The Bohemian Massif hosts significant hydrothermal U-deposits associated with shear zones in the high-grade metamorphic basement. But there is a lack of evidence of a genetic link between mineralization and U-fertile igneous rocks. This contribution provides constraints on the major U source of the vein-type U-deposits, the timing of ore formation and the metallogenetic model. The anomalous trace element signatures of the low-temperature hydrothermal deposits (high Zr, Y, Nb, Ti, ∑REE) and their close spatial relation with ultrapotassic rocks of the durbachite series point to a HFSE and REE enriched source rock. The durbachites have high U content (13.4–21.5 ppm) mainly stored in magmatic uraninite and other refractory minerals (e.g., thorite, zircon, allanite) that became metamict over a time interval sufficient to release U from their crystal structure, as suggested by the time gap between emplacement of the durbachites (EMP uraninite U–Pb age ~ 338 Ma) and hydrothermal activity (SIMS uranium ore U–Pb age ~ 270 Ma). Airborne radiometric data show highly variable Th/U ratios (1.5–6.0), likely reflecting a combination between (1) crystallization of magmatic uraninite, (2) hydrothermal alteration, and (3) leaching and mobilization of U along NW–SE-trending fault zones, manifested by elevated Th/U values in the radiometric map. The presence of rare magmatic uraninite in durbachites suggests almost complete uraninite dissolution; EMP imaging coupled with LA-ICP-MS analyses of refractory accessory phases revealed extensive mobilization of U together with HFSE and REE, providing direct evidence for metal leaching via fluid-driven alteration of radiation-damaged U-rich minerals. The large-scale HFSE and REE mobilization, demonstrated by the unusual trace element signatures of the U-deposits, was likely caused by low-temperature (270–300 °C), highly alkaline aqueous solutions containing F-, P-, and K-dominated complexing ligands. The first SIMS U–Pb age of 270.8 ± 7.5 Ma obtained so far for U-mineralization from the Bohemian Massif revealed a main Permian U mineralizing event, related to crustal extension, exhumation of the crystalline basement, and basin formation, as recorded by U–Pb apatite dates (280–290 Ma) and AFT thermal history models of the durbachites. The Permo-Carboniferous sedimentary cover probably represented a source of oxidized basinal brines infiltrating the basement-hosted durbachite plutons and triggering massive metal leaching. The interaction between basin-derived brines and durbachites resulted in significant modification of the chemical composition of the hydrothermal system (K and F release during biotite chloritization, P liberation through monazite alteration), leading to the formation of ore-bearing fluids responsible for the metallogenesis of the basement-hosted unconformity-related U-deposits in shear zones in the Bohemian Massif.

波希米亚地块蕴藏着大量与高品位变质基底剪切带相关的热液铀矿床。但缺乏证据表明矿化作用与富含铀的火成岩之间存在遗传联系。这一贡献对脉型铀矿床的主要铀来源、成矿时间和成矿模型提供了限制。低温热液矿床的异常微量元素特征（高 Zr、Y、Nb、Ti、ΣREE）及其与杜巴奇特系列超钾岩的密切空间关系表明，烃源岩富含 HFSE 和 REE。杜巴奇石具有高 U 含量 (13.4–21.5 ppm)，主要储存在岩浆铀矿和其他难熔矿物（例如钍铁矿、锆石、铜铝榴石）中，这些矿物在一段足以从其晶体结构中释放 U 的时间间隔内变成变晶，如durbachite 侵位（EMP 铀矿 U-Pb 年龄 ~ 338 Ma）和热液活动（SIMS 铀矿 U-Pb 年龄 ~ 270 Ma）之间的时间差。机载辐射测量数据显示 Th/U 比率变化很大 (1.5–6.0)，可能反映了 (1) 岩浆铀矿结晶、(2) 热液蚀变和 (3) 沿 NW-SE 走向的 U 淋滤和迁移之间的组合断层带，表现为辐射图中 Th/U 值升高。杜巴赫岩中存在稀有岩浆铀矿，表明铀矿几乎完全溶解； EMP 成像与难熔辅助相的 LA-ICP-MS 分析相结合，揭示了 U 与 HFSE 和 REE 一起广泛流动，为通过辐射损坏的富 U 矿物的流体驱动蚀变进行金属浸出提供了直接证据。铀矿床异常的微量元素特征表明，大规模的 HFSE 和 REE 动员很可能是由含有 F-、P- 和 K 的低温（270-300 °C）、高碱性水溶液引起的- 主导的络合配体。迄今为止，从波希米亚地块获得的第一个 SIMS U-Pb 年龄为 270.8 ± 7.5 Ma，揭示了二叠纪主要的 U 矿化事件，与地壳伸展、结晶基底折返和盆地形成有关，如 U 记录的–Pb 磷灰石年代 (280–290 Ma) 和杜巴赫石的 AFT 热史模型。二叠纪-石炭纪沉积盖层可能是氧化盆地卤水的来源，这些卤水渗透到基底的杜巴赫岩体中并引发大量金属浸出。盆地卤水和杜巴奇石之间的相互作用导致热液系统的化学成分发生显着改变（黑云母绿泥石化过程中释放钾和氟，通过独居石蚀变释放磷），从而形成负责成矿作用的含矿流体波希米亚地块剪切带中基底与不整合面相关的 U 矿床的研究。