Late Ordovician Tunnel Valleys

Overdeepened incisions forming tunnel valleys are remarkable geomorphic elements, which provide valuable information on past subglacial hydrological regimes and may constitute attractive reservoir targets. Geometries and distribution of Quaternary tunnel valleys have been intensively illustrated based on geophysics, while the glacial record of pre-Pleistocene glaciation offers exposures of analogous structures, from which the internal architecture and sedimentary infill can be easily delineated.