摘要
通过对位于浙—闽沿岸泥质带的EC2005孔岩性、粒度以及AMS14C年代分析,探讨了研究区自末次冰消期以来的古沉积环境演化,认为是湖水或海水深度、气候变化等综合影响的结果。岩芯底部60.20～41.00m(17.3～13.1ka BP)为湖泊三角洲沉积序列,可划分为前三角洲—三角洲前缘—三角洲平原三个沉积亚相,物质来源主要是湖盆流域物质的输入。随着海平面的逐渐上升,海水自13.1ka BP开始侵入研究区,形成了41.00m的海相沉积地层,可划分为前滨—近滨—浅海三个沉积亚相,与海平面变化曲线具有良好的对应。自12.3ka BP开始,研究区受到沿岸流影响,长江物质开始影响研究区,7.3ka BP以来主要是来自长江的悬浮体在沿岸流作用下输送沉积而形成,稳定的泥质沉积物开始形成。全球性重要气候事件如新仙女木事件、8.2ka冷事件在东海内陆架沉积物中也得到了良好揭示。
Based upon analysis of lithology, grain-size and AMS^14C dating for Core EC2005, located in the mud area off the Zhejiang-Fujian coast in the inner shelf of the East China Sea, the paleoenvironmental evolution can be ascertained. The hydrodynamic conditions and sedimentary environment changed greatly which could have been an integrated result of the varieties of lacustrine water depth, sea-level and climatic changes. From the bottom 60.20 m to 41.00 m （ 17.3 - 13.1 ka BP） , a lacustrine delta developed, which can be divided into three facies ： prodelta, delta front and delta plain. The delta sediments are dedueed to mainly from the local drainage area. The sea water arrived at the study area at 13.1 ka BP and a 41 m thick sediment formed from then on, which can be divided into three facies： foreshore, nearshore and shallow sea. The facies evolution was well corresponding to the sea level changes, the hydrodynamic conditions changed greatly also during this period. From 12.3 ka BP, the study area was influenced by Zhejiang-Fujian Coastal Current （ZFCC）, and Yangtze-derived materials had been transported southward from that time. Since 7.3 ka BP, the sedimentary environment is dominated by the ZFCC, and the homogeneous mud sedimentation began to form. The worldwide climatic events such as the Younger Dryas episode and the 8.2 ka event were well recorded in the core.
出处
《沉积学报》
CAS
CSCD
北大核心
2009年第1期118-127,共10页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目(批准号:40576032,40776030)资助
关键词
古环境
末次冰消期
粒度
东海内陆架
EC2005孔
paleoenvironment, Last Deglaciation, grain-size, inner shelf of the East China Sea, Core EC2005
