Highland Boundary Fault

The Highland Boundary Fault is a major fault zone that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two different geological terranes which give rise to two distinct physiographic terrains: the Highlands and the Lowlands, and in most places it is recognisable as a change in topography. Where rivers cross the fault, they often pass through gorges, and the associated waterfalls can be a barrier to salmon migration.

The fault is believed to have formed in conjunction with the Strathmore syncline to the south-east during the Acadian orogeny in a transpressive regime that caused the uplift of the Grampian block and a small sinistral movement on the Highland Boundary Fault.