A MULTIDISCIPLINARY INVESTIGATION OF A HOLOCENE LAKE SEDIMENT SEQUENCE IN THE SOUTHERN FRENCH ALPS AT LAKE PETIT (MERCANTOUR, 2200 M ASL, FRANCE): HISTORY OF A DISTURBED GEOSYSTEM

作者：Brisset Elodie^*; Guiter Frederic; Miramont Cecile; Delhon Claire; Arnaud Fabien; Disnar Jean Robert; Poulenard Jerome; Anthony Edward; Meunier Jean Dominique; Wilhelm Bruno; Pailles Christine

来源：Quaternaire, 2012, 23(4): 309-319.

DOI：10.4000/quaternaire.6390

• lacustrine sediment
• soil erosion
• human impact
• vegetation
• pollen
• Holocene
• French Southern Alps
• 4.2 ka event

High resolution multiproxy analyses, including sedimentological, geochemical and palynological investigations, were carried out on a 144-cm-long sediment profile from Lake Petit (2 200 m a.s.l., Vallon des Millefonts, Mercantour, in the French Southern Alps). This allowed us to reconstruct complex interactions between climate, environment and human during the Late Holocene. We identify three phases: (1)a first phase (4 750 to 4 350 cal. BP) characterized by a dominant lake sedimentation and developed soils on slopes, (2) a second period (4 350 to 1 550 cal. BP) marked by an abrupt switch in sediment source and an input of organic allochthonous matter linked with soil erosion and a more open landscape, (3) a final phase (since 1 550 cal. BP) of intense destabilization of slopes. Even if climate could have triggered such drastic changes, discreet but continuous human impact until 1 550 cal. BP might be the main factor of degradation of slopes and ecosystems in the valley. The record of abundant terrigenous input also suggests that high-intensity rainfall events might have occurred, while agro-pastoralism and local mining activities continuously weakened slopes.

• 出版日期2012-12