中国地质2012，Vol.39Issue(2)：311-325,15.
秦岭山阳水沟口组黑色岩系微量元素地球化学及其沉积成矿背景的指示意义
Trace element geochemical characteristics of the Shuigoukou Formation black rock series in Shanyang area of the Qinling Mountains and their indication significance for sedimentation-mineralization
摘要
Abstract
According to field investigation, it is found that the black rock series of Shuigoukou Formation in Shanyang area of the Qinling Mountains is made up of micritic limestone,carbonaceous argillite, claystone, carbonaceous siliceous argillite, carbonaceous limestone and silicalite. Phosphatic nodule and barite are commonly seen in these rocks. The abundances of rare earth elements and some trace elements such as V,Ni,Co,U,Th in the black rock series were measured using ICP-MS method. Some conclusions have been reached; 1) The average concentrations of ore-forming elements (such as V,Mo,Ni,Ba,Pb,Zn,U,Ag,Cu,Cd,Tl,Bi and Cr) are several times to dozen times higher than their crustal abundances), showing that they are rich in the rock series, especially in silicolites and argilloid. Higher content of trace elements and rare earth elements is closely related to phosphorus,TOC and barium. 2)Different concentrations of rare earth elements are connected with different types of rock. The black rock series is usually of the LPvEE -enriched type. 3) The samples are characterized by slight or intermediate negative Ce anomalies (δ Ce =0.40~1.00) and distinct positive Eu anomalies, exclusively with high δ Eu (>2.1). 4)The ratios of U/Th display a large variation from 0.31 to 28.7, the ratios of w (V) /w (V +Ni) ( 0.51~1) and w (Ni) /w (Co) (4.8~49) are relatively high,the ratios of w (Ce) / w (La) (0.68~1.89) are normal, and the average rate of?w (Co) /w (Zn) is 0.21. According to a comparison of these related parameters of PvEE and trace elements with the available data in the references and the La/Yb- Ce/ La and La/Yb - PvEE diagrams, it is suggested that the black rock series of Shuigoukou Formation was formed in the environment of a dry, anoxic and profundal to semi-profundal faulted depression sea basin belonging to a passive continental margin, with the action of hydrothermal fluids.关键词
水沟口组/黑色岩系/地球化学/干燥缺氧环境/秦岭Key words
Shuigoukou Formation/black rock series/ geochemistry/dry and anoxic environment/Qinling分类
天文与地球科学引用本文复制引用
王立社,张复新,侯俊富,房波,周燕..秦岭山阳水沟口组黑色岩系微量元素地球化学及其沉积成矿背景的指示意义[J].中国地质,2012,39(2):311-325,15.基金项目
西北有色地勘局地勘院科研项目“陕西南部黑色岩系金属矿床成矿规律及找矿预测研究”(地勘[2006])和青年基金科学项目“英格里克和清水泉镁铁质-超镁铁质岩成因研究”(41103021)资助. （地勘[2006]）
