The story of the Dead Sea Scrolls rivals that of comic book adventures. While in search of an errant goat, a Bedouin boy found a cave in the Judean Desert. Inside were ancient scroll writings, remarkably intact, awarding insight into the ancient Jewish people that populated the region.
With the authenticity of the scrolls confirmed in the late 1940s, the race was on to uncover further ancient writings in and around the first cave. Fifteen years and many caves later, archaeologists had located thousands of fragments at various locations. At the same time however, the Bedouin, with a wealth of local knowledge and an eye for profit, had located a number of fragments themselves.
In those exciting days of excavation and discovery there were no clear records of the location of finds. Furthermore, excavated materials were mixed with others purchased from local tribes. Although fragments have been grouped together based upon their content and layout, up until now it has been impossible to prove their relationship. New research from Ira Rabin and colleagues from BAM Federal Institute for Materials Research and Testing in Berlin highlights the use of sophisticated chemical spectroscopy methods to discover the origins of the writings.
The technique can identify the chemical makeup of a material by looking at its unique energy fingerprint. This uses the relationship between a material and the energy spectrum it radiates under certain conditions to determine which chemicals are present. Crucially, modern spectroscopy methods allow this to be achieved non-invasively, helping preserve precious ancient samples such as the scrolls.
The researchers first measured the relative amounts of the chemicals bromine and chlorine found in Dead Sea water. From this reference they were able to identify where the water used to create the ink and prepare the parchment came from, giving a location for the writing place of the fragments. Storage contaminants found on the scrolls, presenting as localised, distinct patches on the surface, provided knowledge of the sediments present in the caves where the scrolls were kept. Some fragments also showed isolated spots of salt where the skins were cured for storage for later use. Sediments of stone were identified only on the surface and not in the parchment core indicating this was a surface contaminant. Surface mineral deposits were linked to those found in specific caves in the Judean Desert.
Finally, parchments could be distinctly grouped into those in which tannin was and was not used as a preservative. A clear fingerprint attributable to tannin was visible between an eastern darkly tanned product and a western lighter, non-tanned parchment. This finding is fascinating in that it showes that there existed two geographically distinct methods of manufacturing parchment.
The key to the successful use of the technology in this study was the clever integration of different spectroscopic methods. This allowed the researchers to differentiate between chemicals used in production from contaminants. This has provided a wealth of knowledge from which it is now possible to unravel some of the mysteries of these ancient documents.
Rabin I, Hahna O. Anal. Methods, 2013,5, 4648-4654 doi: 10.1039/C3AY41076e. Characterization of the Dead Sea Scrolls by advanced analytical techniques.