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.Jama Formation at Fossilworks.org The formation is correlated to the Charco Azul Formation of western Panama and southeastern Costa Rica.Charco Azul Formation at Fossilworks.org
Subdivision The formation is subdivided in, from top to base: El Matal Member (, fluvial) Punta Ballena Member (lower shoreface) Punta Pasa Borracho Member (, marine)
Fossil content The formation has provided bivalve, gastropod and scaphopod fossils.
See also
List of fossiliferous stratigraphic units in Ecuador
References
Further reading G. Cantalamessa, C. Di Celma, and L. Ragaini. 2005. Sequence stratigraphy of the Punta Ballena Member of the Jama Formation (Early Pleistocene, Ecuador): insights from integrated sedimentologic, taphonomic and paleoecologic analysis of molluscan shell concentrations. Palaeogeography, Palaeoclimatology, Palaeoecology 216:1-25 H. A. Pilsbry and A.A. Olsson. 1941. A Pliocene fauna from Western Ecuador. Proceedings of the Natural Sciences of Philadelphia 93:1-79