The Luminescence Laboratory develops and applies new techniques for the dating of deposits and artefacts from sites that range widely in terms of chronological period, geographic location and material type.
The extension of the upper range of the method towards 1 Ma in being investigated by applying optically stimulated luminescence (OSL) measurement techniques to pebbles and cobbles in gravel deposits. OSL ages have been successfully produced for samples from independently dated contexts, including the lower gravels at the site of Swanscombe that were deposited about 400 ka ago. The extraction of samples from gravel exposures requires careful shielding using black sheet to exclude sunlight.
Funded by the Leverhulme Trust
We have established a new methodology for dating the subterranean aqueducts, commonly referred to as qanats, that have sustained past human settlement in arid regions (Bailiff et al., 2019; Bailiff et al., 2018; Bailiff et al., 2015). This type of irrigation technology is thought to have been developed in Persia during the first millennium BC and spread to Spain via the North African coast through Islamic influence. Although widespread, qanats are particularly difficult to date. Combined with information from excavation and archaeological survey of settlement and irrigation features, this work aims to enable an interpretation of their chronology. This approach has been tested by application to qanat networks in southern Spain and Morocco. In our most recent work we have found, contrary to its accepted Islamic origin in Spain, the OSL dates for a qanat system near Jumilla, Murcia, indicate significantly earlier origins of the technology, in the Roman period (Bailiff et al., 2019).
Image above: Sections through the excavated qanat mound showing a complex series of sediment layers associated with construction and use of the qanat
In related research, OSL and geomorphological techniques were applied to establish the chronology of canal irrigation systems and settlement sites associated with the demographic growth at the frontiers of the Sasanian Empire (Snape and Bailiff, 2020).This work formed part of a PhD project within a major investigation isupported by the European Research Centre and led by Prof. E. Sauer at the University of Edinburgh.
The availability of chronologies for aeolian horizons obtained using OSL provides a valuable tool in the study of the evolution of coastal landscape and how past coastal communities responded to climate change. The OSL dating of sands and palaeosol horizons, supported by geomorphological analysis, has identified critical stages in the development of the landscape on Herm on which megalithic monuments were constructed during the Neolithic period (Bailiff et al., 2014). The OSL dates identified three phases of significant aeolian activity during the prehistoric period, the onset dated to ca 4000, 3000 and 2300 years ago and evidence of ploughing activity was placed in the late 2nd millennium BC and in the 4th and 13th centuries AD. The testing of sediments directly associated with structures and monuments on Herm continues.
Image above: OSL sampling excavations on Herm, Guernsey
Image above: Isometric view of chalk surface of the Westcliffe site, showing solution features in which Middle Palaeolithic lithic artefacts were recovered
Horizons within a sequence containing Lower Palaeolithic artefacts on an upland site associated with a solution feature (doline) at West Cliffe in Kent were dated by OSL to between ca 140 and 80 ka ago, placing the deposition of the artefacts significantly later than indicated by the artefact typology (>300 ka). Contrary to the expectation of in situ burial indicated by earlier research, the cultural deposits were probably displaced from their primary context by processes associated with the development of the solution feature and this has important implications for establishing the timing of hominin use of the upland areas. Beyond broad attribution to Lower or Middle Palaeolithic origin the occurrence of displacement raises doubts regarding the interpretation of the environments that prevailed.
In this work we applied a novel extension of the single aliquot OSL measurement procedure that enabled single grain measurements to be performed with ~90 μm diameter quartz and applied to relatively fine-grained brickearth (Bailiff et al., 2013a) .
We have been at the forefront of applying luminescence dating to brick from medieval buildings in England (Bailiff, 2013b; Blain et al., 2010; Bailiff et al., 2010; Bailiff, 2007). Recent work included a comprehensive study of the construction history of St Giles House in Dorset (Bailiff, et al., 2017) led by Historic England and involving a number of specialists.
Image above: St Giles House, Wimborne St Giles, Dorset
Earlier work also included the dating of brick from medieval buildings in NW France with the University of Bordeaux III as part of a CNRS-funded GdRE network Ceramic Building Materials and New Dating Methods (Guibert et al, 2009).
A study produced, for the first time, absolute dates for a range of brick stupas located within the hinterland of Anuradhapura, contributing to the further development of a brick monument chronology for the region (Bailiff et al., 2013c). Ongoing work is examining brick structures from Buddhist sites in Nepal.
Image above: The Nawagala stupa showing (LHS) the extent of overgrowth in 2010 and (RHS) a scaled illustration of the monument showing the focal stupa constructed with ceramic brick and mounted on a large stupa