Influence of sediment drift accumulation on the passage fop gravity driven sediment flows in the Iceland Basin, NE Atlantic

Elliott, G. and Parson, L.M. (2008) Influence of sediment drift accumulation on the passage fop gravity driven sediment flows in the Iceland Basin, NE Atlantic. Marine and Petroleum Geology, 25 (3), 219-233. (doi:10.1016/j.marpetgeo.2007.07.002).

Abstract

The Maury Channel is a deep-sea sediment transport system located in the Iceland Basin and extends from the Icelandic plateau southwards towards the Charlie-Gibbs Fracture Zone (CGFZ). This study has utilised multibeam bathymetry and multi-channel seismic reflection survey data along 480 km of its 1200 km pathway. In the northern reach of the channel it is predominantly broad (>20 km) and shallow (10 m). Further to the south the channel narrows (5–10 km) and locally deepens to 150 m prior to finally discharging onto the Eriador Plain to the north of the CGFZ. DSDP Site 115 in the Iceland Basin can provide insight into the evolution of the system as it sampled a suite of volcaniclastic turbidites of unequivocal Icelandic provenance. This sequence produces distinct amplitude anomalies on seismic reflection profiles allowing it to be mapped over an area of at least 26,000 km2. The southern edge of the high velocity unit is delimited by onlap onto the flanks of the Miocene (and younger) Gardar Drift. The drift appears to have initially acted as a barrier to southerly flows and promoted ponding of flows in the Maury Fan. Continued sediment supply from Iceland eventually filled the Maury Fan leading to the overspilling of the Gardar Drift dam. A result was the initiation of the Maury Channel. To the south of the drift, where the seabed is steep, flows are confined to the channel, whereas to the north of the drift, where the gradient is less, unconfined flow pathways dominate. The Maury Channel system highlights the interaction between turbidity currents and bottom currents on abyssal plains. The growth of sediment drifts not only mould the seafloor through their bathymetric development but also, through the building of seafloor topography, influence the passage and behaviour of gravity-driven sediment-laden flows along the seafloor.

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