On the tectonic history and origin of the Northeast Georgia Rise

Abstract

Northeast Georgia Rise is located on inferred oceanic crust that is considered Albian in age and to have formed during the separation of Africa and South America. Basalt overlying a weathered regolith was recovered at Site 698 and a basaltic substratum at other sites is inferred from the downhole variation in pore-water chemistry. The provenance of a 2-m-thick gravel bed containing abundant clasts of continental lithologies displaced into lower Oligocene ooze at Site 699 is an enigma. We infer that at least part of the Northeast Georgia Rise was formed at a spreading center by excessive volcanism. At least two episodes of deformation have subsequently modified the topography of the rise. -from Authors