The rise and fate of a long-lived deep crustal ‘hot zone’ beneath the neogene-quaternary Cordillera de San Buenaventura in the Southern Puna Plateau (NW Argentina)

ABSTRACT

Arc magmatism plays a key-role in the growth and differentiation of continental crust. In particular, the prolonged magmatic flux events control the genesis of deep crustal hot zones where magma accumulation and fractionation favour the continental arc crust evolution and geochemical stratification. In this view long-lived magmatic systems located in arc domains, with their erupted products spanning from basalts to rhyolites are formidable archive for the understanding the evolution of transcrustal magmatic plumbing systems and the construction of a stratified continental crust. This study focuses on the long-lived (ca. 9 Ma) Miocene-Holocene Cordillera de San Buenaventura volcanic system in the Southern Puna Plateau (NW Argentina), a unique natural laboratory where exploring the building up of MASH-zones (or deep crustal ‘hot zones’) and related sustained volcanism. Synthesis of new and published data, together with new thermobarometry and fractional crystallization modelling, indicates a cyclic scenario with mantle melts undergoing fractional crystallization dominated incipient and waning stages alternate to major mafic magma recharge events during the building up phase of the MASH-zone. This magmatic scenario is also discussed in the light of the coeval geodynamic framework dominated by the subduction of the Nazca plate and the eastward migration of the frontal arc magmatism.

GRAPHICAL ABSTRACT

KEYWORDS:

• Crustal hot zone
• MASH
• magmatic plumbing system
• Southern Puna plateau
• andes
• central volcanic zone
• Nazca plate subduction

Acknowledgments

LB gratefully acknowledges G. de Souza Franco, the entire team of the “Laboratorio de Microscopía Electrónica y Análisis por Rayos X” (LAMARX) of the National University of Córdoba (Argentina) and that of the “Laboratorio de Microssonda Electrônica” of the Brasilia University (Brasil) for their contributions to the electron microprobe measurements. LB is also grateful to the “Instituto para la Bio- y Geo-Ciencias del NOA” (IBIGEO) of the National University of Salta (Argentina) and the “Consejo Nacional de Investigaciones Científicas y Técnicas” (CONICET; Argentina) for supporting this investigation. We gratefully thank W. Báez for the useful discussion during early manuscript preparation. FL thanks J.C. White for advice on the fractional crystallization modelling. Lastly, LB sincerely thanks S. de Silva for his contribution to the revision of this manuscript. The constructive reviews of S. Kay and an anonymous reviewer as well as the professional handling of the Editor R.J. Stern greatly contributed to improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Credit

LB and FL: Conceptualization and Visualization; LB and FL: Methdology; LB: Formal analysis – thermobarometry modelling; FL: Formal analysis – FC and R-FC modelling; LB, MA, EB, RF and AV: Field work; LB, MA and EB: Investigations, Data curation and Resources; MA and RB: Project administration and Funding acquisition; JV: Supervision; LB performed Writing – Original Draft; FL performed Writing - Review & Editing. LB and FL prepared the paper with contributions from all the co-authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00206814.2022.2145511

Additional information

Funding

This study was financially supported by the PICT 2014-3436 ‘Petrogénesis de magmas vinculados a un sistema magmáticos de larga duración, Mioceno Medio-Holoceno, en el límite austral de la Puna. Complejos Volcánicos La Hoyada y Cerro Blanco, provincia de Catamarca’.