全新世以来苏北平原古地理环境演变

CHANGES OF THE PALAEOGEOGRAPHIC ENVIRONMENT IN NORTH JIANGSU PLAINS SINCE THE HOLOCENE

本文研究了全新世以来苏北平原古地理环境的演变过程。结果指出:晚更新世,海面下降,本区为陆地环境。在早全新世及中全新世期间,全世界气候转暖,海面迅速上升,本区发生海侵,东部成为一片浅海。其后,海面缓慢下降,本区发育了古砂堤群,并形成了南、北两大泻湖区。晚全新世,因黄河夺淮,大量泥沙带至里下河及硕项一桑墟和艾塘泻湖区,古泻湖被淡化,最终淤积为平原。东部海岸线迅速东迁,形成了黄淮三角洲与滨海平原。

This article deals with the course of the changes of the Palaeogeographic environment in North Jiangsu plains since the Holocene. The results are summarized as follows. In the late Pleistocene, this district remained as land when the sea level lowered. During the early and middle Holocene when the climate of the whole world became warmer, the sea level rose rapidly and, followed by transgression of sea, the east part of this region was reduced into a shallow sea. After that, the sea level declined slowly and a group of the old sand bars took shape and two lagoons were formed in the northern and southern areas. During the late Holoeene, a great quantity of sand was carried into the Lixiahe lagoon and the Shuoxiang-shangxu, Aitang lagoons due to the Huanghe River occupying the Huaihe River. The old lagoons were freshened and finally they were silted up to become plains. The east part of the coastline then moved eastward rapidly, forming the seashore plain and the Huanghe-Huaihe River Deltas.