The Regadera Formation ( es, Formación Regadera, E₂r, Tpr) 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 The Bogotá savanna is a montane savanna, located in the southwestern part of the Altiplano Cundiboyacense in the center of Colombia. The Bogotá savanna has an extent of and an average altitude of . The savanna is situated in the Eastern Range ...

Altiplano Cundiboyacense The Altiplano Cundiboyacense () is a high plateau located in the Eastern Cordillera of the Colombian Andes covering parts of the departments of Cundinamarca and Boyacá. The altiplano corresponds to the ancient territory of the Muisca. The Alti ...

Eastern Ranges The Eastern Ranges is an Australian rules football team in the NAB League, the Victorian statewide under-18s competition. The club is a founding member of the competition (1992) and has produced several players for the Australian Football Leagu ...

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 predominantly

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) ...

and conglomeratic formation, with pink

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

beds intercalated, dates to the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

period; Middle to Late Eocene epoch, and has a maximum thickness of .

Etymology

The formation was first described by Hubach in 1931 as part of the Usme Formation and redefined and named in 1963 by Julivert after the La Regadera Reservoir.Montoya & Reyes, 2005, p.60

Description

Lithologies

The Regadera Formation consists mainly of quartz arenitic

and conglomerates with some

beds.Bayona et al., 2010, p.5

Stratigraphy and depositional environment

The Regadera Formation overlies the

Bogotá Formation The Bogotá Formation ( es, Formación Bogotá, E1-2b, Tpb, Pgb) is a geological formation of the Eastern Hills and Bogotá savanna on the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly shale and siltstone form ...

and is overlain by the

Usme Usme is the 5th locality of the Capital District of Bogotá, capital city of Colombia. Usme is located in the south of Bogotá, bordering to the north the localities of San Cristóbal, Rafael Uribe Uribe and Tunjuelito, to the west the locali ...

and Tilatá Formations. The age has been estimated, based on palynological data of '' Echitriporites trianguliformis var. orbicularis'', '' Nothofagidites sp.'' and '' Multiporopollenites pauciporatus'', to be Middle to Late Eocene.Montoya & Reyes, 2005, p.64 The depositional environment has been interpreted as a

braided river A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, ''aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment l ...

setting.Bayona et al., 2010, p.7

Outcrops

The Regadera Formation is apart from its type locality in the synclinal of

, the valley of the

Tunjuelo River The Tunjuelo or Tunjuelito River is a river on the Bogotá savanna and a left tributary of the Bogotá River. The river, with a length of originates in the Sumapaz Páramo and flows northward through the Usme Synclinal to enter the Colombian capit ...

, found in the synclinal of Sisga. In the Tunjuelo River valley, the Regadera Formations is present in the escarpments on the river banks.Bayona et al., 2010, p.11

Regional correlations

Notes and references

Notes

References

Bibliography

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Maps

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External links

* {{cite LSA , last=Gómez , first=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_Plancha_5-09_del_Atlas_Geologico_de_Colombia_2015 , 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 Paleogene Colombia Eocene Series of South America Divisaderan Mustersan Casamayoran Bartonian Stage Lutetian Stage Priabonian Stage Sandstone formations Conglomerate formations Fluvial deposits Formations Geography of Cundinamarca Department Geography of Bogotá