September 10, 2013
New Sourcing Technique Detects Obsidian In Seconds
April Flowers for redOrbit.com - Your Universe Online
Obsidian is a naturally occurring volcanic glass with a smooth, hard surface. It is far sharper than a surgical scalpel when fractured, making the glass a highly desirable raw material for crafting stone tools for almost all of human history. Found in East Africa, the earliest obsidian tools are nearly two million years old, and today, doctors still use obsidian scalpels in specialized medical procedures.
The chemical composition of obsidian changes from volcano to volcano. Each obsidian has a chemical "fingerprint" that allows researchers to match an obsidian artifact to the volcanic origin of its raw material. The testing for these fingerprints often involve dedicated analytical laboratories, even nuclear reactors, and take place months or years after an archaeological site has been excavated.
A new study from the University of Sheffield, UK, demonstrates a new method of sourcing obsidian artifacts, however, that only takes 10 seconds. The findings, published in Science Direct, reveal that this method -- conducted with a handheld instrument that can be used at archaeological excavations -- is dozens of times faster than the current methods.
Dr Ellery Frahm from the University of Sheffield’s Department of Archaeology explained, “Obsidian sourcing has, for the last 50 years, involved chemical analysis in a distant laboratory, often taking five minutes per artifact, completely separate from the process of archaeological excavation. We sought to bring new tools for chemical analysis with us into the field, so we can do obsidian sourcing as we excavate or survey an archaeological site, not wait until months or years later to learn the results. We can now analyze an obsidian artifact in the field, and just 10 seconds later, we have an answer for its origin."
“We carried out the research in Armenia because it has one of the most obsidian-rich natural and cultural landscapes in the world, and the lithic assemblages of numerous Palaeolithic sites are predominantly, if not entirely, composed of obsidian.”
This study is the latest in a series of achievements in the field of obsidian sourcing for Dr. Frahm. Prior to the current conflict situation, which now threatens the country's heritage, Dr. Frahm's previous research took place in Syria.
The department's involvement with the Marie Curie network “New Archaeological Research Network for Integrating Approaches to Ancient Material Studies” (NARNIA), gave rise to the current study. The NARNIA research at Sheffield unites archaeological lab work and fieldwork in the field. “We have a broad remit on the project, but we are driven by two goals: work where we couldn’t work before, and answer what we couldn’t answer before,” said Frahm.
“Here at Sheffield we’re shifting chemical analysis from the realm of ‘white lab coats’ to ‘muddy boots.’ The more that archaeologists and specialists in various fields can work together on-site the better.”