Cerro Barcino Formation

The Cerro Barcino Formation (also known as the Gorro Frigio Formation) is a geological formation in South America whose strata span the Early Cretaceous to the earliest Late Cretaceous. The top age for the formation has been estimated to be Cenomanian. Earlier estimates placed the formation until the Campanian.^[1]

Cerro Barcino Formation
Stratigraphic range: Aptian-Cenomanian ~118–98 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Chubut Group
Sub-units	Las Plumas Cerro Castaño Puesto La Paloma Bayo Overo
Underlies	Puesto Manuel Arce Formation
Overlies	Los Adobes Formation
Lithology
Primary	Mudstone, sandstone
Other	Conglomerate, tuff
Location
Coordinates	43.8°S 68.6°W / -43.8; -68.6
Approximate paleocoordinates	44.7°S 35.1°W / -44.7; -35.1
Region	Chubut Province
Country	Argentina
Extent	Cañadón Asfalto Basin
Type section
Named for	Cerro Barcino
Cerro Barcino Formation (Argentina)

The formation was deposited in the Cañadón Asfalto Basin, a rift basin that started forming in the earliest Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation.

The Cerro Barcino Formation is the second-youngest unit of the Chubut Group, which also includes the older Los Adobes Formation. Both formations cover a vast area in Chubut Province, Argentina. The two formations are distinguished by geological features suggesting a distinct change in climate, from a wetter, flood plain environment in the Los Adobes to a much more arid, desert-like environment in the Cerro Barcino.^[1]

The Cerro Barcino Formation is subdivided into several subunits (members).^[1] From oldest to youngest:

• Bayo Overo (Correlates with both the Puesto La Paloma and the Cerro Castaño members)
• Puesto La Paloma
  • Characterized by arid plains interspersed with sand dunes
• Cerro Castaño
  • A return to more humid, flood-plain conditions
• Las Plumas

The Puesto La Paloma Member dates from ~118-113 Ma, the Cerro Castaño Member dates from ~113-100.5 Ma, correlating with the Albian, and the Las Plumas Member dates from ~100.5-98 Ma.^[2]

Fossil content

Possible rebbachisaurid remains are known from the La Paloma Member.^[1][2]

Lepidosaurs (Kaikaifilusaurus minimus and Priosphenodon minimus) and testudinatans (Chubutemys copelloi and Prochelidella cerrobarcinae) are also discovered from this formation.^[2]

Crurotarsans

Crocodylomorphs
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Barcinosuchus[3]	B. gradilis	Near El Escorial village, Chubut Province	Cerro Castaño Member	Skull, mandible, and postcranial remains	A peirosaurid. The first crocodyliform from the Chubut Group

Dinosaurs

Sauropods

Sauropods of the Cerro Barcino Formation
Genus	Species	Member	Material	Notes	Images
Chubutisaurus[4]	C. insignis	Bayo Overo	Two partial skeletons	A basal somphospondylan
Patagotitan[5]	P. mayorum	Cerro Castaño	Partial skeleton and other elements	A huge lognkosaur

Theropods

Theropods of the Cerro Barcino Formation
Genus	Species	Member	Material	Notes	Images
Abelisauroidea	Indeterminate	La Paloma member	Vertebrae	Very similar to the later and more large-bodied abelisauroids from South America such as Carnotaurus[6]
Genyodectes[7]	G. serus	Cerro Castaño	Partial snout	A possible ceratosaurid
"Megalosaurus"	"M." inexpectatus	Bayo Overo	Teeth	An indeterminate abelisaurid originally described as a species of Megalosaurus[8][9]
Tyrannotitan[10]	T. chubutensis	Cerro Castaño	Two partial skeletons and teeth	A giant giganotosaurin carcharodontosaurid

See also

• List of dinosaur-bearing rock formations
• La Amarga Formation, contemporaneous fossiliferous formation of the Neuquén Basin
• Lohan Cura Formation, contemporaneous fossiliferous formation of the Neuquén Basin
• Río Belgrano Formation, contemporaneous fossiliferous formation of the Austral Basin