Using Modern Tools to Reconstruct Ancient Life

SOIL SPEAKS Lint in samples from an ancient earthen floor in Ashkelon, Israel, revealed that clay cylinders found there were loom weights.

By SAM ROBERTS

Published: January 9, 2012

ASHKELON, Israel — To the naked eye, the white, powdery substance appeared to be plaster. That’s what the professional and volunteer archaeologists at a dig in Israel concluded.
To be certain, though, they subjected the chalky dust to spectroscopy and a petrographic microscope, only to discover that it was not a manufactured substance, but decayed plant life and fecal matter.

What that meant to the archaeologists from the Leon Levy Expedition to Ashkelon — a former seaport south of Tel Aviv that was home to successive civilizations over thousands of years — was that structures thought to have been inhabited by people were more likely occupied by animals. That revelation upended their view of what they were excavating.

“For archaeologists,” said the expedition’s co-director, Daniel M. Master, a professor at Wheaton College in Illinois, “it was the difference between a palace and a stable.”

This marriage of social and natural sciences is an emerging discipline that has been called microarchaeology by Steve Weiner, director of the Kimmel Center for Archaeological Science in the Weizmann Institute in Israel, which is collaborating with the expedition.

“The unique approach at Weizmann is not about instruments nor about methodologies,” Dr. Weiner said. “It is all about solving archaeological problems with the help of instrumentation — both in the field and in the lab.”

Weizmann archaeology researchers have a laboratory on the site here, along with equipment to study archaeometallurgy, ancient DNA, radiocarbon dating and micromorphology, the microscopic structures found in organisms and soil. A $2 million accelerator mass spectrometer is on order.

“We have developed a whole new integrative approach to archaeology that starts with the team identifying a good problem in the field and then continues interactively between field and lab,” Dr. Weiner said.

Dr. Master said: “Steve’s team demonstrated that the white lamina that archaeologists have routinely called ‘bits of plaster’ were actually degraded plant remains. Further, his team showed ways of analyzing these plants that could detect the difference between sheaves of grain and plant bits mixed into animal dung.”

Dr. Master and Lawrence E. Stager, director of the Semitic Museum at Harvard University, who has overseen the dig for 25 years, embarked on a mutually beneficial collaboration with the Kimmel Center after Dr. Master was invited to lecture there. Suddenly, new windows opened.

Sifting sediment through flotation turned up lint near mysterious clay cylinders. That discovery, Dr. Master recalled, demonstrated that the clay cylinders were actually loom weights, and “this observation has led to a revolution in the studies of the weaving industry across the eastern Mediterranean in the early Iron Age.”

Soil chemistry analysis found that a four-horned altar thought to be a traditional Levantine device for burning incense was not used for burning at all. Archaeologists identified it instead as a Mycenaean and Minoan libation altar on which liquids were poured.

“Our work with the Weizmann team has been a leap forward,” Dr. Master said.

Sharing workers and a mobile laboratory allows the expedition to analyze samples rapidly and adjust its excavating techniques accordingly. The application of pure science to practical challenges enables Kimmel Center experts to hone their research skills. The collaboration is not unique, but it is unusual for a discipline that falls between the humanities and natural science.

“In Israel, archaeology is taught in the faculties of the humanities, making it very difficult for archaeologists to fully exploit the powerful new scientific tools,” Dr. Weiner said.

“Although there is much good will both on the side of natural scientists intrigued by the exciting archaeological questions to be addressed and the archaeologists who are eager to obtain the information provided by scientific tools, a chasm of miscommunication exists between the two camps,” he said. “The frequent result is that minimal benefit is obtained from maximal effort.”

The collaboration with the Leon Levy Expedition, he said, means “we excavate, analyze samples in minutes, get results, change excavation strategy, sample as well as we can and then continue in the base camp lab and, between seasons, in the home lab.”
http://www.nytimes.com/2012/01/10/science/archaeologists-use-modern-tools-to-reconstruct-ancient-life.html?_r=1