Jama Formation

The Jama Formation is a Pliocene to Early Pleistocene (Montehermosan to Ensenadan in the SALMA classification) geological formation in Ecuador. The claystones and sandstones were deposited in a coastal environment. The age of the Jama Formation is constrained by ⁴⁰Ar/³⁹Ar dating of tephra beds.^[1] The formation is correlated to the Charco Azul Formation of western Panama and southeastern Costa Rica.^[2]

Jama Formation
Stratigraphic range: Pliocene-Early Pleistocene (Montehermosan-Ensenadan) ~5.3–0.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Lithology
Primary	Claystone, sandstone
Location
Coordinates	0.2°S 80.3°W / -0.2; -80.3
Approximate paleocoordinates	0.3°S 79.9°W / -0.3; -79.9
Region	Manabí Province
Country	Ecuador
Type section
Named for	Jama
Jama Formation (Ecuador)

Subdivision

The formation is subdivided in, from top to base:

• El Matal Member (60 metres (200 ft), fluvial)
• Punta Ballena Member (lower shoreface)
• Punta Pasa Borracho Member (20 metres (66 ft), marine)

Fossil content

The formation has provided bivalve, gastropod and scaphopod fossils.

See also

• Earth sciences portal
• Paleontology portal
• Ecuador portal

• List of fossiliferous stratigraphic units in Ecuador