Deformation and mineralisation in the Scotty Creek Basin, Agnew district, Eastern Goldfields, Western Australia: evidence for D1- and D3-related gold mineralisation

AbstractGold deposits in the Agnew district display markedly different structural styles. The Waroonga and Songvang deposits are hosted in layer-parallel extensional shears formed under highly ductile conditions. In contrast, the New Holland–Genesis deposits are shallow-dipping quartz-filled brittle fractures and breccia zones that cut across the tightly folded bedding and formed during east–west compression. It is difficult to attribute their formation to a single compressive event. The Waroonga and Songvang deposits formed during D1 extension, uplift and exhumation of the Agnew granitic complex and formation of the Scotty Creek Basin at ca 2670–2660 Ma. The New Holland–Genesis deposits formed during east–west D3 compression at about ca 2650–2630 Ma. An S1 foliation wraps around the Agnew granitic complex and L1 stretching lineations form a radial pattern around the granite, consistent with formation during D1 uplift of the composite granite body. Uplift and erosion of granite bodies in the surrounding a...