Tibbits opens 2022 Graves Lecture Series

Tibbits’ lecture, Ray Guns and the Ancient Maya: Geoarchaeology in Belize, discussed the stone tools Maya people used to grind grain and specialized geologic measuring systems she used to trace the origins of the tools.

Tibbits described matatas (meh-tah-tays) and monos, as grinding stones used to process grain by the ancient Maya.

“A matata (is) the grinding stone and the mono is dragged across the surface to grind up food or pigments or different materials,” she said.

Matatas and monos could be made of many materials including basalt and sandstone, but Tibbits focused her research on tracing those made of granite with the hope of understanding more about Maya civilization.

“One of the things I wanted to look at was how the stone grinding tools informed us about these changes in power,” Tibbits said. “Who controls the monos and matatas, controls the household economy.”

Tibbits detailed the political and cultural structure of the Maya civilization and how archeological artifacts contribute to that understanding.

“(In the Maya civilization) we have large centers that dominate, and they fought each other all the time. They were constantly vying for who was in charge of what, and again, a lot of times we see this through elite goods, things that the elite would have had control over that were imported from elsewhere,” Tibbits said.

According to Tibbits, in that region of the Maya world there were three main sources of granite: the Cockscomb Basin, the Hummingbird Ridge, and the Mountain Pine Ridge. Tibbits’ research traced where existing monos and matatas were sourced from to try to understand how the Maya acquired their grinding tools.

To determine the source of the granite tools, Tibbits used a portable X-ray Florescent gun (pXRF), a new archeological technology.

“Within 30 seconds you can have a complete chemical output from magnesium to uranium on the periodic table,” Tibbits said.

According to Tibbits, the pXRF is nondestructive and about the size and shape of a power drill.

“You can use it on soil, rocks, ceramics, glass, obsidian, chert, anything that’s solid,” she said.

Tibbits worked to find ways to use the pXRF to identify granite samples in the field.

“With my statistical tests, if you use five randomly selected data points and average them, you can statistically create the same data point as grinding it up, powdering it, and shipping it off,” Tibbits said.

She used three elements present in the granite samples, strontium, rubidium, and vitreum, to identify their points of origin. By identifying where the granite came from and noting where it was unearthed at a dig site, Tibbits was able to trace the journeys of the matatas and the Maya who carried them.

“I started to put together where the tools are coming from and where they’re ending up,” Tibbits said.

She hopes to return to Central America and continue her research on the Maya and the potential of pXRF technology. In the meantime, the science department will be bringing pXRF technology to CSC this fall.

The next Graves Lecture will be Tuesday, March 29 with Joanne Hayes sharing How I Got Here. On April 12, Dr. Margaret Crouse will conclude the series with I Walked Where Jesus Walked.

—Abigail Swanson, College Relations