Researcher ORCID Identifier

0009-0008-1823-9200

Graduation Year

2024

Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts

Department

Geology

Reader 1

Nicole Moore

Reader 2

Jade Star Lackey

Reader 3

Colin Robins

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Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2024 Lucy Smith

Abstract

Mount Ruapehu is a large stratovolcano on the North Island of Aotearoa New Zealand. The Rangataua lava flow is situated on the southern flanks of Ruapehu, and extends for 15-16 km. The flow is of andesite composition and comprised of three units: proximal, medial and distal. Mount Ruapehu is both scientifically and culturally significant.

Geochemical analyses of 13 whole rock samples, Electron Microprobe analyses of three polished thin sections, and geothermobarometry calculations were conducted to obtain data on pre-eruptive intensive parameters. Petrographic observations were used to investigate disequilibrium textures and shed light on magma chamber processes.

Results of this study support the notion of three distinct flow units of Rangataua that each erupted at different pressures and temperatures. The most distal unit that traveled the furthest from the vent shows the highest pre-eruptive temperature conditions. The presence of disequilibrated phenocrysts suggests that the magma plumbing system that feeds Ruapehu is complex and has multiple different sources of recharge.

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