Characterization of alkaline earth elements in the Seto Inland Sea sediments

Characteristic distributions of alkaline earth elements in sediments collected from the Seto Inland Sea was described. Some alkaline earth elements, such as magnesium, calcium, strontium and barium, in the sediments were determined by a X-ray fluorometry. The vertical distributions of these elements appeared not to be affected by post-depositional diagenesis. The weakly negative correlations were found between magnesium and calcium and strontium. Although the anomalous concentrations of calcium and strontium weir observed in Hibiki-nada, relatively high correlation between the elements was obtained in the Seto Inland Sea sediments. The correlation coefficient between calcium and strontium was 0.97. Chemical species of alkaline earth elements in the sediments were estimated by a chemical leaching technique. A large portion of calcium and strontium weir deposited as carbonate. The variation of a Sr/Ca ratio in the sediments obeyed Freundlich's isotherm equation over the entire samples. The generic correlations between the elements could be interpreted in a term of coprecipitation phenomenon of strontium by calcium carbonate from the water column. (author)