长沙左家塘楚墓出土织锦的科技分析及石膏质盐害的识别OA

Silk textiles from the ancient state of Chu are famous for their distinctive artistic style and sophisticated craftsmanship,showcasing the impressive accomplishments in art,economy,and technology.The brocade,featuring red stripes and paired dragon-and-phoenix designs,was discovered in the Zuojiatang Chu tomb in Changsha and stands as a remarkable example of this tradition.It not only demonstrates the superb weaving techniques of the Warring States period but also provides valuable material evidence for the study of ancient textile technology and aesthetic concepts.However,silk artifacts are delicate,and textiles retrieved from waterlogged tombs in southern China are especially susceptible to fading colors,fiber breakage,and salt-related deterioration.These damages result from authigenic mineral crystallization,driven by groundwater infiltration,ion migration,and microbial activity. This study explores the pigment composition,authigenic mineral attachments,and the formation mechanism of mineral salt-related deterioration in the Changsha Zuojiatang brocade,aiming to elucidate the micro-mechanisms of silk degradation and its interaction with the burial environment,so as to provide a scientific basis for the conservation and restoration of excavated silk textiles. Optical microscopy was initially employed to scrutinize the textile structure,fiber morphology,and pigment distribution.Subsequently,scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy(SEM-EDS)was employed to observe the morphology and elemental composition of the surface particles and the attached crystalline material.Micro-area X-ray fluorescence imaging spectroscopy(MA-XRF)was used to perform non-destructive elemental mapping,thereby elucidating the spatial distributions of essential elements including Hg,S,Ca,and Fe.Finally,Raman microspectroscopy was utilized to determine the molecular structures of pigments and secondary minerals.The integration of non-invasive and minimally invasive multi-modal analytical techniques ensured the accurate identification of pigment origins,as well as the types,distributions,and formation processes of authigenic minerals. This study constitutes the systematic application of MA-XRF imaging to Chu-period silk textiles,successfully providing visualized mapping of pigments and minerals induced.Building on geological analytical approaches,the study proposed a bio-geochemical synergistic formation model for authigenic mineral salt-related deterioration in ancient cultural heritage,extending the interpretive framework beyond traditional craft-based explanations.MA-XRF imaging revealed that mercury(Hg)was highly correlated with the red decorative bands,confirming cinnabar(α-HgS)as the red pigment in finely ground particulate form.At the same time,iron-bearing contaminants were unevenly distributed across the surface.SEM-EDS and Raman analyses further showed the extensive occurrence of micron-sized gypsum(CaSO4·2H2 O)crystals—aggregates that are tabular,needle-like,or discoidal—with an atomic ratio of calcium to sulfur approximately 1∶1.The morphology and distribution of these gypsum crystals suggest that they are authigenic minerals formed either during burial under sedimentary conditions or post-excavation during storage,rather than residues of the original textile-making process.Their formation was likely influenced by microbial activity,organic matter degradation,and groundwater circulation.Improper post-excavation handling,particularly the absence of desalination and humidity regulation,further facilitated salt migration and recrystallization,thereby intensifying fiber hardening and breakage.The multi-modal approach exhibited notable complementarity among the techniques,underscoring their effectiveness in non-destructive analysis and the identification of micro-damage in delicate organic materials. This study presents a methodological case study to identify authigenic mineral salt-related deterioration in waterlogged silk textiles from southern China.The findings enhance our understanding of Chu-period weaving technology and the interaction between burial environments and material degradation,thereby providing valuable insights for the long-term preservation and restoration of other significant silk artifacts.Future research should incorporate isotopic geochemical analyses to trace sulfur origins and elucidate formation pathways,develop dynamic risk assessment and early warning systems for delicate organic relics,and further foster interdisciplinary collaboration among geology,mineralogy,and conservation science to improve the systematic preservation of excavated silk cultural heritage.