The fracture permeability of Hard Rock Aquifers is due neither to tectonics, nor to unloading, but to weathering processes

摘要: The hydrogeology of superficial (∼0-100 m b.g.l.) Hard Rock Aquifers (HRA; i.e. plutonic and metamorphic rocks) has so far been dominated by a few concepts considered to be relevant large majority the HRA community. One most fundamental these is that their (secondary, fissure/fracture) permeability either tectonic origin or related unloading processes. We will show genetic are erroneous. demonstrate how hydraulic conductivity HRAs consequence (palaeo) weathering processes, with stratiform fissured layer located immediately below unconsolidated saprolite and, lesser extent, verticalized at periphery (or within) pre-existing discontinuities (veins, joints, ancient faults, lithological contacts, etc.). This result opens up perspectives in terms applied geology. A specifically dedicated methodological toolkit well adapted operational survey, management protection briefly presented.