Luminescence dating of qanat technology: prospects for further development

Abstract

With few exceptions in which dating is implied by indirect association with adjacent settlements or incorporation of diagnostic artefacts in upcast sediment, individual qanats have proven very difficult to date. This absence of a chronological framework hampers both our understanding of technology transfer, as well as the study of local settlement and landscape evolution and the temporal correlation of land use with climatic and palaeoenvironmental data. However, surface shaft mounds potentially contain a sequence of upcast deposits collected periodically from the tunnel, starting with initial construction and persisting until the last maintenance episode, less any material lost by surface erosion. The sedimentary nature of the upcast lends itself to the application of luminescence dating to determine the burial age, in particular, using the techniques based on optically stimulated luminescence. We examine the results produced by two recent dating studies where luminescence techniques were applied to two qanat systems with the aim of building a chronostratigraphy for the deposits within their upcast mounds. These studies show that the extent to which a complete record of the deposition since initial construction survives may differ between qanat systems, and even shaft mounds within the same system. Providing there is a close coupling of luminescence and sedimentological analysis in the testing of qanat mounds, these formative studies suggest that there are good prospects for introducing a valuable tool in the study of various types of hydraulic feature where upcast has been preserved and guidance regarding further fieldwork is provided.