Nanoporosity in sulfide minerals, controls on mineral formation and mineral reactivity

Mineral replacement reactions are ubiquitous in Nature and are an important process by which elements redistribution occur in Earth’s crust. In the present doctoral work, the mineral replacement of chalcopyrite by copper sulfides (e.g., covellite, digenite) is experimentally investigated in presence of copper-rich fluids at mild hydrothermal conditions (180-300 oC). The replacement of chalcopyrite proceeds via a combination of interfaced coupled dissolution reaction and volume diffusion mechanisms. The confluence of both of these mechanisms leads to continuous exchange of isotope/trace elements; post replacement, via a newly identified mechanism, termed as ‘ICDR aided dynamic recrystallization’ or IADR.