CAPITANEJO, Sandstone Member

State of Barinas, Venezuela

Author of name: P. Christ, 1927.

Original reference: P. Christ, 1927, p. 406.

See SANTA BARBARA DE "ZAMORA", Beds.

SANTA BARBARA DE "ZAMORA", Beds

TERTIARY

State of Barinas, Venezuela

Author of name: W. G. Argabrite, 1924.

Original reference: R. A. Liddle, 1928, p. 354-55.

Original description: ibid.

As stated by Liddle (1928, p. 354), the Santa Bárbara de "Zamora" beds were originally named the Santa Bárbara beds by Argabrite in 1924 after outcrops near the town of Santa Bárbara in what was then the State of Zamora. Later, Liddle (1946, p. 532) modified the name to Santa Bárbara de "Zamora" beds to avoid confusion with other Santa Bárbara place names in Venezuela although the name of the state had been changed in the meantime to Barinas.

Liddle (1928, p. 354-55) originally described the Santa Bárbara de "Zamora" beds as Quaternary lacustrine or deltaic deposits cropping out in the southeastern foothill belt of the Venezuelan Andes from the Río Chu (Quiu or El Mene) through the type locality of Santa Bárbara, State of Barinas (then Zamora) to San Antonio de Caparo over a distance of 120 kilometers. A local total thickness of 2,500 feet (762 meters) was stated to exist and the basal (lower) part of the beds was described as composed of 2,000 feet (609 meters) of siliceous zones of "infusorial" and "diatomaceous" earth together with "chalks", marls and thin sands with fish-bones and scales accompanying the "infusoria" and "diatoms". The writer's examination of these beds confirmed the presence of siliceous zones but not of diatomaceous earth nor of chalk. The upper part of the beds were stated by Liddle to be composed of poorly consolidated, nearly-pure, white sandstones containing ferruginous concretions.

In Liddle's revised text (1946, p. 532-33) he recognized that the Santa Bárbara de "Zamora" beds were older than Quaternary, as he had stated in 1928, and a possible Miocene and/or Pliocene age was assigned. Also, Liddle recognized that the basal (lower) part of the Santa Bárbara beds contains reworked siliceous material as well as marls and "chalks" with fish remains derived from the middle and upper Cretaceous leached siliceous beds of Kehrer's (1938, p. 49) Santa Bárbara facies, which crop out in the vicinity. Liddle mentioned (1946, p. 533) that where the original and derived material are in contact, it is difficult to distinguish between them.

The upper, white, poorly consolidated sandstone member of Liddle's Santa Bárbara de "Zamora" beds was originally called the Sables of Capitanejo (Sands of Capitanejo) by Christ (1927, p. 406) and included in his Santa Bárbara series which he considered Tertiary in age, but which included both Kehrer's Cretaceous Santa Bárbara facies and Liddle's Tertiary Santa Bárbara de "Zamora" beds.

The sands of Capitanejo (or Capitanejo sandstone member) were named from outcrops on the Río Capitanejo, 30 kilometers northeast of Santa Bárbara. At this locality, a thickness of 30 meters of medium to thickbedded, massive, fine to coarse-grained, white to yellow, to brown, to mottled lavender quartzose sandstone to grit to pebble conglomerate with some grey shale at the base, composes the Capitanejo sandstone member. On the Río El Mene or Quiu, seven kilometers to the northeast, the member is at least 100 meters thick and has stringers and seams of coal up to 30 centimeters thick interbedded with the sandstones and grey silty claystones.

A definite age assignment of the Santa Bárbara de "Zamora" beds is not yet possible. On the Río Curito, located between the Ríos Santa Bàrbara and El Mene, the writer collected samples from the lower siliceous zone of the Santa Bárbara de "Zamora" beds and these samples contained reworked upper Eocene Paují foraminifera, as identified by Dr. J. G. Bursch of the Phillips paleontological laboratory, in addition to reworked fish remains derived from Kehrer's (1938, p. 49) Cretaceous Santa Bárbara facies. It can thus be said that the age of the Santa Bárbara de "Zamora" beds is at least post-middle Eocene Tertiary based on the presence, in the basal part of the beds, of reworked upper Eocene foraminifera which may have begun to have been redeposited in latest upper Eocene times. The Capitanejo sandstone member may correlate with the Oligocene and/or Miocene Palmar formation on the opposite side of the Venezuelan Andes based on marked resemblances in Ethology and stratigraphic position between the two formations.

(See also SANTA BARBARA, Series and SANTA BARBARA, Facies).

H. Alberding