Cadomian Orogeny Cadomian Orogeny The Cadomian Orogeny was a tectonic event or series of events in the late Neoproterozoic, about 650–550 Ma, which probably included the formation of mountains. This occurred on the margin of the Gondwana continent, involving one or more collisions of island arcs and accretion of other material at a subduction zone. The precise events, and geographical position, are uncertain, but are thought to involve the terranes of Avalonia, Armorica and Iberia. Rocks deformed in the orogeny are found in several areas of Europe, including northern France, the English Midlands, southern Germany, Bohemia, southern Poland and the southwest Iberian
Pampean orogeny monzogranites, and volcanic rocks, all of them of calc-alkaline chemistry. The igneous rocks of this belt formed at various times in over the period from 555 to 525 million years ago. From 525 million years ago onward another magmatic belt of peralumineous and mafic rocks developed further amidst gneiss, schist, amphibolites and carbonate rocks. The igneous rocks of this belt formed in the period from 525 to 515 million years ago. The Pampean orogeny can be considered part of the larger Terra Australis orogeny or of the Brasiliano orogeny. The Pampean orogeny developed at a similar time as the Paraguai