The Characteristics Of Cenozoic Sedimentary And Provenance Analysis In The Northern Qaidam Basin

This paper based on the northen margin of Qaidam Basin during Cenozoic Era, and choosing the representative Eboliang Area and Honggouzi Area as the research object on the sedimentary facies of provenance analysis. From the viewpoint of sedimentary basin analysis,For four consecutive sedimentation of Cenozoic strata in these two area in the microscopic identification, detrital component projection, Vertical distribution of debris ingredients,etc. Provenance analysis of the study area, the purpose is to be able to distinguish the provenance, distinguish provenance transition event, and further to identify tectonic events of period of time,.Get the following understanding:(l)Eboliang Aera total outcropped in ganchaigou formation, the oil sands mountain group, the oil sand hill group on three sets of stratum,development of Lacustrine depositional systems.Honggouzi Area total outcropped in ganchaigou formation, the oil sands mountain group, the oil sand hill group,shizigou group on four sets of stratum,development of alluvial fan-lacustrine depositional system.(2)Sandstone component seen under the microscope identified in the study area we can see Quartz with single crystal quartz content is more than polycrystalline quartz; Feldspar are mainly developed Plagioclase and feldspar, Part of the feldspar in alteration of sericite; The lithic are mainly developed metamorphic rock lithic, sedimentary rock lithic, a small amount of magmatic rocks lithic, mainly to the metamorphic quartzite lithic, schist lithic, slate lithic, sandstone lithic.(3)Debris analysis of sandstone composition and vertical distribution figure shows that there are three obvious changes in time, time points:9.5Ma,13.8Ma20.4Ma.By inference these three sections period sediments of the study area is the most abundant time, also the most abundant provenance source supply time and this time is Qaidam Basin response to surrounding Altun Orogenic Belt event changes.(4)About20.4Ma-17Ma Altun occur a tectonic uplift event, about14.9Ma-12.5Ma The Altun occur a second uplift, about9.5Ma-8.3Ma Altun occur a uplift again. Previously studied about20Ma and8Ma, Altun has twice uplift.Therefore,this article identifies20.4Ma-17Ma and9.5Ma-8.3Ma two times periods for the Altun occurred in20Ma and8Ma of two tectonic uplift event also provides a powerful evidence.