The origin of the carbonate-hosted Huize Zn-Pb-Ag deposit, Yunnan province, SW China: constraints from the trace element and sulfur isotopic compositions of pyrite
The origin of the carbonate-hosted Huize Zn-Pb-Ag deposit, Yunnan province, SW China: constraints from the trace element and sulfur isotopic compositions of pyrite
复制标题
云南省会泽碳酸盐锌铅银矿床的成因：黄铁矿微量元素和硫同位素组成的制约
DOI：
10.1007/s00710-019-00654-2
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发表时间：
2019
影响因子：
1.8
通讯作者：
Sasseville Christian
中科院分区：
文献类型：
--
作者：
Meng Yu-Miao;Hu Rui-Zhong;Huang Xiao-Wen;Gao Jian-Feng;Sasseville Christian
会泽锌铅银存款矿床是我国西南地区的一个重要铅锌矿床，其矿石储量超过500万吨。矿石品位Zn + Pb ≥ 25wt%，Ag 46-100 g/t。该存款是在石炭纪白云岩和石灰岩。硫化物矿化以闪锌矿、方铅矿和黄铁矿为主。根据黄铁矿的结构特征和矿物组合特征，可区分出4种类型的黄铁矿（Py 1-Py 4）与成矿作用的时空关系。黄铁矿1至3对应于黄铁矿-闪锌矿亚阶段，而Py 4对应于闪锌矿-方铅矿-黄铁矿亚阶段。黄铁矿1显示由一个富含包裹体的核心和一个不含包裹体的边缘组成的环带结构，而Py 2，Py 3和Py 4显示替换遗迹或过度生长的结构。Py 1的环带结构是由多期成矿流体形成的，Py 2-Py 4的交代遗迹结构是由晚期富铅锌流体交代黄铁矿形成的。黄铁矿中微量元素的变化是矿物包裹体、共沉淀矿物和不同流体成分共同作用的结果。闪锌矿、黄铁矿和方铅矿的δ 34 S值为10.4-23.5‰，表明硫可能来自于海相硫酸盐的热化学还原。会泽黄铁矿的Co和Ni含量（分别为0.02-9.5 ppm和0.08-143 ppm）和Co/Ni比值（~0.01-2.63）与沉积喷流矿床、海底热液喷口和沉积黄铁矿中的黄铁矿相似，这可能是由于低温（<~250 °C）、盆地卤水或海水中的黄铁矿沉淀所致。会泽黄铁矿的Co/Ni值低于密西西比河谷型锌铅矿床的Co/Ni值（~0.2-7.2）。会泽黄铁矿的钴和镍含量低于火山成因块状硫化物，氧化铁铜金，斑岩铜矿床，反对岩浆/火山成分的参与和二叠纪峨眉山玄武岩和铅锌矿化之间的直接成因联系。结合流体包裹体温度和银品位，将会泽存款定义为介于密西西比河谷型和高温碳酸盐交代型锌铅矿床之间的过渡类型。
The Huize Zn–Pb–Ag deposit in SW China has an ore reserve in excess of 5 Mt. with an ore grade of ≥25 wt% Zn + Pb and 46–100 g/t Ag. This deposit is hosted in Carboniferous dolostone and limestone. Sulfide mineralization is dominated by sphalerite, galena, and pyrite. Four types of pyrite (Py1 to Py4) are temporally and spatially related to mineralization distinguished on the basis of textural features and mineral associations. Pyrite 1 to 3 corresponds to the pyrite-sphalerite sub-stage, whereas Py4 corresponds to sphalerite-galena-pyrite sub-stage. Pyrite 1 shows zoned texture composed of an inclusion-rich core and an inclusion-free rim, whereas Py2, Py3, and Py4 show replacement relic or overgrowth textures. The zoned texture in Py1 was formed by multiple stages of ore fluids, whereas replacement relic texture in Py2 to Py4 was formed by replacement of pyrite by late Pb-Zn-rich fluids. Trace element variation in pyrite results from a combination of mineral inclusions, co-precipitating minerals, and various fluid compositions. Sphalerite, pyrite, and galena have δ34S values of 10.4–23.5‰, suggesting that sulfur was probably derived from the thermochemical reduction of marine sulfates. The Huize pyrite has Co and Ni concentrations (0.02–9.5 ppm and 0.08–143 ppm, respectively) and Co/Ni ratios (~0.01–2.63) similar to pyrite from sedimentary exhalative deposits, submarine hydrothermal vents, and sedimentary pyrite, which may be due to pyrite precipitation from low-temperature (<~250 °C), basin brines or seawater. The Co/Ni ratios of the Huize pyrite are lower than those (~0.2–7.2) of pyrite from Mississippi Valley-type Zn-Pb deposits. The Huize pyrite has Co and Ni contents lower than those associated with volcanogenic massive sulfide, iron oxide copper gold, and porphyry Cu deposits, arguing against the involvement of a magmatic/volcanic component and a direct genetic link between Permian Emeishan basalts and Pb-Zn mineralization. Combining with fluid inclusion temperatures and silver grade, we define the Huize deposit as a transitional type between Mississippi Valley-type and high-temperature carbonate-replacement Zn-Pb deposits.