A Wilson cycle (first coined by Dewey and Burke in 1977) describes the sequence of continental rifting, the opening of an ocean basin, the subsequent destruction of an oceanic basin by subduction, and finally ocean closure and continent-continent collision. The Caledonian orogenic cycle is the “original” Wilson cycle as described by J. Tuzo Wilson in 1966. It commenced in the late Proterozoic with the protracted disassembly of the Rodinia supercontinent and the formation of the Iapetus ocean. The closure of the Iapetus began in the early Palaeozoic and the final continent-continent collision between Laurentia and Baltica took place in the Silurian-Devonian, shortly followed by orogenic extension in the Devonian-Carboniferous.

The Caledonian mountain belt represents a world-class example of a deeply denudated Himalayan-style orogen. The exposed crustal sections allow the study of all stages of the Wilson cycle and may contribute to our understanding of many of the fundamental questions in plate tectonics, including (1) the role of inheritances during rifting and collision, (2) continental-rifting, break-up and ocean formation, (3) subduction, (4) marginal basin formation, (5) arc-continent and continental collisions, (6) (U)HP metamorphism, (7) orogenic wedge formation and dynamics, (8) the formation of crustal-scale shear zones, (9) ductile and brittle deformation mechanisms, and (10) the dynamics of late- to post-orogenic extension and deep crustal exhumation.

This session aims to bring together scientists studying rocks and geological processes from all stages of the Caledonian Wilson cycle, i.e. from rifting to collision and post-orogenic extension, and welcomes sedimentological, petrological, geochemical, geochronological, geophysical, structural, and modelling contributions that help to improve our understanding of the Caledonides and mountain belts in general.