| 论内蒙古别鲁乌图铜硫多金属矿床的火山热液成因 |
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| 引用本文：.1990.On the volcano-hydrothermal origin of the Bieluwutu copper-sulfur polymetallic deposit，Inner Mongolia[J].Mineral Deposits,9(4):339~351 |
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| 中文摘要:本文从矿床成矿地质环境角度，着重讨论了内蒙古别鲁乌图铜硫多金属矿床地质地球化学特征及其与火山岩的成因联系，确定了该矿床成矿作用时、空演化和成矿元素富集特点。研究表明：火山热液沉积是矿床形成的主导控制因素，区域变质是成矿后热液叠加的重要地质营力，矿床属海相火山岩型块状硫化物矿床，另外，矿区范围内首次发现的电气石岩不仅是典型的火山热液沉积岩，而且是一有效的近矿找矿标志。 |
| 中文关键词:火山热液 成矿作用 矿化分带 电气石岩 内蒙古别鲁乌图 |
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| On the volcano-hydrothermal origin of the Bieluwutu copper-sulfur polymetallic deposit，Inner Mongolia |
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| Abstract:Located on the southern flank of the Late Hercynian Wanduermiao anticlinorium, the Beiluwlatu ore deposit is one of the most important copper-sulfur-lead-zinc-silver sulfide deposits in the northern marginal polymetallogenic belt of the North China platform. The ore deposit occurs mainly within Upper Carboniferous volcano-sedimentary sequence of Amushan Group, in which massive, disseminated, banded and stockwork pyrite, pyrrhotite and chalcopyrite ores constitute an inseparable part of the strata. The upper Carboniferous volcano-sedimentary rocks of Amushan Group in the ore district can be divided into five lithological associations: ① tuffaceous siltstone, siliceous nodule-bearing siltstone and limestone lenticules; ② hydrothermal sediments (chlorire-K-feldspar-quartz and chlorite-albite-quartz), banded tourmalinite and laminated gossans; ③ stratifiied rhyodacite and tuffaceous siltstone; ④ copper-sulfur polymetallic orebody; and ⑤ tuffaceous siltstone, greywacke and conglomeratic sandstone. Both chemical and electron microprobe analyses show that tourmaliae from the banded tourmalinite is dravite which shows no difference from other tourmaline associated with submarine exhalative ores. Lead isotopic composition of the ore deposit varies to a certain extent: 206Pb/204Pb= 17.961-18.421, 207Pb/204Pb=15.526-15.833 and 208Pb/204Pb= 38.012-38.730. Four of the calculated model ages are older than 360 Ma, ranging from 399 to 481 Ma, whereas two are consistent with or close to ages of the wail rocks (279-321 Ma). The 232Th/238U, Th/U and μvalues of lead provenance are 4.40-4.17, 3.88-4.0 and 9.37-9.92 respectively. It is considered that lead of the Bieluwutu deposit is derived from heterogeneous mixture of the lower crust and the upper mantle.δ34S values of various sulfides are relatively stable (+0.2-+5.8‰). δ18O values of quartz are +6.94-+14.5‰ for massive sulfide ores and wall rocks. δDH2O values of fluid inclusions in quartz are -54一-67‰ for sulfide ores and -98‰for wall rocks. In addition, δ13C values of calcite range from -4.5 to -6.5‰. The variation range of stable isotopic data together with the behavior of minor elements in sulfide minerals implies that sulfur, oxygen, hydrogen, carbon and minor metallic elements are largely derived from volcano-hydrothermal eruption. REE content is 40.86 ppm for disseminated copper ores underlying the main orebody, 13.03 ppm for massive or banded sulfide ores from the main orebody and 114.95 ppm for disseminated copper-lead-zinc ores from theupper part of the deposit. Studies reveal that REE patterns are principally controlled by REE composition of ore-forming fluids and physicochemicsl conditions for ore deposition. Based on our data combined with geological setting of the ore deposit, It is thought that the Bieluwutu ore deposit is a product of Late Carboniferous submarine volcano-sedimentation, belonging hence to volcanogenic massive sulfide type formed in ancient epicontinental rift. |
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