Gatuncillo Formation

The Gatuncillo Formation (Tgo)[1] is a geologic formation in central Panama. The formation is exposed in the Panama Canal Zone and surrounding areas. It preserves fossils dating back to the Middle to Late Eocene period.[2]

Gatuncillo Formation
Stratigraphic range: Middle-Late Eocene
TypeFormation
UnderliesCaimito, Bohío & Panama Formations
OverliesCretaceous basement
Thickness150–800 m (490–2,620 ft)
Lithology
PrimaryMudstone, siltstone
OtherLimestone, sandstone, conglomerate
Location
Coordinates9.3°N 79.7°W / 9.3; -79.7
Approximate paleocoordinates6.8°N 77.3°W / 6.8; -77.3
RegionPanamá Province
Country Panama
ExtentPanama Basin
Type section
Named forGatuncillo River
Named byThompson
Year defined1944
Gatuncillo Formation (Panama)

Description

The Gatuncillo Formation is the oldest sedimentary unit of the Panama Canal Zone, unconformably resting on Cretaceous basement. The formation was defined as Gatuncillo Shale by Thompson in 1944, who named it after the Gatuncillo River. The estimated thickness ranges from 150 to 800 metres (490 to 2,620 ft).[3]

Though the Gatuncillo consists chiefly of mudstone and siltstone, it includes bentonitic mudstone, sandstone, and limestone, and at the base a conglomerate of variable thickness.[4]

Fossil content

See also

References

  1. Geologic Map, 1980
  2. Gatuncillo Formation at Fossilworks.org
  3. Woodring, 1957, p.13
  4. Woodring, 1957, p.14
  5. Erdei et al., 2018, p.186
  6. Cadena et al., 2012, p.549

Bibliography

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