Petrological Analysis of Holocene Tephra from the Antillanca Volcanic Complex, Chile

Owain Smith ¹, Amy Donovan¹ & Clive Oppenheimer¹

• Affiliations: ¹Department of Geography, University of Cambridge, Cambridge, UK

• Presentation type: Poster

• Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

• Poster Board Number: 89

• Programme No: 3.16.16

• Theme 3 > Session 16

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Abstract

The Antillanca Volcanic Complex (AVC) straddles the Chile-Argentina border. Despite its known Holocene activity and its position within the upper third of SERNAGEOMIN's 'volcano ranking' (number 26 out of 92) [1], it remains comparatively understudied, and its hazards not well characterised. Antillanca's last major explosive eruptions, dated to ~2 and 3 ka ago, sourced the Pampa Frutilla (PF) mafic ignimbrite, and the Playas Blanca Negra (PBN) tephra, respectively [2]. We present EPMA data for olivine, plagioclase and hornblende crystals from both deposits and discuss the constraints they provide on magma evolution and storage conditions (derived using MELTS) and on magma ascent during eruption. We consider implications for architecture of the AVC magmatic system and for scenarios of future unrest or activity. [1] https://magnet.cl (2020). Gob.cl - Article: National Geology And Mining Service Publishes New Volcano Ranking. [online] Government of Chile. [2] Naranjo, J.A., Singer, B.S., Jicha, B.R., Moreno, H. and Lara, L.E. (2017). Holocene tephra succession of Puyehue-Cordón Caulle and Antillanca/Casablanca volcanic complexes, southern Andes (40--41°S). Journal of Volcanology and Geothermal Research, 332, pp.109--128. doi:https://doi.org/10.1016/j.jvolgeores.2016.11.017.