Luminescence Dating of Brick Stupas: An Application to the Hinterland of Anuradhapura, Sri Lanka
Bailiff, Ian K., Lacey, Harriet R., Coningham, Robin A. E., Gunawardhana, Prishanta, Adikari, Gamini, Davis, Chris E., Manuel, Mark J., Strickland, Keir M., Antiquity
Buddhism swiftly became established as the state religion in Sri Lanka following its introduction in the third century BC (Paranavitana 1946), and this change was accompanied by the rapid development of Buddhist sites in both urban and rural settings (Coningham 1995). Identification of these sites is reliant on the presence of one or more architectural features, the stupa, the griha (sanctuary) and the vihara (monastery) being prominent types (Coningham 2001, 2011). The stupa is the most distinctive and durable of the monuments and, as the focal point of many monastic sites, it has become a prominent symbol of Buddhism in Sri Lanka (Silva 1986: 8). The origin of the stupa is thought to be pre-Buddhist, with a development traced back to megalithic mounds (Silva 1986: 6). Typically formed as a solid mound, the stupa was built primarily as a monument to enshrine relics or to commemorate important events or places in the life of the Buddha (Silva 1986; Coningham 2001). In Sri Lanka, the main building material used in the construction of ancient stupas was fired clay brick, a technology that, along with tile, was notionally restricted to religious or royal structures (Bandaranayake 1989).
The fortified city of Anuradhapura, a pivotal urban centre in Sri Lanka from the third century BC until its abandonment in AD 1017, witnessed a sustained and vigorous development of both secular and religious monumental architecture during this period (Coningham 1999, 2006). In the hinterland, monastic establishments developed a key economic and political role, acting as agents for the management of land and water, and providing an administrative infrastructure linked to the great urban viharas as an extension of their religious and secular influence (Coningham 2011). These rural monasteries were often located on granite outcrops, providing visually distinctive structures within the landscape of the hinterland, the topographic positioning of which has been linked to the concept of establishing intervisibility in the religious landscape as a means of increasing the visual prominence and authority (Shaw 1999). Recent archaeologicai work inthe Anuradhapura hinterland (Anuradhapura (Sri Lanka) project phase II: the hinterland) has focused on the relationship between urban and rural communities and the role of the development of Buddhist viharas within a broader landscape setting, including formulation and refinement of the monastic architectural chronology (Coningham et al. 2007; Coningham 2011).
However, the dating of stupas based on the use of architectural typologies is frequently not feasible in rural areas because historically original features were not preserved during renovation (Paranavitana 1946). Moreover, many stupas remained abandoned for centuries and were reduced to amorphous mounds, often structurally damaged by looting or robbed for the reuse of building materiais. This is a problem common to the stylistic dating of many brick Buddhist monuments in South and Southeast Asia, as discussed by Ali and Coningham (2002) working in Pakistan, Shaw (2007) in central India and by Stark et al. (2006) working in Cambodia, and there is a general need for a method of dating the construction of brick structures that is based on a direct analysis of the building materials.
This paper reports a study that examined the potentiai of opticaily stimulated luminescence (OSL) dating to test the chronology of a selection of brick-built stupas in the hinterland of Anuradhapura. Earlier work by Abeyrame (1994) on the application of thermoluminescence (TL) dating to archaeological sites in Sri Lanka included the testing of bricks from two urban stupas within Anuradhapura (Jetavanaramaya and Mirisewetiya) and a further stupa at Polonnaruva, and obtained good agreement with historical dates. However, no previous attempts have been made to apply scientific dating methods to stupas within the urban hinterlands. …