Abstract Acropolis is an Fe-oxide–copper–gold prospect ∼20 km from Olympic Dam, South Australia, and marked by near-coincident gravity and magnetic anomalies. Prospective Fe-oxide–apatite ± sulfide veins occur in Mesoproterozoic and Paleoproterozoic volcanic and granitoid host units beneath unmineralised sedimentary formations. We have produced a geological map and history of the prospect using data from 16 diamond drill holes, including LA-ICPMS and high-precision CA-TIMS ages. The oldest unit is megacrystic granite of the Donington Suite (ca 1850 Ma). A non-conformity spanning ca 250 My separates the Donington Suite and felsic lavas and ignimbrites of the Gawler Range Volcanics (GRV; 1594.03 ± 0.68 Ma). The GRV were intruded by granite of the Hiltaba Suite (1594.88 ± 0.50 Ma) and felsic dykes (1593.88 ± 0.56 Ma; same age as the Roxby Downs Granite at Olympic Dam). The felsic dykes are weakly altered and lack Fe-oxide–apatite–sulfide veins, suggesting that they post-date the main hydrothermal event. If correct, this relationship implies that the main hydrothermal event at Acropolis was ca 1594 Ma and pre-dated the main hydrothermal event at Olympic Dam. The GRV at Acropolis are the same age as the GRV at Olympic Dam and ca 3–7 My older than the GRV exposed in the Gawler Ranges. The gravity and magnetic anomalies coincide with sections through the GRV, Hiltaba Suite and Donington Suite that contain abundant, wide, Fe-oxide veins. The GRV, Hiltaba Suite and Donington Suite are unconformably overlain by the Mesoproterozoic Pandurra Formation or Neoproterozoic Stuart Shelf sedimentary formations. The Pandurra Formation shows marked lateral variations in thickness related to paleotopography on the underlying units and post-Pandurra Formation pre-Neoproterozoic faults. The Stuart Shelf sedimentary formations have uniform thicknesses. KEY POINTS Fe-oxide–apatite ± sulfide veins are hosted by the Gawler Range Volcanics (1594.03 ± 0.68 Ma), the Hiltaba Suite granite (1594.88 ± 0.50 Ma) and Donington Suite granite (ca 1850 Ma). The age of felsic dykes (1593.88 ± 0.56 Ma) interpreted to be post-mineralisation implies that the main hydrothermal event at Acropolis was ca 1594 Ma. The Gawler Range Volcanics at Acropolis are the same age as the Gawler Range Volcanics at Olympic Dam and ca 3 to 7 My older than the Gawler Range Volcanics exposed in the Gawler Ranges.

中文翻译：

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受高精度 CA-TIMS 年龄限制的南澳大利亚雅典卫城远景地质

摘要 Acropolis 是一个铁氧化物-铜-金矿区，距南澳大利亚奥林匹克大坝约 20 公里，以近乎重合的重力和磁异常为特征。潜在的氧化铁-磷灰石±硫化物脉出现在未矿化沉积地层下的中元古代和古元古代火山和花岗岩寄主单元中。我们使用来自 16 个金刚石钻孔的数据制作了地质图和远景历史，包括 LA-ICPMS 和高精度 CA-TIMS 年龄。最古老的单元是多宁顿套房的巨晶花岗岩（约 1850 Ma）。一个跨越约 250 My 的不整合面将多宁顿组和高勒山脉火山 (GRV; 1594.03 ± 0.68 Ma) 的长英质熔岩和熔结岩分开。GRV 被 Hiltaba Suite 花岗岩（1594.88 ± 0.50 Ma）和长英质岩脉（1593.88 ± 0.56 Ma；与奥林匹克大坝的 Roxby Downs Granite 相同年龄）。长英质岩脉蚀变较弱，缺乏铁氧化物-磷灰石-硫化物脉，表明它们晚于主要热液事件。如果正确，这种关系意味着雅典卫城的主要热液事件发生在大约 1594 Ma，并且早于奥林匹克大坝的主要热液事件。Acropolis 的 GRV 与 Olympic Dam 的 GRV 年龄相同，比 Gawler Ranges 中暴露的 GRV 大 3-7 My。重力和磁异常与通过 GRV、Hiltaba Suite 和 Donington Suite 的部分相吻合，这些部分包含丰富的、宽的氧化铁矿脉。GRV、Hiltaba Suite 和 Donington Suite 被中元古代 Pandurra 组或新元古代 Stuart Shelf 沉积地层不整合地覆盖。Pandurra 组显示出与下伏单元和后 Pandurra 组后新元古代断层上的古地形有关的厚度的显着横向变化。斯图尔特大陆架沉积地层具有均匀的厚度。要点 铁氧化物-磷灰石 ± 硫化物矿脉由 Gawler Range Volcanics (1594.03 ± 0.68 Ma)、Hiltaba Suite 花岗岩 (1594.88 ± 0.50 Ma) 和 Donington Suite 花岗岩 (ca 1850 Ma) 组成。长英质岩脉的年龄 (1593.88 ± 0.56 Ma) 被解释为后矿化意味着雅典卫城的主要热液事件是大约 1594 Ma。雅典卫城的高勒山脉火山与奥林匹克大坝的高勒山脉火山年龄相同，比高勒山脉中暴露的高勒山脉火山年龄大 3 到 7 岁。