European accretion in the Palaeozoic: recognition and origins of accreted terranes (lecture)

Dr John Winchester, Keele University

The Palaeozoic growth of Europe was dominantly by accretion of terranes, derived from the Americas and Africa, which became attached to its southwest margin. These came in four stages: (1) Cambrian relocation of displaced blocks from southeast Baltica; (2) End-Ordovician accretion of Avalonia, formerly adjacent to Amazonia; (3) Silurian collision with Laurentia, of which a fragment (including Scotland) remained attached to Europe after the Palaeogene Atlantic opening; (4) Carboniferous accretion of Variscide blocks (Armorican Terrane Assemblage), originally adjacent to North Africa, extending from Iberia to Turkey. Their basement rocks provide evidence of their origins and the geological reasons for their migration.