COLLABORATIVE RESEARCH: Investigating the link between modern spring activity and associated paleospring mounds in Death Valley, NP

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In the coming decades, climate change is projected to reduce water availability in dryland regions and the already water-stressed regions of the southwestern United States. In order to implement sustainable water resource policies, a thorough understanding of regional climate history is essential. The PIs will investigate previously undescribed terrestrial limestone rocks that form from spring activity (travertine) from Keane Wonder Spring (KWST), Death Valley, National Park to reconstruct the timing of past wet events. In addition to their potential as past recorders of the regions’ hydroclimate, travertine deposits serve to better understand how microbial communities that inhabit the spring water and associated sediment become part of the fossil record, thus informing the interpretation of the earliest records of life on Earth. Results from this research will help elucidate past changes in the regions’ hydroclimate and help inform our understanding of the pathways that govern microbial fossilization. This study will support three early to mid-career faculty, two graduate students and five undergraduate students at three institutions (two of which are minority-serving institutions). Training for students and class field trips will provide unique research opportunities for undergraduates including field surveys and lab processing methods. Recent work summarizing global trends in travertine deposits indicates that peaks in deposition correspond with local times of high precipitation or wet conditions. Travertine deposits are common in Death Valley, but their reliability as hydroclimate archives has not been fully vetted across multiple climate transitions and necessitates comparison with well-calibrated, proximal hydroclimate records. In addition to their paleoclimate archive potential, travertine deposits are sensitive recorders of interactions between microbial communities and their environment, making travertine a target setting to assess the morphology and function of fossilized microorganisms. The PIs will use a suite of geochemical and microbiological analyses of modern spring water and associated modern travertine growth along distinct facies types of a spring flow transect to reveal the extent to which active travertine accretion records and preserves microbiological, geochemical, and hydrologic signatures. The PIs will analyze Quaternary travertine deposits at KWST and use a suite of geochemical and geochronological analyses to establish the timing of hydroclimatic changes in the region.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.