胶东半岛夏甸金矿床热液绿泥石矿物学特征及其对流体演化的指示意义  

The Mineralogy Characteristics of Hydrothermal Chlorites of Xiadian Gold Deposits in Jiaodong Peninsula and Its Implication on Fluid Evolution

作　　者：夏侯立超 毛先成[1] 马驷 

机构地区：[1]中南大学地球科学与信息物理学院,湖南 长沙

出　　处：《地球科学前沿（汉斯）》2020年第7期593-615,共23页Advances in Geosciences

摘　　要：夏甸金矿床为典型的受构造控制的热液矿床,断层两侧围岩广泛发育大规模的热液蚀变,绿泥石可见于各类蚀变带中,与各期次流体具有紧密的联系。本文根据绿泥石的伴生矿物,划分了绿泥石的形成期次,使用电子探针分析了绿泥石中的主量元素,基于Si、Fe、AlIV、AlVI、Mg、Fe/(Fe + Mg)等参数,区分了变质成因和热液成因绿泥石,并讨论了各阶段离子置换作用对绿泥石的影响,以及绿泥石组分对于热液流体的指示意义。结果显示,从早期到晚期,绿泥石反映了热液流体酸性、温度下降,氧逸度升高的特征,并在此基础上区分出可能存在的两期热液事件。The Xiadian gold deposit is a typical fault controlled hydrothermal deposit, with widespread hy-drothermal alteration along the wallrock around the fault. Chlorite is found present in all kinds of alteration belt, which has a close relationship with the fluid of each stage. In this paper, we divided the forming stage of chlorite firstly by its co-existing mineral, and used the Electronic Micro Probe Analyses (EPMA) to analyze the major element in chlorite. Based on Si, Fe, AlⅣ, AlⅥ, Mg, Fe/(Fe + Mg), we separate the metamorphic chlorites from hydrothermal chlorites, and discussed the impact of cation substitutions on chlorite among different stage and the implication of the chlorite’s compositions on hydrothermal fluid. The result shows that, from early stage to late, the chlorites have indicated the fluid with a decreasing acidity, and temperature and increasing oxygen fugacity. We found a possible two-stage hydrothermal events based on the hydrothermal chlorites’ characteristics.

关 键 词：胶东半岛 夏甸金矿床 热液蚀变 绿泥石化 地球化学 

分 类 号：P61[天文地球—矿床学]