White halos surrounding the Dead Sea scrolls

The Dead Sea scrolls (DSS) are the most important archaeological find in Israel. Relatively well preserved in caves for 2000 years, additional damage has occurred since their removal in the 1950s. Among other issues, thousands of fragments were stored between glass plates, and over the years white “halos” formed around some of these fragments. Different theories about these “halos” have been proposed: the first, most obvious, option being salt migration. Since the salt content everywhere in the Dead Sea area (including aerosols) is extremely high, all of the scroll fragments would have collected large amounts of salt. Another theory, that the halos could be gelatin recrystallizing after being squeezed out of the degraded parchment, was more worrisome. If gelatin was squeezed out of the parchment, it would result directly in significant changes to the scrolls' physical properties. At the request of the Israel Antiquities Authority's (IAA) DSS conservation staff, we analyzed the powdery material with multiple methods: FTIR-ATR, Raman microscopy, XRD, ICP, and GC/MS. In addition to salt and minerals, our analysis found fatty acids (FA), but no gelatin, disproving that particular theory. By artificially aging modern parchment the phenomenon was recreated and the parchment samples were analyzed with destructive methods (electron microprobe, GC/MS) that could not be applied to the DSS in order to learn more about the process. The FAs are an important discovery not only for understanding the degradation process, but also as a source of information on the scrolls' production and treatment history - a source that can be analyzed even more accurately through destructive methods, without needing to touch the scrolls themselves.