Formation of giant iron oxide-copper-gold deposits by superimposed, episodic hydrothermal pulses

• Published in: Communications Earth & Environment
• Main Authors: Real, Irene del, Reich Morales, Martín Herbert, Simon, Adam C., Deditius, Artur, Barra Pantoja, Luis Fernando, Rodríguez Mustafa, María A., Thompson, John F. H., Roberts, Malcolm P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springernature, England 2021
• Subjects: Carajas mineral province; O Stable-isotopes; Au-ag deposit; Apatite ioa; Iocg deposit; Northwest-territories; Structural controls; Sulfur isotopes; Prominent hill; Gawler craton; Candelaria; Northwest Territories
• Online Access: https://doi.org/10.1038/s43247-021-00265-w; https://repositorio.uchile.cl/handle/2250/186385

The Candelaria iron oxide-copper-gold deposit in Chile was formed by superimposed, episodic hydrothermal pulses with contrasting composition and temperature, according to micro-textural and compositional variations in actinolite, a common alteration mineral. Iron oxide-copper-gold deposits are a globally important source of copper, gold and critical commodities. However, they possess a range of characteristics related to a variety of tectono-magmatic settings that make development of a general genetic model challenging. Here we investigate micro-textural and compositional variations in actinolite, to constrain the thermal evolution of the Candelaria iron oxide-copper-gold deposit in Chile. We identify at least two mineralization stages comprising an early 675-800 degrees C iron oxide-apatite type mineralization overprinted by a later copper-rich fluid at around 550-700 degrees C. We propose that these distinct stages were caused by episodic pulses of injection of magmatic-hydrothermal fluids from crystallizing magmas at depth. We suggest that the mineralisation stages we identify were the result of temperature gradients attributable to changes in the magmatic source, rather than variations in formation depth, and that actinolite chemistry can be used as a proxy for formation temperature in iron oxide-copper-gold systems. ANID through Millennium Science Initiative Program NCN13_065 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 3200532 ANID through FONDECYT grant 1190105 National Science Foundation (NSF) 1924142 Versión publicada - versión final del editor