北京平谷地区地表陡坎的成因识别

根据对北京平谷三河地区地表陡坎的观察比较,研究了河流侵蚀陡坎与断层陡坎的微地貌形态差异。河流侵蚀形成陡坎的方向追随河流的冲沟方向,具不稳定性,并且陡坎的倾向沿河对称。断层陡坎的展布不受河流方向的影响,断层以倾向活动为主时,陡坎两盘的运动方向稳定。研究结果表明,平谷地区的地表陡坎是河流侵蚀陡坎。同时,还从构造地貌学与地层沉积学的角度,分析了平原区河流侵蚀沉积与断层断错沉积的特征,指出平谷地区的浅层人工地震探测及浅钻资料存在两种解释的可能性

ON IDENTIFYING THE FORMATION MECHANISM OF SURFACE SCARPS IN PINGGU AREA OF BEIJING

Based on observation and comparison to the surface scarps of the Pinggu-Sanhe area, the mirco-geomorphy differences between the river erosion scarp and fault scarp are studied. Direction of scarps caused by river erosion follows the river, is unstable and the tendency of scarps is symmetric along the river. While distribution of fault scarps is not influenced by the river direction. If the fault is dominated by normal slip, motion direction of both sides of scarps is stable. Study results indicate that the surface scarps of the Pinggu area are river erosion scarps. Characters of river erosion sediment and fault dislocation sediment are analysed from structural geomorphy and stratigrapic sedimentography. It is suggested that there are two possible interpretations for the data of shallow seismic exploration and boring in the Pinggu area.