The Sgurr Beag Thrust is an important tectonic structure within the Neoproterozoic metasedimentary rock sequences of the Scottish Highlands.
The history of this structure remains poorly understood although it is thought to be at least partly of Caledonian age.
[1] It is currently interpreted to extend from the Morvern peninsula in the southwest (with a possible extension onto the Isle of Mull), to the Dornoch Firth where it disappears beneath the Old Red Sandstone.
It is often marked by the presence of inliers of Lewisian basement, which are found in its hanging-wall (structurally above the fault plane).
The age of peak metamorphism within the rocks above the thrust is dated to 840–720 Ma, the timing of the Knoydartian event(s).