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内蒙古自治区林西县大井铜多金属矿床是大兴安岭南段的一个大型 Cu-Sn-Ag-Zn-Pb矿床。该矿床的黄铜矿、黄铁矿、闪锌矿和方铅矿等硫化物的δ34 S值变化为 -1.8‰至 + 3 .8‰ ,平均为 + 0 . 65‰。大约为 -5‰的δ13 C值与峰值为～ + 1‰的δ34 S值的很窄分布表明成矿流体中的碳和硫来源于深部岩浆 ,并且排除了上二叠统林西组地层提供一部分硫和碳的可能性。硫化物矿石的 2 0 6 Pb/ 2 0 4 Pb,2 0 7Pb/ 2 0 4 Pb和 2 0 8Pb/ 2 0 4 Pb比值分别在 18.2 57～ 18.3 68,15.476～ 15.60 9和 3 7.916～3 8.3 55范围内 ,其模式年龄为 12 2～ 2 0 9Ma。黑色页岩含有较高的放射成因铅 ,其 2 0 8Pb/ 2 0 4 Pb比值为 18.473～ 2 0 .156,与矿石完全不同。然而 ,矿石、基性 -超基性岩脉和附近花岗岩体的长石铅中 2 0 6 Pb/ 2 0 4 Pb,2 0 7Pb/ 2 0 4 Pb和 2 0 8Pb/ 2 0 4 Pb比值是相近的 ,它们在 2 0 8Pb/ 2 0 4 Pb-2 0 6 Pb/ 2 0 4 Pb和 2 0 7Pb/ 2 0 4 Pb-2 0 6 Pb/ 2 0 4 Pb图上落在同一条直线上。这条铅同位素混合线两个端元分别为上地幔和造山带 ,即混合了上地幔与前中生代形成的造山带物质。这些证据都强烈地支持了成矿物质来源于深源岩浆。因此 ,大井矿床是一个典型的与次火山岩有关的岩浆 -热液脉型矿床
The Dajing copper polymetallic deposit in Linxi County, Inner Mongolia Autonomous Region is a large Cu-Sn-Ag-Zn-Pb deposit in the southern segment of the Greater Hinggan Mountains. The δ34S values of the sulfide minerals such as chalcopyrite, pyrite, sphalerite and galena in this deposit vary from -1.8 ‰ to +3 .8 ‰ with an average of +0.65 ‰. The very narrow distribution of δ13C values of about -5 ‰ and δ34S values with a peak value of ~ + 1 ‰ indicates that the carbon and sulfur in the ore-forming fluid are derived from deep magmas and that the strata of the Upper Permian Linxi Formation provide Part of sulfur and carbon possibilities. The 20 6 Pb / 2 0 4 Pb, 2 0 7 Pb / 2 0 4 Pb and 2 0 8 Pb / 2 0 4 Pb ratios for sulfide ores ranged from 18.257 to 18.368, 15.476 to 15.60 9 and from 3.7916 to 8.38, respectively 55 range, the model age is 12 2 ~ 290 Ma. The black shale contains a high percentage of radiogenic lead with a 208Pb / 204B ratio of 18.473 to 2.0156, which is quite different from the ore. However, the ratios of 206 Pb / 2 0 4 Pb, 207 Pb / 204 Pb and 208 Pb / 204 Pb in the feldspars of ore, mafic-ultramafic dikes and nearby granitoids are In a similar way, they all fall on the same straight line on the map of 208Pb / 204Pb0-2Pb / 2O4Pb and 207Pb / 204p-2o6Pb / 2O4Pb . The two isotopes of this lead isotope blend line are the upper mantle and the orogenic belt, respectively, which is a mixture of orogenic materials formed by the upper mantle and the previous Mesozoic. All of these evidence strongly support the ore-forming material derived from deep-source magma. Therefore, the Dajing deposit is a typical magmatic-hydrothermal vein type deposit associated with subvolcanic rocks