CARAPITA, Formation

TERTIARY (Oligocene-?Miocene)

States of Anzoátegui and Monagas, Venezuela

Author of name: H. D. Hedberg, 1937a.

Original reference: H. D. Hedberg, 1937a, p. 2004.

Original description: ibid.

The Carapita formation was named by Hedberg (1937a, p. 2004-2008) from Quebrada Carapita, a tributary of the Rio Querecual in northeastern Anzoátegui, to designate a formation which he subdivided into a lower member consisting of some 2,000 feet of sandstones and sandy and silty shales, and an upper or main member, composed of some 7,000 feet of dark to brownish gray, fissile, foraminiferal shale with common thin seams of clay-ironstone concretions and a few thin beds of fine-grained sandstones similar to those occurring in the lower member.

Hedberg (1937b, p. 661-697) made a detailed description of the foraminifera of the original Carapita formation, dividing it into three foraminiferal "zones". The lower sandy member is included within the Lower and the entire Middle and Upper zones; the age is given as upper Oligocene and possibly lower Miocene in its uppermost part. Franklin (1944, p. 301-319) also described a microfauna from the Carapita to which he assigned a lower Oligocene age. This was disputed and discussed at length by Renz (1948, p. 86-87).

Hedberg and Pyre (1944, p. 22) separated the two members of the original Carapita formation for the purpose of their inclusion into the Santa Inés group. The lower member was named Capaya tongue or member and the upper shale unit, Carapita shale, which grades westward into the Capiricual formation in the Barcelona area.

Hedberg (1950, p. 1201) raised the Carapita shale to formation rank. It thickens eastward at the expense of other units of the Santa Inés group and in the subsurface of northern Monagas, may constitute the bulk of the total thickness of the group. The formation grades into the underlying Capaya formation and is conformably overlain by the Uchirito formation.

Mencher et al. (1951, p. 52) mention the Carapita formation as part of the subsurface section in the Greater Jusepín Area, where it consists of several thousand feet of gray foraminiferal shales (so-called Nodosaria shales), locally interbedded with lenticular sandstones up to 15 feet thick. The formation is truncated below the La Pica unconformity and different stratigraphic horizons of the Carapita are unconformably overlain by the Miocene La Pica formation.

The Carapita formation outcrops along a distance of some 50 kilometers in the northeastern part of Anzoátegui, and is encountered in well sections of northern Monagas.

Cecily Petzall