Recep KARADAĞ
(Marmara University, Üsküdar, Turkey)
Keywords: Resin, analysis, horsehair, SEM-EDX
Abstract:
Salvage excavations conducted in the Yenikapı quarter of the historic peninsula of Istanbul by the Istanbul Archaeological Museums 2004–2013 have brought to light the Theodosian Harbour on the Sea of Marmara. In addition to thousands of archaeological artefacts, a total of 37 shipwrecks dating from the 5th to the 11th centuries AD were uncovered, constituting the biggest collection of medieval ships uncovered at a single excavation site. One of them is very important. The wreck (YK 12) was excavated together with its cargo of amphora. A separate compartment at the stern contained personal belongings, probably of the captain.
The wrecks contain different natural resins. Six resin samples were taken from different areas of the wrecks. The samples were analysed by FTIR. In the spectra of these natural resins the broad absorption bands at around 3500-3200 cm-1 can be attributed to the hydroxyl functional groups (OH stretching). Methyl and methylene stretches occur in the region of 2800-3200 cm-1. The peak at 1791 cm-1 in Sample 1 can be ascribed to the carbonyl group of anhydride or carbonate functional groups. On the other hand the absorption band at 1715 cm-1 is due to the carbonyl groups of ketone or carboxylic acid groups. The peak at 1640 cm-1 can be due to the double bond of the terpenes found in these natural resins. The strong peaks at around 1200 and 1200 cm-1 are due to C-O ether bonds. The peaks at around 1600, 1500, 1450 and 1410 cm-1 in Sample 5 shows the presence of aromatic units.
In addition to, the resins were analysed by SEM-EDX and optical microscopy. Horsehair was identified in the resins.
References:
Kocabaş, U. (2015): The International Journal of Nautical Archaeology (2015) 44.1: 5–38.
