安徽大别山硬玉石英岩地球化学特征及其地质意义  

GEOCHEMICAL CHARACTERISTICS OF JADEITE QUARTZITE IN THE DABIE MOUNTAIN, ANHUI PROVINCE AND THEIR GEOLOGICAL IMPLICATIONS

作　　者：吴峥[1] 李双应[1] WU Zheng;LI Shuang-ying(School of Resource and Environmental Engineering,Hefei University of Technology,Hefei,Anhui 230009,China)

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《安徽地质》2018年第2期81-85,126,共6页Geology of Anhui

摘　　要：硬玉石英岩是大别山超高压变质带的重要成员。硬玉石英岩主量元素平均含量为SiO_2 72.73%、Al_2O_311.77%、MgO1.61%、Fe_2O_3 5.00%、Na_2O 5.45%、K_2O 0.22%、TiO_2 0.59%,具有明显的富硅、富铁、富钠的特征;特征微量元素平均含量Th 10.12×10^(-6)、U 1.94×10^(-6)、Hf 10.91×10^(-6)、Sc 7.68×10^(-6)、Zr 437.05×10^(-6)、Nb 15.81×10^(-6)、Y 45.36×10^(-6)、Ba 141.88×10^(-6)、Sr 30.07×10^(-6);Th/U为5.18、Th/Sc为1.56、La/Sc 9.50;∑REE平均含量223.07×10^(-6),(La/Yb)N 7.01,δEu=0.61,Eu负异常明显,轻稀土富集。原岩恢复结果为富钠的杂砂岩,原岩可能形成于古元古代扬子大陆板块的活动大陆边缘,在中生代三叠纪与华北板块碰撞过程中经受了超高压变质作用。Jadeite quartzite i s an important member of the ultrahigh pressure metamorphic belt of the Dabie Mountain.The average contents of main elements in jadeite quartzite are 72.73%for SiO2,11.77%Al2O3,1.61%MgO,5.00%Fe2O3,5.45%Na2O,0.22%K2O and 0.59%TiO2,showing remarkable Si-Fe-Na-rich features.Average contents of characteristic trace elements are 10.12x10^-6 for Th,1.94x10^-6 U,10.91x10^-6 Hf,7.68x10^-6 Sc,437.05x10^-6 Zr,15.81x10^-6Nb,45.36x10^-6Y,141.88x10^-6Ba,30.07x10^-6Sr;5.18 Th/U,1.56 Th/Sc,9.50La/Sc;the average content ofΣREE is 223.07x10^-6,(La/Yb)N 7.01,Eu=0.61,distinct negative anomaly of Eu.Protolith reconstruction result is sodium-rich graywacke,which possibly formed in the Paleoproterozoic active continental margin of the Yangtze continental plate,and suffered ultra-high pressure metamorphism during the process of collision with North China Plate in Mesozoic Triassic.

关 键 词：地球化学 原岩恢复 构造背景 硬玉石英岩 大别山超高压变质带 

分 类 号：P588[天文地球—岩石学] P584[天文地球—地质学]