TECTONIC AND SEDIMENTARY EVOLUTION OF BASINS IN THE NORTH OF -TIBET PLATEAU AND NORTHWARD GROWING PROCESS OF QINGHAI-TIBET PLATEAU

Abstract

In the north of Qinghai-Tibet plateau from Hoh Xil basin to Hexi Corridor basin, geomorphy hasbasin-ridgestructure, which is the result of long-term geological process of uplift and increase in Qinghai-Tibet plateau. Some of geological evolution process in Qinghai-Tibet plateau and wererecorded in corresponding basins. By the research of sedimentary filling pattern and dynamic background at Cenozoic in Hoh Xil basin, Qaidam basin and Jiuquan basin, we can find that evolution sequences of these three basins are similar: strike-slip basin or extensional basin at the early stage, foreland basin at the middle stage, intermontane basin at the end. Foreland basins are the direct responding result of orogenetic action in the north of Qinghai-Tibet plateau, which were forming at dynamic background of north-southward extruding and shortening. Foreland basins in north of Qinghai-Tibet Plateau have the following evolution time sequencing: 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. This evolution time sequencing and process proves that north part of Qinghai-Tibet plateau grew northward by stages atCenozoic.