Geochemical and Sr-Nd isotopic characterization of Middle Pleistocene sediments from the paleontological site of La Polledrara di Cecanibbio (Sabatini Volcanic District, central Italy)

The 87Sr/86Sr ratios of the samples (0.710182-0.710433) support the distinction of the sediments based on chemistry and mineralogy, and their Sabatinian origin. The isotopic range overlaps that in the lavas of Phases III-IV of the SVD and is slightly lower than the range in the TFVLS, likely because of advanced analcitization of the sediments. The ammonium acetate extracts from the samples show a narrow isotopic range (0.709613-0.709735), which is lower than the range of the bulk sediments but close to the isotopic composition of fossil elephant remains in the Polledrara sediments. Lastly, except for the most SiO2-rich sample exhibiting a higher value (0.512227), the 143Nd/144Nd ratios of the other samples show a narrow range (0.512147-0.512171) and cannot be distinguished from each other. The isotopic range is similar to that of the TFVLS, but higher than that of Sabatinian lavas, supporting the origin of the sediments from the former rocks.