Stable isotope analyses on the last 30 ka molluscan fauna from Pampa grassland, Bonaerense region, Argentina

摘要: Abstract Fossil and living shells of terrestrial freshwater molluscs collected from various sites in the Bonaerense Patagonia regions Argentina were analysed for their stable isotope content as a possible tool palaeoclimatic palaeoenvironmental reconstruction. The oxygen composition calcareous shell samples was interpreted terms change moisture condition related evaporative effect on surficial bodies water, linked to climatic shift. carbon mainly records changes biological productivity. Interpretation isotopic land snail carbonate is more complex worldwide data have been used decipher some extent record contained composition. Overall, interpretations deduced snails well nearby are quite comparable. suggest that arid conditions occurred between 35 15 ka B.P. warmer around 35–25 A shift toward new phase comparable with present meteorological situation probably began 9 it short but severe fluctuations, thus suggesting high stress characterised this period. Moreover, trend slightly suggested by data, possibly sometimes after 5 ka. differences arising geographical location duration each single series studied still hamper an extensive interpretation data.