Research at Boston University 2006

Bringing the Past to Life

Paul Goldberg: Reading Human History in the Earth

Geoarchaeologist Paul Goldberg studies the geology of archaeological sites. He compares analyzing layers of earth found at sites to reading “a crazy language where the translation code isn’t ready yet.” Unlike most archaeologists, who excavate while sweating under a hot sun, Goldberg mainly works in caves throughout Europe, Africa, and Asia that were home to early hominids, including Homo erectus, Neanderthals, and the earliest Homo sapiens.

Goldberg’s method of choice is micromorphology, the microscopic study of undisturbed sediments and soils. He collects blocks of sediment from archaeological sites, carefully packages them to keep them from falling apart, and ships them back to his lab at BU. There he soaks them in polyester resin, essentially turning the once loose sediment into a rock. He cuts the blocks into sections thinner than a sheet of notebook paper and studies them under a microscope, much as other geologists study rock samples. Under the microscope the sections reveal what is in the sediment and what mineralogical and physical changes have occurred. And because this technique preserves the original internal integrity of the soil/sediment sample and its individual components, Goldberg can also determine how the sediment was deposited, whether grains of sediment washed in or whether they fell from the roof of the cave.

The focus of the research is to understand how early hominids used fire. Archaeologists consider the ability to start and maintain a fire an important indication of a hominid’s cognitive development. Not only could fire-using hominids move into and exploit colder territories, they could also cook food, making it easier to digest and perhaps giving them an adaptive advantage.

But because these sites are so old, identifying fires can be difficult. Archaeologists working at the site of Zhoukoudian, in China, had claimed for decades that the site contained fires dating back almost 700,000 years. Although previous studies showed that they did contain burned bone and possibly organic matter, Goldberg’s examination of thin sections of the putative hearth layers revealed that sediment had been deposited by flowing water. He argues that any possibly burned material was in fact washed into the cave and was not evidence of fires as the original excavators had thought.

In his latest research project, funded by the National Science Foundation, Goldberg is studying fire sites from Neanderthal settlements in Europe and the Middle East with an international team of specialists from Spain, Germany, and Italy. These fire sites range from 50,000 to 200,000 years old. Goldberg calls the sites “mini-Pompeiis.”

By studying the fire sites microscopically and identifying the types of fuel used, how hot the fire was, and how long it was used, Goldberg and his associates hope to create a clearer picture of Neanderthal behavior. He hopes that by comparing Neanderthals’ use of fire with that of early modern humans, he can translate the traces of charcoal and ash into an understanding of what constitutes “modern behavior” and what might be some of the differences that helped humans survive while their Neanderthal cousins went extinct.

For more information, see http://people.bu.edu/paulberg.

— by Trina Arpin