网纹红土中的植硅石组合及其环境意义的初步研究

A PRILIMINARY STUDY ON PHYTOLITH ASSEMBLAGES AND ITS PALEOENVIRONMENTAL INDICATION OF THE VERMICULAR RED EARTH

长江中下游地区网纹红土中的古气候记录，在第四纪全球变化研究中具有十分重要的意义．简述了江西修水网纹红土的岩性特征和形成时代，重点讨论了网纹红土中的植硅石及其古气候信息．根据植硅石形态的环境意义，结合因子分析（Ｒ型和Ｑ型），将修水剖面网纹红土所含的植硅石划分为１２个组合带．通过与磁化率和地球化学气候标志的对比，在形成于距今大约０．９～０．１Ｍａ的网纹红土中，识别出６个气候旋回，并将其与黄土—古土壤气候旋回和深海氧同位素气候旋回进行了对比。

The paleoclimate records of the vermicular red earth in the Middle-Lower Yangtze Region is of great significance to the study of the global changes in Quaternary. The paper briefly introduces the lithologic features, and accumulation age of the vermicular red earth and mainly elaborate phytolith in it and its paleoclimatic indication. Based on the study of various forms of phytolith and main factor analysis (R-and Q-mode analyses), phytolith in the vermicular red earth of Xiushui is divided into twelve assemblage zones indicating 12 climate periods. When these zones are compared with the magnetic susceptibility and geochemical paleoclimatic indexes, six paleoclimate cycles are recognized, which were formed from 0.9MaB.P. to 0.1MaB.P. and showed a close correspondence to the loess paleosol sequences and the oxygen isotope records in deep sea.