全新世初期地磁极性漂移在南黄海中部泥质区的记录  

RECORD OF GEOMAGNETIC EXCURSION DURING EARLY HOLOCENE IN THE CENTRAL SOUTHERN YELLOW SEA MUD

作　　者：刘建兴[1] 石学法[1] 葛淑兰[1] 李小艳[1] 姚政权[1] 王昕[2,3] 

机构地区：[1]国家海洋局第一海洋研究所,青岛266061 [2]中国科学院海洋研究所,青岛266071 [3]中国科学院研究生院,北京100049

出　　处：《第四纪研究》2012年第4期663-669,共7页Quaternary Sciences

基　　金：国家海洋局908专项新增项目(批准号:908-01-BC15);国家自然科学基金项目(批准号:40710069004和40876036)联合资助

摘　　要：对取自南黄海中部泥质区的NHH01孔进行了高分辨率的古地磁研究,结果显示在4.26～3.84m为一地磁场反极性漂移。结合钻孔在4.59m处和5.69m处的AMS^(14)C测年校正值分别为10200aB.P.和13500aB.P.以及岩芯的沉积特征,认为其在该时段为相对稳定的海相沉积。线性外推该反极性漂移的年限为9470～8540aB.P.,可能是哥德堡反极性漂移在该沉积物中的记录。这就为地磁场在全新世初期发生过漂移提供了一个新的佐证,同时也为该区晚更新世以来地层的进一步精细划分和对比提供了一个标志。The central Southern Yellow Sea mud （CSYSM）had a very high sedimentation rate and a relatively stable sedimentary environment since Holocene,and the sediments are very fine, mainly composed of silt and clay,which are advantageous to record the short polarity excursions during the time. The Core NHH01 （35°13＇N,123°13＇E） which was recovered in 128 drilling cycles（NHH01-1-128） from the CSYSM,with a water depth of 73m and an average recovery rate of 91% in this paper has a whole length of 125.64m. Until now,two AMS14C age data for NHH01 had been gained at the depth of 4.59m and 5.69m,which are 10200aB. P. and 13500aB. P., respectively. We selected the top 5.70m as our researched object,so the NHHO1 in our paper is meant to the 0 -5.70m section of the core. The sediments are mainly clayey silt and sandy silt. A high-resolution paleomagnetic investigation was carried out on the core NHH01 and 270 data of alternating field demagnetization （AFD） were got, from which a reverse polarity excursion between the depth 3.84m and 4. 26m was revealed. To make sure that the reversal was not resulted from disturbance, we then conducted anisotropy of magnetic susceptibility（ AMS） analyses on 10 samples selected from the reverse sect and the results indicated the sedimentation sequence has been unperturbed significantly since deposition. The mean sedimentation rate of NHH01 between 13500aB. P. and 10200aB. P. is 33em/ka and is 45cm/ka since 10200aB. P. An age span of 9200 - 8000aB. P. for the reverse excursion was calculated based on the sedimentation rate of 33cm/ka while 9470-8540aB. P. which is thought to be more rational given that the sedimentary environment since 10200aB. P. has been more stable, based on the rate 45cm/ka. We concluded the reversal may be record of the Gothenburg geomagnetic excursion in this sediment,which provides a new evidence for the occurrence of geomagnetic excursion during the early Holocene and a symbol for further subtle stratigraphic division and correlation of this area

关 键 词：南黄海 NHH01孔 极性漂移 哥德堡 

分 类 号：P318.4[天文地球—固体地球物理学] P736[天文地球—地球物理学]