Quaternary hydrological development in the Morecambe Bay karst, northwest England

The distribution of active and abandoned caves in the Morecambe Bay karst is indicative of at least two phases of subsurface drainage development, separated by an episode of valley incision, landscape dissection and surface lowering. It is suggested that the phase of erosion was associated with glaciation by ice from the adjoining Cumbrian massif, and that the earlier phase of drainage development was of at least last interglacial age. This view is supported by the evidence of the age and mode of deposition of the sedimentary infill in the caves, and by estimates of cave palacocatchment area. The caves of the earlier phase of drainage development were formed in valleys that were already deeply incised. It would therefore appear that the last glaciation only succeeded in slightly modifying an existing topography, a view at odds with conventional ideas of landscape development in Cumbria as a whole.