贵州威宁地区玄武岩铜矿地质特征

Geological Characteristic of Basaltic Copper Ores in the Weining Area of Guizhou

笔者以多元信息成矿预测为基础 ,对黔西北威宁地区的“玄武岩型 (层状 )铜矿”进行了理论预测和实地调查。新近获得的实际资料表明 ,此类铜矿主要赋存在P3em3 玄武岩多个喷发微旋回之中的“玄武质凝灰岩、沉凝灰岩、富含陆地 -沼泽相植物和有机质的正常沉积泥砂岩石”这一物质组成复杂、岩性岩相多变的“地质 -地球物理 -地球化学矛盾带”中。常见铜矿物有片状 ,粒状、块状自然铜、辉铜矿、蓝铜矿、少见孔雀石等 ,蚀变有沸石化、绿泥石化、沥青化、硅化等。综合分析认为该区玄武岩型层状铜矿化并非单一因素作用 ,而是多因素耦合放大———近源火山机构 (物源准备 )加上喷发间歇期有机质吸附 (初步富集 ) ,再加上深埋藏变质作用 (成矿热流体 )叠加的产物。

Basing on the metallogenic forecast of multiplex information, the theoretical prediction and field investigation on basalt-type bedded copper ores in the Weining area of northwestern Guizhou have been made The actual data obtained from recent works show that this kind of copper ores chiefly occurs at the contradictory zone in geology-geophysics-geochemistry with complex material composition and changeful lithology-lithofacies, involving in basaltic tuff, sedimentary tuff and organic normal deposited sandrock within several eruptive micro-circles of P 2em 3 basalt. The familiar copper minerals have native copper, azurite and chalcocite shaped in sheet, granular and block, and the malachite seldom appear, the alterations which include fluoritization, chloritization, bituminization and silicification. Integrated analyses suggest the mineralization on basalt-type bedded copper ores in this region are not resulted by single factor but rather the coupling amplification of the multi-factors with the additions of the proximal volcanic mechanism on material preparation, the organic absorption in eruptive intermittent stages on primary concentration, and the deep ground metamorphism on minerogenetic heat-flow superposition.