Great Glen Fault

The Great Glen Fault is a strike-slip fault running northeast to southwest through Scotland's Great Glen, continuing through Loch Linnhe and the Firth of Lorne into northwestern Ireland as the Leannan Fault and, on the far side of the Atlantic, as the Cabot Fault through Newfoundland, a combined trace of at least 300 miles. It formed during the Caledonian orogeny, as the Laurentia and Baltica plates collided around the Silurian-Devonian boundary roughly 430 to 390 million years ago, and has since accumulated an estimated 64 miles of total displacement through several distinct phases of movement: sinistral slip in the Devonian, dextral slip in the Carboniferous, and further activity from the Late Cretaceous into the Early Tertiary. Quaternary glacial erosion along its weakened rock carved out Loch Ness, and occasional moderate tremors recorded over the past 150 years keep geologists divided over whether the fault remains actively accumulating strain today or is simply a reactivated structure within otherwise stable continental crust. This entity documents the Great Glen Fault specifically as a geological formation.