44.5. EUSTATIC HYPOTHESIS AND CUTTING OF RHONE VALLEY

The finding of an extensive layer of evaporites in the deep drillings in the Mediterranean revives a new interest in the hypothesis of a temporary isolation of this sea at the end of the Miocene. Since this idea has already received support from the interpretation of boreholes within the Rhone Valley in southern France, I have been invited to first trace the history of this hypothesis, and then examine how it provides a unique solution to a number of problems of continental paleogeography. BACKGROUND AND HISTORY OF THE "DENIZOT HYPOTHESIS" The eustatic hypothesis is far from being a new idea. Ever since Depéret (1895), it has been entertained by a number of authors. However, they always relied on a worldwise cause for sea-level change without ever reall