The Discovery of the Unconformity on Upper Carboniferous in the Southern Qiaerlong,Akto County,Xinjiang

During 15 million regional geological survey,the authors found that there was a unconformity at the top of Keying group in Qiaerlongnan.The unconformity was manifested as the paleo-weathering crust,basal conglomerate,sequence missing and strata chemical abnormal.The study shows,for sea level relative decline in Sinian-Devonian,it is caused by sedimentary interruption in sedimentary facies evolution-coastal-neritic phase to sedimentary basin.That reflects the unconformity's sxistent by data of measured sections,geological mapping,chemical strata and paleo-geographic framework.The discovery has important significance of elucidating sequence stratigraphic framework and evolution of paleogeography in carboniferous,west Kunlun,and denies the statement about regional fault with predecessors.