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

水是加州最关键、最不可预测的资源。作为一个以农业为主的经济体，加州的社会经济成功和可持续发展与水资源供应密切相关。作为美国最大的州经济，加州的健康对美国的健康至关重要。为了了解现代和未来的水资源可用性，科学家们通过研究过去来预测未来——这是一个被称为古气候学的研究领域。像莫哈韦沙漠这样的干旱环境对水的可用性特别敏感。因此，干旱环境是研究过去水循环变化的绝佳场所。该项目将以银湖（CA）为重点，结合地质、水文和建模方法，研究地球历史上最具地质和气候动态的时期之一——从末次冰期（距今约24000年）到全新世早期（距今8000年）——水可用性变化的幅度、幅度和频率。最重要的是，我们的新颖和跨学科的方法将使我们能够量化过去的水可用性变化，并评估导致这些变化的气候驱动因素。加州州立大学富勒顿分校和圣地亚哥峡谷学院（都是西班牙裔服务机构）将与布朗大学（一所主要的研究型大学）合作，为总共15名受资助的学生和1名博士后创造多样化的教育和研究体验。这种多机构合作为两年制大学生转入四年制大学提供了一条清晰的途径，并在代表性不足的群体中建立了积极的科学身份和归属感。本研究将结合盆地分析（即岩心到湖岸）、同位素和建模方法，重建冰期晚期至全新世早期填充莫哈韦冰川湖末端盆地银湖盆地所需的最小湖深、最小湖容和必要的水文气候条件的定量记录。现有的和新的海滩或近岸地貌站点将使用基于无人机的动态结构摄影测量来识别和表征。这些海岸数据及其各自的年龄将与确定日期和分析的沉积物岩心相结合，以量化24-8 ka期间最小湖泊深度的变化，从而量化湖泊体积。结合这些地质数据，项目团队将应用氧同位素约束的湖泊系统非稳态水文模型，量化在冰期晚期到全新世早期填充和维持银湖所需的必要条件。最后，将本研究的结果与各种气候强迫进行比较，以评估大盆地南部水文气候变化的主要驱动因素。该奖项由地球科学部和大气与地球空间科学部通过“当前和预测气候的古视角”项目共同资助，并增加了各种机构类型的研究能力、能力和基础设施，如GEO EMBRACE DCL所述。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.