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Influence of Deformation on Crystallization: Experimental Insights on Magma Conduit Dynamics

Alessandro Musu 1,2, Luca Caricchi2, Francesco Vetere4, Thomas Griffiths1, Maurizio Petrelli3, Rosa Anna Corsaro5, Stefano Peres1, Alessandro Pisello3 & Diego Perugini3

  • Affiliations: 1Department of Lithospheric Research, University of Vienna, UZA2, Josef-Holaubek-Platz 2, 1090 Vienna, Austria; 2Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, CH-1205 Geneva, Switzerland; 3Department of Physics and Geology, University of Perugia, Piazza dell'Università, 1, 06123 Perugia, Italy; 4Department of Environment, Earth and Physical Sciences, University of Siena, Via Laterina, 8, 53100 Siena, Italy; 5Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo-Sezione di Catania, Catania, Italy

  • Presentation type: Poster

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

  • Poster Board Number: 78

  • Programme No: 1.2.23

  • Theme 1 > Session 2

Abstract

Crystallization processes in trans-crustal magmatic systems play a critical role in shaping magma rheology, conduit dynamics, and eruptive behavior. The presence of a deformation field within plumbing systems can significantly impact crystal nucleation and growth. This study makes use of novel crystallization experiments to quantify the impact of deformation on nucleation, crystallization, mineral phase proportions, and residual melt composition. The experiments were performed on natural trachybasalts from Mt. Etna, under controlled pressure and temperature conditions at the University of Perugia. Mineral zoning was forced by oscillating the temperature (1170 - 1130 °C) while a strain rate gradient was imposed with a concentric cylinder apparatus with the spindle rotating at constant strain rate. Mineral and glass chemical variations were analyzed using an electron probe microanalyzer (EPMA) at the University of Geneva. The data were analysed using custom-built unsupervised and supervised machine learning algorithms (e.g., Hierarchical Clustering and Random Forest). The effect of deformation on nucleation, growth, and mineral phase proportions was quantified using backscattered electron diffraction (EBSD) at the University of Vienna. Results show that deformation enhances nucleation rates, increases crystal number density, and alters mineral phase proportions and thus the composition of the residual melt. These findings highlight the need to consider deformation processes when interpreting the textural and chemical variability of volcanic products. Finally, we explore the potential links between our experimental results and the chemical evolution of magma at Mt. Etna during the 2021 eruptive sequence at the South-East summit crater, suggesting possible implications for conduit dynamics.