An analysis of sediments characteristics of Early-Middle Triassic Longwuhe Formation from Guomaying area in Guinan County, Qinghai Province

Longwuhe Formation of Guomaying area in Guinan County of Qinghai Province is a typical set of turbidity current deposits, Previous knowledge of its sedimentary environment is not sufficient. The authors studied turbidite sedimentary characteristics through the analysis of rock assemblage characteristics, sequence stratigraphic sequence and Bouma characteristics of turbidite from Longwuhe Formation of Guomaying area, and discussed the characteristics of sedimentary environment in comparison with typical turbidite fan pattern so as to establish a sedimentary model. Comprehensive analysis shows that the three sections of Longwuhe Formation are located in the outer fan, middle fan, and inner fan of turbidite fan in upward succession. A lot of watercourses are developed in the middle fan. The study of the sedimentary environment and tectonic evolution has the vital significance for the investigation of the West Qinling orogenic belt.