摘要
金沙江上游新构造运动活跃,崩塌、滑坡、堰塞湖等地质灾害广泛发育,是古、今堰塞湖多发的地区.以金沙江上游雪隆囊大型古滑坡堰塞湖溃坝堆积物为例,对溃坝堆积物的粒度特征及其与沉积环境的关系进行了研究.并对雪隆囊滑坡堰塞湖溃坝堆积物的粒度进行了测试.结果表明:1)从溃坝堆积体的上段→中段→下段,粒度频率曲线分别为单峰、多峰、双峰,粒径有明显的细化趋势(粗→细);2)溃坝堆积物的分选系数从上段→中段→下段依次减小,表明分选性逐渐变好;3)溃坝堆积物的粒度累积曲线上游段为两段式,中、下游段为三段式,水动力条件从上段→中段→下段依次减弱.以上这些特点综合反映了该研究区内水动力条件由溃坝堆积体上游到下游在逐渐减弱.
Active Neotectonic movement in the upper reaches of the Jinsha River,collapse,landslide,lake dammed and other geological disasters are widely developed in ancient and modern eras. In this paper,the sedi-ments caused by outburst of Xuelongnang Lake,a barrier lake in the upper reaches of Jinsha River,is taken as an example to study the grain size features and sedimentary environment. The grain size of the sediments was test-ed and analyzed by the methods of indoor particle size screening and sedimentation method. The results show：（1）The grain size frequency curves of the upper,middle and lower segments of the accumulation body resulted from dam break,have single peak,multi peaks and double peaks,with the grain size having an obvious thining tendency;（2）The sorting coefficient of the dam break accumulation decreases from the upper segment to the middle segment and then to the lower segment,showing that the sorting gradually becomes gentle;（3）The dam break accumulation curve has two sections in the upstream segment and three sections in the middle and lower segments. Hydrodynamic condition is weakening gradually from the upper to the middle and then to the lower segments. The grain size features of the sediments reflect a sedimentary environment of rapid accumulation and under strong hydrodynamic conditions.
出处
《冰川冻土》
CSCD
北大核心
2016年第2期509-516,共8页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(41571012)
中央高校基本科研业务费专项(2652015060)资助
关键词
雪隆囊
粒度参数
频率曲线
累积曲线
Xuelongnang Lake
grain size parameter
frequency curve
cumulative curve
