ANALISIS TECTONO-SEDIMENTARIO DE LA FORMACION PAMPATAR (EOCENO MEDIO), ISLA DE MARGARITA, VENEZUELA

Resumen

The Pampatar Fonnation (Eocene) of Margarita Island, Venezuela, consists mainly of interbedded sandstones and shales, with some conglomerates. These sediments are interpreted as turbidites deposited in submarine canyons and fans. The conglomerates represent canyon and inner-fan-channel deposits. The rest of the succession represents the entire range of fan environments, from inner to outer fan. Triangular diagrams of sandstone composition (100 samples) elucidate the tectonic setting. Most samples plot in the "recycled orogenic" field of the Q-F-L triangle, while the Qm-F-Lt diagram shows a wider dispersion, including "transitional recycled", "mixed zone", and "magmatic arc". This association is interpreted in terms of uplift and erosion of a subduction-accretion complex, which supplied most of the sediments to the Pampatar Formation (recycled orogen component), with an additional, minor contribution from a dissected and transitional magmatic arc.

KEY WORDS. Margarita Island. Pampatar Formation. Eocene. Turbidites. Sedimentary petrography. Triangular diagrams.