The Formation of Iron Oxide – Copper – Gold and Iron Oxide- Apatite Deposits: New Constraints from Field Studies and Experiments

Talk by Adam C. Simon from the University of Michigan.

ABSTRACT
Iron oxide – copper – gold (IOCG) deposits and iron oxide – apatite (IOA) deposits are important sources of their namesake metals, as well as rare earth elements (REE), U, P, Ag, Co, Bi and Nb that are economically important byproducts in some deposits. Both deposit types occur globally and range in age from Late Archean to Plio-Pleistocene. Titanium-poor magnetite modally dominates IOA deposits and iron makes them economic. Magnetite and (specular) hematite modally dominate IOCG deposits but their contained copper makes them economic. There seems to be consensus that IOCG deposits formed by hydrothermal processes resulting in styles of mineralization that include structurally controlled veins and breccias, as well as disseminations and massive lenses. However, a common source of the hydrothermal ore fluid responsible for the formation of IOCG deposits remains unconstrained. In contrast, there is no consensus for the origin of IOA deposits, which exhibit varied styles of mineralization that include discordant breccias, dikes, veins, and massive tabular bodies, as well as disseminations in permeable volcano-sedimentary host rocks.

In this talk, I will present and discuss data that constrain the source of the mineralizing fluid(s) in IOCG and IOA systems, data that constrain the thermal evolution of IOCG and IOA systems, geochronologic data that constrain the relationship between IOCG and IOA mineralization within individual systems and speculate on what allows some subduction zone magmatic systems to evolve IOCG/IOA systems whereas others evolve porphyry mineral systems.

Woolnough Lecture Theatre UWA – From 4 pm to 4.45 pm

Date: 19 May 2022

Free event, no need to register