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Degree

Master of Science, Miami University, Geology, 2007.

Abstract

Furnas volcano, an active stratovolcano on the island of São Miguel, Azores, is considered one of Europe’s most hazardous volcanoes. This work constitutes the first detailed petrographic, compositional, and isotopic study of the Furnas 1630 AD eruptive deposit. The eruptive products of the Furnas 1630 AD deposit are almost exclusively trachytic, with limited major element variations but large trace element variations that can be attributed to extensive fractional crystallization. Constant Nd and Pb but variable Sr isotopic signatures in the 1630 AD eruptive products, including whole rock, glass and individual sanidine crystals, suggest that fractionation was accompanied by assimilation of seawater altered syenite from the magma chamber walls. Analysis of stratigraphically controlled samples from throughout the Furnas 1630 AD deposit indicate systematic but non-monotonic variations in the composition of the eruptive products that reflect complex magma chamber geometry and/or multiple magma chambers.

Keywords

Azores; trachytic pumices; fractional crystallization; open-system processes; zoned magma chambers

Advisor

Elisabeth Widom

Pages

36p.

Document number: miami1186143145
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=miami1186143145

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