Date and Time
Bath Royal Literary and Scientific Institution, 16-18 Queen Square, Bath BA1 2HN
Megaflood events involving sudden discharges of exceptionally large volumes of water are rare, but can significantly affect landscape evolution, continental-scale drainage networks and climatic patterns. In this talk, Dr. Collier will present a new regional bathymetric map of part of the English Channel derived from high-resolution sonar data, which shows the morphology of the seabed in unprecedented detail. These data image a large bedrock-floored valley that contains a distinct assemblage of landforms, including streamlined islands and longitudinal erosional grooves, which are indicative of large-scale subaerial erosion by high-magnitude water discharges. The data support a megaflood model, in which breaching of a rock dam at the Dover Strait instigated catastrophic drainage of a large pro-glacial lake in the southern North Sea basin. It is suggested that this event permanently isolated Britain from mainland Europe and prompted a large-scale reorganization of river drainage patterns across northwest Europe. In turn these consequences significantly influenced the patterns of early human colonisation of Britain.
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