南极鲍威尔海盆D4-9柱样古地磁及磁组构特征

为了探讨中更新世以来南极半岛东北部鲍威尔海盆沉积环境气候演变及古流向特征，对采自南极半岛东北部鲍威尔海盆内一根3m长柱样进行了古地磁和磁组构参数测试和特征分析。结果表明：1）该柱样在2.73m处为布容正极性与松山反极性期的界线，由此推算出在距今780ka到现代该区域沉积速率较低，约为0.35cm/ka。2）中更新世以来该区域共出现过5次暖沉积事件，并且在暖期事件中存在3次明显的冷期气候波动事件。3）该区域在暖期古流向方向不明显，水流方向变化频繁，而在暖期之间的过渡时期，古流向以近似南北向为主。

PALEOMAGNETIC CHARACTERISTICS OF ACORE FROM THEPOWELL BASIN,ANTARCTIC PENINSULA

One 3 meters long gravity core was obtained in Powell basin, which located in the northeast of Antarctic peninsula, and then the AMS (Anisotropy of Magnetic Susceptibility) and paleomagnetism data was acquired through analysis by KLY-3s and 2G superconducting magnetometer. An remarkable plus inclination stage was identified in the depth of 2.73m, which should be in accord with the Matsuyama reversed polarity time, from which we calculated that the sedimentation rate is 0.35cm/ka from now to BP.780ka. At the same time, 5 warm climate periods were identified by the analysis ofmagnetic susceptibility andgrain size characteristics in this core, and there are 3 obvious gradual climate transitionstages between warn periods, which changed from warm to cold, and then from cold to warm. From the analysis of maximum axis angle of AMS, we found thatthepaleocurrentdirectionwas not obvious in thewarm period,the flow directionchanged frequently,but the paleocurrent directionapproximatedto north or south in thetransitionperiod between thewarm periods.