COLON, Limestone

See COGOLLO, Formation.

COGOLLO, Formation

CRETACEOUS (Aptian to Cenomanian)

State of Zulia, Venezuela

Author of name: A. H. Garner, 1926.

Original reference: A. H. Garner, 1926, p. 679

Original description: ibid.

The term Cogollo was first published by A. H. Garner (Río Cogollo limestone) for the gray massive crystalline fossiliferous limestone that underlies the La Luna formation on Río Cogollo, Sierra de Perijá, Zulia (Garner, 1926, p. 678-679).

R. A. Liddle and others used the name Cogollo formation or Cogollo limestone for the complex of gray hard massive limestones and interbedded gray to black shales which are widely distributed in Western Venezuela and which occupy the stratigráphic interval between the clastic deposits of the basal Cretaceous (Río Negro formation) and the Upper Cretaceous La Luna formation (Liddle, 1928; Hedberg, 1931; Hedberg and Sass, 1937; Sutton, 1946, etc.). The names Cogollo formation or Cogollo limestone have unfortunately been used by some authors in a very restricted sense, viz. to represent only the uppermost part of the Cogollo Group, i e., the Capacho formation of the Andes and the Capacho-Maraca formations of the Sierra de Perijá (Kehrer, 1937, p. 54; Tomalin, 1938, p. 12; Notestein et al., 1944, p. 1178; Liddle, 1946, pars; Staff of Caribbean Petroleum Company, 1948, p. 612; Mencher et al., 1953, p. 730). J. E. Smith (1951), on the other hand, includes the entire Cretaceous of pre-La Luna age in the Cogollo formation (=Río Negro formation + Cogollo Group); this use of the term Cogollo is also accepted by the Shell Group in the Maracaibo-Mara region (Mencher et al., 1953, p. 723). J. E. Smith's term Cogollo limestone equals the Cogollo group; his lower Cogollo is lower Apón, his "Middle Cogollo Shale Break" is middle Apón, his middle Cogollo is upper Apón, and his upper Cogollo is Lisure-Capacho-Maraca (see APON, LISURE, CAPACHO, and MARACA Formations).

In the original type section on Río Cogollo, Sierra de Perijá, the top beds (Maraca formation) and the base of the Cogollo formation are cut out by faulting (Rod, 1950, see Rod and Maync, 1954, p. 200 etc.). On account of this incomplete section at the type locality and of the considerable stratigraphic span attributed to the Cogollo formation, the popular name Cogollo is retained as a group term (Sutton, 1946, p. 1641).

The comprehensive name Cogollo formation (or Cogollo limestone) is replaced by a group of minor stratigraphic units, viz. (from bottom to top) the Apón, Aguardiente - Lisure, and Capacho - Maraca formations (Sutton, 1946, p. 1630, 1642, etc.; Rod and Maync, 1954, p. 202 etc.).

Wolf Maync