El Peñón Formation

The El Peñón Formation (Spanish: Formación El Peñón, Kipe) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of calcareous shales and siltstones and dates to the Early Cretaceous period; Late Aptian epoch and has a measured thickness at its type section of 381 metres (1,250 ft). Ammonite fossils have been found in the formation, deposited in a shallow marine platform environment.

El Peñón Formation Stratigraphic range: Late Aptian ~115–112 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Villeta Group
Underlies	Capotes Formation
Overlies	Trincheras Formation
Thickness	more than 381 m (1,250 ft)
Lithology
Primary	Calcareous shale
Other	Siltstone, gypsum
Location
Coordinates	5°15′13″N 74°20′28″W
Region	Altiplano Cundiboyacense Eastern Ranges, Andes
Country	Colombia
Type section
Named for	El Peñón
Named by	Ulloa
Location	El Peñón
Year defined	1982
Coordinates	5°15′13″N 74°20′28″W
Region	Cundinamarca
Country	Colombia
Thickness at type section	381 m (1,250 ft)
Paleogeography of Northern South America 120 Ma, by Ron Blakey

Etymology

The formation was defined and named in 1982 by Ulloa after El Peñón, Cundinamarca.[1]

Description

Lithologies

The El Peñón Formation has at is type section a thickness of 381 metres (1,250 ft),[2] and is characterised by a sequence of calcareous shales and siltstones. The middle part of the sequence contains gypsum.[3] Fossils of the ammonites Cheloniceras sp. and Epicheloniceras sp. aff. carlosacostai have been found in the El Peñón Formation.[1]

Stratigraphy and depositional environment

The El Peñón Formation, part of the Villeta Group, conformably overlies the Trincheras Formation and is conformably overlain by the Capotes Formation.[4] The age has been estimated to be Late Aptian.[1] Stratigraphically, the formation is time equivalent with the Tablazo Formation and a lateral facies equivalent of the Socotá Formation.[5] The formation has been deposited in a shallow marine platform environment.[1] In the Late Aptian, central Colombia was dominated by shallow marine carbonate platform environments.[6]

Outcrops

Type locality of the El Peñón Formation to the west of the Altiplano Cundiboyacense

The El Peñón Formation, restricted to Cundinamarca, is locally found around its type locality,[1] between Bituima and Guayabal de Síquima,[7] and along the road from Villeta to Sasaima.[2]

Regional correlations

Cretaceous stratigraphy of the central Colombian Eastern Ranges

Age	Paleomap	VMM	Guaduas-Vélez		W Emerald Belt		Villeta anticlinal		Chiquinquirá- Arcabuco	Tunja- Duitama	Altiplano Cundiboyacense		El Cocuy
Maastrichtian		Umir	Córdoba		Seca		eroded		Guaduas				Colón-Mito Juan
					Umir				Guadalupe
Campanian					Córdoba
					Oliní
Santonian		La Luna	Cimarrona - La Tabla										La Luna
Coniacian			Oliní				Villeta	Conejo		Chipaque
			Güagüaquí	Loma Gorda	undefined			La Frontera
Turonian				Hondita	La Frontera	Otanche
Cenomanian		Simití	hiatus		La Corona			Simijaca					Capacho
					Pacho Fm.			Hiló - Pacho	Churuvita	Une			Aguardiente
Albian					Hiló				Chiquinquirá	Tibasosa	Une
		Tablazo			Tablazo			Capotes - La Palma - Simití	Simití				Tibú-Mercedes
Aptian					Capotes			Socotá - El Peñón	Paja		Fómeque
		Paja			Paja	El Peñón		Trincheras					Río Negro
							La Naveta
Barremian
Hauterivian						Muzo					Cáqueza	Las Juntas
		Rosablanca							Ritoque
Valanginian					Ritoque	Furatena	Útica - Murca		Rosablanca	hiatus		Macanal
					Rosablanca
Berriasian		Cumbre			Cumbre				Los Medios			Guavio
		Tambor			Arcabuco				Cumbre
Sources

See also

Geology of the Eastern Hills

Geology of the Ocetá Páramo

Geology of the Altiplano Cundiboyacense

References

1. Acosta & Ulloa, 2002, p.42
2. Acosta & Ulloa, 2001, p.27
3. Acosta & Ulloa, 2001, p.29
4. Acosta & Ulloa, 2001, p.30
5. Acosta & Ulloa, 2001, p.16
6. Villamil, 2012, p.164
7. Plancha 227, 1998

Bibliography

• Acosta Garay, Jorge E., and Carlos E. Ulloa Melo. 2002. Mapa Geológico del Departamento de Cundinamarca - 1:250,000 - Memoria explicativa, 1–108. INGEOMINAS. Accessed 2017-04-26.
• Acosta Garay, Jorge, and Carlos E. Ulloa Melo. 2001. Geología de la Plancha 208 Villeta - 1:100,000, 1-84. INGEOMINAS. Accessed 2017-06-05.
• Villamil, Tomas. 2012. Chronology Relative Sea Level History and a New Sequence Stratigraphic Model for Basinal Cretaceous Facies of Colombia, 161–216. Society for Sedimentary Geology (SEPM).

Maps

• Ulloa, Carlos, and Jorge Acosta. 1998. Plancha 208 - Villeta - 1:100,000, 1. INGEOMINAS. Accessed 2017-06-06.
• Ulloa, Carlos E; Erasmo Rodríguez, and Jorge E. Acosta. 1998. Plancha 227 - La Mesa - 1:100,000, 1. INGEOMINAS. Accessed 2017-06-06.

External links

• Gómez, J.; N.E. Montes; Á. Nivia, and H. Diederix. 2015. Plancha 5-09 del Atlas Geológico de Colombia 2015 – escala 1:500,000, 1. Servicio Geológico Colombiano. Accessed 2017-03-16.