江苏大丰中潮滩大小潮周期沉积特征研究

Sedimentary characteristics of spring-neap tidal cycles on middle tidal flat in Dafeng, Jiangsu Province, China

于2007年7月28日至8月14日期间对江苏大丰海岸中潮滩进行了连续半个月的大小潮周期沉积的现场观测与采样,对采集的沉积物样品在室内进行了粒度、沉积通量和质量磁化率等的测试,结果表明:研究区中潮滩沉积物颗粒的粗细、沉积通量等与潮汐的周期变化关系不明显,而与波浪之间有着较为密切的关系;从中潮滩的上部到中部,再到下部,沉积物颗粒由细变粗,沉积通量由低变高,质量磁化率由小变大。此外,研究区的中潮滩沉积物质量磁化率与粒径组分中的细砂和极细砂关系密切。本项研究结果为微观尺度上潮滩沉积差异的分析以及潮汐韵律层作为高分辨率测年工具的适用性评价提供了参考。

From 28th of July to 14th of August 2007, in-situ observation of the sedimentary characteristics of mid- dle tidal flat was carried out in the central Jiangsu province, China. During this period, sedimentary samples were collected after each high-tide period （day or night）. Particle size, sediment flux and magnetic susceptibility of the samples were measured in the laboratory. The results show that the particle size of middle tidal flat sediments and sediment flux are closely related to the wave, not tidal cycle. From the upper of the middle tidal flat to the lower, the sediment particles become coarser, the sedimentary flux becomes larger and quality susceptibility turns into greater. In addition, the magnetic susceptibility of middle tidal flat sediments has a close connection with fine sand （2φ-3φ） and very fine sand （3φ-4φ）. These results can provide references to the analysis of differences of tidal sedimentation in micro-scale and the reliability assessment of the age-dating method with tidal rhythmites.