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Longevity and Thermal Evolution of the Magmatic System Associated with the Cerro Blanco Volcanic Complex, Southern Puna: Insights from Zircon Petrochronology

Walter A. Báez (1)(2), Shanaka de Silva (1), Alejandro Cisneros de León (1), Agostina Chiodi (1)(2), Axel Schmitt (3) (4) and Martin Danisik (3)

  • Affiliations:  (1) College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331-5503, USA.(2) IBIGEO (UNSa -- CONICET), Av. Bolivia 5150, A4400FVY Salta, Argentina (3) John de Laeter Centre, Curtin University, Perth, WA, 6845, Australia (4)Insitute of Earth Sciences, Heidelberg University, Germany 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 282

  • Programme No: 1.3.24

  • Theme 1 > Session 3

Abstract

A central question in any effort to understand how large explosive eruptions (VEI ≥6) are generated is: How are the magma bodies that feed such eruptions assembled, and how long do they persist within the crust? Answering this requires understanding the longevity and accumulation rates of magma within the reservoir, as well as the temporal variations in the thermal state of the system (cold vs. hot storage). While geophysical studies provide a snapshot of the architecture of current magmatic systems, geological, geochronological, and petrochemical data allow us to understand the long-term evolution of these systems and the physical conditions that characterize both inter-eruptive and eruptive periods within their evolution. This contribution present zircon petrochronology results from the Cerro Blanco Volcanic Complex (Upper Pleistocene -- Holocene), located in the Southern Puna. This volcanic center is one of the youngest and most productive rhyolitic caldera systems in the Central Volcanic Zone of the Andes (CVZ), with at least two eruptions (VEI ≥6) in the past 30,000 years. Our results indicate that all products of the Cerro Blanco Volcanic Complex were generated from a single long-lived reservoir (≥ 350 ka), which, while geochemically and isotopically homogeneous, was characterized by a complex thermal history, including marked contemporaneous internal heterogeneities. These internal variations, along with episodes of interstitial melt extraction during periods of high crystallinity in the system, explain the entire geochemical and textural variability within the eruptive products of the Cerro Blanco Volcanic Complex and their zircon populations.