CEFOP receives prominent archaeologist

Dr. Christopher Stevenson travelled to progress in the investigation of obsidian hydration dating with Dr. Renato Saavedra. Both are developing a new photoacoustic method that will enable greater precision to the study.

From 8th until 20th december, Dr. Christopher Stevenson, archaeologist from the Richard Bland College in Virginia, visited for the second time to Dr. Renato Saavedra, a specialist in Nondestructive Materials Characterization of our, with the purpose of go forward in an investigation, to develop a new technique of obsidian hydration dating based in photoacoustic methods, collaboration which began in 2008.

Obsidian is a glassy rock of volcanic origin that through the centuries absorbs water from the surface of the earth. Dr. Stevenson’s research has been based on different methods for measuring the total amount of H2O present in the samples. From this information it is possible to determine the rate of absorption and therefore the date of origin of those samples, which in the Easter Island’s, where he began the investigation, are between 1000 and 1700 years old. “As the greater is the amount of water detected, it is estimated a faster rate of absorption, which determines a recent origin of the rock. Meanwhile, as drier it is, its dating increases”, explained the archaeologist.

Dr. Stevenson’s studies on this method have lasted for over 25 years, and particularly through the obsidian samples found on Easter Island. “This  research has evolved. What we are doing now in the photoacoustic laboratory with Dr. Renato Saavedra, is to develop a method based on photoacoustic infrared spectroscopy that will enable greater precision to the study” said Dr.Stevenson.

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