ASSESSING PORTABLE XRF DATA ANALYSES WITHIN A NEOLITHIC CONTEXT: COMPARING SEMI-QUANTITATIVE AND QUANTITATIVE XRF SPECTRAL DATA ANALYSIS OF YELLOW-CLAY FLOOR SAMPLES FROM STRUCTURE 14, NESS OF BRODGAR, SCOTLAND

An extensive hand-held XRF survey of yellow-clay floor deposits uncovered at the Ness of Brodgar, a multi-phased monumental-scaled Late Neolithic complex in Orkney, Scotland, provides an opportunity to integrate on-the-ground geochemical analyses with the on-site development of excavation strategies and site interpretation. The primary goals of the XRF studies are to help excavators delineate complex intermingling of contexts and to provide geochemical evidence to support the interpretation of the use of space within and between structures. Since 2010, XRF analysis has been carried out on floor samples from the major buildings at the Ness of Brodgar including Structures 1, 8, 10, 12, and 14. From 2014, XRF analysis has been carried out using a site-wide 50 cm X 50 cm sampling grid. This study reports on the complete spectral dataset from Structure 14 with the aim of assessing the effectiveness between a semi-quantitative method of data analysis where each individual analysis is normalized by the run’s elastic-scatter to quantitative data analysis using a mudrock reference collection. The study assesses whether handheld XRF data may be used to effectively distinguish and characterize archaeological materials when no suitable standard reference collection is available.