Internships

Samuel Bartusek ’19

This summer, I worked to perform high-precision U-Pb (uranium-lead) dating on samples from the Columbia River Basalt Province in Oregon, Washington, and Idaho. The general timing of the eruptions that produced these basalts, estimated at 17-14 Ma, corresponds with the Mid-Miocene Climate Optimum, a period of elevated global temperatures and atmospheric carbon dioxide. However, past dating performed with different methods (K-Ar, Ar-Ar) has yielded ages too imprecise to properly correlate with this climatic event. Determining precise dates and rates for these eruptions is essential to understanding their role in Miocene climate. I spent the first half of the internship in the lab at Princeton, processing samples to extract the zircon crystals used for U-Pb dating. During the second half of the internship, we traveled to the Pacific Northwest to collect samples of volcanic ash and sediment between layers of basalt, since zircons do not crystallize in the basalt itself.