Postdoctoral Fellowship: OPP-PRF: A Novel Method for High Resolution Chemical Imaging and Dating of Old Ice Cores using Laser Ablation Inductively Coupled Plasma Mass Spectrometry

Understanding Earth’s past climates is crucial for predicting future climate change. Ice cores, especially those from polar regions, provided remarkably detailed information about past climates, atmospheric conditions, and environmental changes spanning past 800,000 years. The recent discovery of oldest ice on Earth (over 1 million years old) from cores drilled trough Antarctica's blue ice areas (BIAs) is a significant breakthrough in contextualizing our planet's climate history using a time with elevated atmospheric carbon dioxide levels and warmer global mean temperatures. This project will develop advanced methods for analyzing and dating ice cores from BIAs. Detailed mapping of the elements within the ice layers and determining their ages will uncover the new details on Earth’s climate history preserved within these ancient pieces of ice. Currently, paleoclimate reconstructions using samples from Antarctica's BIAs face at least two major challenges: (1) the lack of multiple independent chronometers for dating stratigraphically disturbed ice greater than 1 million years old, and (2) uncertainties in the stratigraphic orientation and thickness of layering in old, folded ice. This research will address both of these through the development of a novel analytical technique using cryo-cell laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). LA-ICP-MS has emerged as a powerful method for high-resolution in situ analyses of impurities in polar ice cores. This approach will enable researchers to achieve high spatial resolution of the 2D elemental maps of impurity distribution, identify layering, and date ice cores using 87Sr/86Sr ratios of trapped sea-salts. The development of these new analytical methods will significantly enhance our ability to interpret the age and stratigraphic orientation of deformed ancient ice, thereby creating more reliable paleoclimate archives. The outcomes of this research will contribute to other ongoing initiatives to recover the oldest possible ice cores in Antarctica, extending past climate reconstructions beyond the million-year time scale. This project includes training and mentorship of undergraduate and graduate students on the use of LA-ICP-MS and facilitate knowledge exchange and outreach about climate research through a collaboration with the Princeton Student Climate Initiative. 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.