Jaramillo-Rios J. S., Espinoza-Otayza J. A., Ramirez-Briones J., Valverde-Rodriguez P. E., Vallance J., Tavazzani L., Chelle-Michou C., de Haller A., Chiaradia M., Spikings R. A., Zanetti K. A., Konrad K., Baby Patrice, Melgarejo J. C., Torró L. (2026). The Morococala Volcanic Field, Bolivia : geochemistry and geochronology in the Huanuni district. Journal of South American Earth Sciences, 179, p. 106112 [25 p.]. ISSN 0895-9811.
Titre du document
The Morococala Volcanic Field, Bolivia : geochemistry and geochronology in the Huanuni district
Année de publication
2026
Auteurs
Jaramillo-Rios J. S., Espinoza-Otayza J. A., Ramirez-Briones J., Valverde-Rodriguez P. E., Vallance J., Tavazzani L., Chelle-Michou C., de Haller A., Chiaradia M., Spikings R. A., Zanetti K. A., Konrad K., Baby Patrice, Melgarejo J. C., Torró L.
Source
Journal of South American Earth Sciences, 2026,
179, p. 106112 [25 p.] ISSN 0895-9811
The Central Andes constitute a key natural laboratory for studying the tectono-magmatic response to subduction beneath thick continental crust and the formation of associated ore deposits. In the Bolivian back-arc region, world-class Sn-polymetallic deposits of the Huanuni district are spatially associated with rhyolitic dikes and voluminous peraluminous pyroclastic deposits related to the Morococala Volcanic Field. New geochronological data indicate that the peraluminous rhyolitic dikes in Huanuni were coeval and likely part of the same magmatic plumbing system at ca. 7.0-6.4 Ma, and hence are not associated with the Oligocene-Miocene Sn-polymetallic mineralization (ca. 24 Ma). Mixing models based on Nd-Sr isotopic compositions of the Morococala Volcanic Field, supported by Monte Carlo simulations, suggest crustal contributions of similar to 45-70%. These are, in general, concordant with the similar to 50:50 mantle-derived melts and continental crust mass balance models proposed for other ignimbrite fields of the Neogene Ignimbrite Province of the Central Andes in the back-arc region (e.g., Los Frailes Volcanic Field and the Panizos, Coranzuli, Vilama, and Ramadas fields within the Altiplano-Puna Volcanic Complex). Mineralogical and geochemical evidence suggests that the associated magmas formed under thick-crustal conditions, with garnet as a residual phase. The voluminous rhyolitic magmatism in the Morococala Volcanic Field likely resulted from hot mantle upwelling induced by slab re-steepening of the subducted slab after a flat-slab episode.
Plan de classement
Sciences du milieu [021]
;
Géologie et formations superficielles [064]
Description Géographique
BOLIVIE ; ANDES ; MOROCOCALA VOLCAN
Localisation
Fonds IRD [F B010097359]
Identifiant IRD
fdi:010097359
