Luminescence Dating of Sediments from Droughduil Mound, Dunragit

This report presents details of the application of Optically Stimulated Luminescence (OSL) dating sediments from Droughduil mound, Dunragit. OSL dating operates by measuring the intensity of luminescence signals which are induced by long term exposure of minerals such as quartz to ionising radiation in the environment. OSL signals are bleached by exposure to daylight, and build up while the sample is enclosed in the archaeological monument. Providing the sample has been reset at time of deposition, the combination of OSL measurements of the radiation dose received and assessment of the environmental radioactivity of the sample and its context can be used to date depositional events. A series of samples were collected from Droughduil mound during a site visit on 29th August 2002. A total of eleven dating samples were collected from exposured sections using plastic tubing, and accompanied by in-situ measurements of the local gamma radiation fields of the site were used for dating measurements. Bulk samples were also collected for the purpose of laboratory gamma spectrometry . The quartz single-aliquot regenerative OSL dating procedure was applied successfully to all eleven samples. Radiation dosimetry combined field gamma spectrometry, thick source beta counting and high resolution gamma spectrometry. In all cases it was possible to use the OSL data to determine equivalent doses for the samples. A stratified sequence of dates were obtained from the base of the mound, indicating past land use stretching back to the mid 3rd millenium BC. Material collected from contexts thought to predate the cairn construction on the site, and others thought to post-date the cairn collapse, suggest construction and use of the cairn in the mid-late 2nd millenium BC

Luminescence Dating of Sediments from Droughduil Mound, Dunragit

This report presents details of the application of Optically Stimulated Luminescence (OSL) dating sediments from Droughduil mound, Dunragit. OSL dating operates by measuring the intensity of luminescence signals which are induced by long term exposure of minerals such as quartz to ionising radiation in the environment. OSL signals are bleached by exposure to daylight, and build up while the sample is enclosed in the archaeological monument. Providing the sample has been reset at time of deposition, the combination of OSL measurements of the radiation dose received and assessment of the environmental radioactivity of the sample and its context can be used to date depositional events. A series of samples were collected from Droughduil mound during a site visit on 29th August 2002. A total of eleven dating samples were collected from exposured sections using plastic tubing, and accompanied by in-situ measurements of the local gamma radiation fields of the site were used for dating measurements. Bulk samples were also collected for the purpose of laboratory gamma spectrometry . The quartz single-aliquot regenerative OSL dating procedure was applied successfully to all eleven samples. Radiation dosimetry combined field gamma spectrometry, thick source beta counting and high resolution gamma spectrometry. In all cases it was possible to use the OSL data to determine equivalent doses for the samples. A stratified sequence of dates were obtained from the base of the mound, indicating past land use stretching back to the mid 3rd millenium BC. Material collected from contexts thought to predate the cairn construction on the site, and others thought to post-date the cairn collapse, suggest construction and use of the cairn in the mid-late 2nd millenium BC

Dating a burnt mound from Kilmartin, Argyll, Scotland

Around 1600 burnt mounds, comprising heaps of fire cracked stones, up to several metres across with characteristic forms, are listed in the National Monuments Records of Scotland, with a diverse distribution. Many more are known in other parts of Europe, notably in Ireland and Scandinavia. Traditionally, these monuments are thought to relate to cooking activities throughout the Bronze Age though in recent years alternative functions have been suggested. Here results are presented from Lady Glassery Wood, a recently excavated site in the Kilmartin Valley. Samples for luminescence dating were collected in 1998, together with held gamma spectrometry measurements. Associated charcoal has also been subjected to radiocarbon dating. Despite and unusually low internal radioactivity from the rock samples examined, and low luminescence sensitivities from separated minerals, it has been possible to obtain concordant luminescence ages from both quartz and feldspars, giving a mean date of 2800 +/- 300 BC. Radiocarbon dating produces a 2 sigma calibrated age range of approximately 2800-2400 cal BC, in agreement with the luminescence age, indicating a late Neolithic date for the mound, one of a growing number of early dates in Scotland