投稿时间：2023-07-18
修订日期：2024-01-09
网络发布日期：2024-03-08
中文摘要:金坑锡铜多金属矿位于广东莲花山断裂带北东段，是近些年来在粤东地区新发现的典型锡铜多金属矿，关于该矿床的成因类型和成矿机制一直存在较大争议。矿区勘查工作在马山矿段首次发现伴有明显铜矿化的热液隐爆角砾岩，对于揭示矿床成因具有重要意义。LA-ICP-MS锆石U-Pb年代分析结果显示，花岗质角砾成岩年龄约为150 Ma，εHf（t）值为-8.20~-4.55，二阶段Hf模式年龄值为1.73~1.49 Ga，指示岩浆主要来自于中元古代地壳物质，并有地幔物质加入。硫化物原位硫同位素分析结果显示，不同阶段硫化物硫同位素组成具有明显差别。第一阶段（Py-Ⅰ）和第二阶段（Py-Ⅱ）黄铁矿存在显著的硫同位素变化，前者为-0.65‰~1.11‰（n=5），后者为1.30‰~1.93‰（n=5），与Py-Ⅱ共生黄铜矿同位素值为1.42‰~1.87‰（n=16）。第三阶段硫化物中黄铜矿δ34S值为3.69‰~4.32‰（n=4），其中隐爆角砾岩胶结物中黄铜矿（Ccp-Ⅲa）δ34S为3.69‰~3.74‰，略低于第三阶段石英-绿泥石脉中黄铜矿（Ccp-Ⅲb）δ34S值（4.29‰~4.32‰）。第四阶段黄铁矿（Py-Ⅳ）δ34S值为-4.87‰（n=1），黄铜矿（Ccp-Ⅳ）δ34S值为-3.07‰（n=1）。基于成岩成矿年代及硫化物原位硫同位素分析，文章认为金坑锡铜多金属矿床可能存在两期岩浆热液活动的叠加，其中~150 Ma壳幔混合来源花岗质岩浆活动可能是触发矿区铜矿化的重要岩浆事件，早于后期锡矿的形成（~144 Ma），这一发现有望为莲花山断裂带锡铜多金属矿指引新的方向。
Abstract:The Jinkeng Sn-Cu polymetallic deposit is located in northeastern part of the Lianhuashan fault in Guangdong Province. It has long been hotly debated about its genesis. Hydrothermal cryptoexplosive breccia is first discovered in Mashan ore section of Jinkeng Sn-Cu polymetallic deposit by core logging and petrographic observation, and the hydrothermal activity can be divided into 5 stages in detail. On this basis, this paper carried out detailed zircon U-Pb dating of granitic breccia in hydrothermal cryptoexplosive breccia, and detailed in-situ sulfur isotope analysis of sulfide. The granite have zircon U-Pb age about 150 Ma, have εHf(t) values ranging from -8.20 to -4.55, and Hf model ages (TDM2) of 1.72~1.49 Ga, suggesting that the granite formed by the partial melting of Mesproterozoic crustal material, and contain a minor mantle-derived component. In-situ sulfur isotope analysis of sulfides show that there are obvious differencesed in sulfur isotopic composition of sulfides from different stages. Significantly, the sulfur isotope changes in pyrite of different stages before crushing (Py-Ⅰ:-0.65‰ to 1.11‰, n=5) and after deformation (Py-Ⅱ:1.30‰ to 1.93‰, n=5), and the δ34S of chalcopyrite associated with Py-Ⅱ is 1.42‰ to 1.87‰ (n=16). Chalcopyrite in the third stage have high δ34S values ranging from 3.69‰ to 4.32‰ (n=4), in which the δ34S value of chalcopyrite in cryptoexplosive breccia cement (Ccp-Ⅲa:3.69‰ to 3.74‰), which is slightly lower than that in quartz-chlorite vein (Ccp-Ⅲb:4.29‰ to 4.32‰). The pyrite from the fourth stage have lower δ34S value (Py-Ⅳ:-4.87‰, n=1; Ccp-Ⅳ:-3.07‰, n=1). Considering that the tin deposits in Jinkeng and its adjacent area are mainly formed in ~144 Ma, while the copper deposit is formed in 170~150 Ma. It is considered that there are at least two magmatic and hydrothermal events in Jinkeng deposit, in which the granitic magmatic activity derived from crust-mantle mixing of ~150 Ma may be an important magmatic event to trigger Cu mineralization in the mining area. This work could hopefully promote the Sn and Cu prospecting along Lianhuashan fault belt.
keywords:Lianhuashan fault hydrothermal superposition tin-copper polymetallic deposit eastern Guangdong
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基金项目:本文得到国家重点研发计划课题（编号：2022YFC2905101）、科技基础资源调查专项课题（编号：2022FY101701）、中国地质调查局项目（编号：DD2023350、DD20221692）联合资助
引用文本：
孙海瑞,吕志成,李永胜,韩志锐,于晓飞,杜轶伦.2024.粤东金坑锡铜多金属矿燕山期岩浆热液叠加成矿[J].矿床地质,43(1):177~194SUN HaiRui,LÜ ZhiCheng,LI YongSheng,HAN ZhiRui,YU XiaoFei,DU YiLun.2024.Yanshanian magmatic hydrothermal superimposed mineralization in Jinkeng Sn-Cu polymetallic deposit, eastern Guangdong Province[J].Mineral Deposits43(1):177~194
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