The stone jars are 1 to 3 meters high (about 3.2 to 9.8 feet), according to study co-author Nicholas Skopal, PhD candidate at the National University of Australia in Canberra.
Some of the vases have decorative carvings, while others are simple, he said.  About 65 jars have been discovered so far, but many more could be hidden underground, according to Skopal.
Researchers have not yet revealed the mystery of when these jars were made and what culture used them, he said.
A handful of sites in the area with the same stone jars were discovered by the British in the 1920s and before the Skopal excavation in 2020, there were seven known sites.  His team analyzed jars found at three of the sites.
While exploring the surrounding area, they stumbled upon four previously unknown sites with partially exposed jars, which was a pleasant surprise, Skopal said.
“With the right output, topography and documentation, the government and the universities can manage their heritage much better and preserve these jars for future generations,” Skopal said.


A HISTORY OF PEOPLE 
By the time the research team found the exposed jars, most of their contents had long since disappeared, Skopal said.
There is oral historical evidence of Naga, local villagers pulling beads and other objects from the jars, he said.  Although it is not known exactly when the beads were removed, as some of the locals still have them as family heirlooms, it is possible that they discovered the vases some time ago, Skopal added.
“In one of the villages we live in, one of the old ladies actually showed me (some jewelry) that had come out of the jar,” he said.
Similar jars have been discovered in Laos, and researchers there have been lucky enough to find jars that were still intact with objects such as beads and human remains inside, Skopal said.  He hopes his team will eventually find closed vases at the new Assam sites to study the culture they come from.
“Some of the buried may still have things inside, but we have not excavated yet,” he said.


AN UNSOLVED MYSTERY 
It is difficult to date when these vases were first created, so researchers are not yet able to determine which culture made the stone vases, Skopal said.
Early estimates date the artifacts to 400 BC.  or earlier, according to study lead author Tilok Thakuria, an assistant professor in the Department of History and Archeology at the North-Eastern Hill University Tura Campus in Meghalaya, India.
Determining the time period in which these jars were created is the team’s next priority, Skopal said.
To determine when the artifacts were buried, his team plans to use optically stimulated luminaires, called OSL.  This is a dating method where you take a sample of sediment just below the jar and determine when the light last struck that sample, Skopal said.
The date will correspond to when the jars were buried, giving researchers a much better idea of ​​when the jars were made.
Digging up closed jars will also help in dating the stone pieces, according to Thakuria.
“We need to have a plan for excavations in Assam to recover the material culture and reconstruct the social and cultural behavior of these groups of people,” he said.