The Characteristic Of Magmatism And Tectonic Significance In The Region Of Huangshuitang,Xichang,Sichuan

The region tectonic Of Huangshuitang is complex.Our predecessors make a large amount of research work in this area,and have a detailed deduction on the cause of the Panxi rift and tectonic periods.However,the formation and dead time of the Panxi rift valley still have considerable controversy.The author tried to get rid of complex tectonic history,and emphasis on the Huangshuitang,s regional tectonic geology and the volcanic rock,sedimentary rocks and metamorphic rocks at this period in detail,to describe the characteristics of regional tectonic evolution at each period.This article which relies on the project of national geological survey,based on the mineral petrology,geochemistry and zircon age,and also collects the relevant data and research.We establish the research object on Zali Formation,Su Xiong Formation,Emeishan Basalt Formation and the same period,s intrusive rocks.Through the carding and search of geochemical,we definite magmatic tectonic evolution in the workspace,and divide three tectonic-magmatic cycle such as jinning,chengjiang,variscan-indosinian.The volcanic rock of Zali Formation is the main research subject at Paleoproterozoic period.It is located on the west side of Anling river fault,around Dechang country.Regional tectonic controls the distribution of Zali Formation.Its occurrence is residual and sporadic,in granites belong to Nanhua Period or Triassic.The lithology is relatively single,mainly the coarsest amphibolite.Nanhua Period extrusive rock mainly occurs in Su Xiong Formation,and see a small amount of volcanic clastic rock in Kaijianqiao Formation.Those rocks are mainly distributed betweet the east of Anling River fault and the middle of Luoji Mountain.The type of rock is relatively single,mainly in the form of rhyolite-dacite and pyroclastic rock.A small number of Altered basalt is found in the Su Xiong Formation at the west of Anning River fault zone.During the same period,the intrusive rocks are distributed in the west of the Anning River,and the lithologic types are more complex,including diorite,granodiorite,monzogranite Et al.Permian rock is distributed in the west of Anling River,sporadic intrusion along granite rock belong to Nanhua Period,also devoured by Triassic granites.Comprehensive analysis Indicate that basic volcanic rocks in Luliang-jinning period,with the Zali Formation amphibolite plagioclase rock group as the research object,is under the regional gathering structure system of local extensional environment,formed by partial melting depleted mantle weak alkaline from the basaltic eruption.It is the product of the tectonic environment of the volcanic effect of the ocean-continent collision.Chengjiang period granite mainly is at the background of Rodinia cracking stage,these are mostly made up with A and I-type granite.The geochemical characteristics of Permian rock is the same as the Emei basalt rock,belongs to the product of continental intraplate environment,and synchronous granite is formed Triassic period and product of mantle-derived late magma evolution.