NECESIDAD, Formation

TERTIARY-QUATERNARY

State of Zulia, Venezuela

Author of name: H. F. Nash, 1919 (private report).

Original reference: F. B. Notestein et al., 1944, p. 1204.

Original description: ibid.

This formation is named from Playa Necesidad on the Río de Oro, a short distance above its confluence with thg Río Catatumbo. According to Notestein et al. (1944, p. 1204) no type section has been or can be measured as the formation is poorly exposed and its top is not known. At Playa Necesidad the formation consists of bright-colored red and blue clays, interbedded with coarse-grained sandstones which grade into conglomerates with pebbles up to 2 centimeters in diameter. Southeast of the Río Catatumbo the formation consists of a thick series of fine to coarse-grained massive cross-bedded, friable buff to yellow sandstones and interbedded claystones. According to Notestein et al. (1944, p. 1205) these beds may not be the exact equivalent of those at Playa Necesidad.

The total thickness is unknown, at Playa Necesidad there may be as much as 50 meters of the formation. Near Río de Oro airport, the formation rests horizontally against steeply dipping Guayabo. The formation is of nonmarine origin. Its age is presumably Pliocene or Pleistocene.

According to Notestein et al. (1944, p. 1205) no correlation has been attempted as its relations, even locally, are very dubious. The Necesidad formation crops out in the northeastern part of the Barco concession in Colombia and the adjacent part of Venezuela. See also Sutton (1946, p. 1710).

W. A. Mohler