OXYGEN ISOTOPE VALUES OF MODERN AND FOSSIL LAND SNAILS FROM FAIRBANKS, ALASKA

Polar regions are critically impacted by accelerated climate warming. Snails and other Arctic species are well adapted to cold environments and are likely to struggle in future warmer scenarios. Additionally, sub-fossil and fossil records in permafrost deposits are facing disturbance and destruction due to fast-rising temperatures and accelerated melting. Therefore, there is an urgent need to study these records and generate proxy data useful to investigate paleoclimate cycles for predicting the trajectory of current and future climate scenarios. Terrestrial gastropods, or land snails, are abundantly preserved in Quaternary permafrost and loess deposits in Alaska, but they remain poorly studied. Here, we analyze the oxygen isotope values of modern (live collected) and fossil land snail shells preserved in the Fox permafrost tunnel near Fairbanks, Alaska, to evaluate differences in precipitation δ¹⁸O between the modern and the recent past. We isotopically analyzed the three most abundant genera of land snails (Succinea, Euconulus, and Vertigo). Preliminary radiocarbon dates (n = 3) indicate that fossil snails are from ~14 cal kya. The three snail species exhibited significantly different oxygen isotope values, suggesting that sympatric snail taxa should be considered separately in local or regional paleoclimate studies. In sharp contrast to ice-core records, the preliminary oxygen isotope results of snails from the end of the Pleistocene are statistically indistinguishable from modern shells of the same species. The similarity in oxygen isotope values may be explained by the influence of ¹⁸O-enriched glacial ocean waters, and/or increased aridity during glacial intervals. Future research aims to isotopically analyze and date more snails throughout the Fox Tunnel to assess if this pattern holds true with increasing sample sizes and across time intervals.