The La Quinta Formation is a

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

geologic

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 ...

which crops out in the

Cordillera de Mérida The Cordillera de Mérida is a series of mountain ranges, or massif, in northwestern Venezuela. The Cordillera de Mérida is a northeastern extension of the Andes Mountains and the most important branch of the Venezuelan Andes. The ranges run sou ...

and

Serranía del Perijá The Serranía del Perijá, Cordillera de Perijá or Sierra de Perijá is a mountain range, an extension of the eastern Andean branch ( Cordillera Oriental), in northern South America, between Colombia and Venezuela Venezuela (; ), offici ...

of western

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

and northeastern Colombia. The formation is also present in the subsurface of the Cesar-Ranchería and

Maracaibo Basin The Maracaibo Basin, also known as Lake Maracaibo natural region, Lake Maracaibo depression or Lake Maracaibo Lowlands, is a foreland basin and one of the eight natural regions of Venezuela, found in the northwestern corner of Venezuela in South A ...

s. At its type locality near

La Grita La Grita is a town in the north west of Táchira state, Venezuela. It has a population of 80.000. Located in an Andean valley, La Grita has a beautiful natural setting and fertile land. The town includes colonial style houses and open plazas. Th ...

Táchira Táchira State ( es, Estado Táchira, ) is one of the 24 states of Venezuela. The state capital is San Cristóbal. Táchira State covers a total surface area of and as of the 2011 census, had a population of 1,168,908. At the end of the 19t ...

, it consists of a basal

dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyol ...

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

followed by interlayered

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

s, siltstones and rare

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s.Barret ''et al.'', 2008, p.164

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

remains including ''

Laquintasaura ''Laquintasaura'' is a genus of Venezuelan ornithischian dinosaur containing only the type species ''Laquintasaura venezuelae''. The species was the first dinosaur to have been identified from Venezuela. It is known from extensive remains, all ...

'',Barret ''et al.'', 2014 '' Tachiraptor'', and '' Perijasaurus'' are among the fossils that have been recovered from the formation.Weishampel, ''et al.'' (2004). "Dinosaur distribution." Pp. 517-607 U–Pb zircon analysis demonstrates that the formation dates to 200.91+0.55 Ma at its base and a maximum age of 174.8 Ma.

Paleofauna

Regional correlations

Notes

References

Bibliography

* * Barrett, P. M., R. J. Butler, S. C. Moore-Fay, F. E. Novas, J. M. Moody, J. M. Clark, and M. R. Sänchez-Villagra. ‘Dinosaur Remains from the La Quinta Formation (Lower or Middle Jurassic) of the Venezuelan Andes’. Paläontologische Zeitschrift 82, no. 2 (2008): 163–177. * Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .

Maps

* * * * * * {{cite LSA , last=Hernández , first=Marina , last2=Clavijo , first2=Jairo , year=2008 , title=Plancha 48 - La Jagua de Ibirico - 1:100,000 , url=https://drive.google.com/open?id=0BwFQPMJEi17QeGxwUUxmSHEwdm8 , publisher=

INGEOMINAS The Colombian Geological Survey (CGS) ( es, Servicio Geológico Colombiano; formerly known as INGEOMINAS) is a scientific agency of the Colombian government in charge of contributing to the socioeconomic development of the nation through research ...