Two-stage opening of the Dover Strait and the origin of island Britain

Sanjeev Gupta,Thierry Camelbeeck,David Garcia-Moreno,Jenny S Collier,Brigitte Van Vliet-Lanoë,Francesca Oggioni,Marc De Batist,Kris Vanneste,John C R Arthur,Alain Trentesaux,Graeme Potter

doi:10.1038/ncomms15101

Abstract

Late Quaternary separation of Britain from mainland Europe is considered to be a consequence of spillover of a large proglacial lake in the Southern North Sea basin. Lake spillover is inferred to have caused breaching of a rock ridge at the Dover Strait, although this hypothesis remains untested. Here we show that opening of the Strait involved at least two major episodes of erosion. Sub-bottom records reveal a remarkable set of sediment-infilled depressions that are deeply incised into bedrock that we interpret as giant plunge pools. These support a model of initial erosion of the Dover Strait by lake overspill, plunge pool erosion by waterfalls and subsequent dam breaching. Cross-cutting of these landforms by a prominent bedrock-eroded valley that is characterized by features associated with catastrophic flooding indicates final breaching of the Strait by high-magnitude flows. These events set-up conditions for island Britain during sea-level highstands and caused large-scale re-routing of NW European drainage.

Highlights

Late Quaternary separation of Britain from mainland Europe is considered to be a consequence of spillover of a large proglacial lake in the Southern North Sea basin
Because the valleys in the central Channel are interpreted to have formed by erosion by high-magnitude flood flows[5,7], their continuity with the Lobourg Channel suggests that incision of this prominent feature was likely a related process
While it is widely held that initial opening of the Strait was a consequence of spillover of a proglacial lake that existed in the southern North Sea basin during MIS12, direct evidence for this spillover process has up to now been lacking

Summary

Introduction

Late Quaternary separation of Britain from mainland Europe is considered to be a consequence of spillover of a large proglacial lake in the Southern North Sea basin. The depth of erosion into bedrock at the seafloor associated with the cataracts is evidence of powerful erosional processes, it should be noted that the magnitude of these is much smaller than the Fosses Dangeard depressions that we interpret as plunge pools.

Results

Conclusion