| 甘肃寨上金矿床成矿特征与形成机理 |
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| 引用本文：马星华,李立兴,刘光智,廖延福,郑卫军.2010.Metallogenic characteristics and formation mechanism of Zhaishang gold deposit, southern Gansu Province[J].Mineral Deposits,29(1):85~100 |
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| 基金项目:国家重点基础研究发展规划(2006CB403500、2009CB421003)、国家自然科学基金(4 0773036)、高等学校学科创新引智计划(B07011) 、教育部长江学者和创新团队发展计划和 中国人民武装警察部队黄金指挥部勘查资助项目 |
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| 中文摘要:位于西秦岭礼(县)-岷(县)成矿带西段的寨上金矿床，是近年发现的一个大型微细浸染型金矿床。矿床赋存于中泥盆统和下二叠统，为一套由石英砂岩、粉砂岩、钙质板岩和灰岩组成的浊积岩建造。金矿体明显受断裂构造的控制。矿石中矿物组成相当丰富，既有大量硫化物、硫盐、氧化物、硫酸盐、碳酸盐、钨酸盐，又有碲化物、自然金属及多金属互化物。矿石中矿物种类较多、组成较复杂以及存在显微自然金，是寨上金矿床的特色。稀土元素配分型式以及硫、铅、碳、氧、氢等同位素组成等表明，成矿金属物质、硫和碳主要来自赋矿岩石和下伏地层，同时还有深部岩浆物质的参与。成矿溶液主要来自加热的循环地下水。矿化和蚀变作用是在水/岩比值较低的体系中进行的。成矿温度主要集中在120～240℃范围内。赋矿围岩中含Fe碳酸盐矿物溶解释放Fe以及溶解Fe的大量硫化物化，是寨上金矿床中存在显微可见自然金的最重要因素和金沉淀富集的有利条件。 |
| 中文关键词:地质学 金矿床 成矿特征 形成机理 寨上 甘肃 |
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| Metallogenic characteristics and formation mechanism of Zhaishang gold deposit, southern Gansu Province |
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| Abstract:Located in the western part of the Min-Li metallogenic belt within the West Qinling Mountains, the Zhaishang gold deposit is a large Carlin-type disseminated gold deposit discovered in recent years. The ore deposit occurs in the slightly metamorphosed Middle Devonian and Lower Permian clastic and carbonate strata composed of quartz sandstone, siltstone, calcareous slate and carbonate that comprise flyschoid formation. Gold mineralization is strictly controlled by a fault zone. Ore minerals are quite complex and consist of sulfides, sulfosalt, oxides, sulfate, carbonate, tungstate, telluride, native metals, and polymetallic intermetallic compounds. The diversity of mineral species in the ores and the existence of visible native gold minerals constitute outstanding features of the ore deposi t.In the light of the REE distribution patterns, it is reasonably considered that the ore-forming materials of the ore deposit had affinity mainly with host rocks. S, C, Pb, H and O isotopic compositions show that the ore-forming materials were derived mainly from country rocks and underlying rocks and partly from deeper sources. Data obtained suggest that the ore-forming fluids were derived predom inantly from an active meteoric groundwater system. The amount of the hydrothermal fluids in the ore-formaing and alteration system was relatively insignificant. Ore-forming temperatures are estimated to have been in the range of 120～240℃. The dissolution of ferruginous limestone in the host rocks and the sulfidation of the dissolved iron by H2S introduced by ore fluids constituted not only the most important depositional mechanism for the existence of visible gold grains but also the advantageous conditions for gold enrichment in the Zhaishang gold deposit. |
| keywords:geology, gold deposit, metallogenic characteristics, formation mechanism, Zhaishang, southern Gansu |
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