Vejle Fjord Formationen ved Brejning. Sedimenterne og foraminiferfaunaen (oligocæn - miocæn)

Abstract

This report deals with the sediments and the microfauna of the Tertiary sequence in the cliff at Brejning on the east coast of Jutland, Denmark. The section includes fossiliferous, marine clays and silts with a makrofauna of molluscs, for which reason these particular deposits were previously referred to the Oligocene. The beds on top of the proved Oligocene layers consist of clays, sands and silts which also in part are marine.

The cliff section was surveyed by the authors, and a shallow boring was carried out on the beach below the cliff in order to study the transition at the unconformity between the middle Oligocene fossiliferous beds and the underlying Søvind marl.

In part I of the paper the results of the petrological investigations carried out by the first author are found. A description of physical properties of the sediments opens the chapter, and the mineral content of 62 samples collected in the exposure and from the boring is reported. The main results of the latter study are shown in the diagram plate I.

It is concluded that Fennoscandia was the source area of the sediments which suggest marine, partly lagoonal environments around Brejning during deposition.

The sequence is finally compared with other late-Tertiary deposits in Slesvig, Holstein and Holland.

The microfauna, which is treated by the second author in part II, consists of 63 species of foraminifera. It is described in more or less detail, the genera Angulogerina and "Rotalia" having been the subject of a special study.

The frequencies of species have been determined in all samples examined, and the biostratigraphic and paleoecologic significance of the microfauna is discussed on the basis of the results. The fossiliferous part of the Tertiary sequence is ultimately subdivided into four faunizones as shown on plate II.