Duration of hydrothermal alteration and mineralization of the Don Manuel porphyry copper system, central Chile

Gilmer, A. K., Sparks, R. S. J., Barfod, D. N. , Brugge, E. R. and Parkinson, I. J. (2021) Duration of hydrothermal alteration and mineralization of the Don Manuel porphyry copper system, central Chile. Minerals, 11(2), 174. (doi: 10.3390/min11020174)

Abstract

The Don Manuel porphyry copper system, located in the Miocene–Pliocene metallogenic belt of central Chile, contains spatially zoned alteration styles common to other porphyry copper deposits including extensive potassic alteration, propylitic alteration, localized sericite-chlorite alteration and argillic alteration but lacks pervasive hydrolytic alteration typical of some deposits. It is one of the youngest porphyry copper deposits in the Andes. Timing of mineralization and the hydrothermal system at Don Manuel are consistent with emplacement of the associated intrusions (ca. 4 and 3.6 Ma). Two molybdenite samples yielded consistent ages of 3.412 ± 0.037 and 3.425 ± 0.037 Ma. 40Ar/39Ar ages on hydrothermal biotites (3.57 ± 0.02, 3.51 ± 0.02, 3.41 ± 0.01, and 3.37 ± 0.01 Ma) are associated with potassic alteration. These ages are younger than the youngest intrusion by ~300 k.y. recording the cooling of the system below 350 °C. Such a time gap can be explained by fluxing of hot magmatic fluids from deeper magmatic sources.

• Item Type: Articles
• Keywords: Porphyry copper deposit, hydrothermal alteration, mineralization, thermal modeling, geochronology, Chile.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Barfod, Dr Dan
• Authors: Gilmer, A. K., Sparks, R. S. J., Barfod, D. N., Brugge, E. R., and Parkinson, I. J.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Minerals
• Publisher: MDPI
• ISSN: 2075-163X
• ISSN (Online): 2075-163X
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Minerals 11(2):174
• Publisher Policy: Reproduced under a Creative Commons licence