ABSTRACT Two overlapping legacy seismic profiles, 130 km long end to end, were shot in the 1990s over the Kuruman Hills on the western margin of the Kaapvaal Craton in southern Africa. The 6‐s profiles were aimed at investigating the crustal structure of the western Kaapvaal Craton as well as to locate potential continuation of the Witwatersrand gold‐bearing horizons beneath the cover rocks, the latter of which was unsuccessful. In this study, the legacy seismic data are reprocessed and used to image the iron‐oxide (mainly haematite) mineralization found in the Kuruman Formation of the Griqualand‐West Supergroup, which outcrops along the two seismic profiles. The seismic profiles are located close to the Sishen open pit iron mine, where one of the world's largest iron ore concentrations (986 Mt) is mined. The reprocessed and merged seismic data are combined with magnetic, magnetotelluric, borehole and outcrop data to constrain the interpretation, and all indicate the mineralization host rocks to have ∼500 m thickness and 950 m depth. The seismic data further reveal seismic reflections associated with multiple iron ore horizons, which are affected by a first‐order scale syncline and numerous near‐vertically dipping (∼65–80°) normal and reverse faults of various orientations and throws, thus providing insight into the structurally controlled iron ore mineralization in the area. Seismic tomography and magnetotellurics characterize the sediments to have a velocity ranging between 5000 and 6000 m/s and a resistivity of <10 Ωm. The seismic imaging of the syncline and associated structural disruptions is important for future mining purposes and plans in the area as these structures might have preserved iron‐oxide mineralization from erosion. The reprocessed data thus provide information that could be incorporated in potential future underground mine planning in the area, improving the resource evaluation of the iron‐oxide deposit. Legacy seismic data are thus shown to hold intrinsic quality and possible untapped potential that can be realized via data reprocessing.

中文翻译：

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来自遗留地震数据的新见解：对遗留 2D 地震数据进行再处理，以对南非 Sishen 矿附近的氧化铁矿化进行成像

摘要 在 1990 年代，在非洲南部 Kaapvaal 克拉通西缘的库鲁曼山上拍摄了两个重叠的遗留地震剖面，端到端长 130 公里。6 s 剖面的目的是研究 Kaapvaal Craton 西部的地壳结构，以及定位盖岩下 Witwatersrand 含金层位的潜在延续，后者未成功。在这项研究中，对遗留地震数据进行了重新处理，并用于对在 Griqualand-West 超群的库鲁曼组中发现的氧化铁（主要是赤铁矿）矿化进行成像，该矿化沿两个地震剖面出露。地震剖面位于四神露天铁矿附近，该矿是世界上最大的铁矿石集中地之一（986 吨）。再处理合并地震资料，结合磁、大地电磁、钻孔和露头资料进行解释约束，均表明成矿围岩厚度约500 m，深度约950 m。地震数据进一步揭示了与多个铁矿层相关的地震反射，这些地震反射受一级向斜和众多不同方向和断距的近垂直倾斜（~65-80°）正断层和反向断层的影响，从而提供了洞察力进入该地区结构可控的铁矿石矿化区。地震断层扫描和大地电磁学表征沉积物的速度在 5000 到 6000 m/s 之间，电阻率 <10 Ωm。向斜和相关结构破坏的地震成像对于该地区未来的采矿目的和计划很重要，因为这些结构可能保护了氧化铁矿化免受侵蚀。因此，重新处理的数据提供的信息可以纳入该地区未来潜在的地下矿山规划中，从而改善氧化铁矿床的资源评估。因此，传统地震数据显示出具有内在质量和可能未开发的潜力，这些潜力可以通过数据再处理来实现。