Abstract
In order to characterize the variation of elemental concentrations according to the grain size classification, a total of 795 river and marine sediments were analyzed for major and minor constituents. Almost all the constituents of the river sediments are enriched more in the fine fractions than in the coarse ones, but both K and Ba are often abundant in the coarse fraction of sediments. The K and Ba abundant coarse sediments are commonly derived from the felsic rocks containing a large amounts of potassium feldspar. In the case of some muddy river sediments collected in the plain areas, somehow P, Cu, Zn and C are enriched more in the coarse fraction than in the middle fraction of sediments. In this case, the coarse sediment particles consist mainly by the nodules which composed of small clastic materials, clay minerals and biogenic materials. Although most constituents of the marine sediments are also much dominant in the fine fraction than in the coarse one, Ca, Sr and As are generally enriched in the coarse grain sediments distributed in relatively shallower water depth. There is no clear increasing or decreasing tendency in the abundance of Fe, Co, Ce, U and Y according to the grain size classification. High concentrations more than five times over background abundance are found for Mn and Mo in the fine sediments collected in the deeper water depth of the Japan Sea. The significant amounts of Ca and Sr in the coarse marine sediments are derived from the calcareous materials such as shell and coral fragments and/or calcareous algae. The anomalous behavior of As, Fe, Co, Ce, U, Y, Mn or Mo concentration according to the grain size classification may be caused by the process of weathering and diagenesis in the marine environments.
