Diffuser: A user-friendly program for diffusion chronometry with robust uncertainty estimation

Chemical diffusion in minerals has shown great potential to quantify timescales of geological processes. The presence of chemical gradients, along with favorable temperature and time conditions, lead to the formation of measurable diffusion profiles. Temporal information can be extracted from measured diffusion profiles using either analytical or numerical solutions of Fick's second law. Currently, there is a lack of widely adopted programs for diffusion studies. In addition, the uncertainties associated with timescales derived from diffusion chronometry are critical for geological studies, but are not always robustly evaluated. In many cases, only uncertainties in curve fitting parameters and temperature are considered, whereas other uncertainties, such as those associated with the experimentally determined diffusion coefficients themselves, are rarely propagated into the calculated timescales. Ignoring these uncertainties reduces the reproducibility and intercomparability of results. In response to these challenges, we present Diffuser, a user-friendly program to standardize diffusion chronometry with transparent and robust propagation of uncertainties. Using analytical and numerical methods, our program provides an automatic, visual, and efficient curve fit to extract chronological information from diffusion profiles. The method is complemented by an algorithm to propagate all uncertainties (i.e., measurement, temperature, curve fitting, and diffusion coefficient) to derived timescales. Three examples are provided to highlight how the program can recover timescales with internal consistency, efficient computing, and easy-to-use features. Our freely available and user-friendly program will hopefully increase the accessibility and consistency of diffusion modeling and thereby to facilitate more high-quality diffusion studies