The successive roles of proglacial drainage, normal ice-age rivers and marine processes in eroding the Strait of Dover and adjacent southernmost North Sea in the last 500 ka

The removal of a landbridge in the youngest 500,000 years of Pleistocene time, disconnecting Britain and mainland Europe and joining the shelves of the English Channel and North Sea basin, is not due to a single cause. A first big ice age (probably ~450 ka ago) must have blocked drainage towards the North Sea Basin, made meltwaters pond and caused a proglacial lake to form. This caused a spillway river to emerge which was the start of erosive removal. But more glacial-interglacial cycles followed that also contributed to erosion! Normal low stand rivers caused valley cutting and high-stand marine tides and waves stripped sea floor and attacked cliffs. To complicate matters, the penultimate glacial and perhaps also the last glacial saw returned proglacial lakes at lower levels than before. The last glacial saw a major Rhine-Thames southward river valley: an oasis through less hospitable interfluve area. An evolving story.
One thing we can be sure of with this successive erosion, is that repair of erosion did never occur. Each next erosive process followed up on a previous process, and it is the relative effectiveness of the chain of erosive agents that explains how a dirty estimated total of 50,000*30,000*70 m3 of Cretaceous chalk, and 100,000*180,000*45 m3 of Eocene clays and sands, could be removed from the area in the youngest 500 ka. Understanding the erosion history of the Strait of Dover and the adjacent southernmost North Sea is a matter of evaluating erosive power of follow-up geomorphic agents. We do this for dramatic times with spilling ice lakes (very effective in retrograding erosion in the 5-10 ka that these lakes can have existed at longest) and for long times with rivers in-between (several 100k) and for marine high stand interruptions (briefer episodes again). The work has implications for paleolithic human migration, for southward sediment transport magnitudes, for the routing of ice-age runoff and for upstream basin sedimentation.