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胶东邢家山矽卡岩型钼矿床成矿流体与成矿机制
Ore-forming fluids and metallogenic mechanism of the Xingjiashan skarn Mo deposit in Jiaodong,China
【摘要】 邢家山矿床是胶东地区发现的大型矽卡岩型钼多金属矿床。通过野外调研,将成矿过程划分为四个阶段:早矽卡岩阶段、晚矽卡岩阶段、石英硫化物阶段和石英-碳酸盐阶段。对不同阶段流体包裹体研究表明,存在液体包裹体(L)、气体包裹体(V)和含子矿物包裹体(S)三类。激光拉曼探针显示流体的气体分类型为H2O-H2S,早和晚矽卡岩阶段均一温度集中在375~450℃,盐度存在14%~15%NaCleqv和大于30%NaCleqv两个端元;石英-硫化物阶段均一温度集中在260~340℃,盐度存在8%~12%NaCleqv和大于50%NaCleqv两个端元;石英-碳酸盐阶段流体包裹体均一温度集中在170~200℃,盐度小于10%NaCleqv。该矿床成矿流体具有高温高盐度的特征,且富含H2S等还原性气体,从矽卡岩阶段到碳酸盐阶段成矿温度和盐度总体有降低的趋势。邢家山钼矿δ18 OH2O值为0.04‰~8.18‰,δ13 CV-PDB值为-3. 35‰~-0.73‰,δ18 OV-SMOW值为5. 93‰~8. 42‰,δ34S值为6.5~10. 8‰。邢家山矿床成矿流体主要来源于岩浆,后期有大气降水的加入,流体沸腾是成矿的主要机制。
【Abstract】 The Xingjiashan Mo deposit is currently a large skarn deposit in the Jiaodong metallogenic province. The hydrothermal activities of mineralization can be divided into four stages : early skarn stage(Ⅰ),late skarn stage(Ⅱ), quartz-sulfide mineral stage(Ⅲ) and quartz-carbonate stage(Ⅳ). The characteristics of the fluid inclusions show that the inclusions can be divided into three types : liquid-rich inclusions(L),vapor-rich inclusions(Ⅴ) and daughter mineral-rich inclusions(S). The results of Roman spectra study show that the volatile phases have H2 S. In the early and late skarn stages, the homogenization temperatures peak value range from 375℃ to 450℃,and the salinities have two ranges 14% ~15% NaCleqv and >30% NaCleqv. In quartz-sulfide mineral stage,the homogenization temperatures peak value range from 260℃ to 340℃,and the salinities have two ranges 8% ~10% NaCleqv and>50% NaCleqv. In quartz-carbonate mineral stage,the homogenization temperatures peak value range from 170℃ to 200℃, and the salinities ranges 8% ~10% NaCleqv and >50% NaCleqv. The values of δ18 OH2 O,δ13 CV-PDB,δ18OV-SMOW and δ34S are 0.04‰~8. 18‰,-3. 35‰~-0.73‰,5. 93‰~8.42‰ and 6. 5‰~10. 8‰.These results indicate that the ore-bearing fluid in the early stage is characterized by high temperature and high salinity. The ore-forming fluids are mainly derived from magma. Magma water is major ore-forming fluid, with minor meteoric water in the late stage. Fluid boiling may be the mechanism of large-scale metallogenic precipitation.
【Key words】 Fluid inclusion; Skarn deposit; C-H-O-S isotopes; Ore-forming fluid; Xingjiashan Mo deposit;
- 【文献出处】 岩石学报 ,Acta Petrologica Sinica , 编辑部邮箱 ,2019年05期
- 【分类号】P618.65
- 【被引频次】4
- 【下载频次】256