Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-23T22:35:19.967Z Has data issue: false hasContentIssue false

CO2 fluid inclusions in ultramafic xenoliths from the Iblean Plateau, Sicily, Italy

Published online by Cambridge University Press:  05 July 2018

B. De Vivo
Affiliation:
Dipartimento di Geofisica e Vulcanologia, Largo S. Marcellino 10, 80138 Napoli, Italy
A. Lima
Affiliation:
Dipartimento di Geofisica e Vulcanologia, Largo S. Marcellino 10, 80138 Napoli, Italy
V. Scribano
Affiliation:
Istituto di Scienze della Terra, Corso Italia 55, 95129 Catania, Italy

Abstract

The Iblean Plateau (Southeastern Sicily, Italy) consists of a thick Meso-Cenozoic carbonate sequence with interbedded volcanic horizons (alkaline and tholeiitic basalts). The alkaline basalts contain ultramafic (peridotites and pyroxenites) and mafic xenoliths. The peridotites are spinel-bearing lherzolites and lherzolitic harzburgites, with porphyroblastic to protogranular texture. Pyroxenites consist of Cr-diopside-bearing and Al-augite-bearing websterites. The mineral chemistry of the nodules indicates temperatures between 700 and 1050°C.

Fluid inclusions containing CO2 and (sometimes) various proportions of silicate glass have been studied in olivine, orthopyroxene and clinopyroxene. The secondary inclusions occur as trails of CO2-rich inclusions, often cross-cutting deformation lamellae. The few primary inclusions, generally empty, show clear evidence of decrepitation. Of the 390 inclusions examined, 97% homogenized to the liquid phase (Th → L = −43.9 to +30.9°C); 3% homogenized to the vapour phase (Th → V = + 20.5 to +30.3°C, yelding CO2 densities in the range 0.20–1.13 g/cm3. Assuming a trapping temperature of 1100°C, the corresponding trapping pressure for a pure CO2 system lies in the range 0.6–11.0 kbar, i.e. a depth of ∼2.2 to 42 km.

The majority of CO2 trapping events in the xenoliths occurred from 2.2 to 11.0 kbar, with no major trapping events at pressures less than 2.3 kbar, indicating the absence of a shallow magma reservoir below the Iblean Plateau.

Type
Magmatic/metamorphic environment
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1990

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

Andersen, T., O'geilly, S. Y. and Griffihn, W. L. (1984) The trapped fluid phases in upper mantle xenoliths from Victoria, Australia: implications for mantle metasomatism. Contrib. Mineral. Petrol. 88, 72-85.CrossRefGoogle Scholar
Andersen, T., Griffin, W. L. and O'Reilly, S. Y. (1987) Primary sulphide melt inclusions in mantle-derived megacrysts and pyroxenites. Lithos 20, 279-94.Google Scholar
Belkin, H. E. and De Vivo, B. (1989) Glass, phlogopite, and apatite in spinel peridotite xenoliths from Sardinia (Italy): evidence for mantle metasomatism. IACVEI Meeting, Santa Fe, NM, June 26-July 1, Program with Abstracts, p. 20.Google Scholar
Belkin, H. E. and De Vivo, B., Roedder, E. and Cortini, M. (1985) Fluid inclusion geobarometry from ejected Mt Somma- Vesuvius nodules. Am. Mineral. 70, 288-303.Google Scholar
Bilal, A. and Touret, J. (1976) Fluid inclusions in catazonal xenoliths from Bournac (Massif Central, France). Bull. Mineral. 99, 134-9.Google Scholar
Burke, E. A. J. and Lustenhouwer, W. J. (1987) The application of a multichannel laser Raman microprobe (Microdil-28) to the analysis of fluid inclusions. Chem. Geol. 61, 11-17.CrossRefGoogle Scholar
Cunningham, C. G. and Corollo, C. (1980) Modification of a fluid inclusion heating freezing stage. Econ. Geol. 75, 335-7.CrossRefGoogle Scholar
Dawson, J. B. (1984) Contrasting types of upper mantle metasomatism? In: Kimberlites v. II: The mantle and crust-mantle relationships, Proc. of the ‘Third Int'l Kimberlite Conference’ (Kornprobst, J., ed.) Elsevier, Amsterdam, pp. 289294.CrossRefGoogle Scholar
De Vivo, B., Frezzotti, M. L., Lima, A. and Trigila, R. (1988) Spinel lherzolite nodules from Oahu island (Hawaii): a fluid inclusion study. Bull. Mineral. 111, 307-19.Google Scholar
Dromgoole, E. L. and Pasteris, J. D. (1985) Interpretation of the sulfide assemblages in a suite of xenoliths from Kilbourne Hole, New Mexico. Geol. Soc. Am., Abstract with Programs. 17, 157.Google Scholar
Fabries, J. (1979) Spinel-olivine geothermometry in peridotite from ultramafic complexes. Contrib. Mineral. Petrol. 69, 329-36.CrossRefGoogle Scholar
Francis, D., Javoy, M., Nadeau, S. and Pineau, F. (1986) Upper mantle xenoliths along the north western margin of North America: Fluid inclusions and C and H isotopes. Terra Cognita 6, 191-2.Google Scholar
Gasparik, T. (1984) Two-pyroxene thermobarometry with new experimental data in the system CaO-MgO-Al2O3-SiO2 . Contrib. Mineral. Petrol. 87, 73-87.CrossRefGoogle Scholar
Gasparik, T. (1987) Orthopyroxene thermobarometry in simple and complex systems. Ibid. 96, 357-70.Google Scholar
Griffin, W. L., Wass, S. Y. and Hollis, J. D. (1984) Ultramafic xenoliths from Bullenmerri and Gnotuk Maars, Victoria, Australia: Petrology of a subcontinental crust-mantle transition. J. Petrol. 25, 53-87.CrossRefGoogle Scholar
Harte, B. (1977) Rock nomenclature with particular relation to deformation and recrystallization textures in olivine-bearing xenoliths. J. Geol. 85, 279-88.CrossRefGoogle Scholar
Kennedy, G. C. (1954) Pressure-volume relations in CO2 at elevated temperatures and pressures. Am. J. Sci. 252, 225-41.CrossRefGoogle Scholar
Kerrick, D. M. and Jacobs, G. K. (1981) A modified Redlich-Kwong equation for H2O, CO2 and H2O-CO2 mixtures at elevated pressures and temperatures. Ibid. 281, 735-67.Google Scholar
Lentini, F., Grasso, M. and Carbone, S. (1987) Introduzione alia geologia della Sicilia e guida all'escursione. Università degli Studi di Catania, Istituto di Scienze della Terra. Catania, 60 pp.Google Scholar
Lindsley, D. H. (1983) Pyroxene thermometry. Am. Mineral. 68, 477-93.Google Scholar
Mercier, J. C. and Nicolas, A. (1975) Textures and fabrics of upper-mantle peridotites as illustrated by xenoliths from basalts. J. Petrol. 16, 454-87.CrossRefGoogle Scholar
Nixon, P. H. (1987) Mantle xenoliths. Wiley J. & Sons, London, 563 pp.Google Scholar
O'Reilly, S. Y. and Griffin, W. L. (1985) The nature and role of fluids in the upper mantle: evidence in xenoliths from Victoria, Australia. Abstracts of Conf. on Stable Isotopes and Fluid Processes in Mineralization, Queensland, 10-12 July, p. 58-59.Google Scholar
Pasteris, J. D. (1987) Fluid inclusions in mantle xenoliths. In Mantle Xenoliths (Nixon, P. H., ed.) John Wiley & Sons, London, 691707.Google Scholar
Poty, B., Leroy, J. and Jachimowicz, L. (1976) Un nouvel appareil pour la mesure des temperatures sous le microscope: l'installation de microthermometrie de Chaix Meca. Bull. Mineral. 99, 182-6.Google Scholar
Roedder, E. (1981) Origin of fluid inclusions and changes that occur after trapping. In Fluid inclusions: application to petrology (Hollister, L. S. and Crawford, M. L., eds.) Mineral. Assoc. Canada Short Course, Calgary. 6, 101-37.Google Scholar
Roedder, E. (1983) Geobarometry of ultramafic xenoliths from Loihi seamount, Hawaii, on the basis of CO inclusions in olivine. Earth Planet. Sci. Lett. 66, 369-79.CrossRefGoogle Scholar
Roedder, E. (1984) Fluid inclusions. Review in Mineralogy, Min. Soc. Am., 12, 70-1.Google Scholar
Sachtleben, T. and Seck, H. A. (1981) Chemical control of Al-solubility in orthopyroxene and its implications on pyroxene geothermometry. Contrib. Mineral. Petrol. 78, 157-65.CrossRefGoogle Scholar
Scribano, V. (1986) The harzburgite xenoliths in a Quaternary basanitoid near Scordia (Hyblean Plateau, Sicily). Rend. Soc. Ital. Mineral. Petrol. 41, 245-55.Google Scholar
Scribano, V. (1987a) The ultramafic and mafic nodule suite in a tuff-breccia pipe from Cozzo Molino (Hyblean Plateau, SE Sicily). Ibid. 42, 203-17.Google Scholar
Scribano, V. (1987b) Deep-seated xenoliths in alkaline volcanic rocks from the Hyblean Plateau (SE Sicily). Mere. Soc. Geol. ltal. 38, in press.Google Scholar
Scribano, V. (1987c) Origin of websterite nodules from some alkaline volcanic rocks of Hyblean Plateau (South Eastern Sicily). Period. Mineral. 56, in press.Google Scholar
Shmonov, V. M. and Shmulovich, K. I. (1974) Molal volumes and equation of state of CO2 at temperatures from 100 to 1000°C and pressures from 2000 to 10 000 bars. Dokl. Akad. Nauk SSSR 217, 935-8.Google Scholar
Solovova, I. P., Kovalenko, V. I., Naumov, V. B., Ryabchikov, I. D., Ionov, D. A. and Tsepin, A. I. (1985) Carbon dioxide-sulfide-silicate inclusions in clinopyroxenes from mantle xenoliths. Ibid. 285, 199-202.Google Scholar
Sparks, R. S. J., Pinkerton, H. and Macdonald, R. (1977) The transport of xenoliths in magmas. Earth Planet. Sci. Lett. 35, 234-8.CrossRefGoogle Scholar
Spera, F. J. (1984) Carbon dioxide in petrogenesis III: role of volatiles in the ascent of alkaline magma with special reference to xenolith-bearing mafic lavas. Contrib. Mineral. Petrol. 88, 217-32.CrossRefGoogle Scholar
Van Den Kerkhof, A. M. (1988) The system CO2-CH4-N2 in fluid inclusions.” theoretical modelling and geological applications. PhD thesis, Vrije Universiteit Amsterdam, 206 pp.Google Scholar
Wood, B. J. and Holloway, J. R. (1984) Thermodynamic model for subsolidus equilibria in the system CaO-Al2O3-SiO2 . Geochim. Cosmochim. Acta, 48, 159-76.CrossRefGoogle Scholar