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Date of Award

Summer 2025

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

DeBari, Susan M., 1962-

Second Advisor

Caplan-Auerbach, Jacqueline

Third Advisor

Druitt, Timothy H.

Abstract

Crystals and glass produced in explosive volcanic eruptions provide insights into magmatic processes. Kolumbo, a shallow submarine volcano located in the Hellenic Arc, last erupted in 1650 CE in a violently explosive and tsunamigenic event. Understanding the magma plumbing system beneath Kolumbo is critical for reconstructing its eruptive history and informing hazard assessments in this region. Using in situ tephra deposits cored during the International Ocean Discovery Program Expedition 398, this thesis reconstructs the temporal evolution of the magma plumbing system at Kolumbo over two eruptive units: 1650 CE (Unit K5) and an older eruption of ~24 ka (Unit K3/4). This research: (1) infers the pre-eruption magmatic processes and eruption initiation mechanisms, (2) determines the magma storage conditions, including pressure, temperature, and H₂O content, and (3) assesses the temporal variations in the magmatic system at Kolumbo. Results from plagioclase-melt hygrometry and melt- and mineral-based thermobarometers reveal that the K3/4 and K5 magmas were stored at similar mid-crustal depths (~9–13 km). The K3/4 eruption was likely triggered by thermal underplating and volatile saturation of a silicic reservoir (721–797 °C, 4.5–5.1 wt% H₂O). Whereas, the K5 eruption was initiated by mafic injection from a deep basaltic source (~14.8–16.3 km; 1080–1218 °C; 0.3 wt% H₂O), which passed through an intermediate melt (~14.4–14.8 km; 1025–1131 °C; 1.2–1.7 wt% H₂O) before recharging the mid-crustal silicic reservoir (758–849 °C; 3.7–4.7 wt% H₂O). These results align with present-day seismic and geophysical models and contribute to broader efforts to characterize the eruptive history and magmatic architecture of the Christiana–Santorini–Kolumbo volcanic field.

Type

Text

Keywords

Kolumbo, Santorini, Hellenic Arc, volcanology, igneous petrology, geochemistry, submarine volcanism

Publisher

Western Washington University

OCLC Number

1534553440

Subject – LCSH

Volcanology--Greece; Submarine volcanoes--Aegean Sea; Geochemistry--Greece; Volcanism--Greece; Volcanic eruptions

Geographic Coverage

Greece; Aegean Sea

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

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