Characterization and dating of waterlogged woods from an ancient harbor in Italy

Waterlogged wood samples of Ulmus sp. and Fraxinus sp. from the ancient harbor of Otranto in Southern Italy were radiocarbon dated by accelerator mass spectrometry (AMS) and examined for physical and chemical changes to assess the degree of degradation. The analyzed woods were dated to the 2nd half of the twelfth – 1st half of the thirteenth centuries AD. The results of all the used methods (maximum water content, basic density, shrinkage, XRD analysis and holocellulose content) indicated a low level of degradation in the inner part of the wooden find. The outer and middle part, on the other hand, showed a greater degradation level. An important result is the identification of a not homogeneous degradation in the different parts of the examined wooden block, which will affect the design of the consolidating treatment.