Quest for Ash	April 7, 1997
by Haim Watzman

A team of researchers led by structural biologist Steve Weiner of the Weizmann Institute of Science has discovered a stable compound of ancient ash that promises to be a useful tool in identifying prehistoric human settlements. Using a portable infrared spectrometer, the team--mineralogist Solveig Schieg of the Weizmann Institute, archaeologist Ofer Bar-Yosef of Harvard University, and geologist Paul Goldberg of Boston University--made the discovery while analyzing sediments from two caves in northern Israel inhabited between 250,000 and 40,000 years ago. The researchers found that while a vast majority of the minerals that make up ash are highly reactive and soon decay, about two percent by volume are made up of a stable group of minerals called siliceous aggregates. These stable minerals allowed Weiner and his team to identify human habitation where no visible evidence of hearths remained.

© 1997 by the Archaeological Institute of America archive.archaeology.org/online/news/ash.html