Multiple Kinetic Parameterization in a Reactive Transport Model Using the Exchange Monte Carlo Method

Minerals

Noriyoshi Tsuchiya¹  Atsushi Okamoto¹  Ryosuke Oyanagi² 

[1] Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan;Department of Solid Earth Geochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan;

关键词: reaction rate;    reaction kinetics;    reactive transport modeling;    data-driven approach;    optimization;    Markov chain Monte Carlo;    exchange Monte Carlo method;    geochemical inverse problem;   

DOI  :  10.3390/min8120579

来源: DOAJ

【 摘 要 】

Water⁻rock interaction in surface and subsurface environments occurs in complex multicomponent systems and involves several reactions, including element transfer. Such kinetic information is obtained by fitting a forward model into the temporal evolution of solution chemistry or the spatial pattern recorded in the rock samples, although geochemical and petrological data are essentially sparse and noisy. Therefore, the optimization of kinetic parameters sometimes fails to converge toward the global minimum due to being trapped in a local minimum. In this study, we simultaneously present a novel framework to estimate multiple reaction-rate constants and the diffusivity of aqueous species from the mineral distribution pattern in a rock by using the reactive transport model coupled with the exchange Monte Carlo method. Our approach can estimate both the maximum likelihood and error of each parameter. We applied the method to the synthetic data, which were produced using a model for silica metasomatism and hydration in the olivine⁻quartz⁻H₂O system. We tested the robustness and accuracy of our method over a wide range of noise intensities. This methodology can be widely applied to kinetic analyses of various kinds of water⁻rock interactions.

【 授权许可】

Unknown