新疆民丰县卧龙岗锑矿地质特征及成因探讨

Geological feature and genesis discussion of Wolonggang antimony deposit in Minfeng County of Xinjiang

卧龙岗锑矿是近年来在昆仑造山带新发现的一处中型锑矿,矿体主要赋存于二叠系黄羊岭组的岩屑砂岩、泥质粉砂岩、粉砂质泥岩、泥岩中,主要受断裂构造、节理及破碎带控制。在对卧龙岗锑矿进行野外地质勘查基础上,开展了含矿石英脉的流体包裹体特征、氢氧同位素及硫同位素特征研究。流体包裹体岩相学和显微测温结果表明,卧龙岗锑矿主要发育简单的气液两相型流体包裹体,包裹体的均一温度范围为143℃~228℃,包裹体盐度w(NaCleq)为1.7%~5.8%。稀土元素和微量元素示踪结果分析表明,成矿金属物质来源于二叠系黄羊岭组。稳定同位素研究表明,成矿期的石英的δ18O和δD分别为8.4‰~11.4‰和-65.15‰~-59.74‰,成矿流体主要来自天然降水,可能受岩浆水和变质水的影响。硫化物δ34S值分布在-13.0‰~5.7‰之间,硫成因较为复杂,辉锑矿中的硫为多来源的。该矿床成因类型属于中低温浅成热液充填型锑矿床。

Wollongang antimony deposit is a medium-scale antimony deposit newly discovered in the Kunlun orogenic belt in recent years.The orebodies are mainly hosted in lithic sandstone,argillaceous siltstone,silty mudstone and mudstone of Permian Huangyangling Formation,which are mainly controlled by the fault structures,joints and fractured zones.Based on the geological field exploration in Wollongong antimony deposit,the characteristics of fluid inclusion,hydrogen,oxygen and sulfur isotopes of ore-bearing quartz veins are studied.The petrographic and microthermometry result of fluid inclusion shows that there are mainly simple gas liquid two-phase type fluid inclusions in Wollongang antimony deposit.The homogeneous temperature range of the inclusions is 143℃-228℃.The salinity range w(NaCleq)is 1.7%-5.8%.The tracer analysis result of rare earth elements and trace elements shows that the metallogenic metals originate from Permian Huangyangling Formation.The stable isotopic study result indicates thatδ18O andδD of quartz in the metallogenic period are 8.4‰-11.4‰and-65.15‰--59.74‰,respectively.The metallogenic fluids mainly come from natural precipitation,which might be affected by magmatic water and metamorphic water.The range ofδ34S value of sulfides is-13.0‰-5.7‰,the origin of sulfur is complex,and the sulfur in stibnite comes from multiple sources.The genetic type of this deposit belongs to the medium-low temperature epithermal filling type antimony deposit.