Continental breakup facilitated by lower crustal magmatism

The role of magmatism in modulating continental breakup remains a topic of debate¹. We present new, high-resolution 3D seismic reflection data from the South China Sea that reveals voluminous lower crustal magmatism occurred ~7–10 Myr before breakup along a >1,000 km long, NE–SW trending belt offset 100 km landwards of the eventual continental rupture. Through integration with numerical geodynamic models of continental extension, we show that a thermal anomaly associated with such lower crustal magmatic intrusion facilitate continental breakup. Specifically, our models show focused magma intrusion weakens the crust, promoting strain localization and migration that can lead to continental rupture 10’s–100’s km away from the site of initial magmatism.