From the Bottom Up: Calculating Mantle‐Derived Magma Flux Using Subduction Parameters and Petrologic Constraints at Oceanic Arcs

Abstract Mantle‐derived magma flux has a first‐order control on long‐term volcanic productivity, volatile cycling, and crustal growth in convergent margins. However, the factors controlling it remain unclear. We used a simplified, 3D conceptualization of an intraoceanic subduction zone and petrologic constraints on mantle melting to calculate mantle‐derived magma flux from the “bottom up”, and test the sensitivity of mantle‐derived magma flux to a variety of input variables. Estimates of mantle‐derived flux from our model can be compared to existing “top down” models based on erupted volumes and crustal growth models and is also a jumping‐off point from which more complex models of mantle‐derived magma flux at a variety of scales may be developed. We find that the total volume of mantle available to melt exerts the most significant control on mantle‐derived magma flux between different arcs. At a given arc, convergence rate and the extent of melting have the greatest impact on mantle‐derived magma flux. Variation in flux caused by variations in orthogonal convergence rates within the Aleutians may cause variability in mantle‐derived magma flux along‐arc.