石英尾砂对濠河中、下游沉积物磁学性质的影响及其环境意义

Magnetic influence of Quartz tail-sands on sediments in the middle and lower reaches of the Haohe River and its environmental implications

为监测石英尾砂对濠河沉积物的影响,采用环境磁学方法进行研究.在濠河中、下游采集了三条典型沉积物剖面,通过详细的岩石磁学参数与SiO_2质量分数(w(SiO_2))测量,结果表明濠河中、下游沉积物中的主要磁性矿物是磁铁矿.三条典型沉积物剖面在纵向上按磁性参数曲线的变化特征均可分成四个磁性层,第二、第三、第四层沉积物受石英尾砂稀释作用的影响显著,W(SiO_2)的平均值高达80%,这三层沉积物的磁学性质由石英尾砂控制.濠河中、下游沉积物的磁性参数(χ、SIRM和χ_(ARM))随w(SiO_2)增加而减少,两者存在负相关关系(-0.88≤R≤-0.81),表明磁性参数可用于分析石英尾砂对濠河沉积物的影响.同时,沉积物磁性参数的变化也能指示沉积环境的变化.

To monitor environmental influences of quartz tail-sands on sediments around the Haohe River, mineral magnetic parameters and SiO2 content （w（SiO2）） were measured on three representative sedimental in the middle and lower reaches of the Haohe River. The results show that the main magnetic mineral in the sediments was magnetite. These three representative sedimentary sections can be divided into four sub-layers. The second, the third and the fourth middle and lower reaches of the Haohe River decreased with increasing w negative correlation （--0.88≤R≤-0.81） between the concentration o SiO2 content. Therefore, we concluded that magnetic parameters can influences of quartz tail-sands on sediments. Meanwhile, variations parameters might indicate changes of the depositional environment.