摘要
肖畈钼(铜)矿床是大别山北缘地区斑岩型钼矿床的典型代表,以发育于花岗斑岩体内、外接触带的细网脉浸染型矿化为特征,并具有以岩体顶部由早期硅化形成的无矿石英核为中心的典型的斑岩热液体系蚀变分带模式。根据矿物组合的不同,将热液成矿期分为早、中、晚3个阶段。流体包裹体研究表明,早、中阶段原生包裹体以CO_2包裹体和气液两相包裹体为主,晚阶段两相包裹体为主,含少量CO_2包裹体。上述三个阶段包裹体均一温度分别为221℃~359℃、158℃~349℃和140℃~266℃,盐度范围分别是2.24%~8.29%、2.07%~9.08%和3.55%~23.68%,表明成矿流体以中低温、低盐度为特征。成矿流体属典型H_2O-CO_2-NaCl体系,流体的沸腾是早、中期金属硫化物大量沉淀的重要机制。中、晚期阶段大气降水混入导致的流体混合及降温作用在成矿过程中发挥了重要作用。初步总结矿床成岩成矿模式为秦岭-大别造山带中生代构造体制转换及其后伸展机制下,下地壳尚未发生拆沉,高压麻粒岩下地壳物质部分熔融形成的肖畈岩体。具体成矿过程为:携带成矿物质上侵冷凝阶段→钾化及初始岩浆热液成矿阶段→大气降水加入的中后期成矿阶段的斑岩型钼矿床。
Xiaofan molybdenum（copper）deposit is a typical representative of porphyry molybdenum deposit in the northern district of Dabie Mountain range,which is located at the inside and outside contact zone of granite-porphyry characterized by fine net-vein disseminated mineralization.The alteration zoning model is a typical porphyry hydrothermal system with the center of ore-free quartz which is formed in early stage at the top of magmatic rock mass.According to the different mineral composition,the hydrothermal mineralization period can be divided into three stages as the early,middle and late stage.The fluid inclusion study shows that in the early and middle stage there are dominated by CO_2 inclusion and gas liquid two-phase inclusion,in the late stage there is dominated by two-phase inclusions with less CO_2 inclusions.The homogenization temperature of the inclusions in the three stages is 221℃-359℃,158℃-349℃and 140℃-266℃individually.The salinity ranges of those inclusions are individually 2.24%-8.29%,2.07%-9.08% and 3.55%-23.68%as well.It is indicated that the ore forming fluid is characterized by the middle to low temperature and low salinity.It is belonged to H_2O-CO_2-NaCl system.The fluid boiling function is an important mechanism for the precipitation of metal sulfides in the early and middle stage.The fluid mixing and cooling function caused by meteoric water in the middle and late stage plays an important role in the mineralization process.Deposit diagenesis metallogenic model can be preliminary summarized as follows.In Qinling-Dabie orogenic belt in the Mesozoic tectonic regime with conversion and rear-stretch mechanism,the lower crust is not in the delamination process.Xiaofan magmatic rock body is formed by partial melting of lower crust of the high-pressure granulite.The specific metallogenic process can be divided into three stages.In the first one,oreforming metallogenic material is rising up and is froze into condensation,in the next stage-initial magma hydrothermal solution of minerali
出处
《矿产与地质》
2017年第2期209-219,共11页
Mineral Resources and Geology
基金
河南省两权价款地质科研项目:豫南大别山区构造-岩浆活动与钼多金属成矿系统研究(任务书编号:豫财招标采购2011-622)资助
