Bermuda hotspot
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The Bermuda hotspot is a spot in the Atlantic Ocean east of Bermuda. As a geologic hotspot, it is a place where magma rises from the Earth's mantle to the crust. Vulcanism from this hotspot created the island of Bermuda, and the Bermuda rise, a feature of the Atlantic seafloor, also east of Bermuda.
Writing in the January 2007 issue of Scientific American [1], Roy B. Van Arsdale and Randel Cox of the University of Memphis set out the evidence of how the Bermuda hotspot caused the Mississippi embayment. They explain:
As Pangaea began to break up about 95 million years ago, North America passed over a volcanic "hot spot" in the earth's mantle (specifically, the Bermuda hot spot) that was undergoing a period of intense activity. The upwelling of magma from the hot spot forced the further uplift to a height of perhaps 2-3 km of part of the Appalachian-Ouachita range, forming an arch. The uplifted land quickly eroded and, as North America moved away from the hot spot and as the hot spot's activity declined, the crust beneath the embayment region cooled, contracted and subsided to a depth of 2.6 km, forming a trough that was flooded by the Gulf of Mexico. As sea levels dropped, the Mississippi and other rivers extended their courses into the embayment, which gradually became filled with sediment.
Evidence for the Van Arsdale-Cox explanation is found in the presence of the seismic zones centered on New Madrid, Missouri, and Charleston, South Carolina, each the source of devastating earthquakes in the 19th century, and in diamond-bearing kimberlite pipes in Arkansas, which are products of volcanism.
