新洲金矿床的地质特征及其成因

THE GEOLOGICAL CHARACTERISTICS AND FORMATION MECHANISM OF XINZHOU GOLD DEPOSIT IN NORTHERN GUANGDONG PROVINCE

广东新洲金矿床产于褶皱式推覆构造外来系统——震旦系乐昌峡群变质地层之中.金矿床主要属碎裂石英脉型,次为蚀变糜棱岩型.成矿作用早期形成糜棱岩型金矿,为韧性剪切成矿期;晚期形成碎裂石英脉型金矿、属韧-脆性和脆性成矿期.成矿溶液为浅成中低温变质-混合岩化热液,成矿物质来源于震旦系,属褶皱式逆冲推覆-剪切带型金矿床.

Xinzhou Au deposit and ore bodies occur as veins in the metamorphic Sinian Lechangxia Group in the allochthon of the fold-thrust nappe. The Au deposit is dominantly cataclastic quartz-vein type, secondly altered mylonite type. The early stage the mineralization is of ductile shearing, which formed the mylonite-type Au deposit. The later stage of mineralization is of ductile-brittle shearing and brittle shearing, which formed cataclastic quartz-vein type Au deposit. The ore solution is a metamorphosed and migmatized hydrothermal fluid formed in hypabyssal moderate-to low-temperature conditions and that the ore-forming materials come mainly from the metamorphic Sinian strata.Consequently, the Xinzhou gold deposit is considered to be a fold-thrust-shear zone type gold deposit.