--> Abstract: The Foz Do Amazonas Basin — From Updated Geological Evolution of a Complex Multi-Stacked Basin, by Emilson F. Soares, Paulus H. Van Der Ven, José Eduardo F. Pinheiro, Ivanise Wolff, and Jorge J. P. de Figueiredo; #90082 (2008)

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The Foz Do Amazonas Basin — From Updated Geological Evolution of a Complex Multi-Stacked Basin

Emilson F. Soares, Paulus H. Van Der Ven, José Eduardo F. Pinheiro, Ivanise Wolff, and Jorge J. P. de Figueiredo
E&P-EXP - Exploration, PETROBRAS, Rio de Janeiro, Brazil

The Foz do Amazonas basin (FAB), in northernmost Brazil is usually perceived as being solely related to the Amazon River. However, after two decades of very low activity, renewed interest in the exploration of this region has shown this basin as having a multi-faceted and complex history.

The onset of the FAB is represented by the Cassiporé Rift, a half-graben Barremian-Albian rift related to the opening of the Central Atlantic.

From late Albian to early Paleocene a transgressive open marine drift sequence progrades eastwards over the underlying rift. A carbonate platform dominates the north of the basin whereas the southeastern area this same carbonate system is periodically intersected by the influx of terrigenous clastics. Worthy of note is the fact that during this period allochtonous sediment provenance is clearly dominated by sources placed in the Paleozoic Parnaíba basin and the Brazilian Shield located to the south, most probably carried into the basin by the Tocantins River drainage system. The Amazon was a relatively short river limited to the Purus Arch.

The onset of the Andean Uplift from late Miocene to the Pliocene had a major impact in the basin. The western Amazonia drainage system was ponded by the newly born Andes Mountains and inverted eastwards, creating what is now known as the mighty Amazonas river. As much as 9,000 meters of sediments originated from the Andes and the northern Brazilian shield were deposited into the FAB in 10.7 million years.

Provenance, biostratigraphic and geochronological studies demonstrate therefore that the Foz do Amazonas basin is a complex multi-stacked basin; each one with its own Petroleum System.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery