潍坊港临近海域WF01钻孔沉积物磁化率与粒度变化相关性及其物源意义

摘要

本文通过对位于莱州湾南侧、潍坊港东侧近岸海域300 cm长的WF01钻孔进行磁化率和粒度测试,结合测年数据,分析了研究区海域沉积速率、沉积物粒度和磁化率的演化特征,探讨了不同沉积物粒度组分与磁化率变化的相关关系.结果表明:WF01孔0~300 cm沉积物可分为四段,分别体现了不同时期研究区沉积环境的变化.WF01孔以218 cm为界,上段与下段沉积物磁化率与各粒组百分含量的相关关系基本呈相反趋势.上段沉积物磁化率与63 μm以下各组分的百分含量呈负相关关系,与大于63 μm粗颗粒的百分含量呈正相关;下段沉积物磁化率值与小于32 μm各组分的百分含量呈正相关关系,而与大于32 μm的颗粒组分含量呈负相关关系.这种相关性的差异,可以从很大程度上指示研究区上下两段沉积物物质来源的不同,而造成这种物源差异的原因很可能是1855年黄河从苏北改道进入渤海,巨量黄河泥沙在渤海沉积、扩散造成的.%The magnetic susceptibility and grain size of a marine sediment core WF01, located in the east side of Weifang port, were measured and the correlation between them was analyzed.In results, sediments of the drill hole could be divided into four sections, indicating depositional environment change during different periods.The correlation coefficient between magnetic susceptibility and the mean grain size was opposite at 218 cm.The correlation coefficient of magnetic susceptibility with the content below 63 μm was negative, and with the content greater than 63 μm was positive in the depth of 0~218 cm.The correlation coefficient of magnetic susceptibility with the content below 32 μm was positive, and with the content greater than 63 μm was negative in the depth of 218~300 cm.The verschiedenheit indicates the differences of sediments source in the two section, and this was mainly because that the modern Yellow River delta was formed since 1855 when a major switch took place at Tongwaxiang and most suspended load appeared to diffuse and deposit in the Bohai Sea.