Near the village Alvdal you can find the river Sølna. This place is full of interesting geological features and it is possible to show many different processes. At the given coordinates you will find a steep canyon. So it would also be possible to inform you about the developement of this geologic feature. But with this earth cache the focus will be on the kettle basins. Kettle basins are a result of the last ice age. In the past, the theory for the development of a kettle basin was the following.
A big stone, a so-called erratic block was transported down the glacier with melting water. This block should have carved the rock with its rotation. But today we know that this theory failed. Here the actual theory. Melting water drained through the crevasses to the bottom of the glacier. The melting water accumulated into streams with enormous power. Sometimes there were turbulence in the water and that is the origin for the development of kettle basins. Within these turbulence in the water were high pressures and velocity. The speed could be up to 200 km/h. The cause for the erosion of the rock is the sand and the gravel in the water.
These parts carved the kettle basins. At this place you can see the round forms of the kettle basins nearly everywhere. The Sølna canyon is not so famous as the kettle basins of Helvete in the Espedal valley. The carvings there are much bigger but I think this place is not so crowded and the nature here is pretty impressive.
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1) There is a small bridge over the Sølna river. Here you have a good view into the canyon. With logic conclusion, what do you learn here about the draining direction of the melting water?
2) What is an ice shed and which direction was the regional ice shed?