东海E_1孔晚更新世以来的地层、生物与环境

Stratigraphy, Biology and Environment of the E1 Core from the East China Sea since Late Pleistocene

东海E1孔水深100m,是迄今东海陆架水深最深、采样最密、研究最详细的钻孔。依据有孔虫动物群的研究和碳同位素测年,可将E1孔的地层分成3段:S_1—S_3(0.00～3.34m)为全新统;S_4—S_(24)(3.34～53.43m)为晚更新统;S_(25)(53.43～55.63m)为中更新统。有孔虫以浮游种类为主,属热带至亚热带动物群。研究发现本区自晚更新世以来有3次高海面期:第一次高海面期与长江三角洲平原的镇江海进、华北平原的天津海进和华南的长乐海进相当,属全新世,为外浅海环境;第二次高海面期与长江三角洲平原的隔湖海进、华北平原的沧州海进、和华南的福州海进相当,属晚更新世晚期,为外浅海环境;第三次高海面期与长江三角洲的江阴海进、华北平原的白洋淀海进相当,属晚更新世早期,为中至外浅海环境。在最晚中更新世低海面期本区曾暴露成陆。

The water depth of the El core from the East China Sea is at 100 meters deep, it is the only one hole of the deepest in water depth, the densest in sampling density, and the most detail in study untill now. Based on the researches of the foraminiferal fauna and the isotopic carbon-14 dating, it has been found that the stratigraphy of the El core can be divided into three phases: A. S1—S3(0. 00 ~3. 34m) fall into Holocene; B. S4—S24(3. 34~53. 43m) belong to late Pleistocene; C. S25(53. 43~55. 63m) is part of middle Pleistocene. The foraminifera are mainly in planktonic species, it belongs to the tropical to subtropical fauna. There were three high sea level periods in this area since late Pleistocene; the first high sea level period corresponds to the Zhengjiang transgression in the Yangtze River delta plain, the Tianjin transgression in North China plain, and the Changle transgression in the South China, it belongs to Holocene and outer neritic environment; the second high sea level period corresponds to the Gehu transgression in the Yangtze River delta plain, the Cangzhou transgression in the North China plain, and the Fuzhou transgression in the South China, it falls into late period of the late Pleistocene and outer neritic sediments; the third high sea level period is corresponding with Jiangyin transgression in the Yangtze River delta plain and the Baiyangdian transgression in the North China plain, it can be classed to the early period of the late Pleistocene and middle to outer neritic province. The marine sediments at the top of the middle Pleistocene, it had been exposed into the land during the low sea level period of the latest middle Pleistocene, it's original environment may fall into inner to middle neritic zone.