Radiometric and stimulated luminescent characterization of Amazonian sediments from the Middle Rio Negro, Western Amazon

The sediments were collected from paleodunes, river terraces, islands, and sand bars at Mariuá Archipelago, Rio Negro, Brazil. XRD analysis revealed that quartz is the predominant mineral along with a trace quantity of kaolinite. Neutron activation analysis of the sediments revealed the assembly of...

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Published in:	Radiation physics and chemistry (Oxford, England : 1993) Vol. 212; p. 111117
Main Authors:	Tatumi, Sonia H., Yee, Márcio, Soares, Emílio A.A., de Souza, Jefferson J., Grudzin, Emanuele D.O., Munita, Casimiro S., Ribeiro, Rogério B., de Farias Soares, Alvaro, Silva, Noemi Aguiar, Fernandes, Caroline P., Mathias, Matheus T., Rocca, René R., Nagabhushana, K.R., Lokesha, H.S., Rocha, Marcelo S., Lopez, Luis A.C., Venâncio, Diego W.P., Costa, Solange dos S.
Format:	Journal Article
Language:	English
Published:	Elsevier Ltd 01-11-2023
Subjects:	Amazon basin Fluvial sediment Neutron activation analysis Optically stimulated luminescence Phototransfer TL Radioactive isotopes Phototransfer TL Neutron activation analysis Optically stimulated luminescence Amazon basin Radioactive isotopes Fluvial sediment
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Summary:	The sediments were collected from paleodunes, river terraces, islands, and sand bars at Mariuá Archipelago, Rio Negro, Brazil. XRD analysis revealed that quartz is the predominant mineral along with a trace quantity of kaolinite. Neutron activation analysis of the sediments revealed the assembly of rare-earth elements, metals and semi-metals. The values of U and Th were found to be 3–5 ppm in paleodunes and 9–16 ppm in terraces, and K-40 concentration is below detectable limit. The OSL of quartz (dune) is composed of three components with decay times of 0.2, 11.0 and 350 s, respectively. This OSL emission is related to the TL peaks below 380 °C. Also, photo-transferred TL is observed in the temperature range of 190–250 °C for a blue stimulation of 500 s. TL peaks kinetic parameters were calculated and discussed. The lifetimes of TL peaks at 272 and 355 °C are approximately 4.0×104 and 1.5×109 years, respectively. Using the conventional SAR protocol, 11 samples were dated, including two old paleodunes with ages of 124.4 and 169.7 ka, increasing the age interval of the site, the other samples were younger sediments, with ages between 0.39 and 53.9 ka. •The sediments of Mariuá Archipelago, Amazon, were dated by OSL-SAR protocol.•Sediments have predominant quartz and subordinate kaolinite confirmed by XRD.•INAA shows a large assembly of rare-earth elements in the sediments.•Ages of Aeolian dunes are in the order of 102 ka and fluvial sediments have ∼10 ka.•PTTL is observed in quartz (paleodunes) for blue light stimulation time above 500 s.
ISSN:	0969-806X 1879-0895
DOI:	10.1016/j.radphyschem.2023.111117