Modern sedimentary processes along the Doce river adjacent continental shelf

Brazilian Journal of Geology. 45(4):635-644 DOI 10.1590/2317-488920150030274

 

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Journal Title: Brazilian Journal of Geology

ISSN: 2317-4889 (Print); 2317-4692 (Online)

Publisher: Sociedade Brasileira de Geologia

Society/Institution: Sociedade Brasileira de Geologia (SBG)

LCC Subject Category: Science: Geology

Country of publisher: Brazil

Language of fulltext: Spanish; Castilian, Portuguese, French, English

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AUTHORS

Valéria da Silva Quaresma
Geórgia Catabriga
Silvia Nossa Bourguignon
Estefânia Godinho
Alex Cardoso Bastos

EDITORIAL INFORMATION

Peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 11 weeks

 

Abstract | Full Text

In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.