西沙海槽末次盛冰期以来钙质超微化石特征及古海洋学意义  

CALCAREOUS NANNOFOSSILS AND ITS PALEO-OCEANOGRAPHIC IMPLICATION IN THE XISHA TROUGH SINCE THE LAST DEGLACIAL MAXIMUM

作　　者：段虓 陈芳[1] 庄畅[1] 张欣[1] 

机构地区：[1]国土资源部海底矿产资源重点实验室、广州海洋地质调查局,广州510075

出　　处：《海洋地质与第四纪地质》2014年第5期89-94,共6页Marine Geology & Quaternary Geology

基　　金：国家专项课题(GZH2011003050602)

摘　　要：通过对南海北部西沙海槽XH-27PC柱状样钙质超微化石丰度和组合的分析,并结合浮游有孔虫氧同位素分析、碳酸钙含量测定,讨论了末次盛冰期以来古环境和古海洋的变化。超微化石丰度、属种组合变化指示了末次冰期本区受陆源物输入的影响较大,冰后期则主要受开阔大洋的影响。受陆源营养物质输入的影响,根据F.profunda百分含量估算的表层海水初级生产力具有末次冰期高、冰后期低的特征。钙质超微化石的溶解作用在冰后期较强、末次冰期较弱,表现出"太平洋型"旋回特征,与碳酸钙含量的"大西洋型"旋回不同。The changes in calcareous nannofossils and composition abundances have been studied for the piston core 27A from the Xisha Trough, South China Sea, and planktonic foraminifera oxygen isotopes and calcium carbonate have also been analyzed. The result shows that the 805 cm-long core contains a depos tional history since the marine isotope stage2（MIS2）. Sedimentary column of the core can be divided into three parts： 660~805 cm interval of the last glacial maximum, 465~660 cm interval of the last deglacia tion time and 0~465 cm of post-glacial time in Holocene. The study area was influenced by the continent during the last glacial time, whereas by the open ocean during the postglacial time. The primary productivi- ty was higher in the glacial time and lower in the Holocene converted by Florisphaera profunda content. During the glacial time, the dissolution of calcareous nannofossils was stronger than that in Holocene, with characteristic of ＂Pacific type＂ of carbonate cycle, while the carbonate content shows a pattern of ＂Atlantic type＂ of cycle.

关 键 词：钙质超微化石 晚第四纪 西沙海槽 南海 

分 类 号：P736.22[天文地球—海洋地质]