Two sediment cores from the Norwegian Continental Shelf between Haltenbanken and Frøyabanken (64°06`N, 7°39`E)

Abstract

Two sediment cores, 1.5 and 4.5 m long, were obtained on the continental shelf west of the coast of Trøndelag, W. Norway, from a depression 320 m deep, and in an area with very thin cover of quaternary deposits. The upper part of the cores consists of stratified silt and clay with mainly Postglacial fossil assemblage, a grading with increased clay content downwards, and a clay mineral contents of 10-20% kaolin, 50% illite, 0-10% chlorite and 10-20% mixed layer minerals of different kind. The lower part of the cores is different from the upper part in its more uniforme grain size distribution, its content of poorly consolidated sedimentary rock-fragments in a finer matrix, and in a higher content of organic matter. The fossil assemblage of the rock-fragments, as well as of the matrix, indicates material of Jurassic, Cretaceous and Lower Tertiary age. Furthermore the clay mineral composition is different, with approximately 30-40% kaolin, 1-20% illite, 0-5% chlorite and 30-40% montmorillonite. The lower part of the cores is believed to represent till, consisting mainly of short-transported rock debris from the underlying bedrocks.