Crustal magma plumbing system beneath the Taupō Volcanic Zone of New Zealand

How structural elements govern magmatic differentiation in the crust remains unclear, particularly in volcanic systems that exhibit substantial lithological diversity. The Taupō Volcanic Zone of New Zealand represents a premier example of such complexity, as it displays pronounced spatial and temporal transitions between andesitic and silicic volcanism. However, a high-resolution seismic framework for its magmatic plumbing system remains elusive, hindering a comprehensive understanding of the mechanisms driving these petrological shifts. Here, we examine crustal velocity structures beneath the Taupō Volcanic Zone by employing a new adjoint-state differential traveltime tomography method and an extensive dataset comprising traveltime picks accumulated over the past 40 years. Our final velocity model reveals the fundamental role of an intact and impermeable upper crustal lid in controlling the vertical distribution and maturation of magma in the crust. The mechanical state of this lid effectively dictates the storage levels of less-evolved melts, whereas its structural degradation due to extension and thermal erosion facilitates magma ascent and the subsequent development of more differentiated, shallow reservoirs. These findings provide a plausible framework for understanding the transition between different magmatic styles and offer new insights into the mechanisms driving the spatial and temporal evolution of arc and rift systems globally.