A mountain-building episode that occurred about 1800–1600 Ma ago, and which is recorded in north-west trending folds in the Lewisian gneisses of what is now the extreme north-west of Scotland. It is a continuation of the Proterozoic Ketilidian and Nagssugtoqidian orogenies of Greenland, and may be a continuation of the Scourian orogeny which immediately preceded it.