Abstract: Facies, Age and Sedimentary Environment of the El Cantil, Chimana and Ouerecual Formations, Pertigalete, Northeastern Anzoategui, Venezuela

Francia Antonia Galea-Alvarez, Miriam Coriano, Amarilis Aponte

Field and microfacies studies allowed us to recognize the upper Punceres Member of the El Cantil Formation at the Vencemos quarry, Pertigalete. A lower Orbitolinid interval, mudstones/grainstones, is separated by a wedging brownish-pink dolomite from upper bioclastic, mainly Rudist-bearing, packstones-wackestones. A sea level drop is suggested in the middle of the formation, but the section belongs to a transgressive highstand event initiated in the late Aptian. Several faults produced a thin breccia at the boundary between El Cantil and the Chimana Formations.

Coarse-grained sandstones at the bottom, and fine-grained bioturbated sandstones to the top, bound a mixture of molluskfragments packstones-grainstones, and silty shales, characteristics of the Chimana Formation. The Chimana beds are interpreted as coastal lowstand to the base, middle transgressive neritic shales and nearshore highstand deposit to the top. The Chimana and the Querecual Formations contact corresponds with the 98 m.y. sequence boundary.

The transgressive lowermost shales of the Querecual Formation are soft, dark gray, and laminated, and are followed by black, microlaminated marls and shales. Plankontic foraminifers led us to determined a late Albian-early Turonian age. The sedimentary environment is interpreted as outer neritic and anoxic.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela