云南都龙超大型锡锌多金属矿床中闪锌矿微量及稀土元素地球化学特征

云南马关都龙锡锌多金属矿床位于滇东南老君山锡锌钨多金属成矿区南部,是我国三大锡石硫化物矿床之一,目前对其矿床成因认识存在较大分歧。本文采用ICP-MS对都龙矿床中闪锌矿微量元素及稀土元素组成进行分析,以探讨该矿床成矿作用,为甄别已有成因观点提供证据。结果表明,矿床中闪锌矿以富集Fe、Mn、In、Co、Sn和贫Cd、Ga、Ge、Ni等元素为特征,成矿温度属于中—高温,其微量元素组成与白牛厂矿床(与燕山晚期花岗岩有关的矽卡岩型矿床)中的闪锌矿非常相似,和远源矽卡岩型铅锌矿床(核桃坪和芦子园)中闪锌矿存在一定差异,明显有别于喷流沉积型铅锌矿床(云南澜沧老厂和广东大宝山)中闪锌矿。此外,该矿床闪锌矿稀土配分模式多为轻稀土元素富集中等的向右倾斜曲线,以LREE/HREE值高、Eu负异常明显和Ce异常不明显为特征,与矿区燕山晚期隐伏花岗岩稀土元素特征基本一致,成矿物质来源以矿区燕山晚期隐伏花岗岩为主。结合近期矿山开采和地质勘探所揭露的矿化和矽卡岩蚀变的垂向分带等矿床地质特征,认为云南马关都龙锡锌多金属矿床属于与燕山晚期花岗岩有关的矽卡岩型多金属矿床,其中层状矽卡岩的形成应为成矿流体顺层交代的结果,矿化类型和围岩蚀变的分带与隐伏岩体的距离有关。

Trace and Rare Earth Elements Characteristics of Sphalerite in Dulong Super Large Sn-Zn Polymetallic Ore Deposit,Yunnan Province

As one of the three largest Sn-Zn polymetallic ore deposits in China, the Dulong ore deposit is located within the southern Laojunshan Sn-Zn-W polymetallic mineralization province in south-eastern Yunnan.There are conflicts on ore genesis of this deposit.Researches on the trace and rare earth elements of sphalerite in the deposit, by ICP-MS, shows that the sphalerite is characterized by enrichment of Fe, Mn, In, Co, Sn and depleted in Cd, Ga, Ge, Ni, which is similar to that of the Bainiuchang Pb-Zn ore deposit (magmatic hydrothermal type deposit related to Late Yanshanian granite), and certainly different from that of the skarn type Pb-Zn deposit of distant origin (e.g.Hetaoping and Luziyuan, Yunnan), and is quite different from that of the massive sulfide Pb-Zn deposit (e.g.Laochang, Yunnan and Dabaoshan, Guangdong).The chondrite-normalized REE patterns of the sphalerite belong to the LREE-rich type, which are characterized by the higher LREE/HREE ratio, the obvious negative anomaly of Eu and the unconspicuous anomaly of Ce, corresponding to that of Late Yanshanian concealed granite.Research data in this paper show that, in this deposit, the ore-forming materials mainly came from the granite and the ore-forming temperature belongs to the medium-high temperature.In consideration of the vertical mineralization zoning and skarn alteration zoning, it is suggested that the Dulong Sn-Zn polymetallic ore deposit is a skarn type related to the Late Yanshanian granite, and the zoned mineralization and wall-rock alteration are controlled by the distance between the deposit and the concealed intrusion.