Sedimentary environment in marine sediments from two coastal areas in the Kyushu district

The coastal marine sediments should reflect various materials e.g. inflows from river, ejecta from volcano activity, aeolian dust from the continent, therefore, which are extremely important when we will examine the global environment in detail. In the previous paper, the authors have discussed on the distribution and behavior of major and trace elements in the Tokyo Bay, Mutsu Bay and Funka Bay marine sediments where locates in the east and north of Japan. In this study, major and trace elements such as manganese, iron, scandium, antimony, lanthanoids, thorium and uranium are determined by instrumental neutron activation analysis (INAA) in marine sediment core samples collected from Kagoshima Bay and Shimabara Bay in the Kyushu district of Japan. Furthermore, the sedimentary environment and the origin of the sediments in both cores are discussed using the vertical profiles of some elements (i.e. manganese, iron, cerium, thorium and uranium), the lanthanoid abundance pattern (i.e. Ce*/La* and La*/Lu* ratios), the Th/Sc ratio, the Th/U-Ce/U plot and so on obtained by INAA. Especially, it has been limited so far that the works using trace elements such as lanthanoids, thorium and uranium in marine sediments because of the difficulty of analyses for those elements. (author)