渭河流域滞留沉积物的磁化率各向异性特征及水动力方向研究

摘要

The magnetic fabric characteristics of stranded deposits were discovered by the research of magnetic susceptibility characteristic on three section(Tianshui,Baoji,Weinan) of Weihe river's upper, middle and lower reaches.stranded deposits is controlled by sedimentation and associated with the sedimentary dynamic of the wei river.Three axis direction and the three axis ratio of stranded deposits magnetic susceptibility is related to space arrangement of stranded deposits magnetic particles.The experimental data from different location sampling of the wei river shows that the average value of L, Q in the the anisotropy of magnetic susceptibility parameters of stranded deposits from the upstream to downstream decreases.But F, P, E, T present the change trend of gradual increase in average value.The anisotropy of magnetic susceptibility characteristic parameters and the orientation of Kmax shows that the change trend of the wei river from upstream to the downstream is mainly hydrodynamic energy waning, stable sedimentary environment, hydrodynamic direction shift from NW to SWW , and same with the wei river flow path.%通过对渭河流域上游、中游及下游的三个剖面(天水、宝鸡、渭南)磁化率各向异性研究,发现了滞留沉积物的磁组构特征.滞留沉积物的形成受控于沉积作用并且与渭河的沉积动力有关,即滞留沉积物磁化率椭球体的三大主轴方向及三轴比值与沉积物磁性颗粒的空间排列分布方式相关.对渭河不同地段取样的实验数据结果得出,上游至下游的滞留沉积物的磁化率各向异性参数中L、Q的平均数值逐渐减小,而F、P、E、T的平均数值呈现逐渐增大的变化趋势.磁化率各向异性参数特征及Kmax的方位表明:渭河上游至下游的变化趋势主要为水动力能量逐渐减弱、沉积环境趋于稳定,水动力方向由NW向转变为SWW向,与现在的渭河水流路径大致相同.