Department of Earth Science and Engineering, Imperial College, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK.
Service of Seismology and Gravimetry, Royal Observatory of Belgium, Ringlaan, 3, Brussels B-1180, Belgium.
Nat Commun. 2017 Apr 4;8:15101. doi: 10.1038/ncomms15101.
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.
晚第四纪时期，英国与欧洲大陆的分离被认为是北海盆地南部一个大型冰前湖溢出的结果。据推断，湖溢出导致多佛海峡的一个岩石脊断裂，但这一假设仍未得到验证。在这里，我们表明海峡的开放至少涉及两个主要的侵蚀阶段。海底记录显示了一组显著的沉积物填充凹陷，这些凹陷深深地切入基岩，我们将其解释为巨大的瀑布池。这支持了一个模型，即最初是由湖水溢出导致多佛海峡的侵蚀，然后是瀑布侵蚀和随后的水坝决口。这些地貌被一个显著的基岩侵蚀山谷横切，该山谷的特征是与灾难性洪水有关的特征，表明海峡最终是被高流量决口的。这些事件为海平面高位期的英伦诸岛创造了条件，并导致了西北欧排水系统的大规模改道。
