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 <sup>40</sup>Ar/<sup>39</sup>Ar dating of tephra beds. The formation is correlated to the Charco Azul Formation of western Panama and southeastern Costa Rica.
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
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