ON THE CLASSIFICATION AND NORMALIZATION O F INCOMPATIBLE TRACE-ELEMENTS - A DISCUSSION

In two recent papers, Schiano, Dupre and their co-workers [Schiano et al., 1993 ; Dupre et al., this volume] define a new quantitative param eter allowing classifications of incompatible elements. They show that the relative standard error of each element in a data set, is directl y correlated to the bulk partition coefficient during partial melting and magmatic differentiation. This new parameter (<< Variability V >>) justifies many standard geochemical tools (such as extended rare eart h diagrams or << spidergrams >>). However, in some cases the resolutio n of this new parameter is unable to refine the method mentioned above .