--> Abstract: Incised Valley System: Insights from High-Resolution Seismic Stratigraphy and Geomorphologic Modeling from the AÇU River Mouth and Shelf, Potiguar Basin, NE Brazil, by Moab P. Gomes, Helenice Vital, José W. Macedo, and Eugênio P. Frazão; #90078 (2008)

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Incised Valley System: Insights from High-Resolution Seismic Stratigraphy and Geomorphologic Modeling from the AÇU River Mouth and Shelf, Potiguar Basin, NE Brazil

Moab P. Gomes, Helenice Vital, José W. Macedo, and Eugênio P. Frazão
Programa de Pós-Graduação em Geodinâmica e Geofísica, Universidade Federal do Rio Grande do Norte, Natal, Brazil

The Potiguar Basin, located in Rio Grande do Norte State, is one of the most important petroleum provinces in Northeast Brazil. Despite the hydrocarbon production, little information is available in the literature regarding Neogene’s systems of this basin. Neogene sedimentary rock sequences of the Potiguar Basin offshore portion are composed of three lithostratigraphic units, which build up the upper part of a large regressive cycle. The Açu river paleo-valley marks the now submerged continuation of the most important river of this area (Açu River) during the last glacial sea-level lowstand. This study integrated different data sets: high-resolution seismic (chirp), gravity, bathymetric and remote sensing (LandSat7 ETM+) to mapping this morphologically-defined structure. The generated images were fused and draped over Digital elevation models to create three-dimensional (3D) perspective views that are used to analyze the 3D geometry geological features. The results show that this structure can be correlated with the former river valley, now drowned, which is filled with Pleistocene and Holocene deposits. Therefore, the entire channel structure from the mouth of the Açu River to the shelf edge can be regarded as an incised valley, cut into the shelf deposits during sea level lowstands. A continuous strong reflector, identified in all seismic profiles, represents the sea level lowstand surface. The combination of different tools allows mapping the continuity of Açu valley on the adjacent modern continental shelf in better details and develops a more comprehensive understanding of this common reservoir analog system.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas