The Regadera Formation (, 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 expo ...

of the

Bogotá savanna The Bogotá savanna is a savanna#Savanna ecoregions, 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 si ...

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. (Do not confuse with The Altiplano or the Altiplano Nariñense, both fur ...

Eastern Ranges The Eastern Ranges is an Australian rules football team that currently competes in the Talent League, the Victorian statewide under-18s competition. History Inaugural playing squad (1992) Honours *Premiers (2): 2002, 2013 *Runners-up (6): 199 ...

of the

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

. The predominantly

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

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 mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

beds intercalated, dates to the

Paleogene The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the fir ...

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 (, 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 formation, with sandstone ...

and is overlain by the

Usme Usme is the 5th locality of the Bogotá, Capital District, 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, Bogotá, San Cristóbal, Rafael Ur ...

and

Tilatá Formation The Tilatá Formation (, N1t, Tpt) is a formation (geology), geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Cordillera Oriental (Colombia), Eastern Ranges of the Colombian Andes. The formation consists of coarse to very coa ...

s. 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 (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. ...

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

* *

Maps

* * * * *

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) (; formerly known as INGEOMINAS) is a scientific Government agency, agency of the Colombian government in charge of contributing to the socioeconomic development of the nation through research in basic and ap ...

, 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