Chilenia was an ancient microcontinent or terrane whose history affected many of the older rocks of central Chile and western Argentina. It was once separated by oceanic crust from the Cuyania terrane to which it accreted at ~420-390 Ma when Cuyania was already amalgamated with Gondwana.
See also 
- ^  Rapalini, A.E. 2005. The accretionary history of southern South America from the latest Proterozoic to the Late Palaeozoic: some palaeomagnetic constraints. From: Vaughan, A. R M., Leat, P. T. & Pankhurst, R. J. (eds). Terrane Processes at the Margins of Gondwana. Geological Society, London, Special Publications, 246, 305-328.