Crustal permeability: Introduction to the special issue

摘要: The topic of crustal permeability is broad interest in light the controlling effect on diverse geologic processes and also timely practical challenges associated with emerging technologies such as hydraulic fracturing for oil gas production (‘fracking’), enhanced geothermal systems, carbon sequestration. This special issue Geofluids motivated by historical dichotomy between hydrogeologic concept a static material property that exerts control fluid flow perspective economic geologists, geophysicists, petrologists who have long recognized dynamic parameter changes response to tectonism, production, geochemical reactions. Issues fracking, sequestration already begun promote constructive dialog views permeability, here we made conscious effort include both viewpoints. focuses quantification encompassing direct measurement uppermost crust inferential estimates, mainly deeper crust. directly measured (k) common media varies approximately 16 orders magnitude, from values low 10 m intact crystalline rock, shales, fault gouge, high well-sorted gravels. Earth’s upper can be regarded process-limiting parameter, it largely determines feasibility advective solute transport (k ~ >10 20 m), heat ≥10 generation elevated pressures ≤10 17 m) – which turn are essential ore deposition, hydrocarbon migration, metamorphism, many other fundamental phenomena. hydrodynamics fluids brittle crust, where topography magmatic sources dominate patterns externally derived (meteoric) (e.g. Howald et al. 2015) distinct ductile lower dominated devolatilization reactions internally Connolly & Podladchikov, 2015). brittle–ductile transition these regimes occurs at 10–15 km depth typical continental Permeability below non-negligible, least active orogenic belts (equivalent mean bulk k order 19 18 so underlying regime an important source Ingebritsen Manning 2002). overall objective this synthesize current understanding through representative publications multiple disciplines. introduction define crucial nomenclature ‘static’ ‘dynamic’ perspectives briefly summarize contents issue, divided into following sections: physics permeability.