La Frontera Formation

La Frontera Formation
Stratigraphic range: Turonian
~93.9–89.8 Ma
↓
Type Geological formation
Unit of Villeta Group
Underlies Conejo Formation
Overlies Simijaca Fm., La Corona Gb.
Thickness up to 206 metres (680 ft)
Lithology
Primary Lydite
Other Limestone
Location
Coordinates 4°54′40″N 74°27′50″W / 4.91111°N 74.46389°W / 4.91111; -74.46389Coordinates: 4°54′40″N 74°27′50″W / 4.91111°N 74.46389°W / 4.91111; -74.46389
Region Altiplano Cundiboyacense
Eastern Ranges, Andes
Country  Colombia
Type section
Named for La Frontera quarry
Named by Cáceres & Etayo
Location Albán
Year defined 1969
Coordinates 4°54′40″N 74°27′50″W / 4.91111°N 74.46389°W / 4.91111; -74.46389
Region Cundinamarca, Boyacá
Country  Colombia

Paleogeography of Northern South America
90 Ma, by Ron Blakey

The La Frontera Formation (Spanish: 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 lydites dates to the Late Cretaceous period; Turonian epoch and has a maximum thickness of 206 metres (676 ft).

Fossils of Yaguarasaurus columbianus were said to be found in this formation (listed as "La Frontera Member"), although the geological mapping of the area state the time-equivalent Hondita Formation as the stratigraphic unit present in the Quebradas El Ocal and Itaibe in Huila. The La Frontera Formation does not outcrop south of Cundinamarca. A high diversity of ammonites has been found in the La Frontera Formation.

Etymology

The formation was first described by Hubach in 1931 and elevated to formation in 1969 by Cáceres and Etayo.[1] The formation is named after the quarry La Frontera near Albán, Cundinamarca.[2]

Description

Lithologies

The La Frontera Formation is characterised by a lower part consisting of limestones and an upper part comprising lydites.[1]

Stratigraphy and depositional environment

The La Frontera Formation overlies the Simijaca Formation and is overlain by the Conejo Formation, all units belong to the Villeta Group. The age has been estimated to be Turonian.[1] Stratigraphically, the formation is time equivalent with the Chipaque, Hondita and La Luna Formations.[3] The formation has been deposited in an open marine platform to submarine fan setting.[4] The deposition is represented by a maximum flooding surface.[5] The formation contains concretions and a high diversity of ammonites;[6] Wrightoceras munieri, Vascoceras cf. constrictum, Vascoceras cf. venezolanum, Kamerunoceras sp., Kamerunoceras cf. turoniense, Hoplitoides cf. lagiraldae, Codazziceras ospinae, Coilopoceras cf. newelli,[7] Hoplitoides wohltmanni, Neoptychites crassus, Hoplitoides ingens, Mammites sp., ?Fagesia sp., and Prionocycloceras sp.[8] Also the bivalves Anomia colombiana and Inoceramus sp. have been found in the La Frontera Formation.[2]

Yaguarasaurus

Fossils of Yaguarasaurus columbianus were described as coming from the "La Frontera Member", part of the "Villeta Formation", in the Quebrada El Ocal, 26 kilometres (16 mi) southwest of Neiva, Huila,[9][10] and in the Quebrada Itaibe 78 kilometres (48 mi) southwest of Neiva,[11] although in these areas the time-equivalent Hondita Formation is mapped.[12][13]

Outcrops

Type locality of the La Frontera Formation to the west of the Bogotá savanna

The La Frontera Formation is apart from its type locality, found at surface in the north of the Bogotá savanna, in the Tabio anticlinal, along the road Ubaté-Carmen de Carupa,[1] north and east of Chiquinquirá,[14] south of Cachipay,[15] to a thin band east of Viotá.[16]

Regional correlations

Cretaceous stratigraphy of the central Colombian Eastern Ranges
AgePaleomapVMMGuaduas-VélezW Emerald BeltVilleta anticlinalChiquinquirá-
Arcabuco		Tunja-
Duitama		Altiplano CundiboyacenseEl Cocuy
MaastrichtianUmir Fm.Córdoba Fm.Seca Fm.erodedGuadalupe Gp.Colón-Mito Juan Fm.
Umir Fm.
CampanianCórdoba Fm.
Oliní Gp.
SantonianLa Luna Fm.Cimarrona Fm. - La Tabla Fm.La Luna Fm.
ConiacianOliní Gp.Conejo Fm.Chipaque Fm.
Güagüaquí Gp
Loma Gorda Fm.undefinedLa Frontera Fm.
TuronianHondita Fm.La Frontera Fm.Otanche Fm.
CenomanianSimití Fm.hiatusLa Corona Gb.Simijaca Fm.Capacho Fm.
Pacho Fm.Hiló Fm. - Pacho Fm.Churuvita Fm.Une Fm.Aguardiente Fm.
AlbianHiló Fm.Chiquinquirá Sst.Tibasosa Fm.Une Fm.
Tablazo Fm.Tablazo Fm.Capotes Fm. - La Palma Fm. - Simití Fm.Simití Fm.Tibú-Mercedes Fm.
AptianCapotes Fm.Socotá Fm. - El Peñón Fm.Paja Fm.Fómeque Fm.
Paja Fm.Paja Fm.El Peñón Fm.Trincheras Fm.Río Negro Fm.
La Naveta Fm.
Barremian
HauterivianMuzo Fm.
Cáqueza Gp
Las Juntas Fm.
Rosablanca Fm.Ritoque Fm.
ValanginianRitoque Fm.Furatena Fm.Útica Fm. - Murca Fm.Rosablanca Fm.Girón Fm.Macanal Fm.
Rosablanca Fm.
BerriasianCumbre Fm.Cumbre Fm.Los Medios Fm.Guavio Fm.
Tambor Fm.Arcabuco Fm.Cumbre Fm.
Sources

See also

Geology of the Eastern Hills
Geology of the Ocetá Páramo
Geology of the Altiplano Cundiboyacense

References

  1. 1 2 3 4 Montoya & Reyes, 2005, p.24
  2. 1 2 Acosta & Ulloa, 2001, p.41
  3. ↑ Montoya & Reyes, 2005, p.26
  4. ↑ García González et al., 2009, p.218
  5. ↑ Villamil, 2012, p.164
  6. ↑ Villamil, 2012, p.181
  7. ↑ Patarroyo, 2016, p.41
  8. ↑ Blanco et al., 2004, p.26
  9. ↑ 'Yaguarasaurus columbianus' in the Paleobiology Database
  10. ↑ Yaguarasaurus columbianus at Fossilworks.org
  11. ↑ Páramo Fonseca, 2000, p.124
  12. ↑ Plancha 344, 1999
  13. ↑ Plancha 345, 1999
  14. ↑ Plancha 190, 2009
  15. ↑ Plancha 227, 1998
  16. ↑ Plancha 246, 1998

Bibliography

Maps La Frontera Fm. proper

Maps Yaguarasaurus locations

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