浙闽沿岸泥质潮滩沉积磁性特征及其物源判别

潮滩沉积的物源一直是沉积学领域重要的研究内容。近30年长江入海泥沙量持续减少，致使长江入海泥沙对浙闽潮滩沉积的物质贡献降低。在此背景下，探究浙闽沿岸潮滩沉积的物源具有重要的现实意义。对杭州湾至福州湾沿岸的泥质潮滩表层沉积开展了详细地磁学研究，结果显示，研究区沉积物的磁性主要受磁铁矿主导，但磁性矿物含量、磁畴和矫顽力等磁性特征存在一定差异，这可能意味着沉积物受到多物源影响。皮尔森相关性分析进一步表明，沉积物磁性特征受粒度效应影响有限，主要与物源差异有关。物源判别结果指示，浙闽泥质潮滩沉积的物源包括长江、海岸基岩和浙闽河流。杭州湾至福宁湾，沉积物普遍受到长江和浙江诸河混合物质的影响，且浙江诸河的物质贡献较大；隘顽湾和象山港沉积物还受到其附近海岸基岩的影响；福宁湾沉积物可能还受到闽江源物质和其附近海岸基岩的影响；罗源湾和福州湾沉积物的潜在物源是闽江和其附近海岸基岩，长江和浙江诸河的物质贡献相当有限。

Sedimentary Magnetic Characteristics and Provenance Identification of Muddy Tidal Flats Along the Coast of Zhejiang and Fujian

Tidal flats are one of most vital regions in the world. In the Zhejiang and Fujian Coastal regions， the tidal flat is the most important reserved land resource. Research on the provenance of tidal flat sediment along the coast of Zhejiang and Fujian is an important source for managing the land resource. In the past 30 years， it has been observed that the tidal flat sediment in the area originates from the Yangtze River. As the flux of suspended matter declines， its contribution to the Zhejiang and Fujian tidal flats is continuously decreasing. In this study， exploring the provenance of the tidal flats has important practical significance. In order to clarify the provenance of muddy tidal deposits along the coast of Zhejiang and Fujian， 154 muddy tidal flat surface samples are collected from Qiantang River to Minjiang River. Simultaneously， the suspended matter from 12 rivers is sampled from corresponding rivers as well as the Yangtze. Particle size analysis and detailed magnetic studies were carried out on these samples， which include isothermal three-axis stepwise alternating demagnetization， thermomagnetic analysis， magnetic susceptibility parameter， remanence parameter and coercive force parameter. The results show that the magnetic properties of the sediment in the study area are dominated by magnetite； there are differences in the magnetic mineral content， magnetic domains and coercivity among the sediment， which may mean that the sediment are affected by multiple sources； Pearson correlation analysis confirms that the magnetic characteristics of the sediment are basically independent of the grain size， and it is mainly related to the difference of the provenance. The provenance identification results indicate that the provenance of the mud tidal flats in Zhejiang and Fujian include the Yangtze River， coastal bedrock， and Zhejiang and Fujian Rivers. From Hangzhou Bay to Funing Bay， the sediment is generally affected by the mixed material of the Yangtze River and Zhejiang rivers， and the material from the Zhejiang rivers is relatively large. Among them， the sediment of Aiwan Bay and Xiangshan Bay is also affected by the coastal bedrock material， and the sediment of Funing Bay may be additionally influenced by the Minjiang River and coastal bedrock materials. The sediment in Luoyuan Bay and Minjiang Estuary may mainly originate from the Minjiang River， and the coastal bedrock material also has a certain influence on it.