黑龙江伊春大安河金矿成矿流体性质与成矿物质来源

Nature of metallogenetic fluids and material sources in Da'anhe gold deposit,Yichun of Heilongjiang Province

对大安河金矿床的地质特征、流体包裹体和硫、铅同位素研究,进一步厘定该矿床成矿经历了石榴石--透辉石、透闪石--阳起石、磁铁矿、石英--硫化物和石英--方解石等5个阶段,为典型的矽卡岩型矿床。选取典型的三阶段流体包裹体,测得各阶段的成矿温度和盐度分别为:石榴石--透辉石阶段均一温度177℃～600℃,盐度7%～12.2%;石英硫化物阶段均一温度147℃～455℃,盐度1%～5%;石英--方解石阶段均一温度130℃～247℃,盐度0.5%～3%。流体包裹体气相成分主要为CO2、H2O以及少量CH4。矿石中硫化物的δ34SV-CDT为-2.9×10-3～-0.6×10-3,其组成接近零值,表明成矿物质可能来源于地幔。矿石中硫化物206Pb/204Pb=18.099～18.508,207Pb/204Pb=15.532～15.578,208Pb/204Pb=38.071～38.176,反映出成矿物质来源的多元性,为壳幔混合来源。

The research of geological features of ore deposit , fluid inclusion, sulfur and lead isotope has been recognized the ore-forming process consisting of five stages, including garnet-diopside, tremolite-actinolite, magnetite, quartz-sulfide and quartz-calcite stages, which indicates the deposit as a typical skarn in type. The testing results of homogenization temperatures and salinity of typical fluid inclusions from the selected three different mineralization stages show the homogenization temperatures value as 177℃- 600℃ and salinity value as 7% 12. 2% in garnet-diopside stage; homogenization temperatures value of 147~C^455~C and salinity value of 1%5% in quartz-sulfide stage; and homogenization temperatures value of 130℃-247℃ and salinity value of 0. 5%- 3% in quartz-calcite stage. The gas composition of fluid inclusions were of CO2, H2O and a small amount of CH4. The 834SV- CDT of ore sulfide value was -2. 9 × 10^-3- -0. 6 × 10^-3, and the composition was close to zero, which the ore-forming meterals may come from mantle. The ^206pb/^204 Pb was 18.099 - 18. 508,207 pb/2O4 Pb as 15.532- 15.578 and ^208pb/^204pb as 38. 071 - 38. 176 in the ore sulfide, which refelceted the diversity metallogenetic material meterals, derived from a mantle-crust mix.