Filley, Fogel, and the King Midas Tomb

It’s not easy for archaeologists to reconstruct everyday practices of a past civilization, particularly since some of the most important evidence tends to degrade with the wood used for tools and other artifacts. Timothy Filley, formerly of the Geophysical Lab (GL) and now at Purdue; Marilyn Fogel, longtime GL Staff Member; and their colleagues were able to help with this problem in the Tumulus Midas Mound at Gordion, Turkey, by using a stable nitrogen isotope test.

Archaeologists had previously found that the wood remaining in the Midas tomb—from the coffin, tables, and furniture—was degraded more than would have been expected if the most common wood-eating microbe, Basidiomycota, had been at work. When the mound was first excavated, Basidiomycota was not present. Instead, the condition of the tomb—dry with evidence of leached alkaline water—was ideal for another organism of decay, the soft-rot fungus.

The soft-rot fungus typically eats the cellulose, hemicellulose, and lignin contained in wood tissue. When extra sources of nitrogen are present, however, the fungus proliferates. In keeping with ancient tradition, the person believed to be King Midas was buried with a bounty of food. The king’s body and the ceremonial food could have provided the extra nitrogen that would explain why the decay was so extensive.

The scientists used a stable nitrogen isotope test to answer three questions: What were the sources of nutrients the fungi consumed? Did microbial decay occur at different periods? And, was it possible to tell what the king ate?

The researchers used samples of the wood from the king’s coffin, the tabletops, and the structural parts of the tomb to measure the carbon-to-nitrogen ratios and the ¹⁴N and ¹⁵N values. Nitrogen enrichment is indicated when the ratio of carbon to nitrogen is low. The changes in the ratio come from the loss of polysaccharides and lignin and the nitrogen concentrated by the fungi. The scientists found that the samples from the tabletops and the coffin showed “dramatic nitrogen enrichments.” To determine the sources of nutrients, they looked at the isotopic composition of the wood. ¹⁴N is the nitrogen isotope most often found in nature. ¹⁵N, a heavier form, is more abundant in animals higher in the food chain. The researchers compared the ¹⁵N values from the tabletops and coffin and found that the fungi used three different sources for their food. The nitrogen on the tabletops is likely to have come from the food left for the king and the wood in the table. The high ¹⁵N from the coffin was from the king’s body. The elevated levels there indicate that a large part of the king’s diet probably came from meat. In addition, the scientists found that there were different episodes of decay. They believe that the fungi feasted on the king first and used his body as a base camp to colonize other parts of the tomb over time.

The researchers hope that their methods will prove useful in solving other, similar archaeological problems in the future. The study was published in the October 30, 2001, issue of Proceedings of the National Academy of Sciences.