滇东南都龙锡锌多金属矿床一种新的铜矿化类型

A New Type Copper Mineralization in Dulong Sn-Zn Polymetallic Deposit, Southeast Yunnan Province, China

都龙锡锌超大型矿床是中国第三大锡石硫化物矿床。矿区内铜矿化除主要的夕卡岩型、石英-萤石脉型外,近期的勘查工作还在曼东矿段南部揭露了燕山晚期花岗斑岩内的铜矿化,不少达到了工业要求,是该矿区内新发现的一种铜矿化类型。该类矿化以铜为主,共-伴生锡、锌等,矿体受花岗斑岩脉规模以及贯通岩脉与围岩的构造裂隙控制,具收缩膨胀、分支复合、尖灭再现等现象。成矿元素分布特征指示铜、锡等成矿物质主要来源于燕山晚期第三期岩浆活动。含矿花岗斑岩LA-ICPMS锆石U-Pb定年,获得成岩-成矿年龄为88 Ma。上述研究结果表明,该类矿化具有比较典型的岩浆热液成矿特征。与夕卡岩型、石英-萤石脉型相比,该类型铜矿化具有成因明确、找矿标志明显、空间分布范围确定的优点。曼东矿段及其周边,具有黑云母等暗色矿物含量较高、结晶程度稍差、蚀变及破碎程度较强等特点的燕山晚期花岗斑岩是有利的找矿对象。

Dulong Sn-Zn deposit is the third largest cassiterite-sulfide deposit in China. Beside Skarn and quartz-fluorite vein types, a new type of copper mineralization associated with Sn and Zn, which hosted in later Yanshanian granite-porphyry, were recently found in Mandong mining domain. This type ore bodies as nets, lentoid and quasi strata form, are controlled by granite-porphyry and the fractures intercommunicated to wall-bed rocks. The characteristics of mineralization elements in typical drills indicate that Cu, Sn, and etc., should derived from later Yanshanian granite-porphyry. LA-ICPMS U-Pb dating of Zircon from ore-hosted granite-porphyry suggests the age of ～88 Ma with the magmatism and ore-forming event. These studies mention above suggest that this type of copper mineralization should related to later Yanshanian magmatic hydrothermal. Contrasted to Skarn and quartz-fluorite vein types, the granite-porphyry type of copper mineralization has virtues with clear genesis, exploration indicators and distribution. Future explorations around later Yanshanian granite-porphyry are favorable with rich-mica, poor crystallization, and stronger alteration and broken in Mandong mining domain and surrounding areas.