The north-western margin of the Iapetus Ocean

Summary A review of the stratigraphy, sedimentology, petrography, and structure of the Ordovician and Silurian rocks of the Southern Uplands (Scotland) and the Longford-Down zone (Ireland) identifies many features which are typical of accretionary wedges developed at Mesozoic-Recent subduction zones. The bedding becomes gradually more inverted in the west and northwest parts of the Longford-Down zone. Slumping becomes increasingly important along strike southwestwards from Scotland to Ireland. The roles of transform movement along the continental margin and of back arc spreading are also considered.