【摘要】 铧厂沟金矿床赋存于新元古界碧口群细碧岩和泥盆系踏坡群灰岩中。矿体受高角度逆冲断层和韧-脆性剪切带控制,呈似层状、透镜状产出,是南秦岭典型的造山型金矿床。根据赋矿围岩不同,该矿床划分为细碧岩矿带和灰岩矿带。细碧岩矿带矿石中黄铁矿的δ³⁴S值范围为-1.3‰～4.7‰,呈塔式分布,具岩浆硫特征;灰岩矿带矿石中黄铁矿的δ³⁴S值为-14.8‰～1.9‰,离散度强,具有生物成因硫和地层硫的特征。矿石黄铁矿的δ³⁴S值均落入碧口群细碧岩（2.1‰～4.7‰）和踏坡群（-22.5‰～6.6‰）的δ³⁴S值范围,指示硫源主要为碧口群和踏坡群。Pb同位素组成中,细碧岩矿带矿石中黄铁矿²⁰⁶Pb/²⁰⁴Pb、²⁰⁷Pb/²⁰⁴Pb和²⁰⁸Pb/²⁰⁴Pb范围分别为18.017～17.856、15.530～15.585和38.150～38.413,灰岩矿带矿石中黄铁矿²⁰⁶Pb/²⁰⁴Pb、²⁰⁷Pb/²⁰⁴Pb和²⁰⁸Pb/²⁰⁴Pb范围分别为18.202～18.491、15.624～15.659和38.690～39.401。细碧岩矿带矿石黄铁矿与围岩细碧岩全岩的²⁰⁶Pb/²⁰⁴Pb、²⁰⁷Pb/²⁰⁴Pb和²⁰⁸Pb/²⁰⁴Pb值相近,灰岩矿带矿石黄铁矿Pb同位素投影点全部落入踏坡群灰岩地层范围内。以上S和Pb同位素结果表明,铧厂沟金矿床金属物质来源于新元古代碧口群细碧岩及泥盆系踏坡群。更多还原

【Abstract】 The Huachanggou gold deposit, found in the spilite of the Neoproterozoic Bikou Group and limestone of the Devonian Tapo Group, is a typical orogenic gold deposit in South Qinling. Bedded and lenticu lar ore bodies are restricted to high-angle reverse faults or ductile-brittle shear zones. Based on the differences of wall-rocks, two orebody types are present: spilite-hosted Au lodes and limestone-hosted Au lodes. The sulfur isotope studies indicate that the δ³⁴S values of the pyrite from the spilite-hosted Au lodes range from-1.3‰～4.7‰, distributed in a tower-like shape, which is suggestive of the mixing source of the sulfur. The δ³⁴S values of the pyrite from the limestone-hosted Au lodes range from-14.8‰～1.9‰, with a high discretization, suggesting that the sulfur was mainly sourced from bioclastic limestone strata. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios of the pyrite from the spilite-hosted Au lodes range within 18.017–17.856, 15.530–15.585, and 38.150–38.413, respectively, while those from limestone-hosted Au lodes range within 18.202–18.491, 15.624–15.659, and 38.690–39.401, respectively. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios of the spilite and pyrite from the spilite-hosted Au lodes are similar; both of them, together with the pyrite from the limestone-hosted Au lodes, lie on the same lines in the diagrams of ²⁰⁸Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁷Pb/²⁰⁴Pb vs. ²⁰⁶Pb/²⁰⁴Pb. For the mixing line, the two end members are spilite and an orogenic belt, respectively. All the evidence indicates that the metallogenic elements are sourced from the spilite of the Neoproterozoic Bikou Group and Devonian Tapo Group.更多还原