The Chorrera Formation ( es, Formación Chorrera, N_2ch) is a

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

. The formation consists of coarse to very coarse conglomerates. The Chorrera Formation dates to the

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

period;

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Montehermosan The Montehermosan age is a period of geologic time (6.8–4.0 Ma) within the Miocene and Pliocene epochs of the Neogene used more specifically with South American Land Mammal Ages. It follows the Huayquerian and precedes the Chapadmalalan The C ...

Chapadmalalan The Chapadmalalan age is a period of geologic time (4.0–3.0 Ma) within the Pliocene epoch of the Neogene used more specifically with South American Land Mammal Ages. It follows the Montehermosan and precedes the Uquian age. Fossil content F ...

in the SALMA classification), and has a maximum thickness of .

Etymology

The formation was defined by Helmens and Van der Hammen in 1995 after the La Chorrera waterfall in Subachoque.Montoya & Reyes, 2005, p.67

Description

Lithologies

The Chorrera Formation consists of coarse to very coarse conglomerates.

Stratigraphy and depositional environment

The Chorrera Formation unconformably overlies the

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 ...

Guadalupe Group The Guadalupe Group ( es, Grupo Guadalupe, K2G, Ksg) is a geological group of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The group, a sequence of shales and sandstones, is subdivided into three formations; Arenisca Dur ...

. The formation is overlain by the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Subachoque Formation The Subachoque Formation ( es, Formación Subachoque, Q1su) is a formation (geology), geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Cordillera Oriental (Colombia), Eastern Ranges of the Colombian Andes. The formation cons ...

. The age of the Chorrera Formation has been estimated to be

Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

based on its stratigraphical position. The depositional environment is characterised by alluvial fans formed during the main phase of tectonic uplift of the Eastern Ranges in the Late Pliocene. Dutch geologist Salomon Kroonenberg, who studied the Neogene uplift of the Eastern Andes in Colombia, defines the main stage of uplift between six and four million years ago. Other Dutch geologists Helmens, Van der Hammen and Hooghiemstra have pushed back this uplift phase to between 4.5 and 3 Ma.Molnar, 2004, p.75 The facies origin of the Chorrera Formation is comparable to the

Marichuela Formation The Marichuela Formation ( es, Formación Marichuela, N1m) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of coarse to very coarse conglomerates. The Ma ...

, outcropping on the eastern edge of the Bogotá savanna, yet different in stratigraphic position. The deposition of sediments of the Chorrera Formation is time-equivalent with the explosive phase of the Paipa–Iza volcanic complex, active between 4.7 and 3.6 Ma,Monsalve et al., 2011, p.120 and the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

to Late Pliocene Tilatá Formation.

Outcrops

The Chorrera Formation is found at its type locality in the synclinal of the Río Frío, east of Subachoque, Cundinamarca.

References

Bibliography

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External links

* {{citation , last1=Gómez , first1=J. , last2=Montes , first2=N.E. , last3=Nivia , first3=Á. , last4=Diederix , first4=H. , year=2015 , title=Plancha 5-09 del Atlas Geológico de Colombia 2015 – escala 1:500,000 , url=https://www.researchgate.net/publication/309533589 , publisher=

Servicio Geológico Colombiano 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 ...

, pages=1 , accessdate=2017-03-16 Geologic formations of Colombia Neogene Colombia Pliocene Series of South America Chapadmalalan Montehermosan Conglomerate formations Alluvial deposits Formations Formations