Holocene Water Balance of the Northeastern Great Basin

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This award supports the generation of stable isotope proxy records to study the Holocene hydroclimatology of the Great Salt Lake (GSL) catchment of northern Utah, southeastern Idaho, and southwestern Wyoming. Samples for this project are from cores drilled by the DOSECC continental drilling consortium and archived in the national LacCore core repository. Although study of the pre-Holocene GSL sedimentary record preserved in these cores has advanced during the last 5 years, the paleoenvironmental records preserved in the Holocene cores remain largely un-tapped. The award supports analyses of organic, mineralic, and compound-specific stable isotope ratios. Reconstructions derived from these records provides the first high-resolution (sub-centennial) records of the Holocene water cycle from this part of the western U.S. spanning the last 10,000 years. The hydroclimatological reconstructions are used to test hypothesized mechanistic relationships between local, regional, and global climatological change and periods of sustained (decadal to centennial scale) drought in this region, and to identify how global and regional climate change during the Holocene impacted the frequency and intensity of such events. In addition to providing tests of climate hypotheses, these records serve as a benchmark for future studies of Holocene environmental change in the Great Basin. The work is particularly relevant to the research area of "Holocene climatic variability, forcing mechanisms, and impacts" highlighted by the Earth Systems History program.Intellectual Merit The project generates improved understanding of natural hydroclimatological variability in the American West. The records generated complement related datasets from lakes in Nevada and California, revealing spatial and temporal changes in the water cycle. These findings benefit ongoing research on Holocene floras, faunas, and archaeology by providing important environmental context. The work provides data targets for paleoclimate modelers and informs their understanding of climate mechanisms driving water cycle change in the western U.S. It contributes pre-historical background for a proposed hydrological observatory to be located in the GSL Basin. The project also explores methodological advances in stable isotope paleoclimatology, furthering the use of proteinaceous fossils for hydroclimatological research and multi-proxy stable isotope datasets to reconstruct past environmental change.Broader ImpactsThis award supports the scientific education and training of a female Ph. D. student, advancing the participation of women in the Earth sciences. During the course of the project, the student will gain experience in scientific project planning, analytical and experimental methods development, stable and radiogenic isotope analysis, data interpretation and modeling, and presentation and publication of research results. The project presents opportunities for undergraduate research and for involvement of students from underrepresented groups recruited through active minority participation programs at Purdue. The results of the study are disseminated widely to the scientific community through publication, presentations at the annual meetings of major scientific societies, and data distribution via centralized web-accessible portals (e.g., CHRONOS). Given the great potential sensitivity of water resources in the study area to future climate change, the research is socially relevant and may be expected to impact future water policy decisions. Transfer of knowledge from this project to the broader scientific and policy communities is enhanced through the activities of the Purdue Climate Change Research Center.