TOMON, Sandstones

LOWER CRETACEOUS

State of Táchira, Venezuela

Author of name: L. Kehrer, 1937.

Original reference: L. Kehrer, 1937, p. 54.

Original description: ibid.

The terms Tomón sandstones, Tomón group, or Tomón series were introduced and arbitrarily applied to the thick sandy and conglomeratic sediments of the Lower Cretaceous which rest unconformably on the pre-Cretaceous and exhibit a transitional contact with the overlying "Cogollo limestone" (the term "Cogollo limestone" is used by L. Kehrer et al. in a very restricted sense for the uppermost limestone unit of the Cogollo group in the Venezuelan Andes; see Capacho, Cogollo, Maraca, and Río Negro formations).

W. G. C. Tomalin uses the name Tomón formation for the same sedimentary interval (Tomalin, 1938, p. 12).

Type locality: Alto de Tomón, between Monte Carmelo and Mendoza Fría, District Escuque, Trujillo.

The term Tomón facies is used by C. González de Juana for the basal clastic phase of the Urgonian cycle which is followed by his Cogollo facies (González de Juana, 1951, p. 197).

By raising the Cogollo formation of authors to group rank and by introducing the names Apón, Aguardiente, and Capacho formations in the sequence of Zulia, F. A. Sutton (1946) avoids the term Tomón formation.

In view of the facts, that the beds at the type locality of the Tomón partly belong to the Eocene; that the stratigraphic relationship between the Tomdn beds and the Río Negro formation-Cogollo Group is evident; and that the Tomón beds are the exact equivalent of the Uribante formation of the Barco Concession and Táchira, the term Tomón is better eliminated (Rod and Maync, 1954, p. 219).

Wolf Maync