Geomorphology and Spatial Patterns of Sedimentation on a Modern Mix Depositional System, NE Brazil

The Brazilian continental shelf from Rio Grande do Norte State, located in the northeast of Brazil represents a modern, shallow-water mixed carbonate-siliciclastic system. This shelf is subject to the full strength of the westerly Equatorial current combined with high winds and moderate to high tides and waves. It bears important mineral resources, especially hydrocarbons and bioclastic aggregates (mainly calcareous algae). New hydroacustical data (including side scan sonar, multbeam bathymetry, sub-bottom profile), supported by diving and video transects provide unparalleled perspective on spatial distribution of environments on this area. Combined, these different sets of data allow effectively a description of the spatial variations of physical seafloor properties. The aim of this paper is to present an overview of geomorphic and sedimentologic patterns present in this modern coastal and shallow marine mix system adjacent to Potiguar Basin, which might be developed for environmental purpose and can provide examples of types of heterogeneity that might be present in ancient geologic analogs and the scales at which they occur. Different environments were observed, from beachrocks to sand dunes fields to reefs. Although the general distribution of this system have been described before this study allow a better delimitation of facies, and new founds as well, such as the coral reef presence in a wide area along the outer shelf, in water deeper than 25 m and constitute grouping of knolls, patch and bank reefs. These results are in a resolution incomparable to the existent data for this area and are very important to the increasing economic pressure on the marine environment. Moreover, a better understanding on lateral facies distribution in such modern carbonate environment can be used as analogs for reservoir description, characterization, and modeling.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California