Comprehensive Survey of Multi-Elements in Coastal Sea and Stream Sediments in the Island Arc Region of Japan: Mass Transfer from Terrestrial to Marine Environments

Abstract

The dispersion of sediments across terrestrial areas, estuaries, shelves, slopes, and basins in island arc regions is extremely active. Because Japan is surrounded by vast oceans, it is fundamentally important to know sediment characteristics and dispersal systems upon the shelf and slope in terms of the erosion, transport, and deposition of sediments. Coastal seas, especially inner bays, often sustain severe damage from anthropogenic activities. Geochemical characteristics of marine sediments provide valuable clues regarding the dispersion of sediments. So far, the diffusion and fixation process of elements in the vertical direction and the past sedimentary environment found in core samples have attracted considerable scientific interest. However, regional spatial distributions of the chemical compositions of sediments in land, estuaries, and coastal areas are less understood (e.g., Balls et al., 1997; Degens et al., 1991; Ibbeken & Schleyer, 1991; Irion et al., 1995; Karageorgis et al., 2005; Voutsinou-Taliadouri & Varnavas, 1995; Wang et al., 2008). To better understand the spatial distribution of the elements in the earth’s surface, a geochemical map is used. The purpose of the map is to obtain natural geochemical baselines on the earth’s surface because the geochemical history of the earth’s surface is a fundamental part of geo-information. Many countries have produced national geochemical atlases to explore mineral recourses and address growing concerns about environmental problems (Fauth et al., 1985; Gustavsson et al., 2001; Lis & Pasieczna, 1995; Shacklette & Boerngen, 1984; Thalmann et al., 1988; Weaver et al., 1983; Webb et al., 1978; Xie et al., 1997; Zheng, 1994). Simultaneously, cross-boundary and sub-continental geochemical mapping projects have actively been carried out (e.g., Bolviken et al., 1986; Reimann et al., 1998; Salminen et al., 2005). Furthermore, the International Geochemical Mapping Project (IGCP 259) was initiated in 1988 under the auspices of the UNESCO to compile data on the global geochemical composition of the earth’s surface (Darnley et al., 1995). Thus, geochemical mapping has been undertaken globally, but it is restricted to terrestrial areas because surveys of soils, stream sediments, and river water samples are easy. However, 70% of the earth’s surface is covered by water. Surveying marine sediments is important to elucidate the mass transfer from land to sea. The Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, has conducted research on the fundamental