长江口与闽浙沿岸泥质区现代沉积记录及其影响因素
DEPOSITIONAL RECORDS IN THE MUD AREAS OF CHANGJIANG ESTUARY AND OFF MIN-ZHE COAST AND THEIR INFLUENCE FACTORS
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摘要: 对东海近岸泥质区16孔与31孔岩心进行了测年和粒度分析,并对其影响因素及所指示的沉积环境变化进行了探讨。结果表明,16孔与31孔岩心的沉积年代分别为49年(1954-2003年)和181年(1822-2003年),平均沉积速率分别是3.27和0.82 cm/a。根据两孔岩心粒度特征,经讨论分析,认为16孔岩心粒度变化主要受长江来沙变化和长江入海主泓位置变化的影响;自1900年之后,31孔岩心粒度变化在一定程度上反映了东亚季风强度的变化。另外,两个岩心中风暴潮和洪水沉积记录与历史资料吻合很好,有利于灾害性事件的研究。Abstract: Dating and grain-size analysis were conducted for the two cores taken at station 16 and 31 in the coastal mud area of the East China Sea. Results show that the mean sedimentation rate is 3.27cm/a for the core 16 during the period of 1954-2003 and 0.8cm/a for the core 31 during the period of 1822-2003. Based on grain-size characters, it is inferred that the sediments of the core 16 is influenced by the shifting of the trunk stream of the Changjiang River and the variation of sediment discharge. And the sediments of core 31 is controlled by the East Asian Monsoon since 1900 AD. The sedimentary records of storm tide and flood are fit well with the history records, that provides a basis for geohazard study.