【摘要】：康定金礦田和田灣金礦田是大渡河金成礦帶中最重要的兩個(gè)礦田,但由于康定金礦田地質(zhì)環(huán)境特殊,研究程度一直較低,近年以來(lái)略有提高;田灣金礦田研究時(shí)間早、研究程度高。為了弄清康定金礦田的礦床地質(zhì)特征和成因,以及與田灣礦田的聯(lián)系,本文以康定金礦田典型礦床為重點(diǎn)研究對(duì)象,在野外地質(zhì)調(diào)查和室內(nèi)測(cè)試分析以及綜合研究的基礎(chǔ)上,從礦床地質(zhì)特征、礦床地球化學(xué)和成礦時(shí)代等方面進(jìn)行了研究,對(duì)康定金礦田與田灣金礦田基本特征進(jìn)行了對(duì)比。在此基礎(chǔ)上,討論了大渡河金成礦帶的成因。礦床地質(zhì)特征研究表明,康定礦田的典型礦床分別產(chǎn)自前震旦系康定雜巖基底和新元古代-古生代沉積蓋層中;田灣礦田則主要產(chǎn)于新元古代-古生代沉積蓋層的震旦系白云巖中。礦石礦物成分較簡(jiǎn)單,金屬礦物主要為硫化物,非金屬礦物主要為石英。礦物共生組合上:具有較強(qiáng)的相似性,以自然金-多金屬硫化物和黃鐵礦-石英型礦石為主,此外還含有一定量的碲化物�？氐V構(gòu)造上,康定礦田和田灣礦田均表現(xiàn)出極強(qiáng)的相似性。礦床的分布嚴(yán)格受控于韌脆性剪切帶及次級(jí)剪切帶,整體展布與斷裂構(gòu)造的走向基本一致,主要以北北東、北北西為主。圍巖蝕變微弱,以黃鐵礦化和硅化為主,均屬于中低溫?zé)嵋何g變。研究表明,康定金礦田的控礦構(gòu)造在空間上表現(xiàn)為:基底以脆-韌性或韌-脆性剪切帶為主,蓋層以脆性斷裂帶為主;時(shí)間上表現(xiàn)為早期脆-韌性逆沖,后期韌-脆性伸展。通過(guò)年代學(xué)研究發(fā)現(xiàn),康定金礦田與田灣礦田成礦時(shí)代較為一致,集中在(15~20Ma),主要成礦時(shí)代為新生代喜山期。少部分基底中礦床的成礦時(shí)代還分布在4~8 Ma、36~40 Ma、48~50 Ma,表現(xiàn)出多期多階段的特征�？刀ń鸬V田與田灣金礦田的元素地球化學(xué)、同位素地球化學(xué)和流體包裹體的對(duì)比研究表明,以上兩地稀土元素總量變化較小,REE配分模式呈右傾曲線,屬于輕稀土元素相對(duì)于重稀土元素富集型,呈負(fù)Ce異常。硫同位素特征顯示,康定金礦田硫同位素組成較為穩(wěn)定,均一化程度較高;田灣金礦硫同位素組成略微復(fù)雜,但兩礦田均具幔源硫特征。據(jù)石英包裹體特征顯示,其均一溫度集中在130~280℃,屬中低溫?zé)嵋毫黧w。氫氧同位素顯示,成礦流體中水的來(lái)源較為復(fù)雜,總體呈巖漿水、變質(zhì)水和大氣水的混合特征。通過(guò)對(duì)康定金礦田不同賦礦層位的礦床特征總結(jié),以及與田灣金礦田的特征對(duì)比研究,認(rèn)為兩礦田成因相同,屬于同一成礦系列。同時(shí)根據(jù)康定金礦田和田灣金礦的礦床地質(zhì)特征和元素組合分析,認(rèn)為大渡河金礦帶屬于中淺成造山型金礦。
[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，

本文編號(hào)：2465496