Magma Fractionation Processes and Timescales: Fogo, Furnas and Fuji Volcanoes

Miami University, Oxford OH

Investigators

Abstract

Magma Fractionation Processes and Timescales: Fogo, Furnas and Fuji Volcanoes EAR- 0207529 PI: Widom This project is a combined volcanological, geochemical, isotopic and geochronologic study of recent, highly evolved and chemically zoned eruptive products of Fogo and Furnas volcanoes in the Azores (Portugal), and Fuji volcano in Japan. The project will involve petrographic and microprobe analysis, major and trace element and Sr-Nd-Pb isotope analysis, and U-series disequilibria studies of whole rock pumices and mineral and glass separates, as well as high precision Ar-Ar dating of feldspar separates. Specific questions that will be addressed include the role of open vs. closed system processes during magmatic differentiation, the timescales over which magma differentiation and chemical zonation occur, and the relationship between magma residence timescales and eruptive volumes. The combined studies of eruptions from the Azores and Fuji will allow comparisons of the processes and timescales operating in magmatic systems in distinct tectonic settings (intraplate vs. subduction zone), and in magmatic systems that are compositionally distinct (alkaline vs. calc-alkaline).