长江三角洲NB5孔第四纪地层划分及环境变化信息  

Stratigraphic division of NB5 core in the Yangtze delta area and its environmental change information

作　　者：缪卫东[1] 李世杰[2] 冯金顺[1] 高立[1] 鄂建[1] MIAO Wei-dong;LI Shi-jie;FEN Jin-shun;GAO Li;E Jian(Geological Survey of Jiangsu Province, Nanjing 210049, Jiangsu, China;Institute of Geochemistry Chinese Academy of Sciences, Guiyang 550002, Guizhou, China)

机构地区：[1]江苏省地质调查研究院,江苏南京210049 [2]中科院地球化学研究所,贵州贵阳550002

出　　处：《中国地质》2016年第6期2022-2035,共14页Geology in China

基　　金：中国地质调查局项目(GZH201200506)资助~~

摘　　要：长江三角洲北翼NB5孔做了古地磁测试、^(14)C测试及ESR测试结果,对古地磁变化特征进行了总结分析,结合区内其他钻孔的对比,对钻孔第四纪地层划分及所反映的古气候环境进行了探讨。结果表明:46 m处为全新世底界,163 m为中更新世顶部,240 m左右为早更新世顶部,354 m为早更新世底部。其中,海相层有2个,位置在2~47m,125~163 m。分别对应于Ⅰ(Qh)镇江海侵,Ⅲ(Q_p^(3-1))昆山海侵。据晚更新世以后沉积物粒度变粗及磁化率所反映的巨大变化特征,提出中更新世晚期、晚更新世初期为长江主泓流经本区的时间,并认为此或与塑造中国现代地貌的共和运动造成的青藏高原再次强烈隆升有关。Located in the west beach of Pacific Ocean and the mouth area of Yangtze River, the Yangtze delta area is doubly affectedby the sea and the regional big river. Therefore, the sedimentary environment is very complex. The NB5 hole is in the north ofYangtze delta area. The NB5 hole at Xiting Town of Nantong City was drilled 362 m deep with 354m thickness of Quaternary strata.According to testing results of paleomagnetism, 14C and ESR of NB5 core, analyzing the lithological character, and a comparisonwith other cores in this area or nearby areas, the strata were divided and the environment evolution since the Quaternary wasinvestigated. The result indicates that the bottom of Holocence is at about 46 m, the top of middle Pleistocene is at about 163 m, thetop of lower Pleistocene is at about 240 m, and the bottom of lower Pleistocene is at about 354 m. There are five marine face layersin the core which are located 2- 47m and 125- 163 m. they are the 1st transgression layer (Zhenjiang transgression) and the 3rdtransgression layer (Kunshan transgression), because there exist remarkable different lithological characteristics and magnetic susceptibilities above 163 m and below 163 m in the core. The authors hold that the Gonghe movement that occurred in late middlePleistocene might have affected the environment of this area greatly so that the main river flowed through this area.

关 键 词：长江三角洲 NB5孔 古地磁 第四纪地层划分 环境变化 

分 类 号：P534.63[天文地球—第四纪地质学]