The Castillo Formation is an

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

(

Burdigalian The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...

Colhuehuapian The Colhuehuapian age is a period of geologic time (21.0–17.5 Ma) within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Deseadan and precedes the Santacrucian ag ...

Santacrucian The Santacrucian age is a period of geologic time (17.5 – 16.3 Mya (unit), Ma) within the Early Miocene epoch of the Neogene, used more specifically with South American land mammal age, SALMA classification in South America. It follows the Colhue ...

in the SALMA classification) geologic formation in the Falcón Basin of

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. The formation unconformably overlies the Matatere, Misoa, El Paují and Jarillal Formations.Urbani & Mendi, 2010, p.17 The Castillo Formation is overlain by Quaternary alluvium and in places by the Capadare Formation.Urbani & Mendi, 2010, p.19 The formation, deposited in a calm near-shore lagoonal brackish environment, with possibly fluvial influence, has provided a rich assemblage of fossil crocodylians, turtles, giant sloths and various types of fish.

Description

The Castillo Formation crops out cover a wide semicircular area that extends through the northwestern Venezuelan states of Falcón and Lara. During Oligocene to Miocene times, the formation formed the northwest to southeast edge of the Falcón Basin.Solórzano et al., 2018a, p.3 The formation, with a minimum thickness of ,Rincón et al., 2014, p.510 has formerly been regarded as

Late Oligocene The Chattian is, in the geologic timescale The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the pro ...

in age (Wheeler, 1960), but more recent workers, regard it to be Early Miocene. The Castillo Formation at Cerro La Cruz comprises of clayey

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

s, interbedded with numerous thin (less than )

hardground Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limeston ...

units. The strata are underlain and overlain by sandstones, and the upper are gypsiferous. The formation was deposited in a calm near-shore marine to brackish

lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...

al environment with possibly

fluvial A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...

influence. Elements of the fauna are consistent with the hypothesis that a tributary and/or

delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

of the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

existed in this area of northwestern Venezuela during Early Miocene times. Other authors did not find convincing results to support this hypothesis.Rincón et al., 2014, p.522

Fossil content

In the formation, apart from

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

s, fossils of the

giant sloth Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. They varied widely in size with the largest, belonging to genera '' Lestodon'', ''Eremotherium'' and ''Megatherium'', being around the size of elephants. ...

'' Baraguatherium takumara'', the turtle '' Chelus colombiana'', the crocodylians '' Siquisiquesuchus venezuelensis'',Siquisique
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org ''

Purussaurus ''Purussaurus'' is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from the Friasian to the Huayquerian in the SALMA classification. It is known from skull material found in the Brazilian and Peruvian Am ...

'', ''

Caiman A caiman ( (also spelled cayman) from Taíno language, Taíno ''kaiman'') is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family (biology), family, the other being alligators. ...

'',Solórzano et al., 2018a, p.12 '' Gryposuchus'',Solórzano, 2018b, p.121 and indeterminate other crocodylians,Solórzano et al., 2018, p.1 and the pelican-like '' Pelagornis sp.'' have been found. The pelican-like fossil is the oldest of South America.Tres curiosos animales prehistóricos emergen del subsuelo venezolano
Hallan restos de tres animales prehistóricos en Lara
Other fossils reported from the formation are:Cerro La Cruz, Unit C
at

.orgCerro La Cruz
at

.org *

silky shark The silky shark (''Carcharhinus falciformis''), also known by numerous names such as blackspot shark, gray whaler shark, olive shark, ridgeback shark, sickle shark, sickle-shaped shark and sickle silk shark, is a species of requiem shark, in the ...

(''Carcharhinus falciformis'') *

wahoo The wahoo (''Acanthocybium solandri'') is a scombrid fish found worldwide in tropical and subtropical seas. In Hawaii, the wahoo is known as ono. The species is sometimes called hoo in the United States. It is best known to sports fishermen, a ...

(''Acanthocybium sp.'') *

barracuda A barracuda is a large, predatory, ray-finned, saltwater fish of the genus ''Sphyraena'', the only genus in the family Sphyraenidae, which was named by Constantine Samuel Rafinesque in 1815. It is found in tropical and subtropical oceans worldw ...

(''Sphyraena sp.'') * '' Carcharhinus cf. obscurus'' * '' Carcharhinus cf. perezi'' * '' Hemipristis serra'' * '' aff. Prosqualodon australis'' * '' Bairdemys sp.'' * '' Rhinoptera sp.'' * '' Scirrotherium sp.'' * Arecaceae indet. * Astrapotheriidae indet. * Iniidae indet. * Litopterna indet. * Mylodontidae indet. * Platanistoidea indet. * Squalidae indet. * Tardigrada indet. * Trionychoidea indet.

References

Bibliography

* * * * * * {{citation , last1=Urbani , first1=Franco , last2=Mendi , first2=David , year=2010 , title=Notas sobre la discordancia del margen sur de la cuenca Oligo-Miocena de Falcón estados Lara, Falcón y Yaracuy, Venezuela , url=https://www.researchgate.net/publication/289375537 , journal=Boletín de la Academia de Ciencias Físicas, Matemáticas y Naturales , volume=LXX , pages=9–25 , accessdate=2017-08-15

Description

Fossil content

See also

References

Bibliography

Further reading