Dongping is the largest Au-Te vein deposit (~120 t Au) in the North China craton, but its age, origin, and setting remain unsolved. Here, we integrate paragenesis, geochemistry, and in situ U-Pb geochronology of garnet to constrain the timing and possible origin of the Dongping Au-Te deposit. Gold mineralization at Dongping is hosted in the Shuiquangou alkaline complex (ca. 401–390 Ma) and dominated by quartz-sulfide veins with minor ores in adjacent alteration envelopes. Andradite to grossular garnets are recognized in pre-, syn-, and post-ore quartz veins as well as mineralized alteration envelopes and are closely associated with a variety of ore and gangue minerals, mainly including K-feldspar, quartz, specularite, magnetite, pyrite, tellurides, epidote, and calcite. The paragenetic, textural, fluid inclusion, and compositional data suggest that garnets precipitated directly from a low-salinity fluid at 302° to 383°C and 90 to 330 bar.Garnets from various veins and alteration envelopes have similar U contents ranging from 0.80 to 13.89 mg/kg and yield reproducible U-Pb dates of 142 ± 5 to 139 ± 6 Ma (1σ) by laser ablation-inductively coupled plasmamass spectrometry. The dating results suggest that gold mineralization at Dongping occurred in the Early Cretaceous and thus preclude a genetic link between Au-Te mineralization and the ore-hosting alkaline intrusion as commonly suggested. When combined with independent geologic, geochemical, and geochronological studies, the new garnet U-Pb dates allow us to classify the Dongping Au-Te deposit as an oxidized intrusion-related gold deposit, with the causative magma likely derived from melting of an ancient enriched lithospheric mantle source due to destruction of the subcontinental lithospheric keel beneath the North China craton—a catastrophic event induced by the westward subduction of the Paleo-Pacific plate. This study highlights garnet U-Pb dating as a potential robust geochronometer for gold vein deposits elsewhere.

中文翻译：

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华北克拉通东坪金铁矿床的年龄和成因再探：石榴石共生，地球化学和原位U-Pb年代学的证据

东平是华北克拉通最大的Au-Te脉矿床（〜120 t Au），但其年龄，成因和环境仍未解决。在这里，我们整合了石榴石的共生，地球化学和原位U-Pb地球年代学，以约束东平金铁矿床的时间和可能的成因。东坪的金矿床位于水泉沟碱性复合体（约401-390 Ma）中，并以石英硫化物脉为主，邻近的蚀变信封中有少量矿石。从矿石中，矿石中和矿石后的石英脉以及矿化蚀变包膜中都可以识别出辐射状到石榴石状的石榴石，并且与各种矿石和mineral石矿物紧密相关，主要包括钾长石，石英，镜面石，磁铁矿，黄铁矿，碲化物，埃迪奥迪德和方解石。共生的，质地的，流体的包裹体，组成数据表明，石榴石直接从302°至383°C和90至330 bar的低盐度流体中析出。来自不同脉络线和蚀变包膜的石榴石具有相似的U含量，范围从0.80至13.89 mg / kg，可生产可重现的U激光烧蚀-电感耦合等离子体质谱法测定的-Pb数据为142±5至139±6 Ma（1σ）。测年结果表明，东坪的金矿化发生在白垩纪早期，因此排除了通常所建议的Au-Te矿化和含矿性碱性侵入岩之间的遗传联系。与独立的地质，地球化学和地质年代研究相结合，新的石榴石U-Pb年代使我们可以将东平金铁矿床归类为氧化入侵相关的金矿床，引起的岩浆可能是由于华北克拉通下方的次大陆岩石圈龙骨的破坏而融化了古代丰富的岩石圈地幔源所引起的，这是由古太平洋板块向西俯冲引起的灾难性事件。这项研究强调了石榴石U-Pb测年法可作为其他地方金矿床潜在的稳健天文钟。