Study on wood preservation state of Chinese ancient shipwreck Huaguangjiao І

Huaguangjiao І is a Chinese ancient wooden shipwreck of South Song Dyansty (1127-1279 AD). Wood samples from Huaguangjiao І were analyzed in order to evaluate the preservation state of the waterlogged wood. Samples were studied from the anatomical, physical and chemical point of view. Thin slides of cross and longitudinal sections from samples were observed by optical microscope, micromorphological decay was classified into class 3 or class 4 according to the anatomical characters. Water content and basic density were measured. Maximum water content (MWC) of the wood samples is between 300% and 600%, residual basic density is about 50%. The proportion of the α-cellulose decreased to 25% of the normal value, and the content of the ash increased greatly. These results indicate the degradation of the wood is very high. In addition, there is a plenty of inorganic deposit in the wood structure. The inorganic compounds deposited in wood samples were analyzed by XRD and ICP qualitatively and quantitatively. The morphology and composition of the inorganic deposit was characterized through SEM-EDS, the majority were iron sulfide, including pyrite and marcasite (FeS2), and fluorite (CaF2).