Document Type


Date of Degree Completion

Spring 2024

Degree Name

Master of Science (MS)


Geological Sciences

Committee Chair

Dr. Hannah Shamloo

Second Committee Member

Dr. Chris Mattinson

Third Committee Member

Dr. Susan DeBari

Fourth Committee Member

Dr. Kristina Walowski


Mount Baker, ranked as a very-high threat volcano in the United States, is in a well-populated area in northern WA, putting many at risk in the event of a future eruption. Previous work on Mount Baker focused on understanding the magmatic architecture beneath the volcano and has identified multiple magmatic components that contributed to different eruptions throughout its history. The youngest lava flow in the Mount Baker Volcanic Field is the 9.8 ka Sulphur Creek lava flow. The last study conducted on this flow by Garvey (2022) determined the most recent magma mush configuration that was tapped for this eruption. This included finding four co-crystallizing mineral assemblages and their respective equilibrium liquids representing four distinct magma components stored at a variety of depths beneath Mount Baker. However, it is still unknown how long these magma components were stored in an eruptible state before the eruption and how quickly the final ascent of magma to the surface was after the eruption initiation mechanism. Using EPMA and LA-ICP-MS, chemical gradients across individual crystals were collected for thermometry and diffusion chronometry. The Mg and Sr concentration gradients across core to interior zone boundaries in plagioclase were fit by diffusion models at 750 °C and produced median residence timescales of 164 ± 772, 34 years and 656 ± 927, 396 years, respectively. The Mg gradients across interior zones to rims of plagioclase and Fe-Mg interdiffusion in clinopyroxene were analyzed using the temperatures calculated via mineral-liquid thermometers in ThermoBar (Wieser et al., 2022) to produce median eruption initiation timescales of 1.3 ± 2.4, 0.7 months and 7 ± 6, 5 years, respectively. This work provides insight into timescales associated with an active magma system in the Cascades that has no diffusion studies to date and assists in planning for hazard and risk mitigation in the case of a future eruption at Mount Baker.

Available for download on Saturday, June 14, 2025