Data release for Late glacial-Younger Dryas climate in interior Alaska as inferred from the isotope values of land snail shells

The isotopic values of fossil snail shells can be important archives of past climate. Here we present the first carbon (δ13C) and oxygen (δ18O) isotope values of radiocarbon-dated and live-collected snails in interior Alaska to explore changes in vegetation and humidity through the late glacial period (14-11.7 ka). Snail shell δ13C values were relatively consistent through the late glacial. However, late glacial shell δ13C values are 2.8‰ higher than modern shells. This offset is best explained by changes in the δ13C values of plants consumed by snails. Snail shell δ18O values varied through the late glacial, which can be partially explained by changes in relative humidity (RH). RH during the snail growing period was modeled based on a published flux balance model. Results suggest a dry period in the Bølling–Allerød (~14 ka) followed by two distinct stages of the Younger Dryas, a wetter stage in the early Younger Drays from 12.9-12.3 ka, and subsequent drier stage in late Younger Dryas between 12.3 and 11.7 ka. The results show that land snail isotopes in high-latitude regions may be used as a supplementary paleoclimate proxy to help clarify complex climate histories, such as those of interior Alaska during the Younger Dryas.