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通过对南沙海区 1795 7和 1795 8两柱状样中浮游有孔虫的研究 ,首次揭示了南海晚第四纪以来较长时间尺度上 (0 - 80 0 ka BP)存在 δ1 8O11期 (约 40 0 ka BP)开始的粉红色 Globigerinoides ruber大量出现和 Globigerinarubescens较高相对丰度 ,δ1 8O5 e期 (约 12 0 ka BP)的粉红色 Globigerinoides ruber绝灭 ,Globoquadrina conglomerata大量出现 ,Globorotalia truncatulinoides左旋型分子绝对优势开始 ,和 δ1 8O4/ 5期界线附近 (约 80 ka BP)的 Globo-quadrina conglomerata绝灭等三次浮游有孔虫演化事件。南沙与南海北部及西北太平洋等海区的浮游有孔虫演化事件对比表明 :南沙海区在 40 0 ka BP开始海水温跃层相对较深 ;至 δ1 8O5 e期时 ,受西北太平洋中层水加强的影响、南沙海水温跃层变浅 ;在 δ1 8O5 e至 4/ 5期界线这段时期内与西北太平洋水体交换比较自由
The study of planktonic foraminifera in the two columns of 1795 7 and 1795 8 in the Nansha sea area revealed for the first time that δ 18O11 (about 40 0) occurred on the long time scale (0-80o ka BP) in the South China Sea since the late Quaternary ka BP), and Globigerinarubescens with a relatively high abundance. The pink Globigerinoides ruber of δ1805e (~1200 ka BP) is extinct, the Globoquadina conglomerata is abundant, and the absolute dominant position of Globorotalia truncatulinoides And the extinction of Globo-quadrina conglomerata near the boundary line of δ18O4 / 5 (about 80 ka BP). Comparisons of the evolution of planktonic foraminifera from the Nansha to the north of the South China Sea and the northwestern Pacific Ocean show that the sea thermocline is relatively deep from 40 ka BP in the Nansha sea area and is affected by the intensification of the middle water in the Northwest Pacific Ocean , And the thermocline of the Nansha sea water becomes shallower; during the period of δ1805e to 4/5, it is relatively free to exchange water with the Northwest Pacific Ocean