CERRO MISION, Shales

See CERRO MISION, Formation.

CERRO MISION, Formation

TERTIARY (upper Eoceno)

State of Falcón, Venezuela

Author of name: A Senn, 1935.

Original reference: A. Senn, 1935, p. 58.

Original description: ibid.

A. Senn (1935, p. 58) introduced the name Cerro Misión shales for a sequence of upper Eocene shales in Eastern Falcón with type locality at Cerro de la Misión, District of Silva. The shales are rich in small foraminifra among which Bulimina jacksonensis Cushman and Hanthenina sp. are mentioned, and the fauna idicates a correlation with the Paují shales of the Maracaibo Basin. The base of the Cerro Misión shales is not exposed, and according to Senn (1935, Taf. VIII) they are unconformably overlain by the upper Eocene Cerro Campana beds or Cerro Campana limestone, which Senn (1940, p. 1580) is inclined to correlate with the basal part of the Aguanegra formation (misspelled Aguanegra formation). Liddle (1946, p. 299) mentions for the first time the Cerro Misión as a formation, but later refers to it predominantly as Cerro Misión shales.

H. H. Renz (1948, p. 8) states that the Tertiary sedimentary section in Eastern Falcón begins, so far as is known, with the upper Eocene Cerro Misión formation (or other equivalent formations) which seems to lie transgressively on older formations of unknown ages. "...The Cerro Misión formation consists of more than 400 meters of dark gray calcareous shales which crop out in the south rim of the Eastern Falcón Basin, north of the Caribbean Coastal Range. It has been penetrated by several wells at Riecito and El Mene de Acosta..." In the Guacharaca uplift (10 kilometers north-northwest of the Pozón trigonometric station) the formation contains orbitoidal limestone lenticles of the Cerro Campana limestone type. (Cerro Campana lies about 7 kilometers north-northwest of El Mene de Acosta). The Cerro Misión formation grades upwards conformably into the Guacharaca formation. Renz (1948, p. 30) mentions some typical upper Eocene small foraminifera obtained from the Cerro Misión formation of El Mene well no. 47, between 1,960 and 2,000 feet.

H. H. Renz