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 secondar ...

in South America whose strata span the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

to the earliest

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

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

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

. 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. Campanian s ...

. The formation was deposited in the

Cañadón Asfalto Basin The Cañadón Asfalto Basin ( es, Cuenca de Cañadón Asfalto) 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 for ...

, 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 wi ...

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 Chubut ( es, Provincia del Chubut, ; cy, Talaith Chubut) is a province in southern Argentina, situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes ra ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. 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.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 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.

Fossil content

Indeterminate

abelisaurid Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are foun ...

remains from the Puesto La Paloma Member. Possible indeterminate carcharodontosaurid remains. Indeterminate

Titanosauria Titanosaurs (or titanosaurians; members of the group Titanosauria) were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thr ...

remains. Also, an unnamed titanosauriform.

Crurotarsans

Dinosaurs

References

Bibliography

* * * * * * * {{ISBN, 0-520-24209-2 Geologic formations of Argentina Cretaceous Argentina Sandstone formations Mudstone formations Conglomerate formations Tuff formations Alluvial deposits Fluvial deposits Fossiliferous stratigraphic units of South America Paleontology in Argentina Geology of Chubut Province

Fossil content

Crurotarsans

Dinosaurs

See also

References

Bibliography