阳山金矿带成矿作用：载金矿物结构与组成约束

发布时间：2018-02-15 14:47

本文关键词： 阳山金矿带矿物结构化学成分成矿作用　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：阳山金矿带位于西秦岭造山带南亚带,是西秦岭地区已探明规模最大的独立金矿,其成矿作用独具特色,是通过研究矿石矿物共生序列与地球化学组成来厘定金的成矿作用的理想选区。论文针对阳山金矿带主要载金矿物黄铁矿和毒砂的结构以及化学组成,运用岩相学和地球化学方法,主要取得如下成果与认识:1、矿带的赋矿岩石是泥盆纪三河口群地层和花岗质岩脉。其矿化样式主要为微细浸染状矿化(黄铁矿-毒砂矿化蚀变花岗斑岩(或石英斑岩、花岗岩)型矿石、蚀变千枚岩型矿石、蚀变结晶灰岩型矿石和蚀变变质石英砂岩型矿石),亦发育少量脉状-细脉状矿化(黄铁矿-毒砂-石英脉型矿石和辉锑矿-石英脉型矿石)。2、阳山金矿带的金主要以不可见金形式赋存于硫化物内,少量以自然金形式存在于成矿晚阶段辉锑矿-石英脉中。黄铁矿和毒砂是主要的载金矿物,含金黄铁矿单矿物内见较多位错,但未见独立金矿物,结合黄铁矿的微量元素测试结果:在Au-As图解中,所有成矿阶段黄铁矿的投点均位于金溶解度曲线之下,推断在含金黄铁矿中,金主要以晶格金(Au+)的形式存在。3、沉积-变质期黄铁矿Py0富集Cu、Pb、Sb、Co、Ni、Bi和Mo元素;成矿早阶段Py1中最富集Ag和Te;成矿主阶段Py2中最富集Au(388.33ppm)和As;成矿晚阶段Py3中最富集Mn和Zn。成矿主阶段毒砂富集Cu、Pb、Sb,Bi、Ag和Au(632.09ppm)。成矿晚阶段辉锑矿含有少量Au(0.12ppm),Ag,Cu,Zn和Cr,较为富集Pb。成矿主阶段的黄铁矿和毒砂As和Au元素含量最高,根据主量及微量元素特征判断,其富集可能存在As替代S、Au+替代Fe2+的双交代机制。4、赋矿地层千枚岩中的沉积-变质期黄铁矿含有一定量金(0.32ppm),它可能在后来的变质作用过程中为阳山金矿带提供了金等成矿元素。
[Abstract]:The Yangshan gold belt, located in the South Asia belt of the West Qinling orogenic belt, is the largest independent gold deposit in the West Qinling area, and its mineralization is unique. This paper aims at the structure and chemical composition of pyrite and arsenopyrite, which mainly carry gold ore in Yangshan gold belt, by studying ore mineral symbiotic sequence and geochemical composition. Using petrographic and geochemical methods, The ore-bearing rocks of the ore belt are the strata of the Devonian Sanhekou Group and the granitic veins. The mineralization patterns are mainly micro-disseminated mineralization (pyrite-arsenopyrite mineralization altered granitic porphyry or quartz porphyry). Granite) type ore, altered phyllite type ore, Altered crystalline limestone type ore and altered metamorphic quartz sandstone type ore also developed a small amount of vein-vein-vein mineralization (pyrite arsenopyrite quartz vein type ore and stibnite quartz vein type ore), the gold of Yangshan gold belt is mainly gold. In the form of invisible gold in the form of sulphides, Pyrite and arsenopyrite are the main gold bearing minerals, and there are many dislocations in the single mineral of gold-bearing pyrite, but no independent gold deposits. Combined with the trace element test results of pyrite: in the Au-As diagram, the input points of pyrite in all metallogenic stages are below the gold solubility curve, and it is inferred that the pyrite is in gold-bearing pyrite. Gold mainly exists in the form of lattice gold au), and Py0 enriched Cu Pb-Pb-SbSb-Co-NiOBi and Mo elements in the deposition-metamorphic stage of pyrite. In the early stage of mineralization, Py1 is the most enriched in Ag and Te; in the main stage of mineralization, in Py2 (388.33 ppm) and in As. in the late stage of mineralization, in Py3, it is the most enriched in mn and Zn.The main stage of mineralization is mainly enriched with arsenopyrite, and the main stage of mineralization is enriched with CuPb (SB) and AuLi 632.09 ppm0.The late stage of metallogenic antimony contains a small amount of Auo 0.12 ppm of Ag-Ag-Cu Zn and Cr, which is relatively rich in the later stage of mineralization. The contents of as and au in pyrite and arsenopyrite are the highest in the main metallogenic stage. According to the principal quantity and the characteristics of trace elements, There may be a double metasomatism mechanism of replacement of Fe2 by as in enrichment. The sedimentary metamorphic pyrite in the phyllite of ore-bearing strata may contain a certain amount of au 0.32 ppm-1, which may provide gold and other metallogenic elements for the Yangshan gold belt during the subsequent metamorphism.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.51

【相似文献】