Artículos de revistas
Thermal evolution of Andean iron oxide-apatite (IOA) deposits as revealed by magnetite thermometry
Fecha
2021Registro en:
Scientifc Reports (2021) 11:18424
10.1038/s41598-021-97883-3
Autor
Palma, Gisella
Reich Morales, Martín Herbert
Barra Pantoja, Luis Fernando
Ovalle, J. Tomás
Real, Irene del
Simon, Adam C.
Institución
Resumen
Magnetite is the main constituent of iron oxide–apatite (IOA) deposits, which are a globally important
source of Fe and other elements such as P and REE, critical for modern technologies. Geochemical
studies of magnetite from IOA deposits have provided key insights into the ore-forming processes
and source of mineralizing fuids. However, to date, only qualitative estimations have been obtained
for one of the key controlling physico-chemical parameters, i.e., the temperature of magnetite
formation. Here we reconstruct the thermal evolution of Andean IOA deposits by using magnetite
thermometry. Our study comprised a > 3000 point geochemical dataset of magnetite from several IOA
deposits within the Early Cretaceous Chilean Iron Belt, as well as from the Pliocene El Laco IOA deposit
in the Chilean Altiplano. Thermometry data reveal that the deposits formed under a wide range of
temperatures, from purely magmatic (~ 1000 to 800 °C), to late magmatic or magmatic-hydrothermal
(~ 800 to 600 °C), to purely hydrothermal (< 600 °C) conditions. Magnetite cooling trends are
consistent with genetic models invoking a combined igneous and magmatic-hydrothermal origin that
involve Fe-rich fuids sourced from intermediate silicate magmas. The data demonstrate the potential
of magnetite thermometry to better constrain the thermal evolution of IOA systems worldwide, and
help refne the geological models used to fnd new resources.