Chaitenia is a distinct fragment of Earth's crust in southern Chile. Rocks of Chaitenia represents an ancient

island arc Island arcs are long archipelago, chains of active volcanoes with intense earthquake, seismic activity found along convergent boundary, convergent plate tectonics, tectonic plate boundaries. Most island arcs originate on oceanic crust and have re ...

that existed next to

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

which became eventually accreted to it. The accretion of Chaitenia to Patagonia occurred in the Devonian period (c. 400–360

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

) as inferred from an event where rocks were put under pressure, deformed and heated dated to that period. After merging into Patagonia,

accretionary complex An accretionary wedge or accretionary prism forms from sediments Accretion (geology), accreted onto the non-Subduction, subducting tectonic plate at a Convergent boundary, convergent plate boundary. Most of the material in the accretionary wedge ...

es developed west of it, meaning Chaitenia constituted a backstop. Chaitenia is not thought to extend beyond the Huincul lineament to the north, beyond which lies the Chilenia terrane.

References

category:Geology of Aysén Region Geology of Chubut Province category:Geology of Los Lagos Region category:Geology of Los Ríos Region Geology of Neuquén Province Geology of the Andes Island arcs category:Terranes {{palaeo-geo-stub