3-D Modelling of the Dynamical Mechanisms Driving Continental Intra-Plate Volcanism

Volcanic provinces within Earth's continents exhibit a wide range of characteristics that reflect the intricate nature of the dynamic interactions at their origin. To improve our understanding of the driving mechanisms at play, we address the generation of intra-plate continental volcanism by modelling the 3-D interaction between an upwelling mantle plume and a thick lithospheric block. We examine scenarios with and without plate motion and assess the spatio-temporal distribution and intensity of produced melts. Our findings demonstrate the critical role of lithospheric thickness in determining the location and volume of plume-driven magmatic provinces. Building on these results obtained using simplified lithospheric structures, we further apply our numerical methodology to simulate the inferred interaction between the Cosgrove plume and eastern Australia during the past 35 Myr. We design the Australian continent using available 3-D lithospheric architecture determined through seismic tomography and impose the inferred plate motion associated with this region. Our models incorporate updated peridotite melting parameterisations to provide quantitative estimates of generated melt volume and composition. We find that plume-driven and shallow edge-driven melting processes, modulated by the lithospheric thickness of the Australian continent, combine to explain the observed volcanic record. Our preliminary results agree well with surface observations and provide further insight into the geodynamics of eastern Australia.