【摘要】：藏南金銻多金屬成礦帶是近十幾年來國內(nèi)外廣大學(xué)者研究與關(guān)注的熱點地區(qū)。本論文以該成礦帶代表性礦床查拉普金礦、馬扎拉金銻礦和邦布金礦為研究對象,在野外地質(zhì)調(diào)查的基礎(chǔ)上,通過對載金礦物手標(biāo)本和電子顯微鏡下的詳細觀察,結(jié)合電子探針分析(EMPA),對三個礦床的載金礦物類型和金的賦存狀態(tài)進行了研究,并進一步對成礦作用演化和礦床類型進行了探討。查拉普金礦床的金主要以不可見金的形式賦存于黃鐵礦和毒砂中。黃鐵礦可以分為沉積成巖期黃鐵礦Py1,熱液期早階段黃鐵礦Py2和熱液期主階段黃鐵礦Py3。Py1多呈草莓狀、膠狀結(jié)構(gòu),其中w(Au)最高,顯示了金在沉積成巖期的大量富集。Py2與Py1元素組成相似,顯示了一定的繼承演化關(guān)系。Py3是含砷黃鐵礦,與毒砂共生,是最重要的載金礦物。Au在Py1和大部分Py2中主要以納米級自然金(Au0)的形式存在。而在Py3中,Au主要以固溶體(Au+)的形式存在。其上述特點符合大多數(shù)卡林型金礦的特征。馬扎拉金銻礦床的金主要以可見的自然金和不可見金兩種形式存在,自然金主要以裂隙金、包裹金和粒間金三種形式賦存于輝銻礦和石英中。不可見金主要賦存于黃鐵礦中。黃鐵礦可以分為沉積成巖期黃鐵礦Py1,熱液期含砷黃鐵礦Py2和Py3。Py1呈草莓狀結(jié)構(gòu),w(Au)較高,顯示了金在沉積成巖期的初步富集。Py2與Py1相比w(As)明顯提高,是不可見金最主要的載金礦物,顯示了熱液早期的流體富含Au、As。部分Py2由于造山作用擠壓而形成破裂狀Py3,這個過程釋放了部分的Au、As進入到變質(zhì)流體。不可見金在Py1中主要以納米級自然金(Au0)的形式存在,在Py2和Py3中主要以固溶體金(Au+)和納米級自然金(Au0)兩種形式存在。其上述特點符合大多數(shù)造山型金礦的特征。邦布金礦床金的主要賦存形式為可見的自然金,其主要以裂隙金、包裹金和粒間金三種形式賦存于石英和黃鐵礦中。不可見金含量相對較低,主要賦存于黃鐵礦和毒砂中。黃鐵礦可以分為自形粗粒黃鐵礦Py1、半自形細粒黃鐵礦Py2和自形細粒黃鐵礦集合體Py3,其中以Py1的碎裂狀核部和Py2含金性最好。不可見金在Py1的碎裂狀核部和Py2中主要以納米級自然金(Au0)的形式存在。其上述特點符合大多數(shù)造山型金礦的特征。
[Abstract]:The gold-antimony polymetallic metallogenic belt in southern Tibet is a hot area studied and paid attention to by scholars at home and abroad in recent ten years. In this paper, the Charap gold deposit, Mazara gold antimony deposit and Bangbu gold deposit in this metallogenic belt are studied. On the basis of the geological investigation in the field, the hand specimens of the gold-carrying mineral and the electron microscope are observed in detail. The types of gold-bearing minerals and the occurrence of gold in the three deposits were studied by means of electron probe analysis (EMPA), and the evolution of mineralization and the types of deposits were further discussed. The gold in the Charap gold deposit is mainly in the form of invisible gold in pyrite and arsenopyrite. Pyrite can be divided into Py1, pyrite in sedimentary diagenetic period, pyrite Py2 in early hydrothermal period and pyrite Py3.Py1 in main hydrothermal stage in strawberry and gelatinous structure, among which w (Au) is the highest. Py2 is similar to Py1. Py3 is arsenic-bearing pyrite, which is symbiotic with arsenopyrite, which is similar to pyrite in sedimentary diagenetic period, and the composition of Py2 is similar to that of Py2 in sedimentary diagenetic period, indicating that Py3 is arsenopyrite. Au is the most important gold-carrying mineral. Au mainly exists in the form of nano-scale natural gold (Au0) in Py1 and most of Py2. In Py3, Au mainly exists in the form of solid solution (Au). The above-mentioned characteristics accord with the characteristics of most Carlin type gold deposits. The gold in Mazara gold-antimony deposit is mainly in the form of visible natural gold and invisible gold, and the natural gold mainly occurs in antimonite and quartz in the form of fissured gold, encapsulated gold and intergranular gold. Invisible gold occurs mainly in pyrite. Pyrite can be divided into sedimentary diagenetic period, pyrite, Py1, hydrothermal period, arsenic-bearing pyrite Py2 and Py3.Py1 have higher strawberry structure, w (Au), indicating the initial enrichment of gold in sedimentary diagenetic period. Py2 is obviously higher than Py1 in w (As). It is the main gold-carrying mineral of invisible gold, which shows that the early hydrothermal fluids are rich in Au,As.. The process of forming ruptured Py3, due to orogenic extrusion of part of Py2 releases part of Au,As into metamorphic fluid. Invisible gold mainly exists in the form of nanometer natural gold (Au0) in Py1, while in Py2 and Py3 it is mainly in the form of solid solution gold (Au) and nanometer natural gold (Au0). The above-mentioned characteristics accord with the characteristics of most orogenic gold deposits. The main occurrence form of gold in Bangbu gold deposit is visible natural gold, which mainly occurs in quartz and pyrite in the form of fissured gold, encapsulated gold and intergranular gold. The content of invisible gold is relatively low and occurs mainly in pyrite and arsenopyrite. Pyrite can be divided into self-shaped coarse-grained pyrite Py1, semi-autogenous fine-grained pyrite Py2 and autogenous fine-grained pyrite aggregate Py3, among which the fragmentation of Py1 and the gold content of Py2 are the best. Invisible gold exists mainly in the form of nano-scale natural gold (Au0) in the fragmentation nucleus of Py1 and in Py2. The above-mentioned characteristics accord with the characteristics of most orogenic gold deposits.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P618.2

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本文編號：2452194