Subsurface controls on the development of the Cape Fear Slide Complex, central US Atlantic Margin
Published:September 30, 2019
Jenna C. Hill, Daniel S. Brothers, Matthew J. Hornbach, Derek E. Sawyer, Donna J. Shillington, Anne Bécel, 2019. "Subsurface controls on the development of the Cape Fear Slide Complex, central US Atlantic Margin", Subaqueous Mass Movements and their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides, D.G. Lintern, D.C. Mosher, L.G. Moscardelli, P.T. Bobrowsky, C. Campbell, J. Chaytor, J. Clague, A. Georgiopoulou, P. Lajeunesse, A. Normandeau, D. Piper, M. Scherwath, C. Stacey, D. Turmel
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The Cape Fear Slide is one of the largest (>25 000 km3) 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.
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Subaqueous Mass Movements and their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides
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The challenges facing submarine mass movement researchers and engineers are plentiful and exciting. This book follows several high-profile submarine landslide disasters that have reached the world's attention over the past few years. For decades, researchers have been mapping the world's mass movements. Their significant impacts on the Earth by distributing sediment on phenomenal scales is undeniable. Their importance in the origins of buried resources has long been understood. Their hazard potential ranges from damaging to apocalyptic, frequently damaging local infrastructure and sometimes devastating whole coastlines. Moving beyond mapping advances, the subaqueous mass movement scientists and practitioners are now also focussed on assessing the consequences of mass movements, and the measurement and modelling of events, hazard analysis and mitigation. Many state-of-the-art examples are provided in this book, which is produced under the auspices of the United Nations Educational, Scientific and Cultural Organisation Program S4SLIDE (Significance of Modern and Ancient Submarine Slope LandSLIDEs).