Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-25T19:38:02.554Z Has data issue: false hasContentIssue false
  • English
  • Français

Glass-bearing felsic nodules from the crystallizing sidewalls of the 1944 Vesuvius magma chamber

Published online by Cambridge University Press:  05 July 2018

P. Fulignati ,
P. Marianelli  and
A. Sbrana
P. Marianelli*
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria, 53-56126, Pisa, Italy
A. Sbrana
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria, 53-56126, Pisa, Italy
*
* E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

In the 1944 Vesuvius eruption, the shallow magma chamber was disrupted during the highly energetic explosive phases. Abundant cognate xenoliths such as subvolcanic fergusites and cumulates, hornfels, skarns and rare marbles occur in tephra deposits.

Mineral chemistry, melt inclusions in minerals and glassy matrix compositions show that fergusites (highly crystalline rocks made of leucite, clinopyroxene, plagioclase, olivine, apatite, oxides and glass) do not correspond to melt compositions but result from combined sidewall accumulation of crystals, formed from K-tephriphonolitic magma resident in the chamber, and in situ crystallization of the intercumulus melt. Very low H2O contents in the intercumulus glass are revealed by FTIR and apatite composition. Whole rock compositions are essentially determined by the bulk mineral assemblages.

Glass–bearing fergusites constitute the outer shell of the magma chamber consisting of a highly viscous crystal mush with a melt content in the range 20–50 wt.%. The leucite/(clinopyroxene+olivine) modal ratio, varies with the extraction order of magmas from the chamber, decreasing upwards in the stratigraphic sequence. This reflects a vertical mineralogical zonation of the crystal mush. These data contribute to the interpretation of the subvolcanic low–pressure crystallization processes at the magma chamber sidewalls affecting alkaline potassic magmas.

Keywords

glass–bearing fergusitesmagma chamberrigid crustVesuvius1944 eruption
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 3 , June 2000 , pp. 481 - 496
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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

Bacon, C.R. (1989) Crystallization of accessory phases in magmas by local saturation adjacent to phenocrysts. Geochim. Cosmochim. Acta, 53, 1055–66.CrossRefGoogle Scholar
Belkin, H.E., De Vivo, B., Roedder, E. and Cortini, M. (1985) Fluid inclusion geobarometry from ejected Mt. Somma-Vesuvius nodules. Amer. Mineral., 70, 288–303.Google Scholar
Candela, P.A. (1986) Toward a thermodynamic model for the halogens in the magmatic systems: an application to melt-vapour-apatite equilibria. Chem. Geol., 57, 289–301.CrossRefGoogle Scholar
Cioni, R., Marianelli, P. and Santacroce, R. (1999) Temperature of Vesuvius magmas. Geology, 27, 443–6.2.3.CO;2>CrossRefGoogle Scholar
Cortini, M., Lima, A.M. and DeVivo, B. (1985) Trapping temperatures of melt inclusions from ejected Vesuvian mafic xenoliths. J. Volcanol. Geotherm. Res., 26, 167–72.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A. and Zussman, J. (1966) An Introduction to the Rock-Forming Minerals. Longmans, London.Google Scholar
Fulignati, P., Marianelli, P. and Sbrana, A. (1998) New insights on the thermometamorphic-metasomatic magma chamber shell of the 1944 eruption of Vesuvius. Acta Vulcanol., 10, 47–54.Google Scholar
Grove, T.L. and Bryan, W.B. (1983) Fractionation of pyroxene-phyric MORB at low pressure: an experimental study. Contrib. Mineral. Petrol., 84, 293–309.CrossRefGoogle Scholar
Haggerty, S.E. (1991) Oxide mineralogy of the upper mantle. Pp. 355–416 in: Oxide Minerals: Petrologic and Magnetic Signifricance (Lindsley, D.H., editor). Reviews in Mineralogy, 25, Mineralogical Society of America, Washington D.C.CrossRefGoogle Scholar
Hermes, O.D. and Cornell, W.C. (1981) Quenced crystal mush and associate d magma comositions as indicated by intercumulus glasses from Mt. Vesuvius, Italy. J. Volcanol. Geotherm. Res., 9, 133–49.CrossRefGoogle Scholar
Imbò, G. (1949) L'attività eruttiva vesuviana e le relative osservazioni nel corso dell’intervallo eruttivo 1906-1944 ed in particolare del parossismo del 18 Marzo 1944. Ann. Oss. Vesuviano, V serie, 185-380 (in Italian).Google Scholar
Irvine, T.N. (1982) Terminology for layered intrusions. J. Petrol., 23, 127–62.CrossRefGoogle Scholar
IUGS, International Union of Geological Sciences, Subcommission on the Systematics of Igneous Rocks (1973) Plutonic rocks, classification and nomenclature. Geotimes, 18, 26–30.Google Scholar
Kamenetsky, V., Metrich, N. and Cioni, R. (1995) Potassic primary melts of Vulsini (Roman Province): evidence from mineralogy and melt inclusions. Contrib. Mineral. Petrol., 120, 186–96.CrossRefGoogle Scholar
Marianelli, P., Metrich, N. and Sbrana, A. (1999) Shallow and deep reservoirs involved in the magma supply of the 1944 eruption of Vesuvius. Bull. Volcanol., 61, 48–63.CrossRefGoogle Scholar
Marsh, B.D. (1989) Magma chambers. Ann. Rev. Earth Planet. Sci., 17, 439–74.CrossRefGoogle Scholar
Middlemost, E.A.K. (1989) Iron oxidation ratios, norms and the classification of volcanic rocks. Chem. Geol., 77, 19–26.CrossRefGoogle Scholar
Nielsen, R.L., Michael, P.J. and Sours-Page, R. (1998) Chemical and physical indicators of compromised melt inclusions. Geochim. Cosmochim. Acta, 62, 831–9.CrossRefGoogle Scholar
Parascandola, A. (1945) L'eruzione vesuviana del Marzo 1944. 1.- I prodotti piroclastici. Rend. Acc. Sci. Fis. Mat. Napoli, 13, 285–305 (in Italian).Google Scholar
Roeder, P.L. and Emslie, R.F. (1970) Olivine-liquid equilibrium. Contrib. Mineral. Petrol., 29, 275–89.CrossRefGoogle Scholar
Scherillo, A. (1949) Le lave e le scorie dell'eruzione vesuviana del marzo 1944. Ann. Oss. Vesuviano V serie, 169–83 (in Italian).Google Scholar
Stormer, J.Cr. Jr (1983) The effect of recalculation on estimates of temperature and oxygen fugacity from analyses of multicomponent iron-titanium oxides. Amer. Mineral., 68, 586–94.Google Scholar
Stormer, J.Cr. Jr and Nicholls, J. (1978) XLFRAC: a program for the interactive testing of magmatic differentiation models. Computers and Geoscience, 4, 143–59.CrossRefGoogle Scholar
Tait, S.R. (1988) Samples from the crystallizing boundary layer of a zoned magma chamber. Contrib. Mineral. Petrol., 100, 470–83.CrossRefGoogle Scholar
Tait, S.R., Worner, G., Van Den Bogaard, P. and Schminke, H-U. (1989) Cumulate nodules as evidence for convective fractionation in a phonolite magma chamber. J. Volcanol. Geotherm. Res., 37, 21–37.CrossRefGoogle Scholar
Webster, J.D. and Holloway, J.R. (1990) Partitioning of F and Cl between magmatic hydrothermal fluids and highly evolved granitic magmas. Geol. Soc. Amer. Special Paper, 246, 21–34.CrossRefGoogle Scholar
Wholetz, K. (1996) Magma (An estimation of magma physical and chemical properties with IUGG classification). University of California, Los Alamos National Laboratories.Google Scholar
Yardley, B.W.D. (1985) Apatite composition and the fugacities of HF and HCl in metamorphic fl uids. Mineral. Mag., 49, 77–9.CrossRefGoogle Scholar