末次盛冰期长江南京段古河槽特征

CHARACTERISTICS OF NANJING PALEOVALLEY SECTION OF THE YANGTZE RIVER DURING THE LAST GLACIAL MAXIMUM

根据南京长江大桥、三桥、四桥的地质钻孔资料,绘制南京段长江古河槽地质剖面示意图,对拟建南京长江四桥附近的4个钻孔进行了采样分析,从钻孔沉积物样品的14C年代及阶地形成时间可以判断,南京段约-60^-90 m的深槽为末次盛冰期时的长江河槽,钻孔揭示,南京段长江古河槽狭窄陡峭,呈V型,在南京长江大桥附近形成局部深切。

Three cross sections of paleovalley depositional sequences were established based on bore data and documents of Nanjing No. 3 Bridge,the Yangtze River Bridge and Nanjing No. 4 Bridge. Through ^14C dating to samples from 4 drilling cores near the Nanjing No. 4 Bridge which is proposed to construct, it is discovered that the paleovalley at the -60--90m depth near Nanjing existed within the period of last glacial maximum. It is also indicated that the deep incised-valley channel was narrow and the river flowed swiftly. Drilling shows that the valley channel ran deep locally near the Nanjing Yangtze River Bridge,like a “V” shape.