Pampean orogeny

The Pampean orogen contains a magmatic belt[C] including granodiorites, 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.

[6] The eastern magmatic belt of the Pampean orogeny is interpreted as the remains of a volcanic arc associated with an east-dipping subduction zone while the western one is thought to represent a younger volcanic arc that developed on what was once the accretionary prism of the orogen.

[2] There have been differing views among geologists on the tectonic and paleogeographic position of the Puncoviscana Basin in relation to the events of the Pampean orogeny.

The Pampean orogeny is believed by some geologists to be associated with the accretion of a "Pampia Terrane" to the Río de la Plata Craton, resulting from the closure of a sea that existed in-between.

Paleogeographic reconstruction of Gondwana (in yellow) and Laurentia 550 million years ago during the time of the Pampean orogeny. The Pampean orogeny took place near the right border of the area marked as " Río Plata ". Terranes and microcontinents such as Cuyania , Pampia and Chilenia are omitted.