Abstract
In order to characterize the geochemical behavior of elements in the biological and sea salts origin materials, the whole major elements together with the biogenic silica (Bio.SiO2), carbon dioxide (CO2), and water soluble chlorine (Cl) were analyzed for about 200 coastal marine sediments collected around the Japanese islands. The average abundance of Bio.SiO2 is the most higher in sediments from off SE Hokkaido which have been affected by the Oyashio current. The sediments from off Tokai situated in the region of the Kuroshio current are clearly depleted in Bio.SiO2. The Bio.SiO2 and Cl are generally enriched in the fine sediment fraction than the coarse one, and positively correlated with water depth of the sampling stations. The CO2is dominant in the coarse sediment distributed in relatively shallower water depth. Although most representative carbonate mineral is CaCO3,dolomite is occurred in some samples containing a large amount of CO2. It is considered that all the heavy metals containing toxic trace elements are not enriched in the sediments of Bio.SiO2, carbonate minerals and sea salts. In general, most heavy metals are contained more in fine fractions than coarse fractions of sediments, and those are sometimes enriched during the early diagenesis. The evaluation of biological and sea salts origin materials in the coastal marine sediments will be indispensable for estimation of geologic background in the catchment area.
