摘要: |
二十多年来,渤海湾沿岸的贝壳堤(Chenier ridge)引起了多方面的兴趣,进行过大量的调查研究,论著颇丰。各家讨论的问题比较侧重于贝壳堤的分布和形成年代等方面,并取得了很好的结果。但是,对贝壳堤形成的原因、条件、发育与衰退过程,以及它在渤海湾海岸地貌和沉积层发育中的作用等则很少论及。阐明贝壳堤成因对于海岸沉积、海陆变迁、海滩冲淤、构造运动、海岸水文等方面都有重要的理论意义。
本文通过多年的实际调查研究工作,详细地分析了各贝壳堤的形态和分布、贝壳生物组成、贝壳物质的物理特性、层理结构、层位关系和古海滩面的坡度与物质组成等基本资料,又补充调查了海岸带潮汐沉积、泥沙来源与河流人海口的变迁等资料,着重讨论贝壳堤的成因与发育等问题。 |
关键词: 渤海湾 贝壳堤 |
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基金项目:中国科学院海洋研究所调查研究报告第512号 |
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A PRELIMINORY STUDY OF THE ORIGIN OF THE CHENIER RIDGES OF BOHAI GULF |
Cai Aizhi
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Institute of Oceanology, Academia Sinica
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Abstract: |
On the holocene marine accumulated plain of Bohai Gulf, there are two or more series of chenier ridges. Which have been proved to be relict coastlines of different historical times. Their ages were estimated by C-14 dating and archaeological method:the chenier ridge Ⅱ was formed 3100-3500 years B.P., and the chenier ridge Ⅰ was formed 2000 years B. P.
The chenier ridge consists of molluscan shells and their fragments. The height of the chenier ridge is usually 2-3 m, because of wind action sometimes reaching 6-7 m. Its maximum thickness is 5 m. The width of the chenier ridge is typically 50- 200 m. In estuarine areas, its width is greater.
The following are requisite conditions for the formation of chenier ridges: the beach and shallow are of clayey silt, with a stable slope of 1/100 within the limit of 100 m from the foot of the chenier riage, 1/300 within 100-300 m from its foot seaward, and 1/500-1/600 farther down. |
Key words: CHENIER RIDGES BOHAI GULF |