The Primary Study Of Geological Features And Tectonic Setting Of Ophiolite In Heishishan Area, Central Qiangtang, Tibet

This paper mainly relies on”The tibet 1:5 million 4 Region survey of ShuangHu area in JiaoMuRi Region”which is taken charge by Professor Wang GenHou of China University of Geosciences (Beijing).Ophiolite on the study area were systematic and comprehensive field observations and laboratory research. Essential to determine the ophiolite in the study area are composed of metamorphic peridotite, cumulate rocks, pillow and stomata basalt and chert. While use geochemical analysis of diagrams to study major elements, REE and trace element of each unit of the ophiolite. In view of the geochemical analysis of diagrams, each units of the ophiolite has a certain Homologous evolution feature.By means of studying the each units of ophiolite and geochemical analysis of graphic and tectonic setting discrimination, we know that the ophiolite of the study area with E-MORE and ocean island (OIB) double feature, combined with the regional Geological background, in the study area with ocean floor basalt and eruption characteristics, combined with Blueschist in this area and eclogites exposed, the authors of the study area is more that the Permian tholeiitic series - alkaline basalt series combination is more likely formed in an ocean island and impacted by the mantle plume.Also, according to the tuffaceous breccia above are pillow basalt with the middle Permian dragonfly fossil, the Ar-Ar age of blue amphibole is 220-223Ma, the Ar-Ar age of eclogite phengite is 217 - 219 Ma, and the emplacement age of collision granite is 210.8±3.8Ma and so on, indicating the ophiolite formation age of the study area is the Permian, and with oceanic crust exists at the Permian - Middle - Late Triassic.