我国在燕山运动后,所形成的山脉遭受风化侵蚀破坏,其风化产物沉积于山前或山间盆地中而成第三纪的红色岩层,其分布极广。此种岩层受水流侵蚀后,造成现今的河谷。第三纪红色岩层的特点是:岩相变化剧烈,尤以山麓及湖盆边缘为甚,所含盐类成分高,胶结疏松。因此这种岩层沉积区易被侵蚀而成盆地,部分亦有保 After the Yanshanian movement in China, the mountains formed were subjected to weathering and erosion damage. The weathering products were deposited in the piedmont or mountain basin as a red rock formation of the Tertiary period, which is widely distributed. This kind of rock is eroded by the current, resulting in today’s valley. Tertiary red rock formation is characterized by dramatic changes in facies, especially in the foothills and edge of the lake basin, which contains high salt content, loose cement. Therefore, the sedimentary area of ​​this rock is easily eroded into a basin and partly protected