2,500-year-old wooden brazier with stones found in western China. Photo by Xinhua Wu
Traces of cannabis were identified in wooden artifacts that have been found in an ancient burial ground in western China. The wooden bowls are 2,500 years old, and the small stones and charred residues they contained are considered to be the earliest evidence of human cannabis consumption.
Wooden bowls as braziers for burning weed
Archaeologists and chemists from the University of Chinese Academy of Sciences and Chinese Academy of Social Sciences excavated 10 wooden vessels from burial sites at Jirzankal Cemetery on the Pamir Plateau in far-western China. Using gas chromatography and mass spectrometry, they analyzed the samples of the residue from the blackened stones and the charred portions of the bowls.
The researchers found that the wooden vessels were used as braziers for burning incense and plant matter, including cannabis. The residue had chemical signatures indicating high levels of tetrahydrocannabinol (THC), which is the main psychoactive or high-inducing ingredient in the plant.
Pot burning as part of burial practices
Aside from the wooden braziers, the researchers also retrieved other artifacts that included glass beads, pieces of silk, wooden plates, and harps. They also found skulls and bones with cuts and perforations, suggesting human sacrifice.
In a paper published in the journal Science Advances today, the authors wrote that from these artifacts, they can piece together an image of funerary rites that involved rhythmic music, flames, and hallucinogen smoke. These things are intended to guide the people into an altered state of mind. According to them, ancient mourners created smoke by placing hot stones in the braziers and laying in cannabis plants.
Where did the high-THC pot come from
The researchers noted that the high THC levels in the cannabis suggest that people in the area may have been cultivating these potent cannabis plants. The researchers compared the chemical signature of the Jirzankal samples against samples of the cannabis plants that have been discovered at the Jiayi Cemetery, which is around 1,000 miles to the east. The Jiayi burials dated from the 8th to the 6th century B.C.
They saw that the Jirzankal cannabis had molecular remnants of THC while the Jiayi cannabis did not. The cannabis strain found at Jiayi may have been primarily used as a fiber for rope and clothing, or as a nutrient-rich oilseed.
While the researchers were not able to determine the actual origin of the cannabis plants used in Jirzankal, they suggest that the region’s high altitude elevation — some 10,000 feet — on the Pamir Plateau may have put the local people in close proximity to the wild cannabis strains containing higher THC. Either that or the cemetery may have been sited at that elevation for the ease of access to desirable cannabis strains.
The researchers also said that another possibility for the high-THC strain is that traders may have unintentionally caused hybridization as they brought the cannabis plants along the Silk Road routes. The traders passed through the high mountains of the remote Pamirs, which connects present-day China, Afghanistan, and Tajikistan.