An obsidian arrowhead: How old really?
Obsidianvolcanic glasswas a material of choice for prehistoric tool and weapon makers. Determining the age of the objects they left behind has always been a challenge for archaeologists. Several ORNL and University of Tennessee researchers are developing an analytical method for obsidian that has the potential of ensuring a precise means of dating archaeological sites. Prehistoric arrowheads, knives and spear points in many parts of the world, including Mexico and Central America, were made of obsidian flaked into very sharp cutting tools. Spanish conquistadors learned, to their annoyance, that a single blow from a good Aztec obsidian-edged sword could behead a horse. In modern times, obsidian has even been used for surgical scalpel blades. Unfortunately, developing a reliable method of interpreting the obsidian clock has defied all previous efforts. Now the team of scientistsusing secondary ionization mass spectrometry (SIMS), experimental calibration and sophisticated modeling method
