The formation of the Strait of Dover

Abstract

The Strait of Dover (Pas-de-Calais) is a narrow sea passage that links the North Sea and the English Channel between Britain and France. Much evidence suggests that the Dover Strait did not exist throughout most of the Pleistocene. Instead, a Chalk barrier was present, formed by the Weald-Artois anticline. Advance of the continental ice-sheet across the North Sea in the Middle Pleistocene Elsterian/Anglian Stage apparently dammed the southern part of the basin and water discharging into it was prevented from reaching the Atlantic to the north. The resulting lake apparently drained by spilling over the barrier and initiated the gap. This scenario is supported by sediments at Wissant, France. This theory contrasts with one, proposed by French geologists, that favours a structural origin.Overflow from the lake has been interpreted as having been catastrophic. This was invoked to explain the origin of the complex anastomosing system of valleys or channels that occurs on the floor of the Channel cut into bedrock, predominantly of Mesozoic age. These valleys are interlinked to form a drowned drainage system and can also be linked to present rivers that enter the Channel on both the British and French sides. However, it is highly probable that the drowned valley system is multigenetic, resulting from repeated fluvial and marine erosion and deposition rather than representing a single, short-lived event. The valley system probably originated in the late Early to early Middle Pleistocene as a consequence of uplift of the Weald-Artois region.Once the Dover Strait was formed, the rivers Thames and Scheldt were deflected through the gap and into the Channel River system during periods of low relative sea-level. Subsequently these rivers were probably joined by the Maas and Rhine, diverted by glaciation in the Drenthe Sub-stage (Saalian/Wolstonian Stage). The narrows seem to have been progressively enlarged by marine tidal scour and coastal erosion during high sea-level events.The island of Great Britain is separated from France by the Strait of Dover (Pas-de-Calais) ( Fig. 1). This sea passage is 34km wide at its

North Sea palaeogeographical reconstructions for the last 1 Ma

“…Winsemann et al, 2004) and west (e.g. Gibbard, 1995) of the present-day North Sea, river valleys relatively close to the ice front were temporarily occupied by proglacial or ice-dammed lakes. The largest-scale ponding occurred when Scandinavian and British ice fronts joined and blocked northward meltwater drainage.…”

“…Although theories on the timing and pacing of the opening of the Strait still have to be substantiated by other than erosional geomorphological evidence, the hypothesis that this started in the Anglian and is related to massive spillage of proglacial water from the North Sea Basin towards the south (Gibbard, 1988(Gibbard, , 1995 has far-reaching bearings on northwest Europe's Middle and Late-Pleistocene archaeological record and on the history of man as inferred from it. These bearings are not found as much in the would-be catastrophic events, which are attributed a key role in the formation of the Strait of Dover in some versions of the hypothesis (e.g.…”

Fluvio‐Deltaic Floodbasin Deposits Recording Differential Subsidence within a Coastal Prism (Central Rhine–Meuse Delta, The Netherlands)

“…Thus, the river followed a glacially imposed course, oblique to the structural trend, forcing it to cross relatively stable blocks before entering the Roer Valley Graben in the study area (Cohen et al, 2002). An alluvial valley formed during OIS 4-2 Wallinga, 2001) as sea level had dropped considerably, exposing the North Sea floor and extending the Rhine river several hundreds of kilometres (Gibbard, 1995). In the Late-glacial (OIS 2-1 transition) rivers incised in response to climatic amelioration.…”

Fluvial deposits as a record for Late Quaternary neotectonic activity in the Rhine-Meuse delta, The Netherlands

“…The Lateglacial rivers followed a course through the southern North Sea and the English Channel (Bridgland & D'Olier, 1995). During the formation of the terraces, sea level was >50 m lower, and the coastline was located downstream of the Strait of Dover (Gibbard, 1995). In the Late Weichselian, hard rock in the Strait of Dover (at 40-50 meters below present sea level) probably controlled base level of the Rhine and the Meuse in the Netherlands.…”