Comment on 'A Simple Model for Regolith Formation by Chemical Weathering' by Braun et al.: Contradictory Concentrations and a Tale of Two Velocities

摘要

An intriguing model has been presented predicting that the rate of deepening of the critical zone is proportional to lateral hydraulic gradients in a hillslope's perched aquifer. Unfortunately, the model is based on assumptions that lead to a contradiction and the prediction that discharge concentrations are supersaturated with respect to weathering products. Consequently, the remainder of the paper's deductions from the model cannot be regarded as valid. A corrected version of the model implies that deepening of the critical zone is proportional to local recharge, and not to lateral water table gradients.