The excavation of Non Muang Kao is a component of a major interdisciplinary project entitled "The Origins of Angkor", co-directed by Charles Higham, and Ratchanie Thosarat of the Fine Arts Department of Thailand. The research team includes experts in palaeobiology, human osteology, geophysics and remote sensing. The University of Bradford has sent specialists in palaeobotany, archaeometallurgy, and ceramic residue analysis. Dr Bill Boyd from Southern Cross University is studying the geomorphology of the area.
The principal thrust of this research programme is to examine the nature of societies which were responsible for the large settlements of the Mun Valley. During our first season, Non Muang Kao was excavated, a site which, with its channels, covers about 50 ha. In addition to opening a 5 x 5 m square in the centre of one of the two mounds within the enceinte, we also excavated across what were originally thought to be moats, over a linear distance of 60 m to a depth of up to 7 m, conducted proton and fluxgate magnetometer surface surveys, and undertook intensive surveys of the surface material.
Non Muang Kao, translates to "Mound of the Ancient City". It is a 50 ha prehistoric mound, ringed by at least two wide channels, parts of which contain water to this day. The mound itself is 300 metres in diameter and rises an impressive seven meters from the surrounding rice paddy. The only evident disturbance of the site has been the construction of a railway and a road, which destroyed the moats to the west and east of the mound. Non Muang Kao today, lies in extensive rice paddy, which stretches as far as the eye can see. The isolated location of Non Muang Kao has probably contributed to its preservation which clearly enhances its archaeological value.
Based on the recovered ceramics, Non Muang Kao appears to have been unoccupied since at least the early historic period, around 600 AD. It is expected that the site was first occupied sometime during the Bronze Age, and was inhabited through the Iron Age which began around 500 BC.
Non Muang Kao is located in Northeast Thailand, on the Khorat Plateau, about 20 kilometres from the city of Phimai in Nakon Ratchasima province. It is one of many similar sites located near the Mun River, a tributary of the Mekong.
The Khorat Plateau is bounded by the Phetchabun and Dang Raek mountain ranges which contribute to the climatic regime. A rain shadow effect causes the region to suffer frequent drought and the dry season is particularly long, lasting from November to May. Today the region is dominated by paddy fields, significantly different from the prehistoric environment which was largely dipterocarp forest with a large range of mammalian fauna. The Mun River catchment can be divided into three major environmental zones, the alluvial plain, the terrace zone and the uplands. The alluvial plain, once covered with lowland river forest and savanna grasses, is very flat and subject to flooding in the rainy season, yet it is the most suited for rice agriculture. The terrace zone comprises knolls and ridges formed by the old course of the river. The uplands are forested areas which rise 70 to 100 m above the alluvial plain of the Mun River. Non Muang Kao is located on the alluvial plain as are a significant number of prehistoric sites.
There is a paucity of scholarly literature in the area of state formation pertaining to Southeast Asia. The presence of walled and moated sites on the Khorat plateau has been noted since the 19th century. An invaluable source of information, in the form of military aerial photographs, was compiled after World War II. The first excavation of sites of this type occurred in 1955 when test pits were dug at Ban Thamen Chai and Muang Phet. Later the Thai Fine Arts Department surveyed moated sites in the Khorat region and dug test pits at two more sites. Non Dua, in Roi Et province was investigated by Higham and Parker (1970) revealing evidence of occupation from 500 BC and Ban Chiang Hian, in the Chi river valley, was occupied from 1000 BC.
Considerable attention has been given to the development of centres such as Phimai and a chronology for the surrounding region has been devised by David Welch (1984) based upon excavated ceramics. Aerial photographs have been used by Elizabeth Moore (1985, 1986, 1988, 1988, 1988, 1989, 1992) in a locational analysis and classification of moated settlements. This research hints at a hierarchical distribution of sites, which begs confirmation through excavation. More recently, John Parry (1992) has undertaken an examination of Landsat satellite images and conventional air photographs to categorise the main types of earth-works and demonstrate the value of this type of technology in settlement pattern analysis.
Southeast Asia is a region which remains little known archaeologically, and of all periods and sites, the so-called "moated" settlements of Northeast Thailand pose one of the most important and intriguing range of problems. Moated sites are documented in the Angkorian heartland, posited as seminal aspects of the later Khmer empire. The civilisation of Angkor was the leading pre-industrial state of Southeast Asia, but little is known of its origins. Most early research tended to focus on the role played by the process of Indianization in the rise of social complexity. The present research programme is designed to illuminate the indigenous late prehistoric culture and assess the nature of the transition to more complex political entities. The current political climate in Cambodia and a host of other logistical problems render an examination of these sites more feasible in Thailand. Recognised throughout Thailand and Cambodia, "moated" sites are especially densely distributed in the Mun river valley.
The current research seeks to expand upon that which has already been done. It is hoped that through targeting Ban Lum Khao, Non Muang Kao, and another site, Noen-U-Loke, that a more complete understanding of developmental processes in the Mun River valley will be attained.
There is no evidence of Neolithic settlement on the lower two thirds of the Khorat plateau. The basal dates of moated sites already excavated suggests an initial occupation of the area, sometime after 1400 BC, perhaps just before the widespread introduction of iron.
Non Muang Kao and Noen-U-Loke, both with Iron Age components, are being excavated to address a number of issues.
It is hoped that it will be possible to evaluate the relationship of Non Muang Kao and other moated sites both in close proximity and on a regional scale. Through an examination of the stratigraphic sequence and an analysis of the ceramics recovered, it will be possible to place the site in a solid chronological framework. It is expected that a comparison of the Bronze Age components from these sites as well as Ban Lum Kao will illuminate the question of cultural continuity between the Bronze Age and the Iron Age. If there was continuity it may be possible to identify the catalyst for the apparent nucleation of sites and a determination of which factors led to certain sites becoming centres. Further, the proposed research will determine the nature of the relationship between the sites, whether it was hierarchical or egalitarian. The possibility that these sites were central places to which the adjacent populace were bound is a tantalising possibility. The control of resources and trade may have underwritten an increasingly hierarchic social system. These possibilities can be tested through an examination of burial practice within these settlements.
The two large channels at Non Muang Kao, which extend over 80 metres, were excavated in 1996 by Dr Bill Boyd. He is hoping to ascertain the relationship between the moats and the ancient river bed. Archaeologically, we hope to determine when in prehistory the moats were excavated and what their purpose was. There has been speculation that they were constructed for a number of purposes including, defence, irrigation, horticulture, aquatic farming, water storage, or possibly, they held religious significance.
Archaeological work carried out during 1996-97 (see virtual excavation of Non Muang Kao) revealed a number of burials. It is anticipated that the analysis of the human remains as well as the accompanying grave materials will reveal a great deal about the social climate of Non Muang Kao throughout it's occupation.
Sometime around 500 BC iron technology was introduced to Northeast Thailand. It is critical to assess the role iron played in the development of the moated sites. The source of iron-ore is problematic. It may have either been imported or locally available, one possibility being the use of the abundant lateritic deposits in the soil. Evidence of smelting may indicate local availability whereas imported iron would only need to be smithed.
There are a number of less site specific questions which need to be addressed as well. We wish to examine settlement pattern and the role played by the moated sites. This will involve an assessment of prehistoric geographic, hydrologic and agricultural considerations in site location. One of the broader aims is to try and determine whether the moated sites constitute regional centres which sustained outlying hamlets.
At some point in the Prehistoric/Protohistoric period a great many "moated" sites were abandoned. A final consideration will be the reasons for the abandonment, whether they were social, political or environmental.
The cultural deposits at Non Muang Kao proved complex and excavation was very slow. Indeed, we only reached a depth of 1.7 m during the first season of excavation. Deposits at this depth, according to our radiocarbon determinations, date to the first half of the first millennium AD. We encountered a series of plastered floors, incorporating straight edges, postholes retaining the structure of the wooden posts, and graves lined with clay or plaster of some form. These graves contained thin Phimai Black pottery vessels, iron and bronze rings and glass beads. No complete interment, however, was found to match those found at Noen U-Loke (Wichakana 1991). Some pottery vessels were found associated with rich concentrations of rice. The charcoal used for radiocarbon dating came from unequivocally in situ contexts. The faunal remains from this upper layer included the remains of dog, cattle and pig of probable domestic origin and deer.
The excavation undertaken from December 1996 to January 1997 revealed many similar features to those uncovered during the previous season (see O'Reilly 1998). There were several more "clay" floors uncovered, some with evidence of internal wall structures and possible door ways. These floors were located directly below those found in strata excavated earlier, indicating continuity in the occupation of the site. Several more interments were uncovered. Although there was very little human bone remaining, the graves contained agate, clay and glass beads, copper alloy and bimetallic iron and copper alloy bangles, as well as very fine Phimai black bowls and pots. Most of the bodies appear to have been interred with copious amount of burnt rice.
Boyd's examination of the sections through the moats stressed the importance of excavation rather than reliance on air photographs. What appeared from the latter to be two moats turned out to be a river linked with two channels, the latter features being shallow and flat-bottomed. Before excavation, it was speculated that the moats might be deep with a v-profile and designed for defence. This is no longer tenable in the case of Non Muang Kao. Dr Boyd's research suggests that the "moats" actually represent ancient river beds which have been used for agricultural purposes after the river had moved away. These river beds would have contained rich alluvial deposits beneficial for agricultural purposes. It does appear, however, that Non Muang Kao was surrounded by water during its occupation, with the river partially ringing the site and a channel completing the ring. Boyd has taken organic samples in the hope that it will be possible to date their construction and through the analysis of diatoms, to assess the water regimes in prehistory.
The present research will, it is planned, not only make possible an assessment of the social, technological and economic life of a late prehistoric community, but also contribute an essential foundation to our understanding of regional developments. These, in turn, will clarify the nature of the societies which were prepared to incorporate certain Indian traits into their culture, while continuing such long-established practices as rice cultivation, water control, exchange in exotic goods and maintenance of ancestral cemeteries.
Dr. Dougald O'Reilly.