The resulting highland eroded over time, and when North American Plate motion moved the valley away from the hotspot, the resulting thinned lithosphere subsided, forming a trough.
The seismic zones centered on New Madrid, Missouri, and Charleston, South Carolina, and the volcanic kimberlite pipes in Arkansas are cited as evidence.
[4] Other published reports[6][7] argue that the lack of a chain of age-progressive seamounts (as in the Hawaiian-Emperor seamount chain), the absence of present-day volcanism, and the elongation of the Bermuda Rise oblique to plate motion are evidence against a hotspot origin for the Bermuda Rise.
Others[6] alternatively attribute the Bermuda Rise to a reorganization of plate tectonics associated with the closing of the Tethys Sea, though noting that shallow processes may not explain the source of the magmatism.
A still more recent paper,[8] based on geochemical analysis of a drill core, suggests that Bermuda volcanism sampled a transient mantle reservoir in the mantle transition zone that was formed by chemical recycling related to subduction during the formation of Pangaea.