Great Glen Fault

Aligned northeast to southwest, the Great Glen Fault extends further southwest in a straight line through Loch Linnhe and the Firth of Lorne, and then on into northwestern Ireland, directly through Lough Swilly, Donegal Bay and Clew Bay as the Leannan Fault.

The exact timing is uncertain, but associated folds within the Devonian are cut by members of the Late Carboniferous to Early Permian dyke swarm.

The Great Glen Fault had its final phase of movement during the Late Cretaceous to Early Tertiary.

There is not agreement about whether the Great Glen Fault is "active" – accumulating seismic slip.

[4] Some parts of the fault are moving in opposite directions, but the extent of displacement is not agreed on.

Map of the Great Glen Fault and other late Caledonian strike-slip faults in Scotland and northwestern Ireland
Metamorphic zones , and Moine Thrust Belt , Great Glen Fault and Highland Boundary Fault
Euramerica in the Devonian (416 to 359 Ma) with Baltica , Avalonia (Cabot Fault, Newfoundland and Great Glen Fault, Scotland) and Laurentia