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CRESPO DE CABRERA, SANDRA, Corpoven S.A., Puerto La Cruz, Venezuela, and SALLY RADFORD, Royal School of Mines, Imperial College London, London, United Kingdom

ABSTRACT: Miocene Biostratigraphy of Northern Monagas, Eastern Venezuela: Biological Signals of Sea Level and Paleoceanographic Changes in a Foreland Basin

Foraminiferal studies in the Carapita and La Pica formations have provided interesting patterns which could be correlated with paleoceanographic changes brought about by relative sea level changes, among other causes. By their effects on physico-chemical parameters, relative sea level changes will affect the character, composition and distribution of marine biofacies.

Patterns of foraminiferal abundance and diversity and the appearances and extinctions of species have been used to attempt a characterization of system tracts. This is a part of sequence stratigraphy very poorly understood, especially in deep water environments, where abundance peaks occur at several condensed sections within lowstand system tracts in addition to maximum flooding surfaces (Wornardt, 1992).

The Carapita Formation is of Early to Middle Miocene age, zones N4 to N14 (Blow, 1979) and correspond to the upper part of the TB1 and TB2 second order cycles of the Haq et al. chart (1987). It was deposited predominantly in bathyal paleoenvironments,

though neritic conditions have been determined at the base and summit of this formation. It is unconformably overlain by intercalations of sandstones and shales known as La Pica Formation, of Late Miocene age, deposited on environments ranging from inner neritic to continental. This probably correlates with the lower part of the TB3 super cycle.

Both formations were deposited in a foreland basin, formed at the beginning of the Neogene by the southeastward thrusting of the Caribbean plate over the South American continent.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.