# Thermal evolution and formation of supergene mineralization in the El Salvador District, Chile: evidence from geo-thermochronology.

Paula Montiel, Stephanie Brichau, Marcelo Farias, Cristopher López, Rodrigo Riquelme, Caroline Sanchez, Marc Poujol, et al.

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## To cite this version:

Paula Montiel, Stephanie Brichau, Marcelo Farias, Cristopher López, Rodrigo Riquelme, et al. Thermal evolution and formation of supergene mineralization in the El Salvador District, Chile: evidence from geo-thermochronology. 29 ème édition de la réunion des sciences de la Terre (RST 2025), Société Géologique de France (SGF), Oct 2025, Montpellier, France. pp.658557. insu-05350797

HAL Id: insu-05350797

https://insu.hal.science/insu-05350797v1

Submitted on 6 Nov 2025

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Distributed under a Creative Commons Attribution 4.0 International License
Thermal evolution and formation of supergene
mineralization in the El Salvador District, Chile:
evidence from geo-thermochronology.

Paula Montiel*<fnref n="1" />,<fnref n="2" />, Stéphanie Brichau<fnref n="3" />,<fnref n="4" />, Marcelo Farías<fnref n="5" />, Cristopher López<fnref n="6" />, Rodrigo Riquelme<fnref n="6" />, Caroline Sanchez<fnref n="6" />,<fnref n="7" />, Marc Poujol<fnref n="8" />, Stéphanie Duchêne<fnref n="9" />, Eduardo Campos<fnref n="10" />, Sandrine Choy<fnref n="11" />, Jorge Morales-Leal<fnref n="12" />, and Mathieu Leisen<fnref n="11" />

Résumé

Chile is one of the world's leading copper producers. The deposits are mainly derived from the alteration of copper porphyries located in varied morphotectonic and climatic contexts. Indeed, above subduction systems, these porphyries feature hypogene mineralization formed by hydrothermal fluids related to the emplacement of these intrusives, subsequently altered in supergene mineralization by surface water interaction. Previous studies (i.e., Clark et al., 1990) have demonstrated that the equilibrium between tectonic, climatic, and erosional processes allows supergene cooper mineralization (SCM) formation and preservation. This study aims to characterize the morphotectonic and climatic conditions associated with the development of supergene mineralization in the El Salvador-Potrerillos Mining District,

<footnote n="1">¹Universidad de Chile – Chili</footnote>

<footnote n="2">²Université Toulouse III Paul Sabatier – Université Toulouse III - Paul Sabatier - France</footnote>

<footnote n="3">³Institut de Recherche pour le Développement (IRD) – Institut de Recherche pour le Développement –
Adresse du siège - Le Sextant 44, bd de Dunkerque, CS 90009 13572 Marseille cedex 02, France</footnote>

<footnote n="4">⁴Universidad de Chile - Chili</footnote>

<footnote n="5">⁵Department of Geology, FCFM, University of Chile - Chili</footnote>

<footnote n="6">⁶Universidad Catolica del Norte - Chili</footnote>

<footnote n="7">⁷Géosciences Environnement Toulouse (GET) – Observatoire Midi-Pyrénées, Institut de recherche pour le développement [IRD] : UR234, Université Paul Sabatier (UPS) - Toulouse III, CNRS : UMR5563, Université Paul Sabatier [UPS] - Toulouse III, Institut de recherche pour le développement [IRD] : UMR239 – Observatoire Midi-Pyrénées 14 Avenue Edouard Belin 31400 Toulouse, France</footnote>

<footnote n="8">⁸Géosciences Rennes – Univ Rennes - CNRS, UMR 6118 – France</footnote>

<footnote n="9">⁹Géosciences Environnement Toulouse (GET) – Observatoire Midi-Pyrénées, Institut de recherche pour le développement [IRD] : UMR239, Université Paul Sabatier [UPS] - Toulouse III, CNRS : UMR5563, Université Paul Sabatier (UPS) - Toulouse III – France</footnote>

<footnote n="10">¹⁰Universidad Católica del Norte – Av. Angamos 0610, Antofagasta, Chili</footnote>

<footnote n="11">¹¹Géosciences Environnement Toulouse – Observatoire Midi-Pyrénées, Institut de recherche pour le développement [IRD] : UMR239, Université Paul Sabatier [UPS] - Toulouse III, CNRS : UMR5563, Université Paul Sabatier (UPS) - Toulouse III – France</footnote>

<footnote n="12">¹²Universidad Santo Tomas – Chili</footnote>

<footnote>*Intervenant</footnote>
located at the margin between the Central Depression and the Andean range, using low-
temperature thermochronology and geochronology.

We present new ages obtained in Permian to Oligocene intrusives in the El Salvador and Potrerillos districts, using AFT, AHe, and U-Pb zircon dating methods. Preliminary results indicate U-Pb ages ranging between 290.7±1.7Ma and 32.99±0.32Ma, and AHe ages ranging from 64.41±9.0Ma to 13.80±6.1Ma. These results show that the magmatic activity occurred from the late stages of the Gondwanic cycle to the Andean cycle while its exhumation history lasted until the Miocene in this region.

In El Salvador, previous studies have demonstrated that supergene processes was active between late Oligocene to early Miocene. Some authors attribute the cessation of supergene formation to aridification during the middle Miocene(Mote et al.,2001) also enabling its preservation.

We expect to report new U-Pb ages obtained on unconventional supergene copper min-
erals (silicates, carbonates, and phosphates), completed with previously published data for
the local supergene profile (e.g., Mote et al.,2001; Bissig and Riquelme,2010; Morales-Leal
et al.,2022).

These results will allow us to constrain the chronology of supergene formation to compare it
with 1)the exhumation history of the porphyries; 2)the case study of the Centinela District
(Sánchez et al.,2018) located further north in the Atacama Region.

With this study, we look forward to assess the factors controlling the development and
preservation of supergene copper mineralization from districts experiencing similar tectonic
conditions but with very different water inputs, even though both are located in an arid
climatic region.

Mots-Clés: Minéralisation supergene, datation, tectonique, relief, climat, Chili