ARC Works in Progress Talk, Prof. Tamara Carley

Please join us for an ARC Works in Progress Talk by Professor Tamara Carley, Department of Geology and Environmental Geosciences:

Geologic Sleuthing: Tracing Alaskan ash beds of unknown origin back to their source volcano(es)

Understanding the history of explosive volcanoes is crucial for predicting future eruptions and mitigating their hazards. Tephra, a volcanic product composed of ash, pumice, crystals, and lithics, is a powerful tool for studying past eruptive behavior. Tephra studies can uncover the magnitude and intensity of an eruption; the timing and frequency of eruptive events; illuminate preeruptive magmatic conditions; hint at eruption triggers; and reveal magmatic source material and magma generating processes. However, tephra studies are only effective for reconstructing volcanic histories and predicting future behaviors if an eruptive source can be constrained. In places of high volcanic density (e.g., Alaska, the Andes, Japan), it can be difficult to determine at which of several regional volcanoes an ancient tephra deposit originated. The goal of this study is to develop an effective method for tracing tephras of unknown origin back to their source volcano, using Hf isotopes in zircon as a provenance tool and Alaskan volcanoes and tephras as a case study. This “Works in Progress” presentation will provide an overview of exploratory fieldwork and sample collection in Central Alaska, describe the process of preparing and analyzing volcanic samples, present preliminary findings, define a plan for future work, and describe Lafayette student involvement in all stages of this exciting investigation.