Gunter ’11 Research Combines Interests in Archaelogy and Geosciences

Maddy Gunter '11
Maddy Gunter '11
Madeleine Gunter ’11 has had a busy and unconventional summer. An archaeology and geosciences double major, Gunter returned from several weeks on an archaeological field project off Ireland’s western coast, only to begin a micropaleontology project that will become her thesis for geosciences. Gunter is working through the data she collected on the composition of Early Medieval Christian tombstones, and using diatoms to predict Antarctic paleoenvironments.

Gunter spent the first half of her summer on the islands of Inishark and Inishboffin with Assistant Professor of Archaeology Nathan Goodale and his team. They were analyzing the composition of the headstones from several Early Medieval sites to learn more about the monastic culture that once flourished along the Irish coast.

The team wanted to understand how raw materials were used in gravestone production and whether gravestones were made from source rock close to each site or were produced in one area and transported to different sites. They also wondered whether social stratification played a role in raw material use: were higher-ranked members of the Christian community given a different type of headstone than the average monk? The process of answering these questions is complicated by the high rate at which many people reused materials since 800 AD.

But Gunter and Goodale have the tools to help solve the mysteries; they used an instrument called a portable XRF (X-Ray Fluorescence) gun, which shoots an x-ray beam at the stone. The beam excites the electrons and causes the different chemical elements of the stone to emit a signature that the machine measures. “Each rock source has a different signature, so if we can use the XRF to compare the composition of the source rock to that of the gravestone, we can theoretically tell where each gravestone was made,” Gunter explained. “Most archaeologists don’t have portable XRFs, so they can’t take readings in the field the way we can,” Gunter added. Having these tools and unique methods at their disposal allowed the team to gather a lot of reliable data and samples, which Gunter will process and analyze throughout the year as part of her senior thesis in archaeology.

Gunter is shifting her focus from Ireland to Antarctica for her geosciences project. On his trip to Antarctica this past winter, Joel W. Johnson Family Professor of Geosciences Eugene Domack collected several deep-sea sediment cores from the Hugo Island Trough, located off the Antarctic Peninsula. Gunter will determine the past environmental conditions of the Hugo Island Trough by analyzing the assemblage of fossilized diatoms, microscopic marine protists composed of silica, preserved within the core. “When looking at a core you can use different proxies to determine what the paleoenvironment was like,” Gunter explained. “There are many different proxies, which allow you to look at core in a different way. I am examining the diatom assemblage at different depths throughout the core to see if there are concentrations of specific species or warm/coldwater forms.”

There are hundreds of diatom species with different shapes and forms, but different diatoms prefer different environments and conditions. “If there is a concentration of warm-water diatom species in a section of the core, we can assume that that section represents a period of climactic warming,” Gunter said. Gunter’s analysis is complicated by the high volume and diversity of her diatom assemblage; she will need to analyze over 400 samples to fully understand the climactically-driven fluctuations in her assemblage.

Gunter is working on this project with Amy Leventer, an associate professor of geology at Colgate University and an Antarctic diatom expert. She began working on this project over the summer, and it will become her senior thesis for geosciences once the school year begins.

Gunter is a graduate of Langley High School in McLean, Va.
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