青海湖第四纪晚期沉积地震地层特征分析

Analysis on the Characteristic of Seismic Stratigraphy of Later Quaternary Sediment in Qinghai Lake

青海湖是我国最大的内陆湖泊,目前的水域面积约4400 km2,流域面积约29660 km2。通过在湖内进行高分辨率浅层剖面探测(GeoPulse),发现不同发育阶段的沉积特征在地震剖面上得到很好的反映。Geopulse高分辨率浅层剖面穿透深度约60 m(分辨率为0.5 m),沉积层序在湖盆中央近水平展布,揭示沉积环境相对稳定,但也有局部的扰动或错断。尤其在南部近岸部位,上表层沉积出现弯曲,说明第四纪的晚近期,青海湖有过新的构造运动。

Qinghai Lake is the largest inland closed-basin lake in China, with an water area of 4 400 km^2 and a drainage area of about 29 660 km^2. Based on the geopulse high resolution sub-bottom profile survey, the later quaternary sediment characteristics in the lake are revealed on the sub-bottom profiles clearly. The penetration and resolution of the sub-bottom profiles are 60 m and 0. 5 m respectively. The profiles in the basin center present a near level sediment stratum that reveals a stable sedimentary envi- ronment of the lake. However, there are also some disturbed sediment layer or small faults in basin boundary, especially, in the south nearshore area of the lake. It suggests that there was neo-tectonic movement in later quaternary in Qinghai lake.