NATIONAL DATABASE ON PLEISTOCENe PERMAFROST
Pascal Bertran (PACEA, CNRS, University of Bordeaux 1)
Partners: CRPAA - LGP Meudon
Duration: 3 months (1st October 2012 – 31st December 2012)
Temporary recruitment: Eric Andrieux
The extension of pleistocene permafrost in France remains unknown and controversial. Recent work, especially in Aquitaine, enabled the finding of unprecedented data which invalidate the European-scale reconstitutions published recently. The OSL dating of the fossil periglacial structure filling (frozen grounds, ice wedges) makes it possible to establish a chronology of the different permafrost extension phases and to compare it with the climate change documented in a glacial and sea environment. The characterisation of structures and their interpretation with a palaeoenvironmental approach, based on recent actualist studies, is also a way to find out more about associated palaeoclimatic conditions.
The study of these periglacial structures thus opens new perspectives in the knowledge of palaeoenvironments contemporary with palaeolithic occupations. The compilation of radiocarbon dates collected on the French palaeolitc sites seems to show that permafrost phases had a major impact on settlement. France, located between Northern Europe, which was covered by permafrost permanently during Last Glacial Maximum and the Iberic Peninsula, which avoided permafrost incursions, is the ideal study field to address this issue.
|Decametric polygons, Villeneuve-sur-Allier. Photo IGN.||Decametric polygons, Villeneuve-sur-Allier. Photo IGN.|
|Simplified geological map of France (BRGM) and geographic distribution of periglacial features.|