Search

This research demonstrates the impact that glaciations had on the geomorphology and sediment deposition of the NW Irish continental margin, including both sides of the Rockall Trough and the Rockall Bank. A modern hydrographic, geophysical and sedimentological approach is used to analyse and interpret new and historical datasets, including multi beam, sidescan sonar, seismic and core data. New methodologies such as CUBE and Geocoder algorithms for multi beam bathymetry and backscatter data processing, 3D visualisations, ArcGIS Spatial and Hydrological Analysis and digital X-Ray scanning are used to deliver an accurate geomorphological and sedimentological interpretation and to understand the changes that occurred in the sedimentary processes from shelf edge to basin floor since the last glaciation, through deglaciation and in the Holocene. This research demonstrates a number of correlations between glacial geomorphology observed on the continental shelf and the various geomorphological and sedimentary features observed along the NW Irish continental slope and trough. It also provides extensive evidence that the Rockall Bank was scoured by several generations of icebergs and acted as a natural barrier against which icebergs coming from the western Atlantic Ocean grounded. Near seabed geophysical investigation throughout the Irish Rockall Trough is used to classify the area into six sedimentary provinces, each characterised by different depositional processes. This also provides new evidence of previously undetected mass transport deposits and extensive fluid-migration on a wide area of the trough. Finally, the study of sediment cores along two major canyons and across the trough provides a regional perspective on the sedimentary processes that took place since the last glaciation on the north-eastern margin of the Rockall Trough. The study reveals that margin physiography, distance from the ice sheet grounding zone, style of glaciation on the shelf and strength of deep sea circulation are the main controlling factors over the depositional processes.