Sediment discrimination diagrams

Discrimination diagrams have also been applied to the environment of deposition of sedimentary rocks. Potter et al. (1965) showed that a discriminant function based upon the trace elements B and V could be used to distinguish between freshwater and marine argillaceous sediments. More recently tectonic discrimination diagrams have also been extended to sedimentary rocks. Bhatia (1983) and Roser and Korsch (1988) have produced discriminant function diagrams which allow the identification of the provenance of sandstones according to their plate tectonic setting. 

Discrimination diagrams for clastic sediments using major elements... 

In order to determine the source composition of sediments using trace elements, it is necessary to ascertain that the element is immobile under conditions of diagenesis and weathering (Spalletti 2008). Several ratios and plots may be used to define the source rocks. The felsic source rock compositions are found in the Co/Th vs. La/Sc diagram (Fig. 3 Table 1). Other trace element characteristics of sedimentary rocks also place some constrains on the nature of the source rock. Floyd Leveridge (1987) used a La/Sc vs. Hf plot to discriminate between different source compositions. In this plot, most data fall in the felsic source to mixed felsic/basic source field (Fig. 4 Table 1). 

Characterization of the sediment composition is hindered by dilution effects. PCA biplots or simple triangular diagrams avoid this. In Figure 11, a PCA biplot clearly discriminates between different lake sediments from the Jianghan Plain (Boyle et al., 1999). 

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