The Fómeque Formation (, Kif) 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

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 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 organic shale formation dates to the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

period;

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...

to Late Aptian epochs and has a maximum thickness of .

Etymology

The formation was defined and named in 1957 by Hubach after Fómeque, Cundinamarca.Acosta & Ulloa, 2002, p.52

Description

Lithologies

The Fómeque Formation has a maximum thickness of , and is characterised by a sequence of pyritic organic shales, with

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

s and

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 ...

banks intercalated in the formation. The Fómeque Formation contains high values of TOC.Acosta & Ulloa, 2002, p.53 Fossils of '' Acarthohoplites sp.'', '' Melchionites sp.'', '' Nicklesia sp.'', '' Olcostephanus sp.'', '' Pulchellia sp.'' have been found in the formation.Caicedo et al., 2002, p.29

Stratigraphy and depositional environment

The Fómeque Formation overlies the Las Juntas Formation and is overlain by the

Une Formation The Une Formation (, Kiu) is a formation (geology), geological formation of the Altiplano Cundiboyacense, Cordillera Oriental (Colombia), Eastern Ranges of the Colombian Andes. The predominantly sandstone formation dates to the Cretaceous, Middle ...

. The age has been estimated to be

to Late Aptian. Stratigraphically, the formation is time equivalent with the Mercedes Formation. The formation has been deposited in a shallow marine environment.

Outcrops

The Fómeque Formation is apart from its type locality, found in other parts of the Eastern Ranges.

Regional correlations

Notes

References

Bibliography

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Maps

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External links

* {{DEFAULTSORT:Fomeque Formation Geologic formations of Colombia Cretaceous Colombia Lower Cretaceous Series of South America Barremian Stage Aptian Stage Shale formations Shallow marine deposits Source rock formations Mining in Colombia Formations Geography of Cundinamarca Department Geography of Boyacá Department