Abstract

Late middle Miocene to middle or late Pliocene benthic foraminifera from north-central Falcón State, northwestern Venezuela, were used in determinations of the marine paleoenvironments of the Urumaco, Codore, Caujarao, La Vela and San Gregorio formations. From 121 collected samples, 31 that included a total of 126 taxa were applied to paleoenvironmental interpretations, and 20 well-preserved foraminiferal samples were analyzed with cluster analysis. In the Urumaco region, the upper middle to upper Miocene Urumaco Formation, which alternates among continental, marginal marine, and marine facies, was predominantly inner shelf, and the taxa and very low diversities suggest highly variable, low-salinity conditions. Foraminifera of the upper Miocene–middle Pliocene Chiguaje Member of the overlying Codore Formation indicate a deepening from inner to deeper-middle shelf. The middle to upper Pliocene San Gregorio Formation varies from estuarine in the lower Vergel Member to inner shelf in the overlying Cocuiza Member. In the Coro–La Vela region to the northeast, paleobathymetries are deeper, fluctuating from middle- to outer-neritic depths in the upper Miocene Taratara Member of the Caujarao Formation, and middle-neritic depths in the conformably overlying upper Miocene, basal part of the La Vela Formation. The relatively stable water depths of the Caujarao and lower La Vela formations support deposition on a stable marine platform. Overall, the shallower facies in the west and deeper facies in the east agree with the interpretation of an eastward progression of inversion of the Falcón basin from Miocene to Pliocene time. The middle Miocene–Pliocene shelf sequences of Falcón are compared to other formations of Venezuela and Colombia with similar paleoenvironments.

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