Chilenia

Chilenia refers to a hypothesized microcontinent that collided with the western margin of South America during the Paleozoic Era. Geological evidence, primarily found in Chile and Argentina, suggests that Chilenia was a landmass separate from Gondwana that existed during the Cambrian and Ordovician periods.

The accretion of Chilenia is thought to have significantly contributed to the growth of the Andes Mountains and the formation of the Precordillera terrane in western Argentina. Geochemical and paleontological data provide support for the allochthonous nature of the Precordillera, indicating its origin as part of Chilenia rather than indigenous to the South American plate.

The paleogeographic origin of Chilenia is still debated, but some researchers suggest a Laurentian (North American) affinity based on fossil similarities. The timing of the collision is generally placed during the late Ordovician or early Silurian periods. After its accretion, Chilenia became a permanent part of South America, contributing to its geological complexity and diversity. Subsequent Andean orogenies further deformed and modified the Chilenia terrane.