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Volatiles in Magmas

My work on investigation of the pre-eruptive volatile content of rhyolitic magmas has involved microbeam analyses of melt inclusions in phenocrysts. This work has focussed on direct determination of the H2O, Cl, F, and S contents of pre-eruptive magmas with the goal of furthering knowledge on the effects of magmatic volatiles on the dynamics of explosive eruptions, as well as a better understanding of the atmospheric impact of explosive volcanism. Research has centered on the eruptive products of the Bishop, Bandelier and Taupo magma chambers, but also includes work on Mt. Erebus, an active volcano in Antarctica.


  1. DUNBAR, N.W. AND HERVIG, R.L., 1992A. Petrogenesis and volatile stratigraphy of the Bishop Tuff: Evidence from melt inclusion analysis. J. Geophys. Res., 97, 15129-15150. ABSTRACT
  2.  DUNBAR, N.W. AND HERVIG, R.L., 1992B. Volatile and trace element composition of melt inclusions from the Lower Bandelier Tuff: Implications for eruptive style and magma chamber processes. J. Geophys. Res., 97, 15151-15170.ABSTRACT
  3.  DUNBAR, N.W., HERVIG, R.L., and KYLE, P.R., 1989. Determination of pre-eruptive H2O, F and Cl contents of silicic magmas using melt inclusions: Examples from Taupo volcanic center, New Zealand. Bull. Volcanol., 51, 177-184. ABSTRACT
  4.  DUNBAR, N.W. AND KYLE, P.R., 1992. Volatile contents of obsidian clasts in tephra from the Taupo Volcanic Zone, New Zealand: Implications to eruptive processes. J. Volcanol. Geotherm. Res., 49, 127-145.ABSTRACT
  5.  DUNBAR, N.W. AND KYLE, P.R., 1993. Lack of volatile gradient in the Taupo plinian-ignimbrite transition: Evidence from melt inclusion analysis. Am. Mineral., 78, 612-618. ABSTRACT
  6. ESCHENBACHER, A. J., P. R. KYLE, J. LOWENSTERN, and N. W. DUNBAR, 1998, Melt inclusion investigation of the volatile behavior of fractionating, alkaline, magma, Mount Erebus, Ross Island, Antarctica: PACROFI VII.
  7. ESCHENBACHER, A. J., P. R. KYLE, J. LOWENSTERN, and N. W. DUNBAR, 1998, Pre-eruptive volatile contents of an evolving, alkaline, magma system, Mount Erebus, Ross Island, Antarctica: IAVCEI International Volcanological Congress, p. 18.
  8.  HERVIG, R.L., DUNBAR, N.W., WESTRICH, H.R., and KYLE, P.R., 1989. Pre-eruptive water content of rhyolitic magmas as determined by ion microprobe analyses of melt inclusions in phenocrysts. J. Volcanol. Geotherm. Res., 36, 293-302.
  9. WINICK, J., DUNBAR, N., and MCINTOSH, W., 2000, Melt inclusion hosted excess argon (40ArE) in the quartz crystals of the Bishop and Bandelier magma systems: New Mexico Geology, 22, 38. ABSTRACT