青藏高原盆地系统演化与高原形成时间

青藏高原在以时间为坐标的隆升过程中,高原的范围、高度都是呈阶段性递增的.随着青藏高原的构造隆升,在高原的内部和外围发育了众多的沉积盆地,在这些沉积盆地中详细地记录了青藏高原的隆升过程.高原北部盆地的演化显示出向北递进增长的特征,以南北挤压为动力背景的北部前陆盆地演化代表了盆地对高原周缘造山带的响应关系:金沙江缝合带、昆仑山、祁连山的新生代逆冲抬升的时间分别为53 Ma、46 Ma和29.5 Ma.对高原南北盆地-造山带的构造演化对比发现:祁连山和高喜马拉雅的逆冲时间相同,说明青藏高原在渐新世基本定型.

Basin system evolution and formation time of Qinghai-Tibet Plateau

The uplifting range and altitude of the Qinghai-Tibet plateau is increasing by stages. Many basins appear and develop while the Qinghai-Tibet plateau uplifts, and the basins have recorded the details of the plateau uplifting. The study of the basin record shows that the basin-and-range is the growth form of the Qinghai-Tibet plateau towards the north and the orogeny is the form of the plateau growth towards the south by stages at Cenozoic. The foreland basins are the direct responding result of orogenetic action in the north of the Qinghai-Tibet Plateau and formed at dynamic background of north-southward extruding and shortening. The foreland basins in the north of Qinghai-Tibet Plateau have the following evolution time sequence: 53~23 Ma in Hoh Xil foreland basin, 46~2.45 Ma in Qaidam foreland basin, 29.5~(0.13) Ma in Jiuquan foreland basin. Corresponding foreland basins in the north of the Qinghai-Tibet Plateau are the orogenetic thrusting and uplifting: 53 Ma in Jinshajiang suture belt, 46 Ma in Kunlunshan orogenic belt and 29.5 Ma in Qilianshan orogenic belt. The contrast of the evolution between the northern and southern basins of the Qinghai-Tibet Plateau shows that the Qilianshan belt and high Himalaya belt have the same time of thrusting. The range of the Qinghai-Tibet Plateau basically formed 30 Ma before present.