Caledonian Orogeny

The Caledonian orogeny is a mountain building era (orogeny) recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490-390 million years ago (Ma). It was caused by the closure of the Iapetus Ocean when the continents and terranes of Laurentia, Baltica and Avalonia collided.

The Caledonian orogeny has been named for Caledonia, the Latin name for Scotland. The name was first used in 1885 by Austrian geologist Eduard Suess for an episode of mountain building in northern Europe that predated the Devonian period. Geologists like Émile Haug and Hans Stille saw the Caledonian orogeny as one of several episodic phases of mountain building that had occurred during the Earth's history. Current understanding has it that the Caledonian orogeny encompasses a number of tectonic phases that can laterally be diachronous. The name "Caledonian" can therefore not be used for an absolute period of geological time, it applies only to a series of tectonically related events.