Wu, JieCronin, ShaneRowe, Michael CWolff, John ABarker, SimonFu, BinBoroughs, Scott2022-10-310024-4937http://hdl.handle.net/1885/276782The magmatic systems that feed supereruptions result from high magma supply from depth that sustains large regions of partial melt in the shallow crust. However, many questions remain around the processes and timescales over which super-sized magmatic systems develop. We present new zircon age, trace elemental and isotopic data from the Jemez Mountains volcanic field (JMVF) to reveal contrasting magmatic processes that led to successive rhyolitic supereruptions at 1.60 and 1.25 Ma. Before the supereruptions, zircons from lavas erupted over ~8.4 Myr have predominantly unimodal age distributions, close to their respective eruption ages. This highlights that distinct magma domains gradually formed in the JMVF crust. Zircon crystal inheritance shows that magma from the first supereruption at 1.60 Ma included at least three of these precursor plutons and basement rock that were partially molten by enhanced magma supply from ~2 Ma. In contrast, absence of inherited zircon and a change in zircon chemistry in ignimbrite from the second supereruption at 1.25 Ma indicates a thermal resetting of the remnants of the old magma reservoir and rapid construction of a new super-sized magma body. The sudden change in eruptive behaviour in the young JMVF reflects both thermal and chemical maturation of the crust, as well as elevated magma supply and partial melting of precursor plutons. Our study highlights that although crustal conditioning may occur during gradual magmatism over millions of years, the assembly of super-sized magma bodies occurs over much faster timescales and may occur in succession due to thermal adjustment following evacuation.We acknowledge technical supports from William Phillips, Natalia Abrego, David Wackrow, Andrew Canada, Kirsty Vincent, David Flynn and Andres Arcila-Rivera with sample preparation, Stuart Morrow with LA-ICP-MS analysis. We thank Mark Fanning for both preparation of zir- con mounts and help with zircon U–Pb dating. We appreciate the con- structive review and useful suggestions from Axel Schmitt, Mariek Schmidt, and Olivier Bachmann (on an early version of this manuscript). This research was supported by the MBIE Resilience to Nature's Chal- lenges, Volcanic Hazards Theme (to S.J.C.), the University of Auckland School of Environment PBRF funds and R&SL support (to M.C.R.), as well as the University of Auckland PReSS account and China Scholarship Council scholarship no. 201506400051 (to J.W.). J.W. and S.J.C. acknowl- edge support of the Transitioning Taranaki to a Volcanic Future MBIE Endeavour Research Program UOAX1913.application/pdfen-AU© 2021 Elsevier B.VRhyolitic supereruptionCalderaZirconMagmatismPartial melting202110.1016/j.lithos.2021.1062012021-11-28