摘要
本文取材于《广西大瑶山西侧泥盆系铅锌黄铁矿控矿条件及成矿预测研究》成果。根据含矿岩系普遍含有机质,富铅锌矿石结构中含有沥青,说明有机质的演化或干酪根的热解效应与多金属成矿作用密切相关。在研究有机质的丰度、类型和演化的基础上,结合镜质体反射率的分布规律,提出多金属矿化阶段:即成岩铅锌矿床和石油演变阶段的湿气-干气保存阶段相当,R_0值为2-2.7,成矿温度为185°-200℃;成岩-后生铅锌矿床为干气保存阶段,R_0值为2.7-3.5,成矿温度为200°-230℃;后生重晶石矿床为干气裂解阶段,成矿温度 > 230℃。
This paper is based on the research preject'' The Controls and Minerogenilic Prognosis of Devonian Pb-Zn-bearing Pyrite Deposits in Western Dayaoshan Mountain, Guangxi ' The organic matter is very common in the ore-bearing formation and the bitumen has been found in the high-grade Pb-Zn ores. All these facts show that there may exist a close relation between the evolution of the organic matter or the effect of thermal decomposition of kerogen and polymetallic mineralization. On the basis of studies of the abundance, type, and evolution of the organic matter as well as the distribution of the relectance of vitrinite, the polymetallic stages of mineralization are proposed. These stages are as follows.
(1) diagenetic lead-zinc mineralization stage which corresponds to wet-dry gases preserved stage in the evolution of oil, with Ro value varying from 2 to 2.7 and ore-forming temperature 185° -200℃ ; (2) diagenetic-epigenetic lead-zone mineralization stage which corresponds to dry gas preserved stage with Revalue varying from 2.7 to 3.5 and ore-forming temperature 200 ° -230℃ ; (3) epigenetic barite mineralization stage which corresponds to cracking stage of dry gas, with ore-forming temperature over 230℃.
