Dorotea Formation

The Dorotea Formation is a geological formation in the Río de Las Chinas Valley of the Magallanes Basin in Patagonian Chile whose strata date back to the Campanian to Maastrichtian of the Late Cretaceous.^[1]

Dorotea Formation
Stratigraphic range: Late Campanian-Maastrichtian ~72–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Underlies	Man Aike Formation
Overlies	Tres Pasos Formation
Thickness	100–350 m (330–1,150 ft)
Lithology
Primary	Sandstone, claystone
Other	Conglomerate
Location
Coordinates	50.7°S 72.5°W / -50.7; -72.5
Approximate paleocoordinates	52.9°S 60.5°W / -52.9; -60.5
Region	Magallanes Region
Country	Chile
Extent	Río de Las Chinas Valley, Magallanes Basin
Type section
Named for	Sierra Dorotea
Named by	Katz
Year defined	1963
Dorotea Formation (Chile)

Description

The Dorotea Formation was first described by Katz in 1963. The formation comprises sandstones with frequent conglomerate lenses, concretionary levels and claystones. The Dorotea Formation includes calcareous sandstones with abundant marine invertebrate and fragmentary vertebrate fossils. Hervé et al. (2004) obtained a maximum radiometric age of 67.4 ± 1.5 Ma from detrital zircons contained in sandstones of the Dorotea Formation.^[2]

The mudstones and sandstones of the formation were deposited in a fluvial environment. The formation conformably overlies the Tres Pasos Formation and is unconformably overlain by the Lutetian to Bartonian Man Aike Formation.^[3] The thickness of the formation ranges from 100 metres (330 ft) in the Sierra Baguales in the north to 350 metres (1,150 ft) in the eponymous Sierra Dorotea in the south.^[4]

Fossil content

The following fossils were reported from the formation:^[5]

Amphibians

Amphibians of Dorotea Formation
Taxa	Species	Material	Notes	Images
Anura[6]	Indeterminate		A frog

Reptiles

Reptiles of Dorotea Formation
Taxa	Species	Locality	Material	Notes	Images
Aristonectinae[7]	Indeterminate
Aristonectes	A. sp.[7]
Yaminuechelys	cf. Yaminuechelys sp.[6]
Panchelidae[6]	Indeterminate	Saurópodo sector (Section SP-17).	Distal fragment of right humerus and distal end of right femur.
Elasmosauridae	Indeterminate

Dinosaurs

Ornithischians

Ornithischians of Dorotea Formation
Taxa	Species	Locality	Material	Notes	Images
Gonkoken[8]	G. nanoi		Several incomplete specimens belonging to individuals of different ages	A hadrosauroid
Ornithischia[6]	Indeterminate
Stegouros	S. elengassen		CPAP-3165 (holotype), a holotype consists of a relatively complete skeleton with a skull and lower jaws.	A parankylosaur

Saurischians

Saurischians of Dorotea Formation
Taxa	Species	Material	Notes	Images
Enantiornithes[9]	Indeterminate
Megaraptoridae[9]	Indeterminate
Ornithurae[9]	Indeterminate
Sauropoda[6]	Indeterminate
Unenlagiinae[9]	Indeterminate
Theropoda[6][9]	Indeterminate

Mammals

Mammals of Dorotea Formation
Taxa	Species	Locality	Material	Notes	Images
Magallanodon[10]	M. baikashkenke[10]			A gondwanathere
Orretherium	O. tzen[11]			A mesungulatid mammal
Mammalia[6]	Indeterminate

Fish

Fish of Dorotea Formation
Taxa	Species	Material	Notes	Images
Ischyrhiza	I. chilensis[4]
Carcharias	C. sp.[4]
Serratolamna	Indeterminate[4]

Invertebrates

Invertebrates of Dorotea Formation
Taxa	Species	Locality	Material	Notes	Images
Dorotheus	Dorotheus guidensis[12]
Pterotrigonia	P. cazadoriana[2]
Gunnarites	G. sp.[2]
Pachydiscus	P. aff. gollevilensis[2]

See also

• List of dinosaur-bearing rock formations
• Quiriquina Formation
• Allen Formation, Campanian to Maastrichtian fossiliferous formation of the Neuquén Basin
• Angostura Colorada Formation, Campanian to Maastrichtian fossiliferous formation of the North Patagonian Massif
• La Colonia Formation, Campanian to Maastrichtian formation of the Cañadón Asfalto Basin
• Colorado Formation, Campanian to Maastrichtian fossiliferous formation of the Colorado Basin
• Lago Colhué Huapí Formation, Campanian to Maastrichtian fossiliferous formation of the Golfo San Jorge Basin