Scientists Analyze Plant Material Found in the Great Wall of China and Discover Reed in the Construction Material.
Some of the oldest sections of the Great Wall of China were built using reeds and gravel. (Photo: Robert Patalano)
A team of archaeologists led by Dr. Robert Patalano from the Department of Archaeology at the Max Planck Institute for Evolutionary Anthropology analyzed the plant materials used in the construction of various walls and watchtowers of the Great Wall in northwestern China. According to a study published on December 29, 2022, in the journal Nature, the analysis of organic building materials provides insights into the environmental and climatic conditions of the area at the time of the Wall’s construction. Furthermore, the methods employed by the research team lay the groundwork for further applications of molecular technology, biochemistry, and advanced isotopes related to the environment, weather, and climate.
Rather than being a single monumental construction project, the Great Wall of China was built, repaired, and renovated by nine Chinese dynasties over 2,300 years. The new study provides additional evidence demonstrating that some sections of the Wall were constructed, subsequently modified, and repaired. Certain walls and fortifications date back to the Three Kingdoms period (475 – 221 BC). These sections were built using locally available bundles of reeds and wood, mixed with gravel.
The researchers specifically analyzed samples of reed. This large grass species grows in temperate and tropical wetland regions around the world. The team also compared the ancient reeds within the wall with modern varieties found in Gansu and Xinjiang through a combination of chromatographic techniques and isotopic analysis. They applied various techniques such as pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), fat density and distribution analysis, and carbon and nitrogen isotopes. Along with scanning techniques like electron microscopy, the research team found that most of the ancient reed samples were in a remarkably preserved state.
Through these samples, scientists can study and track historical climate and environmental changes along the eastern edge of the Tarim Basin during the Han Dynasty (170 BC). Significant hydrological changes due to climate change in the region only occurred after the Song Dynasty (1160 AD).
