DIPRA : a user-friendly program to model multi-element diffusion in olivine with applications to timescales of magmatic processes

Abstract

[1] Modeling the diffusion of elements in olivine from volcanic rocks has recently become one of the most useful techniques to determine the timescales of the processes that occur in magma reservoirs before eruptions. However, many potential users are not versed in the numerical methods needed to solve the diffusion equation for timescale determinations. Here we present DIPRA (Diffusion Process Analysis), a user-friendly computer tool that models easily and intuitively the olivine chemical zoning by performing an automatic, visual, and quick fit to the natural profiles. The code is developed under a finite difference scheme and allows simultaneous modeling of diffusion of Fe, Mg, Mn, Ni, and Ca. DIPRA accounts for most variables that affect the diffusivity, including temperature, pressure, oxygen fugacity, major element composition, and anisotropy. Initial and boundary conditions can be done as complex as desired, including changing boundary composition with time. Such versatility allows modeling the large variety of scenarios that are characteristic of volcanic systems. We also have implemented a methodology to estimate objectively the uncertainties of the timescales from the uncertainties of the data and temperature. We expect that our application will increase the number and quality of timescale determinations from crystal zoning studies. It may be also useful as a teaching resource for higher education courses.