Glacial flutings in northern Finnish Lapland

Abstract

The fluting forms in the study area are of two types: (1) mainly deposi­tional moraine ridges, and (2) purely erosional grooves. Both are generally at least a kilometre in length and extend several metres in a vertical direction. The ridges, which are usually to be found on relatively level ground, generally occur in groups. The erosional grooves are concentrated in the bedrock surfaces of the fjell summits. The flutings are usually oriented in the direction of the regional ice movement, S‑SW ‑> N‑NE. Fabric analysis provided indications of movements in the basal ice con­verging upon the crest of the ridge. These are interpreted as being due principally to local variations in ice pressure conditions on formation of the flutings. While the bedrock grooves began to form well before the end of the glaciation phase, the fluting ridges developed during deglaciation, the oldest of the ridges being large in size and orientated in parallel with the drumlins in the area, and the youngest small and with an orientation which shows the influence of local topography on the movements of the rather thinner ice cover.