MONTERO, Limestone

TERTIARY (Oligocene)

State of Falcón, Venezuela

Author of name: A. Senn, 1940.

Original reference: A. Senn, 1940, p. 1580.

See PECAYA, Formation.

PECAYA, Formation

TERTIARY (middle Oligocene)

State of Falcón, Venezuela

Author of name: A. Senn, 1932 (private report).

Original reference: A. Senn, 1935, p. 71.

Original description: ibid.

Garner (1926, p. 68) published "Pecaya limestone" for rocks in the hills north of that town; but gave no exact description or location. This name was never generally used and is considered a homonym.

Senn (1935, p. 71) described "Pecaya shales" southwest of the town of Pecaya. These comprise 550 meters of calcareous shales lying below the Pedregoso limestones (see) and above the San Juan de la Vega sandstones. Paraiso shales or "Churuguara beds" (see). In the middle part of the foraminiferal shales is a sandy zone with macrofossils; and at the base are several limestone reefs including the Bocaina reef described by Senn (1935, p. 71) from the gorge of the Río Paraiso southwest of Pecaya. Proper usage would be to make Bocaina a member of the Pecaya formation including the various other disconnected reefs which occur at the same horizon. Senn (1940, p. 1580) shows "Montero limestone" as equivalent to Bocaina. This clearly referred to Montero in the Agua Linda area of eastern Falcón and not "Montero limestone" as used for a younger reef in Buchivacoa, western Falcón. This homonym obviously confused Liddle (1946, p. 406, 409, 419), and it is recommended not to use Montero in either sense.

Senn (1940, p. 1580) shows Pecaya as equivalent to "Pedregal shales" (see); but more recent studies show it equivalent to the Tupure shale (see). Senn (1935) mentions "Globigerina shales" of Eo-Oligocene age, which have since been shown to occur within the Pecaya formation.

The Mitare group (see) includes the Pecaya as one of the principal formations.

G. D. Johnson