The Rajapalot area of Finnish Lapland hosts an unusually high-grade association of cobalt-only and gold–cobalt deposits (10.91 Mt @ 2.5 g/t Au + 0.44% Co total inferred resources) within multiply folded metasedimentary rocks of the Paleoproterozoic Svecofennian collisional orogeny. Through the integration of X-ray computed micro-tomography and micro-X-ray fluorescence raster imaging of drill-core samples, we produce a model of cobalt-bearing ore mineralisation, which reveals primary fluid transportation mechanisms and precipitation pathways. When combined with the deposit-scale, high-resolution ground-based magnetic geophysical data, we show that cobalt-bearing ores in the Rajapalot region occur mostly as saddle reefs located in dilated fold hinges, which formed by simultaneous synthetic and antithetic shearing along developing crenulation-cleavage planes and incompetent bedding layers, respectively. We suggest that multi-layered rock complexes with alternations of competent and incompetent layers deformed and metamorphosed to upper greenschist-lower amphibolite facies should represent focus regions for cobalt exploration targeting campaigns in orogenic belts. The non-destructive workflow presented in this study could be an integral part of an early stage of cobalt mineral processing and traceability before metallurgical treatment.

芬兰拉普兰的 Rajapalot 地区在古元古代 Svecofennian 碰撞造山运动的多重褶皱变沉积岩中拥有异常高品位的纯钴矿床和金钴矿床组合（10.91 Mt @ 2.5 g/t Au + 0.44% Co 总推断资源量） 。通过整合 X 射线计算机显微断层扫描和钻芯样本的显微 X 射线荧光光栅成像，我们建立了含钴矿石矿化模型，揭示了主要的流体输送机制和沉淀途径。结合矿床规模、高分辨率地基磁性地球物理数据，我们发现拉贾帕洛特地区的含钴矿石主要以位于膨胀褶皱铰链中的鞍状礁体形式出现，这些鞍状礁体是在发育过程中同时合成和对立剪切而形成的。分别是圆齿状解理面和无能的床上层。我们认为，具有变形和变质作用的上绿片岩-下角闪岩相的有效层和无效层交替的多层岩石杂岩应代表造山带钴勘探活动的重点区域。本研究中提出的无损工作流程可以成为钴矿物加工早期阶段和冶金处理前可追溯性的一个组成部分。