EMBRACE-EAR-Seed: Refining paleotemperature interpretations: High resolution study of the seasonality of fluid inclusion development in halite crystal growth

Lake water that gets trapped in salt during its formation can be used to determine water temperatures at the time of crystal precipitation and ancient salt minerals have the potential to provide a record of past temperatures. However, it remains unclear whether these temperatures reflect either daily, seasonal, maximum, minimum, or annual temperatures. This project aims to understand what kind of temperature records are preserved in salt precipitated in saline lakes through controlled laboratory experiments and the study of modern natural samples. The trapped fluid in precipitated salt, the so called “fluid inclusions”, will be analyzed through laboratory experiments at a range of temperatures to assess how fluid inclusions register temperature during salt crystal growth. In addition to laboratory experiments, fluid inclusion samples will be analyzed from salt minerals precipitated in the Great Salt Lake. The Great Salt Lake is a shallow saline lake that represents an ideal natural system to study fluid inclusions as salt forms at a range of highly variable conditions. Improving understanding of how fluid inclusions in salt track temperature in laboratory and modern lake systems will lay the foundation for interpreting data from ancient samples to infer past environments. SUNY Broome Community College students will be participating in this research in collaboration with Binghamton University and the Utah Geological Survey. This provides community college students with hands on applied learning and research experience. Minerals like halite precipitate at or near Earth’s surface conditions, and cavities in mineral crystals trap water during their growth. These trapped water samples or “fluid inclusions” can then be used to infer the temperature during crystal growth and calculate water compositions. Although fluid inclusions have been used for many decades for paleoenvironmental interpretations, calibration and validation of fluid inclusions through experimentation and sampling in modern environments remains to be done. This EMBRACE-EAR-Seed project will generate standards of practice for fluid inclusion microthermometry interpretation and will lay the foundations for further work on high resolution paleotemperature reconstructions through geologic time. The Eocene time interval, in particular, experienced the great variability in temperatures that ranged from the warmest average temperatures of the Cenozoic at the beginning of the Eocene, to icehouse conditions by the end of the epoch. The calibration and validation of fluid inclusions from halite from this project will deliver an improved proxy to study past environments from samples preserved in ancient saline basins. Relevant, real-world undergraduate research will enhance the existing undergraduate research program within Broome Community College’s Environmental Science program (2-year Community College) and strengthen the collaboration with Binghamton University (R1 Institution). 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.