赣北石门寺超大型钨多金属矿床地质特征

赣北石门寺钨矿床为最近查明的大湖塘超大型钨矿床的北矿段。矿体呈似层状、筒状、脉状分布于燕山期酸性花岗岩体上部及与晋宁期黑云母花岗闪长岩外接触带附近。主要工业矿物为白钨矿、黑钨矿、黄铜矿、辉钼矿,矿石组构类型主要有交代结构、固溶体分离结构、脉状构造、浸染状构造及块状构造。常见围岩蚀变有碱性长石化、云英岩化、绿泥石化、硅化,矿床成因类型属岩浆期后热液型。根据矿体特征、矿物组合、矿石组构、矿化分带与围岩蚀变等方面的差异,又可将主要矿体划分为细脉浸染型、热液隐爆角砾岩型和石英大脉型。这3类矿体围绕燕山期酸性花岗岩体共生交织,形成了石门寺“一区三型”钨-铜-钼矿床。石门寺矿区黑云母花岗闪长岩中细脉浸染状白钨矿的发现,改变了以往只专注评价石英大脉型黑钨矿的找矿思路,为矿区及九岭矿集区实现钨矿找矿突破指明了新的方向。

Geological characteristics of Shimensi tungsten polymetallic deposit in northern Jiangxi Province

The ore bodies in the Shimensi deposit are stratiform, pipelike and veinlike in form and occur in the upper part of the Yanshanian acidic granitic body and also along the external contact zone of the biotite granodiorites of late Jinning period. Wolframite, sheelite, chalcopyrite and molybdenite are the main ore minerals. The ore is mainly in crystallization, replacement and solid separation texture and in vein, dissemination, patch and massive structure. The alterations of the host rock are mainly alkali-feldspathization, greisenization, chloritization and silicification. Genetically, the deposit belongs to the postmagmatic hydrothermal W-Cu-Mo deposit. According to characteristics of the ore body, mineral assemblage, ore fabric, metallogenic zoning and host rock alteration, the main ore bodies can be further divided into veinlet-dissemination type, hydrothermal crypto-explosion breccia type and thick-vein type. These kinds of ore bodies which surround the host rock of Yanshanian acidic granite body form the Shimensi "one area-three ore types" tungsten-polymetallic deposit. The prospecting for the veinlet-dissemination type scheelite in the Shimensi deposit changes the previous prospecting which focused only on the thick vein type of wolframite, and provides a new direction for the main breakthrough in the prospecting for tungsten polymetallic ore bodies in the Shimensi deposit and also in the Jiuling ore concentration area.