Contributions to Mineralogy and Petrology

, Volume 162, Issue 3, pp 547–563 | Cite as

Dynamics of melting beneath a small-scale basaltic system: a U-Th–Ra study from Rangitoto volcano, Auckland volcanic field, New Zealand

  • Lucy E. McGee
  • Christoph Beier
  • Ian E. M. Smith
  • Simon P. Turner
Original Paper

Abstract

The Auckland volcanic field is a Quaternary monogenetic basaltic field of 50 volcanoes. Rangitoto is the most recent of these at ~500 year BP and may mark a change in the behaviour of the field as it is the largest by an order of magnitude and is unusual in that it erupted magmas of alkalic then subalkalic basaltic composition in discrete events separated by ≤50 years. Major and trace element geochemistry together with Sr–Nd and U-Th–Ra isotopes provides the basis for modelling the melting conditions that brought about the eruption of two chemically different lavas with very little spatial or temporal change. Sr–Nd isotopes suggest that the source for both eruptions is similar with a slight degree of heterogeneity. The basalts show high 230Th-excess compared with comparable continental volcanic fields. We show that the alkalic basalts give evidence for lower degrees of partial melting, higher amounts of residual garnet, a longer melting column and lower melting and upwelling rates compared with the subalkalic basalts. The low upwelling rates (0.1–1.5 cm/year) modelled for both magmas do not suggest a plume or major upwelling in the mantle region beneath Auckland; therefore, we suggest localised convection due to relict movement from the active subduction system situated 400 km to the southeast. A higher porosity for the initial alkalic basalt is based on 226Ra-excesses, suggesting movement of melt by two different porosities: the initial melt travelling in fast high porosity channels from greater depths preserving a high 230Th-excess and the subsequent subalkalic magma travelling from a shallower depth through lower porosity diffuse channels preserving a high 226Ra-excess; this creates a negative array in (226Ra/230Th) versus (230Th/238U) space previously only seen in mid ocean ridge Basalt data. This mechanism suggests the Auckland volcanic field may operate by the presence of discrete melt batches that are able to move at different depths and speeds giving the field its erratic spatial and temporal pattern of eruptions, a type of behaviour that may have implications for the evolution of other continental volcanic fields worldwide.

Keywords

Monogenetic Auckland volcanic field U-series 226Ra-excess Two-porosity model 

Notes

Acknowledgments

This study has been funded by the Earthquake Commission through the DEVORA (DEtermining Volcanic Risk in Auckland) project. Andrew Needham provided samples and access to the Rangitoto dataset. Christoph Beier thanks Coopers PA for inspiration and was funded by a Feodor Lynen fellowship of the Alexander von Humboldt-Foundation. Lucy McGee appreciates the Australian wildlife and medical services for their participation during the labwork of this project. Simon Turner is supported by an Australian Research Council Professorial Fellowship. This work used instrumentation funded by ARC LIEF and DEST Systemic Infrastructure Grants, Macquarie University and Industry. We thank K.Sims and an unfortunately anonymous constructive reviewer whose comments and suggestions substantially improved the manuscript. This is contribution 706 from the Australian Research Council National Key Centre for the Geochemical Evolution and Metallogeny of Continents.

References

  1. Allen SR, Smith IE (1994) Eruption styles and volcanic hazard in the Auckland volcanic field, New Zealand. Geosci Rep Shizuoka Univ 20:5–14Google Scholar
  2. Asimow PD, Hirschmann MM, Stolper EM (2001) Calculation of peridotite partial melting from thermodynamic models of minerals and melts, IV. Adiabatic decompression and the composition and mean properties of mid-ocean ridge basalts. J Petrol 42(5):963–998CrossRefGoogle Scholar
  3. Asmerom Y, Edwards RL (1995) U-series isotopes evidence for the origin of continental basalts. Earth Planet Sci Lett 134:1–7CrossRefGoogle Scholar
  4. Beier C, Turner S, Plank T, White W (2010) A preliminary assessment of the symmetry of source composition and melting dynamics across the Azores plume. Geochem Geophys Geosyst 11(2):Q02004CrossRefGoogle Scholar
  5. Blondes MS, Reiners PW, Ducea MN, Singer BS, Chesley J (2008) Temporal-compositional trends over short and long time-scales in basalts of the big Pine volcanic field, California. Earth Planet Sci Lett 269:140–154CrossRefGoogle Scholar
  6. Blundy J, Wood B (2003) Mineral-melt partitioning of Uranium, Thorium and their daughters. In: Bourdon B, Henderson GM, Lundstrom C, Turner SP (eds) Uranium-series geochemistry. Reviews in mineralogy and geochemistry. Geochemical Society-Mineralogical Society of America, Washington, pp 59–123Google Scholar
  7. Bourdon B, Van Orman JA (2009) Melting of enriched mantle beneath Pitcairn seamounts: unusual U-Th-Ra systematics provide insights into melt extraction processes. Earth and Planetary Sci Lett 277:474–481CrossRefGoogle Scholar
  8. Bourdon B, Joron J-L, Claude-Ivanaj C, Allègre CJ (1998) U-Th-Pa-Ra systematics for the Grande Comore volcanics: melting processes in an upwelling plume. Earth Planet Sci Lett 164(1–2):119–133CrossRefGoogle Scholar
  9. Bourdon B, Turner SP, Ribe NM (2005) Partial melting and upwelling rates beneath the Azores from a U-series isotope perspective. Earth Planet Sci Lett 239(1–2):42–56CrossRefGoogle Scholar
  10. Brenna M, Cronin SJ, Smith IEM, Sohn YK, Nemeth K (2010) Mechanisms driving polymagmatic activity at a monogenetic volcano. Contributions to Mineralogy and Petrology, South KoreaGoogle Scholar
  11. Canon-Tapia E, Walker GPL (2004) Global aspects of volcanism: the perspectives of “plate tectonics” and “volcanic systems”. Earth-Sci Rev 66:163–182CrossRefGoogle Scholar
  12. Cheng H et al (2000) The half-lives of uranium-234 and thorium-230. Chem Geol 169(1–2):17–33CrossRefGoogle Scholar
  13. Connor CB, Conway FM (2000) Basaltic volcanic fields. In: Sigurdsson H (ed) Encyclopedia of volcanoes. Academic Press, San Diego, pp 331–343Google Scholar
  14. Connor CB, Hill BE (1995) Three nonhomogeneous Poisson models for the probabilty of basaltic volcanism: application to the Yucca mountain region, Nevada. J Geophys Res 100(B6):10107–10125CrossRefGoogle Scholar
  15. Cook C, Briggs RM, Smith IEM, Maas R (2005) Petrology and geochemistry of intraplate basalts in the South Auckland volcanic field, New Zealand: evidence for two coeval magma suites from distinct sources. J Petrol 46(3):473–503CrossRefGoogle Scholar
  16. Demidjuk Z et al (2007) U-series isotope and geodynamic constraints on mantle melting processes beneath the newer volcanic province in South Australia. Earth Planet Sci Lett 261(3–4):517–533CrossRefGoogle Scholar
  17. Eggins SM, Rudnick RL, McDonough WF (1998) The composition of peridotites and their minerals: a laser-ablation ICP-MS study. Earth Planet Sci Lett 154:53–71CrossRefGoogle Scholar
  18. Eichelberger JC, Izbekov PE, Browne BL (2006) Bulk chemical trends at arc volcanoes are not liquid lines of descent. Lithos 87:135–154CrossRefGoogle Scholar
  19. Elliott T (1997) Fractionation of U and Th during mantle melting: a reprise. Chem Geol 139:165–183CrossRefGoogle Scholar
  20. Elliott T, Spiegelman M (2003) Melt migration in oceanic crustal production: a U-series perspective. In: Rudnick RL (ed) Treatise of geochemistry, vol 3. Elsevier, New YorkGoogle Scholar
  21. Farmer GL et al (1995) Origin of late Cenozoic basalts at the Cima volcanic field, Mojave Desert, California. J Geophys Res 100(B5):8399–8415CrossRefGoogle Scholar
  22. Fujii T (1989) Genesis of mid-ocean ridge basalts. Geol Soc Lond, Special Publ 42(1):137–146CrossRefGoogle Scholar
  23. Garrison J, Davidson J, Reid M, Turner S (2006) Source versus differentiation controls on U-series disequilibria: insights from Cotopaxi Volcano, Ecuador. Earth Planet Sci Lett 244:548–565CrossRefGoogle Scholar
  24. Green DH (1973) Experimental melting studies on a model upper mantle composition at high pressure under water-saturated and water-undersaturated conditions. Earth Planet Sci Lett 19(1):37–53CrossRefGoogle Scholar
  25. Green DH, Ringwood AE (1967) The genesis of basaltic magmas. Contrib Miner Petrol 15(2):103–190CrossRefGoogle Scholar
  26. Hasenaka T, Carmichael ISE (1987) The cinder cones of Michoacan-Guanajuato, Central Mexico: petrology and chemistry. J Petrol 28(2):241–269Google Scholar
  27. Heming RF, Barnet PR (1986) The petrology and petrochemistry of the Auckland volcanic field. In: Smith IE (ed) Late Cenozoic volcanism in New Zealand. The Royal Society of New Zealand, pp 64–75Google Scholar
  28. Heyworth Z et al (2007) 238U-230Th-226Ra-210Pb constraints on the genesis of high-Mg andesites at White Island, New Zealand. Chem Geol 243(1–2):105–121CrossRefGoogle Scholar
  29. Hirose K, Kushiro I (1993) Partial melting of dry perdiotites at high pressures: determination of compositions of melts segregated from peridotite using aggregates of diamond. Earth Planet Sci Lett 114:477–489CrossRefGoogle Scholar
  30. Hofmann AW (1997) Mantle geochemistry: the message from oceanic volcanism. Nature 385:219–229CrossRefGoogle Scholar
  31. Hsu C, Chen J (1998) Geochemistry of late Cenozoic basalts from Wudalianchi and Jingpohu areas, Heilongjiang province, northeast China. J Asian Earth Sci 16(4):385–405CrossRefGoogle Scholar
  32. Huang YM, Hawkesworth C, van Calsteren P, Smith I, Black P (1997) Melt generation models for the Auckland volcanic field, New Zealand: constraints from U-Th isotopes. Earth Planet Sci Lett 149(1–4):67–84CrossRefGoogle Scholar
  33. Huang Y, Hawkesworth C, Smith I, van Calsteren P, Black P (2000) Geochemistry of late Cenozoic basaltic volcanism in Northland and Coromandel, New Zealand: implications for mantle enrichment processes. Chem Geol 164:219–238CrossRefGoogle Scholar
  34. Iwamori H (1994) 238U–230Th—226Ra and 235U–231 Pa disequilibria produced by mantle melting with porous and channel flows. Earth Planet Sci Lett 125(1–4):1–16CrossRefGoogle Scholar
  35. Jull M, Kelemen PB, Sims K (2002) Consequences of diffuse and channelled porous melt migration on uranium series disequilibria. Geochim Cosmochim Acta 66(23):4133–4148CrossRefGoogle Scholar
  36. Kelemen PB, Hirth G, Shimizu N, Spiegelman M, Dick HJB (1997) A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges. Philosophical transactions: mathematical. Phys Eng Sci 355(1723):283–318Google Scholar
  37. Lee C-TA, Luffi P, Plank T, Dalton H, Leeman WP (2009) Constraints on the depths and temperatures of basaltic magma generation on earth and other terrestrial planets using new thermobarometers for mafic magmas. Earth Planet Sci LettGoogle Scholar
  38. Liang Y (2008) Simple models for dynamic melting in an upwelling heterogeneous mantle column: analytical solutions. Geochim Cosmochim Acta 72:3804–3821CrossRefGoogle Scholar
  39. Lundstrom C (2000) Models of U-series disequilibria generation in MORB: the effects of two scales of melt porosity. Phys Earth Planet Interiors 121:189–204CrossRefGoogle Scholar
  40. Marsh BD (1989) Magma chambers. Annu Rev Earth Planet Sci Lett 17:439–474CrossRefGoogle Scholar
  41. McDonough WF, Sun S-S (1995) The composition of the earth. Chem Geol 120:223–253CrossRefGoogle Scholar
  42. Mckenzie D (1985) The extraction of magma from the crust and mantle. Earth Planet Sci Lett 74:81–91CrossRefGoogle Scholar
  43. Molloy C, Shane P, Augustinus P (2009) Eruption recurrence rates in a basaltic volcanic field based on tephra layers in maar sediments: implications for hazards in the Auckland volcanic field. GSA BulletinGoogle Scholar
  44. Needham AJ, Lindsay JM, Smith IEM, Augustinus PA, Shane PA (2010) Sequential eruption of alkaline and sub-alkaline magmas from a small monogenetic volcano in the Auckland volcanic field, New Zealand. J Volcanol Geotherm ResGoogle Scholar
  45. Peate DW, Hawkesworth CJ (2005) U series disequilibria: insights into mantle melting and the timescales of magma differentiation. Rev Geophys 43Google Scholar
  46. Prytulak J, Elliott T (2009) Determining melt productivity of mantle sources from 238U–230Th and 235U–231 Pa disequilibria; an example from Pico Island, Azores. Geochim Cosmochim Acta 73(7):2103–2122CrossRefGoogle Scholar
  47. Reiners PW (2002) Temporal-compositional trends in intraplate basalt eruptions: implications for mantle heterogeneity and melting processes. Geochem Geophys Geosyst 3(2)Google Scholar
  48. Robinson JAC, Wood BJ (1998) The depth of the spinel to garnet transition at the peridotite solidus. Earth Planet Sci Lett 164(1–2):277–284CrossRefGoogle Scholar
  49. Sims KWW, Hart SR (2006) Comparison of Th, Sr, Nd and Pb isotopes in oceanic basalts: implications for mantle heterogeneity and magma genesis. Earth Planet Sci Lett 245:743–761CrossRefGoogle Scholar
  50. Sims KWW et al (1999) Porosity of the melting zone and variations in the solid mantle upwelling rate beneath Hawaii: inferences from 238U–230Th-226Ra and 235U–231 Pa disequilibria. Geochim Cosmochim Acta 63(23–24):4119–4138CrossRefGoogle Scholar
  51. Sims KWW et al (2002) Chemical and isotopic constraints on the generation and transport of magma beneath the East Pacific Rise. Geochim Cosmochim Acta 66(19):3481–3504CrossRefGoogle Scholar
  52. Sims KWW et al (2003) Aberrant youth: chemical and isotopic constraints on the origin of off-axis lavas from the East Pacific rise, 9°–10°N. Geochem Geophys Geosyst 4(10)Google Scholar
  53. Sims KWW et al (2008) An inter-laboratory assessment of the thorium isotopic composition of synthetic and rock reference materials. Geostandards Geoanal Res 32(1):65–91CrossRefGoogle Scholar
  54. Smith IEM, Blake S, Wilson CJN, Houghton BF (2008) Deep-seated fractionation during the rise of a small-volume basalt magma batch: Crater Hill, Auckland, New Zealand. Contrib Mineral Petrol 155(4):511–527CrossRefGoogle Scholar
  55. Smith IEM, Stewart RB, Price RC, Worthington TJ (2009) Are arc-type rocks the products of magma crystallisation? Observations from a simple oceanic arc volcano. Journal of Volcanology and Geothermal Research, Kermadec ArcGoogle Scholar
  56. Spiegelman M, Elliott T (1993) Consequences of melt transport for uranium series disequilibrium in young lavas. Earth Planet Sci Lett 118:1–20CrossRefGoogle Scholar
  57. Stracke A, Hofmann AW, Hart SR (2005) FOZO, HIMU and the rest of the mantle zoo. Geochem Geophys Geosyst 6. doi: 10.1029/2004GC000824
  58. Stracke A, Bourdon B, McKenzie D (2006) Melt extraction in the Earth’s mantle: constraints from U-Th-Pa-Ra studies in oceanic basalts. Earth Planet Sci Lett 244(1–2):97–112CrossRefGoogle Scholar
  59. Strong M, Wolff J (2003) Compositional variations within scoria cones. Geology 31(2):143–146CrossRefGoogle Scholar
  60. Thomas LE, Hawkesworth CJ, Van Calsteren P, Turner SP, Rogers NW (1999) Melt generation beneath ocean islands: a U-Th-Ra isotope study from Lanzarote in the Canary Islands. Geochim Cosmochim Acta 63(23–24):4081–4099CrossRefGoogle Scholar
  61. Turner S, Bourdon B, Hawkesworth C, Evans P (2000) 226Ra-230Th evidence for multiple dehydration events, rapid melt ascent and the time scales of differentiation beneath the Tonga-Kermadec arc. Earth Planet Sci Lett 179:581–593CrossRefGoogle Scholar
  62. Turner S, Evans P, Hawkesworth C (2001) Ultrafast source-to-surface movement of melt at island arcs from 226Ra-230Th systematics. Science 292:1363–1366CrossRefGoogle Scholar
  63. Valentine GA, Perry FV (2007) Tectonically controlled, time-predictable basaltic volcanism from a lithospheric mantle source (central Basin and Range Province, USA). Earth Planet Sci Lett 261:201–216CrossRefGoogle Scholar
  64. Williams RW, Gill JB (1989) Effects of partial melting on the uranium decay series. Geochim Cosmochim Acta 53:1607–1619CrossRefGoogle Scholar
  65. Zhang M, Suddaby P, Thompson RN, Thirlwall MF, Menzies MA (1995) Potassic volcanic rocks in NE China: geochemical constraints on mantle source and magma genesis. J Petrol 36(5):1275–1303Google Scholar
  66. Zou H et al (2003) Constraints on the origin of historic potassic basalts from northeast China by U-Th disequilibrium data. Chem Geol 200:189–201CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Lucy E. McGee
    • 1
  • Christoph Beier
    • 2
    • 3
  • Ian E. M. Smith
    • 1
  • Simon P. Turner
    • 2
  1. 1.School of EnvironmentUniversity of AucklandAucklandNew Zealand
  2. 2.GEMOC, Department of Earth and Planetary SciencesMacquarie UniversitySydneyAustralia
  3. 3.GeoZentrum NordbayernUniversität Erlangen-NürnbergErlangenGermany

Personalised recommendations