云南老厂火山岩型银铅锌铜矿床地质特征及成因

云南老厂银铅锌矿床为富银和铅的锌－铅－铜型块状硫化物矿床，主要产于偏碱性的中基性火山岩系中．矿床由３层矿体组成：上部碳酸盐岩中裂隙脉状银铅锌矿体；中部火山岩中似层状银铅锌矿体；深部（次）火山岩中不规则状铜硫矿体．矿石结构构造表现为含矿气水溶液的充填交代成矿作用，矿石铅、硫、氢氧同位素组成反映了成矿物质主要来源于燕山晚期－喜山早期的深源原始岩浆热液．根据火山岩时代为主要晚二叠世－三叠纪，其次为白垩纪－老第三纪的最新研究成果，且后者主要以次火山岩出现，提出矿床成因属燕山晚期－喜山早期的火山－次火山热液充填交代成矿，从而统一了长期以来该矿床火山成矿与燕山晚期－喜山早期成矿的矛盾．

GEOLOGICAL CHARACTERISTICS AND GENESIS OF LAOCHANG VOLCANIC-HOSTED SILVER,LEAD,ZINC AND COPPER DEPOSIT IN YUNNAN

Laochang volcanic-hosted silver, lead, zinc and copper deposit in Yunnan is located in an active tectonic zone. The ore-bearing volcanic rock system is weak-alkalic intermediate-basic volcanic rocks. The ore deposit consists of three layer orebodies: fissure vein-shaped silver, lead and zinc orebodies in upper carbonate rocks; stratiform silver, lead and zinc orebodies in middle volcanic rocks, inregular shaped copper and sulphur orebodies in deep volcanic or subvolcanic rocks. Ore fabrics displays filling and replacement metallization of ore-bearing hydrothermal solution. Ore isotopic composition of lead, sulphur, hydrogen and oxygen reflects metallogenic materias mainly derived from deep primitive magmatic hydrothermal solution of Later Yanshan period-Early Xishan period. Predecessors for genesis of Laochang ore deposit put forward some viewpoints of intermediate-basic volcanic hydrothermal metallization in Early Carboniferous period,oncealed granite hydrothermal metallization in Yanshan period, and superposition metallization of above two hydrothermal solutions, and so on. On the basis of comprehensively considering each geological characteristic of ore deposit and recent studied achievement of volcanic age, the author considers that the genetic type of Laochang ore deposit belongs to volcanic-subvolcanic hydrothermal filling and replacement ore deposit.