Heavy-mineral provinces in southern Skagerrak and northern Kattegat

Abstract

Detailed heavy-mineral studies of the bottom sediment in the Skagerrak-Kattegat area have not been previously reorted. The heavy-mineral suite in the very- fine-sand fraction (63-125um) is dominated (70-91%) by amphibole, epidote and garnet. Based upon mineralogical variations, six distinct provinces have been defined and statistically tested. The distribution patterns of heavy minerals allow preliminary interpretations of the transport pathways and the associated sediment sources. One main source is the mineralogically immature. Quaternary deposits of Scandinavian origin which reflect bedrock composition and show a notably high amphibole content. A second important source in the mature, primarily Tertiary sediments exposed in the southern North Sea and in north- western Europe. Abundant garnet is characteristic of this source. The distinct mineralogical compositions within all provinces indicate that the sediment transport between the provinces does not occur without considerable modificati- on by hydraulic sorting and mixing of sources. The intra- and inter-province relationships between mineralogy and texture are a necessary basis for quantitative evaluations.