Northern Qaidam Basin Neogene Youshashan With Shizigou Sedimentary Environment And Nature

In this paper, Wulan County in Qinghai Province Sand Willow-Tiger Estuary NeogeneYoushashan, Shizigou group for the study, from the formation of the distribution, petrology,petrography, particle size distribution and other aspects of biological assemblage theNeogene Youshashan, Shizigou conducted a comprehensive study made the followingunderstanding：1. Sand Willow-Tiger mouth area outcropping Neogene strata can be divided into twogroups: group and Youshashan Shizigou. Among them, Youshashan mainly a lacustrinedeposition, but there are also fluvial facies; Shizigou group had no roof, as a lakeside facies.2. Study area Neogene clastic strata coarser to conglomerate, pebbly sandstone, debrispsephicity poor, poor sorting, debris maturity is low, indicating that it is in sedimentary basinedge, away from the object source close.3. The plant fossils found in the work are grown in the lush subtropical forests, reflectingthe basin surrounding the ancient climatic conditions similar to today’s Yangtze River warmand humid climate.4. The work was first found in the lower part there Youshashan calcareous crusts,reflecting lower Youshashan there are several relatively large hiatus, but also illustrates theearly Neogene Lake plane experienced three cyclical movements.5. Within the study area for the Neogene unconformity with the underlying strata is anangular unconformity. And the study area Youshashan can be divided into three sections:section with conglomerate, pebbly coarse sandstone; Sec pebbly sandstone and sandstone;three segments to muddy siltstone, silty mudstone Lord.6. Neogene strata from the area of production location and thickness can be drawn, thelong axis of sedimentary basins north west-south east direction, and the nature of the basinextrusion sag basin.