上海长江口南岸第四纪钻孔微体古生物化石分布特征及其沉积环境指示意义  

Distribution of microfossils record in Quaternary sediments and its environmental significance in the south bank of the Yangtze Estuary

作　　者：郑磊[1] ZHENG Lei(Shanghai Institute of Geological Survey,Shanghai 200072,China)

机构地区：[1]上海市地质调查研究院,上海200072

出　　处：《上海国土资源》2022年第4期1-7,共7页Shanghai Land & Resources

基　　金：中国地质调查局地调项目“长三角1:5万环境地质调查”。

摘　　要：有孔虫和介形虫是有效的古环境研究指标,对指示海侵强度、恢复古环境和相对海平面变化具有重要意义。本文对长江口南岸第四纪钻孔(LDZ1)沉积物的粒度、年龄和微体古生物化石分布特征进行了研究分析。结果表明,LDZ1孔50 m以下无有孔虫和介形虫分布,指示了河湖相的冲积平原环境,而孔深50 m以上则经历了三角洲—河口湾—三角洲的环境演替。微体古生物分布特征显示孔深39.47~50.00 m、24.00~33.00 m和4.00~14.00 m存在3次海侵事件,并以第2海侵层海相性最强,推测在孔深30.60 m处存在一次海平面快速上升事件。On the basis of analysis of age, grain size, foraminifera and ostracoda distributions from the quaternary core LDZ1 in the Yangtze River delta, the present study discusses the palaeo environment and sea level change. Results demonstrate that no microfossils were found blow 50 m indicating a fluvial-lacustrine system. Foraminifera and ostracoda distributions show a deltaic-estuarine-deltaic system above 50 m. There transgression events were detected at core depth 9.47-50.00 m, 24.00-33.00 m and 4.00-14.00 m, and the second transgression was the strongest one. Additionally, the dominant microfauna species indicate an abrupt sea level rise at core depth 30.60 m.

关 键 词：第四纪地质 沉积环境 微体古生物 有孔虫 介形虫 海侵事件 

分 类 号：P534.63[天文地球—第四纪地质学]