河南小池沟金矿床硫铅同位素组成及成矿物质来源
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摘要
小池沟金矿床位于秦岭造山带熊耳山变质核杂岩构造中段。通过对该矿床主成矿阶段形成的蚀变岩型矿石中硫、铅同位素分析,获得矿床硫同位素δ~(34)S值为-3.05‰～10.93‰,多数位于陨石硫范围内,表明硫主要来源于地幔,并有地壳硫加入,反映了地幔硫遭受地壳物质混入后的硫同位素组成;铅同位素~(206)Pb/~(204)Pb值为17.09～17.53,~(207)Pb/~(204)Pb值为15.31～15.61,~(208)Pb/~(204)Pb值为37.20～38.10,变化范围均不大,属于正常铅范围。铅同位素特征参数及相关图解显示矿石铅具壳幔混合特征。硫、铅同位素组成表明,该矿床的成矿物质以幔源为主,为深部幔源物质混合了壳源物质。
Xiaochigou Gold Deposit is located in the middle of Xiongershan metamorphic core complex in Qinling orogenic belt.Based on the analysis of sulfur and lead isotopes in altered rock type ores formed in the main metallogenic stage of the deposit,it is found that theδ~(34)S of sulfur isotope of the deposit is between-3.05‰ and 10.93‰,mostly remaining within the range of meteorite sulfur,indicating that the sulfur mainly comes from the mantle with the addition of crustal sulfur,which reflects the sulfur isotopic composition of mantle sulfur after being mixed with crustal materials.The lead isotope~(206)Pb/~(204)Pb value is 17.09-17.53,~(207)Pb/~(204)Pb value is 15.31-15.61,and~(208)Pb/~(204)Pb value is 37.20-38.10.The variation range is not wide,belonging to normal lead range.Lead isotopic characteristic parameters and related diagrams show that the lead in ores has crust-mantle mixing characteristics.The sulfur and lead isotope compositions show that the ore-forming materials of the deposit are mainly mantle-derived materials,and the deep mantle-derived materials are mixed with crust-derived materials.
Xiaochigou Gold Deposit is located in the middle of Xiongershan metamorphic core complex in Qinling orogenic belt.Based on the analysis of sulfur and lead isotopes in altered rock type ores formed in the main metallogenic stage of the deposit,it is found that theδ~(34)S of sulfur isotope of the deposit is between-3.05‰ and 10.93‰,mostly remaining within the range of meteorite sulfur,indicating that the sulfur mainly comes from the mantle with the addition of crustal sulfur,which reflects the sulfur isotopic composition of mantle sulfur after being mixed with crustal materials.The lead isotope~(206)Pb/~(204)Pb value is 17.09-17.53,~(207)Pb/~(204)Pb value is 15.31-15.61,and~(208)Pb/~(204)Pb value is 37.20-38.10.The variation range is not wide,belonging to normal lead range.Lead isotopic characteristic parameters and related diagrams show that the lead in ores has crust-mantle mixing characteristics.The sulfur and lead isotope compositions show that the ore-forming materials of the deposit are mainly mantle-derived materials,and the deep mantle-derived materials are mixed with crust-derived materials.
引文
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[2]姚改委.小池沟金矿区深部找矿前景分析[J].现代矿业,2013(5):51-53.
[3]OHMOTO H.Systematics of sulfur and carbon isotopes in hydrothermal ore deposits[J].Economic Geology,1972,67:551-578.
[4]DEINES P,HARRIS J W.Sulfids inclusion chemistry and carbon isotopes of Africa diamonds[J].Geochimica et Cosmochimica Acta,1995,59(15):3 173-3 188.
[5]温春齐,多吉.矿床学研究方法[M].成都:四川科学技术出版社,2009:170-174.
[6]ZARTMAN R E,DOE B R.Plumbotectonics-the model[J].Tectonophysics,1981,75(1/2):135-162.
[7]朱炳泉,李献华,戴橦谟,等.地球科学中同位素体系理论与应用---兼论中国大陆壳幔演化[M].北京:科学出版社,1998:224-226.