| 瓯江溺谷海湾充填成陆和河口湾的形成过程 |
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| 引用本文： | 祝永康.瓯江溺谷海湾充填成陆和河口湾的形成过程[J].地理学报,1993,48(3):254-261. |
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| 作者姓名： | 祝永康 |
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| 作者单位： | 杭州大学 杭州310028 |
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| 摘 要： | 利用钻孔、考古以及文献资料,结合河口输沙的研究和河口演变的若干特点,提出了在溺谷型海湾的基础上,河口湾的形成演变和成陆过程。
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| 关 键 词： | 河口湾 充填模式 成陆过程 海湾 |
FORMATION AND FILLING UP OF OUJIANG RIVER ESTUARY IN ZHEJING PROVINCE |
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| Zhu Yongkang.FORMATION AND FILLING UP OF OUJIANG RIVER ESTUARY IN ZHEJING PROVINCE[J].Acta Geographica Sinica,1993,48(3):254-261. |
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| Authors: | Zhu Yongkang |
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| Abstract: | Based on the analysis of data from drillings,historical literatures and cultural relics,as well as the research of sediment movement and river mouth changes in the Oujiang River Estuary, thispaper deals with the evolution and the process of filling up of the Oujiang estuary after the last glacial age . Conclusions are drawn as follows:
(l)During early Holocene, because of the falling of sea level, the ancient river mouth mi-grated eastward and was located on the present continental shelf. On the site of the present estu-ary,there was the mountainous fluvial environment.
(2)During mid-Holocene,the sea level rose and gradually reached its present position,and even slightly higher. Thus,transgression took place,resulting in the drowning of the valley and the formation of estuary . An estimation based on the thickness of marine deposits shows that sedi-ments derived from catchment basin made up about 26% of the total filled-up volume of the an-cient drowned estuary, while the marine sediments accounted for about 74% of the volume. Obvi-ously marine sediments were the principal materials which filled up the drowned estuary. These facts indicated the nature of estuary.
(3)Since the mid-Holocene,the formation of estuary and land within it can be divided to four patterns: a) Deposition and land formation in the early stage in the upper head of estuary. The area hence produced made up 20. 7% of the totally formed area ;btransformation of branch estuary into lagoons and freshwater lakes,and artificial reclaimed land. This is the main pattern and the area generated in this way made up about 42% of the total fromed land ;c)Formation of coastal plain by marine fine materials and the artificial reclamation of tidal flats. The area pro-duced in this way made up 26. 7% of the totally formed land ;d)Expansion of sand bars in the main trough of Oujiang River and their mergence into land owing to deposition of materials. |
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| Keywords: | River mouth estuary Sedimentary model Landformation process |
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