Abstract The Cape Fear Slide is one of the largest (>25 000 km 3 ) submarine slope failure complexes on the US Atlantic margin. Here we use a combination of new high-resolution multichannel seismic data (MCS) from the National Science Foundation Geodynamic Processes at Rifting and Subducting Margins (NSF GeoPRISMS) Community Seismic Experiment and legacy industry MCS to derive detailed stratigraphy of this slide and constrain the conditions that lead to slope instability. Limited outer-shelf and upper-slope accommodation space during the Neogene, combined with lowstand fluvial inputs and northwards Gulf Stream sediment transport, appears to have contributed to thick Miocene and Pliocene deposits that onlapped the lower slope. This resulted in burial of an upper-slope bypass zone developed from earlier erosional truncation of Paleogene strata. These deposits created a broad ramp that allowed accumulation of thick Quaternary strata across a low-gradient (<3.5°) upper slope. Upslope of one of the larger headwalls, undulating Quaternary strata appear to downlap onto a buried failure plane. Many of the nested headwalls of the upper-slope portion of slide complex are underlain by deformed strata, which may be the result of fluid migration associated with localized subsidence from salt migration. These new data and observations suggest that antecedent margin physiography, sediment loading and substrate fluid flow were key factors in preconditioning the Cape Fear slope for failure.

Abstract The surface and near-surface geology of the Atlantic Coastal Plain from Cape Fear, North Carolina to Cape Canaveral, Florida, below 76 m (250 ft) in altitude, comprises Pliocene and Pleistocene fluvial marine, back-barrier, barrier, and shallow-shelf sand, silt, and clay. The fossil content of age-equivalent Pliocene and Pleistocene sediments decreases from the Cape Fear area southward into Georgia. In the Carolinas, fossils are common. Paleontological analyses and isotopic and chemical age determinations, combined with lithostratigraphic studies and geologic mapping, have resulted in the establishment of a regional time-stratigraphic framework. In Georgia, fossils are scarce. Most known fossil localities are in early late Pliocene sediments paleontologically dated between 3.5 and 2.8 Ma. Microfossil data suggest the presence of at least two other Pliocene units—late early Pliocene (4.2-4.0 Ma) and latest late Pliocene (2.4-1.8 Ma). Fossil data are insufficient to differentiate Pleistocene units, but there are distinctive changes in shell morphology and species abundance of foraminifera in sediments topographically above and topographically below 9 m (30 ft) in altitude. No isotopic or paleomagnetic data are available for Pliocene or Pleistocene sediments in Georgia. There has been no detailed geologic mapping. Regional mapping dates to the turn of the century. The fossil-poor nature of both onshore and offshore Pliocene and Pleistocene Coastal Plain sediments in the Georgia part of the Atlantic Coastal Plain may be due to any one or combination of the following: styles and rates of regional and/or local uplift; sediment load of the numerous rivers that drain this region; freshwater influence on estuarine and nearshore littoral environments; shoreline configuration relative to major ocean currents; dissolution as the result of weathering, and erosion.