Title

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

Presenter Information

Michelle Harris

Document Type

Oral Presentation

Location

SURC Ballroom A

Start Date

17-5-2012

End Date

17-5-2012

Abstract

Documenting the physiochemical processes that influence magma composition is critical for predicting eruption styles and managing volcanic hazards. Silica-rich eruptions tend to be more explosive and hazardous, whereas magnesium-rich eruptions tend to be more effusive. Previous studies have documented how magma composition changes from magnesium-rich to silica-rich in subduction zone volcanoes, but controversy remains regarding the effects different magmatic processes have on eruption styles. A combination of three magmatic processes dominates chemical changes within magmas: Recharge, Assimilation, and Fractional Crystallization. Recharge is the injection of new, hotter magma into existing magma and may trigger volcanic eruptions. Assimilation is the mixing between magma and melt from surrounding rock and results in a more silicic, explosive magma. Fractional Crystallization occurs within all magmas and is the process of formation and segregation of solid minerals from liquid melt. Volcanic rocks from Filicudi Island, Italy, span a compositional range from low-silica, high-magnesium to higher-silica, lower-magnesium, which cannot be related by a single process. My MS research examines compositional data, both elemental and isotopic, collected at a small spatial scale from the core-to-rim of plagioclase (a silica, calcium and sodium-rich mineral stable within magma from low-silica basalt to high silica andesite). Results will provide insight into the processes that caused compositional diversity and contributed to explosive volcanism on Filicudi Island. Although Filicudi volcano is no longer active, results can be applied to active subduction zone volcanoes and will improve understanding of processes that catalyze volcanic eruptions.

Poster Number

1

Faculty Mentor(s)

Wendy Bohrson, Chris Mattinson

Additional Mentoring Department

Geological Sciences

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May 17th, 2:00 PM May 17th, 4:30 PM

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

SURC Ballroom A

Documenting the physiochemical processes that influence magma composition is critical for predicting eruption styles and managing volcanic hazards. Silica-rich eruptions tend to be more explosive and hazardous, whereas magnesium-rich eruptions tend to be more effusive. Previous studies have documented how magma composition changes from magnesium-rich to silica-rich in subduction zone volcanoes, but controversy remains regarding the effects different magmatic processes have on eruption styles. A combination of three magmatic processes dominates chemical changes within magmas: Recharge, Assimilation, and Fractional Crystallization. Recharge is the injection of new, hotter magma into existing magma and may trigger volcanic eruptions. Assimilation is the mixing between magma and melt from surrounding rock and results in a more silicic, explosive magma. Fractional Crystallization occurs within all magmas and is the process of formation and segregation of solid minerals from liquid melt. Volcanic rocks from Filicudi Island, Italy, span a compositional range from low-silica, high-magnesium to higher-silica, lower-magnesium, which cannot be related by a single process. My MS research examines compositional data, both elemental and isotopic, collected at a small spatial scale from the core-to-rim of plagioclase (a silica, calcium and sodium-rich mineral stable within magma from low-silica basalt to high silica andesite). Results will provide insight into the processes that caused compositional diversity and contributed to explosive volcanism on Filicudi Island. Although Filicudi volcano is no longer active, results can be applied to active subduction zone volcanoes and will improve understanding of processes that catalyze volcanic eruptions.