中文摘要：

选择位于南沙台地的NS93-5钻孔进行地磁场相对强度的研究。根据氧同位素地层学（MIS1～MIS5），建立130ka以来的沉积序列。岩石磁场研究表明，沉积物中的磁性矿物主要为1—15μm的细粒磁铁矿，磁性矿物浓度的变化在同一数量级之内，而且沉积物磁性比较稳定。选择NRM／X作为相对磁场强度的估计指标，发现在10-100ka时间尺度上，可以很好地进行全球对比，千年时间尺度上尽管有一定的误差，但也可以进行有效对比。130ka以来，有4次强度变化的低谷，分别发生在32．5—40ka、44—52．5ka、66．5-70ka和100-109．5ka。其中32．5—40ka和100～109．5ka两次强度的低值可能分别记录了Laschamp事件和Blake事件。这种高分辨率的地球磁场相对强度的全球可对比性，为全球高频气候和环境变化的研究提供了一种可选的年代对比框架。

英文摘要：

Piston core NS93-5, located in the south of the South China Sea, is selected to study the relative paleogeomagnetic intensity. Based On oxygen isotope data （ MIS1 - MIS5 ）, augmented by radiocarbon age and pozzuolana age, the age model of core is established. Rock magnetic results show that the fine magnetite （ 1 - 15 μm） dominates in the sediments, and the concentration of magnetic minerals are at the same scale. NRM/x, take as an index of relative geomagnetic intensity, shows the longer wavelength （10 - 100 ka ） features that Can be compared with global documents effectively. Prominent low paleointensity occurred at 32.5 -40 ka, 44 - 52.5 ka,66.5 - 70ka and 100 - 109.5 ka which also canbe found in other areas. The low valUes at 32.5 -40 kaand 100- 109.5 ka represent the Laschamp event and Blake event respectively. The records are attributable, in large part, to the globalscale field, and therefore have potential for inter-hemispheric correlation at a high-resolution scale.