A Renewed Cenozoic Story of the Strait of Dover

Abstract

The Strait of Dover is possibly an element of the European rift, subsiding from the Paleoene to the Quaternary but mostly during the Oligocene extension phase resulting from the opening of the Northern Atlantic. But as it is superimposed on a zone in tectonic inversion, the tension could be limited in expression by the reactivation of the Variscan front. The inversion of the Variscan front accommodates most of the shortening induced by the Pyrenean Orogeny and the opening of the Northern Atlantic to the Western border of the European plate. The Boulonnais depression constitutes a marine gulf from the Ypresian, already excavated during the late Cretaceous. The re-analysis of the superficial sedimentary deposits inside the Boulonnais confirms a very early opening of the Strait of Dover, from the Eocene onward. The strait is open at the end of the Lutetian, during a part of the Oligocene and the late Mio-Pliocene, faunal assemblages of these two stages being identical on both sides of the strait. It is closed again from the early Quaternary for tectonic and eustatic reasons and re-open lately just prior to the Last Interglacial. These re-openings are related with the evolution of the Eastern Channel and its palaeo-valley system. Tectonic, geomorphologic and climatic implications of this dynamic are discussed within the Western European context. The inversion of the Strait of Dover region is practically synchronic with these of the basins of the Channel and North Sea areas and the strait may be interpreted from its functioning as an element of the European rift.