Archaeologists finally date mysterious 'Plain of Jars' in Laos

It is not known for certain what the original purpose of the megalithic jars were, with the researchers saying that "remains a mystery."

Plain of Jars in northern Laos (photo credit: WIKIPEDIA)
Plain of Jars in northern Laos
(photo credit: WIKIPEDIA)
Archaeologists have finally dated one of the arcane scattered jar sites known as the Plain of Jars in Laos, according to a recently published study.
The sites feature large hollowed stone structures resembling jars spread across the hills and mountain ridges surrounding the central plains and upland valleys of the Xiangkhoang Plateau in northern Laos.
The jars can stand up to three meters in height, some up to three tons in weight, and each site hosts from one to hundreds of these stone megaliths, with a general belief they played a part in ancient burial practices.
Up until now, archaeologists have been unable to date the sites, although using geochronological analysis incorporating a technique called Optically Stimulated Luminescence (OSL), the researchers who led the study found a "likely quarry source" for one of the larger megalithic jar sites, and dated the stone structures to have been positioned at the site within the late second millennium BCE.
"The evidence provided by OSL dating has provided the first ever dates for the original placement of the jars... [to] 1240 BC to 660 BC," the researchers stated in their findings.
It is not known for certain what the original purpose of the megalithic jars were or how they got there, with the researchers saying that "remains a mystery."
Human remains as well as glass beads have been found in some of the jars, but it is unknown if the earliest structures were in fact burial places themselves. However, there is evidence pointing to the megaliths being used for mortuary purposes in more contemporary periods.
To further this notion, after running a comparative analysis of three of the megalithic jar sites (Site 1, 2 and 52), skeletal remains found at Site 1 were dated back to the 9th-13th century CE - centuries younger than the stone - giving the researchers the impression that the grounds could have maintained a ritual significance for thousands of years.
There is no evidence, however, that there were primary burials surrounding the positioning of the original structures, with the skeletal remains - thousands of years younger than the megaliths - only being found at Site 1, and a single dental specimen being located across the other two.
Additional evidence points to Site 1 being the expression of a single culture, while Site 2 and 52 could express that of another.
However, Site 2 and 52 did display "similar funerary hallmarks" compared Site 1, such as the use of limestone, boulders or chipped stone pavements as markers for possible burial sites, the researchers said, despite finding actual remains around the marks.
"Mortuary activity is noted at all three of the excavated sites based on similarities in the placement of limestone slabs over confirmed and suspected burials (soil acidity may have dissolved the bone at Sites 2 and 52)," the study authors said. "There are noted differences too as no ceramic jar burials, nor primary burials, were encountered at Sites 2 and 52 as they were at Site 1."
The researchers "strongly" believe, however, that the megaliths were placed before the site was decided to be used as a burial ground.
Radiocarbon dating of the earth beneath one of the jars at Site 1 gives notion that the jar was placed at the site at a later date than the OSL and uranium-lead dating place the quarried stone.
Researchers explained that "this latter date must be viewed, as described above, with consideration of an adjacent burial which may post-date the emplacement of the megalithic jar."
And while the original purpose of these megaliths still remain to be told, the research presented gives clear indication to the ongoing history of activity around the sites.
"The data presented here strongly suggests that the placement of the megaliths preceded the mortuary activity around the jars, indicating re-use of the sites and enduring ritual significance," the study authors said. "While the broad similarity in megalith morphology across Laos might suggest contemporaneity and the expression of a unique, yet to be identified, cultural group, more research needs to be conducted."