Title Late Neogene to recent sea floor instability on the deep Pacific margin of the Antarctic Peninsula
Author Volpi, V.; Amblas, D.; Camerlenghi, A.; Canals, M.; Rebesco, M.; Urgeles, R.
Author Affil Volpi, V., Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Sgonico, Italy. Other: University of Colorado at Boulder; Chevron Energy Technology; Universitat de Barcelona, Spain; Institut de Ciencies del Mar, Spain
Source Mass transport deposits in deep-water settings, edited by R.C. Shipp, P. Weimer and H.W. Posamentier. Special Publication - Society for Sedimentary Geology, Vol.96, p.161-177. Publisher: Society for Sedimentary Geology (SEPM), Tulsa, OK, United States. ISSN: 1060-071X. ISBN: 978-1-56576-287- 9
Publication Date Apr. 2011
Notes In English. 64 refs. GeoRef Acc. No: 309944
Index Terms Antarctica--Antarctic Peninsula; Ocean Drilling Program--ODP Site 1096; Ocean Drilling Program--ODP Site 1101; Southern Ocean; Antarctic Peninsula; Antarctica; bathymetry; Cenozoic; clastic rocks; clastic sediments; clastic wedges; continental slope; contourite; currents; deep-water environment; deposition; depositional environment; diamicton; failures; geophysical methods; geophysical surveys; Holocene; Leg 178; marine environment; marine methods; marine sedimentation; mass movements; Neogene; Ocean Drilling Program; ocean floors; ODP Site 1096; ODP Site 1101; offshore; Pacific Plate; paleoenvironment; petroleum; petroleum exploration; plate boundaries; plate tectonics; progradation; Quaternary; reflection methods; sediment transport; sedimentary rocks; sedimentation; sedimentation rates; sedimentology; sediments; seismic methods; slope stability; sorting; surveys; Tertiary; transport; traps; turbidite; turbidity currents; upper Neogene
Abstract Sediment mass transport in the Pacific margin of the Antarctic Peninsula is strongly influenced by its peculiar tectonic and sedimentary evolution. Analysis of swath bathymetry and multichannel seismic reflection data shows that this setting reflects the passage from an active to a passive margin, and the transition from river- dominated to glacier-dominated sedimentation. Only contouritic sedimentation persisted throughout the late Neogene on the continental rise, while rapid progradation of steep wedges composed of glacial diamicton occurs on the slope. Gravitational instability and mass-transport processes, which occur on the continental rise, appear to relate to physical properties of contourite sediments deposited in this high- latitude setting. Other than minor erosional gullies on the upper slope, there is no evidence of major incisions such as channels, canyons, or slide scars on a steep continental slope (averages 13). This situation results from high shear strength of the slope-forming diamicton delivered by grounded ice sheets. Short-run-out mass failures were the main sediment transport process to the slope. Turbidity currents, most likely originated by downslope evolution of mass flows, were able to generate large deep-sea channel systems at the base of the continental slope. On the continental rise, relatively good sorting and a high accumulation rate of sediments forming sediment drifts favored slope failure even on gentle slopes. Coalescent headscarps that form the drift crest were produced by undercutting of steeper flanks of drifts. This process formed the walls of turbidity- current channels, flowing in low-relief areas between drifts. Failure along stratal weak layers on the gentle sides of sediment drifts produced either relatively small, concave slide scars in the margin-proximal drift or long, rectilinear scars in distal locations.
Publication Type journal article
Record ID 91498