【摘要】 选择长江南京下关-栖霞山段作为研究河段,根据南京长江大桥、四桥附近的地质钻孔资料,运用Mapin-fo软件,绘制南京长江大桥、四桥附近长江古河槽地质剖面示意图。在拟建南京长江四桥附近的6个钻孔采集了年代样品,在-59.33 m深度上河床相圆砾石层中沉积物样品中有机质的14C年代为14 682±110 aBP,据此判断,位于该沉积层下部的上一期沉积旋回应在15 000 aBP之前。结论认为,该研究河段约-65~-90 m的深槽为末次盛冰期时的长江河槽。古河槽相对狭窄陡峭,形成局部深切。槽中充填了一次从粗到细的沉积旋回。更多还原

【Abstract】 The Xiaguan-Qixia Mountain of Nangjing reach of the Yangtze River was selected as the research reach.Two cross-sections of Paleo-valley depositional sequence were established with respective of bore data and documents of the No.1 and No.4 Nanjing Yangtze River Bridges and by Mapinfo software.Samples were collected from 6 drilling cores near No.4 Nanjing Yangtze River Bridge which is operational,and 14C ages measured in-59.33 m sedimentary samples from No.1 drilling cores is 14 682±110 aB.P.It is deduced that sedimentary cycle in the lower part of the depth occurred before 15 000 aB.P.Therefore,it is discovered that the time range of paleo-valley at a depth of-65～-90 m in Xiaguan-Qixia mountain of Nanjing reach is within the period of LGM.During LGM the deep incised-valley channel was narrow and the river flew swiftly,and expressed locally and deeply which incised features in Nanjing reach.The sediments of the deep incised valley consist of scree and gravel,gravel sand-coarde sand-medium sand from bottom to top.更多还原