What may have been an episode of mountain building that occurred about 1050–730 Ma ago, prior to the Caledonian orogeny, affecting the Morar area north-west of the Great Glen Fault, in what is now Scotland. Alternatively, the evidence suggesting an orogeny may be explained as a phase of pegmatite formation. If it was a genuine orogeny it may mark the start of the subduction that led to the closing of the Iapetus Ocean.