摘要
西秦岭泥盆系层控铅锌矿带内所有矿床,都经历了同生热液沉积成矿期和变质热液弱改造成矿期或动力分异热液强改造成矿期,并均受到中低温同生成矿作用和中高温热液改造成矿作用影响。不同矿化带的成矿物理化学环境有异,但矿液皆系氯化物(Na^+-K^+-Cl^-)型的热卤水,且其中的成矿元素主要以氯络合形式存在,含量都高达n×10^(-5)～n×10^(-4)。随成矿作用的演化,成矿流体的压力、硫逸度、CH^4和SO_4^(2-)含量有所增高,而氧逸度、H_2S和HS^-5含量则有所降低,成矿流体的酸性程度和还原能力分别有所减弱和增强。
All ore deposits in the Devonian stratabound Pb-Zn metallogenie belt ofthe west Qinling have two metallizing phases: the syngenetie hydrothermaldepositional metallizing phase and the metamorphic hydrothermal weaklyreworked metallizing phase or the dynamo-differential hydrothermal stronglyreworked metallizing phase under the influence of the low to intermediatetemperature syngenetie mineralization and the intermediate to high temperaturehydrothermal reworked mineralization. There are certain differences in themetallogenetic physicochemical conditions between the different two mineralizedzones, but their ore-forming solutions are the chloride type (Na^+ -Cl^- -K^+)hot brine. And the ore-forming elements Pb, Zn of the ore fluid mainlyexist in the occurrence of Pb and Zn chloride complexes, and their contentsin the fluid are as high as about n×10^(-5)～n×10^(-4). From the syngeneticmetallizing phase to the reworked metallizing phase the metallogenic pressure,sulfur fugacity, contents of CH_4 and SO_4^(2-) of the ore fluid are on the increase,whereas oxygen fugacity, contents of H_2S and HS^- are on the decrease. Theacidity and reducibility of the ore fluid, in some degree, are on the decreaseand increase respectively with the evolution of metallization.
关键词
铅锌矿
成矿
物理化学
层控
泥盆纪
Pb-Zn deposit
Devonian system
stratabound deposit
metallization
physicochemical condition
west Qinling
