Shelf morphology as an indicator of sedimentary regimes: A synthesis from a mixed siliciclastic–carbonate shelf on the eastern Brazilian margin

Abstract

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Seabed Morphology and Sedimentary Regimes defining Fishing Grounds along the Eastern Brazilian Shelf

“…Along the outer shelf and parts of the mid shelf, the sedimentary regime is predominantly carbonate, with development of bioclastic gravels and rhodolith beds. It is noteworthy that the carbonate sedimentation develops over an accommodation area characterized by low sediment input and relict morphological features, such as unfilled paleochannels, formed during the last lowstand [10]. Thus, carbonate sedimentation is defined by biologically-controlled precipitation (e.g., crustose coralline algae-rhodoliths), but also by bioclastic particles transport and deposition.…”

“…The shelf width varies from 50 to 200 km. Its widest part is known as the Abrolhos Shelf or the Abrolhos Bank [8][9][10]. To the south of the Abrolhos Bank, the shelf width averages 50 km and the shelf break occurs at 60 to 80 m water depth.…”

“…The Doce river is the main sediment source to the shelf, with an average load of 133 × 10 6 t during the rainy season (November to April) [11]. Shelf morphology varies significantly with four distinct regions: Abrolhos shelf, Doce river shelf, Paleovalley shelf, and the wide-southern inner shelf [10]. Here, we focus on contrasting the Doce river shelf with the Paleovalley shelf (Figures 1 and 2).…”

“…Sounding sheets represent data collected by single beam echosounders from the 60's to the 80's. Positioning accuracy may vary due to changes in coordinate acquisition systems and methodologies (for more details see [10]). Original datum in the sounding sheets was Corrego Alegre that was transformed and corrected to WGS84, following the available digital data.…”

Quantitative seismic geomorphology of a submarine channel system in SE Brazil (Espírito Santo Basin): Scale comparison with other submarine channel systems

“…1a). The width of the ESB's continental shelf increases from 50-60 km in the south to 240 km on the Abrolhos Bank in the north (Bastos et al, 2015). The modern shelf break varies in depth from 40 to 80 m (Knoppers et al, 1999;Bastos et al, 2015).…”