下辽河平原和辽东半岛海岸带晚更新世以来的海侵

本文根据钻孔资料、¹⁴C测年数据、微体古生物及孢粉组合特征,讨论了研究区晚更新世以来海侵的次数、规模、时间以及岸线变化。

A STUDY OF THE TRANSGRESSION PROCESS SINCE LATE PLEISTOCENE ON THE COAST ZONE OF LOWER LIAOHE RIVER PLAIN AND THE LIAODONG PENINSULA

According to core, 14C dating, faunas and sporo-pollen assemblage, this paper approaches to this area's transgression process since Late Pleistocene from frequence, scale, time, marine facies stratigraphic characteristics and the changes of coast line.On Lower Liaohe River Plain, transgression has happened three times since Late Pleistocene, the first two times, separately happening 110000-70000 years ago and 40000-30000 years ago, were not broad in scale. In this period, sea water intruded along river mouths and fractures. Holocene transgression, the broadest in scale, started 10000-9000 years ago.6000-5000 years ago,sea water intruded inland 50-60 km. But along the Liaodong Peninsula, only Holocene transgression was remarkable. On the eastern coast of the peninsula, transgression started 11000-10000 years ago. Sea water came to or near the highest level 8000-6500 years ago, when sea water intruded inland 10-20 km.submerging valley and plain.6000-5000 years ago, sea water level began to drop.In the regression process there were at least three periods,separately 45000-4000 years ago, 3000 years ago and 2400-1500 years ago, when sea leval variation temporarily stopped and coast line was relatively stable. In these stable periods, barrier, bar, spit and berm were formed along the shore.At present, along Lower Liaohe River Plain and mud coast on the easterr Liaodong Peninsula except some area on Xiaolin River mouth and the eastern side of Liaohe River mouth,seabeach due to continued supply, are expanded and coast line goes forward to the sea.