The role of temperature in processes controlling weathering rates of carbonate lithologies and volcanic systems

Abstract

Two main lithological classes that have the highest observed weathering fluxes on Earth, carbonate and volcanic rocks, represent important components in the carbon cycle.The aim of this work is to explore processes, previously neglected, that can control global weathering rates in carbonate lithologies and volcanic systems: (i) the role of temperature on controlling global weathering rates of carbonate minerals; and, (ii) the role of elevated temperature processes beneath volcanic areas in total weathering fluxes. Results show that carbonate weathering at global scale can be quantified implementing thermodynamic equations and considering the partial pressure of CO 2 in the soil profile, where the deepening of the weathering front in carbonate lithologies, mostly located in tropical regions, reduces the weathering rates significantly. Furthermore, to address the hydrothermal contribution to weathering fluxes, natural waters from Aso caldera, one of the most actives volcanoes in Japan, are analysed to quantify mixing processes with volcanic gases by determining stable isotopes of carbon and sulphur and applying Se:S molar ratios.