The Conejo Formation ( es, Formación Conejo, K₂C, Kscn) is a

fossiliferous A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

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

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 uppermost unit of the

Villeta Group The Villeta Group ( es, Grupo Villeta) is a geological group of the Eastern Ranges of the Colombian Andes, to the west of the Altiplano Cundiboyacense. The group, a sequence of shales, limestones and sandstones, is subdivided into various formati ...

, a sequence of

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 ...

s and

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) ...

s dates to 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 ...

period;

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...

and

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The ...

epochs, and has a maximum thickness of .

Etymology

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.Montoya & Reyes, 2005, p.29

Description

Lithologies

The Conejo Formation is characterised by a sequence of calcareous sandstones, containing

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

s, shales and the uppermost part sandstone and

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

banks.Montoya & Reyes, 2005, p.30 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

s '' Gloriaceras correai'', '' Protexamites cucaitaense'' and '' Codazziceras scheibei'' have been found.Luque et al., 2015Tchegliakova & Pérez, 1995Acosta & Ulloa, 2002, p.48

Stratigraphy and depositional environment

The Conejo Formation is the uppermost unit of the

. It overlies the

La Frontera Formation The La Frontera Formation ( es, Formación La Frontera, K2F, Ksf) is a geological formation, part of the Villeta Group, of the Altiplano Cundiboyacense and neighbouring areas of the Eastern Ranges of the Colombian Andes. The sequence of limestones ...

and is overlain by 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 age has been estimated on the basis of ammonites to be ranging from

. Stratigraphically, the lower part of the formation is time equivalent with the upper part of the

Chipaque Chipaque is a municipality and town in the Eastern Province of the department of Cundinamarca, Colombia. The municipality of is located at an altitude of in the Eastern Ranges of the Colombian Andes with its westernmost part situated in the Ea ...

,Montoya & Reyes, 2005, p.34 and

Loma Gorda Formation The Loma Gorda Formation ( es, Formación Loma Gorda, Kl, Kslg) is a fossiliferous geological formation of the Upper Magdalena Valley (VSM) and surrounding Central and Eastern Ranges of the Colombian Andes, extending from Cundinamarca in the nort ...

s.Acosta & Ulloa, 2002, p.22

Outcrops

The type locality of the Conejo Formation is located close to El Conejo Hill in Pontezuela,

Toca TOCA, formally trading as BARC (TOCA) Ltd, is an organiser of motorsport events in the United Kingdom. The company organises and administers the British Touring Car Championship (BTCC) and the support series to the BTCC, sometimes known as the T ...

, Boyacá.Acosta & Ulloa, 2001, p.43 Other

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial ...

s of the Conejo Formation have been noted in

Cucaita Cucaita is a municipality in the Central Boyacá Province, part of Boyacá Department, Colombia. The urban centre is situated on the Altiplano Cundiboyacense at a distance of from the department capital Tunja. Cucaita borders Sora in the north, T ...

, the urban areas of Boyacá and

Ventaquemada Ventaquemada is a town and municipality in the Central Boyacá Province, part of the Colombian department of Boyacá. Ventaquemada is located at a distance of from the capital Bogotá and from the departmental capital Tunja. The urban centre is ...

, around the

Puente de Boyacá The Puente de Boyacá (in English: Bridge of Boyacá) is a small bridge located at the Pan-American Highway, 110 km east of Bogotá and 14 km west from Tunja in a valley, crossing Teatinos River. Numerous monuments have been erected ...

, south of

Pesca Pesca is a town and municipality in the Colombian Department of Boyacá, part of the Sugamuxi Province, a subregion of Boyacá. The town is located in the Eastern Ranges of the Colombian Andes at altitudes between and . Pesca is west from t ...

, west of

Siachoque Siachoque is a town and municipality in the Central Boyacá Province, part of the Colombian department of Boyacá. Siachoque is situated on the Altiplano Cundiboyacense at a distance of from the department capital Tunja. It borders Toca in th ...

,Plancha 191, 1998 surrounding

Chiquinquirá Chiquinquirá is a town and municipality in the Colombian Department of Boyacá, part of the subregion of the Western Boyacá Province. Located some 115 km north of Bogotá, Chiquinquirá is above sea level and has a yearly average temp ...

and

Ubaté Ubaté (originally Villa San Diego de Ubaté) is a town and municipality in the Ubaté Province, part of Cundinamarca Department, Colombia. Ubaté is the capital of the province with the same name and situated in the Ubaté–Chiquinquirá Vall ...

,Plancha 190, 2009 between

Chivatá Chivatá is a town and municipality in the Central Boyacá Province, part of the Colombian department of Boyacá. The urban centre is situated at an altitude of on the Altiplano Cundiboyacense at from the department capital Tunja. It borders ...

and

Oicatá Oicatá is a town and municipality in the Central Boyacá Province, Departments of Colombia, Department of Boyacá Department, Boyacá, Colombia. The urban centre is situated on the Altiplano Cundiboyacense at an altitude of and a distance of f ...

, east of

Paipa Paipa is a town and municipality in the Tundama Province, a part of the Colombian department of Boyacá. Paipa borders Duitama, Firavitoba, Tibasosa, Sotaquirá and Tuta.Tibacuy Tibacuy is a municipality and town of Colombia in the department of Cundinamarca, in Sumapaz Province. Tibacuy is situated south of the Altiplano Cundiboyacense in the Eastern Ranges of the Colombian Andes at southeast of the capital Bogotá. ...

,Plancha 246, 1998 north and south of

Albán San José de Albán is a town and municipality in the Nariño Department, Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean ...

, southeast of Cachipay, east of

Anolaima Anolaima () is a municipality and township of Colombia in the department of Cundinamarca. It is located in the providence of Tequendama at West from Bogotá in between the cities of Facatativá and La Mesa. Anolaima is known as the Fruit Capit ...

, and

San Antonio del Tequendama San Antonio del Tequendama is a municipality and town of Colombia in the Tequendama Province part of the department of Cundinamarca. The municipality is located along the ''Serranía de Subía'' in the Tena Valley and borders Tena and Bojac� ...

, Cundinamarca.Plancha 227, 1998

Regional correlations

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 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 Formations Formations Formations