Magmatic processes that generated the rim andesites of Medicine Lake Volcano, N. California
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1028979739-MIT.pdf
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Author(s)
Fuentes, Jocelyn J
Advisor(s)
Timothy Grove.
Date Issued
2012
Publisher
Massachusetts Institute of Technology
Abstract
This paper characterizes the compositionally distinctive high-Na andesite lavas at Medicine Lake Volcano that erupted at ~100 ka and that built most of Medicine Lake's caldera. These high-Na lavas define a compositional trend that formed by fractional crystallization in a shallow magma chamber (~ 4 to 8 km). Petrologic evidence indicates pre-eruptive H20 contents of 2 to 4 wt.% H20 over a temperature range of 1070 to 900 C. Oxygen fugacity recorded in coexisting spinel and rhombohedral oxides varies from NNO (Nickel - Nickel Oxide) to NNO 0.7 log units. Experiments performed at 1 kbar - H20 saturated conditions at the NNO buffer on a primitive andesite reproduce most of the major element compositional variability exhibited in the high-Na lavas.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages [32]-[34]).
Subjects
Earth, Atmospheric, and Planetary Sciences.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.
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