滇东南官房钨矿床与南秧田钨矿床地质特征对比研究

Comparative Study on Geological Features of the Guanfang and Nanyangtian Tungsten Deposit in Southeastern Yunnan Province, China

滇东南地区是我国一个重要的钨、锡、银、铜、铅、锌、锰等金属成矿密集区,环绕两个燕山期花岗岩体边缘及外围分布有多处有色金属矿床,其中官房钨矿床和南秧田钨矿床是该区较为典型的两个大型钨矿床,分别位于薄竹山岩体西南缘接触带上和老君山岩体东侧约5 km的区域变质岩相带中。本文在前人研究的基础上,通过两个矿床成矿岩体和矿床地质特征的详细对比研究,表明这两个矿床具有相似的成矿母岩,相同的大地构造成矿背景,类似的矿田构造,相似的矿体产出特征及矿石特征;两个矿床的不同之处主要表现在控矿构造、赋矿围岩、矿化分带及围岩蚀变等几个方面。对这两个钨矿床成因进行简要探讨,表明官房钨矿床属于接触交代型白钨矿床,而南秧田钨矿床则属于多因复成矿床,经历过加里东期热水沉积-印支期区域变质-燕山期热液叠加成矿这一复杂的过程。

Southeastern Yunnan is an important ore-concentrated area for tungsten, tin, silver, copper, lead, zinc, manganese and other metals. There are many non-ferrous metal deposits surrounding the margin and periphery of two Yanshanian granites. The Guanfang and Nanyangtian tungsten deposit are the typical large tungsten deposits in this area, which respectively located in the contact zone on the southwest edge of Bozhushan granite and the metamorphic facies east 5 km of Laojunshan granite. On the basis of the previous research, this paper conducts a detailed comparative study on the metallogenic rock and geological features of the two deposits, showing the similar metallogenic host rock, the same geotectonic metallogenic background, the similar ore field structure, the similar ore bodies and ore characteristics. The differences between the two deposits are mainly in the aspects of ore-controlling structure, host surrounding rock, mineralization zone, wall rock alteration and so on. A brief discussion on the genesis of the two tungsten deposits demonstrates Guanfang tungsten deposit belongs to the contact account type scheelite deposit, while Nanyangtian tungsten deposit belongs to the composite deposit which has experienced a complex process of mineralization, namely Caledonian hydrothermal sedimentary-Indo regional metamorphic-yanshanian hydrothermal overprinting.