Seamounts Formation due to Deep Mantle Plume Heating

Intraplate volcanic events provide important insights into the dynamic evolution of the Earth's interior. In the ocean, an age-progressive seamount chain is traditionally attributed to the lithosphere moving over a stationary mantle plume. However, many seamounts are spatially scattered without clear age progression, and their relationships to deep mantle processes remain contentious. Here we argue that all seamounts, either with or without age progression, were produced by deep plume-related activities. By developing high-resolution mantle convection models with data assimilation, we predict the present mantle plume structures consistent with recent seismic tomography. In addition, we reproduce the age trends of major hotspot tracks since the Cretaceous. In our model, most Cretaceous seamounts in the Pacific Ocean formed above major plume heads ponding beneath the young oceanic plate, where the resulting hotspot zones fueled widespread intraoceanic volcanism without age progression. Subsequently, the aging and expanding Pacific plate covers more plume conduits from the shrinking neighboring plates, forming the observed Cenozoic age-progressive hotspot tracks above the narrow plume tails. We further show that the widespread and long-lived residual thermal anomalies, which we refer to as seamount brewing zones, eventually form small-volumed seamounts far away from hotspots.