Dos Bocas Formation

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).

Dos Bocas Formation
Stratigraphic range: Chattian
(Deseadan)
~
Montañita-Olón locality with outcrops of the Dos Bocas Formation
TypeGeological formation
Unit ofSubibaja Group
UnderliesVillingota Formation
OverliesZapotal Formation
Lithology
PrimarySandstone
Location
Coordinates1.8°S 80.8°W / -1.8; -80.8
Approximate paleocoordinates3.6°S 75.5°W / -3.6; -75.5
RegionSanta Elena Province
Country Ecuador
ExtentProgreso Basin

Description
Stratigraphy of the Montañita-Olón locality

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

The formation has provided fossils of:

See also

References
  1. 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.
  2. 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.
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