Polymetallic veins and breccias and carbonate-replacement ore deposits in the Cyclades continental back arc, Greece, formed from a range of fluid and metal sources strongly influenced by the dynamics of the late Mesozoic-Cenozoic Hellenic subduction system. These complexities are recorded in the isotopic signatures of hydrothermal barite. We investigated 17 mineral occurrences on four Cycladic islands and from Lavrion on the mainland. Here, barite occurs in almost all deposit types of Miocene to Quaternary age. We used a multiple isotope and geochemical approach to characterize the barite in each deposit, including mineral separate analysis of δ³⁴S and δ¹⁸O and laser ablation-inductively coupled plasma-mass spectrometry of ⁸⁷Sr/⁸⁶Sr and δ³⁴S. Barite from carbonate-hosted vein and breccia Pb-Zn-Ag mineralization on Lavrion has a wide range of δ³⁴S (2–20‰) and δ¹⁸O (10–15‰) values, reflecting a mix of magmatic and surface-derived fluids that have exchanged with isotopically heavy oxygen in the carbonate host rock. Sulfur (δ³⁴S = 10–13‰) and oxygen (δ¹⁸O = 9–13‰) values of barite from the carbonate-hosted vein iron and barite mineralization on Serifos are permissive of a magmatic sulfate component. Barite from epithermal base and/or precious metal deposits on Milos has δ³⁴S (17–28‰) and δ¹⁸O (9–11‰) values that are similar to modern seawater. In contrast, barite from vein-type deposits on Antiparos and Mykonos has a wide range of δ³⁴S (16–37‰) and δ¹⁸O (4–12‰) values, indicating a seawater sulfate source modified by mixing or equilibration of the hydrothermal fluids with the host rocks. Strontium isotope ratios of barite vary regionally, with ⁸⁷Sr/⁸⁶Sr ≥ 0.711 in the central Cyclades and ⁸⁷Sr/⁸⁶Sr ≤ 0.711 in the west Cyclades, confirming the strong influence of upper crustal rocks on the sources of fluids, Sr, and Ba in the formation of ore.

中文翻译：

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基克拉泽斯大陆后弧多金属脉和碳酸盐岩矿床中热液重晶石的成因

希腊基克拉泽斯大陆弧后的多金属矿脉、角砾岩和碳酸盐交代矿床是由一系列流体和金属来源形成的，受到晚中生代-新生代希腊俯冲系统动力学的强烈影响。这些复杂性记录在热液重晶石的同位素特征中。我们调查了四个基克拉迪岛屿和大陆拉夫里翁的 17 个矿产地。在这里，重晶石几乎出现在中新世至第四纪的所有矿床类型中。我们使用多种同位素和地球化学方法来表征每个矿床中的重晶石，包括 δ ³⁴ S 和 δ ^{18 O 的矿物单独分析以及87} Sr/ ⁸⁶ Sr 和 δ ³⁴ S的激光烧蚀-电感耦合等离子体质谱分析。拉夫里昂碳酸盐岩矿脉和角砾岩 Pb-Zn-Ag 矿化物具有广泛的 δ ³⁴ S (2–20‰) 和 δ ¹⁸ O (10–15‰) 值，反映了岩浆和地表衍生的混合与碳酸盐母岩中的同位素重氧进行交换的流体。Serifos 上碳酸盐岩脉铁和重晶石矿化中重晶石的硫(δ ³⁴ S = 10–13‰) 和氧 (δ ^{18 O = 9–13‰) 值允许存在岩浆硫酸盐成分。}来自米洛斯岛浅成热液基底和/或贵金属矿床的重晶石具有与现代海水相似的δ ³⁴ S (17–28‰) 和 δ ^{18 O (9–11‰) 值。}相比之下，来自安提帕罗斯岛和米科诺斯岛脉型矿床的重晶石具有广泛的 δ ³⁴ S (16–37‰) 和 δ ¹⁸ O (4–12‰) 值，表明海水硫酸盐来源经过混合或平衡而改变。热液与主岩。重晶石的锶同位素比值因地区而异，基克拉泽斯中部地区⁸⁷ Sr/ ⁸⁶ Sr ≥ 0.711 ，基克拉泽斯西部地区⁸⁷ Sr/ ⁸⁶ Sr ≤ 0.711，证实了上地壳岩石对流体、锶和水的来源的强烈影响。巴中形成矿石。