The Analyses Of Cenozoic Sandstone Component In Northeastern Qaidam Basin And The Study On Relationship Of Tectonic Uplift Event

This paper is studying on Cenozoic formation of northeastern Qaidam Basin in northern Qinghai-Tibet Plateau. Choose Lulehe section which has better outcrop, successive sedimentation and high-precision chronostratigraphy control to analyze sedimentary facies and provenance. The main purpose is provenance analyses, start from the standpoint of sedimentary basin analyses, using clastic constituent method to analyze the provenance in detail and systemic. Identify the tectonic events and its time. In a larger area, Compared with Lulehe section and Changweitai section in west Qaidam Basin. Conclusions are as follows:(1) In Cenozoic there were 8 sets of main sedimentary strata in Qaidam Basin, form bottom to top layer: Eocene Lulehe Formation and Xiagancaigou Formation, Oligocene Shanggancaigou Formation, Miocene Xiayoushashan Formation and Shangyoushashan Formation, Pliocene Shizigou Formation, Pleistocene Qigequan formation and Holocene sedimentary strata. The sedimentary paleoenvironments include alluvial fan,fan delta,lake and river environment.(2) There were a large number of thin gypsum veins in the bottom of the Shanggancaigou Formation of Lulehe section and Changweitai section.This period may be a relatively dry period in the Qaidam Basin. and there were a large number of alluvial fan deposits on the botton of Xiaganchaigou Formation in west Qaidam.(3) During the deposition period of Lulehe Formation, rock debris of Metamorphic stone is dominant in the whole debris, indicating that NanQilian Mountains was the main source area of the northeastern Qaidam Basin at. But during the deposition period of Xiaganchaigou Formation from Shangyoushashan Formation, rock debris of Sedimentary stone is dominant in the whole debris, indicating that Altun Mountains was the main source area of the northeastern Qaidam Basin.Source may hve changed in the period of Xiaganchaigou Formation.(4) Deformation in Northern Qaidam was controlled with Altyn and Qilian Mountains, source may be related with the activities of Altun strike-slip faults, to cause the west section be higher than east section in the northern margin of Qaidam, resulting in source changed in Lulehe section.