长江三峡非正常含炭粘土沉积及其地质灾害意义

在长江三峡工程库区巫山、奉节、云阳等新县城进行工程地质勘察过程中, 发现在长江岸坡地带存在含炭粘土沉积.对部分含炭粘土进行了14C年龄测定, 年龄测定结果与该含炭粘土层所在高程相当的阶地形成年代不一致, 含炭粘土为非正常沉积.非正常含炭粘土的存在与发现, 一方面揭示出巫山等移民新县城斜坡经历了非正常的形成演化; 另一方面说明长江三峡河谷演化过程中夹杂着突发的地质灾害事件. 

Abnormal Carbonic Clay and Its Significance in Relation to Geological Hazards in the Three Gorges Reservoir Area,Yangtze River

Carbonic clay was discovered on the banks of Yangtze River during geological engineering investigations in the new towns of Wushan,Fengjie and Yunyang counties in the Three Gorges reservoir area,Yangtze River,China.The age of the carbonic clay was estimated by 14C dating.The results indicate that there is a considerable discrepancy in the age of the carbonic clay and the age of the terrace,located at the same altitude.The carbonic clay proves to represent sediment from an abnormal environment.The discovery of the abnormal carbonic clay indicates that the formation and evolution of the slope along the Yangtze River,in immigrant settlement regions(such as Wushan),is abnormal.It also shows that there were outbreaks of geological hazards in the evolutionary history of the Yangtze River valley in the Three Gorges reservoir area.