It was the only orogeny in Laurentia at that time which resulted in deformation, folding and metamorphism.
The Fleur de Lys rocks in Newfoundland may have been affected by the Grampian orogeny as well.
[1] In the Cambrian and early Ordovician, shallow water carbonates and deep water turbidite basins, which formed the Southern Highland Group, dominated the section of the Laurentian coast that would be later separate to form Scotland.
Some proposals in 1983 and 1984 suggested that the arc is buried under younger sediments in Scotland's Midland Valley.
During the collision at the edge of the Laurentian continent, an ophiolite nappe was overthrusted, possibly preserved in Unst, in the Shetland Islands.