EARLY, DEEP MAGNETITE-FLUORAPATITE MINERALIZATION AT THE OLYMPIC DAM Cu-U-Au-Ag DEPOSIT, SOUTH AUSTRALIA

摘要: The Olympic Dam iron oxide copper-gold (IOCG)-uranium-silver deposit (South Australia) is hosted in the large breccia complex within ~1.59 Ga Roxby Downs Granite. This formed through multiple stages of hydrothermal activity and texturally destructive brecciation that affected granite. deepest diamond drill hole to date (RD2773, end at ~2,329 m) intersected weakly altered, situbrecciated granite (~370–2,329 a quartz-phyric felsic unit (~2,010–2,265 m). These two rock units host coarse-grained minerals, from ~2,150 m hole. main minerals this assemblage are magnetite (± hematite), pyrite, fluorapatite, quartz, with minor disseminated chalcopyrite, sericite, chlorite, rare earth element (REE)-fluorcarbonates, monazite, uraninite, thorite, galena, sphalerite, anhydrite, schorl, rutile, pyrrhotite. cut by abundant multiphase veinlets calcite fluorite ± barite) veins. A zircon U-Pb age for (1591 11 Ma) implies broadly coeval granite, whereas ages uraninite (1593.5 5.1 Ma), fluorapatite (1583.3 6.5 hematite (1592 15 indicate deposition U-REE–rich magnetite-fluorapatite-pyrite-quartz replacement occurred soon after emplacement granitic rocks. Sm-Nd dating ubiquitous veins suggests formation ~1.54 Ga. deep resembles those characteristic oxide-apatite deposits many other sensu stricto IOCG deposits. study confirms event involved significant widespread mineralization Cu-Au province.