中文摘要：

青海南山的隆起过程对解析青海湖一共和盆地地区构造地质演化过程具有重要的意义。通过共和盆地西北部晚新生代地层的野外地质调查，发现小水桥剖面上新世地层中存在一期角度不整合面。角度不整合面上覆地层沉积碎屑中含有10％左右的泥灰岩和灰岩，碎屑组成与现代青海南山物质组成基本一致；下伏地层中没有出现碳酸盐岩碎屑。砾岩碎屑成分上的变化显示，上覆地层和下伏地层的源区可能发生了变化。角度不整合面上覆和F伏地层常量元素含量的含量显示，下伏地层CaO平均含量（3．74％）明显低于UCC（4．20％），物源区不太可能有碳酸盐岩存在，而上覆地层CaO平均含量是UCC的2倍多，物源区应该有碳酸盐岩存在。而且，元素比值呈现的上覆地层中不活泼元素（Ti，Si）和活泼元素（Ca）同时“富集”的矛盾，也说明了上覆地层物源区可能有碳酸盐岩的出现。元素之间关系和根据元素含量判定的岩石化学分类等特征在上覆和下伏地层中也有明显的变化。剖面位置现在的物源区就是青海南山，青海南山有一定的碳酸盐岩出露，所以，下伏地层的物源区可能并不是青海南山。结合下伏地层变形特征及区域地质资料推断，上新世青海南山的隆起使其南侧地层倾向西南，并改变了原来的盆地地貌，形成上新世地层顶部的角度不整合面。青海南山形成后才成为两侧盆地的物源区。

英文摘要：

The Nanshan （ Nan Mountain） uplift process is very important in understanding structural evolution of the Qinghai Lake Basin -Gonghe Basin in Qinghai Province. Late Cenozoic sediments are rarely found in natural profile from the east to the west in the Qinghai Lake Basin along Nanshan, but they are common in the Gonghe Basin,especially in its northwestern and northeastern part. The basement of the Gonghe Basin is composed of flysch formation and granite which is assigned to Triassic, upon which the Late Cenozoic sediments are deposited. An angular unconformity was found in the Pliocene stratum during a field exploration in the Xiaoshuiqiao section in northwestern part of the Gonghe Basin and abrupt changes in detrital minerals were detected from its overlying and underlying sediments. The composition of the clast ofthe overlying sediments,with 10%± of limestone and marly limestone,is similar to that of the outcropping along the Nanshan. But clast of limestone and marly limestone does not exist in the underlying sediments, indicating the change of source material. To test this hypothesis, sediment samples were taken for experiments in element content. The average CaO content of the underlying stratum is 3.74%, which is obviously lower than the UCC （4.20%） , showing no carbonate in its source material. However,the average CaO content of the overlying stratum is more than 2 times than the UCC,thus carbonate should be occurred in the source material. Moreover,the element ratio result reveals that both relatively immobile elements（Ti,Si） and high mobile element（Ca） were ＂enriched＂ in the sediments of the overlying stratum, which also suggests that the carbonate should be occurred. Additionally, the adding of Ca is more than its loss in the overlying stratum. In summary, the change of minerals of clast between the overlying and underlying strata has been confirmed not only by major element content, element ration, but also by inter-element relationship and chemical classification of sedimentary roc