Uso da sísmica de reflexão de alta resolução e da sonografia na exploração mineral submarina

Neto, Arthur Ayres

doi:10.1590/s0102-261x2000000300004

Cited by 23 publications

References 3 publications

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Transfer of industrial contaminants from the inner to the outer region of Sepetiba Bay (SE Brazil) by dredge spoil dumping activities: a temporal record

Saibro,

Martins,

Guerra

et al. 2023

Environ Earth Sci

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A multiproxy approach involving grain size, geophysical (resistivity, magnetic susceptibility, and P-wave velocity), mineralogical (XRD), and geochemical (elemental, stable isotopes) data has been applied to core SP9 (128 cm long) to reconstruct natural and anthropogenic changes since ≈1850 AD (anno domine) (dating by 210Pb and 127Cs methods) in a distal region of Sepetiba Bay (SB), Rio de Janeiro State (SE Brazil). The analyzed core is a fine-grained sedimentary sequence (except its upper 20 cm). It comprises detrital particles derived from felsic and intermediate source rocks, as suggested by the fields defined by the biplot Zr vs TiO2 and the Al2O3/TiO2 ratios. Despite the increase in particle size at the top of the core, there was a progressive increase in the organic matter and potentially toxic elements (PTEs) contents and nutrients such as N and P. The geophysical data allowed us to identify the presence of subsurface (biogenic) gas, which suggests the occurrence of eutrophication processes in the study area despite its location in the outer region of the bay. Core SP9 records cyclical changes over the last ≈170 years in the mineralogical and elemental composition of the sediments and type of organic matter supplied to the bottom. These changes are associated with phases of more significant oceanic influence, salinity variations in the study area, and greater or lesser oxygen depletion in the sediment. These changes may have resulted from climatic oscillations or variations in the configuration and extension of the Ponta da Pombeba spit. The extent of this structure and the anthropic activities have contributed to the contamination of this area since 1975 AD. However, statistical analyses (Pearson correlations and principal components analysis) suggest that the transport and accumulation of PTEs (mainly Cd and Zn) did not strictly follow the general pattern of sedimentary dynamics prevailing in the studied area. Results indicate that this area became strongly polluted by Cd and Zn and with high ecological risk due to dredging and spoil disposal activities at sites close to the study area. It is noted that the environmental degradation reached higher levels here than in areas close to the primary source of the metals, the disabled Ingá Mercantil Company, in Madeira Island. This work demonstrates the temporal effect of dredge disposal activities in a distal region of Sepetiba Bay for the first time. It is a strong indicator that dredged spoil areas must be selected carefully, since healthy areas can become degraded due to the dumping of polluted waste.

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Transfer of industrial contaminants from the inner to the outer region of Sepetiba Bay (SE Brazil) by dredge spoil dumping activities: a temporal record

Saibro,

Martins,

Guerra

et al. 2023

Environ Earth Sci

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Seismic echo-characters and sedimentary distribution on the South Shetland Islands continental margin, Antarctica

Magrani

Neto

2013

2013 IEEE/OES Acoustics in Underwater Geosciences Symposium

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Using side scan sonar in the characterization of the continental shelf: Touros area

Moreira

Vital

Lira

2013

2013 IEEE/OES Acoustics in Underwater Geosciences Symposium

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This paper presents a sonographic mapping of an area of the Brazilian continental shelf adjacent to Touros city-RN, NE Brazil. Data were acquired in lines parallel to the coast line, with a total area of 58 km². The equipment used was Side Scan Sonar 272 -TD, operated both with frequency of 100 kHz. As a result was possible to correlate clearly the sonar data with the satellite image and identify different reflection patterns.

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Uso da sísmica de reflexão de alta resolução e da sonografia na exploração mineral submarina

Cited by 23 publications

References 3 publications

Transfer of industrial contaminants from the inner to the outer region of Sepetiba Bay (SE Brazil) by dredge spoil dumping activities: a temporal record

Transfer of industrial contaminants from the inner to the outer region of Sepetiba Bay (SE Brazil) by dredge spoil dumping activities: a temporal record

Seismic echo-characters and sedimentary distribution on the South Shetland Islands continental margin, Antarctica

Using side scan sonar in the characterization of the continental shelf: Touros area

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