近13万年来南沙沉积物中的剩磁记录

REMANENCE MAGNETIC RECORDS FROM RECENT 130 000 YEARS IN SEDIMENTS OF NANSHA AREA,SOUTH CHINA SEA

对长355cm的南沙NS93-5钻孔连续取古地磁样品281块，进行沉积物磁性特征的研究。详细的岩石磁学结果表明，沉积物中以低矫顽磁力的磁性矿物为主，剩磁携带者主要是磁铁矿类矿物，但同时存在少量赤铁矿和磁赤铁矿等。钻孔191～206、232～248和292～308cm记录的剩磁磁倾角出现较小的负值，根据氧同位素地层学和^14C测年、火山灰层年龄，计算其对应的沉积年龄分别为65．87～68．7、73．4～80．8和108．4～113．6kaBP。其中108．4～113．6kaBP的剩磁异常可能是布莱克（Blake）事件在南沙沉积物中的记录。

281 samples, collected from the NS93-5 drilling core located in the Nansha area of South China Sea, were used to study magnetic characteristics of sediments in the Sea. Detailed rock magnetic results show that the magnetic minerals of sediments were dominated by ferrimagnetic minerals such as magnetite, but the small contribution of hematite and maghematite also existed. The sediments recorded three negative values of inclination in 191～206, 232～248 and 292～308 cm. The corresponding age of these negative values are 65.87～68.7, 73.4～80.8 and 108.4～113.6 kaBP according to stratigraphy of oxygen isotope, ^14C and the age of volcano. The negative value during 108.4～113.6 kaBP may be the record of Blake event in the sediments of Nansha area.