Cheuquemó Formation

Cenozoic geologic formation

Cheuquemó Formation (Chile)

Cheuquemó Formation (Spanish: Formación Cheuquemó) is a geological formation of sedimentary rock in south-central Chile. The sediments of the formation were deposited during the Late Oligocene and Early Miocene epochs. The formations lower sections are made up of conglomerate, then successions of sandstone, tuff and mudstone rich in organic material follows. The formation indicates that sedimentation occurred in an estuarine (paralic) and other non-marine (continental) environments. It contains fossils of the following genera: Mytilus, Cardium and Turritella. Stratigraphically it overlies the Bahía Mansa Metamorphic Complex and underlies the Miocene Santo Domingo Formation.^[1]

Description

The formation is very similar to the Pupunahue Beds found further north, with the sole difference that the fossil assemblage in both seem to indicate different ages. While Cheuquemó is possibly about 14 million years old (Miocene), the Pupunahue Beds are 35–25 million years old.^[2]

References

^ Elgueta, Sara; Le Roux, Jacobus; Duhart, Paul; McDonough, Michael; Urqueta, Esteban (2000). Estratigrafía y sedimentología de la cuencas terciarias de la Región de Los Lagos (39-41°30'S) (in Spanish). Santiago, Chile: Servicio Nacional de Geología y Minería. pp. 15–16. ISSN 0020-3939.
^ Alfaro, G.; Gantz, E.; Magna, O. (1990). "El yacimiento de carbón Catamutún (La Unión)". Actas. Segundo Simposio sobre el Terciario de Chile (in Spanish). Santiago, Chile: Departamento de Geociencias, Facultad de Ciencias, Universidad de Concepción. pp. 11–28.

Geology of Chile

Terranes

Sedimentary
formations
and groups

Cretaceous	Baños del Flaco Fm. Cerro Colorado Fm. Chacarilla Fm. Chañarcillo Gp. Coihaique Gp. Divisadero Gp. Dorotea Fm. Hornitos Fm. La Liga Fm. Ñirehuao Fm. Punta del Cobre Fm. Purilactis Gp. Quiriquina Fm. Viñita Fm. Way Gp. Zapata Fm.
Jurassic	Chacarilla Fm. Coihaique Gp. Ibáñez Fm. La Liga Fm. La Negra Fm. Nacientes del Biobío Fm. Nacientes del Teno Fm. Pan de Azúcar Fm. Tobífera Fm.
Triassic	Canto del Agua Fm. Choiyoi Gp. Panguipulli Fm. Santa Juana Fm. Tralcán Fm.