Geology of the Tropicana gold project, Western Australia / Геология золотого проекта "Тропикана", Западная Австралия

The Tropicana-Havana gold deposit is hosted by Archaean rocks that lie along the eastern margin of the Yilgarn Craton, Western Australia. The Mineral Resource for the project is 75.3 million tonnes grading 2.07 g/t for 5.01 Moz of gold. Gold mineralisation postdates peak granulite-facies metamorphism and formed from variably oxidised, higher temperature (>350˚C), silica-undersaturated fluids. Fluid flow in more competent domains was largely controlled by fracture and grain boundary permeability, and was accompanied by selective sulfide and secondary biotite replacement of metamorphic biotite and amphibole. Partitioning of strain into strongly biotite-sericite-pyrite-altered shear planes, dissolution fractures, and around lithons with jigsaw-fit breccia textures, is evident in domains with higher gold grades. Discrete, laterally continuous high-strain sericitebiotite-chlorite±graphite shear zones that bound ore zones are weakly anomalous in gold. Sulfides within the ore zones are dominated by fine pyrite (2-8%, <0.2mm) with minor chalcopyrite, electrum and telluride minerals. Free gold occurs as fine-grained (10-30 μm) inclusions in pyrite and along biotite-sericite fractures in silicate minerals. <...>