Scientists at the Australian Nuclear Science and Technology Organisation (ANSTO) are using their carbon dating facilities to shed some light on the mysteries of Cambodias medieval city of Angkor. Angkor is dominated by the remains of the massive Hindu temples, one of which, Angkor Wat, is listed as one of the architectural wonders of the world.
If you read the guide books, or visit Angkor Wat in central Cambodia, you are likely to be told the same story that the magnificent Hindu temples were abandoned after being over-run by invading hordes from Thailand in 1431, and that the ruins were left in the jungle until rediscovered by French explorers in 1861.
However, archaeologists now argue that the city may have continued to exist well into the 16th century. ANSTOs Dr Ugo Zoppi is working with a team of archaeologists from the University of Sydney. The archaeologists need ANSTOs expertise in radiocarbon dating using the accelerator at Lucas Heights, to piece together a more complete history of the habitation of the city.
Amongst the vanguard of studies into the ancient city is the University of Sydney team led by two associate professors, Roland Fletcher and Mike Barbetti, working with Dr Zoppi. The team is collaborating with APSARA, the Cambodian government agency that manages Angkor and EFEO, the French government agency that has studied Angkor for over a century.
Roland Fletcher argues that the key to finding out about the history of Angkor is to avoid the lure of the temples.
"You wouldnt visit St Andrews cathedral if you were looking to find out about the be everyday activities of people in Sydney. You would find out a lot more if you went out into the suburbs. The same applies to Angkor," he said.
While some archaeologists have spent a lot of time examining pieces of pottery and the carvings of the temples, Dr Fletcher has been knee-deep in historic urban detritus the rubbish discarded in the canals in the surrounding suburbs. It is here that he and Mike Barbetti are beginning to uncover the full story about the patterns of habitation of the ancient city.
In an area outside the walled centre of the city they have shown that people were living along the canals. Charcoal from the wastes that fell into the canal have been dated to the 12th and 13th centuries by Dr Zoppi. This confirms that people were living along the canals during the peak period of the city's history. The team is now turning their attention to the later occupation of the area.
Dr Fletcher theorises that the eventual abandonment of Angkor may have been caused by a number of different factors.
"Angkor ceased to be a major city at some time between the 15th and the 17th century but it is unlikely that the whole area was abandoned simultaneously," Dr Fletcher said. "One theory we are investigating is the possibility that the population declined due to an ecological crisis caused by extensive land clearance."
The carbon dating of charcoal from the rubbish in the canals of Angkor is only part of a major investigation by Dr Fletcher looking at the chronological framework of the occupation of the different localities in the ancient city. In 2002, Dr Dan Penny of the University of Sydney began a paleo-environmental project which will seek to date the major changes in vegetation between the 10th and the 16th centuries.