Archaeobotanical investigations at Khok Phanom Di, Central Thailand

Abstract

This thesis concerns the role of plants in the lives, and especially the diet, of the prehistoric potting community at Khok Phanom Di, a large mound situated on the Bang Pakong floodplain at the head of the Gulf of Thailand. The site lies on the southeastern seaboard, currently more than 20 km from the coast, but was occupied between 2000-1500 BC, on a higher shoreline. Excavations during 1985 involved extensive and systematic flotation to extract charred plant remains from a 500 year stratigraphy, almost 7 m deep. Charcoal, seeds and the remains of rice have been examined, together with remarkably well preserved coprolites, mineralised wood, and fibres, possibly the remains of burial shrouds. There were also impressions of leaves and stems for which identification has not been attempted. The archaeobotanical materials from the site contribute to environmental reconstruction and an understanding of the use of plant resources by this mangrove-based community. This archaeobotanical study stands in isolation in mainland Southeast Asia in its scope and methodology. Reference collections have been established and ethnobotanical surveys undertaken in the mangroves and adjacent lowlands of southeastern Thailand. Special emphasis was given to the taphonomy of rice. An ethnographic model of rice processing is explored. Comparisons between methods of post-harvest processing of rice and those for wheats and barley, show that rice waste products are less likely to be exposed to fire during processing, which helps to explain why rice is less well represented in the charred archaeobotanical record. Diagnostic criteria for distinguishing between the remains of wild and domesticated rice using SEM studies of lemma and palea features have been investigated. Reniform abscission scars and the absence awns in some of the archaeological husks suggest that the Khok Phanom Di people had access to domesticated rice supplies. Shell harvesting knives and stone hoes confirm that the community was involved in some form of cultivation, probably in ephemeral, freshwater swamps inland. This research has extended beyond the analysis of the plant remains to a broader view of the plant communities (mangrove, saltflats and freshwater swamps) within access of the site. Ethnographic, ethnobotanical and ecological observations are used are used to examine these habitats in terms of possible resource use, and thus to the broad subsistence base beyond the carbohydrate staple.