Testing 1D and 2D single-sided NMR on Roman age waterlogged woods

Waterlogged archaeological wood can provide information on past human activities and technology but its structure may be modified due to microbial deterioration. Knowing its conservation state is fundamental for its restoration. Aim of this work was to test the use of non-destructive portable NMR for the microstructural characterization and preservation state of three archaeological wood samples (Roman age, 5th century AD). 1D T-1 and T-2 relaxation time distributions, as well as 2D T-1-T-2 and D-T-2 distributions were measured by single-sided NMR and interpreted with the help of high resolution magnetic resonance imaging (MRI) and optical microscopy. Due to the complexity of the ancient wood samples, in this first study a multi-analytical approach was required. It allowed the characterization of both waterlogged soft-wood (spruce) and hardwood (chestnut and maple) by quantifying relaxation times and diffusion water components affected by the presence of degradation products such as fungi, paramagnetic agents, and microstructural changes. Optical microscopy was needed to investigate the sub-microscopic wood elements not resolved by MRI and validate indirect single-sided NMR investigations. Observations and results of this study will allow the improvement of single-sided NMR protocols for the analyses of archaeological wood in situ with portable NMR. (C) 2021 The Authors. Published by Elsevier Masson SAS.

Automated summary

This study evaluated the use of non-destructive portable NMR for the characterization and preservation state of waterlogged archaeological wood samples from the Roman period. The results of this multi-analytical approach allowed the quantification of relaxation times and diffusion water components affected by degradation products, such as fungi and microstructural changes, in both softwood and hardwood samples. The findings will contribute to the improvement of single-sided NMR protocols for in situ analysis of archaeological wood with portable NMR technology.