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Mineral inclusions in diamonds from Karowe Mine, Botswana: super-deep sources for super-sized diamonds?

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Abstract

Mineral inclusions in diamonds play a critical role in constraining the relationship between diamonds and mantle lithologies. Here we report the first major and trace element study of mineral inclusions in diamonds from the Karowe Mine in north-east Botswana, along the western edge of the Zimbabwe Craton. From a total of 107 diamonds, 134 silicate, 15 oxide, and 22 sulphide inclusions were recovered. The results reveal that 53% of Karowe inclusion-bearing diamonds derived from eclogitic sources, 44% are peridotitic, 2% have a sublithospheric origin, and 1% are websteritic. The dominant eclogitic diamond substrates sampled at Karowe are compositionally heterogeneous, as reflected in wide ranges in the CaO contents (4–16 wt%) of garnets and the Mg# (69–92) and jadeite contents (14–48 mol%) of clinopyroxenes. Calculated bulk rock REEN patterns indicate that both shallow and deep levels of the subducted slab(s) were sampled, including cumulate-like protoliths. Peridotitic garnet compositions largely derive from harzburgite/dunite substrates (~90%), with almost half the garnets having CaO contents <1.8 wt%, consistent with pyroxene-free (dunitic) sources. The highly depleted character of the peridotitic diamond substrates is further documented by the high mean and median Mg# (93.1) of olivine inclusions. One low-Ca garnet records a very high Cr2O3 content (14.7 wt%), implying that highly depleted cratonic lithosphere at the time of diamond formation extended to at least 220 km depth. Inclusion geothermobarometry indicates that the formation of peridotitic diamonds occurred along a 39–40 mW/m2 model geotherm. A sublithospheric inclusion suite is established by three eclogitic garnets containing a majorite component, a feature so far unique within the Orapa cluster. These low- and high-Ca majoritic garnets follow pyroxenitic and eclogitic trends of majoritic substitution, respectively. The origin of the majorite-bearing diamonds is estimated to be between 330 to 420 km depth, straddling the asthenosphere–transition zone boundary. This new observation of superdeep mineral inclusions in Karowe diamonds is consistent with a sublithospheric origin for the exceptionally large diamonds from this mine.

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References

  • Armstrong JT (1995) CITZAF-a package of correction programs for the quantitative electron microbeam X-ray of thick polished materials, thin-films, and particles. Microbeam Anal 4:177–200

    Google Scholar 

  • Aulbach S, Jacob DE (2016) Major-and trace-elements in cratonic eclogites and pyroxenites reveal heterogeneous sources and metamorphic processing of low-pressure protholiths. Lithos 262:586–605

    Article  Google Scholar 

  • Aulbach S, Viljoen KS (2015) Eclogite xenoliths from the Lace kimberlite, Kaapvaal Craton:From convecting mantle source to palaeo-ocean floor and back. Earth Planet Sc Lett 431:274–286

    Article  Google Scholar 

  • Aulbach S, Jacob DE, Cartigny P, Stern RA, Simonetti SS, Wörner G, Viljoen KS (2017) Eclogite xenoliths from Orapa: Ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin. Geochim Cosmochim Acta 213:574–592

    Article  Google Scholar 

  • Beard BL, Fraracci KN, Clayton RA, Mayeda TK, Snyder GA, Sobolev NV, Taylor LA (1996) Petrography and geochemistry of eclogites from the Mir kimberlite, Yakutia, Russia. Contrib Mineral Petrol 125:293–310

    Article  Google Scholar 

  • Bell AS, Burger PV, Le L, Shearer CK, Papike JJ, Sutton SR, Newville M, Jones J (2014) XANES measurements of Cr valence in olivine and their applications to planetary basalts. Am Mineral 99(7):1404–1412

    Article  Google Scholar 

  • Bernstein S, Kelemen PB, Hanghøj K (2007) Consistent olivine Mg# in cratonic mantle reflects Archean mantle melting to the exhaustion of orthopyroxene. Geology 35(5):459–462

    Article  Google Scholar 

  • Beyer C, Frost DJ (2017) The depth of sub-lithospheric diamond formation and the redistribution of carbon in the deep mantle. Earth Planet Sc Lett 461:30–39

    Article  Google Scholar 

  • Brey GP, Köhler T (1990) Geothermobarometry in four-phase lherzolites II. New thermobarometers, and practical assessment of existing thermobarometers. J Petrol 31(6):1353–1378

    Article  Google Scholar 

  • Brey GP, Bulatov V, Girnis A, Harris JW, Stachel T (2004) Ferropericlase-a lower mantle phase in the upper mantle. Lithos 77:655–663

    Article  Google Scholar 

  • Bulanova GP, Griffin WL, Ryan CG, Shestakova OY, Barnes SJ (1996) Trace elements in sulfide inclusions from Yakutian diamonds. Contrib Mineral Petrol 124:111–125

    Article  Google Scholar 

  • Canil D, O'Neill HSC (1996) Distribution of ferric iron in some upper-mantle assemblages. J Petrol 37(3):609–635

    Article  Google Scholar 

  • Carlson RW, Pearson DG, Boyd FR, Shirey SB, Irvine G, Menzies AH, Gurney JJ (1999) Re–Os systematics of lithospheric peridotites: implications for lithosphere formation and preservation. Proceedings 7th International Kimberlite Conference, Red Roof Design, Cape Town, pp 99-108

  • D’Haenens-Johansson UFS, Smith EM, Smit KV, Wang W, Moses TM (2017) The 812-carat pure Type IaB constellation diamond from Karowe- Part of an even larger rough? Extended Abstracts, 11th International Kimberlite Conference, Gaborone, Botswana, 11IKC-4611

  • De Wit MJ, de Ronde CE, Tredoux M, Roering C, Hart RJ, Armstrong RA, Green RW, Peberdy E, Hart RA (1992) Formation of an Archaean continent. Nature 357(6379):553–562

    Article  Google Scholar 

  • Deines P, 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

    Article  Google Scholar 

  • Deines P, Harris JW, Gurney JJ (1993) Depth-related carbon isotope and nitrogen concentration variability in the mantle below the Orapa kimberlite, Botswana, Africa. Geochim Cosmochim Acta 57(12):2781–2796

    Article  Google Scholar 

  • Deines P, Stachel T, Harris JW (2009) Systematic regional variations in diamond carbon isotopic composition and inclusion chemistry beneath the Orapa kimberlite cluster, in Botswana. Lithos 112:776–784

    Article  Google Scholar 

  • Floyd P (1991) Oceanic basalts. Springer, New York, 456 pp

    Google Scholar 

  • Foley S, Tiepolo M, Vannucci R (2002) Growth of early continental crust controlled by melting of amphibolite in subduction zones. Nature 417(6891):837–840

    Article  Google Scholar 

  • Fouch MJ, James DE, VanDecar JC, van der Lee S, Kaapvaal SG (2004) Mantle seismic structure beneath the Kaapvaal and Zimbabwe Cratons. South African J Geol 107(1–2):33–44

    Article  Google Scholar 

  • Griffin WL, O'Reilly SY, Natapov LM, Ryan CG (2003) The evolution of lithospheric mantle beneath the Kalahari Craton and its margins. Lithos 71:215–241

    Article  Google Scholar 

  • Grütter HS (2009) Pyroxene xenocryst geotherms: Techniques and application. Lithos 112(Supplement 2):1167–1178

    Article  Google Scholar 

  • Grütter HS, Apter DB, Kong J (1999) Crust–mantle coupling: evidence from mantle-derived xenocrystic garnets. In Gurney JJ, Gurney JL, Pasco MD, Richardson SH (Eds), The J.B Dawson Volume, Proceedings of the VIth International Kimberlite Conference, Red Roof Design, Cape Town, pp 307-313

  • Grütter HS, Gurney JJ, Menzies AH, Winter F (2004) An updated classification scheme for mantle-derived garnet, for use by diamond explorers. Lithos 77:841–857

    Article  Google Scholar 

  • Grütter H, Latti D, Menzies A (2006) Cr-saturation arrays in concentrate garnet compositions from kimberlite and their use in mantle barometry. J Petrol 47:801–820

    Article  Google Scholar 

  • Gurney JJ, Harris JW, Rickard RS (1984) Silicate and oxide inclusions in diamonds from the Orapa Mine, Botswana. In: Kornprobst J (ed) Kimberlites II: the mantle and crust-mantle relationships. Developments in Petrology, vol 11. Elsevier, Amsterdam, pp 3–9

  • Harley SL (1984) An experimental study of the partitioning of Fe and Mg between garnet and orthopyroxene. Contrib Mineral Petrol 86:359–373

    Article  Google Scholar 

  • Harte B (2010) Diamond formation in the deep mantle: the record of mineral inclusions and their distribution in relation to mantle dehydration zones. Mineral Mag 74(2):189–215

    Article  Google Scholar 

  • Hasterok D, Chapman DS (2011) Heat production and geotherms for the continental lithosphere. Earth Planet Sc Lett 307:59–70

    Article  Google Scholar 

  • Horstwood MS, Nesbitt RW, Noble SR, Wilson JF (1999) U-Pb zircon evidence for an extensive early Archean craton in Zimbabwe: A reassessment of the timing of craton formation, stabilization, and growth. Geology 27(8):707–710

    Article  Google Scholar 

  • Hunt L, Stachel T, McCandless TE, Armstrong J, Muehlenbachs K (2012) Diamonds and their mineral inclusions from the Renard kimberlites in Quebec. Lithos 142:267–284

    Article  Google Scholar 

  • Ireland TR, Rudnick RL, Spetsius Z (1994) Trace elements in diamond inclusions from eclogites reveal link to Archean granites. Earth Planet Sc Lett 128:199–213

    Article  Google Scholar 

  • Jacob DE (2004) Nature and origin of eclogite xenoliths from kimberlites. Lithos 77:295–316

    Article  Google Scholar 

  • Key RM, Ayres N (2000) The 1998 edition of the national geological map of Botswana. J Afr Earth Sci 30(3):427–451

    Article  Google Scholar 

  • Kiseeva ES, Yaxley GM, Stepanov AS, Tkalčić H, Litasov KD, Kamenetsky VS (2013) Metapyroxenite in the mantle transition zone revealed from majorite inclusions in diamonds. Geology 41:883–886

    Article  Google Scholar 

  • Kiseeva ES, Wood BJ, Ghosh S, Stachel T (2016) The pyroxenite-diamond connection. Geochem Perspect Lett 2:1–9

    Article  Google Scholar 

  • Kopylova MG, Gurney JJ, Daniels LR (1997) Mineral inclusions in diamonds from the River Ranch kimberlite, Zimbabwe. Contrib Mineral Petrol 129:366–366

    Article  Google Scholar 

  • Krogh EJ (1988) The garnet-clinopyroxene Fe-Mg geothermometer-a reinterpretation of existing experimental data. Contrib Mineral Petrol 99:44–48

    Article  Google Scholar 

  • Li JP, O'Neill HSC, Seifert F (1995) Subsolidus phase relations in the system MgO-SiO2-Gr-O in equilibrium with metallic Cr, and their significance for the petrochemistry of Chromium. J Petrol 36(1):107–132

    Article  Google Scholar 

  • Majaule T, Hanson RE, Key RM, Singletary SJ, Martin MW, Bowring SA (2001) The Magondi Belt in northeast Botswana: regional relations and new geochronological data from the Sua Pan area. J Afr Earth Sci 32(2):257–267

    Article  Google Scholar 

  • McDonough WF, Sun S (1995) The composition of the Earth. Chem Geol 120(3–4):223–253

    Article  Google Scholar 

  • McGuire AV, Francis CA, Dyar MD (1992) Mineral standards for electron microprobe analyses of oxygen. Am Mineral 77:1087–1091

    Google Scholar 

  • Meyer H (1987) Inclusions in diamond. In: Nixon PH (ed) Mantle xenoliths. Wiley, Chichester, pp 501–522

    Google Scholar 

  • Moore AE (2014) The origin of large irregular gem-quality type II diamonds and the rarity of blue type IIb varieties. South African J Geol 117:219–236

    Article  Google Scholar 

  • Moore RO, Gurney JJ, Griffin WL, Shimizu N (1991) Ultra-high pressure garnet inclusions in Monastery diamonds: trace element abundance patterns and conditions of origin. Eur J Mineral 3:213–230

    Article  Google Scholar 

  • Morimoto N (1988) Nomenclature of pyroxenes. Schweiz Mineral Petrogr Mitt 68:95–111

    Google Scholar 

  • O'Neill HSC, Wood BJ (1979) An experimental study of Fe-Mg partitioning between garnet and olivine and its calibration as a geothermometer. Contrib Mineral Petrol 70:59–70

    Article  Google Scholar 

  • Paton C, Hellstrom J, Paul B, Woodhead J, Hergt J (2011) Iolite: Freeware for the visualisation and processing of mass spectrometric data. J Anal At Spectrom 26:2508–2518

    Article  Google Scholar 

  • Rollinson HR, Whitehouse M (2011) The growth of the Zimbabwe Craton during the late Archaean: An ion microprobe U-Pb zircon study. J Geol Soc 168(4):941–952

    Article  Google Scholar 

  • Schulze DJ (2003) A classification scheme for mantle-derived garnets in kimberlite: a tool for investigating the mantle and exploring for diamonds. Lithos 71:195–213

    Article  Google Scholar 

  • Shee SR, Gurney JJ (1979) The Mineralogy of xenoliths from Orapa, Botswana. In: Boyd FR, Meyer HOA (eds) The mantle sample: inclusions in kimberlites and related rocks. Proceedings of the Second International Kimberlite Conference, Am Geophys Union, vol 2, pp 237–249

  • Shu Q, Brey GP, Hoefer HE, Zhao Z, Pearson DG (2016) Kyanite/corundum eclogites from the Kaapvaal Craton: subducted troctolites and layered gabbros from the Mid-to Early Archean. Contrib Mineral Petrol 171:11–34

    Article  Google Scholar 

  • Smart KA, Heaman LM, Chacko T, Simonetti A, Kopylova M, Mah D, Daniels D (2009) The origin of high-MgO diamond eclogites from the Jericho Kimberlite, Canada. Earth Planet Sc Lett 284(3–4):527–537

    Article  Google Scholar 

  • Smith CB, Pearson DG, Bulanova GP, Beard AD, Carlson RW, Wittig N, Sims K, Chimuka L, Muchemwa E (2009) Extremely depleted lithospheric mantle and diamonds beneath the southern Zimbabwe Craton. Lithos 112:1120–1132

    Article  Google Scholar 

  • Smith EM, Shirey SB, Nestola F, Bullock ES, Wang J, Richardson SH, Wang W (2016) Large gem diamonds from metallic liquid in Earth’s deep mantle. Science 354:1403–1405

    Article  Google Scholar 

  • Sobolev NV Jr, Kuznetsova IK, Zyuzin NI (1968) The petrology of grospydite xenoliths from the Zagadochnaya kimberlite pipe in Yakutia. J Petrol 9:253–280

    Article  Google Scholar 

  • Spetsius ZV (2004) Petrology of highly aluminous xenoliths from kimberlites of Yakutia. Lithos 77:525–538

    Article  Google Scholar 

  • Stachel T, Harris JW (2008) The origin of cratonic diamonds-constraints from mineral inclusions. Ore Geol Rev 34:5–32

    Article  Google Scholar 

  • Stachel T, Luth RW (2015) Diamond formation-Where, when and how? Lithos 220-223:200–220

    Article  Google Scholar 

  • Stachel T, Aulbach S, Brey GP, Harris JW, Leost I, Tappert R, Viljoen KF (2004a) The trace element composition of silicate inclusions in diamonds: a review. Lithos 77:1–19

    Article  Google Scholar 

  • Stachel T, Viljoen KS, McDade P, Harris JW (2004b) Diamondiferous lithospheric roots along the western margin of the Kalahari Craton-the peridotitic inclusion suite in diamonds from Orapa and Jwaneng. Contrib Mineral Petrol 147:32–47

    Article  Google Scholar 

  • Stachel T, Harris JW, Hunt L, Muehlenbachs K, Kobussen A, EIMF (2015) Argyle diamonds- How subduction along the Kimberley Craton edge generated the world's biggest's diamond deposit. Soc Econ Geol Spec P 20

  • Stagno V, Ojwang DO, McCammon CA, Frost DJ (2013) The oxidation state of the mantle and the extraction of carbon from Earth’s interior. Nature 493:84–88

    Article  Google Scholar 

  • Stiefenhofer J, Viljoen KS, Marsh JS (1997) Petrology and geochemistry of peridotite xenoliths from the Letlhakane kimberlites, Botswana. Contrib Mineral Petrol 127(1–2):147–158

    Article  Google Scholar 

  • Tappert R, Stachel T, Harris JW, Muehlenbachs K, Ludwig T, Brey GP (2005) Subducting oceanic crust: the source of deep diamonds. Geology 33:565–568

    Article  Google Scholar 

  • Treloar PJ (1988) The geological evolution of the Magondi mobile belt, Zimbabwe. Precambrian Res 38(1):55–73

    Article  Google Scholar 

  • Van Reenen DD, Barton JM, Roering C, Smith CA, Van Schalkwyk JF (1987) Deep crystal response to continental collision: The Limpopo belt of southern Africa. Geology 15(1):11–14

    Article  Google Scholar 

  • Viljoen F, Dobbe R, Harris J, Smit B (2010) Trace element chemistry of mineral inclusions in eclogitic diamonds from the Premier (Cullinan) and Finsch kimberlites, South Africa: implications for the evolution of their mantle source. Lithos 118:156–168

    Article  Google Scholar 

  • Walter MJ, Bulanova GP, Armstrong LS, Keshav S, Blundy JD, Gudfinnsson G, Lord OT, Lennie AR, Clark SM, Smith CB (2008) Primary carbonatite melt from deeply subducted oceanic crust. Nature 454(7204):622–630

    Article  Google Scholar 

  • Wyllie PJ, Huang W (1976) Carbonation and melting reactions in the system CaO-MgO-SiO2-CO2 at mantle pressures with geophysical and petrological applications. Contrib Mineral Petr 54:79–107

    Article  Google Scholar 

  • Yurimoto H, Ohtani E (1992) Element partitioning between majorite and liquid: a secondary ion mass spectrometric study. Geophys Res Lett 19(1):17–20

    Article  Google Scholar 

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Acknowledgments

Lucara Diamond Corporation is sincerely thanked for the provision of production diamonds for this study and JWH also extents gratitude to the Company for the hospitality and resources provided, which enabled the diamonds to be collected. John Gurney (Cape Town) is thanked for bringing the project to the Lucara board and getting us started. Andrew J. Locock is thanked for his assistance and advice related to microprobe analyses. T.M. thanks Janina Czas and Nicole Meyer (University of Alberta) for comments, discussions and advice that helped to improve this manuscript. Thoughtful reviews by Sonja Aulbach (Frankfurt) and Ben Harte (Edinburgh) are gratefully acknowledged. T.M. received a bursary from the Government of Botswana as part of Pre-University Academic Programmes under Botswana International University of Science and Technology (BIUST). T.S. acknowledges research funding through an Natural Sciences and Engineering Research Council (NSERC) Discovery Grant and the Canada Research Chairs program.

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Authors and Affiliations

  1. Department of Earth and Atmospheric Sciences 1-26 Earth Sciences Building, Edmonton, T6H 2E3, Canada

    Theetso Motsamai, Thomas Stachel & D. Graham Pearson

  2. School of Geographical and Earth Sciences, Gregory Building, Glasgow, G12 8QQ, UK

    Jeffrey W. Harris

  3. Lucara Diamond Corporation, Suite 2000, 885 West Georgia Street, Vancouver, V6C 3E8, Canada

    John Armstrong

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  1. Theetso Motsamai
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  2. Jeffrey W. Harris
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Correspondence to Theetso Motsamai.

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Motsamai, T., Harris, J.W., Stachel, T. et al. Mineral inclusions in diamonds from Karowe Mine, Botswana: super-deep sources for super-sized diamonds?. Miner Petrol 112 (Suppl 1), 169–180 (2018). https://doi.org/10.1007/s00710-018-0604-9

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