HR: 1340h
AN: V43E-1451    [Abstracts]
TI: Geochemical investigation of magma evolution in Campi Flegrei volcanic field (Italy) based on melt inclusions
AU: * Cannatelli, C
EM: geomail3@vt.edu
AF: Universita' degli Studi di Napoli "Federico II", Dipartimento di Geofisica e Vulcanologia, Via Mezzocannone 8, Napoli, 80134 Italy
AU: Bodnar, R J
AF: Virginia Polytechnic Institute and State University, Dept.of Geosciences, Fluids Res. Lab., 4044 Derring Hall, Blacksburg, VA 24061 United States
AU: De Vivo, B
AF: Universita' degli Studi di Napoli "Federico II", Dipartimento di Geofisica e Vulcanologia, Via Mezzocannone 8, Napoli, 80134 Italy
AU: Fedele, L
AF: Universita' degli Studi di Napoli "Federico II", Dipartimento di Geofisica e Vulcanologia, Via Mezzocannone 8, Napoli, 80134 Italy
AU: Lima, A
AF: Universita' degli Studi di Napoli "Federico II", Dipartimento di Geofisica e Vulcanologia, Via Mezzocannone 8, Napoli, 80134 Italy
AU: Piochi, M
AF: Osservatorio Vesuviano, Via Diocleziano 328, Napoli, 80124 Italy
AB: Melt inclusions are a powerful tool for understanding the evolutionary history (crystallization, volatile evolution, mixing, etc.) of magmas. They are also useful to interpret the conditions of primary melt generation and extraction. In particular the volatile content in magmas (e.g. H$_{2}$O, CO$_{2}$) is of critical importance in determining the eruptive style and magma evolution, because degassing is usually one of the major phenomena before and during an eruption. In populated and active volcanic areas such as Campi Flegrei (Italy), understanding the role of volatile content in magmas is a necessary requirement to assess volcanic risks. The goal of our project is to define the geochemical parameters that control the internal dynamics of magmatic systems of this active volcanic area. The eruptive products of Campi Flegrei were selected for study based on age, eruptive characteristic, mineralogy, chemical compositions and structural position of eruptive centers, in order to verify the existence of a possible change in plumbing systems between different eruptions. Here we report preliminary data on latitic-to-trachytic products from Fondo Riccio eruption. Compositions of the inclusions and host phenocryst were obtained by electron microprobe techniques. The compositions of melt inclusions in pyroxenes vary from trachybasalt to trachite, in those Mg-rich diopside are less evolved ( ranging from trachybasalt to shoshonite) than in Fe-rich diopside (from latite to trachyte). The compositions of inclusions in Fo 85-87 olivine are similar to those in Mg-rich pyroxenes. Homogenization temperatures were obtained by microthermometric experiments and range from 950 to $1000\deg$C for feldspars, from 1030 to $1080\deg$C for pyroxenes and from 1070 to $1120\deg$C for olivines. Volatile contents of melt inclusions, based on electron microprobe analyses, are $<$ 2 wt %. The chemical composition of minerals and melt inclusions, as well thermometric data, are consistent with a continuos crystallization process of an evolving magma body.
DE: 1000 GEOCHEMISTRY (New field, replaces Rock Chemistry)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting