Sediment drifts and deep-sea channel systems, Antarctic Peninsula Pacific Margin
Published:January 01, 2002
M. Rebesco, C. J. Pudsey, M. Canals, A. Camerlenghi, P. F. Barker, F. Estrada, A. Giorgetti, 2002. "Sediment drifts and deep-sea channel systems, Antarctic Peninsula Pacific Margin", Deep-Water Contourite Systems: Modern Drifts and Ancient Series, Seismic and Sedimentary Characteristics, D. A. V. Stow, C. J. Pudsey, J. A. Howe, J.-C. Faugères, A. R. Viana
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Twelve sedimentary mounds are identified on the upper continental rise of the Pacific Margin of the Antarctic Peninsula. All these mounds are produced by a varying degree of interaction of along-slope bottom water flow with down-slope turbidity currents. These mounds provide a complete range of intermediates between two end members: the sediment drift and the channel levee. Surface sediments on drift 7 suggest that the mechanisms for the supply and transport of sediment include entrainment of material from turbidity currents within ambient bottom currents, and pelagic settling from the sea surface, including biogenic and glacially derived material. The long-lasting activity of these mechanisms is documented by the data provided by four DSDP and ODP drill sites. Bathymetric and seismic data, both at a large, comprehensive scale and at a small, detailed scale, show the geometry of the sedimentary mounds and their relationships with the adjacent turbidity current channel systems. These data allow the determination of some diagnostic criteria to identify the sediment drifts.
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Deep-Water Contourite Systems: Modern Drifts and Ancient Series, Seismic and Sedimentary Characteristics
Countourites are a widespread but poorly known group of sediments linked to the action of powerful bottom currents in deep water. Although we know they are especially common along continental margins and through oceanic gateways, they have been surrounded by contoversy since they were first recognized in the early 1960s. Where correctly recognized and decoded they can provide one of the keys to our better understanding of bottom water circulation and of the ocean–climate link. They are part of the spectrum of deposits that confronts the oil industry as exploration moves into progressively greater water depths.
This memoir is an important outcome of the International Geological Correlation Project 432 on Bottom Currents, Contourites and Palaeocirculation. It includes 30 papers involving over 75 key scientists from around the world. Following an introductory state–of–the–art paper by the editors, there are 25 separate case studies on modern drifts and four on ancient contourite series. Each contribution highlights the specific geological and oceanographic setting, bathymetry, physiographic and stratigraphic context, seismic attributes and sedimentary characteristics of that drift. Case studies range from some of the well-documented North Atlantic drifts to those much less known from the Mediterrenean, from important syntheses of the Gulf of Cadiz and Vema Channel Gateway, to completely new data on South Atlantic, Pacific and Antartic margin systems. The four papers on ancient series from Japan, China and Cyprus serve to emphasise the complex nature and subtle characteristics of contourites, which make their identification a scientific challenge.
This volume is dedicated to the memory of Charlie Hollister (1936–1999), one of the founding fathers and pioneers of countourite research.