Geochronological, Isotopic and Petrological Constraints on Magma Dynamics at Mt. Etna

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9614381 Spera This project will focus on constraining aspects of the magma geneses processes at one of the most active volcanoes in the world, Mt. Etna. Specifically, the study will concentrate on investigating correlations between alkali enrichments and dramatic changes in Sr and Pb isotopic composition. To assess whether these isotopic changes are more reasonably interpreted as the result of crustal contamination or mantle heterogeneity, samples from six historical flows will be studied with a combination of crystal size distribution analysis (CSD) and microsampling of phenocrysts and microphenocrysts. This technique will allow the documentation of how the isotopic composition of the materials change with crystal size. Common isotopic signatures are expected for phenocrysts and matrix if the variations in the chemistry of the magmas is the result of heterogeneity in the source. Alternatively, changes in isotopic composition associated with different crystal size distribution of phenocrysts would imply the importance of crustal contamination as a petrogenetic process.