河南省西峡县梅子沟金多金属矿地质特征及成矿机制初探

A Preliminary Study on Geological Characteristics and Metallogenic Mechanism of Meizigou Gold Polymetallic Deposit in Xixia County of Henan Province

西峡县梅子沟金多金属矿床位于秦岭造山带、北秦岭构造亚带东段,属于伏牛山南坡金多金属成矿带。矿区出露地层主要为下古生界二郎坪群碎屑岩、火山碎屑岩及细碧-角斑岩系,NWW向展布的韧性剪切带发育,燕山期花岗岩大面积分布。该矿床属于构造破碎带蚀变岩型矿床,矿体严格受NWW向断裂构造控制。在总结梅子沟金多金属矿床成矿地质背景和矿床地质特征的基础上,根据矿区氢氧同位素等分析数据,认为早古生代形成了初始矿源层-二郎坪群;加里东期-海西期,因受构造变动、区域变质和岩浆活动的影响,使已有矿源层中的Au等成矿物质发生活化、迁移和再分配;燕山期大规模构造-岩浆活动对成矿起到了决定性的作用。矿床属于受构造控制的燕山晚期中低温热液金多金属矿。

Meizigou gold-polymetallic deposit in Xixia County is located in the eastern segment of North Qinling orogenic belt across the North Qinling tectonic subbelt,which belongs to the gold-polymetallic metallogenic belt on the southern slope of Funiu Mountain.The outcropping strata of the mining area are mainly clastic rocks,pyroclastic rocks and bibi porphyry series of the Erlangping Group in the Lower Paleozoic.NWW is developed in the ductile shear zone,and Yanshan granites are distributed in a large area.The deposit belongs to altered rock type deposit in structural fracture zone,and the ore body is strictly controlled by NWW trending fault structure.On the basis of summarizing the metallogenic geological background and geological characteristics of meizigou gold polymetallic deposit,we know that,according to the analysis data of hydrogen and oxygen isotopes,it is considered that erlangping group formed the initial ore-source layer was in early Paleozoic Caledonian-Hercynian,due to tectonic changes,regional metamorphism.Under the influence of magmatic activity,we have known that Au and other ore-forming materials in the existing source layer are activated,migrated and redistributed.The large-scale tectono-magmatic activity of Yanshanian played a decisive role in mineralization.The deposit belongs to the late Yanshanian middle-low temperature hydrothermal gold polymetallic deposit controlled by structure.