桓仁夕卡岩型多金属矿床地质特征与流体包裹体研究

桓仁夕卡岩型多金属矿床位于辽东裂谷北部边缘与太子河凹陷复合部位, 产于燕山晚期侵入闪长杂岩与寒武纪沉积灰岩接触带间的夕卡岩内。夕卡岩矿物可以分为进变质阶段蚀变矿物组合和退变质阶段蚀变矿物组合, 成矿元素由深部向浅部具有Fe→Cu（Mo）→Zn→Pb 的转换规律, 具有明显的分带分段性。为了探讨成矿流体的物理化学性质及其演化史, 选择了石榴子石和方解石中的气液两相流体包裹体进行研究。数据测试表明, 石榴子中流体包裹体的均一温度范围为376.1~450.0 ℃, 平均411.6 ℃; 方解石中流体包裹体的均一温度范围为122.6~170.0 ℃和178.3~270.2 ℃, 平均值分别为149.5 ℃和204.5 ℃, 冰点温度范围为？4.2 ~ ？17.6 ℃, 与前人研究成果相吻合, 与国内外其他夕卡岩矿床相比, 数据具有实际和理论研究意义。本矿床Fe-Cu（Mo）、Cu-Zn、Zn-Pb 矿体的形成温度分别集中于约410 ℃、400~300 ℃、约150 ℃和约200 ℃。以往Pb、S 和D-O 地球化学数据和本次研究REE 特征显示, 岩浆流体起源于上地幔, 在上升过程中携带了大量成矿物质, 在进变质阶段和退变质阶段, 成矿流体交代形成特定的夕卡岩矿物组合, 退变质阶段的后期阶段, 有了大气降水的参与, 单一来源的岩浆流体转化为了混合流体。

Geological characteristics and fluid inclusions of Huanren skarn polymetallic deposit

Huanren skarn polymetallic deposit, hosted by skarn contact belt between Cambrian limestone and late Yanshanian diorite complex, is located in conjuction of northern part of Liaodong Rift and Taizihe Depression.Typically, skarn minerals are characterized by two main alteration styles： early prograde assemblage and later retrograde assemblage, and there is an obvious change in ore elements from Fe→Cu （Mo） to Zn→Pb upwards. In order to understand physicochemical properties and evolution history of ore-forming fluids, vapor-liquid fluid
inclusions from garnet and calcite were studied. The data show that temperatures of homogenization for garnet fluid inclusions range from 376.1 to 450.0 ℃, with an average of 411.6 ℃; whereas those for calcite fluid inclusions range from 122.6 to 170.0 ℃ and 178.3 to 270.2 ℃, with averages of 149.5 ℃ and 204.5 ℃ respectively. Temperatures of final ice melting range between ？4.2 and ？17.6°C. All data we determined are consistent with those of former researcher and are of theoretical and practical significance in comparison with that
of other skarn deposits. Based the above, we proposed that ~410 ℃, 400~300 ℃, ~150 ℃ and ~200 ℃ are main ore-forming temperatures of Fe-Cu （Mo）, Cu-Zn and Zn-Pb ore bodies, respectively. Old Pb, S and D-O geochemical data and new REE data indicate that magmatic fluid originates in the upper mantle and carries plentiful ore-forming materials in migration, meteoric water may be involved during later skarn retrograde stage.