| 铜陵地区老鸦岭层状钼矿床铅同位素组成研究 |
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| 引用本文：.2004.Lead Isotope Study of Laoyaling Stratiform Mo Deposit in Tongling Area[J].Mineral Deposits,23(4):422~430 |
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| 基金项目:国家重点基础研究发展规划项目“大规模成矿作用与大型矿集区预测(G1999 043201)” |
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| 中文摘要:安徽铜陵老鸦岭矿床中二叠系大隆组(P2d)顶部的含矿(钼矿化) 黑色页岩以及附近(立新煤矿)同一层位不含矿黑色页岩的实测铅同位素组成分别为：20 6Pb/204Pb 20.20～22.37，207Pb/204Pb 15.67～15.82，208Pb/204Pb 38.47～38.60和206Pb/204Pb 18.83～20.80，207Pb/204Pb 15.65～15.76，208Pb/204Pb 38.84～39.22。对137 Ma的 放射成因Pb进行校正后的铅同位素组成表明，含矿黑色页岩和不含矿黑色页岩均与燕山晚期火成岩无关，老鸦岭含矿黑色页岩可能具沉积成因。对沉积(约250 Ma)以来的放射成因Pb进 行校正后的铅同位素组成表明：不含矿黑色页岩的Pb源自上地壳，而含矿黑色页岩的Pb(因 而推测其他成矿金属)可能源于上地壳物质(与不含矿黑色页岩的Pb源相似)与下地壳物质的混合。 |
| 中文关键词:地球化学 铅同位素 黑色页岩 老鸦岭矿床 铜陵地区 |
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| Lead Isotope Study of Laoyaling Stratiform Mo Deposit in Tongling Area |
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| Abstract:The Pb isotopic compositions of Mo_bearing black shale of Dalong Formation (P2d) from the Laoyaling deposit in the middle_lower Yangtze valley were determ ined.206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios vary from 20.20 to 22.37, from 15.67 to 15.82 and from 38. 47 to 38.60, respectively. In contrast, the corresponding Pb isotopic ratios of the non_mineralized black shale from the Lixin coal mine near the Laoyaling dep osit are in the ranges of 18.83～20.80, 15.65～15.76 and 38.84～39.22 respective ly. The Pb isotopic compositions corrected for 137 Ma radiogenic Pb show that Pb isotopic compositions of the Laoyaling mineralized black shale and the Lixin no n_mineralized black shale are significantly different from those of the feldspar s from Late Yanshanian igneous rocks in the area. Pb isotopic compositions and o re textures suggest that Pb of the black shale from the Laoyaling deposit is not derived from the Yanshanian intrusive rocks, and that the Laoyaling Mo deposit is a typical sedimentary deposit hosted by the black shale. The Pb isotopic comp ositions corrected for 250 Ma (approximate age of the Dalong Formation) radiogen ic Pb show that the Pb source of the non_mineralized black shale is upper crusta l material and the Pb of the Mo_bearing black shale of the Laoyaling deposit is very likely a mixture of the Pb from upper crustal material shared by non_minera lized black shale and the Pb from the lower crust. |
| keywords:geochemistry, Pb isotopes, black shale, Laoyaling deposit, Tongling area |
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