Istider

The smooth rock outcrops, sand and gravel deposits, the course of the Lågen river, and the clays in the valleys are all remnants of the great glacier’s activity and retreat. Most notably, the Ra, the large terminal moraine that encircles all of Scandinavia, stands as a visible monument from the last Ice Age in our region.

About 2.6 million years ago, the great ice ages began. This triggered a dramatic climate deterioration, and glaciers more or less covered Norway during as many as 40 ice ages, alternating with warmer interglacial periods.

The Ra, along with Jomfruland and Mølen, is the result of a colder period after the glacier had started to retreat.

Around 12,800 years ago, the climate turned colder, the glacier advanced, and then remained relatively stationary for about 300 years, from 12,650 to 12,350 years ago. Because of the weight of the ice, the land was pressed down, and seawater stood in front of the glacier. The ice rested on the sea floor, and in the ice sea, large icebergs calved off. Stones, sand, gravel, and clay were pushed up in front of the glacier, carried by the glacier and by meltwater beneath it. As the climate warmed again, the ice cap melted back, leaving behind the large ridge of loose material. As the weight of the ice disappeared, the land rose-quickly at first, then more slowly-a movement that continues today. The long ridge eventually reached sea level, and the materials were sorted by the waves. The result is the beautiful pebble beaches we find at Jomfruland and Mølen