Jama Formation

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

↓
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°12′S 80°18′W / 0.2°S 80.3°WCoordinates: 0°12′S 80°18′W / 0.2°S 80.3°W
Approximate paleocoordinates	0°18′S 79°54′W / 0.3°S 79.9°W
Region	Manabí Province
Country	Ecuador
Type section
Named for	Jama
	Jama Formation (Ecuador)

The Jama Formation is a Pliocene to Early Pleistocene (Montehermosan to Ensenadan in the SALMA classification) geologic formation in Ecuador. The claystones and sandstones were deposited in an 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]

Subdivision[]

The formation is subdivided in, from top to base:

The formation has provided bivalve, gastropod and scaphopod fossils.

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