Advertisement

Contributions to Mineralogy and Petrology

, Volume 164, Issue 4, pp 677–691 | Cite as

Timescales of convection in magma chambers below the Mid-Atlantic ridge from melt inclusions investigations

  • Aurélia Colin
  • François Faure
  • Pete Burnard
Original Paper

Abstract

Closed hopper and complex swallowtail morphologies of olivine microcrysts have been described in the past in both mid-oceanic ridge basalts and subaerial tholeitic volcanoes and indicate fluctuations in magma undercooling. We describe similar morphologies in a Mid-Atlantic ridge pillow basalt (sample RD87DR10), and in addition we estimate the duration of temperature fluctuations required to produce these textures as follows: (1) Pairs of melt inclusions are arranged symmetrically around the centre of hopper crystals and each pair represents a heating–cooling cycle. Using the literature olivine growth rates relevant to the observed morphologies, and measuring the distance between two successive inclusions, we estimate the minimum time elapsed during one convection cycle. (2) The major element composition of melt inclusions (analysed by electron microprobe) was found to be in the range of the boundary layer measured in the glass surrounding the olivines, irrespective of their size. Several major elements demonstrate that this boundary layer results from rapid quenching on the seafloor, and not from crystal growth at depth, implying the inclusions had the same composition as the surrounding magma when they were sealed. Using diffusivity of slow diffusing elements such as Al2O3, we estimate the minimum time required for inclusion formation. These two independent approaches give concordant results: each cooling–heating cycle lasted between a few minutes and 1 h minimum. Thus, these crystals probably recorded thermal convection in small magmatic bodies (a dyke or shallow magma chamber) during the last hour or hours before eruption.

Keywords

Magma chamber Convection timescale Olivine microcryst morphology Melt inclusion Mid-Atlantic ridge 

Notes

Acknowledgments

François Faure thanks L’Agence Nationale de la Recherche for financial support (grant ANR-07-BLAN-0130-CSD6, MIME). We thank Fidel Costa and an anonymous reviewer for constructive comments which improved the final manuscript. This is CRPG contribution number 2169.

Supplementary material

410_2012_764_MOESM1_ESM.xls (16.8 mb)
Supplementary material 1 (XLS 17251 kb)
410_2012_764_MOESM2_ESM.docx (15 kb)
Supplementary material 2 (DOCX 14 kb)

References

  1. Armienti P, Innocenti F et al (1991) Crystal population density in not stationary volcanic systems: estimate of olivine growth rate in basalts of Lanzarote (Canary Islands). Mineral Petrol 44(3):181–196CrossRefGoogle Scholar
  2. Canales JP, Nedimovic MR, Kent GM, Carbotte SM, Detrick RS (2009) Seismic reflection images of a near-axis melt sill within the lower crust at the Juan de Fuca ridge. Nature 460:89–100CrossRefGoogle Scholar
  3. Chen Y, Zhang Y (2008) Olivine dissolution in basaltic melt. Geochim et Cosmochim Acta 72:4756–4777CrossRefGoogle Scholar
  4. Costa F, Chakraborty S, Dohmen R (2003) Diffusion coupling between trace and major elements and a model for calculation of magma residence times using plagioclase. Geochim Cosmochim Acta 67:2189–2200CrossRefGoogle Scholar
  5. Costa F, Coogan LA, Chakraborty S (2010) The time scales of magma mixing and mingling involving primitive melts and melt-mush interaction at mid-ocean ridges. Contrib Mineral Petrol 159:371–387CrossRefGoogle Scholar
  6. Davis MJ, Ihinger PD (1998) Heterogeneous crystal nucleation on bubbles in silicate melt. Am Mineral 83:1008–1015Google Scholar
  7. Donaldson CH (1975) Calculated diffusion coefficients and the growth rate of olivine in a basalt magma. Lithos 8(2):163–174CrossRefGoogle Scholar
  8. Donaldson CH (1976) An experimental investigation of olivine morphology. Contrib Mineral Petrol 57:187–213CrossRefGoogle Scholar
  9. Donaldson CH (1979) An experimental investigation of the delay in nucleation of olivine in Mafic Magmas. Contrib Mineral Petrol 69:21–32CrossRefGoogle Scholar
  10. Dvorak JJ, Dzurisin D (1997) Volcano geodesy: The search for magma reservoirs and the formation of eruptive vents. Rev Geophys 35:343–384CrossRefGoogle Scholar
  11. Faure F, Schiano P (2004) Crystal morphologies in pillow basalts: implications for mid-ocean ridge processes. Earth Planet Sci Lett 220:331–344CrossRefGoogle Scholar
  12. Faure F, Trolliard G, Nicollet C, Montel JM (2003) A developmental model of olivine morphology as a function of the cooling rate and the degree of undercooling. Contrib Mineral Petrol 145:251–263CrossRefGoogle Scholar
  13. Faure F, Schiano P, Trolliard G, Nicollet C, Soulestin B (2007) Textural evolution of polyhedral olivine experiencing rapid cooling rates. Contrib Mineral Petrol 153:405–416CrossRefGoogle Scholar
  14. Jambon A, Lussiez P, Clocchiatti R, Weisz J, Hernandez J (1992) Olivine growth rates in a tholeiitic basalt: An experimental study of melt inclusions in plagioclase. Chem Geol 96:277–287CrossRefGoogle Scholar
  15. Kirkpatrick R (1978) Processes of crystallization in pillow basalts, hole 396B, DSDP LEG 46. In: Dmitriev L, Heirtzler J et al (eds) Initial reports of the Deep Sea Drilling Project 46. US Govt Print Office, Washington, pp 271–282Google Scholar
  16. Kirkpatrick RJ (1983) Theory of nucleation in silicate melts. Am Mineral 68:66–77Google Scholar
  17. Kohut E, Nielsen RL (2004) Melt inclusion formation mechanisms and compositional effects in high-An feldspar and high-Fo olivine in anhydrous mafic silicate liquids. Contrib Mineral Petrol 147(6):684–704CrossRefGoogle Scholar
  18. Kress VC, Ghiorso MS (1995) Multicomponent diffusion in basaltic melts. Geochim Cosmochim Acta 59:313–324CrossRefGoogle Scholar
  19. Marsh BD (1989) On Convective Style and Vigor in Sheet-like Magma Chambers. J Petrol 30:479–530Google Scholar
  20. Pack A, Palme H (2003) Partitioning of Ca and Al between forsterite and silicate melt in dynamic systems with implications for the origin of Ca, Al-rich forsterites in primitive meteorites. Meteorit Planet Sci 38(8):1263–1281CrossRefGoogle Scholar
  21. Roedder E (1984) Fluid inclusions. Rev Mineral 12:413–439Google Scholar
  22. Rubin KH, van der Zander I, Smith MC, Bergmanis EC (2005) Minimum speed limit for ocean ridge magmatism from Pb-210-Ra-226-Th-230 disequilibria. Nature 437:534–538CrossRefGoogle Scholar
  23. Schiano P, Provost A, Clocchiatti R, Faure F (2006) Transcrystalline melt migration and Earth’s mantle. Science 314:970–974CrossRefGoogle Scholar
  24. Singh SC, Crawford WC, Carton H, Seher T, Combier V, Cannat M, Canales JP, Dusunur D, Escartin J, Miranda JM (2006) Discovery of a magma chamber and faults beneath a Mid-Atlantic Ridge hydrothermal field. Nature 442:1029–1032CrossRefGoogle Scholar
  25. Turner S, Evans P, Hawkesworth C (2001) Ultrafast source-to-surface movement of melt at island arcs from Ra-226-Th-230 systematics. Science 292:1363–1366CrossRefGoogle Scholar
  26. Welsch B, Faure F, Bachelery P, Famin V (2009) Microcrysts record transient convection at Piton de la Fournaise Volcano (La Reunion hotspot). J Petrol 50:2287–2305CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Aurélia Colin
    • 1
    • 2
    • 3
  • François Faure
    • 1
    • 2
  • Pete Burnard
    • 1
    • 2
  1. 1.Université de LorraineCentre de Recherches Pétrographiques et Géochimiques, UPR 2300Vandoeuvre les NancyFrance
  2. 2.CNRSCentre de Recherches Pétrographiques et GéochimiquesVandoeuvre les NancyFrance
  3. 3.Faculty of Earth and Life SciencesVrije UniversiteitAmsterdamNetherlands

Personalised recommendations