滇中郝家河砂岩型铜矿床成矿作用过程的流体包裹体证据

THE EVIDENCE FROM FLUID INCLUSIONS FOR ORE FORMING PROCESS IN HAOJIAHE SANDSTONE-TYPE COPPER DEPOSIT,CENTRAL YUNNAN PROVINCE

通过对牟定郝家河砂岩型铜矿床的不同结构构造及矿化类型岩石中矿物包裹体特征的研究及对比,认为不同结构构造及矿化类型岩石的形成与不同成岩-成矿阶段流体的演化特点密切相关。流体包裹体测温数据表明其成矿作用主要经历3个成矿流体演化阶段：成岩期（均一温度：84℃~162℃）、主改造期（均一温度：145℃~227℃）及次改造期（均一温度：129℃~177℃）。3期流体的盐度变化不大,多处于4%~10%之间,而它们的气相成分主要为H2O,其次为CH4和CO2。成岩期流体演化形成了砂岩铜矿的初始矿源层及贫矿体,矿化程度高的地方甚至形成浸染状或纹层状矿石;改造-成矿期的流体则在原来基础上进一步演化形成现今受构造控制的条带状、脉状富矿体。

The study and comparison of fluid inclusions with different texture,structure and mineralization intensities in the Haojiahe copper deposit in Yunnan Province revealed that their formation is closely related to the evolution of ore-forming fluids in different rock forming and ore forming stages.Three stages of ore-forming fluid are recorded during the formation of copper deposit.First is the rock-forming period（Th-homogeneous temperature：84 ℃～162 ℃）,second is the main reworked period（Th：145 ℃～227 ℃） and the last is the secondary reworked period（Th：129 ℃～177 ℃）.The salinity（NaCl） of fluid inclusions of these three stages ranges from 4% to 10%,the gaseous phase of fluid inclusions were mainly composed of H2O,and the minor compositions contained CH4 and CO2.Ore source bed and some lean ore bodies of this sandstone-type copper deposit formed by the evolution of fluid during the rock-forming period,at the place of highly mineralization degree can even form disseminated or lamellar ores.Reworking mineralization fluid was the further evolution on the base of the rock-forming period fluid,which formed the final ore body controlled by structure and some banded or vein rich ores.