武都汉林沟流域古滑坡年龄的^(14)C厘定

The Definition of the Ancient Landslide Age with the ^(14)C Dating of Hanlingou River Basin in Wudu

古滑坡一般是指全新世以前地质历史时期发生的滑坡。武都汉林沟流域发育有第四纪晚更新世以来不同时期的滑坡,具有规模大、数量多的特点,为武都白龙江中游滑坡发育历史研究提供了典型实例。通过滑坡体的形貌、结构特征、与其他地层的接触关系分析,确定古滑坡的存在。同时也发现古滑坡曾堵塞汉林沟形成堰塞湖,并压埋了许多古树木,古滑体中残留大量植物遗骸,通过14C测定,进一步确定汉林沟流域古滑坡形成时间为42.0～44.8 ka BP。

The ancient landslides were usually formed in the period of earth evolvement before Holocene. Landslides of Hanlingou River Basin grew well in the different periods during the Epipleistocene and their character-istics present as being on a large scale and in large quantity. It gives several typical examples to study the development of landslides of the middle reach of the Bailongjiang River in Wudu. The ancient landslides grew well by anal-ysis of the topography and characteristics of structure of landslide and contact relations of strata. The research results also show that the water resources from Hanlingou was cut off to form barrier lakes by earthquake and many oldtrees were buried. Now, a large number of the remains of plants remain in the landslides. According to the 14C dating from the root of a tree, the ancient landslides grew about 42.0 -44.8 ka BP.