Erratic boulder in Väätäjänniemi

The slowly moving ice sheet eroded the underlying rock forming rounded outcrops called roches moutonnées and their striations. The rock material detached from bedrock were deposited on the bottom and at the edge of the ice sheet into moraine landforms. The ice sheet also transported huge rocks called erratic boulders. The Väätäjänniemi erratic boulder in Vaala is about the size of a small detached house and weights several hundred thousand kilos. The erratic boulder consists of pegmatite granite crystallised deep under the ancient mountain range.