The beginning of torrentiality in La Fontarasse Basin (Barles, Alpes-de-Haute-Provence, France), evidence for an Ancient Holocene climatic break

In the southern French Alps, we studied some subfossil tree remains from a small forest, destroyed by a mud-flow before being buried under thick torre ntial deposits and then recently exposed again by erosion. The C-14 age of the wood allows us to propose nearly 7900 years BP for the beginning of the current erosional stage. we can also show that the original disaster was d ue to natural factors and not at all due to human ones. The trees grew for a few hundred years, during a short quiet period between that of intense er osion after the end of the Pleistocene and the usual interglacial morphocli matic instability times, the natural effects of which were increased by hum an activities. ((C) Academie des sciences / Elsevier, Paris.).