@misc{10481/81592,
year = {2023},
month = {3},
url = {https://hdl.handle.net/10481/81592},
abstract = {The Montecristo district, northern Chile, is one of the few places worldwide where there is a direct relationship between
magnetite-(apatite) (MtAp) mineralization and iron oxide-copper–gold (IOCG) mineralization. The MtAp mineralization
includes Ti-poor magnetite, fluorapatite, and actinolite and is crosscut and partially replaced by a younger IOCG mineralization
that includes a second generation of actinolite and magnetite with quartz, chalcopyrite, pyrite, and molybdenite.
The MtAp stage at Montecristo is interpreted as the crystallized iron-rich melts that used the pre-existing structures of the
Atacama Fault System as conduits. These rocks later acted as a trap for hydrothermal IOCG mineralization. Geochronology
data at Montecristo indicate that the host diorite (U–Pb zircon 153.3 ± 1.8 Ma, 2-sigma), MtAp mineralization (40Ar-39Ar in
actinolite, 154 ± 2 Ma and 153 ± 4 Ma, 2-sigma), and the IOCG event (Re-Os on molybdenite, 151.8 ± 0.6 Ma, 2-sigma) are
coeval within error and took place in a time span of less than 3.4 Ma. The εHfi and εNdi values of the host diorite are + 8.0
to + 9.8 and + 4.3 to + 5.4, respectively. The whole-rock 87Sr/86Sri values of the IOCG mineralization (0.70425 to 0.70442)
are in the lower end of those of the MtAp mineralization (0.70426–0.70629). In contrast, εNdi values for the IOCG mineralization
(+ 5.4 and + 5.7) fall between those of the MtAp rocks (+ 6.6 to + 7.2) and the host diorite, which suggests that
the IOCG event was related to fluids having a more crustal Nd (εNdi < + 5.7) composition than the MtAp mineralization.
This likely reflects the mixing of Nd from the MtAp protolith and a deep magmatic-hydrothermal source, very likely an
unexposed intrusion equivalent to the host diorite. Sulfur isotope compositions (δ34S, + 0.3 to + 3.4‰) are consistent with
a magmatic source.},
organization = {NSERC discovery grant to J.M. Hanchar (RGPIN/004649-2015)},
organization = {RTI2018-099157-A-I00 (MCI/AEI/FEDER, UE) research grant
to F. Tornos.},
publisher = {Springer Nature},
keywords = {MtAp deposits},
keywords = {IOCG deposits},
keywords = {Mineral chemistry},
keywords = {Isotope geochemistry},
keywords = {Geochronology},
keywords = {Coastal Cordillera Andes},
keywords = {Chile},
title = {The Montecristo mining district, northern Chile: the relationship between vein‑like magnetite‑(apatite) and iron oxide‑copper–gold deposits},
doi = {10.1007/s00126-023-01172-0},
author = {Mateo, Laura and Delgado Huertas, Antonio},
}