Coquimbo Formation

Coquimbo Formation
Stratigraphic range: MioceneMid Pleistocene
~23–1.2 Ma
Type Geological formation
Underlies Alluvium
Overlies Liman Formation
Thickness 63 m (207 ft)
Lithology
Primary Conglomerate, sandstone, siltstone, shale and coquina
Other Clay lenses, terra rossa
Location
Coordinates 30°20′21″S 71°32′03″W / 30.33917°S 71.53417°W / -30.33917; -71.53417Coordinates: 30°20′21″S 71°32′03″W / 30.33917°S 71.53417°W / -30.33917; -71.53417
Approximate paleocoordinates 30°06′S 70°18′W / 30.1°S 70.3°W / -30.1; -70.3
Region Coquimbo Region
Country  Chile
Extent Tongoy Bay
Type section
Named for Coquimbo

Coquimbo Formation (Spanish: Formación Coquimbo) is a Miocene to Middle Pleistocene sedimentary formation located in Coquimbo Region in Norte Chico, Chile. The lowermost unit belongs to the lower Miocene, with the third-deepest unit dated at 11.9 ± 1.0 Ma. The uppermost unit of the formation is estimated at 1.2 Ma. In the area of Tongoy, the Coquimbo Formation was deposited in an ancient bay that was formed in a graben or half-graben, with a normal fault dipping east. Sea level changes during the Holocene have caused erosion to cut several marine terraces into the formation.[1]

Fossil content

The following fossils have been found in the formation:

SALMA Group Fossils Notes
MontehermosanMammalsDelphinus domeykoi, Megaptera hubachi, Pliopontos sp., ?Squalodon sp., Balaenidae indet.
Birdscf. Palaeospheniscus sp., Spheniscus sp., Diomedeidae indet., Spheniscidae indet.
FishCarcharodon carcharias
MayoanCosmopolitodus hastalis

See also

References

  1. Le Roux, J.P.; Olivares, Danisa M.; Nielsen, Sven N.; Smith, Norman D.; Middleton, Heather; Fenner, Juliane; Ishman, Scott E. (2006). "Bay sedimentation as controlled by regional crustal behaviour, local tectonics and eustatic sea-level changes: Coquimbo Formation (Miocene–Pliocene), Bay of Tongoy, central Chile" (PDF). Sedimentary Geology. 184 (1–2): 133–153. Retrieved 11 April 2016.
  2. Coquimbo at Fossilworks.org
  3. Bahia de Guayacan at Fossilworks.org
  4. Bahia Herradura at Fossilworks.org
  5. La Cantera at Fossilworks.org
  6. Chanaral de Aceituno at Fossilworks.org
  7. Tongoy area Unit 11 at Fossilworks.org
  8. Tongoy area Unit 4 at Fossilworks.org

Further reading

  • C. Acosta Hospitaleche, J. Canto, and C. P. Tambussi. 2006. Pingüinos (Aves, Spheniscidae) en Coquimbo (Mioceno Medio-Plioceno Tardio), Chile y su vinculación con las corrientes oceánicas. Revista Española de Paleontología 21(1):115-122
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