Jennifer Meanwell fastidiously positioned a pottery sherd — or damaged fragment of ceramic — beneath the round, diamond-coated blade of a benchtop noticed.
“Chopping the pattern is the primary huge step,” says Meanwell, a lecturer within the Division of Supplies Science and Engineering at MIT. She was main a lab in making skinny sections of pottery for petrographic evaluation, a technique used to look at ceramics and decide their composition, construction, and origins.
“You desire a slice that’s skinny sufficient to work with however thick sufficient to take care of its construction by way of the remainder of the method.”
The lab was a part of a summer season intensive course at MIT for PhD college students and early-career researchers in ceramic petrography, a specialised talent in archaeology. The course focuses on utilizing optical microscopy to characterize pottery from historical civilizations, revealing details about manufacturing methods and provenance.
Twelve college students from North America, Europe, Asia, and Australia participated within the three-week course in June to develop superior abilities, enriching college students’ understanding of historical ceramics and their broader historic and cultural contexts. It included morning seminars in mineralogy and archaeological principle and hands-on laboratories to determine and characterize supplies, perceive how they had been manufactured, and infer what they had been more than likely used for.
Meanwell and Senior Technical Teacher William Gilstrap taught the group find out how to study pottery samples collected from all over the world — Greece, Mexico, and the Center East — utilizing polarized mild microscopes to look at the supplies.
“Polarized mild will transmit by way of a mineral at 30 microns in a predictable method — it interacts with its construction, and the optical properties assist us determine which mineral varieties they’re,” says Gilstrap. By figuring out the minerals, researchers can hyperlink them to the geological panorama they got here from. “This helps us know extra about how individuals interacted with their environments, and maybe, how individuals transferred data on time and area.”
Fingers-on coaching
The course builds on the two-semester-long class Supplies in Historic Societies, run by the Heart for Supplies Analysis in Archaeology and Ethnology (CMRAE), a consortium of eight Boston-area colleges that gives coaching in archaeological and ethnographic supplies. Few establishments globally train ceramic petrography, and most present quick, one- to two-week programs.
Gilstrap highlighted the necessity for prolonged coaching. “It takes time to develop the abilities to search out the nuances within the construction in addition to to be taught mineralogy, geology, and the manufacturing methods of ceramics,” Gilstrap says.
College students be taught to reconstruct the manufacturing strategies of previous ceramics, from cooking pots to roof tiles, by analyzing the underlying construction of supplies to find out how they had been made. For instance, they will determine whether or not a vessel was crafted by pinching, a way during which a potter presses right into a ball of clay to type indentations, or coiling, which entails stacking rope-like strands of clay to construct up the vessel’s partitions. This evaluation can reveal manufacturing, transport, and consumption patterns.
“We will see the place issues are made. We will see the place issues ended up and path of change. And that’s the fundamentals of an financial system,” says Gilstrap.
The course blends sciences and humanities, overlaying fundamental chemistry, geology, and anthropological principle. College students additionally discover ways to make their very own petrographic skinny sections — slices of pottery impregnated in epoxy and mounted on glass slides. These sections are important for microscopic evaluation of the ceramic’s composition and construction. Most researchers, nonetheless, usually don’t make their very own skinny sections. As an alternative, they ship their samples to specialised labs, the place the preparation course of prices roughly $45 per pattern.
“When you could have 300 samples, that will get pricey,” Gilstrap provides.
Making use of new abilities
This sensible expertise resonated with Jean Paul Rojas and Michelle Younger, from Vanderbilt College’s anthropology division. As did all the scholars, they introduced in their very own slides for evaluation. Theirs had been made by a colleague 20 years in the past.
“These have by no means been petrographically analyzed, so it might be the primary time them and making an attempt to determine the petro teams,” says Rojas, a PhD scholar in archaeology. His analysis focuses on human migration, change, and motion within the Caribbean, notably the mineralogical origins of ceramics.
Earlier than the MIT summer season course, Rojas had little coaching in geology or mineralogy. Two weeks in, he joked, “I do know what rocks at the moment are.”
“Now I really feel like I understand how to essentially take a look at all these completely different minerals, the feldspars and the quartz and the plagioclase — the various kinds of feldspars — the micas, and I can determine them and make one thing helpful out of it.”
Younger is an assistant professor in Vanderbilt’s anthropology division and Rojas’ thesis advisor. She’s at all times had an curiosity in supplies science and ceramics, and he or she’s collaborated with a petrographer previously.
“However as a way to actually perceive the information, I wanted an introduction into the method,” Younger says.
When she returns to Vanderbilt, she plans on together with petrography as one of many methods featured in a lab sciences course for non-science majors.
“I’m hoping in some unspecified time in the future that I’ll ultimately publish on petrographic outcomes, or at the least use the method as a really preliminary method of grouping completely different ceramics,” Younger says.
One other summer season course scholar, Anna Pineda, a PhD candidate from the Philippines learning on the Australian Nationwide College, is analyzing jar burial websites within the islands and archipelagos between Southeast Asia and the Pacific Ocean. She’s notably interested by understanding how mineral evaluation methods in geology can inform archaeology.
“After I discuss to geologists, they will’t actually get what I wish to do except they’ve an archeological background,” Pineda mentioned. “It’s good to have a perspective from individuals who do archaeology.”
Pineda plans to include data gained from the course into her PhD analysis.
“Hopefully, I can get higher outcomes out of analysis on supplies which have by no means been studied but, utilizing strategies that aren’t generally utilized, in Island Southeast Asia.”
