Holocene deposits in the northern North Sea: evidence for dynamic control of their mineral and chemical composition? A comment

Abstract

When studying superficial sediment samples of the North Sea, one should discriminate between areas with different oceanographic and sedimentary history. The demonstrated relationships between the chemical compositions and the grain-size distributions of the samples are not the same for the distinguished deposits. The variations are therefore not the result of one single hydrodynamic regime acting throughout the North Sea, but point to differences in source material. In the north-central North Sea the grain-size distributions, and consequently also the associated chemical parameters, reflect the succession from Weichselian arctic to Holocene temperate marine conditions. The abundance of planktonic Foraminifera is also due to the postglacial evolution. The ratios of illite to smectite suggest a change in source area of the clays.