The ITRAX core scanner, a useful tool to distinguish anthropic vs. climatic influences in lagoon of Aveiro (N Portugal)

• Published in: Journal of coastal research 2013-01, Vol.1 (65), p.70-70
• Main Authors: Martins, Virginia A, Dias, Joao A, Bernardes, Cristina, Rubio, Belen, Bernabeu, Ana, Rey, Daniel, Soares, Antonio M, Sobrinho, Frederico, Laut, Lazaro M, Frontalini, Fabrizio, Terroso, Denise, Miranda, Paulo, Fernandez-Fernandez, Sandra, Rodrigues, Maria Antonieta, Figueira, Rubens, Sousa, Silvia, Amaral, Paula, Mahiques, Michel, Rocha, Fernando
• Format: Article
• Language: English
• Subjects: Aluminum; Carbon; Channels; Coastal; Coasts; Environmental impact; Lagoons; Organic carbon; Sand; Sediments; Tidal currents; X-ray fluorescence
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/SI65-013

This paper aims to distinguish anthropic and climatic influences in sediments from the lagoon of Aveiro (Portugal). This study is based on a core (240-cm long) collected in Murtosa Channel. Optical and X-radiographic images and high-resolution elemental profiles were acquired with ITRAX micro-X-ray fluorescence (XRF) core scanner. Samples collected at each approximately 3 cm along the core were analysed for grain size and total organic carbon. Furthermore, the fine fraction of selected layers was subjected to geochemical analysis by ICP-MS, after total acid digestion of the sediments, and mineralogical analysis, by XRD techniques. Sediments along the core are composed by fine and medium sand, with several mud layers. The progressive increase of Si/Al, Cl/Al, Rb/Al, K/Al and Br/Al and reduced Al concentrations, from the base to the top of this core, are interpreted as being related to higher marine influence and greater differences in tidal currents with longer exposition to air of the sediments with the consequent formation of brines favouring minerals precipitation in the area (e.g. anhydrite).