Mølen

Part of one of the largest natural monuments from the last ice age.

The Force of the Ice

20.000 years ago, Scandinavia was covered by ice. The kilometer thick ice gradually melted, and after several thousand years, the edge of the glacier stood quite some distance into today's mainland Vestfold and Telemark. The weight of the ice had pushed the landmasses down, so in front of the glacier was the ocean. 13.000 years ago it got colder, and the ice started growing again. The new glacier stopped where the Beech forest, Mølen and Jomfruland is today. Here, the ice stood still for hundreds of years, and on the seabed in front of the glacier, a large moraine of sand, rocks, gravel and clay was deposited. The ice transported rocks while travelling across Telemark, Buskerud and Vetfold county, and glacial rivers brought pebbles, sand and clay. 11.700 years ago, the last ice age finally ended, the ice melted and retreated inwards, until it disappeared.

The Land Rises

The Ra Moraine no longer lies on the sea bed here at Mølen. With the weight of the ice gone, the land rose again. The top of the moraine appeared in the sea and the waves crashed towards the new shoreline. Rocks collided, and were rounded and crushed. Sand and clay was moved, and sorted by waves and the wind. The result is the beautiful rolling stone beach at Mølen and the sandy soil of Brunlanes. You can also see clear terasses in the stones at Mølen. These are earlier shorelines and shows how the land has risen and the violent storm periods of the last 10.000 years.

Mølen and the Ra Moraine includes rocks from many geological periods and origins, the the glacier transported here from large parts of Southern Norway. Among the rolling stones there are many different types of rock, but remember that the entire stone beach is protected, so leave the rocks where they are!

Some of the rocks are typical for certain areas, so visit the Geopark exhibit at Mølen and learn where some of the rocks have been picked up by the glacier!

Larvikite, Syenite and Rhombporfyry - and other rarities

Larvikite, that can be found in the mountains north of Mølen, is not very surprisingly the most common rolling stone at Mølen. However, you can also find many other Vestfold-rocks, like Rhombporfyry and different Syenites. The most exotic rock is flint, which has been brought over from Denmark frozed in ice bergs, drifting along the glacial wall. The ice bergs melted and the flint fell down, mixing with the rolling stones. Even though Larvikite and Rhomporfyry is common here at Mølen, they are rarities on a global level! Read more about our national rock Larvikite here!

Solid mountain in Saltstein

East in Mølen, the rolling stone beach goes over into solid mountain. These are basalts, formed by 300 million year old lava streams. Where the volcano that produced these streams was located is unknown. There were many different lava streams with different ages, but the Brunlanes basalts are most likely the oldest in a large rift zone called the Oslo Rift. This area stretches from Langesund in the south to the Mjøs area in the North. It makes up some of the most spectacular geology in Norway.

At Saltstein, we can see different lava streams mixed with layers of volcanic ash. Some places the basalt is cut through by ores of another rock, Rhombporfyry. This rock is a bit younger, and is evidence of another type of volcano than Cone Volcanoes, was providing the Oslo Rift with its basalt magma. The Rhombporfyry is most likely created y large rift volcanoes.

Guidelines to follow when you visit Mølen:

• The entire area with rolling stones and mounds is protected area.

• It is illegal to pick rocks from the area.

• It is forbidden to move rocks in the mounds, both small and large.

• It is forbidden to build new mounds or pits out of rocks.

• Making fire is not allowed, and single use grills is advised against.

• Be considerate, keep your dog on leash and don't use drones while other people are in the area.