The interaction between mantle plumes and lithosphere and its surface expressions: 3-D numerical modelling

Abstract

Summary The rise of mantle plumes to the base of the lithosphere leads to observable surface expressions, which provide important information about the deep mantle structure. However, the process of plume-lithosphere interaction and its surface expressions remain not well understood. In this study, we perform 3-D spherical numerical simulations to investigate the relationship between surface observables induced by plume-lithosphere interaction (including dynamic topography, geoid anomaly and melt production rate) and the physical properties of plume and lithosphere (including plume size, plume excess temperature, plume viscosity, and lithosphere viscosity and thickness). We find that the plume-induced surface expressions have strong spatial and temporal variations. Before reaching the base of the lithosphere, the rise of a plume head in the deep mantle causes positive and rapid increase of dynamic topography and geoid anomaly at the surface but no melt production. The subsequent impinging of a plume head at the base of the lithosphere leads to further increase of dynamic topography and geoid anomaly and causes rapid increase of melt production. After reaching maximum values, these plume-induced observables become relatively stable and are more affected by the plume conduit. In addition, whereas the geoid anomaly and dynamic topography decrease from regions above the plume center to regions above the plume edge, the melt production always concentrates at the center part of the plume. We also find that the surface expressions have different sensitivities to plume and lithosphere properties. The dynamic topography significantly increases with the plume size, plume excess temperature and plume viscosity. The geoid anomaly also increases with the size and excess temperature of the plume but is less sensitive to plume viscosity. Compared to the influence of plume properties, the dynamic topography and geoid anomaly are less affected by lithosphere viscosity and thickness. The melt production significantly increases with plume size, plume excess temperature and plume viscosity, but decreases with lithosphere viscosity and thickness.

Robust Seismic Images of the Hawaiian Plume

“…We deem that this feature reflects the lithosphere re-cooling (re-aging) away the Hawaii hotspot after the rejuvenation. This feature was not revealed by any previous tomographic models, but just suggested by numerical simulations (e.g., Ballmer et al, 2013;Ribe & Christensen, 1999;Wang & Li, 2021). Previous two-station measurements of Rayleigh-wave data show that the Pacific lithosphere has a normal thickness of ∼100 km between Midway Atoll and Oahu Island along the Hawaiian island chain (Woods & Okal, 1996), which generally agrees with our present results.…”

“…Recent 3‐D numerical simulations (Wang & Li, 2021) showed that dynamic topography and geoid anomaly decrease from the plume center to the edge, and melt production always concentrates at the plume center. Taking into account the numerical simulation results (Wang & Li, 2021), we deem that the lithosphere re‐aging process revealed by our tomography (Figure 3) is mainly controlled by the plume size, plume excess temperature and the motion of the Pacific lithosphere. The robust 3‐D Vs model (Figures 2–4) may help to produce a better simulation result and improve our understanding of the plume‐lithosphere interactions.…”

“…Previous two‐station measurements of Rayleigh‐wave data show that the Pacific lithosphere has a normal thickness of ∼100 km between Midway Atoll and Oahu Island along the Hawaiian island chain (Woods & Okal, 1996), which generally agrees with our present results. Recent 3‐D numerical simulations (Wang & Li, 2021) showed that dynamic topography and geoid anomaly decrease from the plume center to the edge, and melt production always concentrates at the plume center. Taking into account the numerical simulation results (Wang & Li, 2021), we deem that the lithosphere re‐aging process revealed by our tomography (Figure 3) is mainly controlled by the plume size, plume excess temperature and the motion of the Pacific lithosphere.…”

CitcomSVE: A Three‐Dimensional Finite Element Software Package for Modeling Planetary Mantle’s Viscoelastic Deformation in Response to Surface and Tidal Loads

“…This may have contributed to some of the errors, given that the semi‐analytical solutions are computed up to degrees and orders 100. Wang and Li (2021) used a direct integration method to compute the potential, and future studies may explore the efficacy of this method in CitcomSVE for GIA modeling.…”

A record of plume-induced plate rotation triggering subduction initiation

“…This early rifting typically is interpreted to indicate that the plume migrated along the base of the lithosphere into a pre-existing rift that formed independently of plume rise 27 . However, in numerical simulations dynamic uplift 42 and plume push 41 already start to accelerate plates 10-15 Myr before the plume head reaches the base of the lithosphere and emplaces the LIP. Numerical simulations thus predict the observed delay between plume push, as a driver for early rifting and subduction initiation, and LIP eruption and emplacement.…”