Abstract:

      Based on the analysis of the concepts of baseline and background value, the depositional environments are determined as the basic units to solve the soil geochemical baseline and the regional soil geochemical baseline are solved by means of areaweighed methodBy using the data obtained from the multipurpose regional geochemical survey in the Yangtze River Delta, the regional soil geochemical baselines of the region are gained, and their characteristics and applications are discussed.The conclusions are as follows:Various depositional environment is of its particular indicator element association.F、Cl、Br、I、Ca、Mg association reflects the relative age and proportion of marine sediments,N、S、OrgC,I、Hg and Y、Ce、La association indicates respectively the lake facies,lagoonal facies and terrestrial facies depositional environment.Hg and Cd as the pollution elements enriched in soils of the whole area;lithophile elements,rare elements and REE behaved steady;I and CaO lost easily.X₀+2S₀ adopted as the boundary values of soil pollution division of a part of elements can reflect the distribution of soil pollution.There were the fitting content nutrient elements Co and Na₂O,abundant K,N,Fe,B,Cu,Cl,Mg and S, relatively poor Zn,Mn,P,Mo and Si in soils of the area.

Key words: soil geochemical baseline, soil environmental background value, multipurpose regional geochemical survey, Yangtze River Delta