本文關(guān)鍵詞： 礦床地質(zhì) 流體包裹體 穩(wěn)定同位素 礦床成因 磨溝金礦　出處：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：磨溝金礦位于華北地塊南緣熊耳山-外方山地區(qū),華北陸塊南緣是我國第二大金礦產(chǎn)地。本文在收集熊耳山地區(qū)前人研究資料的基礎(chǔ)上,對(duì)礦床的地質(zhì)特征、C-H-O-S穩(wěn)定同位素地球化學(xué)特征以及流體包裹體等特征等進(jìn)行了詳細(xì)的研究,探討了磨溝金礦成礦物質(zhì)來源和成礦流體的特征、演化和來源,解析礦床成因和成礦機(jī)制,論文取得的主要認(rèn)識(shí)概括如下:(1)磨溝金礦床的礦體主要賦存于熊耳群火山巖中,呈脈狀受北東向斷裂控制。圍巖蝕變以硅化為主,其次為鉀化、碳酸鹽化和高嶺土化等。礦石結(jié)構(gòu)主要有自形-半自形晶粒狀結(jié)構(gòu)、乳滴狀結(jié)構(gòu)和侵蝕結(jié)構(gòu)等。礦石構(gòu)造主要有浸染狀構(gòu)造和脈狀構(gòu)造等。熱液活動(dòng)劃分為石英?黃鐵礦階段、石英?多金屬硫化物階段和石英?碳酸鹽階段。(2)磨溝金礦床流體包裹體類型以氣液兩相包裹體和含CO2三相包裹體為主。形態(tài)主要有方形、橢圓形和月牙形等。包裹體成分有CO2、CH4、H2O和H2S等。包裹體完全均一溫度峰值從220~280℃到160~220℃最后再到160~180℃逐步演化;鹽度主體范圍從8~16wt.%Na Cl.eqv到6~12wt.%Na Cl.eqv再到0~8wt.%Na Cl.eqv;密度從0.82~1.09g/cm~3變化到0.89~0.98 g/cm~3再演化到0.89~0.97 g/cm~3。成礦壓力峰值在20~30 MPa范圍內(nèi),成礦主階段壓力均值為27.48MPa;成礦深度峰值在2~3 km范圍內(nèi),成礦主階段深度均值為2.76km。成礦流體總體上顯示中溫、中低鹽度和低密度的特征。(3)磨溝金礦C-H-O同位素分析表明成礦流體來源于變質(zhì)水和大氣水的混合。S同位素分析顯示成礦物質(zhì)來源于重熔的太華群。通過與典型金礦床的地質(zhì)和地球化學(xué)特征對(duì)比,磨溝金礦屬于造山型金礦。沸騰作用和水巖反應(yīng)是金礦沉淀的主要機(jī)理。成礦流體攜帶來自重熔太華群的成礦物質(zhì)通過馬超營(yíng)斷裂等導(dǎo)礦構(gòu)造運(yùn)移至其北東向次級(jí)斷裂,通過沸騰作用和與熊耳群地層的水巖反應(yīng),流體與大氣降水混合,萃取了部分熊耳群的成礦物質(zhì),并在合適的位置沉淀成礦。
[Abstract]:Mogou gold deposit is located in Xiongershan-Waifangshan area on the southern margin of North China block, and the southern margin of North China block is the second largest gold deposit in China. The geological characteristics of the deposit and the characteristics of stable isotopic geochemistry of C-H-O-S and fluid inclusions are studied in detail, and the characteristics, evolution and origin of ore-forming materials and ore-forming fluids in Mogou gold deposit are discussed. By analyzing the genesis and metallogenic mechanism of the deposit, the main knowledge obtained in this paper is summarized as follows: (1) the orebody of the Mogou gold deposit mainly occurs in the volcanic rocks of Xiong er group, and is controlled by NE faults. The main alteration of surrounding rock is silicification, followed by potassium. Carbonation and kaolinization. The ore structure mainly consists of self-shape and semi-automorphic grain structure, emulsion droplet structure and erosion structure, etc. The ore structure is mainly dyed structure and vein structure, etc. The hydrothermal activity is divided into quartz? Pyrite stage, quartz? Polymetallic sulphide stage and quartz? In carbonate stage, the fluid inclusions in Mogou gold deposit are mainly gas-liquid two-phase inclusions and CO2 three-phase inclusions. The inclusions are composed of CO _ 2H _ 4H _ 2O and H _ 2S. The peak values of the complete homogenization temperature range from 220 ~ 280 鈩，

本文編號(hào)：1552270