豫西南栾川地区铅锌矿床碳、氧同位素地球化学

Carbon and Oxygen Isotope Compositions of Gangue Carbonates in Pb-Zn Ore Deposits in Luanchuan District,Southwest Henan Province

豫西南地区铅锌矿产勘查工作近年来进展迅速,尤其在栾川地区先后发现十余处铅锌银多金属矿脉群、上百条含矿断裂带,铅、锌、银资源前景广阔。对该区铅锌矿的科学研究丰富了华北陆块南缘区域成矿学认识,并促进了进一步找矿勘查工作。栾川地区铅锌矿产在燕山期斑岩体周围矽卡岩中和外围的断裂带(脉状)中。脉状铅锌矿脉石矿物碳酸盐C、O同位素的组成(赤土店矿床1δ3C为-3.66‰^-2.82‰,1δ8O为10.31‰~15.86‰;百炉沟矿床1δ3C为-3.00‰~1.80‰,1δ8O为9.40‰~17.70‰;冷水北沟矿床1δ3C为-4.90‰^-0.40‰,1δ8O为6.00‰~12.50‰)介于典型海相石灰岩(1δ3C为0±2‰,1δ8O为28‰~30‰)和岩浆岩(1δ3C为-3‰^-30‰,1δ8O为6‰~12‰;地幔1δ3C为-7‰^-5‰)之间,指示成矿流体、成矿物质的岩浆和地层双重作用、两种来源特点。综合分析认为,栾川地区铅锌矿有矽卡岩型和岩浆热液充填-交代型两种。

It has been made a big progress in Pb-Zn Prospecting in southwestern Henan Province recently.Especially,more than ten vein groups of Pb-Zn-Ag mineralization（more than 100 Pb-Zn-Ag veins） have been found in Luanchuan district,which shows a broad prospection of Pb-Zn-Ag resources.The scientific research on these Pb-Zn-Ag ore veins enriches knowledge on regional metallogeny of southern margin of North China Craton and promotes the pace of Pb-Zn prospecting.Pb-Zn ores in Luanchuan district occur in skarn around Yanshannian porphyries or in fractures（vein type） peripheral to Yanshannian porphyries.Gangue carbonate of vein type Pb-Zn ore has carbon and oxygen isotope compositions（Chitudian Pb-Zn deposit： δ13C ranges from-3.66‰ to-2.82‰ and δ18O ranges from 10.31‰ to 15.86‰;Bailugou Pb-Zn deposit： δ13C ranges from-3.00‰ to 1.80‰,δ18O ranges from 9.40‰ to 17.70‰;Lengshuibeigou Pb-Zn deposit： δ13C ranges from-4.90‰ to-0.40‰,δ18O ranges from 6.00‰ to 12.50‰） between typical marine limestone（δ13C is 0 ± 2‰,δ18O ranges from 28‰ to 30‰） and magmatic rock（δ13C ranges from-3‰ to-30‰,δ18O ranges from 6‰ to 12‰;mantle： δ13C ranges from-5‰ to-7‰）,which shows the ore forming fluid and metals bear characteristics of dual function and both sources of magma and strata.It can be concluded from synthetic analysis that Pb-Zn ore deposits in Luanchuan district are skarn type or magmatic hydrothermal filling-metasomatic type.