赣西北石门寺钨矿似斑状黑云母花岗岩的控矿作用及找矿意义  

Ore-controlling Role of Porphyraceous Biotite Granite in Shimensi Tungsten Deposit and Its Prospecting Significance

作　　者：彭花明[1,2,3] 袁琪[2] 李秋耘[3] 刘富军[2] 张博譞[2] 但小华 张中山 董晓峰 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]东华理工大学省部共建核资源与环境国家重点实验室培育基地,南昌330013 [3]中国地质科学院地质研究所,北京100037 [4]江西地质矿产局赣西北地质大队,九江332000

出　　处：《科学技术与工程》2016年第3期135-142,共8页Science Technology and Engineering

基　　金：国家科技支撑计划项目(2011BAB04B02);中国地质调查局项目(1212011220248);教育部核资源与环境重点实验室开放基金项目(NRE1209)资助

摘　　要：赣西北武宁县石门寺钨矿是大湖塘世界级超大型W-Cu-Mo多金属矿集区的重要组成部分,其钨资源量占矿集区钨资源总量的67%,其中细脉浸染型钨矿体占矿区钨矿总储量的74%,是矿区最重要的矿化类型。石门寺细脉浸染型钨矿产于燕山期似斑状黑云母花岗岩的内外接触带,与似斑状黑云母花岗岩的成岩时间一致,矿石硫同位素显示成矿物质来源于岩浆,反映似斑状黑云母花岗岩为细脉浸染型钨矿提供了钨金属,控制了矿体的成矿时间和产出空间。石门寺矿区似斑状黑云母花岗岩的源岩双桥山群含钨量高达9.16×10-6,部分熔融时钨金属趋于进入岩浆。富钨岩浆发生结晶分异,残留岩浆中钨金属得到进一步富集,该残留岩浆汇集到岩体顶部,出溶成矿流体。岩浆出溶的成矿流体使围岩晋宁期黑云母花岗闪长岩和燕山期的似斑状黑云母花岗岩发生云英岩化,导致岩石中铁、锰和钙等元素析出;这些铁、锰和钙与成矿流体中的钨金属结合,形成细脉浸染状黑钨矿和白钨矿。似斑状黑云母花岗岩的内、外接触带是矿体产出的空间,云英岩化的范围指示矿体产出的位置,岩体接触带和云英岩是找矿的直接标志。紧邻矿体的、产于似斑状黑云母花岗岩顶部的具有流体出溶性质的似伟晶岩壳岩性特征明显,野外极易辨认,可作为找矿的标志层。富钨的高分异S-型花岗岩小岩体及控岩构造是找矿的区域标志。Shimensi tungsten deposit was discovered in 2010 at Dahutang area,where the world＇s largest tungsten deposit was found. The veinlet-disseminated ores,accounting for about 74% of the total reserves,were hosted in the contact zones of Jinningian biotite granodiorite and Yanshanian porphyraceous biotite granite stock. And the tungsten ores are close with the porphyraceous biotite granite in age. The magmas of porphyraceous biotite granites were derived from the tungsten-rich Proterozoic Shuangqiaoshan group whose partial melting led to additional enrichment of tungsten metals in the melt. The tungsten-rich magma experienced strongly fractional crystallization and the tungsten metals in magma were substantially risen up and accumulated in the residual melts that were translated to ore-forming fluids late. The iron,magnesium,manganese,calcium and some other metal elements,which were taken out from the granitoids by ore-forming fluids,were combined with tungsten metals in ore-forming fluids to produce wolframites and scheelites. Therefore,porphyraceous biotite granites provided tungsten metals to veinlet-disseminated tungsten ores and restricted the ores in time and space. In Shimensi tungsten deposit,the contact zone and greisenization rocks are the indicators for veinlet-disseminated tungsten ores. And the pegmatite shells with Kfeldspar megacrysts,albite,and quartz perpendicular to the contact zone can be find very easily and be classed as marker bed. The tungsten-rich highly fractionated S-type porphyraceous biotite granite small stock and its rock-control structures are the regional prospecting criteria.

关 键 词：控矿作用 找矿意义 似斑状黑云母花岗岩 细脉浸染型钨矿 石门寺钨矿 赣西北 

分 类 号：P581[天文地球—岩石学]