TINAJITAS, Member

See: TINAJITAS, Formation.

TINAJITAS, Formation

TERTIARY (upper Eocene)

State of Anzoátegui, Venezuela

Author of name: H. D. Hedberg and A. Pyre, 1944.

Original reference: H. D. Hedberg and A. Pyre, 1944, p. 15-21.

Original description: ibid.

Hedberg and Pyre (1944, p. 15) originally introduced this term to designate the lower member of the Merecure formation, with its type locality in the Quebrada Tinajitas and along the Puerto La Cruz-Oficina highway just east of Barcelona. Here, it is at least 650 feet thick and consists of orbitoid-algal reef limestone which change laterally to discontinuous and thin limestone lenses. These limestones immediately overlie Santa Anita siltstones on certain hills in the vicinity of Puerto La Cruz. Above the orbitoid limestones, the remainder of theTinajitas member consists of interbedded lavender-gray quartzitic sandstone, gray and greenishgray slightly glauconitic sandstone and siltstone, and gray silty and locally foraminiferal shale. Southeastward, the unit grades laterally into the Los Jabillos sandstone and in the vicinity of Naricual the two facies distinctly interfinger.

Hedberg (1950, p. 1196-1197) raised the Merecure formation to group rank and its Tinajitas, Los Jabillos and Naricual members to formations. He draws attention to the possibility that in the ríos Querecual, Areo and others, where the Los Jabillos sandstone is well developed, there is.generally between this unit and the underlying Caratas formation, a small interval of calcareous sediments with orbitoids, nummulites, calcareous algae, Tubulostium, Oligopygus, etc., which can be assigned to the Tinajitas formation.

The stratigraphic relation between the Tinajitas formation and the underlying Santa Anita group is not very clear. According to Hedberg and Pyre (1944, p. 17), it is unconformable with an intervening hiatus in the Barcelona area; toward the east the indication of unconformity becomes less distinct, and in the ríos Aragua and Orégano it appears to be of transitional character. In northwestern Anzoátegui and northern Guárico the Tinajitas formation is generally found in contact with Guayuta group sediments (Hedberg, 1950, p. 1197).

In the Quiriquire field, reefal limestones and sandstones of the Eocene Mundo Nuevo formation (Borger, 1952, p. 2302-2303) appear to correlate (with the Tinajitas formation. The Tinajitas formation is also referred to by Liddle (1946, p. 309, 337, correlation chart) as El Picacho and Cerro Peñas Blancas (Peñas Blancas limestone of Senn, 1940, p. 1580) horizons and La Pedrera limestone, but all these terms are now obsolete.

Paleontological evidence (large and small foraminifera, echinoids and mollusks) indicates an upper Eocene age for the Tinajitas formation (Hedberg and Pyre, 1944, p. 18-19).

Gustavo Feo-Codecido