Tubul Formation

Tubul Formation (Spanish: Formación Tubul) is an Early Pleistocene (formerly described as Middle Pliocene in 1968 and Late Pliocene in 1976)[1] 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).[2]

Tubul Formation Stratigraphic range: Early Pleistocene
Type	Geological formation
Underlies	Quaternary sediments
Overlies	Ranquil Formation
Thickness	>100 m (330 ft)
Lithology
Primary	Clay-rich sandstone and silt
Location
Coordinates	37.8°S 73.3°W / -37.8; -73.3
Approximate paleocoordinates	37.9°S 72.8°W / -37.9; -72.8
Region	Bío Bío Region
Country	Chile
Type section
Named for	Caleta Tubul
Named by	Egidio Feruglio
Year defined	1949
Tubul Formation (Chile)

Mollusc fossils found in the formation derives from soft-bed environments (contrary to rocky coasts). Evidence from the fossil mollusc fauna of the Tubul Formation seem to indicate that local water temperatures were lower in the Pliocene than today. Waters and mollusc faunas of Magallanes Region are modern-day equivalents of Tubul Formation.[3]

The formation was first defined by Egidio Feruglio in 1949.[3]