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From hours to centuries: using DiffSim to determine magmatic timescales in diverse mineral phases

Eduardo Morgado1, Daniel J. Morgan2, Brandon Candia1, Andrea Rauch1, Mariana Marhcant3

  • Affiliations: 1 Escuela de Geología, Universidad Mayor, Santiago, Chile. 2 School of Earth and Environment, University of Leeds, Leeds, UK. 3 Departamento de Geología, Universidad de Chile, Santiago, Chile.

  • Presentation type: Poster

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

  • Poster Board Number: 69

  • Programme No: 1.2.14

  • Theme 1 > Session 2

Abstract

DiffSim is a new software tool that enables magmatic timescale calculations via diffusion chronometry modelling of major elements in solid phases such as olivine, orthopyroxene, titanomagnetite, and melt. Available as executable freeware, DiffSim makes it accessible for researchers and students to use diffusion chronometry for precise insights into crustal processes. In addition to calculating precise magmatic timescales, DiffSim incorporates error propagation, offering maximum and minimum timescale estimates to enhance the reliability of its results. DiffSim models diffusion based on the exposed crystal orientation, requiring the plunge, trend of the (001)-axis, and 2D section angle. Additionally, users define the initial composition-distance profile, time resolution, and intensive parameters (e.g., temperature, pressure, oxygen fugacity). We tested DiffSim in two case studies within the Southern Volcanic Zone of the Chilean Andes: the 2015 eruption of Calbuco and the Neltume tephra of Mocho-Choshuenco (~11,500 years ago). Zoned crystals of titanomagnetite, olivine, and orthopyroxene in these samples yielded timescales ranging from hours (Calbuco), which likely reflect the eruptive trigger, to several years (Mocho-Choshuenco), indicating residence in an upper crustal reservoir.