| Summary: | Author Posting. © American Geophysical Union, 1990. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 95, no. B11 (1990): 17555–17569, doi:10.1029/JB095iB11p17555. The Comer seamounts in the western North Atlantic and Great Meteor seamount “chain” in the eastern North Atlantic are thought to progress in age from Late Cretaceous through late Cenozoic. They both presumably formed by volcanism above the New England hotspot when first the North American plate, and then the Mid-Atlantic Ridge axis and African plate, moved over the hotspot. High-resolution, multibeam bathymetry of the seamounts shows geomorphic features such as guyots, terraces, and a base level plateau (Cruiser plateau) that we interpret to have formed at sea level. We have backtracked these features to sea level along the North Atlantic crustal age-depth curve in order to estimate their ages. The derived age pattern of volcanism indicates formation of the Comer seamounts at ca. 80 Ma to 76 Ma, with migration of the Mid-Atlantic Ridge plate boundary over the hotspot and formation of the Cruiser plateau about 76 Ma. Seamount ages suggest that subsequent volcanism on the African plate moved first northward, in the Late Cretaceous to early Cenozoic (Plato, Tyro, and Atlantis seamount groups), then southward to Great Meteor Seamount in the late Cenozoic. Recurrent volcanism appears to have occurred at some seamounts up to 20–30 m.y. after their initial passage over the hotspot. It would thus appear that intralithospheric conduits can link the hotspot to old seamounts several hundred kilometers away. This work was supported in part by ONR Contract N00014-82-C-0019 to B. Tucholke at Woods Hole Oceanographic Institution.
|
|---|