长江口北支中全新世以来的两次环境变异  

TWO ENVIRONMENTAL CHANGES IN THE NORTH BRANCH OF THE YANGTZE RIVER ESTUARY SINCE THE MIDDLE HOLOCENE

作　　者：吉云松[1] 刘苍字[1] 洪雪晴[1] 孙艳梅[1] 

机构地区：[1]华东师范大学地理系,上海200062

出　　处：《海洋地质动态》2003年第3期1-5,共5页Marine Geology Letters

基　　金：国家自然科学基金资助项目 (4 9876 0 2 3)

摘　　要：崇明岛北侧永隆沙钻孔岩心的粒度、环境磁学、微体古生物和1 4 C测年等分析 ,揭示出中全新世以来长江口北支分别在 2 0 80～ 2 0 0 0aBP和 70 0～ 62 5aBP发生过两次环境变异 ,分析认为这是由于气候变化导致长江主泓从北支偏到南支又从南支偏回北支。因此 ,长江三角洲演化的动力系统中 ,在考虑科氏力的同时 ,也不可忽视气候的影响。Analysis of samples obtained from core CY, which lies in the north part of the Chongming Island, shows that at the depths of 5.0～5.4 m and 15.5～16.0 m, grain size composition and magnetic feature of the sediments and foraminifer assemblage change remarkably. These changes were caused by strongly hydrodynamic environment, indicating that the Yangtze River discharged mainly through the north branch during that period. That is to say, in the course of stretching southeastwards, driven by Coriolis force, the Yangtze River estuary may swing back, resulting from the influence of climate.

关 键 词：环境演变 中全新世 长江口 粒度分析 气候变化 

分 类 号：TV148[水利工程—水力学及河流动力学]