Experimental Insights into Crystallization of Hydrous Basaltic Andesite

University Of Hawaii, Honolulu

Investigators

Abstract

The textures and phase compositions in volcanic rocks preserve information about the processes that expel them. The proportions, compositions, and interrelationships of crystalline phases and glasses potentially reveal pre-eruptive intensive conditions, the timing of changes therein, and the devolatilization history coeval with eruptive ascent. These parameters are recognized as important monitoring tools at active volcanoes, as well as for interpreting geologic events at pre-historic and remote eruptions. This proposal presents plans to (1) investigate crystallization kinetics, melt inclusion entrapment, and isotopic fractionation in hydrous magma of mafic-intermediate composition using dynamic cooling and decompression experiments, and (2) adapt an existing professional development program for K-12 science teachers to provide Hawaii's pre-service and seasoned teachers with skills and training needed to implement student field trips to sites on Oahu, Hawaii, and Maui islands. This project will investigate crystallization kinetics and melt inclusion entrapment in hydrous magma of mafic-intermediate composition using dynamic cooling and decompression experiments. These experiments involve a complex but volcanologically plausible sequence of events for which no prior experimental constraints are available. The study will redress significant gaps in knowledge of crystallization of natural magmas by examining crystallization kinetics in volatile-rich basaltic andesite, and the experimental design will facilitate comparison with theories of nucleation and phase transformation.