摘要
本文依据辽东半岛东部海岸堆积地貌分布、晚第四纪沉积层序与时代,以及沉积物中所含贝类、微体古生物和孢粉化石等资料,分析了晚第四纪海水进退对沉积环境演变及海岸形成与发育的影响,以及现代海岸的淤长趋势,指出全新世海侵前本区海岸曾为山前洪积-冲积平原,7000—6000年前海侵时海岸沿河谷平原内伸5—15km,并形成了沿岸丘陵低地上高8—10m的贝壳堤和海成阶地岸线,近5000年来又形成了三道贝壳堤岸线。
This paper is a detailed study on the late Quaternary sedimentary sequence and environment, Holocene sea-level changes, paleoshoreline ages and migrations, coastal evolutional mechanisms and present evolutional tendency of the eastern coast of Liaodong Peninsula based on the data of field investigation, geological drillings and the analyses of carbon-14 datings, sporo-pol-lens, microfossils, etc., of the sediments.The data available show that during the low sea-level stage of the Wurm Glacial Period in late Pleistocene Epoch, the coastal lowland in the study area was a terrestrial sedimentary environment in which stream deposition and lacustrine-bog sedimentation were the dominant geologic processes. Holocene transgression reached its climax at about 6 200 years B. P. when sea level was 5-6 metres above present mean sea level. Sea level began to fall at about 4 700 years B. P., In the regression process, the stand still sea-level occurred 4 times in 4 500-4 000 years B. P., about 3 000 years B. P., 2 000-1 500 years B. P., and the past 1 000 years B. P. respectively.The lower and middle Holocene transgressive sequence of the eastern coastal zone of Liaodong Peninsula consists mainly of depositions of nearshore shallow-water facies and marine-terrestrial transitional facies with a thickness of 4-20 m, thinning westwards. The middle-upper Holocene sequence consists mainly of depositions of lacustrine and fresh-water swamp facies and river facies. Now the shoreline of the muddy coast between the Yalu River Mouth and the Dengsha River Mouth advances seawards at a speed of 50 m/a, and the intertidal flat silts up with a depositional rate of about 5 cm/a.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
1989年第3期252-262,共11页
Oceanologia Et Limnologia Sinica
