Reconstructing North Sea palaeolandscapes from 3D and high-density 2D seismic data: An overview

Abstract

The North Sea subsurface shows the marks of long-term tectonic subsidence. Much of it contains a thick record of glacial and interglacial deposits and landscapes, formed during multiple glacial cycles and the associated regressions and transgressions during the past two million years. At times of lower sea level than today, areas that are presently submerged were fertile lowlands more favourable for hunting and gathering than the surrounding upland. These drowned lowlands are not captured by traditional 1:250,000 geological maps of the North Sea subsurface because the underlying seismic and core data are commonly too widely spaced to achieve this. Palaeolandscape mapping requires identification of building blocks with spatial scales in the order of 1 km or less. As high-density 2D and high-quality 3D seismics are becoming available for an increasing part of the North Sea, glacial and interglacial palaeolandscapes can be reconstructed for more and more areas. An overview of published palaeolandscape reconstructions shows that shallow time slices through 3D data provide map views that are very suitable for the identification of landscape elements. For optimal results, each time slice needs to be validated and ground-truthed with 2D seismics and with descriptions and analyses of cores and borehole samples. Interpretations should be made by teams of geoscientists with a sufficiently broad range of expertise to recognise and classify even subtle or unfamiliar patterns and features. The resulting reconstructions will provide a context and an environmental setting for Palaeolithic, Mesolithic, and Neolithic societies and finds.