贵州黔西观音洞钟乳石样的铀系年龄

U-SERIES DATING OF SPELEOTHEM SAMPLES FROM GUANYINDONG CAVE AT QIANXI COUNTY, GUIZHOU PROVINCE

Guanyindong Cave, situated at Qianxi County in Guizhou Province, with an abundance of paleolithic artifacts and of fossil remains', is considered as one of the most important paleolithic sites in South China. The Ailuropoda-Stegodon fauna of Group B deposits was assumed to be formed in early Middle Pleistocene judging mainly by the existence of Tertiary survi vals, and Group A deposits without Tertiary survivals in Middle Pleistocene. The biostrati-graphic conclusion contradicts sharply with the results of U-series dating of fossil bones which give an age range of 57-115 ka for all the artifact and fossil containing layers.Based on the U-series dating of speleothem samples, the Group A deposits of this site should be younger than 40 ka, the 3rd layer of Group B younger than 50 ka, and 4-8 layers of Group B between 50 and 240 ka. If the stratigraphic study may prove the uniformity of Group B deposits, the age of 4-8 layers may be further narrowed to 100-190 ka. The results of this paper do not support the biostratigraphic relative age, but confirm that the lower part of Group B belongs to a late period of Middle Pleistocene, being the latest fossil record of Gomphotheriidae. This site may represent the cultural evolution traversing the lower, middle and upper paleolithic periods in South China.