Chemical and isotopic zoning in plagioclase phenocrysts has proved to be a powerful tool to decipher petrogenesis in ‘open’ volcanic (Davidson and Tepley, 1997) and plutonic (Gagnevin et al., 2005) systems. While single-grain isotopic variations constrain the nature of the melt involved in magma mixing, the promising aspect of using trace elements in plagioclase is their sensitivity to intensive parameters (P, T, XH2O) during growth. Capraia Volcano (7.2–7.6 Ma) belongs to the Tuscan Magmatic Province. Most lavas are andesitic and dacitic in composition, with a predominant high-K calc-alkaline signature. Dacites that display the best evidence of plagioclase zoning were selected for this study. The aim was to correlate the zoning patterns to elucidate the evolution of the Capraia magma chamber. Phenocrysts display complex textures (see accumulated BSE image below) consisting of growth zones separated by resorption surfaces, suggesting repeated disequilibrium conditions during crystallisation.
Insights into magma evolution in Capraia Volcano (Italy) from plagioclase chemical and isotopic zonation / D. GAGNEVIN; J.S. DALY; T.E. WAIGHT; G.E. POLI; S. CONTICELLI. - In: GEOCHIMICA ET COSMOCHIMICA ACTA. - ISSN 0016-7037. - STAMPA. - 70:(2006), pp. 188-188. (Intervento presentato al convegno 16th Annual V.M. Goldschmidt Conference 2006 tenutosi a Merlbourne nel August 2006) [10.1016/j.gca.2006.06.380].
Insights into magma evolution in Capraia Volcano (Italy) from plagioclase chemical and isotopic zonation
CONTICELLI, SANDRO
2006
Abstract
Chemical and isotopic zoning in plagioclase phenocrysts has proved to be a powerful tool to decipher petrogenesis in ‘open’ volcanic (Davidson and Tepley, 1997) and plutonic (Gagnevin et al., 2005) systems. While single-grain isotopic variations constrain the nature of the melt involved in magma mixing, the promising aspect of using trace elements in plagioclase is their sensitivity to intensive parameters (P, T, XH2O) during growth. Capraia Volcano (7.2–7.6 Ma) belongs to the Tuscan Magmatic Province. Most lavas are andesitic and dacitic in composition, with a predominant high-K calc-alkaline signature. Dacites that display the best evidence of plagioclase zoning were selected for this study. The aim was to correlate the zoning patterns to elucidate the evolution of the Capraia magma chamber. Phenocrysts display complex textures (see accumulated BSE image below) consisting of growth zones separated by resorption surfaces, suggesting repeated disequilibrium conditions during crystallisation.
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