| 贵州烂泥沟金矿成矿条件——岩石地球化学研究 |
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| 引用本文：.1995.Ore-forming conditions of the Lannigou gold deposit in southeastern Guizhou: A petrological and geochemical study[J].Mineral Deposits,14(1):51~58 |
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| 基金项目:中国科学院自然科学重点基金资助项目(KY85-12-01-30) |
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| 中文摘要:黔西南中三叠统浸染型的烂泥沟金矿具有储量大、原生矿发育的特征。岩石学（无机）和岩石地球化学的综合研究表明，金矿源为深部上古生界或更老地层的沉积；浊积岩容矿不仅具有物理障（主要是压力和孔渗性）方面的因素，而且包含化学障（如活性铁和有机碳）因素；成矿溶液具有还原、偏酸性特征。良好的深部矿源层，适宜的导矿和容矿构造，加上岩石适宜的物理-化学障等因素是烂泥沟金矿成为富矿、大矿的重要条件。 |
| 中文关键词:烂泥沟金矿 岩石地球化学 浊积岩 中三叠统 |
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| Ore-forming conditions of the Lannigou gold deposit in southeastern Guizhou: A petrological and geochemical study |
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| Abstract:The Lannigou gold deposit: is hosted in a turbidite sequence of Middle Triassic Bianyang Formation and has the largest reserves among disseminated gold deposits found in Southwest Guizhou. The gold orebody is strictly controlled by faults. Petrological and geochemical studies show that the differences of depositional fabrics between the orebody and the surrounding rocks are not obvious. Hydrothermal alterations in gold-hosting turbidites include silicificatiop, pyritization, and decarbonatization. From altered country rocks toward the center of the orebody, four alteration zones can be recognized: CD carbonate cementation zone; ③ carbonate-cement dissolution and well-developed sulfides zone; ③ Pyritization and silicification zone, and ④ silicalite ( jasperoid)zone. High grade gold ores generally occur in the 2nd and 3rd zones, and the silicalite zone is not always well-developed. Geochemical studies reveal that, compared with surrounding rocks, the gold ores are obviously enriched in Au-Hg-As-Sb element association, and have higher total REE content and LREE/HREE ratios but lower δEu. Carbonate cements of the gold ores have plenty of positive carbon isotope values. In addition, the intensity of gold mineralization is closely related to physical properties (permeability) of host rocks. Comprehensive studies indicate that the main source beds of gold are Late Paleozoic and/or older sediments originally related to basic volcanic events and anoxic depositional environments; host rocks, namely turbidites, served not only as a physical barrier ( i.e. its porosity and permeability), but also as a chemical barrier (i.e. its active iron and organtic carbon) for gold mineralization; ore-forming fluids had reducing and relatively acid characteristics. Suitable deep source beds, favorable structures for the migration of hydrothermal solution and precipitation of gold, and physical and chemical barriers of host rocks are all important factors for the formation of high grade and large scale Lannigou gold deposit. |
| keywords:the Lannigou gold deposit, Petrology and geochemistry, turbidite, Middle Triassic |
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