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Colloquium: "The Relationship Between Massive Volcanism and Mass Extinctions: Insights from Mercury Anomalies and Isotopes”

Tuesday, September 4, 2018 - 4:00pm to 5:00pm
022 Deike

On Tuesday, Sept. 4th, Colloquium Speaker Alyson Thibodeau, Assistant Professor, Department of Earth Sciences, Dickinson College, presents "The Relationship Between Massive Volcanism and Mass Extinctions: Insights from Mercury Anomalies and Isotopes” at 4 p.m. in 022 Deike. A pre-talk Coffee & Cookies Speaker Reception takes place at 3:45 p.m. in the EMS Museum on the ground floor of Deike. All are welcome.

More About Dr. Alyson Thibodeau

Assistant Professor

Department of Earth Sciences

Dickinson College



Ph.D., Geochemistry, University of Arizona

M.S., Isotope Geochemistry, University of Arizona

B.A., Geology and Anthropology, Amherst College


Research Interests and Activities

Thibodeau uses geochemical and isotopic approaches to decipher both the geologic and human past. Her research primarily involves using radiogenic and non-traditional metal stable isotopes as tracers and chronometers of Earth surface processes and to address questions of provenance. 

One specific area of Thibodeau’s research is the fourth of five known extinctions--the end-Triassic period—where she has found higher than expected levels of mercury in the fossil record. She believes these findings indicate that massive volcanism played a large role in the extinction and that life did not recover until this volcanism ceased. Similar studies have used mercury to investigate the role of volcanism during other mass extinctions, but this is the first study to investigate mercury levels during the end-Triassic period. As CO2 continues to rise, it is critical to consider how the Earth responded to similar perturbations in the past. “This study is of interest to a popular audience because it investigates the biological/ecosystem response to massive environmental changes that were at least partially driven by the release of large amounts of CO2 and other volatiles to the atmosphere by massive volcanism,” says Thibodeau.  

Thibodeau also participated in a decade-long collaboration between archaeologists and isotope geochemists to understand the nature of turquoise circulation and trade across southwestern North America. In published research, she showed that isotopic signatures could distinguish among turquoise deposits across the Southwestern U.S. and identified the geologic sources of turquoise artifacts from archaeological sites in Arizona and New Mexico. Thibodeau said that the long-standing assumption that Mesoamerican civilizations imported turquoise from the Southwest had not been fully substantiated with evidence, and that the new geochemical measurements unveil a different story.

Prior to joining the Dickinson College faculty, Thibodeau was a postdoctoral Fellow at the University of Toronto’s Department of Earth Sciences.

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