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When the Scandinavian inland ice left the Erken basin about 10000 years ago the moraine (till) was covered by more than 100 metres of water. Sedimentation started, at first mainly of clay, and has continued up to the present day. Continual land upheaval has decreased the depth of the water and altered the character of the sedimentation. A core was taken through the sediments down to the moraine at a depth of 11 metres. Analyses of total N and easily soluble Ca, K and Na were carried out on samples from the core. The concentration of N should give a good indication of the organic sedimentation which becomes larger at higher levels in the core. This is particularly noticeable in the sediment deposited during the recent 2000 years, after the Erken basin became isolated from, the Baltic and turned into a fresh water lake. The sediment mainly consists of soap clay with a varying gyttja content. The mobility of water and salts in these clays is very restricted and especially, as in the case here, when ...