南京仙林地区中更新统红色粘土的磁性地层学特征

南京地区第四纪地层广泛发育,主要为上更新统下蜀组及以上地层,其下中更新统地层未见成型剖面。在南京地区三维地质调查中,钻探发现在典型的上更新统下蜀组黄土之下有一套红色含砾粘土层,经对该孔磁性组构、磁化率等测试及研究,认为该红色粘土与长江中下游普遍发育的网纹红土时代相当。其顶底界线清楚,地层完整,岩性独特,为全面认识南京地区中更新统地层提供了重要证据。

Magnetism stratigraphy of middle Pleistocene red clay in Xianlin area,Nanjing City

Quaternary stratum is extensively developed in Nanjing,which consists of Xiashu formation of upper Pleistocene and its above strata.The standard section of Middle Pleistocene stratum reported before has not been discovered.A set of red clay bed with gravels below the Xiashu formation of upper Pleistocene was found in Xianlin area,Nanjing city.The test result of magnetism fabrics and magnetization rate shows the set of red clay bed is consistent with net-shape red clay bed that is distributed widely in the middle and lower reaches of Yangtze River.Its upper and bottom dividing lines are clear,the stratum is completely developed,and soil property is unusual.All of these characteristics provide some information for understanding Middle Pleistocene stratum in Nanjing area.