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Constraints on HIMU and EM by Sr and Nd isotopes re-examined

Abstract

Sr and Nd isotopes together with trace elements for ocean island basalts in the Polynesian region have been analyzed in order to investigate the origin of the HIMU and EM sources. Both whole rocks and cpx phenocrysts were analyzed for isotopic composition. Cpx samples from HIMU islands show quite uniform 87Sr/86Sr ratios (~0.70274), while leached and unleached whole rock samples show variable and higher 87Sr/86Sr than those of cpx samples. These results suggest that even leached whole rock samples have been affected by secondary contaminations of sea water. On the other hand, cpx preserves a pristine isotopic signature with minimal secondary effects.

Using only the cpx analyses, HIMU form a vertical linear trend in the Sr-Nd isotope diagram with small variation in εNd (+3.3~+5.5) and constant 87Sr/86Sr. This trend is explained by a mixing of the HIMU end-member and the MORB source. Since εNd of the HIMU end-member is constrained to be less than +3.3, the HIMU source should include former sediment added to oceanic crust. To explain the vertical nature of the mixing trend, the HIMU end-member should have similar Rb/Sr to the MORB source, or much lower Sr/Nd ratio than the MORB source, which favors a mixing model between extensively dehydrated oceanic crust and sediment as the HIMU source. The correlation between εNd and trace element ratios such as Pb/Ta also supports the model.

References

  1. Allègre, C. J., O. Brévart, B. Dupré, and J. F. Minster, Isotopic and chemical effects produced in a continuously differentiating convecting earth mantle, Philos. Trans. R. Soc. Lond., A297, 447–477, 1980.

  2. Barsczus, H. G., G. Guille, R. Maury, C. Chauvel, and H. Guillou, Two magmatic sources at Rurutu Island (Austral Islands, French Polynesia) and the Austral “Hotline”, EOS, 75, 323, 1994.

  3. Ben Othman, D., W. M. White, and J. Patchett, The geochemistry of marine sediments, island arc magma genesis, and crust-mantle recycling, Earth Planet. Sci. Lett., 94, 1–21, 1989.

  4. Chauvel, C., A. W. Hofmann, and P. Vidal, HIMU-EM: The French Polynesian connection, Earth Planet. Sci. Lett., 110, 99–119, 1992.

  5. Chauvel, C., S. L. Goldstein, and A. H. Hofmann, Hydration and dehydration of oceanic crust controls Pb evolution in the mantle, Chem. Geol., 126, 65–75, 1995.

  6. Chauvel, C., W. McDonough, G. Guille, R. Maury, and R. Duncan, Contrasting old and young volcanism in Rurutu Island, Austral chain, Chem. Geol., 139, 125–143, 1997.

  7. Dostal, J., C. Dupuy, and P. Dudoignon, Distribution of boron, lithium and beryllium in oceanic island basalts from French Polynesia: implications for the B/Be and Li/Be ratios as tracers of subducted components, Mineral. Magazine, 60, 563–580, 1996.

  8. Duncan, R. A. and I. McDougall, Linear volcanism in French Polynesia, J. Volcanol. Geotherm. Res., 1, 197–227, 1976.

  9. Dziewonski, A. M., Mapping the lower mantle: Determination of lateral heterogeneity in P velocity up to degree and order 6, J. Geophys. Res., 89, 5929–5952, 1984.

  10. Eiler, J. M., K. A. Farley, J. W. Valley, E. Hauri, H. Craig, S. R. Hart, and E. M. Stolper, Oxygen isotope variations in ocean island basalt phenocrysts, Geochim. Cosmochim. Acta, 61, 2281–2293, 1997.

  11. Fukao, Y., Seismic tomogram of the Earth’s mantle: geodynamic implications, Nature, 258, 625–630, 1992.

  12. Graham, D. W., S. E. Humphris, W. J. Jenkins, and M. D. Kurz, Helium isotope geochemistry of some volcanic rocks from Saint Helena, Earth Planet. Sci. Lett., 110, 121–131, 1992.

  13. Green, T. H., Experimental studies of trace-element partitioning applicable to igneous petrogenesis—Sedona 16 years later, Chem. Geol., 117, 1–36, 1994.

  14. Green, T. H. and N. J. Pearson, Rare earth element partitioning between clinopyroxene and silicate liquid at moderate to high pressure, Contrib. Mineral. Petrol., 91, 24–36, 1985.

  15. Halliday, A. N., D.-C. Lee, S. Tommasini, G. R. Davies, C. R. Paslick, J. G. Fitton, and D. E. James, Incompatible trace elements in OIB and MORB and source enrichment in the sub-oceanic mantle, Earth Planet. Sci. Lett., 133, 379–395, 1995.

  16. Hanyu, T. and I. Kaneoka, The uniform and low 3He/4He ratios of HIMU basalts as evidence for their origin as recycled materials, Nature, 390, 273–276, 1997.

  17. Hanyu, T., I. Kaneoka, and K. Nagao, Noble gas study of HIMU and EM ocean island basalts in the Polynesian region, Geochim. Cosmochim. Acta, 63, 1181–1201, 1999.

  18. Hauri, E. H. and S. R. Hart, Re-Os isotope systematics of HIMU and EMII oceanic island basalts from the south Pacific Ocean, Earth Planet. Sci. Lett., 114, 353–371, 1993.

  19. Hémond, C., C. W. Devey, and C. Chauvel, Source compositions and melting processes in the Society and Austral plumes (South Pacific Ocean): Element and isotope (Sr, Nd, Pb, Th) geochemistry, Chem. Geol., 115, 7–45, 1994.

  20. Hofmann, A. W., Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust, Earth Planet. Sci. Lett., 90, 297–314, 1988.

  21. Hofmann, A. W., Mantle geochemistry: the message from oceanic volcanism, Nature, 385, 219–229, 1997.

  22. Hofmann, A. W. and W. M. White, Mantle plumes from ancient oceanic crust, Earth Planet. Sci. Lett., 57, 421–436, 1982.

  23. Keppler, H., Constraints from partitioning experiments on the composition of subduction-zone fluids, Nature, 380, 237–240, 1996.

  24. Kogiso, T., Y. Tatsumi, G. Shimoda, and H. G. Barsczus, High μ (HIMU) ocean basalts in southern Polynesia: New evidence for whole mantle scale recycling of subducted oceanic crust, J. Geophys. Res., 102, 8085–8103, 1997.

  25. Makishima, A. and E. Nakamura, Suppression of matrix effects in ICP-MS by high power operation of ICP: Application to precise determination of Rb, Sr, Y, Cs, Ba, REE, Pb, Th and U at ng g−1 levels in milligram silicate samples, Geostand. News Lett., 21, 307–319, 1997.

  26. Makishima, A., E. Nakamura, and T. Nakano, Determination of zirconium, niobium, hafnium and tantalum at ng g−1 levels in geological materials by direct nebulization of back-extracted sample HF solutions into FI-ICPMS, Geostands Newslett., 23, 7–20, 1999.

  27. McDonough, W. F. and C. Chauvel, Sample contamination explains the Pb isotopic composition of some Rurutu island and Sasha seamount basalts, Earth Planet. Sci. Lett., 105, 397–404, 1991.

  28. McDonough, W. F. and S.-S. Sun, The composition of the Earth, Chem. Geol., 120, 223–253, 1995.

  29. McKenzie, D. and R. K. O’Nions, Mantle reservoirs and ocean island basalts, Nature, 301, 229–231, 1983.

  30. McKenzie, D. and R. K. O’Nions, Partial melt distributions from inversion of rare earth element concentrations, J. Petrol., 32, 1021–1091, 1991.

  31. McNutt, M. K. and A. V. Judge, The superswell and mantle dynamics beneath the South Pacific, Science, 248, 969–975, 1990.

  32. McNutt, M. K., D. W. Caress, J. Reynolds, K. A. Jordahl, and R. A. Duncan, Failure of plume theory to explain midplate volcanism in the southern Austral islands, Nature, 389, 479–482, 1997.

  33. Michard, A., F. Albarède, G. Michard, J. F. Minster, and J. L. Charlou, Rare-earth elements and uranium in high-temperature solutions from East Pacific Rise hydrothermal vent field (13°N), Nature, 303, 795–797, 1983.

  34. Nakamura, Y. and M. Tatsumoto, Pb, Nd, and Sr isotopic evidence for a multicomponent source for rocks of Cook-Austral Islands and heterogeneities of mantle plumes, Geochim. Cosmochim. Acta, 52, 2909–2924, 1988.

  35. Palacz, Z. A. and D. Saunders, Coupled trace element and isotope enrichment in the Cook-Austral-Samoa islands, southwest Pacific, Earth Planet. Sci. Lett., 79, 270–280, 1986.

  36. Reisberg, L., A. Zindler, F. Marcantonio, W. White, D. Wyman, and B. Weaver, Os isotope systematics in ocean island basalts, Earth Planet. Sci. Lett., 120, 149–167, 1993.

  37. Roy-Barman, M. and C. J. Allègre, 187Os/186Os in oceanic island basalts: tracing oceanic crust recycling in the mantle, Earth Planet. Sci. Lett., 129, 145–161, 1995.

  38. Saal, A. E., S. R. Hart, N. Shimizu, E. H. Hauri, and G. D. Layne, Pb isotopic variability in melt inclusions from oceanic island basalts, Polynesia, Science, 282, 1481–1484, 1998.

  39. Shibata, T. and E. Nakamura, Across-arc variations of isotope and trace element compositions from Quaternary basaltic volcanic rocks in northeastern Japan: Implications for interaction between subducted oceanic slab and mantle wedge, J. Geophys. Res., 102, 8051–8064, 1997.

  40. Sun, S.-S. and W. F. McDonough, Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes, in Magmatism in the Ocean Basins, edited by A. D. Saunders, M. J. Norry, pp. 313–345, Geol. Soc. Spec. Pub. No. 42, 1989.

  41. Sylvester, P. J., I. H. Campbell, and D. A. Bowyer, Niobium/uranium evidence for early formation of the continental crust, Science, 275, 521–523, 1997.

  42. Turner, D. L. and R. D. Jarrard, K-Ar dating of the Cook-Austral island chain: a test of the hot-spot hypothesis, J. Volcanol. Geotherm. Res., 12, 187–220, 1982.

  43. Vidal, P. and L. Dosso, Core formation: Catastrophic or continuous? Sr and Pb isotope constraints, Geophys. Res. Lett., 5, 169–172, 1978.

  44. Vidal, P., C. Chauvel, and R. Brousse, Large mantle heterogeneity beneath French Polynesia, Nature, 307, 536–538, 1984.

  45. Vollmer, R., Earth degassing, mantle metasomatism, and isotopic evolution of the mantle, Geology, 11, 452–454, 1983.

  46. Weaver, B. L., The origin of ocean island basalt end-member compositions: trace element and isotopic constraints, Earth Planet. Sci. Lett., 104, 381–397, 1991.

  47. Woodhead, J. D., Extreme HIMU in an oceanic setting: the geochemistry of Mangaia Island (Polynesia), and temporal evolution of the Cook-Austral hotspot, J. Volcanol. Geotherm. Res., 72, 1–19, 1996.

  48. Yoshikawa, M. and E. Nakamura, Precise isotope determination of trace amounts of Sr in magnesium-rich samples, J. Min. Petr. Econ. Geol., 88, 548–561, 1993.

  49. Zindler, A. and S. Hart, Chemical geodynamics, Ann. Rev. Earth Planet. Sci., 14, 493–571, 1986.

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Correspondence to Takeshi Hanyu.

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Hanyu, T., Nakamura, E. Constraints on HIMU and EM by Sr and Nd isotopes re-examined. Earth Planet Sp 52, 61–70 (2000). https://doi.org/10.1186/BF03351614

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Keywords

  • Earth Planet
  • Rock Sample
  • Oceanic Crust
  • 86Sr
  • Mantle Plume