Geological Characteristics And Tectonic Significance Of Ophiolite Melange Belt In The Xinlin And Tayuan

The Xinlin-Tayuan ophiolitic mélange zone is located in the northern part of the Greater Xing'an Mountains. The tectonic position belongs to the eastern section of the Central Asian orogenic belt and was considered to be the collision suture zone between Ergun and Xing'an blocks. However, recent studies have shown that there is some controversy over the existence of Precambrian basement in the Xing'an block. Based on the field investigation, this paper collects the data of the predecessors to carry out the comprehensive research work, which is considered to be plate collision or arc-land collision suture zone. The material composition is complex and the tectonic movement is strong..They are composed of the Rock mass and matrix from different times and different sources.The Oregon group and ophiolite in the area are the important components of this belt.The minimum peak ages of U-Pb isotopic ages of 453.2 ± 6.4 Ma and 454.7 ± 3.0 Ma of the sandstone detrital zircons is obtained from the Borelgen Group. The U-Pb isotopic age of the U-Pb isotope is 480.3 ± 3.0 Ma, and the LA-ICP-MS zircon U-Pb isotopic age of 430 ± 4.6 Ma. Initially determined for the Lower Ordovician- Lower Silurian. Based on the field investigation, by the study of rock geochemistry and isotope geology, it is proposed that the lherzolites in the upper reaches of the Xikandoti River are part of the Xinlin ophiolite belt. It is confirmed that there is a north-east-oriented Late Ordovician-Middle Silurian magmatic magmatic belt in the northwest of the Duobaoshan island arc, and its spatial distribution overlaps with the Xinlin ophiolite, the isotopic age is 443-432 Ma. The formation age of the Xinlin ophiolite is tentatively determined in Late Ordovician- Middle Silurian.It is confirmed that the Xinlin ophiolite tectonic rock assemblage has the characteristics of sequence ophiolite and tectonic cold emplacement, and the geochemical characteristics belong to E-MORB, which is enrichment type extended ridge fragment. Based on the spatial and temporal distribution of the island arc,The point that the tectonic setting of the Taoyuan- Xinlin ophiolite belt formed is the arc basin is proposed.