HEMISPHERIC-SCALE CALIBRATION OF THE OXYGEN STABLE ISOTOPE COMPOSITION OF SMALL LAND SNAILS FROM NORTH AMERICA

The oxygen stable isotope composition (δ¹⁸O) of land snail shells is increasingly used to infer paleoclimatic conditions in the continental realm. However, the application of this proxy remains challenging because at least four environmental variables, including rainwater δ¹⁸O, relative humidity, water vapor δ¹⁸O and temperature, control shell δ¹⁸O values simultaneously, often difficult to discriminate. Furthermore, most published studies have taken place at the very local scale and have generally focused on a limited number of species. This study includes a broader (hemispheric) spatial scale approach. Hundreds of living specimens of the dominant species in both present and Quaternary sites of small land snail taxa were selected from Florida to Alaska. The measured shell δ¹⁸O values were compared to relevant climatic parameters and explored with a published snail flux balance-mixing model. Preliminary results support that small land snails from North America appear to primarily track the signature of the precipitation, and therefore, fossil snails should be potentially useful to mainly infer paleoprecipitation patterns across mid-latitudes of the northern Hemisphere.