浙江三门湾猫头深潭风暴快速沉积研究
Storm rapid sedimentation of Maotou deep trough in the Sanmen Bay of Zhejiang
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摘要: 三门湾频受热带风暴的影响,风暴期出现剧烈的滩冲、槽淤的泥沙交换,而在风暴后的正常天气条件下,则产生滩淤、槽冲的泥沙交换过程.通过猫头深潭(槽)9417号台风前后剖面水深重复测量、沉积特征及沉积物放射性同位素(210Pb,137Cs)测年等资料,揭示猫头深潭风暴快速沉积(骤淤).正常天气条件下风暴沉积产生再悬浮随潮运移,深潭水深得以恢复.在连续强热带风暴的影响下,又遇强的风暴增水,风暴沉积难以完全被冲刷,部分残留在深潭内,在猫头深潭沉积层中储存着风暴沉积的信息Abstract: The Sanmen Bay is frequently influenced by the typhoon,sediment exchange between beach and channel is stronger when storms hit this bay.Tidal currents are forceful with strong bottom current due to the topographic effect and predominantebb occurs in the Maotou Channel.These features of tidal currents are a dynamic foundation to form deeper trough and to keep stability.The seabed is in the equilibrium of erosion and siltation with slight siltation in last 100 a.However,when the storms hit the bay,siltation occurs obviously in the trough and erosion in the broad tidal flat.The sediments which are eroded from tidal flat provide resources for rapid deposit in the Maotou Channel.An average depth of profile across deeper trough reduced about 142 cm measured on August 26,1994,a week after No.9417 typhoon passed the bay.T he data show that siltation streng thens from the slope to the bottom. Then the setting sediment by the storm can be resuspended and removed with the tidal current during normal weather.The depth in the trough is restored with slight erosion measured in January 1995,comparing the depth measured in June 1994.But some years,sedimentation occurred in the Maotou Trough.Three and 4 continued strong tropical storms hit the bay in 1989,1990 respectively,they resulted in storm sediment to retain the trough.It is considered that deposited strata have stored in information of storm sediments in the deeper trough.Some "black mud" layers which contain higher water content,high organic content,low solidity and no-bedding in the undisturbed core are recognized as a rapid deposit retained in the Maotou deeper trough by all previous storms.
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戴贤凯,徐敏.杭州湾深水航道东试挖槽浮泥研究[J].海洋工程,1998,16(2):43~49 LI Jiu-fa. Sediment resuspension and its implication on turbidity maximum in the Changiiang Estuary[J]. Marine Geology,1998, 148:117~124. 夏小明,谢钦春,李炎,等港湾淤泥质潮滩的周期性变化[J].海洋学报,1997,19(4):99~108 中国海湾志编纂委员会中国海湾志(第五分册)[Z]北京:海洋出版社,1991.234~308. 国家气象局台风年鉴(1981~1995)[Z].北京:气象出版社,1982~1996. 蒋建华,谢钦春,夏小明潮流通道边坡潮流垂向结构及其底床冲淤数值模拟[J].泥沙研究,1996,(4):27~33 李贞儒.河道整治工程对断面流速分布的影响[A].中国水利水电工程技术进展[M].北京:海洋出版社,1999 219~222.
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