Dos Bocas Formation
| Dos Bocas Formation | |
|---|---|
| Stratigraphic range: Chattian (Deseadan) ~ | |
 Montañita-Olón locality with outcrops of the Dos Bocas Formation | |
| Type | Geological formation |
| Unit of | Subibaja Group |
| Underlies | Villingota Formation |
| Overlies | Zapotal Formation |
| Lithology | |
| Primary | Sandstone |
| Location | |
| Coordinates | 1°48′S 80°48′W / 1.8°S 80.8°W |
| Approximate paleocoordinates | 3°36′S 75°30′W / 3.6°S 75.5°W |
| Region | Santa Elena Province |
| Country |  Ecuador |
| Extent | Progreso Basin |
The Dos Bocas Formation is a sedimentary geological formation of the Progreso Basin in southwestern Ecuador. It is dated to the Chattian, about 26 to 24 Ma, (Deseadan in the SALMA classification).
Description
[edit]
The formation comprises moderately-sorted, fine to medium sandstones with angular quartz-feldspathic clasts. Conspicuous rounded green grains are probably glauconite, but berthierine cannot be dismissed. The matrix is micritic and volcanogenic, possibly bentonitic. The formation was deposited in an estuarine to mid shelf environment. Fossils of sharks, turtles and the tropical dolphin Urkudelphis were recovered from the formation.[1][2]
Fossil content
[edit]The formation has provided fossils of:
See also
[edit]- List of fossiliferous stratigraphic units in Ecuador
- Bahía Inglesa Formation
- Coquimbo Formation
- Pisco Formation
References
[edit]- ^ Tanaka, Y.; Abella, J.; Aguirre-Fernández, G.; Gregori, M.; Fordyce, E. R. (2017). "A new tropical Oligocene dolphin from Montañita/Olón, Santa Elena, Ecuador". PLOS ONE. 12 (12): e0188380. Bibcode:2017PLoSO..1288380T. doi:10.1371/journal.pone.0188380. PMC 5737981. PMID 29261688.
- ^ Carrillo-Briceño, J. D.; Villafaña, J. A.; De Gracia, C.; Flores-Alcívar, F. F.; Kindlimann, R.; Abella, J. (2020). "Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene–Miocene boundary of Ecuador". PeerJ. 8: e9051. doi:10.7717/peerj.9051. PMC 7195833. PMID 32391203.