6.25 Atmospheric Processes in Caves

The cave atmosphere is placed in context as a geomorphic agent. The composition of cave air in well-ventilated caves is governed by exchange between surface and cave air. In poorly ventilated caves, its composition can be altered by dilution and production, and depletion of its components in the cave. Relative humidity is used to introduce water vapor as a critical component of cave air and its variations that result in evaporation of water and condensation of water vapor. The biogenic and inorganic reactions of oxygen and carbon dioxide control solution of limestone and precipitation of calcite. Condensation corrosion is a visual manifestation of atmospheric processes on bedrock and speleothems. Theories and experiments have resulted in rates for condensation corrosion, which allow a preliminary assessment of its role as a speleogenetic agent. The cave air carries particulates of both biogenic and inorganic origin; these can influence geomorphic processes in caves and provide significant paleoenvironmental information so as to past cave and surface events and climates. It is concluded that anthropogenic impacts can alter the atmospheric processes in caves.