The Neogene Constructed And Magma Evolution Of The South Of The Qinghai-tibet Plateau

The use of 1/25 million District tune,1/5 million tune/mine,the relevant scientific research report,published papers,dissertations and mentor team nearly 20years accumulated research area chronology and petrochemical data,in the study area Based on the qualitative test of petrochemical data of the main elemental rocks,the petrochemical type determination and TTG and high-Mg rock assemblage identification are carried out on the neo-related magmatic rocks.Then,from the perspective of the characteristics of rock assemblage and its evolution,The tectonic magma evolution,the following basic understanding.?1?N₁ rock assemblage characteristics:the collision continues to develop,with the plateau uplift energy dissipation,the Miocene stage magmatism is very extensive,GG combination is widely distributed in the Gangdise belt and the Himalayan belt,along the tectonic magma belt edge and center Distribution,there are different levels of vacuum remelting,and Lhasa,Menba,Shigatse,Longzi North,Luozha,Xia,such as local areas for the deep remelting products,showing TT+GG combination characteristics,superficial,shell,mantle material Mixed,is the construction of important copper,lead and zinc polymetallic ore mine area background.The upper crust is extensive and the intensity of the decompression remelting,resulting in extensive research area but sporadic magma emplacement,may be accompanied by W,Sn and three dilute metal mineralization.?2?N₂ rock assemblage characteristics:The GG assemblage of the Upper Miocene is mainly distributed in the Shanxi Triangle and Yadong areas of Shenzha-Rikaze-Nianqingtanggula,while the TT+GG combination is only distributed in the eastern part of Shenzhan and Yadong.With the continuous development of the collision,the extensive and multi-level decompression and remelting effect caused by the uplift and energy dissipation of the Qinghai-Tibet Plateau gradually subsided,and the range of the vacuum remelting was sharply shrinking to Shenza-Rikaze-Nianqingtanggula Shanxi Triangle and Yadong Melting level generally shallow,only in the Shenzhan South East and Asia East area to keep deep melting state.?3?The understanding of tectonic magmatic evolution:combined with petrochemical characteristics,TTG combination characteristics,magmatic activity characteristics and tectonic background:?1?The Sino-Singapore Indian-Asian plate continental crust strong collision,crustal shortening,the region wide deformation of the case,the Himalayan The thickness of the crust is 15¹8km,and the crust is thickened.The crust is thickened and the Gangdese zone is in the north and south.The tectonic setting of the east and the west is extensively developed.A large number of large-scale overturning faults and a large number of north-Barrier structure,and magma activity is strong.The Himalayan belt is in the overbearing orogenic environment,and its forefront is the Sivariik foreland basin.The Himalayan Mountains are the leading edge of the nappe,and the belt is developed with a large number of overlapping tiles.Yelaxiangbo?TT+GG combination?,Xiaru?TT+GG combination?and other nuclear complex,and developed near the north and south to the north and south,and the development of a large amount of metamorphic core complex,?2?The uplift of the Upper Pleistocene Himalayas is still in progress,while the magma activity is weak and in a relatively quiet period,with only a small amount of medium-acid magmatic activity in the Yadong and Medog region of the Greater Himalayas The Yadong granite rock assemblage is TT+GG,which is considered to be a metamorphic core complex.In the Tarma area by the Indian-Asian plate collision squeeze,making the plate within the crust,under the conditions of the basic volcanic eruption.Indicating that the Gangdese zone is still in a collisional extension environment,the Himalayan belt for the napkin orogenic environment.