master cave

   Best defined as a low level trunk streamway cave with many tributaries. The old concept of the master cave being formed at the water table should be disregarded. The Leck Fell Master Cave, in the Yorkshire Dales, is 2km long, partly a vadose canyon, partly a drained phreatic tube and partly a submerged tube. Part of it therefore lies below the water table while elsewhere its presence controls the water table. The French equivalent, ‘collecteur’, is more descriptive of the master cave’s true role. The depth to a currently active master cave is dictated by interactions between local topography, stratigraphical factors and geological structure. In the low hill karst of England and Kentucky, active master caves lie at depths of around 100m, but in Monte Canin, Italy, and the Hautla Plateau, Mexico, they lie at depths of 1000m. The collecteur of the Gouffre Berger, France, is met just 250 m down but can be followed to a depth of over 1000m, down the dipping limestone beds, thus emphasizing the local dominance of stratigraphical over topographical factors [9].