Tubul Formation

Tubul Formation Stratigraphic range: Pliocene
Type	Geological formation
Underlies	Quaternary sediments
Overlies	Ranquil Formation
Thickness	more than 100 m (330 ft)
Lithology
Primary	Clay-rich sandstone and silt
Location
Region	Bío Bío Region
Country	Chile
Type section
Named for	Caleta Tubul
Named by	Egidio Feruglio, 1949

Tubul Formation (Spanish: Formación Tubul) is a Pliocene sedimentary formation located in Arauco Province in south–central Chile. Its sediments were deposited in marine conditions. It overlies unconformably the folded sedimentary formations of Ranquil (Miocene–Pliocene), Quiriquina (Late Cretaceous) and the Lebu Group (Paleocene-Eocene).

Mollusc fossils found in the formation derives from soft-bed environments (contrary to rocky coasts). Evidence from the fossil mollusc fauna of Tubul Formation seem to indicate that local water temperatres were lower in the Pliocene than today. Waters and mollusc faunas of Magallanes Region are modern-day equivalents of Tubul Formation.

The formation was first defined by Egidio Feruglio in 1949.

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