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EDINSED3D: Evolution of Sedimentary Dynamics during Changes in Climate Regime*
By
R. Urgeles1, B. De Mol1, and A. Camerlenghi1,2
Search and Discovery Article #40278 (2008)
Posted February 7, 2007
*Reprinted, with some modification in format, from AAPG European Region Newsletter, December 2007, v.2 (http://www.aapg.org/europe/newsletters/index.cfm), p. 6, with kind permission of the author and AAPG European Region Newsletter, Hugo Matias, Editor ([email protected]).
1 Dept. D’Estratigrafia, Paleontologia i Geociències Marines, Facultat de Geologia, Universitat de Barcelona ([email protected])
2 Institució Catalana de Recerca i Estudis Avançats
One of the most significant events in the history of Earth's continental margins occurred during the transition from the late Pliocene to the Pleistocene with the initiation of glacial cycles in the northern hemisphere. Such a change in Earth’s climate regime implied evolution from a steady-state landscape (Pliocene) into another one in which glacial and fluvial systems could not attain equilibrium (Pleistocene). The world’s ocean margins, both active and passive, responded to the new climatic regime with an increase in sedimentation rates and grain size in a variety of sedimentary environments (Peinzhen et al., 2001). For instance, Nelson (1990) shows that sedimentation rates in the Ebro margin (NW Mediterranean) were four times larger during the Pleistocene compared to the late Pliocene. Increase in onshore erosion and offshore sedimentation rates in the North Atlantic resulted from glaciation – deglaciation cycles (De Mol et al., 2002), while this resulted from fluvial dynamics in Mediterranean margins. This change in climate regime probably induced important changes in the sedimentary dynamics of continental margins. The manner in which this affected their morphology and the processes of sediment transfer that act on them is still poorly known, at least at a relatively detailed scale.
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EDINSED3D is a project funded by the Spanish Ministry of Education and Science that attempts to better understand the evolution of sedimentary dynamics of canyons and continental margins in general during periods of change in climate regime. To achieve this 3D seismic, well-logging and core data, in combination with 2D seismic, multibeam and side-scan sonar data will be used. EDINSED3D has a marked thematic objective; however, the study will be limited both in time: late Pliocene - Pleistocene boundary, and space: Ebro margin and Porcupine Seabight. In this period, these two margins appear to have a common history of erosive events and sedimentary deposition. In the Ebro margin the control on sedimentary dynamics is exerted by numerous canyons (Figure 1) while in the Porcupine Seabight the controls are exerted by turbidity channels and contourites in close association with cold water coral banks. The latter were also relatively abundant in the Mediterranean during the Pliocene. Near the Pliocene-Pleistocene boundary, Mediterranean cold water coral abundance declined, while cold water coral mounds flourished in the Northeast Atlantic, most probably driven by the Mediterranean Outflow Water (De Mol et al., 2005). The project will particularly try to answer a series of questions related to the upper Pliocene to Pleistocene transition, such as: How submarine canyons responded to the increase in sediment availability and to changes in marine dynamics? Which was their role in sediment transfer? Which was their paleomorphology? Did submarine canyons fill up in the early Pleistocene? Or, to the contrary, were there important erosion or canyon incision events? What was the role of mass sediment transport? Which is the relationship between changes in the Northeast Atlantic and Mediterranean in this period? Is there a relationship between the change in the margin’s sedimentary dynamics and migration of cold water corals from the Mediterranean into the Atlantic?
De Mol, B., Henriet J.P., and Canals, M., 2005, Development of coral banks in Porcupine Seabight: do they have Mediterranean ancestors?, in A. Freiwald and M. Roberts, eds., Deep-water corals and ecosystems: Springer- Verlag. De Mol, B., Van Rensbergen, P., Pillen, S., Van Herreweghe, K., Van Rooij, D., McDonnell, A., Huvenne, V., Ivanov, M., Swennen, R.Y., Henriet, J.P., 2002, Large deep-water coral banks in the Porcupine Basin, southwest of Ireland: Marine Geology, v. 188, p. 193-231. Nelson, C.H., 1990, Estimated post-Messinian sediment supply and sedimentation rates on the Ebro continental margin, Spain: Marine Geology, v. 95, p. 395-418. Peizhen, Z., Molnar, P., and Downs, W.R., 2001, Increased sedimentation rates and grain sizes 2-4 Myr ago due to the influence of climate change on erosion rates: Nature, v. 410, p. 891-897.
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