Award Date

5-1-2021

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

First Committee Member

Shichun Huang

Second Committee Member

Arya Udry

Third Committee Member

Michael Wells

Fourth Committee Member

William Ramsey

Number of Pages

56

Abstract

At many oceanic volcanoes, such as Hawaii, mantle-derived magmas migrate to crustal level magma chambers, where they accumulate before eruption. Understanding the magma chamber residence times, or the time gaps between the arrivals of new magmas and eruptions, is important in volcanic hazard mitigation. Here I apply iron and magnesium isotope effects in olivines to constrain these times at Hawaiian volcanoes. Combined with published data, I present bulk ?56Fe (-1.706 to 0.489) and ?26Mg (-0.400 to 0.356) in 108 Hawaiian olivines erupted from the pre-shield, shield, and post-shield stages. The Hawaiian olivine ?56Fe and ?26Mg represent the largest Fe-Mg isotope variations ever observed in natural olivines, and show a remarkably linear, negative correlation that can only be created through chemical diffusion. I use a Monte Carlo technique to constrain the magma chamber residence times to be on the weekly to annual timescales at pre-shield and shield stages. The times for post-shield olivines, due to a decrease in magma production during this stage, are on the annual to decadal timescales.

Keywords

Chronicling magma; Crystal; Hawaiian volcanoes; Isotope

Disciplines

Geochemistry

File Format

pdf

File Size

2100 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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