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Boletín de la Sociedad Geológica Mexicana Volumen 72, núm. 3, A260520, 2020 |
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Short note
The Pliocene Xoconostle high sulfidation epithermal deposit in the Trans-Mexican Volcanic Belt: Preliminary study
El depósito epitermal de alta sulfuración pliocénico Xoconostle en la Faja Volcánica Trans-Mexicana:
Estudio preliminar
Edith Fuentes-Guzmán1,2,3, Antoni Camprubí1,*, Janet Gabites4, Eduardo González-Partida5,
Vanessa Colás1
1 Instituto de Geología, Universidad Nacional Autónoma de México. Ciudad Universitaria, 04510 Coyoacán, CDMX, Mexico.
2 Programa de Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México. Ciudad Universitaria, 04510 Coyoacán, CDMX, Mexico.
3 Laboratorio Nacional de Geoquímica y Mineralogía (LANGEM). Ciudad Universitaria, 04510 Coyoacán, CDMX, Mexico.
4 Pacific Centre for Isotopic and Geochemical Research, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia; Earth Sciences Building, 2207 Main Mall, Vancouver, British Columbia, V6T 1Z4, Canada.
5 Centro de Geociencias, Universidad Nacional Autónoma de México. Boulevard Juriquilla 3001, 76230 Juriquilla, Querétaro, Mexico.
* Corresponding author: (A. Camprubí) This email address is being protected from spambots. You need JavaScript enabled to view it.
How to cite this article:
Fuentes-Guzmán, E., Camprubí, A., Gabites, J., González-Partida, E., Colás, V., 2020, The Pliocene Xoconostle high sulfidation epithermal deposit in the Trans-Mexican Volcanic Belt: Preliminary study: Boletín de la Sociedad Geológica Mexicana, 72 (3), A260520. http://dx.doi.org/10.18268/BSGM2020v72n3a260520
Abstract
The Xoconostle prospect in northeastern Michoacán state, south-central Mexico, is constituted by high sulfidation epithermal breccias and stockworks with Au and Hg prospective anomalies. The mineralization is hosted by latest Miocene to Pliocene rocks grouped into the El Terrero ignimbrite and the Siete Cruces dome complex and a stock of intermediate composition and undetermined (Pliocene?) age. Two alunite samples from deep hypogene advanced argillic alteration assemblages within the deposit yielded 40Ar/39Ar ages at 5.57 ± 0.44 (Messinian) and 3.67 ± 0.20 Ma (Zanclean). Such ages are in good agreement with those of volcanic rocks at a semi-regional scale, especially those associated with the nearby Amealco caldera. Assuming that the formation of Xoconostle deposit could be genetically related to any of the eruptive units in this caldera, it would be associated with dacitic-andesitic rocks at ~4.7 Ma or with bimodal andesite-basalt volcanism at ~3.7 Ma, with which rhyolites at the southwest rim of the caldera (nearer to the epithermal deposit) are contemporaneous. The obtained ages are also in good agreement with those determined for the youngest stages in the evolution of the Trans-Mexican Volcanic Belt (TMVB). In addition, such ages compare well with those established for the E-W striking Morelia-Acambay normal fault zone (or Acambay graben). The occurrence of E-W structural features in the study area support their correlation with those in the Acambay graben. Although the metallogenesis of the TMVB needs further endeavours that contribute to its understanding, the Xoconostle prospect adds up to other dated magmatic-hydrothermal deposits that may collectively constitute a Pliocene metallogenic province whose inception was geologically circumscribed to this volcanic arc. However, this and its companion papers in this issue confirm the metallogenic potential of the TMVB in most of its stages of evolution, particularly in the late Miocene-Pliocene stage of acid and bimodal volcanism.
Keywords: Epithermal, high sulfidation, 40Ar/39Ar ages, alunite, Pliocene, Mexico, Trans-Mexican Volcanic Belt, regional metallogeny.
