Trolldalen, Naturreservat

In the Trolldalen and Vargkitteln nature reserves, a mighty ice river flowed when the ice sheet melted 10 000 years ago. The water sanded the edges of the valley sides and shaped the rock. Today, the steep valley sides are covered in old-growth forest with many rare mosses, lichens and fungi. Be careful on your hike, as wet conditions as well as snow and ice make stones, rocks and roots slippery!

The ice river shaped the valley

The Trolldalen and Vargkitteln nature reserves are parts of the same rift valley, Östra Trolldalen. The crevasses were already formed when Kilsbergen was formed several million years ago. But it was not until the last ice age, around 10,000 years ago, that Östra Trolldalen took on its dramatic and distinctive shape. As the ice sheet began to melt, a large lake formed in Kilsbergen. The water continued towards the sea through the valley, where the rushing water masses ground rocks and boulders on their way. Some of the rocks that the mighty ice river washed through Östra Trolldalen ended up on a former seashore that is now part of the Lövbrickan nature reserve. The fine-grained material, sand and clay, was carried further out to sea and settled on the seabed that would later become the fertile Närkeslätten.

Giant pots

The so-called giant pots are the most peculiar traces of the meltwater's progress in Östra Trolldalen. According to older theories, it was a so-called runner stone that, with the help of the water currents, dug out these pots of stone. Today, geologists point to another main cause, a process called cavitation. The flowing water was affected by high pressure from the ice. At a rocky outcrop or other obstacle, the velocity of the water stream increased, only to decrease abruptly after the obstacle. The bubbles in the water, formed by gases, dissolved when the speed of the water current suddenly decreased. The force generated by the dissolving bubbles was like a hammer digging into the rock. Rocks and gravel in the rushing water have since helped to hollow out and polish the pots. One of the area's most famous and legendary giant cauldrons is called Trollgrytan and is located in Trolldalen Nature Reserve.

Paradise for mosses and fungi

In Trolldalen Nature Reserve, the rift valley is narrow. Trolldalen is known for the exciting ice formations that form in the gorge in winter. The valley sides are covered by an ancient spruce forest that is almost unaffected by forestry. The forest is damp, shady and full of dead trees - a perfect environment for many unusual mosses, lichens and fungi. The rare fungus woolly adelgid grows on lying, dead tree trunks. The wood stair moss and the wood bag moss are two unusual mosses that also thrive on decaying spruce logs.

Sign-interpreted information