Caledonian orogeny Caledonian orogeny The Caledonian orogeny was a mountain-building era recorded in the northern parts of Ireland and Britain, 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 is 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
Rangitata Orogeny This collision lasted for 50 million years. However, the wet sediments could not just keep piling up. After 50 million years, there was simply too much rock and a 'log jam' in the process was formed. The rocks were squeezed together as they broke and crumpled up. As the compression intensified, the strata were slowly pushed up, creating new land. The collision was also causing a great thickening of the crust, pushing the rocks down into the top of the mantle. The high pressures and temperatures of this occurrence metamorphosed the lower rocks into the Haast Schists. Rangitata Orogeny The