长江中下游地区网状红土和下蜀土的微体植物群与第四纪气候

After a systematically study on the micro-floras of the patterned laterite and Xiashu loess in the middle-lower reaches of the Yangtze River, a more or less complete variation pattern on climate in the Middle-Late Pleistocene of the region has been revealed. Phytoliths in the patterned laterite of Xuancheng County show climate variations, which are well correlated with MIS-5 to MIS-23 of the global nature of marine oxygen isotope stages (MIS), reflecting for the first time that laterite in South China was formed under the global climatic control to certain extent. Study on climate index of the profile also shows that laterite was more possibly formed under Pleistocene interglacial environment. Although glacial condition are not favorable to the red earth formation, our study also reveals that laterite could be partly formed in some warm periods in the ice age. This supplies new evidence for the mechanism on the formation of laterite. Phytolith study on the loess profile (comparable with the Xiashu loess) in Shengshan Island displays four arid and humid cycles about 50-10 Ka BP. Among these cycles, the warmest climates are recognized in the humid period of the first cycle, and the arid period of the third cycle, reflecting the climatic feature at that time in one aspect. Micro-floral study on the Homo erectus' cave deposits in Nanjing exhibits the Pleistocene climate feature of four profiles in the cave, and it is thus made known that the layer bearing Nanjing hominid cranium (Skull I) was of glacial condition. During the period of this project, studies on the surface samples and modern reference catalogue of plants greatly increase the accuracy of the phytolith identification. The proposal for the establishment and application of climate indexes including warm index and arid index, has effectively improved the explanation of the fossil data from the strata. At the same time, many results we got are fully exchanged both at home and abroad, including the further international cooperation afterward.

研究网纹状红土和下蜀土的植硅石和孢粉，建立微体植物群组合。结合现代表土和相关现代植物硅石形态的研究，定量恢复沉积时期的气候和干湿指标。建立与我国北方黄土气候序列的对比关系，并探讨全球气候变化在我国亚热带北界的纬度效应。结果可弥补相关层位生物研究的空白，为过去全球变化提供新证据；同时推动植硅石这一新的研究领域在我国的开展。