【摘要】 对中国黄土标准剖面———洛川黄土剖面之下的上新世红黏土进行了沉积特征和磁性地层学的研究,结果表明洛川红黏土堆积于约2.6~3.2 MaBP期间,从而确定世界惟一的黄土类地质公园的风尘开始堆积的年代约为3.2 MaBP。古气候替代性指标磁化率和粒度的分析表明,洛川风尘堆积序列记录了上新世到第四纪古气候的重大转型。更多还原

【Abstract】 In this work,the’Red Clay’deposit underlying the typical loess-paleosol sequence at Luochuan,central Chinese Loess Plateau,is studied on magnetostratigraphy,grain size distribution and magnetic susceptibility.It shows that aeolian deposit of the late Cenozoic at Luochuan,the National Loess Park,started at least since 3.2 Ma before present.Proxy index of paleoclimate of this aeolian sequence such as grain size distribution and magnetic susceptibility indicates that the paleoclimate was relatively warmer and less varied during the late Pliocene than that of the loess deposit during the Quaternary period and there was a significant climate shifting that took place around 2.6 MaBP,the boundary of the Pliocene and Pleistocene in North China.更多还原