The palaeogeographic evolution of Southern Britain during early Palaeozoic times: a reconciliation of palaeomagnetic and biogeographic evidence

Abstract

Palaeomagnetic, biogeographic and palaeoclimatic evidence together suggest that, in the Early Ordovician, Southern Britain lay off the west African margin of Gondwana at around 60° S. The combination of these disciplines reduces latitude uncertainties to around 5 to 10 degrees. Rifting of Avalonia from Gondwana was followed, during most of the Ordovician, by northward drift as Avalonia and Baltica converged with subduction of Tornquist Sea crust. Both continents had similar moderate northward drift rates (3–6 cm/yr). so their convergence probably had a considerable longitudinal component. Silurian and early Devonian data indicate that northward drift of Avalonia and Baltica continued after their collision, and that Southern Britain reached a latitude of around 20° S by c. 400 Ma.