石羊河古终端湖泊沉积物粒度特征与沉积环境初探

利用石羊河古终端湖泊野麻湖剖面沉积物的粒度资料，分析了粒度组成、粒度参数、概率累积曲线等粒度特征，并探讨了古终端湖泊的沉积环境．结果表明石羊河古终端湖曾经是一个稳定的湖泊环境，大约在距今４０００多年前演变成为浅湖沼环境，现在已完全干涸．野麻湖剖面记录的数层快速风成沉积代表了周期性的沙尘暴事件．

Preliminary Study on Grain Size Characteristics of Sediments and Depositional Environment of Palaeo terminal Lake of Shiyang River

The grain size characteristics of Lake Yema sediment, part of palaeo terminal lake of Shiyang River, are analyzed in this paper, including grain size distribution, grain size parameters, probability cumulative curve of grain size. The results indicate that the palaeo terminal lake of Shiyang River had been a steady inland lake, but grew to be a shallow lake or bog about 4000 years ago, and has dried recently. During the evolution of the palaeo terminal lake, aeolian silt and sand was an important pattern of Lake Yema sediments. Moreover, Lake Yema has documented many rapid aeolian transports and depositions, indicating periodical extreme dust storm events.