Detrital Composition,Geochemical Characteristics and Provenance Analysis for the Maerzheng Formation Sandstone in Gerizhuotuo Area,Southern Margin of East Kunlun Region

The sedimentary stratum of Maerzheng Formation is exposed in the Buqingshan Melanges Belt of Southern margin of the East Kunlun region,and it's main part is a set of turbidite of deposition in tectonic setting of passive continental margin of bathyal—abyssal environment.Using analysis of sandstone compositions and geochemical characteristics to explore provenance source rock type and its tectonic setting.The framework composition of the Maerzheng Formation sandstones statistical results show that it's mainly feldspathic litharenite and lower maturity,it's quartz,lithic,feldspar respectively is 44%,21%,37%,the Dickinson diagrams show that provenance is mainly divided from orogenic belt and recycled island arc in category.The geochemical characteristics of sandstones of Maerzheng Formation show that SiO_2 values of 58.12%~72.98%,average value of 67.77%,the REE distributing patterns show rightward incline and weaker negative Eu anomaly,∑LREE/∑HREE=6.5~12.1,δEu=0.63~0.75,the CIA average value of 56 indicates that source rock by primary weathering intensity and have the near source sedimentary characteristics.The results indicate that tectonic setting belong to continental island arc type,the provenance is the volcanic—plutonic magmatic island arc orogene and metamorphic basement of northern East Kunlun block,the sedimentary basin is the trench basin.Consequently,its the important sedimentary response of evolution process of A'nyemaqen—Buqingshan Ocean.