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How metalliferous brines line Mexican epithermal veins with silver
journal contribution
posted on 2023-05-17, 21:28 authored by Jamie Wilkinson, Simmons, SF, Stoffell, BWe determined the composition of ,30-m.y.-old solutions extracted from fluid inclusions in one of the world’s largest and richest silver ore deposits at Fresnillo, Mexico. Silver concentrations average 14 ppm and have a maximum of 27 ppm. The highest silver, lead and zinc concentrations correlate with salinity, consistent with transport by chloro-complexes and confirming the importance of brines in ore formation. The temporal distribution of these fluids within the veins suggests mineralization occurred episodically when they were injected into a fracture system dominated by low salinity, metal-poor fluids. Mass balance shows that a modest volume of brine, most likely of magmatic origin, is sufficient to supply the metal found in large Mexican silver deposits. The results suggest that ancient epithermal ore-forming events may involve fluid packets not captured in modern geothermal sampling and that giant ore deposits can form rapidly from small volumes of metal-rich fluid.
History
Publication title
Scientific ReportsArticle number
2057Number
2057Pagination
1-7ISSN
2045-2322Department/School
School of Natural SciencesPublisher
Nature Publishing GroupPlace of publication
London, UKRights statement
Licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (CC BY-NC-ND 3.0) http://creativecommons.org/licenses/by-nc-nd/3.0/Repository Status
- Open