Abstract
Rb-Sr isotopic dating of phlogopite megacryst samples separated from Sturgeon Lake kimberlite, Saskatchewan, yields a crystallization age of 98±1 Ma (2 σ, MSWD=1.2; 87Sr/86Sr(t)=0.7059). The 40Ar/39Ar analyses of a phlogopite megacryst sample indicate the presence of large amounts of excess 40Ar and yield an excessively old age of ∼410 Ma. Assessment of the Ar data using isotope correlation plots indicates clustering of the data points about a mixing line between the radiogenic 40Ar component at 98 Ma and a trapped component with uniform 36Ar/40Ar and Cl/40Ar. Values of {ie212-1} as high as +20%. (VSMOW) for calcite from the groundmass and a whole-rock sample indicate pervasive lowtemperature alteration. The {ie212-2} of matrix carbonate is-11.3%. (PDB), slightly lighter than typical values from the literature. The {ie212-3} values of about +5%. (VSMOW) for brown phlogopite megacrysts may be primary, green phlogopites are interpreted to be an alteration product of the brown variety and are 2%. heavier. Initial Nd-Sr-Pb isotopic ratios for a whole-rock sample {ie212-4}; 87Sr/86Sr=0.7063, 206Pb/204Pb=18.67, 207Pb/204Pb=15.54, 208Pb/204Pb=38.97) suggest an affinity with group I kimberlites. Initial {ie212-5} values of +1.7 and +0.5 (87Sr/ 86Sr(t)=0.7053 and 0.7050) for eclogitic and lherzolitic garnet megacryst samples, and values of 0.0 for two phlogopite megacryst samples reflect an origin from an isotopically evolving melt due to assimilation of heterogeneous mantle. Lilac high-Cr lherzolitic garnet megacrysts give an unusually high {ie212-6} of +28.6 (87Sr/86Sr=0.7046) indicating a xenocrystic origin probably from the lithospheric mantle. The very radiogenic 87Sr/86Sr and 206Pb/204Pb ratios of the kimberlite are consistent with melting of EM II (enriched) mantle components.
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References
Alibert C, Albarède F (1988) Relationships between mineralogical, chemical, and isotopic properties of some North American kimberlites. J Geophys Res 93:7643–7671
Allsopp HL, Roddick JC (1984) Rb-Sr and 40Ar-39Ar are determinations on phlogopite micas from the Pre-Lebombo group Dokolayo kimberlite pipe. Geol Soc S Afr Spec Publ 13:27–271
Boyd FR (1987) High- and low-temperature garnet peridotite xenoliths and their possible relationships to the lithosphere-asthenosphere boundary beneath southern Africa. In: Nixon PH (ed) Mantle xenoliths. John Wiley and Sons Ltd, Chichester, pp 403–412
Brooks C, Hart SR, Wendt I (1972) Realistic use of two-error regression treatments as applied to rubidium-strontium data. Rev Geophys Space Phys 10:551–577
Brown RW, Allsopp HL, Bristow JW, Smith CB (1989) Improved precision of Rb-Sr dating of kimberlitic micas: an assessment of a leaching technique. Chem Geol 79:125–136
Chiba H, Chacko T, Clayton RN, Goldsmith JR (1989) Oxygen isotope fractionations involving diopside, forsterite, magnetite, and calcite: applicatin to geothermometry. Geochim Cosmochim Acta 53:2985–2995
Claesson S, Roddick JC (1983) 40Ar/39Ar data on the age and metamorphism of the Ottfjallet dolerites, Srav Nappe, Swedish Caledonides. Lithos 16:1–73
Clauer N O'Neil JR, Bonnot-Courtois C (1982) The effect of natural weathering on the chemical and isotopic compositions of biotites. Geochim Cosmochim Acta 46:1755–1762
Clayton RN, Mayeda TK (1963) The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotope analysis. Geochim Cosmochim Acta 27:43–52
Clement CR, Skinner EMW (1985) A textural-genetic classification of kimberlite. Trans Geol Soc S Afr 88:403–409
Cole DR (1985) A preliminary evaluation of oxygen isotopic exchange between chlorite and water (abstract). Geol Soc Am Abstr Program 17:550
Dawson JB, Stephens WE (1975) Statistical classification of garnets from kimberlites and associated xenoliths. J Geol 83:589–607
Deines P, Gold DP (1973) The isotopic composition of carbonatite and kimberlite carbonates and their bearing on the isotopic composition of deep-seated carbon. Geochim Cosmochim Acta 37:1709–1733
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 57:2781–2796
Foland KA (1983) 40Ar/39Ar incremental heating plateaus for biotites with excess argon. Isot Geosc 1:3–21
Fortier SM, Lüttge A, Satir M, Metz P (1994) Oxygen isotope fractionation between fluorphlogopite and calcite: an experimental determination of temperature dependence and F-/OH- effects. Eur J Mineral 6:53–65
Haggerty SE (1994) Superkimberlites: a geodynamic diamond window to the Earth's core. Earth Planet Sci Lett 122:57–69
Harper C (1989) Kimberlites in the western Canadian sedimentary basins. In: Drury MJ (ed) Can Cont Drilling Program Rep 89-3, pp 25–27
Heaman LM (1989) The nature of the sub-continental mantle from Sr-Nd-Pb isotopic studies on kimberlitic perovskite. Earth Planet Sci Lett 92:323–334
Hess JC, Lippolt HJ, Wirth R (1987) Interpretation of 40Ar/39Ar spectra of biotites: evidence from hydrothermal degassing experiments and TEM studies. Chem Geol Isot Geosci 66:137–149
Hofmann AW, Jochum KP, Seufer M, White WM (1989) Nb and Pb in oceanic basalts: new constraints on mantle evolution. Earth Planet Sci Lett 79:33–45
Jaques AL, Lewis JD, Smith CB, Gregory GP, Ferguson J, Chappell BW, McCulloch MT (1984) The diamond-bearing ultrapotassic (lamproitic) rocks of the West Kimberley region, Western Australia. In: Kornprobst J (ed) Kimberlites and related rocks, vol 1. Elsevier, New York, pp 225–254
Jochum KP, McDonough WF, Palme H, Spettel B (1989) Compositional constraints on the continental lithospheric mantle from trace elements in spinel peridotite xenoliths. Nature 340:548–550
Kaneoka I, Aoki K-I (1978) 40AR/39Ar analysis of phlogopite nodules and phlogopite-bearing peridotites in South African kimberlites. Earth Planet Sci Lett 40:119–129
Kramers JD (1977) Lead and strontium isotopes in Cretaceous kimberlites and mantle-derived xenoliths from southern Africa. Earth Planet Sci Lett 34:419–431
Lanphere MA, Dalrymple GB (1976) Identification of excess 40Ar by the 40Ar/39Ar age spectrum technique. Earth Planet Sci Lett 32:141–148
Letendre CR (1992) Sturgeon Lake area NTS 73G8, central Saskatchewan mineral deposition S-124439, field work and drilling results. Monopros Ltd. Internal Rep
Ludwig KR (1988) ISOPLOT for MS-DOS, a plotting and regression program for radiogenic-isotope data, for IBM-PC compatible computers. US Geol Surv Open-File Rep 88-557
Mattey DP, Carr RH, Wright IP, Pillinger CT (1984) Carbon isotopes in submarine basalts. Earth Planet Sci Lett 70:196–206
McCrea JM (1950) On the isotopic chemistry of carbonates and a paleotemperature scale. J Chem Phys 18:849–857
McDonough WF, McCulloch MT (1987) The southeast Australian lithospheric mantle: isotopic and geochemical constraints on its growth and evolution. Earth Planet Sci Lett 86:327–340
Meyer HOA (1987) Inclusions in diamonds. In: (ed) PH Nixon Mantle xenoliths. John Wiley and Sons Ltd, Chichester 501–523
Mitchell RH (1986) Kimberlites: mineralogy, geochemistry and petrology, Plenum, New York
Nixon PH, Boyd FR (1979) Garnet-bearing lherzolites and discrete nodule suites from the Mlaita alnoite, Solomon Islands, S.W. Pacific, and their bearing on oceanic composition and geotherm. In: Boyd FR, Meyer HOA (eds) The mantle sample: inclusions in kimberlites and other volcanics, vol 2. Proc 2nd Kimb Conf, Am Geophys Union, Washington, DC, pp 400–423
Pankhurst RJ, Moorbath S, Rex DC, Turner G (1973) Mineral age patterns in ca. 3700 million year old rocks from West Greenland. Earth Planet Lett 20:157–170
Philips D, Onstott TC (1986) Application of 36Ar/40Ar versus 39Ar/40Ar correlation diagrams to the 40Ar/39Ar spectra of phlogopites from southern African kimberlites. Geophys Res Lett 13:89–692
Philips D, Onstott TC (1988) Argon isotopic zoning in mantle phlogopite. Geology 16:542–546
Pineau F, Javoy M (1983) Carbon isotopes and concentration in mid-ocean ridge basalts. Earth Planet Sci Lett 62:239–257
Richardson SH, Erlank AJ, Harris JW, Hart SR (1990) Eclogitic diamonds of Proterozoic age from Cretaceous kimberlites. Nature 346:54–56
Richardson SH, Harris JW, Gurney JJ (1993) Three generations of diamonds from old continental mantle. Nature 366:256–258
Ringwood AE, Kesson SE, Hibberson W, Ware N (1992) Origin of kimberlites and related magmas. Earth Planet Sci Lett 113:521–538
Roddick JC (1990) 40Ar/39Ar evidence for te age of the New Quebec Crater, northern Quebec. In: Radiogenic age and isotopic studies, rep 3. Geol Surv Can Pap 89-2, pp 7–16
Roddick JC, Cliff RA, Rex DC (1980) The evolution of excess argon in Alpine biotites: a 40Ar/39Ar analysis. Earth Planet Sci Lett 48: 185–208
Savin SM, Epstein S (1970) The oxygen and hydrogen isotope geochemistry of ocean sediments and shales. Geochim Cosmochim Acta 34: 43–63
Smith CB (1983) Pb, Sr and Nd isotopic evidence for sources of Southern African Cretaceous kimberlites. Nature 30: 51–54
Smith CB, Allsopp HL, Kramers JD, Hutchinson G, Roddick JC (1985) Emplacement ages of Jurassic-Cretaceous South African kimberlites by the Rb-Sr method of phlogopite and whole-rock samples. Trans Geol Soc S Afr 88: 249–266
Smith CB, Gurney JJ, Harris JW, Otter ML, Kirkley MB, Jagoutz E (1991) Neodymium and Strontium isotope systematics of eclogite and websterite paragenesis inclusions from single diamonds, Finsch and Kimberley Pool, RSA. Geochim Cosmochim Acta 55: 2579–2590
Sobolev NV, Lavrentiev YG, Pokhilenko NP, Usova LV (1973) Chrome-rich garnets from the kimberlites of Yakutia and their paragenesis. Contrib Mineral Petrol 40: 39–52
Stauffer MR, Murkherjee AC, Koo J (1975) The Amisk group: an Aphebian (?) island arc deposit. Can J Earth Sci 12: 2021–2035
Tatsumoto M, Hegner E, Unruh DM (1987) Origin of the West Maui volcanic rocks inferred from Pb, Sr, and Nd isotopes and a multicomponent model for oceanic rocks. In: Volcanism in Hawaii. US Geol Surv Prof Pap. 1350, pp 723–757
Taylor BE (1986) Magmatic volatiles: isotopic variation of C, H, and S. In Valley JW, Taylor HP Jr, O'Neil JR (eds) Stable isotopes in high temperature geological processes. (Reviews in mineral 16) Mineral Soc Am, Washington, DC, pp 185–225
Turner G (1988) Hydrothermal fluids and argon isotopes in quartz veins and cherts. Geochim Cosmochim Acta 52: 1443–1448
Turner G, Bannon MP (1992) Argon isotope geochemistry of inclusion fluids from granite-associated mineral veins in south-west and northwest England. Geochim Cosmochim Acta 56: 227–243
Velde D (1975) Armacolite-Ti-phlogopite-diopside-analcite-bearing lamproites from Smoky Butte, Garfield County, Montana. Am Mineral 60: 566–576
Wasserberg GJ, Jacobsen SB, DePaolo DJ, McCulloch MT, Wen T (1981) Precise determination of Sm/Nd ratios, Sm and Nd isotopic abundances in standard solutions. Geochim Cosmochim Acta 45: 2311–2323
White WM (1985) Sources of oceanic basalts: radiogenic isotopic evidence. Geology 13: 115–118
York D (1969) Least squares fitting of a straight line with correlated errors. Earth Planet Sci Lett 5: 320–324
Zindler A, Hart SR (1986) Chemical geodynamics. Annu Rev Earth Planet Sci 14: 493–571
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Hegner, E., Roddick, J.C., Fortier, S.M. et al. Nd, Sr, Pb, Ar, and 0 isotopic systematics of Sturgeon Lake kimberlite, Saskatchewan, Canada: constraints on emplacement age, alteration, and source composition. Contrib Mineral Petrol 120, 212–222 (1995). https://doi.org/10.1007/BF00287118
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DOI: https://doi.org/10.1007/BF00287118