The Cerro Barcino Formation (also known as the Gorro Frigio Formation) is a geological

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

in South America whose strata span the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

to the earliest

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

. The top age for the formation has been estimated to be

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

. Earlier estimates placed the formation until the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

. The formation was deposited in the

Cañadón Asfalto Basin The Cañadón Asfalto Basin () is an irregularly shaped sedimentary basin located in north-central Patagonia, Argentina. The basin stretches from and partly covers the North Patagonian Massif in the north, a high forming the boundary of the basin ...

, a

rift basin In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

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 Chubut may refer to: * Chubut Province, Argentina * Chubut River in the Chubut Province * Chubut steamer duck The Chubut steamer duck or white-headed flightless steamer duck (''Tachyeres leucocephalus'') is a flightless duck endemic to Argenti ...

, which also includes the older

Los Adobes Formation Los Adobes Formation is an Early Cretaceous (Aptian) geologic formation in Chubut Province, in the Cañadón Asfalto Basin of central Patagonia, Argentina. The formation belongs to the Chubut Group and represents the Early Cretaceous K1 megaseque ...

. Both formations cover a vast area in

Chubut Province Chubut ( from Tehuelche language, Tehuelche 'transparent'; ) is a provinces of Argentina, province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. The two formations are distinguished by geological features suggesting a distinct change in climate, from a wetter,

flood plain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

environment in the Los Adobes to a much more arid, desert-like environment in the Cerro Barcino.Rauhut et al., 2003 The Cerro Barcino Formation is subdivided into several subunits (

members Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

). 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 dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

s * 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.

Fossil content

Possible

rebbachisaurid Rebbachisauridae is a Family (biology), family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, Europe and possibly Central Asia. Taxonomy In 1990 sauropod specialist Jack M ...

remains are known from the La Paloma Member.

Lepidosaur The Lepidosauria (, from Greek meaning ''scaled lizards'') is a superorder or subclass of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata also includes lizards and snakes. Squamata contains over 9,000 species, making it by ...

s ('' Kaikaifilusaurus minimus'' and '' Priosphenodon minimus'') and

Testudinata Testudinata is the group of all tetrapods with a true turtle shell. It includes both modern turtles (Testudines) and many of their extinct, shelled relatives (stem-turtles), though excluding ''Odontochelys'' and ''Eorhynchochelys,'' which are pla ...

('' Chubutemys copelloi'' and '' Prochelidella cerrobarcinae'') are also discovered from this formation.

Crurotarsans

Dinosaurs

Sauropods

Theropods

References

Bibliography

* * * * {{citation , last1=Weishampel , first1=David B. , author2-link=Peter Dodson , last2=Dodson , first2=Peter , author3-link=Halszka Osmólska , last3=Osmólska , first3=Halszka , year=2004 , title=The Dinosauria, 2nd edition , url=https://books.google.com/books?id=vtZFDb_iw40C , publisher=Berkeley: University of California Press , pages=1–880 , accessdate=2019-02-21 , isbn=0-520-24209-2 , author1-link=David B. Weishampel Geologic formations of Argentina Cretaceous Argentina Sandstone formations Mudstone formations of Argentina Conglomerate formations Tuff formations of Argentina Alluvial deposits Fluvial deposits Fossiliferous stratigraphic units of South America Paleontology in Argentina Geology of Chubut Province