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叶城晚新生代山前盆地的岩性主要由中新世的细粒泥岩和砂岩 (乌恰群 ) ,上新世的砂岩夹薄层砾岩 (阿图什组 )及上新世—更新世的粗粒砾岩 (西域组 )构成。中新世的沉积以细颗粒泥砂岩为主 ,表明物源区较远 ,古流域坡度较小 ,搬运距离较长。古流向分析显示物源区位于南和偏南方 ,此时昆仑山的地势起伏尚不大。到上新世的阿图什组沉积时 ,开始出现砾石沉积 ,反映西昆仑山已经开始有规模地隆升。西域砾岩的沉积标志着作为物源区的西昆仑山已有相当的高度 ,随着山系的隆升 ,基底岩石被暴露和剥蚀。
The lithology of the Late Cenozoic piedmont basin in Yecheng is mainly composed of the Miocene fine-grained mudstone and sandstone (Wuqiaqun), the Pliocene sandstone-clastic thin conglomerate (Atushi Formation) and the Pliocene-Renewal The world’s coarse conglomerate (Western Formation) composition. The deposition of the Miocene is dominated by fine-grained siltstone, indicating that the source area is farther away, the slope of the paleo-drainage basin is smaller, and the transport distance is longer. Paleo-flow analysis shows that the provenance area is located in the south and south, at this time the undulating terrain of the Kunlun Mountains is not large. When it came to sedimentation in the Atushi group of the Pliocene, gravel deposition began to occur, reflecting that the West Kunlun Mountains had begun to scale up. The deposition of conglomerate in the western region indicates that the West Kunlun Mountains, as a provenance area, have reached a considerable height. As the mountain system rises, the basement rocks are exposed and eroded.