Abanico Formation

Abanico Formation Stratigraphic range: Eocene–Miocene
Type	Geological formation
Underlies	Farellones Formation
Thickness	ca. 3,000 m (9,800 ft)
Location
Region	O'Higgins Region, Santiago Metropolitan Region, Valparaíso Region
Country	Chile

Abanico Formation (Spanish: Formación Abanico) is a 3 kilometres (9,800 ft) thick sedimentary formation exposed in the Andes of Central Chile. The formation has been deposited in a timespan from the Eocene to the Miocene. Abanico Formation's contact with the overlying Miocene Farellones Formation has been the subject of differing interpretations since the 1960s.

The sediments accumulated in the Abanico Extensional Basin within a context of the Andean orogeny. The basin had a north-south elongated shape that spanned the latitudes of 29–38° S. Tectonic inversion from 21 to 16 million years ago made the basin collapse and the sediments to be incorporated to the Andean ranges. The northern part of the basin inverted before the southern part. Parts of the formation are known to have experienced Prehnite-pumpellyite facies metamorphism.

The Tinguiririca fauna is known from the fossils found in the Abanico Formation near the Tinguiririca River.

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