西北地质2018，Vol.51Issue(1)：65-76,12.
西藏谢通门县春哲地区中二叠统下拉组硅质岩地球化学特征及构造环境意义
Geochemical Characteristics and Tectonic Environmental Significance of Siliceous Rocks from Middle Permian Xiala Formation in Chunzhe Area, Xietongmen County, Tibet
摘要
Abstract
Based on field geological survey and main,REE and trace elements analyses,the genesis and geological and tectonic environment of the siliceous rocks from middle Permian Xiala Formation (P2x) in Chunzhe area,Tibet have been discussed in this paper.The results show that SiO2 and MgO contents of the siliceous rocks from Chunzhe area have negative correlation.In the double variable diagrams of SiO2/Al2O3-MnO/TiO2 and Fe2O3/FeO-SiO2/Al2O3,they are plotted into the area of hydrothermal sedimentary rocks.The contents of Ag,As and Sb are much higher than the average value of these elements in the crust,and the Ni/Co and Ti/V ratios vary from 0.11 to 2.05 and from 35.90 to 48.37,respectively.The Al/ (Al+Fe) ratio and MnO/TiO2 are relatively low,the values of (La/Yb)N,(La/Ce)N and (Ce)N range from 1.35 to 1.97,from 1.08 to 1.15 and from 0.89 to 0.95,respectively.Combined with mass shallow marine carbonate rocks developed within Xiala formation,the conclusions can be drawn that the siliceous rocks in Chunzhe area was formed in a shallow marine tectonic environment of continental margin,which belong to the hydrothermal sedimentary siliceous rocks related to volcanic activity.The discovery of hydrothermal sedimentary siliceous rocks shows that the volcanic hydrothermal exhalative event should happen at the west Gangdese metallogenic belt in middle Permian.Large lead-zinc polymetallic exhalative deposit had been discovered at Paleozoic Laigu formation in east Gangdise metallogenic belt,which indicate a good prospect to find similar mineral resources in the west Gangdise metallogenic belt.关键词
热水沉积/硅质岩/元素地球化学/构造环境/中二叠统下拉组/西藏春哲Key words
hydrothermal sedimentary/siliceous rocks/element geochemistry/tectonic environment/Middle Permian Xiala Formation/Chunzhe area in Tibet分类
天文与地球科学引用本文复制引用
刘伟,杨长青,丰耀东,李开文,柴建玉,茹朋,白何领,王柳林..西藏谢通门县春哲地区中二叠统下拉组硅质岩地球化学特征及构造环境意义[J].西北地质,2018,51(1):65-76,12.基金项目
中国地质调查局矿产远景调查项目“西藏春哲地区矿产远景调查”(1212011086055) （1212011086055）
