长江北翼古河间台地全新世海岸环境变迁

发布时间：2018-01-25 21:37

本文关键词： 长江三角洲北翼古河间台地全新世浅海相粉(细)砂滩　出处：《海洋湖沼通报》2016年05期 　论文类型：期刊论文

【摘要】：本研究获取了位于长江三角洲北翼吕四外古残留台地之上的SR11孔,通过对该孔上部22.2m地层粒度、磁化率、有孔虫属种和14 C年代的研究,重建了该河间台地全新世海岸环境变迁历史。结合辐射沙洲核部其他钻孔资料,本研究认为:末次盛冰期北坎和三余之间古长江支谷与干流河谷之间存在残留的谷间台地,向东向南延伸至吕四外的潮滩及近滨地带。9—5cal ka BP期间,吕四外的残留河间台地主要处于浅海环境,但部分时段频繁受到风暴活动影响。该阶段后期,海平面上升速率减缓,台地演化至潮下带下部环境。5cal ka BP以后,海平面上升到-3m以上,台地逐渐演化到潮间带下部-潮下带上部的粉(细)砂滩环境。吕四外残留台地之上的全新统地层中未发现潮流沙脊相沉积。
[Abstract]:In this study, the SR11 hole located on the Lusiwai paleoresidual platform in the northern wing of the Yangtze River Delta was obtained. The granularity, magnetic susceptibility, foraminifera species and 14C age of the upper part of the hole were studied. The history of the Holocene coastal environmental change of the Hejian platform was reconstructed, and other borehole data of the radiative sandbar core were combined. In this study, it is concluded that there are residual intervalley platforms between the paleo-Yangtze River branch valley and the main stream valley between the last glacial peak period and the northern ridge and more than three years. During the period of eastward and southward extension to the tidal flat outside Lusi and near the littoral zone .9-5cal ka BP, the residual interriver platform of Lusiwai is mainly located in the shallow sea environment. However, in some periods, it is frequently affected by storm activity. In the latter stage, the rising rate of sea level slows down, and the sea level rises above -3m after the platform evolves to the environment of .5cal ka BP in the lower part of the subtidal zone. The platform gradually evolves to the silt (fine) sand beach environment in the lower part of the intertidal zone and the subtidal zone.
【作者单位】：广东财经大学地理与旅游学院;中国科学院南海海洋研究所中国科学院边缘海重点实验室;
【基金】：教育部人文社会科学研究青年基金项目(14YJCZH145) 国家自然科学基金青年基金项目(41306047)资助
【分类号】：P736.22
【正文快照】： 引言自20世纪70年代大范围地质调查的开始,长江三角洲第四纪沉积环境演化一直是我国地学研究的热点问题之一。以李从先为代表的众多学者对长江三角洲晚第四纪层序地层的研究首先识别出了全新世长江三角洲演化的一个重要模式——河口沙坝-汊道体系[1-2]。另外一方面的进展主要

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