 46 0 0 25 73 48 0 60 64 0 6 17  764 268 733 719 189 819 115 518 190 19 214 115 255 232 42 139 128 43 532 185 453 103 118 40 253 244 234 196 100 274 98 97 683 281 34 339 252 188 61 322 <MDL <MDL 276 145 590 238 149 53 35 337 63  97  A-centers (ppm) 152 596 56 34 <MDL 203 30 238 63 <MDL <MDL 150 196 33 150 <MDL 32 137 15 <MDL <MDL  N systematics B-centers N Aggregation (ppm) % B-centers Total N (ppm) <MDL 0 152 <MDL 0 596 26 32 82 <MDL 34 0 <MDL <MDL 0 <MDL 203 0 <MDL 30 0 <MDL 237 0 <MDL 67 <MDL <MDL <MDL 0 <MDL <MDL 0 <MDL 150 0 65 261 25 <MDL 33 0 <MDL 150 0 <MDL <MDL 0 <MDL 32 0 <MDL 137 0 83 98 85 <MDL <MDL 0 <MDL <MDL 0  Sample # Size (mm 401BL-1, 1-10 1x1 401BL-1, 2-1 1.5x1 401BL-2, 1-4 1x1 401BL1-1 1x1x1 2101AF1 1.5x0.5 2101AL1 1x1.5 2101AL3 2x0.5 2101BF1 1x1 2101BL1 1x1 2101BL2 2x0.5 2101BL3 1x1 2136AF1 1x0.5 2136AF2 1x1 2136AF3 1.25x1 2136AL1 1x1 2136AL2 1x0.75 2136AL3 1.5x1 2136BL1 0.75x1 2136BL2 2x0.5 3184BL1 1x1 3184BL2 1.5x1 Wawa meta-breccia 39c fragment* 103 107 51 210 40c fragment* 166 <MDL 0 166 58b fragment* 131 <MDL 0 131 <MDL - below minimum detection limit; Cuboid diamonds are in bold Microdiamonds are in italic Measurements are of widest and narrowest part of octahedra/dodecahedroids/macles; cuboids are measured in 3 dimensions. * macrodiamond below <2 mm in all dimensions; exact original size unknown  98  50  n=72  40 30 20 10 20  30  40 50 60 %B, N aggregation  70  80  90  100  1000  0  20  40  %B  50 12  12  60  80  C 1300˚  ˚C  ˚C  00  11 5  10  C  100  1100˚C  N content (ppm)  b  10  0˚  0  1050˚C  Number of samples  a  100  Figure 4-4 a) Histogram displaying %B N aggregation. b) Plot of total nitrogen content vs. %B in meta-conglomerate hosted diamonds. Calculated isotherms are from Taylor et al (1990), using a 300 Ma mantle residence time. Detection limits and error bars (20%) from deconvolution methods are based on De Stefano et al (2006 and references therein).  99  mm). A 300 Ma residence time was used to calculate mantle residence temperatures (Figure 4-4b). The N characteristics can be explained by residence at 1000-1200˚C, which broadly corresponds to temperatures in the diamond stability field in a cratonic root stabilized at ~ 300 Ma, the average age of the northern Superior craton on which the diamond host rocks are emplaced (Percival et al, 2006). 4.4 Infrared spectroscopy of meta-breccia hosted diamonds Nitrogen analyses performed by De Stefano et al (2006) describe forty-one diamonds from the meta-breccia host rocks were divided between Type IaAB (20 diamonds), Type IIa (14 diamonds) and Type IaA (7 diamonds) with nitrogen contents ranging from 0-740 ppm, although the majority of diamonds have about 300 ppm. None of the meta-breccia hosted diamonds have C-centers that display absorption peaks that indicate single substitutional nitrogen atoms to be present (De Stefano et al, 2006). The N aggregation states have a bimodal distribution and clustering of the stones into nonaggregated (<30 %B of fully aggregated N, including Type II) or highly aggregated (>60%B of fully aggregated N).  100  Chapter 5: Luminescence of diamonds 5.1 Introduction Luminescence is a phenomenon by which electrons in luminescent centers present within a crystal lattice undergo excitation, resulting in various processes due to electrons returning from excited states (e.g. Marfunin, 1979; Walker, 1985). These luminescent centers are typically impurities, defects, and vacancies present within the crystal (Zaitsev, 2001; Gaft et al, 2005). The excitation (via ultraviolet radiation, X-rays, etc.) is enough that the valence electrons of the centers are able to jump the band gap into the conduction band, a higher energy state. The band gap structure varies between minerals and since this structure determines the number and wavelength of resulting luminescence peaks, diagnostic spectra are produced for various minerals and their defects (Henderson and Imbusch, 1989). Excited electrons can return to their ground state radiatively by emitting a photon of light. The energy of the photon corresponds to the energy difference between the conduction and valence bands (Figure 5-1). This photon also corresponds to a wavelength on the visible colour spectrum resulting in a coloured “glow” observable with the eye or as peaks on a spectrum with its position consistent with the appropriate wavelength number (e.g. Pagel et al, 2000). Non-radiative return can occur if the transition of the electron results in an increase of vibrational energy of the electron in comparison to its unexcited state, creating a lateral displacement by way of phonons (Walker, 1985; Gaft et al, 2005) (Figure 5-1), also manifested as peaks on a spectrum. It is possible that no phonons are created during the electron transition from excited to unexcited state, resulting in a narrow and sharp peak, called the zero-phonon line (ZPL) (Walker, 1985; Marfunin, 1989). Zero-phonon lines (ZPL) are usually accompanied with a broader peak appearing at higher wavelengths; these sidebands are results of phonon resonance from within the crystal’s lattice (Remond et al, 2000). Electron returns producing no phonons and electron returns accompanied by phonons occur at the same time, but the phonon-producing peaks cover up the zero-phonon lines at higher temperatures (Walker, 1985). Therefore, lower temperature luminescence spectroscopy results in a better resolution spectrum of the same mineral as the vibrational resonance  101  typically accompanying electron transition is eliminated (Marfunin, 1988; Gaft et al, 2005). Luminescent spectroscopy is recorded as frequencies of emittance peaks onto a spectrum. The axes are typically labeled as wavelength in nanometers (nm) against arbitrary intensity in counts per second (cps). The wavelengths correspond to a colour range within the visible spectrum. Luminescent spectra measure the luminescent intensity over a range of wavelengths and the intensity is dependent on the orientation of the luminescent centers in relation to the mineral’s own crystallographic lattice orientation (Gaft et al, 2005). As Walker (2000) reports, the position of peaks not only indicates the separation of the emitting state and ground state of electrons within the sample, but the origin of the emittance (i.e. which luminescent centers are responsible for emission). Within this study, two types of luminescence techniques are used: cathodoluminescence (CL) and photoluminescence (PL). The emittance of CL is produced when a sample is bombarded with electrons from a cathode. This process only excites the surface, up to ~5 µm (Clark et al, 1992; Hanley et al, 1997; Zaitsev, 2001) as opposed to penetrating the entire volume of the sample (as with PL). The emitted colour is analyzed by visual observation through an optical CL microscope and is thus arbitrary since it can vary depending on individual scientists, but quantifiable CL results are measured by spectral analysis of peaks. Distribution of the emitted light over wavenumbers and relative intensities of the CL peaks in a spectrum depend on the excitation power of the electron beam and on the temperature (Marfunin, 1989; Clark et al. 1992). Photoluminescence (PL) is activated in a material usually via ultraviolet radiation and in contrast to CL, it is more representative of the entire volume of a sample as it collects bulk rather than surface information (Clark et al, 1992; Hanley et al, 1997). Optical PL is possible, but is not addressed in this study. Spectral PL results are recorded similarly to CL results (on a spectrum with wavelength vs. intensity), but the wavelength range of luminescence is restricted depending on the wavelength of the excitation beam. As the laser beam enters the sample, only luminescent features of equal or lower energy  102  can be produced as a result (i.e. a 488 nm laser will not display spectral peaks higher the beam’s excitation energy). In order to see spectral peaks at shorter wavelengths, more energy is needed to activate them. The main difference between these two methods of excitation is their activating energies. Cathodoluminescence (CL) typically is activated in the range of 0-50,000 eV, while PL is activated within the range of 1.8-4.9 eV (Marshall, 1988). Photoluminescence (PL) at lower temperatures always produces narrower peaks than wide CL peaks (Magee and Taylor, 1998) (which result from “overexcited” electrons that travel in the conduction band), thus pinpointing positions of optical centers in diamonds responsible for emittance. Cathodoluminescence (CL) has a variety of application when it comes to diamond samples. It has been used to map out internal growth structure (Bulanova, 1995), zoning (Lang et al, 1992), surface textures (Ponahlo, 2000) and distribution of impurities within the diamond (Barjon et al, 2007). Optical CL and CL spectroscopy, enables a characterization of a set of diamonds based on specific traits allowing comparison of diamond CL spectra between diamonds in question and diamonds with known characteristics (e.g. Lindblom, 2003). This application is not restricted to diamond; CL spectroscopy can help identify source locations or synthetic vs. genuine mineralogy in emeralds, alexandrite, sapphire, and jadeite (Ponahlo, 2000). Photoluminescence (PL) has been used in studies regarding synthetic diamonds (Yelisseyev et al, 2003), natural vs. synthetic diamond characterization (Lipatov et al, 2010), and growth habit of natural diamonds (Lang et al, 2007). As discussed in a previous section, nitrogen is the most common type of substitutional impurity in diamond (e.g. Stachel, 2007) and is the source of the most common luminescent center (Marfunin, 1979; Walker, 1985; Gaft et al, 2005). Various nitrogen impurity complexes display various diagnostic peaks in the spectrum because the peaks reflect their arrangements of substitutional ions and positions within the “host” lattice (Gaft et al, 2005). Common luminescent centers in diamonds are the N3 and H3 defects (Marfunin, 1979; Gaft et al, 2005). The N3 is an arrangement of three nitrogen atoms surrounding a common vacancy, presented as a ZPL at ~415 nm. The H3 defect is 103  a pair of nitrogen atoms around a vacancy, displaying a ZPL at ~503.2 nm. Two other nitrogen-related luminescent centers are NVo and NV–, a neutrally and negatively charged N atom and related vacancy, apparent by emission peaks at 575 nm (for NVo) and 637 nm (for NV–) (Zaitsev, 2001). Zaitsev (2001) reports these latter luminescent centers are known to only be PL active and are not exhibited within CL spectrum.  5.2 Analytical methods Optical cathodoluminescence (CL) studies were performed at the Department of Earth and Ocean Sciences (University of British Columbia) on a Cambridge Instruments Cathode Luminescence (CITL 8200 mK4) system with an attached optical microscope (2.5× lens), using an accelerating 7.5 μm beam of 15 kV and electron beam current of 300 μA. The diamonds were placed on glass slides or were mounted into CL inactive putty in a steel recessed tray, which fit into a vacuum chamber maintained with a Varian DS 102 pump. Images were collected using an attached digital Nikon Coolpix 995 camera. Exposure times for photographs varied from 0.1–10 s, depending on the intensity of CL. For CL spectral analysis, diamonds were also analyzed at the Department of Earth and Ocean Sciences (University of British Columbia), using an Electron Optics Service CL spectrometer attached to Philips XL 20 SEM. This spectrometer is a highly sensitive 2048 charge coupled device (CCD) with grating optimized for a 360–1000 nm spectral coverage. All CL spectra were collected under the same analytical conditions. Acceleration voltage was set at 15 kV, with the electron beam current of 100 μA and beam size of 6–7 μm. The spectra were taken at 18 °C with diamonds emitting blue CL colour (peaks at 420 and 490 nm) as an internal standard. Resulting spectra were processed using Ocean Optics Inc. Cathodoluminescence spectra with multiple overlapping peaks were further deconvoluted with Peakfit. Input data were smoothed using Gaussian convolution to remove noise and the data were deconvoluted using a Gaussian algorithm. The standard error in the X position of peaks (0.2–2 nm) was calculated to 95% confidence limits with a least square value of ~0.999 (De Stefano et al. 2006). 104  Photoluminescence (PL) analyses of 12 meta-conglomerate hosted diamonds were completed at the Canadian Gemological Laboratory, New York on a Renishaw In Via System spectrophotometer at liquid N2 temperatures (80 K). One Type IaA (>10 ppm N in A aggregation) and two Type IaAB (>10 ppm N in A and B aggregation) diamonds with 20 and 80% B-aggregation were also recorded at these conditions as references. In addition, three meta-breccia hosted diamonds were analyzed for data comparison against meta-conglomerate hosted diamonds. The photoluminescence spectra were recorded with a resolution of 0.01 nm and grating 1800 l/mm after 10 s exposure time using a 1 μm beam of a 488 nm laser at the liquid nitrogen temperature. Laser intensity was kept at 100 or 10% depending on saturation of the PL signal.  5.3 Luminescence of meta-conglomerate hosted diamonds 5.3.1 Cathodoluminescence of meta-conglomerate hosted diamonds All 69 diamonds on which optical CL analyses were performed display colours of various intensities, with only one crystal exhibiting a typical blue CL colour (Figure 52a). In macrodiamonds (>0.5 mm in one dimension), the most common CL colour observed is green followed by yellow, orange, pink, and red-orange (Figure 5-2b). In contrast, microdiamonds (<0.5 mm in one dimension) tend to be mostly yellow, orange or red, but are rarely green. For spectral CL analysis results, macrodiamonds mostly show a dominant peak at 520 nm, whereas corresponding microdiamonds exhibit two peaks at about 576 and 600 nm (Figure 5-3). Again, none displayed a peak in the 420 nm (blue) region. Rarely, microdiamonds demonstrated patches of multiple CL colours (Figure 5-2a) due to either heterogeneity within the crystal or polycrystalline growth. Cathodoluminescence (CL) spectroscopy (Table 5-1) show that in all macro- and microdiamond (except sample 401 AF) samples, the highest intensity peak is at 520 nm (Figure 5-3). This peak is accompanied by a minor wide peak at 420–440 nm and by peaks at ~575 and 540 nm. 5.3.2 Photoluminescence of meta-conglomerate hosted diamonds Eight studied diamonds display a major vibronic system with the zero-phonon 105  conduction band  different vibrational energy  photon  valence band phonon Figure 5-1 A schematic diagram of the processes occuring during electron transition (i.e. luminescence). Solid lines indicate radiative return of an electron resulting in a photon while dashed lines indicate non-radiative return of electrons resulting in a phonon. Modified after Walker, 1985.  106  a  b  Figure 5-2 Optical cathodoluminescence (CL) photographs of a) meta-conglomerate diamonds. All photographs are of macrodiamonds (>0.5 mm), with the exception of the last row, which are CL photographs of microdiamonds (<0.5 mm). b) Optical CL photographs of meta-breccia diamonds.All scales are 0.5 mm. 107  Table 5-1 Reference table of meta-conglomerate and meta-breccia samples for cathodoluminescence (CL) and photoluminescence (PL). Sample Size (mm) Luminescence Number Optical CL Optical CL CL Emittance PL Emittance colour Intensity lines (nm) lines (nm) Wawa meta-conglomerate 16398A 0.7x0.5x0.5 green + na 611, 543, 503 401AF 1.25x1x1.5 green + 515 637, 503 136AL 1x1x1 yellow ++ 520 637, 503 401BL 1x1x1 green + 513 575, 512, 503 1.5x1x1 16395 green ++ 520, 430 na 1x1x1 101AF1-1 green + na na 1x1x1 101BF2-1 green na na 1x1x1 401BF1-1 green + na na 1x1.5x1 2101AL1 green + na na 1x1x1 2101BL1 green + na na 0.75x1x1 2136BL1 green + na na 1x1x1 184AF1 yellow na na 101BL-2, 1-10 1x1 green + na na 1x2x1 184BL green + na na 16448 1x0.75 x0.75 green ++ 576, 521 na 16396 1.25x1x1 green 580, 520 na 1x1x1 2101BF1 green + na na 16419C 0.5x0.5x0.5 green 502, 439 na 16419B 0.5x0.5 x0.5 yellow ++ 573, 520, 439 na 16429C 0.75x0.5x0.5 green ++ 573, 520, 439 na 1x1x0.5 136AL2-1 green + na na 0.5x1x1 401AL2-1 green ++ na na 1x1x0.5 2136AF2 green + na na 16431B 0.5x0.5x0.5 yellow + 571, 520 637, 575, 552, 503 16407 0.5x0.8x0.5 red-orange + 594, 577, 521 575, 503 16418 0.5x0.8x0.5 green ++ 520 602, 552, 503 16449C 0.5x0.5x0.5 red-orange + 592, 574, 439 637, 575, 503 16421 0.5x0.5x0.5 green 573, 520, 439 na 16449B 0.6x0.6x0.5 green + 573, 520, 439 na 16429B 0.5x0.5x0.5 green-yellow ++ 576, 520 na 16406 0.7x0.5x0.5 orange-yellow + 580, 520 na 16452 0.5x0.5 x0.5 pink + 617, 600, 576, 440 na 16447B 0.5x0.75 x0.75 blue-yellow 617, 600, 576, 440 na 16417 0.5x0.5x0.5 green + 520, 439 na Wawa meta- breccia diamonds 39c fragment* orange -525, 575 637, 575, 505 40c fragment* yellow-green -520, 442 503 58b fragment* yellow -578, 520 503 <MDL - below minimum detection limit; ++ very strong CL intensity; + medium , - low intensity; -- no CL data available na - not analyzed cubic diamonds are in bold * macrodiamond below <2 mm in all dimensions; exact original size unknown The table shows data on a subset of the fully characterized conglomerate diamonds; data on optical cathodoluminescence for 29 more diamonds is not listed  108  2000  meta-conglomerate macrodiamonds (>0.5 mm)  Intensity  1600  520 nm  1200  401AF 401BL 16396 16395 136AL  800 400 0  2500 meta-conglomerate  microdiamonds (<0.5 mm)  520 nm  Intensity  2000 1500 1000 575 nm  500 0  Intensity  500 meta-breccia  520 nm  macrodiamonds (>0.5 mm)  400  16418 16398A 16449C 16431B 16407  575 nm  300  39c  58b 40c  200 100 0  300  400  500 600 Wavelength (nm)  700  800  Figure 5-3 Representative cathodoluminescence (CL) spectra of meta-conglomerate and meta-breccia hosted diamonds. Labels of different spectra refer to sample numbers.  109  line (ZPL) at 503 nm and its sidebands at 512 and 520 nm (Figure 5-4). This ZPL and its sidebands are due to an H3 optical center (Davies, 1972; Zaitsev 2001). Some diamonds also show a broad maximum at 540–555 nm or at ~600 nm. In diamond sample 16398A, the peak at ~543 nm is sharp and intense. Six out of eight studied samples displayed a PL emittance peak at ~575 nm, which is sharp (five out of eight) or diffuse (sample 401 BL) and may be supplemented by sidebands at 587 and 601 nm (sample 16449C). The position of the ZPL line and its two sidebands matches the vibronic system ascribed to a neutrally charged N vacancy (NVo) optical center (Zaitsev, 2001). Five out of eight samples also show a peak at ~637 nm (Figure 5-4). The absence of this peak in CL suggests the peak is due to the NV– optical center, which is known to be only PL-active (Zaitsev 2001). Two of diamonds from unmetamorphosed source rocks displayed the vibronic system with ZPL at 503 nm, sidebands at 512, 525, 532 nm and a broad hump at ~610 nm. The sample with 20% B-centers showed smaller peaks that corresponded to positions of the 503 nm vibronic system and many peaks between 575 and 637 nm (Figure 5-5). 5.4 Luminescence of meta-breccia hosted diamonds 5.4.1 Cathodoluminescence of meta-breccia hosted diamonds Characterization of the meta-breccia hosted diamonds was not a part of the present study; cathodoluminescence (CL) results are reported by De Stefano et al (2006). They studied 69 samples and recorded (in descending abundance) orange-red (46%), yellow (28%), orange-green (10%), and green (6%) optical CL emittance, but none displayed the blue CL colour (Figure 5-2b). De Stefano et al (2007) suggest this higher CL wavelength emittance observed in the meta-breccia hosted diamonds is due to vacancy or B’ platelet defects on interstitial oxygen or carbon during an uncommon diamond-forming process. 5.4.2 Photoluminescence of meta-breccia diamonds For comparison purposes, this author had three diamonds from the meta-breccia 110  488 nm laser  16418  0 16398A  0 136AL  Intensity  0 16449C i  0  16407  0  401AF  0  401BL  0  16431B  0  39c  0  40c  0  58b  ii  0  490  510  530  570 590 550 Wavelength (nm)  610  630  650  Wavelength (nm) Figure 5-4 Liquid N2 temperature photoluminescence (PL) spectra for meta-conglomerate hosted diamonds (i) and meta-breccia hosted diamonds (ii). On PL intensity scale, gray tick marks outside of axis represent 10,000 arbitrary units, wheras black tick marks inside the plot denote 1,000 arbitary units. 111  488 nm laser IaA  Intensity  0 IaAB, 20%B  0 IaAB, 80%B  0  490  510  530  550  570 590 Wavelength (nm)  610  630  650  Figure 5-5 Liquid N2 temperature photoluminescence (PL) spectra diamonds with varied nitrogen aggregation from other source rocks (i.e. not from the meta-breccia or meta-conglomerate). On the PL intensity scale grey tick marks outside of the axis represent 10,000 arbitrary units.  112  rocks analyzed using photoluminescence (PL). These samples were a Type IaA (>10 ppm N in A aggregation) diamond and two Type IaAB (>10 ppm N in A and B aggregation) diamonds with yellow and orange CL emittance (Table 5-1), displaying a ZPL at 503 nm and sidebands at 512 and 520 nm (Figure 5-4). Diamond sample 39c also showed sharp peaks with ZPLs at 637 and 575 nm (with sidebands at 588 and 602 nm).  5.5 Interpretation Typically, naturally occurring octahedral Type Ia (containing >20 ppm N) diamonds exhibit blue colour under the CL beam and show highest intensity peaks at ~420 nm, although yellow is common as well (Bulanova, 1995; Ponahlo, 2000; De Stefano et al, 2006). This typical blue CL colour is generally controlled by light emission at ~430–450 and 480–490 nm (Lindblom et al, 2003), as in diamonds from the Jericho kimberlite and Rio Soriso placers (Figure 5-6). The wide CL peak at ~430–450 nm relates to the most common naturally occurring colour center in diamond, the N3 center (observed by a ZPL at 415 nm) comprised of a vacancy between three nitrogen atoms (Collins et al, 2005). The CL emission at ~490 nm results from slip traces (Collins et al, 2005). On a PL spectrum, naturally occurring Type Ia (containing >10 ppm N) diamonds display a ZPL at 503 nm, with sidebands at 512 and 520 nm, which is attributed to the H3 center (a pair of nitrogen atoms and a vacancy) (Clark et al, 1992). This center forms after diamond irradiation followed by annealing (Davies, 1976). There are several patterns one can observe in the luminescence data that were collected. First, the intensity of luminescence is an overall characteristic of a diamond suite. For example, meta-conglomerate hosted diamonds are generally more luminescent than meta-breccia hosted diamonds (compare their CL amplitudes on Figure 5-3). Second, the observed CL colours do not vary with N systematics of individual diamonds although emittance peaks do. Third, positions of PL emittance peaks are generally shifted with respect to CL peaks in the same samples and a prominent CL peak at 520 nm is not detected in PL. Overall, the majority of the meta-conglomerate and meta-breccia diamonds have distinct CL in comparison to diamonds found hosted in other types of rocks (e.g. primary kimberlite, placers). Diamonds from both the meta-conglomerate and 113  1.0 mm  600 500  0.5 mm  446 nm 487 nm  Intensity  400 300 200 100  0 300  400  500  600  Wavelength (nm)  700  800  Figure 5-6 Cathodoluminescence (CL) of diamonds found in unmetamorphosed rocks. a) Optical CL photographs of diamonds from the Jericho kimberlite, Nunavut, displaying the typical blue CL colour. b) CL spectrum of an alluvial diamond from Rio Soriso (Brazil). It is hypothesized that these diamonds were entrained in the mid-Cretaceous kimberlites and subsequently eroded into the Rio Soriso alluvial depostis (Hayman et al, 2005).  114  meta-breccia rocks, with few exceptions, do not contain the prevalent CL emittance at 415–440 nm attributed to a well-known N3 defect (Zaitsev 2001). The maximum CL emittance for these diamonds has shifted to higher wavenumbers, ranging from 490 to 670 nm. This has caused CL colours to change from blue, common to diamonds in kimberlites and placers, to green, yellow-orange, and red. Refer to Figures 5-3, 5-4, and 5-5 for comparison of CL and PL spectra. Spectral positions of sharp PL emittance lines are diagnostic of optical centers. The vibronic system with ZPL at 503 nm and its sidebands at 512 and 520 nm observed in PL spectra of all diamonds relates to the common H3 center ascribed to a pair of nitrogen atoms and a vacancy, which forms from annealing after radiation damage to a diamond (Davies, 1976; Clark et al. 1992). A wide “green” CL band peaking at ~520 nm is most likely due to this H3 vibronic system. These diamonds may also display PL peaks at ~575 and 637 nm, which are rare in diamonds from other types of rocks (i.e. not from the meta-breccia or meta-conglomerate). The latter, in contrast, show a wide PL maximum at ~605 nm.  115  Chapter 6: Discussion and conclusions 6.1 Meta-conglomerate origin The ~2700 Ma diamondiferous polymictic meta-conglomerate unconformably overlays the Michipicoten greenstone belt (MGB), which comprises of three mafic to felsic meta-volcanic cycles (Figure1-2). The meta-conglomerate formed in a successor basin that resulted from a late-stage rifting event of older continental crust, leading to an ocean basin and convergent margin (Ketchum et al, 2008), accompanied by subduction related intracratonic magmatism (Thurston, 2002). Successor basins are analogous to more recent pull-apart basins (Thurston and Chivers, 1990), which are sedimentary basins formed by strike-slip fault systems where offset leads to extension, resulting in topographic lows (Rahe et al, 1998) in which sediment is deposited. Examples of pullapart basins include the Dead Sea Basin, formed along the fault system between the Arabian and African plates (ten Brink and Ben-Avraham, 1989) and the Bohai Basin, located on the intraplate Tan–Lu (Tancheng–Lijiang) strike–slip fault zone in Northern China (Hu et al, 2000). The successor basins are filled with material derived from surrounding supracrustal lithologies, material from coeval rift-related volcanism (Mueller et al, 1994), and the first occurrence of detritus from slightly deeper crust tens of kilometers away, a consequence of uplift and erosion (e.g. Chown et al. 2002) during greenstone belt evolution. In accordance with this general pattern, Wawa-Abitibi successor basins in general display relatively local provenance for their lithic clasts (e.g. Mueller and Corcoran, 1998; Hyde, 1980) and are all <2700 Ma (Thurston and Chives, 1990). Greenstone belts of the Superior Province comprise two assemblages called Timiskaming and Keewatin types. The Keewatin assemblages are the greenstones after volcanic rocks, with ages usually >2700 Ma, (Thurston, 2002). A Timiskaming assemblage represents a successor basin and displays the following associated facies: intercalated pebble/cobble size dominated conglomerate-sandstone, sandstone-argillite, and pyroclastics (Hyde, 1980; Mueller et al, 1991). These facies are deposited on top of existing volcanic greenstones, making them the youngest formations of the cycle of a greenstone belt development in which they occur (Jirsa, 2000). Examples of other Timiskaming-type deposits are the Duparquet Formation, Southern Abitibi greenstone belt (Mueller et al, 1991) and the Midway sequence, western Wawa subprovince (Jirsa, 116  2000). Successor basins form in an extensional tectonic environment as a result of rifting. A different type of basin forms in a compressional tectonic setting, which is influenced by mountain building (DeCelles and Giles, 1996) and forms a foreland basin. These are more common in the Phanerozoic. The foreland basin results in deposition of similar type sedimentary and volcanic sequences, but represent deep marine to shallow marine deposits (i.e. flysch and molasse facies) which are much deeper than those found in Timiskaming deposits (Mueller et al, 1991). Less volcanism is an influence in foreland basin deposits (Burke, 1986). The Wawa meta-conglomerate represents a Timiskaming type assemblage (Sage, 1994) because it exhibits the typical clastic deposits (i.e. conglomerate, sandstone, etc; Mueller et al, 1994) formed in a subaerial to subaqueous facies (Wendland, 2010) and the predominance of volcanic clasts. The meta-conglomerate formed by a debris flow (Verley et al, 2007) in an alluvial fan – delta succession (Figure 6-1) displaying alluvial and turbiditic sequences with fan and braided stream sediments (Wendland, 2010). The meta-conglomerate contains clasts of local derivation dominated by granite or gabbro, or quartz and plagioclase. The foremost contributor is ~2700 Ma igneous rocks of Cycle 3 found surrounding the meta-conglomerate and continuing to the northeast (Lefebvre et al, 2005), comprising ~30-80% of clasts found within the metaconglomerate. The clasts are derived from mafic to felsic meta-volcanic rocks with various textures, and hypabyssal rocks of the same composition (Sylvester et al, 1987) including tholeiitic and vesicular pillowed flows (Williams et al, 1991). Nearby Archean felsic intrusive rocks and subvolcanic trondjemite and tonalite stocks (Sage et al, 1996) may have also contributed abundant quartz and plagioclase seen in clasts and the finegrained matrix. Neither lamprophyric nor metamorphic clasts are found within the diamondiferous meta-conglomerate. Due to lack of ultramafic rocks types within Cycle 3, chloritized clasts present within the meta-conglomerate are interpreted as altered peridotitic stocks mapped among Cycle 2 igneous rocks (Sage, 1994). Another rock type that must have come from Cycle 2 is chert, since there are no chert deposits found in Cycle 3 rocks. Cycle 2 contains bedded chert-magnetite-wacke near the top of its formation (Williams et al, 1991), which may have contributed to the chert-like clasts found in the meta-conglomerate. Local provenance for the majority of clasts follows the general pattern for repeated cycles of MGB development, where sedimentary rocks cap each of the three volcanic cycles and are predominantly sourced from volcanic rocks of the respective  117  LEGEND meta-sedimentary units  diamonds  mafic-intermediate meta-volcanics  diamond primary source rock: currently unknown  intermediate-felsic meta-volcanics intrusive rocks  Figure 6-1 Schematic diagram of emplacement model for the diamondiferous metaconglomerate. Figure not to scale. Modified from Miller, 2005.  118  cycle (Williams et al, 1991). This premise is also supported by detrital zircon studies that reflect the age of nearby volcanic units of the greenstone belt (Davis, 2002). Direction of sedimentary transport for detrital material in the meta-conglomerate is inferred to be from N to S-SW, based on the provenance of Archean sedimentary material in Wawa. The 2700 Ma Cycle 3 igneous rocks, which contributed a majority of detrital material forming the meta-conglomerate, are exposed to the northeast of the meta-conglomerate outcrops. Fralick et al (2006) describes sediment transport from the Onaman-Tashota terrane, now considered the Winnipeg River subprovince (Stott and Mueller, 2009), across the entire Quetico basin and into the McKellar Harbour Formation on the northern edge of the Wawa and Abitibi terranes due to the Quetico trench (Figure 1-1) having become over-full by 2696 Ma. The 2697 Ma age of some meta-conglomerate clasts correspond with contributions from far to the north. A barren younger (<2693.7 ± 1.5 Ma) meta-conglomerate found to the west (Pt Doré 13; Figure 2-1) contains clasts of gneiss and schist, unlike the diamondiferous unit. Presence of metamorphic clasts found in the younger unit indicate more distal sources for the successor basin material. This is also supported by ages of the detrital zircon grains (~3000 Ma). Rock units of this age exposed at the surface lie >100 km to the north (Benn and Moyen, 2008; Davis et al, 1995) or to the west (Ayer et al. 2006; Williams et al, 1992) from MGB. Presence of gneissic clasts in this barren meta-conglomerate is indicative of the terrane uplift that resulted in the exposures of the mid-crust.  6.2 Diamond origin 6.2.1 Cratonic vs. orogenic origin Diamond occurrences are found in cratonic settings (e.g. Nixon, 1995), orogenic settings (e.g. Sobolev and Shatsky, 1990), and at impact sites (e.g. Masaitis, 1998) and characteristics of each setting are reflected in diamond traits. Cratonic diamonds form under cratons and are brought up through the continentally stable crust by deeporiginating primary host rocks that are much younger than the crust, such as kimberlite or lamproite (Scott Smith, 1995). Orogenic diamonds are produced in ultra-high pressure terranes, such as a subduction zone and are brought to the surface by either tectonic uplift of the terrane or by non-kimberlitic magmas that are synchronous with the subduction (De Stefano et al, 2006). The fact that meta-conglomeate diamonds are not found in their primary host rock makes it difficult to determine the diamond origin. Impact diamonds  119  are not considered to be a possible source origin for the meta-conglomerate diamonds because there is no evidence of an Archean impact crater nearby. The diamonds occur within the Superior Craton and may therefore be cratonic. However, the age of the host volcanic rock is synorogenic and an orogenic setting should also be considered for these diamonds. Characterization of these diamonds is thus essential to constraint their origin. Abundant data on cratonic diamonds found in kimberlites can broadly categorize these crystals as populations of mostly single crystalline micro- and macrodiamonds with mostly octahedral morphologies (and smaller proportions of cuboids and aggregates), mostly colourless and yellow crystals, and displaying varying degrees of resorption (after Robinson, 1978; Boyd and Gurney, 1986; Bulanova, 1995; Field et al, 2008). Nitrogen contents for cratonic diamonds are usually <3500 ppm N with an average of ~200 ppm N, with mostly Type IaA-IaB (Cartigny et al, 2004 and references therein). Cathodoluminescence (CL) studies on diamonds found in cratonic settings usually display blue CL colour and possibly small percentages of yellow CL colour (Bulanova, 1995). A different set of characteristics is established for orogenic diamond originating within metamorphic terranes. These include the Kokchetav Massif, Kazakhstan (Sobolev and Shatsky, 1990; Chopin, 2003; Ogasawara, 2005), northern Qaidam, China (Yang et al, 2003), and Erzgebirge, Germany (Dobrzhinetskaya et al, 2006; Massonne and Nasdala, 2003). The orogenic diamonds typically are found as inclusions in other minerals, occur as microdiamonds, display mostly cuboid or irregular forms, and have lower aggregation contents as compared to cratonic diamonds (Cartigny et al, 2004; Gurney et al, 2010). The lower level of aggregation state indicates a lower mantle residence time experienced by these types of diamonds and the absence of resorption is consistent with the subsurface origin (De Corte et al, 1998). Their N contents are higher (~700-2400 ppm) and they are mostly Type Ib or IaA crystals (De Corte et al, 1998). An origin for the meta-breccia diamonds is unknown because this suite shows contradictory attributes that are unexplainable by cratonic or orogenic origins (De Stefano et al, 2006). As reported by De Stefano et al (2006), a cratonic source for the diamonds explains their low nitrogen contents, presence of resorbed and undeformed crystals, and a considerable residence mantle time (De Stefano et al, 2006). But the size distribution of meta-breccia crystals is biased towards microdiamonds and they all exhibit CL colours atypical for diamonds from cratonic settings, indicating a possible orogenic origin. Inclusion studies on the meta-breccia diamonds (De Stefano et al, 2006) 120  reveal the presence of plagioclase, a low-pressure mineral, which is inconsistent with deep diamond formation. The meta-conglomerate diamond characteristics match traits of cratonic diamonds. This is supported by the coarse diamond size distribution, a low average N content of ~250 ppm and a large number of complexly aggregated diamond types. The only trait inconsistent with this origin is the unusual CL colours displayed by these crystals. The origin of this atypical CL colour is explained later. 6.2.2 Did meta-conglomerate hosted diamonds originate from meta-breccia? The purpose of characterizing the Wawa meta-conglomerate diamonds is to confirm or reject the hypothesis that these diamonds are sourced from a proximal diamondiferous meta-breccia (Figure 2-1). Data published on meta-breccia diamonds were compared to the data of meta-conglomerate diamonds. The meta-conglomerate diamond suite contains 383 crystals and the meta-breccia suite contains 80 crystals. Described below, these two populations were compared using physical characteristics such as size, colour, crystal morphology (including resorption), and nitrogen (N) content and aggregation. 6.2.2.1 Constraints based on size and crystal growth forms Ninety-two percent of the meta-conglomerate diamonds are macrodiamonds (>0.5 mm in one dimension) and only 8% of crystals are microdiamonds (<0.5 mm in one dimension). In contrast, the meta-breccia diamond sizes are smaller with a much larger proportion of microdiamonds. De Stefano (2011) reports thousands of metabreccia microdiamonds in addition to the 46 microdiamonds reported in Lefebvre (2004). Thus, the size distribution of the meta-conglomerate and meta-breccia diamond populations is different. Comparison of crystal morphology of both suites are as follows (metaconglomerate% vs. meta-breccia%): octahedra and related forms (56% vs. 57%), cubic and related forms (12% vs. 11%), cubo-octahedral (7% vs. 8%), macle (3% vs. 8%), and undetermined (22% vs. 5%; De Stefano et al, 2006). Crystals with undetermined habit are grossly disproportionate between the two suites because the meta-breccia diamond histograms do not take broken crystals and fine aggregates into account. De Stefano et al (2006) also combined dodecahedra and octrahedra morphology classes together, which was applied for the meta-conglomerate diamond suite for comparison. 121  6.2.2.2 Constraints based on colour and cathodoluminescence The meta-conglomerate diamonds display colourless, yellow, grey, brown, green, and pink crystals. The meta-breccia diamonds do not contain any crystals that are green or pink, but show comparable percentages in regards to other colours (metaconglomerate% vs. meta-breccia%): colourless (64% vs. 50%), yellow (11%: 11%), grey (4%: 3%), brown (2%: 10%), black (1%: 3%) (meta-breccia data from De Stefano et al, 2006). Twenty-four percent of meta-breccia diamonds are described as having heterogeneous colour. Heterogeneous colour in diamond was only observed in metabreccia aggregates (Lefebvre, 2004; De Stefano et al, 2006). This is not observed in meta-conglomerate diamonds. Both the meta-conglomerate and meta-breccia display similar CL colours such as green, yellow, orange, pink, red-orange, and orange-green (Figure 5-2). These colours are controlled by emissions at ~520, ~585 nm and between ~585-640 nm. This shift to longer wavelengths, in comparison to diamonds in primary host rocks, is ascribed to the imprint of metamorphism, confirmed by studies of orogenic microdiamonds (Bruce et al, 2011). Because the CL colours of the meta-conglomerate and meta-breccia diamonds are similar, CL colour cannot discriminate between the two populations as being different. 6.2.2.3 Constraints based on resorption Degrees of resorption can be a way to distinguish different populations of diamond in different occurrences (Harris, 1992), such as the Mir kimberlite field producing diamonds with very low degrees of resorption (Gurney and Zweistra, 1995) or the Rio Soriso alluvial deposit containing ~90% diamonds that display resorbed surfaces (Hayman et al, 2007). Two different populations of diamonds, distinguished by varying degrees of resorption, have been reported to occur within a single kimberlite pipe as well (Gurney et al, 2004). Based on the concept that resorption is unique to a specific population, the resorption undergone by meta-conglomerate and meta-breccia diamonds can potentially differentiate these suites (Figure 6-2a). Using data on meta-breccia diamonds from De Stefano et al (2006), the comparison shows diamonds are categorized into (meta-conglomerate% vs. meta-breccia%) Class 1, severely resorbed (9% vs. 7%); Class 2-3, moderate resorption (15% vs. 9%); Class 4-5, slight resorption (28% vs. 66%); and Class 6, no resorption (42% vs. 10%). While the results are comparable for Classes 1 and 2-3, there is a disparity in Classes 4-5 and 6 between both groups, with metaconglomerate crystals displaying a larger majority of diamonds with no resorption.  122  Degree of Resorption  a  diamonds from metaconglomerate (n=383)  Class 1 (high)  diamonds from meta-breccia (n=80)  Class 2-3 (medium)  Class 4-5 (slight)  Class 6  (none)  Undetermined 0  Diamond Type  b  40  20  Frequency (%)  Type IaA  60  diamonds from metaconglomerate (n=72)  Type IaB  diamonds from meta-breccia (n=41)  Type IaAB Type II 0  20  Frequency (%)  40  Figure 6-2 Comparison of meta-conglomerate and meta-breccia hosted diamonds a) regarding resorption and b) diamond type. The meta-conglomerate contains lower degrees of resorption and higher N aggregation in contrast to the meta-breccia hosted diamonds.  123  The number of resorbed diamonds increases as diamond size decreases because surface area to mass ratio of crystals drops, resulting in faster dissolution of diamond (Harris, 1992 and references therein). This is consistent with smaller meta-breccia diamonds being more resorbed. Another factor possibly contributing to the difference in resorption between the two suites is volatile content of the transporting magma. It is shown by Fedortchouk (2004) and Kozai and Arima (2005) that volatiles present in the melt controls dissolution of diamonds the melt carries. 6.2.2.4 Constraints based on nitrogen systematics The two diamonds suites display dissimilar N contents. The meta-conglomerate% vs. meta-breccia% results are as follows (meta-breccia data from De Stefano et al, 2006): Type IaA (47% vs. 17%), Type IaB (6% vs. 0%), Type IaAB (36% vs. 49%), and Type II (11% vs. 34%) (Figure 6-2b). The meta-breccia diamonds generally contain less N content and fewer less aggregated crystals in comparison to meta-conglomerate diamonds. Meta-breccia diamonds show a bimodal distribution for %B aggregation, with most diamonds either containing <30%B or >60%B aggregation. Shifting temperaturetime histories is speculated to account for this bimodality (De Stefano et al, 2006), alluding to two different generations of diamond. Higher residence temperatures would cause earlier formed diamonds to show more N aggregation. A subsequent shift of the environment into lower temperatures, effectively increasing energy required to form Bcenters, would result in less aggregated crystals. A split in N aggregation types is not observed within the meta-conglomerate diamond population where most diamonds (77%) contain <40% fully aggregated nitrogen. Calculated residence times for both suites overlap each other, with meta-breccia diamonds residing at 1050-1150˚C (De Stefano, 2011) and meta-conglomerate diamonds at 1000-1200˚C. Even though these temperatures are calculated for different mantle residence times (300 Ma for meta-conglomerate and 180 Ma for meta-breccia), the effect of time on temperature is negligible. For example, changing residence time by 100 Ma only results in a ~15˚C difference in temperature. The temperature estimates cannot constrain whether the meta-conglomerate and meta-breccia diamonds are two distinct populations. 6.2.2.5 Constraints based on mineralogy and ages of host rocks Since the meta-conglomerate diamonds occur within a secondary host rock, any nearby diamondiferous primary host rock could potentially be the source. The metabreccia diamonds are hosted within calc-alkaline lamprophyre dykes and breccias, which 124  were emplaced approximately at the same time as Cycle 3 volcanics of the Michipicoten greenstone belt (MGB) (Lefebvre et al, 2005). Their proximal (~8km) location to the diamondiferous meta-conglomerate makes it a real possibility that meta-conglomerate diamonds were eroded out of the meta-breccia, transported away and incorporated into the meta-conglomerate forming there. Comparing published petrography data on the meta-breccia (Lefebvre et al, 2005) to the meta-conglomerate petrography shows that although both types of host rocks contain albite, chlorite, and epidote, amphiboles (specifically oscillatory hornblende and coarse actinolite) are only present within the meta-breccia (Lefebvre et al, 2005). Biotite also appears only in meta-breccia host rocks. The mineralogy of the meta-breccia is confirmed to be derived from calc-alkaline lamprophyres (Lefebvre et al, 2005; Wyman et al, 2006). The meta-conglomerate contains significant amounts of quartz, calcite and muscovite with traces of rutile, which are not present in the meta-breccia. The presence of quartz and muscovite indicates a more felsic detrital composition in metaconglomerate in comparison to meta-breccia host rocks. Metamorphic minerals replacing mafic minerals (e.g. actinolite) are only present within the meta-breccia. Thus, petrographic observations reject the presence of lamprophyric clasts in metaconglomerate. Relative ages of each diamond occurrence can constrain whether the metaconglomerate diamonds are sourced from the meta-breccia. In theory, if the metaconglomerate was younger than the meta-breccia, it is possible for the former to be derived from the latter, as material eroding out of older units create deposits younger in age relative to the original rock. If the meta-conglomerate was formed before the metabreccia, meta-conglomerate diamonds cannot be derived from the meta-breccia. Precise TIMS U-Pb dating on zircons shows the meta-conglomerate to be 2700.4±1.0 2697.2±1.8 Ma in age and becomes younger to the southwest. The meta-breccia, also younging to the southwest, is dated to be 2724± 24 Ma in the northeast to 2680±1 Ma in the southwest (De Stefano et al, 2006). One sample of meta-breccia (Pt 15-2; Figure 2-1) dated in this work shows a younger lower bound for the formation, 2619.1±1.8 Ma. Formation of the meta-breccia covers a wider range of times. It is presumed the metaconglomerate formation only had one episode, while the meta-breccia experienced episodic deposition over a range of times (Lefebvre et al, 2005). Geochronology cannot directly confirm the diamond populations are distinct from each other, but it cannot deny it either as the meta-breccia formation time encompasses the age range of formation for 125  the meta-conglomerate. 6.2.3 Interpretation Morphology, size distribution, and N content results are consistent with a cratonic origin for the meta-conglomerate diamonds. Meta-conglomerate diamonds may not be sourced from the proximal diamondiferous meta-breccia according to size, colour, morphology, and N systematics. The meta-conglomerate diamonds are coarser and display more diverse colours in comparison to the meta-breccia diamonds. Almost half of meta-conglomerate diamonds display no resorption, while the majority of meta-breccia diamonds are resorbed. Meta-conglomerate diamonds contain more nitrogen and are more aggregated. In addition, bimodal distribution of the N aggregation state is absent in the meta-conglomerate population, displaying a majority of Type IaA diamonds. Because physical attributes and N contents are reflective of a diamond’s genesis and post-genetic history (Robinson, 1978), the results obtained on the meta-conglomerate diamonds compared to meta-breccia data (De Stefano et al, 2006) indicate it is impossible for the two populations of diamonds to have undergone the same types of growth, resorption, and mantle residence temperature. Mineralogy of the host rocks support this model, as typical lamprophyric minerals actinolite and biotite do not occur in meta-conglomerate. The meta-breccia source rocks are inferred to be more mafic than the meta-conglomerate. Since the meta-conglomerate diamonds are not derived from the meta-breccia, another possible source rock must be proposed for meta-conglomerate diamonds. This Archean host rock may have completely eroded away. Geochemical work on the metaconglomerate by Wendland (2010) suggests a mafic to ultramafic source. The author used plots of immobile elements (e.g. Ni, Al, Cr) ratios to arrive at this conclusion. These mafic-ultramafic diamondiferous rocks could be kimberlite, lamproite, or ultramafic or calc-alkaline lamprophyre (Scott Smith, 1995; Lefebvre et al, 2005). Verley et al (2007) suggested kimberlite as the source rock based on the presence of kimberlite indicator minerals (e.g. pyrope, ilmenite, and chromite) found within the meta-conglomerate matrix. I cannot agree or reject this model, as I did not analyze compositions of heavy minerals in meta-conglomerates. If kimberlite is the source rock, the Michipicoten Greenstone Belt (MGB) must have experienced an episode of pre-2700 Ma Archean kimberlite magmatism in addition to the multiple emplacement episodes of the diamondiferous lamprophyre dykes. If kimberlite was not the primary host rock, other diamond-bearing magmas may be the source, such as lamprophyre or lamproite. This is supported by current models of diamond formation that postulate that early Archean 126  diamondiferous volcanic rocks were non-kimberlitic (Afanas’ev et al. 1998, 2009; Gurney et al, 2010). Kimberlites date back only to the Paleoproterozoic (2200 Ma and younger), but the oldest economic diamond deposit in a kimberlite is much younger, ~1200 Ma (Gurney et al. 2010 and references therein).  6.3 Origin of unusual cathodoluminescence Meta-conglomerate diamonds do not differ from meta-breccia diamonds in luminescence properties. Both of these suites show luminescence unlike that of cratonic diamonds. Because meta-conglomerate and meta-breccia diamonds are metamorphosed and cratonic diamonds are not, metamorphism could be the principal factor that affected the diamond luminescence. The greenschist metamorphism imposed on the meta-conglomerate and metabreccia is speculated to lead to the formation of the 575 and 637 nm peaks found in luminescent patterns. This is possible since metamorphism mildly anneals diamonds that resided in the upper crust and were subjected to irradiation. The source for irradiation of metamorphosed diamonds may be upper crustal K- and U-bearing minerals or waters since radioactive elements concentrate mostly in the upper crust (Rudnick and Gao, 2004). This is supported by the number of alluvial diamonds showing green coloration haloes of severe irradiation damage in comparison with kimberlite diamonds (Afanasiev et al, 2000). Subtle radiation damage may not necessarily be visible as coloration spots, but would create vacancies and interstitials in the diamond lattice. The most abundant radioactive isotopes of the upper crust (40K, 90Sr, and 238U) decay by emitting electrons (β-decay). Beta-rays can penetrate minerals for several millimeters depending on the beam energy and the mineral density. For example, beta-particles from the 90Sr decay would penetrate diamond for 3.5–4 mm (Knoll, 1989), which is sufficient to irradiate even coarse macrodiamonds (>0.5 mm in one dimension). The irradiation-added vacancies in the diamond crystal lattice would manifest themselves as luminescence optical centers only when diamonds are heated to ~500°C through metamorphism. Greenschist (2–10 kb, 350–520 °C) and amphibolite (2–12 kb, 520–700°C) facies metamorphism (Winter, 2001) would involve temperatures high enough to create the 575 127  and 637 nm optical centers. The luminescence of diamonds in low- and medium-grade metamorphic rocks can be preserved for billions of years (2700 Ma in Wawa) if the diamonds remain in the upper crust. If the crust is subducted and recycled into the mantle, high-T annealing at mantle temperatures (900–1300 °C) destroys the distinct CL and PL of metamorphosed diamonds. This occurs through enhanced annealing of vacancies, recombination of single substitutional N into A- and B-centers, and aggregation of nitrogen, destroying the NV– (ZPL at 637 nm) and NVo (ZPL at 575 nm) luminescence centers. The model proposed for the explanation of distinct luminescence of metamorphic Type Ia diamonds requires further testing and an experimental reproduction of the metamorphic effects. If the model is correct, the low abundance of octahedral Type Ia diamonds with blue CL colors in detrital diamond suites (such as the Wawa metaconglomerate) with an unknown source may be interpreted as a sign that they may have once been a part of a low- to medium-grade metamorphic terrane. Diamonds with the prevalent CL emission lines at 520–580 nm and PL peaks at 575 and 637 nm may have undergone metamorphism of at least the greenschist facies, while being included in primary volcanics or secondary collectors.  6.4 Conclusions •  The 170 m thick diamondiferous meta-conglomerate is a Timiskaming type deposit forming between 2700.4±1.0 Ma and 2697.2±1.8 Ma. Its matrix consists of albite, calcite, and chlorite, ± quartz, ± muscovite, ± rutile, ± epidote, ± Fesulfide and contains twenty-four clast types, which were classified into the following eight groups: igneous with subophitic texture; coarse-grained felsic; vesicular igneous; porphyritic mafic; porphyritic felsic; untextured volcanic; chert-like, unidentifiable clasts rich in chlorite, and opaques.  •  383 diamonds (<2 mm) extracted from the meta-conglomerate show octahedral, cuboid, cubo-octahedral, and twinned growth habits; most are unresorbed. According to nitrogen content and aggregation, these diamonds are classified as Type IaA, Type IaAB, Type II, and Type IaB. Their calculated mantle residence 128  temperature is 1000-1200˚C. •  Based on the above characteristics, the meta-conglomerate diamonds are cratonic in origin. A primary source is still unknown, speculated to be of mafic to ultramafic composition.  •  Proximal diamondiferous meta-breccia is not the source of meta-conglomerate diamonds. Meta-conglomerate diamonds display a coarser size distribution, more diamond colours, and larger proportion of unresorbed crystals.  •  Meta-breccia and meta-conglomerate diamonds display green, yellow, orange, pink, and red-orange cathodoluminescence (CL) colours, dissimilar to diamonds in unmetamorphosed rocks that show blue CL colour. This shift of CL results from presence of optical centers that may have formed due to irradiation of diamonds in the upper crust and annealing.  129  Bibliography Afanasiev, V. P., Yefimova, E. S., Zinchuk, N. N., and Koptil, V. I., 2000, Atlas of Morphology of Diamonds from Russian Sources: Novosibirsk, Russian Academy of Sciences, Siberian Branch, 293 p. Afanas'ev, V. P., Zinchuk, N. N., and Koptil, V. I., 1998, Diamond Polygenesis: Evidence for the Native Sources of Placers of the Northeastern Siberian Platform: Doklady earth sciences. Arima, M., and Kozai, Y., 2008, Diamond dissolution rates in kimberlitic melts at 13001500 ˚C in the graphite stability field: European Journal of Mineralogy, v. 20, p. 357-364. Ayer, J., Amelin, Y., Corfu, F., Kamo, S., Ketchum, J., Kwok, K., and Trowell, N., 2002, Evolution of the southern Abitibi greenstone belt based on U-Pb geochronology: autochthonous volcanic construction followed by plutonism, regional deformation and sedimentation: Precambrian Research, v. 115, p. 63-95. Ayer, J., Dubé, B., Goodfellow, W. D., Ross, P.-S., Bleeker, W., Taylor, B. E., Peter, J. M., Grunsky, E. C., Hillary, B., Thurston, P. C., Berger, B. R., Houlé, M., Beakhouse, G. P., Trowell, N. F., Snyder, D., McNicoll, V., Keating, P., Percival, J. A., MercierLangevin, P., Lauzière, K., Paradis, S., Goutier, J., Dion, C., Pilote, P., Legault, M., Monecke, T., Dumont, R., Brouillette, P., Gosselin, G., and Van Breemen, O., 2006, The Abitibi Subprovince: An update on the goals and preliminary results of the Precambrian Geoscience Section, Targeted Geoscience Initiative III and Deep Search Projects,: Summary of Field Work and Ohter Activities 2006: OGS Open File Report 6192, Geological Survey, Ontario, v. 4-1, p. 4-19. Barjon, J., Desfonds, P., Pinault, M. A., Kociniewski, T., Jomard, F., and Chevallier, J., 2007, Determination of the phosphorus content in diamond using cathodoluminescence spectroscopy: Journal of Applied Physics, v. 101, p. 113701-113701-4. Benn, K., and Moyen, J.-F., 2008, The Late Archean Abitibi-Opatica terrane, Superior Province: A modified oceanic Plateau, in Condie, K., and Pease, V., eds., When did Plate Tectonics Begin on Planet Earth? Volume Special Paper 440, Boulder, CO, Geological Society of America, p. 173-197. Boyd, F., and Gurney, J., 1986, Diamonds and the African lithosphere: Science, v. 232, p. 472-477. Boyd, S., Pineau, F., and Javoy, M., 1994, Modelling the Growth of Natural Diamonds: Chemical Geology, v. 116, p. 29-42. Bruce, L., Kopylova, M., Longo, M., Ryder, J., and Dobrzhinetskaya, L., 2011, Luminescence of diamonds from metamorphic rocks: American Mineralogist, v. 96, p. 14-22. 130  Bruton, E., 1970, Diamonds: London, N.A.G. Press Limited, 372 p. Bulanova, G. P., 1995, The Formation of Diamond: Journal of Geochemical Exploration, v. 53, p. 1-23. Burke, K., Kidd, W., and Kusky, T., 1986, Archean foreland basin tectonics in the Witwatersrand, South Africa: Tectonics, v. 5, p. 439-456. Cartigny, P., Chinn, I., Viljoen, K., and Robinson, D., 2004, Early proterozoic ultrahigh pressure metamorphism: evidence from microdiamonds: Science, v. 304, p. 853. Chopin, C., 2003, Ultrahigh-pressure metamorphism: tracing continental crust into the mantle: Earth and Planetary Science Letters. Chown, E. H., Harrap, R., and Moukhsil, A., 2002, The role of granitic intrusions in the evolution of the Abitibi belt, Canada: Precambrian Research, v. 115, p. 291-309. Clark, C. D., Collins, A. T., and Woods, G. S., 1992, Absorption and luminescence spectroscopy, in Field, J., ed., The properties of natural and synthetic diamond, Cambridge, University Press, p. 35-79. Collins, A., Connor, A., ly, C.-H., and Shareef, A., 2005, High-temperature annealing of optical centers in type-I diamond, Journal of Applied Physics, p. 1-10. Condie, K. C., 1981, Archean greenstone belts: Amsterdam; New York ,New York, Elsevier Scientific Pub. Co.; distributors for the U.S. and Canada, Elsevier NorthHolland, viii, 434 p. p. Covey, M., 1986, The evolution of foreland basins to steady state: evidence from the western Tiawan foreland basin, in Allen, P. A., and Homewood, P., eds., Foreland Basins, Oxford, Blackwell Scientific, p. 77-90. Davies, G., 1972, The effect of nitrogen impurity on the annealing of radiation damage in diamond: Journal of Physics C: Solid State Physics, v. 5, p. 2534. Davies, G., 1976, The A nitrogen aggregate in diamond-its symmetry and possible structure: Journal of Physics C-Solid State Physics, v. 9, p. L537. Davis, D. W., 2002, U-Pb geochronology of Archean metasediments in the Pontiac and Abitibi subprovinces, Québec, constraints on timing, provenance and regional tectonics: Precambrian Research, v. 115, p. 97-117. Davis, W. J., Machado, N., Gariepy, C., Sawyer, E. W., and Benn, K., 1995, U-Pb geochronology of the Opatica tonalite-gneiss belt and its relationship to the Abitibi greenstone belt, Superior Province, Quebec: Canadian Journal of Earth Sciences, v. 32, p. 113-127. De Corte, K., Cartigny, P., Shatsky, V., Sobolev, N., and Javoy, M., 1998, Evidence of fluid inclusions in metamorphic microdiamonds from the Kokchetav massif, northern Kazakhstan: Geochimica et Cosmochimica Acta, v. 62, p. 3765-3773.  131  De Stefano, A., 2011, Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds: Unpublished PhD thesis, University of British Columbia 1-211 p. De Stefano, A., Lefebvre, N., and Kopylova, M., 2006, Enigmatic diamonds in Archean calc-alkaline lamprophyres of Wawa, southern Ontario, Canada: Contributions to Mineralogy and Petrology, v. 151, p. 158-173. DeCelles, P., and Giles, K., 1996, Foreland basin systems: Basin Research, v. 8, p. 105123. Dobrzhinetskaya, L. F., Wirth, R., and Green, H. W., 2006, Nanometric inclusions of carbonates in Kokchetav diamonds from Kazakhstan: A new constraint for the depth of metamorphic diamond crystallization: Earth and Planetary Science Letters, v. 243, p. 8593. Evans, T., 1976, Diamonds: Contemporary Physics, v. 17, p. 45-70. Evans, T., 1992, Aggregation of nitrogen in diamonds, in Field, J., ed., The properties of natural and synthetic diamond., New York, Academic, p. 259-290. Evans, T., Qi, Z., and Maguire, J., 1981, The stages of nitrogen aggregation in diamond: Journal of Physics C: Solid State Physics, v. 14, p. L379. Fallon, P. J., Brown, L. M., Barry, J. C., and Bruley, J., 1995 Nitrogen determination and characterization in natural diamond platelets: Philosophical Magazine A-Physics of Condensed Matter Structure Defects and Mechanical Properties, v. 72, p. 21-37. Fedortchouk, Y., Canil, D., and Carlson, J. A., 2004, Relationship between Diamond Dissolution Features, Oxygen Fugacity and Temperatures of Lac de Gras Kimberlite Magmas, Fall Meeting 2004, San Francisco, American Geophysical Union. Fedortchouk, Y., Canil, D., and Semenets, E., 2007, Mechanisms of diamond oxidation and their bearing on the fluid composition in kimberlite magmas: American Mineralogist, v. 92, p. 1200. Fedortchouk, Y., Matveev, S., and Carlson, J. A., 2010, H2O and CO2 in kimberlitic fluid as recorded by diamonds and olivines in several Ekati Diamond Mine kimberlites, Northwest Territories, Canada: Earth and Planetary Science Letters, v. 289, p. 549-559. Field, J. E., 1992, Table of Properties, in Field, J. E., ed., The Properties of Natural and Synthetic Diamond, London, Academic press, p. 667-699. Field, M., Stiefenhofer, J., Robey, J., and Kurszlaukis, S., 2008, Kimberlite-hosted diamond deposits of southern Africa: A review: Ore Geology Reviews, v. 34, p. 33-75. Fisher, D., 2009, Brown diamonds and high pressure high temperature treatment: Lithos, v. 112, p. 619-624.  132  Fralick, P., Purdon, R. H., and Davis, D. W., 2006, Neoarchean trans-subprovince sediment transport in southwestern Superior Province; sedimentological, geochemical, and geochronological evidence: Canadian Journal of Earth Sciences, v. 43, p. 1055-1070. Fritsch, E., 1998, The nature of color in diamond, in Harlow, G. E., ed., The Nature of Diamonds, Cambridge, Cambridge University Press, p. 23-47. Fujita, N., Jones, R., and Öberg, S., 2009, Large spherical vacancy clusters in diamondOrigin of the brown colouration?: Diamond And Related Materials, v. 18, p. 843-845. Gaft, M., Reisfeld, R., and Panczer, G., 2005, Modern Luminescence Spectroscopy of Minerals and Materials: Berlin/Heidelberg, Springer. Gerstenberger, H., and Haase, G., 1997, A highly effective emitter substance for mass spectrometric Pb isotope ratio determinations: Chemical Geology, v. 136, p. 309-312. Goodwin, A., 1962, Structure, stratigraphy, and origin of iron formations, Michipicoten area, Algoma District, Ontario, Canada: Geological Society of America Bulletin, v. 73, p. 561. Gurney, J., Helmstaedt, H., and Moore, R. O., 1993, A review in the use and application of mantle mineral geochemistry in diamond exploration: Pure and Applied Chemistry, v. 65, p. 2423-2442. Gurney, J., Helmstaedt, H., Richardson, S. H., and Shirey, S., 2010, Diamonds through time: Economic Geology, v. 105, p. 689-712. Gurney, J. J., 1989, Diamonds, in Ross, J., ed., Kimberlites and Related Rocks, Blackwell, Carlton, Geol. Soc. Special Publication, p. 966-989. Gurney, J. J., Hildebrand, P. R., Carlson, J. A., Fedortchouk, Y., and Dyck, D. R., 2004, The morphological characteristics of diamonds from the Ekati property, Northwest Territories, Canada: Lithos, v. 77, p. 21-38. Gurney, J. J., and Zweistra, P., 1995, The Interpretation of the Major-Element Compositions of Mantle Minerals in Diamond Exploration: Journal of Geochemical Exploration, v. 53, p. 293-309. Hanley, P. L., Kiflawa, I., and Lang, A. R., 1977, On Topographically Identifiable Sources of Cathodoluminescence in Natural Diamonds: Philosophical Transactions of the Royal Society of LondonSeries A: Mathematical and Physical Sciences, , v. 284, p. 329368. Harris, J., 1987, Recent physical, chemical, and isotopic research of diamond, in Nixon, P. H., ed., Mantle Xenoliths, Chichester, John Wiley & Sons, p. 477-500. Harris, J. W., 1992, Diamond geology, in Field, J., ed., Properties of Natural and Synthetic Diamond, London, Academic Press, p. 345-392.  133  Harris, J. W., Hawthorne, J. B., Oosterveld, M. M., and Wehmeyer, E., 1975, A classification scheme for diamond and a comparative study of South African diamond characteristics: Physics and Chemistry of The Earth, v. 9, p. 765-772, IN13, 773-783. Hayman, P., Kopylova, M., and Kaminsky, F., 2005, Lower mantle diamonds from Rio Soriso (Juina area, Mato Grosso, Brazil): Contributions to Mineralogy and Petrology, v. 149, p. 430-445. Henderson, B., and Imbusch, G., 1989, Optical Spectroscopy of Inorganic Solids: Oxford, Clarendon Press, 645 p. Hounsome, L., Jones, R., Martineau, P., Fisher, D., Shaw, M., Briddon, P., and Öberg, S., 2007, Role of extended defects in brown colouration of diamond: physica status solidi (c), v. 4, p. 2950-2957. Hu, S., O'Sullivan, P., Raza, A., and Kohn, B., 2001, Thermal history and tectonic subsidence of the Bohai Basin, northern China: a Cenozoic rifted and local pull-apart basin: Physics of the Earth and Planetary Interiors, v. 126, p. 221-235. Hyde, R. S., 1980, Sedimentary facies in the Archean Timiskaming Group and their tectonic implications, Abitibi greenstone belt, Northeastern Ontario, Canada: Precambrian Research, v. 12, p. 161-195. Jirsa, M., 2000, The Midway sequence: a Timiskaming-type, pull-apart basin deposit in the western Wawa subprovince, Minnesota: Canadian Journal of Earth Sciences, v. 37, p. 1-15. Kaiser, W., and Bond, W., 1959, Nitrogen, a major impurity in common type I diamond: Physical Review, v. 115, p. 857-863. Ketchum, J., Ayer, J., van Breemen, O., Pearson, N., and Becker, J., 2008, Pericontinental Crustal Growth of the Southwestern Abitibi Subprovince, Canada--U-Pb, Hf, and Nd Isotope Evidence: Economic Geology, v. 103, p. 1151. Kitamura, M., Hosoya, S., and Sunagawa, I., 1979, Re-investigation of the re-entrant corner effect in twinned crystals: Journal of Crystal Growth, v. 47, p. 93-99. Klein, C., and Dutrow, B., 2007, Manual of Mineral Science: New Jersey, John Wiley & Sons, 675 p. Knoll, G. F., 1989, Radiation detection and measurement, 2nd ed.: New York, Wiley, 350 p. Kozai, Y., and Arima, M., 2005, Experimental study on diamond dissolution in kimberlitic and lamproitic melts at 1300-1420 {degrees} C and 1 GPa with controlled oxygen partial pressure: American Mineralogist, v. 90, p. 1759. Lang, A., Moore, M., and Walmsley, J., 1992, Diffraction and imaging studies of diamond, in Field, J., ed., The properties of natural and synthetic diamond, Cambridge, University Press, p. 215-257. 134  crystallisation of diamond: Journal of Crystal Growth, v. 23, p. 151-153. Lang, A. R., Bulanova, G. P., Fisher, D., Furkert, S., and Sarua, A., 2007, Defects in a mixed-habit Yakutian diamond: Studies by optical and cathodoluminescence microscopy, infrared absorption, Raman scattering and photoluminescence spectroscopy: Journal of Crystal Growth, v. 309, p. 170-180. Lefebvre, N., 2004, Petrology, volcanology, and diamonds of Archean calc-alkaline lamprophyres, Wawa, Ontario, Canada: Unpublished M.Sc. thesis, University of British Columbia 1-282 p. Lefebvre, N., Kopylova, M., and Kivi, K., 2005, Archean calc-alkaline lamprophyres of Wawa, Ontario, Canada: Unconventional diamondiferous volcaniclastic rocks: Precambrian Research, v. 138, p. 57-87. Lindblom, J., Holsa, J., Papunen, H., Hakkanen, H., and Mutanen, J., 2003, Differentiation of natural and synthetic gem-quality diamonds by luminescence properties: Optical Materials, v. 24, p. 243-251. Lipatov, E. I., Avdeev, S. M., and Tarasenko, V. F., 2010, Photoluminescence and optical transmission of diamond and its imitators: Journal of Luminescence, v. 130, p. 21062112. Ludwig, K. R., 2003, Isoplot 3.00, A Geochronological Toolkit for Microsoft Excel, University of California at Berkely, kludwig@bgc.org. Magee, C., and Taylor, W. R., 1998, Constraints from luminescence on the history and origin of carbonado, in Gurney, J. J., Gurney, J. L., Pascoe, M. D., and Richardson, S. H., eds., VII International Kimberlite Conference, Vol. 2, Cape Town, South Africa, Red Roof Designs, p. 529-532. Marfunin, A. S., 1979, Spectroscopy, luminescence and radiation centers in minerals: Berlin, Springer-Verlag, 352 p. Marshall, D. J., and Mariano, A. N., 1988, Cathodoluminescence of geological materials : an introduction: Boston, Allen & Unwin, xiv, 146 p. p. Masaitis, V. L., 1998, Popigai crater: Origin and distribution of diamond-bearing impactites: Meteoritics & Planetary Science, v. 33, p. 349-359. Massonne, H. J., and Nasdala, L., 2003, Characterization of an early metamorphic stage through inclusions in zircon of a diamondiferous quartzofeldspathic rock from the Erzgebirge, Germany: American Mineralogist, v. 88, p. 883-889. McCallum, M. E., Huntley, P. M., Falk, R. W., and Otter, M. L., 1994, Morphological, resorption and etch feature trends of diamonds from kimberlite populations within the Colorado-Wyoming state line district, USA. In: Meyer HOA, Leonardos O (eds): Proceedings of the 5th international kimberlite conference, Brasilia, Brazi, v. Companhia de Pesquisa de Recursos Minerals, p. 78-97. 135  Mcgill, G. E., 1992, Structure and Kinematics of a Major Tectonic Contact, Michipicoten Greenstone-Belt, Ontario: Canadian Journal of Earth Sciences, v. 29, p. 2118-2132. Mendelssohn, M. J., and Milledgea , H. J., 1995, Morphological Characteristics of Diamond Populations in Relation to Temperature-Dependent Growth and Dissolution Rates: International Geology Review, v. 37, p. 285-312. Miller, A., 2005, A contribution to the geology of the diamondiferous metasedimentary rocks: sedimentology, stratigraphy, detrital mineralogy and conceptual model, Leadbetter Property, Chabanel Township, Michipicoten Greenstone Belt, Superior Province, Ontario, using petrography-ore microscopy-scanning electron microscopy: Dianor Resources, Inc, v. Company Report, p. 1-108. Miller, C., 2011, personal communication. Mueller, W., Donaldson, J., Dufresne, D., and Rocheleau, M., 1991, The Duparquet Formation: sedimentation in a late Archean successor basin, Abitibi greenstone belt, Quebec, Canada: Can. J. Earth Sci, v. 28, p. 1394-1406. Mueller, W., and Corcoran, P. L., 1998, Late-orogenic basins in the Archaean Superior Province, Canada: characteristics and inferences: Sedimentary geology, v. 120, p. 177203. Mueller, W., Donaldson, J. A., and Doucet, P., 1994, Volcanic and tectono-plutonic influences on sedimentation in the Archaean Kirkland Basin, Abitibi greenstone belt, Canada: Precambrian Research, v. 68, p. 201-230. Nixon, P., 1995, The morphology and nature of primary diamondiferous occurrences: Journal of Geochemical Exploration, v. 53, p. 41-71. Ogasawara, Y., 2005, Microdiamonds in ultrahigh-pressure metamorphic rocks: Elements, v. 1, p. 91. Orlov, Y. L., 1977, The Mineralogy of Diamond: New York, John Wiley & Sons, 235 p. Pagel, M., Barbin, V., Blanc, P., and Ohnenstetter, D., 2000, Cathodoluminescence in geosciences: an introduction, in M. Pagel, V. Barbin, Blanc, P., and Ohnenstetter, D., eds., Cathodoluminescence in Geosciences, Berlin, Springer, p. 1-509. Pandeya, D., and Tolansky, S., 1961, Micro-disk Patterns on Diamond Dodecahedra: Proceedings of the Physical Society, v. 78, p. 12. Percival, J., McNicoll, V., and Bailes, A., 2006, Strike-slip juxtaposition of ca. 2.72 Ga juvenile arc and> 2.98 Ga continent margin sequences and its implications for Archean terrane accretion, western Superior Province, Canada: Canadian Journal of Earth Sciences, v. 43, p. 895-927. Perkins, D., 2002, Mineralogy: 2nd Edition: New Jersey, Prentice Hall, 483 p.  136  Polat, A., and Kerrich, R., 2001, Geodynamic processes, continental growth, and mantle evolution recorded in late Archean greenstone belts of the southern Superior Province, Canada: Precambrian Research, v. 112, p. 5-25. Ponahlo, J., 2000, Cathodoluminescence as a Tool in Gemstone Identification, in Pagel, M., Barbin, V., Blanc, P., and Ohnenstetter, D., eds., Cathodoluminescence in Geosciences, Heidelberg, Springer, p. 479-500. Rahe, B., Ferrill, D., and Morris, A., 1998, Physical analog modeling of pull-apart basin evolution: Tectonophysics, v. 285, p. 21-40. Remond, G., Phillips, M., and Roques-Carmes, C., 2000, Importance of Instrumental and Experimental Factors on the Interpretation of Cathodoluminescence Data from Wide Band Gap Materials, in M. Pagel, V. Barbin, Blanc, P., and Ohnenstetter, D., eds., Cathodoluminescence in Geosciences, Berlin, Springer, p. 1-509. Rice, R. J., and Donaldson, J. A., 1992, Sedimentology of the Archean Dore Metasediments, Arliss Lake Area, Southern Michipicoten Greenstone-Belt, Superior Province: Canadian Journal of Earth Sciences, v. 29, p. 2558-2570. Robinson, D., 1978, The Characteristics of Natural Diamond and their Interpretation: Minerals Science and Engineering, v. 10, p. 55-72. Robinson, D., 1979, Surface textures and other features of diamonds: Unpub. Unpublished Ph.D. thesis, University of Cape Town 1-245 p. Roddick, J. C., 1987, Generalized numerical error analysis with application to geochronology and thermodynamics: Geochimica et Cosmochimica Acta, v. 51. Rondeau, B., Fritsch, E., Moore, M., Thomassot, E., and Sirakian, J., 2007, On the growth of natural octahedral diamond upon a fibrous core: Journal of Crystal Growth, v. 304, p. 287-293. Rudnick, R. L., and Gao, S., 2004, Composition of the continental crust.: Treatise on Geochemistry: The Crust: Oxford, Elsevier, 1-64 p. Sage, R. P., Lightfoot, P., and Doherty, W., 1996, Bimodal cyclical Archean basalts and rhyolites from the Michipicoten (Wawa) greenstone belt, Ontario: geochemical evidence for magma contributions from the asthenospheric mantle and ancient continental lithosphere near the southern margin of the Superior Province: Precambrian Research, v. 76, p. 119-153. Sage, R. P., and Ontario. Ministry of Northern Development and Mines., 1994, Geology of the Michipicoten greenstone belt, Toronto, Ministry of Northern Development and Mines, Mines and Minerals Division. Scoates, J. S., and Friedman, R. M., 2008, Precise age of the platiniferous Merensky reef, Bushveld Complex, South Africa, by the U-Pb zircon chemical abrasion ID-TIMS technique: Economic Geology, v. 103, p. 465-471. 137  Scott Smith, B. H., 1995, Petrology and Diamonds: Exploration and Mining Geology, v. 4, p. 127-140. Seal, M., 1965, Structure in diamonds as revealed by etching: American Mineralogist, v. 50, p. 105-123. Smith, E. M., 2009, Survival of Brown Colour in Diamond During Storage in the Subcontinental Lithospheric Mantle: Unpub. Unpublished M.Sc. thesis, Queen’s University 1-127 p. Sobolev, N. V., and Shatsky, V. S., 1990, Diamond inclusions in garnets from metamorphic rocks: a new environment for diamond formation: Nature, v. 343, p. 742746. Stachel, T., 2007, Diamond, in Groat, L. A., ed., Geology of Gem Deposits, Yellowknife, Northwest Territories, Mineralogical Association of Canada Short Course 37, p. 1-22. Stefano, A., Lefebvre, N., and Kopylova, M., 2006, Enigmatic diamonds in Archean calcalkaline lamprophyres of Wawa, southern Ontario, Canada: Contributions to Mineralogy and Petrology, v. 151, p. 158-173. Stott, G., and Mueller, W., 2009, Superior Province: The nature and evolution of the Archean continental lithosphere: Precambrian Research, v. 168, p. 1-3. Sunagawa, I., 1984a, Growth of crystals in nature, in Sunagawa, I., ed., Materials Science of the Earth's Interior, Tokyo, Terra Scientific Publishing Company (TERRAPUB), p. 63105. Sunagawa, I., 1984b, Morphology of natural and synthetic diamond crystals, in Sunagawa, I., ed., Materials Science of the Earth's Interior, Tokyo, Terra Scientific Publishing Company (TERRAPUB), p. 303-330. Sylvester, P. J., Attoh, K., and Schulz, K. J., 1987, Tectonic Setting of Late Archean Bimodal Volcanism in the Michipicoten (Wawa) Greenstone-Belt, Ontario: Canadian Journal of Earth Sciences, v. 24, p. 1120-1134. Taylor, W., Jaques, A., and Ridd, M., 1990, Nitrogen-defect aggregation characteristics of some Australian diamonds - Time-temperature constraints on the source regions of pipe and alluvial diamonds: American Mineralogist, v. 75, p. 1290-1310. ten Brink, U., and Ben-Avraham, Z., 1989, The anatomy of a pull-apart basin: Seismic reflection observations of the Dead Sea basin: Tectonics, v. 8, p. 333-250. Thirlwall, M. F., 2000, Inter-laboratory and other errors in Pb isotope analyses investigated using a 207Pb–204Pb double spike: Chemical Geology, p. 299-322. Thurston, P. C., 2002, Autochthonous development of Superior Province greenstone belts?: Precambrian Research, v. 115, p. 11-36.  138  Thurston, P. C., and Chivers, K. M., 1990, Secular variation in greenstone sequence development emphasizing Superior Province, Canada: Precambrian Research, v. 46, p. 21-58. Titkov, S., Shigley, J., Breeding, C., Mineeva, R., Zudin, N., and Sergeev, A., 2008, Natural-color purple diamonds from Siberia: Gems & Gemology, v. 44, p. 56-64. Titkov, S., Zudin, N., Gorshkov, A., Sivtsov, A., and Magazina, L., 2003, An Investigation into the Cause of Color in Natural Black Diamonds from Siberia: Gems & Gemology, v. 39, p. 200-209. Titus, E., Ali, N., Cabral, G., Madaleno, J., Neto, V., Gracio, J., Ramesh Babu, P., Sikder, A., Okpalugo, T., and Misra, D., 2006, Nitrogen and hydrogen related infrared absorption in CVD diamond films: Thin solid films, v. 515, p. 201-206. Turek, A., Smith, P. E., and Van Shmus, W. R., 1982, Rb-Sr and U-Pb ages of volcanics and granite emplacement in the Michipicoten Belt, Wawa, Ontario: Earth, v. 19, p. 16081626. Verley, C. G., 2006, Technical Report on the Leadbetter Diamond Project, Due Diligence Diamond Sampling Program, Leadbetter Diamond Project, Richmond, Dianor Resources Inc, p. 1-42. Verley, C. G., D'Amours, C., and Martel, B.-O., 2007, Preliminary Tonnage Estimate for the Diamondiferous Conglomerates of the Leadbetter Diamond Project, Leadbetter Diamond Project, Quebec, Dianor Resources Inc, p. 1-90. Walker, G., 1985, Mineralogical Applications of Luminescence Techniques, in Berry, F. J., and Vaughn, D. J., eds., Chemical Bonding and Spectroscopy in Mineral Chemistry, London, Chapman and Hall, p. 103-140. Walker, G., 2000, Physical parameters for the identification of luminescence centres in minerals, in Pagel, M., Barbin, V., Blanc, P., and Ohnenstetter, D., eds., Cathodoluminescence in Geosciences, Berlin, Springer, p. 514. Wang, W., Smith, C., Hall, M., Breeding, C., and Moses, T., 2005, Treated-Color Pinkto-Red Diamonds from Lucent Diamonds Inc: Gems & Gemology, v. 41, p. 6-19. Wendland, C., 2010, Diamondiferous Mass-Flow and Traction Current Deposits in a Neoarchean Fan Delta, Wawa Area, Superior Province: Unpublished M.Sc. thesis, p. 1136. Williams, H. R., Stott, G. M., Heather, K. B., Muir, T. L., and Sage, R. P., 1991, Wawa Subprovince. In: Thurston PC, Williams HR, Sutcliffe RH, Stott GM (eds) Geology of Ontario, special volume 4, v. Ministry of Northern Development and Mines, Ontario Geological Survey, Sudbury, p. 485–538. Williams, H. R., Stott, G. M., and Thurston, P. C., 1992, Tectonic evolution of Ontario: summary and synthesis. Part 1: Revolution in the Superior Province, in Thurston, P. C., 139  Williams, H. R., Sutcliffe, R. H., and Stott, G. M., eds., Geology of Ontario, Volume Special Volume 4, Part 2, Geological Survey of Ontario, p. 1255-1294. Winter, J. D., 2001, An Introduction to Igneous and Metamorphic Petrology: New Jersey, Prentice-Hall Inc. Woods, G. S., 1986, Platelets and the infrared absorption of type Ia diamonds: Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, v. 407, p. 219-238. Wyman, D. A., Ayer, J. A., Conceicao, R. V., and Sage, R. P., 2006, Mantle processes in an Archean orogen: Evidence from 2.67 Ga diamond-bearing lamprophyres and xenoliths: Lithos, v. 89, p. 300-328. Yang, J., Xu, Z., Dobrzhinetskaya, L., Green, H., Pei, X., Shi, R., Wu, C., Wooden, J., Zhang, J., Wan, Y., and Li, H., 2003, Discovery of metamorphic diamonds in central China: an indication of a > 4000-km-long zone of deep subduction resulting from multiple continental collisions: Terra Nova, v. 15, p. 370-379. Yelisseyev, A., Lawson, S., Sildos, I., Osvet, A., Nadolinny, V., Feigelson, B., Baker, J. M., Newton, M., and Yuryeva, O., 2003, Effect of HPHT annealing on the photoluminescence of synthetic diamonds grown in the Fe-Ni-C system: Diamond and Related Materials, v. 12, p. 2147-2168. Zaitsev, A. M., 2001, Optical properties of diamond : a data handbook: Berlin ; New York, Springer, xvii, 502 p.  140  Appendix A: Field descriptions  141  142  143  144  145  146  147  148  149  150  151  152  153  154  155  156  157  158  159  160  Appendix B: Petrographic descriptions  161  Petrographic microscopy descriptions T/S #  Sample #  1  170.67  %Modal Mineral Mineral Description meta-conglomerate: coarse texture, clast supported with large clasts avg 9x5 mm in length; all elongate in one direction, carbonate is present throughout slide in anhedral shapes (~0.05x0.05 mm) in all clasts up to 15% 25  clast 2  mafic effusive clast with subophitic texture  20 20  clast 9 clast 19  porphyritic felsic hypabyssal clast chert  4 2  clast 1 clast 21  mafic hypabyssal clast with subophitic texture globular ultra-mafic clast encompassing plagioclase laths  1  grain 3  untwinned plagioclase grain  1  grain 3  single quartz grain  clast 18 clast 20 groundmass  cryptocrystalline felsic volcanic clast carbonate-rich chert see description below  1 1 25 clast mineralogy: 75%  clast 2  clast 9  mafic effusive clast with subophitic texture: thin; these plagioclase crystals are thin laths (~4x2 mm), very large clasts (one is 6x4 mm and another is 2 mm and continues off the field of view) testing for highlights low relief, 1st O yellow colours, simple twinning visible; 21 plagioclase euhedral laths (~0.2x0.01 mm) plagioclase or anhedral crystals occurring between yellow plag laths 3 quartz (~0.1x0.1 mm) 1 opaques black dust, occurs ubiquitously throughout clast porphyritic felsic hypabyssal clast; ~8x4 mm in size, oblong plagioclase  low interference colours with low relief; fine-grained form that makes up the groundmass within this clast  5  plagioclase  low interference colours with low relief; porphyroclast, ~0.8x0.5 mm in size with oscillatory extinction  1  black opaque  black dust, occurs ubiquitously throughout clast  15  clast 19  chert; flattened oblong shape, 17x8 mm and continues out of field of view plagioclase or 20 quartz fine-grained plagioclase or quartz with a mosaic-like texture These clasts contains up to 10% chlorite flakes.  clast 1  mafic hypabyssal clast with subophitic texture; ~3.5x2 mm in size, elongate low relief, 1st O yellow colours, simple twinning visible; 2 plagioclase euhedral laths (~0.8x0.3 mm) plagioclase or anhedral crystals occurring between yellow plag laths 1 quartz (~0.1x0.1 mm) 1 opaques black dust, occurs ubiquitously throughout clast  clast 21  globular ultra-mafic clast encompassing plagioclase laths (~4x1.5 mm); flattened with tapered points  1.5  chlorite  very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other characteristics  162  T/S # 1  Sample #  %Modal  Mineral  Mineral Description  170.67 (continued) 0.5 grain 3  1  muscovite  low relief with high interference colours; small laths ~0.04x0.01 mm and flakes, up to 2%  plagioclase  low interference colours and low relief; anhedral equant grains (~0.4 mm in size), untwinned  grain 3  single quartz grain; up to 0.4 mm in size low interference colours with low relief; small aggregates 1 quartz of a few crystals or single crystals Most of these clasts are too small to obtain interference figures, but are presumed to be representative of the clasts that were able to be determined as biaxial or uniaxial. Occasional slivers of chlorite present.  clast 18  cryptocrystalline felsic volcanic clast plagioclase or low interference colours and low relief; fine grained plag or 0.7 quartz qtz that makes up the groundmass of this clast  clast 20  0.05  chlorite  green in PPL; small flakes  0.25  dark mass  dark "fuzzy" texture that is present in lenses, seen in PPL which is completely dark in XPL  carbonate-rich chert, ~16x8 cm variable relief and distinctive interference colours; up to 55 carbonate ~0.2 mm in size plagioclase or low interference colours and low relief; fine grained plag or 45 quartz qtz that makes up the groundmass of this clast  fine grained matrix 25%: unusually biotite-rich plagioclase or low interference colours with low relief; anhedral indistinct 9 quartz crystals making up majority of the groundmass variable relief and distinctive interference colours; irregular aggregates or single crystals (~0.1x0.4 mm in size), single 7 carbonate crystals occur in irregular shapes, some are poikilitic low relief with distinct interference colours; small flakes 2 muscovite randomly oriented throughout brown pleiochroic in PPL with distinct interference colours; laths and hexagonal cross sections visible, not preferentially 2 biotite oriented but wrap around clasts green in PPL; small flakes and sprinkles present, evenly 3 chlorite distributed 2 opaques little black opaques, anhedral  163  T/S #  Sample #  2  452.3  %Modal Mineral Mineral Description bedded and graded argillite: this slide is divided into two sides because of an abrupt change at the center (unconformity?): a finer and coarser side (the finer side is on the same side as the sample number)  coarse side 50%: graded bed fining towards center of slide 15  plagioclase or quartz  14  muscovite  9  plagioclase  low interference colours and low relief; fine grained infill between larger grains, low relief and high interference colours; fine grained fibrous muscovite aligned in one direction; occasional large crystal of muscovite ~0.05x0.04 mm (cross section?) 1st order yellow interference colours and low relief; small ~0.2 mm anhedral crystals, flattened; size decreases as fining increases, faint twinning seen  8  quartz  low grey interference colours and low relief; small ~0.3x0.2 mm grains, flattened with diffuse boundaries; size decreases as fining increases  2  chlorite  green in PPL with high relief; flakes througout section, randomly aligned  black opaques  randomly scattered of varying sizes throughout section, 0.04-0.12 mm in size  2  fine side 50%: mica-rich bed/organic-rich bed (?), and massive bed massive bed 35% plagioclase or quartz  low relief and low interference colours; indistinct crystals throughout massive bed, some single grains ~0.02 mm crystals present  8  muscovite  low relief and high interference figures; fine grained and aligned, abundance decreases as distance from mica-rich bed increases  5  chlorite  high relief with low interference colours; aligned flakes  6  muscovite  high interference colours; very fine flakes aligned in the manner that could be cross bedding, at a 60/120 angle to the orientation of the bed  3  plagioclase or quartz  low relief and low interference colours; occurs in lenses, carbonate crystals are present as well (replacing the felsic lenses?)  2  black opaques  pleiochroic?  17  mica-rich bed 10%  coarser bed 5%: see description above, present in corner of slide and continues out of field of view  164  T/S # 3  Sample # %Modal Mineral Mineral Description 201.5 meta-conglomerate: heavily mica-rich with carbonate veins, matrix supported 15 veins carbonate veins 8 clast 21 globular ultramafic clast encompassing plagioclase laths 4 clast 18 cryptocrystalline felsic volcanic clast 73 matrix see description below vein mineralogy: 15%; several veins (up to 4 mm in thickness) variable relief with extremely highly interference colours; small anhedral crystals (0.08-0.1 mm), occurs in veins and 15 carbonate in patches in the slide (up to 0.8 mm in size) clast mineralogy: 8% clast 18  cryptocrystalline felsic volcanic clast; flattened oblong shape, up to 2 mm in length plagioclase or 4 quartz fine-grained plagioclase or quartz with a mosaic-like texture These clasts contains up to 10% chlorite flakes; green in PPL with high relief  clast 21  grain 3a  globular ultramafic clast encompassing plagioclase laths; flattened with tapered ends, ~1.5x0.5 mm low relief and low interference colours; fibrous, colourless 3 chlorite in PPL, white/grey in XPL, diffuse boundaries low interference colours and low relief; anhedral equant grains (up to 2 mm in size), with carbonate "tails" around 1 plagioclase the grain, sericite alteration, K-spar?  fine grained matrix: 73% 65  chlorite  low relief and low interference colours; fibrous, colourless in PPL, white/grey in XPL, diffuse boundaries  5 1  plagioclase or quartz opaques  fine-grained plagioclase or quartz, occurs in patches, usually associated with carbonate veins and patches fibrous globular shapes  2  black opaques  some euhedral blocky shapes and some anhedral flattened shapes, ~0.04 mm  165  T/S #  Sample #  4  290.4  %Modal  Mineral  Mineral Description  meta-conglomerate: heavily mica-rich with carbonate veins, matrix supported 0.5 veins carbonate vein 37 clast 15 mafic extrusive clast 20 mafic bed mafic bed with clastic texture 5 clast 19 chert 1 grains 3a, b single grains of untwinned plag and quartz 26.5 matrix see description below vein mineralogy: 0.5%; ~0.9 mm in thickness 0.4 0.1 clast mineralogy: 42% clast 21  variable relief with extremely highly interference colours; small anhedral crystals (0.04-0.1 mm)  plagioclase or quartz  low interference colours and low relief; fine grained crystals that rim the vein  extrusive clast heavily muscovite-rich, ~9x2 mm; partial clast, continued out of view off thin section and heavily metamorphosed  15  muscovite  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and flattened  7  plagioclase or quartz  low interference colours and low relief; fine grained aggregates  5 2  carbonate chlorite  4  2  clast 4  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.2 mm, occuring in single crystals green in PPL, small unaligned flakes throughout clast very black in PPL/XPL; anhedral blobs (~0.08-0.6 mm in oblong opaques length), flattened and aligned in one direction  plagioclase  low interference colours and low relief; crystals ~0.08x0.1 mm in length in anhedral shapes, single crystals or aggregates (former phenocrysts?) and flattened  anhedral to euhedral blocks of "fuzzy" masses, skeletal2 black oxide looking chert, subrounded (~2x1mm) and showing replacement  plagioclase or low relief and low interference colours; anhedral, mosaic5 quartz like texture, equant grains (from ~0.12-0.24 mm in size) These clasts contain some small laths and planks of chlorite (~3%). Carbonate crystals are present as anhedral single crystals (crystals ~0.1 mm). Also, these clasts seem to have anhedral blob-like opaques replacing them, up to 50%. low interference colours and low relief;occurs in anhedral equant grains (up to 0.1 mm in size) or fine grained infill plagioclase and between clasts and other grains; one granophyric texture grain 3a, b 1 quartz seen mafic bed: 20%, mafic bed with clastic texture, ~10 mm in thickness 9  plagioclase or quartz  4  carbonate  low interference colours and low relief; fine grained aggregates variable relief with high interference figures and distinct cleavage; anhedral up to 0.2 mm, occuring in single crystals and aggregates  166  T/S # 4  Sample #  %Modal  Mineral  Mineral Description  290.4 (continued) 2  chlorite  green in PPL, small unaligned flakes throughout clast  3  very black in PPL/XPL; anhedral blobs (~0.08-0.6 mm in oblong opaques length), flattened and aligned in one direction  1  plagioclase  low interference colours and low relief; crystals ~0.08x0.1 mm in length in anhedral shapes, single crystals or aggregates (former phenocrysts?) and flattened  1  black oxide  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking  fine grained matrix: 26.5% muscovite  low relief with high interference figures; flakes and blocks throughout slide, somewhat aligned  10  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.2 mm, occuring in single crystals and aggregates  5  plagioclase or quartz  fine-grained plagioclase or quartz, occurs in patches, usually associated with carbonate veins and patches  black opaques opaques  some euhedral blocky shapes and some anhedral flattened shapes, ~0.04 mm fibrous globular shapes  37  3 1.5  167  T/S # 5  Sample #  %Modal Mineral Mineral Description meta-conglomerate: coarse texture, matrix supported with felsic clasts and grains, 290.24 average size ~1.2x0.6 mm untwinned plagioclase, single quartz, and twinned 8 grain 3a, b, c plagioclase grains 12 clast 3 granite clast 80 matrix see description below clast mineralogy: 20% clast 3 granite clast ~4x2 mm low interference colours, polysynthetic and carlsbad twinning, biaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to sub-angular with evidence of broken crystals. Twinning is seen in some crystals and some appears bent at a shallow angle. Larger crystals can contain oligoclase and small (~0.3x0.1 mm) inclusion of a mineral. An15-25 and 2  An30. low interference colours, low relief, uniaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to subangular with evidence of broken crystals and oscillatory zoning. Larger crystals can contain small (~0.3x0.1 mm) 1 quartz inclusion of a mineral. Bent polysynthetic twinning visible in crystals. Some antiperthitic texture visible. Most plagioclase is simply twinned. Grains are poiklitic and contain up to 5% carbonate crystals. All single plagioclase and quartz crystals in this thin section is presumed to have disaggregated from the granite clasts. These are described as separate grains (below). grain 3  grain 3a  andesine  single grains of plagioclase and quartz, mostly equant and subrounded low interference colours and low relief; anhedral equant grains (~0.02-2 mm in size). Can be rounded, equant, or 7 plagioclase poiklitic or any combination of the above.  grain 3b  4  quartz  grain 3c  1  andesine  fine grained matrix: 80%  50  plagioclase or quartz  26  carbonate  2  chlorite  1  chlorite  1  opaques  low interference colours and low relief; ~2 mm in size, confirmed uniaxial, rounded polysynthetic twinning; An35, ~0.8 x 0.3 mm, equant, some carbonate crystals replacing mineral low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to0.08-0.2 mm, occuring in single crystals and aggregates (up to 1 mm thick), also as guests in felsic grains. One thin vein 0.16 mm in thickness visible. green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide black opaques, occur either anhedrally with a skeletal texture (~0.4 mm), or euhedral blocks (~0.16 mm)  168  T/S #  Sample #  6  207.16  %Modal  Mineral  Mineral Description  meta-sandstone This thin section has been heavily chloritized. The alternating felsic and mafic beds have been metamorphosed so extremely that it is difficult to distinguish between specific beds and their continuity. Below is a description of felsic and mafic beds. Some beds are folded and others are not. felsic beds: ~50% 30  plagioclase and low interference colours with low relief; fine-grained form quartz that makes up the groundmass within this bed as infill  variable relief with high interference figures and distinct 20 carbonate cleavage; anhedral up to 0.24 mm in size The carbonate is usually only associated with clast 4 (coarser-grained felsic clast) that are beginning to disaggregate, but are found as single crystals and aggregates elsewhere (but not commonly). These clasts are anhedral and display jigsaw-esque texture with carbonate present in large crystals, replacing the plagioclase/quartz. mafic beds: ~50% 44  chlorite  green in PPL, low relief; fibrous forms and small laths (of chlorite)  4  opaques  black; give a "fuzzy" texture to the bed, in addition to small anhedral shapes  plagioclase  low interference colours with low relief; some felsic minerals present within the mafic bed, small anhedral crystals  2  169  T/S #  Sample #  7  119.1  %Modal  Mineral  Mineral Description  meta-conglomerate: matrix supported single untwinned plagioclase, single quartz, twinned 10 grain 3 plagioclase grains 4  clast 19  chert  4  clast 15  mafic extrusive clast  4  clast 9  porphyritic felsic hypabyssal clast  3 2 70  clast 4 clast 3 matrix  hypabyssal felsic clast granite clast see description below  clast mineralogy: 30% grain 3  single grains of plagioclase and quartz, mostly equant and subrounded low interference colours and low relief; anhedral equant grains (up to ~0.4x0.3 mm in size). Can be rounded, equant, 5 plagioclase or poiklitic or any combination of the above. 3 2  quartz albite or andesine  low interference colours and low relief; up to 0.2x0.15 mm in size, confirmed uniaxial, rounded to subrounded polysynthetic twinning; An5 or An32, ~0.2 mm, equant  clast 19  chert, subrounded (~0.6x0.2 mm) plagioclase or low relief and low interference colours; anhedral, mosaic4 quartz like texture, equant grains (from ~0.08 mm in size) These clasts contain some small laths and planks of chlorite (~1%). Carbonate crystals are present as anhedral single crystals (crystals ~0.01 mm).  clast 15  mafic extrusive clast, ~8x2 mm plagioclase or low interference colours and low relief; fine grained 1.5 quartz aggregates 0.5 chlorite green in PPL, masses, infilling rest of texture 1  0.6 0.3 clast 9  low interference colours and low relief; crystals ~0.2 mm in length in laths and equant shapes  carbonate chlorite  variable relief with high interference figures; anhedral up to 0.2 mm, occuring in single crystals (small and rounded) and in aggregates (larger and more angular) green in PPL with high relief; small flakes  0.1 black oxide anhedral to euhedral blocks of "fuzzy" masses porphyritic felsic hypabyssal clast; ~7x4 mm in size, oblong low interference colours with low relief; fine-grained form 2 plagioclase that makes up the groundmass within this clast low interference colours with low relief; porphyroclast, ~0.8x0.5 mm in size with oscillatory extinction, simple and 0.5 plagioclase polysynthetic twinning 0.3  clast 4  plagioclase  black opaque  black dust, occurs ubiquitously throughout clast  coarse grained felsic hypabyssal clast, ~4x2 mm, few opaques, very clear in PPL low relief and low interference colours; euhedral shapes of large laths (ranging from 0.2 up to 1.0 mm) with simple and polysynthetic twinning, randomly oriented and anhedral 2 plagioclase infill between the other plagioclase green in PPL with low relief and low interference colours; 1 serpentine anhedral masses that occur in patches, thick and fibrous  170  T/S # 7  Sample #  %Modal  Mineral  Mineral Description  119.1 (continued) These clasts contain some small flakes/sprinkles of chlorite (~1%). Carbonate crystals are present as anhedral single crystals (crystals ~0.01 mm). clast 3  granite clast, small subrounded shapes ~0.8 mm in size, a few carbonate crystals as guests in the plagioclase low interference colours, polysynthetic and carlsbad  1  oligoclase and andesine  twinning, biaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to sub-angular with evidence of broken crystals. Twinning is seen in some crystals and some appears bent at a shallow angle. Larger crystals can contain small (~0.3x0.1 mm) inclusion of a mineral. An15-25 and An30.  low interference colours, low relief, uniaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to subangular with evidence of broken crystals and oscillatory zoning. Larger crystals can contain small (~0.3x0.1 mm) 0.8 quartz inclusion of a mineral. green in PPL with high relief; flakes and sprinkles 0.2 chlorite throughout, randomly oriented Bent polysynthetic twinning visible in crystals. Some perthitic/antiperthitic texture visible. Most plagioclase is simply twinned. Grains are poiklitic and contain up to 5% carbonate crystals. All single plagioclase and quartz crystals in this thin section is presumed to have disaggregated from the granite clasts. fine grained matrix: 70%  50  2  plagioclase or quartz  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size)  carbonate  variable relief with high interference figures and distinct cleavage; anhedral ~0.05 mm, occuring in single crystals also as guests in felsic grains. Thin veins 0.16 mm in thickness visible.  10 1  chlorite biotite  4 3  chlorite opaques  green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate green pleiochroic; occasional laths ~0.04 mm in length green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide black opaques, ~0.01 mm dots in slide  171  T/S # 8  Sample #  %Modal  Mineral  Mineral Description  meta-conglomerate: difficult to distinguish distinct boundaries between clasts, carbonate 332, 322.1 replacement visible, clast supported 38 clast 9 porphyritic felsic hypabyssal clast 20 clast 21 globular ultramafic clast encompassing plagioclase laths 5 clast 2 mafic effusive clast with subophitic texture 4 clast 19 chert 2 vein carbonate and plag/qtz vein 1 grain 3 untwinned plag, single quartz, and twinned plag 30 matrix see description below vein mineralogy 2%: from 0.8-1.3 mm in thickness, traverses across slide 1  plagioclase and low interference colours and low relief; up to 0.4 mm in quartz size  variable relief with high interference figures and distinct 1 carbonate cleavage; anhedral up to 0.24 mm in size clast mineralogy: 68% porphyritic felsic hypabyssal clast; very large (17+ mm) clast that continues out of field clast 9 of view low interference colours with low relief; fine-grained form 23 plagioclase that makes up the groundmass within this clast low interference colours with low relief; porphyroclast, ~0.8x0.5 mm in size with oscillatory extinction, simple and 10 plagioclase polysynthetic twinning  clast 2  5 black opaque black dust, occurs ubiquitously throughout clast This clast contains up to 4% of carbonate replacement. The carbonate occurs as replacement to the plagioclase porphyroclasts, single random crystals (up to ~0.4 mm), or as small aggregates (~0.8 mm in size). In addition, random flakes of chlorite are present as well. mafic effusive clast with subophitic texture; these plagioclase crystals are thin laths but are difficult to see 1.5 2.5 1  plagioclase plagioclase or quartz opaques  low relief, 1st O yellow colours, simple twinning visible; euhedral laths (~0.2x0.01 mm) anhedral crystals occurring between yellow plag laths (~0.1x0.1 mm) black dust, occurs ubiquitously throughout clast  This clast contains up to 4% of carbonate replacement. The carbonate occurs in random anhedral shapes (up to 0.5 mm) in clast. Also, large chlorite flakes (~0.05 mm) are visible as well throughout clast that are somewhat aligned. clast 21  clast 19  globular ultramafic clast encompassing plagioclase laths (~4x1.5 mm); flattened with diffuse boundaries with matrix very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other 15 chlorite characteristics low relief with high interference colours; small laths ~0.04x0.01 mm and flakes, up to 2% and oriented in the 5 muscovite same direction chert, subrounded (~2x0.5 mm) and showing heavy replacement plagioclase or low relief and low interference colours; anhedral, mosaic2 quartz like texture, equant grains (from ~0.12-0.24 mm in size) These clasts contain some small laths and planks of chlorite (~3%). Heavily altered by serpentine and displaying very weak boundaries.  172  T/S # 8  Sample #  %Modal  Mineral  Mineral Description  332, 322.1 (continued)  grain 3a, b  1  low interference colours and low relief; anhedral equant plagioclase and grains (~0.3 mm in size). Unable to confirm interference quartz figure.  fine grained matrix: 30%  15  plagioclase or quartz  10  carbonate  4  chlorite  1  opaques  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to0.08-0.2 mm, occuring in single crystals and aggregates (up to 1 mm thick), also as guests in felsic grains. One thin vein 0.16 mm in thickness visible. green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate black opaques, occur either anhedrally with a skeletal texture (~0.4 mm), or euhedral blocks (~0.16 mm)  173  T/S #  Sample #  10  408.75  %Modal  Mineral  metasedimentary rock: sandstone; this thin section is described in three sections below: mafic clastic bed, felsic bed, and a mafic bed with large felsic clasts 3 clast 19 chert 9 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 8 clast 23 ultramafic clast with globular epidote 50 felsic bed see description below 30 mafic bed see description below  mafic volcanic bed: ~20% clast 19 chert, large ~4 mm plagioclase or 3 quartz  clast 16  Mineral Description  low interference colours with low relief; interlocking texture with crystals ~0.04 mm in size  These clasts contain some small ~0.08 mm in length sprinkles of muscovite. There are also high relief minerals chlorite?) present. Due to its fine grained nature, this clast possibly is chert. aphanitic mafic volcanic clast with aggregates of oxides, ~5x1 mm, up to ~17 mm 6  muscovite  fine grained muscovite flakes, somewhat aligned  3 black oxide small oxide spots, black powder ubiquitous These clasts are rounded and flattened. The proportions of muscovite varies for the clasts, ranging from 5-7%. clast 23 ultramafic clast with globular epidote (~17x5 mm), up to 5% black oxides and some carbonate crystals present very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other 8 chlorite characteristics bedding infill: ~2% serpentine or green in PPL, low relief; fibrous forms and small laths (of 1 chlorite chlorite) are present 0.3  plagioclase and low interference colours and low relief; fine grained, rare quartz occurrenc  0.3  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.24 mm in size  0.4  black oxide  small oxide spots, black powder ubiquitous  40  plagioclase and low interference colours with low relief; fine-grained form quartz in fibrous or indistinct shapes  felsic bed: 50%  variable relief with high interference figures and distinct 8 carbonate cleavage; anhedral up to 0.24 mm in size 2 black opaque black dust, occurs ubiquitously throughout clast This bed contains up to 4% of carbonate replacement. The carbonate occurs as single random crystals (up to ~0.4 mm), or as small aggregates (~0.8 mm in size). In addition, random flakes of chlorite are present as well. Carbonate veins (up to 1 mm thick) are seen in bed. mafic bed with large felsic clasts: 30% rounded quartz clast ~2 mm, rounded and partially replaced by carbonate 1  quartz  low interference colours, low relief, uniaxial;  This clast is broken and looks as if being cut by bedding.  174  T/S # 10  Sample #  %Modal  Mineral  Mineral Description  408.75 (continued) bedding infill: ~20% 9  serpentine or chlorite  green in PPL, low relief; fibrous forms and small laths (of chlorite) are present  7  muscovite  fine grained muscovite flakes, somewhat aligned  2  black oxide  small oxide spots, black powder ubiquitous  1  plagioclase and low interference colours and low relief; fine grained, rare quartz occurrenc  1  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.24 mm in size  175  T/S #  Sample #  11  285.45  %Modal Mineral Mineral Description meta-conglomerate: this slide is divided into two clasts separated by a small rim and each of these are described below 30 clast 11 porphyritic felsic volcanic clast porphyritic clast with plagioclase displaying perthitic 70 clast 10 texture  porphyritic felsic volcanic clast (clast 11): 30% low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 10 quartz (~0.05 mm in size)  9  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?)  low interference colours and low relief; anhedral equant grains (0.4~2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple twinning visible. Strange perthitic/antiperthitic texture 5 plagioclase visible on some. green in PPL with high relief; flakes and sprinklees 2 chlorite randomly oriented occurring throughout slide low interference colours and low relief; up to 2x2 mm in size, confirmed uniaxial, rounded to subrounded, oscillatory 2 quartz extinction This clast is coated in a mafic rim of aligned chlorite/serpentine with carbonate aggregates present (up to 20%). This clast is fully enclosed within this boundary, while the other clast (described below) has begun to disaggregate at the rim. porphyritic clast with plagioclase displaying perthitic texture (clast 10): 70% This clast has begun to disaggregate at the rim, evidenced by smaller clasts that have fallen off the main body and the heavily carbonate alteration present at the transition between this clast and the other. low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 30 quartz (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly 19 carbonate replacing clasts?) variable relief with high interference figures and distinct cleavage; subhedral to euhedral single rhombs (~0.04-0.08 14 carbonate mm in size) These carbonate crystals are presumed to have completely replaced the former microphenocrysts. Due to the euhedral shape of most, I suspect plagioclase has been replaced. low relief with low interference colours; ~2x1 mm in size, 1 plagioclase aggregate of plag/qtz, possibly former large phenocrysts These former phenocrysts retain a euhedral shape, suggesting possible recrystallization. Also, black blob-like opaques (magnetite?) are restricted to the insides of these porphyroclasts. Carbonate crystals are present as well. green in PPL with high relief; flakes and sprinklees 5 chlorite randomly oriented occurring throughout slide 1 opaques black dust, occurs ubiquitously throughout clast  176  T/S #  Sample #  12  257.8  %Modal Mineral Mineral Description meta-conglomerate: clast supported with clasts elongate and flattened, average sized 9 mm in length 20 clast 11 porphyritic felsic volcanic clast 20 clast 17 aphanitic extrusive felsic clast 19 clast 20 carbonate-rich chert  5 2 7 30 clast mineralogy: 70% clast 11  porphyritic clast withplagioclase displaying perthitic texture single plagioclase and quartz grains chert see description below  porphyritic felsic volcanic clast: small and rounded, ~2 mm  3  plagioclase or quartz  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size)  variable relief with high interference figures and distinct cleavage; anhedral up to 0.04 mm in size low interference colours and low relief; anhedral equant grains (0.4~2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple 6 plagioclase twinning visible. green in PPL with high relief; flakes and sprinklees 1 chlorite randomly oriented occurring throughout slide aphanitic extrusive felsic clast, ~8x3 mm plagioclase or low interference colours and low relief; fine grained plag or 10 quartz qtz that makes up the groundmass of this clast low relief and distinctive interference colours; up to ~0.02 7 muscovite mm in size, occurs in single crystals black opaques, occur either anhedrally with a skeletal 3 opaques texture (~0.4 mm), or euhedral blocks (~0.16 mm) 10  clast 17  clast 10 grain 3 clast 19 matrix  carbonate  clast 20  carbonate-rich chert, ~4x2 mm variable relief and distinctive interference colours; up to ~0.2 mm in size, occurs in single crystals and patches up to 15 carbonate 1 mm in size plagioclase or low interference colours and low relief; fine grained plag or 4 quartz qtz that makes up the groundmass of this clast  clast 10  porphyritic clast with perthitic texture: extremely flattened low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 3 quartz (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly 2 carbonate replacing clasts?) variable relief with high interference figures and distinct cleavage; subhedral to euhedral single rhombs (~0.04-0.08 1 carbonate mm in size)  grains 3  These carbonate crystals are presumed to have completely replaced the former microphenocrysts. Due to the euhedral shape of most, I suspect plagioclase has been replaced. They are extremely flattened.  177  T/S # 12  Sample #  %Modal  Mineral  Mineral Description  257.8 (continued) clast 19  chert (~2x1 mm), rounded plagioclase or 5 quartz  2  carbonate  low relief and low interference colours; indistinct boundaries between crystals variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals  Chlorite sprinkles are present up to 1%, randomly oriented. fine grained matrix: 30% plagioclase or quartz carbonate  serpentine chlorite opaques  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to0.08-0.2 mm green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide black opaques, occur either anhedrally with a skeletal texture (~0.4 mm), or euhedral blocks (~0.16 mm)  178  T/S #  Sample #  13  424.7  %Modal  Mineral  Mineral Description  meta-conglomerate: clast supported with large rounded clasts, ~18 mm 25 clast 12 felsic volcaniclastic clast 20 clast 13 porphyritic granitoid clast 15 clast 17 aphanitic extrusive felsic clast 9 clast 20 carbonate-rich chert 6 clast 2 mafic effusive clast with subophitic texture 6 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 4 clast 19 chert 15 matrix see description below clast mineralogy: 85% clast 12  felsic volcaniclastic clast  low relief and low interference colours; form porphyroblasts ~0.4 mm in size, rounded, occurs in single crystals and aggregates, simple and polysynthetic twinning seen  10  plagioclase or quartz plagioclase or quartz  2  carbonate  low relief and low interference colours; infilling as matrix variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals and aggregates  1  opaques  black dust, occurs ubiquitously throughout clast, forms euhedral shapes  12  The black opaques are retaining remmant euhedral shapes, possibly replacing biotite. clast 13  porphyritic granitoid clast  9  plagioclase or quartz plagioclase or quartz  2 1  carbonate opaques  8  low relief and low interference colours; form porphyroblasts ~0.4 mm in size, rounded, occurs in single crystals and aggregates, simple and polysynthetic twinning seen low relief and low interference colours; infilling as matrix variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals and aggregates black dust  This clast is similar to clast 12, except for the absence of euhedral opaques clast 17  aphanitic extrusive felsic clast, ~8x3 mm plagioclase or low interference colours and low relief; fine grained plag or 9 quartz qtz that makes up the groundmass of this clast low relief and distinctive interference colours; up to ~0.02 6 muscovite mm in size, occurs in single crystals  clast 20  carbonate-rich chert, ~3x1.5 mm, elongate, crosscut by vein plagioclase or low interference colours and low relief; fine grained plag or 7 quartz qtz that makes up the groundmass of this clast variable relief and distinctive interference colours; up to 2 carbonate ~0.1 mm in size, occurs in single crystals and patches  clast 2  mafic effusive clast with subophitic texture, ~1x1.5 mm and rounded low relief, 1st O yellow colours, simple twinning visible; 2 plagioclase euhedral laths (up to 0.4 mm in length) 3  plagioclase or quartz  anhedral crystals occurring between yellow plag laths (~0.1x0.1 mm)  179  T/S # Sample # %Modal 13 424.7 (continued)  clast 16  Mineral  Mineral Description  1 opaques black dust, occurs ubiquitously throughout clast aphanitic mafic volcanic clast with aggregates of oxides, ~4x2 mm in size; soft deformation seen 2-4 3  muscovite black oxide  fine grained muscovite flakes, somewhat aligned small oxide spots, black powder ubiquitous  Chlorite is present (~1%) in flakes, with some globular epidote (?). clast 19  chert, oval shaped, ~3x2 mm plagioclase or low interference colours with low relief; interlocking 5 quartz texture with crystals ~0.04 mm in size These clasts contain some small ~0.08 mm in length sprinkles of chlorite.  fine grained matrix: 15%  8  chlorite  3  plagioclase or quartz  2  biotite?  2  opaques  green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) pleiochroic brown and green in PPL; occasional small aggregates of biotite laths ~0.8 mm in size at random orientations black opaques, occur either anhedrally with a skeletal texture (~0.4 mm), or euhedral blocks (~0.16 mm)  180  T/S #  Sample #  14  222.63  clast 5  %Modal  Mineral  Mineral Description  meta-conglomerate: clast 5 makes up the majority of the thin section (~95%) and displays a mafic rim around it while sharing a boundary with a clast 10 95 clast 5 vesicular clast with mafic enclaves porphyritic clast with plagioclase displaying perthitic 5 clast 10 texture vesicular clast with mafic enclaves plagioclase and low interference colours and low relief; fine grained and 74 quartz infilling between phenocrysts low interference colours and low relief; euhedral laths (~0.40.8 mm in length) as phenocrysts. simple and polysynthetic 20 plagioclase twinning visible variable relief with high interference figures and distinct 15 carbonate cleavage; anhedral up to 0.04 mm in size  8  5  Occurs as random anhedral crystals and in veins up to 0.4 mm in thickness opaques black opaque powder throughout clast low relief with low interference colours; replaced plagioclase or phenocrysts? occur as aggregates (0.4-0.8 mm in size) of quartz small (~0.04 mm in size) crystals.  The shapes of these aggregates indicate these are infilled vesicles. Towards the center of these aggregates, the plagioclase/quartz crystals increase in size. Some carbonate present (up to 2%). chlorite 8 enclaves green in PPL, fibrous; enclave consists mostly of chlorite The enclaves consist of fibrous chlorite and poikilitic plagioclase phenocrysts (?). The plagioclase (0.2-0.8 mm in size) are subrounded to anhedral, unevenly distributed within the enclave, some even jutting outside the confines of the chlorite boundary. The enclave boundary is curvilinear and scalloped. Possible magma mixing? Opaques are concentrated around this enclave. clast 10  porphyritic clast with plagioclase displaying perthitic texture low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 2.5 quartz (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly 1.5 carbonate replacing clasts?) These carbonate crystals are presumed to have completely replaced the former microphenocrysts. Due to the euhedral shape of most, I suspect plagioclase has been replaced. low relief with low interference colours; ~2x1 mm in size, 1 plagioclase aggregate of plag/qtz, possibly former large phenocrysts These former phenocrysts retain a euhedral shape, suggesting possible recrystallization. Also, black blob-like opaques (magnetite?) are restricted to the insides of these porphyroclasts. Carbonate replacement is up to 80%  181  T/S # 15  Sample #  %Modal  Mineral  Mineral Description  meta-conglomerate: clast supported with large rounded clasts, most of the slide consists of a large clast that continues out of the field of view 6 clast 20 carbonate-rich chert 9 clast 19 chert 2 clast 2 mafic effusive clast with subophitic texture 2 clast 24 micro-porphyritic ultramafic clast 1 grain 3 single plagioclase and quartz grains 75 matrix see description below clast mineralogy: 85% 382  clast 20  carbonate-rich chert, ~3x1.5 mm, elongate plagioclase or low interference colours and low relief; fine grained plag or 3 quartz qtz that makes up the groundmass of this clast variable relief and distinctive interference colours; up to 2 carbonate ~0.1 mm in size, occurs in single crystals and patches  clast 19  chert, subrounded (~2x1 mm) plagioclase or low relief and low interference colours; anhedral, mosaic9 quartz like texture, equant grains (from ~0.08 mm in size) These clasts contain some small laths and planks of chlorite (~1%).  clast 2  mafic effusive clast with subophitic texture, ~3x2 mm and rounded 1 0.55 0.05  clast 24  plagioclase  low relief, 1st O yellow colours, simple twinning visible; euhedral laths (up to 0.4 mm in length)  plagioclase or quartz opaques  anhedral crystals occurring between yellow plag laths (~0.1x0.1 mm) black dust, occurs ubiquitously throughout clast  micro-porphyritic ultramafic clast, ~7 mm in size, rounded 1 0.8  chlorite  low relief and green in PPL; fibrous  muscovite  low relief, high interference colours; rounded ~0.01 mm aggregates  very high relief with very high interference colours; ~0.01 0.2 rutilte mm small acicular form Some chloritized clasts are stretched and almost disaggregates; laths of pleiochroic green/brown biotite is present as well. grains 3a, 3b  1  plagioclase or quartz  low interference colours and low relief; anhedral equant grains (~0.06 mm in size), untwinned  50  plagioclase or quartz  8  carbonate  5  serpentine  6  plagioclase or quartz  3  chlorite  low relief and low interference colours; makes up rounded aggregates (~1.5 mm), clasts and fine-grained groundmass variable relief with high interference figures and distinct cleavage; anhedral and occurs in "fuzzy" aggregates and single crystals green in PPL, fibrous form; occurs in anhedral masses up to 0.4 mm in size and randomly in slide, some are somewhat rounded, other are flattened and elongate low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide  matrix  182  T/S # 15  Sample #  %Modal  Mineral  Mineral Description  382 (continued) 2  opaques  1  biotite?  black dust, occurs ubiquitously throughout clast pleiochroic brown and green in PPL; occasional small aggregates of biotite laths ~0.8 mm in size at random orientations  183  T/S #  Sample #  16  222.15  clast 3  %Modal Mineral Mineral Description meta-conglomerate: this slide is a view of a contact between to large (17+ mm) clasts; they continue out of the field of view, A fibrous chlorite boundary separates these clasts and the felsic clast is possibly is beginning to disaggregate at its contact with the mafic clast, displayed by the texture. More flakes of muscovite are concentrated around this area, too. rounded granite clast, 17+ mm in size and continues out of field of view; makes up ~80% of slide low interference colours, polysynthetic and carlsbad twinning, biaxial; ~4x1 mm, some poikilitic with alteration texture. Twinning is seen in some crystals and some appears 45 oligoclase bent at a shallow angle. An11-24. low interference colours, low relief, uniaxial; ~4x1 mm, 20 quartz oscillatory zoning variable relief and distinctive interference colours; occuring in patches of aggregates and thin veins (~0.1 mm in 7 carbonate thickness) are present black "striped" alteration feature, possibly an alteration of 3 opaque biotite?, may be fibrous serpentine Bent polysynthetic twinning visible in crystals. Some perthitic and antiperthitic textures visible, distinguished by the alteration of K-spar. Flakes of chlorite present as well throughout clase.  fine grained matrix: 25%  2  muscovite  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and flattened  5  plagioclase or quartz  low interference colours and low relief; fine grained aggregates  4  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.2 mm, occuring in single crystals  9  chlorite  green in PPL, small unaligned flakes throughout clast  5  black oxide  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking, also occurs as tendrils  184  T/S #  Sample #  %Modal  17  258.79  meta-conglomerate: large clasts that continue out of field of view  clast 11  porphyritic felsic volcanic clast low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 10 quartz (~0.05 mm in size)  4  Mineral  carbonate  3  plagioclase  2  chlorite  1  quartz  Mineral Description  variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?) low interference colours and low relief; anhedral equant phenocrysts (~3x2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple twinning visible. Strange perthitic/antiperthitic texture visible on some. green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide low interference colours and low relief; up to 2x2 mm in size, confirmed uniaxial, rounded to subrounded, oscillatory extinction  This clast is very large and continues out of field of view. A 2x2 mm hexagonal isotropic mineral is present as well, possibly a perfect quartz crystal with its c-axis perfectly oriented. inequigranular matrix: 80%  35  plagioclase or quartz  25  plagioclase  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) low interference colours and low relief; occurs in anhedral equant clasts (~2x1 mm in size) (subrounded, subangular or poikilitic with diffuse boundaries) or aggregates (~4 mm in length) with very small crystals (~0.08 mm)  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?)  10  5  muscovite  5  chlorite  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide  185  T/S #  Sample #  18  310.6  %Modal  Mineral  Mineral Description  meta-conglomerate: large clasts that continue out of field of view 85 12 2 1 1 1  clast or matrix clast 11 clast 17 clast 1 clast 19 clast 23  see description clast porphyritic felsic volcanic clast aphanitic extrusive felsic clast mafic hypabyssal clast with subophitic texture chert ultramafic clast with globular epidote  clast or matrix 60  plagioclase or quartz  18  carbonate  5  chlorite  2  opaques  low interference colours and low relief; indistinct crystals that make up most of this clast variable relief with high interference figures and distinct cleavage; anhedral up to 0.04 mm in size occuring in single crystals or elongate flattened patches (~2 mm in length) very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other characteristics small (~0.1 mm) euhedral opaques, mostly associated with the patches with serpentine  This area is possibly clastic matrix or a heterogeneous clast. There are quite a few angular "clasts" of felsic material. On the other hand, there are no distinct boundaries between other clasts and this feature. clast 11  porphyritic felsic volcanic clast: small and rounded, ~2 mm low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 8 quartz (~0.05 mm in size) 1  carbonate  2  plagioclase  1  chlorite  variable relief with high interference figures and distinct cleavage; anhedral up to 0.04 mm in size low interference colours and low relief; anhedral equant grains (0.4~2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple twinning visible. green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide  clast 17  aphanitic extrusive felsic clast, ~8x3 mm plagioclase or low interference colours and low relief; fine grained plag or quartz qtz that makes up the groundmass of this clast low relief and distinctive interference colours; up to ~0.02 muscovite mm in size, occurs in single crystals  clast 1  mafic hypabyssal clast with subophitic texture: (~2x2 mm), rounded low relief, 1st O yellow colours, simple twinning visible; 0.4 plagioclase euhedral laths with indistinct crystal boundaries plagioclase or anhedral crystals occurring between yellow plag laths 0.5 quartz (~0.1x0.1 mm) 0.1 opaques black dust, occurs ubiquitously throughout clast  clast 19  chert: (~2x1 mm), elongate and flattened plagioclase or low relief and low interference colours; anhedral, mosaicquartz like texture, equant grains (from ~0.12-0.24 mm in size)  186  T/S # 18  Sample #  %Modal  Mineral  Mineral Description  310.6 (continued) Rounded ~2 mm in size with mostly plagioclase or quartz making up the clast. The minerals are irregular crystal shapes and not very well defined. Chlorite sprinkles are present up to 1%, randomly oriented. clast 23  ultramafic clast with globular epidote (~1x0.75 mm) replaced mafic clast very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other 1.7 chlorite characteristics high relief with high interference colours; "bubbly" aggregate form as well as elongate crystals (~0.05 mm in 0.3 epidote? length)  187  T/S #  Sample #  %Modal  19  291.23  meta-conglomerate: inequigranular clasts porphyritic clast with plagioclase displaying perthitic 86 clast 10 texture 11 clast 17 aphanitic extrusive felsic clast 1 clast 19 chert 10 matrix see description below  clast 10  porphyritic clast with plagioclase displaying perthitic texture low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 45 quartz (~0.05 mm in size)  20  20  Mineral  Mineral Description  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?)  carbonate  variable relief with high interference figures and distinct cleavage; subhedral to euhedral single rhombs (~0.04-0.08 mm in size)  These carbonate crystals are presumed to have completely replaced the former microphenocrysts. Due to the euhedral shape of most, I suspect plagioclase has been replaced. They are extremely flattened.  clast 17  clast 19  low relief with low interference colours; ~2x1 mm in size, 1 plagioclase aggregate of plag/qtz, possibly former large phenocrysts aphanitic extrusive felsic clast: ~4x3 mm, many clasts within close promixity of each other, displaying soft deformation (?) low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and 4 muscovite flattened plagioclase or low interference colours and low relief; fine grained 3 quartz aggregates 2 chlorite green in PPL, small unaligned flakes throughout clast very black in PPL/XPL; anhedral blobs (~0.08-0.6 mm in 1 oblong opaques length), flattened and aligned in one direction anhedral to euhedral blocks of "fuzzy" masses, skeletal1 black oxide looking chert (~2x2 mm), anhedral plagioclase or low relief and low interference colours; anhedral, mosaic1 quartz like texture, equant grains (from ~0.12-0.24 mm in size) Rounded ~2 mm in size with mostly plagioclase or quartz making up the clast. The minerals are irregular crystal shapes and not very well defined. Muscovite and chlorite sprinkles are present up to 1%, randomly oriented.  inequigranular matrix: 10%  5  plagioclase or quartz  4  chlorite  1  carbonate  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size) slightly green pleiochroic with low 2st order interference colours; fibrous forms in small aggregates (~0.8 mm) variable relief w/ high interference figures, distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?)  188  T/S #  Sample #  20  263.5  %Modal  Mineral  Mineral Description  meta-andesite: porphyritic, hypidiomorphic This slide displays a very dark homogenous igneous rock with replaced phenocrysts (now chlorite and biotite). There are microphenocrysts with borders difficult to distinguish, but there are 2 very large (~4 mm in length) euhedral replaced phenocrysts. No foliation present.  slide mineralogy low relief, green in PPL, anomalous blue/grey colours in 30 chlorite XPL; small fibrous patches In addition to chlorite dispersed in the groundmass, two large phenocrysts have been replaced by fibrous chlorite in ~4x2 mm euhedral shapes. Judging by the euhdral shape, I suspect plagioclase phenocrysts have been replaced. 30  biotite  medium relief, brown pleiochroic in PPL; ranges from fibrous to small laths, dispersed throughout slide  In addition to being evenly dispersed in the slide, the biotite is also replacing microphenocrysts, more along the edges with chlorite being in more in the center. variable relief with high interference figures and distinct cleavage; anhedral up to 0.5 mm in size or in massive 35 carbonate textures in most of the slide plagioclase or low interference colours and low relief; occasional anhedral 2.5 quartz equant grains (~0.1 mm in size) small euhedral black opaques ~0.04 mm in size, slight dark 1 sphene birefringence small anhedral clusters of black opaques with "fuzzy" 1 pyrite texture high relief with 2nd order red and blue interference colours; small (0.1 mm in length) euhedral laths occuring within the 0.5 epidote microphenocrysts  189  T/S #  Sample #  21  385.56  clast 17  clast 20  clast 13  %Modal  Mineral  meta-conglomerate: inequigranular clasts 59 clast 17 aphanitic extrusive felsic clast 10 clast 20 carbonate rich chert 10 clast 13 porphyritic granitoid clast 10 clast 14 porphyritic rhyolite 5 clast 12 felsic volcaniclastic clast 1 clast 24 micro-porphyritic ultramafic clast aphanitic extrusive felsic clast, ~4x3 mm, many clasts within close promixity of each other, displaying soft deformation (?) low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and 29 muscovite flattened 18  plagioclase or quartz  low interference colours and low relief; fine grained aggregates  5  chlorite  green in PPL, small unaligned flakes throughout clast  4  very black in PPL/XPL; anhedral blobs (~0.08-0.6 mm in oblong opaques length), flattened and aligned in one direction  3  black oxide  low relief and high birefringence; fibrous masses that make up most of the clast  mica plagioclase or 4 quartz low relief and low interference colours; infilling as matrix It is difficult to determine if this clast is felsic porphyroblasts with a groundmass that has been replaced by mica or if this clast was wholly felsic and mica has been alteration. black dust, occurs ubiquitously throughout clast, some form 1.5 opaques euhedral shapes slightly green pleiochroic with low 2st order interference 0.5 serpentine colours; fibrous forms in small aggregates (~0.8 mm) porphyritic rhyolite, large 17+ mm in size 6.3  plagioclase or quartz  low relief and low interference colours; infilling as matrix  1  plagioclase or quartz  low relief and low interference colours; rounded phenocrysts ~0.8 mm in size  mica  low relief and high birefringence; fibrous masses variable relief and distinctive interference colours; forming masses, secondary alteration  1.5 1 clast 12  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking  carbonate rich chert, ~17+ cm and continues out of field of view plagioclase or low interference colours and low relief; fine grained plag or 8 quartz qtz that makes up the groundmass of this clast variable relief and distinctive interference colours; up to 2 carbonate ~0.2 mm in size porphyritic granitoid clast, ~18x10 mm in size 4  clast 14  Mineral Description  carbonate  felsic volcaniclastic clast  2.5  plagioclase or quartz  low relief and low interference colours; form porphyroblasts ~0.4 mm in size, rounded, occurs in single crystals and aggregates, simple and polysynthetic twinning  190  T/S # 21  Sample # %Modal 385.56 (continued)  clast 24  Mineral  Mineral Description  0.5  plagioclase or quartz  1.5  carbonate  low relief and low interference colours; infilling as matrix variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals and aggregates  0.5  opaques  black dust, occurs ubiquitously throughout clast, some form euhedral shapes  micro-porphyritic ultramafic clast, ~3.5 mm in size, rounded 0.5  chlorite  low relief and green in PPL; fibrous  0.5  muscovite  low relief, high interference colours; rounded ~0.01 mm aggregates  Some chloritized clasts are stretched and almost disaggregates; laths of pleiochroic green/brown biotite is present as well.  191  T/S # 22  Sample #  %Modal Mineral Mineral Description meta-conglomerate: inequigranular clasts with flattened and elongated shapes, tapered 286.44 points is common, thick felsic vein (0.8 mm in thickness) crosscuts one corner porphyritic clast with plagioclase displaying perthitic 29 clast 10 texture 29 clast 17 aphanitic extrusive felsic clast 1 clast 19 chert 1 vein see description below 40 matrix see description below vein mineralogy (1%): 0.8 mm in thickness plagioclase or 0.5 quartz finer grained (crystals ~0.08 mm in size), mosaic texture  clast 10  variable relief and distinctive interference colours; anhedral 0.5 carbonate crystals within the vein porphyritic clast with plagioclase displaying perthitic texture low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 15 quartz (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly 11 carbonate replacing clasts?) variable relief with high interference figures and distinct 3 carbonate cleavage; subhedral aggregates (~0.04-0.08 mm in size) These carbonate crystals are presumed to have completely replaced the former microphenocrysts. Due to the euhedral shape of most, I suspect plagioclase has been replaced. They are extremely flattened. 1  clast 17  plagioclase  low relief with low interference colours; ~2x1 mm in size, aggregate of plag/qtz, possibly former large phenocrysts  aphanitic extrusive felsic clast: ~4x3 mm, many clasts within close promixity of each other, displaying soft deformation (?) low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and 10 muscovite flattened 10 5  plagioclase or quartz chlorite  low interference colours and low relief; fine grained aggregates green in PPL, small unaligned flakes throughout clast  4  black oxide  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking  clast 19  chert, large ~8 mm plagioclase or 5 quartz inequigranular matrix: 40% 25  serpentine  10  plagioclase or quartz  5  carbonate  low interference colours with low relief; interlocking texture with crystals ~0.04 mm in size slightly green pleiochroic with low 2st order interference colours; fibrous forms in small aggregates (~0.8 mm) low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 in size) variablemm relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, single and aggregates patches up to 4x1 mm (possibly replacing clasts?)  192  T/S # 23  Sample # 385.6  %Modal  Mineral  Mineral Description  meta-conglomerate: inequigranular clasts with flattened and elongated shapes, sizes range from ~9-17 mm in length 45 clast 17 aphanitic extrusive felsic clast 15 clast 11 porphyritic felsic volcanic clast 10 clast 14 porphyritic rhyolite 5 clast 4 hypabyssal felsic clast 4 clast 12 felsic volcaniclastic clast 3 clast 23 ultramafic clast with globular epidote 1 clast 6 porphyritic mafic clast 1 clast 2 mafic effusive clast with subophitic texture 1 vein see description below 15 matrix see description below  vein mineralogy (1%): 0.4 mm in thickness plagioclase or 0.5 quartz finer grained (crystals ~0.08 mm in size), mosaic texture 0.5 clast 17  variable relief and distinctive interference colours; anhedral crystals within the vein  aphanitic extrusive felsic clast, ~5-9 mm in size; these clasts are clustered together and display soft deformation boundaries between them  15  muscovite  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and flattened  12  plagioclase or quartz  low interference colours and low relief; fine grained aggregates  7 3  carbonate chlorite  4  clast 11  carbonate  variable relief with high interference figures and distinct cleavage; anhedral up to 0.2 mm, occuring in single crystals green in PPL, small unaligned flakes throughout clast very black in PPL/XPL; anhedral blobs (~0.08-0.6 mm in oblong opaques length), flattened and aligned in one direction  2  plagioclase  low interference colours and low relief; crystals ~0.08x0.1 mm in length in anhedral shapes, single crystals or aggregates (former phenocrysts?) and flattened  2  black oxide  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking  porphyritic felsic volcanic clast: small and rounded, ~8 mm low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 7 quartz (~0.05 mm in size) variable relief with high interference figures and distinct 5 carbonate cleavage; anhedral up to 0.04 mm in size low interference colours and low relief; anhedral equant grains (0.4~2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple 2 plagioclase twinning visible. green in PPL with high relief; flakes and sprinklees 1 chlorite randomly oriented occurring throughout slide  193  T/S # 23  Sample #  %Modal  Mineral  Mineral Description  385.6 (continued) clast 14 porphyritic rhyolite: small and elongate ~8 mm in length 6.5  plagioclase or quartz  low relief and low interference colours; infilling as matrix  1  plagioclase or quartz  low relief and low interference colours; rounded phenocrysts ~0.8 mm in size  mica  low relief and high birefringence; fibrous masses variable relief and distinctive interference colours; forming masses, secondary alteration  1.5 1 clast 4  clast 12  carbonate  hypabyssal felsic clast, ~3x1 mm  2.5  plagioclase  low relief and low interference colours; euhedral shapes of large laths (ranging from 0.2 up to 1.0 mm) with simple and polysynthetic twinning, randomly oriented and anhedral infill between the other plagioclase  2 0.5  carbonate opaques  variable relief and distinctive interference colours; anhedral crystals within the vein black dust, occurs ubiquitously throughout clast  felsic volcaniclastic clast  3 1  0.5 0.5  plagioclase or quartz plagioclase or quartz  low relief and low interference colours; form porphyroblasts ~0.4 mm in size, rounded, occurs in single crystals and aggregates, simple and polysynthetic twinning seen  carbonate  low relief and low interference colours; infilling as matrix variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals and aggregates  opaques  black dust, occurs ubiquitously throughout clast, forms euhedral shapes  The black opaques are retaining remmant euhedral shapes, possibly replacing biotite. clast 23  clast 6  clast 2  23  ultramafic clast with globular epidote: (~1x0.75 mm) very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other 0.8 chlorite characteristics completely black and elongate in the same direction (~0.2 0.2 opaques mm in length) porphyritic mafic clast (~2x1 mm): Displays original phenocrystic texture, but all replaced; thus being porphyroblastic plagioclase eu-subhedral tabular crystals (~0.25-0.2 mm) with muscovite and chlorite flakes (up to 50% of the 0.7 porphyroblasts porphyroblast) fine-grained plagioclase or quartz; low interference colours with low 0.2 matrix relief with fine grained texture 0.1 oxides black oxide powder, evenly distributed across clast mafic effusive clast with subophitic texture low relief, 1st O yellow colours, simple twinning visible; 1.5 plagioclase euhedral laths (~0.2x0.01 mm)  385.6 (continued)  194  T/S #  Sample #  %Modal 0.5 0.5  Mineral plagioclase or quartz opaques  Mineral Description anhedral crystals occurring between yellow plag laths (~0.1x0.1 mm) black dust, occurs ubiquitously throughout clast  inequigranular matrix: 15%  7  carbonate  5  plagioclase or quartz  variable relief with high interference figures and distinct cleavage; anhedral up to 0.08-0.2 mm, occur in single crystals or in aggregate patches up to 4x1 mm (possibly replacing clasts?) low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size)  3  serpentine  slightly green pleiochroic with low 2st order interference colours; fibrous forms in small aggregates (~0.8 mm)  195  T/S #  Sample #  24  281.33  %Modal  Mineral  Mineral Description  Contact between two clasts of different mineralogy, one more felsic than the other. The felsic section takes up most of the slide and is referred to as the "light side" and the more mafic section which takes up only a portion of a corner is referred to as the "dark side"  light side mineralogy: 80% This rock is a metamorphosed former plutonic rock. The 'patches' described below are replaced single grains. medium relief, straight extinction, 3rd O interference colours yellow orange and blue; occurs in masses of small 35 muscovite laths (range from 0.02-0.09 mm) variable relief with high interference colours; occurs in anhedral masses of anhedral crystals, associated with the 20 carbonate serpentine and some opaques  8  chlorite  green in XPL, low relief, fibrous; occurs in fibrous anhedral masses, very dark in XPL, associated with carbonate  The carbonate and chlorite form irregular patches ~8 mm in length throughout the slide. This is interpreted as replacement of former grains within the plutonic rock. Because of the irregular shapes, it is difficult to distinguish what the original mineral was, but due to the presence of talc and chlorite, I suspect this rock was intermediate in composition.  5  plagioclase or quartz  low interference colours with low relief; small (~0.03 mm) aggregates in irregular lenticular shapes, associated with the carbonate  2  opaques  black an-to euhedral shapes, up to 0.4 mm in size, usually associated with carbonate masses  dark side mineralogy: 20% This dark side is darker in PPL, with irregular carbonate shapes distributed throughout that are larger and therefore stand out. medium relief, straight extinction, 3rd O interference colours yellow orange and blue; occurs in masses of small 8 muscovite laths (range from 0.02-0.09 mm)  5  3  2 1  carbonate  variable relief with high interference colours; occurs more commonly as single euhedral crystals (~0.2 mm) or less commonly in anhedral masses  plagioclase or quartz  low interference colours with low relief; small (~0.03 mm) aggregates in irregular lenticular shapes up to 2mm in length  chlorite  green in XPL, low relief, fibrous; one 2 mm rounded aggregate is seen, but other occurences of this is very uncommon  opaques  black anhedral opaques, occurs in large (0.4 mm) anhedral grains or powder  196  T/S # 25  Sample # 34.4  %Modal  Mineral Description  meta-conglomerate: clast supported with large clasts (~2-8 mm in size), elongate or rounded shapes 35 clast 19 chert 25 15  clast 19  Mineral  grains 3 clast 17  single grains of untwinned plagioclase, quartz, and twinned plagioclase grains aphanitic extrusive felsic clast  13 clast 14 porphyritic rhyolite 12 clast 11 porphyritic felsic volcanic clast 15 matrix see description below chert, large (~0.5-4 mm) and completely anhedral plagioclase or low interference colours with low relief; interlocking 40 quartz texture with crystals ~0.04 mm in size  These clasts contain some small ~0.08 mm in length sprinkles of muscovite. There are also high relief minerals (mafic minerals?) present. Due to its fine grained nature, this clast possibly is chert. low interference colours and low relief; anhedral equant grains (~4 mm in size). untwinned and/or poikilitic, jigsaw grains 3a 14 plagioclase texture, some perthitic texture seen low interference colours and low relief; anhedral equant grain 3b 10 quartz grains (~4 mm in size), displaying oscillatory extinction grain 3c clast 17  1  clast 11  plagioclase or quartz chlorite  low interference colours and low relief; fine grained aggregates green in PPL, small unaligned flakes throughout clast  2  muscovite  2  plagioclase  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and flattened low interference colours and low relief; crystals ~0.08x0.1 mm in length in anhedral shapes, single crystals or aggregates (former phenocrysts?) and flattened  anhedral to euhedral blocks of "fuzzy" masses, skeletal2 black oxide looking porphyritic rhyolite, ~9x2 mm plagioclase or 7 quartz low relief and low interference colours; infilling as matrix 3  plagioclase or quartz  low relief and low interference colours; rounded phenocrysts ~0.8 mm in size  2  mica  1  carbonate  low relief and high birefringence; fibrous masses variable relief and distinctive interference colours; forming masses, secondary alteration  porphyritic felsic volcanic clast, ~2 mm  5 25  albite twinning and only 1 grain found; single subhedral grain (~0.4 mm)  aphanitic extrusive felsic clast, ~5-9 mm in size 6 3  clast 14  albite or oligoclase  plagioclase or quartz  low relief with low interference colours; fine grained and infilling all spaces, occasional larger crystal is present (~0.05 mm in size)  34.4 (continued)  197  T/S #  Sample #  %Modal 4  Mineral carbonate  Mineral Description variable relief with high interference figures and distinct cleavage; anhedral up to 0.04 mm in size  2  plagioclase  1  chlorite  low interference colours and low relief; anhedral equant grains (0.4~2 mm in size). Subrounded, subangular or poikilitic with diffuse boundaries. Polysynthetic and simple twinning visible. green in PPL with high relief; flakes and sprinklees randomly oriented occurring throughout slide  plagioclase or quartz  low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass  3  carbonate  2  muscovite  variable relief and distinctive interference colours; irregular aggregates or single crystals (~0.1x0.4 mm in size), single crystals occur in irregular shapes, some are poikilitic low relief with distinct interference colours; small flakes randomly oriented throughout  1  epidote  1 1  chlorite opaques  fine grained matrix: 15% 7  high relief with high interference colours; fine grained globular texture, could be mistaken for oxides at high mag green in PPL; small flakes and sprinkles present, evenly distributed little black opaques, anhedral  198  T/S #  Sample #  26  285.6  clast 10  %Modal  Mineral  Mineral Description  meta-conglomerate: matrix supported with clasts extremely deformed, boundaries are difficult to distinguish between clasts and surrounding matrix porphyritic clast with plagioclase displaying perthitic 30 clast 10 texture 15 clast 17 aphanitic extrusive felsic clast 12 clast 19 chert 10 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 3 grain 3 single grains of untwinned plagioclase 30 matrix see description below porphyritic clast with perthitic texture; these clasts have begun to disaggregate and hold no clear boundaries between the matrix and the clast low relief with low interference colours; fine grained and plagioclase or infilling all spaces, occasional larger crystal is present 20 quartz (~0.05 mm in size) variable relief with high interference figures and distinct cleavage; euhedral up to 0.08-0.2 mm, occur in single 10 carbonate crystals or in aggregate patches up to 4x1 mm These carbonate crystals could be mistaken for replacing euhedral phenocrysts, but the carbonate itself is euhedral and cannot reflect the shape of any original minerals.  clast 17  clast 19  clast 16  grains 3a  aphanitic extrusive felsic clast, ~9x2 mm; partial clast, continued out of view off thin section and heavily metamorphosed  7  muscovite  low relief and high interference figures; somewhat aligned flakes and blocks throughout clast, concentrated in aggregates (possibly replacing former phenocrysts?) and flattened  4 2  plagioclase or quartz chlorite  low interference colours and low relief; fine grained aggregates green in PPL, small unaligned flakes throughout clast  2  black oxide  anhedral to euhedral blocks of "fuzzy" masses, skeletallooking  chert, large ~2 mm plagioclase or low interference colours with low relief; interlocking 12 quartz texture with crystals ~0.04 mm in size aphanitic mafic volcanic clast with aggregates of oxides, 8 mm, anhedral and looking stretched into different directions 7  muscovite  fine grained muscovite flakes, somewhat aligned  3  black oxide  small oxide spots, black powder ubiquitous  3  plagioclase  low interference colours and low relief; anhedral equant grains (~2 mm in size). untwinned  fine grained matrix: 30% 8  plagioclase or quartz  12  carbonate  4  muscovite  3  chlorite  low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass variable relief and distinctive interference colours; irregular aggregates or single crystals (~0.1x0.4 mm in size), single crystals occur in irregular shapes, some are poikilitic low relief with distinct interference colours; small flakes randomly oriented throughout green in PPL; small flakes and sprinkles present, evenly distributed  199  T/S # 26  Sample #  %Modal  Mineral  Mineral Description  285.6 (continued) 3  opaques  little black opaques, anhedral  200  T/S #  Sample #  27  248  %Modal  Mineral  Mineral Description  meta-conglomerate: matrix supported with small clasts (~2 mm)  high chloritization: 25% 15  plagioclase or quartz  low interference colours with low relief; interlocking texture with crystals ~0.04 mm in size  10  chlorite  low relief and green in PPL; fibrous and forming in anhedral shapes (~0.8 mm in size) within the felsic clasts  The 2 above minerals are pervasive throughout the slide in lenticular aggregates. fine grained matrix: 75% 35  chlorite  23 9  muscovite plagioclase or quartz  5 3  chlorite opaques  low relief and green in PPL; fibrous and forming in anhedral shapes (~0.8 mm in size) within the felsic clasts low relief with distinct interference colours; small flakes randomly oriented throughout low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass green in PPL; small flakes and sprinkles present, evenly distributed little black opaques, anhedral  201  T/S #  28  Sample #  %Modal Mineral Mineral Description meta-siltstone; equigranular with several thin felsic veins (~0.16 mm in thickness) of crystals coarser than the host rock. Some very thin dark linear features (~0.08 mm) 26a transect the slide as well and could possibly denote beds (?). overall slide mineralogy low interference colours with low relief; anhedral crystals ranging from mostly fine grained to ~0.08 x0.08 mm in plagioclase or size, with occasional larger anhedral single crystals 83 quartz (~0.02x0.03 mm). green pleiochroic, moderate relief, low interference colours; occurs in single randomly oriented needles (~0.02 mm in length) or elongate anhedral masses (~0.5x0.2 mm). One section of the slide shows skeletal-esque form of chlorite, 3 chlorite with fine grained plag/qtz. low interference colours with low relief; occur as larger crystals in the slide; only interference figures were obtained for the larger cyrstals and are mostly plagioclase (biaxial). plagioclase or Larger crystals can be single random crystals or patchy 8 quartz aggregates. 2 carbonate distinct twinning and interferece colours: forming in veins occurs in grey anhedral clumps (~0.08 mm in size) as well 2 epidote as small laths within the matrix grey powder concentrated in several areas: possibly a 2 opaques replacement feature? reconstructed mineralogy Judging by the small grain size and felsic composition, this rock before metamorphism was a siltstone. But this contradicts the dark colour of the slide in PPL and the presence of so many opaques.  202  T/S #  29  Sample #  %Modal Mineral Mineral Description meta-sandstone inequigranular, idioblastic, massive, several veins transect section, ~0.2 mm in thickness (largest 0.8 mm in thickness). These veins make up ~1% of slide. Veins contain plag/quartz and carbonate. A contact is displayed in one corner of the slide that 26b separates the metasedimentary rock from a coarser grained layer. overall slide mineralogy low interference colours with low relief; anhedral crystals ranging from mostly fine grained to ~0.08 x0.08 mm in plagioclase or size, with occasional larger anhedral single crystals 75 quartz (~0.02x0.03 mm). green pleiochroic, moderate relief, low interference colours; occurs in single randomly oriented needles (~0.02 mm in length) or elongate anhedral masses (~0.5x0.2 mm). One section of the slide shows skeletal-esque form of chlorite, 10 chlorite with fine grained plag/qtz. low interference colours with low relief; occur as larger crystals in the slide; only interference figures were obtained for the larger cyrstals and are mostly plagioclase (biaxial). plagioclase or Larger crystals can be single random crystals or patchy 5 quartz aggregates. distinct twinning and interferece colours: anhedral aggregates of several crystals (~0.2x0.4 mm), randomly 4 carbonate appearing within slide, usually associated with chlorite occurs in grey anhedral clumps (~0.08 mm in size) as well 3 epidote as small laths within the matrix grey powder concentrated in several areas: possibly a 2 opaques replacement feature? euhedral, prismatic, strongly pleiochroic blue-green length fast, straight exctinction, 1st order orange-blue, beginnings <1 biotite? of alteration seen; only 2 seen in slide There is also a contact seen within the slide that separates the main unit (described above) from it, possibly a large mafic clast. This smaller unit contains chlorite (~35%) with coarser grained plagioclast/quartz crystals (up to 0.4x0.4 mm) in addition to fine grained plagioclast/quartz. Many grains are twinned (albite or oligoclase). There are grains of epidotes (~0.12 mm, equant) as well as masses of epidote. The two different units are separated by a black cryptocrystalline layer of minerals of unknown composition; it ranges in thickness from ~0.15-0.4 mm. reconstructed mineralogy Due to the abundance of felsic minerals (plagioclase and quartz), the original rock before metamorphism was sedimentary, possibly fine-grained sandstone.  203  T/S # 30  Sample # %Modal Mineral Mineral Description meta-conglomerate: clastic (subrounded-subangular felsic and mafic clasts set in a finer 23a grained matrix) Below is the distribution of the clasts and grains within the thin section. Following this are the detailed descriptions of the various clasts and grains. Minerals are listed in order of abundance. 12 grain 3 single graines of plagioclase and quartz 7 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 3 clast 1 mafic hypabyssal clast with subophitic texture 3 clast 3 granite clast 3 clast 20 chert <1 grain 1 mica-rich single grain <1 grain 4 dark oxide mass with tails 70 matrix see description below Single plagioclase and single quartz that are presumed to have originated from the granite clasts and have been disaggregated from them. The following features are visible in some crystals: bent albite twinning, oscillatory extinction, jigsaw puzzle texture, poikilitic texture, antiperthitic grain 3 12 texture. clast 16  aphanitic mafic volcanic clast with aggregates of oxides, ~8x5 mm 4  muscovite  fine grained muscovite flakes, somewhat aligned  2-4  black oxide  small oxide spots, black powder ubiquitous  clast 1  mafic hypabyssal clast with subophitic texture low relief, 1st O yellow colours, simple twinning visible; 0.5 plagioclase euhedral laths plagioclase or anhedral crystals occurring between yellow plag laths 0.4 quartz (~0.1x0.1 mm) 0.1 opaques black dust, occurs ubiquitously throughout clast Some muscovite flakes and aggregates (up to 0.05%) and occasional graines of epidote (euhedral laths, ~0.5 mm in length also are present. This is speculated to originally to have been a mafic clasts because of the black oxide dust and criss-crossing plagioclase texture, indicating volcanic formation.  clast 3  rounded granite clast ~4x2 mm low interference colours, polysynthetic and carlsbad twinning, biaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to sub-angular with evidence of broken crystals. Twinning is seen in some crystals and some appears bent at a shallow angle. Larger crystals can contain albite or 2 oligoclase small (~0.3x0.1 mm) inclusion of a mineral. An5 or An20. low interference colours, low relief, uniaxial; ranges in size from ~0.2x0.2 mm up to 1.5x1.7 mm, sub-rounded to subangular with evidence of broken crystals and oscillatory zoning. Larger crystals can contain small (~0.3x0.1 mm) 1 quartz inclusion of a mineral. Single plagioclase and single quartz that are presumed to have originated from the granite clasts and have been disaggregated from them are included in this category. Bent polysynthetic twinning visible in crystals. Some antiperthitic texture visible. chert, large ~4 mm plagioclase or low interference colours with low relief; interlocking 3 quartz texture with crystals ~0.04 mm in size  clast 20  These clasts contain some small ~0.08 mm in length sprinkles of muscovite. There are also high relief minerals (mafic minerals?) present. Due to its fine grained nature, this clast possibly is chert. 30  23a (continued)  204  T/S #  Sample # grain 1  %Modal  Mineral Description  mica-rich single grain, ~1.5 mm  <1 grain 4  Mineral  mica  muscovite? pyrophyllite? low-moderate relief, high interference colours (2nd O yellow - 3rd O green), parallel extinction; flakes and distorted tabs (~0.05 mm in length)  dark replaced volcanic clast 0.08  oxide  0.02  rutile  black and patchy in both PPL and XPL, displays heterogeneity high relief, high interference colours; small needles (~0.01 mm)  This grain is rounded with tails extending in opposite directions. This is suggested to be a volcanic grain due to the presence of titanium. interclast matrix (70%) plagioclase or low relief, low interference colours, mostly polysynthetic 55 quartz twinning; fine grained with interlocking texture low relief, distinct interference colours; single laths or fine grained elongate masses are seen, crystals range from being 10 muscovite randomly oriented to oriented reddish brown to brown (in both PPL and XPL), anhedral 8 opaques masses (~0.08mm-0.1 mm in size) 2 opaques completely black, forms anhedral masses (~0.05 mm)  205  T/S # 31  Sample # %Modal Mineral Mineral Description 23b meta-conglomerate: clastic with broken and poikilitic clasts, carbonate-rich Below is the distribution of the clasts and grains within the thin section. Following this are the detailed descriptions of the various clasts and grains. Minerals are listed in order of abundance. 15 grains 3 plagioclase and quartz 5 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 4 clast 1 mafic hypabyssal clast with subophitic texture 4 clast 20 chert 1 clast 8 porphyritic mafic extrusive clast 1 clast 9 porphyritic felsic hypabyssal clast 1 clast 15 mafic extrusive clast 69 matrix see description below aphanitic mafic volcanic clast with aggregates of oxides, irregulat and elongate shape, clast 16 ~2x4 mm 2-4 muscovite fine grained muscovite flakes, somewhat aligned 3 black oxide small oxide spots, black powder ubiquitous Chlorite is present (~1%) in flakes, with anhedral carbonate crystals (~0.05x0.05 mm). Secondary oxides (hematite?) may be present around some black oxide crystals. clast 1  mafic hypabyssal clast with subophitic texture, ~4 mm in length, elongate and flattened low relief, 1st O yellow colours, simple twinning visible; 2 plagioclase euhedral laths (~0.8x0.3 mm) plagioclase or anhedral crystals occurring between yellow plag laths 1 quartz (~0.1x0.1 mm) 1 opaques black dust, occurs ubiquitously throughout clast These clasts contain tiny slivers of chlorite (~3%), flakes of muscovite (~1%), and some serpentine alteration visible (green in PPL with low interferenc colours, low relief, and a mottled appearance).  clast 20  chert, elongate, 4-12 mm in length plagioclase or low interference colours with low relief; interlocking 4 quartz texture with crystals ~0.04 mm in size These clasts contain some small ~0.08 mm in length sprinkles of muscovite (up to 10%). There is also up to 10% anhedral carbonate crystals (~0.01x0.02 mm).  clast 8  porphyritic mafic extrusive clast; 7x2 mm, soft deformation?  0.4  0.45 0.1  clast 9  plagioclase  low interference colours with low relief; large equant grains (~0.2x0.05 mm), randomly oriented, some simple twinning  chlorite black oxide  green in PPL, low interference colours; fine grained aggregates throughout clast, individual texture unseen anhedral to euhedral blocks of "fuzzy" masses  low interference colours with low relief; flakes randomly 0.05 muscovite oriented porphyritic felsic hypabyssal clast; 10x6 mm in size, oblong 0.6  0.2  plagioclase  low interference colours with low relief; fine-grained form that makes up the groundmass within this clast  plagioclase  low interference colours with low relief; large crystals, up to 0.4 mm, equant to irregular shapes ~1-2 mm in size, some crystals simply twinned and others poikilitic  206  T/S # Sample # %Modal 31 23b (continued)  clast 15  grain 3  grain 3a  Mineral  Mineral Description  0.1  carbonate  variable relief with high interference figures; irregular crystal shapes ~0.3 mm in size, possibly replacing some original mineralogy  0.1  black opaque  black dust, occurs ubiquitously throughout clast  mafic extrusive clast, 9x2 mm with tapering end; partial clast, continued out of view off thin section 0.35 0.25  plagioclase or quartz chlorite  low interference colours and low relief; fine grained aggregates green in PPL, masses, infilling rest of texture  0.1  plagioclase  low interference colours and low relief; crystals ~0.2 mm in length in laths and equant shapes  0.1 0.1 0.05  carbonate chlorite muscovite  variable relief with high interference figures; anhedral up to 0.2 mm, occuring in single crystals (small and rounded) and in aggregates (larger and more angular) green in PPL with high relief; small flakes low relief; unaligned flakes  0.1  black oxide  anhedral to euhedral blocks of "fuzzy" masses  single grains of plagioclase and quartz, mostly equant and subrounded low interference colours and low relief; anhedral equant grains (~0.02-2 mm in size). untwinned and/or poikilitic 8 plagioclase plagioclase: 3a; quartz: 3b, some aggregates seen  grain 3b grain 3c  5 2  disaggregated grains  low interference colours and low relief; ~0.02-1.5 mm in quartz size, confirmed uniaxial albite polysynthetic twinning; An15-25, ~0.8 mm This thin section and thin section number 23a are cut from the same rock sample. Number 23a (which contains granite clasts not seen in this thin section), are speculated to be the source of the single plagioclase and quartz grains, which have been disaggregated from them. The following features are visible in some crystals: bent albite twinning, oscillatory extinction, jigsaw puzzle texture, poikilitic texture, antiperthitic texture.  interclast matrix plagioclase or quartz  30  calcite  34  muscovite  4  brown opaque  3  opaques  low relief, low interference colours, mostly polysynthetic twinning; fine with grained with interlocking texture variable relief distinctive interference colours; all thoughout slide, occurs as anhedral crystals, single and aggregates present, largest crystals ~0.8 mm in length. Occurs in fractures of crystals and as inclusions in oikicrysts low relief, distinct interference colours; single laths or fine grained elongate masses are seen, crystals range from being randomly oriented to oriented "haloes" present around some black opaques, possibly hematite alteration? ~0.02 mm sized and equant; associated with clast 7s, mostly homogenous w/few crystals displaying fuzzy brown texture  207  T/S # 32  Sample #  %Modal Mineral Mineral Description transition between conglomerate and volcanic layers? inequigranular, hypidioblastic, 14 several veins transect slide 5 clast 21 globular ultramafic clast encompassing plagioclase laths 5 clast 20 chert 4 clast 1 mafic hypabyssal clast with subophitic texture 78 matrix see description above 3 veins see description above vein mineralogy (3%): ranging from 1-4 mm in thickness plagioclase or 3 quartz finer grained (crystals ~0.08 mm in size), mosaic texture Veins can contain up to 4% of carbonate crystals. Other carbonate within the slide is concentrated around the edges of the veins. Also, the veins contain ~1% of chlorite and muscovite flakes somewhat aligned in the direction of the vein (0.01-0.05 mm in length). The muscovite also occurs in tabular crystals (0.1x0.05 mm). A very thin vein (0.04 mm in thickness) is also present within the thin section. interclast low relief with low interference colours; crystals range from plagioclase or 0.04-0.4 mm in size; simple and polysynthetic twinning 45 quartz seen in plagioclase, occurs throughout slide  25  carbonate  5  epidote  3  muscovite  variable relief and distinctive interferenc colours; irregular aggregates of single crystals (~0.01 mm in size), concentrated around veings, but evenly distributed throughout rest of slide. Single crystals occur in irregular shapes, some are poikilitic extremely high relief, 2nd O interference colours; small aggregates up to 0.02 mm in size, oblong and anhedral growth blobs, randomly distributed low relief, higher interference colours; small flakes in random orientation green in PPL, low interferenc colours; occurs as flakes/sprinkles (~0.01 mm in length), randomly oriented  2 chlorite clast mineralogy: 10% clast 21 globular ultramafic clast encompassing plagioclase laths; ~4 mm in size, rounded 5 chlorite green in PPL, low interference colours Can contain up to 1% of muscovite mica flakes and some globular epidote present. clast 20 chert, ~0.8 mm, lenticular shape plagioclase or 5 quartz fine-grained plagioclase or quartz with a mosaic-like texture These clasts contains up to 10% chlorite flakes. clast 1  mafic hypabyssal clast with subophitic texture, ~4 mm in length, elongate and flattened low relief, 1st O yellow colours, simple twinning visible; 2 plagioclase euhedral laths (~0.8x0.3 mm) plagioclase or anhedral crystals occurring between yellow plag laths 1 quartz (~0.1x0.1 mm) 1  opaques  black dust, occurs ubiquitously throughout clast  The outlines of these clasts are not well defined and commonly cannot be distinguished from the groundmass of this thin section if not for the areas of visible plagioclase texture. 33  altered volcanic clast: equigranular, fine-grained, slight foliation visible and there is a 4 large vein (~2 mm in thickness) along side of thin section vein mineralogy (5%)  208  T/S #  Sample #  %Modal  Mineral  Mineral Description  grey interference colours with low relief; small (~0.04x0.03 plagioclase or mm) to large (~0.4-0.3 mm) anhedral grains, displaying 2 quartz mosaic texture in some areas, some are poikilitic Larger grains are confirmed as quartz (by a uniaxial interference figure), but smaller grains are difficult to distinguish. extremely high interference colours with distinct cleavage; anhedral masses with crystals ranging in sizes (~0.05-0.07 1 carbonate mm), sometimes enclosed by brown opaques preferentially associated with carbonate, forms anhedral 0.5 brown opaque masses with a grainy texture tiny slivers (~0.01-0.02 mm in length), medium relief, slightly green in PPL with 3rd order interference colours; 0.5 chlorite sprinkled throughout variable relief with extremely high interference colours; anhedral crystals (~0.8x0.1 mm), present in cpx and plag oikicrysts  1 carbonate overall mineralogy (95%, excluding vein) plagioclase or grey interference colours with low relief; fine grained 70 quartz texture and massive in the grounmass extremely high interference colours with distinct cleavage; larger crystals in the groundmass (~0.2-0.4x0.3-0.4 mm), anhedral equant-elongate in shape, single crystals are 10 carbonate present in addition to aggregates 7 brown opaque see description above 5  chlorite  see description above colourless in PPL, bird's eye extinction with low relief; forms "tendrils" that are somewhat oriented in the same 3 muscovite direction The above mineralogy describes the thin section as a whole. The distribution of these minerals, however, manifest themselves in several aggregates present in a groundmass of smaller sized crystals of the same minerals. extremely high interference colours with variable relief; aggregate 1 90 carbonate anhedral, ~0.1-0.3 mm in size and random plagioclase or 8 quartz see description above 1 brown opaque see description above 1 black opaque black dots seen  209  T/S # Sample # %Modal Mineral Mineral Description 33 4 (continued) These aggregates are the most abundant (~1x0.5 mm) and are somewhat anhedral. Some aggregates seem as if they have a diamond or rectangular shaped outline, but it is not clear. Due to the difficulty in determing the shape of the original crystal, speculating what has been replaced is largely subjective. These aggregates can also contain up to 0.5% of small mica slivers along the edges that are aligned. plagioclase or low interference colours with low relief; fine grained with aggregate 2 50-80 quartz mosaic-like texture 8-10 carbonate see description above These aggregates are oblong shaped and anhedral ranging in sizes, ~0.8x0.25 mm ~1.0x0.5 mm, up to 4.0 mm in length. Some "sprinkles" of chlorite are present in some areas. Due to the presence of a euhedral shape, I speculate these aggregates were originally pyroxene or olivine. Sometimes muscovite is present (up to 0.5%). aggregate 3  95 brown opaque 5 carbonate  cryptocrystalline, anhedral, matte texture see description above  This aggregate forms in anhedral shapes. It is difficult to determine what is has replaced, possibly biotite? reconstructed mineralogy Because of the presence of replaced mafic minerals, in addition to its fine grained and equigranular texture, I would infer this rock was formerly volcanic. Due to the difficulty in determining the original shape of the original phenocrysts, I can only speculate the rock contained pyroxenes and olivines (i.e. a mafic rock).  210  T/S #  Sample #  34  13a, 13c  %Modal Mineral Mineral Description plagioclase rich subvolcanic dyke: inequigranular, porphyroblastic texture with pseudomorphs  porphyroblasts (10%) The porphyroblasts are not monominerallic and consist of the following minerals. brown pleiochroic with distinct interference colours; tabular crystals (~0.05-0.1 mm), randomly oriented with an7 biotite euhedral forms slightly green pleiochroic with moderate relief, but very low interference colours; euhedral acicular crystals randomly 2 chlorite oriented 1st order grey and yellow with high relief; small (~0.011 epidote 0.02 mm) crystals in tabular or subhedral forms The porphyroblasts range in size, averaging ~0.2-0.8mm and up to 2.0x1.0 mm. Most of them display euhedral with rectangular forms and can contain ~0.5-1.0% of carbonate crystals. Based on the euhedral and rectangular shapes of the original crystals that have now been replaced, it is likely they were plagioclase crystals. fine grained matrix (90%)  30 30  biotite plagioclase or quartz  15  epidote  15  chlorite  5  carbonate  5 black opaque reconstructed mineralogy  slightly brown pleiochroic with high interference colours; occur as small crystals (<0.05 mm) that are evenly dispersed in the matrix low relief with low interference colours, interstitial between all other matrix minerals very high relief; globular forms, ubiquitous in the background, could be mistaken for oxides unless viewed at higher power moderate relief, low interference colours; occur in flakes ~0.02 mm, randomly oriented variable relief with extremely high interference colours; occur as small crystals (<0.05 mm) or as larger masses (~0.01x0.01 mm) black equant euhedral (up to 0.05 mm in size), occasionally occur in clusters  I infer this rock originally was a mafic dyke. This is based on the amout of epidote present, which is a common alteration mineral after mafic minerals. In addition, the replaced plagioclase crystals and original prophyritic texture support this.  211  T/S # 36  Sample #  %Modal Mineral Mineral Description meta-peridotite: inequigranular, porphyroblastic: serpentinized larger crystals with 21 interstitial minerals overall slide mineralogy slightly green pleiochroic with low 2st order interference colours; fibrous forms in subparallel rows or in irregular 35 chlorite radiating patterns high relief with inclined extinction: occur as either anhedral block-elongate shapes with variety of sizes (0.05x0.13 mm to 0.70x0.30 mm) or euhedral grains, large (1.7x1.3 mm); in process of being replaced, evidenced by biotite and 25 clinopyroxene serpentine at edges and in patches within the crystal high interference colours with medium relief; occur as either primary anhedral interstitial shapes (~0.12-0.21 mm) 20 talc in 2 forms or as powder, assicated with serpentine brown pleiochroic with high interference colours; interstitial, forming large irregular crystals (~1-2 mm at longest points) sometimes durrounding serpentine; "matte" 15 biotite texture in PPL (due to alteration?) occur as dots, oblong shapes, and "lines" throughout slide; 5 opaques associated with fractures in crystals The above list is representative of the entire slide's mineralogy; below is the distribution of some of these minerals: the serpentine and some talc manifest in aggregates. Below is a description of the pseudomorphs. aggregate 1  98 serpentine? see description above 2 oxide "dots" see description above Fine and fibrous serpentine replaced large (~2.00-3.00 mm) crystals. Cracks that run through the crystal are visible. Based on the euhedral shape with 120˚ outer angles and distinctive cracks, the serpentine has replaced olivine. I predict it is not pyroxene as other pyroxenes are still present within the sample. Sometimes small (~0.1-0.2 mm) talc inclusions are present, up to 4%, in primary anhedral shapes.  reconstructed mineralogy It is predicted that the original rock was troctolite due to the coarse grained texture of the slide, and if my predictions are correct about the pseudomorphs, this rock originally contained the proper estimated proportions of pyroxene and olivine. No remnant rectangular shapes seen, indicating no original plagioclase presence.  212  T/S # 37  Sample #  %Modal Mineral Mineral Description meta-sandstone: equigranular, a few large clasts with a majority of smaller clasts within a 22a fine-grained matrix 18 clast 19 chert 20 grains 3 single plagioclase and quartz crystals 1 clast 16 aphanitic mafic volcanic clast with aggregates of oxides 1 clast 14 porphyritic rhyolite 60 clast 21 globular ultramafic clast encompassing plagioclase laths 60 groundmass see description above clast mineralogy: 40% clast 19  chert, ~0.5-2 mm ovoid and rounded shape plagioclase or low interference colours with low relief; interlocking 15 quartz texture with crystals ~0.04 mm in size  These clasts contain some small laths and planks of chlorite (~1%). grains 3a single plagioclase crystals, 0.5-1mm, rounded plagioclase or 10 quartz low interference colours with low relief grains 3b single quartz crystals, ~0.5-1 mm in size; rounded plagioclase or 10 quartz low interference colours with low relief Chlorite is present as laths with anomalous blue interference colours. clast 16  clast 14  clast 21  aphanitic mafic volcanic clast with aggregates of oxides, irregularly shaped, ~3x1 mm in size; soft deformation seen 2-4 muscovite fine grained muscovite flakes, somewhat aligned 3 black oxide small oxide spots, black powder ubiquitous Chlorite is present (~1%) in flakes, with some globular epidote (?). porphyritic rhyolite; arrowhead shaped ~4x2 mm in size with one quartz phenocryst low interference colours with low relief; fine grained, indistinct crystals in the matrix of this clast, crystal size varies throughout clast in patches or very small rounded plagioclase or clasts, some plagioclase texture similier to volcanic 0.95 quartz groundmass green in PPL with high relief; randomly oriented flakes and 0.04 chlorite occasional laths low interference colour with low relief; euhedral octagonal 0.1 quartz shape, uniaxial positive, ~0.4x0.4 mm in size 0.01 epidote? high relief; globular forms globular ultramafic clast encompassing plagioclase laths: (~0.08 mm) 1  dark oxides  fine grained  40  plagioclase or quartz  8  muscovite  8 2 2  epidote? hematite opaques  low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass low relief with distinct interference colours; small flakes randomly oriented throughout high relief with high interference colours; fine grained texture, could be mistaken for oxides at high mag reddish brown in PPL, anhedral blebs ~0.02 mm in size little black opaques, anhedral  fine grained matrix 60%  213  T/S # 38  Sample #  %Modal Mineral Mineral Description meta-sandstone: inequigranular, a few large clasts with a majority of smaller clasts within 22b a fine-grained matrix single untwinned plagioclase, single quartz, and twinned 35 grains 3a, b, c plagioclase grains 5 clast 20 chert 3 clast 3 granite clast 57 groundmass see description below clast mineralogy: 40% grain 3a, b, single untwinned plag, single quartz, and twinned plag; upt to 0.4 mm in size w/ average c sizes ~0.08-0.2 mm low interference colours with low relief; some plag plagioclase or untwinned or with simple twins, all may display poikilitic 35 quartz forms and oscillatory extinction  clast 20  clast 3  Most of these clasts are too small to obtain interference figures, but are presumed to be representative of the clasts that were able to be determined as biaxial or uniaxial. Occasional slivers of chlorite present. finer-grained felsic clast w/ mafics; flattened oblong shapes with ragged boundaries, ~0.4x0.1 mm and ~1x2 mm plagioclase or 5 quartz low interference colours with low relief; small grains These clasts contain some small laths and planks of chlorite and muscovite (~1%). rounded granite clast ~0.2x0.08 mm low interference colours, polysynthetic and carlsbad albite or 2 oligoclase twinning, biaxial; An5 or An20. 1 quartz low interference colours, low relief, uniaxial; Single plagioclase and single quartz that are presumed to have originated from the granite clasts and have been disaggregated from them are included in this category. Bent polysynthetic twinning visible in crystals. Some antiperthitic texture visible.  vein mineralogy 3% felsic veins: sinuously cutting through conglomerate, post-metamorphic event due to unoriented aluminosilicates plagioclase or 3 quartz low interference colours with low relief Muscovite laths and large flakes (~0.05 mm) are present up to ~15% of the bed/vein. Anhedral opaques are also present, displaying poikilitic texture, up to ~0.2x0.4 mm in size. Vesicles present. fine grained matrix 57% plagioclase or 40 quartz 5 muscovite 5  epidote?  3 2 2  chlorite hematite opaques  low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass low relief with distinct interference colours; small flakes randomly oriented throughout high relief with high interference colours; fine grained globular texture, could be mistaken for oxides at high mag green in PPL; small flakes and sprinkles present, evenly distributed, blue anomalous interference colours? reddish brown in PPL, anhedral blebs ~0.02 mm in size little black opaques, anhedral  214  T/S #  Sample #  39  5  %Modal  Mineral  Mineral Description  metamorphosed pillow basalt: equigranular texture, porphyritic, oxide-rich, massive This pillow basalt displays a porphyritic texture with 2 different types of phenocrysts: one has has been replaced by muscovite and the other replaced with a darker mineral (biotite? chlorite?). high interference colours, low relief, no pleiochroism; 30 muscovite anhedral and massive, fine grained throughout slide Some, ~5%, of talc is replacing a former phenocrysts. Judging by the elongate and euhedral shape, the replaced mineral is probably plagioclase, formerly making up ~3% of the slide. These replaced phenocrysts are laths ~0.8x0.4 mm in size.  10  biotite? chlorite?  medium relief, brown in PPL; forming in small aggregates of prismatic forms, ~0.4x0.2 mm in size  This minerals is replacing a former phenocrysts, making up about 5% of the phenocrysts. It is difficult to predict what mineral it is replacing.  25  plagioclase and low relief with low interference colours; forms in lenticular quartz forms ~2 mm in length, anhedral interlocking texture  22  carbonate  variable relief with extremely high interference colours; 0.1 mm in size, sub-euhedral forms  6  opaques  4  chlorite  1  rutile  black, very small ~0.2 mm anhedral blobs, some red colour seen (hematite?) green in PPL, low interference colours; small ~0.01 mm, random flakes in no specific orientation very high relief, high interference figures; ~0.02 mm in length, flakes  215  T/S #  Sample #  40  17  %Modal  Mineral  Mineral Description  diabase dyke: equigranular, hypidiomorphic, little alteration visible  overall slide mineralogy  49  plagioclase (andesine)  45  clinopyroxene  5  opaques  1  biotite  low interference colours with distinct twinning; distinc laths, twinning present in most crystals (carlsbad, albite, or both), randomly oriented, most are 0.4-1.3 mm, but can be up to 1.7 mm. An47 inclined extinction with 2nd order interference colours; anhedral variable eshapes from equant to elongate, present between plag crystals, evenly distributed with some simple twinning seen eu-subhedral blocks evenly dispersed, ~0.13-0.5 mm size; biotite present with opaques (possibly replacing opaques?) green-brown pleiochroic with high interference colours; up to 0.23 mm in length, present with opaques (possibly replacing opaques?)  Except for biotite, all other minerals present are primary. 5-10% of the clinopyroxene volume is altered to biotite. This alteration occurs along margins of the crystals; the biotite replacement retains the shape of the original clinopyroxene crystals  216  T/S #  41  Sample #  19a  %Modal  Mineral  Mineral Description  bedded meta-argillite: fine grained, some crenulation cleavage (microfolds) seen, foliation is cross-cutting what is inferred to be original bedding @~60/120˚, in addition to serpentine veins being present.  The following mineral descriptions are of the currently mineralogy in the slides. There are no replacement textures seen. plagioclase possibly with low relief with low interference colours; fine grained 80 quartz crystals with interlocking textures make up most of the slide high relief with low grey interference colours; flakes are 9 chlorite? aligned in direction of cleavage (and not original bedding) distinctive interference colours with low relief; also lined 6 muscovite up in direction of cleavage (and not original bedding) associated with the muscovite and chlorite; helps define the 3 brown oxide crenulation cleavage powder-like forms, also associated with the muscovite and 2 black oxide chlorite reconstructed mineralogy This sample contains features that can be inferred to be original bedding, indicating it was previously a sedimentary rock. In addition, the amount of plagioclase and quartz present supports this. Original bedding is seen clearly and occurs as irregular linear features sinously transecting slide. No infill has occurred and these separations are only voids (clear in PPL and black in XPL). The foliation manifests as features cross-cutting original bedding at ~60/120˚: it occurs as muscovite flakes that are aligned and overlapping each other.  217  T/S #  Sample #  42  19b  %Modal Mineral Mineral Description meta-siltstone: inequigranular, clastic (aggregates and single crystals present as clasts) in a finer grained matrix, slightly foliated  overall slide mineralogy  40  20  25 7  3  low interference colours, twinning seen in some crystals: albite or larger single crystals present (~0.04-0.4 mm in length), oligoclase anhedral The plagioclase only displays enough zoning to determine approximate An composition, but further constraint is difficult because of the small size of the crystals. The anorthite content is either An5 or An25, hence it is either albite or oligoclase. low interference colours and low relief; fine grained and plagioclase makes up most of the matrix, appear as aggregates with a possibly with mosaic-like texture, mostly ~0.3x0.2 mm with aggregates quartz up to 0.5x1 mm in size, some twinning seen low relief with high interference colours; aligned flakes are present and seem to "wrap" around aggregates and single muscovite larger crystals of plagioclase and quartz high relief and green in PPL with slight yellow-green chlorite pleiochroism; occurs as aligned flakes with muscovite low interference colours, low relief, uniaxial; larger single crystals within the matrix, mostly ~0.4x0.35 mm and can be single quartz up to 0.8 mm in length, oscillatory extinction, anhedral  These single crystals of quartz are interspersed in the thin section and randomly oriented. At the edges of some crystals, some muscovite microliths are encroaching into it, but most of the muscovite "wraps" around the it. 3 brown oxide associated with the muscovite and occur in random patches 2 black oxide random patches in the thin section (~0.1 mm in size) reconstructed mineralogy Judging on the composition of the rock (~20% sand, ~80% mud or silt), the parent rock of this sample was sedimentary. Also, the lack of chlorite indicates it did not have a mafic volcanic origin.  218  T/S # 43  Sample # %Modal Mineral Mineral Description 20a meta-conglomerate: multiminerallic clasts set in matrix Below are descriptions of different types of clasts and their replacement mineralogy and textures. The slide itself is divided into two sections: a mafic side and a felsic side. Each clast described below is defined as being present on one side, or both. All clasts do not have sharp boundaries between itself and the groundmass; all outlines are diffuse. 6 clast 20 chert 5 clast 23 ultramafic clast with globular epidote 2 grain 3 plagioclase and quartz grains 1 clast 1 mafic hypabyssal clast with subophitic texture 1 clast 6 porphyritic mafic clast <1 grain 1 replaced mafic mineral <1 grain 2 mineral replaced by amphibole 85 matrix see description below clast 20  clast 23  clast 1  clast 6  chert, subrounded (up to ~2x2 mm) plagioclase or low relief and low interference colours; anhedral, mosaic6 quartz like texture, equant grains (from ~0.12-0.24 mm in size) These clasts can contain occasional subhedral grains of carbonate (up to 1%). Rounded ~2 mm in size with mostly plagioclase or quartz making up the clast. The minerals are irregular crystal shapes and not very well defined. Muscovite and chlorite sprinkles are present up to 1%, randomly oriented. Small (~0.04 mm) ultramafic clast with globular epidote (~1x0.75 mm) replaced mafic clast: present on both sides of thin section. Can contain up to 5% black oxides. very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other 4.5 chlorite characteristics high relief with high interference colours; "bubbly" aggregate form as well as elongate crystals (~0.05 mm in 0.5 epidote? length) mafic hypabyssal clast with subophitic texture (~2x2 mm): present only on mafic side low relief, 1st O yellow colours, simple twinning visible; 0.5 plagioclase euhedral laths plagioclase or anhedral crystals occurring between yellow plag laths 0.4 quartz (~0.1x0.1 mm) 0.1 opaques black dust, occurs ubiquitously throughout clast Some muscovite flakes and aggregates (up to 0.05%) and occasional grains of epidote (euhedral laths, ~0.5 mm in length also are present. This is speculated to originally to have been a mafic clasts because of the black oxide dust and criss-crossing plagioclase texture, indicating volcanic formation. porphyritic mafic clast (~2x1 mm): Displays original phenocrystic texture, but all replaced; thus being porphyroblastic. Mostly present on the mafic side, but protrudes slightly into the felsic side. plagioclase eu-subhedral tabular crystals (~0.25-0.2 mm) with muscovite and chlorite flakes (up to 50% of the 0.15 porphyroblasts porphyroblast) fine-grained plagioclase or quartz; low interference colours with low 0.08 matrix relief with fine grained texture 1. black oxide powder, evenly distributed across clast 2. 0.05 oxides black anhedral oxide There is a noticeable rim around this clasts; speculated to be a reaction rim of some sort.  219  T/S # 43  Sample #  %Modal  Mineral  Mineral Description  20a (continued) grain 1  replaced mafic mineral (~1x0.75 mm): present only on mafic side muscovite? pyrophyllite? low-moderate relief, high interference colours (2nd O yellow - 3rd O green), parallel <1 mica extinction; flakes and distorted tabs (~0.05 mm in length) grain 2 mineral replaced by amphibole: only present on mafic side slightly army green pleiochroic, 2nd order interference colours, moderate relief and length fast; radiating form (~2x2 mm) of many euhedral and anhedral glomeritic <1 amphibole? cyrstals; some plagioclase infilling between crystals This could have been a garnet grain, due to the radiating texture of the replacing mineral (reminiscent of kelyphitic rim?). grain 3: 2%: present on both sides low interference colours and low relief; anhedral equant grains 3a, plagioclase or grains (~0.4x0.4 mm in size). untwinned and/or poikilitic 3b 1.5 quartz plagioclase: 3a; quartz: 3b albite twinning and only 1 grain found; An10, single grain 3c 0.5 albite subhedral grain (~0.6x0.3 mm) 20 oxides powder and aggregates descriptions of groundmass (i.e. features that are not clasts) plagioclase or 78 quartz fine grained, makes up the majority of this side strongly pleiochroic, moderate relief, cleavage seen. only 0.5 biotite large grain seen 2-25 muscovite coloursless in PPL; ranges from single laths to aggregates aggregates of a high relief high interference colour mineral; 0.5 epidote? could be mistaken for oxide? Mafic Side: This side of the slide is very oxide-rich, so much so that it distinguishes itself from the other side. The majority of the replaced clasts only exist on this side. The 40% muscovite content grades from muscovite poor (~2%) to muscovite rich (~25%), laterally across the slide. Felsic Side: This section is mostly (~95%) plagioclast or quartz in a coarser grained 45% (compared to the mafic side) state. One area has large thick matted masses of a very low interference colour mineral (serpentine?) with flakes of a higher interference colour minters (muscovite? <1%). Muscovite is also present in the plagioclase or uartz matrix, up to 5%. A coarse grained vein traverses this section (~0.8 mm in thickness). Oxides are present, but not as much as the mafic side; there is little oxide powder but rather, darker anhedral oxide blobs, associated with vacancies in slide.  220  T/S #  Sample #  44  20b  %Modal  clast 2  grain 3a grain 3b clast 9  clast 16  Mineral Description  meta-conglomerate: coarse texture, clast supported with large clasts avg 3-4 mm in length 25  clast 18  chert  15  clast 2  mafic effusive clast with subophitic texture  8  grain 3a  untwinned plagioclase grain  5  grain 3b  single quartz grains  1 3  clast 9 clast 16  porphyritic felsic hypabyssal clast aphanitic mafic volcanic clast with aggregates of oxides  grain 3 clast 8 clast 7 clast 23 clast 3 groundmass  twinned plagioclase grain porphyritic mafic extrusive clast porphyritic mafic intrusive clast ultramafic clast with globular epidote granite clast see description below  3 3 1 0.5 0.5 35 clast mineralogy: 65% clast 18  Mineral  chert, subrounded (~2x1mm); finer-grained felsic clast w/ mafics; flattened oblong shapes and angular, ~7x2 mm; or plagioclase or low relief and low interference colours; anhedral, mosaic3 quartz like texture, equant grains (from ~0.12-0.24 mm in size) These clasts contain some small laths and planks of chlorite (~3%). Carbonate crystals are present as anhedral single or aggregated crystals (crystals ~0.4 mm). mafic effusive clast with subophitic texture; these plagioclase crystals range from thin laths (~4x2 mm) to acicular, spherulitic texture seen low relief, 1st O yellow colours, simple twinning visible; 8 plagioclase euhedral laths (~0.2x0.01 mm) plagioclase or anhedral crystals occurring between yellow plag laths 3 quartz (~0.1x0.1 mm) 2 opaques black dust, occurs ubiquitously throughout clast low interference colours and low relief; anhedral equant 8 plagioclase grains (~2-2 mm in size). untwinned low interference colours and low relief; ~3.5x2 mm in size, 5 quartz confirmed uniaxial porphyritic felsic hypabyssal clast; 10x7 mm in size, oblong  0.6  plagioclase  0.2  plagioclase  0.1  carbonate  low interference colours with low relief; fine-grained form that makes up the groundmass within this clast low interference colours with low relief; equant to irregular shapes ~0.5-0.8 mm in size, some crystals simply twinned, poikilitic variable relief with high interference figures; irregular crystal shapes ~0.3 mm in size, possibly replacing some original mineralogy  0.1 black opaque black dust, occurs ubiquitously throughout clast aphanitic mafic volcanic clast with aggregates of oxides, irregularly shaped, ~7x2 mm in size 2 muscovite fine grained muscovite flakes, somewhat aligned 1 black oxide small oxide spots, black powder ubiquitous Chlorite is present (~1%) in flakes, with some globular epidote (?).  44  22b (continued)  221  T/S #  Sample #  %Modal  grain 3c  3 7  Mineral albite or oligoclase plagioclase or quartz  Mineral Description polysynthetic twinning; An10-25, 1x1 mm and subrounded low interference colours with low relief; small indistinct grains  These clasts contain some small laths of chlorite (~1%). clast 8  porphyritic mafic extrusive clast; 7x2 mm, soft deformation? low interference colours with low relief; large equant grains 1 plagioclase (~0.5*0.8 mm), randomly oriented, simple twinning green in PPL, low interference colours; fine grained 1 chlorite aggregates throughout clast, individual texture unseen 0.5 black oxide anhedral to euhedral blocks of "fuzzy" masses 0.5  clast 7  clast 23  clast 3  chlorite  green in PPL with high relief; flakes randomly oriented  porphyritic mafic intrusive clast, ~3x5 mm: oblong with tapered points 1 0.5  plagioclase or quartz black oxide  0.5  carbonate  low interference colours with low relief; fine grained with indistinct crystals makes the black colour of clast varied relief with high interference colours; anhedral ~0.05 mm, flattened and evenly distributed  0.2  chlorite  colourless in PPL, low interference colours; flakes  ultramafic clast with globular epidote (~2x1 mm); flattened with tapered points  0.5  chlorite  0.5  granite clast  very dark in XPL, low interference colours, low relief; forms aggregates, difficult to distinguish other characteristics one clast displaying perthitic texture; large blebs of plagioclase within slightly altered potassium feldspar  fine grained matrix 35%  15  plagioclase or quartz  8  carbonate  4  muscovite  3  epidote?  3 1 1  chlorite hematite opaques  low interference colours with low relief; anhedral indistinct crystals making up majority of the groundmass variable relief and distinctive interference colours; irregular aggregates or single crystals (~0.1x0.4 mm in size), single crystals occur in irregular shapes, some are poikilitic low relief with distinct interference colours; small flakes randomly oriented throughout high relief with high interference colours; fine grained globular texture, could be mistaken for oxides at high mag green in PPL; small flakes and sprinkles present, evenly distributed reddish brown in PPL, anhedral blebs ~0.02 mm in size little black opaques, anhedral  222  T/S #  Sample #  45  27  %Modal  Mineral  Mineral Description  meta-gabbro: equigranular, idioblastic, massive, no foliation  overall slide mineralogy moderate relief and slightly pleiochroic green; forms aggregates, fibrous and randomly orientated, occasionally 35 chlorite radiating forms 30 biotite? dark brown cryptocrystalline masses variable relief with extremely high interference colours; sub15 carbonate anhedral blocks or irregular patches (~0.75-1 mm) plagioclase or finer grained patches within the serp/chlo aggregates; sizes 10 quartz range (<0.05-0.210 mm) colourless and bird's eye exctinction; interstitial, anhedral, 5 muscovite occasionally poikilitic with serp. (?) inclusions very high relief and bright interference colours; eusubhedral blocks or laths; smaller grains (0.0525-0.0575 4 epidote mm) very drk brown, 2-3 mm in elongate direction; forms 1 oxide irregular shapes The above mineralogy is reflective of total mineralogy in the slide. Below are descriptions of 2 different types of aggregates found, indicating distribution of the above aggregate 1  aggregate 2  90 chlorite see above description 10 carbonate see above description 10 epidote see above description Fine-grained aggregated serpentine (in random orientation) is interspersed with carbonate has replaced large (3x1 mm) euhedral prismatic grains. The ratio of serpentine to carbonate is ~9:1. Judging by the shape of the pseudomorphed grains, the original grains were most likely plagioclase, ~35%. Occasionally, the aggregates contain up to 10% microcryst qtz (?) albite (?), muscovite or talc. 100  biotite?  see above description  These aggregates are dark brown, with little heterogeneity and cryptocrystalline. This mineral could not be replacing olivine or pyroxene b/c of its anhedral/interstitial-like form. Possibly replaced biotite or hornblende, ~30%. reconstructed mineralogy This rock is inferred to be gabbro before metamorphism due to the coarse grained texture and abundance of original mafic minerals (olivine, pyroxene, biotite) and plagioclase.  223  T/S #  Sample #  46  16a  %Modal Mineral Mineral Description metamorphosed plagioclase-poor mafic subvolcanic rock : inequigranular, large euhedral crystals in a massive fine grained matrix consisting of laths and anhedral minerals  overall slide mineralogy porphyroblasts (20%) Note: These porphyroblasts are not monomineralic, but contain the following described minerals. slightly pleiochroic green with distinctive ~60/120˚ cleavage visible in some crystals' completely replaced 12 actinolite larger porphyroblasts Judging by the euhedral shape and 120˚ outer angles of the pseudomorphed crystal, I think actinolite has replaced cpx. These pseudomorphs can also contain up to 4% of serpentine, in addition to occasional laths of biotite.  1  biotite  1  carbonate  brown pleiochroic with high interference colours; euhedral lath forms (~0.2x0.1 mm), randomly onrieted within cpx and plag porphyroclasts variable relief with extremely high interference colours; anhedral crystals (~0.8x0.1 mm), present in cpx and plag oikicrysts  serpentine  low relief with 1st order interference colours with slight green pleiochroism; radiating forms in cpx and plag oikicrysts  1 groundmass (80%)  43  actinolite  20  plagioclase or quartz  9  carbonate  8  biotite  <0.5 chlorite? reconstructed mineralogy  slightly pleiochroic green, fine grained small cyrstals, subanhedral elongat crystals (~0.2x0.1 mm), randomly oriented low interference colours, difficult to see relief, but some twinning seen; anhedral crystals with oscillatory zoning, filling in spaces between other matrix minerals variable relief with extremely high interference colours; small anhedral masses (~0.2x0.1 mm) interspersed evenly in the matrix brown pleiochroic with high interference colours; euanhedral forms (~0.1x0.1 mm) randomly oriented within matrix moderal relief with weakly blue interference colours; anhedral (~0.1x0.1 mm) within the matrix, only a few grains found  No clinopyroxene in this sample remains and is completely altered into actinolite. The pyroxene's previous presence suggests a mafic dyke. Normally a rock with pyroxene and plagioclase present would be referred to as gabbro or diabase, but this sample due to the low percentage (relative to a gabbro) of former pyroxene and finer grained plagioclase present was named as a pyroxene-phyric mafic dyke. Replaced euhedral plagioclase suggests this rock was a dolerite.  224  T/S #  47  Sample #  %Modal  Mineral  Mineral Description  metamorphosed plagioclase-poor mafic subvolcanic rock: inequigranular, porphyroblastic: large euhedral crystals in a massive groundmass consisting of laths and 16b anhedral minerals porphyroblasts (15%) Note: These porphyroblasts are not monomineralic, but containa aggregates of the following described minerals. slightly pleiochroic green with distinctive ~60/120˚ cleavage visible in some crystals; completely replaced some 10 actinolite larger phenocrysts Judging by the euhedral shape and 120˚ outer angles of the pseudomorphed crystal, I think actinolite has replaced cpx. These pseudomorphs can also contain up to 4% of serpentine, in addition to occasional laths of biotite. brown pleiochroic with high interference colours; euhedral lath forms (~0.2x0.1 mm), randomly onrieted within cpx 1 biotite and plag porphyroclasts variable relief with extremely high interference colours; anhedral crystals (~0.8x0.1 mm), present in cpx and plag 1 carbonate oikicrysts  1-2  2  chlorite  plagioclase  fine grained matrix (85%) 30 actinolite  low relief with 1st order interference colours with slight green pleiochroism; radiating forms in cpx and plag oikicrysts low 1st order interference colours and biaxial with some simple twinning visible; euhedral and poikilitic (~3x5 mm), single crystals in groundmass, partially altered (~5-15%) by serpentine, or carbonate (~2-4%), or biotite (~2-4%), or any combination of those minerals. see above description  low interference colours, difficult to see relief, but some twinning seen; anhedral crystals with oscillatory zoning, 30 plagioclase filling in spaces between other matrix minerals variable relief with extremely high interference colours; small anhedral masses (~0.2x0.1 mm) interspersed evenly 10 carbonate in the matrix brown pleiochroic with high interference colours; euanhedral forms (~0.1x0.1 mm) randomly oriented within 10 boitite matrix moderal relief with weakly blue interference colours; anhedral (~0.1x0.1 mm) within the matrix, only a few <0.5 chlorite? grains found Note: This aggregate is only present in one area of the slide. It is ~3.5x2mm in size and within the finegrained matrix. No pseudomorph boundaries are seen. This aggregate could possibly be an altered phenocryst or an altered xenolith. high relief fine grained glomeration of crystals; high relief, low greyunknown yellow interference colours, no visible cleavage, straight aggregate 1 100 mineral extinction with no pleiochroism, length slow.  225  T/S # 48  Sample # %Modal Mineral Mineral Description 10a meta-sandstone: inequigranular, hypidioblastic, replacement features observed Note: There are three components to this sample: large monomineralic porphyroblasts, mineral aggregates, and fine grained matrix. Each are described below. 20 porphyroblasts see description below 22 aggregates see description below 58 matrix see description below monomineralic porphyroblasts (20%) variable relief, extremely high interference colours, twinning and cleavage seen; poikilitic, from ~0.2x0.1 mm up to ~1.4x1.0 mm in size, eu-subhedral form, displays oscillatory extinction, can be large single rhombs or as 19.5 carbonate interlocking aggregates of several smaller ones. anhedral and irregular shaped oxides, small (~0.04 mm in 0.5 black opaque size), randomly distributed mineral aggregates aggregate 1 (10%) : ~2.0x1.0 mm in size, oval to oblong shaped low relief, green in PPL, first order grey; fine grained anhedral aggregate, no discernable shape of the original 10 serpentine mineral Because of the indiscernable shape of the original mineral that the serpentine has replaced, the only conjecture that can be made is the serpentine has replaced a mafic mineral. These aggregates can also contain up to 4% muscovite flake (~0.2 mm in length), up to 3% of fine grained plagioclase or quartz, in adidtion to the occasional crystal of carbonate. aggregate 2 (6%): ~1.0x0.5 mm, long flattened shape low relief, first order yellow and white, length slow, no low interference cleavage or pleiochroism observed; elongate crystals 5 mica? ~0.01x0.02 mm in size, randomly oriented aggregate 3 (6%): ~1.0x0.5 mm irregular shapes low relief with disctinctive interference colours; laths 5 muscovite ~0.2x0.05 mm, randomly oriented These aggregates can also contain up to 5% fine grained serpentine, the same that is described above. fine grained matrix (58%) low relief and low interference colours; fine grained, occasional patches (~0.4x0.3 mm) of larger interlocking plagioclase or crystals, appear as inclusions in most poikilitic 50 quartz porphyroblasts anhedral and irregular shaped oxides, small (~0.04 mm in 5 black opaques size), randomly distributed reconstructed mineralogy Judging by the sizes of the replaced aggregates, which are sand sized, it could be speculated the origin parent rock was sandstone.  226  T/S # 49  Sample #  %Modal Mineral Mineral Description meta-sandstone: crystalline, massive with coarser grained veins of carbonate, evidence of 10b metamorphism This sample has one linear opaque-rich feature that runs lenthwise through the slide, displaying minor folds, possibly indicating direction of strain. A coarser grained carbonate-rich vien runs subperpendicular to the oxide-rich feature and it could be construed it also displays some minor folding. This could possibly indicate strain direction as well. Their cross-cutting relationship is difficult to determine for purposes of constructing temporal evolution. overall mineralogy low relief with low interference colours; fine grained, plagioclase or anhedral, distributed across entire slide, displays oscillatory 65 quartz zoning variable relief with extremely high interference colours; larger grained in comparison to other minerals (~0.1x0.1 10 carbonate mm), anhedral, random single crystals  9  chlorite?  7  muscovite  3  black oxide  very small (~0.01 mm) needles throughout slide, mostly as single crystals, realy as glomerations, somewhat aligned:low int, high relief green in PPL, needles straight extinction low relief with high interference colours; aligned flakes in slide euhedral small (~0.05 mm, up to 0.1 mm in size) crystals with random orientation occurs as brown patches, associated with some black unidentified mineral; possibly hematite?  <1 halo reconstructed mineralogy Due to the size of particles and their compositions, this rock is a meta-sandstone. The black linear features that undulates across the thin section is a stylolite.  227  T/S #  Sample #  50  1  %Modal Mineral Mineral Description bedded meta-argillite: fine grained, bedded: 3 beds in total that are ~6-8mm in thickness with horizontal to subhoriztonal planar bedding  overall mineralogy The following minerals are those present within the thin section, regardless of distribution. Their descriptions will be presented in the subsections, of which there are 3 (one for each bed visible). plagioclase or 60 quartz see description below 15 muscovite see description below 10 carbonate see description below 10 biotite see description below 5 opaques see description below This bed (~7mm in thickness) does not display any separations of minerals (i.e. occurring in aggregates and patches). Everything is randomly mixed within the sub-horizontal Bed 1: 25% planar beds. low relief with with high interference colours; flakes 12 muscovite aligned with subhorizontal planar bedding low relief with low interference colours; very fine to fine plagioclase or grained crystals of anhedral growth, elongate in the 10 quartz direction of bedding occur as powder throughout the whole bed and is 2 black oxide concentrated in planes of the planar bedding brown pleiochroic with distinctive interference colours; 1 biotite occurs as laths in addition to hexagonal cross-sections Bed 2: 75% This bed is ~8.4 mm in thickness. There are horizontal planar beds (~0.4 mm in thickness) that are dominated by one mineral. The following are descriptions of each different kind of planar bed. All beds may contain minerals from other planar beds as well. Some cross bedding is present. distinctive interference colours; fine grained flakes aligned muscovite-rich in direction of bedding, fine grained plagioclase or quartz is 30 bed present as well disctinctive interference colours with variable relief; larger crystals (~0.1-0.2 mm), anhedral with presence of carbonate-rich plagioclase or quartz (up to 50%) of simliar sizes and 21 bed shapes low relief with low interference colours; fine grained plagioclase or crystals make up this bed, presence of muscovite and/or 20 quartz-rich bed carbonate seen brown pleiochroic with distinctive interference colours; occurs as laths and hexagonal cross-sections; occurs 3 biotite randomly oriented in all types of planar bedding occur as powder throughout the whole bed and is 1 opaques concentrated in planes of the planar bedding These beds can be distinguished by the different textures in each: Bed 1 is darker in colour, possibly due to presence of black material. In addition, Bed 1 displays steeper cross bedding compared to Bed 2. There is another layer of black material that lies within Bed 2, but because of the similar mineralogy and texture on either side of this layer I do not think it separates Bed 2 from another different bed.  228  T/S # 51  Sample #  %Modal Mineral Mineral Description contact: porphyroblastic texture with foliation, equigranular, clastic with volcanic 12 component, serpentinized flattened clasts The descriptions below are of the metamorphosed mineralogy. flattened porphyroblasts (15%) The porphyroblasts are made up of a combination of the following minerals. The replaced porphyroclasts range in size from 3x8 mm to 2x4 mm non-pleiochroic with low relief and low interference 14 chlorite colours; fine microlites randomly-slightly oriented high relief with 3rd order interference colours; accicular ~0.04 mm in length, only seen at high magnification, randomly oriented throughout porphyroblast; some grains 1 rutile with brown alteration rims fine grained matrix (85%)  40  albite or oligoclase  low interference colours with low relief, biaxial, twinning visible; fine grained and larger twinned crystals visible (~0.2 mm in length), oscillatory zoning seen  The plagioclase only displays enough twinning to determine approximate An composition, but further constraint is difficult because of the small size of the crystals. The anorthite content is either An5 or An20 , hence it is either albite or oligoclase. variable relief, distinctive cleavage and interference colours; ~0.04x0.3 mm in size, slightly elongate anhedral 35 carbonate shapes, evenly distributed high relief, fine, acicular green "sprinkles", though not as abundance as in the porphyroblasts. Interference colours 5 epidote difficult to determine 5  opaque  grey-black powder, associated with the matrix  reconstructed mineralogy The lenticular and flattened serpentinized/chloritized clasts may originally have been volcanic clasts. The presence of rutile (a titanium-rich mineral) indicates mafic presence, in addition to the secondary serpentine.  229  T/S #  Sample #  53  41-1  %Modal Mineral Mineral Description lamprophyric breccia: a hypidiomorphic groundmass containing a clast; the clast is easily observable due to its darker colour in relation to the groundmass  clast (5%) The clast (8 mm wide and continues out of field of view) is made up of the following minerals. pleiochroic army green with bird's eye extinction and high interference colours; eu-subhedral crystals and anhedral 2 biotite masses occuring in ~0.1-0.2 mm in length pleiochroic green-brown, high relief, 60/120˚ outer angles; 1 actinolite occurs as eu-subhedral crystals ~0.04-0.4 mm in length high relief with second order interference colours; small <1 epidote anhedral crystals occuring randomly within clast very high relief and low interference colours; occurs as <1 apatite anhedral crystals up to 0.2 mm in size matrix (90%)  45  biotite  30  actinolite  7  albite  5  chlorite  3  apatite  <1  chromite  pleiochroic army green with bird's eye extinction and high interference colours; eu-subhedral crystals and anhedral masses occuring in ~0.4-0.8 mm in length, occasionally occurs in aggregates with chlorite up to 1.6 mm in length pleiochroic green-brown with high interference colours; eusubhedral crystals (~0.8 mm in size) grown in patches throughout slide, distinctive 60/120˚ outer angles observed low interference colours and low relief, biaxial; anhedral crystals occasionally twinned ~0.3 mm in size green in PPL, low interference colours; randomly oriented flakes ~0.01 mm in size, occasionally occurs in aggregates with biotite up to 1.6 mm in length very high relief and low interference colours; occurs as anhedral crystals up to 0.2 mm in size occasional small opaque crystals seen with subhedral shapes ~0.08 x 0.05 mm in size  230  T/S #  Sample #  54  41  %Modal  Mineral  Mineral Description  lamprophyre with xenoliths: xenoliths only visible in outcrop and are not represented here in thin section; equigranular, hypidiomorphic, and foliated pleiochroic brown with bird's eye extinction; crystals occur as flakes and fibrous masses, ~0.2 mm in size, all crystals 40 biotite are anhedral low relief and low interference colours; occurs as interstitial 40 albite minerals, all anhedral and a minor component pleiochoic army green with extremely high relief and high interference colours (2nd order); occurs as anhedral crystals ~0.12x0.2 mm in size and evenly distributed throughout 10 epidote slide variable relief and distinctive interference colours; anhedral and blocky crystal shpes, sometimes poikilitic ~0.5x0.5 mm 8 carbonate in size  231  Appendix C: Diamond morphology  232  Detailed morphological descriptions of Wawa meta-conglomerate diamonds. Below is key to abbreviations.  Morphology/Growth Form Single Crystal? O = octahedron d- = distorted S = single crystal C = cuboid p- = polycentric P = polycrystalline C-O = cubo-octahedron f- = flattened U = Unknown D = dodecahedron e- = elongated M = macle agg = aggregate chip = <0.8 mm fragment Growth Whole vs. Sample # Size (mm) Morph. Habit Fragment Colour 101AF-1, S23241 1-1 3.25x1 D O F dark grey 1-2 1.25x1 D O W pink 1-3 101AF Red CL 1x1 p-O O W yellow 1-4 101AF Blue CL 1.25x1 p-C C W white 1-5 1101AF 1x0.75 1-6 2101AF1 1.5x0.5 1-7 2101AF2 1.5x0.5 101AL-1, S23242 1-1 2x1 1-2 0.75x0.75 1-3 1.25x0.5  Surface features complex = combination texture; can include rough and stepped textures stepped = displaying stepped growth layers frosted = describes "brushed" texture of crystal; causes opacity rough = uneven and undulatory texture  Resorp. Class  Surface features  Inclusions  Single Crystal?  1 1  ---  fibrous growth --  S S  5  stepped  --  S  5  --  --  S  O?  O  F  white  4  --  --  S  ?  O  F  white  4  --  --  S  D chip  O  F  white  4  --  --  S  O D O  O O O  W W F  white yellow white  5 1 6  ---roughresorbed? stepped -stepped rough -rough and stepped stepped stepped  1 dark ---  S S S  several dark -several dark -graphite several dark  S S S S S S  -graphite graphite  S S U  1-4 1-5 1-6 1-7 1-8 1-9  1x0.75 1x1 1.25x0.75 1x1 1x1 1.25x0.75  d-C? O? C-O O p-D D d-O?  O C-O O O O O  F F F W W W  pale yellow white white pink grey white  4 6 4 -1 2  1-10 2-1 2-2  1x0.75 1x0.5 1.25x0.75  p-C-O O O  C-O O O  W W W  brown white white  4 3 5  Notes  233  Sample # 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 3-10  Size (mm) 1.5x1 1.25x0.5 0.75x0.75 1.25x1 1.25x1 1x1 1x1 2x1.25 1x0.5 1x1 1x1 1.75x1 1.5x1 1x1 1x1 1x25x1 1.25x1 1.5x1  101AL-2, S23242 1-1 1x0.75 1-2 1.25x1 1-3 101AL, Red 1x1 1-4 2101AL1 1.5x1 1-5 2101AL2 1.25x0.5 1-6 2101AL3 2x0.5 101BF-1, S23243 1-1 1-2 1-3 1-4 1-5  1x0.75 1x1 1.25x0.5 1x0.5 1x1  Morph. f-O O p-O O O O d-O D O chip p-O M? O? D O d-C C-O p-O D D  Growth Habit O O O O O O O O O O O O O C C-O O O O  Whole vs. Fragment W F F F F F F W F W F W F W F W F F  Colour white yellow white pink white white pale yellow white white white white white white pale yellow white white white white  d-D p-O  O O  W F  O  O  f-O  Resorp. Class 6 6 5 2 4 6 1 6 6 1 1 3-4 2 3 6 3 1  Surface features -complex stepped ---complex -complex stepped -----stepped ---  Inclusions --graphite 1 dark graphite 1 dark dark 2 dark graphite graphite, dark graphite 1 dark 1 dark --graphite graphite 2 dark  Single Crystal? Notes S S S S S S S S S S S Contaminated with blue paint S S S S S S S  white white  2-3 6  -stepped  -graphite  S S  W  white  4  graphite  S  O  W  white  6  -mildly stepped  --  S  M  O  F  yellow  6  stepped  --  S  f-O/M?  O  F  yellow  6  6  --  S  p-O C p-O p-O d-C  O C O O C  F W F F F  white yellow white white pale yellow  5 1-2 6 -2-3  complex rough -complex rough  graphite -graphite graphite --  U S S U S  "Notches" observed at one end Exhibits several different shades: white, grey.  234  Sample #  Size (mm)  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  1-6 1-7  1.25x0.75 1x1  C-O C  C-O C  F W  yellow light grey  4 6  Surface features resorbed + stepped rough  C p-O p-O? d-D? f-D O  C O O O O  W F W F W  yellow white white white white  6 6 1 1-2 5  p-O? O?  O  W  pale yellow  D O M  O O O  W F F  1-8 1x1 1-9 1.25x0.75 1-10 1.5x1 2-1 1.5x0.75 2-2 1101BF 1x0.75 2-3 2101 BF1 1x1 101BL-1, S23244 1-1 1.25x0.75 1-2 1x1 1-3 2.25x0.5  Inclusions  Single Crystal?  ---  S S  rough -----  1 dark graph graphite dark, graphite 1 dark  S S S S S  6  --  --  U  white brown white  2-3 6 res  -complex -concave surfaces complex --mildly stepped stepped stepped stepped ---stepped stepped, rough ---complex, stepped --  --3 dark  S S S  --graphite graphite  S U S S  -graphite --graphite graphite graphite graphite  S S S S S S S S  -graphite -graphite  S S S S  -fibrous growth  S S  1-4 1-5 1-6 1-7  1.25x0.75 2x1 1.25x1 2x1.25  C-O ? D O-D  C-O O O O  F F F F  white pale yellow pink white  4 6 3-4 3  1-8 1-9 1-10 2-1 2-2 2-3 2-3 2-4  1x1 1x1 1.5x1.75 1.5x1 1x0.75 1.25x1.25 1x1 1x1  C-O p-O f-O p-O D M p-O p-O  O O O O O O O O  W W W W W W W W  pale yellow white white yellow white white white white  6 6 6 5 1 3-4 3-4 4  2-5 2-6 2-7 2-8  1x1 1.5x1 1.25x1 1.5x1  C-O D chip d-C D  C-O O C O  W F F W  pale yellow pale yellow pale yellow white  6 1 5 1  2-9 2-10  1x1.25 1x1  C O? ?  O O  F W  pale yellow grey  4-5 3  Notes  Void in center of (100) face that appears to be an inverted C shape.  235  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  O C O O O  W F F W F  white green pale yellow white grey  4 3 3 6 5  f-O C D  O C O  W F F  white pale yellow pink  6 5 1  p-O f-D  O O  F F  white white  5 1  f-O  O  F  white  5  Sample #  Size (mm)  3-1 3-2 3-3 3-4 3-5  1.75x1 1.25x1 1.25x0.75 1.5x1 1x1  Morph. p-O fragment C f-O f-O O fragment  3-6 3-7 3-8  1.75x1 1x1 1.25x1  3-9 1x1 3-10 1.25x0.5 101 BL-2, S23244 1-1 1.5x1  Surface features mildly stepped rough -stepped complex mildly stepped rough -stepped, nuggety --  Inclusions  Single Crystal?  graphite dark? graphite? -graphite graph  S S S S P?  graphite, 1 dark graphite, 1 dark graphite  S S S  graphite 1 dark  S S  --  S  1 dark, 1 clear graphite graphite, 1 dark  S S S  graphite ---  S S S  1-2 1-3 1-4  2x1 1.25x1 1.5x1  f-O p-O e-D  O O O  F F W  white white yellow  5 5 4  1-5 1-6 1-7  1.25x1 1.5x1 1x1  p-O p-O ?  O O ?  F W F  white white pale yellow  4-5 1-2 5  stepped mildly stepped complex -mildly stepped -complex  1-8 1101BL 1-9 2101BL1  2.25X1  D  O  W  white  1  --  --  S  1.25x1  f-O  O  W  white  6  --  --  S  C  C  W  pale yellow  5  rough  --  S  M  O  W  white  5  --  --  S  O  O  W  white  4  --  --  S  O O  O O  F F  white white  ---  -stepped  1 dark 1 dark  S? P?  1-10 101BL, Red 1x1 2-1 2101BL2 2x0.5 2-2 2101BL3 1x1 136 AF-1, S23245 1-1 1x1 1-2 1x0.75  Notes  236  Sample # 1-3  Size (mm) 0.5x1.25  Morph. D  Growth Habit O  Whole vs. Fragment W  Colour white  Resorp. Class 1  1-4  1x1  p-O  O  F  yellow  5  Surface features -mildly stepped  D  O  F  yellow  res  O? M?  O  F  white  O? M?  O  F  D  O  ? p-O C ?  O O C O  1-5 1136AF 1x1 1-6 2136AF1 1x0.5 1-7 2136AF2 1x0.5 1-8 2136AF3 1.25x1 136 AL-1, S23246 1-1 1x1 1-2 1x1 1-3 1x1 1-4 2x1  Inclusions --  Single Crystal? Notes S Large pit visible  --  S  --  1 dark  S  6  stepped  --  S  white  5  rough  --  S  F  white  3-4  --  --  S  F W W F  white white yellow white  -6 4-5 6  complex stepped rough stepped  graph ----  U S S S  1-5  1.5x1  fragment  O  F  white  1-5  1-6  1x0.5  C-O?  C-O  F  white  5  1-7  1x1  ?  ?  F  white  --  1-8 1-9 1-10 2-1  1x1 1x1 1x1 1x0.5  C O C O  C O C O  W F W F  white white pale yellow yellow  4 5 6 6  2-2 2-3 2-4 2-5 2-6  1.5x0.5 1x0.5 1x1 1.25x0.5 1.5x1  ? chip p-O M? p-C  ? O O O C  F F W F F  pale yellow pale yellow white white pale yellow  res res -res --  2-7 2-8  1.5x1 1x1  p-O C  O C  F W  white yellow  -2-3  stepped resorbed + stepped resorbed + stepped mildly stepped stepped rough complex frosted? complex -stepped -frosted? mildly stepped rough  graphite  S  graphite  S  graphite  S  -graphite ---  S S S S  graphite 1 dark ----  U S S S S  ---  S S  Diamond lost due to transferring onto slide holders.  Half of crystal resorbed, other half exhibits sharp features (possibly due to fragmented)  237  Sample # 2-9 2-10  Size (mm) 1x1 1.5x1  Morph. C D  Growth Habit C O  Whole vs. Fragment W F  Colour yellow white  Resorp. Class 6 1  3-1 3-2 3-3 3-4 3-5 3-6  1x0.5 1.5x1 1.5x1 1x0.5 1.5x1 1.5x1  M O p-O D chip D f-O  O O O O O O  W F F F F F  white white white pale yellow white yellow  6 6 5-6 1 1 res  p-O ? p-C p-O  O ? C O  F ? W W  white dark grey dark grey white  5 --res  ? C-O  O C-O  F F  white white  res --  3-7 1x1 3-8 1x1 3-9 1x1 3-10 1.25x1.25 136 AL-2, S23246 1-1 1.5x1 1-2 1x1  Surface features rough -mildly stepped -complex ---resorbed + stepped rough rough rough  Inclusions -graphite  Single Crystal? S S  -3 dark graphite -several dark --  S S S S S S  -fluid fluid graphite  S P? S P  graphite, 1 red 1 dark  U S  graphite  S  -graphite graphite --  S S S S  1-3  1.5x0.75  f-O?  O  F  white  res  1-4 1-5 1-6 1-7  1.25x1 1.5x1 1.5x1 1.5x0.5  O p-O p-O f-O  O O O O  F F F F  yellow white yellow white  4 -2 res  -stepped resorbed + stepped mildly stepped stepped ---  1-8 136 AL, Blue CL  1x1  C  C  W  green  6  rough  --  S  M  O  W  brown  6  --  --  S  p-O  O  F  white  6  stepped  --  S  O  O  F  white  6  stepped  graphite  S  p-O  O  F  pale yellow  4  stepped  graphite  S  1-9 1136AL 1.25x0.5 1-10 2136AL1 1x1 2-1 2136AL2 1x0.75 2-2 2136AL3 1.5x1 136 BF-1, S23247  Notes  Large pit at center on one face.  Crumbly texture Crumbly texture  Crumbly texture  238  Sample #  Size (mm)  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  1-1  1x1  C w/ reentrant surface  C  W  yellow  unres  O C-O  O ?  W F  white white  4 6  rough mildly stepped rough  C fragment fragment D  C O O O  W F F W  dark grey white white black  6 res unres unres  D  C-O O  W F  brown yellow  1-2 1x0.75 1-3 1x1 136 BL-1, S23248 1-1 1x1 1-2 1x1 1-3 1.5x1 1-4 1x1  C w/ irregular and reentrant growth  Inclusions  Single Crystal?  --  S  1 dark --  S S  -frosted complex --  fibrous growth --fibrous growth  S S S U  unres 1  stepped --  -graphite 1 clear, 1 graphite graphite graphite  S S  graphite graphite  U S  1-5 1-6  1x1 1.25x1.25  1-7 1-8 1-9  1x1 1.25x1.25 1.25x1.25  O -O  O O O  F F F  white white white  unres unres 5  1-10 2-1  1x1 1X1  -O-D  O O  F F  yellow white  5 3  -complex stepped complex stepped --  C O O ?  F F W F  white white white white  5 6 5 unres  -stepped p-centric complex  -1 coloured 1 large dark graphite  S S S S  C-O O  W F  white white  unres unres  complex complex  -graphite  S S  C C-O  F W  white yellow  5 unres  complex stepped  -graphite  S S  2-2 2-3 2-4 2-5  1.25x1.25 2x1.5 1x1 1.5x1  2-6 2-7  1x1 1.5x1.5  2-8 2-9  1x1 1x1  C w/ irregular and reentrant growth  -p-O -C w/ reentrant surface  p-O C w/ reentrant surface  C-O  Notes  S S S  239  Sample # 2-10 3-1 3-2 3-3 3-4  Size (mm) 1x1 1x1.5 1x1 1x1.5 2.25x1  Morph. D O chip ? p-O  Growth Habit O O ? O O  Whole vs. Fragment F F F F F  Colour white white white white yellow  Resorp. Class res unres unres 1 res  3-5  1x1  p-O  O  W  white  5  3-6  1.25x1  ?  ?  F  white  5  3-7 3-8  1.5x0.5 1x1  chip --  ? O  F F  white white  res res  O O  O O  W F  yellow white  unres 1  C-O p-O  C O  F F  white yellow  6 unres  3-9 1x1 3-10 1x1 136 BL-2, S23248 1-1 1x1 1-2 1x1 1-3 1-4 1-5  2x1 1x0.5 1.5x1  O -O  O O O  F F F  white white white  unres res unres  1-6  1x1  O  O  F  white  unres  1-7 1-8  1.5x0.5 1x1  O  C O  F F  yellow white  unres unres  1-9 1-10  1.5x1 1.5x1  O ?  O ?  F F  white white  2-1 1136BL 2-2 2136BL1 2-3 2136BL2  1x0.5  f-O  O  W  1x1  O  O  2x0.5  f-D  O  C w/ reentrant surface  Surface features -stepped ? -complex mildly stepped mildly stepped mildly stepped stepped mildly stepped --stepped complex stepped -complex frosted in sm areas  Inclusions graphite graphite graphite 1 dark --  Single Crystal? S S S? S S  1 dark  P  --  S  -graphite  S S  1 clear graphite  S S  ---  S P?  1 dark graphite graphite  U S S  Large pit seen on one surface.  graphite  S  Large pit seen on one surface.  -1 dark  S twin  unres unres  complex -mildly stepped complex  graphite graphite  S S  white  6  stepped  graphite  S  F  yellow  6  stepped  --  S  F  white  res  --  --  S  Notes  240  Sample # Size (mm) 2-4 2136BL3 1.5x1 184AF, S23249  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  Inclusions  Single Crystal?  O  O  F  white  5  stepped  --  S  1-1 1184AF 1x1 1-2 184AF, Red 1x0.5 184AL-1, S23250 1-1 1x1 1-2 1x1 1-3 1.75x1 1-4 1x1 1-5 1.25x1 1-6 1x1 1-7 1x1 1-8 1.25x0.75 1-9 3184AL1 1.25x1  O twin?  O  W  white  6  --  several dark  U  ?  ?  ?  yellow  6  complex  graphite  P?  O twin? O fragment p-O p-O O d-O d-O  O O O O O O O O  F F? F? F W F F W  pale yellow white yellow white white pale yellow brown white  6 6 6 5 6 ----  complex -complex complex stepped -complex trigonal pits  graphite graphite graphite several dark --graphite --  S S S S S U S S  O  O  F  white  6  --  1 dark, graphite  S  S  1-10 184AL, Red 1x1 184BF-1, S23251 1-1 2.25x1.25 1-2 1.5x1 1-3 2x1.5 1-4 1x1 1-5 1x0.75 1-6 1.5x1 1-7 1.5x1.5 1-8 11842BF 1x1 1-9 184BF, Red 1x1 184BL-1, S23252 1-1 1.25x1.25 1-2 1.25x0.75  C  C  F  green  6  rough  black 'lines' on one edge  D D p-O O fragment d-fragment D fragment D  O O O O O? ? O  F F W F F F W  dark grey white white brown dark grey grey white  1 -5 --2 1  -complex stepped complex complex rough --  fibrous growth graphite -1 dark, graphite fibrous growth fibrous growth 1 yellow, 1 dark  S S S S U S S  f-O  O  F  brown  6  --  --  S  O agg  O  W  white  6  --  dark  P?  severe s-O D fragment  O O  W F  white pale yellow  6 4-5  stepped --  ---  S S  Notes  Nuggety texture with 2 shades: yellow and frosted white  Yellow inclusion observed.  241  Sample #  Size (mm)  1-3  1.5x1  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  D  O  F  white  4  d-C w/ O growth along apices  Surface features complex, stepped  Inclusions  Single Crystal?  graphite-rich  S  --graphite 1 dark  S S S S  --  S  -1 dark, graphite several dark graphite graphite grahite, dark --  S S P? S S S S  -graphite, 1 dark  S S  graphite  S  d-C O agg d-D  C-O C O O  W W W F  white white white white  6 6 6 6  1x1  O fragment  O  F  white  --  1-9 1-10 2-1 2-2 2-3 2-4 2-5  1x1 1x1 1.5x0.75 1.5x1 1x1 1x1 1.25x1.25  O fragment O O agg D C p-O D  O O O O C O O  F W F F W W F  white white yellow white grey white white  5 6 -5 6 6 4  2-6 2-7  1x1 1x1  f-O d-D  O O  W F  white white  4 2  2-8  1x1  p-O  O  F  white  6  rough, stepped -complex -complex, stepped mildly stepped -complex complex rough stepped -mildly stepped -complex, stepped  f-O  O  F  pale yellow  6  complex  graphite, dark  S  O fragment  O  F  white  3  1 dark  S  O fragment  O  F  white  5  -mildly stepped  --  S  6 4 3-4 4  rough and stepped --stepped  -graphite -graphite, 1 dark  S S U S  1-4 1-5 1-6 1-7  1.5x1 1x1 1x1 1.25x0.5  1-8  2-9 1184BL 2x1 2-10 3184BL1 1x1 3-1 3184BL2 1.5x1 401AF-1, S23253 1-1 1-2 1-3 1-4  1.25x1 1.5x1 1x1 2x1  C w/ O growth at apices  D p-O p-O  C-O O O O  W F F W  white white pale yellow pale yellow  Notes  242  Sample # 1-5 1-6  Size (mm) 1x1 1.75x1  1-7 1x1 1-8 401AF, Red 1x0.75 1-9 401AF, Blue 1.25x1.25 401AL-1, S23254 1-1 2.25x1.25 1-2 1x0.5 1-3 1.25x1.25 1-4 1.5x1 1-5 1x1 1-6 1x1 1-7 1x1 1-8 2x1.5 1-9 1x1 1-10 1.25x0.75  Morph. d-C w/ O growth at apices  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  Inclusions  Single Crystal?  ---  S S  --  S  f-O  C-O O  W W  white white  6 4  d-C  C  W  pale yellow  --  rough and stepped -resorbed + stepped  D  O  F  pale yellow  6  complex  1 dark  S  e-C  C  W  green  6  rough  1 dark  S  f-O O chip O f-O O d-O p-O O D D  O O O O O O O O O O  W F W W W F F F F W  yellow white pale yellow white white pale yellow white pale yellow yellow white  4-5 4-5 4 -4 6 -6 6 6  ---frosted? -stepped --complex --  graphite --graphite --graphite several dark graphite --  S S S S? S S S S S S  fibrous growth fibrous growth graphite?  P? S S  large dark  S  graphite  S  --1 dark graphite -graphite  S S  2-1 2-2 2-3  1x1 1x1 1x1  C agg D D  C O O  W W W  black grey white  -6 6  2-4  1.25x1  O agg  O  W  green  3-4  2-5  2x1  D  O  W  white  5-6  rough rough -resorbed + stepped mildly stepped  2-6 2-7 2-8 2-9 2-10 3-1  1x1 1x1 1.25x1 1x1 1x1 1x1  f-O f-O O p-O f-O  C-O O O O O O  W W W W F W  pale yellow white white white white white  --6 4-5 6 5  rough, stepped stepped -pitted stepped --  d-C w/ O growth at apices  Notes  Small diamond growth on outer surface. Deep pit at center on one surface  S S S  243  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  C-O C O O  W F F W  pale yellow pale yellow white white  --4-5 1-2  d-O f-O  O O  W W  white white  4 6  mildly stepped ---mildly stepped --  D fragment d-O?  C-O O O  W F F  white pale yellow white  ? 5-6 5  f-O C O O fragment f-D  O C O O O  W W W F F  pale yellow green pale yellow white white  C-O  W  Sample #  Size (mm)  3-2 3-3 3-4 3-5  1x1 1x0.5 1x1 1x0.75  Morph. d-C w/ O growth at apices M fragment D fragment D  3-6 3-7  1.5x0.75 1.25x1  3-8 1.25x1 3-9 1x1 3-10 1.25x1 401AL-2, S23254 1-1 1.25x1 1-2 1x1 1-3 1x1 1-4 1.25x1 1-5 1.5x1  d-C w/ O growth at apices  Surface features  Inclusions  Single Crystal?  --graphite graphite  S twin S S  ---  S S  rough ---  -graphite --  S S S  4-5 6 5 4 2-3  stepped rough stepped stepped --  ----1 dark  S S S S S  white  --  rough  -graphite, several dark graphite graphite  S  graphite --  S S  -graphite, several dark several dark ---  S  1-6  1.25x1.25  f-C w/ O growth at edges  1-7 1-8 1-9  1.25x0.75 1.25x1.25 2x1.5  f-O O D fragment  O O O  W F F  white white white  5 6 2-3  1-10 2-1  1.25x1 1.5x0.5  flat O M fragment  O O  F F  white yellow  5 6  2-2  1x1  O fragment  O  F  white  ?  ---mildly stepped complex complex and res?  2-3 2-4 2-5 2-6  2.75x1 1x1 2x1.5 1x1  p-O d-C D D  O C O O  F F F W  white green white white  6 6 2 4-5  complex complex ---  Notes  S S S  S S S S  244  Sample # Size (mm) 2-7 14012AL 1.5x1.25 2-8 401AL, Red 1.75x1.25 401 BF-1, S23255 1-1 1-2 1-3  1x1 1x1 1.5x1  1=4 1x1 1-5 1x1 1-6 1x0.75 1-7 401BF 1.25x1 1-8 401BF, Red 1x1 3-2 184BL, Red 1x1 401BL-1, S23256 1-1 1.5x1 1-2 1x1 1-3 1x1 1-4 1.25x1.25 1-5 1.5x1 1-6 1-7  2.25x0.75 1x1  1-8 1-9 1-10 2-1 2-2 2-3  1.25x1.25 1x1 1x1 1.5x1 1x1 1.25x1  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  Inclusions  Single Crystal?  f-O  O  W  white  5  graphite, 1 clear  S  6  -stepped, rough  D  O  W  pale yellow  several dark  S  C p-D frag  C-O C O  W W F  white white pale yellow  6 3 1-2  -rough --  S S S  F F F W  white white white white  5 3 5 6  complex -stepped --  -graphite -graphite, several dark -graphite --  ? f-D p-O f-O  O O O O  O  O  F  white  6  --  --  S  O fragment  O  F  white  6  complex  graphite, 1 dark  S  p-O p-C O M O fragment  O C O O O  F W W F F  pale yellow green white white white  6 6 4 6 6  -fibrous growth graphite -1 dark  S S S S S  d-O O fragment  O O  W F  white yellow  ? 4  stepped rough ---mildly stepped --  -graphite  S S  C C O O O O  W W F W F W  green green brown white pale yellow pale yellow  6 4 5 6 6 1  rough rough stepped stepped complex --  fibrous growth fibrous growth -1 dark graphite, 1 dark --  S S S S S S  p-C w/ O growth at apices  interpenetrating Cs  C p-O O O d-D  Notes  S S S S  Interesting twinning observed: 3 interpenetrating cuboid figures.  245  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  O C O  F W F  white white white  6 6 6  O fragment d-O d-p-O d-C O d-O D fragment D  O O O C O O O O  F F F F F W F W  white white white green white white yellow green  6 5 5 5? 6 -1-2 1  C D O fragment D d-D D fragment  C O O O O O  F W F W F F  white white white white yellow pale yellow  6 1 6 3-4 4 3  stepped rough -mildly stepped complex stepped rough stepped stepped --complex, rough -stepped -hummocky --  Sample #  Size (mm)  2-4 2-5 2-6  1x1 1x1 1x1  Morph. p-O fragment C D fragment  2-7 2-8 2-9 2-10 3-1 3-2 3-3 3-4  1x0.75 1x1 1.5x1 1x1 1x1 1.5x1 1.25x1 1x1  3-5 1x1 3-6 1.75x0.75 3-7 1.5x1 3-8 1x1 3-9 1.75x1 3-10 1x1 401BL-2, S23256 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 2-1 2-2  1.25x1 1.25x1 1x1 1x1 1x1 1.25x1.25 1.25x1 1x1 1.25x1 1.75x1 1x1 1.25x0.5  C w/ O growth at edges  d-C? d-O? C O p-O D d-C d-C w/ O growth along apices  O fragment O fragment f-O chip  C-O ? C O O O C  F F F F F F W  pale yellow white pale yellow white white white pale yellow  6 6 6 6 6 6 6  rough, stepped complex rough -stepped complex rough  C-O O O O ?  W F F F F  white yellow white white white  6 5-6 6 6 5  rough, stepped complex ----  Inclusions  Single Crystal?  graphite -graphite  S S S  graphite graphite graphite graphite graphite ----  S S S S S S S S  -graphite -----  S S S S S S  -graphite -graphite -graphite --  S S S S S S S  ---graphite dark, graphite  S S S S S  Notes  Large pit seen on one surface.  246  Sample # 2-3 2-4 2-5  Size (mm) 1x1 1.5x1.5 1x1  Morph. d-C D d-D  Growth Habit C O O  Whole vs. Fragment W W W  Colour yellow white white  Resorp. Class 6 4 2  2-6 2-7 2-8 401BL, Red M-1  1x1 1x1  O fragment chip  O O?  F F  white green  6 6  Surface features rough --mildly stepped --  Inclusions -graphite graphite  Single Crystal? S S S  ---  S S  1x1  C  C  W  white  6  rough  --  S  1-2, 16387  1x0.5  p-O  O  W  white  6  complex,ste pped  --  S  1-3, 16388A  0.75x0.5  p-O  O  F  transluscent  5  1-4, 16388B  0.6x0.5  D  O  F  transluscent  1-5, 16395A  1.2x0.75  D  O  F  1-6, 16396A 1-8, 16403  1.2x0.5 1.5x1  D p-O agg  O O  2-2, 16413  1x0.5  p-O agg  2-3, 16414  1x0.5  2-4, 16416 2-5, 16417 2-7, 16419  Notes  1-1, 15439B  --  S  4  stepped doformation lamellae?  dark  S  transluscent  2  none  --  S  W W  pale yellow transluscent  1 4  ---  S S  O  W  yellow  5  resorbed stepped stepped, rough  --  S  D fragment w/ p-growth  O  F  5  stepped  --  S  1x1 0.5x0.5 1x0.75  D C D agg  O C-O O  W W F  1 6 5  resorbed -lamellae  --graphite, dark?  S S S  2-8, 16419B  0.75x0.5  fragment  O  F  white yellowbrown white white pale yellow with brown tinting  6  complex  --  S  2-9, 16419C  0.5x0.5  D  O  W  pale yellow  2  resorbed  1 dark  S  No sharp crystal faces, some pits visible  Pits visible on surface.  247  Sample #  Size (mm)  Morph.  Growth Habit  Whole vs. Fragment  Resorp. Class  Surface features  Inclusions  Single Crystal?  2-10, 16421 3-1, 16422  0.5x0.5 1.2x0.2  O D  O O  W F  4-5 1-2  -resorbed  graphite --  S S  W F  transparent pale yellow opaque white white  16424 16429A  1.8x1.8 0.8x0.5  C O fragment  C O  6 6  rough fractured  S S  O  W  white  5  stepped  --garnet in 2nd diamond  16429B  1x0.8  p-O  P  Second smaller diamond growth on larger diamond.  16429C 16431A 16435 16439B  0.6x0.4 0.8x0.8 0.7x0.5 2x1  C p-O d-ballas?  O C O O  F W W W  -4-5 5 5  complex resorbed stepped complex  garnet ----  S S S S  In 2 pieces, described as if whole  0.5x0.2  f-O  O  W  pale yellow green white yellow white transparent  16442 M-2  6  smooth  graphite  S  1-1, 16447A  1x0.5  C  W  pale yellow  6  rough  graphite  S  1-2, 16448  1x0.5  d-C d-fragment (resorbed)  O  F  white  3  resorbed  --  S  1-3, 16449A  1.5x1  d- C w/ O growth at apices  C-O  W  brown  5  complex, rough  --  S  1-4, 16449B 1-7, 16453  0.6x0.6 0.8x0.6  C p-O  C O  W W  pale yellow white  6 5  -garphite, dark?  S S  1-8, 16455 1-9, 16459  0.8x0.5 0.8x0.8  p-O d-fragment  O C?  F W  pale yellow pale yellow  3-4 6  rough stepped mildly stepped (from resorption) irregular  ---  S S  2-1, 16447B  0.7x0.5  d- O  O  W  green  4  dark  S  2-2, 16361 2-3, 16390  0.6x0.3 0.5x0.2  coarse agg fragment  O? ?  W F  yellow white  ? 5  resorbed stepped, rough resorbed?  ? ?  S/P S  fragment: undetermined  Colour  Notes  Pits visible on surface.  248  Sample #  Size (mm)  Morph.  Growth Habit  Whole vs. Fragment  Colour  Resorp. Class  Surface features  Inclusions  Single Crystal?  2-4, 16395B  0.6x0.1  chip  O  F  white  ?  ?  ?  S  2-5, 16427F  0.5x0.5  D  O  W  white  3  resorbed  1 dark  S  2-6, 16427G  0.1x0.1  D  O  W  yellow  1  resorbed  --  S  2-7, 16431E  0.1x0.1  C  C  W  green  6  rough  fibrous growth  S  2-8, 16431G  0.1x0.1  C-O  C-O  W  white  6  stepped  --  S  2-9, 16431F 2-10, 16432M 3-1, 6432O (letter)  0.1x0.1  D  O  W  yellow  3  resorbed  --  S  0.1x0.1  C twins  C  W  grey  6  fibrous growth  twin  0.1x0.1  O  O  W  white  5  rough mildly stepped  graphite  S  Notes  249  

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