Sr-isotope ratios of a soil profile (badlands) at Radicofani (Southern Tuscany)

The Sr/Ca ratios and Sr-isotope ratios of bulk samples and acetate extracts from a soil profile developed on Pliocene marine clays near Radicofani, in southern Tuscany, have been determined. The uniform Sr/Ca ratios of bulk soil indicate a uniform distribution of the two elements throughout the profile. In contrast, the lower Sr/Ca ratios of acetate extracts from the upper horizons of the soil suggest preferential removal of Sr relative to Ca, perhaps by the plants. These latter seem to accumulate Sr relative to Ca during their lifetime. The δ87Sr of acetate extracts suggest that bulk Sr is provided by the calcite derived from the Mesozoic-Cenozoic sedimentary formations of southern Tuscany. Another source of Sr, although subordinate, is represented by clastic albite. A grass sample growing on the soil shows Sr uptaken from both sources.