630 ka Lava Creek Tuff Exchange with Isotopically Labeled Water: Testing the Stability of D/H Paleoenvironmental Signals

Presenter: Abigail Ross

Faculty Mentor: Angela Seligman, Ilya Bindeman

Presentation Type: Poster 35

Primary Research Area: Science

Major: Geology

Funding Source: UROP Mini-Grant Recipient, $1000; Department of Geological Sciences

Studies focused on paleoenvironments are becoming increasingly popular and relevant as we begin to understand future climatic patterns through studying those of the past. Isotopic ratios of hydrogen and oxygen of volcanic glass that has been hydrated by surrounding environmental waters have been used as paleoclimate indicators through inferring the isotopic values of past meteoric waters. By testing the exchange of hydrogen and oxygen isotopes

of hydrated volcanic glass with surrounding water, we analyze the validity of this method. This project focuses specifically on the element of age, evaluating if a significant difference in deposition time makes a difference in the isotope’s ability to re-equilibrate, as was suggested by Cassel et al. (2014).

Nolan and Bindeman (2013) placed hydrated ash from the 7.7 ka eruption of Mt. Mazama in isotopically labeled water and observed that the H2O and d18O values remained constant, but the dD values of ash increased with the surrounding water, INDICATING THAT XXX. My research expands on this work by conducting the same experiment, but with ash from the 630 ka Lava Creek Tuff eruption of Yellowstone to see if significantly older glass produces similar results. Preliminary data show that exchange of hydrogen isotopes of hydrated glass is not limited by the age of the glass, and that the use of hydrogen isotopes of secondarily hydrated glass may not be a reliable paleoclimate indicator.