Synchronous advanced argillic alteration and deformation in a shear zone-hosted magmatic hydrothermal Au-Ag deposit at the Temora (Gidginburg) Mine, New South Wales, Australia

Abstract

Paragenetic relations indicate that advanced argillic alteration at the Temora mine and the adjacent Dam- Lilydale prospect is coeval with movement along shear zones which host each system. The interaction between movement along the host structure and developing alteration zones of contrasting rheology controlled the flow of hydrothermal fluid and resultant overall system geometry. Neither of these systems represents older, typical epithermal or porphyry-related systems that were subsequently deformed. However, advanced argillic alteration at both prospects cuts across the peripheral parts of older porphyry-style alteration systems, with paragenetic relations analogous to the Butte and Dizon districts. Each system is characterized by an early phase of massive or breccia-textured, quartz-dominated advanced argillic alteration, cut by foliated mica-rich, quartz-absent advanced argillic alteration. Phase relations indicate that early quartz-saturated advanced argillic alteration developed at temperatures