| 潮流场对渤、黄、东海陆架底质分布的控制作用 |
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| 引用本文： | 朱玉荣.潮流场对渤、黄、东海陆架底质分布的控制作用[J].海洋地质与第四纪地质,2001,21(2):7-13. |
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| 作者姓名： | 朱玉荣 |
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| 作者单位： | 中国科学院海洋研究所, |
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| 基金项目： | 国家自然科学基金!资助项目 ( 4 98760 18)，中国博士后科学基金!资助项目 |
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| 摘 要： | 运用二维潮流数学模型，模拟了渤、黄、东海陆架的M2潮汐、潮流。结果表明，渤、黄、东海陆架的潮流有强弱之分以及往复流和旋转汉之别。在此基础上，计算了8种粒径沙的湖平均悬移输沙率、潮平均推移输沙以及相应的输沙率散度。根据输沙率散度的正负，划分了海底冲刷区与淤积区。根据不同粒径泥沙输沙率散度的相对大小，确定出海底的主要底质类型为砂质沉积、粉砂质泥沉积和以粉砂为主的混合沉积。计算结果表明，海底3种主要底负类型的分布格局与海底的冲淤格局以及与输沙率矢量的发散和聚合状况基本一致。在渤、黄、东海陆架，沙脊主要在强往复流区形成，沙席主要在强或较强的旋转流区形成，泥质沉积主要在弱潮流区形成。砂质沉积、泥质沉积以及混合沉积这3种主要底质类型并非孤立存在，而是受渤、黄、东海陆架潮流场控制而形成的一个完整的潮流沉积体系。渤、黄、东海陆架的砂质沉积与泥质沉积并非残留沉积，而是潮流沉积。在没有冷涡的情况下，黄、东海陆架的典型泥质沉积在弱潮流环境中同样可以形成，因此，认为冷涡并非黄、东海陆架典型泥质沉积形成的必要条件。
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| 关 键 词： | 底质分布 潮流 沉积动力学 渤海 黄海 东海 大陆架 |
| 文章编号： | 0256-1492(2001)02-0007-07 |
THE CONTROLLING ROLE OF TIDAL CURRENT REGIME IN THE DISTRIBUTION PATTERNS OF BOTTOM SEDIMENTS IN THE CONTINENTAL SHELVES OF THE BOHAI SEA,YELLOW SEA AND EAST CHINA SEA |
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| ZHU,Yu,rong.THE CONTROLLING ROLE OF TIDAL CURRENT REGIME IN THE DISTRIBUTION PATTERNS OF BOTTOM SEDIMENTS IN THE CONTINENTAL SHELVES OF THE BOHAI SEA,YELLOW SEA AND EAST CHINA SEA[J].Marine Geology & Quaternary Geology,2001,21(2):7-13. |
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| Authors: | ZHU Yu rong |
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| Abstract: | The bottom sediment types in the Bohai Sea,Yellow Sea and East China Sea are diversified,and their distribution patterns very complicated.However,the bottom sediment types can be simplified to be sandy,clayey and mixed sediments with complicated distribution patterns.The continental shelves of the three seas are broad and with shallow water depth, and tidal currents are permanent and dominant in the marine dynamics in the seas.Based on numerical simulation of the tidal currents,the rates of suspended load transport and bed load transport during a single tidal cycle for sediments of 8 different grain size ranges are calculated.The results show that any sediment,whose threshold velocity is less than that of tidal current,has the same transport trend.Suspended load transport rate,bed load transport rate,and the ratio of the former to the latter decrease with grain size becoming coarser and coarser.The erosion/accretion patterns of sediments in different grain sizes are determined by the sediment transport rate divergences,and the results show that the patterns are the same for sediments in different grain sizes.The three main bottom sediment types,i.e.sandy sediment(mainly composed of fine sand),clayey sediment(mainly composed of silty clay)and mixed sediment(mainly composed of fine sand,silt and clay),are obtained by computation.The three bottom sediment types and their distribution patterns are consistent not only with sediment transport field and the sea bed erosion/accretion pattern obtained from simulation,but also with field data of bottom sediment types and divisions.In the seas,sand ridges mainly form in the areas with strong rectilinear tidal currents,sand sheets mainly form in the areas dominated by strong rotatory tidal currents,and clayey sediments,i.e.mud patches,mainly form in the areas with weak tidal currents.Hence,not only the sandy sediments but also the clayey sediments in the seas are formed under the control of the whole tidal current field.The three main bottom sediment types are not separated from each other.In fact,they constitute a whole tidal depositional system.Under the condition with no cyclonic cold eddy,the clayey sediments can form in weak tidal current environments.Therefore,cold eddy is not necessary for the deposition of clayey sediments. |
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| Keywords: | bottom sediment tidal current sediment transport sediment dynamics the Bohai Sea Yellow Sea and East China Sea |
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