PASO DIABLO, Formation

TERTIARY (lower and middle Eocene)

State of Zulia, Venezuela

Author of name: H. D. Hedberg, 1929 (private report).

Original reference: H. D. Hedberg and L. C. Sass, 1937, p. 90-91.

Original description: ibid.

The formation name was introduced by Hedberg for the section exposed in the Caño Paso del Diablo in the northwestern part of the Mara District. The measured section of the type locality extends upstream from the Pozo de Barqueta through 2800 feet of section; a maximum thickness of 3350 feet is exposed on Río Guasare.

Hedberg and Sass (1937, p. 91) described the formation as consisting of over a third of dark gray shale but characterized by massive, variably calcareous, light gray, thick-bedded sandstones and numerous beds of subbituminous to bituminous coal. Coals are thick and abundant in the lower 1500 feet of section, while in the upper part they are thin and infrequent. Massive sandstones occur throughout but are well developed at the top and bottom of the formation, becoming increasingly calcareous toward the base, where there is a transition into the sandy limestones and limestones of the underlying Guasare formation.

The Paso Diablo formation conformably overlies the Guasare formation and conformably underlies the Mostrencos formation. Fossils are rare in the formation and those found have been of little stratigraphic value; the few foraminifera present belong to arenaceous genera: Ammobaculites, Haplophragmeides, Trochammina and Textularia. The Eocene age is evident from its stratigraphic position and Hedberg and Sass believe that it are presents some part of lower and middle Eocene time.

The formation is equivalent to part of the Third Coal Series of Liddle and others (Hedberg and Sass, 1937, p. 91) and to the Misoa and Trujillo formations (Schaub, 1948, p. 226; González de Juana, 1951, p. 282, 285). Sutton (1946, p. 1677) correlates the upper Paso Diablo with the Potreritos, believing an upper Eocene age and placing a hiatus between the Paso Diablo and the Guasare formations.

Gordon A. Young