Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest
Recent studies have shown the oxygen isotopic composition (δ18O) of modern terrestrial gastropod shells is determined largely by the δ18O of precipitation. This implies that fossil shells could be used to reconstruct the δ18O of paleo-precipitation as long as the isotopic system, including the hydrologic pathways of the local watershed and the gastropod systematics, is well understood. In this study, we measured the δ18O values of 456 individual gastropod shells collected from paleowetland deposits in the San Pedro Valley, Arizona that range in age from ca. 29.1 to 9.8 ka. Isotopic differences of up to 2‰ were identified among the four taxa analyzed (Succineidae, Pupilla hebes, Gastrocopta tappaniana, and Vallonia gracilicosta), with Succineidae shells yielding the highest values and V. gracilicosta shells exhibiting the lowest values. We used these data to construct a composite isotopic record that incorporates these taxonomic offsets, and found shell δ18O values increased by ~4‰ between the last glacial maximum and early Holocene, which is similar to the magnitude, direction, and rate of isotopic change recorded by speleothems in the region. These results suggest the terrestrial gastropods analyzed here may be used as a proxy for past climate in a manner that is complementary to speleothems, but potentially with much greater spatial coverage.
Citation Information
| Publication Year | 2021 |
|---|---|
| Title | Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest |
| DOI | 10.1017/qua.2021.18 |
| Authors | Jason A. Rech, Jeffrey S. Pigati, Kathleen B. Springer, Stephanie Bosch, Jeffrey C. Nekola, Yurena Yanes |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Quaternary Research |
| Index ID | 70220612 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Geosciences and Environmental Change Science Center |
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Data release for Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest
Recent studies have shown the oxygen isotopic composition (delta18O) of modern terrestrial gastropod shells is determined largely by the delta18O of precipitation. This implies that fossil shells could be used to reconstruct the delta18O of paleo-precipitation as long as the hydrologic pathways of the local watershed and the shell isotope systematics are well understood. In this study, we measured - Connect