The fracture permeability of Hard Rock Aquifers is due neither to tectonics, nor to unloading, but to weathering processes - BRGM - Bureau de recherches géologiques et minières Access content directly
Journal Articles Terra Nova Year : 2011

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

Abstract

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 by a large majority of the HRA community. One of the most fundamental of these concepts is that their (secondary, fissure/fracture) permeability is either of tectonic origin or related to unloading processes. We will show that these genetic concepts are erroneous. We will demonstrate how the hydraulic conductivity of HRAs is a consequence of the (palaeo) weathering processes, with a stratiform fissured layer located immediately below the unconsolidated saprolite and, to a lesser extent, a verticalized fissured layer at the periphery of (or within) pre-existing discontinuities (veins, joints, ancient faults, lithological contacts, etc.). This result opens up large perspectives in terms of applied hydrogeology and applied geology. A specifically dedicated methodological toolkit well adapted to the operational survey, management and protection of HRAs is briefly presented.

Domains

Earth Sciences

Dates and versions

hal-00677122 , version 1 (07-03-2012)

Identifiers

Cite

Patrick Lachassagne, Robert Wyns, Benoît Dewandel. The fracture permeability of Hard Rock Aquifers is due neither to tectonics, nor to unloading, but to weathering processes. Terra Nova, 2011, 23 (3), pp.145-161. ⟨10.1111/j.1365-3121.2011.00998.x⟩. ⟨hal-00677122⟩

Collections

BRGM BRGM-DO
89 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More