CODORE, Formation

TERTIARY (upper Miocene)

State of Falcón, Venezuela

Author of name: S. H. Williston, 1922 (private report).

Original reference: F. Hodson, 1926, p. 173.

Original description: ibid.

The term "Codore" has been used in the past by several writers, with different spellings and different meanings.

Hodson (1926, p. 173) described the "Codera formation" (misspelling) as consisting of variegated clays and sands. The type locality he cited as just south of "Codera de Dentro" (correct: Codore Adentro), District of Democracia, State of Falcón.

Senn (1935, correlation chart) showed the "Upper Cadore formation" (mispelling) in the Pliocene of central Falcón, resting unconformably on the La Vela formation.

Senn (1940, p. 1580) placed the "Upper Cadore formation" (misspelling) in the Pliocene of central Falcón and gave below the unit's name the "San Gregorio horizon" in parentheses. The "Upper Cadore" is shown to rest on the La Vela formation unconformably.

Liddle (1946, correlation chart) showed the "Upper Codore" in the basal Pliocene of central Falcón. This "Upper Codore" is shown to include the following three units: Puerto Cumarebo, El Veral, and San Gregorio. On the chart the "Upper Codore" is unconformably overlain by the "Coro conglomerate" and rests unconformably on the "La Vela or (Lower Codore)". This "Lower Codore" is given in the upper Miocene of central Falcón on the chart, together with "Los Algodones".

Mencher et al. (1951, correlation chart) assigned the "Codore formation" to the lower Pliocene and the uppermost Miocene of central Falcón. Their usage seems to have restricted the "Codore" mainly to the "Upper Codore" of Liddle (1946, correlation chart) and to the "Upper Cadore" of Senn (1935; 1940, correlation charts). Mencher et al. showed the "Codore" resting unconformably on the Urumaco formation and unconformably overlain by Holocene alluvial deposits. Information taken from private reports indicates that a group of geologists has redefined the term as Codore formation, restricting it to upper Miocene sediments because the type locality at Codore Adentro is in the upper Miocene Algodones and is separated from the Pliocene sediments by an unconformity. Following this usage, the "Codore formation" of Mencher et al. (1951, correlation chart) would be synonymous with the combined San Gregorio and Río Seco formations, or with the San Gregorio formation if the Río Seco is included in the San Gregorio as its upper member Then the "Lower Codore" of Liddle (1946, correlation chart) would be more or less the same as the Codore of the present usage. A number of other geologists consider the Codore as a group including the Algodones, Chiguaje, and "Taparito" formations, all in the upper Miocene. The group of geologists mentioned first prefers to include the Algodones, Chiguaje, and "Taparito" as members in the Codore formation, mainly for the reason that it becomes difficult to distinguish the Algodones from the "Taparito" wherever the comparatively thin Chiguaje is not exposed. Both the Codore formation and the Codore group of this usage cover exactly the same stratigraphic section, the only difference being the stratigraphic rank. The "La Puerta beds and formation" of Liddle (1928, p. 320-321 and 1946, p. 496-508), the "Upper Section" of the "La Puerta Series" of Halse (1937, p. 177-178) and the "Upper La Puerta "sediments" of González de Juana (1938,p. 130-133) are all known to be synonymous with the Codore of the present above mentioned usage. Further information taken from private reports indicates that the type section of the Codore, following the usage given in this paragraph, is exposed on the Río Codore beginning at the top of the uppermost fossiliferous bed of the Urumaco formation cropping out at El Jebe, 3.5 kilometers north of El Mamón and continuing northward about 4 kilometers along the river. The unit consists of interbedded clays, silts, sandstones, and fossiliferous limestones. For more details on the Ethology see the Algodones, Chiguaje, and "Taparito" formations. The thickness of the Codore at its type section is 757 meters. The contact of the Codore formation (present usage) with the underlying Urumaco formation is conformable. Its upper contact with the San Gregorio formation is unconformable. The Codore extends through northcentral and northwestern Falcón.

Leo Weingeist