『Abstract
　In all, 53 elements were analyzed in 1406 coastal sea sediment samples collected from an area off Hokkaido and the Tohoku region of Japan during a nationwide marine geochemical mapping project. The spatial distribution patterns of the elemental concentrations in coastal seas along with the existing geochemical maps in terrestrial areas were used to define natural geochemical background variation and mass transport processes. The terrestrial area is covered by mafic volcanic rocks and accretionary complexes associated with ophiolite, which has small amounts of felsic volcanic rocks and granite. The spatial distribution patterns of elements enriched in mafic lithologies such as Fe (Total Fe2O3) and Sc in marine environments are influenced by adjoining terrestrial materials. The spatial distribution patterns of Cr and Ni concentrations, which are highly abundant in ultramafic rocks on land, are used to evaluate the mass transport from land the sea and the dispersive processes caused by oceanic currents. The scale of mass transport by oceanic currents occurs up to a distance of 100-200 km from the coast along the coastal areas. The regional differences of elements rich in felsic lithologies such as K(K2O), Nb and La in marine sediments are determined mainly by the relative proportion of minerals and lithic fragments enriching felsic materials to those associated with mafic materials. The spatial distribution of elemental concentration is not always continuous between the land areas and coastal sea areas. That difference is interpreted as resulting from (1) transportation of marine sediments by oceanic currents and storm waves, (2) contribution of volcanic materials such as tephra, (3) occurrence of shell fragments and foraminifera tests and (4) distribution of relict sediments of the last glacial age and early transgression age. Contamination with Cu, Zn, Cd, As, Mo, Sn, Sb, Hg, Pb and Bi was not observed in marine environments because the study area has little anthropogenic activity. Terrestrial materials are the dominant source for these metals. The Mo, Cd, Sn, Sb, Hg, P`b and Ni are abundant in silty and clayey sediments locally because of early diagenetic processes, authigenic precipitation and organic substances associated with these elements. The spatial distribution of As concentration shows exceptions: it is concentrated in some coarse and fine sands on the shelf. The enrichment is explained by adsorption of As, sourced from a coal field, to Fe hydroxide.』

１. Introduction
2. Study area
　2.1. Coastal sea areas
　2.2. Terrestrial areas
3. Materials and methods
4. Geochemical map preparation
5. Results
　5.1. Spatial distribution patterns of elemental concentrations in coastal seas and adjoining terrestrial areas
　　5.1.1. Spatial distribution of elements in terrestrial areas
　　5.1.2. Spatial distribution of elements in marine sediments
　5.2. Variation of elemental concentrations in coastal sea sediments according to particle size
6. Discussion
　6.1. Mass transport processes: contribution of terrestrial materials and transportation of sediments by coastal currents
　6.2. Relict sediments formed during the last glacial age and the early transgression age
　6.3. Influence of volcanic activity
　6.4. Influence of anthropogenic activity, mines, early diagenetic processes and biogenic activity
　6.5. Relationships of elemental abundance in coastal sea sediments between regional distributions and particle size effects
　6.6. Major factors determining the distribution of elements in coastal seas
　6.7. Comparison of elemental abundance in coastal sea sediments and stream sediments
　　6.7.1. Controlling factors of spatial distribution of mafic components
　　6.7.2. Controlling factors of spatial distribution of felsic components
　　6.7.3. Controlling factors of As, CD, Mo, Sn, Sb, Hg, Pb and Bi
7. Summary
Acknowledgements
Appendix
References