赣西北香炉山钨矿床地质特征与找矿标志

Geological Characteristics and Prospecting Criteria of Xianglushan Tungsten Deposit,Northwestern Jiangxi Province

香炉山钨矿床是一个超大型矽卡岩型白钨矿床,矿体主要赋存在北东向香炉山背斜核部的燕山晚期花岗岩与中寒武统杨柳岗组不纯灰岩的接触带中。花岗岩中W含量超过50×10-6,矿石硫化物的δS34平均值为+3.4‰,成矿作用主要发生在夕卡岩阶段,其次为硫化物阶段。主要的成矿控制因素为:背斜及其伴生的层间滑脱构造、富含W的S型花岗岩以及中寒武统的不纯灰岩;主要的围岩蚀变为:夕卡岩化、角岩化、硅化、云英岩化、绿泥石化和萤石化;这些围岩蚀变和黄铁矿化、白钨矿化、黑钨矿化及其氧化产物都是直接的找矿标志。

Xianglushan Tungsten Deposit is a super-large skaru-type scheelite deposit. The major ore bodies of this deposit are found in the contact zone between a Late Yanshanian granite body and the impure limestone of the Middle Cambrian Yangliugang Formation which makes the core of the Xianglushan Anticline. The W contents in the granite are over 50×10^-6. The average δS^34 value of ore is ＋3.4‰. The ore formation process mainly occurred in the skarn stage, and in a lesser amount in the sulfide stage. The major ore-forming controlling factors are anticline structure with its accompanied interlayer slipping planes, S type granite with higher W concentration, and Middle Cambrian impure limestone country sediments. The major hydrothermal alterations are skarnization, hornfelsization, silicification, greisenization, chloritization and fluoritization. These hydrothermal alterations and pyritization, sheelitization, wolframitization and their oxidation products are direct ore prospecting criteria.