Fig. 3: Caribbean dynamic topography and asthenospheric viscosity analyses.

a Caribbean dynamic topography map from this study overlain on topography. Solid squares show residual topography from Hoggard, White³⁶, which are color-coded to the same dynamic topography scale. Major plate boundaries are shown as red lines. A black open circle shows the location of the proposed slab window²¹. b Full-waveform tomography of Zhu et al.²⁵ at 300 km depth. Gray lines show azimuthal anisotropy that may indicate mantle flow directions. We interpret the eastern edge of the slow anomalies near the Beata ridge (BR) as the leading edge of the hot mantle material passing through the Panama slab window. Colored squares show northward younging back-arc alkaline basalts with Galapagos isotopic signatures that have been interpreted as Galapagos-sourced asthenosphere passing through the slab window²⁶. The black dashed line shows the present leading edge of the slow anomalies; the distance from the black dashed line to the Panama slab window is later used to obtain the flow velocities in Fig. 4. c Dynamic topography plotted as a function of the distance from the slab window shown in (a). Gray dots are obtained from this study (i.e., reflection-constrained basement and gravity-and-seismic constrained Moho). Red dots are robust estimations with both the basement and Moho constrained by seismic. The dynamic topography shows an eastward decreasing trend characterized by ~500 m uplift at the Galapagos, ~300 m uplift near the Panama slab window to ~0 m near the Aves ridge to the east, and 500 m subsidence within the Atlantic. This trend fits with the trend of dynamic topography outside the study area, shown by green dots from Hoggard, White³⁶. e, f are two cross-sections that clearly show ~200 ± 50 km thick asthenosphere from the slower areas colored in red²⁵. Profile locations are shown in (b). Panels (b), (d), and (e) are modified from Figs. 5 and 6 in reference ²⁵.