Geoarchaeology of Thangsetthi, Tambol Nayang, Amphoe Cha-Am, Changwat Phetchaburi

Thungsetthi, a locality in Changwat Phetchaburi reveals its archaeological significance in historical period (6-10 C.E.). According to archaeological evidence, it can be assumed that Thungsetthi is situated on one of the ancient communication networks between central and Southern regions of Thailand. The research aims to analyze the relationship among geomorphology, sedimentology an archaeological evidence by using geoarchaeological techniques. The investigation by aerial photographs was the first approach, then, followed by ground reconnaissance and detail field survey. Field work includes geomorphological and archaeological mappings, coring with precision clement sediment corer and test pitting. Laboratory works include the detail log description of sediments, grain size analysis of sediments by laser granulometric technique, and detail analysis in archaeological remains. A result reveals that the change of landscape here has been occurring since the middle Holocene. The propragation of the land in eastward direction can be refereed relatively to the mid-holocene marine regression. Based on the archaeological sites and remains, the Dvaravati habitation site (6-10 C.E.) at Thungsetthi had been located on a beach ridge and barriers close to permian limestone hills and surrounded by aplaeo-channels connecting to the palaeo-shoreline. The progradation of the land during marine regression after the mid holocene might have played a significant role in controlling coastal landform pattern i.e. the change in direction of palaeo-channels. However, the morphological changes of the coastal area have been occurring until the present time. The investigation on coastal stratigraphy supports the evidence about the boundary of palaeo-shoreline. Furthermore, these palaeo-landforms especially beach ridges and sand barriers also represent that the people a Thungsetthi and other Dvaravati sites in adjacent areas selected the innermost sand barrier for their settlements and communication route since this sand barrier was stable and higher than the areas where were close to the shoreline at that time. Moreover, there are some channels that might be used as the transportation way to the sea. According to the archaeological evidence discovered from Thungsetthi, they can be correlated with major Dvaravati communities in central Thailand and suggest the idea that the holocene sand barriers were suitable for using as the communication route during Dvaravati period.