Their micromorphological analysis found evidence of individual human activities, including the construction of hearths and bedding and the maintenance of occupational surfaces through the sweep out of hearths.
"I don't think we would have had this confirmation, or at least impetus, if we hadn't had done the original thin section work," said Goldberg. "We were able to recognize several different types of deposits that are only centimeters thick. Among them were layers composed mainly of phytoliths, some of which were clearly sedges," he said.
Phytoliths are minute particles formed of mineral matter by a living plant and fossilized in rock. In this case, researchers found fossilized sedge particles.
"We could also observe in thin section some pieces of clay that was likely attached to the roots of the sedges from where they were taken down at the stream below the site," said Goldberg.
In addition, the team's analysis confirmed the repeated burning of plant bedding. Most likely, "the bedding was burnt to rid it of pests--insects and perhaps rodents--and to clean up decaying organic material," said Wadley.
"Since sites are usually simply abandoned when they become fusty, the implication is that people wanted to reuse Sibudu regularly, and more regularly than would be allowed by natural processes of decay to clean the site. Burning was probably a more effective way to get rid of insects than the use of herbs."
According to Wadley, the discovery is particularly well timed, since future work at the site may be in jeopardy. Local officials plan to construct a large housing tract near the Sibudu rock shelter that Wadley says would irreparably damage the site and prevent future excava
|Contact: Bobbie Mixon|
National Science Foundation