Histoire de la dénudation dans le corridor du loch Ness (Écosse) : mouvements verticaux différentiels le long de la Great Glen Fault

Abstract

The Great Glen Fault (GGF) is a major lithospheric strike-slip fault system that cuts across the Caledonian orogenic belt of Scotland. It separates the Northern Highlands terrane from the Grampian terrane. Movement history along the fault extends at least into the Early Palaeozoic. The low-temperature history of the Scottish Highlands covers a significant period from the Late Palaeozoic to the Present, but the magnitude of vertical movements that affected the GGF area during that time is still a matter of debate. Fission track analysis on detailed vertical profiles in the Ballachulish and Strontian complexes, as well as on a profile oriented northeastwards across the GGF, reveals distributed differential vertical movements along the fault during the Late Palaeozoic. The Mesozoic denudation is estimated at a maximum of 2 km before a more recent widespread exhumation event that started at around 40–25 Ma, leading to 1.6 to 2 km of erosion.