内蒙古红花沟金矿床的流体包裹体研究  

A FLUID INCLUSION STUDY OF THE HONGHUAGOU GOLD DEPOSIT, INNER MONGOLIA

作　　者：李荫清[1] 艾永德[1] 

机构地区：[1]中国地质科学院矿床地质研究所,北京100037

出　　处：《矿物学报》1991年第4期346-354,共9页Acta Mineralogica Sinica

摘　　要：含金石英脉产于角闪斜长片麻岩的内蒙古红花沟和莲花山金矿床。石英中流体包裹体以气液比为(5～30)%的两相H_2O包裹体为主,很少见到富气H_2O包裹体,有少量CO_2-H_2O包裹体,其初熔温度为-56.6～-56.3℃,CO_2临界温度平均为+16.1℃,CO_2水合物消失温度为+5.6℃。成矿流体主要为含少量CO_2的均一的NaCl-H_2O溶液。盐度平均为(4.75～6.73)wt%NaCl,包裹体δD为(-85.5～-97.7)‰,δ^(18)O_(H_2O)为(-2.0～+2.1)‰,δ^(13)C_(co_2)为(-8.3～-2.2)‰,表明成矿流体来源于岩浆水和天水。引起金氯络合物分解的主要因素是温度的变化,成矿过程中多量天水的渗入,使体系温度下降至180～240℃,并导至溶液由酸性向中性(pH=5～6)转化,在f_(02)约为10^(-35)～10^(-41)Pa,Eh约为0.5时,产生自然金的沉淀,Fluid inclusions in quartz of auriferous quartz veins, which occur in amphibole-plagioclase-gneisses of the Honghuagou and Lianhuashan gold deposits, are mostly two-phase H_2O inclusions with gas liquid ratio of(5～30)%, some of them are CO_2-H_2O inclusions Gas-rich H_2O inclusions are present only in small amounts. Their eutectic temperatures are-56.6～-56.3℃. The average critical temperature of CO_2 is 16.1℃. The disappearance temperature of clathrate is 5.6℃. The composition of the inclusions also indicates that the ore fluid is a homogeneous NaCl-H_2O solution with minor CO_2. The salinites of the inclusions are (4.57～6.73) wt.% NaCl. δD are (-85.5～97.7)%, δ^(18)O_(H_2O)(- 2.0～+ 2.1)‰, and δ^(13)C_(CO_2),(-8.3～-2.2)‰. All this indicates that the ore-fluid is the mixture of magmatic water and meteoric water. The main factor leading to decomposition of metal complexes is the involvement of much meteoric water during mineralization. The involvement of meteoric water caused the temperature of the ore solution dropped to 180～240℃ and the ore solution changed from acid to neutral (pH=5～6). At this time, f_(o_2) is about 10^(-35)～10^(-14)Pa and Eh is about 0.5V. Native gold is thought to have been precipitated in such an environment.

关 键 词：金矿 矿床 流体 包裹体 内蒙古 

分 类 号：P618.510.5[天文地球—矿床学]