Dependence of Simulated Fault Gouge Frictional Behavior on Mineral Surface Chemistry Quantified by Cation Exchange Capacity

Abstract The slip behavior of crustal faults is known to be controlled by the composition of the fault gouge, but the exact mechanisms, especially considering the role of water‐rock interactions, are still under investigation. Here, we use a geochemical approach measuring the cation exchange capacity (CEC) of several phyllosilicate minerals and non‐clays, using CEC as a proxy for the ability to bind water to the mineral surfaces and/or develop electrostatic forces between particles. Laboratory shearing experiments show that low CEC materials (