The Morococala Volcanic Field, Bolivia : geochemistry and geochronology in the Huanuni district 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. Ignimbrite Peraluminous magmatism Neogene ignimbrite province of the Central Andes Central Andean tin belt Geochronology 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. 2026 text https://www.documentation.ird.fr/hor/fdi:010097359 fdi:010097359 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.. The Morococala Volcanic Field, Bolivia : geochemistry and geochronology in the Huanuni district. 2026, 179, 106112 [25 p.] EN BOLIVIE ANDES MOROCOCALA VOLCAN