Sourcing obsidian artefacts in only 10 seconds

Archaeology News Network, 10-09-2013

Researchers at the University of Sheffield have developed a method of sourcing obsidian artefacts that takes only 10 seconds — dozens of times faster than the current methods — with a handheld instrument that can be used at archaeological excavations. Obsidian, naturally occurring volcanic glass, is smooth, hard, and far sharper than a surgical scalpel when fractured, making it a highly desirable raw material for crafting stone tools for almost all of human history. The earliest obsidian tools, found in East Africa, are nearly two million years old, and obsidian scalpels are still used today in specialised medical procedures.

The chemistry of obsidian varies from volcano to volcano, and the chemical “fingerprints” allow researchers to match an obsidian artefact to the volcanic origin of its raw material. The chemical tests often involve dedicated analytical laboratories, even nuclear reactors, and take place months or years after an archaeological site has been excavated.

The new process uses an analytical technique called portable X-ray fluorescence (pXRF), which involves a handheld instrument about the size, shape, and weight of a cordless drill. This portability enables archaeologists to identify the origins of stone tools in the field rather than having to send off artefacts to a distant lab. The newly developed method, which saves time and money, will first be used to study obsidian tools made by early humans, including Neanderthals and Homo erectus, tens of thousands of years ago.

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