The Irish Variscides: problems, perspectives and some solutions

Abstract

ABSTRACTA review is presented of interpretations made to date of the Irish Variscides, and the various models of Late Palaeozoic crustal evolution. An examination is then made of the factors controlling Variscan strain in Ireland, including lithological competence, basement fabric and basement‐cover thickness. From this, the difficulties of recognizing Variscan ‘fronts’ and ‘fold belts’ are emphasized.In order to determine whether all putative Variscan strain is indeed Variscan. in age, new time‐temperature data (vitrinite reflectance; apatite fission track populations) are discussed, along with offshore data. A case is then presented for recognizing quite distinct episodes of both Variscan and post‐Variscan heating and deformation. Some of the implications for the Variscides to the east are briefly examined, and the suitability of a regional ‘escape tectonics’ model is tested.