McMaster Researchers Seek To Unlock The Mysteries Of Ancient Potters

By looking even deeper into the clay shards, the McMaster archaeologist will begin to understand the way Neolithic people lived, and in the process will dispel the myths and stereotypes surrounding ancient societies.

The making of ceramics is a long process, she says, as it requires the collection of raw materials (clays, inclusions, water and fuel), their preparation, the formation of the vessel’s shape, the finishing and decoration of the surface, drying and firing. "At each step potters have to make decisions about what material or tool to use and how to proceed," she says. "Their decisions are affected by several factors. Their environment will give them many or a few options of raw materials. The function for which they intend a vessel will also be important. A water jar must be able to hold water; a cooking pot must be able to withstand heat. Equally important will be the norms, traditions and organization of their society."

By understanding how the ceramics were made she can gain invaluable insights into how the Neolithic people interacted with their environment and with each other and how they lived their lives. Uncovering how they made their environmental, technical and social decisions by examining broken clay shards, however, is not easy. So she approached McMaster material engineers David Wilkinson and Patrick Nicholson for assistance.

Last summer, Michelaki participated in a three-month mission with the Bova Marina Archeological Project (BMAP), working on an archeological survey and excavations in Calabria, Southern Italy. She spent the summer, her fourth, examining shards and collecting clay that she, Wilkinson and Nicholson are now using to recreate ancient pottery at the Brockhouse Institute for Materials Research.

"What I wanted to do was to look at the society that had produced these ceramics and see what I could learn about those villages and the people who lived in them," says Michelaki. "In the summer I started examining the ceramics from a technological point of view to find out what materials people had used, how they had built them, how they fired them. But all of these observations that I made, especially about the firing stage, were macroscopic and general. In order to say anything more in-depth, I required the technical support and expert skills of material scientists."

With a two-year $40,000 Social Sciences and Humanities Research Council’s Research Development Initiatives grant, Michelaki, Wilkinson and Nicholson are collaborating to solve the mysteries of Neolithic firing techniques by combining archaeological observations with a variety of archaeometric techniques, such as X-Ray diffraction and scanning electron microscopy. With clay that Michelaki brought home from Italy, the researchers are recreating pots which they fire, controlling the atmosphere, temperature and heating rates to see what combination of conditions creates characteristics similar to those of the ancient ceramics.

"By firing the shards in a controlled way, you begin to see the shard’s story," says Nicholson. "For example, you can find out what temperature a shard was fired at by refiring it. You can do similar things with heating rate."

"We can do that here in the ceramic processing facility in the Brockhouse Institute for Materials Research," says Wilkinson. "We will analyze in great detail the chemical content and the microstructure of our experimental vessels and the ancient shards. By trying to make our replications similar to the ancient vessels we shall explore the conditions under which the ancient vessels had been made. By exploring those conditions we shall gain insights into the decisions the ancient potters had made and thus into their technical knowledge and skill."

Finding the answers is not an easy process. "In archaeology we can never know with certainty what happened in the past," says Michelaki. "The Neolithic potters may have had a variety of different ways of achieving the same results. We want to approximate the various options they would have had."

"By studying their choices of raw materials, forming techniques and firing technologies we can discover the ways in which they perceived and used their environment and the ways in which they interacted with each other," says Michelaki.

The researchers use local clays to make pots, similar to what the Neolithic pots look like, they fire them in open fires and then record in detail the temperature, atmosphere and heating rate throughout the firings.

The next step is creating clay briquettes and firing them in the laboratory, mimicking the conditions recorded in their experimental firings, but varying only one characteristic at a time; such as the temperature.

"We want to show that Neolithic technologies were far more complex than we have often assumed and Neolithic craftspeople far more skillful than previously thought. In the process we will also give archaeologists the tools and methodology to look at ancient firing technologies in a more sophisticated way," says Michelaki.

"It’s a long process and it’s a laborious process but it’s also very rewarding," she says, adding they are examining the entire chain of ceramic production at the same time; following the steps the Neolithic craftspeople had followed.

"We're doing this by combining our strengths in both the social and the natural sciences. The interdisciplinarity of our methodology and our holistic approach towards ancient technologies is the strength of our project."