南海北部陆坡ZSQD196PC柱状样末次间冰期以来的古海洋学记录:氧同位素、有孔虫和硅藻

PALEOCEANOGRAPHIC RECORDS OF CORE ZSQD196PC FROM THE NORTHERN SOUTH CHINA SEA:OXYGEN ISOTOPE,FORAMINIFERA AND DIATOM

为了解南海北部陆坡末次间冰期以来的古海洋沉积环境演化特征,对研究区ZSQD196PC柱状样有孔虫、硅藻及有孔虫氧同位素资料开展了分析。依据沉积有孔虫、硅藻主要属种的百分含量、丰度及组合特征,将有孔虫划分为3个组合,分别对应于氧同位素MIS1、2、3~4期;将硅藻划分为4个组合,大致对应于MIS1~4期。MIS1期有孔虫以暖水种占优势,Pulleniatina obliquiloculata百分含量显著升高;硅藻丰度低且以热性种占优势,其中冷期出现大量沿岸种,反映相对温暖的气候条件。MIS2~4期有孔虫以冷水种占优势,温跃层种含量相对较高;硅藻丰度高且以广布种占优势,出现沿岸种含量的升高,反映较冷的气候条件。通过对比浮游有孔虫氧同位素,分析讨论了末次盛冰期、Blling—Allerd暖期和新仙女木事件在ZSQD196PC柱状样的沉积响应,揭示了末次冰期中的气候波动。

The environmental evolution in the northern South China Sea since the last interglacial stage was studied by means of the oxygen isotope of planktonic foraminifera,and the paleontology of foraminifera and diatom of the Core ZSQD196PC,which was sampled on a slope in the study sea.According to the percentages of important species,individual amount and assemblage characteristics,3 foraminifera assemblages and 4 diatom assemblages corresponding to the known foraminifera oxygen isotope stages are subdivided.The foraminiferal fauna are dominated by warm-water species in MIS1,and the percentage of Pulleniatina obliquiloculatais significantly high,while the diatom flora are dominated by tropical plankton species.During the period in MIS2~4 stages,the foraminiferal fauna are dominated by cold-water species,and the percentage of thermocline species is relatively high;the diatom flora are dominated by tropical-subtropical plankton and coastal species.According to the comparison to the planktonic foraminiferal oxygen isotope,we discussed the responses of sedimentary environment evolution to the Last Glacial Maximum and the events of Blling-Allerd and Younger Dryas as well as the climate changes during the last glacial stage.