Metallogeny of the state of Oaxaca, southern Mexico: A review

Cano, Néstor; Camprubí, Antoni; Gonzáléz-Partida, Eduardo

doi:10.1016/j.jsames.2022.103992

Cited by 6 publications

(1 citation statement)

References 54 publications

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“…This investigation focuses on the El Hilo bonanza from the Natividad intermediate sulfidation epithermal deposit in southern Mexico (longitude: 96.428° W, latitude: 17.303° N). In this region, magmatic pulses from the latest Oligocene–Miocene account for dozens of magmatic-hydrothermal ore deposits, most of them epithermal in type 13 , 14 . We combined fluid inclusion studies, focused-ion beam (FIB) scanning electron microscopy (SEM), high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM), and high-resolution transmission electron microscopy (HRTEM) to examine El Hilo, where nanoparticulate acanthite (AgS 2 ), pearceite-polybasite ([Ag 9 CuS 4 ][(Ag,Cu) 6 (As,Sb) 2 S 7 ]), and electrum (AuAg) precipitated due to boiling of moderate-salinity hydrothermal fluids.…”

Section: Introductionmentioning

confidence: 99%

Nanomaterial accumulation in boiling brines enhances epithermal bonanzas

Cano,

González-Jiménez,

Camprubí

et al. 2023

Sci Rep

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Epithermal bonanza-type ores, characterized by weight-percent contents of e.g., gold and silver in a few mm to cm, are generated by mixtures of magmatic-derived hydrothermal brines and external fluids (e.g., meteoric) that transport a variety of metals to the site of deposition. However, the low solubilities of precious metals in hydrothermal fluids cannot justify the high concentrations necessary to produce such type of hyper-enriched metal ore. Here we show that boiling metal-bearing brines can produce, aggregate, and accumulate metal nanomaterials, ultimately leading to focused gold + silver ± copper over-enrichments. We found direct nano-scale evidence of nanoparticulate gold- and/or silver-bearing ores formed via nonclassical growth (i.e., nanomaterial attachment) during boiling in an intermediate-sulfidation epithermal bonanza. The documented processes may explain the generation of bonanzas in metal-rich brines from a range of mineral deposit types.

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Section: Introductionmentioning

confidence: 99%