The Siamaná Formation ( es, Formación Siamaná, E3s) is a fossiliferous

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 Cocinetas Basin in the northernmost

department Department may refer to: * Departmentalization, division of a larger organization into parts with specific responsibility Government and military *Department (administrative division), a geographical and administrative division within a country, ...

of La Guajira. The formation consists of conglomerates 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 ...

s. The Siamaná Formation dates to the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

period; Middle to Late Oligocene epoch, corresponding to the

Deseadan The Deseadan ( es, Deseadense) age is a period of geologic time (29.0–21.0 Ma) within the Oligocene epoch of the Paleogene to the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It fo ...

in the

SALMA The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as a ...

classification.

Etymology

The formation was defined by Renz in 1960 and named after the village of Siamaná.Moreno et al., 2015, p.7

Description

Lithologies

The Siamaná Formation consists of conglomerates and thick

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...

s.Hendy et al., 2015, p.47

Stratigraphy and depositional environment

The Siamaná Formation, with a maximum thickness of , overlies the

Macarao Formation The Macarao Formation ( es, Formación Macarao, E2m) is a formation (geology), geological formation of the Cocinetas Basin in the northernmost Colombian departments of Colombia, department of La Guajira Department, La Guajira. The formation consis ...

and is overlain by the

Uitpa Formation The Uitpa Formation ( es, Formación Uitpa, E3u) is a fossiliferous geological formation of the Cocinetas Basin in the northernmost department of La Guajira. The formation consists of calcareous mudstones interbedded with lithic sandstones. The ...

. The age has been estimated to be Middle to Late Oligocene, corresponding to the

in the

classification. The depositional environment has been interpreted as shallow marine.Rodríguez & Londoño, 2002, p.132

Petroleum geology

The Siamaná Formation is a

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

and

seal rock A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presenc ...

formation in the

Guajira Basin Guajira may refer to: * Guajira Peninsula, a peninsula in the northernmost part of South America shared by Colombia and Venezuela * Guajiro people (Wayuu), a South American ethnic group inhabiting northeastern Colombia and northwestern Venezuela * ...

.ANH, 2010

Fossil content

References

Bibliography

Local geology

* * *

Paleontology

Maps

* * * * {{DEFAULTSORT:Siamana Formation Geologic formations of Colombia Paleogene Colombia Oligocene Series of South America Chattian Stage Deseadan Conglomerate formations Limestone formations Shallow marine deposits Reservoir rock formations Seal rock formations Fossiliferous stratigraphic units of South America Paleontology in Colombia Geography of La Guajira Department