铜陵刺山矽卡岩金矿地质学和矿物学

发布时间：2018-02-11 11:01

本文关键词： 地质学岩相学和矿物学矽卡岩金矿铜陵刺山　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：刺山金矿位于安徽省铜陵市狮子山矿田内,矿体主要产于辉石闪长岩岩体与分水岭组灰岩地层接触带部位。本文通过对刺山金矿的矿区地质、矿床地质、矽卡岩岩相学和矿物学的研究,尤其是对主要矽卡岩矿物进行详细的岩相学和矿物学研究,探讨了刺山金矿矽卡岩成因和矿床成因。通过对比铜陵地区矽卡岩金矿和矽卡岩铜矿的矽卡岩矿物学特征,寻找两者的异同点,对于探讨这两类矿床的矽卡岩成因、矿床成因机制以及开展成矿预测具有重要的意义。通过野外调研和室内研究发现,刺山金矿矽卡岩属于典型接触交代成因矽卡岩中的钙矽卡岩。矽卡岩与围岩和岩体呈渐变式分带特征,具有典型的接触交代式的分带现象。矽卡岩矿物主要由石榴石、辉石、绿帘石、绿泥石、阳起石等组成。电子探针数据分析结果表明,矿区石榴石属于钙铝榴石-钙铁榴石固溶体系列,而辉石属于透辉石-钙铁辉石固溶体系列,并以透辉石为主。石榴石和辉石的矿物组分分别为And0~97.42Gro11.40~84.21Other0~12.46和Di51.53~88.56Hd8.40~45.00Other0.02~0.07,石榴石和辉石较大的成分变化特征反映出刺山金矿矽卡岩不是在一个完全封闭的平衡条件下形成的。根据矿体产出特征和矿物共生组合特征,可将刺山金矿的成矿过程划分成气成-高温热液期和热液期。气成-高温热液期进一步分为早矽卡岩阶段、晚矽卡岩阶段和磁铁矿阶段,热液期划分成石英-硫化物阶段和碳酸盐阶段。石英-硫化物阶段中,在低氧逸度、低硫浓度、低温且碱性的环境下,金的硫络合物解体,金元素在该阶段大量沉淀,形成了刺山矽卡岩型金矿,因此石英硫化物阶段是主成矿阶段。研究矽卡岩金矿和矽卡岩铜矿的矽卡岩矿物组合发现:两者的主要矽卡岩矿物都是以石榴石、辉石为主,其他次要矿物有绿帘石、阳起石、绿泥石、石英、方解石等。石榴石都为钙铁-钙铝榴石系列,不同的是钙铝榴石和钙铁榴石含量不同;辉石都是透辉石-钙铁辉石系列,都以透辉石为主;次要矿物种类大致相同,但是各个矿物含量不尽相同。矽卡岩金矿和矽卡岩铜矿的石榴石主量元素特征具有相似特征,也有不同之处。矽卡岩金矿和矽卡岩铜矿的辉石Mn/Fe比值都比较小,大多数小于0.2。矽卡岩铜矿辉石的Mg/Fe比值变化范围比较大,而矽卡岩金矿辉石的Mg/Fe比值比较稳定,变化范围小。
[Abstract]:The Qishan gold deposit is located in the Shizishan Orefield of Tongling City, Anhui Province, and the orebody mainly occurs in the contact zone between the pyroxene diorite and the limestone strata of the Fenshuiling formation. The study of petrography and mineralogy of skarn, especially the detailed petrography and mineralogy of the major skarn minerals, The origin of skarn and skarn ore deposits in the Cishan gold deposit are discussed. By comparing the skarn and skarn mineralogical characteristics of the skarn gold deposit and skarn copper deposit in Tongling area, the similarities and differences between the two types of skarn ore deposits are sought, and the skarn genesis of the two types of deposits is discussed. The genetic mechanism and metallogenic prediction of the deposit are of great significance. Skarn belongs to calcium skarn in skarn of typical contact metasomatic origin. Skarn is characterized by gradual zonation with surrounding rock and rock mass, which is characterized by typical contact metasomatic zonation. Skarn minerals are mainly composed of garnet and pyroxene. The results of electron probe data analysis show that the garnet belongs to the series of calcium aluminite-calcium iron garnet solid solution, while the pyroxene belongs to diopside-calcium iron pyroxene solid solution series. The mineral components of garnet and pyroxene are And0~97.42Gro11.40~84.21Other0~12.46 and Di51.53 88.56Hd8.40U 45.00Other0.020.07respectively. The larger composition variation characteristics of garnet and pyroxene indicate that skarn was not formed under a completely closed equilibrium condition. According to the characteristics of orebody production and mineral symbiotic assemblage, The metallogenic process of Cishan gold deposit can be divided into gas-high-temperature hydrothermal period and hydrothermal period. The gas-high-temperature hydrothermal period can be further divided into early skarn stage, late skarn stage and magnetite stage. The hydrothermal period is divided into quartz-sulphide stage and carbonate stage. In the quartz-sulfide stage, in the low oxygen fugacity, low sulfur concentration, low temperature and alkaline environment, the sulfur complex of gold disintegrates, and the gold element is precipitated in large quantities. The skarn mineral assemblage of skarn gold deposit and skarn copper deposit is studied. The main skarn minerals are garnet and pyroxene. Other minor minerals include verdant, actinolite, chlorite, quartz, calcite, etc. Garnet is a series of calcium ferrite-calcium aluminite garnet, with different contents of calcium aluminite and calcium iron garnet; pyroxene is diopside-calcium iron pyroxene series, The major elements of garnet in skarn gold deposit and skarn copper mine are similar. There are also differences. The Mn/Fe ratio of pyroxene in skarn gold deposit and skarn copper deposit is relatively small, most of them are less than 0.2. The range of variation of Mg/Fe ratio of pyroxene in skarn copper deposit is larger than that in skarn gold deposit, but the Mg/Fe ratio of skarn gold deposit is stable and small.
【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】：2015
【分类号】：P618.51

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