Rachanie Thosarat’s scientific contributions

em>The inland plains of Southeast Asia are a void in terms of early occupation by hunter gatherers. Two radiocarbon determinations from basal Ban Non Wat on the Khorat Plateau date a shell midden and possibly associated human and deer remains between 18000-20000 years ago. </em

The Iron Age of Mainland Southeast Asia began in the fifth century BC and lasted for about a millennium. In coastal regions, the development of trade along the Maritime Silk Road led to the growth of port cities. In the interior, a fall in monsoon rains particularly affected the Mun River valley. This coincided with the construction of moats/reservoirs round Iron Age settlements from which water was channelled into wet rice fields, the production of iron ploughshares and sickles, population growth, burgeoning exchange and increased conflict. We explore the social impact of this agricultural revolution through applying statistical analyses to mortuary samples dating before and after the development of wet rice farming. These suggest that there was a swift formation of social elites represented by the wealth of mortuary offerings, followed by a decline. Two associated changes are identified. The first involved burying the dead in residential houses; the second considers the impact of an increasingly aquatic environment on health by examining demographic trends involving a doubling of infant mortality that concentrated on neonates. A comparison between this sequence and that seen in coastal ports suggests two interconnected instances of rapid pathways to social change responding to different social and environmental stressors.

The 360 base-pair fragment in HVS-1 of the mitochondrial genome were determined from ancient human remains excavated at Noen U-loke and Ban Lum-Khao, two Bronze and Iron Age archaeological sites in Northeastern Thailand, radio-carbon dated to circa 3,500-1,500 years BP and 3,200-2,400 years BP, respectively. These two neighboring populations were parts of early agricultural communities prevailing in northeastern Thailand from the fourth millennium BP onwards. The nucleotide sequences of these ancient samples were compared with the sequences of modern samples from various ethnic populations of East and Southeast Asia, encompassing four major linguistic affiliations (Altaic, Sino-Tibetan, Tai-Kadai, and Austroasiatic), to investigate the genetic relationships and history among them. The two ancient samples were most closely related to each other, and next most closely related to the Chao-Bon, an Austroasiatic-speaking group living near the archaeological sites, suggesting that the genetic continuum may have persisted since prehistoric times in situ among the native, perhaps Austroasiatic-speaking population. Tai-Kadai groups formed close affinities among themselves, with a tendency to be more closely related to other Southeast Asian populations than to populations from further north. The Tai-Kadai groups were relatively distant from all groups that have presumably been in Southeast Asia for longer-that is, the two ancient groups and the Austroasiatic-speaking groups, with the exception of the Khmer group. This finding is compatible with the known history of the Thais: their late arrival in Southeast Asia from southern China after the 10th-11th century AD, followed by a period of subjugation under the Khmers.

The transition to states in mainland Southeast Asia began during the first centuries AD, and has commonly been ascribed to the adoption of Indian religious and political ideas which arrived on the maritime silk route. Recent research on the Khmer language inscriptions dating from 611 AD has revealed strong local traditions underlying the Indic veneer. In assessing these trends to increased social complexity, however, we have lacked insight into late prehistoric culture.

The archaeological implications of a palaeogeographical model of the region surrounding an archaeological site, Nong Nor, on the southeastern margin of the Bangkok Plain are presented. The regional stratigraphic sequence provides the basis for a regional palaeogeographical model extending from Pleistocene to late Holocene times. The model comprises three major phases of landscape development reflecting the evolution of the region's landscape from an inland undulating plain completely unlike the present floodplain, through a phase of marine inundation and coastal conditions, to the present freshwater floodplain environment.' This sequence provides a geographical framework for the prehistoric occupation of the midden at Nong Nor. In particular, it is possible to describe the landscape in which the prehistoric occupants lived and the distribution of environmental resources available to these people. The palaeogeographical model also provides a chronological framework for the prehistoric occupation of the site and the construction of the midden by reference to the timing of changes in environmental processes and conditions throughout the Holocene. Finally, the palaeogeographical model provides a basis for predicting the location and ages of other prehistoric sites within the landscape; in this respect, a geoarchaeological model partitions the landscape according to the potential for presence and preservation of archaeological sites of various types and ages. KEYWORDS: palaeogeography, geoarchaeology, site distribution, Holocene, Thailand, Southeast Asian archaeology.