Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-26T08:50:21.612Z Has data issue: false hasContentIssue false

The 1875 eruption of Askja volcano, Iceland: combined fractional crystallization and selective contamination in the generation of rhyolitic magma

Published online by Cambridge University Press:  05 July 2018

R. Macdonald
Affiliation:
Department of Environmental Science, University of Lancaster, Lancaster LA1 4YQ, U.K.
R. S. J. Sparks
Affiliation:
Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, U.K.
H. Sigurdsson
Affiliation:
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, U.S.A.
D. P. Mattey
Affiliation:
Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, U.K.
D. W. McGarvie
Affiliation:
Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, U.K.
R. L. Smith
Affiliation:
U.S. Geological Survey, 2943C Fulton Avenue, Sacramento, CA 95821, U.S.A.

Abstract

Major and trace element and Sr, Nd and O isotopic data are presented for ferrobasalts, icelandites, rhyolites, mixed pumices and silicic xenoliths of the 1875 eruption of Askja. Trace element modelling and Sr and Nd data largely confirm previous major element calculations that fractional crystallization was dominant in the generation of the basalt-ferrobasalt-icelandite-rhyolite suite. Relative enrichment in Rb (and Th and U?), depletion in Cs, and low values of δ18O/16O, in the rhyolites are not explained by this mechanism alone. The silicic magmas were selectively contaminated by diffusion from partially molten granitic wall rocks, now found as xenoliths in the eruptive products, the process being particularly marked by lower δ18O and Cs/Rb ratios in the rhyolites than in the associated basalts. This is the first record of a combined fractional crystallization-selective contamination process in an Icelandic silicic complex.

Type
Petrology
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Arth, J.G. (1976) J. Res. U.S. Geol. Surv., 4, 41-7Google Scholar
Bacon, C.R., Macdonald, R., Smith, R.L., and Baedecker, P.A. (1981) J. Geophys. Res., 86, 10223-41.Google Scholar
Benjamin, T., Heuser, W.R., and Burnett, D.S. (1978) Proc. Lunar Planet. Sci. Conf. 9th, 1393-406.Google Scholar
Benjamin, T., Heuser, W.R., and Burnett, D.S. and Seitz, M.G. (1980) Geochim. Cosmochim. Acta, 44, 1251-64Google Scholar
Borthwick, J. and Harmon, R.S. (1982) Ibid. 46, 1665-8.Google Scholar
Carlson, C.W., Lugmair, G.W., and MacDougall, J.D. (1981) Ibid. 45, 2483-99.Google Scholar
Carmichael, I.S. E. (1964) J. Petrol., 5, 435-60.Google Scholar
Clague, D.A. and Frey, F.A. (1982) Ibid. 23, 447-504.Google Scholar
Condomines, M., Grönvold, K., Hooker, P.J., Muehlenbachs, K., O'Nions, R.K., Oskarsson, N., and Oxburgh, E.R. (1983) Earth Planet. Sci. Lett., 66, 125-36Google Scholar
Cox, K.G. and Hawkesworth, C.J. (1985) J. Petrol., 26, 355-77Google Scholar
Epstein, S., Sharp, R.P., and Gow, A.J. (1970) Science, 168, 1570-2Google Scholar
Garlick, G.D., Macgregor, I.D., and Vogel, D.E. (1971) Ibid. 172, 1025-7.Google Scholar
Gottfried, D., Greenland, L.P., and Campbell, E.Y. (1968) Geochim. Cosmochim. Acta, 32, 925-47Google Scholar
Harris, C. (1983) J. Petrol., 24, 424-70Google Scholar
Hattori, K. and Muehlenbachs, K. (1982) J. Geophys. Res., 87, 6559-65Google Scholar
Henderson, P. (1982) Inorganic Geochemistry. Oxford, Pergamon, 353 pp.Google Scholar
Hildreth, W. (1981) J. Geophys. Res., 86, 10153-92Google Scholar
Irvine, T.N. and Baragar, W.R. A. (1971) Can. J. Earth Sci. 9, 523–48.Google Scholar
Irving, A.J. (1978) Geochim. Cosmochim. Aeta, 42, 743-70Google Scholar
Larsen, G. and Thorarinsson, S. (1977) Jokull, 27, 28-46Google Scholar
Macdonald, R., Smith, R.L., and Thomas, J.E. (in prep.) U.S. Geol. Surv. Prof. Paper. Google Scholar
Muehlenbachs, K. (1973) Carnegie Inst. Wash. Yearb., 72, 593-7Google Scholar
Muehlenbachs, K. and Byerly, G. (1982) Contrib. Mineral. Petrol., 79, 76-9Google Scholar
Muehlenbachs, K. Anderson, A.T., and Sigvaldasot∼ G. E. (1974) Geochim. Cosmochim. Acta., 38, 577-88Google Scholar
Nakamura, N. (1974) Ibid. 38, 757-75.Google Scholar
Norry, M.J. and Fitton, J.G. (1983) In Continental Basalts and Mantle Xenoliths (C. J. Hawkesworth and M. J. Norry, eds.) Shiva Publishing, 5-19.Google Scholar
Oskarsson, N., Sigvaldason, G.E., and Steinthorsson, S. (1982) J. Petrol., 23, 28-74Google Scholar
Oskarsson, N., Sigvaldason, G.E., and Steinthorsson, S.(1985) J. Geophys. Res., 90, 1001-125Google Scholar
Pearce, J.A. (1982) In Andesites (R. S. Thorpe, ed.) John Wiley and Sons, 525–48.Google Scholar
Schock, H.H. (1979) Chem. Geol., 26, 119-33Google Scholar
Shaw, H.R. (1974) In Geochemical Transport and Kinetics. Carnegie Inst. Wash. 139-70.Google Scholar
Sheppard, S.M. F. (1977) In Volcanic Processes in Ore Genesis. Inst. Mining Metallurgy and Geol. Lond. 25-41.Google Scholar
Sheppard, S.M. F.and Harris, C. (1985) Contrib. Mineral. Petrol., 91, 74-81Google Scholar
Sigurdsson, H. (1970) Ph.D. thesis, University of Durham. and Sparks, R.S. J. (1978) Bull. Volcan., 41, 149-67.Google Scholar
Sigurdsson, H. (1981) J. Petrol., 22, 41-84.Google Scholar
Sigvaldason, G.E. (1974) Ibid. 15, 497-524.Google Scholar
Sigvaldason, G.E. (1979) Nordic Volcanol. Inst. Report 03, Reykjavik.Google Scholar
Smith, R.L. (1979) Geol. Soc. Am. Spec. Pap. 180, 5-27.Google Scholar
Sparks, R.S. J., Sigurdsson, H., and Wilson, L. (1977) Nature 267, 315-8.Google Scholar
Sparks, R.S. J., Sigurdsson, H., and Wilson, L. Wilson, L., and Sigurdsson, H. (1981) Phil. Trans. R. Soc. Lond., A299, 241-73.Google Scholar
Sun, S-S. and Hanson, G.N. (1976) Contrib. Mineral. Petrol., 54, 139-55.Google Scholar
Taylor, H.P., Jr. (1968) Ibid. 19, 1-71.Google Scholar
Taylor, H.P., Jr. and Epstein, S. (1962) Bull. Geol. Soc. Am. 73, 461–80.Google Scholar
Taylor, H.P., Jr. and Epstein, S. and Forester, R.W. (1971) J. Petrol., 12, 465-97.Google Scholar
Thirlwall, M.F. and Jones, N.W. (1983) Continental Basalts and Mantle Xenoliths (C. J. Hawkesworth and M. J. Norry, eds.) Shiva Publishing, 186-208.Google Scholar
Thompson, R.N. (1982) Scott. J. Geol., 18, 49-107.Google Scholar
Thompson, R.N. Dickin, A.P., Gibson, I.L., and Morrison, M.A. (1982) Contrib. Mineral. Petrol., 79, 159-68Google Scholar
Watson, E.B. (1982) Ibid. 80, 73-87.Google Scholar
Watson, E.B. and Jurewicz, S.R. (1984) J. Geol., 92, 121-31.Google Scholar
Wood, D.A. (1978) J. Petrol., 19, 393-436Google Scholar
Wood, D.A. Joron, J-L., Treuil, M., Norry, M., and Tarney, J. (1979) Contrib. Mineral. Petrol., 70, 319-39Google Scholar
Zindler, A., Jagoutz, E., and Goldstein, A. (1982) Nature,, 298, 519-23.Google Scholar
Zindler, A., Jagoutz, E., and Goldstein, A. Staudigel, H., and Batiza, R. (1984) Earth Planet. Sci. Lett., 70, 175-95.Google Scholar