康定金矿田与田湾金矿田地质特征对比研究
发布时间：2019-04-25 21:57
【摘要】：康定金矿田和田湾金矿田是大渡河金成矿带中最重要的两个矿田,但由于康定金矿田地质环境特殊,研究程度一直较低,近年以来略有提高;田湾金矿田研究时间早、研究程度高。为了弄清康定金矿田的矿床地质特征和成因,以及与田湾矿田的联系,本文以康定金矿田典型矿床为重点研究对象,在野外地质调查和室内测试分析以及综合研究的基础上,从矿床地质特征、矿床地球化学和成矿时代等方面进行了研究,对康定金矿田与田湾金矿田基本特征进行了对比。在此基础上,讨论了大渡河金成矿带的成因。矿床地质特征研究表明,康定矿田的典型矿床分别产自前震旦系康定杂岩基底和新元古代-古生代沉积盖层中;田湾矿田则主要产于新元古代-古生代沉积盖层的震旦系白云岩中。矿石矿物成分较简单,金属矿物主要为硫化物,非金属矿物主要为石英。矿物共生组合上:具有较强的相似性,以自然金-多金属硫化物和黄铁矿-石英型矿石为主,此外还含有一定量的碲化物。控矿构造上,康定矿田和田湾矿田均表现出极强的相似性。矿床的分布严格受控于韧脆性剪切带及次级剪切带,整体展布与断裂构造的走向基本一致,主要以北北东、北北西为主。围岩蚀变微弱,以黄铁矿化和硅化为主,均属于中低温热液蚀变。研究表明,康定金矿田的控矿构造在空间上表现为:基底以脆-韧性或韧-脆性剪切带为主,盖层以脆性断裂带为主;时间上表现为早期脆-韧性逆冲,后期韧-脆性伸展。通过年代学研究发现,康定金矿田与田湾矿田成矿时代较为一致,集中在(15~20Ma),主要成矿时代为新生代喜山期。少部分基底中矿床的成矿时代还分布在4~8 Ma、36~40 Ma、48~50 Ma,表现出多期多阶段的特征。康定金矿田与田湾金矿田的元素地球化学、同位素地球化学和流体包裹体的对比研究表明,以上两地稀土元素总量变化较小,REE配分模式呈右倾曲线,属于轻稀土元素相对于重稀土元素富集型,呈负Ce异常。硫同位素特征显示,康定金矿田硫同位素组成较为稳定,均一化程度较高;田湾金矿硫同位素组成略微复杂,但两矿田均具幔源硫特征。据石英包裹体特征显示,其均一温度集中在130~280℃,属中低温热液流体。氢氧同位素显示,成矿流体中水的来源较为复杂,总体呈岩浆水、变质水和大气水的混合特征。通过对康定金矿田不同赋矿层位的矿床特征总结,以及与田湾金矿田的特征对比研究,认为两矿田成因相同,属于同一成矿系列。同时根据康定金矿田和田湾金矿的矿床地质特征和元素组合分析,认为大渡河金矿带属于中浅成造山型金矿。
[Abstract]:The Kangding gold field and the Tianwan gold field are the most important two ore fields in the Daduhe gold metallogenic belt, but due to the special geological environment of the Kangding gold field, the research degree has been relatively low and has been slightly improved in recent years. The research time of Tianwan gold field is earlier and the degree of research is high. In order to understand the geological characteristics and genesis of the Kangding gold deposit and its relation with the Tianwan gold field, this paper focuses on the typical ore deposits in the Kangding gold field, on the basis of field geological investigation, laboratory test and analysis, and comprehensive research. In this paper, the geological characteristics, geochemistry and metallogenic age of the deposit are studied, and the basic characteristics of the Kangding gold field and the Tianwan gold field are compared. On this basis, the genesis of the Daduhe gold metallogenic belt is discussed. The study on the geological characteristics of the deposit shows that the typical deposits in the Kangding ore field are from the pre-Sinian Kangding complex basement and the Neoproterozoic-Paleozoic sedimentary cap. The Tianwan ore field mainly occurs in the Sinian dolomite of the Neoproterozoic-Paleozoic sedimentary caprock. Ore mineral composition is relatively simple, metal minerals are mainly sulfides, non-metallic minerals are mainly quartz. Mineral symbiotic assemblage: there is strong similarity, mainly natural gold-polymetallic sulphides and pyrite-quartz ores, in addition to contain a certain amount of telluride. In ore-controlling structure, both Kangding ore field and Tianwan ore field show strong similarity. The distribution of the deposit is strictly controlled by ductile-brittle shear zone and secondary shear zone. The distribution of the deposit is basically consistent with the strike of the fault structure, mainly north-east and northwest-west. Peri-rock alteration is weak, mainly pyrite mineralization and silicification, all belong to medium-low temperature hydrothermal alteration. The results show that the ore-controlling structure of Kangding gold field is characterized by brittle-ductile or ductile-brittle shear zone and brittle fracture zone in the cap layer, and brittle-ductile thrust in the early stage and ductile-brittle extension in the later stage of the ore-controlling structure in the Kangding gold field. By means of chronological study, it is found that the ore-forming ages of Kangding gold field and Tianwan ore field are more consistent, concentrated in (15~20Ma), and the main ore-forming age is the Cenozoic Himalayan age. The ore-forming ages of the deposits in a small part of the basement are also characterized by multi-stage and multi-stage distribution at 4 ~ 8 Ma,36~40 Ma,48~50 Ma,. The comparison of element geochemistry, isotope geochemistry and fluid inclusions between the Kangding gold field and the Tianwan gold field shows that the total amount of rare earth elements in the above two areas varies little, and the REE partition model shows a right dip curve. It belongs to the enrichment type of light rare earth elements (LREE) relative to heavy rare earth elements (HREE), showing negative Ce anomaly. The sulfur isotopic characteristics show that the sulfur isotopic composition of the Kangding gold field is relatively stable and the degree of homogenization is higher, while the sulfur isotopic composition of the Tianwan gold deposit is slightly complex, but both of the two ore fields have mantle-derived sulfur characteristics. According to the characteristics of quartz inclusions, the homogenization temperature is concentrated at 130 鈩，
本文编号：2465496
[Abstract]:The Kangding gold field and the Tianwan gold field are the most important two ore fields in the Daduhe gold metallogenic belt, but due to the special geological environment of the Kangding gold field, the research degree has been relatively low and has been slightly improved in recent years. The research time of Tianwan gold field is earlier and the degree of research is high. In order to understand the geological characteristics and genesis of the Kangding gold deposit and its relation with the Tianwan gold field, this paper focuses on the typical ore deposits in the Kangding gold field, on the basis of field geological investigation, laboratory test and analysis, and comprehensive research. In this paper, the geological characteristics, geochemistry and metallogenic age of the deposit are studied, and the basic characteristics of the Kangding gold field and the Tianwan gold field are compared. On this basis, the genesis of the Daduhe gold metallogenic belt is discussed. The study on the geological characteristics of the deposit shows that the typical deposits in the Kangding ore field are from the pre-Sinian Kangding complex basement and the Neoproterozoic-Paleozoic sedimentary cap. The Tianwan ore field mainly occurs in the Sinian dolomite of the Neoproterozoic-Paleozoic sedimentary caprock. Ore mineral composition is relatively simple, metal minerals are mainly sulfides, non-metallic minerals are mainly quartz. Mineral symbiotic assemblage: there is strong similarity, mainly natural gold-polymetallic sulphides and pyrite-quartz ores, in addition to contain a certain amount of telluride. In ore-controlling structure, both Kangding ore field and Tianwan ore field show strong similarity. The distribution of the deposit is strictly controlled by ductile-brittle shear zone and secondary shear zone. The distribution of the deposit is basically consistent with the strike of the fault structure, mainly north-east and northwest-west. Peri-rock alteration is weak, mainly pyrite mineralization and silicification, all belong to medium-low temperature hydrothermal alteration. The results show that the ore-controlling structure of Kangding gold field is characterized by brittle-ductile or ductile-brittle shear zone and brittle fracture zone in the cap layer, and brittle-ductile thrust in the early stage and ductile-brittle extension in the later stage of the ore-controlling structure in the Kangding gold field. By means of chronological study, it is found that the ore-forming ages of Kangding gold field and Tianwan ore field are more consistent, concentrated in (15~20Ma), and the main ore-forming age is the Cenozoic Himalayan age. The ore-forming ages of the deposits in a small part of the basement are also characterized by multi-stage and multi-stage distribution at 4 ~ 8 Ma,36~40 Ma,48~50 Ma,. The comparison of element geochemistry, isotope geochemistry and fluid inclusions between the Kangding gold field and the Tianwan gold field shows that the total amount of rare earth elements in the above two areas varies little, and the REE partition model shows a right dip curve. It belongs to the enrichment type of light rare earth elements (LREE) relative to heavy rare earth elements (HREE), showing negative Ce anomaly. The sulfur isotopic characteristics show that the sulfur isotopic composition of the Kangding gold field is relatively stable and the degree of homogenization is higher, while the sulfur isotopic composition of the Tianwan gold deposit is slightly complex, but both of the two ore fields have mantle-derived sulfur characteristics. According to the characteristics of quartz inclusions, the homogenization temperature is concentrated at 130 鈩，
本文编号：2465496
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