Rote Tone im Rhät-Lias Schonens

Abstract

This paper is concerned with the discovery of red beds in the coal-bearing Rhaetic-Liassie strata at Östraby and Skromberga in northwestern Scania. Red clays at Östraby earlier were considered as Keuper (Kågeröd) in age, the interpretation of the structure being a dome-shaped elevation with varicolored older sediments in the core of the uplift. Palacontologic evidence supported this view, as fossils suggestive of a Rhaetic age were found immediately above the red clays. Contrary to this assumption, gravimetric explorations and exploratory drilling carried out during recent years have revealed, that Östraby is structurally a depressed area, surfaced by younger deposits of the Rhaetic-Liassic strata. The chemical properties of the red Östraby clays as compared with red Kågeröd clays are described. The contradiction in the occurrence of red beds in a coal-bearing sedimentary environment is examined on the background of an analogous modern occurrence in Brazil, where red colors of sediments under reducing conditions were preserved because of rapid burial. A study of the palaeoclimatie and palaeogeographic factors and of the tectonical framework of the Rhaetic-Liassic sedimentation in Seania affords evidence, that the red clays described are the sedimentary response to tectonism, indicative of tectonic activity contemporaneous with deposition.