The Geoehemical Fcaturcs And Protolith Restoration Of Beizhen City Graphite Mine In Liaoning Province

Beizhen region locates in western Liaoning platform subside of Yanshan platform subside belt and in the east wing of the Yiwulu mountain anticline in the north China platform. East next to lower Liao river basin, in the control of YaolugouJinxi and Jinzhou- Haertao crust fracture in east west orientation & the ductile shear belt in north west orientation. The visible structures in Beizhen region is given priority to fracture structure and anticline fold. Stratum is composed of Dayingzi and Waziyu series, Jianping group, archean erathem; Dahongyu and Gaoyuzhuang series, Great Wall group, mesoproterozoic erathem; quaternary strata, cenozoic erathem. Deteriorated Archean and Mesozoic volcanic rocks are mainly Magmatic rocks.The exposed rocks in region mainly are Carbonaceous killas, limited griotte and transitional killas with the granite magmatism, which belong to the lower metamorphic rock series inthe regional metamorphic rocks. Due to different degree of metamorphism and deformation, it’s difficult to confirm protolith construction only via field rock assemblage and petrographic characteristics for Beizhen regional metamorphic rock series. Therefore, this article chose some representative samples for analysis.Through the analysis of the data percentage characteristics of the whole rock in Beizhen region, we calculate the ratios, DF values, Nigel eigenvalues of key elements, draw related diagrams to distinguish the original rock types.Through the F1-F2 source discriminant function diagram of clastic sediment rock and ω(La)/ω(Th)-ω(Hf)/10-6 source discrimination diagram, we analyze the provenance and tectonic background of the original rocks.Finally, we work out the following conclusions via the above methods:1. The main rock types in Beizhen area, Liaoning provinceof are carbonaceous killas, griotte, etc., micas and feldspars are main minerals.We can obviously see directional arrangement of minerals under the mirror.It says the influence of extrusion or stretching in a certain period of time.2. According to the rock chemical compositions characteristics & relevant datas in Beizhen area,we speculate that the original rock in Beizhen region are sedimentary rocks or intermediate-acid volcanic rocks.3.Zircon SHRIMP analysis showed that the ages concentrated in the paleoproterozoic and lower jurassic, This states that they are associated with the old metamorphic basement of paleoproterozoic, it reflects graphite sedimentary metamorphic process in Beizhen region.4. According to geochemical datas and related graphic of protolith restoration in Beizhen region,we judge the rocks in the research area are parametamorphites, means the original rock is sedimentary rock, mainly such as clay rocks, argillaceous sandstone, feldspathic sandstone, source components are given priority to quartz-feldspathic, quartzose rocks. And it contains igneous source and recycling old sediment. Although metamorphic rocks in the research area formed in the passive continental margin environment, they inherited source geochemical information of earlier active continental margin and island arc basin,This declares the region is evolved from active continental island arc to passive margin gradually.