Until recently only one meteorite impact crater was known in Norway, namely the Gardnos crater in Hallingdal north west of Oslo. However it is know widely accepted that a second large crater exists: the Ritland crater. The crater is 2.5km in diameter and about 300m deep. It is most likely made by a meteorite of 100m diameter that impacted about 600million years ago. The crater was discovered by Norwegian geologistFridtjof Riis of the International Research Institute of Stavanger AS. For more information here.