Stable isotope record of planktonic foraminifera of ODP Hole 117-723A

Oxygen and carbon isotopic analyses have been performed on the tests of Globigerina bulloides, Globigerinoides sacculifer, Neogloboquadrina dutertrei and Pulleniatina obliquiloculata to study the Delta delta18O and Delta delta13C of shallow and deeper depth living planktic foraminifera species. High and low Delta delta18Oobl-bul and Delta delta13Csac-dut coincides respectively with the low and high flux of G. bulloides (established monsoon upwelling index). The tangible relationships between the flux of G. bulloides and oxygen and carbon isotope differences between the shallow and deeper depth habitat planktic foraminiferal species appear to suggest that Delta delta18O and Delta delta13C of surface and subsurface living foraminifera can be used as isotope indices of upwelling in the Arabian Sea.本研究针对布氏抱球虫（Globigerina bulloides）、袋拟抱球虫（Globigerinoides sacculifer）、杜氏新抱球虫（Neogloboquadrina dutertrei）与斜室普林虫（Pulleniatina obliquiloculata）的壳体开展氧碳同位素分析，旨在探究栖息于浅部与深部水体的浮游有孔虫（planktic foraminifera）类群的Δδ¹⁸O与Δδ¹³C特征。Δδ¹⁸O_obl-bul的高值与Δδ¹³C_sac-dut的低值，分别对应布氏抱球虫沉积通量（已确立的季风上升流指数）的低值与高值。布氏抱球虫沉积通量与不同栖息水层浮游有孔虫的碳、氧同位素差值之间存在显著相关性，这表明栖息于表层与次表层水体的有孔虫的Δδ¹⁸O与Δδ¹³C，可作为阿拉伯海上升流活动的同位素替代指标。