摘要
辽宁白云金矿是辽东-吉南裂谷带内典型的大型金矿床,其成矿作用复杂,为了深入揭示其成矿流体、成矿物质来源及成矿模式特征,针对白云金矿石进行流体包裹体、H,O,S及与成矿有关的岩体的研究,结果显示:5块金矿石流体包裹体的均一温度范围为152℃~370℃,主要分布在240℃~310℃,激光拉曼成分主要为CO_2和CH_4,有少量H_2O,极少数有N_2;5块金矿石δ^(34)S值为-8.5‰^+1.6‰(平均为-4.85‰),赋矿围岩(黑云片岩、变粒岩)中δ^(34)S值为+10.0‰^+17.0‰(平均为+14.57‰),地层大理岩的δ^(34)S值为-0.5‰^+13.2‰(平均为+7.17‰);5块金矿石石英中δ^(18)O为8.0‰~15.5‰,δD为-96.3‰^-73.6‰;与成矿有关的新岭岩体SHRIMP U-Pb年龄为217.6Ma±2.2Ma。流体包裹体特征表明:成矿流体为中温低盐度低密度的水盐流体,属于含N_2的H_2O-CO_2-CH_4-NaCl体系。流体中CO_2及CH_4形成与大理岩有关,极少数的N_2含量可能与大气水有关。氢氧同位素结果显示,成矿热液主要来源于深部岩浆水,后期混有部分大气降水。硫同位素特征表明,成矿物质可能主要来自岩浆热液。综上,白云金矿床的主成矿期为印支期,白云金矿床属于岩浆热液型金矿。
The fluid inclusions, H,O,S isotopes and mineralization characteristics in the typical large scale Baiyun gold deposit of Liaodong-Jinan rift is studied in order to reveal its complex mineralization, ore-forming fluids, formation depth and mineralization provenance. Homogenization temperatures of fluid inclusions of 5 pieces of gold ore range from 152 ℃ to 370 ℃ ,mainly in 240 ℃ -310 ℃. Laser Raman analysis shows that the ore is composed mainly of CO2 and CH4 ,with a small amount of H2O,a very small number of N2.δ^34S value of the ore is in the range of -8.5‰ ～＋1.6‰ （average -4.85%0）,host rocks （biotite schist,leptite） is in the range of ＋10. 0～＋ 17.0%0 （average of＋ 14.57%0）, and marble formations is --0.5‰～＋13.2‰（average oft 7. 17‰）. The 8～80 value of gold-bearing quartz is 8.0‰～15.5‰,and the 8D value is -96.3‰～ 73.6‰. SHRIMP U-Pb dating for Xinling rock which is related to gold mineralization yields an age of 217.6 Ma±2.2 Ma. Characteristics of fluid inclusions show that the ore-forming fluid be- long to mid temperature,low density water salinity fluid, and contain H2O-CO2-CH4-NaCl system of N2. The formation of CO2 and CH4 in the fluid is related to marble and the formation of N2 is related to meteoric water. It shows that hydrogen and oxygen isotopes,hydrothermal mineralization mainly come from deep magmatic water mixed with late stage formed meteoric water. Sulfur isotope characteristics suggest that ore-forming material mainly originates from magmatic hydrothermal solution. In summary,the main mineralization period of Baiyun gold deposit is Indosinian and the Baiyun gold deposit is a magmatic type gold deposit.
出处
《矿物岩石》
CAS
CSCD
北大核心
2017年第1期30-39,共10页
Mineralogy and Petrology
基金
国家重点研发计划(2016YFC0600108)
中国地质调查局地质资源大调查项目(DD20160049,12120113058800)
