摘要
次生石英岩型非金属矿床明显受不同级别的火山构造控制,是中—酸性火山岩区一套很有特色的矿床组合;热源、水源、地层产状有机组合生成的环流热液是成矿的前提之一;成矿流体以重碳酸盐型、硫酸盐型为主,属中—低盐度热液;温度、pH值、fo_2等物理化学条件是矿床及矿种类刑的重要控制因素。本文在《次生石英岩容矿型非金属矿床系列的矿种、组合及其成矿作用特征》(1986)一文基础上,进一步总结这类矿床的成矿机理和地质地球化学模式。
Secondary quartzite type of non-metallic deposits is a distinctive suite of deposits in terranes of intermediate- acid volcanic rocks, which is apparently controlled by tectono-magmatic activity, basement structure, lithology, volcanic rock facies and occurence of ore- hosted strata. There are three types of structures favourable for mineralization: center of caldera, ring fracture zone of volcanic edifice border and periphery of resurgent volcanic dome. The paper still deals with geochemical conditions, and estimates some physico-chemial parameters for this type of deposits. It is shown that most ore-forming fluids of the deposits are medium- low salinity, acid- light acid and HCO3- type or SO42- type. Meteroic water is main component of the ore-forming fluids. T, pH, fo2 and others are important factors controlling deposits and ore species The deposits formed at temperature from 150 to 350 ℃ , belonging to epithermal deposits.
Based on the studies of geological, geochemical conditions, the source of ore-forming materials and the source of ore-forming fluids, the paper further sums up ore-forming mechanism and model for secondary quartzite type of non-metallic deposits.
关键词
非金属矿床
次生石英岩
控矿构造
Secondary quartzite type of non-metallic deposits, Factors controlling deposits, Ore-forming model.
