UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Diamonds in cratonic and orogenic settings : a study of Jericho and Wawa diamonds De Stefano, Andrea 2011

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

Item Metadata

Download

Media
24-ubc_2011_spring_destefano_andrea.pdf [ 4.39MB ]
Metadata
JSON: 24-1.0053094.json
JSON-LD: 24-1.0053094-ld.json
RDF/XML (Pretty): 24-1.0053094-rdf.xml
RDF/JSON: 24-1.0053094-rdf.json
Turtle: 24-1.0053094-turtle.txt
N-Triples: 24-1.0053094-rdf-ntriples.txt
Original Record: 24-1.0053094-source.json
Full Text
24-1.0053094-fulltext.txt
Citation
24-1.0053094.ris

Full Text

Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds by  Andrea De Stefano  B.Sc., Università Degli Studi of Genoa, Italy, 2002  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in The Faculty of Graduate Studies (Geological Sciences)  THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  April 2011  © Andrea De Stefano, 2011  Abstract  Diamonds can form in a number of different ways. Physical and chemical properties of diamonds classify them as formed below cratons (xenocrystal cratonic) or in a subducting slab followed by rapid exhumation (orogenic). I studied diamonds from a cratonic (Jericho kimberlite, Nunavut) and a synorogenic (calc-alkaline lamprophyres of Wawa, Ontario) setting to reconstruct the process of diamond formation. Diamonds from these two locations have been analysed for their morphology, nitrogen content and aggregation, cathodoluminescence, composition of mineral inclusions, and stable carbon isotopes. In addition, fluorescence and stable nitrogen isotopes were studied in Wawa diamonds. Mineral inclusions in Jericho diamonds were compared with diamondiferous and non-diamondiferous eclogitic Jericho xenoliths with respect to major and trace element compositions. The majority of Jericho diamonds belong to “eclogitic” (90% of the studied samples) and “websteritic” (7%) assemblages. The Jericho diamonds differ from “eclogitic” diamonds worldwide in magnesian compositions of associated minerals and extremely light C isotopic compositions (δ13C = -24 to -41‰). We propose that metasomatism triggered by H2O fluids may have been involved in the diamond formation. The model is supported by the general similarity of mineral compositions in diamondiferous eclogites to those in diamond inclusions and to secondary magnesian garnet and clinopyroxene in recrystallized barren eclogites. The ultimate products of the metasomatism could be “websteritic” diamond assemblages sourced from magnesian eclogites. Wawa diamonds show the following features typical for a cratonic origin: 1) weakly resorbed, octahedral morphology; 2) Low N content; 3) high N aggregation state; 4) the mantle  ii  signature of carbon isotopes. Other characteristics of the Wawa diamonds suggest a subductionrelated origin, i.e. 1) the presence of peridotitic and eclogitic minerals within single diamonds in a mixed paragenesis also combining shallow and deep phases, 2) the crustal signature of nitrogen isotopes. The most viable model to explain the origin of Wawa diamonds involves early subduction of crustal carbon and nitrogen followed by the carbon-bearing mantle metasomatism and advection of the diamondiferous mantle to the shallow depth of the lamprophyre magmagenesis.  iii  Preface  Part of the research contained in this thesis has been published in Contributions to Mineralogy and Petrology in the form of the following two manuscripts: 1)  De Stefano A, Lefebvre NS, Kopylova MG (2006). Enigmatic diamonds in Archean calc-  alkaline lamprophyres of Wawa, Southern Ontario, Canada. Contributions to Mineralogy and Petrology (v. 151, pp 158-173). I am the first author and my co-authors are Nathalie S. Lefebvre and Prof. Maya G. Kopylova. Nathalie Lefebvre was responsible for field mapping as well as for the collection of some of the data, including diamond morphology and, in part, nitrogen studies. I collected all the remaining data (cathodoluminescence, fluorescence, and mineral inclusion data) and wrote the majority of the manuscript, and Dr. Maya G. Kopylova co-authored the discussion section, along with providing editorial comments throughout the preparation of the manuscript.  2)  De Stefano A, Kopylova MG, Cartigny P, Afanasiev V (2009). Diamonds and eclogites of  the Jericho kimberlite (Northern Canada). Contributions to Mineralogy and Petrology (v. 158, pp 295-315). I am the first author and my co-authors are Dr. Maya G. Kopylova, Dr. Pierre Cartigny, and Dr. Valentin Afanasiev. I was responsible for collecting all the data, with the exception of major and trace element chemical analyses of minerals from the eclogitic xenoliths of Jericho, which were done by Dr. Maya G. Kopylova. Dr. Pierre Cartigny assisted me in the collection of isotopic data. Dr. Valentin Afanasiev kindly volunteered to cut and polish a selected number of diamond samples to expose mineral inclusions and for cathodoluminescence studies. I wrote the majority of the manuscript and Dr. Maya Kopylova co-authored the discussion and conclusions sections. All authors contributed with editorial comments during the preparation of the manuscript. iv  Table of Contents Abstract ......................................................................................................................................... ii Preface.......................................................................................................................................... iv Table of contents ........................................................................................................................... v List of tables ............................................................................................................................... viii List of figures ............................................................................................................................... ix Acknowledgements ...................................................................................................................... xi Dedication .................................................................................................................................. xiii 1. Introduction ............................................................................................................................... 1 1.1 Characteristics of diamonds in cratonic and orogenic settings ............................................... 3 1.2 Diamond forming processes ................................................................................................... 4 1.2.1 Origin of diamonds in the cratonic mantle............................................................... 4 1.2.2 Origin of diamonds in the orogenic setting .............................................................. 8 1.3 Geological setting of the area of Jericho, Nunavut ............................................................... 11 1.4 Geological setting of the area of Wawa, Ontario .................................................................. 13 2. Analytical techniques .............................................................................................................. 19 2.1 Diamond morphology and colour ......................................................................................... 19 2.2 Fluorescence of diamonds..................................................................................................... 23 2.3 Cathodoluminescence of diamonds ...................................................................................... 24 2.4 Infrared spectrometry of diamonds ....................................................................................... 26 2.5 Carbon and nitrogen stable isotopes in diamonds................................................................. 30 2.6 Mineral inclusions in diamonds ............................................................................................ 31 2.6.1 The use of mineral inclusions for constraints on diamond genesis........................ 31 2.6.2 Extraction and mounting ........................................................................................ 31 2.6.3 Major element analysis .......................................................................................... 33 2.6.4 Trace element analysis ........................................................................................... 33 3. Diamonds from the Jericho kimberlite - Results .................................................................... 35 3.1 Diamond morphology and colour ......................................................................................... 35 3.1.1 Size and weight ...................................................................................................... 35 3.1.2 Crystal habits.......................................................................................................... 35 3.1.3 Resorption .............................................................................................................. 36 3.1.4 Crystal intactness and fracturing ............................................................................ 36 3.1.5 Surface features ...................................................................................................... 38 3.1.6 Body colour ............................................................................................................ 39 3.2 Cathodoluminescence and growth studies ............................................................................ 39 3.3 Nitrogen concentration and aggregation state....................................................................... 42 3.4. C isotopes ............................................................................................................................. 45 3.5 Mineral inclusions in diamonds ............................................................................................ 46 3.5.1 Garnet ..................................................................................................................... 47 3.5.2 Clinopyroxene, orthopyroxene and olivine ............................................................ 48 3.5.3 Milleritic sulphides, hematite and diamond ........................................................... 51 3.5.4 Epigenetic inclusions ............................................................................................. 53 v  3.5.5 Trace element chemistry of garnet and clinopyroxene inclusions ......................... 54 4. Origin of Jericho eclogites and Jericho diamonds .................................................................. 57 4.1 Petrography of eclogites and websterites from the Jericho kimberlite ................................. 57 4.2 Geothermobarometry and mantle stratigraphy ..................................................................... 59 4.3Major and trace element chemistry of Jericho eclogites ........................................................ 60 4.4 Partial melting and metasomatic recrystallization of Jericho eclogites ................................ 63 4.4.1 Major element chemistry of primary and secondary minerals in eclogites .......... 65 4.4.2 Trace element chemistry of primary and secondary minerals in eclogites ............ 66 4.5 Comparison of DI with minerals from diamondiferous eclogites and websterites ............... 68 4.5.1 Major element chemistry ....................................................................................... 68 4.5.2 Geothermobarometry ............................................................................................. 71 4.6 Modeling the origin of the diamondiferous eclogitic assemblage ........................................ 73 4.6.1 Partial melting and metasomatism of Jericho eclogites ......................................... 73 4.6.2 Eclogite protoliths .................................................................................................. 75 4.6.3 Metasomatic origin of Jericho diamonds ............................................................... 77 5. Diamonds from the Wawa calc-alkaline lamprophyre - Results ............................................ 82 5.1 Diamond morphology and colours........................................................................................ 82 5.1.1 Crystallographic habit ............................................................................................ 82 5.1.2 Colour and transparency ........................................................................................ 83 5.1.3 Resorption and surface features ............................................................................. 84 5.2 Diamond fluorescence .......................................................................................................... 85 5.3 Diamond cathodoluminescence ............................................................................................ 87 5.4 FTIR spectroscopy ................................................................................................................ 90 5.4.1 Nitrogen concentration and aggregation state ........................................................ 91 5.4.2 Hydrogen content in diamonds .............................................................................. 96 5.5 Stable isotopes ...................................................................................................................... 96 5.6 Mineral inclusions in diamonds ............................................................................................ 98 5.6.1 Olivine .................................................................................................................. 100 5.6.2 Clinopyroxene ...................................................................................................... 100 5.6.3 Orthopyroxene ..................................................................................................... 101 5.6.4 Sulphides .............................................................................................................. 102 5.6.5 Plagioclase ........................................................................................................... 104 6. Origin of diamonds from the Wawa calc-alkaline lamprophyre .......................................... 105 6.1 Tracing the diamond source(s)............................................................................................ 105 6.1.1 Diamond morphology .......................................................................................... 105 6.1.2 Cathodoluminescence and fluorescence .............................................................. 107 6.1.3 Nitrogen content and aggregation state ................................................................ 111 6.1.4 Residence time in the mantle ............................................................................... 112 6.1.5 Stable isotopes...................................................................................................... 113 6.1.6 Diamond paragenesis ........................................................................................... 118 6.2 Possible scenarios of diamond formation ........................................................................... 123 6.2.1 A case for cratonic origin of Wawa diamonds ..................................................... 123 6.2.2 A case for orogenic origin of Wawa diamonds.................................................... 126 vi  7. Concluding discussion .......................................................................................................... 129 7.1 Characteristics of the diamondiferous mantle..................................................................... 129 7.1.1 The cratonic setting .............................................................................................. 129 7.1.2 The orogenic setting ............................................................................................. 132 7.3 Implications of this work for diamond and mantle petrology............................................. 136 7.4 Practical applications of this research ................................................................................. 139 7.5 Limitations of methods, results, and implications .............................................................. 140 7.5 Areas for future study ......................................................................................................... 141 References ................................................................................................................................. 145 Appendix A: Characteristics of diamonds from Jericho and Wawa ......................................... 158 Appendix B: Analytical precision tables .................................................................................. 171 Appendix C: Major and trace element chemistry of garnets and clinopyroxenes in eclogitic xenoliths from the Jericho kimberlite .................................................................... 174 Appendix D: permissions of use of copyrighted material ........................................................ 182  vii  List of tables Table 2.1 Comparison of results from FITR spectra collected at UBC and IPGP ..................... 28 Table 2.2 Results from multiple spectra taken from the same diamonds .................................. 29 Table 3.1 Nitrogen content and aggregation in Jericho diamonds.............................................. 43 Table 3.2 Mineral inclusion species from Jericho diamonds ...................................................... 46 Table 3.3 Major element chemistry of garnet inclusions from Jericho diamonds ...................... 49 Table 3.4 Major element chemistry of other syngenetic inclusions from Jericho diamonds ..... 52 Table 3.5 Major element chemistry of epigenetic inclusions from Jericho diamonds ............... 53 Table 3.6 Trace element chemistry of garnet and clinopyroxene inclusions from Jericho diamonds ....................................................................................................................... 56 Table 4.1. Equilibrium temperatures of coexisting garnet-clinopyroxene pairs ......................... 73 Table 5.1 Infrared characteristics of Wawa diamonds................................................................ 92 Table 5.2 C and N isotopes in Wawa diamonds ......................................................................... 97 Table 5.3 Mineral inclusion species in Wawa diamonds ............................................................ 97 Table 5.4 Major element chemistry of inclusions in Wawa diamonds ..................................... 103 Table A1 Characteristics of Jericho diamonds ......................................................................... 159 Table A2 Characteristics of Wawa diamonds ........................................................................... 167 Table B1 Precision of EPMA of inclusions in Jericho diamonds ............................................. 172 Table B2 Precision of EPMA of inclusions in Wawa diamonds .............................................. 173 Table C1 Major element chemistry of minerals from Jericho diamondiferous eclogites ......... 175 Table C2 Major elment chemistry of primary and secondary minerals from massive and foliated Jericho eclogites ............................................................................................ 177 Table C3 Trace element chemistry of garnets and clinopyroxenes from Jericho eclogites...... 178  viii  List of figures Figure 1.1 Model of the origin of cratonic lithosphere during subduction events ........................ 5 Figure 1.2 REE patterns of garnet diamond inclusions worldwide .............................................. 6 Figure 1.3 Geological map of the study area in Wawa ............................................................... 14 Figure 1.4 Ketchum’s model of Archean crustal development in the Wawa subprovince......... 17 Figure 2.1 Morphology classification scheme of McCallum et al. (1994) ................................. 20 Figure 2.2 Diamond classification scheme based on N content and aggregation ....................... 27 Figure 3.1 Distribution of crystal habits in the Jericho diamond population.............................. 36 Figure 3.2 Optical microscope images of Jericho diamonds ...................................................... 37 Figure 3.3 Relative abundances of resorption classes in the Jericho diamond population ......... 37 Figure 3.4 Histogram showing the degree of intactness of Jericho diamonds............................ 38 Figure 3.5 Distribution of body colours in the Jericho diamond population .............................. 39 Figure 3.6 Cathodoluminescence images of Jericho diamond plates ......................................... 40 Figure 3.7 Cathodoluminescence images of Jericho diamonds collected under SEM ............... 41 Figure 3.8 FTIR spectra of Jericho diamonds ............................................................................. 42 Figure 3.9 Distribution of total N concentration in Jericho diamonds ....................................... 45 Figure 3.10 Diamond type distribution in the Jericho diamond population ............................... 45 Figure 3.11 Distribution of δ13C values in the Jericho diamond population .............................. 45 Figure 3.12 Garnet inclusions in Jericho diamonds .................................................................... 47 Figure 3.13 Garnet inclusion showing superimposed octahedral morphology........................... 48 Figure 3.14 Clinopyroxene inclusions in Jericho diamond ........................................................ 51 Figure 3.15 TiO2 vs FeO plot of phlogopite diamond inclusions .............................................. 54 Figure 3.16 Image of epigenetic phlogopite inclusions from Jericho diamonds ........................ 54 Figure 3.17 REE patterns of clinopyroxene and garnet inclusions from Jericho diamonds ....... 55 Figure 4.1 Photomicrographs of foliated and massive eclogites from Jericho ........................... 57 Figure 4.2 Photomicrograph showing megacrystalline texture in a Jericho websterite ............. 58 Figure 4.3 Equilibrium temperatures of Jericho eclogites and websterites ................................ 59 Figure 4.4 mantle stratigraphic column at Jericho based on peridotitic P-T arrays ................... 60 Figure 4.6 REE patterns of garnets and clinopyroxenes from Jericho eclogites ........................ 61 Figure 4.7 REE patterns comparing Jericho eclogites and diamond inclusions ......................... 62 Figure 4.8 SEM photomicrographs of secondary clinopyroxene and garnet.............................. 64 Figure 4.9 Major element plots of primary and secondary garnets in eclogites ......................... 65 Figure 4.10 Trace elements of clinopyroxenes and garnets in diamond inclusions and in eclogites ........................................................................................................ 67 Figure 4.11 CaO vs. MgO plot of garnets in diamond inclusions and in eclogites .................... 68 Figure 4.12 Cr2O3 vs. TiO2 plot of garnets in diamond inclusions ............................................. 69 Figure 4.13 Ternary Ca-Mg-Fe diagram of garnet diamond inclusions from Jericho and from other locations worldwide ........................................................................ 69 Figure 4.14 Major element plots of Jericho diamond inclusions and Jericho eclogites ............. 70 Figure 4.15 P-T equilibrium of Jericho diamondiferous parageneses ........................................ 72 Figure 5.1 Image of crystal habits of Wawa diamonds .............................................................. 83 Figure 5.2 Distribution of morphologies and resorption in the Wawa diamond population ...... 84 Figure 5.3 Fluorescence images of Wawa diamonds.................................................................. 86 Figure 5.5 Cathodoluminescence colours in the Wawa diamond population ............................. 87 Figure 5.6 Cathodoluminscence images of Wawa diamonds ..................................................... 88 ix  Figure 5.7 Cathodoluminscence spectra of Wawa diamonds ..................................................... 89 Figure 5.8 Nitrogen concentrations in Wawa diamonds ............................................................. 90 Figure 5.9 Distribution of diamond types in the Wawa diamond population............................. 91 Figure 5.10 Relative abundances of diamond types in distinct sampling locations at Wawa .... 91 Figure 5.11 N concentrations, abundance of B centers and regularity of Wawa diamonds ....... 95 Figure 5.12 SEM photomicrographs of Wawa diamond inclusions ........................................... 99 Figure 5.13 EDX spectrum of a plagioclase diamond inclusions ............................................. 104 Figure 6.1 δ13C vs. δ15N plot of Wawa diamonds..................................................................... 113 Figure 6.2 Histograms of N isotopic composition of diamonds from Wawa and worldwide .. 114 Figure 6.3 δ13C vs. N content and δ15N vs. N content plots of Wawa diamonds ..................... 118 Figure 6.4 P-T diagram showing different thermal regimes in subduction settings ................. 120 Figure 7.1 Cartoons showing formation of Jericho diamonds in the cratonic mantle .............. 130 Figure 7.2 Cartoons showing stages of formation of Wawa diamonds in the orogenic model ......................................................................................................... 134 Figure 7.3 Cartoons showing stages of formation of Wawa diamonds in the cratonic model ............................................................................................................ 135  x  Acknowledgments  This long long journey of mine began back in 2002, when I was preparing to defend my honors thesis at the University of Genoa, in Italy. I was more stressed than I had ever been in my entire life, often repeating to myself that I was never - ever - going to put myself through something like that again. It was during those days that my thesis supervisor, Prof. Marco Scambelluri, first suggested that I should consider going for a PhD. After I graduated and the stress from my first thesis defense had waned out, I began to realize Prof. Scambelluri was not wrong, after all. A PhD would have represented a unique opportunity to go live somewhere else, expand my horizons and gain new life experiences, aside from all the knowledge and skills one accumulates while studying and doing research internationally. I have never regretted my decision and that is why I am grateful to Prof. Scambelluri for believing in me. And speaking of people who believed in me and made a difference in my life, how not to mention Prof. Maya G. Kopylova, my current supervisor. I am forever indebted with her, not only for believing in me and giving me this golden opportunity, but also for her unwavering support and willingness to share her vast knowledge, and for encouraging me to think critically, an essential requirement for doing research that graduates from Italian universities often have a hard time develop. I want to thank my committee members as well, Prof. J.K. Russell and Prof. Mati Raudsepp, for assisting me during my PhD and sharing their knowledge. I am grateful to Band-Ore Resources Ltd, to Tahera Diamond Corporation and personally to the late Hugo Dummet for providing diamond samples for my studies. I should also mention Elisabetta Pani: her help with the Scanning Electron Microscope was very valuable as was having someone to speak Italian within the Department. Grazie di tutto. My gratitude goes also to Prof. Pierre Cartigny, for welcoming me in his laboratory in Paris and for helping me in the difficult task of interpreting the isotopic data I xi  collected there. I want to thank my former employer Maureen Morrison, who allowed me to gain essential skills and experience outside of the academic field. Moreover, Maureen’s financial support allowed me to participate to the 9th International Kimberlite Conference in 2008 and I cannot state how important that was for me, academically and personally. I was also lucky to meet and work alongside with outstanding lab mates, here in Vancouver. The list is quite long, since I have been around so many years: Pat Hayman, Nathalie Lefebvre, Trevor Mogg, Goran Markovic, Bram Van Straaten, Wren Bruce, Evan Smith, Christine Miller, and Yvette Beausoleil. Thank you all for being great lab mates (and for putting up with me). My family and friends, those in Europe as well as the ones here in North America, have always been there for me over these years and certainly deserve to be mentioned among the ones who helped make this possible.  xii  To my parents: Carla (Dialma) Ottazzi and Francesco De Stefano. For the constant love and support you have given me since I was born. You are and always will be my role models.  xiii  1. Introduction Diamonds can be formed through different processes and in various tectonic settings. The study of diamonds, their mineral inclusions, and their host rocks, aside from providing pivotal information for the localization and evaluation of economic resources, is essential to investigate the characteristics of the earth’s mantle where diamonds are formed and the geological processes which take place within it. Mantle xenoliths and diamonds are the only direct samples of the cratonic mantle petrologists have access to (Meyer, 1987; Pearson et al., 2003). While xenoliths have a high chance of being contaminated by interaction with the host magma, diamonds, due to their chemical inertness, tend to preserve the characteristics of minerals and fluids that were encapsulated within them during crystallization (e.g. Meyer, 1987). For this reason, every inclusion-bearing diamond we analyze can be viewed as a snapshot of the mantle at the time of diamond formation. Diamonds are most commonly found in a cratonic setting, where they are brought up to surface by kimberlitic or lamproitic magmas as xenocrysts. Some microdiamonds found in these types of rocks are believed to be phenocrysts grown from the kimberlite magma (e.g. Haggerty 1986). Diamonds are also found in orogenic settings, either in metamorphic UHP (ultra-high pressure) rocks that underwent rapid exhumation from a subduction zone (Sobolev and Shatsky, 1990; Dobrzhinetskaya et al., 1995; 2003) or in subduction related melts that brought them to surface (Capdevila et al., 1999; Barron et al., 2008). Finally, in some rare cases (such as the Popigai structure in Siberia), diamonds are known to originate from meteoritic impact, through shock metamorphism of C-bearing country rocks (Masayitis et al., 1979). Only diamonds formed in cratonic and orogenic settings will be discussed in this dissertation.  1  Based on the chemistry of their syngenetic mineral inclusions, diamonds can be ascribed to either the peridotitic paragenesis (P-type diamonds) or the eclogitic paragenesis (E-type diamonds). It is not uncommon to find both parageneses represented within the same diamond suite brought up by a kimberlite. Diamonds have also been ascribed to the “websteritic” paragenesis (e.g. Deines et al., 1993), on account of the fact that their mineral inclusions had a composition intermediate between peridotitic and eclogitic (Stachel and Harris, 2008). Finally, diamonds containing syngenetic ultra-deep phases, such as ferropericlase and MgSiO3-perovskite (the latter reverted to a (Mg,Fe)SiO3 pyroxene structure, e.g. Hayman et al., 2005), are believed to have originated in the lower mantle and, as such, are ascribed to a distinct paragenesis. While it is a rather universally accepted paradigm that P-type diamonds are formed through mantle metasomatism (Stachel et al., 1998; 2004a; Pearson et al., 2003; Stachel and Harris, 2008), the origin of E-type diamonds and “websteritic” diamonds is still a matter of debate, especially for what concerns the role of subduction in the formation of eclogites and diamonds in the mantle and the source(s) of carbon (Jacob, 2004 and references therein; Cartigny, 2005 and references therein). Diamonds occurring in orogenic settings are rare and, due to their small size and poor quality, they are not considered suitable for commercial exploitation (Bulanova, 1995). For that reason, these diamonds have not been studied as thoroughly as cratonic diamonds have, and outstanding gaps in the scientific knowledge still exist regarding their origin, their parageneses, the source of carbon, and the exhumation processes that brought them to surface. The aim of the research in this dissertation is to address some of the gaps in knowledge concerning the diamond-forming processes and the characteristics of the diamondiferous mantle in cratonic and orogenic settings. In order to do that, two Canadian diamond suites have been  2  studied, one recovered from the Jericho kimberlite, in the northern Slave craton (Nunavut) (Chapters 3 and 4), and the other from the calk-alkaline lamprophyres of Wawa, in the southern Superior craton (Ontario) (Chapters 5 and 6). Diamonds from both locations have been studied for their morphology, cathodoluminscence, nitrogen content and aggregation state of nitrogen defects, carbon stable isotopes, and mineral inclusion chemistry. Mineral inclusions in diamonds from Jericho have been analysed for both major and trace elements, and the results compared with the chemistry of barren and diamondiferous eclogitic xenoliths from the Jericho kimberlite. Stable isotope studies on diamonds from Wawa included both carbon and nitrogen isotopes. All analytical techniques used in this project are illustrated in detail in Chapter 2. The data obtained with these techniques were used to constrain models that describe how, where and when these diamonds were formed, and how they were brought up to surface.  1.1 Characteristics of diamonds in cratonic and orogenic settings Cratonic diamonds are the most common, and are found in kimberlites and lamproites on all continents. Crystal morphology is octahedral, cubic, and cubo-octahedral single crystals and aggregates (Gurney 1989; Harris 1992).These diamonds characteristically display varying degrees of resorption from sharp edges to rounded faces, and a multitude of different types of surface textures (Robinson 1979, Robinson et al., 1989; McCallum et al. 1994). More than 99% of the diamonds have N contents below 3500 ppm (average ~200 ppm), with 99.9% N being highly aggregated (Type IaA - IaB; Cartigny et al. 2004). Orogenic diamonds are found in eclogites, pyroxenites, peridotites and gneisses from ultrahigh-pressure (UHP) metamorphic terranes (Sobolev and Schatsky 1990; Cartigny et al. 2001) or in subduction-related volcanics. The diamonds are brought to the surface by tectonic  3  uplift, such as has been observed in Morocco, Tibet, Kazakhstan, China, Western Norway, and Germany (Chopin 2003), or by magmas sampling a subducting slab, for example in New South Wales (Taylor et al. 1990) and French Guiana (Capdevila et al. 1999). Orogenic diamonds are characterized by their small size and may be replaced by graphite (De Corte et al. 1999; Cartigny et al. 2001). Their dominant morphology is cubic, cubo-octahedra and octahedral single crystals (De Corte et al. 1999; Cartigny et al. 2001); aggregates are uncommon. Skeletal and re-entrant crystals, which may be present, are diagnostic of an orogenic origin (De Corte et al. 1999) Orogenic diamonds rarely exhibit surface textures indicative of dissolution, and never show resorbed faces or experience non-uniform resorption (De Corte et al. 1999). High nitrogen contents (580-4488 ppm) and low aggregation states (Ib-IaA; De Corte et al. 1999; Finnie et al. 1994; Dobrzhinetskaya et al. 1995; Cartigny et al. 2004) are also characteristic of orogenic diamond populations. These values reflect their short residence time and/or low temperatures in the mantle (De Corte et al. 1999; Cartigny et al. 2001), which can be as low as 885-940o C for mantle residence times of 5 Ma (De Corte et al. 1999). Subduction diamonds in UHP terranes are commonly associated with plagioclase, like those in China and Germany (Shertl and Okay 1994; Stockhert et al. 2001).  1.2 Diamond forming processes 1.2.1 Origin of diamonds in the cratonic mantle The origin of diamonds in the mantle underneath cratons is strictly correlated with the origin of the thick, cold lithosphere that is found in these areas. Based on the major and trace element chemistry of diamond inclusions and xenoliths (Stachel and Harris, 1998; Stachel and Harris, 2008), as well as on experimental data (Walter, 1999), the protolith for both peridotitic and  4  eclogitic diamondiferous rocks in the cratonic mantle has been identified in highly depleted lithosphere formed at low pressure at the Archean equivalents of mid-ocean ridges, back-arc spreading centers or island arcs, where significant partial Fig. 1.1. Schematic imbrication model depicting the origin of cratonic lithosphere during Archean subduction events. Drawing has been modified from Helmstaedt and Schulze (1989) to accommodate simultaneous imbrication of buoyant, harzburgitic– dunitic oceanic lithospheric mantle (pink-lilac) and overlying basaltic–picritic crust (orange). Reproduced from Stachel and Harris, 2008.  melting and melt extraction would occur (Stachel and Harris, 2008). In the model proposed by Helmstaedt  and Schulze (1999), this suboceanic, depleted lithosphere is overridden by continental lithosphere in Archean subduction zones and subducted slabs would subsequently get sheared and imbricated in the upper subcontinental mantle (Fig. 1.1). Such process of shearing and imbrication is justified with fast ocean spreading rates (and subduction rates) inferred in the Archean, causing the subduction of hot, buoyant suboceanic lithosphere (Helmstaedt and Schulze, 1999). Radiometric dating of diamond inclusions from Africa, Australia and Siberia has shown that the formation of diamonds in the harzburgitic paragenesis (~3200÷2000 Ma) often predates the formation of those in the lherzolitic and eclogitic (~1700÷900 Ma) parageneses (Pearson et al., 1999; Stachel and Harris, 2008 and references therein). Harzburgitic garnet inclusions show “sinusoidal” REE patterns (Fig. 1.2A) which led several authors to associate the origin of harzburgitic diamonds with episodes of mantle metasomatism and melt extraction (Stachel and Harris, 1998; Pearson et al., 2002; Stachel et al., 2004 and references therein). On the other hand,  5  Fig. 1.2. Chondrite-normalized REE patterns of garnet diamond inclusions from worldwide sources. A. Harburgitic diamonds. B. Lherozlitic diamonds. C. Eclogitic diamonds. Average compositions are indicated with thick shaded lines. Reproduced from Stachel et al., 2004.  6  lherzolitic garnet inclusions in diamonds show more “normal” REE patterns, characterized by “flat” MREE and HREE (Fig. 1.2B). However, similarly to all peridotitic garnets found in diamonds, lherzolitic garnet inclusions show depletion trends in their major elements. This fact, combined with the aforementioned ages from radiometric dating, excludes the possibility that such “fertile” REE patterns are a primary feature. Stachel et al. (2004) proposed that the evolution of REE patterns in garnets, from “sinusoidal” (Fig. 1.2A) to “normal” (or “fertile”) (Fig. 1.2B) is the result of a metasomatic re-enrichment, possibly a gradual transition from fluid to melt-dominated metasomatism. The origin of the eclogitic source of diamond underneath cratons is controversial. While the vast majority of both barren and diamondiferous cratonic eclogites are can be related to the subduction of oceanic lithosphere (Jacob, 2004 for review), in a few locations (e.g. Bobbejaan and Roberts Victor kimberlites, South Africa, Caporuscio and Smyth, 1990) their compositions seems compatible with an origin as primary picritic cumulates. Furthermore, Ireland et al. (1994) showed that the trace element composition of eclogitic diamond inclusions is complementary to the one of Archean TTG (Tonalite-Trondhjemite-Granodiorite) complexes commonly found in cratons, suggesting that cratonic eclogites might be the result of partial melting during subduction. Taylor et al. (1996a) added to that hypothesis by suggesting that partial melting may have occurred after the eclogites’ emplacement in the subcratonic mantle. Stachel et al. (2004) in their review confirmed that “normal” REE patterns observed in eclogitic diamond inclusions (Fig1.2C) is compatible both with a mafic oceanic protolith and, due to their LREE depletion with respect to MORB compositions, with melt extraction. Shirey et al. (2004), based on the evidence from diamond inclusions, mantle xenoliths, isotopic dating, and seismic profiles have justified the occurrence of mainly eclogitic diamond suites on the edge of the Kaapvaal craton  7  where the post-Archean subduction caused the formation of eclogites, partial melting and metasomatism. Similar occurrences of eclogitic diamond suites on the edge of cratonic areas have been reported in Australia (at Argyle and Ellendale, Jacques et al., 1989), South America (at Guaniamo, Kaminsy 2000; Schulze et al., 2006) and Canada (at Buffalo Hills, Banas et al., 2007). Websteritic diamonds are rare and documented mostly in studies on kimberlites from Southern Africa (Aulbach et al., 2002; Deines et al., 1993; Gurney, 1984). While Deines et al. (1993) attributed their origin to mantle heterogeneity based on their C and N isotopic compositions, Aulbach et al (2002) favoured a model where melts derived from a subducted slab interact with the surrounding subcratonic peridotitic mantle.  1.2.2 Origin of diamonds in orogenic settings Diamonds are found in orogenic settings at the margin of cratonic areas, often in association with greenstone belts complexes (e.g. Lefebvre, 2004; Stachel et al., 2006) and UHP (Ultra High Pressure) rock massifs (e.g. Dobrzhinetskaya et al. 1995, 2001b; De Corte et al., 1999). As mentioned in section 1.1, these diamond occurrences are rare and considerably smaller in size, compared to those found in kimberlites and lamproites in cratonic settings. Consequentially, the database available from literature is limited and comprehensive studies including major and trace element chemistry of mineral inclusions and their geochronology have not yet been possible. In UHP massifs, diamonds are associated with metamorphic rocks of crustal origin, which underwent fast subduction to depths >120 Km. Diamondiferous lithologies in these tectonic settings reported in literature include eclogite, garnet pyroxenite, jadeitite, (Xu et al., 1992) picrites (Sobolev and Shatsky, 1990), felsic gneiss (Sobolev and Shatsky, 1990; Dobrzhinetskaya  8  et al., 1995, 2003; Massonne, 1999), metapelite (Mposkos and Kostopulos, 2001), talc schist (Bailey, 1999) and jadeite quartzite (Parkinson and Katayama, 1999). The most widely accepted model on the origin of these diamondiferous rocks is the one proposed by Sobolev and Shatsky (1990) for the UHP complex of Kotchetav, in northern Kazakhstan. According to this model, carbon-bearing crustal rocks are subducted to depths over 150 Km and undergo UHP metamorphism resulting in the crystallization of phases such as diamond and coesite. Such rocks are subsequently brought back to surface by an exhumation process fast enough to preserve the UHP mineral assemblage from thermal re-equilibration. Rubatto and Herman (2001) have demonstrated how the exhumation rates of UHP massifs can be as fast as the subduction rates. The best example of diamonds brought up by magmas that possibly sampled a subducted slab is represented by the diamondiferous komatiites of Dachine, French Guyana (Capdevila et al, 1999; McCandless et al., 1999; Cartigny et al., 2010). Diamonds found in these rocks present unusual characteristics such as a high occurrence of cubic and cuboctahedral morphologies (33%), poorly aggregated N defects (only Ib-IaA diamonds, from 2 to 76% of N-pairs), and 13C depletion (δ13C ranging from -32.6 to +0.15‰, mode at ~-27‰) (Capdevila et al, 1999; McCandless et al., 1999; Cartigny et al., 2010). The origin of this suite has been a matter of debate for over a decade. The model proposed by Capdevila suggests that diamonds were formed through subduction at depths > 150 km and later entrained by komatiitic magmas that originated as deep as 250 km. The interpretation provided by McCandless et al. (1999) is in agreement with Capdevila et al. (1999) regarding the exhumation of Dachine diamonds. McCandless et al. favour a cratonic origin of diamonds based on the similar morphology between Dachine diamonds and cratonic diamonds commonly found in kimberlites. Cartigny et al. (2010) in a recent study proposed a new model to explain the origin of diamonds found in the komatiites of Dachine. The  9  objection raised by Cartigny et al. to the subduction model of Capdevila et al. (1999) is that if diamonds originate from sedimentary carbon recycled in the mantle through subduction, then both organic and inorganic C isotopic signatures should be recognized in diamonds, as marine sediments in subduction zones are both organic and inorganic in nature. Dachine diamonds display δ13C values similar to those of organic sediments (~ -25‰), yet no diamond from this suite shows δ13C values around 0‰, as seen in inorganic marine sediments. Moreover, Cartigny et al. pointed out that N contents of Dachine diamonds (<500 ppm) are considerably lower than the contents of metamorphic diamonds found in UHP terranes (> 1000 ppm),which makes them more similar to cratonic diamonds in that respect. The alternative model proposed by Cartigny et al. claims that Dachine diamonds were formed from a carbon reservoir depleted in 13C located in the transition zone (at depths ranging between 330 and 600 km). The deep origin of the host komatiites (e.g. Arndt et al., 1998) would be compatible with entrainment of diamonds at high depths. Alluvial diamonds found at Copeton, in the Bingara district (Australia) have also been interpreted as subduction-related diamonds brought to surface by post-subduction alkali basalts that sampled a UHP complex (Barron et al., 2008). The authors based this conclusion on the following evidence: 1) the PT arrays obtained from diamond inclusion pairs, which overlap the PT conditions for UHP complexes calculated by Chopin (2003); 2) heavy often positive δ 13C values (0 ÷ +3‰), indicating that these diamonds may have formed from inorganic crustal sediments recycled through subduction (Cartigny, 1998); 3) Extensive post-tectonic alkali basaltic intrusions across the Bingara district intersect at depth a Carboniferous/Mesozoic diamondiferous eclogite-dominated UHP terrane; 4) high (> 1000 ppm) N contents, similar to those of metamorphic diamonds.  10  1.3 Geological setting of the area of Jericho, Nunavut The Jericho kimberlite (111o28.90' W, 65o59.19' N) is situated ~ 150 km north of the Lac de Gras kimberlite field and was emplaced in Archean granitoids (Contwoyto batholith, 2.58-2.59 Ga, van Breeman et al. 1989) of the Slave craton. The Jericho kimberlite is a part of a mid Jurassic (173.1±1.3 Ma, Heaman et al. 2006) kimberlite cluster, which includes 6 other kimberlite pipes and dykes. The petrography, geochemistry and emplacement history of the kimberlite have been characterized most recently by Kopylova and Hayman (2008). Mantle xenoliths found within the Jericho kimberlite are up to 30 cm in diameter and include eclogite, coarse and deformed peridotite, megacrystalline websterite and ilmenite-garnet wehrlite (Kopylova et al. 1999b). The xenoliths constrain the mantle lithological column from 40 to 220 km depths. The upper (40-160 km) lithospheric part of the column consists of coarse, texturally equilibrated peridotites and eclogites. The lower part of the column (>160 km) has been altered by asthenospheric melts and contains websterites and deformed peridotites with young, unequilibrated textures (Kopylova et al. 1999b). Eclogites comprise 25% of the mantle xenolith population of the Jericho kimberlite. They are composed of primary pyrope and omphacite, with occasional olivine, orthopyroxene, and kyanite. Petrographic observations proved the existence of two groups of eclogites, massive and foliated, with distinct mineral chemistry and fabric (Kopylova et al. 1999a). Foliated texture is partly controlled by preferential replacement of garnet and clinopyroxene by secondary volatilerich phases along specific planes. Clinopyroxene in foliated eclogite has higher contents of jadeite and hedenbergite; garnet has higher grossular content (Kopylova et al. 1999a). By mineral chemistry, the massive eclogites match Groups A and B of Coleman (1965), whereas foliated eclogite belong to Groups B and C (Kopylova et al. 1999a). Only the massive eclogite  11  with Mg-rich garnet and jadeite-poor clinopyroxene is known to contain diamond (Cookenboo et al. 1998; Kopylova et al. 1999a; Heaman et al. 2006). Worldwide, most other diamondiferous eclogites are less magnesian than the corresponding Jericho rocks (Heaman et al. 2006). Complex history of Jericho eclogites is recorded in their mantle metasomatic mineral assemblages and in multiple formation ages. The metasomatic assemblage includes amphibole, phlogopite, rutile, zircon, apatite and ilmenite (Kopylova et al. 2004). These minerals developed mostly in foliated eclogites. Zircon bearing eclogites characterized by high Na and low Mg contents and similar in mineral chemistry to foliated eclogites, have been dated (Heaman et al. 2006) and yielded a range of ages reflecting different metamorphic and metasomatic events. Hf model ages of foliated zircon eclogites of subduction origin record a generation of an oceanic crust between 2.0 and 2.1 Ga (Schmidberger et al. 2005). The oldest event of mantle metasomatism occurred simultaneously with metamorphism at ~1.8 Ga and formed zircon and rutile. Finally, the second episode of metasomatism occurred in the period 1.0-1.3 Ga and caused apatite growth and light rare earth element enrichment (Heaman et al. 2006). Zircon-bearing foliated eclogites were interpreted as metasomatised pieces of the oceanic crust possibly linked to easterly subduction off the western margin of the Slave craton and formation of the Great Bear magmatic arc 1.88- 1.84 Ga ago (Heaman et al. 2006). Ages of the diamondiferous eclogites are not known and may well be different from the above ages of foliated zircon eclogites.  12  1.4 Geological Setting of the area of Wawa, Ontario Detailed mapping of an ~80 km2 area near Wawa (Fig. 1.3) revealed that diamonds are hosted in two main types of volcanic rocks: polymict volcaniclastic breccia (PVB) and lamprophyre metamorphosed to greenshist facies. The studied diamonds were extracted from a 160 kg bulk sample of PVB, collected from trenches E (Fig. 1.3) on the Band-Ore Resources property, 20 km north of Wawa, Ontario. The following description of the Wawa PVB diamondiferous rocks is a synoptic overview of detailed petrographic and geochemical descriptions provided in Lefebvre et al. (2005). The breccia occurs as thick, 60-110 m conformable beds, traceable along-strike in intermittent outcrop for more than 4 km, whereas the younger lamprophyre occurs as 0.5-3 m dykes. Detailed mineralogical and petrographic observations indicate that the magmatic predecessors for the metavolcanic rocks are calc-alkaline lamprophyres. The breccias are interpreted as volcaniclastic rocks deposited as lahars, on the basis of observable stratigraphy within PVB, a wide range in clast lithologies, poor sorting, and paucity of sedimentary structures. Drilling results indicate that beds of breccia occur at several stratigraphic levels. Diamonds studied in this work were found in breccias that are ~200 m higher in the stratigraphic sequence (Fig. 1.3), and are therefore younger than the 2724 ± 24 Ma Cristal breccias (Stachel et al. 2004). Other breccia beds in the area are dated at 2687-2680 ± 1 Ma (Ayers, unpublished data). The Wawa lamprophyric magmas formed contemporaneously with felsic to mafic volcanic rocks and late orogenic intrusives of magmatic Cycle 3 of the Michipicoten greenstone belt (MGB), coeval with the Kenoran orogeny. All three MGB volcanic cycles, dated at 2.89 Ga, 2.75 Ga and 2.70 Ga (Turek et al. 1992), are bimodal basalt-rhyolite suites; the 2.89 Ga volcanic  13  Fig. 1.3. Geological map of the study area in Wawa, with sampling and drill hole locations. UTM coordinates are in NAD27. Open squares are locations of bulk samples from where the studied diamonds are extracted: E1, E2 - breccia of Engagement zone (this study), Cristal breccia dated by U-Pb method (Stachel et al. 2004); 3 - Mumm breccia dated by UPb method (Ayers, unpublished data). The inset illustrates a location of the Wawa subpropvince within the Michipicoten greenstone belt in the Superior craton. Dashed lines divide subprovinces of the Superior craton (Card and Ciesielski 1986). A star shows location of the shoshonitic diamondiferous lamprophyres (Wyman and Kerrich 1993; Williams, 2003) within the Abitibi subprovince and dots - locations of calc-alkaline lamprophyres within the Uchi and Wabigoon subprovinces (Wyman and Kerrich 1989).  14  units also contain komatiites (Sage et al. 1996). The third cycle of volcanism is represented by massive and pillowed, intermediate to mafic, tholeiitic lava flows, conformably overlain by intermediate to felsic tuff, breccia and clastic sedimentary rocks (Williams et al. 1991; Sage 1994). Intrusive rocks generated by this cycle of magmatism include gabbro to quartz-diorite sills and dykes (Sage 1994) and syenites (Stott et al. 2002). MGB was strongly deformed by the Wawan phase of the Kenoran orogeny (ca. 2.67 Ga; Stott 1997), which began with large-scale recumbent folding and thrusting, followed by upright folding and high-angle reverse faulting (Arias and Helmstaedt 1990; McGill 1992). A four-stage deformational history has been recognized by Arias (1990); diamondiferous PVB's are deformed by D2 and D4 events. Syn- and post-Kenoran magmatism of MGB includes lamprophyre dyke intrusions at 2.7-2.67 Ga (Stott et al. 2002) and granite intrusions at 2.65-2.63 Ga Ma (Percival and West 1994). Calc-alkaline lamprophyre dyke emplacement at 2.7-2.67 Ga was concurrent over a large area of the Superior Craton (Barrie 1990; Stern and Hanson 1992), including the Abitibi Greenstone Belt (Wyman and Kerrich 1993; Wyman and Kerrich 2002; Ayers et al. 2002). Some of these other lamprophyres with high Mg-numbers, apparently enriched in xenocrystal component, are diamondiferous (Williams 2002). The Superior province formed by repeated accretion of terranes as a result of subduction in a compressional margin (Hoffman 1989; Williams et al. 1992). This model is supported by seismic, structural and geological data (Calvert et al. 1995; Calvert and Ludden 1999; Thurston 2002). While the general model of subduction and accretion has been widely accepted for the Superior craton, tectonic origin of its individual terranes may vary. The MGB was originally interpreted as an autochthonous terrane, tectonically transported to its present position, detached from its original mantle "root". The volcanic rocks of Wawa were thought to have been formed  15  as assemblages of island and continental arcs (Sylvester et al. 1987), as part of the 2.7 Ga synorogenic and subduction-related magmatism (Sage 1994 and references therein). However, evidence from recent geological and geochronological studies is not consistent with the MGB as an allochthonous exotic terrane (Thurston 2002). The newer competing model which has been gaining support advocates an autochthonous origin for the MGB, with greenstones being accumulated in place, erupting through and being deposited upon older units (Thurston 2002; Ayers et al. 2002). This newer model suggests that the Superior Province experienced orderly, autochthonous progression from platforms through rifting of continental fragments, all followed by late assembly during the Kenoran orogeny. This interpretation of early cycles of Michipicoten volcanics as flood basalt provinces and intra-cratonic magmatism is supported by geochemical evidence, which records crustal geochemical signatures and significant contributions from continental passive margin sources (Sage et al. 1996). The Cycle 3 magmatism may also have a flood basalt origin (Sage et al. 1996), or may be more closely related to subduction as it is synorogenic (Sage 1994). The autochthonous model implies that MGB magmatism was rooted in the underlying lithospheric mantle, and is representative of its thermal state. A model proposed by Ketchum et al. (2008) suggests that the formation of sialic crust during the first cycle of MGB magmatism occurred between 2.92 and 2.82 Ga (Fig. 1.4), an age consistent with the measurements conducted by Moser et al. (1996) using U-Pb systematics on single grain zircons. According to these authors, the crust formed during the MGB cycle 1 underwent rifting, followed by the formation of an ocean basin and a continental margin. Volcanic rocks of MGB cycles 2 & 3 were then emplaced at 2.75-2.70 Ga both in subduction and oceanic plateau environments. The presence of inherited zircons dated at ~ 2.82 Ga in these rocks seems to point towards interaction with older crust from the first MGB cycle in proximity  16  Fig. 1.4 Schematic illustration of Archean crustal development in the vicinity of the present-day Abitibi-Wawa subprovince boundary. Top panel: Crustal development in the Wawa subprovince began at ca. 2.93 Ma with initial growth of the Michipicoten greenstone belt (MGB) and contemporaneous felsic plutonic activity. We postulate the growth of an early continental block that may have been subsequently rifted to form an east-facing (present-day coordinates) continental margin. The age of this rifting event, if it occurred, is unknown, and a mantle plume-related cause is entirely speculative. Bottom panel: Continued crustal growth in the eastern Wawa subprovince and initial crustal development of the Abitibi subprovince. This 2.75 to 2.70 Ga period witnessed comparable volcanic and plutonic activity in both subprovinces, and a variety of tectonic settings have been postulated by earlier workers. Based on new and existing isotopic data, older crust of the Wawa subprovince likely underlay the southwestern edge of the Abitibi subprovince from ca. 2.75 Ga onward and locally contributed to Abitibi crustal growth. If the Wawa continental margin was formed by rifting, inherent structural weaknesses may have remained following this period of crustal growth. AGB = Abitibi Greenstone Belt (Reproduced from Ketchum et al., 2008).  of the Wawa continental margin. Ketchum et al.’s model indicates that older sialic crust from MGB cycle 1 must have underlain MGB rocks from cycle 2 & 3 in the Wawa subprovince (Fig 1.4), a hypothesis corroborated by Lithoprobe seismic reflection profiles of the area (e.g. Percival et al., 1989; Percival and West, 1994). A recent discovery in the Wawa province have been diamondiferous conglomerates, dated at 2.68 Ga, found 12 km northeast of the town of Wawa (Ryder et al., 2008). These conglomerates are poorly sorted and polymictic, containing clasts of basalt, rhyolite, 17  gabbro, diorite, and sandstone. Diamonds are found in the matrix, mixed with typical indicator minerals of kimberlitic diamonds the likes of garnet, chrome diopside, ilmenite and spinel (Verley, 2009). Wendland (2010) performed whole rock analyses of the matrix, and indicated that it is compatible with a mafic-ultramafic source. Although there is no knowledge of kimberlites older than these conglomerates in age in the Wawa area, based on the analyses of picroilmenite clasts, Ryder et al. (2008) hypothesized that kimberlite was the original carrier for diamonds. According to Ryder et al. (2008) and Wendland (2010), the conglomerates may have formed as a proximal alluvial fan debris flow in a fan-delta environment near a diamond source rock.  18  2. Analytical techniques Diamonds from Wawa and Jericho were analyzed using standard and advanced techniques that have been applied in previous studies on diamonds from other locations worldwide. Such techniques include examination of diamond morphology under optical and scanning electron microscope, fluorescence and cathodoluminescence imaging of rough and polished diamonds, cathodoluminescence spectrometry, Fourier Transform Infrared Spectrometry (FTIR), C and N stable isotope geochemistry, and analyses of major and trace element composition of mineral inclusions. This chapter contains a review of all the above analytical techniques applied in this project and their use in the characterization of diamond.  2.1 Diamond Morphology and Colour The study of crystal morphology is considered of primary importance to discern different populations within a diamond suite (Harris et al., 1975; Robinson et al., 1979; McCallum et al., 1994; Gurney et al., 2004). Morphological observations, coupled with previous experimental work, can be crucial in reconstructing diamond history, from crystallization to the rise to the surface within the host magma. In this study, we described the morphology of diamonds from Jericho and Wawa in terms of crystal habit, resorption, intactness, surface features and body colour. The results are presented in Table A1 and A2 (Appendix A). Diamond crystallizes in the isometric (or cubic) system, hexoctahedral class, space group Fd3m(Deer, 1997). Crystal forms are the {111} octahedron and the {100} cube. Crystal habits and morphological features resulting from the competition between the two  19  forms are frequently encountered. Certain crystal habits commonly seen in diamond, such as the rhombododecahedral and the tetrahexahedral habit, are the result of resorption on a octahedral crystal and cannot be defined rigorously in terms of crystallographic forms (Robinson, 1979). Polycrystalline habits such as aggregates and twins are also commonly seen in diamond. Aggregates are defined as coalescent multiple crystals (e.g. Harris et al., 1975). A twin is defined as the symmetrical intergrowth of two or more crystals (Klein and Hurlbut, 1985). Resorption is a dissolution process occurring during the residence of the diamond in the mantle or in the host magma (e.g. McCallum et al., 1994). Resorption can significantly change the habit of diamond crystal from a sharp octahedral shape to a rounded rhombododedacahedron or tetrahexahedron (Robinson, 1979). McCallum et al. (1994) developed a classification scheme that identifies 6 different classes of resorption (Fig 2.1).  20  Crystal intactness is an expression used to describe the amount of the original crystal lost due to protomagmatic and technogenic fracturing. Fracture surfaces on a diamond crystal are interpreted as protomagmatic when they bear evidence of recrystallization or resorption postdating the fractures. Such fracture systems are believed to occur prior the eruption of the host magma (Robinson, 1979). Technogenic fractures do not bear such evidence and likely occurred during diamond extraction from the ore. The four divisions used in the classification of diamond intactness are as follows: intact, broken, fragment, and fraction (after F.V. Kaminsky, personal communication). A crystal is defined as intact when all or nearly all of its growth surfaces are preserved; as broken when it retains more than 2/3’s of its original growth surfaces; as a fragment when the amount preserved is between 1/3 and 2/3’s of the original; as a fraction when less than 1/3 of the original crystal is preserved. In many cases, especially when dealing with crystal aggregates, defining crystal intactness is challenging and rather subjective. Surface features can reveal a large amount of information pertaining to the diamond’s history of growth and resorption (e.g. Robinson, 1979). In the present study, we noted and described the following surface features: etching pits (trigons, hexagons and quadragons); etching channels; frosting; hillocks; and radioactive damage green spots. Etching pits are defined as flat bottomed pits characterized by well defined geometrical shapes (triangles, hexagons, or squares) found on the diamond’s surface (Orlov, 1977; Sunagawa, 1984). Etching channels or ruts are defined as cracks expanded by resorption or etching (Robinson, 1979). Frosting, as described by Orlov (1977), Robinson (1984) and McCandless et al. (1994), is a non transparent cover on the diamond surface derived from micrometer scale trigonal and hexagonal etching pits occurring at a  21  late stage of the etching process. Frosted surfaces are observed on cubic and/or resorbed diamonds, which often appear translucent to opaque. Hillocks are described as pyramidal and drop-shaped positive-relief features that are controlled by crystal habit but observable only on rounded faces (Orlov, 1977). Plastic deformation lines are defined by McCallum et al. (1994) as closely spaced, parallel linear features that are oriented perpendicular to the edges of the {111} octahedral faces of the crystal. Finally, radioactive damage spots are dark green or brown, roughly circular spots that appear on the diamond’s surface or inside of it, often conferring a green hue to the entire crystal. These spots are caused by damage of the crystal lattice induced by emission of α-particles from the radioactive decay of certain elements in surrounding minerals (McCallum et al, 1994). Surface features of Jericho diamonds were examined using a Philips XL-30 scanning electron microscope (Department of Earth and Ocean Sciences, University of British Columbia). The SEM was operated in back-scattered electron mode using a 15V beam current and a beam size of 6 µm. Body colour, as observed under an optical microscope on a white background, also contains a fair amount of information on a diamond suite. Colourless diamonds normally contain little or no nitrogen and are characterized by low degree of deformation. Yellow diamonds contain relatively high amounts of nitrogen defects (in the order of thousands ppm; Harris, 1987). Diamonds showing grey to dark gray colours have experienced some degrees of graphitization (Orlov, 1977; Robinson, 1979). A brown or pink body colour can be due either to internal deformation of the crystal lattice (Orlov, 1977; Robinson, 1979) and/or partial graphitization (Harris, 1987). Blue diamonds are characterized by boron substitutions in the crystal lattice (Harris, 1987).  22  Two hundred and nine diamonds from Jericho were examined under a Leica MZ FLIII optical microscope with a 10x zoom lens and 1x objective lens, both in transmitted and in reflected light mode. Digital images were collected using a Spot Insight Colour camera and edited using Adobe Photoshop 6.0 and Corel Draw 12 (Fig. 3.2).  2.2 Fluorescence of diamonds Fluorescence (FL) is an optical property of diamond often used to separate different diamond populations, as well as to distinguish diamonds from other heavy minerals extracted from mines. FL is caused by the exposure of valence electrons in the crystal lattice to an ultraviolet (UV) light. UV beams cause the valence electrons to “jump” to higher energy states. When the excited electrons fall back to their original energy state, they emit light in a certain wavelength that results in a color. The wavelength(s) of such emissions and, therefore, the FL colours observed in diamonds can be used to qualitatively determine concentrations of optical centers within the diamond crystal lattice (Fritch, 1998). Most common FL colours observed in diamond are blue and orange-yellow (Clark et al., 1992). We examined the fluorescence of diamonds from Wawa and Jericho on a Leica MZ FLIII optical microscope with a 100 watt UV bulb attached to a and powered by an EBQ Netz power source. The differences in fluorescence intensity and colour are qualitatively evaluated through photography. To compare intensities and colours, exposure times on photographic images must be constant for all samples. Images of fluorescence, when possible, were collected using a Spot Insight Colour 3.2.0 digital camera with an exposure time of 20 s (Fig. 3.6). While it was possible to collect FL images of 20 out of  23  the 80 Wawa diamonds, the FL effect of other Jericho diamonds appeared to be too weak to allow the collection of meaningful FL images.  2.3 Cathodoluminescence of diamonds Cathodoluminescence (CL) is a luminescence property induced on diamonds by exposing them to an electron beam, which excites valence electrons in optical centers to higher energy states; as these electrons fall back to their original energy state, light is emitted at certain wavelengths within the visible spectrum. The wavelengths of cathodoluminescence contain information on the diamond’s crystal lattice and its impurities (i.e. nitrogen, hydrogen, boron, etc., e.g. Paczner et al., 2000; Zaitsev, 2001). CL spectrometry is used to qualitatively detect CL wavelengths and their intensities. Cathodoluminescence imaging, especially when performed on cut and polished diamond slabs, can show zonation within the crystal that is useful to reconstruct its history of growth and resorption and, eventually, the relationship between the crystal and the mineral grains included in it. Sixty three diamonds from Wawa and 30 diamonds from Jericho were examined for their CL colour using a Cambridge Instruments Cathode Luminescence (CITL 8200 mK4) system attached to an optical microscope with a 2.5x lens. The accelerating voltage used was 15 kV with an electron beam current of 300 μA, and the chamber pressure was maintained using a Varian DS 102 pump. Diamonds were mounted in CL-inactive carbon putty and placed on a recessed steel tray specially designed to fit the chamber. The CL spectral characteristics of 20 selected diamonds from Wawa and 10 selected diamonds from Jericho were investigated using an Electron Optics Services (EOS) CL spectrometer  24  attached to a Philips XL 30 scanning electron microscope. The spectrometer was a high sensitivity 2048 charge coupled device (CCD) with selected grating optimized for 3601000 nm spectral coverage. The acceleration voltage used was 20 kV with an electron beam current of 100 μA. The CL spectra were processed using software provided by Ocean Optics Inc. and Peak Fit. Input data were first smoothed using Gaussian convolution in order to remove the noise and then deconvoluted using a Gaussian algorithm to peaks with fixed position (common CL diamond peaks such as those at 435 and 503.2 nm; Zaitsev, 2001) and other peaks with variable positions. The process was then iterated until the coefficient of determination (r2), calculated with the method of least squares, reached a value of ~0.999. The standard error in the X position of the peaks (0.22 nm) was calculated for 95% confidence limits. Ten polished diamond plates cut from Jericho diamonds were examined for their CL characteristics using a Philips XL 30 scanning electron microscope with a CL attachment consisting of a Hamamatsu R376 photomultiplier tube (Dept of Earth and Ocean Sciences, University of British Columbia, Vancouver). The accelerating voltage was 20kV and the electron beam current was 100 μA. The spectral range of the system was 300-800 nm. These 10 Jericho diamonds were sawn and polished by Dr. Valentin Afanasiev of the Institute of Geology and Mineralogy of the Syberian Branch, Russian Academy of Sciences. The direction of the cut was along {110} crystallographic plane and inclusions were exposed on the surface of the diamond plate.  25  2.4 Infrared Spectrometry of diamonds The nitrogen content and the aggregation state of nitrogen defects within a diamond can be determined using a technique known as the Fourier Transform Infrared Spectroscopy (FTIR). This technique is based on the absorption of infrared (IR) light by the atomic bonds in the crystal lattice. The wavelengths absorbed by the C-C bonds within the diamond lattice range are between 1500 and 2500 cm-1 (“two phonon” region of the spectrum). Wavelengths revealing the presence of nitrogen fall in the so called “one-phonon” region between 900 and 1333cm-1. Based on the presence or absence of nitrogen in their crystal lattice, diamonds are classified respectively as Type I (nitrogen bearing) or Type II (nitrogen free) (Robertson et al, 1934). Depending on temperature, plastic deformation, and time of residence in the mantle, nitrogen atoms can form aggregates. Nitrogen atoms initially form isolated defects by replacing C atoms, then they tend to aggregate in bonded pairs that are detected as “A” centres in an IR spectrum (Davies, 1976); nitrogen atoms can then aggregate in quartets surrounding a vacancy in the crystal lattice; such defects are detected as “B” centres in an IR spectrum (Evans and Qi, 1982). During the formation of these centers, a carbon atom needs to be displaced to make room for the four nitrogen atoms and create the vacancy. These displaced C atoms would then aggregate to form what are known as platelets (Woods, 1986). Platelets are responsible for one phonon IR-active bands known as both D centers and B’ peaks. The percentage of aggregated nitrogen defects can be determined using spectral deconvolution. Most natural diamonds are classified as Type Ia, i.e. diamonds containing aggregated nitrogen defects (Evans, 1992). Type Ib diamonds, i.e. diamonds containing  26  isolated nitrogen defects, are very rare in nature, but relatively common among artificially grown diamonds.  A further subdivision is established between Type IaA diamonds, where the majority of defects are aggregated in pairs, Type IaB diamonds, where most defects are aggregated in quartets, and the transitional (most common in nature) Type IaAB (see classification scheme in Fig. 2.3). Infrared (FTIR) spectra were obtained for a total of 54 diamonds from Jericho. Twenty-three diamonds were analyzed at the Earth and Ocean Sciences department of the University of British Columbia in Vancouver, using a Nicolet 710 FTIR spectrometer with a Nic-Plan IR microscope attachment and liquid nitrogen reservoir. Absorption spectra were measured in transmission mode in the range of 4000–650 cm-1 at a resolution of 8 cm-1 by averaging the signals of 256 scans. Thirty-five diamonds (including three diamonds previously analyzed in Vancouver) were analyzed at the Insitut de Physique du Globe of University Paris VII in Paris, France, using a Magna 560 27  FTIR spectrometer with a Nic-Plan IR microscope attachment and liquid nitrogen reservoir. Absorption spectra were measured in transmission mode in the range of 4000–650 cm-1 at a resolution of 8 cm-1 by averaging the signals of 300 scans. The rough stones were mounted using the method of Mendelssohn and Milledge (1995): the diamonds were attached to the edge of glass thin section using taut double sided tape, allowing the IR beam to penetrate freely through the diamond sample. Spectra were recorded at the point of maximum light transmission through the sample. Spectra collected on four diamonds (076G, 256X, 318G, and 363R, see section 3.3) at both locations yielded consistent results, with variations in the total N content ranging from 10% to 18%. Table 2.1 shows the results obtained on the same three diamonds from the Jericho suite (304QJK, 375G, and 395G(II)) analyzed at the UBC laboratory in Vancouver and at the IPGP laboratory in Paris. The discrepancy is within the expected analytical error (~20% of the measured ppm content, see below) both for total concentration of nitrogen and for aggregation state of nitrogen defects, showing that the results from the two labs can be treated as a single unit. Table 2.1. Results from FTIR spectra collected at UBC and IPGP on the same diamonds  sample 304QJK 375G 395G(II) 414  Ntot (ppm) UBC IPGP 51 59 697 608 606 61 49 29 43  NB (ppm) UBC IPGP 9 6 112 143 107 5 10 BDL BDL  %B UBC IPGP 18 11 16 19 15 8 20 0 0  The reproducibility of FTIR measurements was checked by collecting multiple spectra on the same spot of the same diamonds and under the same experimental 28  Table 2.2. Multiple FTIR spectra collected on the same spot and under the same experimental conditions for three different diamonds. Sample Run A(ppm) B(ppm) B% Total N Difference (ppm) (%) 1 160 65 29 225 2 3.5% 157 60 28 217 172 3 3.5% 165 68 29 233 4  157  71  31  229  1.7%  316G  1  853  671  44  1524  -  375G  2 1 2  850 608 606  672 143 107  44 19 15  1522 750 713  0.13% 4.9%  conditions. Variations ranging from 0.13 to 4.9% were observed in the total N contents after spectral deconvolution (Table 2.2). Multiple spectra (from a minimum of 2 to a maximum of 4) were also collected on different spots in 24 samples to check for possible heterogeneous distribution of N centers in the diamond lattice. Variations in the total N content range from 5% (out of a total N content of 22 ppm in sample 284X) to 20% (out of a total N content of 1433 ppm in sample 316G). The spectra were corrected for varying diamond thickness by reference to the spectrum of type II diamond with a known thickness and using the thickness correction factor of 11.94 absorption unit cm-1 (Mendelssohn and Milledge 1995). One absorption unit corresponds to the absorption value at 1995 cm-1. After baselining, spectra were manipulated using Omnic version 6.0a software and were de-convoluted into several components (C, A, B, and platelet B’) using least square techniques. C centers are single substitutional nitrogens with characteristic absorption peaks at 1130 and 1344 cm-1; they are absent in the Wawa and Jericho stones. The platelet B’ component is a peak at 1359÷1374 cm-1 caused by stretching of C–C bonds in platelets (Clark et al. 1992). 29  Nitrogen concentrations (in atomic ppm and in percentages of the total nitrogen content) were calculated on the basis of the 1282 cm-1 absorption peak using the Boyd et al. (1994, 1995) formulas for quantification of A- and B-centers, respectively. Detection limits and errors, according to Stachel and Harris (1997) and Stachel et al. (2002), are strongly dependent on the quality of the crystal face, but typically range between 10 and 20 ppm or 10–20% of the concentration, respectively.  2.5 Carbon and Nitrogen stable isotopes in diamonds The study of C and N stable isotopes in diamond is crucial for determination of sources of C and N from which the diamond originated. Furthermore, diamonds are the only mantle material for which both the C and N isotopic compositions can be determined accurately, therefore diamonds can provide important clues on the earth’s degassing history and the recycling of the major components of the earth’s atmosphere (Cartigny et al., 1998). The C isotopic composition of 51 diamonds from Wawa and 23 diamonds from Jericho was determined. The N isotopic composition was also analyzed for 13 diamonds from Wawa. The isotopic compositions were measured after combustion of pure diamond (no inclusions) in an oxygen atmosphere and a temperature of 1100 °C. The isotopic compositions are expressed as the classic delta notation (defined as δ13C=[(13C/12Csample) / (13C/12CPDB)−1]×1000 for carbon and δ15N=[(15N/14Nsample)/(15N/14Nair)-1]×1000 for nitrogen). CO2 produced by the combustion was analyzed for carbon isotopes with a conventional dual inlet gas source mass spectrometer at the Institut de Physique du Globe, University of Paris VII, Paris, France. Nitrogen was separated from carbon  30  dioxide and any nitrogen oxides reduced to N2 using a CaO/Cu mixture. Nitrogen concentrations were measured with a capacitance manometer with a precision better than 5%. Nitrogen isotopic composition was analyzed with a specially constructed triple collector static vacuum mass spectrometer directly connected to the extraction line. In addition to blank determinations, 40Ar (m/z=40) was also monitored in the mass spectrometer as an indicator of a potential atmospheric pollution for both sample and blank. The blank contribution was below 3 ng of nitrogen with δ15N of −11±3‰. The accuracy of the measurements, as established on the basis of standard analyses, is better than ±0.1‰ and ±0.5‰ (2σ) for δ13C and δ15N, respectively (Cartigny et al., 1998).  2.6 Mineral inclusions in diamonds 2.6.1 The use of mineral inclusions for constraints on diamond genesis The study of mineral inclusions is essential to determine the diamond paragenesis and thermobarometric conditions in the mantle at the time of diamond crystallization. Diamonds often contain syngenetic inclusions, i.e. minerals that were formed roughly at the same time as their host (e.g. Meyer, 1987), as opposed to epigenetic inclusions, which were formed in cracks or veins after the diamond had completed its growth. Syngenetic inclusions are recognized by euhedral crystal habit, uniform colour and uniform chemical composition. By contrast, epigenetic inclusions normally show irregular shapes, ununiform colour and variations in chemical compositions within the same grain (Meyer, 1987). Some syngenetic inclusions, e.g. sulphides and some silicates, can be dated with radiogenic isotopes to determine the age of diamonds (Richardson et al., 1984).  31  2.6.2 Extraction and mounting In order to isolate mineral inclusions from their diamond hosts and analyze their major and trace element chemistry, we used three different techniques that will be illustrated separately in the following paragraphs. The first technique was used on the Wawa diamonds, which are characterized by small sized inclusions (often <20μm). The second and third techniques were used on the diamonds from Jericho, in which mineral inclusions range in size from <20μm to >100μm. Fourteen diamonds from Wawa were crushed in an enclosed steel cracker to expose their mineral inclusions. Diamond chips with exposed inclusions were then mounted on stubs with double sided black tape and examined under SEM in backscattered electron mode (BSE). In some cases, smaller inclusions that had not been noticed under the optical microscope were found under the SEM. All inclusions were then identified using energy dispersion spectrometry (EDS). Due to the small size of inclusions and their nonhorizontal orientation on the stubs, only 7 of the 63 grains found in the Wawa diamonds could be analyzed quantitatively for their major element chemistry. Sixty-eight inclusions were extracted from 36 Jericho diamonds, using the second technique, by mechanical crushing in an enclosed steel cracker. Once isolated from the host diamond, inclusions were mounted in Miapoxy 100™ resin on transoptic stubs and polished by hand using Buhler™ polishing cloths and diamond pastes. In the third technique, twelve inclusions were exposed on 10 cut and polished diamond plates (see section 2.3). Diamond plates were then mounted on aluminum cylinders using  32  black double sticky tape to analyze the inclusions exposed on their surface with electron microprobe.  2.6.3 Major element analysis Electron probe microanalyses (EMPA) were performed on a fully automated CAMECA SX-50 microprobe at the University of British Columbia, in Vancouver. When analyzing Wawa diamond inclusions, the probe was operating in wavelength dispersion mode with the following conditions: excitation voltage of 15 kV; beam current of 20 nA; peak count time 30s; beam diameter 1 μm. When analyzing Jericho diamond inclusions, the probe was operating with the following conditions: excitation voltage 15 kV; beam current 20 μA; peak count time 10 s; beam diameter 3 μm. A variety of well characterized minerals and synthetic phases were used as standards. Minimum detection limits and accuracy of measurements are shown in Table B1 and B2 (Appendix B).  2.6.4 Trace element analysis Fifteen garnets and six clinopyroxene DI, as well as 22 grains of garnet and clinopyroxene from eclogites have been analyzed for selected rare earth elements (REE), Cr, Ni, Rb, Sr, Y, Zr, Hf, Nb, and Ba (Table 4). Trace element analyses of garnet and clinopyroxene were performed at the School of Earth and Ocean Sciences of the University of Victoria using a Thermo Electron XSII X7 ICP-MS with a New Wave UP213 laser ablation microprobe (LAM). The method was described in Chen (1999). The external calibration and method precision were determined by replicate analyses of NIST 611, NIST 613, and NIST 615 standard glass. Peak counting times vary between 5 and 15  33  s depending on the size of the analyzed inclusions. Minimum detection limits (MDL) were calculated as 3 times the standard deviation of the lowest concentration standard and vary considerably depending on the analyzed element (Table 4). Relative standard deviations (% RSD) also have a wide range depending on the concentration of the analyzed element (e.g. %RSD for Cr=2.6; %RSD for Ce=58) (Table 4). The analysis was carried out only on fresh grains from DI and eclogites, but several grains of recrystallized garnet and clinopyroxene in eclogites were analyzed for comparison.  34  3. Diamonds from the Jericho Kimberite - Results 3.1 Diamond morphology and colour The results of the morphological studies conducted on diamonds from Jericho are summarized in Table A1 (Appendix A). The following paragraphs provide a more detailed overview of the features examined under optical and scanning electron microscope.  3.1.1 Size and weight The 208 diamonds studied vary considerably in size (0.2 ÷ 5.5 mm in one direction, average of 1.6 mm) and weight (0.234 ÷ 31.172 mg, average of 2.989 mg). Diamonds were selected on the basis of content of mineral inclusions from stones < 2 mm in one direction. The size and weights of the Jericho diamonds presented here are by no means representative of the whole population.  3.1.2 Crystal habits The vast majority of Jericho diamonds (88%) are monocrystalline, while 12% are polycrystalline. Among the 12% polycrystalline diamonds, 9% were classified as aggregates, and 3% as twins. The type of twins found in the Jericho diamond population is known as macle: pairs of octahedral crystals joint by the (111) face and showing a flat, triangular shape (Harris et al., 1975) (see diamond 331X in Fig. 3.2). The predominant crystal habit encountered in the studied diamonds is the octahedral, followed by cubic, rhombododecahedral, and macle (Fig. 3.1).  35  Four per cent of the diamonds could not 3%  be classified with respect to a crystal habit  6%  4%  4%  as in these stones less than 1/3 of the volume  Octahedron Dodecahedron Macle Cube Unknown  and none of the surfaces of the original crystal are preserved. Examples of crystal 83%  habits seen in diamonds from this study are shown in Fig. 3.2.  Fig. 3.1 Distribution of crystal habits in the Jericho diamond population  3.1.3 Resorption The degree of resorption of the studied diamonds was estimated using the classification of McCallum et al. (1994), which is based on 6 classes (Fig. 3.3). The diagrams shown on top of the distribution histogram in Fig. 3.3 were used as a term of visual comparison to assign each diamond its proper resorption class. Overall, the degree of resorption of the studied Jericho diamond is low, with the majority of samples falling into class 5 and 6 of McCallum et al. (1994). Twenty-three samples could not be ascribed to any resorption class, due to the lack of preserved surface features of the original crystal, and were marked as “unknown” in Fig. 3.3.  3.1.4 Crystal intactness and fracturing The majority of diamonds in this study are classified as “fragment” or “broken” (Fig. 3.4), with the rest of the population represented by intact crystals and fractions.  36  80  Number of stones  70 60 50  ?  40 30 20 10 0 1  2  3  4  5  6  Unknown  Resorption Classes (McCallum et al., 1994)  Fig. 3.3. Relative abundances of resorption classes in the Jericho diamond population.  Brittle fracturing, which might have occurred during mantle residence (protomagmatic fracturing, Robinson et al., 1979) as well as during mining and processing (technogenic fracturing) is the reason for the relatively low abundance of Fig. 3.2 Dark field images of Jericho diamonds collected under optical microscope. 319G: octahedron (colourless). 331X: macle (colourless). 318G broken octahedron (yellow). 312G(I): cube (colourless). 369R: rhombododecahedron (colourless). 071X: broken octahedron (pink). 378X: octahedron (colourless). 299Q: octahedral aggregate (colourless). 004: broken cube (brown). 344P: broken octahedron. 251X: octahedron (colourless). 302G(II): octahedral fragment (colourless). 340X: octahedron (colourless). 177G: broken macle (colourless).  fully intact crystals in the studied diamond population. The vast majority of diamonds from this study (171 out of 209) show brittle fracturing. Among these, only 5 samples  show protomagmatic fracturing, while the remaining 166 display technogenic fracturing.  37  3.1.5 Surface features The surface features observed in Jericho diamonds include etching pits (trigons, hexagons and tetragons); etching channels; frosting; hillocks; and radioactive damage green spots. Plastic deformation lines were not observed on any of the studied crystals. Negatively oriented trigonal etching pits, i.e. trigons oriented with the apex in the opposite direction with respect to the (111) octahedral face, were observed in 41% of the diamonds. Some of these diamonds also displayed trigonal pits oriented positively. Tetragonal pits were observed in 3%, and hexagonal pits in 2%. Etching channels appear on 5% of the studied crystals. Diamonds showing hillocks amount to 12% of the total population. Frosting was observed on the (100) faces of cubic crystals (6% of the total population). Radioactive damage spots, providing the crystals with the typical dark green hue, were identified in 2 of the studied diamonds.  80 70  Frequency  60 50 40 30 20 10 0 intact  broken  fragment  fraction  Fig. 3.4. Histogram showing degree of intactness versus frequency for all the studied diamonds. Intact = most of the original crystal preserved; broken= more than 2/3 of the original crystal is preserved; fragment = between 1/3 and 2/3 of the original crystal is preserved; fraction = less than 1/3 of the original crystal is preserved.  38  3.1.6 Body colour The vast majority of the studied diamonds from Jericho (191 out of 209) are colourless. Other colours observed in the studied populations include yellow (7 diamonds), brown (3 diamonds), grey (3 diamonds), pink (2 diamonds), and green (2 diamonds) (Fig. 3.5). Some examples of the body colours observed in the studied Jericho diamonds are shown in Fig. 3.2.  1.0%  3.4%  1.0% 1.4%  1.4%  colorless brown green yellow pink grey  91.8%  Fig. 3.5 Pie diagram showing the distribution of body colours in the Jericho diamond population  3.2 Cathodoluminescence and growth studies The cathodoluminescence of 10 polished slabs cut from Jericho diamonds was examined both under optical and scanning electron microscope (SEM). The CL colours displayed by Jericho diamonds, rather common for natural stones, range from light blue (Fig. 3.6A,C,I) to turquoise (Fig. 3.6G, H) to green (Fig. 3.6E). Greyscale SEM CL images of the polished diamond plates (Fig. 3.7) show complex growth zonations. In diamonds 390R and 365X (Fig 3.7A and B respectively), parallel growth layers indicate the growth of the {111} octahedron. By contrast, diamonds 338R, 397P and 255X (Fig 3.7D, E, and H respectively) display curvilinear concentric zonation patterns typical of resorbed diamonds. Mineral inclusions  39  exposed on the surface of the polished diamond plates appear in SEM-CL images are dark spots due to the CL inactiveness of silicates such as garnet or clinopyroxene. It is worth noticing that circular dark haloes, are seen around the exposed mineral inclusions (Fig. 3.7B, D, and H). The origin of these structures is unclear: they might indicate internal stress due to a change in the inclusion’s volume with changing p-T conditions, or they might be due to a different N content and/or aggregation state in the area around the inclusions.  Fig. 3.6 Cathodoluminescence images of Jericho diamond plates collected under optical microscope. A. sample 390R; B. sample 365X. C. sample 389G. D sample 338R. E. sample 397P. F. sample 401P(II). G. sample 345P. H. sample 255X. I sample 395G(II). J. sample 037A. Scale bars are 500µm.  40  Fig. 3.7. Cathodoluminescence images of Jericho diamond plates collected under SEM. A. sample 390R; B. sample 365X; C. sample 389G. D sample 338R. E. sample 397P. F. sample 401P(II). G. sample 345P. H. sample 255X. I sample 395G(II). J. sample 037A. All scale bars are 500 µm, except for E and H, where scale bars are 200 µm.  In Fig. 3.6B and 3.7B, two clinopyroxene inclusions exposed on the diamond plate’s surface can be seen. Both in the optical and in the SEM image it is clear that the two grains are enclosed in different growth layers of the host diamond.  41  3.3 Nitrogen concentration and aggregation state Examples of FTIR spectra collected from Jericho diamonds are shown in Fig. 3.8. The blue spectrum (sample 316G) shows high absorption for both A and B centers (Type IaAB diamond), with a well developed B’ peak (platelets peak). The red spectrum (sample 327G) shows moderately low absorption of A centers, very low absorption of B centers (Type IaA diamond), and no B’ peak.  Fig. 3.8. FTIR spectra of Jericho diamond. The blue spectrum was collected from sample 316G. The red spectrum was collected from sample 327G.  The concentration and aggregation state of nitrogen defects in the 54 diamonds from Jericho analyzed with FTIR are summarized in Table 3.1. Nitrogen concentration ranges from below detection to 1433 ppm for total nitrogen, from below detection to 1044 ppm for A centers, and from below detection to 622 ppm for B centers. In most samples (67%) the 42  total nitrogen content is below 100 ppm, yet two samples (316G and 361G) registered relatively high N contents (1433 and 1408 ppm respectively) (Fig. 4.9). The percentage of B aggregates varies from 0 to 66% with an average of 7.5%. Diamond Type was determined on the basis of configuration of spectral lines in the one phonon region. The relative abundances of diamond types are shown in Fig.3.10: Type II (11%), Type IaA (63%) and Type IaAB (26%). Multiple spectra were collected from diamonds that had been cut and polished for cathodoluminescence studies (see previous paragraph). Nitrogen contents measured in different growth sector of the same diamond show slight differences, ranging from 10% (out of an average total N content of 44 ppm in sample 395G(II)) to 22% (out of an average total N content of 22 ppm in sample 338R). However, spectra collected from two different spots within the same growth sector also showed differences in the total N content (8% in sample 365X, and 17% in sample 338R). Table 3.1 Nitrogen content and aggregation state in diamonds from Jericho Sample ID  Average of1  N content (ppm)  A (ppm)  B (ppm)  %B aggregates  012 052G(II) 052P 054B 058 062G 076G 116X 171G 172 210X 255X 256X 266P 280X 284X 289G 298R 302Q  1 1 1 1 1 2 2 2 2 2 1 2 2 1 1 2 1 2 1  963 67 62 47 96 40 BDL 87 88 231 69 22 189 30 23 25 44 24 25  576 67 62 34 96 37 69 88 167 33 22 189 30 23 22 40 18 25  387 BDL BDL 13 BDL 3 18 BDL 64 36 BDL BDL BDL BDL 3 4 6 BDL  40 BDL BDL 27 BDL 8 21 BDL 28 52 BDL BDL BDL BDL 13 10 25 BDL  H peak at 3107 cm-1  x x x  x  BDL=below detection limit 1 averages are calculated after deconvolution of spectra taken on different spots on the diamond’s surface  43  B’ platelets peak at 1370 cm-1  x  Table 3.1 Nitrogen content and aggregation state in diamonds from Jericho (continued) Sample ID  Average of  N content (ppm)  A (ppm)  B (ppm)  %B aggregates  H peak at 3107 cm-1  303Q 304QJK 308G(I) 308G(IV) 312G 312X(I) 314X 316G 316R 318G 325X(I) 325X(II) 327G 328P 329P 331G(I) 331G(II) 334G 338R 340G 343P 355Q 361G 362Q 363R 365X 372G(II) 373G 374G(II) 375G 377X 378(II) 384R 395G(II) 414  1 1 2 1 1 1 1 4 1 2 1 1 1 2 2 2 1 3 2 1 2 1 2 1 2 3 1 1 1 1 2 1 2 3 1  914 59 80 BDL 151 74 42 1433 47 479 49 53 64 21 1044 154 BDL 355 24 921 BDL 170 1408 231 180 41 BDL 72 625 731 26 26 25 49 43  622 53 80 151 74 42 811 47 343 49 53 49 21 1044 154 120 24 921 170 1332 231 180 41 72 450 607 15 26 17 39 43  292 6 BDL BDL BDL BDL 622 BDL 136 BDL BDL 15 BDL BDL BDL 235 BDL BDL BDL 76 BDL BDL BDL BDL 175 124 11 BDL 8 10 BDL  32 11 BDL BDL BDL BDL 43 BDL 28 BDL BDL 23 BDL BDL BDL 66 BDL BDL BDL 5 BDL BDL BDL BDL 28 17 41 BDL 33 20 BDL  x  B’ platelets peak at 1370 cm-1  x  x x  x  x x  x  x  x  x  x x  x x  BDL=below detection limit 1 averages are calculated after deconvolution of spectra taken on different spots on the diamond’s surface  Other features observed with FTIR include the platelets peak at 1370 cm-1, detected in 7 samples, and the hydrogen peak (i.e. the peak related to the C-H atomic bonds) at 3107 cm-1, detected in 13 samples (Table 3.1).  44  11%  26% Type IaA  63%  Type IaAB Type IIa  Fig. 3.10. Diamond type distribution for Jericho diamonds (n=54)  Fig. 3.9 Distribution of total nitrogen concentration for Jericho diamonds (n=54). MDL = minimum detection limit for nitrogen (20 ppm)  3.4 C isotopes The carbon isotopic compositions of 71 diamonds from Jericho are listed in Table A1 (Appendix A). The δ13C values of the diamonds show a roughly bimodal distribution, with a peak between -39‰, and -35‰, and another small peak around -5‰ (Fig. 3.11)., with an overall average of 32‰. Strongly negative δ13C values (-24.6‰ to 39.4‰)  indicate  that  Jericho  diamonds contain isotopically light carbon. The smaller peak in the histogram (Fig. 3.11) seen at a value (~4‰) is typical of carbon Fig. 3.11 Distribution of δ13C values for Jericho diamonds  stored in the mantle (e.g. Cartigny et al., 1998).  45  3.5 Mineral inclusions in diamonds Both syngenetic and epigenetic inclusions were found in Jericho diamonds. The lines of evidence that were used in this study to distinguish between syngenetic and epigenetic inclusions are illustrated in section 2.6.1. Fifty-seven of the grains that were extracted from or exposed on the polished surface of the 42 diamonds selected for this study were classified as syngenetic inclusions. The most abundant mineral species among such inclusions is garnet (46), followed by clinopyroxene (7), olivine (2), milleritic sulphides (2), orthopyroxene (1), hematite (1), and diamond (1) (Table 3.2). Epigenetic inclusions are abundant in Jericho diamonds, however only 5 of the grains identified as epigenetic inclusions under optical microscope were extracted from their host diamonds and analyzed for major element chemistry. The most common mineral species observed among extracted epigenetic inclusions are phlogopite and serpentine. Oxides such as ilmenite and spinel are often found associated with phlogopite inclusions. It is worth noting that the only polimineralic inclusions observed in Jericho diamonds are epigenetic, all the syngenetic inclusions being monomineralic. Table 3.2. Inclusions recovered from Jericho diamonds. Inclusion species and number No. of diamonds garnet (3) 3 garnet (2) 4 garnet (1) 23 garnet (6) + cpx (1) 1 garnet (3) + cpx (2) 1 garnet (2) + cpx (1) 1 garnet (1) + cpx (1) 1 garnet (6) + phlog. (2) 1 garnet (5) + phlog.(1) + serp (1) 1 garnet (2) + phlog (1) + opx (1) 1 cpx (2) 3 cpx (1) 2 olivine (2) 1  Paragenesis eclogitic eclogitic ecl. and webst. eclogitic eclogitic eclogitic eclogitic eclogitic websteritic eclogitic eclogitic eclogitic peridotitic  Abbreviations: cpx=clinopyroxene; phlog.=phlogopite; serp=serpentine; opx=orthopyroxene; ecl=eclogitic; webst=websteritic  46  In the following paragraphs, the characteristics of all diamond inclusions analyzed in this study will be presented in detail.  3.5.1 Garnet Forty-six garnets were recovered from 26 host diamonds. In most cases, garnet was the only syngenetic mineral species present, although it was found in coexistence with clinopyroxene in 5 diamonds and with orthopyroxene in 1 diamond. Grains range in size from <20 to ~200μ and are typically orange in colour. Several shades of orange were observed among Jericho garnet inclusions (Fig. 3.12), from dark orange-red to almost colourless. However, caution must be used in classifying these inclusions’ colour: larger grains normally tend to show a more intense colour, and quite often the colour seen on the inclusion while inside its diamond host looks different once the grain is extracted. No clear correlation between the garnet inclusions’ colour and their major element chemistry is observed.  Fig. 3.12. Garnet inclusions in diamonds from Jericho showing different shades of orange.  47  Most garnet inclusions have euhedral shapes and in many cases the superimposed octahedral morphology of the host diamond can be observed (Fig. 3.13). The major element chemistry of garnet inclusions in Jericho diamonds is shown in Table 3.3. The garnet population in Jericho diamonds has Mg# ranging from 0.39 to 0.70, grossular content between 12 and 30%. TiO2 content between 0.29 and 0.80 wt% and Na2O between 0.06 and 0.11 wt% (Table 3.3). Garnets found coexisting within the same diamond host have very similar compositions, with  Fig. 3.13. Garnet inclusion showing superimposed octahedral morphology (scalebar is 100μ).  differences ranging within 4 wt% for each element. The only exception to this is diamond 611 (Table 3.3), where one garnet shows lower FeO (11.70 versus ~17.50 wt%) and higher MgO contents (19.62 versus ~13.65 wt%) than other 2 garnets coexisting with it. No zonation or significant compositional inhomogeneity was observed within single garnet inclusions. Low Cr contents (<1.00 wt% Cr2O3) would suggest that all the garnets recovered from Jericho diamonds are eclogitic or websteritic. Some of the garnets with higher Mg-numbers (0.6-0.7) and Cr2O3=0.3-0.8 wt% coexist with orthopyroxene, whereas none of such garnets were found in coexistence with clinopyroxene.  3.5.2 Clinopyroxene, orthopyroxene and olivine Seven clinopyroxenes were recovered from six host diamonds, mostly in coexistence with garnet. Clinopyroxenes in Jericho diamonds are typically smaller than garnets (<10  48  Table 3.3. Major element chemistry of syngenetic garnet diamond inclusions Inclusion 395G(II)-2 405X-1 1716-1 058-2 2860-1 average of 2 1 1 2 1 Mineral ecl. garnet ecl. garnet ecl. garnet ecl. garnet web. garnet host diamond 395G(II) 405X 058 2860 298R SiO2 40.03 39.90 38.78 40.23 40.84 TiO2 0.80 0.72 0.61 0.69 0.54 Al2O3 22.17 21.94 21.80 22.26 22.75 Cr2O3 0.15 0.14 0.04 0.02 0.81 FeO 15.82 16.43 18.13 15.34 10.03 MnO 0.39 0.38 0.47 0.39 0.30 MgO 13.99 13.13 11.50 15.12 19.54 CaO 6.53 6.87 7.45 5.54 4.29 Na2O 0.12 0.12 0.11 0.11 0.06 61 58 53 63 77 Mg# Total  Inclusion average of Mineral host diamond SiO2 TiO2 Al2O3 Cr2O3 FeO MnO MgO CaO Na2O Mg# Total  100.00  99.62  284X-6 1 ecl. garnet 284X 40.96 0.58 23.03 0.09 11.54 0.30 17.86 4.95 0.09 73  284X-7 1 ecl. garnet 284X 41.12 0.62 23.17 0.09 11.69 0.34 18.02 4.98 0.08 73  99.40  99.89  280X-1 2 ecl. garnet 280X 39.44 0.74 21.94 0.12 17.16 0.40 12.82 6.84 0.11 57  100.11  99.58  298R-1 1 ecl. garnet 298R 41.08 0.42 23.36 0.13 12.59 0.49 16.24 6.25 0.08 69  298R-5 3 ecl. garnet 284X 39.88 0.80 22.13 0.11 16.22 0.43 13.35 6.90 0.11 73  284X-2 2 ecl. garnet 284X 41.03 0.60 23.04 0.10 11.86 0.35 17.90 4.89 0.09 72  284X-3 2 ecl. garnet 284X 40.88 0.60 22.96 0.08 12.09 0.31 17.71 5.00 0.09 73  284X-4 2 ecl. garnet 284X 40.74 0.61 23.10 0.09 11.96 0.31 17.88 4.95 0.08 73  284X-5 1 ecl. garnet 284X 40.75 0.59 23.03 0.12 11.93 0.34 17.80 4.91 0.08 73  99.72  99.54  99.69  99.15  100.65  99.92  99.87  99.72  362Q-3 1 web. garnet 362Q 42.13 0.51 23.73 0.28 8.65 0.29 20.67 4.09 0.07 81  362Q-4 1 web. garnet 362Q 41.92 0.49 23.49 0.28 8.63 0.32 20.68 4.10 0.06 81  399X-2 1 web. garnet 399X 41.52 0.52 23.02 0.69 8.60 0.27 20.48 4.21 0.07 81  399X-3 1 web. garnet 399X 41.36 0.51 23.03 0.66 8.54 0.31 20.54 4.28 0.06 81  399X-4 2 web. garnet 399X 41.82 0.48 23.20 0.71 8.41 0.31 20.52 4.21 0.07 81  399X-5 1 web. garnet 399X 41.83 0.48 23.15 0.78 8.72 0.28 20.46 4.28 0.06 81  399X-6 2 web. garnet 399X 41.84 0.29 23.61 0.69 8.44 0.32 20.53 4.11 0.05 71  363R-1 1 ecl. garnet 363R 41.08 0.58 22.85 0.18 11.91 0.37 18.13 4.32 0.06 73  100.43  99.97  99.37  99.29  99.75  100.05  99.89  99.49  49  Table 3.3. Major element chemistry of syngenetic garnet diamond inclusions (continued) Inclusion 377X-1 377X-2 377X-3 401P-1 076G-1 076G-2 average of 2 3 2 1 4 4 Mineral ecl. garnet ecl. garnet ecl. garnet ecl. garnet ecl. garnet ecl. garnet host diamond 377X 377X 377X 401P 076G 076G SiO2 40.21 40.01 40.09 41.61 40.11 40.10 TiO2 0.65 0.69 0.68 0.30 0.61 0.61 Al2O3 21.05 21.32 20.94 23.02 21.26 21.25 Cr2O3 0.18 0.18 0.18 0.14 0.10 0.13 FeO 18.15 17.74 18.07 10.79 17.81 17.89 MnO 0.37 0.38 0.36 0.32 0.41 0.40 MgO 13.82 13.97 13.87 19.63 12.78 12.78 CaO 5.75 5.69 5.65 4.27 6.97 6.96 Na2O 0.10 0.12 0.11 0.10 0.10 0.12 Mg# 58 58 58 76 56 56 Total  Inclusion average of Mineral host diamond SiO2 TiO2 Al2O3 Cr2O3 FeO MnO MgO CaO Na2O Mg# Total  100.14  076G-3 3 ecl. garnet 076G 40.09 0.62 21.16 0.09 17.69 0.37 12.76 6.93 0.10 56  611-1 4 ecl. garnet 611 40.01 0.68 21.34 0.11 17.48 0.41 13.17 6.86 0.09 57  611-2 2 ecl. garnet 611 41.80 0.29 22.87 0.21 11.17 0.40 19.62 4.24 0.05 75  611-3 2 ecl. garnet 611 40.18 0.68 21.36 0.11 17.46 0.44 13.13 6.75 0.12 57  302Q-1 2 ecl. garnet 302Q 40.28 0.77 21.20 0.10 16.97 0.39 13.17 7.33 0.12 58  100.23  99.82  100.16  100.66  100.21  100.34  100.28  100.08  99.95  100.17  302Q-2 1 ecl. garnet 302Q 40.44 0.72 21.28 0.07 17.02 0.42 13.08 7.15 0.11 58  302Q-4 2 ecl. garnet 302Q 40.28 0.78 21.20 0.10 16.77 0.41 13.27 7.20 0.11 58  384R-1 2 ecl. garnet 384R 41.23 0.63 22.15 0.12 12.67 0.29 17.76 5.37 0.09 71  384R-3 2 ecl. garnet 384R 41.41 0.63 22.16 0.09 12.43 0.34 17.90 5.20 0.09 72  344X(I)-1 2 ecl. garnet 344X(I) 41.67 0.53 22.55 0.38 10.91 0.36 19.51 4.65 0.07 76  344X(I)-2 2 ecl. garnet 344X(I) 41.56 0.51 22.58 0.35 11.07 0.33 19.59 4.62 0.08 76  344X(I)-3 2 ecl. garnet 344X(I) 41.70 0.51 22.40 0.33 10.86 0.34 19.39 4.63 0.08 76  344X(I)-4 2 ecl. garnet 344X(I) 41.99 0.53 22.39 0.38 10.53 0.32 19.77 4.51 0.07 77  344X(I)-5 2 ecl. garnet 344X(I) 41.38 0.53 22.42 0.34 11.35 0.37 19.05 4.74 0.07 75  344X(I)-6 2 ecl. garnet 344X(I) 41.41 0.51 22.54 0.36 10.93 0.32 19.70 4.74 0.08 76  393-2 2 ecl. garnet 393G 40.17 0.67 21.25 0.10 17.45 0.43 13.18 6.73 0.11 57  100.31  100.12  100.30  100.24  100.62  100.68  100.27  100.49  100.26  100.59  100.09  50  to ~50μ), and appear as colourless, anhedral grains with elongated shapes (Fig. 3.14). Imposed octahedral morphology is is as evident as in garnet inclusions. The major element chemistry of clinopyroxenes in Jericho diamonds is shown in Table 3.3, together with other mineral species found as inclusions. Jadeite contents of clinopyroxenes are  Figure 3.14. Clinopyroxene inclusions in diamond  between 10% and 22%, therefore clinopyroxenes should be classified as omphacites. K2O wt% ranges from below detection (<0.04) to 0.15. Mg#’s vary from 0.66 to 0.84 (Table 3.4). One orthopyroxene inclusion was recovered from a diamond which also contained seven garnet inclusions (diamond 362Q). The orthopyroxene is characterized by an Mg# of 0.89 and a CaO content of 0.49 wt% (Table 3.4). Two olivine grains were extracted from the same diamond host (343P(I)). The two grains appeared as subrounded colourless grains, when observed under optical microscope. They show very similar chemical compositions, with Mg#’s of 0.93, very low NiO content (0.09 and 0.06 wt%) and CaO below detection limit (Table 3.4).  3.5.3 Milleritic sulphides, hematite and diamond Four black subhedral to euhedral inclusions were extracted from 4 diamond hosts. Two were sulphides with NiO content as high as 70.8 wt% and total Fe content of 0.09 and 0.13 wt% (Table 3.4). Based on this, the two sulphides were classified as millerites. 51  Table 3.4. Major element chemistry of syngenetic diamond inclusions. Inclusion 256X-1 256X-2 116X-3 377X-4 377X-5 Av. of 3 4 1 2 1 Mineral ecl. cpx ecl. cpx ecl. cpx ecl.cpx ecl.cpx Host diamond 256X 256X 116X 377X 377X SiO2 TiO2 Al2O3 Cr2O3 FeO MnO MgO CaO Na2O K2O NiO Mg# Total  Inclusion Av. of Mineral Host diamond SiO2 TiO2 Al2O3 Cr2O3 FeO Fe2O3* MnO MgO CaO Na2O K2O NiO Mg# Total  54.34 0.20 2.39 0.03 3.15 0.09 16.91 20.53 1.39 0.08 90 99.11  54.37 0.21 2.37 0.05 3.16 0.08 16.91 20.57 1.38 0.09 90 99.18  362Q-6 1 web. opx 362Q  343P(I)-1 3 olivine 343P(I)  56.92 0.10 0.43 0.01 7.17 0.16 34.35 0.49 0.05 0.01 89 99.70  41.41 0.01 0.01 0.02 6.74 0.07 51.69 0.01 0.01 0.00 0.09 93 99.95  53.73 0.42 4.91 1.23 3.57 0.10 13.91 17.02 3.38 87 98.26  343P(I)-2 1 olivine 343P(I) 41.11 0.03 0.01 0.06 6.87 0.05 51.75 0.03 0.00 0.06 93 99.89  52  53.92 0.12 3.04 0.09 7.49 0.11 14.42 18.07 2.18 0.11 77 99.55  384R-2 3 ecl.cpx 384R  55.00 0.18 2.85 0.10 7.16 0.07 13.92 17.83 2.28 0.10 78 99.49  54.56 0.19 2.60 0.03 5.16 0.09 17.24 18.07 1.61 0.08 85 99.63  55.00 0.21 2.67 0.17 3.67 0.04 16.08 20.04 1.73 0.15 89 99.78  367Q(II)-5 1 mill. sulph. 367Q(II) 367Q(II)  314X-1 1 hematite 314X 0.01 0.00 0.01 0.00 0.01 99.54 0.08 0.11 0.01 0.00 0.00 99.77  344X(I)-7 2 ecl.cpx 344X(I)  S  28.52  Fe  0.09  Co Cu  0.15 0.37  Ni  70.79 100.00  One grain, characterized by a sharp, flat octahedral habit, was analyzed as Fe oxide. Stoichiometric calculations allowed to identify it as hematite (Table 3.4), a very unusual mineral among diamond inclusions. Finally, one black grain that displayed a sharp octahedral habit when inside its diamond host (a characteristic typical of chromite inclusions), turned out to be an octahedral diamond covered by a thin layer of graphite, which came off as soon as the grain was extracted by mechanical crushing.  3.5.4 Epigenetic inclusions Epigenetic inclusions are very abundant in Jericho diamonds. Occasionally they are found coexisting with syngenetic inclusions in the same diamond host (Table A2), but in general they are found in diamonds characterized by alteration to graphite and systems of Table 3.5. Major element chemistry of epigenetic diamond inclusions Inclusion 284X-1 362Q-5 362Q-8 343P(II)-2 Av. of 1 1 1 1 Mineral phlogopite phlogopite phlogopite phlogopite Host diamond 284X 362Q-5 362Q-8 343P(II) SiO2 TiO2 Al2O3 Cr2O3 FeO MnO MgO CaO Na2O K2O BaO Cl F Total  41.79 2.21 12.58 0.47 3.98 0.00 24.46 0.00 0.44 9.80 0.21 0.04 0.01 95.98  41.10 0.90 14.34 0.31 3.87 0.00 24.02 0.00 0.48 9.96 0.12 0.22 0.07 95.39  40.56 1.31 13.90 0.51 3.87 0.00 23.94 0.00 0.43 10.16 0.10 0.15 0.10 95.06  53  41.75 2.27 12.24 0.42 4.10 0.01 24.28 0.05 0.50 9.84 0.17 0.07 0.10 95.79  399X-6 1 serpentine 399X  367Q(II)-3 1 spinel 367Q(II)  367Q(II)-6 1 ilmenite 367Q(II)  38.27 0.31 3.80 1.07 8.67 0.30 31.82 0.19 0.08 0.23 0.11 0.14 84.99  0.05 4.57 3.19 51.69 26.52 0.32 10.23 0.04 0.00 0.00 96.61  0.05 51.86 0.00 0.19 41.48 3.57 0.90 0.01 0.02 0.00 98.08  cracks and veins that do not contain  any  syngenetic  minerals. Epigenetic inclusions show irregular shapes and are internally inhomogeneous both in terms of colour and in terms of chemical composition (Fig. 3.16). The most common mineral species found as epigenetic inclusions  Fig. 3.15. TiO2 vs. FeO plot comparing the composition of phlogopite diamond inclusions (DI) with phlogopites found in the Jericho kimberlite and in the eclogitic xenoliths from the Jericho kimberlite.  in Jericho diamonds are phlogopite and serpentine (Table 3.5). Small (<10μ), euhedral oxide grains (such as spinel and ilmenite) are often found within phlogopite inclusions. The composition of phlogopite inclusions is compared in Fig. 3.15 with the composition of phlogopites found in the Jericho kimberlite  and  in  the  eclogitic  xenoliths from the kimberlite itself. Phlogopite diamond inclusions clearly show  affinity  phlogopites, Fig. 3.16. Reflected light image of epigenetic inclusions of phlogopite including oxide grains.  with  kimberlitic  confirming  epigenetic nature.  3.5.5 Trace element chemistry of garnet and clinopyroxene inclusions Twelve (out of 46) garnets and 6 clinopyroxenes (out of 7) extracted from the Jericho diamonds were analyzed for their trace element chemistry.  54  their  Results of laser ablation analyses on these inclusions are presented in Table 3.6. Garnet diamond inclusions display REE patterns similar to most eclogitic garnet diamond inclusions worldwide (Stachel et al., 2004), with low LREE (0.05 – 5 times chondritic) and high HREE (30-80 times chondritic) (Fig. 3.17B,C). Three garnets (399X1, 399X2, and 384R1, Fig. 3.17B) display a subtle negative Eu anomaly. Concentrations of REEs in clinopyroxene range from 20-60 times chondritic for LREE to 1-3 times chondritic for HREE (Fig. 4). Four out of 6 clinopyroxenes (256X1, 256X2, 377X6, and Fig. 3.17. Chondrite-normalized rare earth elements (REE) patterns for clinopyroxene (A) and garnet (B and C) inclusions in Jericho diamonds. Shaded fields represent worldwide DI (Stachel et al, 2004). Here and further chondritic trace element abundances are from McDonough and Sun (1995).  393G1) display subtle negative Eu anomalies. All clinopyroxene  inclusions show enrichment in LREE with respect to the field of diamond inclusions worldwide (Stachel et al., 2004) (Fig. 3.17A).  55  Table 3.6. Trace element chemistry of garnet and clinopyroxene diamond inclusions from Jericho Sample ID 061I3 076G1 076G2 344X2 362Q2 377X1 377X2 384R1 393G2 Mineral  399X1  399X2  256X1  256X2  377X6  377X7  384R2  393G1  %RSD  Detection limit (ppm)  garnet  garnet  garnet  Garnet  garnet  garnet  garnet  garnet  garnet  garnet  garnet  cpx  cpx  cpx  cpx  cpx  cpx  Cr  N/A  570.10  602.60  N/A  4423.00  4181.00  N/A  4187.00  N/A  N/A  481.10  270.60  276.50  360.50  N/A  N/A  322.20  2.6%  2.55  Ni  N/A  26.08  25.62  N/A  84.67  74.88  N/A  65.18  N/A  N/A  33.09  330.70  329.30  230.20  N/A  N/A  258.60  4.6%  0.82  Sc  N/A  91.28  95.04  N/A  53.45  N/A  N/A  N/A  94.87  96.10  93.56  25.16  26.08  20.15  N/A  N/A  25.38  6.1%  0.29  V  N/A  336.70  349.70  N/A  358.10  N/A  N/A  N/A  312.60  306.70  328.70  533.20  537.50  309.50  N/A  N/A  442.80  3.6%  2.54  Rb  N/A  N/A  4.98  N/A  4.43  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  42.01  21.7%  0.56  Sr  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  N/A  111.00  112.80  123.40  N/A  N/A  199.70  8.2%  2.52  Y  N/A  49.46  50.39  N/A  13.31  N/A  N/A  N/A  50.01  39.74  39.17  8.60  9.36  4.62  N/A  N/A  24.16  4.3%  0.10  Zr  N/A  44.21  46.01  N/A  18.96  N/A  N/A  N/A  52.57  33.36  34.66  14.16  15.44  11.90  N/A  N/A  24.16  5.8%  0.15  Hf  N/A  0.78  0.94  N/A  N/A  N/A  N/A  N/A  0.83  0.72  0.77  0.82  0.66  0.58  N/A  N/A  0.80  5.5%  0.12  Nb  N/A  BDL  BDL  N/A  3.77  N/A  N/A  N/A  BDL  0.36  N/A  N/A  N/A  N/A  N/A  N/A  0.84  11.6%  0.29  Ba  5.26  6.01  16.57  2.15  0.40  30.64  6.42  8.85  N/A  0.84  0.04  1.72  6.25  N/A  1.71  1.71  17.81  12%  1.30  Pb  N/A  BDL  BDL  N/A  10.41  N/A  N/A  N/A  BDL  1.75  BDL  BDL  BDL  1.17  N/A  N/A  1.43  8.6%  0.59  La  ≤0.22  ≤0.34  ≤0.28  0.06  ≤0.01  ≤0.02  ≤0.12  ≤0.03  ≤0.27  ≤0.05  ≤0.07  4.60  4.68  ≤0.01  9.05  5.24  7.04  22%  0.54  Ce  ≤1.04  ≤1.41  ≤1.3  0.44  ≤0.14  ≤0.19  ≤1.09  ≤0.21  ≤1.39  ≤0.27  ≤0.77  15.90  14.91  ≤0.34  27.46  17.08  28.70  58%  2.16  Pr  ≤0.44  ≤0.37  ≤0.35  ≤0.09  ≤0.09  ≤0.09  ≤0.24  ≤0.10  ≤0.37  ≤0.21  ≤0.24  2.80  2.70  ≤0.13  4.46  2.68  4.62  33%  0.93  Nd  2.45  3.25  3.11  1.29  ≤0.53  0.73  2.74  ≤0.67  2.61  1.50  2.29  13.48  13.87  1.70  22.04  9.86  17.50  26%  0.70  Sm  1.30  1.61  2.02  1.03  0.77  0.81  0.84  0.60  1.03  1.09  1.32  2.75  2.36  1.08  3.53  2.60  3.53  24%  0.63  Eu  ≤0.62  ≤0.68  0.76  ≤0.45  ≤0.32  ≤0.37  ≤0.70  ≤0.27  ≤0.61  ≤0.54  0.73  ≤0.71  ≤0.71  ≤0.37  0.88  ≤0.66  0.82  26%  0.72  Gd  3.54  3.58  3.59  2.19  2.10  1.90  2.29  1.72  3.88  4.22  3.81  2.97  3.48  1.96  2.95  2.34  3.14  16%  0.39  Tb  0.76  0.87  0.81  0.62  0.46  0.57  0.50  0.53  1.15  0.62  0.80  0.37  ≤0.35  0.57  ≤0.29  ≤0.20  ≤0.26  16%  0.37  Dy  8.34  7.71  8.22  7.13  5.15  5.24  5.70  5.37  9.03  8.39  7.13  2.55  2.47  5.38  2.09  2.02  1.80  17%  0.39  Ho  2.13  1.86  2.15  1.45  1.40  1.35  1.73  1.40  2.35  1.85  1.83  0.38  0.33  1.36  0.38  ≤0.22  ≤0.25  13%  0.29  Er  6.82  6.30  6.74  5.63  4.89  4.75  4.18  5.51  10.01  6.49  6.56  1.04  0.81  5.16  0.82  0.79  0.75  15%  0.33  Tm  1.19  1.04  1.19  0.98  0.78  0.83  0.54  0.82  1.16  1.17  1.12  ≤0.13  ≤0.06  0.81  ≤0.09  ≤0.05  ≤0.05  12%  0.28  Yb  7.73  7.48  8.45  7.09  6.04  5.68  6.93  6.94  9.68  8.04  6.99  0.52  0.47  5.58  0.48  ≤0.34  ≤0.32  18%  0.43  1.27 1.14 1.40 0.97 0.87 1.05 1.15 1.05 1.29 All values are in ppm. Abbreviations: BDL=below detection limit; N/A=not analyzed  1.48  1.07  ≤0.06  ≤0.04  1.02  ≤0.06  ≤0.06  ≤0.03  13%  0.28  Lu  56  4. Origin of Jericho eclogites and Jericho diamonds 4.1 Petrography of eclogites and websterites from the Jericho kimberlite Eclogites and websterites account for respectively 25% and 8% of the population of mantle xenoliths in the Jericho kimberlite. Most of the petrological characteristics of the Jericho xenoliths illustrated hereafter are taken from Kopylova et al., 1999a,b. Eclogitic xenoliths show both massive and foliated textures, the latter being more abundant. Extensive replacement of the primary garnet-clinopyroxene assemblage is seen more frequently in the foliated xenoliths. Massive eclogites are characterized by coarse grained (1-5 mm) granoblastic textures with subhedral garnet (25-65%) and clinopyroxene (10-55%) (Fig. 4.1A). Garnet can also be found as large round euhedral inclusions in clinopyroxene oikocrysts. Accessory phases include rutile (1-3%), zircon, and, occasionally, diamond. Rutile is found either as subhedral large (0.1-3 mm) grains or as lamellae in garnet. Zircon is present as small (0.05-0.1 mm) grains in poikilitic garnets. Olivine (015%) is observed in some samples as subhedral grains (1-3 mm) or in intergrowths with clinopyroxene. Primary clinopyroxene in normally more altered than garnet, showing corroded margins where fine grained, secondary minerals such Figure 4.1. Photomicrographs of foliated (A) and massive (B) eclogites from Jericho.  as chlorite and serpentine are observed.  Foliated eclogites are constituted mainly of garnet (40-50%) and clinopyroxene (1040%), with rutile (0-7%), zircon (0-1%), kyanite (0-20%), and apatite (0-5%) as 57  accessory phases. Secondary minerals (chlorite + phlogopite + carbonate) are also present in alteration zones. The anisotropic texture of these rocks is controlled by shape preferred orientation of phases and only in rare cases by mineralogical banding (Fig. 4.1B). Such preferred orientation is determined by the preferential replacement of garnet and clinopyroxene along specific directions or planes by Fig. 4.2. Photomicrograph showing megacrystalline texture in a Jericho websterite.  volatile-rich secondary phases including phlogopite, alkali amphibole, clinopyroxene, and kelyphitic  aggregates after garnet. Rutile is found included in garnet as needles oriented along three {1 1 1} crystallographic planes, suggesting exsolution. In some samples, garnet shows compositional zonations characterized by different shades of colour. In those samples, clinopyroxene is almost entirely replaced by chlorite + phlogopite + carbonate. Primary kyanite is found as euhedral, tabular grains (0.5-2.0 mm) or as round inclusions in garnet. Kyanite also appears as radiating, fibrous aggregates, which are probably secondary. Accessory apatite grains (0.2-2 mm), instead, appear to be in textural equilibrium with primary constituent minerals. Websteritic xenoliths form the Jericho kimberlite are characterized by extremely large grain size (5-30 mm), curvilinear grain boundaries and the presence of exsolution lamellae and symplectite intergrowths (Fig. 4.2). These textures have been described by Kopylova et al. (1999a) as “magmatic allotriomorphic […] defined by subhedral orthopyroxenes and anhedral clinopyroxenes”. Clinopyroxene grains are larger than orthopyroxenes, yet clinopyroxene can be found as exsolution lamellae in orthopyroxene. 58  Olivine is present as anhedral grains along pyroxene boundaries and also as euhedral inclusions within clinopyroxene oikocrysts. Accessory phases include spinel, which is found included in garnet and clinopyroxene, ilmenite, pentlandite and pyrrhotite. ilmenite, pentlandite and pyrrhotite. Kopylova et al. (1999a) inferred a magmatic origin for the Jericho websterites based on their magmatic texture and the presence of unequilibrated mineral intergrowths which are unstable under mantle P–T conditions (Field and Haggerty, 1994; Passchier and Trouw, 1996).  4.2 Geothermobarometry and mantle stratigraphy Temperature estimates for Jericho eclogites and websterites were calculated using the Ellis and Green (1979) geothermometer. The methodology used for these calculations was the same applied to garnet-clinopyroxene DI pairs and illustrated in section 4.5. Eclogite xenoliths, at the assumed equilibrium pressure of 50 kb, record temperatures between 600 and 1150 oC (Fig. 4.3). No significant difference between the equilibrium temperatures of massive and foliated eclogites is observed. In the Jericho mantle column, reconstructed by Kopylova et al. Fig. 4.3. Histogram showing the frequencies of equilibrium temperatures calculated with Ellis and Green geothermometer (1979) on massive, foliated eclogites, and websterites from Jericho. Modified from Kopylova et al. 1999.  59  (1999b) (Fig. 4.4),  massive and foliated eclogites occur interleaved with peridotites over a depth range of 90-200 km (Kopylova et al. 1999a). A peculiar feature of the eclogite distribution in the N Slave mantle is the occurrence of diamondiferous eclogites in the deeper part of this interval (150-200 km, 950-1160 oC). Diamondiferous eclogite coexists with lithospheric peridotites at depths 150-170 km, and with high-T asthenospheric peridotite and younger websterite intrusions at depths> 170 km (Fig. 4.4).  Fig. 4.4. mantle stratigraphic column based on peridotitic P-T arrays (Kopylova et al, 1999 b) and on the depth distribution of eclogites. Yellow=garnet peridotite; light blu=massive eclogite; dark blue=foliated eclogite; purple=websterite; diamonds=diamondiferous peridotites and eclogites. Modified from Kopylova et al., 1999b.  4.3 Major and trace element chemistry of Jericho eclogites Major and trace element chemistry of primary garnets and clinopyroxenes from the Jericho eclogites are presented in Appendix C. The composition of minerals in the primary assemblage of Jericho eclogites has been characterized by several authors over the past decade (Kopylova et al., 1999b, 2004; Heaman et al., 2006). Primary garnet is pyrope-almandine and has very low contents of Cr (<0.2 wt% Cr2O3), Ti (<0.4 wt% TiO2), and Na (<0.13 wt% Na2O). Garnet in foliated eclogites shows higher Ca and lower Mg contents with respect to garnet in massive and diamondiferous eclogites (Appendix C, see also section 4.4). Some high-Mg garnets (MgO> 20 wt%) in massive and diamondiferous eclogites resemble garnets in Type A eclogites defined by Coleman  60  (1965) and Taylor and Neal (1989) (Fig. 4.12). Low-Mg garnets from foliated eclogites are more similar to Type B and C eclogites. Primary clinopyroxene in Jericho eclogites is enriched in Na and Al, and has been classified by Kopylova et al. (1999b) as omphacite. Clinopyroxene found in foliated eclogites has (on average) higher Na and lower Mg contents compared to clinopyroxenes in massive eclogites (Appendix C, see also section 4.4). Clinopyroxene from websterites instead displays much lower jadeitic contents and higher Cr (0.9-1.9 % Cr2O3) and has been classified as Crdiopside (Kopylova et al., 1999b). Clinopyroxene REE patterns show uniform “humped” shapes with the highest enrichment in medium rare earths and a relative depletion in light Fig. 4.6. Chondrite-normalized rare earth elements (REE) patterns for clinopyroxene (A) and garnet (B) from the Jericho eclogites. Minimum detection limits (MDL) are based on analytical ICP-MS conditions as described in Chen (1999).  and heavy REEs. In many of the studied clinopyroxene grains concentrations of heavy REEs are  below detection limit of the analytical technique. The normalized content of La in the clinopyroxenes varies greatly, from 2 to 10 times the chondrite abundances (Fig. 4.6A). In contrast to the clinopyroxene, garnet REE content show less spread between samples. All garnets 61  have highly fractionated light rare earth elements and flat, unfractionated heavy REE. The garnets are 10 times more depleted in La than chondrites and 9-30 times more enriched in HREEs (Fig. 4.6B). Subtle positive Eu anomaly is detected in some samples. REE compositions of the Jericho eclogite were reconstructed from the REE compositions of garnet and clinopyroxene and their modal abundances reported in Kopylova et al. (2004). Foliated eclogite shows Fig. 4.7. Chondrite-normalized rare earth elements (REE) patterns for the Jericho foliated eclogite (A) and massive eclogite (B) reconstructed based on the observed modal mineralogy (Kopylova et al. 2004). Greyfield encompasses a range of possible bulk REE patterns for Jericho diamondiferous eclogite. The latter are computed from analysed REE contents of DI under assumption that they have similar range of garnet and clinopyroxene modes as massive eclogites. The fields outlined by magenta dotted and dot-and-dash lines represent REE patterns for worldwide MORB and ophiolitic gabbros, respectively (Klein, 2003). Also shown is a REE pattern (red bold line) reconstructed for a 50% Gar -50% Cpx mix for eclogitic inclusions in the Diavik kimberlites (C. Slave) (Davies et al. 2004). The latter approximates bulk REE patterns for diamondiferous eclogites of the C. Slave.  uniform LREE-depleted patterns with a small positive Eu anomaly and chondrite-normalized HREE contents of ~10 (Fig. 4.7A). REE patterns of the massive eclogite (Fig. 4.7B) differ from those of foliated eclogites by the absence of the Eu anomaly, the magnitude of normalized REE  contents, complex shapes and by their generally higher fractionation of HREE.  62  4.4 Partial melting and metasomatic recrystallization of Jericho eclogites A suite of thirteen previously studied foliated and massive eclogites was thoroughly investigated by Kopylova (unpublished data) to check for partial melting and recrystallization of primary minerals. This suite of samples had been previously characterized in terms of bulk composition (Russell et al. 2001) as well as petrography, mineralogy and thermobarometry (Kopylova et al. 1999a,b, 2004). Primary paragenesis of garnet, clinopyroxene, olivine, orthopyroxene and kyanite in the Jericho eclogites underwent partial melting and formation of secondary garnet and diopside. This recrystallization is more pronounced in the foliated samples. In three samples of massive eclogites, two showed secondary clinopyroxenes ranging in abundance from 6 to 10 vol. %. Among 10 foliated eclogites, three contained 19-31 vol. % secondary clinopyroxene; secondary garnet (13 vol. %) occurred in one. The secondary clinopyroxene can form around primary omphacite in spongy rims and fractures. In inner parts of these rims, the clinopyroxene crystallizes is fine euhedral skeletal grains and becomes coarser towards the outer margin (Fig. 4.8A). Secondary clinopyroxene growing in fractures and mantling other grains of primary omphacite is euhedral (Fig. 4.8B). Secondary garnet similarly mm thick and show broad oscillatory zoning of euhedrally shaped bands (Fig. 4.8C, D). forms around primary garnet grains. These newly crystallized garnet mantles are 0.2-0.3 mm across. Margins of primary garnet occasionally demonstrate complex zoning, with irregularly shaped patches of Mg-rich composition (Fig. 4.8A). Both new garnet and clinopyroxene are severely zoned and garnet often becomes progressively more Mg-rich and Ca-poor toward the outer rim (Appendix C, unpublished data by Kopylova).  63  Fig. 4.8. SEM microphotographs of secondary clinopyroxene and garnet in Jericho eclogites. A: A grain of primary clinopyroxene (CpxP) is surrounded by polycrystalline secondary clinopyroxene (CpxS) that become coarser away from the primary clinopyroxene grain CpxP is more jadeitic than CpxS enriched in Ca and Mg. Primary garnet (light) shows irregular areas of magnesia recrystallization (areas of varied darker shades) on the contact with CpxS (sample 47-8). B. Recrystallization of primary clinopyroxene (darker patches) to fien grained aggregates of secondary clinopyroxene (lighter area) in fractures. Note euhedral shape of a thin rim of secondary clinopyroxene overgrowing primary clinopyroxene on the right side of the photograph (sample 52-5). C and D: Secondary oscillatory-zoned garnet growing around primary grain. 64 Scalebar is 200 microns.  4.4.1 Major element chemistry of primary and secondary minerals in eclogites Compositions of secondary minerals are compared with respective minerals from all types of Jericho eclogites (Fig. 4.6). For this comparison, we compiled a database of mineral compositions for diamondiferous Jericho eclogites (Appendix C) from published analyses of Kopylova et al. (1999a) and Heaman et al. (2006). The variations in MgO, Na2O and CaO content of clinopyroxene and garnet in diamondiferous eclogites are almost as large as those in massive eclogites, although the most magnesian minerals occur exclusively in diamondiferous samples (Fig. 4.6). Secondary clinopyroxene is always enriched in Ti, Ca and Mg compared to primary Na- and Alrich clinopyroxene from the same sample (Fig. 4.6B). Secondary garnet is richer in Mg ± Ti -rich and poorer in Ca (Fig. 4.6A).  Fig. 4.9. CaO (wt%) vs MgO (wt%) (A) and Na2O (wt%) vs MgO (wt%) (B) plots for primary and secondary garnets in Jericho eclogites. Fields for diamondiferous (vertically striped), massive (dotand-line) and foliated (dotted) eclogites (Kopylova et al. 1999a) are shown for comparison. Arrows are drawn from the primary to the secondary mineral of the same sample.  The shift in composition between primary and secondary minerals in barren eclogites shows that secondary minerals are more  65  similar to the ones found in diamondiferous eclogites.  4.4.2 Trace element chemistry of primary and secondary minerals in eclogites A subset of 7 samples from the suite of thirteen well characterized eclogites (see previous section) was analyzed for trace elements in primary garnet and clinopyroxene (Kopylova et al., 2004) (Fig. 4.10). Unpublished trace element data used for this work is listed in Appendix C. Several grains of primary and secondary clinopyroxene and garnet were to estimate the magnitude of trace element compositional changes related to recrystallization (Appendix C, Fig. 4.10). Secondary clinopyroxene in sample 47-8 is richer in all trace elements than primary clinopyroxene repeating the shape of the spidergram at a higher level of concentrations (Fig. 4.10A). The only exception is Ba, which is drastically more enriched in secondary grains. For clinopyroxene, recrystallization does not change the overall shape of REE patterns, but shifts the REE contents to higher values. Secondary garnet in sample 20-7 is also richer than primary in all trace elements but especially in Ba, Hf and Zr (Fig. 4.10B). Similar features, such as enrichment in Ba, Pb and LREE, depletion in Na in recrystallized eclogites from the Jericho kimberlite were described by Heaman et al. (2006). According to these authors, eclogites have been affected by multiple metasomatic events, as well as interaction with the host kimberlitic magma. Based on petrographic and geochemical characteristics of the recrystallized phases, Heaman et al. (2006) divided the metasomatic processes into Type 1 and Type 2. Type 1 metsomatism is characterized by growth of refractory minerals such as rutile and zircon, which determine a considerable enrichment in HFSE (Nb, Ta, Zr, Hf) with respect to the original bulk composition. The presence of zircon allowed Heaman et al. to date the recrystallization event attributed to Type 1 metasomatism: U-Pb radiogenic dating yielded ages between 403 and 1786 Ma. The oldest paleoproterozoic growth zone in zircon possibly developed 66  during the initial eclogitic metamorphism. The metasomatic enrichment in HFSE possibly  Fig. 4.10. Chondrite-normalized trace elements patterns for clinopyroxene (A) and garnet (B) from the Jericho DI and selected primary (P) and secondary (S) grains from eclogites. The analyses from eclogites are shown with connecting lines. Red lines are minimum detection limits.  occ urre  d prior to or during initial eclogitic metamorphism. Heaman et al. (2006) attribute the scatter in the isotopic data to late thermal event, responsible for episodic Pb loss and/or new zircon growth. 67  Type 2 metasomatism, instead, is characterized by the growth of minerals such as apatite, carbonates, phlogopite and possibly another Ba bearing phase. As a consequence, the new assemblage displays enrichments in P, Ba, and LREE. Reconstructed Nd bulk rock compositions of zircon bearing eclogites yielded mesoproterozoic ages (0.98-1.27 Ga) and Heaman et al., indicated this as the possible age of Type 2 metasomatism. Given the affinities in the Ba and LREE enrichments in recrystallized eclogites observed by Heaman et al. (2006) and in this study, the mesoarchean Type 2 metasomatism might also be responsible for the origin of diamonds.  4.5 Comparison of DI with minerals in diamondiferous eclogites and websterites 4.5.1 Major element chemistry Garnets found as inclusions in diamonds and in diamondiferous xenoliths at Jericho form single compositional trends. On the MgO-CaO plot (Fig. 4.11), DI and some analyses from diamondiferous eclogites form a trend of negative correlation between the oxides. On this trend, garnet from the eclogites occupies the most Mg-rich part and a separate low MgO, high CaO cluster (sample Lupin21). The magnesian end of the trend falls into  Fig. 4.11. CaO (wt%) versus MgO (wt%) plot comparing the chemistry of Jericho garnet inclusion and garnets from eclogitic xenoliths (Kopylova et al. 1999a, Heaman et al. 2006). Here and further an oval with horizontal striping encompasses compositions of garnet in Jericho websteritic xenoliths (Kopylova et al. 1999b).  68  worldwide field of “websteritic” DI (Stachel and Harris 2008), while the opposite end plots in the “eclogitic” field (Fig. 4.11). In Fig. 4.12 garnet DI are compared with garnets from eclogites and websterites in a Cr2O3 space like the one in Fig. 4.5. Importantly, garnets from Jericho websterite xenoliths display high Cr2O3 content dissimilar to compositions of Jericho DI (Fig.4.12). In Fig. 4.12. Cr2O3 (wt%) vs. TiO2 (wt%) for Jericho garnet DI. Also shown is a line at 0.4 wt.% Cr2O3 below which 98% of “eclogitic” DI plot (Stachel and Harris, 2008).  the worldwide context, garnets with very high  MgO content like those from Jericho diamondiferous paragenesis are uncommon and found only in Yakutia (Sobolev et al., 1999; Spetsius et al., 1999; Fig. 4.13). These should be classified as mantle Group A eclogites according to Coleman (1965) and Taylor and Neal (1989). Other diamondiferous eclogites reported from the Slave province (represented in Fig. 4.13 by the solid-line field) and from elsewhere are less magnesian and plot with crustal eclogites B and C (Fig. 4.13). Jericho garnets only partially overlap with these. Clinopyroxenes in Jericho diamonds and diamondiferous xenoliths also form continuous trends  Fig. 4.13. Ternary Ca-Mg-Fe (cations) diagram comparing the composition of garnet DI (diamonds) and garnets from diamondiferous eclogites from Jericho (circles and squares) with eclogitic garnet DIs from other locations in the Slave province (solid line field, Davies et al. 2004; Pokhilenko et al. 2004; Tappert et al. 2005) and with eclogitic garnet DI from Yakutia (dotted line, Sobolev et al. 1999), South Africa (dashed line field, Appleyard et al. 2004; Phillips et al. 2004), and Botswana (dash and dot line field, Richardson et al. 1999). Subdivisions refer to eclogite classification by Coleman (1965) and by Taylor and Neal (1989).  69  Fig. 4.14. A. A plot of Na2O (wt%) versus MgO (wt%) comparing the chemistry of clinopyroxene in Jericho DI and eclogitic xenoliths. Here and further an oval with horizontal striping encompasses compositions of clinopyroxenes in Jericho websteritic xenoliths (Kopylova et al. 1999b); an oval with vertical striping – clinopyroxenes from diamondiferous eclogites (Kopylova et al. 1999a, Heaman et al. 2006). B: Mg# vs Cr/(Cr+Al) (mol) plot for clinopyroxenes from Jericho DI, Jericho eclogites and websterites, and worldwide “eclogitic” and “websteritic” DI Stachel and Harris (in press). Mg, Fe, Cr and Al are cations calculated per 6 oxygens. C: The same in a Na vs Al (cations, calculated for 6 oxygens) plot. Shaded fields represent compositions of clinopyroxenes from barren foliated eclogites; fields outlined dot-and-dash lines represent compositions of clinopyroxenes from barren massive eclogites (Kopylova et al., 1999a and unpublished data, see Appendix C).  70  in various compositional spaces. On the Na2O-MgO plot (Fig. 4.14A), clinopyroxenes from the diamondiferous eclogites comprise a large compositional field, and DI clinopyroxenes plot entirely within the field. The majority of clinopyroxene analyses has higher Mg and lower Na than clinopyroxenes in massive barren or foliated eclogites. Only analyses from diamondiferous eclogite Lupin 21 stand out due to lower MgO and higher Na2O and overlap with foliated and massive clinopyroxenes (Fig. 4.14A). On the 100 Mg/Mg+Fe – 100 Cr/ Cr+Al plot (Fig. 4.14B) and Na-Al plot (Fig. 4.14C) Jericho clinopyroxenes occupy an area of overlapping fields for worldwide eclogitic and websteritic DI with exception of DI 116X-3 and eclogite Lupin 21. By Cr2O3 content, the clinopyroxenes contrast more chromian clinopyroxenes from Jericho we websterite xenoliths (Fig.4.14B).  4.5.2 Geothermobarometry Calculated EG temperatures for diamond inclusions at 50 kbar are confined in an interval between 1100 and 1160oC (Table 4.1). The analogous temperature estimates for 16 samples of diamond-bearing eclogites (Kopylova et al., 1999a; Heaman et al. 2006) yield 970-1140oC (Table 4.1). Both DI and diamondiferous plot well within the diamond stability field, based on the Jericho geotherm calculated applying Brey and Kohler’s termobarometer (1990) to peridotitic xenoliths (Kopylova et al., 1999b) (Fig. 4.15). The temperatures of origin of diamond inclusion pairs are higher than those observed for garnets and clinopyroxenes from xenoliths. This may be an artifact of calculating temperatures for non touching DI, which was shown to overestimate temperatures (Meyer 1987). The exact temperatures and pressures of eclogite formation in the asthenospheric section of the mantle are not possible to constrain because the calculated geotherm shows a thermal perturbation in this region, possibly related to kimberlite magmatism 71  (Kopylova et al., 1998b). In the asthenosphere, estimated temperatures span a wide range and shift to higher values, as xenoliths here sample two thermal states separated in time (Kopylova et al. 1999b). Since there is no indication whether eclogites are equilibrated with younger high-T peridotite or with older peridotite at a relatively low steady-state geotherm, we assign a large field of possible thermodynamic parameters to deep diamondiferous parageneses (shaded field in Fig. 4.14).  Fig. 4.15. Pressures and temperatures of equilibrium for Jericho diamondiferous parageneses. Equilibrium temperatures were calculated using Ellis and Green geothermometer (1979). Thin lines inidicate univariant P-T lines for DI constrained by Table 6. Symbols show intersections of these lines (not plotted for diamondiferous eclogites) with the BK Jericho geotherm (Kopylova et al. 1999b). The geotherm is steady state above 160 km (thick line) but perturbed to a higher thermal state in the deeper asthenosphere (thick dashed line). Pressures of formation cannot be unambiguously defined for parageneses that intersect a 32 transient segment of the Jericho geotherm and shown as lighter or dashed symbols. The area of possible pressures and temperatures of equilibration for diamondiferous parageneses in the asthenosphere is shaded. Diamond/Graphite boundary from Kennedy and Kennedy (1976). Mantle stratigraphic column is reproduced from Kopylova et al. (1999a).  72  Table 4.1. Equilibrium temperatures for coexisting garnet-clinopyroxene pairs. T at 40 kb (oC) T at 50 kb (oC) Intersection with the BK Jericho (Ellis and Green, 1979) (Ellis and Green, 1979) geotherm (Kopylova et al., 1999b) Sample ID 377X 384 R 344X 393 G Sample ID LGS017MX14 131-I Lupin-20 Lupin-21 EC1(JDF6) Sample ID 135-F*1 135-F*3 135-F*4 135-F*5 135-F*6 135-F*7 123-F*  Diamond inclusions 1120 1150 1120 1150 1100 1130 1010 1040 Diamondiferous eclogites of Kopylova et al. (1999) 960 996 995 1067 971 1007 1055 1091 969 1005 Diamondiferous eclogites of Heaman et al., (2006) 950 990 980 1020 980 1010 960 1000 980 1020 980 1020 970 1010  T (oC) 1200 1200 1160 1050 T (oC) 975 1100 1000 1120 1100 T (oC) 950 1000 1000 975 1000 1000 975  P (kb) 64 64 60 50 P (kb) 46 54 48 56 54 P (kb) 44 48 48 46 48 48 46  4.6 Modeling the origin of the diamondiferous eclogitic assemblage 4.6.1 Partial melting and metasomatism of Jericho eclogites Abundant evidence suggests the eclogites are residues of melt extraction. Firstly, enrichment of secondary minerals in Mg may have resulted from a preferential extraction of relatively low-T end-member components from garnet and clinopyroxene solid solutions, i.e. grossular, almandine and jadeite. The leaching of jadeite would be even more effective in the presence of hydrous fluids (Ryabchikov et al. 1982). Secondly, a prior melt extraction event that modified compositions of diamondiferous eclogites after formation of diamonds is witnessed by the contrasting chemistry of garnet and clinopyroxene inside and outside diamond. Garnets and clinopyroxenes that crystallized outside of diamond in diamondiferous eclogites are more Mgrich than the DI garnet and clinopyroxene (Fig. 4.14A) and compared to them are depleted in 73  incompatible Na, Al (Fig. 4.14A), Rb, Ba, La, Ce, Pr and HREE (Fig. 4.10). Finally, the lower SiO2 and higher MgO contents of cratonic kimberlite-derived eclogites, including Jericho samples (Russell et al., 2001), as compared to MORB, are conventionally accounted for by extraction of tronjemite-tonalite melts from partially molten subducted slab (Ireland et al. 1994; Jacob 2004). Reconstructed REE patterns of the Jericho eclogites are depleted in LREEs with respect to MORB (Fig. 4.7) as expected of residues. The recrystallization of the Jericho eclogite, however, cannot be ascribed solely to an isochemical partial melting, as new grains of garnet and clinopyroxene are enriched in incompatible trace elements (Ba, Zr, Hf) (Fig. 4.10) and cannot be refractory residues. This metasomatism also changed REE patterns of garnet (Fig. 4.10B) from fractionated, characteristic of eclogitic DI worldwide, to almost flat, more typical of peridotitic DI garnet (Stachel et al 2004). Furthermore, crystallization of secondary phlogopite, amphibole, Nb rutile and apatite implies the influx of K-, P, Nb, Ti and H2O-rich fluid. The Jericho metasomatism is less alkaline, but more phosphorus-rich than the MARID or phlogopite-ilmenite-clinopyroxene metasomatism (Luth 2003 and references therein). Recrystallization of eclogitic minerals into secondary magnesian diopside and pyrope is a common phenomenon in eclogites (Hills and Haggerty 1989; Taylor and Neal, 1989; Ireland et al. 1994; Misra et al., 2004, Taylor and Anand 2004; Aulbach et al. 2007). It may have happened during entrainment in kimberlite melt (Ireland et al. 1994; Misra et al. 2004; Taylor and Anand 2004) resulting from partial melting of the eclogite associated with the influx of hydrous K-rich fluids at shallow depth (Misra et al. 2004; Taylor and Anand 2004). The metasomatism occurs in several consecutive stages (Misra et al. 2004) and may be associated with diamond formation (Spetsius 1999).  74  The metasomatism and partial melting that affected Jericho eclogites was also a repetitive long process separated in time into several “pulses”. Isotopic studies of Jericho eclogites established several periods of metasomatic overprints, i.e. the Paleoproterozoic timing (~ 1.8 Ga) for the N Slave HFSE metasomatism and the Mesoproterozoic (1.27-0.98 Ga) ages for a second metasomatic overprint introducing Ba, P and LREE and leading to growth of apatite, barite and phlogopite. Multiple evidence for the ancient metasomatism included U-Pb zircon data and model Nd TDM ages (Heaman et al. 2006). Besides these old events, the eclogites were affected by relatively recent partial melting and crystallization which produced unequilibrated textures and severe mineral zoning (Fig. 4.8) predating kimberlite emplacement for no more than several thousand years (Smith and Boyd 1992). Jericho metasomatic overprints that introduced amphibole may have occurred at P<23 kb (Luth 2003); other events must have happened deeper, in the garnet stability field, as indicated by REE patterns of the massive eclogite. Since the Jericho metasomatism and partial melting is prolonged and complex, it cannot be ascribed solely to the influence of kimberlite. Nevertheless, we cannot reject a possibility that the most recent metasomatic pulses are related to pre-kimberlitic fluids, as they are K- and Ba-rich and crystallize phlogopite, barite, apatite and niobian rutile (Mitchell 1995), i.e. the same minerals that grew metasomatically in Jericho eclogites.  4.6.2 Eclogite protoliths Bulk compositions of all Jericho eclogites (Russell et al. 2001) are identical to picrites (LeBas 2002) or their plutonic counterparts, being high in MgO (12-20 wt%), low in total alkalis (0.8-3 wt%) and SiO2 (41-47 wt%). Ultramafic picritic protolith is thus a viable predecessor for the eclogites. Mafic protolith affected by subsequent melt extraction is also possible, as the  75  Jericho eclogites have trace and major element characteristics of partial melting residues of mafic crustal rocks. The protolith of the foliated eclogite formed at shallow-mid crustal levels. The presence of the positive Eu anomaly implies that the magmatic predecessor of the foliated eclogite must have experienced minor accumulation of plagioclase. Its shallow origin is further supported by the absence of HREE fractionation and of equilibration with garnet that occurs deeper in the lithosphere. MOR basalts or gabbros (Fig. 8) of the subducted oceanic crust or low-pressure mafic cumulates in the continental crust (Barth et al. 2002) are some possible protoliths for the eclogite. An origin of the foliated eclogites in subducting oceanic crust is, however, favoured by their ages. The broad similarity of formation ages for zircon-bearing foliated eclogites with the ages of easterly subduction on the Western Slave Craton, led Heaman et al. (2006) to suggest that the eclogites may have formed as subducted slabs ~ 1.88-1.84 Ga ago. Preserved remnants of Proterozoic subducted oceanic crust were mapped beneath the Slave by various geophysical methods (Bostock 1997; Cook et al. 1999). Massive eclogites of the Jericho pipe have a different origin. Massive eclogites are more magnesian and less titanian and sodic than foliated eclogites. While this pattern can be ascribed to the ultramafic nature of the protolith (Heaman et al. 2006), it is not the unique explanation. The magnesian character of the massive samples may be a secondary feature related to melt extraction and mantle metasomatism. It is supported by 1) the development of secondary magnesian minerals due to recrystallization and mantle metasomatism, and 2) the similarity of some recrystallized clinopyroxene in foliated eclogites to primary clinopyroxene in massive diamondiferous eclogites (Fig. 5B). Because of a possible effect of metasomatism, REE patterns of massive eclogites must be interpreted with caution and understanding that they may have reflected only the most recent 76  stage of the rock formation and in fact mask the true nature of the protolith. In contrast to foliated eclogites, massive eclogites show more fractionated HREEs and no Eu anomaly, although we base our comparison on only 3 samples. Two of them, with medium fractionation of HREE, may be characteristic of EMORB, whilst a whole-rock REE pattern with a strong HREE fractionation may record the metasomatic equilibration of massive eclogite at depths > 150 km, in the absence of plagioclase and in the presence of garnet.  4.6.3 Metasomatic origin of Jericho diamonds A broad similarity in the chemistry of eclogitic DI and minerals in Jericho diamondiferous eclogites implies that the compositions of both must have reflected the same processes active in the N Slave mantle. Multiple pulses of metasomatic activity and partial melting recorded in the Jericho eclogites suggests that metasomatism may have also been involved in the genesis of diamonds and their DI. Two lines of evidence support this. Firstly, by low Na2O and high contents of MgO (Fig. 4.14), Ba, HREEs, La and Ce (Fig. 4.10A), DI clinopyroxene is closer to recrystallized secondary clinopyroxene than to primary clinopyroxene in eclogites. Secondly, DI garnet is characterized by elevated Zr and Hf, typical of recrystallized eclogitic garnet (Fig. 4.10B). Broad resemblance of these compositions, nevertheless, does not mean that diamonds crystallized in the last, pre-kimberlitic partial melting event, but rather allow us to use recent processes recorded in eclogites as analogues for older events overprinted and concealed by a long residence in the mantle. A metasomatic origin for diamonds has been proposed in numerous studies based on multiple lines of evidence (e.g. Taylor et al. 1998; Spetsius 1999; Cartigny et al. 1998, Cartigny 2005; Stachel et al. 2004) and is an undisputed paradigm now. Our preferred hypothesis is crystallization of diamond from hydrous K-rich metasomatic fluid that carried isotopically light 77  carbon. Magmatic predecessors for metasomatised eclogites could be ultramafic or mafic. In the latter case, the magnesian character of the Jericho diamondiferous rocks is a consequence of several ancient partial melting episodes rather than a primary trait. The protoliths may have already contained isotopically light C of organic origin if they formed on the ocean floor, but the traditional subduction model often invoked for eclogitic diamonds (Jacob 2004 and references therein) fails to fully account for the isotopic composition of Jericho diamonds. Indeed, in the sedimentary geological record there is almost no δ13C-values as low (Schidlowski et al., 1983) as observed at Jericho (δ13C = -24 to -41‰). Diamonds in metamorphic terranes are also made of “heavier” carbon (e.g. De Corte et al. 1999; Cartigny 2005). Moreover, eclogitic diamonds worldwide have mostly mantle-like δ13C values at ~-5‰, rarely extending to values lower than 25‰ (e.g. Javoy et al. 1986; Galimov 1991). Apart from organic C, there are some other cratonic mantle reservoirs depleted in 13C. “Light” carbon (δ13C ~ -22 to -26‰) is characteristic of certain portions of the mantle beneath the Kaapvaal craton in southern Africa (Deines 2002). Interestingly, this 13C-depleted mantle carbon commonly makes up “websteritic” diamonds (Deines 2002; Deines and Harris 2004), although the reason for this has yet to be found. An example of such pattern is seen in Orapa and Letlhakane kimberlites, where “websteritic” diamonds are lighter in C composition (δ13C average =-19.35‰ in Orapa and -19‰ in Letlhakane) than “eclogitic” (δ13C =-12.5‰ and -6.7‰) and “peridotitic” (δ13C =-9.3‰ and -6.2‰, respectively) (Deines and Harris 2004). These 13Cdepleted “websteritic” and “eclogitic” diamonds and carbon in eclogites are restricted to a narrow range of temperatures of 1000-1100oC (Deines and Harris 2004), resembling the tight spatial localization of the Jericho diamondiferous eclogites. The origin of the 13C mantle depletion is currently debated; viable explanations include heterogeneity of the primordial mantle, kinetic effects, CO2 degassing and isotope fractionation 78  (Deines 2002 and references therein; Cartigny 2005). Considering isotope fractionation, a possible participating carbon species could be unbonded C or SiC (Deines 2002). A strong C fractionation leading to a significant 13C depletion is observed between unbonded C and all other C-bearing phases. In Siberian websterite xenoliths, where C are found as graphite intergrown with metasomatic phlogopite and as elemental unbonded dispersed carbon in silicates, the metasomatic graphite has composition -8 to -23, dispersed carbon - -22 to -27‰, significantly lighter in 13C than the coexisting carbonate (-5 to -7‰) (Galimov et al. 1989; Deines 2002). Such significant differences in the isotopic compositions of the coexisting C-bearing species are compatible with the theoretical C isotope fractionation factors (Fig. 15 of Deines 2002). Atomic carbon equilibrated with mantle carbonate (δ13C = -5‰) could readily have an isotopic composition between -25‰ and -15‰ (Deines 2002). If unbonded atomic C preferentially participates in diamond formation, it can make 13C-depleted diamonds. The activation mechanism of unbonded carbon dispersed in mineral crystal lattices, for formation of diamond may be similar to mechanism revealed by experimental growth of diamond. Experiments by Pal’yanov and Sokol (2009) showed that, in presence of a C bearing silicate/carbonate melt, C would crystallize in the form of metastable graphite at temperatures around 1400 oC. Metastable graphite would then convert completely into diamond when the temperature increases from 1400 to 1600 oC. In summary, known C isotopic reservoirs of the cratonic mantle (δ13C = -5 to -26‰) cannot be sole contributors to the source of Jericho “eclogitic” and “websteritic” diamonds (δ13C = -35 to -41‰). Although a Raleigh fractionation from a CH4-rich fluid may result in a preferential removal of heavier C isotopes and crystallization of diamonds with lower δ13C (Thomassot et al. 2007), this is also not a feasible explanation. The Jericho diamonds could not have grown through a Raleigh fractionation process from a methane-rich fluid as 1) the observed tight 79  distribution of 13C without a extended ‘tail” at a light C rejects any fractionation model from an initially heavier carbon; 2) an unrealistically high amount of Raleigh fractionation and carbon loss is required to make diamonds with δ13C= 35-41% from initial C with δ13C = -20‰; and 3) methane is an unlikely metasomatic agent as it inhibits diamond formation (Sokol and Pal’yanov 2008, Sokol et al. 2001). In the absence of other explanations, we have to resort to a yet unstudied, rare, and highly localized mantle reservoir of 13C-depleted C, like carbon with δ13C =-30 to -50‰ analyzed in the off-cratonic mantle xenoliths (Liu et al., 1998), as one of the sources for the Jericho diamonds. We conclude that diamonds formed metasomatically from an exotic mantle fluid depleted in 13  C. By analogy with the metasomatic fluid that brought about the recent partial melting of the  Jericho eclogites, the fluid may have been hydrous and potassic. Such fluids can carry up to 15 wt% of silicate solutes (Mibe et al. 2002), dissolve and transport C, and are very effective medium for diamond crystallization (Pal’yanov et al. 2007). Diamonds grow more readily from the vapor where the weight ratio of H2O to silicates is higher (Sokol and Pal’yanov, 2008). Moreover, fluids rather than melts are favoured as the most likely agents of metasomatism in the cratonic mantle (Bell et al. 2005 and references therein). The fluid does not invariably trigger diamond formation as evidenced by multiple episodes of barren metasomatism in the Jericho eclogites. If occurrence of diamondiferous eclogites and DI in the Jericho mantle could map the localization of metasomatism, it is restricted to 140-200 km. These depths center around the lithosphere-asthenosphere boundary. Such localization of the metasomatism is not accidental. Fluid should be abundant at the lithosphere-asthenosphere boundary, since magmatic activity in the N Slave mantle concentrates immediately below the base of the lithosphere (Kopylova et al. 1999b). Perhaps, areas of intensive mantle metasomatism similar to the metasomatism that 80  formed N Slave diamonds can be traced by occurrences of highly magnesian eclogites, “websteritic” diamonds and diamonds depleted in 13C.  81  5. Diamonds from the Wawa calc-alkaline lamprophyre - Results Eighty diamonds from the calc-alkaline lamprophyre of Wawa have been studied by Lefebvre (2004) for their morphology and color, and 41 diamonds from the same suite have been characterized for their N content and aggregation state of their nitrogen centers (Lefebvre, 2004). The results from that study are shown in appendix A and illustrated in sections 5.1 and 5.5. Thirteen more diamonds (total of 54) have been analyzed for N content and aggregation state as part of the present study and the results from those analyses are also included in section 5.1-5.5 and appendix A. The following chapter also includes results on the diamond fluorescence, optical cathodoluminescence and cathodoluminescence spectroscopy, major element chemistry of mineral inclusions, and C and N stable isotope systematics.  5.1 Diamond morphology and colors 5.1.1 Crystallographic habit The Wawa diamonds are highly variable in their primary growth forms (Fig. 5.2A). The majority of diamonds are either octahedral aggregates (44% of the population) or single octahedral crystals (26%). The sizes of crystals in the aggregates are typically coarse, to (less commonly) fine. The macrodiamonds comprise a coarse "tail" of a large suite of microdiamonds (12,000 stones <0.5 mm) extracted from this bulk sample. Single cubic and cubic-octahedral crystals and their aggregates, as well as macles are also observed (Fig. 5.2A); 48% of the Wawa diamond population is represented by single crystals. Only twenty-eight diamonds could be evaluated for crystal regularity, because the majority of samples are broken crystals and fine aggregates. The majority of the  82  Fig. 5.1 Varying crystal habits of the Wawa population. A. cube; B. coarse cubo-octahedral aggregate; C. cubo-octahedral aggregate; D. octahedron; E. octahedral coarse aggregate; F. macle; G. octahedral fine aggregate; H octahedral aggregate.  Wawa diamonds are distorted to some degree, which is common for diamond crystals (Harris et al. 1975), and 11% are near-equidimensional.  5.1.2 Colour and transparency The Wawa diamonds are colourless (50%), heterogeneous (24%), yellow (11%), black (3%), brown (10%), and grey (3%). All cuboids including the cubic aggregates are yellow in colour. The majority of octahedral single crystals and coarse aggregates, as well as all macles, are colourless (Table A2). The Wawa diamond population consists of 48% transparent crystals, 25% translucent crystals, 14% opaque crystals and 14% combination of opaque and translucent crystals. The transparent crystals are mostly colourless and a few yellow octahedral single crystal and coarse aggregates, as well as macles. The translucent crystals comprise all possible primary crystal forms and colours. 83  The opaque crystals are mostly fine grained aggregates which have some black body colouring. Crystals exhibiting the combination of translucent and opaque are mostly heterogeneous fine and coarse crystal aggregates.  5.1.3 Resorption and surface features The Wawa diamonds in general have experienced low degrees of resorption (Fig. 5.2B). Over half of the diamonds fall into resorption classes 4 to 6 of McCallum et al. (1994), whereby there are 22% in class 4, 38% in class 5, and 8% in class 5. Diamonds which have experienced Fig. 5.2. A. Histogram showing frequency of occurrence of different crystal habits in the Wawa diamond population. Symbols: C cubic; C-CA cubic coarse aggregate; C-O cubo-octahedral; C-O-C-A cubooctahedral coarse aggregate; O-CA octahedral coarse aggregate; O-FA octahedral fine aggregate; O-C/FA octahedral heterogeneous aggregate; U unknown; M macle. B. Histogram showing the frequency of occurrence of resorption classes in Wawa diamonds an the relative abundances of single crystals and aggregates. Resorption classes follow the classification scheme of McCallum et al., 1994.  extensive resorption (class 1 to 3) comprise only 21% of the population. Some crystals (14%) exhibit non-uniform (pseudohemimorphic) resorption, whereby one part of the crystal is  more strongly resorbed than another. In such cases both resorption categories were 84  recorded (Table A2). Resorption specific to octahedral crystals and octahedral faces on cubic-octahedral crystals is marked by the presence of shield-shaped laminae, trigonal pits, hexagonal pits, hexagonal pits containing etch pits and serrate laminae (terminology by Robinson 1979). Resorption specific to cubic crystals and the cubic face of cubicoctahedral crystals is identified by the presence of tetragonal pits. Other surface features specific to highly resorbed tetrahexedroid crystals are terraces and elongate hillocks which are seen on only 4% and 1% of the Wawa diamonds respectively. The low percentage of these two surface features is a reflection of the low degree of resorption of the Wawa diamond population. Late stage etching features present on the diamonds are ruts, shallow depressions, frosting and corrosion sculpture. The diamonds carry no evidence of deformation such as lamination lines.  5.2 Diamond fluorescence The twenty-five diamonds from Wawa selected for diamond inclusions studies were examined under ultraviolet light to evaluate qualitatively their fluorescence intensities and colours. Microphotographs taken using a 100 W light source with a UV exciter filter (360±20 nm) and barrier filter (420 nm) attached to a Leica MZ FLIII optical microscope, with a constant time of exposure to of 20 s are showed in Fig. 5.3. Five of the chosen  samples did not display any fluorescence. Samples Wawa39, 52, and 80 show bright blue fluorescence; Wawa 57 and 77 show bright turquoise fluorescence; Wawa29, 32, 43 45, 50, and 53 show a mix of weak blue and yellow fluorescence; Wawa9, 10, 14, 18, 36, 49, 51, 58, and 60 show weak blue fluorescence.  85  Fig. 5.3. Fluorescence images of diamonds from Wawa. Numbers on the top left corner of each image are sample IDs.  86  5.3 Diamond cathodoluminescence Diamonds are grouped in six categories based on observed optical CL colours (Fig. 5.5, 5.6). The relative abundances of cathodoluminescence colours, based on the analysis of 69 diamonds, are as follows: orangered (46%), yellow (28%), orangegreen (10%), green (6%), and other, heterogeneous colours (10%) (Fig. 5.5). Interestingly, none of the Wawa diamonds exhibited common blue cathodoluminescence. The description of CL spectra below is based on the Fig. 5.5. Diagram showing the frequency of occurrence of cathodoluminescence colors in the Wawa diamond population  PeakFit deconvolution results. The  procedure finds unequivocal positions of only sharp peaks and assigns a non-unique combination of peaks to wider maxima. Therefore we give precise positions of the peaks only if they are stable irrespective of the parameters of the deconvolution. In diamonds with the red-orange CL colour, the SEM-CL spectral analysis reveals a sharp line at 575.5 nm, typically associated with several broader peaks in the red region of the spectrum between 586 and 664 nm. Broad peaks of lower intensity are also observed in the green region (around 520 nm) and in the blue region (around 440 nm) (Fig. 5.7). The relative intensities of the peaks show considerable variations in different samples and also in different spots of the same sample. In diamonds with yellow and green-yellow cathodoluminescence the main peak occurs in the green region of the visible spectrum, around 520 nm. The sharp line at 575.5 nm is also present, although it was not observed in all samples and all the analyzed spots 87  Fig. 5.6. Cathodoluminescence images of Wawa diamonds collected under optical microscope. Scalebars are 500 µm. Numbers on the top left corner of each image are sample IDs.  (Fig. 5.7). The asymmetric shape of the main 520 nm band deconvolutes to several smaller peaks between 543 and 610 nm.  88  Fig. 5.7. A plot of CL emittance intensity (in arbitrary units) versus emitted wavelengths (in nm) for Wawa diamonds representative of different CL colours. Blue spectrum of a diamond from the Juina area (Brazil) is shown for comparison. Spectra were integrated for 5s from the beginning of the electron beam irradiation.  In diamonds with yellow and green-yellow cathodoluminescence the main peak occurs in the green region of the visible spectrum, around 520 nm. The sharp line at 575.5 nm is also present, although it was not observed in all samples and all the analyzed spots (Fig. 5.7). The asymmetric shape of the main 520 nm band deconvolutes to several smaller peaks between 543 and 610 nm. In diamonds with green CL the main peak also occurs at 520 nm. In samples with good spectral resolution the sharp line at 575.5 nm is also observed. A broad peak of variable intensity at 440 nm is present in most samples (Fig. 5.7). The asymmetry of the 520 peak suggests the presence of additional peaks at 548-616 nm. In summary, CL emittance of all Wawa diamonds is controlled by a broad band at ~ 520 nm, a sharp peak  89  at 575.5 nm and several lines at 550- 670 nm. In contrast, diamonds with common blue CL feature prominent wide peaks at ~ 430-450 nm and 480-490 nm (Fig. 5.7).  5.4 FTIR Spectroscopy Combined FTIR spectroscopy data on Wawa diamonds from Lefebvre et al. (2004) and from the present study are presented in this section. FTIR spectroscopy indicates that the studied diamonds contain nitrogen and hydrogen. Nitrogen contents of the Wawa diamonds are between 0 – 932 atomic ppm (Table 5.1), with a mean nitrogen content of 137 ppm, a median of 89 ppm, and a mode below detection limit. The majority of Wawa diamonds have low nitrogen contents, below 300 ppm (Fig. 5.8). Heterogeneity in N contents is evident even in diamonds collected from the same outcrop, and that makes it difficult to distinguish diamond populations based on the location of sampling.  Fig. 5.8.Histogram showing the frequency of occurrence of total nitrogen concentrations in the Wawa diamond population. Colours represent different locations of sampling. Engagement zone comprises diamonds from Trenches E, E1, and E2.  90  5.4.1 Nitrogen concentration and aggregation state The Wawa diamonds show variable degrees of nitrogen aggregation. The majority of Wawa diamonds are Type IaAB (33%), and Type IaA (33%); the remainders are Type IIa (28%) and Type IaB (6%). Nitrogen aggregation states show a possible bimodal distribution (Fig. 5.9): the first mode, where the majority of the samples occur, has <30% aggregation in the B-form (mostly Type II and Type IaA diamonds); the second mode has a high aggregation state, with >60% B (group median 79% B). The paucity of mineral inclusion data does not permit assessment as to whether  Fig. 5.9. Diagram showing the relative abundances of nitrogen aggregation types in the Wawa diamond population.  diamo  nds with different aggregation states belong to the distinct diamond subpopulations. The higher abundance of B-centers does not correlate with a higher nitrogen content (Table A2), which is typical for most diamonds around the world (Stachel and Harris 1997). The distribution of N aggregation types in the different locations of sampling shows that diamonds extracted from polymict volcaniclastic breccias of Trench E-2 have generally less aggregated N defects with respect to diamonds from Trench E-1 (Fig. 5.10). 91  Fig. 5.10. Diagram showing the relative abundances (in %) of nitrogen aggregation types for each location where diamonds were sampled at Wawa. Each big square represents the total (100%) of stones collected from that location.  Table 5.1 Infrared characteristics of the Wawa diamonds (Modified from Lefebvre, 2004) Prog.  1 2 3 4 5 6 7 12 14 18 21 28 29 31 32 34 36 37 38 39 40 41 42 43 46 47 48 49 50  Location of sampling  Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E Trench E-1 Trench E-1 Trench E-1 Trench E-1 Trench E-1 Eng. zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone  a  Sample  GQE1-1 GQE1-2 GQE2-1 GQE2-2 GQE2-3 GQE2-4 GQE3-1 GQE4-5 GQE4-7 GQE4-11 GQE4-14 GQE5-2 GQE5-3 GQE6-1 GQE7-1 GQE8-2 GQE8-4 GQE9-1 GQE10-1 GQE10-2 GQE10-3 GQE10-4 GQE11-1 GQE11-2 GQE13-2 GQE13-3 GQE13-4 GQE13-5 GQE14-1  NA  a  NB  (ppm)  (ppm)  211 0 ND 14 ND 63 137 156 ND 214 102 30 124 43 ND ND ND 366 25 0 43 262 204 394 ND ND 12 66 49  63 66 ND 5 ND 19 0 133 ND 38 27 167 41 95 ND ND ND 54 41 145 59 0 0 0 ND ND 50 0 0  c  a  a  %B  Nt  b  Type  (ppm)  23 100 ND 27 ND 23 0 46 ND 15 21 85 25 69 ND ND ND 13 63 100 58 0 0 0 ND ND 80 0 0  275 66 ND 19 ND 81 137 289 ND 252 129 197 165 139 ND ND ND 421 66 145 101 262 204 394 ND ND 62 66 49  IaAB-p IaB* IIa IaAB-p IIa IaAB IaA IaAB-p IIa IaAB-p IaAB IaAB-p IaAB-p IaAB-p IIa IIa IIa IaAB IaAB IaB*-p* IaAB*-p IaA IaA IaA IIa IIa* IaAB-p IaA IaA*  92  3107 cm-1 H defect + + + + + + + + + -  c CH d Reg. stretch  + + + + + + + + + -  R I n/a I n/a R R R n/a R I I I I n/a n/a n/a I I I I R R R n/a n/a I R R  e  TNA (oC)  f  TNA (oC)  1134 n/a n/a 1208 n/a 1164 n/a 1158 n/a 1123 1149 1217 1149 1202 n/a n/a n/a 1107 1215 n/a 1198 n/a n/a n/a n/a n/a 1241 n/a n/a  1272 n/a n/a 1362 n/a 1308 n/a 1302 n/a 1259 1291 1373 1290 1355 n/a n/a n/a 1239 1370 n/a 1350 n/a n/a n/a n/a n/a 1402 n/a n/a  Table 5.1 Infrared characteristics of the Wawa diamonds (Modified from Lefebvre, 2004) Prog.  51 52 53 54 55 56 57 58 59 60 61 62 64 65 68 69 70 71 72 74  Location of sampling  Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. Zone Eng. zone "S5-J1" "S5-J1" "S6-J1" "S6-J1" "S6-J1" "S6-J1" "S6-J1" “KD3652”  Trench BZ “KD4214” Trench E-1 Trench E-1 Trench E-1 Trench E-2  a  Sample  GQE14-2 GQE14-3 GQE14-4 GQE15-1 GQE16-1 GQE16-2 GQE16-3 GQE16-4 GQE17-1 GQE17-2 GQE17-3 GQE17-4 GQE18-1 KD3652 KD3668-1 KD4214-1 KD4220-1 KD4224-1 KD4226-1 KD4229-2  NA  a  NB  a  a  %B  (ppm)  (ppm)  ND 78 96 ND ND ND 7 196 226 13 70 ND 0 105 177 ND 946 63 240 434  ND 663 0 ND ND ND 124 82 20 43 0 ND 25  ND 90 0 ND ND ND 95 29 8 77 0 ND 100  ND  ND  Nt  b  Type  (ppm)  ND 740 96 ND ND ND 132 277 246 55 70 ND 25 105 177 ND 946 63 240 434  IIa IaAB-p IaA IIa IIa IIa IaAB-p IaAB-p IaAB-p IaAB*-p* IaA IIa IaB*-p* IaA IaA IIa IaA IaA IaA IaA  93  c 3107 cm-1 H defect  + + + + + + -  c  CH d Reg. stretch + + + + * + + -  n/a I R n/a n/a n/a I R R I R n/a I n/a n/a n/a n/a n/a n/a n/a  e  TNA (oC)  f  TNA (oC)  n/a 1193 n/a n/a n/a n/a 1260 1141 1107 1239 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a  n/a 1344 n/a n/a n/a n/a 1426 1281 1240 1400 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a  Table 5.1 Infrared characteristics of the Wawa diamonds (Modified from Lefebvre, 2004) Prog. 75 76 77 78 79 70 71  a  Location of sampling  Sample  Trench E-2 Trench E-2 Trench E-2 Trench E-2 Trench E-2 Trench E-1 Trench E-1  KD4234-1 KD4234-2 KD4243-1 KD4231-1 KD4237-1 KD4220-1 KD4224-1  NA  a  NB  (ppm)  (ppm)  ND 198 334 686 444 946 63  ND  a  a  %B  Nt  b  Type  (ppm)  ND  ND 198 334 686 444 946 63  c 3107 cm-1 H defect  IIa IaA IaA IaA IaA IaA IaA  c  + + -  a  NA - nitrogen concentration in A-defects; NB - nitrogen concentration in B-defects; %B - percentage of B-defect; Nt - total nitrogen concentration; ND - not detected (i.e. below 10-15 atomic ppm nitrogen present); n/a - not available  b  * uncertain; p - platelet defect detected c  + = present; - = absent; * uncertain  d  R = regular; I - irregular; n/a = not available  e  mantle residence temperature (tMR) = 1.8 Ga mantle residence temperature (tMR) = 10 Ma  f  Eng. zone includes samples from Trenches E, E1, and E2, which are in close proximity (less than 300 m apart)  94  e  CH d Reg. stretch -  TNA (oC)  n/a n/a n/a n/a n/a n/a n/a  f  n/a n/a n/a n/a n/a n/a n/a  TNA (oC) n/a n/a n/a n/a n/a n/a n/a  Of the Type IaAB diamonds, 67% contain platelets; 3 diamonds with low aggregation states (< 25% B-defect) do not have platelets developed. Sixty five per cent of the diamonds are irregular and show much lower platelet peak intensities than would be expected from their content of A-centers (Fig. 5.11B). Wawa Type IaA diamonds do not contain either platelet peaks or B-defects, consistent with the observations of Woods (1986), according to which platelet peaks generally occur in diamonds with highly aggregated nitrogen defects. The distribution of N aggregation (% Fig. 5.11. A. A plot of N concentration (ppm) vs. content of B-centers (%IaB). Isotherms were calculated using the method of Taylor et al. (1990) for a maximum mantle residence time of 1.8 Ga (solid grey lines). Isotherms for a mantle residence time of 0.8 Ga are shown for comparison (dotted grey lines). The estimated temperatures are valid only for regular diamonds that are marked on the plot with error bars. The bars correspond to 20% error from the detection limits and deconvolution method (Stachel et al., 2002). When possible, diamond parageneses are inferred from inclusion studies. B. a plot of platelet peak intensity [I(B’)-absorption value of B’ peak after subtraction of the 2-phonon tail] divided by total absorption (µT) versus strength of A-center absorption (µA) divided by total absorption (µT). The error bars correspond to 20% uncertainty propagated through the funcionts plotted on X and Y axes. Regular trend is from Woods (1986)..  95  of B aggregates) with respect to N content is bimodal, with two clusters, characterized by similar N contents (90 ÷ 1000 ppm) but very different N aggregation (0 ÷ 30% of B aggregates and 70 ÷ 100% of B aggregates respectively) (Fig. 5.10A). If we look at  diamonds sampled from different locations, we notice that samples from the same outcrop can display extreme variations in terms of nitrogen aggregation, making it hard to use the location of sampling to distinguish between different diamond populations. However, it is worth noticing that all diamonds sampled from Trench E-2 have no B aggregates (Fig. 5.11A).  5.4.2 Hydrogen content in diamonds The presence of hydrogen in the studied diamonds is inferred by the presence of sharp FTIR peaks at 3107 cm-1 ascribed to the vibration of sp2 C-H bonds (Clark et al. 1992). The low intensity (0.01-0.21 relative absorption units) peaks are observed in ~5% of the diamonds (Table 5.1), typical of natural diamonds in general (Clark et al. 1992). The intensity of the 3107 cm-1 peak, however, cannot be an accurate measure of H content in diamonds, because the relative peak height is not proportional to H concentration and hydrogen in diamonds may occur in IR-inactive forms (Sellschop 1992). In addition to the 3107 cm-1 peak, other weak peaks resulting from stretching vibrations of the C-H bonds (McNamara et al. 1997) are detected in 60% of the samples in the 2750 to 3300 cm-1 range (Table 5.1).  5.5 Stable isotopes Sixty-one diamonds were analyzed for their C isotopic composition and, among those, 13 were also analyzed for their N isotopic composition. Sixty samples showed δ13C values ranging from -0.7 to -5.0‰, slightly higher, on average (-2.5‰), than the value of -5‰ assumed in literature for mantle carbon (e.g. Cartigny, 1998). Only one sample showed a considerably lower d13C, comparable to the values of organic matter in 96  Table 5.2. C and N isotopes in diamonds from Wawa prog #  sample #  δ13C (‰)  δ13N (‰)  1 2 5 7 8 10 11 13 16 17 19 20 22 23 24 25 33 34 36 37 38 39 40 41 42 43 44 46 47 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66  GQE1-1 GQE1-2 GQE2-3 GQE3-1 GQE4-1 GQE4-3 GQE4-4 GQE4-6 GQE4-9 GQE4-10 GQE4-12 GQE4-13 GQE4-15 GQE4-16 GQE4-17 GQE4-18 GQE8-1 GQE8-2 GQE8-4 GQE9-1 GQE10-1 GQE10-2 GQE10-3 GQE10-4 GQE11-1 GQE11-2 GQE12-1 GQE13-2 GQE13-3 GQE13-5 GQE14-1 GQE14-2 GQE14-3 GQE14-4 GQE15-1 GQE16-1 GQE16-2 GQE16-3 GQE16-4 GQE17-1 GQE17-2 GQE17-3 GQE17-4 GQE17-5 GQE18-1 KD3652 KD3653  -3.6 -1.7 -2.9 -4.4 -2.3 -1.5 -1.9 -0.8 -2.6 -1.6 -2.4 -1.1 -1.2 -1.7 -1.1 -2.3 -2.2 -2.2 -2.1 -2.9 -2.2 -2.0 -4.0 -2.0 -3.4 -5.0 -2.8 -3.2 -2.1 -4.3 -4.2 -1.7 -3.5 -4.5 -1.8 -1.9 -1.9 -4.1 -1.4 -2.8 -1.6 -1.3 -1.4 -5.0 -5.3 -1.6 -0.7  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 8.8 -17.6 N/A N/A -1.7 14.7 9.3 N/A N/A N/A N/A N/A N/A 0.7 N/A N/A N/A N/A 3.0 0.2 -4.2 N/A N/A N/A N/A N/A 1.6 N/A  97  prog #  sample #  δ13C (‰)  δ13N (‰)  67 68 69 71 72 73 75 77 78 79 80  KD3656-2 KD3668-1 KD4214-1 KD4224-1 KD4226-1 KD4239-2 KD4234-1 KD4243-1 KD4231-1 KD4237-1 KD4220-2  -3.6 -26.2 -1.7 -2.5 -4.7 -2.0 -1.7 -2.5 -4.2 -2.4 -3.4  N/A N/A N/A N/A 7.3 N/A N/A 1.8 5.8 0.6 N/A  subduction zones. Out of 13 diamonds analyzed for δ15N, 10 show positive values ranging between 0.7 and 14.7‰, whereas the remaining have negative values at -17.6, 4.2, and -1.7‰ (Table 5.2). No variation in neither C nor N isotopic values has been observed according to sampling locations.  5.6 Mineral inclusions in diamonds From the 25 diamonds selected for inclusion studies, 15 different phases have been analyzed from 14 diamonds, comprising 63 separate grains (Table 5.3). No inclusions were extracted from the remaining 11 diamonds. Inclusions were classified as primary or secondary based on their appearance under the SEM and on their positions within the diamonds. Inclusions of primary origin appear as competent faceted grains homogeneous in colour and chemical composition (Fig. 5.12A-C), not associated with any cracks in the host diamonds. By contrast, inclusions classified as secondary occur as amorphous heterogeneous grains, often bound to fractures in the diamond (Fig. 5.12D). Listed in Table 5.3 Primary inclusions recovered from Wawa diamonds. Inclusion species and No. of Paragenesis number diamonds olivine (1) 1 Peridotitic oliv. (1) + cpx (1) 1 Mixed oliv. (1) + cpx (2) 1 Mixed oliv. (1) + opx (2) + cpx (1) 1 Mixed oliv. (2) 2 Peridotitic oliv. (3) + an. (1) 1 Peridotitic oliv. (4) + opx (1) + alb. (1) 1 Peridotitic oliv. (4) + cpx (2) + Ni-Fe 1 Mixed sulph (1) Ni-Fe sulph. (1) + an. (1) 1 Unknown an. (1) + alb. (1) 1 Unknown Abbreviations: oliv.=olivine; opx=orthopyroxene cpx=clinopyroxene; an=anorthite; alb.=albite; Ni-Fe sulph.= Ni-Fe sulphide.  order of decreasing abundance, the primary inclusions recovered include: olivine, clinopyroxene, orthopyroxene, Fe-Ni sulphide, and plagioclase. No garnet or spinel inclusions were recovered. The phases typically occurring as secondary inclusions are  98  Fig. 5.12. Photomicrographs of mineral inclusions in Wawa diamonds. A. Olivine (sample KD4243-1); B. Orthopyroxene (sample GQE10-3); C. Albite (sample GQE15-1); D. Secondary chlorite developed along a diamond crack (sample GQE14-1).  biotite and chlorite, with a Na-Al-Mg-Fe silicate (smectite? glauconite?), an Al-rich silicate (Al2SiO5 polymorph?), Al-poor silicate (kaolinite? pyrophyllite?), K feldspar and K-Ni-Fe sulfide (djerfisherite?), Cu-Sb sulfide, K titanate (mathiasite? jeppeite?) and apatite in subordinate quantities. Biotite, chlorite and Na-Al-Mg-Fe silicate are all very variable in composition. However, a common feature observed in their EDS spectra is a  99  relatively high Fe peak, in many cases as intense as the Mg peak. The apatite is Sr-free and is found singly or in a fine mix with K titanate; Cu-Sb sulfide occurs mixed with Alpoor silicate. Aside from these intergrowths, no syngenetic or epigenetic touching inclusions were recovered from Wawa diamonds.  5.6.1 Olivine Olivine is the most abundant mineral inclusion in the diamonds. 18 olivine grains (5 to 80 um) are identified in 8 diamonds (Fig. 5.11A). Two different populations of olivine are observed. The first population has Mg# = molar Mg/(Mg+Fe) between 0.92 and 0.93, typical of subcratonic coarse, abyssal and ophiolitic peridotites (Boyd, 1989). The second population is higher in Fe and shows Mg-numbers of ~ 0.89, common to the most mantle peridotites worldwide, as well as mafic igneous rocks and sheared cratonic peridotites (Pearson et al. 2002). The NiO content is the same in both types of olivine and equal to 0.31-0.36 wt% (Table 5.4). The different olivines are found in association with different minerals. High-Mg olivine is found together with orthopyroxene, clinopyroxene, albite, anorthitic plagioclase and Fe-Ni sulphide, whereas Fe-rich olivine is only found in one diamond KD4243-1 in association with an anorthitic plagioclase (Table 5.4).  5.6.2 Clinopyroxene Eight clinopyroxene grains are identified in 6 diamonds. They are found in small (5 to 15 µm) faceted grains in association with high-Mg olivine, orthopyroxene, plagioclase and Fe-Ni sulphide (Table 5.4). EDS spectra of Wawa clinopyroxenes suggest that all grains have similar Cr-free, Fe-rich compositions. Due to the small size of the  100  clinopyroxene inclusion, only one grain yielded a reliable quantitative chemical analysis (Table 5.4). This grain is found in association with Fe-poor olivine and Ni-Fe sulphide, shows low Mg# (~0.65) and very low Cr2O3 (~0.09 wt%) content and is classified as omphacite (Deer, 1997) with 14 mol. % jadeite. The low-Cr and high-Fe (10 wt% FeO) character of the omphacite rejects the possibility of its peridotitic origin (as indicated by comparison with Cr-diopsides in cratonic peridotites, Pearson, 2002, and diamonds Viljoen, 1999), and with Mg-rich diopsides in off-cratonic peridotites (Deer 1997). The Wawa omphacite also contrasts with clinopyroxenes from all types of mafic parageneses, as their compositions are either poorer in Na (subcalcic augites) or richer in Ca (augites) (Deer et al. 1978). The only possible rock type which contains omphacite resembling that of the Wawa diamond inclusions is eclogite, specifically Type A (Coleman et al. 1965) mantle eclogite with high-Mg, low jadeitic omphacites (Deer et al. 1978).  5.6.3 Orthopyroxene Three orthopyroxene grains are found in 2 diamonds. Grains range in size from 5 to 60 µm and are subhedral to euhedral in shape (Fig. 5.11B). The orthopyroxenes show high Mg# (0.93) and low (~0.3 wt%) Al2O3 contents (Table 5.4). Such Mg-rich orthopyroxenes cannot be a part of eclogitic or websteritic diamondiferous assemblages (Viljoen et al. 1999). The orthopyroxenes clearly belong to the Wawa diamondiferous peridotitic paragenesis, as its Mg-number is slightly higher that the Mg-number of the coexisting olivine. Such Mg-Fe partitioning was predicted theoretically and for an equilibrated peridotitic assemblage, and is also commonly found in cratonic mantle peridotites (Pearson et al. 2002). Judging by Al2O3 below 2 wt %, orthopyroxenes were  101  equilibrated with garnet in mantle peridotites (Smith 1999), rather than in the spinel or plagioclase facies (McDonough and Rudnick 1998).  5.6.4 Sulphides Two Ni-Fe sulphide inclusions are identified in 2 diamonds. They are found in association with high-Mg olivine, orthopyroxene, clinopyroxene and plagioclase 5.1). Sulphide grains are usually small in size (less than 10 µm) and extremely homogeneous in composition, with Fe and Ni being the two major peaks. The sulfides are classified as Fe-rich pentlandite. Its high Ni content (25 wt% Ni; Table 5.3), however, cannot be taken as a proof of its peridotitic origin. There is no clear dichotomy in compositions of sulfides in eclogitic and peridotitic diamonds on the Kaapvaal craton (Pearson et al. 2002), and our unpublished data shows that high-Ni sulfides such as pentlandites (15-34% Ni) and millerite (49-72% Ni) are very common in the Slave craton eclogite, as evidenced by Jericho kimberlite xenoliths.  102  Table 5.4 Major element chemistry of inclusions in Wawa diamonds. olivine  olivine  olivine  orthopyroxene  clinopyroxene  albite  Fe-Ni Sulphide  77_3  80_1  9_2  40_2  52_2  54_1  46_2  KD42431  KD42202  GQE4-2  GQE10-3  GQE15-1  GQE143  39.62 < mdl 0.04 0.06 12.13 46.42 0.14 0.04 0.04 0.31 < mdl 98.80  40.81 < mdl < mdl 0.07 6.78 50.17 0.09 < mdl < mdl 0.36 < mdl 98.32  41.39 < mdl < mdl 0.05 6.53 50.30 0.10 0.41 < mdl 0.35 < mdl 98.79  57.78 < mdl 0.34 0.23 4.22 36.21 0.08 0.41 0.03 0.11 < mdl 99.43  54.62 0.31 3.38 0.09 9.74 17.78 0.24 10.63 1.94 0.18 0.58 99.47  66.85 0.54 19.27 < mdl 1.05 0.05 0.24 0.03 11.18 0.08 0.06 99.38  Si4+ 0.996 1.004 1.011 1.986 Ti4+ N/A N/A N/A N/A 3+ Al 0.001 <mdl <mdl 0.014 3+ Cr 0.001 0.001 0.006 0.006 Fe2+ 0.255 0.139 0.133 0.121 Mg2+ 1.739 1.840 1.832 1.855 Mn2+ 0.003 0.002 0.002 0.002 2+ Ca 0.001 N/A <mdl 0.015 + Na 0.002 0.001 <mdl 0.002 Ni2+ 0.006 0.007 0.007 0.003 K+ N/A N/A N/A 0.001 Total 3.004 2.996 2.995 4.005 Legend: <mdl=below detection limit; N/A=not analyzed  1.993 0.008 0.145 0.002 0.297 0.967 0.007 0.416 0.137 0.005 0.027 4.006  2.957 0.018 1.005 N/A 0.039 0.003 0.009 0.001 0.959 N/A 0.004 4.999  Mineral Inclusion No. Host diamond SiO2 TiO2 Al2O3 Cr2O3 FeO MgO MnO CaO Na2O NiO K2O Total  103  S  36.49  Fe Co Cu  35.46 0.46 0.40  Ni  25.05 97.92  Fe  5.300  Co Cu  0.06 0.04  Ni  3.600 9.000  5.6.5 Plagioclase Only two plagioclase grains (8 and 15 µm) are recovered from the Wawa diamonds. One is pure albite (Table 5.3), another is anorthite (An)-rich (Fig. 5.13). Albite is found with olivine and orthopyroxene, whereas An-rich plagioclase is found with clinopyroxene.  Fig. 5.13. EDX spectrum of a mineral inclusion identified as anorthitic plagioclase.  104  6. Origin of diamonds from the Wawa calc-alkaline lamprophyre 6.1 Tracing the diamond source(s) The heterogeneity displayed by Wawa diamonds in their crystal habits, N content, aggregation of N defects, inclusion parageneses, and isotopic signatures points towards multiple sources for this diamond suite. In the following section, the results from the present study are discussed and compared with literature data to shed light on the origin of diamonds brought to the surface by calc-alkaline lamprophyres at Wawa.  6.1.1 Diamond morphology The population of diamonds studied by Lefebvre (2004) displays different crystal habits, from octahedral to cubo-octahedral single crystals to fine and coarse aggregates, aggregates and twins being much more abundant than single crystals. The vast majority of the studied samples (51 out of 80) consists of poorly resorbed octahedra and octahedral aggregates, with a degree of resorption ranging from 4 to 6 in the classification proposed by McCallum (1994). Single crystal cubic diamonds are less than 10% of the population. Diamonds from the Wawa area studied by Stachel et al (2006) show somewhat similar morphological aspects in the Cristal locality, with a population dominated by low resorption octahedral crystals, although the percentages of twins and aggregates (20 and 2% respectively) are considerably lower than the ones observed by Lefebvre (2004). Diamonds from the other locality (Genesis) included in Stachel et al.’s study (2006) are very distinct, their population being dominated by cubes, with 5% resorbed dodecahedra and 10% of diamonds with irregular morphology. It is interesting to note that, stratigraphically, the unit from which the diamonds studied by Lefebvre et al. (2004) and in this project were collected, is situated in between the  105  (older) Cristal unit and the (younger) Genesis unit from which Stachel et al.’s samples were taken. Similar relative abundances of crystal habits to the ones observed by Lefebvre (2004) in diamonds from Wawa are found in other localities worldwide. Diamond populations from the Orapa, Lethlakane and Jwaneng mines in Botswana are also characterized by high occurrence of aggregates and macles, and by the presence of cubic and cubo-octahedral habits among diamonds < 2mm (Harris, 1987; Otter et al., 1994; Deines et al., 1993). Similar percentages of cubic and cubo-octahedral crystals as seen in Wawa (~5%, Lefebvre, 2004) have been documented at pipe DO-27 in the Slave craton (Davies et al., 2004), and at Sloan kimberlites, Colorado/Wyoming (Otter at al., 1994). Low percentages of cubic crystals (<5%) are known in Zaire (Boyd et al., 1987), in Venezuela (Guaniamo placer deposits, Kaminsky et al., 2000) and in biotite gneisses from UHP massifs (Cartigny at al., 2001, and references therein). Thus, the morphology of the Wawa diamonds we studied does not support the notion that diamonds formed in orogenic settings have, in general, higher chances to display cubic crystal habits. In contrast to the above evidence, De Corte et al. (1999) reported that the population of diamonds from the Kotchetav UHP massif is dominated by cubic and cuboctahedral morphologies. One of the populations of diamonds from the Wawa area (Genesis) studied by Stachel et al. (2006) also showed a vast predominance of cubic crystal habits over octahedral. We conclude that among suites of orogenic diamonds, it may be possible to come across a suite of diamonds with relatively high proportions of cubic stones. The presence of different crystal habits within the same diamond suite, as seen in our Wawa diamonds, may suggest that the host rock has sampled various sources on its way to the surface.  106  The studied Wawa diamonds contain an unusually high proportion (26%) of aggregates and macles, although the two groups, taken individually do not account for more than 10% of the whole population. Similar proportions of aggregates have been observed in the Slave Craton (Gurney et al., 2004) and in Brazil (Hayman et al., 2005). The formation of aggregates and twins (such as macles) is due to crystallization at numerous nucleation sites unstable, carbon supersaturated conditions (Harris and Gurney, 1979; Sunagawa, 1984; Otter et al., 1994; Deines et al., 1993). Single crystals may develop a cubic habit under similar growth conditions as aggregates and twins, but under slightly higher carbon supersaturation (Sunagawa, 1984). Single octahedral crystals, which are the most common in most diamond suites worldwide, are formed through a slower crystallization process under stable growth conditions of low carbon saturation (Sunagawa, 1984).  6.1.2 Cathodoluminescence and fluorescence  The cathodoluminescence colours displayed by the majority of Wawa diamonds (orange, yellow and green) are very unusual. Most natural diamonds cathodoluminesce blue (Bulanova 1995); red CL colours are only noted for irradiated natural diamonds (Milledge et al. 1999; Zaitsev 2001) and for N-doped non-annealed diamonds grown by the Carbon Vapor Deposition (CVD) process (Martineau et al. 2004). CL spectroscopy allows a comparison between the studied Wawa diamonds and diamonds with visibly similar cathodoluminescence. Most blue CL natural diamonds show a broad luminescence band at 400-490 nm (Lindblom et al. 2003) or several peaks in these wavelengths (Fig. 6.6). The most common of these CL features are a peak at ~415 nm linked to 3 nitrogen atoms with a vacancy (N3 center) in diamonds with a highly aggregated N, and an A-band (415-443 nm) in N-poor diamonds  107  (Zaitsev 2001). In contrast, CL colours of Wawa diamonds are controlled by emission at longer wavelengths above 500 nm, although the A-band is present as a subordinate peak (Fig. 6.6). The A-band observed at ~430-442 nm in Wawa diamonds with yellow and red CL is common in natural and artificial diamonds grown by CVD and High Pressure High Temperature (HPHT) processes (e.g. Paczner et al. 2000). The A-band has been associated with structural defects such as dislocations (Graham and Ravi 1992; Marinelli et al. 1996, Iakubovskii and Adriaenssens 1999) and to sp2 defects in the network of sp3 (Takeuchi et al. 2001). Several authors state that the A-band is especially strong in low nitrogen diamonds (Lang 1977; Hanley et al.1977; Zaitsev 2001). According to Hanley et al (1977), the A-band is the main CL feature of type IIa diamonds. This is supported by our data, as the band is observable only on diamonds with N content below 70 ppm. The origin of the broad band occurring around 520 nm in all Wawa diamonds is uncertain (Iakoubovskii and Adrianssens 1999). This "green" band is quite common in natural diamonds, and intensity and excitation photon energy dependencies of luminescence measured for CVD and shock-synthesis diamonds suggest the band is related to boron (Collins et al. 1992; Iakoubovskii and Adrianssens 1999). The band can also be produced in CVD diamond films by H-plasma treatment (Hayashi et al. 1996). Bands at around 520 nm have been found associated with some exotic elements in diamonds (Zaitsev 2001), as well as with hydrogen (Yang et al. 1995). The broad "green" band is detected in some samples of carbonado, a black cryptocrystalline diamond. Here, the band is ascribed to the sharp 525 nm doublet observable in the photoluminescence spectrum. The authors could not correlate this doublet with any known diamond bands (Magee and Taylor 1999).  108  The sharp line at 575.5 nm observed in most Wawa diamonds is the CL emission of the neutrally charged defect (so-called N-Vo center) consisting of a vacancy trapped adjacent to an isolated nitrogen (Zaitsev 2001). It is found in all types of natural and synthetic diamonds, and the intensity of the peak in Type IaB diamonds is proportional to the concentration of the 4coordinated nitrogen (Zaitsev 2001). The N-Vo center can be produced by plastic deformation and by γ-irradiation in type I diamonds (Zaitsev 2001). The peak anneals significantly at high pressure- high temperature (HPHT) treatment (Martineau et al. 2004) at T>1400o (Zaitsev 2001). The 575 nm CL peak is often present in carbonado diamonds (Milledge et al. 1999; Magee and Taylor 1999) and was reproduced by irradiation in polycrystalline centered diamonds (Zaitsev 2001), the analogue to natural carbonado. The red (Milledge et al. 1999), yellow and orange (Magee and Taylor 1999) CL colors in carbonados are mapped as concentric haloes around radioactively damaged spots, further supporting the irradiation origin of the 575 nm peak. Deconvolution of CL spectra of Wawa diamonds returns numerous peaks between 578 and 622 nm. At least one of these peaks must be a broad band at 550-580 nm observed in N-bearing natural diamonds and related to B' platelets (Zaitsev 2001). In addition to the B' platelet band, the red CL emission could be controlled by many common CL bands, such as 1) the "red band" (578 nm) observed in natural brown diamonds and related to a vacancy; 2) peaks at 585 and 598 nm observed in annealed oxygen-implanted diamonds and ascribed to an O-containing defect; 3) the 603 nm peak reported for synthetic diamonds with the 4-coordinated nitrogen; 4). Peaks at 616 and 602 nm found in annealed carbon-implanted low-N diamonds and related to intrinsic interstitial-type defects (Zaitsev 2001). The deconvoluted peaks between 578 and 620 nm are unlikely to contain the 596/597 nm doublet observed in photoluminescence spectra of CVD diamonds with single substitutional N. In Wawa samples, there is no correlation between the  109  intensity of these deconvoluted peaks and the content of single N atoms estimated through FTIR. Moreover, the 596/597 nm peaks are not reported in any diamonds that remained long at high temperatures, i.e. in natural or HPHT diamonds (Martineau et al. 2004). Overall, the CL spectra of Wawa diamonds resemble most the CL spectra of carbonado with yellow and green CL (Magee and Taylor 1999); peaks at 520 and 575 nm are prominent in Wawa and carbonado samples. In Wawa diamonds, the CL emission is practically absent at wavelengths above 630 nm. In contrast, the CL emission in this region in the carbonado shows a plateau or a broad peak (Magee and Taylor 1999). The CL characteristics of the Wawa diamonds also differ from those of CVD diamonds with red CL. The N-doped non-annealed CVD diamond spectra do not show any CL peaks at wavelengths longer than 575 nm (Martineau et al. 2004). We conclude that the unusual cathodoluminescence colours in Wawa diamonds are unlikely to have a similar origin with other diamonds with red CL. The red CL emission in Wawa diamonds is more realistically interpreted as a result of defects on interstitial O or C, a vacancy or B' platelets. Whatever was the process that led to atypically defective lattices of the diamonds, it must be significantly different from common diamond-forming processes. Recent studies (Bruce et al., in press) have linked long wavelength cathodoluminescence in diamonds to metamorphism, based on the occurrence of orange and red cathodoluminescence in HPHT (high pressure – high temperature) treated diamonds (Deljanin & Simic 2007). However, the conditions of pressure and temperature experienced by the metamorphosed host rocks of Wawa diamonds (2-3 kb and 325°-450°C, greenschists facies) are much less extreme than the ones experienced by diamonds originated in cratonic settings during their mantle residence (Bruce et al., in press). It is worth noticing that the virtual absence of a CL “blue” band at 415 nm, which always accompanies the 503 in natural diamonds from unmetamorphosed rocks, has also been  110  reported in metamorphic diamonds from the Kotchetav massif (Iancu et al., 2008). According to Bruce et al. (in press) the influence of metamorphism on diamond cathodoluminescence is correlated with the duration of the P-T increase, the specific P-T path, and the stress or fluid regime of metamorphism. On the other hand, the fluorescence colours displayed by Wawa diamonds do not differ substantially from the colours observed in diamonds from other locations worldwide (e.g. Hayman, 2005). Both blue and yellow fluorescence are typical of diamonds with aggregated nitrogen defects (Bulanova, 1995). No evident correlation has been found between morphology, colour, resorption, cathodoluminescence colours, fluorescence colours and nitrogen contents or aggregation state in Wawa diamonds (Lefebvre, 2004). 6.1.3 Nitrogen content and aggregation state The characteristics of nitrogen content and aggregation of nitrogen defects observed in Wawa diamonds are similar to what has been reported on many peridotitic and eclogitic suites worldwide (e.g. Deines et al., 1989; Stachel and Harris, 1997), but noticeably different from the ones in ultra-deep diamonds, the latter having lower N contents and higher aggregation than is seen in Wawa (Hayman, 2005). As pointed out in section 6.4, Wawa diamonds studied by Lefebvre (2004) are characterized by relatively low nitrogen concentrations (<300 ppm) and variable nitrogen aggregations (0-95% nitrogen in B form) with two modes 10-30% and 60-100% B (Fig. 6.10), suggesting that at least two different populations are present in this suite. The heterogeneity in the N characteristics of diamonds sampled from the same location, which we showed in the previous chapter (Fig. 6.7, 6.9, 6.10), could be an indication that the Wawa lamprophyres brought to surface diamonds from different sources.  111  The study of Stachel et al. (2006) on diamonds from two localities of the Wawa area (Cristal and Genesis) showed indeed the presence of two distinct populations both in terms of morphology and nitrogen characteristics. The Cristal diamonds are mostly octahedral and characterized by low Nitrogen contents (0-150 ppm), with extreme variability in the aggregation of nitrogen defects (0-97% of B aggregates); the Genesis diamonds, instead, have prevalently cubic habits and higher N contents (typically between 200 and 400 ppm), with poorly aggregated nitrogen defects (0-10% of B aggregates, mostly Type IaA). This somewhat matches the findings of Lefebvre (2004) and this study, in that cubic diamonds from Wawa show, on average, higher N contents and less aggregated N defects with respect to octahedral diamonds. N systematics of a diamond suite is controlled by the mantle residence time and its temperature (Evans and Harris, 1989; Taylor et al., 1990; Mainwood, 1994; Mendelssohn and Milledge, 1995). Plastic deformation is also known to enhance nitrogen aggregation states in diamond (Griffin et al, 2000; Davies et al., 2003). However, plastic deformation, in the form of lamination lines and brown coloration, has been observed only in few diamonds from Wawa, therefore the state of aggregation of nitrogen defects in their crystal lattice is mainly controlled by mantle residence time or temperature rather than of plastic deformation itself.  6.1.4 Residence time in the mantle. As pointed out in the previous section, the presence of diamonds with similar N contents but varying percentages of B aggregates (Fig. 5.11A) is evidence that diamonds from Wawa cannot have formed at a single temperature, as they do not follow a single isotherm. Considering a maximum mantle residence time of 1.8 Ga (based on the age of the Earth, ~4.5 Ga), storage temperature would have to be greater than 1050 oC (Fig. 6.8A). Stachel et al. (2006), based on the N aggregation in diamonds from the Cristal and Genesis locations, proposed a residence time  112  for Wawa lamprophyric diamonds 0.3-0.8 Ma. Considering this shorter mantle residence time of 0.8 Ga, storage temperature would be greater than 1150 oC (Fig. 5.11A). The fact that many of the Type IaAB diamonds studied by Lefebvre (2004) show platelet degradation (Fig. 5.11B) suggests the presence of a subpopulation which underwent annealing at high temperatures (Woods, 1986, Taylor et al., 1990, Clark, 1992). This would be supported also by the presence of Type IIa diamonds, which can be interpreted either as diamonds formed in a low nitrogen environment (Davies et al., 1999) or as annealed Type Ia diamonds which resided in the mantle at high temperatures long enough to experience loss of N by diffusion(Watson 1996; Davies et al., 1999). However, as shown by Shiryaev (2006) the effect of diffusion of elements in the diamond crystal lattice is very limited.  6.1.5 Stable isotopes 15  13  Wawa diamonds by combined δ N - δ C values resemble peridotitic diamonds from other localities worldwide, whereas little to no overlap occurs with the fields of eclogitic, UHP (called metamorphic in Fig. 6.1 and 6.2) and fibrous diamonds 15  (Fig. 6.1). Positive δ N values are a relatively common feature 15  13  Fig. 6.1. δ N versus δ C plot showing the isotopic composition of diamonds on which the combined study was conducted. Number of analyses=13. Fields from diamonds worldwide are shown for 15 comparison. Grey bands indicate the typical mantle values for . δ N 13 and δ C (e.g. Cartigny et al., 1998).  113  of peridotitic diamonds (Fig. 6.3), yet, on average, Wawa diamonds  15  tend to have slightly higher values of δ N with respect to other peridotitic diamond suites (Fig. 6.2 and 6.3). This difference can be explained through the involvement of metasomatism. It has been shown that metasomatised peridotitic 15  xenoliths have higher δ N values (up to +12‰) than the unmetasomatised peridotitic mantle (5‰) (Yokochi et al., 2009). These authors also found that metasomatism can bring about severe diffusive isotopic fractionation between minerals (olivine, pyroxenes and phlogopite) of the same xenolith. The magnitude of this fractionation can reach values of 24‰. (Yokochi et al., 2009). Sixty samples out of the 61 studied display 13  δ C values that are close to -5‰, the value now universally accepted as typical of mantle derived carbon (e.g. Cartigny et al., 1998, and references therein). The mean of -2‰ shows that these 13  diamonds are slightly enriched in C with respect to the average mantle value. However, one sample shows a light isotopic composition Fig. 6.2. Histograms showing the N isotopic compositions of diamonds from Wawa compared with subduction related metasediments and diamonds worldwide, and their relative abundances (modified from Cartigny, 2005).  13  (δ C=-26.2‰) similar to the average value of organic matter in marine sediments (~-25‰, e.g.  114  Cartigny et al., 1998). This seems to suggest the presence of more than one source of carbon for this diamond suite. 13  Very similar δ C have been reported by Stachel et al. (2006) for diamonds of the Wawa area. Diamonds from the Cristal location, which are characterized mostly by octahedral 13  morphologies, display a mean δ C of -3.2‰, a slightly higher value than observed in peridotitic diamonds worldwide (~-5‰). Stachel et al. (2006) suggested that this isotopic shift from mantle value could indicated either crystallization from a mixed fluid/melt containing a isotopically heavy component derived from subducted inorganic carbon, or the presence of a carbon isotopic heterogeneity beneath the Southern Superior Craton during the Archean. On the other hand, diamonds from the Genesis locations studied by Stachel et al. (2006), which are characterized by 13  mostly cubic crystal habits, display typical mantle δ C values, with a mean of -4.7‰. The two 13  cubic diamonds analyzed in the present study also show mantle like δ C values (-4.4 and -3‰). 13  In contrast to mantle δ C signatures, N isotopic data point towards a crustal origin of Wawa diamonds. Most of the Wawa diamonds that were analyzed for their N isotopic composition (10 15  out of 13) yielded positive δ N values, which resemble those of subduction related metasediments and metamorphic diamonds found in UHP terrains (Fig. 6.1 and 6.2). Nitrogen isotopic ratios of marine sediments associated with subduction processes are positive (~+5‰) (Peters et al., 1978; Haendel et al., 1986; Bebut and Fogel, 1992; Boyd et al., 1993) and a trend 15  of increasing δ N, and decreasing N content, with increasing metamorphism is observed 15  (Haendel et al., 1986). The expected δ N value in the mantle is -5‰ (Cartigny et al., 1998, and references therein).  It is possible that Wawa diamonds were formed through recycling of  sediments in a subduction zone, i.e. subduction of C-bearing sediments and ensuing  115  metamorphism. According to the model of Javoy (1984, 1986), in the Earth’s early history the 15  15  mantle’s δ N evolved from an initial value lower than -25‰, to the present δ N of -5‰. This 15  evolution requires large recycling of crustal nitrogen (with δ N ~ 0‰, derived from the atmosphere) into the mantle. The fact that diamonds as old as 3.3 Ga like those at Finsch and 15  Kimberley Pool (Richardson et al., 1984) display δ N values of -5‰ suggests that the recycling had been more efficient in the Archean, despite the absence of biotic activity. The fixation of atmospheric nitrogen (N2→NH4+) in crustal sediments would have been possible due to the reducing atmosphere in the Archean, which would favour the solubility of N (Cartigny et 15  al.,1998). Metamorphism in subduction zones would then cause the δ N of recycled sediments to increase towards positive values (Haendel et al., 1986). 15  An alternative explanation to the recycled origin of positive δ N values in Wawa diamonds is isotopic fractionation of nitrogen in the mantle, between mantle minerals and a metasomatic 15  fluid of mantle origin with an initial δ N of -5‰ (Cartigny et al., 2004). However, if this process 15  had been active, it would have produced a negative correlation between δ N and total N content in diamonds (Cartigny et al., 2001). Since we do not observe this correlation in our Wawa samples (Fig. 6.3), we reject fractionation as viable explanation. The model that satisfactory explains the origin of Wawa diamonds should incorporate and reconcile N and C isotopic data. The hypothesis that Wawa diamonds were formed through 13  recycling of sediments is not supported by C isotopic data, as only one sample has shown a δ C similar to the values of sediments. The hypothesis that Wawa diamonds were formed from mantle material is not supported by N isotopic data. As Fig. 6.3 shows, a mixing between a crustal and a mantle source of C and N is not a viable hypothesis, as the C isotopic signatures  116  and the N contents observed in Wawa diamonds do not fall along a trend between these two end members. The way to reconcile N and C isotopic data is a model involving the combined effect of early recycling of inorganic N and C into the mantle and isotopic fractionation induced by metasomatism. The isotopic composition of inorganic sediments subducted in the Archean would be ~ 5‰ 15  13  for δ N, and ~0‰ for δ C. These sediments would be flushed by metasomatic fluids with 15  13  typical mantle values of δ N and δ C, i.e. -5‰ and -5‰. Since N is much less abundant than C in the mantle (e.g. Cartigny et al., 1998) the amount of N in the fluid would be much smaller than the amount of C, hence the ratio of sedimentary N/ fluid N would be higher than the sedimentary C/ fluid C ratio. The result of the metasomatism with such low-N, high-C fluids would be the rapid change in the N isotopic composition and a relatively slow change in the C isotopic composition. Cartigny et al., 1998 refers to this as to the “reservoir effect”. As a result, 13  the minerals precipitating from such fluid would be characterized by mantle δ C values, but 15  sedimentary δ N values. This could account for the apparent discrepancy between the N and C isotopic results. A supporting evidence for this model is the wide occurrence of metasomatism in the mantle and the active participation of metasomatism in diamond-forming processes (e.g. Taylor et al. 1998; Stachel et al. 2004).  117  13  15  Fig. 6.3. δ C vs N content and δ N vs N content plots for Wawa diamonds. Number of analyses=44, for the upper plot; 13 for the lower one. Dashed curve indicates the “limit sector” where ~90% of worldwide diamonds fall (Cartigny, 2001). Dotted line indicates a mixing trend between a hypothetical crustal end member (grey box) and a mantle end member (pink box)  6.1.6 Diamond paragenesis The Wawa diamonds host primary inclusions of peridotitic (P) and eclogitic (E) paragenesis. Olivine and orthopyroxene are peridotitic in origin, clinopyroxene must be eclogitic, whereas plagioclases and sulfide are compatible with either of these assemblages. The studied diamonds are strikingly out of equilibrium with their primary mineral inclusions. Inclusions of peridotic and eclogitic affinities are found together in 4 diamonds (40% of the diamonds where inclusions  118  are studied), whereas in most diamond inclusion studies, mixed paragenesis is "the exception rather than the rule" (Gurney, 1989). The rest of the diamonds contain peridotitic (4 diamonds, 40%), eclogitic (1, 10%) or an indeterminate paragenesis (1, 10%) which may be either peridotitic or eclogitic. Moreover, all P- or E-type Wawa diamonds contain a low-pressure phase (plagioclase), incompatible with the diamond stability field. Thus, the majority (80%) of the diamonds shows either gross compositional disequilibrium, combining peridotitic and eclogitic minerals, or thermodynamic disequilibrium, combining shallow and deep minerals. The unequilibrated assemblages of inclusions defy a simple explanation. Two petrogenetic models which we propose for these diamonds are: (1) an atypically complex growth history of diamonds, or (2) an atypically pervasive alteration of primary inclusions through now annealed fractures in diamonds. A subduction setting is crucial for the first model. The diamonds must have grown in the mantle and in crustal portions of the slab, as evidenced by their occurrence in the peridotitic and eclogitic assemblages. The P-T stability field of eclogite in the slab is compatible with the depths and temperatures where the slab is diamondiferous (Fig. 6.4). The plagioclase found in the diamonds may be a relic, inherited from the prior existence of the oceanic lithosphere at shallower depths where it is made of plagioclase peridotite or mafic granulite. A repeated observation in HP/UHP terranes which that have been subducted and then obducted is that significant rock volumes may escape mineral equilibration at the prevailing P-T conditions, despite T as high as 650-750oC for UHP rocks (Chopin 2003). High rates of Archean subduction (Staudigel and King 1992) and equally rapid obduction of UHP terranes (Rubatto and Hermann 2001) make these blocks ideal for preservation of metastable assemblages. Moreover, plagioclase is known to coexist with diamond in UHP terranes (e.g. Shertl and Okay 1994;  119  Stockhert et al. 2001). The coexistence of eclogitic and peridotitic minerals within single diamonds (as reviewed in Gurney 1989; Schulze et al. 2004) and in a single xenolith (Sobolev et al. 1997) is not unknown, although it has not been previously reported on the same scale of  Fig. 6.4. Pressure-Temperature diagram illustrating different thermal regimes, solidi and mineral stability fields of peridotite and eclogite. Transient geotherms 1-4 are estimated temperatures in subducted slabs: 1 - old and fast (9 cm/y) subduction zone in NE Japan arc (Stern, 2002); 2 - modelled minimum temperatures in the 40 km thick slab subducting below the 67 km thick fixed plate with a convergence rate of 50 km per million years (Eberle et al. 2002); 3 - model T profile along the top of the slab with 30o dip, 10 cm/y subduction rate, 100 km thickness of the slab, and 60 km thickness of the overriding plate (England and Wilkins, 2004); 4 - young and slow (4.5 cm/y) subduction zone in SW Japan arc (Stern 1992). Stippled fields in geotherms 1 and 4 encompass all possible slab temperatures between tops and bottoms of the slabs. The "Flood basalt" geotherm is based on a typical heat flow of 97 mW/m2 in areas of Cenozoic igneous activity (Pollack et al., 1993). The "Back-arc" geotherm is based on a regional value of 120 mW/m2 in a modern back arc Tyrrhenian Sea with an active tholeiitic and calc-alkaline magmatism (Zito et al. 2003). The cratonic geotherm is a 40 mW/m2 model continental geotherm of Pollack and Chapman (1977). Anhydrous and H2O-saturated eclogite solidi and P-T conditions of the eclogite metamorphic facies (grey field) are from Stern (1992). Anhydrous and H2O-saturated peridotite solidi and depth facies of peridotite (plagioclase, spinel and garnet) are from Ulmer (2001). Graphite-diamond equilibrium is from Kennedy & Kennedy (1976).  120  occurrence as we observe in the Wawa suite. The bulk compositional disequilibrium can be explained by fine-scale mixing of metamorphosed crustal and mantle material of the subducted slab during upward advection in a "cold plume". This phenomenon, inherent to convergent margins, has been recently modelled by Gerya and Yuen (2003) who demonstrate the feasibility for upwellings of material 300-400oC colder than the ambient mantle, which emanates from the top surface of the descending lithosphere, and passes through the mantle wedge with ascension rates of approximately 10’s of cm per year. The second model suggests that compositions of the inclusions are not representative of the initial compositions of minerals syngenetic with diamonds, but rather are pseudomorphs. The atypical alteration of apparently intact minerals, from fresh well-faceted grains, all enclosed by an apparently non-fractured diamond, may be related to the attributes of the host Wawa volcanics. The volcanics are older that most diamondiferous primary rocks, and have also been metamorphosed and deformed by a major orogenic event. Both of these traits increase the potential for the diamonds to be fractured and annealed, and also brings the diamonds into contact with hydrothermal and metamorphic fluids. Evidence for late penetration of hydrous fluids rich in K, Na, Fe, Al and Si is found in the presence of abundant chlorite, biotite, apatite, various silicates rich in Al, Ca and Na, K-feldspar and K sulfides in cracks in the diamonds (Table 1). Most of these minerals can be related to host diamondiferous rocks, i.e. either be the lamprophyric phenocrysts, or a part of the greenschist assemblage. Clinopyroxene, biotite, plagioclase (Ab89) and hornblende are considered to be primary phenocrysts of the Wawa host-rock magmas, whereas chlorite, actinolite, albite and metamorphic biotite comprise the ensuing greenschist assemblage (Lefebvre et al. 2005). Djerfisherite is known to occur in lamprophyres (Rock 1991). Strontium-free apatite, phlogopite  121  and biotite, two compositionally distinct generations of clinopyroxene, potassic feldspar (Ort97 to Ab98), plagioclase (An50 to An6) and olivine (now completely altered), along with other minerals, have been documented as having crystallized from Archean lamprophyres of Abitibi (Wyman and Kerrich 1993). The late clinopyroxene in some Abitibi locations is enriched in Fe, whereas in others it is depleted in Ca, dropping its content from 22 to 13 wt% CaO, reminiscent of subcalcic clinopyroxene in Wawa diamonds. Micas also show Fe enrichment from phlogopite cores to biotite rims. Anorthite-rich plagioclase crystallized early, followed by the groundmass potassic feldspar, which is replaced by albite. Albitization of groundmass feldspars, involving loss in K2O and gain in Na2O, is the most prevalent form of alteration in Abitibi lamprophyres. All pseudomorphic replacements and changes in mineral compositions were ascribed by the authors to magmatic or deuteric processes in these unmetamorphosed lamprophyric rocks (Wyman and Kerrich 1993). Similar mineralogy is noted for diamondiferous and barren Archean lamprophyre dykes of Wawa located to the northwest of our study area (Williams 2002). If syngenetic inclusions were altered by the fluids related to the lamprophyres, then the fluids must be Fe-, Na- and Si-rich, causing formation of Fe- and Na-rich omphacite, albite and plagioclase. It is possible that the former paragenesis of syngenetic inclusions was peridotitic. Olivine and orthopyroxene remained intact, clinopyroxene was pseudomorphed to apparently eclogitic omphacite, with plagioclase being introduced into the diamonds metasomatically. Omphacite (although more jadeitic and more Fe-rich) is stable at low T and high water pressure (6-8 kb and 200-300oC) in association with chlorite, albite and other hydrous minerals (Deer 1997). Data on mineral inclusion parageneses in diamonds from the Cristal location provided by Stachel et al. (2006) seem to support the second model, as the entirety of the analyzed mineral  122  species are peridotitic. Moreover, Stachel et al. document the recovery of inclusions “consisting of a soft, whitish mass [which] represent alteration products of former syngenetic phases”, which probably bear a resemblance with the feldspars found in Wawa diamonds from the present study.  6.2 Possible scenarios of diamond formation Wawa diamonds are atypical of most worldwide diamond suites in many aspects. First, it is hosted by calc-alkaline lamprophyre rather than kimberlite or lamproite. Secondly, the host volcanic rock among the oldest diamondiferous rocks on Earth, and has experienced regional metamorphism and deformation. Finally, the diamonds show yellow-orange-red CL and contain mineral inclusions unequilibrated with each other and with host diamonds. How and where could such diamonds have formed? The studied suite of Wawa diamonds is unlikely to have crystallized from the host lamprophyres. The following characteristics of the Wawa diamonds are incompatible with those of phenocrystal origin: 1) The presence of non-uniformly resorbed and etched diamonds; 2) The low proportion of fibrous cubic diamonds; 3) The presence of distorted diamonds shapes; 4) The high nitrogen aggregation state (>50% B-centers) indicative of long mantle residence times or high mantle residence temperatures. Based on this evidence, a xenocrystal origin is preferred for the Wawa diamonds.  6.2.1 A case for cratonic origin of Wawa diamonds The studied suite of diamonds may be xenocrystal cratonic. They may have formed in the pre-2.7 Ga continental mantle below the MGB (Thurston 2002; Sage et al. 1996a; Sage et al. 1996b). At ~2.7 Ga, the craton rifted and saw development of a flood basalt province with voluminous komatiite-basalt-rhyolite volcanism (Sage et al. 1996a). Diamondiferous  123  lamprophyres are coeval with the late bimodal cycle of the volcanism. Quasi-contemporaneous Kenoran orogeny merged the rifted blocks of the craton (Thurston 2002). An autochthonous origin for the MGB implies coupling of the crustal and mantle blocks and significant heating of the mantle associated with rifting and formation of flood basalts. Cratonic xenocrystal origin explains many characteristics of the diamonds, such as 1) The predominance of aggregates; 2) The absence of skeletal and re-entrant diamonds; 3) The presence of highly and non-uniformly resorbed, and etched diamonds; 4) Low nitrogen contents; 5) The presence of undeformed diamonds with highly aggregated nitrogen which formed at high ambient mantle temperatures; 6) the predominance of peridotitic mineral inclusions; 7) the C isotopic signature of almost all of the studied samples. The temperatures for the majority of the Wawa regular diamonds are estimated to be as high as 1050-1150oC, in order to achieve the observed N aggregation state under the assumption that the diamonds resided in the mantle for up to 1.8 Ga. If we assume the residence time of 0.8 Ma, then the temperatures would be even higher (1100-1200 oC). These temperatures exist at depths greater than 160 km in the cold cratonic mantle (Fig. 6.4). If the more realistic shorter residence time is assumed, the mantle temperatures must be higher and the diamonds must have resided at a greater depth. In the cratonic model, disequilibrium assemblages of inclusions and atypical CL colours of diamonds would be ascribed to effects of late metasomatic and metamorphic processes. A cratonic origin for one of the other diamond suites found in the Wawa area (Cristal location) is advocated by Stachel et al. (2006). Such an origin is suggested by great (at least 250 km) depths of diamond formation, which, in turn, are indicated by inclusions of majorite and high (~1250oC) temperatures of nitrogen aggregation.  124  Many features of Wawa diamonds and the tectonic setting of the host lamprophyres are, however, inconsistent with the cratonic origin. Two major problems arise because of thermodynamic incompatibity between Wawa diamonds and their lamprophyric host rocks. They simultaneously require a cold mantle for the diamond preservation and a hot mantle to produce the 2.7 Ga voluminous volcanics of Cycle 3 of the Michipicoten greenstone belt. Active flood basalt provinces have high heat flow that implies shallow melting incompatible with the presence of diamonds (Fig. 6.4). Hot upwelling asthenosphere in these tectonic settings would destroy diamondiferous mantle roots of the continents (Helmsteadt 1994) and pre-2.7 Ga diamonds are unlikely to survive subsequent rifting and magmatism. However, Lehmann et al. (2010) recently reported the occurrence of diamondiferous kimberlites coeval with the Deccan flood basalts at ~65 Ma. The combination of Wawa diamonds and Wawa lamprophyres is also incompatible with respect to their formation depths. It was shown that Wawa lamprophyric magmas formed at 3050 km depths, much shallower than the diamond stability field (Fig. 6.4). The relatively low Ti/Y ratio (<500) of the lamprophyres can be in equilibrium only with spinel peridotite, whereas deeper-seated kimberlite and lamproite magmas equilibrate in the garnet facies and have Ti/Y ratio >500 (Williams 2002). Thus, diamonds cannot be entrained by Wawa lamprophyric magmas on their ascent to the surface in the cratonic mantle. Furthermore, a simple xenocrystal cratonic origin of Wawa diamonds would be incompatible with the results obtained from the analyses of N stable isotopes, as the isotopic signature displayed by most analyzed samples shows an affinity with sedimentary crustal materials, and hence indicates that the source of N is not located in the mantle (Fig. 6.2). As pointed out in section 6.1.4, it is possible that N and C were recycled in the mantle at an early stage through subduction of marine sediments. Diamonds would have been formed in a later  125  metasomatic event, triggered by a mantle fluid of melt characterized by typical mantle N and C isotopic signatures (-5‰ of both δ13C and δ15N), and that would account for the isotopic signatures of Wawa diamonds. Stachel et al. (2006), based on the evidence of high-Cr harzburgitic inclusion parageneses observed in diamonds from the Cristal location, favor a xenocrystal cratonic origin for diamonds in the Wawa area. According to these authors, the characteristics of Wawa diamonds prove the existence of a thick depleted lithosphere package already before the complete stabilization of the Superior Craton during the Kenoran Orogeny.  6.2.2 A case for orogenic origin of Wawa diamonds The alternative origin of the suite as orogenic xenocrystal diamonds is also possible. Wawa diamonds have the following characteristics common to orogenic diamonds: 1). A crystal size distribution significantly skewed towards microdiamonds; 2). The weak resorption (Class 4 and 5) of the majority of diamonds; 3) An association with plagioclase and assemblages with metastable phases; 4) diamonds showing positive values of δ15N, similar to the ones of organic sediments and of UHP (metamorphic) diamonds. Eleven of the 13 samples analyzed for their N isotopic composition do show affinity with crustal materials and with subduction-related metamorphic diamonds (Fig. 6.2). However, diamonds originated in this environment should display negative values of δ13C between -10 and -30‰ (e.g. De Corte et al., 1999) if their source was organic, or positive values around 4‰ if the source was crustal inorganic carbon (Cartigny, 1998) and that is not the case, for our Wawa diamonds. A lot of evidence indicates a convergent margin environment for the magmagenesis of the Wawa diamondiferous lamprophyres, as reviewed in the introduction. Under this scenario, the  126  lamprophyres formed contemporaneously with and somewhat later than Cycle 3 volcanic rocks of the Michipicoten greenstone belt. This is consistent with tectonic and petrologic studies, which find that these rocks were produced in a convergent margin setting as a result of subduction and accretion of the Wawa subprovince to the Superior Craton nucleus (Sage 1994 and references therein; Arias 1996). Further supporting evidence for a subduction origin for the Wawa lamprophyres is their strong negative Nb-Ta, Ti and Zr-Hf anomalies (Williams 2002). Within the convergent margin setting, the subducted slab remains the only cold block favorable for diamond crystallization and storage. Mantle segments below other terranes of the convergent margin such as the back-arc, or the mantle wedge (T~ 1400oC) are too hot to contain diamonds (Fig. 6.4). In the slab, on the contrary, diamond is stable at even shallower depths than those usually associated with diamonds from cratonic settings. Diamond in the subducting slabs can form at 100 to 130 km depths, depending on subduction parameters and primarily on the rate of subduction (Fig. 6.4). If ultrafast subduction prevailed in the early history of Earth (Staudigel and King 1992), the diamonds could begin crystallizing at even shallower depths (<100 km). The depths of diamond formation may thus correspond to depths of the lamprophyre generation in the mantle wedge. Alternatively, the paradox of shallow Wawa lamprophyres and deep diamonds can be reconciled with a help of "cold plumes" (Gerya and Yuen 2003). The diamonds, in a complex mixture of different compositional blocks, could be carried up by fast "cold" plumes before plucked up by lamprophyres. In this scenario, the metasomatic process described in section 6.1.4, involving recycling of a crustal C and N source and a later interaction with a mantle-derived metasomatic fluid is clearly the most viable hypothesis to explain the isotopic signatures of Wawa diamonds.  127  A major failure of the orogenic model is its inability to explain the presence of undeformed diamonds with highly aggregated nitrogen, formed at high ambient mantle temperatures. If we assume that the convergent regime existed in Wawa from 2.9 to 2.7 Ga as manifested by the MGB volcanism, then the diamonds had to reside at T = 1140- 1390oC to produce an observed N aggregation state. These temperatures are unrealistically high for the subducting slab (Fig. 6.4), but achievable in the mantle wedge. However, if the subduction was episodic, the slab had to warm up between volcanic cycles, thus accounting for the possible higher average mantle residence temperatures. Some other physical and chemical properties of the diamonds (low N, the presence of highly and non-uniformly resorbed diamonds, the predominance of diamond aggregates and the absence of skeletal crystals, the mantle-like C isotopic signature) also do not agree with their possible orogenic origin. The fact that only 1 out of 44 Wawa diamonds analyzed for their C isotopic signature shows affinity with organic C (δ13C=-29‰) indicates that crustal material recycled via subduction cannot be the only source from which this diamond suite originated.  128  7. Concluding discussion 7.1 Characteristics of the diamondiferous mantle and processes of diamond formation. Diamonds have often been referred to in literature (e.g. Meyer, 1987) as “time capsules”, as their hardness and chemical inertness allows them in many cases to preserve information about the environment in which they crystallized. Both diamond suites considered in this study seem to have originated in the lithospheric mantle and their characteristics (morphology, N content and aggregation state, isotopic composition) did provide us with a wealth of information regarding the composition, the temperature and pressure of the mantle and the geological processes taking place in it, at the time of diamond formation. In this section we will summarize all the information collected in this study on the mantle in the cratonic setting and in the orogenic setting as well as what we inferred on the diamond forming processes that take place in both of these settings.  7.1.1 The cratonic setting  The diamondiferous mantle underneath the N Slave craton is mainly eclogitic in composition. As shown in section 3.5, all minerals extracted from our Jericho diamonds are either eclogitic or “websteritic” in composition. This evidence is corroborated by the fact that the diamondiferous xenoliths from the Jericho kimberlite are only eclogitic, in a population dominated by peridotites (75% of the total, Kopylova et al., 1999b). As we illustrate in Fig. 7.1., the formation and emplacement of eclogitic diamonds in the mantle below Jericho can be summarized as a four stages process. The first stage corresponds to the formation of eclogites through subduction at 1.88÷1.84 Ga (Fig. 7.1), as documented by seismic  129  Fig. 7.1. A. Formation of eclogites through subduction. B. First metasomatic even enriching eclogites in HFSE and leading to the formation of zircon and rutile. C. Second metasomatic event, where a fluid enriched in Ba, LREE and C causes the crystallization of apatite, phlogopite, and diamond. D. Entrainment of barren and diamondiferous xenoliths by the Jericho kimberlite melt, and ascent to the surface.  130  ((Bostock 1997; Cook et al. 1999)) and petrological (Heaman et al., 2006; Smart et al., 2009) data. The reconstruction of the mantle column made by Kopylova et al. (1999b) suggests that eclogites were present at depths ranging from 60 to 200 km (section 4.2). The composition of garnets and clinopyroxenes found in eclogitic xenoliths and included in diamonds indicates that the mantle below Jericho has been subject to melt extraction and to at least two main metasomatic episodes, one of which must have been responsible for the formation of diamonds. According to the geochronological studies conducted by Heaman et al. (2006) on barren eclogites from the Jericho Kimberlite, a first episode of metasomatism and melt extraction must have affected the eclogites between 1.78 and 1.44 Ga (Fig. 7.1 B). During this episode, eclogites were enriched in HFSE possibly by fluids derived from the subducted slab, leading to the formation of minerals such as zircon and rutile. The third stage, illustrated in Fig. 7.1C, is characterized by another episode of metasomatism and melt extraction, dated by Heaman et al. (2006) at 1.25÷0.98 Ga. We indicated this episode as the one responsible for diamond formation due to the similarity in composition between the minerals which crystallized in the eclogites during this event and the minerals included in diamonds (section 4.4.1 and 4.4.2). Mantle fluids enriched in Ba, LREE and isotopically “light” C (δ13C~-35‰) percolated through the mantle causing the formation of a new garnetclinopyroxene + phlogopite + apatite eclogitic paragenesis and the partial melting of the previous assemblage, with subsequent melt extraction. Diamonds must have crystallized during this process, as garnets and clinopyroxenes characterized by an enrichment in Ba, LREE and Mg are found both in diamondiferous eclogites and as inclusions in diamonds (see section 4.5). Geothermometry data from both diamond inclusions and their host eclogites showed that this metasomatic event was confined between 140 and 200 Km depth (section 4.5.2, Fig. 7.1C). The  131  fourth and final stage (Fig. 7.1D) consists in the entrainment of both barren and diamondiferous mantle xenoliths by the kimberlitic melt at 178±5 Ma (Heaman et al., 2006), which were then brought to surface. Quite likely, xenoliths were infiltrated by the host kimberlite magma during their ascent towards the surface, as minerals from barren eclogitic xenoliths are enriched in K and Mg with respect to minerals found as inclusions in diamonds (section 4.4).  7.1.2 The orogenic setting The study of a diamond suite recovered from Archean (2.7 Ga) calc-alkaline lamprophyres represents a unique opportunity to study both the Archean mantle and the processes that lead to the emplacement of such unusual diamondiferous rocks. Unfortunately, the small size and the scarcity of inclusion bearing stones did not allow us to draw a picture as clear as we did for the Jericho mantle, yet we were able to capture some intriguing features of the mantle below Wawa at the time of diamond formation. Several diamonds display mixed inclusions paragenesis, with peridotitic phases such as olivine and orthopyroxene associated with omphacitic clinopyroxene (of eclogitic affinity) and plagioclase (both albitic and anorthitic) (section 5.5). This clearly indicates that the environment where these diamonds were formed went through dramatic changes during a time period as short as the growth of a diamond crystal. Such changes could be the result of metasomatic events (section or, in alternative, the consequence of the rise of a diapiric structure (“cold plume”, Gerya and Yuen, 2003) from a cold subducted slab of crustal lithosphere through the overhanging mantle wedge. However, IR data on Nitrogen content and aggregation display, for many of the analyzed stones, low N concentrations and fully aggregated nitrogen defects, which are typical features of diamonds residing in a stable portion of subcratonic mantle for a long time. The isotopic  132  composition of N in Wawa diamonds, with positive values of δ 15N, suggests that the formation of diamonds in this portion of the mantle was possibly predated by events of recycling of crustal material through subduction. Since our results, combined with the results from other authors (Lefebvre, 2004, Stachel et al., 2006) seemed to point in two different directions we developed two models explaining the origin of diamonds from Wawa, which are summarised in the cartoons in Fig. 7.2 and 7.3. The first model is based on the subduction of suboceanic lithosphere into the mantle, causing the recycling of crustal C and N from marine sediments and the formation of diamonds (Fig. 7.2A,B). As diamonds were forming, cold material from the slab started rising towards shallower depths in diapiric structures (“cold plumes”, Gerya and Yuen, 2003). Such cold plumes are described as “3-D diapiric structures forming from thermal-chemical instabilities developed at a depth of around 100-200 km, as a result of the dehydration of serpentines and the subsequent hydration reactions involving peridotites”. Diamond-bearing portions of material brought up by cold plumes were then sampled by lamprophyric magmas, which managed to bring diamonds to the surface (Fig. 7.2C). Diamondiferous lamprophyres of Wawa were then caught in the Kenoran orogenic event, and underwent greenschist facies metamorphism (Fig 7.2D). The second model implies a cratonic origin for Wawa diamonds. In such a scenario, early Archean subduction processes would be responsible for recycling crustal C and N with into the mantle (Fig. 7.3A). The deep portions of this “cold”, subcratonic lithosphere where crustal C and N had been recycled through subduction were then subject to a metasomatic process induced by a C and N bearing mantle fluid (Fig. 7.3B). As in the previous model, this process was responsible for the formation of diamonds characterized by a “mantle” C isotopic signature (δ13C  133  Fig. 7.2. A cartoon showing stages of diamond formation in the orogenic model. A. Subduction of C and N bearing marine sediments. B. Formation of diamond at depth through mantle metasomatism. C “Cold plumes” rising from the subducted slab bringing diamonds to shallower depths where they are entrained by lamprophyres. D. Kenoran orogeny, causing the diamondiferous lamprophyres to undergo greenschist facies metamorphism.  134  Fig. 7.3. A cartoon showing stages of diamond formation in the cratonic model. A. Early Archean subduction and recycling of C and N. B. Formation of the pre-Superior craton and mantle metasomatism causing the formation of diamond. C. Mantle advection, bringing diamonds to shallower depths, and causing the rifting of the craton. D. Subduction and formation of lamprophyres that entrain diamonds, bringing them to surface. E Kenoran orogeny, causing the diamondiferous lamprophyres to undergo greenschist facies metamorphism.  135  ~ -5‰) and a “crustal” N isotopic signature (δ 15N>0) (see section 6.1.5). The main shortcoming of this model is that the only way to justify the entrainment of diamonds by lamprophyric magmas formed at a depth of 80 km (De Stefano et al., 2006; Scott Smith, 1996a, b) is by assuming an unprecedented “mantle advection” process bringing the lower, diamondiferous portions of the lithospheric mantle to shallower depths fast enough to prevent diamonds from turning to graphite (Fig. 7.3C). It is possible that this advection process is related to the continental rifting that preceded the Kenoran orogeny (Polat et al., 2009). At that point, diamonds would be entrained by lamprophyric magmas and brought all the way up to the surface (Fig. 7.3D), where the whole volcanic complex would then be involved in the Kenoran orogeny as is illustrated in the first model (Fig 7.3E).  7.3 Implications of this work for diamond and mantle petrology The data we collected on diamonds from Jericho and Wawa and on their host rocks, and our investigation on diamond forming processes and the characteristics of the diamondiferous mantle in these two locations, have the following implications for diamond and mantle petrology: 1)  The origin of “websteritic” diamonds. The integrated study of diamond inclusions and  diamondiferous xenoliths from Jericho (Section 3.5) clearly indicated that this suite is eclogitic. The compositions of garnets from websteritic xenoliths do not overlap with the compositions of garnets found included in diamonds (Fig. 4.11, 4.12, 4.14). High Mg contents found in garnet diamond inclusions (Table 4.3) and in garnets from eclogitic xenoliths (Appendix C, Table C1) are due to melt extraction and/or metasomatism at the time of diamond formation (Section 4.4; Smart et al., 2009). It is possible that diamonds containing high-Mg garnets found in other locations worldwide (Aulbach, 2002; Deines, 2002; Deines and Harris, 2004; Stachel and Harris,  136  2008) and classified as “websteritic” are indeed eclogitic and formed through similar processes as diamonds from Jericho. 2)  Interpretation of C and N isotopic data. The isotopic composition we documented for  the vast majority of diamonds from Jericho is unprecedented. All the hypotheses which have been made in the past to explain the origin of diamonds depleted in 13C, i.e. recycling of C-rich organic sediments in the mantle through subduction (e.g. Kirkley et al., 1991) and isotopic fractionation at mantle depth (e.g. Galimov, 1991) fail to explain values of δ13C as low as seen in Jericho diamonds (-35÷-41‰). The source of such isotopically light carbon is likely in a confined reservoir in the mantle, the origin of which may be correlated to the origin of the metasomatic agent responsible for diamond formation at Jericho. The combined study of C and N stable isotopes in Wawa diamonds also yielded peculiar results, with mantle-like (or slightly higher) δ13C values accompanied mostly by positive δ15N values, similar to the ones registered in marine organic sediments in subduction zones (Section 6.1.5). Our preferred explanation for such apparent discrepancy involves early recycling of crustal C and N through subduction and subsequent metasomatism caused by a C-rich mantle fluid or melt (Section 6.2.1 and 7.2). 3)  Implications of the occurrence of eclogitic diamonds on the northern edge of the Slave  Craton. An integrated study by Shirey et al. (2004) on the Kaapvaal craton based on diamond inclusions, mantle xenoliths, isotopic dating, and seismic profiles showed that the majority of the eclogitic diamond suites in that area occurred along the edge of the craton and, unlike harburgitic suites, were Proterozoic in age. The authors associated this occurrence with a “cratonic modification” phase, when an already formed, stabilized craton is affected by subduction processes occurring along its edges, causing the formation of eclogites, partial  137  melting, and metasomatism of the subcratonic mantle. By consequence, the mantle underneath the edge of the craton contains extensive eclogitic domains which appear to be more diamondiferous than the ones located underneath the central area of the craton. Based on the information we gathered on the mantle underneath the Northern Slave craton in this study, we can speculate that the model proposed by Shirey et al. (2004) is applicable to the Slave craton. The occurrence of diamond suites dominated by the peridotitic paragenesis in the central part of the Slave Craton (i.e. the Lac de Gras province) has been documented by several authors (Pokhilenko et al. 2004; Davies et al., 2004; Tappert et al, 2005), whereas no predominantly eclogitic suite has been reported from that same area, and that matches the situation of the Kaapvaal craton illustrated by Shirey et al. (2004). More studies on diamond inclusions and xenoliths from the northern part of the Slave craton, including isotopic dating, are needed to test this hypothesis. 4)  The origin of diamonds emplaced in orogenic settings. The models presented in  chapters 6and 7 represent a new insight on the origin and emplacement of diamonds brought to surface by non-kimberlitic magmas in orogenic settings. This study and the one carried out by Stachel et al (2006) showed that diamonds emplaced in an orogenic context can share several characteristics with diamonds found in intracratonic settings, including morphology, N contents and aggregation of N defects, and composition of mineral inclusions. While these pieces of evidence seem to exclude a subduction related origin for the studied diamond suite of Wawa, a deep mantle origin as suggested by Stachel et al. (2006) is hard to reconcile with the fact that these diamonds are found in calc-alkaline lamprophyres formed at depths shallower than the diamond stability field. The entrainment and exhumation process of Wawa diamonds has no  138  equivalent in diamond suites from other locations in similar tectonic contexts worldwide and certainly needs further studies to be elucidated.  7.4 Practical applications of this research One of the main discoveries made during this study is that the diamond paragenesis at Jericho is exclusively eclogitic. Our data is the first evidence that the model proposed by Shirey et al. (2004) for the eclogitic margins of the Kaapvaal is applicable to the Slave craton and, by consequence, to other cratons. This knowledge would have a major impact on the search and evaluation of diamond deposits in the area, as dispersion trains of indicator minerals with higher percentages of eclogitic garnets should be seen mainly on craton margins. Another aspect revealed by this study which is relevant to diamond exploration is the fact that diamondiferous eclogitic xenoliths from the Jericho kimberlite are enriched in Mg. The high-Mg character of the diamond paragenesis is also confirmed by the composition of garnets and clinopyroxenes found included in diamonds. Although this incidence is not entirely uncommon (e.g. Hills & Haggerty, 1989), the diamondiferous eclogites from Jericho are undoubtedly more magnesian than diamondiferous eclogites from most occurrences in Africa and Russia (Jacob, 2004). If the model shown in Fig. 7.1, which associates melt extraction, and consequent Mg-enrichment of eclogitic residues, with diamond formation turned out to be applicable to other locations across the northern Slave craton, then a completely new approach would have to be taken in tracing and identifying diamond resources in the area. For example, high-Mg eclogitic garnets and high-Mg omphacites would have to be considered the main markers of a potential diamond deposit, when analyzing indicator minerals found in glacial till from this area.  139  Finally, the discovery that orange and red cathodoluminescence in natural diamonds may be a sign of an uncommon origin in an orogenic setting is a valuable piece of information from a diamond exploration perspective as well, when the source of diamonds found in alluvial deposits is unknown. As we demonstrated in this study, diamonds formed in orogenic settings can have several characteristics in common with typical cratonic diamonds. However, while the vast majority of diamonds formed in the cratonic mantle have blue cathodoluminescence, diamonds from the Wawa area show predominantly orange-red cathodoluminescence and total absence of blue. Therefore, similar cathodoluminescence observed in alluvial diamonds may indicate that the source to be found is not a kimberlite, but some other volcanic rock emplaced in a nearby orogenic complex.  7.5 Limitations of methods, results, and implications The study of diamond in petrology has always presented a number of restrictions and limitations which are hard – and often impossible – to overcome. 1)  Availability of samples. The number of diamonds made available for science by mining  companies working in a certain area is normally very limited, and the access to the area for sampling (of diamonds, host kimberlites, and mantle xenoliths) precluded. Not knowing the precise areal distribution of the studied samples in the site and the characteristics of their host rocks is an obstacle to the interpretation of data obtained from diamonds. 2)  Inclusion studies: cracking diamonds vs. cutting and polishing diamond slabs. Both  techniques have been used to perform inclusions studies on diamonds from the two suites, and both presented pros and cons: cracking diamonds allows to extract most (if not all) inclusions above 20µ in size that are visible within the sample, but most of the information regarding the  140  spatial distribution of the inclusions within the diamond host is lost when using this technique; on the other hand, inclusions of all sizes can potentially be exposed on the surface of a cut and polished diamond slab, allowing perfect integration of inclusion data, growth studies with cathodoluminescence, and infrared spectrometry for N defects; however, it is impossible to expose all the inclusions within one diamond on a cut and polished slab surface, as they do not lie on the same plane, therefore a substantial amount of information on mineral inclusions is often lost, when using this technique; furthermore, cutting and polishing diamonds affected by secondary alteration and fracturing (as are both diamonds of Jericho and Wawa) is challenging and often not a viable option. When possible, the use of both techniques is recommendable. 3)  Combined study of C and N isotopes in diamond: elucidating but not always feasible.  As proven by our work on Wawa diamonds, the combined analyses of C and N isotopes, along with data on N content and aggregation state coming from FTIR, can be crucial in tracing the source for diamonds. However, when nitrogen contents are low (<100 ppm) and the size of diamonds (or diamond chips remaining after inclusions studies) small, the amount of nitrogen may be too small to perform accurate isotopic analyses using a combustion line like the one located at the IPGP (University of Paris VII) described in Cartigny et al., 1998.  7.6 Areas for future study The contribution provided by this study on the origin of eclogitic and “websteritic” diamonds is far from exhaustive and several questions remain open. Diamonds from Jericho are currently being studied by another research group (Smart et al., 2009b) according to which a model involving subduction, as opposed to a model based entirely on metasomatism, as proposed in this study, is a more viable option to explain the characteristics of these diamonds in terms of  141  mineral inclusions and C isotopes. More research needs to be done, both on Jericho and on other locations in the northern Slave craton where diamondiferous kimberlites have been discovered (e.g. Muskox, Hayman et al., 2009; Anuri, Masun et al., 2004). Firstly, a study on N stable isotopes in Jericho diamonds would be crucial to determine whether the source of N and C is crustal, as hypothesized by Smart et al. (2009b) or mantle-derived as we sustain in the present study. Secondly, an extensive study of mineral inclusions in diamonds from other kimberlites in the northern Slave would indicate whether or not the eclogitic mantle is indeed the only source for diamonds in this area. The integrated study of diamonds, diamond inclusions, and mantle xenoliths (both diamondiferous and barren) is what allowed us to understand that no actual websteritic diamond paragenesis exists in the Jericho suite and that the high Mg content in garnet diamond inclusions is due to metasomatism and/or melt extraction in the host rocks. The same approach should be taken, if possible, when studying diamonds from recently discovered kimberlites, as comparing the compositions of minerals in xenoliths and diamond inclusions provides a better understanding of the processes that took place in the cratonic mantle. As we pointed out in section 4.6.3, the isotopic signature of carbon found in diamonds from Jericho is unprecedented. With the data in our possession, a mantle derived source of isotopically “light” carbon (i.e. characterized by δ13C values considerably lower than the ones observed in organic carbon from marine sediments) seems to be the most sustainable hypothesis. If that hypothesis was to be proved right, this would open new scenarios in the study of carbon, especially concerning its role in the earth’s degassing history (Javoy et al., 1986; Cartigny et al., 1998). It is known that C defines a very large d13C range in meteorites (comparable to what is observed in eclogitic diamonds worldwide, ~-30 ÷ +2‰, Deines, 1980). Perhaps, more studies  142  on isotopes in diamonds from areas where significant “isotopic heterogeneities” have been found in the mantle, such as Botswana (Deines, 1993; 2002), could shed more light on this subject. The short supply of inclusion bearing diamonds from Wawa for this study was very limiting for the interpretation of inclusion parageneses, especially considering that a) distinct diamond populations have been identified at Wawa (Stachel, 2006; this study); b) unusual, mixed, unequilibrated inclusion parageneses have been found. New studies are being conducted on diamonds from the polymict volcaniclastic breccias of Wawa and more diamonds have been found in polymict conglomerates from the same area. The latter suite, due to the presence of kimberlite indicator minerals in the conglomerate’s matrix, may have been brought to the surface by kimberlites (Kopylova et al., 2010; Bruce et al., in press). A combined study of mineral inclusions and stable isotopes in diamonds from both breccias and conglomerates from Wawa would certainly represent an advance in the understanding of diamond genesis in this area. So far, the only certain occurrences of diamonds brought to surface by volcanic magmas in an orogenic context are at Wawa and Dachine, French Guyana (Capdevila et al., 1999; Cartigny et al., 2010), where diamonds are found in subduction related volcaniclastic komatiites. As is for Wawa diamonds, the origin of the Dachine diamonds and their entrainment by the subduction related magma that brought them to surface is still a matter of debate. The database on diamonds originated in these contexts needs to be extended, and more efforts need to be spent to locate the source rocks of alluvial diamonds found in orogenic contexts (e.g. diamonds from the New South Wales province in Australia, Davies et al., 2003). Cathodoluminescence (CL) imaging and spectrometry on Wawa diamonds from both breaccias and conglomerates has revealed the possibility of linking certain cathodoluminescence colours (orange, red) and certain CL spectral lines (575 nm; 637 nm) to metamorphism (Bruce at  143  al., in press). Unfortunately, CL is a scarcely used technique in diamond studies and most of the information on red cathodoluminescence and the spectral lines related to it comes from experimental studies on artificial diamonds (e.g. Zaitsev, 2000). A CL review on metamorphic diamonds, including those diamond suites which may have experienced metamorphism after the crystallization of diamond (as is likely the case for Wawa), would certainly fill that gap in the literature and possibly bring to surface correlations between CL and other diamond characteristics such as morphology and Nitrogen contents which are currently unknown due to the lack of data.  144  References Appleyard CM, Viljoen KS, and Dobbe R (2004) A study of eclogitic diamonds and their inclusions from the Finsch kimberlite pipe, South Africa. Lithos 77:317-332. Arias ZG, Helmstaedt H (1990) Structural evolution of the Michipicoten (Wawa) greenstone belt. Superior Province: evidence for an Archean fold and thrust belt. Geoscience Research Program, Summary of Research, 1989–1990. Ontario Geological Survey, Miscellaneous Paper 15, pp 107–114. Aulbach S, Stachel T, Viljoen KS, Brey GP, Harris JW (2002) Eclogitic and websteritic diamond source beneath the Limpopo Belt - Is slab-melting the link? Contrib Mineral Petrol 143:56-70. Aulbach S, Pearson NJ, O'Reilly SY, and Doyle, BJ (2007) Origins of xenolithic eclogites and pyroxenites from the Central Slave Craton, Canada: J. Petrol, 48:1843-1873.  Banas A, Stachel T, Muehlenbachs K, and McCandless T (2007) Diamonds from the Buffalo Head Hills, Alberta: formation in a non-conventional setting. Lithos 93:199-213. Barron LM, Barron BJ, Mernagh TP, and Birch WD (2008) Ultrahigh pressure macro diamonds from Copeton (New South Wales, Australia),based on Raman spectroscopy of inclusions. Ore Geology reviews 34: 76-86. Barth MG, Rudnick RL, Horn I, McDonough WF, Spicuzza MJ, Valley JW, and Haggerty SE (2002). Geochemistry of xenolithic eclogites from West Africa, part 2: Origins of the high MgO eclogites. Geochim Cosmochim Acta 66:4325-4345 Bebout GE, Fogel ML (1992) Nitrogen-isotope compositions of metasedimentary rock in the Catalina Schist, California: implications for metamorphic devolatilization history. Geochim. Cosmochim. Acta 56: 2839-2849 Bell DR, Gregoire M, Grove TL, Chatterjee N, Carlson RW, and Buseck PR (2005). Silica and volatileelement metasomatism of Archean mantle: a xenolith-scale example from the Kaapvaal Craton. Contrib Mineral Petrol 150(3): 251-267 Bostock MG (1997) Anisotropic upper-mantle stratigraphy and architecture of the Slave craton. Nature 390:392–395 Boyd SR, Mattly DP, Pillinger CT, Milledge HJ, Mendelssohn M, Seal, M (1987) Multiple growth events during diamond genesis: an integrated study of carbon and nitrogen isotopes and nitrogen aggregation state in coated stones. Earth and Planetary Science Letters 86: 341:353. Boyd SR (1989) Compositional distinction between oceanic and cratonic lithosphere. Earth Planet Sci Lett 96:15–26. Boyd SR, Hall A, and Pillinger CT (1993) The measurement of δ15N in crustal rocks by static vacuum spectrometry: application to the origin of the ammonium in the Cornubian batholiths, southwest England. Geochim. Cosmochim. Acta 57: 1339-1347. Boyd SR, Kiflawi I, Woods GS (1994) The relationship between infrared absorption and the A defect concentration in diamond. Philos Mag B69:1149–1153  145  Boyd SR, Kiflawi I, Woods GS (1995) Infrared absorption by the nitrogen aggregate in diamond. Philos Mag B72:351–361 Brey GP and Kohler T (1990) Geothermometry in four-phase lherzolites. II. New thermobarometers, and practical assessment of existing thermobarometers. J Petrol 31(6):1353-1378 Bruce LF, Kopylova MG, Longo M, Ryder J, Dobrzhinetskaya LF (in press) Luminescence of diamonds from metamorphic rocks. Accepted for publication by the American Mineralogist. Bulanova GP (1995) The formation of diamond. J Geochem Explor 53:1–23 Capdevila R, Arndt N, Letendre J, and Sauvage J-F (1999) Diamond in volcaniclastic komatiites from French Guiana. Nature 399: 456-458.  Caporuscio FA and Smyth JR (1990) Trace element crystal chemistry of mantle eclogites. Contrib Mineral Petrol, 105: 550-561. Cartigny P, Stachel T, Harris J, and Javoy, M (2004) Constraining diamond metasomatic growth using Cand N-stable isotopes; examples from Namibia. Lithos 77(1-4):359-373 Cartigny P (2005) Stable isotopes and the origin of diamond. Elements 1:79-84 Cartigny P, Harris JW, Phillips D, Boyd SR, Javoy M (1998) Subduction-related diamonds? The evidence for a mantle-derived origin based on δ13C-δ15N measurements. Chem Geol 147:147-159 Chen Z (1999) Inter-element fractionation and correction in laser ablation ICPMS. J of Analytical Atomic Spectrometry 14: 1823-1828 Chopin C (2003) Ultrahigh-pressure metamorphism: Tracing continental crust into the mantle. Earth and Planetary Science Letters 212:1-14. Clark CD, Collins AT, Woods GS (1992) Optical spectroscopy of diamond. In: Field JE (ed) The properties of natural and synthetic diamond, Academic Press, New York, pp 35-69 Coleman RG, Lee DE, Beatty LB and Brannock WW (1965) Eclogites and eclogites; their differences and similarities. GSA Bulletin 76(5):483-508 Cook FA, van der Velden AJ, Hall KW, and Roberts BJ (1999) Frozen subduction in Canada's Northwest Territories; Lithoprobe deep lithospheric reflection profiling of the western Canadian Shield. Tectonics 18:1-24 Cookenboo HO, Kopylova MG, and Daoud DK (1998a) A chemically and texturally distinct layer of diamondiferous eclogite beneath the central Slave craton, Northern Canada. In: Extended Abstracts, 7th International Kimberlite Conference, Cape Town, pp. 164–166 Davies G (1976) The nitrogen aggregate in diamond - its symmetry and possible structure. Journal of Physics C: Solid State Physics, 17: L399-L403.  146  Davies G (1999) Current problems in diamond: towards a quantitative understanding. Physica B:Condensed matter, Vol 273-274: 15-23. Davies RM, Griffin WL, O’ Reilly SY, Doyle BJ (2004) Mineral Inclusions and geochemical characteristics of microdiamonds from the DO27, A154, A418, DO18, DD17 and Ranch Lake kimberlites at Lac de Gras, Slave Craton, Canada. Lithos 77:39-55 Deer, WA (1997). Rock-Forming Minerals. Geological Society of London. 668 p. De Corte K, Cartigny P, Schatsky VS, De Paepe P, Sobolev NV, Javoy M (1999) Characteristics of microdiamonds from UHPM rocks of the Kotchetav Massif (Kazakhstan). In: Dawson JB and Nixon PH (eds) Proceedings of the 7th International Kimberlite Conference, Cape Town, Vol. 1, pp 174-182 Deines P, Harris JW, Gurney JJ (1993) Depth-related carbon isotope and nitrogen concentration variability in the mantle below the Orapa kimberlite, Botswana, Africa. Geochimica et Cosmochimica Acta 57: 2781-2796. Deines P (2002) The carbon isotope geochemistry of mantle xenoliths. Earth Sciences Reviews 58, 247278 Deines P and Harris JW (2004) New insights into the occurrence of 13C-depleted carbon in the mantle from two closely associated kimberlites: Letlhakane and Orapa, Botswana. Lithos 77:125-142 Deljanin B, and Simic D (2007) Laboratory-grown Diamonds, Information Guide to HPHT-grown and CVD-grown. Diamonds Book, 2nd edition. Dobrzhinetskaya, LF, Eide E, Korneliussen A, Larsen R, Millege J, Posukhova T, Smith DS, Sturt BA, Taylor WR and Tronnes R (1995). Diamond in metamorphic rocks of the Western Gneiss Region in Norway. Geology 23: 597– 600. Dobrzhinetskaya L F and Green HW (2001). Inclusions in microdiamonds from UHP-metamorphic rocks: evidence of the crust–mantle interactions. Ultra-High-Pressure-Metamorphism Workshop. Waseda University, Tokyo, Japan. Session 1, A04, 8–9. Dobrzhinetskaya LF, Green HW, Bozhilov KN, Mitchell TE, and Dickerson RM (2003) Crystallization environment of Kazakhstan microdiamond: evidence from nanometric and mineral associations. J Metamorphic Geol 21:425-437. Ellis DJ and Green DH (1979) An experimental study of the effect of Ca upon garnet-clinopyroxene Fe – Mg exchange equilibria. Contrib Mineral Petrol 71:13-22 England P, Wilkins C (2004) A simple analytical approximation to the temperature structure in subduction zones. Geophys J Int 159:1138–1154 Evans T, and Qi Z (1982) The kinetics of aggregation of nitrogen atoms in diamond. Proceedings of the Royal Society of London A381, 159-178. Evans T and Harris JW (1989) Nitrogen aggregation, inclusion equilibration temperatures and the age of diamonds. In: Ross J et al. (eds.) Kimberlites and Related Rocks v.2. Their Mantle/Crust Setting. Spec. Publ. Geol. Soc. Aust. Vol. 14, pp. 1002–1006  147  Evans T (1992) Aggregation of nitrogen in diamonds. In: Field JE (Ed) The properties of natural and synthetic diamond. Academic, New York, pp 259–290. Field SW, and Haggerty SE (1994) Symplectites in upper mantle peridotites: development and implications for the growth of subsolidus garnet, pyroxene and spinel. Contrib Mineral Petrol 118:138– 156.  Finnie KS, Fisher D, Griffin WL, Harris JW, and Sobolev NV (1994) Nitrogen aggregation in metamorphic diamonds from Kazakhstan. Geoch et Cosmo Acta 58(23): 5173-5177. Fritsch E (1998) The nature of color in diamonds. In: Harlow GE (Ed) The Nature of Diamonds, Cambridge University Press, Cambridge, UK, pp. 23–47 Galimov, EM, Solov’yeva, LV, and Belomestnykh, AV (1989) Carbon isotope composition of metasomatised mantle rocks. Geochem. Int. 26 (11), 38 – 43. Galimov EM (1991) Isotope fractionation related to kimberlite magmatism and diamond formation. Geochim Cosmochim Acta 55:1697-1708 Gerya TV, Yuen DA (2003) Rayleigh–Taylor instabilities from hydration and melting propel “cold plumes” at subduction zones. Earth Planet Sci Lett 212:47–62 Graham RJ, Ravi KV (1992) Cathodoluminescence investigation of impurities and defects in single crystal diamond grown by the combustion-flame method. Appl Phys Lett 60:1310–1312 Gurney JJ (1984) A correlation between garnets and diamonds in kimberlites. In: Glover JE, Harris PG (eds) Kimberlite occurrence and origin: a basis for conceptual models in exploration, vol 8. Publishers of the Geology Department and University Extension, University of Western Australia, pp 143–166. Gurney JJ, 1989. Diamonds. In: Ross, J. (Ed.), Kimberlites and Related Rocks Geol. Soc. Spec. Publ. vol. 14. Blackwell, Carlton, pp. 966–989 Gurney JJ, Hildebrand PR, Carlson JA, Fedortchouk Y, Dyck DR (2004) The morphological characteristics of diamonds from the Ekati property, Northwest Territories, Canada. Lithos 77: 21-38. Haendel D, Mühle K, Nitzsche H, Stiehl G, Wand U (1986) Isotopic variations of the fixed nitrogen in metamorphic rocks. Geochim Cosmochim Acta 50: 749-758. Haggerty SE (1986) Diamond genesis in a multiply-constrained model. Nature 320: 34-38. Hanley PL, Kiflawi I, Lang AR (1977) On topographically identifiable sources of cathodoluminescence in natural diamonds. Philos Trans R Soc Lond A284:329–368 Harris JW (1987). Recent physical, chemical, and isotopic research of diamond. In: Nixon, PH (Ed), Mantle Xenoliths. Miley, Chichester, pp. 477-500. Harris JW (1992) Diamond Geology. In: Field JE (Ed.) The Properties of Natural and Synthetic Diamond, Academic Press, San Diego, 345-388  148  Harris JW, and Gurney JJ (1979). Inclusions in diamond. In: Field JE (Ed.) The Properties of Natural and Synthetic Diamond, Academic Press, London, 555-591. Harris, JW, Hawthorne, JB, Oosterveld, MM, and Wehmeyer, E (1975). A classification scheme for diamond and a comparative study of South African diamond characteristics. Physics and Chemistry of the Earth 9:765-783. Hayman PC, Kopylova MG, Kaminsky FV (2005) Lower mantle diamonds from Rio Soriso (Juina, Brazil). Contrib Mineral Petrol 149 (4): 430-445. Hayman PC, Cas RAF, Johnson M, Foley SF (2009) Characteristics and alteration origins of matrix minerals in volcaniclastic kimberlite of the Muskox Pipe (Nunavut, Canada). Lithos 112: 473-487 Heaman LM, Creaser RA, and Cookenboo HO (2002) Extreme enrichment of high field strength elements in Jericho eclogite xenoliths: A cryptic record of Paleoproterozoic subduction, partial melting, and metasomatism beneath the Slave craton, Canada. Geology 30(6):507-510 Heaman LM, Creaser RA, Cookenboo HO, and Chacko T (2006) Multi-Stage Modification of the Northern Slave Mantle Lithosphere: Evidence from Zircon- and Diamond-Bearing Eclogite Xenoliths Entrained in Jericho Kimberlite, Canada. J Petrol 47(4):821-858 Helmstaedt HH and Schulze DJ (1989). Southern African kimberlites and their mantle sample: implications for Archean tectonics and lithosphere evolution. In: Ross J, Jaques AL, Ferguson J, Green DH, O'Reilly SY, Danchin RV, Janse AJA (Eds.), Kimberlites and related rocks. Geological Society of Australia Special Publication, vol. 14. Blackwell, Carlton, pp. 358–368. Hills DV and Haggerty SE (1989) Petrochemistry of eclogites from the Koidu kimberlite complex, Sierra Leone. Contrib Mineral Petrol 103:397-422 Iancu OG, Cossio R, Korsakov AV, Compagnoni R, and Popa C (2008) Cathodoluminescence spectra of diamonds in UHP rocks from the Kotchetav Massif, Kazakhstan, Journal of Luminescence 128: 16841688. Iakoubovskii K, Adriaenssens GJ (1999) Photoluminescence in CVD diamond films. Phys Status Solidi—Appl Res 172:123–129 Ireland TA, Rudnick RL, and Spetsius Z (1994) Trace elements in diamond inclusions from eclogites reveal link to Archean granites. Earth Planet Sci Lett 128, pp. 199 -213 Jacob DE (2004) Nature and origin of eclogite xenoliths from kimberlites. Lithos 77:295-313 Jaques AL, Hall AE, Sheraton JW, Smith CB, Sun SS, Drew RM, Foudoulis C, And Ellingsen K, (1989). Composition of crystalline inclusions and C-isotopic composition of Argyle and Ellendale diamonds. In: Ross J, Jaques AL, Ferguson J, Green DH, O'Reilly SY, Danchin RV, Janse AJA (Eds.), Kimberlites and related rocks. Geological Society of Australia Special Publication, vol. 14. Blackwell, Carlton, pp. 966–989. Javoy M, Pinaeu F, and Dernaiffe (1984) Nitrogen and carbon isotopic composition in the diamonds of Mbuji Mayi (Zaire). Earth and Plantetary Science Letters 68, 399-412. Javoy M, Pinaeu F, Delorme H (1986) Carbon and nitrogen isotopes in the mantle. Chem Geol 57:41–62  149  Jerde EA, Taylor LA, Crozaz G, Sobolev NV, and Sobolev VN (1993) Diamondiferous eclogites from Yakutia, Siberia: evidence for a diversity of protoliths. Contrib Mineral Petrol 114:189-202 Kaminsky FV, Zakharchenko OD, Griffin WL, Channer DMD, Khachatryan-Blinova GK (2000) Diamond from the Guaniamo area, Venezuela. Can Mineral 38:1347-1370 Kennedy CS and Kennedy GC (1976) The equilibrium boundary between graphite and diamond. J Geoph Res 81(B14):2467-2470 Kerr AC (2003) Oceanic Plateaus. In: Holland HD and Turekian KK (eds) Treatise on Geochemistry v.3 The Crust: 537-565. Ketchum JWF, Ayer JA, Van Breemen O, Perason NJ, and Becker JK (2008). Pericontinental Crustal Growth of the Southwestern Abitibi Subprovince, Canada—U-Pb, Hf, and Nd Isotope Evidence. Economic Geology 103: 1151-1184. Klein C, Hurlburt CS, Jr (1985). Manual of Mineralogy. John Wiley and Sons Inc., New York. Klein (2003) Geochemistry of the igneous oceanic crust. In: Holland HD and Turekian KK (eds) Treatise on Geochemistry v.3 The Crust: 433-463. Kopylova MG, Russell JK, and Cookenboo HO (1998b) Upper-mantle stratigraphy of the Slave craton, Canada: Insights into a new kimberlite province. Geology, v 26, n. 4: 315-318. Kopylova MG, Russell JK, and Cookenboo HO (1999a) Mapping the lithosphere beneath the North CentralSlave Craton. In: Dawson JB and Nixon PH (eds) Proceedings of the 7th International Kimberlite Conference, Cape Town, Vol. 1, pp. 468-479 Kopylova MG, Russell JK and Cookenboo HO (1999b) Petrology of peridotite and pyroxenite xenoliths from the Jericho kimberlite: implications for the thermal state of the mantle beneath the Slave craton, northern Canada. J Petrol 40:79-104 Kopylova MG, Lo J and Christensen NI (2004) Petrological constraints on seismic properties of the Slave upper mantle (Northern Canada). Lithos 77:493-510 Kopylova MG (2003) Two distinct origins of the northern Slave eclogites. Extended Abstract, 8th Intern. Kimb. Conference, Victoria, Canada, May 2003. Kopylova MG and Hayman P (2008) Petrology and textural classification of the Jericho kimberlite, Northern Slave Province, Nunavut, Canada. Can J Earth Sci 45(6):701-723 Le Bas MJ (2000) IUGS Reclassification of the high-Mg and picritic volcanic rocks. J. Petrol 41(10):14671470 Lefebvre NS (2004) Petrology, volcanology, and diamonds of Archean calc-alkaline lamprophyres, Wawa, Ontario, Canada. Unpublished Master Thesis, University of British Columbia. Lefebvre N, Kopylova M, Kivi K (2005) Archean calc-alkaline lamprophyres of Wawa, Ontario, Canada: unconventional diamondiferous volcaniclastic rocks. Precambrian Res 138:57–87  150  Lehmann B, Burgess R, Frei D, Belyatsky B, Mainkur D, Chalapathi Rao NV, and Heaman LM (2010) Diamondiferous kimberlites in central India synchronous with Deccan flood basalts. Earth Planet. Sci Lett 290: 142–149. Lindblom J, Holsa J, Papunen H, Hakkanen H, Mutanen J (2003) Differentiation of natural and synthetic gem-quality diamond by luminescence properties. Opt Mater 24:243–251 Liu G, Wang XB, Wen QB (1998) Carbon isotopic composition of mantle xenoliths in alkali basalt from Damaping, Hebei. Chin. Sci. Bull. 43(24):2095-2098 Luth RW (2003) Mantle volatiles - distribution and consequences. In: Holland HD and Turekian KK (eds) Treatise on Geochemistry v.2 The mantle and core: 319-361. Magee CW, Taylor WR (1999) Constraints from luminescence on the history and origin of carbonado. In: Gurney JJ, Gurney JL, Pascoe MD, Richardson SH (Eds) Proceedings of the 7th international kimberlite conference, Red Roof Design, Cape Town, pp 529–532 Marinelli M, Hatta A, Ito T, Hiraki A, Nishino T (1996) Band-A emission in synthetic diamond films: a systematic investigation. Appl Phys Lett 68:1631–1633 Martineau PM, Lawson SC, Taylor AJ, Quinn SJ, Evans DJF, Crowder MJ (2004) Identification of synthetic diamond grown using chemical vapor deposition (CVD). Gems Gemol 40:2–25 Masaytis VL, Gnevushev MA and Shafranovsky, GI (1979) Mineral assemblages and mineralogical criteria of genesis of astroblemes. Zap. Vses. Mineral. Ova. 108(3): 257-273 (in Russian). Massonne H-J (1999). A new occurrence of microdiamonds in quartzofeldspathic rocks of the Saxonian Erzgebirge, Germany, and their metamorphic evolution. In: Gurney JJ, Gurney JL, Pascoe MD and Richardson SH (Eds) Proceedings of the 7th International Kimberlite Conference pp. 533– 539. Red Roof Design cc, Cape Town. Masun KM, Doyle BJ, Ball S, Walker S (2004) The geology and mineralogy of the Anuri kimberlite, Nunavut, Canada. Lithos 76: 75-97. McCandless TE, Weldman MA, Gurney JJ (1994). Macrodiamonds and microdiamonds from Murfreesboro Lamproites, Arkansas: Morphology, mineral inclusions, and carbon isotope geochemistry. The 5th International Kimberlite Conference, Brasilia, Brazil, Companhia de Pesquisa de Recursos Minerals, pp. 78-97. McCallum ME, Huntley PM, Falk RW, Otter ML (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, Brazil, Companhia de Pesquisa de Recursos Minerals, pp 78–97 McDonough WF and Sun SS (1995) The composition of the Earth. Chem Geol 120:223-253 McKenna N, Gurney JJ, Klump J, and Davidson JM (2004) Aspects of diamond mineralization and distribution at the Helam mine, South Africa. Lithos 77:193-208  151  McNamara KM, Rutledge K, and Gleason KK (1997). Characterization methods. In: Prelas MA, Popovici G and Bigelow LK (Eds.) Handbook of Industrial Diamonds and Diamond Films, Mercel Dekker Inc., New York, 413-480. Mendelssohn MJ and Milledge HJ (1995) Geologically significant information from routine analysis of the mid-infrared spectra of diamonds Meyer HOA (1987) Inclusions in diamond. In Nixon PH (ed) Mantle Xenoliths, John Wiley and Sons, Toronto, pp 501-522 Mibe K, Fujii T, Yasuda A (2002) Composition of aqueous fluid coexisting with mantle minerals at high pressure and its bearing on the differentiation of the Earth's mantle Geochim Cosmochim Acta 66(12):2273-2285 Milledge HJ, Woods PA, Beard AD, Shelkov D, Willis B (1999) Cathodoluminescence of polished carbonado. In: Gurney JJ, Gurney JL, Pascoe MD, Richardson SH (Eds) Proceedings of the 7th international kimberlite conference, Red Roof Design, Cape Town, pp 589–590 Misra, K. C., M. Anand, Taylor LA, and Sobolev NV (2004) Multi-stage metasomatism of diamondiferous eclogite xenoliths from the Udachnaya kimberlite pipe, Yakutia, Siberia. Contrib Mineral Petrol 146(6):696-714. Mitchell RH (1995) Kimberlites, orangeites, and related rocks. Plenum Press, New York, 410 pp. Moser DE, Heaman LH, Krogh TE, and Hanes JA (1996). Intracrustal extension of an Archean orogen revealed using single-grain U-Pb zircon geochronology: Tectonics 15: 1093–1109. Mposkos ED, and Kostopoulos DK (2001). Diamond, former coesite and supersilicic garnet in metasedimentary rocks from the Greek Phodope: a new ultrahigh-pressure metamorphic province established. Earth and Planetary Science Letters 192:497–506. Orlov YL (1977). Mineralogy of the Diamond. New York, Izdatel’stvo Nauka SSSR. Translated in 1977 from the Russian language. Wiley and Sons, New York. Otter ML, McCallum ME, and Gurney JJ (1994) A physical characterization of the Sloan (Colorado) diamonds using a comprehensive diamond description scheme. In Proceedings of the 5th International Kimberlite Conference (Eds Meyer HOA, and Leonardos OH), Vol. 2, pp. 15-31. Companhia de Pesquisa de Recursos Minerais (CPRM), Brasilia, Brazil. Paczner G, Gaft M, Marfunin A (2000) Systems of interacting luminescence centers in natural diamonds: laser-induced time-resolved cathodoluminescence spectroscopy. In: Pagel M, Barbin V, Blanc P, Ohenstetter D (Eds) Cathodoluminescence in geosciences. Springer, Berlin Heidelberg New York 514 pp Pal’yanov YN and Sokol AG (2009) The effect of composition of mantle fluids/melts on diamond  formation processes. Lithos 112 (Proceedings of the 9th International Kimberlite Conference): 690-700.  152  Pal’yanov YN, Schatsky VS, Sobolev NV, and Sokol AG (2007) The role of mantle ultrapotassic fluids in diamond formation. Proceedings of the National Academy of Sciences of the United States of America 104(22):9122-9127. Passchier CW, and Trouw RAJ (1996) Microtectonics. Springer-Verlag, Berlin, 289 pp. Pearson DG, Shirey SB, Bulanova GP, Carlson RW, Milledge HJ (1999). Re–Os isotope measurements of single sulfide inclusions in a Siberian diamond and its nitrogen aggregation systematics. Geoch et Cosmo Acta 63: 703–711. Pearson DG, Canil D, Shirey SB (2002) Mantle samples included in volcanic rocks: xenoliths and diamonds. In: Carlson RW (ed) Treatise on geochemistry, vol 2. Elsevier, Amsterdam, pp 171–275 Percival JA, and West GF (1994) The Kapuskasing uplift: A geological and geophysical synthesis: Can J Earth Sc 31:1256–1286. Percival JA, Green AG, Milkereit B, Cook FA, Geis W, and West GF (1989) Seismic reflection profiles across deep continental crust exposed in the Kapuskasing uplift structure. Nature 342: 416–420. Peters KE, Sweeney RE, and Kaplan IR (1978) Correlation of carbon and nitrogen stable isotope ratios in sedimentary organic matter. Limnol. Oceanogr. 23, 598-604. Phillips D, Harris JW, and Viljoen KS (2004) Mineral chemistry and termobarometry of inclusions from De Beers Pool diamonds, Kimberley, South Africa. Lithos 77:155-179 Pokhilenko NP, Sobolev NV, Reutsky VN, Hall AE, and Taylor LA (2004) Crystalline inclusions and C isotope ratios in diamonds from the Snap Lake/King Lake kimberlite dyke system: evidence of ultradeep and enriched lithospheric mantle. Lithos 77:57-67. Pollack HN, Chapman DS (1977) On the regional variation of heat flow, geotherms, and lithospheric thickness. Tectonophysics 38:279–296. Pollack HN, Hurter SJ, Johnston JR (1993) Heat flow from the Earth’s interior: analysis of the global data set. Rev Geophys 31(3):267–280. Polat A (2009) The geochemistry of Neoarchean (ca. 2700 Ma) tholeiitic basalts, transitional to alkaline basalts, and gabbros, Wawa subprovince, Canada: Implications for petrogenetic and geodynamic processes. Richardson SH, Gurney JJ, Erlank AJ, Harris JW (1984) Origin of diamonds in old enriched mantle. Nature 310: 198-202. Robertson R, Fox JJ, and Marti AE (1934) Two types of diamond. Phylosophical Transactions. Royal Society of London A323, 463. Robinson DN (1979). The characteristics of natural diamond and their interpretation. Unpublished PhD. Thesis, University of Cape Town. Robinson DN, Scott JA, Van Niekerk A, and Anderson VG (1989) The sequence of events reflected in diamonds of some southern African kimberlites. In: Ross J (Ed), Kimberlites and Related Rocks Volume  153  2: Their Mantle/Crust Setting, Diamonds, and Diamond Exploration. Victoria, Australia, Blackwell Scientific. Geological Society of Australia Publication 14: 990-1000. Rock NMS (1991) Lamprophyres. Blackie, Glasgow, 286 pp Rubatto D, and Hermann J (2001) Exumation as fast as subduction? Geology 29: 3-6. Russell JK, Dipple GM, and Kopylova MG (2001) Heat production and heat flow in the mantle lithosphere, Slave craton, Canada. Phys Earth Planet Int 123(1):27-44 Rybachikov I (1982) Compositions of aqueous fluids in equilibrium with pyroxenes and olivines at mantle pressures and temperatures. Contrib Mineral Petrol 79:80-84. Ryder J, Verley CG, Miller A, Martel B, and Khoun R (2008). The diamondiferous conglomerates of the Leadbetter Project. 9th International Kimberlite Conference Extended Abstract 9IKC-A-00110. Schertl HP, Okay AI (1994) A coesite inclusion in dolomite in Dabie-Shan, China—petrological and theological significance. Eur J Mineral 6:995–1000 Sage RP (1994) Geology of the Michipicoten Greenstone Belt. Ontario Geological Survey, Sudbury, Open file report 5888, 592 pp Sage RP, Lightfoot PC, Doherty W (1996a) Bimodal cyclical Archean basalts and ryolites form 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 Res 76:119–153 Sage RP, Morris TF, Crabtree D, Murray CA, Bennett G, Hailstone M, Nicholson T, Pianosi S, Josey S (1996b) Ultramafic dike with mantle xenoliths; implications to diamond exploration in Wawa. In: Proceedings and abstracts—Institute on Lake Superior Geology meeting, vol 42, Part 1, 52 pp Schidlowski M (2001) Carbon isotopes as biogeochemical recorders of life over 3.8 Ga of Earth history: evolution of a concept. Precambrian Research 106:117-134 Schmidberger SS, Simonetti A, Heaman LM, Creaser RA, and Whiteford S (2007) Lu-Hf, in-situ Sr and Pb isotope and trace element systematics for mantle eclogites from the Diavik diamond mine: Evidence for Paleoproterozoic subduction beneath the Slave craton, Canada. Earth Planet Sc Lett 254(1-2):55-68 Schulze DJ, Harte B, Valley JW, DeR. Channer DM (2004) Evidence of subduction and crust-mantle mixing from a single diamond. Lithos 77: 349-358. Schulze DJ, Canil D, Channer DM DeR, and Kaminsky FV (2006). Layered mantle structure beneath the western Guyana Shield, Venezuela: Evidence from diamonds and xenocrysts in Guaniamo kimberlites. Geoch et Cosmo Acta 70:192-205. Smart K, Heaman LM, Chacko T, and Simonetti A (2007) Mineral Chemistry and Clinopyroxene Sr-Pb compositions of mantle eclogite xenoliths from the Jericho Kimberlite, Nunavut. Abstracts GAC-MAC Conference, Yellowknife, Vol. 32, p 76  154  Smart K, Heaman LM, Chacko T, Simonetti A, Kopylova MG, Mah D, ans Daniels D (2009) The origin of high-MgO diamond eclogites from the Jericho Kimberlite, Canada. Earth and Planetary Science Letters 284: 527-537. Smith D and Boyd FR (1992) Compositional zonation in garnets in peridotite xenoliths. Contrib. Miner. Petrol. 112 (1) 134-147  Sobolev NV and Shatsky VS (1990). Diamond inclusions in garnets from metamorphic rocks: a new environment for diamond formation. Nature 343: 742–745 Sobolev NV, Yefimova ES and Koptil VI (1999) Mineral inclusions in diamonds in the Northeast of the Yakutian diamondiferous province. In: Dawson JB and Nixon PH (eds) Proceedings of the 7th International Kimberlite Conference, Cape Town, Vol. 2, pp 816-823 Sobolev VN, Taylor LA, Snyder GA, Sobolev NV, Pokhilenko NP, Kharkiv AD, Mitchell RH (1997) In: Sobolev RH (Ed) Proceedings of the 6th International Kimberlite Conference, Volume 1, 218-228. Sokol AG, Y. N. Pal'yanov YN, Pal’yanova GA, Khokhryanov AF, Borzdov YM (2001) Diamond and graphite crystallization from C-O-H fluids under high pressure and high temperature conditions. Diamond and Related Materials 10(12):2131-2136 Sokol, AG and Pal'yanov YN (2008) Diamond formation in the system MgO-SiO2-H2O-C at 7.5 GPa and 1,600 degrees C. Contrib Mineral Petrol 155(1):33-43 Spetsius, ZV (1999) Two generations of diamonds in eclogite xenoliths from Yakutia. In: Dawson JB and Nixon PH (eds) Proceedings of the 7th International Kimberlite Conference, Cape Town, Vol. 2, pp.823828 Stachel T and Harris JW (1997) Syngenetic inclusions in diamond from the Birim field (Ghana) - a deep peridotitic profile with a history of depletion and re-enrichment. Contrib Mineral Petrol 127:336-352 Stachel T, Harris JW, Aulbach S, Deines P (2002) Kankan diamonds (Guinea) III; δ13C and nitrogen characteristics of deep diamonds. Contrib Mineral Petrol 142:465-475 Stachel T, Aulbach S, Brey GP, Harris JW, Leost, I, Tappert, R, Viljoen, KS (2004) The trace element composition of silicate inclusions in diamonds; a review. Lithos 77(1-4):1-19 Stachel T, Banas A, Muehlenbachs K, Kurszlaukis S, Walker EC (2006) Archean diamonds from Wawa (Canada): samples from deep cratonic roots predating cratonization of the Superior Province. Contrib Mineral Petrol 151: 737–750. Stachel T and Harris JW (2008) The origin of cratonic diamonds - constraints from mineral inclusions. Ore Geol Rev 34(1-2):2-32. Staudigel H, and King SD (1992) Ultrafast subduction - the key to slab recycling efficiency and mantle differentiation, Earth Planet. Sci. Lett. 109: 517-530. Stern RA, Hanson GN (1992) Marathon dykes: Rb–Sr and K–Ar geochronology of ultrabasic lamprophyres from the vicinity of McKillar Harbour, northwestern Ontario, Canada. Can J Earth Sci 20:193–227  155  Stern RJ (2002) Subduction zones. Rev Geophys 40(4):3–38 Stockhert B, Duyster J, Trepmann C, Masonne HJ (2001) Microdiamond daughter crystals precipitated from supercritical COH + silicate fluids included in garnet, Erzgebirge, Germany. Geology 29:391–394 Sunagawa I (1984). Morphology of natural and synthetic diamonds. IN: Sunagawa I. (Ed), Material Science of the Earth’s Interior. Terra Scientific Publishing Company and D. Reidal Publishing Company, Tokyo, Japan, pp 61-103. Szabo’ C and Bodnar RJ (1995) Chemistry and origin of mantle sulfides in spinel peridotite xenoliths from alkaline basaltic lavas, Nograd-Gomor volcanic field, northern Hungary and southern Slovakia. Geochim Cosmochim Acta 59(19):3917-3927 Takeuchi D, Watanabe K, Yamanaka S, Okushi H (2001) Origin of band-A emission in diamond thin films. Phys Rev B 63:245328-1–245328-7 Tappert R, Stachel T, Harris JW, Shimizu N and Brey GP (2005) Mineral inclusions in diamonds from thePanda kimberlite, Slave Province, Canada. Eur J Mineral 17(3):423-440 Taylor LA and Neal CR (1989) Eclogites with oceanic crustal and mantle signatures from the Bellsbank kimberlite, South Africa, Part I: Mineralogy, petrography, and whole rock chemistry. J of Geology 97:551-567. Taylor LA, Snyder GA, Crozaz G, Sobolev VN, Yefimova ES, and Sobolev NV (1996a). Eclogitic inclusions in diamonds: evidence of complex mantle processes over time. Earth and Planetary Science Letters 142: 535–551. Taylor LA; Milledge HJ, Bulanova GP, Snyder GA, and Keller, RA (1998) Metasomatic eclogitic diamond growth; evidence from multiple diamond inclusions. Inter Geol Rev 40(8):663-676 Taylor LA, Snyder GA, Keller R, Remley DA, Anand M, Wiesli, R, Valley, J, Sobolev NV (2003) Petrogenesis of group A eclogites and websterites; evidence from the Obnazhennaya Kimberlite, Yakutia. Contrib Mineral Petrol 145(4):424-443 Taylor WR, Jacques AL, and Ridd M (1990) Nitrogen-defect aggregation characteristics of some Australian diamonds: time-temperature constraints on the source region of pipe and alluvial diamonds. Am Mineral 75:1290-1310 Thomassot E, Cartigny P, Harris JW and Viljoen KS (2007) Methane-related diamond crystallization in the Earth's mantle: Stable isotope evidences from a single diamond-bearing xenolith: Earth Planet Sci Lett 257:362-371. Thurston PC (2002) Autochthonous development of Superior Province greenstone belts? Precambrian Res 115:11–36 Ulmer P (2001) Partial melting in the mantle wedge—the role of H2O in the genesis of mantle-derived “arc-related” magma. Phys Earth Planet Interiors 127:215–232 Van Breemen O, King JE and Davis WJ (1989) U-Pb zircon and monazite ages from plutonic rocks in the Contwoyto –Nose Lakes map area, central Slave, District of Mackenzie. In: Radiogenic ages and isotope  156  studies, Report 3, Geological Survey of Canada, paper 89-2, pp 29-38 Verley CG (2009) Updated NI 43-101 Technical Report on the Leadbetter Diamond Project. Dianor Resources, Inc., Val D’Or, Canada. Viljoen KS, Phillips D, Harris JW, and Robinson DH (1999) Mineral inclusions in diamonds from the Venetia kimberlites, Northern Province, South Africa. In: Dawson JB and Nixon PH (eds) Proceedings of the 7th International Kimberlite Conference, Cape Town, Vol. 2, pp.888-895. Walter MJ (1999). Melting residues of fertile peridotite and the origin of cratonic lithosphere. In: Fei, Y., Bertka, C.M., Mysen, B.O. (Eds.), Mantle petrology: field observations and high pressure experimentation: A tribute to Francis R. (Joe) Boyd. Special Publication, The Geochemical Society, Houston, pp. 225–239. Wendland C (2010). Diamondiferous mass-flow and traction current deposits in a Neoarchean Fan Delta, Wawa Area, Superior Province. Unpublished MSc. Thesis, Lakehead University, 2010 Williams F (2002) Diamonds in late Archean calc-alkaline lamprophyres, Ontario, Canada: origins and implications. BSc (Honours) Thesis, University of Sydney, Sydney, Australia, 85 pp Woods GS (1986). Platelets and the infrared absorption of Type Ia diamonds. Proceedings of the Royal Society of London, A407, 219-238. Wyman D, Kerrich R (1993) Archean shoshonitic lamprophyres of the Abitibi Subprovince, Canada: petrogenesis, age, and tectonic setting. J Petrol 34:1067–1109 Xu S, Okay AL, Sengor A, Su W, Liu Y and Jiang L (1992). Diamond from the Dabie Shan metamorphic rocks and its implication for tectonic setting. Science 256: 80–82. Yang X, Barnes AV, Albert MM, Albridge JT, McKinley JT, Tolk NH, Davidson JL (1995) Cathodoluminescence and photoluminescence of chemical-vapor-deposited diamond. J Appl Phys 77:1758–1761 Yokochi R, Marty B, Chazot G, and Burnard P (2009) Nitrogen in peridotite xenoliths: lithophile behavior and magmatic isotope fractionation. Geochimica et Cosmochimica Acta 73(16): 4843-4861 Zaitsev A (2001) Optical properties of diamond; a data handbook. Springer, Berlin Heidelberg New York, 502 pp. Zito G, Mongelli F, De Lorenzo S, Doglioni C (2003) Heat flow and geodynamics in the Tyrrhenian Sea. Terra Nova 15:425–432  157  Appendix A. Characteristics of diamonds from Jericho and Wawa  158  Table A1. Characteristics of diamonds from Jericho morph. ?O O O O C O-A O O C-O ?O THH C O ?O O O O O  resorption 4 5 5 6 2-6 6 3 5 2-6 5 1 2-6 5 U 5 5 U 5  colour c/l br c/l c/l gr c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  transp. t s-t t t o t t t t t s-t s-t t t t t t t  N content (ppm) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  %B N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  Inclusions  1 gnt  eclogitic  δ13C N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A -38.44  052G(I)  O  6  c/l  t  N/A  N/A  1 gnt  eclogitic  -30.39  052G(II) 052P  ?C-O O-A  3 5  c/l c/l  t t  67 62  0 0  1 gnt  eclogitic  N/A -39.04  054B 054G 058 061 062G(I) 062G(II) 065P 073P 076G 077X(I)  O-A O O O O O O C O ?C  5 6 5 4 6 6 4 2-6 3 2-6  c/l y c/l c/l c/l c/l c/l b c/l p  t t t t t t t s-t t s-t  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  Sample ID 000X 004 009 009DD 0012D 014B 015B 020E 027 028D 030G 034P 037A 041H 042H 045P 051G(I) 051G(II)  159  Paragenesis  1 gnt 1 gnt  eclogitic eclogitic  3 gnt  eclogitic  N/A N/A -26.03 N/A N/A N/A N/A N/A -35.23 N/A  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID 077X(II) 111G 111X 113P 113X 116X(2chips) 117G 127X 135X 162G 163 165 168X 171G 172 174 176G 177G 191P 193G 199 202G 210X 247X 251X 252X 253P 255X 256X 260X 266P  morph. O M ?O U O O O O C-O THH O O-A O-A M M ?O D M O O O O-D O ?O O ?O O-A O ?O ?O ?O  resorption U 6 U 1 6 5 4-6 2-6 1-5 6 5 5 6 6 1-2 1 6 5 6 U 4 5 U 4 U 5-6 5-6 U U U  colour y c/l c/l c/l c/l c/l c/l c/l gn c/l c/l c/l c/l c/l c/l c/l br c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  transp. s-t t s-t t t t t s-t t t t t t t t s-t s-t t t t t t t t t t t t s-t s-t s-t  N content (ppm) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  160  %B N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  Inclusions  Paragenesis  1 cpx  eclogitic  1 gnt  eclogitic  2 cpx 2 cpx  eclogitic eclogitic  δ13C N/A N/A N/A N/A N/A -41.08 N/A N/A N/A N/A N/A N/A N/A -33.45 -4.17 N/A N/A N/A N/A -3.28 N/A N/A -40.30 N/A N/A N/A N/A -35.03 -39.12 N/A -38.06  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID 280X 284X 286Q 289G(I) 289G(II) 289R 290G 296Q 298G 298R 299Q 302G(I) 302G(II) 302G(III) 302Q 303Q 304QJK 305G(I) 305G(II) 305G(III) 305G(IV) 306G(I) 306G(II) 306G(III)  morph. O O-A O O O O ?O ?O O O-A O ?O O O O U OA O-A CO-A O-A O (?)O O-A O-A  resorption 6 5 4 6 5 5 U 3-6 4 5-6 5 U 3-4 4-6 3 ?1 5 5-6 5-6 5-6 5 U 6 4  colour c/l c/l y c/l p c/l y c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  transp. t t t t s-t t s-t t t t t t t t t t t t t t t s-t t t  N content (ppm) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 914 59 N/A N/A N/A N/A N/A N/A N/A  %B N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 32 11 N/A N/A N/A N/A N/A N/A N/A  306G(III) 308G(II) 308G(III) 308G(IV) 308X(I) 308X(II) 311Q  O-A ?M O O OA O ?C-O  4 5 4-6 4 5-6 5-6 U  c/l c/l c/l c/l c/l c/l c/l  t t s-t s-t t t s-t  N/A N/A N/A BDL N/A N/A N/A  N/A N/A N/A N/A N/A N/A  161  Inclusions 1 gnt 6 gnt; 2 phl 1 gnt  Paragenesis eclogitic eclogitic websteritic  2 gnt  eclogitic  3 gnt 1 gnt  eclogitic eclogitic  1 gnt  eclogitic  1 gnt  eclogitic  δ13C -36.23 -33.66 N/A -39.15 N/A -37.96 N/A N/A N/A -35.66 N/A N/A N/A N/A -35.86 -37.978 -36.33 N/A N/A N/A N/A -4.18  -29.60 -35.63  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID  morph.  resorption  colour  transp.  N content (ppm)  %B  312G 312X(I) 312X(II) 314G 314X 316G 316R 318G 319G(I) 319G(II) 319X 321G(I) 321G(II) 322X 322Z 323G 323Q(I) 323Q(II) 324P 325G 325P 325X(I) 325X(II) 326G 326X 327G 328P 328X 329G 329P 331G  O O O (?)O O O ?O ?O O ?O O U ?O O O O O-A O O O O O O O O O O ?O O C O  6 5 5 U 5 6 4-6 U 6 U 5 U U 5 5 4 5 4 4 5 4 5 5 5 4 2-5 5 U 5 2-6 6  c/l c/l c/l c/l c/l c/l c/l c/l c/l y c/l y c/l c/l c/l c/l c/l c/l c/l c/l gn/y c/l c/l c/l c/l c/l c/l c/l c/l gr c/l  t t t t t t s-t t t s-t t t t t t t t t t t t t t t t t t t t o t  151 74 N/A N/A 42 1524 47 N/A N/A N/A 189 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 49 N/A N/A N/A 64 N/A N/A N/A N/A N/A  0 0 N/A N/A 0 44 0 N/A N/A N/A 0 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 0 N/A N/A N/A 23 N/A N/A N/A N/A N/A  162  Inclusions  Paragenesis  δ13C  -4.31 -41.29 ?hem  -31.27 -24.61 -30.71 -4.83  -38.14  dia  -37.42  -3.79 -37.68  1 gnt  eclogitic  -37.42  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID  morph.  resorption  colour  transp.  N content (ppm)  %B  331G(II) 332G 332X 334G(I) 334G(II) 334X(I) 334X(II) 337G(I) 337G(II) 338R 339G 340G(I) 340G(II) 340G(III) 343P(I) 343P(II) 344P 344X 345P 346G 348X 348Q 352G 354G 355X 355Q 358G 360G 361G 362G  D M C-O O O O-A O O O O-A C-A O U O O O ?O THH C-O ?O O O O O O O O O C O  2 6 2-6 6 4-6 5 5 5 4 5 2-6 4 U 5 6 5 U 1 2-6 U 4 5 5 4 5 5 5 3-4 2-6 4-6  c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l gr c/l c/l c/l c/l c/l c/l br c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  t t s-t t s-t t t t s-t t o t s-t t t t t s-t t t s-t t t t t t t s-t s-t t  BDL N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 170 N/A N/A N/A N/A  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 0 N/A N/A N/A N/A  163  δ13C  Inclusions  Paragenesis  1 gnt  eclogitic  -35.38 -5.49  2 ol  peridotitic  -4.550 -38.08  6 gnt; 1 cpx 1 gnt  eclogitic eclogitic  -40.14 -35.16 -4.72  1 gnt  eclogitic  -37.93  Table A1. Characteristics of diamonds from Jericho (continued) morph.  resorption  colour  transp.  N content (ppm)  %B  Inclusions  O  2-3  c/l  t  N/A  N/A  2gnt ;1 opx; 2phl;  363G 363R 364G 365X 367Q(I) 367Q(II)  O-A O-A O O O-A O  5 6 4-2(n/u) 3 4 5  c/l c/l c/l c/l c/l c/l  t t t t t t  N/A N/A N/A N/A N/A N/A  N/A N/A N/A N/A N/A N/A  369P 369R 370G 371G 371Z 372G(I) 372G(II) 372G(III) 300373G 373G(II) 374G(I) 374G(II) 374(IV) 375G 376G 377G 377R(I) 377R(II) 377X 378(I) 378(II) 378G  O THH O O O OA O C-O O O (?)O ?O O ?O O O O O-A O ?O O O  5 1 5 5 5 6 5 2-6 5 5 U U 2-5 U 4 4-5 5 5 4 5 5 3  c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  t s-t t t t t t t t t t s-t t s-t s-t t t t s-t t t t  N/A N/A N/A N/A N/A N/A BDL N/A N/A N/A N/A 625 N/A N/A N/A N/A N/A N/A N/A N/A 26 N/A  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 28 N/A N/A N/A N/A N/A N/A N/A N/A 0 N/A  Sample ID  362Q  164  Paragenesis  δ13C  websteritic  -36.60  2 gnt  eclogitic  -30.99  2 cpx  eclogitic  -32.68 -41.39  phl;serp;1spl; 1ilm;1sulph  -5.22  -33.52  -4.87  3 gnt; 2 cpx;  eclogitic  -35.26 -29.74 -33.93 -33.94  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID  morph.  resorption  colour  transp.  N content (ppm)  %B  378X 379G 381P 384R 385G(I) 385G(II) 388P 389G 389P 390R 392 384R 385G(I) 385G(II) 388P 389G 389P 390R 392 392R 393G 395G(I) 395G(II) 397G 397P 399X  O THH O O O O O O O O O O O O O O O O O ?O ?M O O O THH O  4 1 5 4 5 4 4 5 6 6 3 4 5 4 4 5 6 6 3 U 5 5 5 4 1-2 4  c/l c/l c/l c/l c/l c/l y/gn c/l c/l c/l c/l c/l c/l c/l y/gn c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l c/l  t s-t t t t t tl t t t t t t t tl t t t t t t t t t s-t t  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A  401 401P(I) 401P(II)  O O O  5 4 5  c/l c/l c/l  s-t t t  N/A N/A N/A  N/A N/A N/A  165  δ13C  Inclusions  Paragenesis  2 gnt; 1 cpx  eclogitic  1 gnt 1 serp; 1 sulph 1 cpx  eclogitic  2 gnt; 1 cpx  eclogitic  1 gnt 1 serp; 1 sulph 1 cpx  eclogitic  -4.81 -39.06  eclogitic  -25.72  1 gnt; 1 cpx 1 gnt 2 gnt  eclogitic eclogitic eclogitic  -29.39 -34.30 -34.22  eclogitic websteritic  -31.35 -41.32  eclogitic eclogitic eclogitic  -35.70 -29.69 -40.74  1 gnt 5gnt;1phl; 1serp 1 gnt 1 gnt 2 gnt  -34.03  -30.10 eclogitic  Table A1. Characteristics of diamonds from Jericho (continued) Sample ID  morph.  resorption  colour  transp.  N content (ppm)  %B  Inclusions  Paragenesis  δ13C  401P(III) O-A 6 c/l t N/A N/A 405X O 6 c/l t N/A N/A 1 gnt eclogitic -32.04 414 O 5 c/l t 43 0 1 gnt eclogitic -39.55 611 O 4 c/l t N/A N/A 3 gnt eclogitic 401P(III) O-A 6 c/l t N/A N/A 405X O 6 c/l t N/A N/A 1 gnt eclogitic 414 O 5 c/l t 43 0 1 gnt eclogitic -39.55 611 O 4 c/l t N/A N/A 3 gnt eclogitic -39.12 Abbreviations: O=octahedron; M=macle; THH=tetrahexahedron; C=cube; C-O=cuboctahedron; A=aggregate; U=unknown; n/u=non uniform; c/l=colourless; y=yellow; gr=grey; gn=green; b=blue; p=pink; br=brown; transp=transparency; t=transparent; s-t=semi-tranparent; tl=translucent; o=opaque; N/A=not analyzed; BDL=below detection limit; gnt=garnet; cpx=clinopyroxene; opx=orthopyroxene; ol=olivine; phl=phlogopite; serp=serpentine; hem=hematite; spl=spinel; ilm=ilmenite; sulph=sulphide; dia=diamond  166  Table A2. Characteristics of the Wawa diamonds. Sample ID.  morph.  resorption  colour  trans parency  CL colour  N (ppm)  %B  GQE1-1  O-CA  5  CL  TL  G/Y  272  23  GQE1-2  O?  1  CL  TP  Or  66  100  GQE2-1  O-CA  5  CL  TP  O/Y  <mdl  Regularity  H peak at 1307 nm (rel. absorption units)  IR spectrum classification  0.02  Type IaAB  -  Type IaB?  79  R I N/A I  -  Type II Type IaAb  GQE2-2  O  1  CL  TL  G/Y  19  27  N/A  0.05  GQE2-3  O-CA  5  CL  TP  G/Y  <mdl  89  R  -  Type II  GQE2-4  C-O  3  CL  TP  G/Y  81  23  R  -  Type IaAB  GQE3-1  C  4  Y  TL  Or  <mdl  -  R  -  Type IaA  GQE4-1  U  2  BL  Op  Or/P  N/A  -  N/A  -  -  GQE4-2  O  5  CL  TP  Or  95  59  R  -  Type IaAB?  GQE4-3  O-C  5  Y/BL  TL/Op  Or  N/A  -  I  -  -  GQE4-4  O-C  4  Y/BL  TL/Op  Or  311  88  I  -  -  GQE4-5  C  5  Y  TL  Or/Y  289  46  I  -  Type IaAB  GQE4-6  O  1  BL  Op  Or/G  N/A  -  I  -  -  GQE4-7  O-CA  5  CL  TP  Y  <mdl  -  N/A  -  Type II  GQE4-8  O-CA  4  CL  TP  Y  <mdl  -  N/A  -  -  GQE4-9  O  4  CL  TL  G  <mdl  -  N/A  -  GQE4-10  O-C  4  Y/BL  TL/Op  Or/P  <mdl  -  I  -  -  GQE4-11  C  5  Y  TL  Or  251  14  I  -  Type IaAB  GQE4-12  O-C  4  C/BL  Op  Or/Y/G  N/A  -  I  -  -  GQE4-13  O-C  5  C/BL  Op  Or/G  N/A  -  I  -  -  GQE4-14  O-CA  5  Y  TP  Or/P  129  21  R  -  Type IaAB  GQE4-15  O  5  BL/W  Op  Or/Y  N/A  -  R  -  -  GQE4-16  O-C  5  Y/BL  Op  Or/G  N/A  -  N/A  -  -  GQE4-17  O  5  CL  TL  Or  N/A  -  N/A  -  -  GQE4-18  O-C  2  Y/BL  TL/Op  Or/G  50  91  I  -  Type IaAB  GQE4-19  O  5  CL  TL  Y  100  100  R  -  Type IaB?  GQE5-1  O-CA  5  CL  TP  Y  N/A  -  R  -  -  GQE5-2 GQE5-3  M O-CA  5 6  CL CL  TP TP  Y G/Y  197 164  85 25  N/A I  0.06 -  Type IaAB Type IaAB  167  Inclusions Paragenesis Primary  Secondary  2 Ol  1 Ol, 2 Cpx 1 Ol, 1 Cpx,  peridotitic  1 Ap, 1 Bt, 1Chl  mixed  1 Al-Sil.  mixed  1 Al-Sil.  4 Chl 1An, 1Cpx,  1 Al-Sil.  eclogitic  Table A2. Characteristics of the Wawa diamonds (continued) Sample No.  Morph.  Resorption  Colour  Trans parency  CL Colour  N (ppm)  %B  Regularity  H peak at 1307 nm (rel. absorption units)  IR spectrum classification  GQE5-4  O-CA  5  CL  TP  Or/Y  N/A  -  R  -  -  GQE6-1  O-CA  4  CL  TL  Or  138  69  N/A  0.08  Type IaAB  GQE7-1  O-CA  4  BR  TP  P/Y  <mdl  -  N/A  -  Type II  GQE8-1  O-C  5  CL/GY  TL/Op  Or  N/A  GQE8-2  U-C  U  CL/GY/BL  Op  Y/Or/P  <mdl  N/A  -  -  -  I  -  Type II  GQE8-3  U  5  CL/GY/BL  Op  G/Y  N/A  R  -  -  GQE8-4  O-C  U  CL/GY/BL  TL/Op  G  <mdl  -  R  -  Type II  GQE9-1  O-CA  U  BR  TL  Or/Y  421  12  I  -  Type IaAB  GQE10-1  O  1  BR  TL  G/Y/Or  66  63  R  0.01  Type IaAB  GQE10-2  O  5  CL  TP  G/Or  145  100  N/A  0.10  Type IaB?  GQE10-3  O-CA  2  GY  TL  Y  101  58  I  -  Type IaAB?  GQE10-4  O  2  CL/BL  TL  G  262  0  N/A  -  Type IaA  GQE11-1  O  6  C  TP  Or/G  N/A  -  N/A  -  Type IaA  GQE11-2  O  4  C  TL  Or/Y  N/A  -  N/A  -  -  GQE12-1  O-C  U  CL/BL  TL/Op  Or  168  67  N/A  -  -  GQE13-1  O  3  Y/GY  Op  G/Y  20  0  N/A  -  -  GQE13-2  O  3  BR  TL  Or  <mdl  -  N/A  -  Type II  GQE13-3  O  5  GY  TL  Or  20  100  N/A  -  Type II? Type IaAB  Inclusions Paragenesis Primary  Secondary  1Al-Sil., 2 Chl,1 NaMg Sil.  1 Bt  3 Bt, 1 NaMg Sil. 1 Ol, 2 Opx, 1 Cpx,  2 Chl  1 Al-Sil.  1 Ni-Fe Sulph., 1 An  peridotitc or eclogitic  GQE13-4  C-CA  4  Y  TL  Or  62  80  N/A  -  GQE13-5  C-O/A  5  Y/OR  TL/Op  Or  66  0  N/A  -  Type IaA  GQE14-1  C-O/A  4  Y/GY  TL/Op  Or  49  0  N/A  -  Type IaA?  2 Chl  GQE14-2  O  U  GY/CL  TL/Op  Or  13  0  N/A  -  Type II  1 Chl  168  mixed  Table A2. Characteristics of the Wawa diamonds (continued) Sample No.  Morph.  Resorption  Colour  Trans parency  CL Colour  N (ppm)  %B  Regularity  H peak at 1307 nm (rel. absorption units)  IR spectrum classification  GQE14-3  O-CA  6  CL  TP  Or  740  90  N/A  0.21  Type IaAB  GQE14-4  C-CA  4  Y  TL  Or  96  0  N/A  -  Type IaA  GQE15-1  O  5  CL  TP  Or  <mdl  -  N/A  -  Type II  GQE16-1  O  5  CL  TP  Or/G  <mdl  -  N/A  -  Type II  GQE16-2  M  1  CL  TL  Y  N/A  -  N/A  -  Type II  GQE16-3  O-CA  4  BR  TP  Y/Or  132  94  N/A  0.10  Type IaAB  GQE16-4  O  5  CL  TP  Or  277  29  N/A  -  Type IaAB  GQE17-1  O-CA  4  CL  TP  G  246  8  N/A  -  Type IaAB  GQE17-2  M  5  CL  TP  Or  55  77  N/A  -  Type IaAB?  GQE17-3  C-O  1  CL  TL  Or  70  0  N/A  -  Type IaA  GQE17-4  O  4  CL  TP  Or  0  0  N/A  -  Type II  GQE17-5  O  U  CL/BL  Op  N/A  81  100  N/A  -  Type IaB  GQE18-1  C-CA  4  Y  Op  N/A  25  100  N/A  -  Type IaB?  KD3652  O  5  CL  TP  N/A  105  0  N/A  -  Type IaA  KD3653  O  4  CL  TP  N/A  N/A  -  N/A  -  -  KD3656-2  C  5/4  Y  TL  N/A  N/A  -  N/A  -  Type IaA  KD3668-1  O-CA  6/5  BR  TP  N/A  177  0  N/A  -  KD4214-1  O-CA  5/4  CL  TP  N/A  <mdl  -  N/A  -  -  KD4220-1  C  4  Y  TP  N/A  946  0  N/A  -  Type IaA  KD4224-1  M  4  CL  TP  N/A  63  0  N/A  -  Type IaA  KD4226-1  C-O  6  BR  TP  N/A  240  0  N/A  -  Type IaA  KD4239-2  O-CA  4/3  CL  TP  N/A  N/A  -  N/A  -  -  KD4229-2  O-CA  4  CL  TP  N/A  434  0  N/A  -  Type IaA  KD4234-1  M  5/4  CL  TP  N/A  <mdl  -  N/A  -  -  169  Inclusions Paragenesis Primary  Secondary  4 Ol, 2 Cpx, 2 NiFe Sulph  1 K-Ni-Fe Sulph, 1 Bt, 5 Chl  mixed  3 Chl, 1 Ap 4 Ol, 1 Opx, 1 Ab  1 Fe-Al Sil., 1 K Fsp.  peridotitic  Table A2. Characteristics of the Wawa diamonds (continued) Morph.  Resorption  Colour  Trans parency  CL Colour  N (ppm)  %B  Regularity  KD4234-2  O  5/4  CL  TP  N/A  198  0  N/A  H peak at 1307 nm (rel. absorption units) -  KD4243-1  M  5  CL  TP  N/A  334  0  N/A  -  Type IaA  KD4231-1  O  3  BR  TP  N/A  686  0  N/A  -  Type IaA  KD4237-1  O-CA  3  CL  TP  N/A  444  0  N/A  -  Type IaA  KD4220-2  O  1  CL  TP  N/A  N/A  -  N/A  -  -  Sample No.  IR spectrum classification  Inclusions  Paragenesis  Type IaA 3 Ol, 1An  peridotitic  2 Ol  peridotitic  Abbreviations: O=octahedral; C=cubic; A=aggregate; M=macle; U=unknown; CL=colorless; BL=black; BR=brown; Y=yellow; GY=grey; TP=transparent; TL=translucent; Op=opaque; G=green; Or=orange; P=pink; B=blue; < mdl= below minimum detection limit; N/A= not analyzed; R=regular; I=irregular Ol=olivine; Opx=orthopyroxene; Cpx=clinopyroxene; Bt=biotite; Chl=chlorite; Ab=albite; An= anorthite; Fsp=feldspar Ap=apatite; Sil.=silicate; Sulph.=sulphide. 1 Resorption classes were determined according to the classification scheme of McCallum et al., (1994), which describes the degree of resorption from conversion of octahedral diamond to a tetrahexahedroid. The data collected in this study is highlighted in yellow. All the remaining data was collected by Lefebvre (2004).  170  Appendix B. Analytical precision tables  171  Table B1. Precision of EPMA of polished mineral inclusions in Jericho diamonds at the 95% confidence level (values expressed in wt%) garnet clinopyroxene orthopyroxene olivine hematite phlogopite spinel mineral 1 2 1 2 1 2 1 2 1 2 1 2 MDL 2σ MDL 2σ MDL 2σ MDL 2σ MDL 2σ MDL 2σ MDL1 2σ2 statistic  No. of analyses SiO2 TiO2 Al2O3 Cr2O3 FeO Fe2O3 MnO NiO MgO CaO BaO Na2O K2O  46  7  1  2  1  4  0.03 0.07 0.02 0.06 0.02 0.06 0.03 0.07 0.04 0.08 0.04 0.11 0.06 0.05 0.04 0.05 0.04 0.05 0.04 0.05 0.05 0.06 0.04 0.05 0.08 0.06 0.06 0.06 0.06 0.06 0.05 0.05 0.05 0.05 0.03 0.07 0.11 0.16 0.12 016 0.12 0.16 0.12 0.17 0.10 0.16 0.10 0.16 0.10 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.14 0.25 0.10 0.10 0.09 0.09 0.07 0.09 0.07 0.09 0.07 0.10 0.07 0.09 0.06 0.07 0.10 0.12 0.10 0.13 0.10 0.13 0.11 0.10 0.10 0.11 0.11 0.05 0.12 0.04 0.12 0.04 0.12 0.04 0.10 0.05 0.12 0.05 0.12 0.05 0.09 0.05 0.09 0.05 0.09 0.06 0.05 0.05 006 0.05 0.10 0.07 0.04 0.03 0.05 0.04 0.05 0.04 0.05 0.04 0.05 0.04 0.08 0.04 0.04 0.04 0.04 0.04 0.07 0.16 1 Minimum Detection Limit 2 Precision at 95% confidence level. MDLs and analytical precision (2σ) for the analyzed elements (wt%) were calculated by the EMP XmasPlus software.  172  ilmenite MDL1 2σ2  1 0.03 0.05 0.05 0.10 0.10 0.07 0.10 0.10 0.05 0.05 -  millerite MDL1 2σ2  1 0.08 0.06 0.05 0.16 0.10 0.08 0.10 0.05 0.05 0.04 -  0.03 0.05 0.05 0.10 0.10 007 0.10 0.10 0.05 0.05 -  2  0.08 0.05 0.05 0.16 0.10 0.08 0.10 0.05 0.05 0.04 -  Fe Mn Co Cu  0.40 0.03 0.05 0.05  0.05 0.04 0.05 0.05  Ni  0.19  0.05  Table B2. Precision of EMPA of unpolished mineral inclusions in Jericho diamonds at the 95% confidence level (values expressed in wt%) clinopyroxene orthopyroxene olivine albite Fe-Ni Sulphide mineral 1 2 1 2 1 2 1 2 MDL 2σ MDL 2σ MDL 2σ MDL 2σ MDL1 2σ2 statistic  No. of analyses SiO2 TiO2 Al2O3 Cr2O3 FeO Fe2O3 MnO NiO MgO CaO Na2O K2O  1 0.02 0.04 0.06 0.12 0.08 0.07 0.10 0.12 0.09 0.05 0.04  1 0.06 0.05 0.06 016 0.08 0.09 0.13 0.04 0.05 0.04 0.04  0.02 0.04 0.06 0.12 0.08 0.07 0.10 0.12 0.09 0.05 -  3 0.06 0.05 0.06 0.16 0.08 0.09 0.13 0.04 0.05 0.04 -  0.03 0.04 0.05 0.12 0.08 0.07 0.11 0.12 0.09 0.05 -  1 0.07 0.05 0.05 0.17 0.08 0.10 0.10 0.04 0.06 0.04 -  0.02 0.04 0.06 0.13 0.07 0.04 0.04 0.06 0.04  3 0.15 0.05 0.05 0.16 0.08 0.06 0.04 0.08 0.04  1  1  Fe Mn Co Cu  0.40 0.03 0.05 0.05  0.05 0.04 0.05 0.05  Ni  0.19  0.05  Minimum Detection Limit Precision at 95% confidence level MDLs and analytical precision (2σ) for the analyzed elements (wt%) were calculated by the EMP XmasPlus software.  2  173  Appendix C. Major and trace element chemistry of garnets and clinopyroxenes in eclogitic xenoliths from the Jericho kimberlite  174  Table C1. Major element chemistry of minerals from Jericho diamondiferous eclogites Sample ID 131-I 20-Lupin 21-Lupin 135-F*-1 135-F*-3 Mineral clinopyroxene clinopyroxene clinopyroxene clinopyroxene clinopyroxene  135-F*-4 clinopyroxene  135-F*-5 clinopyroxene  135-F*-6 clinopyroxene  135-F*-7 clinopyroxene  SiO2  53.46  53.95  55.43  53.53  54.22  53.58  54.07  53.31  53.65  TiO2  0.16  0.18  0.31  0.12  0.11  0.14  0.16  0.18  0.18  Al2O3  2.10  2.05  10.72  2.09  2.82  2.21  2.59  2.24  2.30  Cr2O3 FeO MnO MgO CaO  0.27 2.83 0.12 16.77 21.21  0.24 2.73 0.11 16.82 20.83  0.13 2.55 0.05 10.13 14.64  0.15 2.75 0.08 16.97 21.14  0.24 2.27 0.07 16.58 20.85  0.11 2.82 0.14 16.88 21.01  0.17 2.68 0.07 16.63 20.78  0.14 3.20 0.08 16.68 20.70  0.21 2.78 0.09 16.72 20.64  Na2O  1.46  1.32  5.08  1.13  1.38  1.18  1.28  1.20  1.23  K 2O Mg# Total  91 98.38  92 98.24  88 99.04  92 97.96  93 98.54  91 98.07  92 98.43  90 97.73  91 97.80  Sample ID Mineral  123-F* clinopyroxene  LGS017MX14 garnet  131-I garnet  20-Lupin garnet  21-Lupin garnet  135-F*-1 garnet  135-F*-3 garnet  135-F*-4 garnet  135-F*-5 garnet  SiO2  54.19  40.93  40.98  41.49  40.02  41.10  41.20  40.78  40.66  TiO2  0.16  0.16  0.22  0.19  0.34  0.25  0.10  0.22  0.20  Al2O3  2.10  23.29  23.47  23.67  23.21  23.68  23.71  23.54  23.44  Cr2O3 FeO MnO MgO CaO  0.30 2.69 0.06 16.98 20.84  0.30 10.86 0.38 19.60 4.05  0.33 10.10 0.38 19.92 4.13  0.42 10.23 0.36 19.99 4.17  0.19 12.40 0.18 13.55 10.24  0.34 10.67 0.46 20.16 4.21  0.52 8.75 0.41 21.19 4.16  0.45 10.41 0.38 20.36 4.16  0.33 10.35 0.41 20.22 4.07  Na2O  1.49  0.05  0.05  0.04  0.10  0.04  0.04  0.03  0.03  K 2O Mg# Total  92 98.81  76 99.61  78 99.58  78 100.55  66 100.21  77 100.91  81 100.08  78 100.33  78 99.71  175  Table C1. Major element chemistry of minerals from Jericho diamondiferous eclogites (continued) Sample ID 135-F*-6 135-F*-7 131* 123-F* 132* 109* Mineral garnet garnet garnet garnet garnet garnet  LGS017MX14 clinopyroxene  SiO2  41.22  40.98  40.98  41.20  41.42  40.90  53.38  TiO2  0.22  0.21  0.22  0.20  0.20  0.15  0.65  Al2O3  23.44  23.57  23.47  23.30  23.55  23.27  2.10  Cr2O3 FeO MnO MgO CaO  0.28 11.45 0.37 19.56 4.14  0.40 10.29 0.41 20.35 4.07  0.33 10.10 0.38 19.92 4.13  0.39 9.97 0.36 20.12 4.09  0.45 10.21 0.37 20.05 4.14  0.29 10.91 0.38 19.60 4.06  0.16 2.94 0.07 16.92 21.04  Na2O  0.04  0.05  0.05  0.05  0.04  0.05  1.45  K2O Mg# Total  75 100.72  78 100.33  78 99.58  78 99.68  78 100.43  76 99.61  91 98.71  176  Table C2. Major element chemistry of primary and secondary minerals from massive and foliated Jericho eclogites Sample ID 6-11(massive) 55-4 (massive) 47-8(foliated) Average of 6 5 5 1 12 1 1 10 Mineral cpx, prim. cpx, prim. cpx, prim. cpx, sec cpx, prim. cpx, sec cpx, sec gar, prim.  1 gar, sec.  1 gar, sec.  SiO2  54.21  52.20  55.57  49.20  55.06  51.82  51.09  38.08  39.39  39.32  TiO2  0.08  0.51  0.30  2.29  0.16  0.84  0.97  0.10  0.33  0.40  Al2O3  2.55  1.31  9.24  9.03  9.83  1.88  2.34  21.84  22.43  22.51  Cr2O3 FeO MnO MgO CaO Na2O  0.03 6.97 0.09 13.97 19.45 1.91  0.03 7.02 0.14 14.91 21.11 0.91  0.04 4.03 0.04 10.59 15.15 5.49  0.02 6.26 0.16 11.00 19.91 2.48  0.06 7.00 0.03 8.25 13.36 6.16  0.16 8.70 0.19 14.08 21.28 0.91  0.12 8.19 0.22 13.86 21.32 0.98  0.04 25.45 0.48 6.01 8.31 0.05  0.03 19.88 0.50 11.02 6.51 0.07  0.03 19.69 0.42 11.47 6.36 0.04  K2O Mg# Total  0.02 0.78 99.28  0.02 0.79 98.95  0.02 0.82 100.47  0.76 100.41  0.01 0.68 99.91  0.02 0.74 99.88  0.01 0.75 99.11  0.30 100.36  0.50 100.17  0.51 100.25  Sample ID Average of Mineral  47-2 (massive) 8 1 cpx, prim. cpx, sec.  52-5 (foliated) 5 5 gar, prim. gar, sec  JDF6NEcl(foliated) 11 1 cpx, prim cpx, sec.  20-7 (foliated) 16 1 cpx, prim cpx, sec.  SiO2  55.43  54.66  40.51  40.89  55.78  54.58  55.21  53.92  TiO2  0.12  0.35  0.27  0.26  0.12  0.16  0.11  0.14  Al2O3  7.46  4.05  23.31  23.49  11.32  9.23  6.68  3.40  Cr2O3 FeO MnO MgO CaO Na2O  0.07 4.81 0.03 11.55 17.01 4.23  0.11 4.62 0.08 16.08 18.26 2.20  0.17 13.41 0.24 14.73 7.48 0.10  0.14 13.55 0.31 16.89 4.75 0.09  0.12 3.89 0.03 9.15 14.05 6.02  0.13 4.36 0.06 10.82 16.59 4.71  0.07 4.54 0.04 12.11 17.54 3.91  0.12 5.52 0.06 14.59 21.10 1.63  0.01 0.01 0.01 K 2O Mg# 0.81 0.86 0.66 0.69 0.81 Total 100.70 100.42 100.21 100.37 100.49 Abbreviations: gar=garnet; cpx=clinopyroxene; prim=primary; sec.=secondary  0.02 0.82 100.66  0.01 0.83 100.22  0.01 0.82 100.48  177  Table C3. Trace element chemistry of garnets and clinopyroxenes from the Jericho eclogites. All values in ppm (unless otherwise indicated) Sample ID  42-3  47-8  Mineral  Garnet  Cpx  Reconstructed bulk composition Gar 32% Cpx 68%  Garnet  Cpx, prim.  Cpx, sec.  Reconstructed bulk composition Gar 30% Cpx 70%  Average of  2  2  1  2  2  2  1  Sc  52.21  28.99  36.42  57.96  34.71  60.62  41.68  TiO2 (wt%)  0.12  0.22  0.19  0.17  0.24  0.40  0.21  V  88.16  316.42  243.38  202.33  644.12  1178.99  511.58  Cr  445.80  462.40  457.09  171.64  199.51  368.83  191.15  33.28  60.34  38.79  Co  52.82  26.19  34.71  51.63  Rb  0.00  0.00  0.00  0.00  0.67  12.17  0.47  Sr  0.38  495.62  337.14  0.47  280.00  405.86  196.14  Y  45.17  2.53  16.17  36.98  1.29  2.30  11.99  Zr  6.83  12.34  10.58  7.55  12.01  18.59  10.67  Nb  0.00  0.08  0.06  0.00  0.16  2.28  0.11  Ba  0.02  0.15  0.11  0.00  0.55  17.50  0.38  La  0.00  1.56  1.06  0.01  1.54  4.39  1.08  Ce  0.07  6.63  4.53  0.18  5.57  11.37  3.96  Pr  0.05  1.42  0.98  0.10  1.03  1.88  0.75  Nd  0.76  8.06  5.73  1.62  6.41  9.65  4.97  Sm  1.44  2.24  1.99  2.28  1.49  2.50  1.73  Eu  0.97  0.77  0.84  1.52  0.55  0.82  0.84  Gd  3.74  1.66  2.32  4.82  0.99  1.49  2.14  Tb  0.95  0.17  0.42  1.01  0.10  0.18  0.37  Dy  7.41  0.86  2.96  6.90  0.40  0.68  2.35  0.06  0.10  0.49  Ho  1.78  0.11  0.65  1.49  Er  5.91  0.21  2.03  4.26  0.12  0.20  1.36  Tm  0.90  0.02  0.30  0.61  0.01  0.02  0.19  Yb  6.31  0.11  2.10  4.01  0.03  0.10  1.22  Lu  1.03  0.02  0.35  0.63  0.00  0.01  0.19  Hf  0.11  1.33  0.94  0.13  0.92  1.38  0.69  Pb  0.00  1.68  1.14  0.00  1.27  0.99  0.89  Th  0.00  0.09  0.06  0.00  0.03  0.20  0.02  U  0.00  0.01  0.01  0.00  0.03  0.10  0.02  P2O5  0.05  0.00  0.02  0.04  0.00  0.03  0.01  178  Table C3. Trace element chemistry of garnets and clinopyroxenes from the Jericho eclogites (continued). All values in ppm (unless otherwise indicated) Sample ID  55-4  6NEcl Reconstructed bulk composition Gar 39% Cpx 61%  Garnet  Cpx  Reconstructed bulk composition Gar 53% Cpx 47%  2  2  1  2  2  1  Sc  58.59  12.30  36.63  123.42  53.74  80.78  TiO2 (wt%)  0.31  0.27  0.29  0.15  0.28  0.23  V  119.34  225.42  169.66  188.20  714.84  510.50  Cr  385.09  178.34  287.01  683.92  634.48  653.66  Co  57.04  17.90  38.47  129.87  52.69  82.63  Rb  0.00  0.00  0.00  0.00  0.00  0.00  Sr  0.54  86.35  41.25  0.51  878.18  537.64  Y  23.73  0.53  12.73  32.09  1.81  13.56  Zr  30.59  24.05  27.49  10.73  42.18  29.97  Nb  0.17  0.14  0.16  0.00  0.00  0.00  Ba  0.00  0.05  0.02  0.02  0.21  0.13  La  0.03  0.74  0.37  0.00  1.99  1.21  Ce  0.42  2.92  1.61  0.08  8.94  5.50  Pr  0.20  0.55  0.37  0.07  2.25  1.40  Nd  2.19  2.79  2.48  1.14  13.78  8.87  Sm  2.07  0.64  1.39  1.46  2.85  2.31  Eu  1.07  0.20  0.65  1.16  1.06  1.10  Gd  3.79  0.44  2.20  2.99  1.63  2.16  Tb  0.84  0.05  0.47  0.71  0.15  0.36  Dy  5.04  0.22  2.75  5.47  0.66  2.52  Ho  1.00  0.02  0.53  1.33  0.08  0.56  Er  2.65  0.05  1.41  4.48  0.14  1.82  Tm  0.35  0.00  0.19  0.69  0.02  0.28  Yb  2.23  0.03  1.19  5.11  0.09  2.03  Lu  0.34  0.00  0.18  0.90  0.00  0.35  Hf  0.47  1.72  1.07  0.14  2.22  1.41  Pb  0.00  0.21  0.10  0.00  1.46  0.89  Th  0.01  0.00  0.01  0.02  0.11  0.07  U  0.01  0.00  0.00  0.00  0.00  0.00  P2O5  0.05  0.01  0.03  0.08  0.00  0.03  Mineral Average of  179  Garnet  Cpx  Table C3. Trace element chemistry of garnets and clinopyroxenes from the Jericho eclogites (continued). All values in ppm (unless otherwise indicated) Sample ID  20-7  47-2  Mineral  Gar prim.  Gar sec.  Cpx  Reconstructed bulk composition Gar 50% Cpx 50%  Average of  1  1  2  1  2  2  1  Sc  51.63  51.21  21.19  34.25  66.68  27.88  21.37  TiO2 (wt%)  0.11  0.15  0.20  0.16  0.13  0.20  0.14  V  92.16  122.54  341.56  222.77  101.19  316.20  222.24  Cr  319.43  364.83  331.87  324.49  463.00  360.75  264.21  Co  63.75  70.39  29.49  44.48  69.40  34.08  25.75  Rb  0.00  0.65  0.00  0.15  0.00  0.00  0.00  Sr  0.79  1.47  846.91  424.79  0.52  539.43  373.84  Y  40.16  40.94  1.74  19.17  31.79  1.24  1.84  Zr  3.57  13.85  8.30  8.18  7.03  10.82  7.71  Nb  0.00  0.06  0.00  0.01  0.00  0.00  0.00  Ba  0.00  3.14  0.34  0.88  0.00  0.10  0.07  La  0.01  0.26  1.45  0.78  0.00  1.24  0.86  Ce  0.10  0.50  6.61  3.44  0.09  5.30  3.68  Pr  0.08  0.12  1.57  0.83  0.06  1.14  0.79  Nd  1.40  1.96  9.92  5.74  0.94  6.63  4.62  Sm  2.48  2.74  3.17  2.71  1.76  1.85  1.34  Eu  1.61  1.56  0.93  1.14  1.13  0.59  0.44  Gd  5.75  5.42  1.82  3.27  3.94  1.07  0.86  Tb  1.13  1.07  0.16  0.57  0.88  0.12  0.11  Dy  7.94  8.11  0.68  3.89  6.05  0.47  0.51  Ho  1.69  1.73  0.08  0.81  1.34  0.06  0.08  Er  4.70  4.95  0.13  2.30  3.93  0.05  0.15  Tm  0.69  0.70  0.02  0.31  0.57  0.00  0.02  Yb  4.44  4.44  0.04  1.92  3.92  0.01  0.13  Lu  0.66  0.69  0.00  0.30  0.57  0.00  0.02  Hf  0.04  0.33  0.71  0.45  0.09  1.06  0.74  Pb  0.00  0.04  1.47  0.75  0.00  0.61  0.42  Th  0.33  0.18  0.05  0.06  0.00  0.07  0.05  U  0.00  0.01  0.02  0.01  0.00  0.01  0.01  P2O5  0.06  0.08  0.01  0.03  0.03  0.00  0.00  180  Garnet  Cpx  Reconstructed bulk composition Gar 31% Cpx 69%  Table C3. Trace element chemistry of garnets and clinopyroxenes from the Jericho eclogites (continued). All values in ppm (unless otherwise indicated) Sample ID  6-11  Mineral  Garnet  Cpx  Reconstructed bulk composition Gar 23% Cpx 77%  Average of  2  2  1  Sc  97.51  47.94  59.35  TiO2 (wt%)  0.11  0.15  0.14  V  257.99  440.50  398.51  Cr  483.70  234.98  292.20  Co  66.50  42.28  47.85  Rb  0.00  0.00  0.00  Sr  0.18  503.65  387.82  Y  70.41  6.08  20.88  Zr  7.72  20.95  17.91  Nb  0.00  0.00  0.00  Ba  0.02  8.15  6.28  La  0.01  4.11  3.17  Ce  0.10  19.75  15.23  Pr  0.07  4.10  3.17  Nd  1.10  21.96  17.16  Sm  1.89  5.49  4.66  Eu  1.12  1.66  1.54  Gd  5.33  4.25  4.50  Tb  1.44  0.52  0.73  Dy  11.98  2.11  4.38  Ho  2.96  0.27  0.89  Er  9.04  0.47  2.44  Tm  1.25  0.04  0.32  Yb  7.64  0.18  1.90  Lu  1.16  0.01  0.27  Hf  0.20  1.35  1.09  Pb  0.29  1.64  1.33  Th  0.00  0.01  0.01  U  0.00  0.00  0.00  P2O5  0.04  0.00  0.01  181  Appendix D. Permissions of use of copyrighted material  182  ELSEVIER LICENSE TERMS AND CONDITIONS Apr 11, 2011 This is a License Agreement between Andrea De Stefano ("You") and Elsevier ("Elsevier") provided by Copyright Clearance Center ("CCC"). The license consists of your order details, the terms and conditions provided by Elsevier, and the payment terms and conditions. All payments must be made in full to CCC. For payment instructions, please see information listed at the bottom of this form. Supplier Elsevier Limited The Boulevard,Langford Lane Kidlington,Oxford,OX5 1GB,UK Registered Company Number 1982084 Customer name Andrea De Stefano Customer address 905 4th Avenue New Westminster, BC V3M 1T1 License number 2645990871817 License date Apr 11, 2011 Licensed content publisher Elsevier Licensed content publication Ore Geology Reviews Licensed content title The origin of cratonic diamonds — Constraints from mineral inclusions Licensed content author T. Stachel, J.W. Harris Licensed content date September 2008 Licensed content volume number 34 Licensed content issue number 1-2 Number of pages 28 Start Page 5 End Page 32 Type of Use reuse in a thesis/dissertation Portion figures/tables/illustrations Number of figures/tables/illustrations 1 Format electronic Are you the author of this Elsevier article? No Will you be translating? No Order reference number Title of your thesis/dissertation Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds Expected completion date Apr 2011 Estimated size (number of pages) 178 Elsevier VAT number GB 494 6272 12 Permissions price 0.00 USD VAT/Local Sales Tax 0.0 USD / 0.0 GBP Total 0.00 USD  183  Terms and Conditions INTRODUCTION 1. The publisher for this copyrighted material is Elsevier. By clicking "accept" in connection with completing this licensing transaction, you agree that the following terms and conditions apply to this transaction (along with the Billing and Payment terms and conditions established by Copyright Clearance Center, Inc. ("CCC"), at the time that you opened your Rightslink account and that are available at any time at http://myaccount.copyright.com). GENERAL TERMS 2. Elsevier hereby grants you permission to reproduce the aforementioned material subject to the terms and conditions indicated. 3. Acknowledgement: If any part of the material to be used (for example, figures) has appeared in our publication with credit or acknowledgement to another source, permission must also be sought from that source. If such permission is not obtained then that material may not be included in your publication/copies. Suitable acknowledgement to the source must be made, either as a footnote or in a reference list at the end of your publication, as follows: “Reprinted from Publication title, Vol /edition number, Author(s), Title of article / title of chapter, Pages No., Copyright (Year), with permission from Elsevier [OR APPLICABLE SOCIETY COPYRIGHT OWNER].” Also Lancet special credit - “Reprinted from The Lancet, Vol. number, Author(s), Title of article, Pages No., Copyright (Year), with permission from Elsevier.” 4. Reproduction of this material is confined to the purpose and/or media for which permission is hereby given. 5. Altering/Modifying Material: Not Permitted. However figures and illustrations may be altered/adapted minimally to serve your work. Any other abbreviations, additions, deletions and/or any other alterations shall be made only with prior written authorization of Elsevier Ltd. (Please contact Elsevier at permissions@elsevier.com) 6. If the permission fee for the requested use of our material is waived in this instance, please be advised that your future requests for Elsevier materials may attract a fee. 7. Reservation of Rights: Publisher reserves all rights not specifically granted in the combination of (i) the license details provided by you and accepted in the course of this licensing transaction, (ii) these terms and conditions and (iii) CCC's Billing and Payment terms and conditions. 8. License Contingent Upon Payment: While you may exercise the rights licensed immediately upon issuance of the license at the end of the licensing process for the transaction, provided that you have disclosed complete and accurate details of your proposed use, no license is finally effective unless and until full payment is received from you (either by publisher or by CCC) as provided in CCC's Billing and Payment terms and conditions. If full payment is not received on a timely basis, then any license preliminarily granted shall be deemed automatically revoked and shall be void as if never granted. Further, in the event that you breach any of these terms and conditions or any of CCC's Billing and Payment terms and conditions, the license is automatically revoked and shall be void as if never granted. Use of materials as described in a revoked license, as well as any use of the materials beyond the scope of an unrevoked license, may constitute copyright infringement and publisher reserves the right to take any and all action to protect its copyright in the materials. 9. Warranties: Publisher makes no representations or warranties with respect to the licensed material.  184  10. Indemnity: You hereby indemnify and agree to hold harmless publisher and CCC, and their respective officers, directors, employees and agents, from and against any and all claims arising out of your use of the licensed material other than as specifically authorized pursuant to this license. 11. No Transfer of License: This license is personal to you and may not be sublicensed, assigned, or transferred by you to any other person without publisher's written permission. 12. No Amendment Except in Writing: This license may not be amended except in a writing signed by both parties (or, in the case of publisher, by CCC on publisher's behalf). 13. Objection to Contrary Terms: Publisher hereby objects to any terms contained in any purchase order, acknowledgment, check endorsement or other writing prepared by you, which terms are inconsistent with these terms and conditions or CCC's Billing and Payment terms and conditions. These terms and conditions, together with CCC's Billing and Payment terms and conditions (which are incorporated herein), comprise the entire agreement between you and publisher (and CCC) concerning this licensing transaction. In the event of any conflict between your obligations established by these terms and conditions and those established by CCC's Billing and Payment terms and conditions, these terms and conditions shall control. 14. Revocation: Elsevier or Copyright Clearance Center may deny the permissions described in this License at their sole discretion, for any reason or no reason, with a full refund payable to you. Notice of such denial will be made using the contact information provided by you. Failure to receive such notice will not alter or invalidate the denial. In no event will Elsevier or Copyright Clearance Center be responsible or liable for any costs, expenses or damage incurred by you as a result of a denial of your permission request, other than a refund of the amount(s) paid by you to Elsevier and/or Copyright Clearance Center for denied permissions. LIMITED LICENSE The following terms and conditions apply only to specific license types: 15. Translation: This permission is granted for non-exclusive world English rights only unless your license was granted for translation rights. If you licensed translation rights you may only translate this content into the languages you requested. A professional translator must perform all translations and reproduce the content word for word preserving the integrity of the article. If this license is to re-use 1 or 2 figures then permission is granted for non-exclusive world rights in all languages. 16. Website: The following terms and conditions apply to electronic reserve and author websites: Electronic reserve: If licensed material is to be posted to website, the web site is to be passwordprotected and made available only to bona fide students registered on a relevant course if: This license was made in connection with a course, This permission is granted for 1 year only. You may obtain a license for future website posting, All content posted to the web site must maintain the copyright information line on the bottom of each image, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx or the Elsevier homepage for books at http://www.elsevier.com, and Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 17. Author website for journals with the following additional clauses: All content posted to the web site must maintain the copyright information line on the bottom of each image, and the permission granted is limited to the personal version of your paper. You are not  185  allowed to download and post the published electronic version of your article (whether PDF or HTML, proof or final version), nor may you scan the printed edition to create an electronic version, A hypertext must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx , As part of our normal production process, you will receive an e-mail notice when your article appears on Elsevier’s online service ScienceDirect (www.sciencedirect.com). That e-mail will include the article’s Digital Object Identifier (DOI). This number provides the electronic link to the published article and should be included in the posting of your personal version. We ask that you wait until you receive this e-mail and have the DOI to do any posting. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 18. Author website for books with the following additional clauses: Authors are permitted to place a brief summary of their work online only. A hyper-text must be included to the Elsevier homepage at http://www.elsevier.com All content posted to the web site must maintain the copyright information line on the bottom of each image. You are not allowed to download and post the published electronic version of your chapter, nor may you scan the printed edition to create an electronic version. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 19. Website (regular and for author): A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx. or for books to the Elsevier homepage at http://www.elsevier.com 20. Thesis/Dissertation: If your license is for use in a thesis/dissertation your thesis may be submitted to your institution in either print or electronic form. Should your thesis be published commercially, please reapply for permission. These requirements include permission for the Library and Archives of Canada to supply single copies, on demand, of the complete thesis and include permission for UMI to supply single copies, on demand, of the complete thesis. Should your thesis be published commercially, please reapply for permission.  186  ELSEVIER LICENSE TERMS AND CONDITIONS Apr 11, 2011 This is a License Agreement between Andrea De Stefano ("You") and Elsevier ("Elsevier") provided by Copyright Clearance Center ("CCC"). The license consists of your order details, the terms and conditions provided by Elsevier, and the payment terms and conditions. All payments must be made in full to CCC. For payment instructions, please see information listed at the bottom of this form. Supplier Elsevier Limited The Boulevard,Langford Lane Kidlington,Oxford,OX5 1GB,UK Registered Company Number 1982084 Customer name Andrea De Stefano Customer address 905 4th Avenue New Westminster, BC V3M 1T1 License number 2645991195022 License date Apr 11, 2011 Licensed content publisher Elsevier Licensed content publication Lithos Licensed content title The trace element composition of silicate inclusions in diamonds: a review Licensed content author Thomas Stachel, Sonja Aulbach, Gerhard P. Brey, Jeff W. Harris, Ingrid Leost, Ralf Tappert, K.S.(Fanus) Viljoen Licensed content date September 2004 Licensed content volume Number 77 Licensed content issue number 1-4 Number of pages 19 Start Page 1 End Page 19 Type of Use reuse in a thesis/dissertation Intended publisher of new work other Portion figures/tables/illustrations Number of figures/tables/illustrations 1 Format both print and electronic Are you the author of this Elsevier article? No Will you be translating? No Order reference number Title of your thesis/dissertation Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds Expected completion date Apr 2011 Estimated size (number of pages) 178 Elsevier VAT number GB 494 6272 12 Permissions price 0.00 USD VAT/Local Sales Tax 0.0 USD / 0.0 GBP Total 0.00 USD  187  Terms and Conditions INTRODUCTION 1. The publisher for this copyrighted material is Elsevier. By clicking "accept" in connection with completing this licensing transaction, you agree that the following terms and conditions apply to this transaction (along with the Billing and Payment terms and conditions established by Copyright Clearance Center, Inc. ("CCC"), at the time that you opened your Rightslink account and that are available at any time at http://myaccount.copyright.com). GENERAL TERMS 2. Elsevier hereby grants you permission to reproduce the aforementioned material subject to the terms and conditions indicated. 3. Acknowledgement: If any part of the material to be used (for example, figures) has appeared in our publication with credit or acknowledgement to another source, permission must also be sought from that source. If such permission is not obtained then that material may not be included in your publication/copies. Suitable acknowledgement to the source must be made, either as a footnote or in a reference list at the end of your publication, as follows: “Reprinted from Publication title, Vol /edition number, Author(s), Title of article / title of chapter, Pages No., Copyright (Year), with permission from Elsevier [OR APPLICABLE SOCIETY COPYRIGHT OWNER].” Also Lancet special credit - “Reprinted from The Lancet, Vol. number, Author(s), Title of article, Pages No., Copyright (Year), with permission from Elsevier.” 4. Reproduction of this material is confined to the purpose and/or media for which permission is hereby given. 5. Altering/Modifying Material: Not Permitted. However figures and illustrations may be altered/adapted minimally to serve your work. Any other abbreviations, additions, deletions and/or any other alterations shall be made only with prior written authorization of Elsevier Ltd. (Please contact Elsevier at permissions@elsevier.com) 6. If the permission fee for the requested use of our material is waived in this instance, please be advised that your future requests for Elsevier materials may attract a fee. 7. Reservation of Rights: Publisher reserves all rights not specifically granted in the combination of (i) the license details provided by you and accepted in the course of this licensing transaction, (ii) these terms and conditions and (iii) CCC's Billing and Payment terms and conditions. 8. License Contingent Upon Payment: While you may exercise the rights licensed immediately upon issuance of the license at the end of the licensing process for the transaction, provided that you have disclosed complete and accurate details of your proposed use, no license is finally effective unless and until full payment is received from you (either by publisher or by CCC) as provided in CCC's Billing and Payment terms and conditions. If full payment is not received on a timely basis, then any license preliminarily granted shall be deemed automatically revoked and shall be void as if never granted. Further, in the event that you breach any of these terms and conditions or any of CCC's Billing and Payment terms and conditions, the license is automatically revoked and shall be void as if never granted. Use of materials as described in a revoked license, as well as any use of the materials beyond the scope of an unrevoked license, may constitute copyright infringement and publisher reserves the right to take any and all action to protect its copyright in the materials. 9. Warranties: Publisher makes no representations or warranties with respect to the licensed material.  188  10. Indemnity: You hereby indemnify and agree to hold harmless publisher and CCC, and their respective officers, directors, employees and agents, from and against any and all claims arising out of your use of the licensed material other than as specifically authorized pursuant to this license. 11. No Transfer of License: This license is personal to you and may not be sublicensed, assigned, or transferred by you to any other person without publisher's written permission. 12. No Amendment Except in Writing: This license may not be amended except in a writing signed by both parties (or, in the case of publisher, by CCC on publisher's behalf). 13. Objection to Contrary Terms: Publisher hereby objects to any terms contained in any purchase order, acknowledgment, check endorsement or other writing prepared by you, which terms are inconsistent with these terms and conditions or CCC's Billing and Payment terms and conditions. These terms and conditions, together with CCC's Billing and Payment terms and conditions (which are incorporated herein), comprise the entire agreement between you and publisher (and CCC) concerning this licensing transaction. In the event of any conflict between your obligations established by these terms and conditions and those established by CCC's Billing and Payment terms and conditions, these terms and conditions shall control. 14. Revocation: Elsevier or Copyright Clearance Center may deny the permissions described in this License at their sole discretion, for any reason or no reason, with a full refund payable to you. Notice of such denial will be made using the contact information provided by you. Failure to receive such notice will not alter or invalidate the denial. In no event will Elsevier or Copyright Clearance Center be responsible or liable for any costs, expenses or damage incurred by you as a result of a denial of your permission request, other than a refund of the amount(s) paid by you to Elsevier and/or Copyright Clearance Center for denied permissions. LIMITED LICENSE The following terms and conditions apply only to specific license types: 15. Translation: This permission is granted for non-exclusive world English rights only unless your license was granted for translation rights. If you licensed translation rights you may only translate this content into the languages you requested. A professional translator must perform all translations and reproduce the content word for word preserving the integrity of the article. If this license is to re-use 1 or 2 figures then permission is granted for non-exclusive world rights in all languages. 16. Website: The following terms and conditions apply to electronic reserve and author websites: Electronic reserve: If licensed material is to be posted to website, the web site is to be passwordprotected and made available only to bona fide students registered on a relevant course if: This license was made in connection with a course, This permission is granted for 1 year only. You may obtain a license for future website posting, All content posted to the web site must maintain the copyright information line on the bottom of each image, A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx or the Elsevier homepage for books at http://www.elsevier.com, and Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 17. Author website for journals with the following additional clauses: All content posted to the web site must maintain the copyright information line on the bottom of each image, and the permission granted is limited to the personal version of your paper. You are not  189  allowed to download and post the published electronic version of your article (whether PDF or HTML, proof or final version), nor may you scan the printed edition to create an electronic version, A hypertext must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx , As part of our normal production process, you will receive an e-mail notice when your article appears on Elsevier’s online service ScienceDirect (www.sciencedirect.com). That e-mail will include the article’s Digital Object Identifier (DOI). This number provides the electronic link to the published article and should be included in the posting of your personal version. We ask that you wait until you receive this e-mail and have the DOI to do any posting. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 18. Author website for books with the following additional clauses: Authors are permitted to place a brief summary of their work online only. A hyper-text must be included to the Elsevier homepage at http://www.elsevier.com All content posted to the web site must maintain the copyright information line on the bottom of each image. You are not allowed to download and post the published electronic version of your chapter, nor may you scan the printed edition to create an electronic version. Central Storage: This license does not include permission for a scanned version of the material to be stored in a central repository such as that provided by Heron/XanEdu. 19. Website (regular and for author): A hyper-text must be included to the Homepage of the journal from which you are licensing at http://www.sciencedirect.com/science/journal/xxxxx. or for books to the Elsevier homepage at http://www.elsevier.com 20. Thesis/Dissertation: If your license is for use in a thesis/dissertation your thesis may be submitted to your institution in either print or electronic form. Should your thesis be published commercially, please reapply for permission. These requirements include permission for the Library and Archives of Canada to supply single copies, on demand, of the complete thesis and include permission for UMI to supply single copies, on demand, of the complete thesis. Should your thesis be published commercially, please reapply for permission.  190  Confirmation Number: 10339903 Order Date: 04/11/2011 Customer Information Customer: Andrea De Stefano Account Number: 3000401497 Organization: Andrea De Stefano Email: sombra879@hotmail.com Phone: +1 (604) 780-8757 Payment Method: Invoice Order Details Economic geology and the bulletin of the Society of Economic Geologists Billing Status: Not Billed Order detail ID: 53459217 ISSN: 0361-0128 Publication year: 2008 Publication Type: Journal Publisher: ECONOMIC GEOLOGY PUBLISHING CO. Author/Editor: John W. F. Ketchum Your reference: Andrea De Stefano's thesis, chapter 1 Permission Status: Granted Permission type: Republish or display content Type of use: Dissertation Requested use: Dissertation Republication title: Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds Republishing organization: University of British Columbia Organization status: Non-profit 501(c)(3) Republication date: 04/25/2011 Circulation/ Distribution: 5 Type of content: Figure/ diagram/ table Description of requested content: Figure 10 Page range(s): 1179 Translating to: No Translation  191  192  SPRINGER LICENSE TERMS AND CONDITIONS Apr 11, 2011 This is a License Agreement between Andrea De Stefano ("You") and Springer ("Springer") provided by Copyright Clearance Center ("CCC"). The license consists of your order details, the terms and conditions provided by Springer, and the payment terms and conditions. All payments must be made in full to CCC. For payment instructions, please see information listed at the bottom of this form. License Number 2646031408734 License date Apr 11, 2011 Licensed content publisher Springer Licensed content publication Contributions to Mineralogy and Petrology Licensed content title Enigmatic diamonds in Archean calc-alkaline lamprophyres of Wawa, southern Ontario, Canada Licensed content author Andrea De Stefano Licensed content date Jan 1, 2006 Volume number 151 Issue number 2 Type of Use Thesis/Dissertation Portion Full text Number of copies 5 Author of this Springer article Yes and you are the sole author of the new work Order reference number Title of your thesis /dissertation Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds Expected completion date Apr 2011 Estimated size(pages) 178 Total 0.00 USD Terms and Conditions Introduction The publisher for this copyrighted material is Springer Science + Business Media. By clicking "accept" in connection with completing this licensing transaction, you agree that the following terms and conditions apply to this transaction (along with the Billing and Payment terms and conditions established by Copyright Clearance Center, Inc. ("CCC"), at the time that you opened your Rightslink account and that are available at any time at http://myaccount.copyright.com). Limited License With reference to your request to reprint in your thesis material on which Springer Science and Business Media control the copyright, permission is granted, free of charge, for the use indicated in your enquiry. Licenses are for one-time use only with a maximum distribution equal to the number that you identified in the licensing process. This License includes use in an electronic form, provided it is password protected or on the university's intranet, destined to microfilming by UMI and University 193  repository. For any other electronic use, please contact Springer at (permissions.dordrecht@springer.com or permissions.heidelberg@springer.com). The material can only be used for the purpose of defending your thesis, and with a maximum of 100 extra copies in paper. Although Springer holds copyright to the material and is entitled to negotiate on rights, this license is only valid, provided permission is also obtained from the (co) author (address is given with the article/chapter) and provided it concerns origin all material which does not carry references to other sources (if material in question appears with credit to another source, authorization from that source is required as well). Permission free of charge on this occasion does not prejudice any rights we might have to charge for reproduction of our copyrighted material in the future. Altering/Modifying Material: Not Permitted However figures and illustrations may be altered minimally to serve your work. Any other abbreviations, additions, deletions and/or any other alterations shall be made only with prior written authorization of the author(s) and/or Springer Science + Business Media. (Please contact Springer at permissions.dordrecht@springer.com or permissions.heidelberg@springer.com) Reservation of Rights Springer Science + Business Media reserves all rights not specifically granted in the combination of (i) the license details provided by you and accepted in the course of this licensing transaction, (ii) these terms and conditions and (iii) CCC's Billing and Payment terms and conditions. Copyright Notice: Please include the following copyright citation referencing the publication in which the material was originally published. Where wording is within brackets, please include verbatim. "With kind permission from Springer Science+Business Media: <book/journal title, chapter/article title, volume, year of publication, page, name(s) of author(s), figure number(s), and any original (first) copyright notice displayed with material>." Warranties: Springer Science + Business Media makes no representations or warranties with respect to the licensed material. Indemnity You hereby indemnify and agree to hold harmless Springer Science + Business Media and CCC, and their respective officers, directors, employees and agents, from and against any and all claims arising out of your use of the licensed material other than as specifically authorized pursuant to this license. No Transfer of License This license is personal to you and may not be sublicensed, assigned, or transferred by you to any other person without Springer Science + Business Media's written permission. No Amendment Except in Writing This license may not be amended except in a writing signed by both parties (or, in the case of Springer Science + Business Media, by CCC on Springer Science + Business Media's behalf). Objection to Contrary Terms  194  Springer Science + Business Media hereby objects to any terms contained in any purchase order, acknowledgment, check endorsement or other writing prepared by you, which terms are inconsistent with these terms and conditions or CCC's Billing and Payment terms and conditions. These terms and conditions, together with CCC's Billing and Payment terms and conditions (which are incorporated herein), comprise the entire agreement between you and Springer Science + Business Media (and CCC) concerning this licensing transaction. In the event of any conflict between your obligations established by these terms and conditions and those established by CCC's Billing and Payment terms and conditions, these terms and conditions shall control. Jurisdiction All disputes that may arise in connection with this present License, or the breach thereof, shall be settled exclusively by the country's law in which the work was originally published.  195  SPRINGER LICENSE TERMS AND CONDITIONS Apr 11, 2011 This is a License Agreement between Andrea De Stefano ("You") and Springer ("Springer") provided by Copyright Clearance Center ("CCC"). The license consists of your order details, the terms and conditions provided by Springer, and the payment terms and conditions. All payments must be made in full to CCC. For payment instructions, please see information listed at the bottom of this form. License Number 2646031503750 License date Apr 11, 2011 Licensed content publisher Springer Licensed content publication Contributions to Mineralogy and Petrology Licensed content title Diamonds and eclogites of the Jericho kimberlite (Northern Canada) Licensed content author Andrea De Stefano Licensed content date Jan 1, 2009 Volume number 158 Issue number 3 Type of Use Thesis/Dissertation Portion Full text Number of copies 5 Author of this Springer article Yes and you are the sole author of the new work Order reference number Title of your thesis / dissertation Diamonds in cratonic and orogenic settings: a study of Jericho and Wawa diamonds Expected completion date Apr 2011 Estimated size(pages) 178 Total 0.00 USD Terms and Conditions Introduction The publisher for this copyrighted material is Springer Science + Business Media. By clicking "accept" in connection with completing this licensing transaction, you agree that the following terms and conditions apply to this transaction (along with the Billing and Payment terms and conditions established by Copyright Clearance Center, Inc. ("CCC"), at the time that you opened your Rightslink account and that are available at any time at http://myaccount.copyright.com). Limited License With reference to your request to reprint in your thesis material on which Springer Science and Business Media control the copyright, permission is granted, free of charge, for the use indicated in your enquiry. Licenses are for one-time use only with a maximum distribution equal to the number that you identified in the licensing process. This License includes use in an electronic form, provided it is password protected or on the university's intranet, destined to microfilming by UMI and University  196  repository. For any other electronic use, please contact Springer at (permissions.dordrecht@springer.com or permissions.heidelberg@springer.com). The material can only be used for the purpose of defending your thesis, and with a maximum of 100 extra copies in paper. Although Springer holds copyright to the material and is entitled to negotiate on rights, this license is only valid, provided permission is also obtained from the (co) author (address is given with the article/chapter) and provided it concerns origin all material which does not carry references to other sources (if material in question appears with credit to another source, authorization from that source is required as well). Permission free of charge on this occasion does not prejudice any rights we might have to charge for reproduction of our copyrighted material in the future. Altering/Modifying Material: Not Permitted However figures and illustrations may be altered minimally to serve your work. Any other abbreviations, additions, deletions and/or any other alterations shall be made only with prior written authorization of the author(s) and/or Springer Science + Business Media. (Please contact Springer at permissions.dordrecht@springer.com or permissions.heidelberg@springer.com) Reservation of Rights Springer Science + Business Media reserves all rights not specifically granted in the combination of (i) the license details provided by you and accepted in the course of this licensing transaction, (ii) these terms and conditions and (iii) CCC's Billing and Payment terms and conditions. Copyright Notice: Please include the following copyright citation referencing the publication in which the material was originally published. Where wording is within brackets, please include verbatim. "With kind permission from Springer Science+Business Media: <book/journal title, chapter/article title, volume, year of publication, page, name(s) of author(s), figure number(s), and any original (first) copyright notice displayed with material>." Warranties: Springer Science + Business Media makes no representations or warranties with respect to the licensed material. Indemnity You hereby indemnify and agree to hold harmless Springer Science + Business Media and CCC, and their respective officers, directors, employees and agents, from and against any and all claims arising out of your use of the licensed material other than as specifically authorized pursuant to this license. No Transfer of License This license is personal to you and may not be sublicensed, assigned, or transferred by you to any other person without Springer Science + Business Media's written permission. No Amendment Except in Writing This license may not be amended except in a writing signed by both parties (or, in the case of Springer Science + Business Media, by CCC on Springer Science + Business Media's behalf). Objection to Contrary Terms  197  Springer Science + Business Media hereby objects to any terms contained in any purchase order, acknowledgment, check endorsement or other writing prepared by you, which terms are inconsistent with these terms and conditions or CCC's Billing and Payment terms and conditions. These terms and conditions, together with CCC's Billing and Payment terms and conditions (which are incorporated herein), comprise the entire agreement between you and Springer Science + Business Media (and CCC) concerning this licensing transaction. In the event of any conflict between your obligations established by these terms and conditions and those established by CCC's Billing and Payment terms and conditions, these terms and conditions shall control. Jurisdiction All disputes that may arise in connection with this present License, or the breach thereof, shall be settled exclusively by the country's law in which the work was originally published.  198  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.24.1-0053094/manifest

Comment

Related Items