Geochemical differences between the Cadomian granites of Mancellia and the St. Malo migmatites, Armorican Massif, France

Data sets used to suggest geochemical similarity between the St Malo migmatites and Mancellian granites are reinterpreted. The samples have complex distributions with outliers. Three non-parametric tests show significant statistical differences between the samples in Al (sub 2) O (sub 3) , CaO, K (sub 2) O, Cr, Ni, Sr, Y and Zr. If outliers are culled from the samples the differences become more extreme; the differences are also apparent on both principal component and multidimensional scaling plots. Geotectonic models based on a similar petrogenesis for the two rock units must be able to account for these differences.