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External forcing and self-organization of clastic shelf systems
T. Hanebuth, H. Westphal, T. von Dobeneck,
M. Elvert, T. Frederichs, R. Henrich, H. Lantzsch, H. Müller, R. Rendle-Bühring, T. Schwenk, V. Spieß
Clastic shelf systems are both major sinks and major source areas on the sediment pathway. Particle storage and release, but also in-situ production, are balanced in delicate, non-steady state equilibria. The very dynamic nature of shelves finds its geological expression in a large lateral variability and frequent discontinuity in the sedimentary record that is usually attributed to external forcing by tectonics and climate, exerted by sea level change, and type and availability of the terrigenous input. However, shelf systems show also considerable self-organization by the interplay of bathymetry, wave and current regimes. These control biological production and clastic sediment distribution – that, in turn, can modify the physical boundary conditions. Biological and physico-chemical processes near the sediment-water interface can vary sediment stability (e.g. by burrowing and remineralization). Such internal controls are highly relevant for process studies, conceptual and numerical models and observatory design as they are not captured by common water column studies regarding the physical setting.
This project investigates the making and shifting of equilibrium states focusing on key sections of three modern, non-glaciated clastic shelf systems with present-day humid to arid conditions, from which substantial stratigraphic, bathymetric, seismic and oceanographic information and large sample sets exist from own previous and ongoing work (off NW Iberia, Uruguay, Mauritania). Objectives of this project are:
1) to assess typical features and transient zones of estuaries, mud belts, shelf break and adjacent upper continental slope from regional down to sub-meter resolution, and
2) to derive sediment flux estimates and material budgets.
Our methological strategy is to combine sedimentological (siliciclastic and carbonate), geophysical and geochemical methods based on high-resolution sampling, benthic profiling and mooring. Expeditions to all three shelves are scheduled for focused seismoacoustic exploration, sediment sampling and use of the expanded functionality of the MARUM-built neritic profiler GEM Shark (First results).
M. Elvert, T. Frederichs, R. Henrich, H. Lantzsch, H. Müller, R. Rendle-Bühring, T. Schwenk, V. Spieß
Clastic shelf systems are both major sinks and major source areas on the sediment pathway. Particle storage and release, but also in-situ production, are balanced in delicate, non-steady state equilibria. The very dynamic nature of shelves finds its geological expression in a large lateral variability and frequent discontinuity in the sedimentary record that is usually attributed to external forcing by tectonics and climate, exerted by sea level change, and type and availability of the terrigenous input. However, shelf systems show also considerable self-organization by the interplay of bathymetry, wave and current regimes. These control biological production and clastic sediment distribution – that, in turn, can modify the physical boundary conditions. Biological and physico-chemical processes near the sediment-water interface can vary sediment stability (e.g. by burrowing and remineralization). Such internal controls are highly relevant for process studies, conceptual and numerical models and observatory design as they are not captured by common water column studies regarding the physical setting.
This project investigates the making and shifting of equilibrium states focusing on key sections of three modern, non-glaciated clastic shelf systems with present-day humid to arid conditions, from which substantial stratigraphic, bathymetric, seismic and oceanographic information and large sample sets exist from own previous and ongoing work (off NW Iberia, Uruguay, Mauritania). Objectives of this project are:
1) to assess typical features and transient zones of estuaries, mud belts, shelf break and adjacent upper continental slope from regional down to sub-meter resolution, and
2) to derive sediment flux estimates and material budgets.
Our methological strategy is to combine sedimentological (siliciclastic and carbonate), geophysical and geochemical methods based on high-resolution sampling, benthic profiling and mooring. Expeditions to all three shelves are scheduled for focused seismoacoustic exploration, sediment sampling and use of the expanded functionality of the MARUM-built neritic profiler GEM Shark (First results).
