Monday, 5 September 2005

This presentation is part of: Poster Session I

The use of small-sample AMS 14C dating to resolve issues of occupation and demise at the medieval city of Angkor, Cambodia

Quan Hua, ANSTO, New Illawarra Rd., PMB 1, Menai, 2234, Australia, Dan Penny, School of Geosciences, University of Sydney, Sydney, 2006, Australia, Roland Fletcher, Department of Archaeology, University of Sydney, Sydney, 2006, Australia, Mike Barbetti, ACQUIRE, University of Queensland, Brisbane, 4072, Australia, and Christophe Pottier, Ecole Française d'Extrême Orient, Siem Reap, Cambodia.

Angkor was the capital of a vast medieval empire that incorporated most of mainland Southeast Asia at its zenith in the 12th/13th centuries AD. Angkor itself – a succession of state temples established between the 9th and 15th century AD surrounded by a vast penumbra of low-density residential settlement – is now known to be the largest low-density pre-industrial city on Earth. Despite its size, power and wealth, 19th-century European visitors found most of the Angkor region utterly abandoned. Unfortunately, the historiography of Angkor's final centuries is extremely speculative due to the lack of contemporary inscriptions and monumental construction. The reasons for Angkor's demise, and the timing and processes of Angkor's eventual abandonment, remain unknown.

Sediments that have accumulated in excavated cultural features, such as temple moats and reservoirs, offer an opportunity to infer changes in land-use over time and potentially demonstrate the timing of Angkor's abandonment. At Angkor, the moats represent the encircling oceans around the continent of Jambudvipa, upon which the sacred Mt Meru (the temple proper) sits. As they are central to the conceptual design and superstructure of the temples, their excavation is assumed to be coeval with the construction of temples they enclose. However, AMS 14C dating of sediment cores extracted from several temple moats indicates that sedimentation was initiated late in the classic Angkorian period, or even in the post-Angkorian period, long after the dates given for their excavation in the epigraphic record - more than five centuries later in the case of Angkor Wat. This implies that the moats were periodically re-excavated in order to maintain their depth and keep them clear of colonising vegetation. If this is indeed the case, then large, perhaps even centrally organised work forces may have been present in Angkor as much as two centuries after the city was supposedly abandoned.

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See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)