A recent AGU Chapman Conference on “Crustal-Scale Fluid Transport: Magnitude and Mechanisms” reflected a contradiction between, on the one hand, the near hydrostatic pressure conditions and continuous fluid flow description that form the basis of hydrological modeling; and on the other, the deeper rock record that demands an episodic process with both fracture-controlled flow and high pressure (near lithostatic) conditions. The more complex fluid-flow picture observed in the rock record has not been described in a form that can be readily incorporated into the existing computational models of fluid flow in the bulk crust.

The multitude of rock types in the Earth's crust cannot have resulted solely from closed-system reactions. The processes recorded in the rock testify to the extent of fluid/rock reactions, open-system kinetics, and large-scale fluid transport in the crust. The extent of this fluid transport has become increasingly apparent, but the processes generally are not directly observable. The mechanisms involved in these open-system reactions and the magnitude of fluid mass transport must be inferred from the reaction products and from a theoretical understanding of the fluid mechanics, rock mechanics, geophysics, geochemistry, and regional tectonics.