The Avalon Spur; Former Southern Margin of the Iapetus Ocean and Northern Border of the Theic Ocean

Abstract

During the Lower Palaeozoic, the Avalon Spur made up the southern margin of the Iapetus Ocean. Taking into account the limits of the Gander Zone defined in the previous chapter, it can be seen that the northern margin of this spur includes parts of New Brunswick, the Avalon Peninsula of Newfoundland, the S.E. fringe of Eire and most of Wales. Towards the South, the Avalon Spur was bordered by the Theic Ocean. The best criterion for defining the southern limit of the Spur is given by the sudden and systematic interruption of N-S trending structures in the Avalonian basement which abutt against a continuous belt of basic bodies. Avalonian basement terrains are also to be found in northern Nova Scotia as well as the Iberian and Armorican massifs of Western Europe.