Geochemical correlation of bentonites from Nilos Island, Aegean, Greece

Major and trace chemical elements from eleven Lower Pleistocene bentonite d eposits from Eastern Milos Island, Aegean, Greece, were used for geochemica l fingerprinting of the bentonites, by means of scatter binary and ternary plots and canonical discriminant analysis. The trace elements were selected according to their immobility during bentonite formation and subsequent hy drothermal alteration. The bentonites can be separated into at least four g eographically distinct groups, each consisting of materials with similar ge ochemical affinities. The deposits of each group were derived from protolit hs erupted from different volcanic centres, suggesting the existence of at least two distinct volcanic provinces, having rhyolitic and andesitic affin ities respectively. Several deposits consist of more than one bentonite hor izon, indicating that in some volcanic centres the character of volcanism c hanged with time. Geochemical fingerprinting, supplemented with geological, mineralogical, and textural evidence, may be useful for correlation and ex ploration of bentonites, in terrains with complex geological histories.