Date of Graduation

Summer 2026

Degree

Master of Science in Geography & Geology

Department

School of Earth, Environment & Sustainability

Committee Chair

Gary Michelfelder

Abstract

The Água de Pau Volcano has been extensively studied due to its Plinian “Fogo A” eruption, which entrained syenite clasts as xenoliths within Fogo “A” pumices. This provides an opportunity to investigate volcanic–plutonic connections, although the relationship between these components remains poorly constrained, with limited published zircon geochronology from the Fogo volcanic system. To constrain magma storage conditions and crystallization history, we conducted U–Th zircon geochronology and trace-element geochemistry using SHRIMP-RG and LA-ICP-MS, respectively, on pumices from successive stratigraphic units spanning 12 to 3.2 ka (Fogo B, Fogo A, Pisão, and Ribeira Chã) and syenite clasts from the Fogo “A” unit. U–Th zircon data indicate complex age distributions, with weighted mean zircon ages from pumice samples showing overlapping populations across units. Zircon ages range from ~10 ka to 200 ka, suggesting prolonged zircon residence in a long-lived magmatic system. Kernel density estimates reveal multiple age peaks, consistent with episodic crystallization. Trace-element data (Ti, Eu/Eu*, Zr/Hf and Th/U) show systematic variations across the stratigraphy, consistent with progressive magmatic differentiation. These observations support a long-lived, periodically rejuvenated magma reservoir beneath Água de Pau volcano, characterized by episodic recharge, thermal reactivation, and melt extraction.

Keywords

Plutonic-volcanic connection, magma storage, magma recharge, incremental magma assembly, Fogo Volcano, zircons, long-lived magmatic system, syenite xenoliths, crystal mush magma reservoirs, thermal rejuvenation

Subject Categories

Geochemistry | Geology | Volcanology

Copyright

© Josephine Opare Dankwa

Download

Available for download on Tuesday, July 20, 2027

Open Access

Share

COinS