Några Problem Rörande Bottentopografin VID Södra Öland

Abstract

In the very flat sea floor outside the southern part of the Island of Öland in the Baltic some ridge-like features have been observed by means of aerial photographs. The details have been further analysed by the use of echo sounding diagrams and sounding maps and under comparison with the morphology of the steppe-like land surface of the island. Especially there is a long low ridge seen in the slowly dipping sea floor (lime stone) at the southernmost part of the island. It seems to be of the same kind as low ridges observed in some places on the uncovered lime-stone surface (the Alvar area) of the island. The origin of formation is being discussed by geomorphologists and geologists. Ridges of another type make up a distinct lineation in the sea floor. In the littoral zone they disappear and are not to be found above the present sea level. The lineation reveals a pattern of elongated accumulations of loose material. The pattern is interpreted as a kind of glacial flutings from the last glaciation (cf. drumlins, fluted moraine). That the lineation occurs only in the submarine area is due to the fact that the ridges are strongly eroded and levelled at the passage through the surf zone during the postglacial upheaval of the land surface.