Loreto Formation

Loreto Formation (Spanish: Formación Loreto) is a sedimentary formation of Late Eocene age in the southernmost Magallanes Basin. It overlies the Leña Dura Formation and the contact with an overlying formation is not observed.^[1] From 2013 to 2020 its coals were mined in Invierno mine, Riesco Island.^[2][3][4]

Loreto Formation
Stratigraphic range: Priabonian (Divisaderan)
Type	Geological formation
Underlies	not observed
Overlies	Leña Dura Formation
Lithology
Primary	Sandstone
Other	Conglomerate, coal
Location
Coordinates	53.1°S 71.1°W / -53.1; -71.1
Approximate paleocoordinates	55.3°S 61.4°W / -55.3; -61.4
Region	Magallanes y la Antártica Chilena Region
Country	Chile
Extent	Magallanes Basin
Type section
Named by	Hoffstetter et al.
Year defined	1957
Loreto Formation (Chile)

Description

The formation contains fossil wood, leaf imprints and palynomorphs.^[5] Also fossil fish of Striatolamia macrota and Ischyodus dolloi and indeterminate Spheniscidae fossils have been found in the formation.^[6][7]

The formation crops out in Brunswick Peninsula and Sierra Baguales among other places.^[8]