Fastnet, Celtic Sea and St George's Channel

摘要

This offshore area broadly comprises two ENE-trending Mesozoic and Tertiary grabens.udThe northern graben comprises the Fastnet, North Celtic Sea and St. George’s Channeludbasins, separated from the South Celtic Sea and Bristol Channel basins by theudPembrokeshire Ridge–Labadie Bank (Fig. 17.1). The graben appear to represent theudreactivation of Caledonian structures, e.g. the southern margin of the St. George’sudChannel Basin was controlled by reactivation of the onshore Bala Fault System (Naylorud2001). The North Celtic Sea Basin locally developed in the hanging wall of a low-angleudsoutherly dipping fault, which may represent the reactivation of the Variscan Frontudduring Mesozoic extension (Gibbs 1987). However, traditionally, the Variscan Front hasudbeen taken as a poorly lineated feature extending across southern Ireland, north of theudMunster Basin.