NEW INSIGHTS ON TRANSFER ZONES IN THE SOUTH GEORGIA RIFT BASIN, SOUTHEASTERN U.S

Integration of new seismic reflection data with existing well and potential ­field data document (1) a reversal of rift basin asymmetry across the Warner Robins Transfer Zone, (2) identi­fication of the (related?) Hazlehurst Transfer Zone, and (3) the presence of a new stratigraphic unit (informally named the Hazlehurst Formation) which sits below the Coastal Plain unconformity and with angular unconformity above an inferred Triassic rift basin (Valdosta Basin).

Triassic rifting of the supercontinent Pangea left behind numerous basins on what is now the eastern North American margin. The South Georgia Rift (SGR) was thought to be the best preserved of these basins having been capped by thick basalt flows of the Central Atlantic Magmatic Province (CAMP) and later buried beneath the Cretaceous and younger Coastal Plain. Because it is buried beneath the Coastal Plain, the SGR is only known through sparse drilling and geophysical methods. With the new seismic data acquired in 2013 near Hazlehurst, Georgia, we are able to put more constraints into the tectonic history of the basin.

We test three major hypotheses related to the SGR: (1) the Valdosta Basin has a further extent to the northeast; (2) the “Transfer Zone” had to exist to transmit extensional strain between rift sub-basins with reverse polarities, and the Hazlehurst Transfer zone had truncated the newly identifi­ed Valdosta Basin; (3) reanalysis of existing well and seismic data shows there is a sub-horizontal layer “Hazlehurst Formation” existing on the top of the Triassic basin and below the “J” horizon that has never been identifi­ed. The result of the studies suggest that the previous understanding of the SGR is challenged by the new discoveries about the stratigraphy under the coastal plain.