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www.ocean-sci.net/8/11/2012/
doi:10.5194/os-8-11-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Mapping turbidity layers using seismic oceanography methods
1Department of Earth Sciences, Durham University, Durham, DH1 3LE, UK
2School of Marine Science and Engineering, Plymouth University, Plymouth PL4 8AA, UK
*now at: Geospatial Research Ltd, Durham University, Durham DH1 3LE, UK
Abstract. Using a combination of seismic oceanographic and physical oceanographic data acquired across the Faroe-Shetland Channel we present evidence of a turbidity layer that transports suspended sediment along the western boundary of the Channel. We focus on reflections observed on seismic data close to the sea-bed on the Faroese side of the Channel below 900 m. Forward modelling based on independent physical oceanographic data show that thermohaline structure does not explain these near sea-bed reflections but they are consistent with optical backscatter data, dry matter concentrations from water samples and from seabed sediment traps. Hence we conclude that an impedance contrast in water column caused by turbidity layers is strong enough to be seen in seismic sections and this provides a new way to visualise this type of current and its lateral structure. By inverting the seismic data we estimate a sediment concentration in the turbidity layers, present at the time of the survey, of 45 ± 25 mg l−1. We believe this is the first direct observation of a turbidity current using Seismic Oceanography.
Final Revised Paper (PDF, 4331 KB) Discussion Paper (OSD)
Citation: Vsemirnova, E. A., Hobbs, R. W., and Hosegood, P.: Mapping turbidity layers using seismic oceanography methods, Ocean Sci., 8, 11-18, doi:10.5194/os-8-11-2012, 2012. Bibtex EndNote Reference Manager XML
