铧厂沟金矿床北部控矿剪切带地质特征及金的富集规律

Geological Characteristics and Regularity of Gold Enrichment of North Ore-Controlling Ductile Shear Zone in Huachanggou Gold Deposit

野外调研和室内分析结果表明,区域韧性剪切带在铧厂沟金矿床非常发育,并经历了右行—左行—右行多期(次)活动。北部控矿韧脆性剪切带是区域韧性剪切带演化的产物,以左行剪切为主,位于铁夹树—庙湾北部厚层灰岩的下部。北部金矿带受北部控矿剪切带控制,长度大于1 km,厚度约70cm,从地表延伸至1 120 m标高,未见尖灭趋势。黄铁矿是该类矿石中最重要的金属矿物。自然金是主要金矿物,有明金和显微金两种。矿石结构构造较为复杂,集中反映了热液矿床的构造特征。矿带的形成可划分为热液期和表生期。原生矿石中绝大部分明金、显微金中的包体金和裂隙金都与黄铁矿密切相关。黄铁矿(Ⅰ)经历了韧脆性变形,因而是金的最佳载体矿物。北部韧脆性剪切带的多期(次)活动,使金富集成为工业矿体。结合地质特征,预测该矿带可延伸至1 120 m以下一定深度。

The regional ductile shear zone is well developed in the Huachanggou gold deposit, and it has gone through multiple activities from right-handed earlier to left-handed later and then right-handed latest. The North ore-controlling ductilebrittle shear zone, which is the production of the evolution of the regional ductile zone, is located at the bottom of Tiejiashu-Miaowan thick-bedded limestone. The North gold ore zone, with a length of more than 1 km and a thickness about 70 cm, is controlled by North ore-controlling ductile shear zone, and nip-out tendency is not found from the surface to 1 120 m level. Pyrite is the most important metallic mineral in it. Natural gold, which includes phaneric gold and micro-gold, is the major gold mineral. And the micro-gold can be further divided into industion gold, interystal porositional gold and fissure gold. The complex ore structure and the sample structural style indicate the tectonic features of hydrothermal deposit. The formation of ore zone can be divided into hydrothermal stage and supergene stage. Most of the phaneritic gold in protogenous ore, and the inclusion gold and fracture gold in micro-gold ore are closely related to pyrite. It is clear that pyrite has experienced ductile-brittle deformation, and therefore it is the best carrier mineral of gold. Because of multiple activities of North ductile- brittle shear zone, the gold ore bodies are enriched. It is predicted that the ore zone may be discovered below the 1 120 m level.