南沙群岛及其邻近海区第四纪气候演化的非线性特征

南沙群岛及其邻近海区近１８.５万年以来气候与环境非线性研究表明曾发生三次明显气候转变，形成四个映射区。其中氧同位素第５期与第４期转变较明显，其次是氧同位素第６期与第５期的转变，最后是第３与第２期之间的变化，这与全球第四纪古气候研究结果是一致的，得到了氧同位素和古生物资料的进一步印证。半深海－深海海底沉积物有机质演化阶段在海进海退过程中表现出垂直分带和非线性变化。上陆坡以氧化堆积带为主，有机质供给多、但消耗迅速且水动力相对强；中陆坡为利于有机质保存的还原带；下陆坡为有机质缩合阶段，陆坡下缘－远洋为有机质沉降氧化带与沉积埋藏阶段的植烷形成带。这几个带在古气候、古海平面非线性变化中是沿海底向上或向下迁移的，其变化是非线性的。

Non Linear Characteristics of Quaternary Climate Evolution of Nansha Islands and their Adajcent Sea Areas

The non linear mapping results for the latest 185 Ka sediments from the Nansha Islands and adjacent sea area show that they belong to bathyal or abyssal deposits and without tectonic movements' effects.Ns87 8,Ns90 103 and Ns90 102 column core samples deposits in upper continental slope,intermediate slope and downslope, respectively.The paleoclimate non linear mapping research suggests that there are three significent alternations of cold and warm climate for the latest 185Ka,forming four mapping division.The alternation between oxygen isotopic 5th division and 4th division is more important than the alternation between the 6th division and 5th division.The change between 3rd and 2nd oxygen isotopic division is less important than others.This conclusion are compatible with the data for the global paleoclimate.In addition,the organic matter evolution stage are of the vertical zonation and non linear variations in progression and transgression.