大凌河河口地区晚更新世晚期以来的沉积环境演化

Sedimentary environmental evolution of the Dalinghe Estuary area since the Late Pleistocene

对大凌河河口地区ZK3钻孔(孔深36.7m)岩心开展粒度分析、AMS14C年代测定、有孔虫鉴定分析等综合研究,同时结合该地区5口工程钻孔的岩心以及部分测年资料,初步建立了大凌河河口地区晚更新世晚期以来典型的地层序列格架和时空对比框架,揭示该地区晚更新世晚期以来河道-湖沼-滨海/河口湾-浅海-三角洲的沉积演化过程。研究结果表明:大凌河河口地区在8 500cal a BP前后开始接受海相沉积,并约在4 000cal a BP之后进入三角洲沉积阶段;晚更新世晚期以来的海平面变化是大凌河河口沉积演化和沉积环境演变的主要控制因素;大凌河对现代辽河三角洲的形成和演化过程可能有较重要的影响。

A shallow drilling（ZK3）of 36.7mlong was accomplished for the comprehensive studies on granulometric analysis,AMS14 C dating,foraminifera analysis in the Dalinghe estuary area.Combining with the data from five other engineering drillings,a typical stratigraphical sequence and a time-space comparison framework are roughly established for the estuary since the Late Pleistocene,showing sedimentary evolutions from fluvial to limnetic to littoral/estuarine to shallow sea and then to deltaic environments in this area.This study reveals that marine environments began to prevail in the Dalinghe Estuary area at about 8 500 cal a BP,and evolved into deltaic one after4 000 cal a BP;the sea level changes since the Late Pleistocene was the main factor controlling the sedimentation and environmental evolutions in the Dalinghe Estuary;Dalinghe may plays an important role for the development and evolution of the modern Liaohe Delta.