Integration of geospatial data for mapping variation of sediment thickness in the North Sea

Abstract

The study presents geospatial analysis of the seabed distribution of North Sea sediments. Data include thematic datasets with a high-resolution: GlobSed 5-arc-minute total sediment thickness grid combined with GEBCO regional bathymetric grid and geophysical grids showing EGM2008 geoid undulations and marine free-air gravity. The data have been processed using GMT. The data analysis revealed variations in the occurrence and distribution of sediment materials as well as its relationship with topography and regional geophysical settings, marine free-air gravity and geoid. Analysis of the topographic map was performed to describe the structural features of the seafloor. Ridges, large-scale sandbanks, shallow coastal areas and local depressions illustrate uneven bathymetry with northward increasing depths. The highest recorded value is 12,779.642 m located in the northern ares in the SW coast of Norway. Moderate values of sediment thickness (5,000-6,000 m) stretching in NW direction clearly correlate with the marine gravity anomaly isolines with values 10-20 mGal which points at the local relief forms in central basin of the North Sea. The subsidence of the outer shelf of the North Sea and increase of sediment thickness is notable in the central depressions and northern areas: Faroe Islands and Rockall Plateau. The sediment thickness shows the relationship with the topography increasing toward high latitudes. It is also associated with the isostatic sink of the submarine relief in the peripheral areas of the Arctic Ocean. Topographic compensation for the seafloor subsidence by increasing sediment thickness explains local dislocations connected with submarine geomorphology. This study also demonstrated that accurate GMT-based cartographic visualization of the oceanic seafloor using high-resolution multi-source raster grids is crucial to better understand spatial distribution of the marine sediments in the northern latitudes of the North Atlantic Ocean.