滇东北驾车穹隆结构及其Pb、Zn、Ag、As、Sb元素异常特征  

Structural and background anomaly characteristics of Pb,Zn,Ag,As,Sb of the Jiache Dome,Northeast Yunnan Province

作　　者：韩阳光 颜丹平[2] 穆丹[2] 邱亮 康宁[1] 陈峰[2] 赵磊[2] 孙琦[2] 李林[2] 邵雨萌[2] 张翼西[2] 

机构地区：[1]辽宁省第六地质大队,辽宁大连116200 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地学前缘》2018年第1期65-79,共15页Earth Science Frontiers

基　　金：国家重点基础研究发展计划"973"项目(2014CB440903);国家自然科学基金项目(41372212;41672216)

摘　　要：滇东北地区位于扬子地块西南部,该区域内发育一系列直接赋存有低温矿床或与低温成矿作用联系密切的构造穹隆体。详细研究这类穹隆体的构造成因及属性,是揭示区域内低温成矿规律的关键。驾车穹隆位于滇东北阿旺镇至驾车乡一带,与滇东北其他穹隆体相比,驾车穹隆出露完整的构造-岩石组合,是该区域构造穹隆体的典型代表。文中以驾车穹隆的构造特征为研究对象,通过详细的地质构造调查与构造解析、重点地层系统样品采集并进行地球化学分析及电子探针分析,结合区域背景资料,确定了穹隆的构造成因及变形序列、主要低温成矿元素背景异常特征及赋存状态。通过对3条横切驾车穹隆体构造剖面的构造解析,厘定了3期构造变形:D1期顺层流变构造,变形时代推测为加里东期;D2期为NEE向纵弯褶皱,变形时代推测为印支期;D3期为NNE向纵弯褶皱,变形时代推测为燕山期。地球化学分析结果表明:穹隆内昆阳群中泥质和粉砂质板岩等低级变质岩中具有3~5倍以上Pb、Zn、Ag、Sb、As元素背景异常;震旦系澄江组粉砂岩、灯影组白云岩与黑色页岩中局部具有3~5倍以上Pb、Ag和As的元素背景异常;下寒武统渔户村组部分黑色页岩中具有5倍以上的Pb、Zn、Ag、Sb、As元素背景异常。电子探针分析结果进一步表明,上述低温成矿元素在原生黄铁矿中富集。综合构造解析结果表明,驾车穹隆主体是一个由NNE向褶皱(D3期)横跨叠加于NEE向褶皱(D2期)之上而形成的构造穹隆体,为印支期与燕山期构造复合的结果。Northeastern Yunnan, located in the southwestern part of the Yangtze Block, developed a series of tectonic domes hosting low temperature or closely related deposits. Research on the structural origin and properties of these tectonic domes is beneficial for revealing the regularity of regional low temperature ore formation. The Jiache Dome in northeast Yunnan situates near Awang and Jiache towns. Compared with other domes in the area, the Jiache Dome developed a complete structurerock assemblage, typical of the regional tectonic domes. Focusing on the structural features of the Jiache Dome, the structural origin and deformation sequences of tectonic domes, characteristics of background anomaly of low temperature metallogenic elements, and occurrence of Pb, Zn, Ag, As, Sb elements were determined in this work, through detailed geological investigation, structural analysis, key stratum sample collection, geochemical and EMPA analyses, in combination with regional background data. By completing three crosscutting structural profiles of the Jiache Dome, it is discovered that the dome has experienced at least three stages of structural deformation （D1, D2, D3）： D1 period developed consequent flow layer deformation, possibly of the Caledonian age; D2 period formed the NEE trending buckling fold with a supposed deformation age of the Indosinian; D3 period resulted in the NNE trending buckling fold, whose deformation age is postulated to be the Yanshanian. Results of geochemical analyses show that lowgrade metamorphic rocks in the Kunyang Group （for example muddy and silty slate） have background anomaly values 3 to 5 times higher than background levels for Pb, Zn, Ag, Sb, As and siltstone in the Chengjiang Formation of Sinian. Similarly, dolomite and black shale in the Dengying Formation exhibit background anomaly levels 3 to 5 times higher than background values for Pb, Ag, and As. And part of black shales in the Yuhucun Formation of the lower Cambrian show background anomaly values 5 times higher than ba

关 键 词：驾车穹隆 构造变形序列 构造样式 叠加褶皱 元素富集 

分 类 号：P542[天文地球—构造地质学] P595[天文地球—地质学]