武当—两郧地区主要赋矿地层及其成矿元素

CHARACTERISTICS OF MAIN ORE-HOST STRATA AND THEIR METALLOGENIC ELEMENTS IN WUDANG-YUNXI AND YUN-(XIAN) REGION

武当—两郧地区的金属矿床受一定地层层位控制。通过对中新元古代武当岩群、新元古代耀岭河组、上震旦统陡山沱组、下寒武统水沟口组和泥盆系等主要赋矿地层的赋矿特征及其成矿元素地球化学特点的分析 ,认为矿床的形成常常与该地层中成矿元素的原始浓集系数相对较高有关。武当岩群和耀岭河组中的成矿元素 (如 Au)浓集系数较低的原因可能是其成矿元素已发生迁移 ,并用于成矿或形成异常 ;陡山沱组、水沟口组和泥盆系具有为成矿提供物质来源的地球化学条件 ,特别是中泥盆统中产出的锑矿显然与较高的锑初始浓度有关。武当—两郧地区是环太平洋银成矿带西侧的银金比值低值区中的异常高值区 。

Metal deposits in Wudang-Yunxi and Yunxian region are controlled by special stratum position. The analysis of the ore-host characteristics and the geochemical characters of metallogenic elements in main ore-host strata (Mid-New Proterozoic Wudang Rock Group, New Proterozic Yaolinghe Formation, Upper Sinian Doushantuo Formation, Lower Cambrian Shuigoukou Formation and Devonian) indicates that the formation of deposits is often closely related to higher primitive concentrate parameters of metallogenic elements in the strata.The lower concentration of metallogenic elements,such as Au,in Wudang Rock Group and Yaolinghe Formation may be due to the displacement of metallogenic elements,which may form deposits or abnormaly.While Doushantuo and Shuigoukou Formations as well as Devonian possess geochemical conditions for the supply of the materials.The Sb deposit in the Middle Devonian,in particular,is obviously related to the high original Sb concentration.Wudang-Yunxi and Yunxian region,is an area of abnormal high w(Ag)/w(Au) ratio in the lower ratio region in the western circum-Pacific Ag metallogenic belt and this has the potential of large scale Au deposits.