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 / 11.96667; -71.37861
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 / 11.96667; -71.37861
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.

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]

Geology of the Eastern Hills

Cesar-Ranchería Basin

Honda Group

Abanico, Castillo, Chota, Loreto, Soncco, Usme Formations

Tinguiririca fauna

• ANH (2010), Guajira Basin - Colombia Open Round 2010 (PDF), ANH, p. 1, retrieved 2017-08-30
• Moreno, F.; Hendy, A.J.W.; Quiroz, L.; Hoyos, N.; Jones, D.S.; Zapata, V.; Zapata, S.; Ballen, G.A.; Cadena, A.L. Cárdenas, J.D. Carrillo Briceño, J.D. Carrillo, D. Delgado Sierra, J. Escobar, J.I. Martínez, C. Martínez, C. Montes, J. Moreno, N. Pérez, R. Sánchez, C. Suárez, M.C. Vallejo Pareja, C. Jaramillo, Edwin (2015), "Revised stratigraphy of Neogene strata in the Cocinetas Basin, La Guajira, Colombia" (PDF), Swiss Journal of Palaeontology, 134: 5–43, Bibcode:2015SwJP..134....5M, doi:10.1007/s13358-015-0071-4, retrieved 2017-08-08{{citation}}: CS1 maint: multiple names: authors list (link)
• Rodríguez, Gabriel; Londoño, Ana Cristina (2002), Mapa geológico del Departamento de La Guajira - 1:250,000, INGEOMINAS, pp. 1–259, retrieved 2017-08-08

• Hendy, Austin J.W.; Jones, Douglas S.; Moreno, Federico; Zapata, Vladimir; Jaramillo, Carlos (2015), "Neogene molluscs, shallow marine paleoenvironments, and chronostratigraphy of the Guajira Peninsula, Colombia" (PDF), Swiss Journal of Palaeontology, 134: 45–75, Bibcode:2015SwJP..134...45H, doi:10.1007/s13358-015-0074-1, retrieved 2017-08-08

• Zuluaga, Carlos A.; Ochoa, Alberto; Muñoz, Carlos A.; Dorado, Camilo E.; Guerrero, Nathalia M.; Martínez, Ana M.; Medina, Paula A.; Ocampo, Edgar F.; Pinilla and Paula A. Ríos, Bibiana P. Rodríguez, Edward A. Salazar, Vladimir L. Zapata, Alejandro (2008), Plancha 3 - Puerto Estrella - 1:100,000, INGEOMINAS, p. 1, retrieved 2017-06-06{{citation}}: CS1 maint: multiple names: authors list (link)
• Zuluaga, Carlos A.; Ochoa, Alberto; Muñoz, Carlos A.; Dorado, Camilo E.; Guerrero, Nathalia M.; Martínez, Ana M.; Medina, Paula A.; Ocampo, Edgar F.; Pinilla and Paula A. Ríos, Bibiana P. Rodríguez, Edward A. Salazar, Vladimir L. Zapata, Alejandro (2008), Plancha 5 - Bahía Portete - 1:100,000, INGEOMINAS, p. 1, retrieved 2017-06-06{{citation}}: CS1 maint: multiple names: authors list (link)
• Zuluaga, Carlos A.; Ochoa, Alberto; Muñoz, Carlos A.; Dorado, Camilo E.; Guerrero, Nathalia M.; Martínez, Ana M.; Medina, Paula A.; Ocampo, Edgar F.; Pinilla and Paula A. Ríos, Bibiana P. Rodríguez, Edward A. Salazar, Vladimir L. Zapata, Alejandro (2008), Plancha 10 - Rancho Grande - 1:100,000, INGEOMINAS, p. 1, retrieved 2017-06-06{{citation}}: CS1 maint: multiple names: authors list (link)
• Zuluaga, Carlos A.; Ochoa, Alberto; Muñoz, Carlos A.; Dorado, Camilo E.; Guerrero, Nathalia M.; Martínez, Ana M.; Medina, Paula A.; Ocampo, Edgar F.; Pinilla and Paula A. Ríos, Bibiana P. Rodríguez, Edward A. Salazar, Vladimir L. Zapata, Alejandro (2008), Plancha 10bis - Rancho Grande - 1:100,000, INGEOMINAS, p. 1, retrieved 2017-06-06{{citation}}: CS1 maint: multiple names: authors list (link)