Angostura Formation, Ecuador

The Angostura Formation is a Late Miocene (Mayoan to Montehermosan in the SALMA classification) geologic formation of the Borbón Basin in northwestern Ecuador.[1]

Angostura Formation
Stratigraphic range: Late Miocene
~11.6–5.3 Ma
TypeGeological formation
Unit ofSantiago Group
UnderliesOnzole Formation
OverliesViche Formation
Thickness150 m (490 ft)
Coordinates1°00′N 79°36′W / 1.0°N 79.6°W / 1.0; -79.6Coordinates: 1°00′N 79°36′W / 1.0°N 79.6°W / 1.0; -79.6
Approximate paleocoordinates0°36′N 78°00′W / 0.6°N 78.0°W / 0.6; -78.0
RegionEsmeraldas Province
Country Ecuador
ExtentBorbón Basin
Angostura Formation, Ecuador is located in Ecuador
Angostura Formation, Ecuador
Angostura Formation, Ecuador (Ecuador)


The coarse sandstones and beds of conglomerates, about 150 metres (490 ft) in thickness. The formation is resistant to erosion and is largely barren, but at a few places there are lenses or interbeds filled with finely preserved fossils. The formation overlies the Viche Formation, and is overlain by the lower Onzole Formation. The Angostura Formation is time-equivalent with the fossiliferous Gatún Formation of Panama.[1]

Fossil contentEdit

The formation has provided bivalve and gastropod fossils.[1]

See alsoEdit


Further readingEdit