Impact of weathering on permeability-depth trends in bedrock aquifers

Weathering and compression are important processes that influence how permeability varies with depth below the Earth’s surface. Analysis of permeability measurements suggests that the rapid permeability decrease in shallow crystalline bedrock to a depth of ~200 m is primarily a function of weathering, and that compression causes a steady reduction in permeability with depth. The depth of the base of weathering increases with rock dissolution rate, and varies from ~20 m in shale to sometimes >1,000 m in carbonate rocks.