High-resolution dating of ancient ceramic kilns in Thailand, Laos and Burma by radiocarbon and palaeomagnetism

Full text: Radiocarbon dating is widely used on organic samples, especially wood, charcoal and bone. Classical techniques use samples of several grams, but only a few milligrams is needed for measurements by Accelerator Mass Spectrometry (AMS). Palaeomagnetic techniques are readily applicable to the study of ancient kilns. Core samples are drilled from the walls and floors, and oriented before being detached and measured on a sensitive spinner magnetometer in a laboratory. Resolution of a quarter of a century at 95% confidence can be achieved in favourable circumstances but only at certain periods of time. Radiocarbon dating shows that the earliest stoneware ceramics are from the 11th - 12th centuries AD and palaeomagnetism indicates that many in-ground kilns are of this age. Kilns of this type, which were hollowed out in sediments near river banks or old terraces, are found near Sisatchanalai in north-central Thailand and near Luang Prabang in northern Laos; they are similar in age to the Khmer-type kilns found at Suphanburi in central Thailand. A different type of kiln, constructed of bricks and located above-ground, appears towards the end of the 13th century AD. One of the earliest surface kilns at Sisatchanalai has a well determined date of 1290 ± 15 AD (calibrated radiocarbon age, 95% confidence).There is an overlap of the two technologies; stratigraphy and palaeomagnetic results show that in-ground and above-ground brick kilns continue almost side-by-side throughout the 14th century AD. One of the latest in-ground kilns at Sisatchanalai has a date of 1410 ± 25 AD (calibrated radiocarbon age, 95% confidence). There are many brick kilns belonging to the l5th century AD at Sisatchanalai, and they appear then at other sites in north-central Thailand (e.g., Sukhothai and Phitsanulok) and in Burma (e.g., Lagumbyee). In-ground kilns continue to be used in northern Laos even in the 15th century AD. The latest brick kilns at Sisatchanalai are 16th and possibly 17th centuries AD, as are the kilns at Singburi in central Thailand and the in-ground kilns at Vientiane in Laos