PUEBLO VIEJO, Main Sandstone
TERTIARY (Eocene)
State of Zulia, Venezuela
Author of name: Staff of Caribbean Petroleum Co., 1948.
Original reference: Staff of Caribbean Petroleum Co., 1948, p. 525.
See: MICACEOUS, Sandstone and MISOA, Formation.
MICACEOUS, Sandstone
TERTIARY (Eocene)
State of Zulia, Venezuela
Author of name: Staff of Caribbean Petroleum Co., 1948.
Original reference: Staff of Caribbean Petroleum Co., 1948, p. 525.
Original description: ibid.
According to the Staff of Caribbean Petroleum Co. (1948, p. 525) the Eocene in the Bolivar Coast area, State of Zulia, is subdivided into three formations, from top to bottom; Mene Grande formation, Upper Micaceous Sandstone and Lower Micaceous Sandstone. The names Upper and Lower Micaceous Sandstones are not very satisfactory and should be replaced as soon as good type localities and definitions can be agreed on.
The Lower Micaceous Sandstone is monotonous, thick series of dark gray to black, carbonaceous and micaceous sandy shales interbedded with micaceous sandstones. A few outstanding sandstone bodies have been recognized in this part and as an example may be cited the Pueblo Viejo main sandstone which is producing in the Pueblo Viejo field. It is fine to coarsegrained, in places pebbly, quartzitic, and has little porosity and permeability. The Lower Micaceous Sandstone is the approximate equivalent of the Misoa Trujillo formation of the Mene Grande field, and probably corresponds to the Concepción formation from the La Concepción field. The fauna is poor and does not permit a direct age determination. The total thickness of the Lower Micaceous Sandstone in the Bolívar Coastal Fields is unknown, but must amount to more than 10.000 feet.
The Upper Micaceous Sandstone is a series of micaceous shales, sandy shales, and sandstones, which overlies the Lower Micaceous Sandstone with a transition. It corresponds approximately to the Paují formation of the Mene Grande area. Several subdivisions are based on microfaunas.
About 300 feet of oil-impregnated sandstone belonging to the Upper Micaceous Sandstone have been found in the Lagunillas field. The total thickness of the Upper Micaceous Sandstone amounts to about 2,300 feet. It is conformably overlain by the Mene Grande formation.
W. A. Mohler.