干旱区生态环境知识资源中心

New palynological investigations have been carried out in the southern, northern and Mediterranean part of the Pyrenean chain. Pollen percentage and concentration diagrams are compared for a period including the end of the glacial period, the Late Glacial and Postglacial periods. From the new results and from comparisons with previous published data, the steppe and semi-desert vegetation of the end of the last glacial period are described, as well as the plant communities of the period 15-13 ka. A dry climate was responsible for the early glacial retreat before 30 ka. Deglaciation was continuous up to about 15-14 ka, without any readvance around 20-18 ka. Different aspects of the Late Glacial vegetation are studied and the first stages of the Postglacial are described. The Younger Dryas event is found everywhere, but particularly clearly in the Mediterranean area. The most important C-14 dates are discussed, and a plateau of C-14 ages is clearly visible around 10,000 BP.