Siamaná Formation

Siamaná Formation
Siamaná Formation
Stratigraphic range: Mid-Late Oligocene; ~28–23 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Cocinetas Basin
Underlies	Uitpa Formation
Overlies	Macarao Formation
Thickness	430 m (1,410 ft)
Lithology
Primary	Conglomerate
Other	Limestone
Location
Coordinates	11°58′00″N 71°22′43″W / 11.96667°N 71.37861°W
Region	La Guajira; Caribbean region
Country	Colombia
Type section
Named for	Siamaná
Named by	Renz
Location	Uribia
Year defined	1960
Coordinates	11°58′00″N 71°22′43″W / 11.96667°N 71.37861°W
Region	La Guajira
Country	Colombia
	; Type locality of the formation in La Guajira

The Siamaná Formation (Spanish: Formación Siamaná, E3s) is a fossiliferous geological formation of the Cocinetas Basin in the northernmost department of La Guajira. The formation consists of conglomerates and limestones. The Siamaná Formation dates to the Paleogene period; Middle to Late Oligocene epoch, corresponding to the Deseadan in the SALMA classification.

Etymology

The formation was defined by Renz in 1960 and named after the village of Siamaná.^[1]

The Siamaná Formation consists of conglomerates and thick carbonates.^[2]

The Siamaná Formation, with a maximum thickness of 430 metres (1,410 ft), overlies the Macarao Formation and is overlain by the Uitpa Formation. The age has been estimated to be Middle to Late Oligocene, corresponding to the Deseadan in the SALMA classification. The depositional environment has been interpreted as shallow marine.^[3]

The Siamaná Formation is a reservoir and seal rock formation in the Guajira Basin.^[4]

Group	Fossils	Notes
Invertebrates	Mimachlamys canalis, Ostrea sp.	^[5]