氧、硫逸度对岫岩红旗铅锌矿床矿物组合共生分异的制约

基于野外调查和镜下鉴定，通过计算岫岩红旗铅锌矿床主要矿物在不同温度T下的氧逸度f_O▲2和硫逸度f_S▲2，绘制出Fe-Pb-Zn-Cu-O-S体系热力学lgf_O▲2-lgf_S▲2参数状态图.研究该区矿物共生组合的控制因素及其形成的物理化学条件，为解决辽吉成矿带同类型矿床成矿流体演化提供参考.结果表明，T，fo₂，fs₂是使成矿元素沉淀、金属矿物组合共生分异的重要因素.fo₂，fs₂控制着矿物的稳定区间，闪锌矿较大的稳定范围，使它在方铅矿、黄铁矿沉淀之后仍可运移沉淀；温度降低使矿物形成所需的最低lgfo₂，lgfs₂减小，因此降温更利于成矿；构造破碎带为流体提供了运移通道，同时也是良好的地球化学障.在实际找矿过程中，断裂构造、铁帽、中低温蚀变发育的地方值得重视.

Constraints of fO▲2 and fS▲2 on the Paragenesis and Separation of Mineral Assemblages in Hongqi Pb-Zn Deposit， Xiuyan

Based on field investigation and microscopic mineral identification results， the thermodynamic lgfo₂-lgfs₂ parameter state diagrams of Fe-Pb-Zn-Cu-O-S system were plotted by calculating the oxygen-sulfur fugacity of main minerals in Hongqi Pb-Zn deposit， Xiuyan， at different temperatures. The controlling factors and physicochemical conditions of minerals paragenesis were studied to provide a reference for solving the ore-forming fluid evolution of the same type of deposits in the Liaoji metallogenic belt. The results indicated that T， fo₂， fs₂ are key factors for the precipitation of ore-forming elements and the paragenesis of mineral assemblage. The large stable range of sphalerite is controlled by fo₂， fs₂， making Zn⁺ still transportable after galena and pyrite precipitation. Cooling is conducive to mineralization because the minimum lgfo₂， lgfs₂ formed by minerals decrease when the temperature is lowered. The tectonic fracture zone provides a migration channel for fluid， and it is also a good geochemical barrier. In prospecting process， it is important to pay special attention to the places with fault structure， gossan and medium-low temperature alterations.