Supercontinent, large CAMP igneous event, rifting, Atlantic opening. Southeastern North America (SENAM) has been shaped by some of the most significant geologic events of the past ~300 Ma. The area encompasses the South Georgia Basin, the largest buried Mesozoic rift basin in eastern North America; CAMP, one of the largest igneous provinces in the world, recorded in voluminous sills and dikes; and buried sutures that separated North America from Gondwana.

The southeastern margin of North America records large-scale geologic processes responsible for the construction of the continental lithosphere spanning a Wilson cycle, including continental assembly of the Pangaea supercontinent by accretion, mountain building, rift initiation, and the opening of the Atlantic Ocean.

Buried Basement Rocks

All of the basement (crystalline) rocks of Florida, and a sizable portion of the basement rocks of Alabama, Georgia, and South Carolina are buried beneath thick coastal plain sediments. Thus, many rocks that record the final Pangaea supercontinent collision as well as Mesozoic rifting, massive igneous intrusions, and the formation of the Atlantic rifted margin exist only in subcrop.

Because these rocks are not exposed and are known only from limited borehole data, the nature and southeastward extent of southern Appalachian terranes, as well as the Appalachian Suwannee African suture, the South Georgia Rift (SGR) and the Central Atlantic Magmatic Province (CAMP) magmatism remain speculative (Duff, 2020).

The density of boreholes that penetrate pre-Cretaceous basement below the coastal plain is very low; therefore, geophysical surveys have become important for revealing the nature of crustal material and the distribution of Appalachian and Atlantic basement structures and terranes buried here.

Aeromagnetic and Gravity Surveys