Gatuncillo Formation

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Gatuncillo Formation
Stratigraphic range: Middle-Late Eocene
Type Formation
Underlies Caimito, Bohío & Panama Formations
OverliesCretaceous basement
Thickness150–800 m (490–2,620 ft)
Lithology
Primary Mudstone, siltstone
Other Limestone, sandstone, conglomerate
Location
Coordinates 9°18′N79°42′W / 9.3°N 79.7°W / 9.3; -79.7
Approximate paleocoordinates 6°48′N77°18′W / 6.8°N 77.3°W / 6.8; -77.3
Region Panamá Province
Country Panama
Extent Panama Basin
Type section
Named for Gatuncillo River
Named byThompson
Year defined1944
Panama relief location map.jpg
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Gatuncillo Formation (Panama)

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]

Contents

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