Collaborative Research: Using a Combined Basin Analysis, Isotopic, and Modeling Approach to Reconstruct the LGM through Early Holocene Hydroclimate for Glacial Lake Mojave.

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Water is California’s (CA) most critical and unpredictable resource. As a predominantly agricultural economy, CA’s socioeconomic success and sustainability are closely tied to water availability. And as the United States' largest state economy, the health of CA is important to the health of the United States. To understand modern and future water availability, scientists look to the past to inform the future – a field of study called paleoclimatology. Arid environments like the Mojave Desert are especially sensitive to water availability. As a result, arid environments are excellent sites for studying past changes in the water cycle. This project will focus on Silver Lake (CA) and combine geological, hydrological, and modeling methods to examine the amplitude, magnitude, and frequency of changes in water availability across one of the most geologically recent and climatically dynamic periods in Earth’s history – the period from the Last Glacial Maximum (ca. 24,000 years before present) to the early Holocene (8,000 years before present). Most importantly, our novel and transdisciplinary methods will allow us to quantify past changes in water availability and assess the climatic drivers that cause these changes. Cal-State Fullerton and Santiago Canyon College (both Hispanic Serving Institutions) will partner with Brown University (a major research-active university) to create a diverse educational and research experience for a total of 15 funded students and 1 post-doc. This multi-institutional collaboration provides a clear pathway for 2-year college students to transfer into 4-year universities and establishes a positive science identity and a sense of belonging in underrepresented groups. This research will use a combined basin analysis (i.e.,core-to-shore), isotopic, and modeling approach to reconstruct a quantitative record of minimum lake depth, minimum lake volume, and the requisite hydroclimatic conditions during the Late Glacial to Early Holocene necessary to fill the Silver Lake Basin, the ostensible terminal basin of Glacial Lake Mojave. Existing and new beach or near-shore geomorphic sites will be identified and characterized using UAV-based, Structure-from-Motion photogrammetry. These shore data, and their respective ages, will be coupled with dated and analyzed sediment cores to quantify changes in minimum lake depth, and thus lake volume, from 24-8 ka. Coupled with these geological data, the project team will apply oxygen isotopic constrained, non-steady state hydrologic models of the lake system to quantify the requisite conditions necessary to fill and sustain Silver Lake during the Late Glacial to Early Holocene. Finally, the results from this work will be compared to a variety of climatic forcings to evaluate the primary drivers of hydroclimatic change in the southern Great Basin. This award is co-funded by the Division of Earth Sciences and Division of Atmospheric and Geospace Sciences by way of the Paleo Perspectives on Present and Projected Climate program, and increases research capabilities, capacity and infrastructure at a wide variety of institution types, as outlined in the GEO EMBRACE DCL.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.