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Zircon crystallization software for geological sciencesтезисы доклада
- Авторы: Bindeman Ilya, Melnik Oleg
- Сборник: IAVCEI 2023 General Assembly, Rotorua, New Zealand
- Тезисы
- Год издания: 2023
- Аннотация: In-situ zircon dating and elemental/isotopic investigation is paramount tools for petrologic investigation toreconstruct magma origin, storage, and eruption conditions and timescales. We here present an updatedversion of the Bindeman and Melnik (2016 JPet 57, 437) MATLAB code easy to use by anyone withoutprogramming experience to investigate user-specific zircon crystallization/dissolution in diversetemperature-composition-time paths. Users need to have an access to Matlab and are able to changeparameters (Zr concentration, temperature history, co-crystallization of major minerals, and their partitioncoefficient, etc) to get a ready to plot text file of results and graphs of zircon crystallization histories. Thenew version implements zirconium isotopes and Hf and other trace element concentrations and their ratios.It has two moving boundaries targeting zircon crystallization in the center of the sphere of melt, with otherminerals crystallizing in the outer boundary. Crystallization of the other phase on the outer boundary maypile up Zr and other trace element concentrations in the melt favoring more rapid zircon growth. Weincorporated a phase diagram and diffusion and partition coefficients for isotopes and trace elements,diffusion coefficients are parametrized for water concentration in melt. Kinetic vs equilibrium fractionationand partitioning processes can be investigated. For example progressively lower δ94Zr values in zircondevelop during: rapid crystallization, lower water contents, crystallization in lower T range, and whilesurrounded by Zr-poor phase; trace elemental crystallization can be modeled to result from the kineticelemental partitioning from a boundary-layer processes during slow/fast zircon crystallization. Temperaturehistory with oscillations of several degrees can result in continuous zircon growth and oscillatory zoning,greater oscillation cause zircon dissolution. We further explore zircon dissolution/crystallization history froma 2D thermochemical model of magma chamber accretion (situations with different magma flux rates), andapplied these to explain zircon record in Elbrus Volcano, Greater Caucasus.
- Добавил в систему: Мельник Олег Эдуардович