全新世／冰期西赤道太平洋边缘海碳酸钙沉积旋回及其古海洋学意义

CALCIUM CARBONATE CYCLES IN THE MARGINAL SEA OF WESTERN EQUATORIAL PACIFIC AND THEIR PALEO-OCEANOGRAPHIC IMPLICATION DURING HOLOCENE/GLACIATION

本文所研究的区域是西赤道太平洋的两个边缘海盆─—南中国海和苏禄海。分别对南中国海的ＧＧＣ—６孔和苏禄海的ＧＧＣ—２９孔的ＣａＣＯ＿３含量、浮游有孔虫动物群及氧同位素地层进行分析，并用浮游有孔虫转换函数方法对古温度进行分析，用以确定地层年代的气候分期。研究结果表明，本区Ｃａ－ＣＯ＿３旋回模式与太平洋型相反，而与大西洋型一致。即冰期时ＣａＣＯ＿３含量低，全新世冰后期ＣａＣＯ＿３含量高。冰期陆源物质供应的加强是控制本区ＣａＣＯ＿３旋回的主要因素。此外，冰期时南中国海海水溶解作用的加强是控制本区低ＣａＣＯ＿３含量的又一重要因素，而苏禄海受海水溶解作用的影响相对很小。

Two cores,i.e.,the GGC 6 core(12°09′1″E, 118°03′9″N)form the South China Seaand GGC-29 core(8°17′17″E,118°49′9″N) form the Sulu Sea,were studied.Calciumcarbonate, planktonic foraminifera and oxygen isototpe records have been analysed forthe two cores.Basedon these results, we know that the content of calcium carbonate islow in glacial-age sediments and high in Holocene sediments. This is the pattern oppo-site to that of the Pacific. The enhanced terrestrial material offered in the glacial age is amain controlling factor of the CaCO_3 cycles. In addition,foraminiferal dissolution indiceshave been used to determine that the increase in dissolution of the South China Sea is an-other important factor for controlling the low carbonate accumulation and that the disso-lution is weak in the Sulu Sea.