Documenting Magmatic Processes at Filicudi Island, Aeolian Arc, Italy: Integrating Quantitative Modeling and Plagioclase Textural and In Situ Compositional Data

Michelle Harris
July 2012

Abstract

Documenting the physiochemical processes that influence magma composition is critical for forecasting eruption styles and managing volcanic hazards. Compositional diversity of magmas develops through recharge, assimilation, and fractional crystallization (RAFC) within subvolcanic magma reservoirs. Integration of MELTS modeling, whole rock, plagioclase textural and in situ elemental and isotopic data from Filicudi Island, Italy allow documentation of the roles and relative chronology that RAFC played in the magmatic evolution and elucidates aspects of the magma plumbing system structure.

Results indicate a polybaric magma plumbing system with deeper (3.5-4 kilobars) and shallower (0.5-1.2 kilobars) storage regions. Within the deeper system, FC acted to differentiate magma, while water contents acted to suppress plagioclase growth. Differentiated magma intruded to shallower levels, where plagioclase crystallized rapidly resulting in monotonous textures and high anorthite contents. Within the shallower system, recharge from the deeper system and continued FC contributed to the compositional diversity observed on Filicudi Island.

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