Conejo Formation
Conejo Formation | |
---|---|
Stratigraphic range: Turonian-Santonian ~90–83.6 Ma | |
Type | Geological formation |
Unit of | Villeta Group |
Underlies | Guadalupe Group |
Overlies | La Frontera Formation |
Thickness | up to 1,022 m (3,353 ft) |
Lithology | |
Primary | Sandstone, shale |
Other | Limestone |
Location | |
Coordinates | 5°35′40.7′′N 73°12′59.6′′W / 5.594639°N 73.216556°W / 5.594639; -73.216556 |
Region | Altiplano Cundiboyacense Eastern Ranges, Andes |
Country | Colombia |
Type section | |
Named for | El Conejo Hill |
Named by | Renzoni |
Location | Toca, Boyacá |
Year defined | 1981 |
Coordinates | 5°35′40.7′′N 73°12′59.6′′W / 5.594639°N 73.216556°W / 5.594639; -73.216556 |
Region | Cundinamarca, Boyacá |
Country | Colombia |
Paleogeography of Northern South America 90 Ma, by Ron Blakey |
The Conejo Formation (Spanish: Formación Conejo, K2C, Kscn) is a fossiliferous geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The uppermost unit of the Villeta Group, a sequence of shales and sandstones dates to the Late Cretaceous period; Turonian, Coniacian and Santonian epochs, and has a maximum thickness of 1,022 metres (3,353 ft).
Etymology
[edit ]The formation was named in 1967 and published in 1981 by Renzoni, named after El Conejo Hill in Pontezuela, Toca, Boyacá, west of the Copa Reservoir.[1] [2]
Description
[edit ]Lithologies
[edit ]The Conejo Formation is characterised by a sequence of calcareous sandstones, containing ammonites, shales and the uppermost part sandstone and limestone banks.[3] In the Conejo Formation, fossils of Protopholoe colombiana , Archaeglobigerina blowi , Dicarinella concavata , Dicarinella primitiva , Sigalitruncana sigali , Marginotruncana sp. ct. M. renzi , Marginotruncana angusticarenata , Marginotruncana sp. cf. M.sinuosa , Rosita tornicata , Heterohelix globulosa , Heterohelix reussi , Whiteinella inornata , Hedbergella sp. , and the ammonites Gloriaceras correai , Protexamites cucaitaense and Codazziceras scheibei have been found.[4] [5] [6]
Stratigraphy and depositional environment
[edit ]The Conejo Formation is the uppermost unit of the Villeta Group.[7] It overlies the La Frontera Formation and is overlain by the Guadalupe Group. The age has been estimated on the basis of ammonites to be ranging from Turonian to Santonian.[8] Stratigraphically, the lower part of the formation is time equivalent with the upper part of the Chipaque,[8] and Loma Gorda Formations.[7]
Outcrops
[edit ]The type locality of the Conejo Formation is located close to El Conejo Hill in Pontezuela, Toca, Boyacá.[2] Other outcrops of the Conejo Formation have been noted in Cucaita,[4] [5] the urban areas of Boyacá and Ventaquemada, around the Puente de Boyacá, south of Pesca, west of Siachoque,[9] surrounding Chiquinquirá and Ubaté,[10] between Chivatá and Oicatá,[2] east of Paipa,[11] west of Tibacuy,[12] north and south of Albán, southeast of Cachipay, east of Anolaima, and San Antonio del Tequendama, Cundinamarca.[13]
Regional correlations
[edit ]
See also
[edit ]References
[edit ]- ^ Montoya & Reyes, 2005, p.29
- ^ a b c Acosta & Ulloa, 2001, p.43
- ^ Montoya & Reyes, 2005, p.30
- ^ a b Luque et al., 2015
- ^ a b Tchegliakova & Pérez, 1995
- ^ Acosta & Ulloa, 2002, p.48
- ^ a b Acosta & Ulloa, 2002, p.22
- ^ a b Montoya & Reyes, 2005, p.34
- ^ Plancha 191, 1998
- ^ Plancha 190, 2009
- ^ Planchas 171 & 191, 2005
- ^ Plancha 246, 1998
- ^ Plancha 227, 1998
Bibliography
[edit ]- Acosta, Jorge E.; Ulloa, Carlos E. (2002), Mapa geológico del Departamento de Cundinamarca 1:250,000 - Memoria Explicativa, INGEOMINAS, pp. 1–108
- Acosta Garay, Jorge; Ulloa Melo, Carlos E. (2001), Geología de la Plancha 208 Villeta - 1:100,000 (PDF), INGEOMINAS, pp. 1–84, retrieved 2017年03月16日 Archived 2017年03月24日 at the Wayback Machine
- Luque, Javier; Hourdez, Stéphane; Vinn, Olev (2015), "A new fossil bristle worm (Annelida: Polychaeta: Aphroditiformia) from the late Cretaceous of tropical America", Journal of Paleontology , 89 (2): 257–261, Bibcode:2015JPal...89..257L, doi:10.1017/jpa.2014.22 , retrieved 2017年04月04日
- Montoya Arenas, Diana María; Reyes Torres, Germán Alfonso (2005), Geología de la Sabana de Bogotá, INGEOMINAS, pp. 1–104
- Tchegliakova, Nadejda; Pérez, Vladimir (1995), "Registro de la Zona bioestratigrafica Dicarinella concavata (Foraminiferida) en el Extremo noroccidental de Suramerica (Colombia)", Geología Colombiana , 19: 131–143, retrieved 2017年04月06日
- Villamil, Tomas (2012), Chronology Relative Sea Level History and a New Sequence Stratigraphic Model for Basinal Cretaceous Facies of Colombia, Society for Sedimentary Geology (SEPM), pp. 161–216
Maps
[edit ]- Ulloa, Carlos E; Rodríguez, Erasmo (2009), Plancha 170 - Vélez - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Renzoni, Giancarlo; Rosas, Humberto (2009), Plancha 171 - Duitama - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Fuquen M., Jaime A; Osorno M, José F. (2009), Plancha 190 - Chiquinquirá - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Renzoni, Giancarlo; Rosas, Humberto; Etayo Serna, Fernando (1998), Plancha 191 - Tunja - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Ulloa, Carlos; Acosta, Jorge (1998), Plancha 208 - Villeta - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Montoya, Diana María; Reyes, Germán (2009), Plancha 209 - Zipaquirá - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Terraza, Roberto; Moreno, Giovanni; Buitrago, José A.; Pérez, Adrián; Montoya, Diana María (2010), Plancha 210 - Guateque - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Ulloa, Carlos E; Rodríguez, Erasmo; Acosta, Jorge E. (1998), Plancha 227 - La Mesa - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Acosta, Jorge E.; Guatame, Rafael; Torres, Oscar; Solano, Frank (1999), Plancha 245 - Girardot - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Acosta, Jorge E.; Ulloa, Carlos E. (1998), Plancha 246 - Fusagasugá - 1:100,000, INGEOMINAS, p. 1, retrieved 2017年06月06日
- Velandia, Francisco; Cepeda, Héctor (2005), Planchas 171 & 191 - Geología sector del sur del municipio de Paipa (Boyacá) - 1:25,000, INGEOMINAS
External links
[edit ]- Gómez, J.; Montes, N.E.; Nivia, Á.; Diederix, H. (2015), Plancha 5-09 del Atlas Geológico de Colombia 2015 – escala 1:500,000, Servicio Geológico Colombiano, p. 1, retrieved 2017年03月16日
- Geologic formations of Colombia
- Cretaceous Colombia
- Upper Cretaceous Series of South America
- Turonian Stage
- Coniacian Stage
- Santonian Stage
- Shale formations
- Sandstone formations
- Fossiliferous stratigraphic units of South America
- Paleontology in Colombia
- Altiplano Cundiboyacense
- Geography of Cundinamarca Department
- Geography of Boyacá Department