Phytolith assemblages and their environmental significance in the Chuanfan Cave, Wanshouyan Site, Fujian

Two-stage cultural layers (40～37 kaBP and 30～29 kaBP) were identified in the Chuanfan Cave, Wanshouyan Site, Sanming, Fujian Province. The artificial pebble-laid living surface in the first cultural layer was an important discovery in paleolithic reconnaissance, which has great significance in investigating the living environment in the last glacial period. Systematic phytolith analysis of deposits in the Chuanfan Cave provided us an opportunity to reveal climatic change and the living environment of ancient humans since late Pleistocene. Results show that acicula and rhabdolith were dominant in all samples, followed by fan-shaped and blocky phytolith, and more saddle-shaped phytolith in short cell. Five climatic stages were divided from bottom to top according to phytolith assemblages: cool dry, cold dry, in relatively dry cold, relatively dry cool, and relatively warm dry. The first ancient human lived in the early stage Ⅰ, which was relatively warm in cool-dry background. The second ancient human lived in the late stage Ⅳ, which was relatively warm in cool-relatively-dry background. Phytolith variation also indicated that the Heinrich events H4 and H3 correspond well to the two cultural layers. The climate tended to be cooler rapidly after the two Heinrich events, which changed the living environment of ancient humans and shall be the main reason for the ancient humans in the two stages to escape from the Chuanfan Cave.