Julian Cohen presents the results of his Masters thesis work: analysis of stable isotopes from ancient meteoric water preserved in volcanic glass shards from the approximately 7 Ma Rattlesnake Ash Tuff Flow (RST). Stable isotopes in meteoric water are known to have abundances relative to various environmental characteristics including temperature, elevation, and amount of precipitation. Understanding the stable isotope composition of ancient water is a useful proxy for ancient climate.
Julian discusses the details of his field and lab work, characteristics of the RST, depositional history, petrogenesis, and the significance of his findings. His conclusions include paleoenvironmental interpretations within the existing environmental framework previously established for the late Miocene.