The 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.

馈送超喷发的岩浆系统是由深部的高岩浆供应产生的，该岩浆在浅地壳中维持了大范围的部分熔融。然而，围绕超大型岩浆系统发展的过程和时间尺度仍然存在许多问题。我们介绍了新的锆石年龄，杰麦斯山脉火山场（JMVF）的痕量元素和同位素数据，揭示了形成对比的岩浆过程，这些岩浆过程导致了在1.60和1.25 Ma处的流纹岩超喷发。在超火山爆发之前，从约8.4密耳以上的熔岩中喷出的锆石主要具有单峰年龄分布，接近其各自的喷发年龄。这突显了JMVF地壳中逐渐形成了独特的岩浆区域。锆石晶体的继承性表明该岩浆来自于第一次超喷发。60 Ma包括至少3个这些前驱体岩体和基底岩石，它们通过〜2 Ma的岩浆供应增加而部分熔融。相反，从1.25 Ma的第二次超级喷发起，没有遗留的锆石和火成岩中的锆石化学成分发生变化，这表明旧岩浆储层的残余物发生了热复位，并迅速构造了一个新的超大型岩浆体。年轻的JMVF中喷发行为的突然变化反映了地壳的热和化学成熟，以及岩浆供应增加和前体海藻的部分融化。我们的研究强调，尽管地壳条件调节可能发生在数百万年的渐进岩浆运动中，但超大型岩浆体的组装发生的时间要快得多，并且可能由于撤离后的热调节而连续发生。