The Tornquist Sea between Avalonia and Baltica probably formed at the same time (c. 600 Ma) as the Iapetus Ocean. Gondwana, including Avalonia until Early Ordovician, was separate from Baltica throughout the Cambrian. It probably closed during the Late Ordovician at the time of the Shelveian Orogeny of western England, and consistent with paleobiogeographic data and paleomagnetic apparent polar wander paths for Eastern Avalonia and Baltica.
The suture resulting from closure of the Tornquist Sea may be seen in eastern England and the Lake District as an arc of igneous rocks belonging to the Ordovician. The volcanic series in eastern England, the Ardennes and the Northern Phyllite Belt originated between the Tornquist Sea and the Rheic Ocean during the Ordovician and Silurian.
- Orogenic processes: quantification and modelling in the Variscan Belt by Wolfgang Franke et al., Geological Society of London