【摘要】 大别山北麓竹竿河黄土—古土壤样品的磁组构特征显示,研究剖面0～1480cm层段的平均Pj、F值小于1.02,而底部Pj、F大于1.02。F—L、Pj—q组合关系图反映磁化率椭球体为压扁状,磁面理较磁线理发育。磁化率椭球体主轴方位显示0～1480cm层段样品的椭球体轴向分布分散,长轴的倾角大于60°,短轴的倾角小于15°,而底部的分布聚集,长轴的倾角一般小于10°,短轴的倾角大于80°,上述特征综合揭示了0～1480cm层段属于典型风成沉积而底部属于典型水成沉积。磁化率椭球体最大主轴的偏角暗示风成沉积的主导风向为NW—SE方向,而水成沉积的古流向为SW—NE方向,与现代竹竿河水系的方向基本一致。磁化率各向异性最大轴方向的优选方向可能与大别山抬升等构造运动有关。更多还原

【Abstract】 The magnetic fabric parameters of the Zhuganhe loess—palaeosols profile on the northern slope of the Dabie Mountains show that the mean values (Pj<1.02,F<1.02) of the upper (0~1480cm) strata is less than that of the bottom. F—L and Pj—q plots of the samples very clearly indicate that the samples have oblate ellipsoids fabric,and the magnetic foliations are dominant over magnetic lineations. Stereographic projection of anisotropy of aximum magnetic principal axis shows that the direction of declination of the upper strata is relatively dispersing with inclination of the long axis smaller than 15°and short axis bigger than 60°, however,the bottom is relatively concentrating with inclination of the long axis smaller than 10°and short axis bigger than 80°;Generally, magnetic fabric characters show that the upper strata is aeolian deposit and the bottom is hydraulic deposit. The stereographic projections of the K1 and K3 demonstrate that the wind direction in the comparatively upper strata is NW—SE, While the direction of water flowing in the bottom strata section is SW—NE,which is corresponding to the trend of the Zhugan River, the K1 optimal directions of AMS may be controlled by the uplift of the Dabie Mountains.更多还原